US2749849A

US2749849A - Street railway truck

Info

Publication number: US2749849A
Application number: US295420A
Authority: US
Inventors: William T Rossell
Original assignee: Transit Research Corp
Current assignee: Transit Research Corp
Priority date: 1952-06-25
Filing date: 1952-06-25
Publication date: 1956-06-12
Anticipated expiration: 1973-06-12

Description

June 12, 1956 w. T. ROSSELL 2,749,849

STREET RAILWAY TRUCK Filed June 25, 1952 2 Sheets-Sheet 1 ATTORNEY g r 2,749,849 1C6 Patented June 12, 1956 STREET RAILWAY TRUCK William T. Rossell, New York, N. Y., assignor to Transit Research Corporation, New York, N. Y., a corporation of New York Application June 25, 1952, Serial No. 295,420

Claims. (Cl. 105-193) This invention relates to rail trucks of the type particu larly adapted for use as a part of street railway cars and has for its object to provide a construction which will be sturdy and reliable, economical to build and which will have a high order of riding comfort.

Another object is to provide a bolster springing system which, when mounted on a truck frame and axles of the type above described, will cause a car body to oscillate at low frequencies both vertically and laterally and hence which will give good riding comfort by eliminating high frequencies and violent reactions to track irregularities.

Another object of the invention is to provide mechanical friction means for damping the swinging movements of the truck bolster proportionate to the amplitude of those movements. As will be seen hereinafter with reference to the drawings, the damping means, preferably, does not begin to function until after the bolster has moved from its normal centered position and hence does not transmit vibrations therethrough when the body is centered. Further, substantial precautions are taken to insure the damping means against becoming a part of the spring ing system as it has been found that substantially better results are obtained by relying on the springs alone for all springing functions.

7 Other objects and advantages will become hereinafter more fully apparent as reference is had to the accompanying drawings wherein my invention is illustrated and in which Figure l is a top plan view of a rail truck constructed in accordance with my invention,

Figure 2 is a side elevation of the truck of Figure l with the near wheels removed and with a portion of the ends of the near main frame broken away,

Figure 3 is a perspective view of the rubber sleeve surrounding one end of each of the axle housings of Figures 1 and 2,

Figure 4 is a vertical section taken along the line 44 of Figure 1,

Figure 5 is a vertical section taken along the line 55 of Figure 1, and

Figures 6 and 7 are elevations of the exterior surfaces of the upper and lower spring caps of the main springs shown in Figure 5.

More particularly, the numeral 1 designates the two main side frames of the truck which are connected by axle housing 2. Within the axle housings 2 are axles 3 which are fixed in the hub portions of wheels 4.

The axles are provided with gear sets (not shown) which are rotated by propeller shafts 5 driven by main motors 6. The motors 6 are carried by the cross members 7 each of which is pivotally connected at one end to a hinge pin 8 mounted on a side frame 1 and supported at its other end by springs 9.

The main side frames 1 are each connected at one end 11 to one axle housing 2 by a clamp 12. Between each end 11 with its clamp 12 and the axle 2 is interposed a sleeve 13 of resilient material such as rubber. It is to be noted that this sleeve is composed of two halves, each of which has a circumference less than so that the two halves do not meet around the journal bearing 14. The sleeve halves are so placed that the gaps between their ends are horizontal, thus permitting a slight resiliency between the axles 3 and the ends 11 of the main frames, and this resiliency is increased by providing holes 15 through the sleeve halves. It should be noted that the holes 15 are found only in the vicinity of the ends of the sleeve halves since the relative motions thus provided are limited to fore and aft direction only. If no resiliency, or if insufficient resiliency is provided at these points, there will be undue wear of certain Wheel flanges, while if the resiliency is too great, the truck will hunt. I have found that the resiliency thus provided should permit a relative fore and aft movement between the axles 3 and "the frame ends 1.1 not less than ten one-thousands of an inch and not more than one-sixteenth inch. The frame ends 11 are found at diagonally opposite corners of the truck, the other two corners being rigidly maintained as right angles by securing the frame end 16 securely and directly to the axle housings 2. The axles should have no sliding movement in their journal bearings and the journal bearings have no lateral movements with respect to the side frames 1.

The bolster 17 is supported at each end by two sets of springs, as best seen in Figure 5. One set of

springs

18 and 19 are preferably of the nested coil type, which are provided with spring caps 20 and 21. Each spring cap has knife edge or rocker 22 outwardly thereof for supporting contact with the bolster and side frame 1, respectively. The other spring set is preferably composed of a rubber spring 23 surrounded by a coil spring 24. These springs also have spring caps 25, each having knife edges or rockers 26 outwardly thereof for supporting contact with the bolster 17 and a side frame 1. The

springs

18, 19, 23 and 24 should be so adjusted and proportioned that the rubber spring 23 is but very lightly deflected under empty body loading and the springs should also be so proportioned that their joint load deflection ratio increases directly with increased vertical deflection. The body supported by the bolster will then have a natural frequency of oscillation which remains constant during varying body loads.

