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Патент USA US2282620

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May .12, 1942.
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BRAKE
Filed Jan. 16, 1941
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2,282,620
Patented May 12, 1942;
, UNITED . STATES PATÉNT '__joFF-ICE y
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.zasaszo
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ams
Harvey'c. swu'_¢,.netmu, man., [email protected] ny.
.
draulicV Brake Company, Detroit. Mich., arcor;4> i ‘
poration of California
appueationianum is, 1941, sensi Naan-,15s.- _
s claims. (ci. iss-79.5)
This invention relates to brakes, and'more
specifically toï’automatic adjusters for the fric
tionelements
thereof.
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Broadly the invention comprehends means for
automatically adjusting the friction elements or
shoes of an internal expanding brake to zoom
pensate forvw'earon the liningsof the shoes »due
to'repeated'braking operations.,>
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Generally‘fin the type of 'automatic adjusting v
onk the shell.y Springs hold the 'lever adjacent
its iulcrum and the member frictionally againstV
thel same side' ci thefweb of the shoe.='
'Fui‘therrobjects and' features of the invention
_ will- appearV vfrom theiollowing description' taken
of '-the speciilcation; and ‘in which
Fig. lis a> vertical sectionalV viewjof'a brake ; _`
taken just back 'of th'ehead Vof -the'drum illus'
means wherein the operation is dependent upon
trating the invention as applied;
a differential of wear on the-‘friction linings of
the shoes and a member frictionally clamped to
tially on line 2-2, Fig-1; and
the` shoes-andîvadapted for cooperation with the4 -`
drum, and an' adjustable retractile stop formain'
or drum engaging member.
taining 'theîshoesl in proper spaced relation _to
'the` drum,v when the brake is at rest, a consid-»_>
erable force is required to movethe frictionally
clamped member relative to the shoe. It lis íalso
understood that because of I'the tension ofthe
retractile- spring-’connecting the shoes, there-is a
tendency to displacement of the- frictionally
clamped members when the shoes are returned
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in connectiongwith'th'e drawing forming'ra part'
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Fig.' 2 is an-’enlar‘gedsectional view substan
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‘ Fig. 3 is atop plan-'view_.of’the'ceramic block
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Referring »to the'IV drawing for more specific o“
details of the invention', Il) representsV ailxed'
support or vbacking ipla‘te. Associatedwith the -
backing -plate isf-"'a'rotatable drum _I2 ?and a pair
of _ corresponding interchangeable' 'friction ele# '
ments or shoes i( and I6 mountedïon the [email protected]
ingy plate for cooperation'with the drum.
As shownythe shoes> are of conventional type
each including ¿aweb' I8 supporting a rim> 2liV
having I suitably secured" thereto frictional li_n-‘l
cornes necessary for the -friotional resistance to
movement‘of the members toexceed the load 25 ing 22. ¿The shoes Il and I6 have their articulate'
ends pivotaily 'mounted on spaced anchors 24'
an the `retractile stops, otherwise an underad
and ‘26 positioned yon the backing plate, and cor--V
justment `would result. A `It is the aim of 'the
responding adjustable-retractile stops 28 and 30
present-invention‘to overcome this objection.
to their retracted positiom> Accordingly, it be-_
An object of the invention is to provide means
for automatically adjusting the friction elements
or shoes of a brake to compensate for wear on
the frictional linings of the shoes, operative _to
avoid improper’adjustment thereof.
_
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A feature of the invention is a member sup
ported on a- friction element movable relative
-theretol and cooperating-with a drum and an ~
adjustable retractile stop and means interposed.
between the member and the stop for inhibiting
retrograde> movement of the member.
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Another feature of th'.` invention is a non
frictional member
erably> a ceramic
high compressive
agonally disposed
of' 'impervious material, pref
member of ñne texture and
strength having one side di
with relation ‘to the proille
also positioned-'on
backing plate support the
shoes in 'proper spaced relation to the drinn.
when the brake _is 'at rest.
A retractile cspr'i`ng""22 >connecting the'shoes>
il -and I8' serves to return the shoes to' lthe
stops.”V and Iii-,upon conclusion of' a.v braking
operation- andV to retain the' shoesonv the stops
when the brake is at rest.v Each of_ theïstopsY
includes a shaft.“ rotatable in the backing 'plate
Il. Thel shaft has thereon a`co1lar'38 abutting
the-backing plate and ilapsßß on its 'freefend I
for the' receptionof an adjusting tool. f A washer
I0 is sleeved onlthe `shaft and- a nut I2 threaded»~
on'the" shaft'serves _to secure the assembly in
_ the adjusted position.-
’
A num pressure-actuated motor“ of 60h-,
_of the member adapted to slidably engage an =f ventional type mmmted >on thejbackmg plate'
between the shoes "il and I8 and adapted to be'
arm rotatable on a pin carried by the forcé
transmitting end of a lever anda shell support
ing the pin adapted to eliminate dust and other
foreign substances.
