CA2055582C - 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

A railway freight car commonly includes a car body supported on the eenter plates of a pair of longitudinally spaced trucks. The coned wheels of -the truchs en(gage the respective rails of a railway track and the -trucks travel a generally sinuous path along tangent track as they continually seeh a centered position under the steerir-g influence of the wheel conici-ty. 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 lino of the truch bolster center pla-te. A railway truch also will yaw or rota-te quasi-statically with respect to the car body in negotiating curved track.

As a result of such lateral truch oscillation and cyclic yawing, unstable -truck hun-ting responses can develop if -the frequency of the cyclic motion approaches resonance.
Referenee is made hereby -to prior U.S. patent 3,957,313 for further de-tailed explanation of railway vehicle truch hun-til1g phenomena, and such explanation is hereby incorporated herein by reference.

~ailway car body roek and roll is another problem in railway ear stability that is related to the trueh hunting phenomenon. As the trueks of a railway ear negotiate their sinuous path of travel along the railway track, the car body will move laterally in concert with the cyclic lateral rnovemcnt of the -truck center plates. The loaded or heavy car readily tolerates this lateral oscillation; howevcr, -the empty or light car body may be driven to rock latcrally from side to side. As with hnown -truck hunting phenomena, this la-teral rock and roll empty car body motion can also be driver- by resonant coupling to des-tructive extremes.

~ailway truch side bearings have long been utilized to provide support for a car body with respect to a truck laterally outward o~ the 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, bu-t 1S addltlonally by the negotiation of trach curves and the superelevated trach erlcountered in curves.

Olaer Conventional side bearings have includcd roller bearin~s carried for rollin~ movement longitudinally wlthir 2~ an elon(Jatcd cage or carrier mounted on a railway truch bolster. The roller extends above tlle uppermost ex-terlt of tlle open top of the carrier for rolling engagement with a wear plate carried by the car body. Such side bearings are able to support a car body with respect to.a truch bolster laterally ou-tward of the truch center plate while at the same time permitting the bolster, and theref-ore the truch, the freedom to rotate with respect to the car body as is necessary to accommodate the normal truch movement along 3 2 0 5 S ~ 8 2 both tanc~or-t and curvod track as above described.

rhe art has also contemplated railway truck side bearings which serve not only to support a car body with respec-t to a truch bolster during relative rotational movelllent tllerebetw¢er), but in addi-tion to dissipate energy through frictional engagement between the car body wear plate and a bearing element whereby the requisite rotational f-reedom of the truck with respect -to the car bocly is maintained whlle a degree of restraint is also provided as a means to control and limit destruc-tive huntin~ responses.
Still furtl1er, the prior art has contemplated -the use of elas-tomeric elements to cushion the vertical loading of a car body on a truch bolster exerted througt1 -the side L)earing s-tructure. Still other prior side bearir1gs have corltelnpla-ted roller bearing structures with self-centeriny rollers.

Among the prior side bearlngs known in tl1e art as 2~ above characterized are those disclosed in U.S. patents 1,33l,926, 2,301,37Z, 2,754,763, 3,255,712, 3,Z95,463, 3,313,Z4~, 3,493,Z21, 3,513,943, 3,556,503, 3,623,464, 3,670,661, 3,719,154, 3,796,167 and 4,359,039.

In some prior side bearings, the desired function was purely 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 ~- 4 205~582 wi.th respect -to the truck bolster, as well as rota-tional restrain-t throuyh the frictional dissipation of energy. Tho above-cited patent 4,B59,039 is one example of such an energy dissipating side bearing.

Other more recent prior art side bearings such as that disclosed in U.S. paten-t 4,090,750 have contempla-ted the use of bearing elemen-ts ~ormed of elastomeric columns ancJ
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 bolster, as well as a friction interface between the elastomeric columns and the car body wear plate to provide frictional energy dissipation upon relative rotation of the car body with respect to the bolster.

