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Патент USA US2106167

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Jan. 25, 1938.-’
H, D, cOLMAN '
'
2,106,167
‘SELF ADJUSTING BRAKE
'
Filed March 15, 1935
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INVENTOR
Howard D. ÚO/mdn
BY
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¿jl 5M, MW» ‘21PM ’LM
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ATTORNEYS
Jan. 25,. 1938.2
2,106,167 V
6 Sheets-Sheet 2
Filed March 15, ‘ 19:55l
INVENTOR
_
Howard .D. Colman
,BY
A
M60,
ATTORNEYS
Jan. 25, 1938.
'
`
H. D. coLMvAl-u
SELF
ADJUSTING
BRAKE
Filed March 15, 1935 ~
2,106,167
'
'
s sheçts-sneèt :s
Jan. 25, 1938.
' H, D. coLMAN
Y2,106,167
SELF ADJUSTING BRAKE
Filed March l5, 1935
S#
miz
6 Sheets-Sheet 4
Jan. 25, 193s.
.H „_ COLMAN
>2,106,167
SELF ADJUSTING BRAKE
Filèd March l5, '1935
6 Sheets-Sheet 5
Jan. 25, 1938.
HD. CQLMAN
'
_ 2,106,161
SELF ADJUSTING BRAKE
,
'Filed March 15, 1935 ~
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A ORNEYS
2,106,167
_Patented Jan. 25, v1938
UNITED STATES
PATENT OFFICE _
2,106,167
ì
l
SELF-ADJUSTING BRAKE
Howard D. Colman, Rockford, Ill.A
Application March 15, 1935, Serial No. 11,352
40 Claims.
(Cl. 18S-79.5)
The present invention relates generally to im
provements in brakes for rotary members, and
more particularly to vehicle brakes which are
self-adjustable to compensate automatically for
The invention is especially suited for automo
bile brakes which commonly have a plurality of
anchored or ñoating shoes or a°band, and actu
ating means manually operable from a foot pedal
10 for expanding the shoes or band outwardly into
frictional engagement with a rotatable drum.
The actuating means maybe any one of a well
‘
_
acter which is self-adjustable to compensate au
tomatically for wear on the brake lining, which
issen'sitive and accurate inv operation, which is
not subject to adjustment by vibration or other l
extraneous forces, and which will not be inñu- 5
enced by grit, dirt or other foreign matter, but
will remain eiìcient in operationthroughout its
required life.
ì
`
A more specific object is to provide the oper
able braking element with a plurality of novel 10
radialclearance stops self-adjustable to com
pensate for wear, and a novel circumferential
chanical, hydraulic, vacuum, air pressure, mag
connecter for separate parts of the element, such
as shoes or sections of‘a drum, self-adjustable to
stantially constant and uniform throughout the
hicle brake assembly with radial clearance stops
entire life of the brake lining so that the range
20 of movement of the actuating means will remain
ñxed in phase and extent, and that the action of
screw members having non-locking threads, one
known number of types, for example, the me
15 netic, or “so-called” power type. For eiiicient compensate for expansion >of the element by the“
braking, the amount of movement required for 'radial stops, and thereby to maintain-the motion
actuation of the internal braking element into of the brake actuating means constant.
Other objects reside in the provision of a ve
engagement with the drum should remain sub
the various brakes of the automobile will always
be equal.
2
,
-.
The brakes now in common use do not satis
factorily fulfill these conditions. Asv wear on
the lining occurs, the applying movementÀ in
creases, thereby increasing the required move
ment of the foot pedal. Hence, approximately
O
two-thirds of the motion of the foot pedal is uti
lized to cover the wear range, and _only the re
maining one-third thereof is available for the
operating range. To keep the maximum range
of pedal movement down to a. practical limit, it
35 has therefore been customary to provide foot
pedals having a relatively small leverage and re
quiring a correspondingly large force. If the
pedal movement were always available to cover
a constant operating range, a much greater lev
40 erage could be employed to lobtain a heavier brak
ing action with the same manual eiïort. Without
self-adjustment for wear, the braking action on
the various wheels of the automobile also tends
to become unequal. This is particularly objec
tionable in front wheel brakes because of its
effect on steering in various commonly-used con
and a circumferential connecter of the foregoing zo
character, each of which comprises two coacting
member being axially movable from an idle posi- '
tion ñrst through a predetermined clearance and
then to effect relative rotation between the mem
bers by reason of the coaction of the threads,
brake means for resisting such relative rotation,
and clutch means for preventing such relative ro
tation when said one member is in idle position.
A further object is to provide novel means for-
preventing misadjustment, and particularly over-I
adjustment, as a result of the violent accelera
tions to which the adjusters may be subjected in
the normal use of the vehicle.
`
`
An important object -is to provide a novel ex- 35
tensible housing for hermetically sealing each
screw device within an enclosed space adapted
to contain and retain a lubricant for the moving
parts, and serving to 4exclude completely all dirt,
grit and other foreign matter which would ln- 40
terfere with satisfactory and continued operation.
Still another object resides in the provision of
a new and improved means for resetting each `
screw. device without breaking the hermetic seal
upon replacement of the brake lining.
45
Further objects reside in the provision of a. ,
vnovel magnetic power actuator for the brake.
structions.
'
Other objects and advantages will become ap
One of the primary objects of the present in
vention therefore is „to provide a vehicle brake parent- as the description proceeds.
In the accompanying drawings, Figure 1 is an 50
su with novel means for limiting the retractile
movement of the operable friction element and axial sectional view, taken along line I--l of Fig. _
the actuating means therefor to a predetermined 3, of a wheel brake embodying the features of
clearance at all times.
_
A further object resides in the provision of
my invention.
Fig. 2 is a .fragmentary axial section of the
55 new and improved means of the foregoing char- y brake taken along line 2-2 of Fis. 3.
2
Fig. 3 is a transverse sectional view of the en
tire brake taken along line 3-3 of Fig. 1', and
illustrating the location of the various self-ad
justing devices.
_
-
for expansion and contraction through a brak
ing clearance. Channel-shaped brackets 2li and
2|, with inwardly extending longitudinalparallel
side flanges 22 and 23, are secured respectively
to the inner surfaces of the ends of the band I8,
larged scale, taken along line 4_4 of Fig. 2, and " and have flat end faces 24 and 25 adapted to
-illustrating one of -the self-'adjustable radial engage respectively with opposite lsides of a
clearance stops.
_
bracket 26 rigidly mounted on the backing plate
Fig. ,5 is a fragmentary axial sectional view I1 and vconstituting a stop abutment. Suitable l
taken along line 5-5 of Fig. 4, and illustrating tension springs 21'are anchored at their oppo
the means for resetting the adjusting mechanism. site ends to the brackets 20 and 2|, and tend to
Fig. 6 is a transverse sectional view, on a -still retract the band I8 from the drum I5. 'I'he end
Fig. 4 is an axial sectional view, on an. en
larger scale, takenialong line 5_6 of Fig. 4.
Fig. 7‘is a fragmentary detail view showing a
15 portion of the adjusting mechanism in side ele
vation.
20
-
Fig. 8 is a fragmentary longitudinal sectional
view, on an enlarged scale, taken along-line 8-8
of Fig. 3, and illustrating the circumferential
connecter.
-
-
Fig. 9 is a transverse’sectional view of one of
the' clutch elements of thé circumferential con
necter taken along line 9-9 of Fig. 8, the exter
nal enclosing parts being omitted.
25
-
Fig. 10 is a fragmentary sectional View taken
along line Ill-I0 of Fig. 8, and _illustrating the
resetting means.
`
`
Fig.- 11 is a >fragmentary-side elevational view'
faces 24 and 25 also respectively engage suitably
rounded cam abutments 28 and 29 on two trans
versely disposed cam levers 3I|«and 3| pivotally
` mounted at their outer ends on the bracket 26.
lus
The inner ends`of the levers 30 and 3| are formed
with oppositely inclined faces adapted to engage
opposite sidesv of an' actuator pin 32 when in
retracted position.
Any suitable means may be provided for mov- '
20
ing the actuator 32 c_ircumferentially of the
brake in either direction out -of the neutral posi:
Y tion shown in Fig. 3 to apply the brake, and in '
the present .instance this means is shown as an 25
electromagnetic pilot clutch 33 (Fig. l). ` In its
preferred form, the clutch 33 comprises an annu
lar magnet 34 mounted for limited rotation on
illustrating _the means for preventing adjustment
30 when the parts are subjected to an excessive axial «_ thev backing plate I1, andan axially movable
amature 35 rotatable with the drum I5. The 30
acceleration.
magnet 34 consists of an annular'coil 36 mounted
-Fig. 12 is Aa transverse sectional view of another ‘ within a housing 31 of magnetic material U
form of- wheel brake embodying the self-adjust- - shaped in cross-section and having' inner and
ing devices. f
_
~
Figs. 13 and 14 are fragmentary sectional views
outer concentric flanges defining pole faces 38
and 39 at their outer edges. A flat ring 40 of 35
taken respectively -along lines I3-I3 and I4-_I4 . a >suitable friction material is seated against the
coil 38 between the pole faces 38 and 39, and is
Fig. 15 is a sectional view on an enlarged scale". substantially flush with the latter. A'I'he coil
of Fig. 12.
taken along line I5-,IV5 of Fig. 12.