More speciiically` the shell is fixed to the fric
tion element or shoe and houses the ceramic
member and forms a support for the movement
of the member transversely` of the shoe. The
lever is fulcrumed on the web of the shoe within
the shell and holds the member against its seat
connected to a suitable source of'ñuid pressure> L
is operated to actuatelthe >shoes into engage-j
'ment with Vthe drum against the resistance of:`
the retractile spring 3L
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' Mounted onthe shoes in reverse position are
automatic adjusizersv indicated‘generally at 40.V
As shown. the rims and the linings'r of the shoes
are slotted as at 48; Thewebs of the shoes have'
bores 50 and _arranged on the _webs are shells
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2,252,620
/
52 spot welded thereon, having bores 54 there
through concentric to the bores inthe webs.
,
block are reduced to a. minimum.
Each> of the adjusters includes a lever 56 hav
ing as its fulcrum a pin 68 fitted in an opening
60 in the lever and coextensive with the bores
It is to be clearly understood that applicant
does not limit himself to any particular ceramic
in the production of the drum engaging member
or block. However, it is important that such ce
ramic as may be employed mustibe durable and
substantial so as to withstand the shock and
50 and 54 to permit rotation of the lever.
The lever 56 has an aim 62 of short radius
and a driver end 64 suitable for> engagement with
the associated adjustableretractile stop. ,
A block 66 of impervious non-frictional ma
.
a high degree that the abrasive properties of the
strain imposed thereon in brake structures.
10
In a normal operation, -pon energization of
terial has a slotted diagonally disposed side 68
the the motor 44, the shoes
and I6 are moved
carrying a metal insert 10 therein, parallel the ' into engagement with the drum I2 against the
diagonally disposedA side. One end of the> block
resistance of the retractile spring 32 effectively
has a radius commensurate with the radius of
retarding rotation of the drum. During this op
the shoe and this end of the block is fitted for 15 eration, the respective assemblies of the auto
movement in the slot 48 through the rim and
matic adjusters“ and the shoes I4 and I6 move
lining of the shoe and is adapted to engage the
as a unit.
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drum. The metal insert 10 on’the diagonal side
Further movement of the shoes I4 and I6 into
of the block bears against a curved portion 12
the drum I2 results from wear on the linings of
of the arm 62 of the lever. One side of the 20 the shoes due to successive engagement of the
block slidably engages the inner wall 14 of the
shoes with the drum. There is no undue unit
shell 52 and is-pressed against the web of the
pressure exerted on the blocks 66 in comparison
shoe by an arch spring 16. A thin washer 18
to the unit pressure on the shoes, the wear on the
Iiapped-against the web of the shoe and a pin 80
drum engaging portion of the’block is nil as com
passed diametrically through the pin 58 serve 25 pared to the wear on the linings 22 of the shoes,
to hold the pin 58 in position as well as assist
and this relative movement results between the
in clamping the lever to the web of the shoe by
blocks~ 66 and the shoes I4 and I6.
bearing upon the shell to -place tension on a
Movement of the blocks 66 is lrestricted to
spring washerv82 received by the pin and in
paths transverselyof the shoes I4 and I6 by the
serted between the shell and the lever.
30 wall 14 of the shells 52. Upon wear of the lin
Due to the differential in the coeillcient of fric
ings 22, the shoes are caused to assume new po
tion of the lining and the block, in a normal
sitions relative to the block 66 and levers 56. 'I'he
braking operation there is relative movement be
movement of the blocks 66 upon wear of the lin
tween the shoe and the block. This movement of
ings 22 results in transmission of force through
the block is proportionate to wear on the lining 35 the block and metal insert to the arm 62 on the
lever causing a clockwise rotation of the lever.
on the shoe and is transversely voi.' the shoe
against theY resistance imposed by the spring 16,
and during this movement force is transmitted
by the diagonally disposed metal' insert 1li to the
Hence, when the’driving arm 64 on the lever en
gages the associated, stop, the shoe is supported
in a newly adjusted position in proper spaced re
arm 62 of the lever causing arotation of the lever 4.0 lation to the drum,- ready forrfurther‘braking
operations.
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_about its fulcrum point, the pin 56, so that upon
conclusion of a braking operation and return of
Extremely small pressure is required to move
the shoe to retracted. position the lever engages
the blocks 66 inwardly; whereas, outward move
the retractile stop and supports the shoe in
ment is inhibited due to the frictional resistance
proper spaced relation tothe drum. Because of 45 imposed by the spring 16, and movement ofthe
the wedging action on the block between the wall
block when the brake is at rest is inhibited due
14 of the shell and the diagonally disposed metal
to the wedging action on the block between the
side 10 of the block, retrograde movement of the ' wall 14 of the shell and the diagonally disposed
block is inhibited. 'I'his is of vital vimportance
metal side 1U of the block; hence, the tension of
because of the tendency to maladjustment of the
the spring 32 connecting the shoes does not re
brakes due to the snapping action of the retrac
suit in maladjustment of the block.
tile spring 32 connecting the' shoes upon release
While this invention has been described in
of the brake at the conclusion of a braking oper
connection with certain specific embodiments,
the principle involved is susceptible of numerous
To reduce wear on the drum to the minimum,
other applications that will readily occur to per
.' the adjusters are Larranged in reverse position
sons skilled in the art. The invention is, there-with respect to one another so that in a given
fore, to be limited only as indicated by the scope
ation.
