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Патент USA US2107091

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Feb. 1, 1938.
Filed Sept.‘ 7, 1955
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2 Sheets-Sheet 1
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Feb. 1, 1938.
Filed Sept. ‘7, 1935 -
2 Sheets-Sheet 2
" wavy;
Patented Feb.‘ 1, 1938
‘Benjamin A. Swennes, Rockford, IlL', assignor
to Borg-Warner Corporation, Chicago, 111., a.
corporation of Illinois
Application September '2. 1935. Serial No. 39,522
10 Claims.
This invention has to do with a brake, and
. relates more particularly to improvements in a
vehicle brake:
An object of the present invention is the pro
5 vision of an improved vehicle brake employing
continuousconical braking elements relatively
axially movable into and out of braking engage
Another object of the present inwention isthe
1'0 provision of a new brake wherein braking power
(Cl. 188-71)
nating similar parts shown in the various ?gures
of the drawings and described hereinafter.
Reference should ?rst be had to Fig. 1 wherein
the device is illustrated as it may be applied to
a rear wheel of an automobile. The reference
character l0 designates an end of an axle housing
which is secured non-rotatively in any conven
tional manner to the running gear of the vehicle.
A generally triangular ?ange l I, shown in Figs. 1
Another object of the present invention is the
provision of a novel brake capable of great braking
and 2, may be formed integrally ‘with the axle 10
housing “I, ' and provides a support for brake
actuating mechanism hereinafter described. The
axle housing in comprises a bearing section 12
through which there extends an axle'l3. End
15 power with but a small pressure per unit area and
wise movement of the axle l3 in one direction may 15
is augmented by servo action upon conical friction‘
a concomitant preservation of brake lining.
Another object of the present invention is the
be prevented by a collar I4 secured to the axle and
abutting against an end of the housing bearing
provision'of a novel brake including “ an axially
l2. The collar I 4 rves as a seal to preclude the
leakage of lubricant from the axle housing.
movable arcuate'braking member having aservo
20 camming section with camming surfaces having
surface elements disposed radially of such arcuate
Still'another object of the present invention is
the provision of an improved brake capable of
25 maintaining relatively ~.high braking power
throughout a series of vigorous braking applica
tions made in rapid succession.
With theabove and other desirable objects in
view, one form of the invention is hereinafter set
30 forth and described in conjunction with the ac
companying two sheets of drawings hereby made
a part of this speci?cation, and wherein:
Fig. 1 is a fragmentary section taken through
the rear axle housing and wheel hub of an auto
;5 mobile, and illustrating‘the combination‘there
with of a form of the present invention;
Fig. 2 is a sectional elevation taken on the line
2--2 of Fig. 1;
Fig. 3 is a fragmentary side view of an internal
L0 brake member comprising a part‘of the brake
mechanism shown in Fig. 1;
Fig. 4 is a fragmentary sectional view taken on
the line 4-4 of Fig. 2;
Fig. 5 is a. sectional view of-the device taken on
15 the line 5-5 of Fig. 2;
Fig. 6 is an end view of the device, taken on
the line 6-4 of Fig. 5;
Fig. 7 is a fragmentary view of the leg of a
‘0 yoke used in the present brake structure and il
lustrating the use of a conical roller thereon; and
Fig. 8 is a side elevation of the conical roller
shown in Fig. '7, the view being ,takenon the line
8-8 of Fig. '1.
Like reference characters are used for desig
Keyed to the outer tapered end section l5 of the
axle I3 is a wheelhub IS, the keyed connection,
being shown at IT. The extreme end section l8
of the axle I3 is threaded and has a nut l9 turned
thereon for pressing a washer 20 against the outer
end of the wheel hub i 6 whereby to hold the hub
in place upon the axle. The hub I6 is journalled
upon the exterior of the bearing l2 by means of
roller bearings 20a. _
A plurality of bolts 2| are passed through a suit
ably apertured flange 22, and are there used for .
securing a brake drum 23 to the wheel hub I6.
The bolts 2| may be of such a length as to pass
through and beyond the brake drum, thus adapt
ing them to engage a wheel (not shown) for '
holding the same upon the hub l6. Theperiph
eral section 24 of the brake drum‘23 is of conical
formation, such section embodying one of the
friction elements of the brake. From the descrip
tion thus far given, it will be conceived that the
axle l3, the hub Hi, the brake drum 23 and-a
wheel (not shown) attached by means of bolts
2| to the hub l6 are interconnected so as to
rotate together as a unit relatively to the axle
housing l0 and parts presently to be described
supported upon the axle housing.
