Articulated Railway Truck Swinging Bolster

Abstract

Railway trucks which include front and rear wheel and axle assemblies, frame sections supported from said wheel and axle assemblies, spherical bearing assemblies connecting said frame sections for pivotal movement about a diagonal axis, spring seats supported from the side frames by articulated swing hangers, laterally deflectable spring assemblies on the spring seats, and a bolster supported by said spring assemblies.

Description

This invention relates to novel, improved railway trucks.

At the present time large sums of money are being spent for rolling stock intended for high speed passenger service. One of the requirements of such stock is that it provide a comfortable ride under a variety of service conditions.

To produce a comfortable ride, it is necessary to absorb shocks generated by lateral offsets in tracks such as occur at frogs, switches, and crossovers, for example. Also it is necessary to cushion and limit lateral movement of cars as they negotiate curves at high speeds or are otherwise subjected to high lateral forces or loads. Aside from producing a comfortable ride, it is also necessary to limit lateral movement of the bolsters and therefore the car body relative to the track in such stock because of the limited clearances at station platforms, for example.

One important object of the invention resides in the provision of novel railway trucks capable of providing a ride of superior quality under a wide variety of track, load, and other service conditions.

Another important object of the invention resides in the provision of railway trucks with novel, improved bolster suspension systems for cushioning laterally acting loads of both low and high magnitudes and for limiting lateral movement of a carbody relative to a railroad track.

The novel railway trucks of the present invention, by which the foregoing and other objects are achieved, include a pair of frame sections supported from front and rear wheel and axle assemblies. Each of the frame sections includes a longitudinal side frame and a transom extending transversely from it, the two transoms being spaced longitudinally of the truck. The two frame sections are connected by spherical bearings in the manner described in U.S. Pat. No. 3,313,245 issued Apr. 11, 1967, to maintain the side frames in rectangular and vertical tram.

A carbody supporting bolster is supported from the truck side frames by novel bolster support assemblies which include laterally deflectable coil spring assemblies interposed between the bolster and spring seats located below the bolster at opposite ends thereof. The spring seats are supported from the side frames by articulated swing hangers.

When there is a small displacement of the carbody relative to the truck frame as caused by an offset in a track, for example, this novel combination of laterally deflectable coil springs and articulated swing hangers provides relatively low magnitude restraining and restoring forces which absorb the shock and prevent it from being transmitted to the carbody. In the case of larger lateral forces such as occur in high speed curve negotiation, for example, these suspension components combine to produce much larger restraining and restoring forces and thereby prevent unwanted motions of the carbody.

Bolster suspension systems employing articulated swing hangers have heretofore been proposed (see U.S. Pat. No. 1,867,654 issued July 19, 1932, to H. T. Casey for SWING HANGER FOR RAILWAY TRUCKS). The Casey suspension system, however, differed considerably from that employed in the novel trucks disclosed herein. In the latter, the articulated swing hangers alter the action of laterally deflectable, bolster supporting coil springs so that the springs have a low restraining force for absorbing shocks and the like, but a greater restraining effect when the laterally acting force is of larger magnitude. The Casey arrangement does not employ laterally deflectable bolster springs, but depends on the exertion of a lifting effect on the truck bolster to produce a restoring force. This comparatively primitive arrangement would not be satisfactory for modern day high speed service.

The use of coil springs to provide lateral restoring and restraining forces has also heretofore been proposed. Typical of the patents disclosing such systems are U.S. Pat. Nos. 2,723,628 issued Nov. 15, 1955, to W. T. Rossell for BOLSTER ASSEMBLY and 2,737,126 issued Mar. 6, 1956, to the same inventor for DIFFERENTIALLY ACTING BOLSTER CONTROL. In these and other heretofore proposed bolster suspension systems employing laterally deflectable springs, however, the bolster is supported directly from the truck side frames by the springs rather than through the intermediary of articulated swing hangers.

In short, there has heretofore been no recognition of the advantages that may be realized by employing laterally deflectable springs in combination with articulated swing hangers in bolster suspension systems.

Primary objects of the present invention have been described above. Other important objects and advantages and further novel features of the present invention will become apparent from the appended claims and as the ensuing detailed description and discussion proceeds in conjunction with the accompanying drawing, in which:

FIG. 1 is a side view of a railway truck constructed in accord with the principles of the present invention;

FIG. 2 is a plan view of the truck of FIG. 1;

FIG. 3 is a section through the truck of FIG. 1, taken substantially along line 3--3 of FIG. 2; and

FIG. 4 is a section through the truck of FIG. 1, taken substantially along line 4--4 of FIG. 2.