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brake structure the wear on theïdrum` may be
spread over substantially twice the area of a
drum structure wherein adjusters are arranged
in diametrically opposite position to onemanother.
This has another highly important advantage in
that the adjusters may be alike in structure and
accordingly the cost of production may be greatly
reduced.
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Wear on the drum is further and very mate
rially reduced by the introduction of a drum en
gaging member of the character of the block 66.
This block is made from impervious non-fric
tional material preferably a ceramic of ilne tex
ture, durable, high compressive strength, sub
stantial, and wear resistant. In practice, the
face of the block engaging the drum becomes im
pregnated with fine metallic particles and this
results in polishing the face of the’block to such
of the appended claims- I claim: i
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1. A brake comprising a movable member, a
friction lelement for cooperation therewith,v a
stop for the friction element, a member carried
by and movable transversely of the friction ele
ment having a side angularly disposed to the path
of movement of the member, a support on the
i friction element for the member, and a lever ‘piv- -
.oted on the friction element having a part en
gaging the angularly disposed side of the mem
ber and another part for cooperation with the
stop, said support providing a bearing‘for the
lever pivot.
2. A brake comprisinga movable member, a
friction element for cooperation therewith, a stop
for the friction element, a member adapted to
engage the movable member carried by and mov
w...
2,282,620
c
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able transversely of the friction element having
a part angularly disposed to the path of move
viding a bearing for the lever fulcrum and hav
ing means for frictionally clamping the member
ment of the member, a lever fulcrumed on the
friction element having a part engaging the an
to the friction elements.
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6. A brake comprising a rotatable drum, a fric
tion element for cooperation therewith, a re
gularly disposed side and another part for coop
eration with the stop, a shell fixed to the friction
element housing the transversely movable mem
tractile stop for the friction element, a member
carried by and movable radially relative to the
ber and the lever fulcrum, and spring means
within the shell holding the lever and member
friction element having a part adapted for co
operation with the drum andV another part an
toward the friction element.
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gularly disposed to the path of movement of the
3. A brake comprising a rotatable drum, a fric
member, a support for the member, and a, lever
tion element for cooperation therewith, a stop
associated with the friction element, a drum
engaging member carried by and movable trans
versely of the friction element having a side
angularly disposed to the path of movement of
the member, a support for the member iixedly
the short arm of the lever abutting the member
to provide for slidabie movement of the mem-.
fulcrumed between the friction element >and sup
port having arms of different radii, the end of
ber on the support.
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7. A brake comprising a movable element, a
friction element for cooperation therewith, an
adjustable retractile stop for the friction ele
ment, a member carried by and movable trans
operatively abutting the member and having its
versely of the friction element, a lever fuicrumed
opposite end cooperating with the stop, said
on the friction element adapted tor cooperate
member being movable along the support.
with the ‘movable element and having apart
4. A brake comprising a fixed support, a ro
angularly disposed to the path of movement of
tatable drum associated therewith, a friction ele
ment on the support having a lining for co 25 the member, a shell on the friction element shel
tering the member and lever fulcrum and con
operation with-the drum, a retractile stop for the
stituting a support for slidable _movement of the
element, a drum engaging member of impervious
member transversely of the friction element, said
material carried by and movable transversely on
lever having one part engaging the stop and
the element having a side angularly disposed
to the path of movement of the element, a lever 30 another part engaging the angularly disposed
part of the member `holding the member toward
fulcrumed on the friction element, a driver on
secured on the friction element, and a lever ful
crumed on the friction element having one end
the lever adapted to engage the stop, an arm
forming _part of the lever bearing on the mem
ber, a shell iixed to the friction element housing
the member and the lever fulcrum, and springs
acting independently upon the lever and the
member holding them frictionally against the
friction element.
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its support on the shell.
8. A brake comprising a fixed support, a ro
tatable drum associated therewith, a friction ele
ment on the support for cooperation with the
drum, a retractile stop for the friction element,
a shell fixed on the friction element, a member
`housed within the shell and carried by and mov
y able transversely of the friction element and
5. A brake comprising a movable member. a
~ friction element for cooperation therewith, a stop 40 having a side slidabie along an inner wall of
the shell, said' member havingl a side cooperat
for the friction element, a member carried by
ing with the drum and a part disposed diago- „
and movable transversely oí the friction element
nally to the path of movement of the member
having a side diagonally disposed to its other
transversely of the friction element, and a lever
side, a lever fulcrumed on the friction element
having a part contiguous the diagonally disposed 45 fulcrumed on the friction element Within the
shell having a part abutting the diagonally dis
side of the member, and another part for co
posed side of the member and another part for
operation with the stop, and means âixedly se
cooperation with the stop.
cured on the friction element for supporting the
member in abutting relation to the lever pro
"ifka.n
ARVEY C. SWIFT.
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