CA2055412C - Railway truck side bearing - Google Patents

Abstract

A side bearing for a railway truck and car body assembly including one or a plurality of elastomeric bearing elements, confined at given locations in a side bearing carrier and vertically-extended rigid abutments disposed adjacent the elastomeric element(s), and a roller or similar rigid bearing element disposed to be free rolling within defined limits with respect to the elastomeric elements.

Description

2055~12 BACKGROUND OF THE INVENTION

A railway r-reight car commonly includes a car body supported on the center plates of a pair of longitudinally spaced trucks. The coned wheels of the trucks engage the respective rails of a railway -track and the trucks travol a generally sinuous pa-th along -tangent track as they contirlually seek a centered position under the s-teering influence of the wheel conicity. In traveling such a sinuous path, a railway truck will oscillate laterally and yaw cyclically with respect to the car body about the vertical axis defined by the vertical center line of the truck bolster center plate. A railway truck also will yaw or rota-te quasi-statically with respect to the car body in negotia-ting curved track.

As a result of such lateral truck oscillation and cyclic yawing, unstable -truck hunting responses can develop if tl1e frequency of the cyclic mo-tion approaches resonance.
Reference is made hereby to prior U.S. patent 3,957,313 for f-urther detailed explanation of railway vehicle truck huntillg phenomena, and such explanation is heret)y incorporated herein by reference.

Railway car body rock and roll is another problom in railway car stability that is related to the truck hunting phenomenon. As the trucks of a railway ear negotiate their sinuous path of travel along the railway track, the car~ body 20~5412 will rnove laterally in concert wi-th the cyclic lateral movemcnt of the truck center plates. The loaded or heavy car readily tolerates this lateral oscillation; however, the empty or light car body may be driven to roch la-tcrally from side to side. As with known truck hunting pllenomena, this lateral rock and roll cmp-ty car body mo-tion can also bc driven by resonant coupling to destructive extremes.

~ailway truch side bearings have long been utilized to providc support for a car body with respect to a truck la~erally outward o~ tho truck center plate. ~uch support is nccessary not only in view of the tendency of an ernpty car body -to roch from side to side as a result of the force inputs of hunting or rock and roll phenomena J but addl tlonally by the negotiation of trach curves and the superelevated track encountered in curves.

Olacr Conventional sidc bearings have includcd roller bearinc3s carried ~or rolling movcment longitudinally wlthin 2~ an clorlcJatcd cagc or carrier mounted on a railway truck bols-ter. The roller ex-tends above tlle uppermost extent of the open top of the carrier for rolling engagernent with a wear plate carried by the car body. Such side bearings are able to support a car body with respect to a truck bolster laterally outward oF thc truch center plate while at thc same time permitting the bolster, and therefore the truck, the rrccdom to rotate with respect to the car body as is necessary to accommodate the normal truck movement along both tangent and curved track as above described.

rhe art has also contemplated railway truch si(~e bearinys which serve not only to suppor-t a car body with resp~ct to a -truck bols-ter cJuring rel~tive rotational movement tllerebetween, but in addition to dissipate energy throu~h frictional engagement between the car body wear plate and a bearing element whereby the requisite rotational freeciom of the truck with respec-t to the car boc~y is maintained while a degree of restraint is also provided as a means to control and limit destructive huntin<J responses.
Still further, the prior art has contemplated the use of elastomeric elements to cushion the vertical loading of a car body on a truch bolster exerted -through the side bearing struc-ture. Still other prior side bearings have eontemplated roller bearing struc-tures with self-centering rollers.

Among the prior side bearlngs hnown in the ar-t as a~ove characterized are those disclosed in U.S. patents 1,~3l,926, 2,30l,37Z, 2,754,763, 3,255,712, 3,295,463, 3,313,245, 3,493,221, 3,513,943, 3,556,503, 3,623,464, 3,670,661, 3,719,154, 3,796,167 and 4,359,0~9.

In some prior side bearings, the desired function was purcly to minimize friction, as in roller side bearings. In others, friction elements were intentionally in-troduced to provide bo-th support and rotational freedom for the car body 20~S412 with rospect to the truch bolster, as well as rotational restraint through the frictional dissipation of energy. The above-ci-ted patent 4,~59,0~9 is one example of such an energy dissipating side bearing.

Other more recent prior art side bearinys such as -that disclosed in U.S. patent 4,090,750 have contemplated tho use of bearing elemen-ts formed of elastomoric columns an~
upstanding rigid abutments which are engageable with a car body wear plate to provide both vertical support and relative ro-tational freedom for the car body with respect to the bols-ter, as well as a friction interface between the elastomeric columns and the car body wear plate to provide frictional energy dissipation upon rolative rotation of the car body with respect to -the bolster.

Still other recen-t prior art side bearlngs such as those disclosed in U.S. patent 4,030,016 and 3,957,31~, combinc elastomeric columns to provide support and trlc~lonal energy dissipation as above characterized, and rollcr elemen-ts to limit the magnitude of vertical de~lection of the elastomeric elements by providing a solid stop beyond which the car body wear plate cannot move vertically downward. The roller elements provide, at the limit of vertical motion of the wear plate downward toward the bolster, a range of relative rotational freedom for the car body with respect to the bolster without significantly increasing frictional restraint with greater side bearing loaditlg beyond that afforded by the elastomcric columns alone.

Another truch bearing structure, not so recent, is disclosed in U.S. patent 3~ 2 as a ball bearing elcrnent disposcd in a downwardly concave cup which iS in turn resiliently supported by an elastomeric ring elcmcnt.

The present invention con-templates a novel and lmproved rallway truck side bearing structure especially well sui-ted for use in railway truck and car body com~lnations unhnown when many of the above cited prior bearings were dcvelopod. Others of the above prior slde bearings, al-though developed when the more modern truch and car body combinations were known and could be suitably adapted for use -thereon, were nevertheless not specifically developed for use with such truck and car body assemblies and their design and development did not contemplatc the oper<lting conditions and problems posed by modern car conFigurations.

More speciFically, certain newer types of railway cars utilize articulated couplings between pairs oF adjacent car platforms that share a common intermediate truch havirlg a flat center plate bearing. These and other car conf-lyurations often may have longer spacing between adjacent truchs; that is, the car platform lengths, and therefore the inter-truck spacing, may be greater than in convel1tional cars. S-tacking of containerized loads and similar transport modes for these and other cars, often characterized as intermodal cars, has resul-ted in loaded cars with extremely high centers of gravity, for example as much as 110 inches above the track.

In these and other car configurations, the role of the side bearing in supporting the car body with respect to the bolster has been al-tered dramatically. For example, in very high center of gravity loaded cars, most particularly the double stacked container configurations, the loaded car body center of gravity is located well above the articulated conrlec-tor by which at least one end of the car body is supported. Even if the opposed end of -the car body is supported by its own -truck on a conventional flat center pla-te bearing, and even if the lading is centered on the car platform, the torsional stiffness of the car platforn- and containerized lading may be insufficient to keep the car body end that is suppor-ted in spherical bearing segments from learling continuously to one lateral side or -the other for relatively extended periods of car travel. If the lading is off-center, or in such operational circumstances as the traverse of track curves, extended periods of large magnitude side bearing loading may be virtually unavcidable.
Accordingly, the corresponding side bearing may be required to support a much greater than normal load through extended periods of car travel. Thus, the side bearing must accommoda-te controlled rotational freedom between the truck 20~5412 an~ the car body through an angle equivalent to -the maximum relative rota-tion -therebetween and this in turn requires maximum longitudinal rolling freedom for the roller bearing element. The maximum relative rotation between a car body and a truch in normal operation may be as great as the relative rotation experienced from a short radius left hand turnout to a similarly short radiused right hand turnout although more typically the range of relative truch-to-car body rotation which -the side bearing must accommodate would be that experienced in the spiral or entry portion of a trach curve.