' housing. 31, to one side of which the actuator pin
Fig. 16 is a sectional viewlon an enlarged scale i 32, is rigidly secured, is rotatably mounted and
40
taken along line I8-I6 of Fig. 13.'
axially positioned in Van annularv seat or notch. 4|
'I'he present invention in its broad aspects is , formed in the end> of a concentric flange 42 on
adaptable to different brakes for-a large variety the inside of the backing plate I1. A thin bear
of purposes. It is especially suited for and hence '
45 disclosed in connection with an automotive _ve-~ ing ring 43 preferablyds interposed between the
housing 31 and _the cylindrical surface of the 45
hicle wheel brake. One particular type of wheel seat 4|.
V
'
’
brake is- shown, but it is to be understood that
The armature 35 is in the form of a ñat annu
theinvention is not Hunted in all respects to any
o'ne type or to the preferred details of the self
50
-
55
adjusting devices, but is intended to cover all ' 44 froml an outwardly spaced annular flange
equivalent, modified and alternative 'construc
member 45 secured to the Adrum I5.y The straps 50..
tions coming'with'in thespirit and scope of the "44
extend along chords of the circumference of
appended claims. _
~
the
flange member 45, andhence will resist the
Referring more particularly to the drawings, rotational
torque when subjected to tension as in
the brake is mounted on the front wheel II of a
The wheel II com_
prises a central disk I2 suitably mounted li'or
‘ - truck or other motor vehicle.
' rotation on an axle I3, and a flange I4 ~for sup
porting the rim (not shown). _
In its preferred form, the brake comprises a
cylindrical drum I5 rotatable with the‘wheel II.
Q In the present instance, the drum I5 has an.an. nular flange I8 at one end rigidly secured be
tween the disk I2 and flange I4, and is open at
65 the other end. A stationarybacking plate I-1Avis
mounted within and substantially closes the in
- „
7
lar disk of magnetic material, and is supported
.for axial movement by a plurality of spring straps
ner end of the 'drum I5.
one direction of rotation. Interfitting radial and
laterally projecting lingers 48 and 41 respectively
on the armature 35 and flange member 45 are
provided to take the rotational torque in the
l reverse direction.
-
To prevent lubricant in the wheel bearing from 60
reaching the friction surfaces of the‘ clutch 33,
apacldng 48 is interposed between the hub of 'tlze
disk I2 and the backing plate I1. -Two overlap
Ding bailles 49 and 50 are provided to direct any
lubricant that may escape from the`wheel bear 65
ing to a plurality of discharge openings 5| in the
disk I2. Preferably.v the baille 49 is conical in
The brake preferably isof .the internal type . shape and secured to the disk I2 closely about the
with its mechanisml mounted within the enclosed series lof openings 5I, and the baille 50 isv cylin
space between the disk I2 and the plate I1, and drical in form and secured to the backing plate
70
comprises a braking element I8 with an ,external I1 and projects intothe baille 49.
‘A
brake lining I9 movable into and'out of frictional
The armature 35 is held in direct bearing en
engagement with the interior of the drum I5'. gagement
with the magnet 34, and completes
The braking element I8 is shown in the form of lthe ilux circuit across the pole faces 38 and 39.
a yieldable circumferential split» band adapted
When the brake is released, the friction surfaces
3
2,106,167
of the clutch 33 slipsince the pressure exerted by
the spring straps 44 is light. To apply the brake,
the coil 36 is energized; Control means for this
purpose are well-known in the art, and hence no
speciñc means is disclosed herein. For automo
bile or truck brakes, the circuits for the coil 36
may include a rheostat switch (not shown) op
erable by a brake foot pedal (not shown). Upon
such energization, the pull on the armature 35
ll) increases the clutch pressure suiîiciently to ef
fect rotation of the magnet 34 and the pin 32.
If the drum I5 is rotating in one direction, as in
forward travel of the vehicle, the pin 32 will actu
ate the lever 36 to impart- braking pressure to the
15 end 24 of the band I8. This pressure will be
transmitted through the band I8 against the re
mote side of the abutment 26, and will cause ex
pansion of the band into frictional engagement
with the drum I5. Since the brake band I8 is
Upon
reverse rotation ofthe drum I5, as in rearward
travel, the lever 3l will be actuated to apply the
20 yieldable, a servo-action will be obtained.
brake in a similar manner.
When the coil 36
is deenergized, the springs 21 will retract the
band I8 and return the parts, namely the band
ends 24 and 25, the levers 30 and 3l', the pin 32
and the magnet 33, to centered or neutral posi
tion.
>
Means is provided for automatically adjusting
30 the brake to compensate _for wear ‘on the brake
lining I9. To fully compensate for the effects of
35
wear, the adjustment is made to carry out two
functions regardless of the form or type of the
brake to which the invention may be applied.
The first functionV is to maintain 'a‘ constant
tuator 32, for two sections |83 and I8b of >the
band I8.
The radial clearance stops 52 are alike in con
struction, and hence a description vof one will
suffice for all. The stop 52 illustrated in Figs. 4 Ul
to 7 comprises inner and outer screw members
l54 and 56 having c'oacting non-locking threads
55 and 51.
One of the members 54 and 56 is
adapted vfor axial movement radially with the
band I8, while the other is adapted for engage io
ment with a stop shoulder 5,8 to limit its outward
Also, one of the'members is
' axial movements.
mounted for rotation, while the other is non
rotatable.l In the present instance', the inner
member 54 is rotatable, and adapted to be re
15
strained againstsubstantial outward movements
by the shoulder 58, and the outer member 5'6 is
non-rotatable, and free to move -axially with the
band I8 upon applying and releasing the brake.
The member 56 may be held against rotation iny 20
any suitable manner, and preferably is formed
externally with a plurality of longitudinal splines
forming part of a spline connect-ion 56a referred
to hereinafter. Thus,- the screw members 54 and
56 constitute a self-adjustable device in which 25
thenon-locking screwthreads 55 and 51 will ef-i
fect a relative rotation and hence an automatic
elongation when subjected tó axial stress.l
To permit a limited outward movementof the
screw member 56 through the desired radial brak 30
ing clearance without eiîecting an adjustment, a
lest motion is provided which must be taken up
before the threads 55 and 5l will be subjected
to an appreciable axial stress. In the present
instance, the lost motion is provided for by mount 35
ing a fixed rest or stop 58 in position for engage
ment by the inner end of the screw member 54 to
limit the retractile movement of the member 56
predetermined clearance between the drum I5
and the braking element or band I8. In the
brake illustrated in Figs. 1 to- 11, a plurality of
and hence of the band I8, and by spacing lthe
radial clearance stops 52, which are self-adjust
able to compensate automatically for wear on the stop 59 an axial distance'from the shoulder 56
such that the members willmove outwardly as a
brake lining I8, are mounted in position to sup
port the braking element or band I8 when the floating unit through the desired distance vbefore
brake is released. In- the present instance, four ` the member 54 will engage the step shoulder.
During the application and release of the
of the stops 52 are shown in a particular environ
ment and relationship to the braking element I8, brake, the screw member will move between the
45 but it is to be understood that the expression shoulder 58 and thestop 59, and while the brake
is applied may besuspended therebetweenif the
“radial clearance stop” or any equivalent ex
pression, as used herein and in the appended braking clearance is less than the desired max
imum. The weight of the movable parts, vibra
claims, is intended to define any suitable ad
justing means which will automatically perform tion,=','sharp accelerated movements of the wheel
50 the first function to insure that the radial clear
axle particularly in directions' generally parallel
ance will be substantially uniform throughout to the axis of the stop 52, and other extraneous
influences, such as are commonly encountered in
the circumference, Aand will remain substantial
, motor vehicle operation, if not rendered inef
ly constant for the life lof the lining I9.
fective, would be likely lto cause misadjustment. ,
The second function is to maintain substantial
55
ly constant the extent of movement of the brake Hence, a brake 60 (see Fig. 6) is provided to im->
part a slight resistance to rotation of the screw
actuator regardless of adjustments for maintain
ing a constant braking clearance. This function member 54. Since stresses set up by accelerated '
may be carried out in any suitable manner, and
preferably by adjusting the circumferential di
mension of the braking element and actuator as
sembly in accordance with changes in the idle
position of the braking element relative to the
axis of the wheel. For convenience, any adjuster
for performing the second function is herein des
ignated as a “circumferential adjuster.”
In the embodiment of Figs. 1 to 11, a circumè
ferential adjuster 53, automatically extensible in
response to axial tension, is provided to increase
the effective length of the braking element I8
70
in response to the diametrical adjustments by the
stops 52 so that the range of movement of the
actuator pin 32 will remain constant-regardless
of wear.
75
The adjuster 53 serves as a ñoating
pivotal connection, diametrically opposite the ac
movements are proportional to mass, _the mass of
»the screw members 54 and 56 is kept small, and 60
the lead of the threads 55 and 51 is so correlated
to the- action of the brake 63 that unwarranted
rotation of the member 54 will be prevented with~
out materially reducing the sensitivity and rc».
sponsiveness of the device.
1
A clutch is provided to prevent reverse rotation
cf the screw member 54 when the latter is abut
tingthe stop 59 and the screw device is under
compression~ by reason of the retractile force ofthe band »I8. The clutch may be of any suitable
type and associated with the member 54 in
any desired manner or location, but .prefer
ably ccmprises ‘coacting crown' teeth 6I and 62
(see Fig. 7) respectively on the abutting sur»
4
- faces of -the member and the stop 59. '_I'hus, the
lating material is confined against the outer~ face .
of the, disk 8.3 by an enclosing cap 85 having
In the preferred construction of the radial an end wall 86 in direct bearing engagement with
clearance stop 52, the parts thus far described. ' and conforming generally to the curvaturer of
are mounted in a generally cylindrical radially the inner face of the band I8. .
