Note: Descriptions are shown in the official language in which they were submitted.
DUA~!3AU ASSEMBI.Y FOU CONNLC`rlNC RAIL _~RS
BAC G~OUND 01 Tlll lNVCNr1.0N
lhis invention relates in general to connection
systems for rail cars and, in particular, to ;mproved
drawbar assemblies.
More specifically, but without restriction to the
particular use whicll is shown and descr;.becl, this inven-
tion relates to an improved drawbar assembly capable of
reducing slack and wear oE components during operation of
railway cars. This system of the invention further dimin-
ishes the weight of a coupling assembly needed for satis-
factorily connecting rail cars with a resultant savings in
cost and economy oE operation. The drawbar assembly inven-
I tion employs a dual wedge arrangement positioned immeùiately~head of the rear lugs of a car ~ to reduce slack. An
elastomeric means is employed resiliently to cushion buff
forces to a limil:ed extent and to aid in curve negotiability.
Conventional coupling systems for rail cars have
long employed standard draft assemblies having couplers,
yokes and draft g~ears, as is well known. Known coupler
designs suffer from several problems associated with the
heavy impact loads which normally occur in train operations.
The knuckles oE a conventional coupler are subject to brealcage
and detrimental slack, causing wear between the components
and maintenance problems. In addition, conventional coup-
ling systems are unduly heavy and include a multitude ofcomponents contributing to undesirable car costs and weight.
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In some types of rail cars, however, it is not necessary
for the cars to be uncoupled frequently in service,
particularly in long mileage operations. Such cars may include
bottom dump coal cars, intermodel articulated cars with single
axle trucks, or other cars not requiring tha capability of
conventional couplers. One alternative to normal coupling
system components has been to employ a simple bar between cars,
but such arrangements have been subject to numerous
deficiencies in service due to the Pnormous draft and buff
forces encountered. Attempts to modify known drawbar designs
to provide satisfactory operations have not been wholly
successful. Prior clrawbar systems present the additional
problems of wear, poor response in curves, and a lack of
versatility for accommodation by both existing and new rail car
sills, among many shortcomings.
SUI~ARY OF TEIE INVENTION
The problems of the prior art are overcome by the
present invention which provides a drawbar assembly for
interconnecting a pair of rail cars, the assembly comprising
in combination a drawbar having a pair of opposed ball ends
retained in sockets formed in the respective sills of ad~acent
rail cars and securement means for removably affixing the ends
of the drawbar in their respective sockets. Each socket
comprises a first movable follower block having a concave
surface for receiving one of the ball ends, an elastomeric pad
abutting the first follower block for providing limited
cushioning of buffing forces applied to the drawbar, a second
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movable follower block abutting the elastomeric pad, and a
double wedge assembly including a stationary wedge and a
gravity wedge abutting the second follower block. The
elastomeric pad may be generally flat-sided and reinforced by
a plurality of metal plates embedded therein.
The present invention provides an improved drawbar
assembly for reducing slack in a railway coupler. The
components in the drawbar system are maintained in a near
slackless configuration in response to draft forces, while
subject to a limited resilience or cushioning in buff for
accommodating manufacturing variations in mating surfaces and
permitting a more freely pivotal drawbar. The drawbar
connection of the application reduces wear and maintenance
problems in service and attains economical operation by virtue
of a reduction of cax weight by a double-wedge design that
cooperates with an elastomeric pad in a novel and improved
manner
DESCRIPTION OF THE DRAWINGS
Further features of the invention and advantages
accruing therefrom, will be apparent from the following
description of a preferred embodiment of the invention; which
is shown in the accompanying drawings with like reference
numerals indicating corresponding parts throughout, wherein:
FIG. 1 is a side elevational view of the drawbar
assembly of the invention;
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FIG. 2 is an enlarged fragmentary top plan view
with the lower portion thereof shown in horizontal section;
and
FIG. 3 is a fragmentary vertical sectional view
taken substantially along the line 3-3 of Fig. 2.
DESCRIPTION OF TLE PREF~RRED EMBODINENT
Referring now to Figs. 1-3, there is illustrated
the improved drawbar assembly of the invention for coupling
rail cars, such as bottom dump unit train cars and the like
to replace conventional automatic couplers. The drawbar
assembly of the invention is generally designated by
reference numeral 2 and is mounted within a typical draft
sill casting 4 or other sill cons~,ruction. The drawbar
assembly 2 includes a symmetrical drawbar 6 having a pair
of enlarged heads 8 interconnected to a necked down portion
6', Fig. 1.