~he oxtendea platform lenyths of some modern cars also can require a greater range of rela-tive rotational freedom between the truch and the car platform because a longer platform requires a greater angle of relative rotation between the platform and the respective truchs to ne(~otiate curved track of any given radius. Still further with groater car load capacities and higher centers of gravity there is impetus for designers to place the side bearings at a greater radius from the truck center plate or articulated connec-tor to maximize the lateral moment arm of the side bearing with respect to the center plate bearing. This too increases the magni-tude of roller bearing movement needed to accommodate relative truck-to-car body rotation. An addi-tional design problem is that the geometric limitations of truck and car body design limit the physical size of the side bearing components that can be u-tilized in a given applicatior1. It is pre~erred under most circumstarlces to hccp tllc "footprint" oF a side beariny (i.e. the size of tl1e car body wear plate required to cooperate with the sidc beariny) as small as possible, even though moderr1 car desiyns often call for increased rather than reducecJ beariny load capaci-ty and ranye of movement.

BRIEF SUMMA~Y OF THE INVENTION

Ihe prcsen-t invention contemplates an improved slde bearing s-tructure which is especially well suited for use wi-th intermodal cars and similar modern car confiyurations haviny larye load capacities, high centers o~ gravity, lonyer truck spacing, and other design features to which some prior side ~earinys miyht be less well suited in the tash of optimizing the dynamic performance of the car. Tl1e inve-ltion con-templa-tes yenerally a railway truch side bear-iny assembly which is preferably adapted to be confir~ed within a gcnerally conventional, standard railway truck side bearing housiny or carrier and including a-t leas-t one upstanding elastomeric bearing element and a longitudinally adjacent spacer member disposed within the carrier. Thc spacer member includes at least one upstandiny abutmcnt which longitudinally confines a correspondiny elastomeric z5 column, and a generally upwardly facing elongated surfaco to receive a rigid bearing element such as a roller tl1erein.
The roller is provided a range of free rolling movcment longitudinally of the spacer member between stops or limits defined by longi-tudinally spaced portions of the spacer rnember.

rhe range of free movement for the roller can be mado su~ficient to accommodate -the greater range of relative rotary movement between a bolster and a car platform required in modern car configura-tions as discussed hereinabove without sacrifice of frictional energy dissipation capability provided by the elastomeric columns.
Tllis is so in part because the upstanding abutments of the spacer member can extend upwardly above the uppermost extent of -the bearing carrier or housing and adjacent an upper portion of a corresponding elastomeric column to longitudinally bu-ttress and confine the elastomeric element sufficiently that it does not bend longitudinally over the top of the confinirlc3 abutment.

Accorcingly, surface con-tact between tlle upwardly facing bearing surface of the elastomeric colùmn arld tlle car 2U body wear plate is maintained more uniformly anc the full benefi.t of the shear restrain-t and frictional energy dissipation at the elastomer-to-rigid wear plate interface thus is realized. As a result, a smaller section thickness of elastomer, especially in the longitudinal direction, may be employed to attain the same levels of performance as regards shear restraint as in prior elastomeric side bearings requiring larger section elastomeric columns.
Thus, without sacrificing the desirable control capabilities of <3 laryer section elas-tomeric column, an increased range of longi-tudinal roller mo-tion is made available in a side bear:ing llousing of given dimensions.

It is there~ore one object of the prosent inverltiorl to provide a novel and improved railway truch side bearing;

Another object of the invention is to provide an improved railway truck side bearing comprised of at least one upstanding elastomeric column bearing and a rigid roller or similar element whicll provides a rigid limit to vertical compression of the elastomeric column, and structure and method of partially confining the elastomeric column and maximizing the free rolling range for the bearing roller element.

Still another ob~ect of the invention is to provide, ~or use in a railway truck side bearing, an abutment or spacer element WhiCIl serves to partially confine an upper extent of an elastomeric bearing element and in addi-tion to elevate the rolling surface of a rigid roller bearing element above -the base of the bearing housing such tllat a smaller diameter roller than commonly employed may be utilized.

~hese and other objects and further advantages of tlle invention will be more fully appreciated upon consideration of the followin9 detailed description and the accompanyiny drawin(3s in which:

Fig. 1 is an end elevation showing a side bearing according to one presently preferred embodiment of the ins-tant invention and cooperating portions of a railway truck and car body;

Fig. 2 is a sectioned side eleva-tion of a side bearirlg tahcn on line 2-2 of Fig. 1;

Fig. 3 is a sectioned side elevation showing an alternative embodlment of the instant invcntion;

Fig. 4 is a sectioned side elevation showing anothcr alternative embodiment of the instant invention;

Fig. 5 is a sectioned side elevation showing still anotller alternative embodiment of the inven-tionj Fig. 6 is a sectioned side elevation similar to Fig. 5 and including representation of a car body wear plate to illustrate one operating condition for the illustrated side bearing;

Fig. 7 is a top plan view of anothcr alternative embodiment of the invention;

Flg. 8 lS a sectioned side elevation taken on line VIII-VIII of Fig. 7;

Fig. 9 lS a top plan view of a further alternative embodiment of the invention;

Fig. 10 is a side elevation, partially broken away, of still another alternative embodiment of the invention;

Fig. 11 is a top plan view of the embodiment of Fig. 10 with portions broken away;

Fig. 12 is a sectioned side elevation of another alternative embodiment of the invention;

Fig. 13 is a sectioned side elevation of another alternative embodiment of the invention;

Fig. 14 is a sectioned side elevation of a fragmentary portion of a side bearing showing a further alternative embodiment of the invention; and Fig. 15 lS a sectioned side elevation similar to Fig. 14 showing yet another alternative embodiment of the invention.

