Note: Descriptions are shown in the official language in which they were submitted.
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QUICK CONNECT BR~I~E COUPLING
~ the Invention
This invention is directed to a coupling for connect-
ing a th~eaded rod to a second element having a bore pro-
vided ther~in and more specifically, to a coupling for
quickly connecting the threaded push rod of an air motor
to the clevis of a brake actuating lever and automatic
slack adjustor on a vehicle assembly line without the need
forany other tools.
~ore particularly, this invention is directed to a
coupling for quickly connecting the threaded push rod of
an air motor to the clevis of a brake actuating lever and
-automa-tic slack adjustor cf the type disclosed in U.S.
-Patent No. ~,949,840 which issued to J. C. Cumming, et al,
on April 13, 1976. Such a device will he~einafter be
referred to as a brake actu~ting lever which, for purposes
- of this invention, will be used to describe a brake
actuating lever that includes an automatic slack adjusting
mechanism as well as a brake actuating lever without an
automatic slack adjusting mechanism. Other brake adjust-
ing levers of the type with which the present invention
may also be utilized are described in United States
Patent Nos. 3,507,369, 3,526,303, Re. 26,965, 3,121~478,
3,351,164 and 3,371,755.
The brake actuating levers which the present inven-
tion is particularly directed are utilized primarily in
a rotary cam actuated internally expanding brake assembly.
121~
rhe brake actuating lever i.s splined at one end to a shaft
which ratates the cam and the other end is connected by
means of a clevis to the push rod of an air motor. '~ar-
ious connections have been used between the threaded push
rod of the air motor and the clevis. In one conventional
connection the threaded push rod is threaded into a tabbed
bore provided in the clevis and upon adjustment to provide
the proper length, a locknut is threaded down and seated
tight against the surface of the clevis to preven~ loosen-
ing of the push rod. This requires rotary movement ofthe push rod relative to the clevis or the clevis relative
to the push rod and may require either removing the clevis
from the brake actuating lever or the push rod from the
air motor. Removal or disassembly of component parts, of
course, requires whatever additional steps may be necessary
to reassemble those parts at the point of installation
on the vehicle assembly line.
One approach to avoid such disassembly has been to
provide both a locknut and an externally threaded ferrule
or yoke adaptor to the threaded push rod. During assembly
the push rod is brought into juxtaposition with a threaded
bore provided to the clevis. The yoke adaptor is threaded
to the bore in the clevis and then the locknut is tighten-
ed against the yoke adaptor to prevent disassembly during
service. This avoids the need to disassemble parts of
the brake actuating lever or the air canister) but it
still requires the use of tools in tightening two sep-
arate nut members in a relatively confined space on a
vehicle assembly line.
The present invention avoids certain of the foregoing
problems of the prior art by providing a coupling for
quickly connecting a threaded push rod to the clevis
of a brake actuating lever which comprises the combinat~on
of a collar having an internal bore threaded for engage-
ment with the push rod, a head at one end of the collar
and a recess forming a shoulder spaced from the head,
latching means carried by the clevis and biased into
a first position extending internally of a bore provided
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to the Glevis and latch displaeing means carried by the
collar adjacent to the shoulder. During assembl~ the
latch displacing means serves to displace the latching
means upon axial inserti.on of ~he collar into the bore
and the latching means returns to its first position and
engages the shoulder provided ~o the collar to prevent
withdrawal of the collar from the bore.
In the preferred embodiment, the latching means is
a spring carried by the clevis and the collar is comprised
of a cylindri~al body hàving a head at one end, a tapered,
conical surface at the other end and a spring engaglng
groove extending circumferentially around the cylindrical
body intermediate the head and the tapered, conical sur-
face. Upon insertion o~ the collar to the bore provided
to the clevis, the tapered, conical surface displaces
the spring latching means until such time that the spring
latching means is biased into the spring engaging groove
there~y preventing withdrawal of the collar from the bore.