>
disposed case or shell 63. The inner end of the
By locating the spring 80' outside -of the case
case 63 is securely mounted in an~outwardly open- y 63, a strong spring action for a given radial di
ing recess 64 formed in the flange 42, and closed mension-of the stop 52 can be obtained, and
at its inner end. The recess 64 more particu
the interior of the case need only confine the
10 larly is defined by a tubular radial projection 65
screw-members 54 and 56. Hence, these mem 10
on the outside of the flange 42 and having` an bers may be small in diameter so that their mass
inner end wall 66. The inner `end portion- of will be low, and the axialpitch ofthe threads
the case 63 .is larger in diameter than the outer 55 and 51 in relation to a powerful non-locking
end portion, which is formed internally with lon
lead will be small. ,Because of this relatively
n. . Ul gitudinal splines sli'dably interñtting with' the small axial pitch, rotation of the screw mem 15
splines on the member 56 to complete the spline ber -54 through the distance of one tooth 82 will
connection 56“, and hence defines an annular out
effect but a very small axial adjustment ofl the
wardly facing shoulder 61 at the base of the member 56, and hence a close and accurate com
latter. Two intercommunicating bores 68 and pensation for wear will be obtained.
69 of relatively large andA small diameters open
The clutch teeth 8| and 62 are formed respec 20
respectively through the inner and outer end por
tively on the outer face of the s'top disk 59 and
tions of the case 63, and at their juncture de
the free end of thehead 13, and are annularl'y
ilne the annular inwardly facing stop shoulder arranged about> the axis ofthe member 54. The '
58. The inner end of the bore 68 is closed by a l teeth are iine, short and rugged, and preferably
plate 10 secured within a counterbore 1 I ,- and rest
are _provided in the form of serrations having
ing against the end wall 66.' Secured within the inclined sides of a low angle adapted to 4seek
bore 68 and'against the plate 18, as by means of full engagement, so as ~to retain the member 54
knurls 12 is a circular disk. defining the stop 59, in‘initial position or upon adjustment in an
in axially/.opposed relation to the shoulder- 58. advanced position of one or more teeth securelyï
30 . The inner screw member 54 projects axially against the retractile force of the band I8.- The 30
into the bore 68, and has an enlarged head 13 _height of the teeth 6I and 62 4is less than the
adapted in its innermost position to abut. the permissible extent of movement of the head 18
' >stop 58. Formed in the base end of the head 13 between the shoulder 58 and the stop 59`so'that
about the shank of the screw member: 54 is an the teeth will be disengaged when the ring 15 '
teeth 62 in effect constitute the stop.
_
'
upwardly facing annular _ball _raceway' 14. _ A
ring 15, formed with an opposed raceway 16, en
circlesthe shank, and is adapted for movement
engages the shoulder 58.
,
>
_
When the brake band I8 is in retracted posi
tion, the screw members 54 and 56 as a unit are
" therewith from its innermost position -through a
located in their innermost position. 'I'he clutch
predetermined clearance A_ into engagement teeth 6I and 62 are in full-engagement, and the
with" the operating -stop vshoulder 58. Suitable radial clearance between the drum I5 and the 40
ball bearings 11 are *interposed between and iny band I8 is determined -by the relative adjustment
engagement with the raceways 14 and 1_6. The of the members 54 and 56. Upon applying the.
ring 15-is held in bearing engagement with the brake, the spring 88 causes the screw member
_ balls 11 by a split retainer ring 18 radially over-_ _ 56 to follow the band I8 outwardly. Initially,
45 lapping the ring 15, and sprung into ¿an annular
the screw members 54 and 56 move axially as a 45
groove- 19 in the shank of the screw member 54. unit, andl without being placed under axial stress
It will be evident that the inner screw member 54
is permitted a limited axial movement through
the clearance A between the fixed stop 59 and the
shoulder 58, and that it is freely rotatable when
by the brake applying action. If the outward
movement of the band _I8 does not exceed the
clearance A, the head 13 will be l‘ocated between
the stop 59 and the shoulder 58, and hence no 50
adjustment for ‘wear will be obtained. How
ever, if the outward movement is continued,
in its outermost position.VA
'I'he outer screw member V56 is slidably mount-4
ed in the bore 69, and projects outwardly there _ the bearing ring 15 will engage the shoulder 58
from .for coaction. with the brake` band I 8. In to restrain the inn'er member 54 against further
the preferred construction, _the screw member 56 movement. In this position, the clutch teeth 6I 55
does -not have _a 'direct mechanical connection and 62 are 'fully disengaged. Still further move
with the band I8 so that the latter is free for ment of the outer member 56 willA place the
movement laterally thereof, such as might re
screw device under tensile stress, and thereupon
sult in the application vofthe brake; in circumfer
the screw threads 55 and 51 will effect a rotary
60 ential adjustment for wear, or byreason of a adjustment of the inner member 54 proportion
servo-action, but is caused to follow. the band out .ate to‘_ theA excess movement. Upon the release
wardly under the. iniluence of spring pressure. ofthe brake. the screw device will be returned
When the brake is released, the screw member 56 to’ its innermost position. .If the rotary adjust
' is move'd inwardly by the band I8 in response to ment of the member 54 did not exceed the length
65 the retractile action of the springs 21. More spe-A ' of'. one clutch tooth, the inclined sides of the
ci-flcally, the screw member 56 is urged outwardly vteeth 6I and 62 will rotate the member in -a
“9
by a'. coiled compression spring 80 which loosely -» reverse direction into its original position. If
‘encircles the-outer end_portion of the case 63, the rotary adjustment exceeded the distance of
and `which abuts at its inner end against the one or more of the clutch teeth, the clutch 6 I, 62
shoulder 6_1 and a pair of interñtting concentric will lock the member 54 ina new position. of ad
conical wedge rings 8l seated in an annular notch justment to reduce the' braking clearance of
82 inthe latter. The outer end of the spring 80
abuts against a ilat annular overhanging. disk
83 rigidly secured to the outer end of the screw
member 56. A circular layer 84 4of heat insu
the band I8.>
I
v
“5.
70
»
The brake 60 for holding the screw member
54 against unwarranted rotation when _in sus
pended -position between the'stop 59 and the 75
5
2,106,167
shoulder 58, Vas for example during outward or
inward movement, or while the brake is applied,
phragm 90. An aligned pin |00 has an enlarged
head engaging the other side of the diaphragm 9_0,
is provided in the form of a semi-circular com
and extends slidably through an axial bore |0| in- `
pression bow spring mounted within a tubular
the stop disk 59 for engagement with the end of
the screw member 54. Thepin 91 is rounded at
i extension 59a of the stop 59. The extension 591L
projects into an axial bore 81 in the free end of
the head 13. The spring A60 has radial ends 88
which extend slidably through slots 89 in the
peripheral wall of the extension 59a into fric
10 tional end engagement with the surface of the
bore 81. The braking action of the spring ends
88 is suñiciently strong to' prevent rotation of
the member 54 by reason of the weight of the
parts, vibration, momentum or other outside in#
15 fiuence to'which the self-,adjusting -device may
be subjected, _particularly- on motor vehicles,
but is so correlated to the lead of the threads
55 and 51 and the mass of the parts that it will
its inner end for cam engagement with a release
plunger |02 manually slidable in the bore 98.
Formed in the stop disk 59 about the pin `|00 is
a circular recess_|03 permitting flexing of the
diaphragm 90 away from the plate 10. A spring
spider |04, mounted under `compression within
the recess |03, engages the head of _the pin- |00,
and tends to urge the assembly ofthe pins 91
and |00 and the diaphragm 90 into inoperative
position for actuation by the plunger |02.
vNormally the diaphragm 90 rests against the
outer face of the end plate 10 which serves as a
‘solid reinforcement vto protect the diaphragm
from the pressure of gases likely lto exist within
the case 63, and which preferably is dish-shaped 20
To prevent impairment of the eiìciency and ' so ,that the diaphragm willbe-subjected to _the
permit sensitive and accurate adjustment for
20
wear.
~
life of thel device by reason of the deleterious
effect of grit, dirt, water and other foreign mat
ter, and the loss of proper lubrication, the self
25 adjusting parts are enclosed in an hermetically
sealed space. In the present instance, the inner
end of the case 63 is sealed by a diaphragm 90
clamped against the end shoulder of the counter
bore 1| «and the stop disk 59 by the end plate
30 10 with suflicient force to obtain a tight j_oint,
and the outer end is sealed from _the atmosphere
by a corrugated cylindrical bellows 9| concen
tricallyencircling the spring 80 and having a
tight connection at its ends respectively with
35 the exterior of the case at the shoulder 61 and
the disk 83. The inner end of the bellows 9|`
Yis tightly secured between the inner and outer
conical wedge surfac'ës of the two clamp rings
8|. The outer end of the bellows 9| is similarly secured between the disk 93 and an encircling
wedge clamp ring 92. The bel1ows9| is formed
with small deep convolutions and is made of a
light thin material so as to be readily extensible
through the desired range of adjustment With
out undue deformation, and to permit free and
45 substantially'unrestrained
operation of the self
adjusting device.
«
The longitudinal spline connection 56a is pro-A
vided between the case 63 and the screw «mem
50 ber 56 toI hold the latter against rotation. It is
î to be noted, however, that the bellows 9| will
resist such rotation.