The

knife edges

22 and 26 should be rotated to positions to obtain restoring forces of low value in response to lateral swinging movements of the bolster. As illustrated, the rockers 26 may be parallel with each other and parallel to the direction of travel of the truck, so that the rubber spring 23 merely tilts and furnishes no restoring force at all, while the rockers 22 are set at a substantial angle with respect to the center line of the bolster and the direction of truck travel. If the rockers 22 are thus set angularly but parallel to each other they will tend to deflect the bolster out of its normal path of swinging movement and will increase the pressure of the ends of the bolster against hard friction elements 27 which are backed by the rubber 28. It is detrimental to the springing system if the elements 27 are capable of resilient movement since they will yield. These elements are therefore composed of cast iron or, preferably, of an automotive type brake block material, with just sufiicient rubber to intercept short wave vibrations en route from the wheels through the frame. These elements 27 thus act as snubbers and also as a means for transmitting accelerating and decelerating forces from the axles 3 to the bolster 17 without changing the characteristics of the springing system.

The rockers 22 may be set at angles other than parallel with each other, as for instance as illustrated in Figure 6 with different effects on the restoring force supplied by the

springs

18 and 19 and the rockers 26 may also be given a partial rotation either remaining parallel with each other or not. This bolster supporting system is thus capable of simple adjustment to accommodate the trucks to difierent types of service which are often encountered in a single city.

The bolster 17 has a deep center pot 29 with a center bearing 30 at the upper end thereof. Any movement of the supported body thus causes movement of the bolster,

which finds immediate response in the springing system.

Various alterations may be made Without departing from the spirit of my invention and I therefore desire to be extended protection as defined by the appended claims.

What I claim is:

1. In a rail truck, a truck frame comprising two main side members and axle housings acting as frame cross members, a swing bolster, and spring assemblies supporting each end of said bolster from said side members, said spring assemblies each comprising at least one spring having a spring cap at each end thereof, the caps of each said assembly having rockers on the surfaces thereof outwardly of their spring, at least one of said rockers of each assembly being angularly disposed with respect to the length of said side frames and with respect to the direction of swing of said bolster.

2. In a rail truck, a truck frame comprising two main side members and axle housings acting as frame cross members, a swing bolster and spring assemblies each comprising at least one spring having a spring cap at each end thereof, the caps of each said assembly having rockers on the surfaces thereof outwardly of their spring, said rockers of each assembly being parallel to each other and angularly disposed with respect to the direction of swing of said bolster and to the length of said side members whereby said bolster is slightly deflected out of its normal path of swing.

3. In a rail truck, a truck frame comprising two main side members and axle housings acting as frame cross members, a swing bolster and spring assemblies supporting each end of said bolster from said side members, said spring assemblies each comprising at least one spring having a spring cap at each end thereof, the caps of each said assembly having rockers on the surfaces thereof outwardly of their spring, said rockers of each assembly being parallel to each other and angularly disposed with respect to the direction of swing of said bolster and to the length of said side members whereby said bolster is slightly deflected out of its normal path of swing, and hard friction elements supported by said side members against which the ends of said bolster press during their swinging, movements.

4. In a rail truck, a truck frame comprising two main side members and axle housings acting as frame cross members, a swing bolster and spring assemblies supporting each end of said bolster from said side members, said spring assemblies each comprising at least one spring having a spring cap at each end thereof, the caps of each said assembly having rockers on the surfaces thereof outwardly of their spring, said rockers of each assembly being parallel to each other and angularly disposed-with respect to the direction of swing of said bolster and to the length of said side members whereby said bolster is slightly deflected out of its normal path of swing, and non-resilient friction elements supported by said slide frames against which the ends of said bolster presses during its swinging movement, said friction elements having resilient pads between each thereof and said side frame to prevent the free transmission of high frequency vibrations therethrough to said bolster.

5. In a rail truck, a truck frame, a bolster mounted on springs for lateral swinging movements with respect to said frame and freely movable at or near its centered position, snubbing means for damping the lateral movements of said bolster composed of non-resilient material, means including a resilient pad supporting said snubbing means on said truck frame, spring caps on each end of each of said springs, and angularly displaced rockers on the surfaces of said caps outwardly of said springs comprising a part of the bolster mounting, said rockers by their angular disposition with respect to the direction of swing of said bolster causing said bolster to engage said snubbing means with pressures proportionate to the amplitude of the swinging movements.

References Cited in the file of this patent UNITED STATES PATENTS Travilla, Jr. et al. Sept. 15, 1953