Brief_Description of the Drawings
In the drawings wherein like reference numerals
refer to like parts:
Fig. 1 is a side elevation showing an assembly of a
threaded push rod to the clevis of a brake actuating
lever;
Fig. 2 is a top plan view, partly in section, showing
part of the assembly of Fig. l;
Fig. 3 is a side elvation of the collar shown in
Fig. ?;
Fig. 4 shows another element of the assembly of
30 Figs. 1 and 2;
Fig. 5 is a top plan view similar to Fig. 2 showing
an alternate embodiment of the invention; and
Fig. 6 is a sectional view taken along the line 6-6
of Fig. 5.
Description of the Pre_erred Embodiment
In Figs. 1 and 2 the present invention is shown in
the form of an assembly of a threaded push rod connected
to a cy].indrical bore provided to the clevis of a brake
8~7~:~
~,
actuating lever. With reference to Flg. 1 there ls shown an
alr motor 10 secured to a plate 11 whlch ln turn is rlgidly
secured to a brake support or directly to a vehicle axial.
A push rod 12 extending from the alr motor 10 is connected to
~he clevis 14 which is pivotaLly connected to the brake
actuating lever 15 by means of a pin 16 and cotter key 18.
The brake actuating lever 15 in turn is splined to the rotary
actuating shaft 19 of a cam brake assembly not sho~n.
The brake actuating lever 15 ls described in greater
detail in U.S. Patent No. 3,949,840 but consists essentially
of an elongated housing forming a lever 20 having a worm
gear 21 at one end. The worm gear 21 is internally splined
for connection to the rotary actuating shaft 19. A worm,
provided internally of the lever 15, engages the worm gear
21 and is connected to a rod 22 by means of an automatic
adjusting mechanism not shown. The rod 22 is pivotably
connected to the end of the clevis 14 by means of a pin 24
and cotter key 25. Air supplied to the motor 10 extends
the push rod 12 thereby rotating the brake actuating lever 15
cloc~wise about the rotary cam shaft 19 to the position shown
by the phantom lines. When the air pressure is released from
the motor 10 the assembly returns to the position shown in
Fig. 1. In the event the arcuate movement of the brake
actuating lever 15 is greater than some predetermined movement
considered satisfactory for normal running clearance, the
automatic adjusting mechanism will rotate the worm, the worm
gear 21 and the rotary actua-ting shaft to a position providing
the desired running clearance between the brake shoes and a
surrounding brake drum.
The coupling between the push rod 12 and the clevis 14
is best shown by Fig. 2. The clevis 14 is provided with a
cylindrical bore 26 having a recess in the form of a groove
28 extending circumferentially around the internal cylindrical
wall of the bore. A split spring ring 29 such as that shown
by Fig. 4 is provided to the groove 28. The internal diameter
of the split spring ring 29 is slightly less than the internal
~.'
diameter of the bore 26. A locknut 27 and a collar 30 such
as that shown by Fig. 3, are threaded to the push rod 12.
The collar is comprised of a cylindrical body portion 31
having a hexagonal head 32 at one end, a conical surfa~e 34
at the other end, and a groove 35 extending circumferent-
ially around the cylindrical body 31 intermediate the
hexagonal head 32 and the conical surface 34. The conical
surface 34 is tapered to gradually increase to the diameter
of the cylindrical body 31 of the collar 30 and the groove
provides a shoulder 36 adjacent the conical surface 34. The
split, spring ring 29 is carried by the clevis groove 28 and
extends partly into the collar groove 35 thereby providing
an interference fit between the clevis bore 26 and the
collar 30. Any attempt to axially withdraw the collar 30
from the bore 2~ will cause the shoulder 3~ of collar groove
35 to engage or abut the split, spring ring 29 which
prevents further movement or axial withdrawal of the collar
30 and push rod 12 from the clevis bore 26.
On a vehicle assembly line, the air motor 10 and the
brake actuating lever lS may be provided to the frame or
their respective related components at different points in
time and/or at different locations on the line. The motor
10 and the actuating lever lS may be obtained from different
sources and the brake actuating lever lS may be provided to
the OEM as an integral part of a rotary cam actuate brake
assembly. In any event, the present invention provides for
a ~uick connection of the air motor push rod 12 to the
clevis 14 of a brake actuating lever 15 at any predeter-
mining point on the assembly line.
