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Патент USA US2404397

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July 23, 1946,
J. G. oE'rzEL
_ 2,404,397
Filed Novl e, 1944
'47 40
2 sheets-smet 1'
July 23, 1946.
J'. G. og-:TZEL
-Filed Nov. 6, 1944
.2 sheets-sheet 2
,9, 44.W4H ma
Patented 4July 23¿ 1946
” 2,404,397
Y 2,404,397
ÍGeorge Oetz'el, Beloit, Wis., assignor to".
Ill., Manufacturing
a corporation ofCom‘Illi-’V i.
' , lapplioaiionnovemboro,1944, serial No-56ai1à l"
s claims. (C1. 1ss_141)
“This” 'invention relates to a `brake 'mechanism
of the internally expandable'type energized in
response to Afluid -~ pressure changes.
Oneobject is to providefa brake mechanism
ofv this‘character by which a substantially greater
retarding torque is Vvobtainable than in prior
„ mechanisms of the same type.
A more detailed> object ,isto augment the ñuid
pressure source applied to a’ main brake element
through the intermediary.V of 'an auxiliary friction
I -The invention also‘re'side's in the novel manner
of mounting the-fluid pressure Aactuator so -that
its-available force maybe' utilized to `best me
chanical advantage.V
Other'objects and advantages or the invention
will become apparent'frcm the. following ldetailed
description taken in connection With'the accom
panyin'gl drawings, in whichv
Contractile springsV I.'I stretched between the shoe
brackets I4 normally maintain the main friction
element contracted with its shoe surfaces I5 en
gaging the abutments I6 as shown in' Fig. ‘1,
the main brake then being released.
. ì
" The main friction element `is expanded against
the drum by a' forcel derived infpart from the
momentum of the rotating part; This is accom
plished through the medium o_f an auxiliary fric
tion element engageable‘in this instance withy the
inner >end portion of the drum surface 5 and
movable bodily ‘with the rotating drum through
an angular distance suliîcient to expand the main
element.- In the present instance, _the auxiliary
16 element comprises a. pair, of r semi-circular shoes \
20 covered with friction‘inaterial 2l and arranged
in end-to-end relation with their adjacent ends
spaced apart and disposed _on diametrically op
posite sides vof the’ drum but angularly spaced
‘ Figure 1 is an end viewrpartially in section of 20
from the ends of the main shoes 9.
a brake mechanism embodying the novel fea
tures of the present invention, the section being
taken along the liner I-I of Fig. 2.k
Fig. 2 is a section taken along the line 2_2 of
vFigsf'3 and fiarevi'ews similar togFigs. land 2
showing a modiiiedwform _o_f the_invention,.the
sections being takenly long the lines 3+3 and
4-_4 of Figs..4 and ‘3 respectively. ‘
, _
I The brake',m'echanismsfvshown for purposes of
illustration are 'adapted for' expansion of their
friction .elements-- into gripping l engagement with
thev internal cylindricalsurface r5 of .a drum 6
The shoes
20 are supported on the peripheral surface 22 of
a second anchor member 23 whose hub 24 is jour- '
naled on the hub 25 of the ñrst or non-rotatable
anchor member II. Outwardlyiprojecting arms
23a on the second anchor member `23iprovide
oppositely facing abutments 26 engageablewith
plates 21 on brackets 28 which are secured'along
the center line and on the inner Vsurface of the
auxiliary shoes 20. Contractile springs 29.'nor-.
.valo mallymaintain these shoesycontracted against
the abutments 26.
rwhen the auxiliary friction sho-esilio are'ex- f
panded into vgripping engagement with the rotat
the corresponding endswîll. anchor on
ed in the usual way 0n alyehijcle ‘wheel'or other 35 the drum,
26, and the shoes, vtogether with
rotary part whose motionlis to be controlled. In
the anchor member 23.-will turn lbodily with the
this instance, vÍthe‘drum andthe vehicle wheel
having an inturned flangelfwhich may be mount
rotate about'a stationary axle 8 projectingaxi
ally through the drum,
1 .
The mechanism shownin Figs‘l and 2 isespe
cially adapted for _the use of air as the- actuating
iluid.í„This mechanism` includes a main friction
element adapted’fvor .expansion against the> zone
drum in the directionof rotationv of` the latter.