Inasmuch as the construction of the drawbar
assembly 2 is identical at both ends, details of the
construction of the invention are described with reference
to one of the ends in Fios. 2 and 3. In the plan view of
Fig. 2, the drawbar head 8 includes an outermost portion
10. A pair of side surfaces 12 are inclined inwardly and
terminate with a spherical buffing surface 14. As best
seen in Fig. 3, the top and bottom surfaces 16 of the head
are flat and a key or pin opening 18 extends laterally
through the drawbar head 8. A drawbar pin or key 20
A. projects through the drawbar head 8 for attachment to the
,i draft sill 4. As can be seen
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in Fig. 3, the pin opening 18 has nn elongated longitu-
clinal configurntion s;gnificanLly greater in length than
the diallleter c)[ pin 2() clncl a vertical heiglli slightly
greater. Ihis .shape permits Ihe drawbar 6 to pivot freely
S in curves.
The pin 20 is retained on the draEt sill casting
4 by means oE a pin retainer fabrication 22 disposed on
each end of Lhe drawbar p;n 20, as best shown in Figs. I
and 2. The pin retainer fabrication 22 inc].udes an inner
plate 24 upon wllich a rib-like supporting structure 26 is
welded. An opening is provided through plate 24 in which
a sleeve or tube 28 is welded to the plate 24. The pin 20
is retained at each end by means of a pin retniner and
cotter pin 30.
A pocket 32 opens into pin opening 18 and receives
a pin bearing block 34 which is resiliently mounted by means
oE a pair of a lower and upper spring 36, as seen in Fig. 3.
The pin bearing block 34 possesses a concave surEace 40
arranged to contact a portion of the periphery of drawbar
pin 20 and generally convex surface 34', as seen in Fig. 3.
The spherical bu:cEing surEace 14 oE the drawbar heacl 8 is
arranged to cooperate with the concave surEace 42 provided
in a cast follower block 44 movably positioned adjacent
the end oE the drawbar 6. ~n elastomeric pad 46 is mounted
on the opposite side oE the Eollower block 44 from the encl
of the drawbar 6. The elastomeric pad 46 is formed with
an elastomeric rnaterial 48 sandwiched between a pair of
... _ . .. .. . . . . . . . _ _ .. . _ .
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end plates 48a and reinforcecl by i.nternal metallic plaLes
48b. Tlle elastomeric pad 46 acts to respollcl to buffing
forces arld prc)vitle a cusllioning errect, with tlle pacl bring
disposed between the cast follower 44 anr1 a rllovable rear
Eollower block 50. The elastomeric pad 46 allows [or
better pivotillg of the drawbar and alltomatically compen-
sates [or surrace variations of rnating surfaces, sucrl as
caused by irregularj.ties in the surfaees of the ball and
mating parts.
The rear follower block 50 is supported between
the elastomerie pacl 46 and a wedge assembly. The rear
wedge 54 whieh has an inclined faee 56 eooperates with an
oppositely oriented, generally ;dentieal gravity wedge 58
having an inelinecd faee 60 and being relatively movable to
take up slaek. Thus, the wedges aet to remove slaek in
the drawbar eonneetion by the cooperative action of the
two inelined wedge surfaees 56, 60.
The inboard wedge 54 forms a poeket 62 with rear
follower block 50 in whicll the gravity take-up wedge 58
operates. The design of the gravity wedge 58 provides a
slope adequate to insure that the wedge 58 will have a
downward resultant force so it will tend to move down under
all conditions, including buff. The wedges will also com-
pensate for a significant amount of wear among the rnating
parts. The elastomeric pad 46 provides relief and resulting
reduction in frietion between rllating surfaees when movernent
takes plaee, sueh as in pivoting.
~s~
While tlle invention has been described with reE-
erence to a prcEerred elllbodiment, it will be understood
by tho~se skilled in the art that various cllallges m.ly be
made and e(lu iva I en ts may be subs t i tu ted f or e I emen ts
5 thereoE wi thout departine Erom the scope oE the invent;on.
~n addition, m.lny modiEications may be made to adapt a
particular situation or material to the teachings oE the
invent;on wi thout departing Erom the essential scope
thereoE~ ThereEore, it is intended that the invention
10 not be limited to tlle particular embodiment disclosed as
tlle best mode contemplated Eor carrying out this inven-
tion, but tllat the invention will include all embodiments
Ealling witllill the scope oE the appended claillls.