~horo lS gcnerally indicated at 1~ in Fiys. 1 and 2 a side bearing assembly which is carried atop a bolster 12 of a railway truck and is secured thereto as by thrcaded fasterlcrs 14 for cooperative interaction with the wear plate 2055~12 16 of a rail car body 18 supported by a center plate bearing portion 13 of bolster 12. Although this invention will be described with reference to a conventional truck bolster and center plate support system as in a known three piece truck, it will be understood that the invention may also be utilized in other car body support applications such as intermodal cars or other car configurations where adjacent car platforms are supported through the bearing segments, commonly spherical in form, of an articulated coupling that is supported on a truck, as well as alternative truck configurations such as single axle trucks. For application in a conventional three piece truck, other known components not shown include spring groups mounted in a pair of side frames to support the opposed longitudinal ends of bolster 12, and suitably journaled wheelsets which rest on tracks or rails to support each side frame of the truck.
The invention herein is directed primarily to side bearing assemblies such as shown at 10, and the balance of the truck and car body elements set forth hereinabove are well known in the art. Further detailed description of such elements thus is not necessary for understanding of the present invention.
The invention also contemplates in one preferred embodiment an assembly of side bearing components adapted to be received within a side bearing housing or carrier 20 of generally conventional design, or alternatively in a new and heretofore unknown side bearing carrier. The side bearing assembly 10 comprises the elongated bearing carrier or housing 20 having a pair of elongated, upstanding, laterally spaced side walls 22 and a pair of longitudinally spaced, upstanding end walls 24 which may be comprised of respective pairs of laterally rn/

adjacent, ir-turncd end flange portions of side walls 22.
For this and other bearing carrier end wall configurations, sl1im plates 26 may be assembled wi-th end wall portions 24 such -that uppcr portiors 2~ thereof overlie tl1e uppermost extcnt of end wall por-tions 24, and a lower cxtent 30 of each shim plate 26 extends adjacent an inner surfacc of the end wall portions 24, respectively, and downwardly into the confincs of carrier 20.

The carrier 20 further includes a longitudinally and laterally extending base por-tion 32 which, in conjunction with side walls 22 and end walls 24, fbrms an upwardly opening cavity 34 to receive and confine an assembly of side bearing elemen-ts.

It will be seen that si~e walls 22 and end walls 24 projcct upwardly to an uppermos-t extent which is at a un:iform elevation. Additionally, the upper exterlt 2~ of each shim plate 26 projects to an elevation above the uppcrmost exten-t 36 of the side and end walls 22, 24 for a purpose to be describcd hereinbelow.

Within the confines of space 34 is received an assembly of bearing elements comprised preferably of a pair of elongated, upstanding elastomeric columns 40, one received in each longitudinal end of space 34 adjacent a respective end wall portion 24 and in longitudinal abutment with the respective shim plate 26, an elongated spacer or abu-tmcnt member 4Z rcceived within space 34 longitudinally intermediate clastomeric columns 40, and a rigid bearing membcr such as a roller 44 is receivcd within spacc 34 intcrmcdiatc side walls 22 and within the confinemcnt of an upwarcily opening concavity 46 formed by abutment member 42.

Spacer member 42, also referred to alternatively as a saddle, includes a longitudinally extending base portion 4~
which rests upon an upper surface 50 of carrier base portion 1~ 32, a pair of upstanding end abutment portions 52 which are spaced longitudinally apart to reside longitu~inally inwardly adjacen. the respective elastomeric columns 40, and inte<Jral curved or radiused portions 54 which extend in~crmcdiatc base portion 43 and the respective abutment portions 52.

It ~ill be noted that abu-tment portions 52 ex-tend upwardly to an uppermost extent 56 which, lihe thc uppermost portions 2~ of shim plates 26, project above the upper extcnt 36 of tl-e side walls 22 and end walls 24 to an elevation preferably just slightly below the highest elevation of roller 44. Accordingly, upstanding abutments are providcd at an clevation above the highest lateral abutment provided by carrier 20 such that the relative rotational movement between bolster 12 and car body 1~ occurs at all load levels with reduced tendency for elastomeric columns 40 to bend longitudinally, and therefore reduced tendency for devclopmcnt of non-uniform loading of the elastomeric columns 4~ in compression. Moro particularly, rolative rotation between car body 1~ and bolster 12 results at all load levels in shear deformation of elastomeric columns 40 in the longitudinal direction and ultimate friction breah and longitudinal sliding of wear plate 16 on the uppcrmost surfaces 41 of elastomeric columns 40. Both the control provided by horizontal shear deformation of the elastomeric columns prior to frictional sliding between surfaces 41 and wear plate 16, and the energy dissipation achieved by frictional sliding movement between the surfaces 41 and platc 16 are optimized in part by abutmen-ts 52 which col)strain the elastomeric columns 40 -to remain esscntially upright under all operating conditions and load levels.

-l5 In prior side bearings wherein a relatively elonyated extcnt of an elastomeric column projectod above thc hiyhest loo(~i-udinal abutments arld was thererore relatively unconfirled in at least one longitudinal direction, relativc rotation of the bolster about a vertical axis with respect to the car body, with the car body wear plate engaging the side bearing elastomeric columns, produced in the lonyitudinally unconfined élastomeric columrls a tendency to bend longitudinally. This is espccially true of the -trailing or rearward elastomeric ~ column, reckoned with respect to the direction of lonyitudinal movement of the car body wear plate 16 with respcct to the side bearing assembly. Such elastomer column bendiny produces non-uniform loadiny across the surface 41 of the elastomeric elemen-t thereby siynificantly deyradiny the shear restraint available a-t the wear plate-to-elastomer interface. By providing abutments projecting upwardly, pre-ferably above the bearing carrier side and end walls, and especially for the longitudinally opposed sidos of the elastomeric element, improved longitudinal confinement of the elastomeric element enhances the uniformity of loading on the uppermost surface thereof. As a result, the shear restraint available at the wear plate-to-elastomer interface is of both greater magnitude and improved uniformity over that available wi-thout such longitudinal abutments.

Accordingly, che desired characteristics of sllear res-traint in the elastomer-to-wear plate in-terface can be achieved with elastomeric columns of smaller cross section than required in prior side bearings. Therefore, within -the confines of a given bearing carrier 20 more longitu~inal space is available betweon elastomoric element-s 40 by use of smaller section elastomeric elements to provido a greater longitudinal rolling range for roller 44. The side bearing thus can accommoda-te increased angular rotation between truck 12 and car body 1~.

rhe lnwardly facing surfaces ~0 of member 4~ provide rigid stops or lirnits for roller movement such that roller 44 will not laterally deform elastomeric elements 40 as it z5 rolls longitudinally to one extreme or the other in its longitudinal travel. However, it will be noted that the spacer member 4~ is free to move or rock longitudioally Witl respect to housing 20 so that when rollor 44 engages ono of 20~5412 surfaces 60, the member 4~ can roll or tilt slightly in the samc longitudinal direction by limited longitudinal compression of the adjacent elastomeric column 40. The member 4~ thereby provides a further increment of roller movement in the longitudinal direction and cushions the engagemen-t of the roller on the surface 60.

It will be noted that the uppermost ex-tent Or roller 44 projects above the upperrnos-t ex-tcn-t of the sidc walls 22 and cnd walls Z4, and additionally above the uppermost extcnt of the shim plate upper ends 2~. The roller 44 also projcc-ts above the uppermost projection 56 of the abutmcnt portions 52, although preferably only very slightly above.
Accordingly, whcn the loading on elastomeric columns 40 deforms -them ir- vertical compression to the solid con~ition whcrl-at plate 16 engages roller 44, plate 16 rcmains at all timcs clear of contact with side walls 22, end walJ.s 24, shirn plates 26 and abutment projections 56, and only a very mil1imal vcrtical exten-t of the elastomeric columns projccts abovc the uppermost extent 56 of abutments 52.