This motion of the shiftable anchor is multiplied
mechanically and applied to the corresponding
ends of the main shoes 9 to~expand`the- latter
against the drum. For this purpose, crank arms
3I project radially inwardly. from `pivots 32'which
extend between spaced portions 33and 34 of the
main anchor II and are disposed adjacent the
drum surface 5 between the ends of each pair of
main shoe ends. At their inner ends, the crank
arranged in end-to-end relation with their .ends
arms 3| have slots 35 receiving pins 36 which pro
spaced apart on diametrically opposite sides Aof
ject from the Iioating anchor 23. Projecting from
the drum. `The shoes are supportedby an anchor
opposite sides of the crank arms intermediate the
member. in .the .iorin‘cfA a casting „Il , fastened 50 ends thereof are pins 31 which are engageable
by" Lbolt's ’I2 to a _flangeflíi on the axle .ßfand‘s‘ubà
with the ends 38 of the brackets I4 on' the mainV
stantiallyïclosing -the- openend :ofmtheî drum.
of tlie‘surfac'ef5 ne'ar the open end of the drum.>
The' element. is rcomposed ofy two semi-circular
shoes .,9'covered vwith friction material . I0 and
Bracketsv I4 Welded to vthe inner sidesÍof _the shoe
endsprovide .abutment ` surfaces I5§ engageable
wìthLIabutments rI6 on the anchor Amember ÁI I.
shoes 9, these bracket endsstraddling the crank.
Thus, one shoe end 38 will be moved away from
its anchor I6 as the crank 3| is swung from the`
brake-released position shown-_in Fig. 1 tothe
.1Q Í ”
actuators may have comparatively short strokes
determined by the maximum shoe clearance ob
tained in service operation between the auxiliary
shoes and the drum. When the actuating fluid
are returned i
pressure is relieved, all of vthe parts
_ l
y , position shown in phantom. After normal clear
, ance has been taken up, the shoes 9 engage the
drum andare held pressed against the latter so
long as the auxiliary friction element remains
energized. Upon contraction of thelatter, the
to brake Areleased position. by: the“- action of the
springs 'l1 contract themain friction element and
‘springs |1 and 29.
` return the crank arms to released position.
The ends of the auxiliary shoes are spread apartv . , ,
Figs. 3 and 4 show’ a modification of the im
proved brake mechanism adapted for actuation
` by iiuid pressure Operators 40 which, in accordance "
i with the present invention,'are mounted >on 'thefmîg hydraulically.
In this form, the main and aux
È iliary friction elements are mounted and inter
l ñoating
as to minimize
member 23 to travel therewithlso
length of the actuating strokes . ` ' connectedin the same manner as in the mech
Í-a-nisnr..ñrst described, and the various parts are
In Figs. 1. and 2:,.theoperators'
» 49 comprise air cylindersA'Iff» angularlly spaced "y correspondinglynumbered. In this case, how
ever, the cylinders24| of the hydraulic actuators
` around the drum from the shoe ends 28 and se
40 are smaller in diameter vowing to the higher,
cured as by welding to the exterior of the hub 24 _
, of the operators.
l on the anchor 23 with the axes of the' cylinders `f
pressures that may be employed, and are dis
j secured to the hub 24 and communicating through
thatY the piston motions are thus applied directly
ï aflexible conduit 44 with a ñtting45 onthe pri-L
,apart against the Yaction of the returnsprings
29'.' which, v'in thisfinst'ance, extend fromthe
parallel to each otherf and extending along chordsj ` posed» immediately adjacent the ends of the aux-> '
iliary shoes. The pistons 41 ‘ are connected
I of the drum axially spaced inwardly from the
through the .links 48 directly to pivot pins v58 on
cranks 3|. l Conduits '42" communicate'«with> the
the-,brackets 28. of the. auxiliaryv shoes` 20 so
1 centers of the cylindersïand lead to a fitting
to »spreadthel ends of; the auxiliary shoes» ‘x20
i mary anchor ||„ A conduit 46 extends'frorn the
latterA fittingthrough the anchor || and is Icon
brackets 28 to points on _the -floatingyanchor V23. .
The operation of this form of _the brake is iden- '
nected to a pipe- 51 Vfor conveying compressed air
` to the .brakermechanismffrom afsuitable source
` of supply,
tical> with that vof. thev first form. describedî above.
the delivered pressure being regulated
. . ItA willbeapparene from the >foregoing that .the
i inthe usual' wayby a suitable valve.