Referring now to the drawing, FIGS. 1 and 2 depict a railway truck 20 constructed in accord with the principles of the present invention. Truck 20 may be of the same basic construction as the novel truck described in the above-cited U.S. Pat. No. 3,313,245. The truck has a rectangular frame 26 consisting of two generally L-shaped, rigid subassemblies or frame sections 28 and 30. These subassemblies are formed by longitudinally extending side frames 32 and 34 secured to or integral with laterally extending, longitudinally spaced transoms 36 and 38.

Frame sections 28 and 30 are interconnected at diagonally opposed points by spherical bearing assemblies 40 and 42 to permit relative pivoting between them about a diagonal axis 44 through the centers of the spherical bearings and the center of the truck.

Truck frame 26 is supported on axles 45 and 46 by roller bearing assemblies 48 which are resiliently mounted in frame 26. Axles 45 and 46 each have railway wheels 50 secured thereto.

Because of the manner in which the frame subassemblies 28 and 30 are interconnected by bearing assemblies 40 and 42, there is only one type of motion therebetween. This is a pure pivotal movement of one sub-assembly with respect to the other about axis 44. Accordingly, as truck 20 rolls onto an uneven stretch of track on which one of the wheels 50 furthest from axis 44 is at a low point in the track, the associated frame subassembly tends to pivot downwardly about axis 44 to re-establish even wheel loading. Conversely, when a wheel furthest from the pivoting axis is on a high point on a rail, its frame sub-assembly pivots upwardly about axis 44 to re-establish even wheel loading.

Thus, the construction of frame 26 provides independent side frame action. However, as the spherical bearings do not permit longitudinal play between the frame sub-assemblies, the side frames of the truck 20 are rigidly maintained in rectangular tram. Further, as the spherical bearings do not permit vertical play between the ends of the transoms and the opposite side frames, the side frames are maintained in vertical tram. Finally, as the spherical bearings permit no lateral play between the transoms and the opposite side frames, they effectively rigidly transmit lateral forces from one side to the other..sup.1

Supported from truck frame 26 are motors 52 driveconnected to axles 45 and 46 by gear boxes 54 as well as brake assemblies 56. These components are not part of the present invention and will accordingly not be described further herein.

Also supported from truck frame 26 by novel suspension assemblies 58 is a transversely extending bolster 60. Bolster 60, which is of generally conventional construction, has an integral fitting 62 which co-operates with a depending member (not shown) and a safety hook 63 fixed to the underside of a carbody 64 to pivotally support one end of the carbody from truck 20. Liners 65 and 66 in the recess 67 in fitting 62 minimize resistance to relative pivotal movement between the truck and the carbody.

Referring now to FIGS. 1-4, each of the bolster supporting assemblies 58 includes a spring support or seat 68 supported from a truck side frame 32 or 34 by a pair of articulated swing hangers 70 and 72 together with a spring assembly 74 disposed on the seat and abutting a spring cap 76 at the end of bolster 60.

As best shown in FIG. 4, each of the spring assemblies 74 includes an inner coil spring 78, an outer coil spring 80, and an air bellows 82 surrounded by a reinforcing ring 83. The two coil springs 78 and 80 are positioned by annular flanges

Bellows 83 are fixed to the associated spring seats and spring caps by annular retainers 88 and 90, which are bolted to these components. As shown in FIG. 4, these retainers are configured to interlock with flanges 92 and 94 at the lower and upper ends of the bellows to form gas tight seals between spring support 68 and the lower end of the bellows and between the upper end of the bellows and spring cap 76. In operation, the interiors of the bellows 82 are pressurized so that carbody 64 is supported by a combination of air and spring suspension.

To limit the lateral movement of spring supports 68 and bolster spring assemblies 74 relative to bolster 60, lateral control pins 96 are employed. These pins are fitted into apertured bosses 98 on the lower side of the bolster and extend downwardly through an aperture 100 in a vertical arm 102 at the inner end of said spring support. Washerlike members 104 and 106 are welded to support arms 102 to reinforce the areas around the apertures.

Referring now specifically to FIGS. 1 and 3, each of the articulated swing hangers 70 and 72 includes an upper arm of pendulum 108 and two pairs of lower arms or shackles 110 and 112. As best shown in FIG. 1, pendulums 108 are supported from side frames 32 and 34 for lateral pivotal movement about an axis parallel to the longitudinal axis of truck 20 by pivot members 114. These pivot members extend through the upper ends of the pendulums and through brackets 116 and 118 fixed to the associated side frame on opposite sides of each pendulum.