Inasmuch as one object of this invention is to providc, within the confines of a given bearing carrier, the neccssary longitudinal free rolling range for a rollcr bcaring element to accommodate the greater relative ro-tational movement between a truck and a car platform as must be accommodated in some modern cars, it will bc noted that an additional advantage provided by abutment member 4 is th<lt it elevates the rolling surface on which roller 44 is supported above the uppermost surface 50 of base 32.
Accoldirlgly, -the uppermost ex-ten-t of roller 44 projects further upward by an equal increment thereby permitting the use of a smaller diameter roller than could be otherwise employed, where the load limi-ts to be encoun-tered by the roller beariny permit. A smaller diameter roller occupies less of -the longitudinal rolling range available between tlle limits defined by the abu-tment member 4~ thereby providing further increased longitudinal free rolling ranye for the roller 44. Accordingly, the smaller diamoter roller allows the accommodation of larger ranges of relative angular rotation between a truck and a car body within the confines of a given side bearing carrier or housing 20.

Other embodiments of the lnvention are shown in Figs.
3 through 5. In Fig. 3 -the bearing assembly shown is essentially identical in most salient respects to tllat described hereinabove with reference to Figs. 1 and 2;
2~ however, the abutment member 62 is configured to include a base portion 64 which is of a concave configuration to provide a generally concave upper surface 66 on which roller 44 is supported. The roller 44 thus tends to be gravitationally self-cen-tering when in a free rolling state (i.e. not engaged by tlle car body wear plate) to ensuro that sofficient free rolling range in either longitudinal direction will be available upon contact of the roller 44 by the car body wear plate. It will be recalled that some 2055~12 modcrll cars with extremely high centers of gravity when loadcd will tend to lean over on one or the other of sidc bcarirlgs on a given -truck for rela-tively long periods of travcl. For any embodiment of this invention, the available frcc rolling space in either longitudinal direction for roller 44, when centcred, should be sufficient to accommodate the maximum relative truck to car body rota-tion which can occur under such circumstances.

A~dltionally, abutment member 62 is free to roch longitudinally within housing 6~ if the concave upper surtacc 7~ on wllich member 62 rests is of a larger radius -than the mating convex surface 75 of member 62. As member 62 rocks, -the upstanding abutmcnt at the lcading end thereof (with respcct -to thc direction of its longitudinal roching) comprcsscs the corresporlding elastomcric element 40. The rocking action of member 6Z presents to thc roller a progressively lower angle of inclination on surface 66 as the roller 44 moves up the incline of surface 66 when displaced fron- its ccntcred position. Without the rocking capability for member 62, as the roller moves to one side or the other from its centered position it rolls up the centering incline, and the side bearing thus is lifting the entire weight supported thereon vertically upward. This increase in the vertical loading on the side bearing roller, increases the directly proportional horizontal restraint be-twcen the roller and body plate 16, which is undesirable;
however, such lif-ting reduces elastomer compression nousin(J 6~ benea-th the abutment member 62.

Fig. 4 discloses anotl1er alternative embodiment of the invention similar in many salient respects to that described with reference to Figs. 1 and Z, but having an abutment rnember 76 with an elongated, essentially flat base portion 7~ and upstanding portions ~0 with the integral corner portions joininy abutments 80 -to base 7~ being of significantly smaller radius than portions 54 of Fig. Z. In addi~-ion to a slightly concave upper surface of base portion 7~ ccntering of -the roller 44 may bè provided by biasing elemonts ~2 which are engageable with opposed lower surface portions ~4 of the roller 44 and also engageable wi-th inner surfaccs ~6 of abutment member 76 adjacen-t thc lower corners thereof. Biased retainers ~2 may be of solid soft elastomer construction, and preferably are formed to lcave a corncr void ~3 into which they may deform when contacted by roller 44.

Fiy. 5 illustrates yet ano-ther ernbodimet1t ot the invention in which the en-tire cavi-ty within the sidc and end walls of a side bearing carrier or housing is occupied by an enlarged upstanding elastomeric column 8~ and an asymmetrical abutmen-t member 90 having an upwardly concave recess in which there is received a roller 44. Accordingly abu-trnent mernber 90 includes a base portion 9Z and a single ups-tanding abutmen-t portion 94 whicl1 extends u~wardly adjacent the longitudinally inner side of elastomeric column 20~S412 ~ for longitudinal confinement of the same. The opposed end 96 of abutment member 90 interfaces with the end wall portions 24 of the bearing carrier thereby serving to position the abutment member 90 and provide a reaction interface to bear the longitudinal forces imposed upon abutment member 90 by confinement of elastomeric member in operation. End portion 96 together with upstanding abutment 94 and connecting base portion 92 define an upwardly opening recess 9~ within which roller 44 is free rolliny between longitudinal limits in much the same manner as above dcscribed with reference to other embodiments. In addition, it is noted that the base portion 92 is of increased thickness thus illustrating another means for elovatiny roller 44 ~o thereby permit the use of a smaller dialllctcr roller, with tt-e at-tcndant bcnefits as hereinabove described.

Additional embodiments and aspects of the invention are illustrated by Figs~ 6 to 15~ Fig~ 6 shows a side bearing similar to that shown in Fig. 5 and mounted on a truck bolster 101. Fig. 6 also includes a generally schematic representation of a car body wear plate 100 which is carried by a structural member 102 that is rigidly affixed with respect to a railway car body or platform (not shown). In Fig. 6, the side bearing roller 44 is shown residing at one extreme position with respect to spacer or abutment member 90 and spaced a near maximum longitudinal distance from a compliant bearing means shown as an elastomeric element 88.

23 205S 4l2 As noted hereinabove, one favorable aspect of the embodiment of Fig. 5 is that it allows use of a minimum-length wear plate. The wear plate which engages a side bearing must always be provided with a bearing surface area and dimensions to maintain proper bearing contact with the truck side bearing throughout the entire range of relative motion between the side bearing and the wear plate. In the case of prior side bearings with elastomeric bearing elements, the length of the car body wear plate had to be sufficient to maintain full coverage contact with the entire upper surface area of both of the elastomeric elements throughout the entire range of relative movement between the car body and the truck bolster.

Prior elastomeric side bearings, when they have included a separate rigid stop such as a rocker or a roller, typically have included a pair of longitudinally spaced elastomeric bearing elements with the rigid stop disposed therebetween. As it has been essential to maintain full coverage contact of the wear plate on the elastomeric bearing element engagement surfaces, the required length of the wear plate has been considerably greater than would be otherwise desirable.

The asymmetrical bearing structure of Figs. 5 and 6, having only a single elastomeric element and a solid stop such as the roller 44 disposed adjacent thereto, permits use of a much shorter wear plate. While the wear plate must still maintain full coverage of the upper bearing surface 104 of elastomeric element 88, there is no second elastomeric element spaced from the element 88 to impose a similar coverage or surface engagement requirement at a location spaced from 2o55~12 elastomeric element 88. Instead, the only other requirement for bearing surface engagemcnt is that the wear plate 100 be capable of engaging roller 44 in load bearing engagement throughout the available range of relative movement between the car body and the truck bolster 101, and throughout the available range of rolling movement for roller 44 with respect to abutment member 90 .

As shown in Fig. 6, even with roller 44 at the extreme position spaced as far as possible from elastomeric element bearing element 88, the high point of the roller top 106, which is the load bearing surface of roller 44, defines the furthest extent to which the adjacent end portion 108 of wear plate 100 must reach. So long as at least the end portion 108 of wear plate 100 overlies the bearing surface 106 of roller 44, load bearing engagement may be maintained therebetween.