.
Preferably, the bellows 9| is enclosed in an
outer housing which comprises telescoping cy
.55 lindrical shells 93 and 94, and which affords
protection against mechanical injury and pre
vents the accumulation of dirt and other foreign
matter. The shell 93 has an inner peripheral
flange 95 secured in the notch 82, between the
60 case 63 and the rings 8|, and lencircles the inner
end portion of the bellows 9|. The outer shell
» .94 is formed by extending'the cylindrical wall
of the cap 85. A stop ring 96 is secured within
the free end of the shell 94, and is adapted for
engagement with the ñange 95 to limit the maxi
mum> outward _adjustment of the member 56.
` The screw device 54, 56 is adjusted progressive
ly to compensate for wear on theA brake lining I9.
' When the lining |9 is replaced, the device isrreset
into its initial position. To permit such resetting
least possible strain in its movement from one
extreme position to the other. When it is de
sired to reset the'device 54, 56, 4the plunger |02
is moved inwardly, thereby acting through the .25
pin 91 and the diaphragm 90 to move the pin |00 ‘
radially outwardly-against the action of the _spring
|04 to lift the head 13 out~ of clutch-'engagement
with the stop 59, without interrupting the her
metic seal.
The side of the plunger |02~serves 30
to lock the pin 91.in adjusted position (see Fig. 5).
Thereupon, the outer screw member 56`> can -be
forced .inwardly to effect reverse rotation of the
inner screw member 54 to the desired extent. _'For
convenience in assembly. the screw member 56 85
may be locked in fully retracted position." Tothis end, the shel1>94 is formed with an'opening
|05 adapted to be moved into registration with a
recess |06 in the side of thel case ~63 for the'
insertion of a pin or other locking tool (not
shown). When the assemblyis completed, the
locking pin is- removed,‘and the plunger |02 is
withdrawn from the .pin 91. Thereupon, the de
vicel 54, 56 will adjust itself to define the properv _
radial clearance A.
'_45
For eñicient and reliable operation, the f-ree
acting characteristics of the bearing surfaces of
the radial clearance adjuster 52- should be-pi‘e-served by proper lubrication and protection from
the grit, dirt, moisture and 4other foreign matter 50
which is likely to -be present in the brake. If
the interior of the~ adjuster Were'exposedfto the
atmosphere.. even through a comparatively small
vent, foreign matter might find its way between
the ,bearing surfaces, and breathing would be 55
permitted. Lubricant would be lost, and moisture
or humidityv entering with the air would be likely
to. cause corrosion. The relatively high tempera
tures resulting on occasion from the Vbraking ac
tion would cause oxidation and sludgîng of the
lubricant inthe presence of the oxygen of the
air. All these difllculties are definitely avoided
by the hermetic seal provided by the diaphragm
90 and the. bellows 9|.
__
.The circumferential adjuster 53 is similar in 65
construction and mode of operation tothe radial
clearance stops l52, but by reason of its‘ specific
location and manner of association with* the
sections of ‘he band I8 hasa different function.
Thus, the adjuster 53 is adapted to elongate'free-` 70
ly when the brake is released'in response to axial
without breaking the hermetic- seal, a pin 91 e;
tends slidably from a transverse bore 98 in the stress which will be set up >as a result of outward
wall 66 through a series fof aligned axial bores' ‘ adjustment of the radial stops 52, and will- prevent'
99. formed respectively in-the Wall and the plate shortening of the -band assembly whenthebrake
is applied. The primary function of the cir 75
75 10 into engagement with one side of the dia
_
6
2,106,137
cumferential adjuster 53 may be said, therefore, A» and |08'.v The ends of the bellows |43 are tightly
to maintain automatically- the proper length of
the braking element I8 so that the 'range and
phase of movement of the actuator 32 will re
main constant, and that in the particular type
of brake herein disclosed the band ends 24 and
25 in idle position will always engage the abut
-ment 26, regardless of radial adjustment for
In its preferred form, the circumferential ad
juster 53 comprises two elongated cylindrical
sleeves |01 and |08 which telescope for relative
axial adjustment, and which' are pivotally con-nected at their remote ends «to brackets |09 and
I I0 secured to the adjacent ends I8a and I8b of the
separated Asections'of the lband I8. Preferably,
the brackets |09 and ||0`are U-shaped in form
with inwardly extending parallel walls |I| and
I I2 respectively which extend along opposite sides
20 of the adjuster 53. In the present instance, the
vpivoted end of the outer sleeve |01, which in eiîect
constitutes the case of the adjuster 53, is closed
clamped between two sets of concentric rings |44
and | 45 respectively pressed onto the base ends
of the sleeves |01 and |08. Enclosing the bellows|43 is an outer housing comprising "two telescop
ing cylindrical shells |46 and |41.
The inner ‘
shell |46 at one end is connected to the outer
ring |44,- and at the other end has an outer
peripheral flange |48. The outer shell |41 at one
end is secured to the outer ring |45, and at its 10
free end has an inner peripheral ñange |49. The
flanges |48 and |49 are adapted'for engagement
to limit the maximum` elongation _of the ad-v
juster 53. The hermetic seal has the same func
tions and advantages as in the radial adjust 15
ers
52.
_
«
`
- The clutch teeth |28 and Ä| 30 may be held out
of engagement by a pin |50 which has an en
larged head |5I bearing against the inner face
of the diaphragm |42, and which extends slid 20
ably through a series of axial bores |52 in the
plate |26 and the clutch .disk |21 into an axial
‘ by an end Wall I I3, and is formed with a trans
bore |53 in the end/of the head |29. _ A recess |54verse bearing sleeve |I4 rotatably confined be- - is formed in the outer face of the plate |26 about
tween the walls III on a headed pivot bolt |I5.
Similarly, the pivoted end of the inner sleeve |08 is closed, and is formed with a _transverse bear
ing sleeve I I6 rotatably conñned between the walls
I|2 o'n a pivot pin II1. .Suitable cotter pins ||8'_
30 are provided for holding the bolt |`|5 _and the pin
|I1 in axial position in the Vbracket walls III. "
and II2. To provide means for normally hold ,
ing the bolt | I5 against rotation, it is formed- with
the pin |50 to permit flexure` of the diaphragm
|42 from the -dish-'shaped _backing face of the
wall I_I3 against which it is normally positioned.
Extending slidably 'from _the sleeve ||4'through~
a bore |55 in the wall I|3 into engagement with
the outer Iface of the diaphragm |42 is a headed 80
pin |56 in axial alignment with the pin |50. lThe .
outer- end of the pin |56 is rounded for engage
ment with a transverse cam face |51 on the bolt
a transverse bore ||9 whichis ladaptedto be 'lo- _ ' ||5. A compression spring spider |58 is mount-'
35 .cated in registration with a bore |20 in one of the ed in the recess |54 in engagement with, the 35
walls |.|| for the reception of a removable lock
ing pin |2I.
_
‘ ‘
head |5I, and tends to retract the pin |50 from
' '
The sleeve |08 is formed in its free end with the head |29. ‘
In operation, when the brake is released, the
:Internal screw threads |22 in coacting engage
ends 24 'and 25A are held against the abutment 26
ment with screw threads |23 on one end of a ro-'
tatable member |24 extending axially therefrom. by the retractile springs 21, and the sections of the
The threads |22 >and |23 >have a- steep non-locking band |.8 are positioned against the radial stops 52
and have a predetermined clearance A with the
lead. The sleeve |08 and the member _|24 there - drum.the brake is applied, the circum
fore are relatively rotatable when subjected to ferentialWhen
adjuster 53 is placed under compression,
axial
stress,
and
constitute
a
self-adjustable
45
thereby causing the clutch -teeth |28 and |30_to- 45
screw device.
.
`.
‘
_
_ Rigidly secured in the- closed end of the sleeve
|01, as by means of knurls |25, is a~ñxed plate
|26. A stop |21 ,is'mounted' in-l the sleeve |01
50 against the plate |26, and formed on its exposed
face with an annular series of clutch teeth |528.
The adjacent end of the screw member |24 has an
enlwarged head |29 formed on its free end with an
ss
lock the screw member |24 against rotation, and '
the band |8_is expanded into engagement with ‘
the drum I5., If the clearance is enlarged by
reason of wear on'the lining _|9, the stops 52
will eifect a compensatory adjustment, as the 50
b_rake is applied, thereby enlarging the effective
diameter of the band I8. Upon subsequently re
leasing the brake, the springs 21 will- return the
annular series of clutch teeth |30 adapted to
coact with the .teeth |28. A plurality of ball , ends 24 and 25 against the abutment 26, and will
cause the band sections through coaction with
bearings |3I Vare confined between annular'op
-the
stops 52 to elongate the circumferential ad
posed raceways _|32 and |33 formed respectivelyA
in the other end of the head |29 and a ring juster 53 against the action of the springs |40.
|34 encircling the screw member |24. The ring ' If the ~elongation is in excess of the distance
|34 is held in position by a split band |35 seated necessary'to bring the bearing ring |34 into en
in a. peripheral groove |36, and is adapted for gagement with the shoulder |31, the clutch teeth
|28 and |30 will be separated, and axial stress
movement. into'engagement with a shoulder |31
defined by a stop ring|38 secured in an inner will be placed on the threads |22 and |23 to
peripheral groove |39 in the sleeve |01. Two effect rotation ofthe screw member |24 and ¿»
coiled tension springs I40,_anchored at their ends - thereby to increase the length of the brake band 65
to laterally extending Alugs |4| respectively on
theside walls III and ||2 ofthe brackets |09
and ||0, tend to contract _the adjuster 53, and
assembly.