An internal brake member 26 is provided. The
brake member 26 may be of cast metal and has
a. conical section 21 whose external surface is of
the same pitch as that of the brake drum section
24. The internal brake member is in the general 50'
shape of a. hoop of which a half portion is shown
in- Fig. 3. A hoop-like friction element 25 ex
tends continuously‘ about the ‘ internal brake
member 26 in opposed relation with the friction -
element 24 of the brake drum 23. Ordinarily, the
friction band 25 will
secured to the internal
brake member 26v by E
of rivets, not shown.
Retracting means for the internal brake mem
ber 26 is provided by a number of helical con
forcefully into the camming sections SI and for
pressing the internal brake member into fric
tional braking engagement with the brake drum
Hydraulically energized means for pivoting
the yoke 44 is indicated generally by the reference
character 52 »in Figs. 1, 2 and 5. Paired lugs l3‘
traction springs 20 of which one is shown in detail
in Fig. 4. In the present embodiment of the in
formed within the upper section of the yoke “
vention four springs 29 are employed. The in
ternal brake member 26 is movable longitudinally have a‘ pintle 54 passed therethrough. Upon the
of the axle l3, but is normally held retracted ‘pintle there is pivotally disposed a link a. a cyl-'
from the brake drumby the springs 28. Fastened inder I6 is secured to the inner face of the ?ange
to the ?ange I I of the axle housing II is a circular l I by means of bolts I1 and nuts SI thereon. The
dust guard Ill having a short peripheral ?ange II
right end of the cylinder 56 is open and extends
and a cone shaped central section 82 containing a
through a suitable aperture to in the ?ange n. ‘
large central opening 12a. The dust guard II is
plainly illustrated in Figs. 1, 2, and 5. In Fig. 2
Within the cylinder “is a-piston '0 consisting of
a cup 6| containing a seat 02 for receiving the 15
there are shown the heads of four pins 33, which
rounded end 63 of the link It. Interlocked with
extend through apertures 34 spaced equi-angu
the base of the cup ‘I is a sealing member 64 hav
ing a skirt ‘I extending to the left therefrom,
Fig. 1. It is the function of the compoundly con
structed piston 60 and of the skirted member 84
to prevent the leakage of ?uid thereput within
the cylinder when ?uid is introduced under pres
sure into the left end of the cylinder through the
bore 66 formed within the section '1 for the con
nection of a ?uid supply conduit (not shown).
An air exhaust port 68 is communicative with
the interior of the cylinder I‘ to permit of the
escape of air, and thus facilitate the ?lling of the
?uid braking system with a ?uid pursuant to
larly about the dust guard ll. Pins 34 are used as
an anchorage for one end of each of the springs
20 29. The opposite ends of the springs 28 are hooked
about an internal ?ange 3| of the brake member
'28 and extended into apertures 36 in said ?ange.
‘Within diametrically opposed reinforced sec
tions 31 of the brake member 20 (one of such
25 sections being shown in Fig. 3) are formed cam
ming sections II. Each'of the camming sections
comprises opposed converging camming surfaces
39 formed by casting or otherwise effecting a
notch in the reinforced sections 31 and machin
30 ing the opposed surfaces II to make the latter
placing the system in- condition for operation.
smooth. It is to be noted that the camming sur;
Actuating mechanism for shifting the internal
After the gs'ystem has been ?iied with ?uid, the
opening 88 is closed by means of the screw cap ll.
When ?uid is introduced under pressure into
the left end of the cylinder '6, the piston SI and
the connecting link Ii will be moved to the right,
thereby pivoting the yoke 44 upon the pivot posts
II. The bore of the cylinder 58 is greater in di
ameter than the diameter of the link II, thus
brake member 28 axially into engagement with
providing a space for the insertion of a ?exible
. faces 38 have surface elements arranged radially
ofthe internal brake member 20;» that is, the
edges designated ":l” and “b" of the’respective
35 camming surfaces I. are on lines extending radi
ally of the brake member in contradistinction to
parallel lines.
40 the rotatable brake drum 2! for braking the lat
ter will now be described. Within each of the
two lower corners of the substantially triangular
?ange ii are anchored threaded pivot posts Ill.