Turning now to FIG. 3, frame sections 28 and 30 are of hollow, cast construction; and each pendulum 108 extends downwardly through an aperture 120 in the upper or top wall 122 of the associated frame section and an aperture 124 through an integral, vertically oriented, flangelike portion 126 on the lower side of the frame section.

Stops 128 are fixed in each aperture 124 on opposite sides of the associated pendulum 108 by cap screws 130 and are separated from the cap screws as by shims 132. Stops 128 limit the lateral, swinging movement of pendulums 108 relative to the side frames with which they are associated.

As will be apparent from FIGS. 1 and 3, there is one pair of shackles 110 at the outer side of each pendulum and one pair 112 at the inner side. At their upper ends, shackles 110 are fixed to the pendulum on opposite sides thereof as by a pivot member 134. The upper end of shackles 112 are similarly fixed to the pendulum at the inner side thereof as by a pivot member 136.

The shackles 110 of swing hangers 70 and 72 are pivotally fixed to integral upstanding flanges 138 and 140 at the front and rear of the associated spring support 68 by pivot members 142 and 144. The shackles 112 of the two hangers are similarly fixed to these flanges inwardly of shackles 110.

As mentioned briefly above, it is the function of the novel suspension assemblies 58 just described to isolate carbody 64 from shocks due to lateral offsets in a track and the like by providing relatively low restraining and restoring forces and to produce such forces of higher magnitudes during high speed curve negotiation, for example, to prevent unwanted motions of the carbody. A relative lateral force between bolster 60 (and accordingly carbody 64) and truck frame 26 will cause swing hangers 70 and 72 to pivot about pins 114. This displaces the lower ends of the coil springs 78 and 80 in bolster suspension assemblies 74 relative to the upper ends, the springs absorbing the lateral force as this displacement occurs. When the force is dissipated, the springs restore to their original configurations. This returns the bolster and carbody to their normal positions with respect to the truck frame.

If the lateral force has a relatively low magnitude, the swing hangers 70 and 72 pivot about members 114 as solid links; i.e., the shackles 110 and 112 do not pivot relative to the pendulum 108. Accordingly, the displacements of springs 78 and 80 are relatively small; and the resistance of relative lateral movement between the bolster and truck frame as well as the forces exerted by these springs in restoring the bolster and carbody to their centered position are low. This type of operation is particularly effective for absorbing shocks and the like, yet permits the relatively free lateral movement between the carbody and truck frame on straight track which is needed for a high quality ride.

If the displacement effecting forces are larger, the action of the suspension assemblies will initially be the same. However, as the swing hangers continue to pivot, pendulums 108 engage stops 128, which prevent further lateral movement of the pendulums. Thereafter, shackles 110 and 112 pivot laterally about pivot members 134 and 136. Because of the shorter moment arm, the displacement of the lower spring ends relative to the upper spring ends increases as does the restraining effect and the restoring force exerted by the springs. Accordingly, the springs are in such circumstances capable of smoothly absorbing these larger laterally acting forces.

As the upper and lower ends of springs 78 and 80 are displaced relative to each other, the spring configuration is such that, taking a lateral plane through each spring and considering one edge of the two dimensional figure thus produced, this edge is a compound curve. One portion of the curve is concave and the other convex.

The level at which the transition between the concave and convex curves occurs is conventionally known as the point or level or plane of inflection. For suspension systems 58 to operate satisfactorily, the level at which shackles 110 and 112 are pivotally connected to spring supports 68 (i.e., the level of pivot members 142 and 144) must be approximately the same as the level or plane of inflection of the springs in bolster supporting spring assemblies 74.

Provision is preferably made in the novel railway trucks of the present invention for positively limiting lateral movement of the supported carbody relative to the truck frames and for cushioning abnormally large shocks; i.e., shocks having a magnitude greater than those which assemblies 58 are designed to accommodate. In the exemplary embodiment of the invention illustrated in the drawing, these objectives are accomplished by resilient stops 146 fixed to integral, upstanding brackets 148 at the ends of bolster 60. Under the influence of abnormally large lateral forces, one of the stops 146 will engage the inner wall 150 of a side frame 32 or 34 to cushion the shock and to limit the movement of bolster 60 and carbody 64 laterally with respect to truck frame 26.