Y
_ To reset the adjuster 53` when the lining I9 is
replaced, the pin |2| is removed, and then the
to hold the teeth lI 30 and |3| in clutch engage- . bolt ||5 is rotated to urge the pin |50 against
ment. These springs have> a lower tensile
strength than the brake retracting springs 21.
To'provide an hermetic seal,.a diaphragm |42
is clamped between the end wall |»|3 of the
` ' sleeve |01 and the plate |26, and a corrugated
75 cylindrical bellows |43 encloses the sleeves |01
the head |29, thereby opening the clutch |28, |30 70
and permitting reverse adjustment of the screw
device by axial compression.
The same result _
may be obtained, with the _pin |2| in position, by .
turning the adjuster 53 on the bolt |'I5 rela
tively to the band end I8“,75
7
2,106,167
As in the radial -stops 52, the weight of the
moving parts, vibrations and particularly sharp
exceeds a predetermined value, the,l springs |40
being provided with sufficient strength to counter
up and down accelerations of- the wheel, unless
rendered ineffective, are likely to effect misad
a
act the extending force resulting from any
justments of the circumferential adjuster 53.
Misadjustments of the screw member |24 due to
its own mass are prevented by a brake |59, simi
lar to the brake 60. The brake |59 consists of a
8
below such value. -Thus, the clutch disk |21 is
axially slidable on the pin |50, and is held against
in any axial position by a tongue |63
compression bow spring which is disposed in a ' rotation
(see Fig. 1l) on Aone end slidably disposed in a 10
10 tubular extension |21n on the clutch .disk |21 and notch |64 in the end plate |26. A coiled spring
projecting into a recess |60 in the free end of
|65, encircling the pin |50, is interposed under
the head |29, and whichl has outwardly bent ends compression between the head |29 and the disk
|6| extending slidably through slots |62 into |21, and normally serves to hold the latter against>
frictional engagement with the inner peripheral
15 surface of the recess |60.
Acceleration of the wheel acting on the mass
of the parts, for example the sections of the band
i8, to which the circumferential adjuster 53 is
directly attached are likely under certain con
20 ditions to subject the adjuster to very heavy ex- .
tending forces. The circumferential adjuster 53
is most conveniently located in a vertical posi
tion diametrically opposite the actuator 32. If
the wheel when traveling rapidly strikes a bump
25 in the road, it will be thrown upwardly violently .
with a high acceleration.
Thereafter, a down
ward acceleration of substantially equal value
will obtain. The downward acceleration may be
expressed by the following equation:
30
a=éX à), where Y".
the plate |26.
If the
a
vexceeds a value determined by the pressure of the
spring |65, the clutch disk |21 will leave the plate 20
|26 under the influence of momentum, and fol
low up the head |29 to prevent separation of the
clutch teeth |28 and |30, thereby- locking the
screw member |24 against rotation. Preferably,
the clutch teeth |28 and |30 in this instance are
crown ratchet teeth which will not tend to sepa-
rate through mutual coaction when. the screw
member |24 is subjected to axial tension.
In the modified form of the invention illus
trated in Figs. 12 to 14, the radial and circum 30
ferential self-adjusters for carrying out functions
one and two hereinbefore defined, are suitably
embodied in a mechanically operable internal
g=gravity,
L=the load placed on the wheel axle by the
spring, _and
-
W=the weight ofk the' wheel and axle and of the
parts thereon.
The ratio of this acceleration to gravity, con
veniently representedv by the symbol
40
multiple»shoe brake. The brake comprises a ro
tatable drum |5a, and a fixed support 4| a therein. 35
Two -ribbed arcuate shoes |8c and I8d are pivot
ally anchored on the support 4|a, and are faced
with a suitable brake lining I0a engageable with
the drum |5a. Coiled tension springs 21a
anchored to the support 4|a tend to retract the
shoes.
'
15
`
g
.
The free ends of the shoes 18" and »|8d have
oppositely acting crank connections with a rock
e
l
may far exceed 1.- Thus, if the weight of the
parts is taken as 1000 pounds, and the load on
the axle exclusive of the weight should be 5000
shaft |61 rotatable in a bearing |68 onthe sup
port 4in. Connected to the shaft |61 is an
pounds, the
the retractile force of a spring |10 by a pull rod
|1| to apply the brake. A notch |12 in the shaft
|61 is engageable with a pin |13 on the support
4|a to limit. the retractile movement of the actu 50
ator. Two -stops 52?- are- pivctally connected by
y
MHD
would equal 5.
Any tension set up by the
â
will tend to elongate vthe adjuster 53, and, unless
counteracted, would be likely to overadjust the
length of the braking element assembly, even to
the extent of locking the band I8 against the
drum |5 when the brake is released. Such eX
tending force is fully counteracted by providing
60
the springs |40 with sufficient strength. The
springs |40, being weaker than the springs 21,
however, will not prevent normal operation of
the adjuster 53 in response to release of the brake.
A similar problem does not arise in the radial
adjusters 52, since the function of the latter is
to follow the band I0 outwardly against the drum
l5, and since the lost motion for the screw mem
ber 54 will always provide the desired radial
clearance A when the band is retracted by the
operating lever |69 adapted to be actuated against
means of pins 4|b at opposite ends respectively to
the support 4|a and the associated brake shoes
i0c and |8d, and are automatically extensible
in response to axial tension to maintain a pre 55
determined braking clearance A regardless of
wear on the lining |93.. By reason of the direct '
or positive connections with the shoes by reason'
of the pins 4|b,. the stops 52a need not comprise..A .
extending springs, corresponding to the springs 80.- 60
_Each of the adjusters 52a is liketheîîcircum
ferential adjuster illustrated in Fig.¿_£4lA except for
the location of the pivotal connectió?g-¿â'oy means
of the pins 41h instead of the pins H5 and ||1
and except for the substitution of the springs |40 65
by the |springs 21a and connection of the latter
to the ends of the pins Mb, and hence the corre
sponding parts are identified by the same ref
erence numerals plus the distinguishing letter a.
Referring to Fig. 15, the transverse bearing sleeves 70
70 springs 21.
. |54a and H5a are disposed respectively between
,
As an -alternative measure, the adjuster 53 may spaced lugs |16 rigid on the support or spider 4|“
be self-locking to prevent adjustment if the
'and between the webs | l2“ on the free end of the
a.
isl
8
shoe I0“, and are pivotally connected thereto by
the pins 4|". .
`
_
76
8
2,106,167
Two circumferential adjusters 53”L are inter
posed respectively in the connections between the
free operative ends of the shoes I8c and I8d and
the rock shaft |61. Each of the adjusters 538L is
combination, a self-adjusting unithaving two
relatively rotatable screw members withV non
locking coacting threads and being adjustable
in axial length through relative rotation in one
automatically extensible in response to axial ten- ~ direction when subjected to an axial force'in one
sion, and is provided at opposite ends with round
direction, and an hermetically sealed housing en
- ed portions |14 pivotally secured respectively in closing the bearing surfaces of said unit and
sockets |15 in the end of the associated shoe and including a yieldable corrugated cylindrical bel
the side of the shaft |61. . Each of the sockets |15
. 1.0
has a restricted opening less in width than the
diameter of the associated portion |14 so that the
latter cannot be removed from the socket when
subjected to a pull transversely> of the shaft |61.
The parts are adapted to be assembled by moving
lows.
3. A wear compensating device for main‘ain
ing~ a predetermined operating slack comprising,
10
in combination, means defining an idle rest stop
and a spaced opposed operatingstop, _a self-ad
justing unit having two relatively rotatable screw
the rounded portions |14 axially of the shaft |61 members with non-locking coacting threads and
into the sockets |15. 'I'he two sockets |15 in _the ~having a lost motion between said stops and being
shaft |61 are located at opposite sides of the axis. adjustable in axial length- through relative ro
Referring to Fig. 16, each of-the adjusters 53a, tation in one direction wh'en subjected to an axial
except :for the character of the pivotal connections force inonevdirection while against said operat
just described and except for the elimination of ing stop, and clut'ch means adapted to be opened 20
springscorresponding to the springs |40, .also in and closed upon movement of said unit reversely
like the _circumferential adjuster Aillustrated in through said lost motion, and being operable to
Fig. 8, and corresponding parts a_re therefore iden
tiiled by the same reference numerals plus the
distinguishing letter b. It will be understood
that the rounded portions |14 are integral re
prevent relative rotation of said members in a re
verse direction when said unit is located against
said rest stop, said clutch means comprising short
V-shaped teeth projecting axially of said unit
spectively with the outer closed ends of -the sleeves j and arranged in two coacting sets annularly and
‘ |01” and |081’. Since pivot pins are -not em
concentrically about the axis of said unit.
ployed, access to the pin »|56b is obtained through
by means of the pins 4| b to the support 4| ß and
4. _A wear compensating device for maintain
ing a predetermined operating slack comprising,
in combination, means deñning an idle rest stop
and a spaced opposed operating stop, a self-ad
the shoes I 8° and ltd, serve-the dual function of
retracting the shoes I8° and I8d when the brake
is released, and of resisting elongation of the
screw members with non-locking coacting threads
and having a lost motion between said stops and
. a transverse bore |11.