Any position of the pivot posts ll axially of the
45 device may be selected by turning such posts
within their respective threaded sections ll of
the ?ange II. The selected axial position of the
posts It may be maintained by thereafter tightening the lock nuts 42 against the inner face of
50 the ?ange II. A spherical section 43 is provided
upon the outer end of each of the pivot posts 40.}
Pivotally supported upon the outer ends of the
posts ll is a yoke M having legs I! and 4' dis
posed upon opposlte- sides of the inner cone-like
55 con?guration ll of the dust guard 30. A full side
view of the yoke 44 is shown in Fig. 6. Recesses
41 having hemispherical concavities receive the"
outer rounded ends of the pivot posts II, the pivot
posts thus effecting a mounting'for the yoke 44.
Plvotally attached to the legs II and 46 of the
yoke 44 are similarly formed cams ll and If. -A
side view of the cam 49 is shown in Fig. 5. Pivot
pins II are anchored within the legs ‘I and l‘ for
holding the cams 48 and ll thereon. Each of
65 the cams ll and 40 has camming surfaces II for
cooperating with the camming surfaces II of the
cam sections in the internal brake member. 2..
Thecammingsurfacesil aresospacedandareof
and is contracted upon and into a circular groove
‘ll formed within the link it. Reciprocal move
ment of the link II pursuant to applying and re
leasing the brake device is unimpeded by the flex
ible member 10 and the ?exibility of said mem
ber prevents it from being impaired by the move
ment of the link relative to the cylinder wall.
The device is not restricted to actuation by the
particular type of ?uid energized means here il
lustrated, nor is it restricted to operation by a
?uid energized device of any kind. The yoke“
may be pivoted by any suitable type of mechan
ical device.
The operation of the brake is as follows‘. _
Normally, the springs 2| hold the brake mem
ber 2| and the friction element "to the left,
Fig. 1, out of engagement with the conical fric
tion element of the brake drum 23. When it is
desired to e?'ect a braking action between the
friction elements 24 and II, ?uid pressure is ap
plied, in any manner well known in the art, to
the piston CI for moving such piston, the link I‘
and the upper section of the pivoted yoke 44
to the right, whereby to press the cams 48 and
ll into the cam sections II of the brake mem-' 70
ber v28. It is to be noted that the earns 40 and
between the cam sections II and the cams 48
to be diametrically opposite with respect to the
70 against their respective 'camming surfaces 30 dur
ing operation of the device. The springs 2! are
effective to constantly maintain an engagement
and ll.
dust guard ‘ll, usually of rubber, between the cyl
inder wall and the portion of the link extending
into the cylinder. The outer ‘end of the dust
guard," is doubled about and contracted upon
thevright end of the cylinder wall while the left
end’of the dust guard ‘ll extends into the cylinder,
Pivotal movement of the yoke presses the cams
N are mounted upon the yoke in a manner as
axlsof axle ll. Whenthecams“ and?are
pressed against the camming sections 38 of the 15
2,107,091 .
brake member 26, the camming surfaces 5| will
bear more ?rmly against the camming surfaces
whereas tnev other camming surfaces SI of said
39. Incident to the friction element 25 engaging
the element 24, there will be a tendencyfor the
ming surfaces 38 to produce similar :servo action
friction element 25 and the internal brake meme
ber 26 to follow the movement of the wheel (not
is rotating in the opposite direction.
shown) and brake drum. and as a consequence,
.. there. will be a camming action between one
cams will cooperate with the other set of cam
when the brake is applied while the wheel hub
Particularly is attention directed ‘to the sim-‘
plicity of design and ruggedness of- construction’
of the‘ device herein shown. Thebrake actu
of the camming surfaces SI of each of the cams ating means proper includes but a single mov
10 4B and I9 and its mating camming surface upon ' able member, namely, the yoke, 44, .for advanc 10
the internal brake member. In this way, a servo ing the axially movable frictioif element into en
tion for more tightlyv engaging the friction gagement with the rotatable element 24. The
elements of the brake is produced.
, mechanism is compact inasmuch as it is‘ confined
Since the camming surfaces 39 have surface
15 elements extending radially of the internal brake
within the space embraced by the brake drum of‘
the wheel hub and the guard therefor.