Still o-ther recent prior ar-t side bearlngs such as those disclosed in U.S. patent 4,0B0,016 and 3,957,31B, combine elas-tomeric columns to provide support and tr-lc~lonaL energy dissipation as above characterized, and roller elements to limi-t the magnitude of vertical ~e~lec-tion 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 mo-tion of the wear plate downward toward the bolster, a range of relative rotational freedom for the car body with respec-t to the bolster withou-t significantly increasing frictional restraint with greater side bearing _ 5 2 0 5 5 5 8 2 loadir)g beyond that affordecd by the elastomeric columns alone.

Another truch bearing structure, not so recent, is disclosed in U.S. patent 3~ Z as a ball bearing elcment disposed in a downwardly concave cup which is in turn resiliently supported by an elastomeric ring elemen-t.

The presen-t invention contemplates a novel and lmproved rallway truck side beariny structure especially well sui-ted for use in railway truck and car body comt~lnatlons unknown when many of the above ci-ted prior bearings were dovelopod. 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 clevelopment did not contomplate the operclting conditions and problems posed by modern car configurations.

More speciFically, certain newer types of railway cars u-tilize articulated couplings between pairs of adjacont car platforms that share a common intermediate truck having a f].a-t center plate bearing. These and other car Con~lgUrationS often may have longer spacing between adjacent trucks; that is, the car platform leogths, and therefore the inter-truck spacing, may be greater than in ~ 6 20S5582 convel1tional cars. S-taching of containerized loads anct similar transport modes for these and other cars, often characterized as intermodal cars, has resulted in loadcd cars with extremely high cen-ters of gravity, for example as much as 110 inches abovc the track.

In these and other car configurations, -the role of tllc side bearing in supporting tt1e car body with respect to thc bols-ter has been al-tered dramatically. For example, in very high center of gravity loaded cars, most particularly the doub:Lc s-tached container configurations, the loaded car body center of gravity is located well above the articulated connec-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 platform and containerized lading may be insufficient to keep the car body end tha-t is suppor-ted in sptlerical bearing segmcnts from leaning continuously to one lateral side or -the o-thcr for relatively extendcd periods of car travel. If tlle lading is off-center, or in such operational circurnstances as tt-e traverse of track curves, extended periods of large magnitude side bearing loading may be virtually unavoidable.
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 accommodate controlled rotational freedom between the truck an~ thc car body through an angle equivalent to the ma~imum relative rota-tion -therebetween and this in turn requires maximum longitudinal rolling freedom for the roller bearing elemen-t. The maximum relative rotation between a car body and a truch in normal operation may be as grea-t as the relative rotation experienced from a short radius left hand turnout to a similarly short radiused right hand turnout althouyh 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 curvc.

~hc exten~e~ plattorm lenytlls of some modern cars ~lso can require a greater range of relative rotational freedom between -the -truck and the car platform because a longor pla-tform requires a grca-ter angle of rolative rotatior between the platform and -the respective truchs -to ncgotiate curvcd trach of any given radius. Still further with grcatcr car load capacities and higher centers of gr~vity 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 wi-th respect to the center plate bearing. This too incrcases the maynitude of roller bcaring movcrnent nceded to z5 accommodate relative truch-to-car body rotation. An additional 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 utilized in a given 8 205~582 application. It is preferred under most circumstances to koep tl)e "footprint" of a side bearing (i.e. the size of the car body wear plate required to cooperate with the side beariny) as small as possible, even though modern car desiyns often call for increased rather than reducecl bearing load capaci-ty and ranye of movement.