It will be evident that the
springs 211, which are anchored at opposite ends
adjusters 53‘, thereby obviating the necessity for
other springs corresponding to the springs |40.
The springs 2'_|l are of suiiìcient strength to pre
vent overadjustment in response to any
40
a
é
.
likely to arise, and hence the .adjusters 53a are
- not self-locking.
In all otherl material respects,
the adjusters 53a are substantially the same in
construction and operation as the adjuster 53.
The circumferential adjusters 53a will elongate
automatically, as necessitated by elongation of
the stops 52a, to permit the notch |12 always to
return to the pin |13 in the release movement of
the brake, and hence serve in effect to lengthen
the shoe assembly so as to maintain constant
the extent and phase of rotation of the actuator
shaft |61.- Thus, foreshortening of the moment
arm of the actuator is prevented.
’
justing unit having two relatively rotatable
being adjustable in axial length through relative
rotation in one direction when subjected to an
axial force' in one direction while against said
operating stop, and clutch means adapted to be
opened and closed upon movement of said unit 40
reversely through said lost motion, and being
operable to prevent relative rotation of said
members in a reverse direction when said unit
is located against said rest stop, and means
available at will for opening said clutch mean 45
to permit manual resetting of said unit.
'
'
5. A wear compensating device for maintaining
a predetermined operating slack comprising, in
combination, means defining an idle rest stop
and a spaced opposed operating stop, a self-ad
justing unit having two relatively rotatable
screw members with non-locking coacting threads
and havinga lost motion between said stops and
being adjustable in axial length through relative
rotation in one direction when subjected to an 55
axial force in one direction while against said
In all of the adjusters described, the advan
tages and 'purpose of the low pitch -of the screwA operating stop, and .clutch means adapted to be
and closed upon movement of said unit
threads,- the hermetic seal, and other features opened
reversely through said lost motion, and being
common
thereto
are
the
same
as
those
in
the
60
operable to prevent relative rotation of said mem
adjusters 52.
I claim as my invention:
l
1. A wear compensating device for maintain
ing a predetermined operating slack comprising.
in combination, a self-adjusting unit having two
relatively rotatable screw membersA with non
locking‘coacting threads and being adjustable in
axial length through relative rotation in one di
rection when subjected to an axial force in one
70 direction, and a housing enclosing said unit and
being hermetically sealed to prevent the loss or
deterioration of lubricant and the entry of foreign
Y
matter.
~
-
2. A wear compensating device for maintaining
a predetermined operating slack comprising, in
bers in a reverse direction when said unit is
located against said rest stop, means for enclos
ing the bearing surfaces of said unit and said
clutch means in an hermetically sealed space.
and means available at will for opening said
clutch means to permit resetting of said'unit
without breaking the hermetic seal.
6. A wear compensating device for maintain
ing a predetermined operating slack comprising,
in combination, an elongated tubular case closed 70
at one end, an end face clutch element in said
closed end, a unit having a non-rotatable `screw
member projecting from the other end of said
case and having a second screw member rotatable
in said case to adjust the length of said unit,
2,106,161 y
an end face clutch element on 'said rotatable
member for coacting with said ñrst mentioned
element to prevent rotation in one direction, and
'manually operable means for separating said
clutch elements.
7. A wear compensating device for maintain
ing a predetermined operating slack comprising,
in combination, an elongated tubular case closed
at one end, an end face clutch element in said
10 closed end, a unit having a non-rotatable screw
member projecting from the other end of said
case and having a second ~screw member adapted
9
f
and for rotation to eii'ect axial adjustment of
said iirst mentioned member, an end face clutch
element on said rotatable member for coacting
with said first mentioned element, a yieldable bel- -
lows providing an hermetic seal between said case
and the projecting end of said non-rotatable
member, a pin movable with said diaphragm and
adapted for end engagement with said rotatable
member to separate said clutch elements, and
means for flexing said diaphragm'.
11. A wear compensating device for maintain
ing a predetermined operating slack comprising,
for limited axial movement in said case _and for»
rotation to eiîect axial adjustment of said ñrst
mentioned member, an end face clutch element
on said rotatable member for coacting with said
in combination, an elongated case closed at one
end and defining an inwardly facing annular
shoulder, a rotatable screw member having an 15
enlarged head adapted for engagement with said
first mentioned element, a yieldable diaphragm
hermetically sealing the closed end of said case,
a pin movable with said diaphragm and adapted
threaded engagement with said rotatable mem
20 for "end engagement with said rotatable mem
ber to separate said clutch elements, and means
for flexing said diaphragm.
„
shoulder,
a non-rotatable screw member in
ber and projecting from said case, said members
being adapted for relative rotation when subject
ed to axial'force in one direction, and a corru
20v
gated axially extensible and contractible general
ly cylindrical bellows having an air-tight seal at
ing a predetermined operating slack comprising, » its ends respectively with the exterior of said case l,
in combination, an elongatedtubular case closed and the projected end of said non-rotatable 25
8. A wear compensating device for maintain
at one end, an end face clutch element in said
closed end, a’ unit having a non-rotatable screw
member projecting from the other end of said
case and having a second screw member adapted
30
for limited axial movement in said case and `for
rotation to eii’ect axial adjustment of said first
mentioned member, an end face clutch element
on said rotatable member for coacting with said
ñrst mentioned element, a yieldable diaphragm
$3 LI hermetically sealing the closed end of said case,
a pin seated against one side of said diaphragm
and adapted to be moved thereby into axial en
[agement with said rotatable member to separate
said-clutch elements, a pin extending through
40 said closed end of said case into engagement with
the other side of said diaphragm, and a trans
versely adjustable cam plunger adapted for en
gagement with said last mentioned pin to actu
ate the latter against said diaphragm and to
lock the latter in actuated position. - '
9. A wear compensating device for maintaining
a predetermined‘operating slack comprising, in
combination, an elongated case closed at one end,
a positive end face clutch element in said closed
50 end, a. unit having- a non-rotatable screw mem
ber projecting from the other end of said case
and having a second screw member adapted for
limited axial movement in said case and for
u Si
rotation to eiîect axial adjustment of said ñrst
mentioned member, a positive end face clutch
elementen said rotatable member for coacting
with .said firsty mentioned element, a yieldable
diaphragm -hermetically sealing the closed end
of said case, a pin seated against one side of said
60
m'ember.
`
12. In a brake, in combination with a station- '
ary support,l a drum and a friction element en
gageable with said drum, a. radial clearance stop
for said element comprising'a case mounted on
said support and deñning a. rest stop and a spaced
opposed operating stop, two relatively rotatable
screw members constituting an adjusting unit
and having non-locking coacting threads, one of
said members being non-rotatable and axially 35
movable with said element, the other of said
members having a limited axial movement'with
said one member through a limited clearance
from said rest stop into engagement with said '
operating stop, and then being rotatable against 40
said operating _stop by reason of the coaction of
said threads to eiîect an elongation of said unit,`
clutch means for preventing rotation of said other
member when in retracted position against said
rest stop, and brake means for frlctionally resist 45
ing yrotation of said other' member. '
. .
13. In a brake, in combination with a statibn
ary support, a drum and a friction element en
, gageable with saiddrum, a radial clearance stop
for said element comprising two relatively rotat 50
able screw members having non-locking coacting
threads, one of said members being axially mov
able with said element from an idle position ñrst
through. a predetermined clearance and then to
effect relative rotation between said members by 55
reason of the coaction of said threads and thereby
to effect an elongation of said stop, fixed means
for defining said idle position, and brake means
for resisting said relative rotation.
.
14. In a brake, in combination with a station 60
diaphragm and adapted to be moved _thereby into
axial engagement with said rotatable member to ary support, a drum and a friction element en
separate said clutch elements, a pin extending gageable with said drum, a radial clearance stop
through said closed end of said case into en - for said element comprising two relatively rotat
gagement with the other side of said diaphragm, able screw members having non-locking coacting
and a relatively rotatable cam for actuating said _ threads, one of said members being axially mov 65.
able with said element from an idlev position ñrst
last mentioned pin against said diaphragm.
through a predetermined clearance and then to
10. A wear compensating device for maintain
ing a predetermined operating slack comprising, ' effect relative rotation between said members by
in combination, an elongated peripherally closed- reason of the coaction of said threads and thereby
case, a yieldable diaphragm hermetically closing to effect an elongation of said stop, fixed means 70
one end of said case, an end face clutch element for deñning said idle position, clutch means for
in said closed end, a unit having a non-rotatable
screw member projecting from the other end of
preventing relative rotation of saidv members „
when said one member is in idle position, and
said case and having a second screw member friction means for resisting said relative rotation '
adapted
for limited axial movement in said case , when said clutch means is open.
75
10
2,106,167
15. In a brake, in combination with a station
ary support, a drum and a friction element en
movement of said unit from said retracted posi
tion through a predetermined limited distance,
gageable with said drum, a radial clearance stop
for said element comprising two relatively rotat
able screw members having non-locking coacting
brake means resisting rotation of said other
member, and clutch means for preventing rotation
of said rotatable member to prevent axial con
traction of said unit when in retracted position.
threads, one of said members'being axially mov
able with said element from an idle position iirst
through a `predetermined clearance and then to
eiïect relative rotation between said members by
10 reason of the coaction of said threads and there
by to effect an elongation of said stop, ñxed m‘eans
for defining said idle position, and means for
hermetically sealing said threads within an
ment of saidelement and comprising a case mount
ed on said support and defining opposed fixed
stops, two screw members having non-locking co
erally radially of said band, two screw members
having‘non-locking coacting threads and consti
tuting a self-adjustable unit movably disposed in
acting threads and constituting a self-adjustable
unit movably disposed in said case for engage 15
ment in retracted position against one of said
stops, one of said members being non-rotatable
and having an end projecting from said case for
movement with said element, the other of said
members being rotatable and adapted for engage 20
ment with the other of said stops upon movement
of said unit from said retracted position through
a predetermined limited distance and being
said case for engagement in retracted position
formed with a central recess, a bow compression
enclosed space.
