GB2055722A - Squaring device for a railroad car truck - Google Patents

Abstract

A railroad car truck 10 comprises a pair of spaced elongate side frames 12, having pedestal jaws 14 at ends thereof, wheelsets 46 having axle ends 44 journaled in bearings 48 carried within the pedestal jaws 14, and elastomeric devices 70 each interposed between a bearing 48 and its respective pedestal jaw 14. Each elastomeric device includes an elastomeric pad 78, 80 sandwiched between metal plates, 72, 74, 76 and has a low stiffness rate in shear and a high stiffness rate in compression and tension, and is arranged so that lateral movement of a wheelset is in a direction of shear of the device, and longitudinal movement is in a direction of compression or tension, thereby to maintain the wheelsets 46 and side frames 12 in squared relationship whilst allowing relative lateral movement. <IMAGE>

Description

SPECIFICATION Squaring device for railroad car truck The present invention relates to a squaring device for a railroad car truck, and to a railroad car truck incorporating such' a device.

More particularly the invention relates to a truck wherein each wheelset may move laterally to continuously centre itself with respect to the track over which the truck is travelling, concurrently, the wheelsets are maintained in a squared relationship with other truck components, in particular side frames of the truck.

The railroad car wheel in common use today has a conical-like tread profile which produces a centring effect with respect to the track over which the car truck is travelling.

During travel this centring is continual in that the distance between the tracks is not constant nor is the track absolutely straight. To accomplish this centring, the wheelset must move laterally with respect to a longitudinal axis of the truck. These lateral movements were readily accommodated within the now obsolete sleeve bearing type journal boxes.

With the adoption of the roller bearing, such lateral movements of the wheelset were inhibited.

Therefore, other means have been provided to allow this desirable lateral movement. Such means are disclosed for example in U.S. Patent Nos. 2,762,317, 2,737,907, 3,744,474 and 3,352,255. An even further improvement is disclosed in U.S. Patent application Serial No. 849,027 (U.S. Patent No ) According to an aspect of the present invention there is provided a railroad car truck comprising a pair of spaced elongate side frames, each said side frame having a pedestal jaw formed at each each end thereof, a pair of spaced wheelsets having axle ends journaled in bearings carried within respective pedestal jaws, and elastomeric devices for locating the bearings within the pedestal jaws whereby movement of said wheelsets longitudinal of said side frames is inhibited, said wheelsets and said side frames are maintained in squared relationship whilst allowing movement of said wheelsets laterally relative to said side frames and lateral centring of said wheelsets is facilitated.

More particularly each elastomeric device is carrid by an adaptor affixed to a respective bearing.

The elastomeric device preferably comprises a plurality of metal plates separated by elastomeric pads. The pads have a low stiffness rate in shear and a high stiffness rate in tension and compression. The device allows relative laterial movements between each wheelset and the side frames in that the elastomeric pads are placed in shear during such movements. While allowing the lateral movements, the device inhibits both relative vertical and longitudinal movements between the wheelsets and the side frames in that the elastomeric pads are placed in compression and tension during such movements.

The railroad car truck of the present inven tion has several advantages over known trucks.

A first advantage is that the wheelsets and the side frames are maintained in a substan tially squared relationship. The relationship is maintained in spite of the wheelsets inherent tendency to hunt or yaw, i.e. uncontrolled oscillating about a vertical axis of the wheel set. Additionally, when the wheelsets and side frames are maintained in this squared relation ship, the side frames and bolster are pre vented from lozenging. Lozenging tends to promote wheelset hunting. A second impor tant advantage is that the wheelsets of this truck may move laterally to accommodate for variation in the distance between the tracks over which the truck is travelling. Because modern railroad car wheels are formed with a conical-like tread profile, the wheelset is self centring.Where lateral movement between the wheelset and side frame is inhibited, the entire truck and railroad car body must be centred. Attempting to centre sch a substan tially greater mass increases track and wheel wear.

Lastly, a railroad car truck having the above-noted desirable characteristics may be produced without a substantial change to its heretofore known and standardized structure and therefore without considerable additional expense.

The present invention will be further de scribed by way of example with reference to the accompanying drawings, in which: Figure 1 is a partial elevational view in section through a railroad car truck according to the present invention.

Figure 2 is a perspective view of an elas tomeric device according to the present inven tion incorporated as part of the truck of Fig.

1.

Figure 3 is a cross-sectional view of the truck of Fig. 1 generally seen along the line 3-3 of Fig. 1.

Figure 4 is a cross-sectional view of the truck of Fig. 1 generally seen along the line 4-4 of Fig. 1.

Referring to the Figures, truck 10 typically includes a pair of spaced elongate side frames with a portion of one such side frame 1 2 shown. The truck 10 further includes a trans versely positioned bolster (not shown) which may support in part a body (not shown) of the railroad car. Formed at ends of each side frame 1 2 is a pedestal jaw with the one jaw shown designated 1 4 and being typical of the remaining.