A brake constructed in accordance with the
member l6, assurance is had of continued ?at
engagement between such surfaces and their re \present disclosure‘ls especially adapted to‘ with
spective complemental camming surfaces 5! upon stand severe service. - This has‘ been demon
the cams l8 and l9‘while sliding upon one an
20 other during the se'rvoicamming' action. In this
strated by -numerous_~_“fatigue" tests, which con
sist of ase'ries of-brake applications in rapid suc 20
.way, a free?at sliding contact ismaintained, ;' cession for deceleratlnga vehicle from high speed
and which would not be the case if the sliding. to a dead stop. ' The brake has been found‘to
surfaces were permitted to tilt relatively to each maintain its braking e?iciency much‘longer'dur
other thereby ‘creating a tendency for the ma
ing a “fatigu‘e’-’ testi‘than do conventional vehicle
25 terial at the edge or corner of one of the sliding brakes. This is attributable in part to the great
surfaces to dig into the other. The provision of er \surface area of brake band upon the continu
this improved servo action has been found to ous circular conif‘orm element 25, whereby the
reduce materially the'amount of brake applying braking force per unit area is diminished. Also
force necessary upon the brake pedalin the driv
the pressure is uniformly ‘distributed over the
er’s compartment of a vehicle.
braking area of the friction element“. In this 30
If desired, the cams 48 and it may be replaced ‘respect it is to be notedv that the conical internal
by frusto conical rollers ‘le‘shown in Figs. 7 and brake member 24 may 'belmade as heavy as de
8. Where, therefore, the term' “cam" is em
sired to give to it the rigidity required to prevent
ployed in the appended claims it is to be con
its straining under the pressure exacted thereon
35 strued generically to embrace either a cam in its through. the yoke It and the cams l8 and >49.
strictest sense,-a roller, or any device operative Likewise, the yoke 40 maybe constructed with
to de?ect the'internal brake element.
’ legs of a thickness adapting them to carry the
- Upon a subsequent release of ?uid pressure he
hind the piston‘ 60 within the cylinder 56, the
40, force component of ‘the cams 48 and 49 opposing
force applied thereto without perceptible strain.
Elimination ofstrain in the brake actuating parts
is essential to precision-in operation. Each leg
' rotation. of the internal brake member 25 will be
of theyoke 44 serves as a lever through which
terminated; the member 26 will thus be per
mitted to rotate a slight amount with the brake
but a, part of the braking force is-transmitted.
This, together with the 'fact that the legs of the
yoke are short and are subjected toi'no torsional
stress makes it possible to employ a relatively
drum whereupon the. icamming sections of the
45 member 26 will de?ect the yoke M and the cams
thereon inwardly. Thus the action of ‘the cams
and their co~acting cam surfaces upon the brake
member cooperate with the springs 29 in the re
lease, of the brake, for the only resistance, if any,
50 the arms and yoke may offer the spring force in
certain instances would be in virtue of their in
ertia. Should the came 4! and I8 and the canv
light .yoke.
I claim- as my invention:
1. A brake comprising an arcuate axially dis
placeable friction. member, an axially movable
cam for displacing said friction member, a piv- ‘
oted brake actuating member in support of said
cam and actuative incident to a pivotal move
ming sections of the internalbrake member 26 -ment thereof to cause such axial movement of
operate to retract the yoke 44 more slowly than
the springs‘ 29 operate to retract the internal
brake member, the springs will retract the whole
assembly including the internal brake member,
the c
and the yoke. The manner in which
the yoke 4t, the‘cams 48 and 69, and the in
00 ternal axially movable brake member of the'pres
ent device are actuative incident to brake re
lease, prets all likood of locking of the
brake members, thus obviating the principal ob
jection to many brakes employing the servo prin
65 ciple of operation.
In Fig. 5 it can be ‘seen that
the return movement of the yoke 46 under the‘ in»
?uence of springs 29 is limited by the heads of
bolts 57. .Bythus limiting the movement of the
yoke, it is prevented from. coming in contact with
the sealing member 85 and injuring the same.
Application of the brake while the wheel hub
I5 is rotating in one direction will result in the
camming surface ti on one side of the cams 4c
and 49 coopera
with one set of cumming
surfaces 39 to bring about the servo action,
the said
f vand said friction member.
2. A brake comprising an arcuate ‘axially dis 55
placeable friction member having a servo cam
ming section, a pivoted brake actuating mem
her, a servo cam on said member. said cam being
opressed against such c‘amming surface to effect
axial displacement of said friction member, in
cident to a pivotal movement of said pivoted
3. Abrake comprising an arcuate axially dis?
placeable friction member having‘a servo cam
ming section, a brake actuating member ‘pivotal
about an ams substantially normal tovthe axis
of. said friction member, a servo cam on said
member, said cam being pressed against'such’ ,4
camming surface to effect axial displacement of
said friction member coincidental with a pivotal 'lol
movement of d pivoted member.