BRIEF SUMMA~Y OF THE INVENTION

Ihe present invention contemplates an improved side bearing structure which is especially well suited for use with intermodal cars and similar modern car configurations haviny larye load capacities, high cen-ters of gravity, longer truck spacing, and other design features to which some prior side bearings might be less well suited in the tash of optimizing -the dynamic performance of the car. Tl1e invention con-templa-tes generally a railway -truch side bearing assembly which is preferably adapted -to be confined withir1 a generally conven-tional, standard railway truck side bearing housing or carrier and including at least one upstanding elastomeric bearing element and a longitudinally adjacent spacer member disposed within the carrier. The spacer member includes at least one upstanding abutment whicll longi-tudinally confines a corresponding elastomeric Z5 colurlln, and a yenerally upwardly facing elongated surfaco to receive a rigid bearing element such as a roller tl1erein.
Tl1e roller is provided a range of free rolling movement longi-tudinally of the spacer member between s-tops or limits delined by lon(3i-tudinally spaced portions of -the spacer rnember.

rhe range of free movement for the roller can be made sufficient to accommodate the greater range of relative rotary movement between a bolster and a car platform required in modern car configurations as discussed hereinabove without sacrifice of frictional energy dissipation capability provided by the elastomeric columns.
This is so in part because -the upstanding abutments of the spaccr member can extend upwardly above the uppermost extent of the bearing carrier or housing and adjacent an uppcr portion oF a corrcsponding elastomeric column to longitudinally bu-ttrcss and confine the elastomeric elemcnt sufficicntly that it does not bend longitudinally over -the top of the confining abutment.

Accordingly, surface contact betwecn the upwardly facing bearing surface of the clastomeric column and thc car 2~ body wear pla-te is maintained more uniformly and the full benefit 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 thichness of elastomer, especially in the longitudinal direction, may z~ be employed to attain the same lovels of performance as re(Jards shear restraint as in prior elastomeric sidc bearings requiring larger section elastomeric columns.
Thus, without sacrificing the desirable con-trol capabilities lO 2055582 -of a larger section elastorncric column, an increascd rangc of longitudinal roller motion is made available in a side bearing llousing oF given dimensions.

It is therefore one objcc-t of the prescnt ir-vcntior- to provide a novel and improved railway truck side bearing;

Anothcr object of the invention is to provide an improved railway truch side bearing comprised of at lcast one ups-tanding elastomeric column bearing and a rigid roller or si.milar element which providcs a rigid limit to vcrtical compression of the elastomeric column, and structure and method of partially confining the clas-tomeric column and maximizing the free rolling range for the bearing roller element.

Still anotller ob~ect of the invention is to providc, for use in a railway truck side bearing, an abutment or spacer element whicll serves to partially confine an upper .extcnt of an elastomeric bearing element and in addition to elevate the rolling surface of a rigid roller beariny elcment above the base of the bearing housing such tllat a smallcr diameter roller than commonly employed may bc utilized.

These and other objects and further advantages of the invention will be more fully appreciated upon considcration of thc following detailed description and the accompanying drawings in which: 2 0 5 5 S 8 2 Fig. 1 is an end elevation showing a side bearing according to one presently preferred embodiment of the instant invention and cooperating portions of a railway truck and car body;

Fig. 2 is a sectioned side elevation of a sidc bearing takcn on line 2-2 of Fig. 1;

Fig. 3 is a sec-tiorled side elevation showirlg an alternative ernbodiment of the instant invcntion;

Fiy. ~ is a sectioned side elevation showing anothcr alterna-tive embodimen-t of the instan-t invention;

Fig. 5 is a sectioned side eleva-tion showing still another 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 illustratcd 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 brohen away;

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

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

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

~horo lS gcne-ally indicated ~t 10 in Fiys. 1 ~nd 2 a side bearing assembly which is carried atop a bolster 12 of a railway truck and is secured thereto as by threaded fastencrs 14 for cooperative interaction with the wcar plate _ 13 2055582 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/

2055~82 _ -14-adjacerlt, inturned end flange por-tions of- side walls 22.
For tl)is and other bearing carrier end wall configurations, shilll plates 26 may be assembled wi-th end wall portions 24 such tllat upper portions 28 thereof overlie the uppermost extont of end wall por-tions 24, and a lower extent 30 of each shim plate 26 extends adjacent an inner surface of tlle end wall portions 24, respectively, and downwardly into tlle confines of carrier 20.