The pedestal jaw 14 includes a lower por tion 1 6 defined by spaced front and rear end walls 18, 20. It should be understood that the truck 10 is nondirectional and that the terms "front" and "rear" are used merely for distinguishing purposes. Each end wall 18, 20 has an upper radiused portion 22 which projects inwardly to terminate at front and rear inner spaced end walls 24, 26. The end walls 24, 26 define in part an opening 28 to an upper portion 30 of the pedestal jaw 1 4. The upper portion 30 has an inverted V-shaped roof 32 defined by a front and a rear inclined portion 34, 36 which converge upwerdly and join to form a radiused roof apex 38. A lower end of each roof portion 34, 36 terminates at a concave-shaped end wall 40, 42, a lower end of which joins front and rear inner end walls 24, 26 respectively.

Separating the axle ends 44 of the wheelset 46 from the side frame 1 2 is a bearing 48 allowing the wheelset 46 to freely rotate as the car truck 10 moves forward or backward during operation. On an upper portion 50 of the bearing 48 is an adaptor 52 having a wedge-shaped configuration as shown.

The adaptor 52 is positioned within the upper portion 30 of the pedestal jaw 14 and is defined by a lower radiused surface 54 which interfaces with the upper portion 50 of the bearing 48. The adaptor 52 further includes an upper front and rear flat inclined engaging surface 56, 58 which converge upwardly and join at a radiused apex 60. On each side of the front and rear flat engaging surfaces 56, 58 is a pair of inner and outer spaced grooves 62, 64 positioned parallel to and proximately equidistant on each side of a longitudinal axis of the adaptor 52.

Between the adaptor 52 and the side frame pedestal jaw roof 32 is an inverted V-shaped or chevron-shaped elastomeric device 70 which is shown in detail in Fig. 2. The device 70 includes an upper, middle and lower metal plate 72, 74 and 76 separated by elastomeric pads 78, 80. The plates 72-76 and pads 78, 80 may be joined into a rigid structure by suitable bonding technique. The pads 78, 80 have a low stiffness value in shear but a high stiffness value in compression and tension.

The upper plate 72 and the lower plate 76 are divided into a front and rear inclined contact portion 82, 84 and 86, 88 respectively formed at an angle to complementarily engage with the pedestal jaw roof portion 34, 36 and the upper engaging surface 56, 58 of the adaptor 52.

The inclined portions 86, 88 of the lower plate 76 join at a radiused corner 90 having a dimension slightly greater than that of the apex 60 of the adaptor 52 so as to provide a space 92 therebetween when the side frame 1 2 is fully loaded. Similarly the front and the rear inclined portions 82, 84 of the upper plate 72 join at a radiused corner 94 having a dimension slightly less than that of the apex 38 of the pedestal jaw roof 32 to also provide a space 96.

Along an inner and outer edge 98, 100 of the upper plate 72 are two pairs of spaced, upwardly projecting tabs 102. The tabs 102 fit snugly against inner and outer sidewalls 104, 106 of the side frame 14. In a similar manner, along inner and outer edges 108, 110 of the lower plate 76 are two pairs of spaced tabs 11 2 which project downwardly and fit snugly within the adaptor grooves 62, 64.

During operation of the truck there are continuous relative vertical, longitudinal and lateral movements between the wheelsets 46 and the side frames 1 2. As seen in Fig. 2, the arrow V-V' represents the vertical direction, and the arrow Lo-Lo', represents the longitudinal direction and the arrow La-La', the lateral direction. Because the wheels of the wheelsets 46 have a conical-like tread profile and because the distance between the tracks over which the wheelset 46 travels is not constant nor straight, each wheelset 46 attempts to move laterally to centre itself with respect to the track. Centring each wheelset 46 with respect to the track is most desirable in that it reduces wheel and track wear and minimizes frictional resistance to travel.

As the wheelset 46 attemps to move laterally, i.e. in the La-La' direction, it places the elastomeric pads 78, 80 in shear since the upper plate 72 and lower plate 76 are secured to the side frame 12 and the adapter 52 and the pads 78, 80 are secured to the plates 72-76. Because the pads 78, 80 have a low stiffness value in shear, lateral movements between the upper and lower plates 72, 76 may readily occur allowing relative lateral movements between the wheelset 46 and the side frame 1 2. Thus, each wheelset 46 may more readily move across the track to take up an optimum wear postion.

While it is desirable to allow lateral movement between the wheelset 46 and the side frame 12, it is equally desirable to maintain the wheelset 46 and the side frame 12 in a squared relationship. Maintaining this squared relationship prevents the side frame 14 and bolster from lozenging, i.e. the bolster is outof-square with respect to a body of the railroad car and the side frame remain parallel by becoming longitudinally offset from each other. When lozenging occurs, the critical speed at which the wheelsets will hunt is reduced. Because the wheelset 46 may also hunt or yaw, i.e. an inherent dynamic tendency of a wheelset to oscillate about its vertical axis above the critical speed, the wheelset 46 must be restrained against such if such occurs.