15
19. In a brake, in combination with a sta
tionary support, a brake drum, and a friction
element engageable with said drum, a radial
clearance device for limiting the retractile move 10
-
v
16. In a brake, in combination with a station
ary support, a brake drum, and a friction element
engageable with said drum, a radial clearance de
vice for limiting the retractile movement of said
element and comprising a case mounted on said
20 support and deñning opposed stops spaced gen-.
25 against one of said stops, one of. said memibers
being non-rotatable and having an end projecting
from said case for movement with said element,
the other of said members being rotatable and
having an end thrust anti-friction bearing adapt
30 ed for engagement with the other of said stops
upon movement of said unit from said retracted
position through a predetermined limited dis
tance, and clutch means for preventing rotation
of said rotatable member to prevent axial con
35 traction of said unit when in retracted position.
\ 17. In a brake, in combination with a station
ary support, a brake drum, and a friction element
engageable with said drum, a radial clearance de
vice for hunting the retractile movement of said
element and comprising a case mounted on said
spring mounted on satieSLgne stop and disposed in
said recess and having freeV ends extending into
frictional engagement with the inner peripheral
surface of said recess to brake the rotation of said
other member, and clutch means for preventing
rotation of said rotatable member to prevent 30
axial contraction of said_ unit when in retracted
position.
.
,
20. In a brake, in combination with a sta
tionary support, a brake drum, and a friction ele
. ment engageable with'said drum, a radial clear
35
ance device for limiting the retractile movement
of said element and comprising a case mounted
on said support and defining opposed stops spaced
generally radially of -said band, two screw mem
bers having non-locking» coacting threads and
support and defining opposed stops spaced gen
erally radially oi' said band, two concentric screw
members having non-locking coacting threads
constituting a self-adjustable unit movably dis
posed in said case for engagement in retracted
position against one -of said stops, one of said
and constituting a self-adjustable unit movably. members being' non-rotatable and having an end
45 disposed in said case for engagement in retracted projecting from said case for movement with said
position against one of said stops, the outer mem
element, the other of said members being rotatable
and adapted for engagement with the other of
ber being non-rotatable and having an end pro
jecting slidably from said case for movement with said stops upon movement ,of said unit from said
said element, the inner member being rotatable retracted position through a predetermined limit
and having an enlarged head adapted for end ed distance, clutch means‘for 'preventing rota
bearing engagement with the other of said stops tion of said rotatable member 'to prevent axial
upon movement of said unit from said retracted contraction of said unit‘when in retracted posi
position through a predetermined limited dis
tion, a coiled compression spring encircling said
tance, and clutch'means for preventing rotation case and acting to urge the projected end of said
non-rotatable member against said element, and .
55 of said rotatable member to prevent axial con
traction of said unitwhen in retracted position. a corrugated cylindrical bellows encircling said
spring and having a tight connection at its ends
18. In a brake, in combination with a sta
respectively with said case and the projected end
tionary support, a brake drum, and a friction ele
of said non-rotatable member.
ment engageable with said drum, a radial clear
ance devicefor limiting the retractile movement
21. In a brake, in combination with a stationary
lof said element and comprising a case mounted on
support, a brake drum, and a friction element en
said support and deñning opposed stops spaced
generally radially of said band, two concentric
screw members having non-locking coacting
vice for limiting the retractile movement of said
threads of a high lead and relatively low pitch
support deñning opposed stops spaced generally
and constituting‘a self-adjustable unit movably
radially of said band, two screw members having
non-locking coacting threads and constituting a
self-adjustable unit movably disposed in said case
for'engagernent in retracted position against one
disposed in the center of said case for engagement
in retracted position against one of said stops, one
of said members being non-rotatable and having
70 an end projecting from said case for movement
with said element, acoiled compression spring
outside of said unit for urging said one member
into engagement with said element, the other of
said members being rotatable and adapted for
75 engagement with the other -of said stops upon
gageabie with said drum, a radial clearance de
element and comprising a case mounted on said
of said stops, one of said members being non 70
rotatable and having an end projecting from said
case for movement with said element, the other
of said members being rotatable and adapted for
engagement with the other of said stops upon
movement of said unit from said retracted posi
_
_
_
said drum, said mechanism including a self-ad
justable movement limiting device comprising a
tion through a predetermined limited distance,
clutch means for preventing rotation of said ro
tatable member to prevent axial contraction of
said unit when in retracted position, a coiled com
case, a member rotatable in said case and con
iined against substantial axial movement, a non
rotatable member axially slidable in said case,
pression spring encircling said case and acting to
urge the projected end of said non-rotatable
member against said element, a corrugated cylin~
drical bellows encircling said spring and having a
tight connection at its ends respectively with said
case and the projected end of said non-rotatable
member, a cap positioned over said projected end
said members having non-locking coacting
threads of a relatively high lead and low pitch
and constituting a unit adjustable in length in re
sponse to an axial force in one direction, and
brake means for resisting rotation of said iìrst
mentioned member.
'
«
v
27. A vehicle brake comprising, in combina
and having a cylindrical sleeve enclosing said
bellows, and means coacting with said sleeve to
limitthe outward movement of said non-rotatable
member.
11
2,106,167
tion, a rotatable drum and a braking mechanism '
for said drum, said mechanism including a-‘self-`
adjustable movement limiting device comprising
.
a case, a member rotatable in'said case and con
22. In a brake, in combination with a sta
tionary support, a brake drum, and a friction
ñned against substantial axial movement, a non
`rotatable member axially slidable in said case.
said members- having non-locking coacting
threads of a relatively high lead and low pitch 20,
and constituting a unit adjustable in length in
element engageable with- said drum,-a radial
clearance device for limiting the retractile move
l20 ment of said element and comprising a case
mounted on said support and deñning opposed
stops spaced generally radially of said band, two
screw members having non-locking coacting
threads and constituting a self-adjustable unit
response to an axial force in one direction, and
means automatically operable inresponse to a
predetermined momentum to. lock said unit
movably disposed in said case for engagement in
retracted position against one of said stops, one
of said members being non-rotatable and having
against adjustment.
-
28. A vehicle`brake comprising, in combina
tion, a rotatable drum, a 4brake element engage
able with said drum, spring means for retracting
said element-from said drum and a stop device
an end projecting from said case for movement
with said element, the other of said members be
30 ing rotatable and adapted for engagement with associated with said element to limit the move
the other of said stops upon movement vof said ment thereof in >one direction, said device com«
unit from said retracted position through a pre > prising a self-adjustable unit having'two rela
determined limited distance, clutch means for. tively rotatable screw members with non-locking
preventing rotation of said rotatable member to l coacting threads and being adjustable in length
When subject to axial tension, and spring means 35
retracted position, brake means for resisting »ro ' other than said first mentioned spring means
tation of said rotatable member, a Acylindrical for placing said unit under compression and-of a
shell movable with said non-rotatable member strength sufñcient to counteract a downward 'ac
35 prevent axial contraction of said unit when in
celeration of said brake bearing a ratio to gravity,
up to 'iive to prevent adjustment in response to 40
and enclosing the outer end of said case, an inner
shell telescoping~ with the free end of said first
mentioned shell and adapted to coact therewith
' momentum.
to limit the. outward movement of said non- -
rotatable member, and means for locking said
outer shell in retracted position.
45
»
29. A vehicle brake comprising, in combination,
a rotatable drum, a brake element engageable
'with said drum, spring means tending to retract
23. A vehicle brake comprising, in combination;v - said element from said drum, an actuator coact- ~
a- rotatable drum and a braking mechanism for - ing with one end of said element for engaging
. said drum, said mechanism including a move
ment limiting device with screw members hav
said- element with said drum, stop means for lim
iting the retractile position of said element, a
ing coacting axially non-locking threads and self- ' ' stop device associated with the other end of said
50 adjustable axially in response and proportionately element to limit the movement thereof in one
to excessive movement of said mechanism, and direction by said actuator, and being automatical
stop means for limiting the extent of adjustment ly extensible in response to said spring means,
of said device in the direction of said movement. and spring means of lower power than said iîrst
24. A vehicle brake comprising, in combination,~ mentioned spring means and acting to resist ex
`
a rotatable drum and a braking mechanism for- tension of said device.
30. A brake comprising, in combination, a ro
said drum, said mechanism including an l,elon
gated movement limiting self-adjustable screw tatable drum, stationary abutment means, a pair
device automatically extensible in response to ,of iioating friction elements engageable with said
excessive movement, and a housing having tele
60 scoping sleeves enclosing said device and formed
with spaced interengageable abutments for limit
ing the maximum extension of said device.