The carrier 20 further includes a longitudinally and laterally extending base portion 32 which, in conjunction with side walls 22 and end walls 24, fbrms an upwardly openiny cavi-ty 34 to receive and confine an assembly of side bearing elemen-ts.
It will be seen that side walls 22 and ond w<311s 24 project upwardly -to an uppermost extent WlliCIl iS at a uniform elevation. Additionally, the upper extent Z~ of eacll sllim plate 26 projec-ts to an elevation above -tlle uppermost extent 36 of the side and end walls 22, 24 for a purpose to be described hereinbelow.

Within the confines of space 34 is received an assembly of bearing elements comprised preferably o-- 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 tlle respective shim plate 26, an elongated spacer or -abutmcnt mernber 42 received within space 34 lonyitudinally intermediate elastomeric columns 40, and a rigid bearing melllbCr such as a roller 44 is received wi-thin space 34 intermediate side walls 22 and within the confinement of an upwardly 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 longi-tudinally apart to reside longitudinally inward~.y adjacen. the respective clastomeric columns 40, and inte(Jral curved or radiused portions 54 which extend intermediate base portion 43 and the respective abutment portiorls 52.

It ~ill be noted that abu-tment portions 52 extend upwardly to an uppermost ex-tent 56 which, lihe the uppermost por-tions 23 of shirn plates 26, project above the upper ex-tent 36 of the side walls 22 and end walls 24 to an elevation preferably just slightly below the highest elevation of roller 44. Accordingly, upstanding abutments are provided at an elevation above the hi~hest lateral abutment provided by carrier 20 such tha-t 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 devclopment of non-uniform loading of the elastomeric _ columns 4~ in compression. Moro particularly, rolative rotation be-tween car body 18 and bolster 12 results at all load lcvels in shear deformation of elastomeric columns 40 in the longitudinal direc-tion and ultimate friction breah and longitudinal sliding of wear plate 16 on the uppermost surfaccs 41 of elas-tomeric col'umns 40. Both the control provided by horizontal shear deformation of the elas-tomeric columns prior to frictional sliding between surfaces 41 and wear plate 16, and the energy dissipation achieved by ~rictional sliding movement be-tween the surfaces 41 and plate 16 are optimized in part by abutments 52 which constrain the elas-tomeric columns 40 to remain essentially upright under all operating conditions and load levels.

-l5 In prior side bearinys wherein a relatively elonyated extcnt of an elastomeric column projec-ted above the hiyhes-t lonyitudinal abutments and was -therefore relatively unconfirled in at least one longitudinal direction, relativo 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 elastomeric columrls a tendency to bend lonyitudinally. This is espocially true of the trailiny or rearward elastomeric ~ coll~mr1, reckoned Witt1 rcspect to the direction of longitudinal movement of the car body wear plate 16 with respect to the side bearing assembly. Such elastomer column bendiny produces non-uniform loadiny across the surface 41 of the elastomeric element thereby significantly deyrading the shear restraint available at the wear plate--to-el~stomer _ 17 2055582 interface. By providing abutments pro]ecting upwardly, pre~-ferably above the bearing carrier side and end walls, and especially for the lor)git-udinally opposed sides of the elastomeric elomcnt, 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 without such longitudinal abutments.

Accordinyly, the desired characteristics of shear restraint in the elastomer-to-wear plate in-terface can be achieved with elastomcric columns of smaller cross section than required in prior side bearings. Therefore, within thc confines of a given bearing carrier 20 more longitudinal spacc is available between elastomoric elcments 40 by use of srllaller section elastomeric elements to provido a greatcr longi-tudinal rolling range for roller 44. The side bearing thus can accommodate increased angular rotation between -truch 12 and car body 1~.