.4. A brake comprising arcuate relatively ax
ially movable friction members, one of said mem
bers ha
a servo camming surface. a brake"
applying member pivotal about an
normal to
and at one side of the axis of said friction mem
bers, and a cam on said brake applying member
at a section removed from such normal pivotal
axis thereof and movable with’said brake apply
ing member to apply pressure against such cam
ming surface for co-engaging said friction mem
bers coincidental ‘with a pivotal movement of
said brake applying member.
5. A brake comprising arcuate relatively ax
10 ially movable friction members, one of said mem
bers having servo camming surfaces, a support
member, a substantially U-shaped brake apply
ing member disposed'with a leg thereof on each
side of the axis of said friction members, each
camming surfaces having surface elements dis
of said ,arcuate member.
9. In a brake for ‘a wheel having a friction
element thereon, a friction member movable ro
tatively and axiallyof’said wheel into engage-w
ment with
:friction,)element, there being
servo camming.
said friction member
and having
camming surfaces,
a support member, a yoke having a main body
disposed in a plane substantially parallel, with
the plane of said wheel and with the legs thereof
on opposite sides of the axis of said wheel, a
pivotal connection between such legs and said
support member permitting of movement of the
leg being pivotallyconnected with said support
main body of said yoke toward and away from
member, and a cam upon each leg of said U
vsuch wheel friction element, servo cam members
pivoted upon the legs of said yoke, said. cam
shaped member, and movable therewith to apply
members being disposed between the camming
surfaces ‘of such camv sections and compressible
thereagainst to elect an initial engagement be 20
tween said friction member and friction element
during movement of the yoke main body toward
6. A brake comprising arcuate relatively axial
ly movable friction members, one of said mem ,said element, said cam members having inclined
for abutting against the cam
bers having servo camming surfaces, a support camming
member, a yoke having end sections of its legs ming surfaces "or the rotatable friction member
and limiting rotationv thereof with the wheel '
pivotally mounted upon said support, yoke piv
pressure against such camming surfaces for co
engaging said friction members coincidental with
20 a pivotal movement of said brake applying mem
oting means comprising means for applying force
friction element, the inclination of such cam
to said yoke axially of said friction members,'. ming surfaces being such as to de?ect the fric
and a cam upon each leg of said yoke and mov
able therewith to apply pressure against such
camming surfaces thereby effecting co-engage
ment of said friction members, coincidental with
a pivotal movement of said yoke.
7. A brake comprising a brake support mem
ber, an arcuate friction element‘movable both
axially and rotatively and having a cam section
including opposed inclinedv camming surfaces
tion member toward said friction element inci'-\ '
dent to precluding rotation of said friction mem 30
10. A brake comprising a rotatable‘ brake
drum, an axially movable brake element for fric
tionally engaging said drum to resist rotation
thereof, said brake element having limited rota 35
tive movement with said drum,‘ means yieldingly
urging said element away, from said drum, a
thereon, a complemental friction member to be brake actuating member advanceable in one di- '
braked by said movable friction member and ‘motion by a brake applying force, a de?ecting
adapted to limit axial movement thereof, a brake member upon said' actuating member and adapt 40
applying ‘member’ pivoted upon said support
member, acam on said pivoted member and
having cam surfaces between and in opposed re
lation with the cam surfaces of said friction
member, and means for pivoting said brake apé
plying member axially of said arcuate friction
member thereby pressing, said cam against the
cam section of said friction member and caus
ing said friction member to move axially into
engagement with the friction member to be
braked thereby.
8. In a brake, an arcuate friction member
having a servo camming section thereon, such
55 camming section including opposed inclined
ed to advance said movable element into an in
itial frictional engagement with said drum inci
dent to such movementof said brake actuating
member, such initial frictional engagement of
the movable element and drum causing such lim 45
ited rotation of the brake element with the drum,
said de?ecting member being disposed for de
?eeting said brake member into a final frictional
engagement with said drum coincidental with
such limited rotation of said element; and said 50
element, said de?ecting member and said brake -
actuating member being unitarily retractable by
said yieldingly urging means upon cessation of
the brake applying force.
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