Thus It will be appreciated that since the load bcaring surface portion of the roller does not extend throughout the longitudinal extent of the roller structure, but rather is centered with respect to it, the wear plate 100 need not extend to overlie the entire longitudinal extent of roller 44. That is, essentially half of roller 44 may lie outboard of the longitudinal reach of wear plate 100 since that portion of the roller 44 is never engaged by the wear plate 100. As a result, the required wear plate length is minimized.

Figs. 7 and 8 show another embodiment of the invention which may be regarded as somewhat similar in structure to the embodiments of Figs. 2 or 3, but with side bearing assembly 10 2055~12 turned by 900 with respect to its orientation in the Fig. 2 and 3 embodiments. The free rolling rigid element, however, retains a rolling orientation generally tangent to truck rotation. More specifically, the side bearing 110 of Figs. 7 and 3 is moun.ted on a truck bolster 101 and includes a carrier or cage such as a unitary cast cage member 112 with integral mounting lug portions 114 and a perimeter wall structure including end walls 116 and side walls 118. The cage 112 also includes integral interior partitions 120 spaced from each other and from side walls 11~ to define three cavities 122, 124, and 126 for receiving bearing elements therein.

The lntermediate cavity 124 is dimensioned in accordance with the above disclosure regarding other embodiments to receive roller 44 for free rolling of roller 44 therein between predetermined limits in the longitudinal direction, that is longitudinally with respect to a car body as above disclosed.
CavitieS 122 and 126 are spaced laterally to either side of cavity 124 and are dimensioned to receive and confine elastomeric bearing elements 123 for engagement with a wear plate 130 carried by a support structure 132 of a car body (not shown).

In this embodiment of the invention, the restraint characteristics provided by the elastomeric element and roller combination will be quite similar to those achieved with other embodiments of the side bearing above described; however, in the Fig. 7 and 3 embodiment, the elastomeric and rigid bearing elements are spaced apart in the lateral direction rather than 2055~12 in the longitudinal direction. Accordingly, this arrangement also serves to permit optimization of wear plate dimensions by reducing the longitudinal extent of the side bearing footprint, and thus the required wear plate length. As will be explained further hereinbelow, optimization of wear plate dimensions is generally desirable, but minimizing wear plate length in particular may be regarded as one of the more important optimization parameters.

Althougn the side bearing embodiments disclosed herein generally may be suitable for use in an orientation with the roller axis disposed radially with respect to the bolster center plate center, the embodiment of Figs. 7 and 8 in particular is well adapted for use in such a radial configuration. Radial positioning of the side bearing affords a further opportunity to minimize the length and width of the car body wear plate.

Fig. 9 shows a modification of the Fig. 7 and 8 embodimcnt as an asymmetrical bearing structure similar in some respects to the Fig. 5 and 6 embodiments but with the roller turned 900 from the roller orientation shown in Figs. 5 and 6, so that the roller rolls along side a single elastomeric bearing element rather than toward and away from it. More specifically, the Fig. 9 embodiment includes a cage or carrier 130 with mounting lugs 13Z for mounting thereof on a truck bolster. A perimeter wall structure 134 includes end wall portions 136 and side wall portions 138. An intermediate partition 140 divides the interior space within the bounds of the perimeter wall structure 134 into laterally adjacent cavities 142 and 144. A roller 44 is disposed for free rolling within limits in cavity 142 in the direction longitudinally of the side bearing and laterally adjacent to an elastomeric bearing element 1Z8 which is received and confined within cavity 144.

~ he Fig. 9 embodiment, like that of Figs. 7 and 8, permits another mode of wear plate size optimization. Specifically, the side bearing of Fig. 9 permits the longitudinal extent of the wear plate to be minimized, and in addition permits its lateral extent to be reduced further over that required by the Fig. 7 and 8 embodiment. Like the Fig. 7 and 8 embodiment, the side bearing of Fig. 9 can also be oriented in a radial position with respect to the truck center plate to minimize both the length and width of the car body wear plate. Also, it may be oriented on the truck bolster with the elastomeric column either inboard or outboard of the roller element.

~ igs. 10 and 11 disclose another asymmetrical side bearing having a single elastomeric element and a rigid stop such as a roller element disposed adjacent one another within a fabricated cage. More specifically, in Figs. 10 and 11 a cage member 146 may be formed by forming processes similar to those employed in the fabrication of conventional side bearing cages or carriers to include upstanding lateral side walls 148 and inturned longitudinal ends 150. In addition, intermediate the longitudinal ends of the carrier, a portion of each side wall 4 may be inturned at longitudinally adjacent locations 152 to divide the area within the confines of the carrier side and end walls into longitudinally adjacent cavities 154 and 156. An elastomeric bearing element 158 is received in cavity 156 and a rigid bearing element such as a roller 160 is received lonyltudinally adjacent thereto within cavity 152 for free rolllny within llmits longitudinally of the carrier 156 toward and away from elastomeric bearing element 158. , As in all of the above described embodin-ents, elastomeric element 15~ is provided with longitudinally spaced high buttresses or abutments, the buttresses in this case being in the form of conventional shim plates 16Z shown in side elevation in Fig. 10 and in plan view, partially broken away, in Fig. 11. These high-reaching buttress elements confine upper portions of the elastomeric element in the longitudinal direction to maintain more uniform engagement of the bearing element with a wear plate throughout relative motion therebetween under all levels of vertical loading. Of course, as in the above described embodiments, the uppermost extent of shim plates 162 is in any event lower than the uppermost extent of roller 160 so that the wear plate never engages the shim plates 162.
rhe Fig. 10 and 11 embodiment also discloses structure by means of which the desirable high-reaching buttressing for the elastomeric element may be achieved while maintaining use of a larger diameter roller than is used in other above described embodiments. Specifically, the Fig. 10 and 11 embodimcnts do not require any saddle or carrier member for the roller 160 such as disclosed in the Fig. 2 to 5 embodiments, for example.
Accordingly, the base surface 164 on which roller 160 rolls is at a lower elevation than the corresponding surface in the Fig.
2 to 5 embodiments. As a result, a larger diameter roller may be utilized.

205~412 Ot course it will be appreciated that use of a larger diameter roller in a given longitudinal space envelope reduces the available rolling range for the roller. Accordingly, to maintain a desired rolling range in a side bearing of the Fig.
10 and 11 embodiment, it may be necessary to extend cage 46, depending upon the diameter of the roller to be used, in order to provide the desired rolling range. ~owever, despite the longer cage length, the Fig. 10 embodiment will still accommodate a shorter car body wear platu than will prior sidc bearing designs, due to the benefit of the asymmetrical side bearing arrangement as discussed above.

I~ may be determined ln some circumstances that the benefit of a larger roller outweighs the desirability of a long rolling range within the bearing cage. Accordingly, the option provided by the instant invention of choosing a larger or a smaller roller is another example of the way in which the invention allows optimization of the side bearing and wear plate footprint.

ln ~ig. 12 a further embodiment of the invention is disclosed as a side bearing 164 comprised of an elongated cage or carrier 166 which may be fabricated by conventional means to include upstanding, longitudinally extending side walls 168 and inturned end portions 170 which are adapted to receivo shim plates 172. A saddle member 174, which may be similar to that described with reference to Fig. 5, is disposed within a cavity 176 defined within the confines of the side walls 168 and inturned ends 170 of carrier 166. Saddle 174 is located adjacent one longitudinal end of carrier 166 and includes a downwardly concave upper surface 178 on which a roller 180 is received for free rolling thereon within longitudinal limits.