To further increase ride quality, the novel trucks of the present invention are also preferably equiped with radius rods 152, lateral shock absorbers 154, and vertical shock absorbers 156. These components, which are connected between truck frame 26 and bolster 60, are of conventional construction and function in the usual manner. For this reason and because they are not part of the present invention, it is not believed necessary to described them in detail herein.

While the principles of the present invention have been described with reference to motorized trucks, it will be obvious to those familiar with the arts to which this invention relates that they are equally applicable to unmotorized trucks. It will also be apparent to such persons that the principles of the invention can be embodied in trucks differing widely in appearance from the truck illustrated in the drawing. Such applications of the principles described herein are fully intended to be covered in the appended claims to the extent that they are not expressly excluded therefrom.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

What is claimed and desired to be secured by Letters Patent is:

1. A railway truck comprising front and rear wheel and axle assemblies; side frames supported from said wheel and axle assemblies; spring support means at each side of said truck; articulated swing hangers; a bolster extending laterally across said truck; vertically extending, laterally deflectable spring means disposed on said spring support means and supporting said bolster therefrom; and first and second means pivotally connecting said swing hangers to said side frames and to said spring support means respectively for movement about axes extending in the same direction as the side frames, the second of said means connecting said swing hangers to said spring support means at generally the level at which the spring means inflect as said bolster moves laterally relative to said side frames and laterally displaces the upper ends of said springs relative to the lower ends thereof.

2. A railway truck comprising front and rear wheel and axle assemblies; a frame including laterally spaced apart side frames, said frame being supported from said wheel and axle assemblies; a spring support at each side of said truck; fore and aft swing hangers supporting each of said spring supports from the side frame on the same side of the truck, each said swing hanger comprising an upper link supported from the side frame for pivotal movement about an axis extending longitudinally of the truck, a lower link fixed to said upper link for pivotal movement about a second axis extending longitudinally of the truck, and means fixing the lower link to the spring support for pivotal movement about a third axis extending longitudinally of the truck; laterally deflectable spring means seated on each of said supports, each said spring means having a plane of deflection at the level at which the spring supports are pivotally fixed to the lower links of the swing hangers; and a bolster extending laterally across said truck, said bolster being supported by the spring means at the opposite sides of the truck.

3. The railway truck of claim 2, together with stop means for limiting lateral movement of said bolster relative to said truck frame.

4. The railway truck of claim 2, wherein each swing hanger includes a second lower link pivotally fixed to said upper link and to said spring support in laterally spaced relation to the first-mentioned lower link.

5. The railway truck of claim 2, wherein each of said laterally deflectable spring means comprises an inner coil spring, and outer coil spring surrounding the inner coil spring, and an air bellows surrounding the outer coil spring.

6. A railway truck comprising front and rear wheel and axle assemblies; a truck frame including laterally spaced apart side frames supported from said wheel and axle assemblies; spring support means at each side of said truck; swing hangers supporting said spring support means from said side frames; a bolster; and vertically extending, laterally deflectable spring means disposed on said spring support means for supporting said bolster therefrom, for cushioning lateral movements of the bolster relative to the side frames, and for providing a laterally acting force for restoring the bolster to a centered position relative to said side frames, the upper ends of said spring means being fixed for movement with said bolster and the lower ends thereof being fixed for movement with said spring support means.

7. The railway truck of claim 6, together with lateral and vertical shock absorbers and radius rods connected between said bolster and said truck frame for cushioning relative movement between said bolster and said truck frame.

8. A railway truck including a frame comprising a first frame section having a first side frame and a first transom rigid with said first side frame and extending laterally therefrom, a second frame section having a second side frame and a second transom rigid with said second side frame and extending laterally therefrom, said second transom being spaced from said first transom longitudinally of the truck; wheel and axle assemblies journalled in said frame sections at opposite ends of the truck and providing wheels at locations corresponding generally to the four corners of said truck; first and second means for so connecting said first frame section to said second frame section as to permit vertical displacement of any one of said wheels relative to the remaining wheels while maintaining said side frames substantially in rectangular and vertical tram, said first and second connecting means confining the relative movement between said first and second frame sections to an axis extending diagonally across said truck through said first and second connecting means; spring seats at each side of said truck; swing hangers supporting said spring seats from said side frames, each said swing hanger comprising an upper link pivotally supported from the associated side frame and a lower link pivotally connected to the first link and pivotally connected to the associated spring seat; a bolster extending laterally across said truck; and coil spring means on the spring seat at each side of said truck supporting said bolster, the inflection of said coil spring means as said bolster moves laterally relative to said side frame being at generally the same level as the pivot connections between the lower links of the swing hangers and the spring supports.