The lnwardly facing surfaces 60 of member 4~ provide rigid stops or limlts for roller movement such tha-t roller 44 will not la-terally deform elastomeric elements 40 as it 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 longitudinally with respect to housing 20 so that when roller 44 enyages ono of surfaces 60, the member 4~ can roll or tilt slightly in the samc longitudinal direc-tion 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 engagemel1t of the roller on the surface 60.

It wlll be noted tha-t the uppermost extent ot rollcr 44 projects above the uppermost exten-t of the sidc walls 22 and end walls Z4, and additionally above the uppermost extcnt of the shim pla-te upper ends 2~. The roller 44 also projccts above the uppermost projection 56 of tl1e abutmont portions 52, although preferably only very slightly above.
Accordingly, when the loading on elastomeric columrls 40 deforms them in vertical compression to the solid condition whereat plate 16 engages roller 44, plate 16 remains at all timcs clear of contact with side walls 22, end walls 24, shim plates 26 and abutmen-t projections 56, and only a very minimal vertical ex-ten-t of the elas-tomeric columns projccts abovc the uppermost extent 56 of abutments 52.

Inasmuch as one object of this invention is -to provide, within the confines of a given bearing carrier, the neccssary longitudinal free rolling range for a rollor bcaring olement to accommodatc the greater rclativo rotational movement between a truck and a car platform as must be accommodated in some modern cars, it will be noted that an additional advantage provided by abutment member 4 is that it elevates the rolling surface on whicl) rollor 44 is supported above the uppermost surface 50 of base 32.
Accordirlgly the uppermos-t exten-t of roller 44 projects further upward by an equal increment thereby permitting the use of a smaller diame-ter roller than could be otherwise employed where the load limits to be encountered by the roller bearing permit. A smaller diameter roller occupies less of -the longitudinal rolling range available between the limits defined by the abutment member 4~ thereby providing further increased lonyitudinal free rolling range ror 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 housiny 20.
Other embodiments of the lnvention are shown in Figs.
3 through 5. In Fig. 3 the bearing assembly shown is esserltially identical in most salient respects to that described hereinabove with reference to Figs. 1 and Z;
2~ however the abutment member 62 is configured to include a base portion 64 which is of a concave conf-iguration to provide a generally concave upper surface 66 on which roller 44 is supported. The roller 44 thus tends to be gravitationally self-centering when in a free rolling state Z5 ~i.e. not engaged by the car body wear plate) to ensure that sufficient 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 sorne mo~lcrll cars with extremely high centers of gravity when loadcd will tend to lean over on one or tlle other of sidc bearirlys on a given truch for rela-tively long periods of travcl. For any embodiment of this invention, the available free rolling space in either lonyitudinal direction for roller 44, when centercd, should be sufficient to accommodate the maximum relative truck to car body rotation wllich can occur under such circumstances.

A~dltionally, abutment membér 62 is free to roch longitudirlally within housing 6~ if the concave upper surtace 7~ on which member 62 rests is of a larger radius than the ma-ting convex surface 75 of member 62. As member 62 rocks, the upstanding abutment at -the leading end tllereof (witl7 respect to the direction of its longitudinal rocking) compresses the corresponding elastomeric element 40. The roching action of member 62 presents -to the roller a progressively lower angle of inclination on surface 66 as the roller 44 moves up the incline of surface 66 when displaced from its centered position. Without the rocking capability for member 62, as the roller moves to one side or the other from i-ts centered position it rolls up the centering incline, and the side bearing thus is lifting the entire weight supported thereon vertically upward. Tllis increase in the vertical loading on the side bearing roller, increases the directly proportional horizontal restraint between the roller and body plate 16, which is undesirable;
however, such lif-ting reduces elastomer compression l1ousing 6~ beneath the abutment member 62.