2055~12 A longitudinal end 182 of saddle 174 extends upwardly to form a high-reaching buttress to confine between itself and the opposed end of carrier 166 a compliant bearing means which includes a pair of longitudinally adjacent elastomeric bearing elements 184 and a rigid, unitary bearing element 186 disposed atop the elastomeric bearing elements 184 and having an upper surface 188 which is adapted to engage a car body wear plate (not shown).

Tne elastomeric elements 184 are confined laterally by side walls 176 and longitudinally by shim plate 172 (also referred to as an end plate) and high-reaching buttress 182. In addition, the upper surfaces 190 of elastomeric bearing elements 184 which engage corresponding lower surface portions 192 of rigid bearing element 186 preferably are inclined with respect to the horizontal so as to converge downwardly. Accordingly, vertical loads applied through a car body wear plate to rigid bearing element 186 act through the interface between surfaces 190 and 192 to urge the elastomeric bearing elements apart in longitudinally opposed directions thereby maintaining uniform location of the bearing elements 184 within carrier 166 in all modes of bearing operation. In addition, the tendency of vertical loads to urge bearing elements 184 longitudinally apart automatically takes up any slack or free motion of the elastomeric portion of the Fig. 12 side bearing assembly such as might result from progressivo bearing wear or variation of component dimensions within manufacturing tolerances. The resulting confinement of the elastomeric elements 184 provides for a uniform and consistent restraint characteristic.

31 20S~ 412 Other features of the Fig. 12 embodiment include interlocking tongue portions 189 of rigid element 186 which project vertically downward into cooperating recesses formed in the upper surfaces 190 of the elastomeric elements 184. , Interengagement of the tongues and recesses serves not only to interlock the rigid element 186 to elastomeric elements 184, but additionally to carry laterally directed forces between the rigid element 186 and elastomeric elements 184 in part by lateral compression of the elastomeric elements 184 between the tongues 189 and the sidewalls of the bearing carrier.

Additionally, the angle of inclination for surfaces 190 may be steeper than that for surfaces 192 so that vertical compression of the elastomeric columns 184 is maintained as a uniform percentage of the overall elastomeric column height açross the entire elastomeric column horizontal cross section.

Fig. 13 shows a further example of a side bearing according to the instant invention wherein the bearing carrier or cage 192 is cast as a unitary member to include the mounting lugs or similar mounting structure, an elastomeric bearing element receiving cavity, a roller element receiving cavity, a free rolling range for the roller within the rollcr receiving cavity, high reaching longitudinal buttress portions to confine the elastomeric bearing element, and other structural elements corresponding to features of tho embodiments above describ~d, including an integral roller saddle portion with a high elevation floor or base to permit utilization of a smaller diameter roller.

Figs. 14 and 15 show fragmentary portions of a sidc bearing similar to that shown in Fig. 13 but including a rocker element instead of a roller as a rigid or solid stop. As has been noted hereinabovo, a self-centering roller, or moro generally a self-centering rigid stop, is desirable as one of the numerous disclosed ways in which the side bearing structurc may permit optimization of the side bearing footprint. A
self-centering structure such as a rocker permits accommodation of a larger radius rolling element in a given rolling pochct length.
~ s above noted, it lS desirable to havc available a frce rolling range, or more gcnerally a rangc of frce rnotion, for tt1C
solid stop bearing element in the longitudinal direction so tr~t when the wear plate is engagcd on the solid stop, rcl<ltivc movement of the wear plate on the side bcaring will not bc restricted by limits on the available range of roller or rockcr movement. If the roller or rocker is free to move throughout an extended range of relative motion, the restraint characteristic of the side bearing can be more easily maintained as a uniform characteristic since rolling engagement of the wear platc with the roller or rocker element will carry all tho overloads bcyond the load magnitude which produces the solid bearing condition while introducing no significant increment of restraint to relative pivoting movement betwoen the car body and the truck.
Accordingly, for all overload conditions, the elastomeric bearing element or elements will be under an essentially constant maximum vertical load and the elastomer shear rcstraint will be consistent and uniform.

20~5412 The required range of longitudinal movement for a solid bearing element can be minimized if the solid bearing element is positively self-centering. If the solid stop is positively self-centering, a shorter rolling cavity length will permit a sufficient range of movement in either longitudinal direction to accommodate the full range of longitudinal wear plate movement.
Gravitational centering as disclosed in other embodiments generally will permit more free oscillating motion of the rolling element when not under load. This results in less assurance that the rolling cavity limits will permit a sufficient range of roller motion under overload conditions, since the roller position when initially engaged by the wear plate will be less predictable.
Flgs. 14 and 15 disclose two structures for dealing with this problem. In Fig. 14, a rocker 194 is disposed within a cavity 196 of a bearing carrier 198. Opposed recesses 200 on the longitudinally opposed sides of rocker 194 receive ends of respective coil springs 202. The opposed ends of the respective springs 202 are received in recesses 204 which are formed in the respective longitudinally spaced upstanding end wall portions of cavity 196. Springs 202 preferably are identical and are maintained in a state of generally equal compression (which may include essentially zero compression) with the rocker centered, so that they exert essentially equal opposing longitudinal forces which serve to positively center rocher 194 longltudinally within cavity 196. The springs are preferably to be uncompressed when the rocker is centered, as any difference in the spring rate or length will result in the rocher being maintained, when not under load, in an off-center position.

Fig. 15 shows one spring bias ccntering arrangement which exerts essentially zero spring bias on the rocker at the centered position. , In Fig. 15 a solid stop structure is shown in which a rocker 206 is received within a cavity 208 formed in a carrier 210 having longitudinally opposed end walls 212 which diverge upwardly and are spaced apart sufficiently to provide a range of free motion for rocker 206 therebetween. Spring elements 214 are affixed adjacent the opposed longitudinal sides of rockcr 206. Springs 214 are generally of a V-shape having one lcg of the V affixed to a longitudinal side 213 of rocker 206 and the opposed leg of the V being free to engage a respective cavity surface 212.
On mo~ement ot the rocker 206 in roching motion longitudinally of cavity 208, the free leg of one or the other of springs 214 engages the respective cavity wall 212 and is compressed toward the other leg of the same spring to thereby bias rocker 206 back toward a centered position. Springs 214 thus function in a manner similar to springs 202 of Fig. 14 to maintain the rocker 206 in a centered position.
Positive self-centering is not the only benefit of the spring bias arrangements shown in Figs. 14 and 15. In these figures, the rocker elements 194 and 206 are shown in bearing cages with elevated rocker bases. That is, they are shown in configurations which are described above as being intended for smaller diameter rollers or rochers. However, when used in an embodiment without an elevated rocher floor, the positive self-centcring structure can be much more important.