Within each cylinder 4| are two pistons 41 con- I'
s ì nected to ,links 48 which projectthrough dia
auxiliary 'friction element which is> energized-4 by `
the pressure actuated..devices derivesan actuat
ing force from the momentum of thepartito be
; phragms 49 -and _from opposite Yendsof .the cylin»
braked which force is applied tothe mainshoes
ject in the same direction from the two cylinders 35 and in magnitude is many times that of thelpri
marypactuating force. .Bothl-the main and. aux
-are pivotally connectedfto r_the long. arms of bell
iliary >shoes s ,may> anchor . at .either ...end yso «that
cranksâ'l which areful'crume'd on pins 52 circum»
the full lengths vofall four >'shoes are effective in
f ferentially spaced apart andprojecting inwardly
either direction of drum; rotation.,l Therefore,
Vfrom the .floating anchorV 23 and parallel to the
even thcughthefluidpres'sure is derived by Yman
drum- axis.
bell cranks
and have
5t*> i ual effort, apowerfu-l retarding torqueis pro
duced without the'` necessity of employing large
54 bearing against .the-ends'55 of extensions on
mechanical ratios in-.the force transmittingk con
' the 'brackets 28 o_f the auxiliary shoes 20. The
nections and with dangerv oían. uncontrollable
bell cranks are bentj as shown in Fig.- 2 to permit
ders. The out'erends of'those links which' prof .
wrapping actionvbeing developed.
of suchoverlapping.
application is a _continuation-impartîof
With the parts‘disposed in brake-released posi-Y 45 my.This
co-pending/ application SerialN'o. 448,251,
tion shown and the drum turning clockwise, the
brake mechanism'shown in Figs. land 2 oper
ates in the- following manner> in response to the
admission; of pressure ñuid to they cylinders; _4|
I'claim as myinvention;
1. A brake mechanism having, inl combina
tion„ two shoes arranged endv to‘end withtheir
pairs >of ends spaced apart, an anchor member,
through the conduit 44. Bothv pistons ¿in each
cylinder iirst move outwardly, and, through' the
anchors for said shoe ends carried by
Y medium of the levers 5|, move all ‘four ofthe ' labutment
said member, twopairs ofbell-,cranks respec
shoeends 21 away from the anchor >abutments 26.
supportedl by circumferentially spaced piv
Assoc/rnÍ as- the> shoes engage the drum surface ' «tively
relative to and carried by said anchor
5, they shift bodily with the drum'until’their lead?
member. adjacent said shoe ends, the bell-cranks
ing ends, as determined _by the direction of drum
rotation, com'eagainst their'anchors 25, where-Ã
uponV the Yother> shoe ends move farther away
from.l their anchors and receive the full actuating I
force developed by the respective actuators 4D. '
' The reverse action takes place when the brake is'
applied with the `drum rotating counterclockwise‘
The friction force resulting from engagement;
of the auxiliary shoesv 20 with the drum moves'
theseA shoes and their floating anchor 23 in the
direction of d-'rum rotation, whereupon 'the pins
35y swing'theV crank arms 3| to the'positionjshown
.in phantom in- Fig. 1,Y thereby movingthe'corre->
sponding ends 38' of the main shoes 9' away from
their anchors V|§|5 so vas to expand the main' fric-ï
tion`V element.“ _Inasmuch as the fluid’pr'essure
actuators >4|) are’mounted on the floating anchor
23kto shift therewith, it is unnecessary for the
operators 45 tov takeup the motion incident to',
actuation of the main shoes. As >a- result, the fluid"
of each'pair having short arms engaging the ends
of onepair of shoes and long arms extending- cir
cumferentially in opposite directions, two fluid
pressure cylinders stationarily mounted with re
spect to said anchor member, their Vaxes extend!
ing parallel to eachother between saidl pairs of
shoe ends, two pistons in each of saidcylinders
respectively connected to two of said long. arms,
and' pressure fluid supply'means communicating
with the interior of said cylinders between V,the
pistons Itherein.
` `
2. A brakemechanism having, in_combination,
two shoes arrangedl endto _end with their pairs
" of , ends spaced apart, ananchor membenabut-V
ment, anchors> for ~said, shoe yends ' calrrie<`j1> by' said '
member' andy permitting _movement _jo-f ._ the shoe.
ends circumferentiallyaway from the anchors;
two 'pairs 'of f levers forÍ actuating fthe respective
shoe 'ends eachY pivotally supported by’said'm'em- ^
ber, the levers of each pair extending circum
ferentially in opposite directions, two iiuid pres
sure cylinders stationarily mounted with respect
to said member, two pistonsin each of said cyl
inders, and means connecting the pistons in each
cylinder to two levers of the different pairs and
actuating the levers unidirectionally in response
radial expansion while anchored on said mem
ber, a second anchor member mounted on said
first member to turn about-the axis of said ele
ment in either direction .away from a normal l
brake-released position, a pair of auxiliary fric
tion elements arranged in end-to-end relation.