25. A vehicle brake comprising, in combination,
a rotatable drum and a braking mechanism for
65 said drum, said mechanism including a self-ad
drum and having operative ends adapted to be
retracted against said abutment means, spring GO
means tending to retract said elements, a power
actuator for spreading said ends of said ele
ments, radial clearance means for limiting the
respectively rotatable and non-rotatable screw
retractile movement of said> elements from said
drum and being adjustable to vary the idle radial
position of said elements, and a ñoating circum~
ferential adjuster pivotally connecting the other
members with non-locking coacting threads-rela
-tively axially adjustable in response to an axial
automatically extensible in response "to circum
justable movement limiting device comprising two
70 force in one direction, and brake means oper
able in all relative axial positions of said mem
bers for resisting relative rotation of said mem
bers.
~
f 26. A vehicle brake comprising, in combination,
-75 a rotatable’drum and a braking mechanism for
two ends of said elements, said adjuster being
ferential tension adapted to be exerted by said '
spring `means in coaction with said clearance
means through said elements, and spring means
„ of lower power than said first mentioned spring
means for resisting elongation of vsaid adjuster.
31. A brake comprising, in combination, a ro
12
_f 2,106,167 `
tatable drum, stationary abutment means, a pair
of iioating friction elements engageable with said
drum and having operative ends adapted to be
4retracted against said abutment means, spring
of said elements, said adjuster being automat
ically extensible in response to circumferential
tension adapted to be exerted by said spring
means in coaction with said clearance means
through said elements, said adjuster comprising a
actuator for spreading said ends of said elements, case pivotally connected to one of said elements
radial clearance means for limiting the retractile - and defining an operating stop and an opposed
movement of said elements from said drum and abutment, ` a freely slidable non-rotatable vvend
being adjustable to vary the idle radial position face clutch element adapted for engagement with
of said elements, and a floating circumferential said abutment, two concentric screw members
adjuster pivotally connecting the other two ends having non-locking threads and constituting a
self -adjustable unit, the outer member being non-of said elements, said'adjuster being automat
ically extensible in response to circumferential rotatable and having an end pivotally connected
tension adapted to be- exerted by said spring to the other of Said elements, the inner member
being'rotatable and having- an end face clutch 15
means in coaction with said clearance means
through said elements, and spring means of lower element engageable in one position with said first
power than said first mentioned spring means mentioned clutch element to prevent rotation and
being movable under tension into engagement
for resisting elongation of said adjuster, said ad
with said stop to separate said clutch elements,
juster comprising a rotatable screw member con
strained against substantial axial movement, a and yieldable means tending to hold said first 20
non-rotatable axially adjustable screw member mentioned clutch element against said abutment
and permitting said clutch elements to remain in
` in non-locking threaded engagement with said
engagement in the event of a predetermined mo
first mentioned member, a positive clutch for pre
means tending to retract said elements, a power
venting rotation of said rotatable member in re
sponse to axial compression on said members, and
brake means for resisting rotation of said rotat
able member.
_
'
.
32. A Abrake comprising, in combination, a ro
tatable drum, stationary abutment means. a pair
of floating friction elements engageable with said
drum and having operative ends adapted to be re
tracted against said abutment means, spring
means tending to retract said elements, a power
mentum.
34. A brake comprising, in combination, a ro
25
tatable drum, stationary abutment means, a pair
of floating friction elements engageable with said
Adrum and having operative ends adapted to be
retracted against said abutment means, a power
actuator for spreading said ends of said elements,
30
radial clearance means for limiting the retractile
movement of said elements from said drum and
being automatically adjustable to maintain a pre
actuator for spreading said ends of said elements, determined braking clearance regardlessrof wear,
radial clearance means for limiting the retractile and a floating circumferential adjuster pivotally movement of said elements from said drum and ` connecting the- other two ends of said elements,
being adjustable to vary the idle radial position said adjuster comprising two relatively rotatable
of said elements, and a fioating circumferential screw members having non-locking coacting
adjuster pivotally connecting the other two ends threads and pivotally connected respectively to
said elements, one of said members being non 40
40 of said elements, said adjuster being automat
ically extensible in response to circumferential rotatable, the other of said members having a
tension adapted to be exerted by said spring limited axial movement >relative to the associated
means in coaction with said clearance means~ element and being rotatable upon coaction of said
through said elements, said adjuster comprising threads in response to axial tension, clutch
a ca_se pivotally connected to one of said elements
and defining opposed stops, two concentric screw
members having non-locking coacting threads
and constituting a self-adjustable unit movably
disposed in said case for engagement in retracted
50 position against one of said stops, the outer mem
ber being non-rotatable and having an end pro
jecting slidably from said case for pivotal con
nection to the other of said elements, the inner
member being rotatable and having an enlarged
head adapted for end bearing engagement with
the other of said stops upon movement of said
unit from said retracted position through a pre
determined limited distance, and end face clutch
means formed on said one stop and said head for
preventing rotation of_ said rotatable member to
prevent axial contraction of said unit when in
retracted position, and adapted to open upon
movement of said unit out of retracted position.
Y33. A brake comprising, in combination, a ro
means for preventing rotation of said rotatable 45
member in response to axial compression, spring
means resisting elongation of said adjuster, and
friction means yieldably resisting rotation of said
rotatable member. y
-
35. In a brake; anautomatically extensible ad 50
juster comprising, in combination, a cylindrical
case open at one end and adaptedto be anchored
at the other end, anon-rotatable screw member
extending slidabl'y, into the open end of said case
and adapted to bef/’anchored at its outer end, the 55
inner end of said screw member beingiormed
with internal non-locking threads having a high
lead and a relatively low pitch, an axially movable ',
clutch element mounted in said case, spring
means tending to hold said clutch element against
the pivoted end of said case, and a rotatable screw
member having external non-locking threads in
coacting engagement with said first mentioned
threads and having a clutch element adapted for
tatable drum, stationary abutment means, a pair _ engagement with said first mentioned element
of floating friction elements engageable with said and having a limited axial movement in said case
drum and having operative ends adapted to be re
tracted against said abutment means, spring
means tending to retract said elements, a power
actuator for spreading said ends of said elements,
radial clearance means for limiting the retractile
movement of said elements from said drum and
being adjustable to vary the idle radial position
of `said elements, _and a floating circumferential
75 adjuster pivotally connecting the other two ends
to open and close said clutch elements.
36. A vehicle brake comprising, in combination,
a stationary support, a rotatable drum, a brake
shoe pivotally anchored at one end to said sup 70
port, an actuator having a connection with the
other end of said shoe and being movable out
of a predetermined idle position» to engage said
shoe with said drum, yieldable means tending to
return said actuator to idle position, an adjustm
2,106,167
ble radial clearance stop for said shoe, and yield
able means tending to retract said shoe against
said stop, said connection including a` self-ad
justable non-locking screw device-automatically
extensible in response to axial tension and oper
able to permit return of said actuator to idle po
sition regardless of the retracted position of said
shoe.
37. A wear compensating device for maintain
10 ing a predetermined operating slack comprising,
ed to .an axial pull by said spring means after i
movement through said clearance, and means
for locking said members against relative rotation>
when said threads are subjected to axial compres
sion.
‘
39. A wear compensating device for xnaintain-v .
ing a predetermined operating slack comprising, »
in combination, an elongated case closed at one
_end and deñning an inwardly facing annular
shoulder, a rotatable screw member having an 10
in combination, a sleeve member having internal
longitudinal splines, a non-rotatable screw mem
enlarged head adapted for engagement with said
ber having external longitudinal splines slidably
coacting with said first mentioned splines, stop
threaded engagement with said rotatable mem
ber and projecting from said case, said members
being adapted for relative rotation when 'sub 15
means for limiting the outward movement of said
screw member in said sleeve> member to prevent
disengagement of said splines, a rotatable screw
member in said first mentioned screw member,
said screw members having coacting axially non
20 lòcking threads and constituting a self-adjust
' ing unit adjustable automatically in length when
subjected toan axial force in one direction, and
means for locking said screw members against
relative rotation when said unit is subjected to an
‘
_i
25 axial force in the opposite direction.
»38. In a brake, in combination with a sta
shoulder, a non-rotatable screw member in
jected to axial force in one direction, and an_
axially extensible and contractible generally
cylindrical _bellows of yieldable air impervious
material having an air-tight seal at its- ends re
spectively with the exterior of said case and the l20.
projected end of said non-rotatable member.
40. A compensating device for maintaining a
predetermined operating slack comprising, in
combination, a casé defining a rest stop and a
spaced opposed operating stop", two relatively ro
25
engageable with said drum, a stop for limiting the
tatable screw members constituting an adjusta-4
ble unit disposed in said case and having non
locking coacting' threads, one of said members -
retractile movement of said element from'said >
being non-rotatable and axially movable, the
tionary support,‘a drum, and a friction element
30 drum comprising, in combination, t'wo relatively
rotatable screw members constituting an adjust
ing unit and having non-locking coacting threads,
one of said members having a limited axial move
ment to deñne a release clearance between said
35 drum and said element and the other of ‘said
members having a freely separable operative con
nection with said element for synchronous move
ment therewith, spring means for maintaining
said connection, one of _said members being non
40 rotatable and the other of said members being
rotatable, whereby said unit is automatically ad
justable in length when saidthreads are subject-`
other of said Amembers having >a limited axial 30
movement with said one member through a limit
ed clearance from said rest stop into position for
engagement with said operating stop and being
rotatable against said operating stop by reason
of the coaction of said threads to effect an elon 35
gation of said unit when subjected to an axial
extending force, clutch means for 'preventing ro
tation of said other member when in position
against said rest stop, and brake means for fric
tionally resisting rotation of said other member. 40
HOWARD D. ‘COLMAR
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