2055~12 Without the elevated rocker floor, a larger diameter rocker may be used, and indeed in many circumstances a larger diameter rocker may be desirable, for example a 4" diameter rocker. As has been noted, however, a larger diameter solid bearing element requiring a given minimum longitudinal range of free movement will require a corresponding longitudinal clearance within the bearing cage. A larger diameter roller thus requires a larger longitudinal clearance. The use of a rocker, which is essentially a roller with its upper and lower radiused portions intact and its sides truncated, reduces the longitudinal clearance requirement and thus helps to optimize side bearing overall size by minimizing the overall side bearing length requirement even though the radiused surfaces of the rocker present a relatively large diameter structure for rolling engagement with the bearing in the solid condition.

The positive centering structures disclosed in Figs. 14 and 1~ serve to permit the further reduction of the longitudinal clearance required by the rocker since, as noted hereinabove, a self-centering structure helps to ensure that the rocher element will be centered when first engaged by the wear plate as the bearing goes solid. Accordingly, use of a rocker with positive centering within a space offering a range of free longitudinal movement permits overall bearing length to be minimized in general without resorting to a smaller diameter solid stop bearing element for rolling engagement with the wear plate in the solid condition. Of course, the Fig. 14 and 15 embodiments relate to the use of a rocker in lieu of a roller in a much more 36 2055~12 general sense. If a range of longitudinal freedom is provided for a rocker, the rocker design will be limited by the requirement that the rocker be stabile , i.e. self-righting when displaced from its upright position. The disclosed springs may permit use of a rocker design, fQr example a rocker of minimal longitudinal extent, which is not inherently self-righting.

Described hereinabove are.a number of structural advances in side bearings which permit the overall dimensions of the side bearing, most notably its longitudinal extent (in the direction of the car body length), to be minimized. One motive for achieving such minimal dimensions is seen in the design and geometry of such railway rolling stock as long intermodal cars wherein a shorter overall side bearing structure and shorter bearing footprint are highly desirable due to the more restrictive bearing space limitations. For example, the increased distance between the trucks of long intermodal cars results in a larger maximum angle between the connected cars in turns. This can result in the adjacent side bearing wear plates of the pivoted car bodies on the inside of the turn coming into closer than usual proximity to each other.

All ot the a~ove described asymmetrical bearing structures wherein a rigid or solid stop is located adjacent to a single elastomèric bearing element or a compliant bearing assembly can be of significant benefit for reasons beyond the desirability of optimizing the bearing footprint or the wear plate surface dimensions. For example, such an asymmetrical bearing structure allows freedom in the selection of the maximum load bearing location with respect to the bolster and the car body.

As has been noted, all bearing loads beyond those required to bring the bearing to a solid state or condition are carried by the bearing rocher or roller. Accordingly, by merely turning the asymmetrical side bearing assembly end-for-end, the location of the elastomeric bearing element with respect to the location of the bearing overloads may be changed. In some embodiments of the invention, this may be accomplished by simply removing the solid stop, saddle member, and elastomeric column from the bearing cage and reversing their positions therein. In other embodiments, the entire side bearing is turned end-for-end. The invention thus provides a side bearing which is adapted for use in a variety of configurations to achieve distinctly different objectives.
More speciflcally, in some rolling stock such as modern high load capacity cars, the invention permits side bearings to be placed closer to the truck bolster center line. Side bearings located as close as possible to the bolster center line are less able to exert a turning moment on the bolster tending to rotate it about its longitudinal axis. For those instances in which it is deemed most desirable to avoid such turning moments, an asymmetrical side bearing structure of the present invention may be so mounted that the solid stop is located longitudinally closer to the bolster center line and the elastomeric element is located longitudinally further therefrom.
This orientation will produce the smallest possible turning moments upon the bolster as all overloads tending to overturrl the bolster will be acting on the shortest possible moment arm.

38 205~412 There may be other circumstances in which it is more desirable to locate the solid stop as close as possible to the car body support structure. For example, in such rolling stoch as long intermodal cars the side bearing wear plates of the car bodies may often be supported on outrigger structures which extend laterally and/or longitudinally from the car body frame to a position overlying the side bearing carried by the truck bolster. The required strength of such wear plate support structureS is determined in part by the distanco of the maximum loads borne by the wear plate from the car body frame.

An incremental strength requirement due to a larger distance between the car body frame and the furthest point of maximum wear plate load application will necessitate a more massive wear plate support structure, including enlargcd beam sections and gussets over those which would be required if the maximum wear plate loads were borne closer to the car body framo.

Since the maximum loads borne by the wear plate occur where the wear plate engages the solid stop of the side bearing, an orientation with the side bearing solid stop located closer to the car body frame and further from the bolster center line may be desirable in such instances. Of course, in goneral it is always desirable to minimize the structural mass of any portion of a railway car, including the side bearing wear plate support structure, in order to minimize the car tare weight.

2055~12 The above described side bearing structural features can be utilized in various combinations to selectively position or locate the application of overload forces, provide for free rolling wear plate to bearing engagement throughout the r~nge of overload forces borne by the bearing after the wear plate goes solid upon it, maintain uniform elastomeric bearing restraint (especially shear restraint) throughout the range of overload forces borne on the side bearing and reduce side bearing footprint size.

Accoraing co the description hereinabove there is provided by the instant invention a novel and improved side bearing assembly for use especially in conjunction with moderrl rail car body and truck configurations. Although the invention has been described with reference to certain prescntly preferred embodiments, it will be appreciated that I have envisioned various alternative and modified embodiments within the scope of the invention as described.
Amony such modifications, I have contemplated a side bearing generally as above described but with more ttlarl two elas-tomeric columns spaced longitudinally of a bearing carricr and with rollers frce rolling within limits in abutments members disposed between each pair of adjacent elastomeric columns. Additionally, a bearing of this invention may be constructed to the proportions of an unusually elongated housing member to provide a sinylc beariny assembly which provides support for both of tlle mutually adjacent ends of a pair of car platforms which are supported on a common truch bolster. The elastomeric columns may be configured in a variety of geometric shapes and from a variety of elastomeric materials according to the penformance requirements of the par-ticular car body and truck assembly. Certainly such ~lterna-tive embodiments would also occur -to others versed in the art, once apprised of my invention. Accordingly, it is intended that the inverl-tion be construed broadly and limited only by the scope of ttle claims appended hereto.

Claims (10)

1. In a railway vehicle side bearing having a rigid elongated housing which is adapted to be carried by a railway truck to support a railway car body with the housing having laterally spaced, upwardly projecting side walls and longitudinally spaced, upwardly projecting end walls with respective uppermost edges, such side and end walls enclosing an upwardly open elongated cavity, a bearing assembly adapted to be received within such elongated cavity for engagement with a wear plate carried by such railway car body comprising:
compliant bearing means adapted to be disposed within such elongated cavity adjacent at least one of such walls and having an upper end surface means disposed vertically above such uppermost edges;
said compliant bearing means including at least one upstanding, resiliently deformable elastomeric bearing element having a vertically extending surface portion;
a rigid, elongated spacer means adapted to be disposed within such elongated cavity adjacent said vertically extending surface portion;
said spacer means including an upwardly facing surface means extending thereon, and an upstanding abutment means which is cooperable with at least some of such walls and engagable with claim 1 cont'd said vertically extending surface portion to at least partially confine said elastomeric element within such cavity;
rigid bearing means supported on said upwardly facing surface means and being moveable thereon in opposed directions within predetermined limits;
said compliant bearing means being disposed transversely adjacent the path of movement of said rigid bearing means in said opposed directions;
said rigid bearing means being of an overall vertical height that, when supported upon said upwardly facing surface means with said spacer means disposed within such cavity, said rigid bearing means has an uppermost extent located above such uppermost edges of such side and end walls;
said elastomeric element being vertically deformable in compression and having an overall vertical height when disposed within such elongated cavity that said upper end surface means of said compliant bearing means is disposed vertically above said uppermost extent of said rigid bearing means to maintain a vertical spacing between said rigid bearing means and such wear plate throughout a range of vertically downwardly directed loadings applied to said elastomeric element by engagement of said compliant bearing means with such wear plate and to permit such wear plate to engage said rigid bearing means when said vertically downwardly directed loading on said elastomeric element equals a given load; and said abutment means being engagable with said vertically extending surface portion at an elevation above such uppermost edges of such side walls and end walls to confine at least a portion of said elastomeric element above such side walls and end walls under such vertically downwardly directed loadings.