and having pairs of separable ends adapted to
to a pressure increase.
anchor selectively on said second member, a
3. A brake mechanism having, in combination,
pair of fluid cylinders rigid with said second
an expensible friction element having ends spaced
anchor member and each having a pair of pistons
apart, a member providing an anchor disposed
therein, means connecting said four pistons to
between said ends, two pivot pins carried by said
the respective ends of said auxiliary friction
- member providing axes which are fixed relative
elements to separate the ends of each pair in
to the member and are disposed inwardlyr from
response to an increase in the fluid pressure in
said ends and circumferentially spaced apart, a 15 said cylinders, means for conducting pressure
bell-crank fulcrumed on one of said pins and
fluid to said cylinders between the pistons there
having a short arm bearing against one of said
and means connecting said second anchor
ends and a long arm extending across the other
member and said main friction element to ex
of said pins and circumferentially around said
pand the latter upon movement of the second
drum, a second similar bell-crank fulcrumed on 20 member in either direction away from said brake
the other of said pins with its short arm bearing
released position.
against the other of said ends and its long arm ex
tending circumferentially in a direction opposite
combination, an anchor member adapted to be
to that of said first mentioned long arm, two par
mounted non-rotatably, a main friction element
allel cylinders, and pistons in said cylinders re 25
of annular form mounted on said member for
spectively connected to the free ends of said long
radial expansion and to anchor on the member,
a second anchor member mounted on said first
4. A brake mechanism having, in combina
member to turn about the axis thereof in either
tion, an expansible friction element having
separable ends, a member providing an anchor 30 direction away from a normal brake-released
position, an auxiliary radially expansible friction
disposed between said ends, a bell-crank ful
crumed on said member to turn about an axis
which is fixed relative to said member and which
is disposed adjacent said shoe ends, said bell
element of annular form anchored on said second
member and supported thereby for bodily angular
movement therewith about the axis of said
first element, a fluid cylinder rigid with said sec
crank having a short arm bearing against one 35
ond anchor member and having a piston therein,
shoe end and a long arm extending circumfer
connecting said piston and said auxiliary
entially around said drum, a second similar bell
friction element to expand the latter in response
crank fulcrumed on said member adjacent said
to `an increase in the fluid pressure in said cylin
shoe ends with its short arm bearing against
der, and means connecting said second anchor
the other end'and its long arm extending cir 40 member
and said main friction element to expand
cumferentially in va direction opposite’to that of
the latter upon angular movement of the mem
said first mentioned long arm, twov parallel cylin
ber'in either direction away from said brake
ders fixedly mounted with respect to said mem
released position.
ber, and pistons in said cylinders respectively
8. A friction brake mechanism having, in
connected to the free ends of said long arms.
46 combination, an anchor member adapted to be
5. A friction brake mechanism having, in com
mounted non-rotatably, a second anchor mem
bination, an annular» main friction element
ber mounted on’ the first member for angular
adapted for expansion of its peripheral surface
movement about an axis, a main friction ele
by circumferential separation of its ends, a non
rotatable member providing an anchor for said 50 ment concentric with sai’d axis and adapted for
radial expansionwhile anchored on the member,
element, a ring journaled on said member to
an auxiliary radiallyexpansible-friction element
turn about the axis of said element, an annular
with said axis and anchored -on said
auxiliary radially expansible friction element
second member for bodily angular movement
having separable ends adapted to anchor on said
ring, a cylinder rigid with said ring with its axis 55 therewith, a fluid pressure operator having a
cylinder and mounted on said second anchor
extending along a chord of said auxiliary friction
member for angular movement therewith,` means
element, pistons within said cylinder respectively
connecting said operator with said auxiliary fric
connected to the ends of said auxiliary element
tion element to expand the latter in response to
to separate the latter upon an increase in the
iiuid pressure in said cylinder, and means for 60 an increase in the fluid pressure in said cylinder,
and means connecting said second anchor mem
introducing pressure fluid in said cylinder be
tween said pistons.
ber and said main friction elementV to expand ,
the latter upon movement of the second member~
6. A friction brake having, in combination, an
in either direction away from said brake-re
anchor member adapted to be Vmounted non
leased position.
rotatably, a main friction element adapted for 65
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