Fig. 4 discloses another alternativo embodilner)t of the inveotion similar in many salient respects to that described wi-th reference to Figs. 1 and 2, but having an abutment member 76 with an elongated, essentially flat base portion 7~ and upstanding portions ~0 with the integral corner portions joininy abutments ~0 to base 7~ being of significantly smaller radius than portions 54 of Fig. 2. In addition to a slightly concave upp~r surface of base portion 7~, centeriny of the roller 44 may be provided by biasing elemcnts ~Z which are engageable with opposed lower surface portions ~4 oF -the roller 44 and also engageable with inner surfaccs ~6 of abutment member 76 adjacent the lower corners thereof. Biased re-tainers ~2 may be of solid, so~t elastomer cons-truction, and preferably are formed to leave a corncr void ~3 into which they may deform when contacted by roller 44.

Fig. 5 illustrates yet ano-ther embodimel1t ot the inverltion in WhiCtl the entire cavi-ty wi-tl1in -the side and end walls o~ a side bearing carrier or housing is occupied by an enlarged upstanding elastomeric column ~ and an asymmetrical abutment member 90 having an upwardly concave recess in which there is received a roller 44. Accordingly, abu-tment member 90 includes a base portion 92 and a single upstanding abuttnent portion 94 which extends upwardly adjacent the lonyitudinally inner side of elastomeric column 22 205~582 for longi-tudinal confinement of the sarne. The opposed en(l 96 of abutment member 90 interfaces with tl1c 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 8 in operation. End portion 96 together with upstanding abutment 94 and connecting base portion 92 define an upwardly opening recess 98 within which roller 44 is free rolliny between longitudinal limits in much the same manner as above described with reference to other embodiments. In addition, it is no-ted that the base portion 92 is of increased thickness thus illustrating another means for elevatiny roller 44 to -thereby permit the use of a smaller dialllctcr roller, with the at-tendant 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. ~ 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.

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 asymmetrlcal 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 ..
elastomeric element 88. Instead, the only other requirement for bearing surface engagement is that the wear plate 100 bo 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 bearing 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 rcsult, 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 _ 25 20ss582 turned by 900 with respect to its orientation in the Fig. 2 and 3 embodiments. The free rolling rigid element, however, rctains 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 113. The cage 112 also includes integral interior partitions 120 spaced from each other and from side walls 113 to define three cavities 122l 124, and 126 for receiving bearing elements therein.

rhe 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 12~ 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 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 parame-ters.

Although the side bearing em~odiments 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 embodiment as an asymmetrical bearing structure similar in some respects to the Fig. 5 and 6 embodiments but with the roller turned 90 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 132 for mounting thereof on a truck bolster. A perimetcr 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 14Z and 144. A roller 44 _ 27 2055582 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 128 which is recoived and confined within cavity 144.

~ he fig. 9 embodiment, lihe 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.

figs. 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 48 may be inturned at longitudinally adjacent locations 15Z 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 28 205558~

rigid bearing element such as a roller 160 is received longltudinally 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 embodiments, 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 162 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 thc uppermos-t cxtent of roller 160 so that the wear plate never engagcs thc 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 embodiments 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.

Ot course it will be appreciated that use of a larger diameter roller in a given longitudinal spacs envelope reduces the available rolling range for the roller. Accordingly, to maintain a desired rolling range in a side bearing of thc 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 thc longer cage length, the Fig. 10 embodiment will still accommodate a shorter car body wear plate than will prior side bearing designs, due to the benefit of the asymmetrical side bearing arrangement as discussed above.
It may be determined in 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 lnvention 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 receive 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.

A longitudinal end 182 of saddle 174 extends upwardly to form a high-reaching buttress to confine between itself and tho 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 18Z. 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.

20~82 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 1~4. , 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 across 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 1g2 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 roller receiving cavity, high reaching longitudinal buttress portions to confine the elastomeric bearing element, and other structural elements corresponding to features of the embodiments above described, including an integral roller saddle portion with a high elevation floor or base to permit utilization of a smaller diameter roller.