2. The bearing assembly as set forth in claim 1, wherein said rigid bearing means is a roller means which is adapted to be free rolling on said surface means within said limits.

3. The bearing assembly as set forth in claim 1 wherein said compliant bearing means includes a pair of said elastomeric elements adapted to be disposed at spaced locations within such elongated cavity and said spacer means includes a respective pair of spaced upstanding abutment portions with said upwardly facing surface means extending intermediate said upstanding abutment portions.

4. The bearing assembly as set forth in claim 3 wherein said limits include opposed confronting surface portions of said upstanding abutment portions.

5. A railway vehicle side bearing adapted to be carried by a railway truck for engagement with a car body wear plate in load bearing engagement comprising:
a rigid housing;

claim 5 cont'd said housing including an elongated base portion and a pair of opposed, spaced apart upstanding wall portions extending vertically upward of said base portion and having respective uppermost edges;
an upwardly open cavity defined within said housing intermediate said pair of wall portions, respectively;
upwardly facing surface means extending within said cavity;
rigid bearing means supported on said upwardly facing surface means for movement thereon within predetermined limits in a given direction;
compliant bearing means disposed within said cavity at a location spaced from said upwardly facing surface means in a direction transverse to said given direction;
said compliant bearing means having a respective upper end surface means disposed vertically above said uppermost edges and including at least one upstanding, resiliently deformable elastomeric bearing element;
said rigid bearing means being of an overall vertical height, when supported on said upwardly facing surface means, that said rigid bearing means has an uppermost extent located above said uppermost edges of said pair of wall portions;
upstanding abutment means disposed within said cavity intermediate said compliant bearing means and said rigid bearing means and extending upwardly adjacent said elastomeric bearing element to at least partially confine said compliant bearing means, said abutment means extending upwardly to an elevation intermediate the elevation of said uppermost extent of said rigid bearing means and said uppermost edges of said wall portions; and said elastomeric bearing element being vertically deformable in compression and having an overall vertical height when supported within said cavity that said upper end surface means of said compliant bearing means is disposed at an elevation vertically above said uppermost extent of said rigid bearing means to maintain a vertical spacing between said rigid bearing means and such car body wear plate throughout a range of vertically downwardly directed loadings applied to said elastomeric element by engagement of said compliant bearing means with such car body wear plate, and to permit such car body wear plate to engage said rigid bearing means when said vertically downwardly directed loadings on said elastomeric element equal a given load.

6. The side bearing as set forth in claim 5 wherein said compliant bearing means includes a pair of compliant bearings supported within said cavity at locations displaced from said surface means in transversely opposed directions, respectively, transverse to said given direction.

7. A railway vehicle side bearing adapted to be carried by a railway truck for relative shearing movement with respect to claim 7 cont'd a car body wear plate while in load bearing engagement with such wear plate, said side bearing comprising:
a rigid housing;
said housing including an elongated base portion and upstanding wall portions extending vertically upwardly of said base portion and having respective uppermost edges;
an upwardly open cavity defined within the confines of said wall portions;
upwardly facing surface means extending within said cavity;
a rigid bearing means disposed on said upwardly facing surface means for movement thereon within predetermined limits in a given direction generally in alignment with the direction of such relative shearing movement between said side bearing and such wear plate;
a single compliant bearing means disposed within said cavity at a location spaced from said surface means in a direction transverse to said given direction;
said compliant bearing means having an upper end surface means disposed vertically above said uppermost edges for load bearing engagement with such wear plate;
said compliant bearing means including at least one upstanding, resiliently deformable elastomeric bearing element;

said rigid bearing means being of an overall vertical height, when disposed on said upwardly facing surface means, that said rigid bearing means has an uppermost extent located above said uppermost edges of said wall portions for load being engagement with such wear plate;
upstanding abutment means disposed within said cavity intermediate said compliant bearing means and said rigid bearing means, said abutment means extending upwardly adjacent said elastomeric bearing element to an elevation above the elevation of said uppermost edges of said wall portions; and said elastomeric bearing element being vertically deformable in compression and having an overall vertical height when disposed within said cavity that said upper end surface means of said compliant bearing means is disposed vertically above said uppermost extent of said rigid bearing means to maintain a vertical spacing between said rigid bearing means and such car body wear plate throughout a range of vertically downwardly directed loadings applied to said elastomeric element by engagement of said compliant bearing means with such car body wear plate, and to permit such car body wear plate to engage said rigid bearing means when said vertically downwardly directed loadings on said elastomeric element equal a given load.

8. The bearing assembly as set forth in claim additionally including biasing means cooperable with said rigid bearing means to urge said rigid bearing means toward an intermediate position intermediate said predetermined limits of movement of said rigid bearing means in said opposed transverse directions.

9. The bearing assembly as set forth in claim 5 additionally including biasing means cooperable with said rigid bearing means to urge said rigid bearing means toward an intermediate position intermediate said predetermined limits of movement of said rigid bearing means in said opposed transverse directions.

10. In a railway truck side bearing including a housing with perimeteral walls having uppermost edges to define an upwardly open cavity which receives an upstanding compliant bearing means and a rigid bearing means adjacent said compliant bearing means wherein said rigid bearing means is engagable with a car body wear plate and has a predetermined range of available lateral movement with respect to said compliant bearing means and an uppermost extent which is located at an elevation above said uppermost edges and below the uppermost extent of said compliant bearing means when said rigid bearing means is not engaging said car body wear plate, and wherein said side bearing assembly requires a predetermined minimum magnitude of shear restraint to be provided by relative shearing movement of the car body wear plate with respect to said compliant bearing means under vertically directed loading on said compliant bearing means by engagement thereof with said car body wear plate, a method of claim 10 cont'd maximizing said predetermined range of available lateral movement comprising the steps of:
buttressing a vertically extending surface of said compliant bearing means including an upper vertical extent thereof which extends intermediate said uppermost extent of said rigid bearing means and said uppermost edges to confine said compliant bearing means for limiting movement thereof toward said rigid bearing means throughout at least said upper vertical extent of said vertical surface to thereby increase the magnitude of such shear restraint available for a given said compliant bearing means;
providing said compliant bearing means with a reduced longitudinal section thickness sufficient to provide, consistent with said buttressing step, said minimum magnitude of shear restraint; and supporting said rigid bearing element for spring-biased self-centering thereof within said predetermined range of available movement.