During such hunting, the wheelset 46 attemps to rotate and thus the axle ends 44 moves in the Lo-Lo' direction.

When the axle end 44 moves in the Lo' direction, for example, the upper rear surface 58 of the adaptor 52 is forced against the rear portion 88 of the lower plate 76 of the elastomeric device 70. This force is transferred to the rear inclined portion 36 of the pedestal jaw roof 32. No significant longitudinal movement of the wheelset 46 with respect to the side frame 1 2 occurs because of the high compression stiffness value of the pads 78,80.

Thus, the wheelset 46 is inhibited from hunting while at the same time the side frames 1 2 are inhibited from lozenging to provide a more stable railroad car truck having improved wheel wear characteristics.

While various modifications may be suggested by those versed in the art, it should be understood that the present invention embodies all such modifications as reasonably and properly come within the scope of the accom

Claims (9)

panying claims. CLAIMS

1. A railroad' car truck comprising a pair of spaced elongate side frames, each said side frame having a pedestal jaw formed at each end thereof, a pair of spaced wheelsets having axle ends journaled in bearings carried within respective pedestal jaws, and elastomeric devices for locating the bearings within the pedestal jaws whereby movement of said wheelsets longitudinally of said side frames is inhibited, said wheelsets and said side frames are maintained in squared relationship whilst allowing movement of said wheelsets laterally relative to said side frames and lateral centring of said wheelsets is facilitated.

2. A railroad car truck as claimed in claim 1, wherein each elastomeric device is carried by an adaptor affixed to a respective bearing.

3. A railroad car truck as claimed in claim 1 or 2, wherein each elastomeric device comprises a pad of elastomeric material having a low stiffness rate in shear and a high stiffness rate in tension and compression, such that in use said relative lateral movement is in a direction of sheer of said pad and said longitudinal movement results in compression or tension of said pad.

4. A railroad car truck as claimed in claim 3, wherein each elastomeric device is chevron-shaped and comprises one or more pads held between upper and lower plates.

5. A railroad car truck having a pair of spaced side frames carrying transversely therebetween a bolster for supporting thereabove a body of a railroad car, and a front and a rear wheelset each having axle ends journaled in bearings operatively positioned within pedestal jaws formed at ends of said side frames, each said pedestal jaw including a roof having an inverted V-like configuration defined by a front and a rear inclined portion converging upwardly and forming a radiused apex, each said bearing carrying an adaptor having a lower portion, each said adaptor having an upper front and rear inclined engaging surface converging upwardly and forming a radiused apex, and an elastomeric device having chevron-like configuration complementarily formed with respect to a said adapter and a said pedestal jaw roof, each of said devices having a lower plate engagable with adapter upper engaging surfaces and an upper plate engagable with pedestal jaws inclined portions respectively, said plates separated by an elastomeric pad thereby to allow selective relative movements between said wheelsets and said side frames.

6. A railroad car truck having a bolster transversely carried between spaced side frames and a pair of wheelsets operatively connected to said side frames by having axle ends journaled in bearings respectively located within a pedestal jaw formed at ends of each said side frame, wherein each said pedestal jaw has a lower portion defined by spaced end walls having an upper radiused portion to receive therein said bearing, said radiused portions terminating at an inner end wall to define an opening therebetween to an upper pedestal jaw portion, said upper portion including a chevron-shaped roof defined by a central radiused apex joined by downward inclined portions having lower ends joined to said inner end walls, and there are provided.

adapter means each defined by a concave lower portion formed to complementarily fit over a said bearing, each said adapter means having an upper front and rear inclined engaging surface joining a radiused apex, said adapter upper surfaces projecting within a said upper portion of a said pedestal jaw and including a pair of spaced grooves formed along inner and outer sides of said upper surfaces, and an elastomeric device interfaced one each between said adapter and pedestal jaw roof, each said device having an upper, middle and lower plate, each pair of adjacent plates separated by an elastomeric pad having a low shear stiffness rate and a high compression stiffness rate, said plates formed on an angle complementary to said upper adapter portion and said pedestal jaw roof so as to provide areas of substantial contact therebetween, said lower plate having pairs of downwardly projecting spaced tabs which fit within said adapter grooves to secure said lower plate to said adapter, and said upper plate having pairs of upwardly projecting spaced tabs which engage an inner and outer side of each said side frame and secure said upper plate to said side frame.

whereby, in use, said low shear stiffness rate of said elastomeric pads allows relative lateral movement between said wheelsets and said side frames to accommodate centring forces created between said wheelsets and tracks over which said truck travels, and said high compression stiffness rate of said elastomeric pads inhibits relative longitudinal movements between said wheelsets and said side frames to restrain oscillating forces created between said wheelsets and said track and maintain said wheelsets and said side frames in a squared relationship.

7. An elastomeric device as defined in any of claims 1 to 6.

8. An elastomeric device substantially as hereinbefore described with reference to the accompanying drawings.

9. A railroad car truck substantially as hereinbefore described with reference to the accompanying drawings.