In practice, the locknut 27 and collar 30 are threaded
to the push rod 12 but only to the extent that the push rod
12 is flush with or extends only slightly from the tapered,
conical end of the collar 30. The locknut 27 may be
tightened to the collar 30 at that time. Then at the
appropriate location on the assembly line, the push rod and
collar 30 are manually, axially inserted in
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7~ii
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the cl.evis bore 26 to effect the desired connection.
Upon axial inser~ion of the collar 30 the tapered,
conical surface ~4 connects the split, spring ring 29
and expands that ring Eorcing it back into the groove
28 provided to the bore 26, thereby permitting the
cylindrical body portion 31 of the collar to slidably
pass the expanded spLit ring un~il the collar groove 35
becomes aligned with the groove 28. At this point, the
split, spring ring 29 will snap into the groove 35 and
provide an interference fit between the grooves 28 and 35
thereby preventing withdrawal of the collar. Once a3sem-
bled the collar 30 cannot be removed from the clevis 14
but the push rod 12 may be removed for normal service pur-
poses by loosening the locknut 27 and rotating the hex-
15 agnol head 32 of the collar 30 to back the push rod 12
out of the collar.
An alternate embodiment is shown by Figs. 5 and 6.
In Figs. S and 6, elements identical to those previously
described are identified by the same reference numerals.
The clevis of the embodiment shown in Figs. 5 and 6
is slotted across the top and bot~om as shown at 40 and
41 to provide access from the exterior of the clevis
to the interior of the cylindrical bore 26. ~he clevis
14 is also drilled and tapped at 42 to accommodate a
25 machine screw 44. A spring 45, best shown in Fig. 6 is
f.ormedat its midpoint with a loop that fits ~round the
shank of the machine screw 44 and is trapped between
the head of the screw and the clevis body proper. The
ends of the spring 45 extend through the slots 40 and
41 across the body of the clevis and are formed with
deten~s at 46 and 48. The detents 46 and 48 project
into the cylindrical bore 26. During assembly a lock:nut
27 and a collar 30' are threaded to the e~d of the push
rod 12 in the same manner as previously described for
~5 the embodiment of Figs. 1 and 2. The collar 30' is
tapered or chamferred at the end 34'. As the push rod
12 and collar ~O' are axially inserted to the cylindrical
bore 26, the tapered outer end 34' of the collar contacts
.
-1-
~he detents 46 and 48 provided to the spring 45 and ex-
pands ~he two legs of the springs 45 out into the slst
40 and 4L until the groove 35' provided circumferentially
around the collar ~0' is aligned with the slots 40 and 41.
When the groove 35' becomes axially aligned with the
slots 40 and 41, the detents 4~ and 48 are biased into
the groove 35' and prevent the collar 30' from being
axially withdrawn from the bore 2~.
The springs 29 and 45 of the two described embodiments
thus constitute latching means carried interiorly of the
cylindrical bore provided to the clevis which are dis-
placed by the tapered, conical surface provided to the
collar 30 or the tapered end provided to the collar 30'
to pass a portion of the cylindrical body of each respect-
ive collar until the grooves provided to the collar alignwith the spring biased latching means.
Both embodiments provide the desired quick connect
assembly of a push rod to a clevis. The embodiment
of Figs. 1 and 2 offers the additional advantage tha-t
the split, spring ring can be provided internally of the
clevis bore without requiring an additional element such
as the machine screw of the Figs. 5 and 6 embodiment
which might be accidentally removed or lost during ser-
vicing.
The invention may also be embodied in other specific
forms without departing from the spirit or essential
characteristics thereof. The foregoing description is,
therefore, to be considered as illustrative and not
restrictive, the scope of the invention being defined by
the appended claims, and all changes which come within
the meaning and range of equivalency of the claims are
therefore, intended to be embraced thereby.