_ 32 205S~82 Figs. 14 and 15 show fragmentary portions of a side 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 bcen noted hereinabove, a self-centering roller, or more generally a self-centering rigid stop, is desirable as one of the numerous disclosed ways in which the side bearing structure 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 pochet length.
~ s above noted, it lS desirable to have available a free rolling range, or more generally a range of free motion, for the solid stop bearing element in the longitudinal direction so that when the wear plate is engaged on the solid stop, relative movement of the wear plate on the side bearing will not be restricted by limits on the available range of roller or rocker 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 plate with the roller or rocher element will carry all the overloads beyond the load magnitude which produces the solid bearing condition while introducing no significant increment of restraint to relative pivoting movement between 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 restraint will be consistent and uniform.

20S~582 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.
~ l95. 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 rocker 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 rocker being maintained, when not under load, in an off-center position.

Fig. 1~ 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 rocher 206 is received within a cavity Z08 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 rocher lO 206. Springs 214 are generally of a V-shape having one leg 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 Z06 in rocking motion longitudinally of cavity 208, the free leg of one or the other of springs 214 engages the respective cavity wall 21Z 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 20 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 rockers. However, when used in an embodiment without an elevated rocker floor, the positive self-centering structure can be much more important.

20~5~82 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 rocker element will be centered when first engaged by the wear plate as the bearing yoes 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 __ 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, for 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 thc side bearing, most notably its longitudinal extent (in the direction of the car body length), to be minimized. Onc 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 truchs of long intermodal cars results in a larger maximum angle between ~he 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 of the above described asymmetrical bearing structures wherein a rigid or solid stop is located adjacent to a single elastomeric 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.

` 37 As has been noted, all bearing loads beyond those reguired 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 trom 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 ohjectives.
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 overturn the bolster will be acting on the shortest possible moment arm.

` 38 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 stock 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 distance 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 enlarged beam sections and gussets over those which would be required if the maximum wear plate loads were borne closer to the car body frame.

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 general 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.

~ 39 20~5582 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 range 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.

Accor~ing co the description hereinabove there is provided by the instant invention a novel and improved side bearirlg assembly for use especially in conjunction with modern rail car body and truck configurations. Although tlle invcrltion has been described with reference -to certain prescntly preferred ombodiments, it will be appreciatcd that I llave 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 than two elas-t~meric columns spaced longltudinally 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 sinyle beariny assembly which provides support for both of the mutually adjacent ends of a pair of car platforms which are supported on a common truck bolster. The elastomeric columns may be configured in a variety of yeometric shapes ancl frorn a variety of elastomeric materials according -to the performance requiremerlts of the particular car bo~y arld truch asscmbly. Certainly such alternative cmbodiments woukl also occur to others versed in the art, once apprised of my invention. Accordingly, it is intended that the invcrltion be construed broadly and limited only by the scope of the claims appended hereto.

Claims (2)

1. In a railway vehicle side bearing wherein a plurality of load bearing elements are confined for load bearing engagement with a railway car and a truck to provide at least partial support of such railway car with respect to such truck, a unitary housing for confining such plurality of load bearing elements comprising:
a lower base portion having an elongated upwardly facing surface;
a pair of laterally spaced side walls which extend longitudinally of said surface and project upwardly of said surface;
a pair of end closure means extending transversely intermediate said side walls adjacent longitudinally spaced portions thereof, respectively;
said side walls and end closure means enclosing an upwardly open cavity extending above said surface;
at least one of said side walls including an inwardly formed integral means disposed intermediate said longitudinally spaced portions and projecting transversely of said cavity from said at least one of said side walls to a location transversely intermediate said pair of side walls to divide said cavity into at least a pair of longitudinally adjacent cavity portions each adapted to receive at least one of such load bearing elements;
said integral means being cooperable with said side walls to at least partially confine such load bearing elements in said cavity portions, respectively; and said inwardly formed integral means including a pair of integrally formed inturned portion of at least one of said side walls disposed longitudinally adjacent each other, and a breach means formed in said at least one of said side walls longitudinally intermediate said inturned portions.

2. The housing as set forth in claim 1 wherein both of said side wall means include said first and second inturned portions, respectively.