Abstract
A rail vehicle with two sideframes and a bolster as the freight car truck has limits on stability. A railway freight car truck having a friction shoe with a constant force device acting directly on the shoe flat surface is provided, such that the friction shoe is forced to remain in contact with the side frame mating vertical surface. The control spring acting on the friction shoe which applies a varying force to the side frame mating surface. The damping of the friction shoe is retained when there is less variable force of friction, which decreases vertical acceleration of the rail vehicle, providing high speed stability for most track conditions.
Claims
1. A railway car truck comprising a sideframe having a substantially upright column partially defining a center opening, a bolster having an end supported in the sideframe center opening for vertical movement therein, a vertical surface on the sideframe column, and a first wear plate attached to the vertical surface on the sideframe column, sloped surfaces on the bolster, a friction shoe comprising a substantially vertical surface and a sloped surface extending at an acute angle with the vertical surface, a vertical spring urging the friction shoe sloped surface into engagement with the first wear plate on the sideframe column and with the sloped surface of the bolster, and a horizontal spring urging the friction shoe vertical surface into engagement with the first wear plate on the sideframe column.
2. The railway truck of claim 1 wherein the horizontal spring provides a constant lateral force urging the friction shoe vertical surface into engagement with the first wear plate on the sideframe column.
3. The railway truck of claim 1 wherein the vertical spring provides a variable force urging the friction shoe sloped surface into engagement with the sloped surface of the bolster.
4. The railway truck of claim 1 wherein the friction shoe provides both constant and variable damping to vertical movement of the bolster in the sideframe center opening.
5. The railway truck of claim 4 wherein the friction shoe provides forces acting on the bolster to assist in keeping the bolster in a transverse relationship to the sideframe.
6. The railway truck of claim 4 wherein the friction shoe provides forces acting on the bolster to assist in keeping the bolster and sideframe from moving into a parallelogram relationship.
7. A railway car truck comprising a sideframe having a substantially upright column partially defining a center opening, a bolster having an end supported in the sideframe center opening for vertical movement therein, a vertical surface on the sideframe column, sloped surfaces on the bolster, a friction shoe comprising a substantially vertical surface and a sloped surface extending at an acute angle with the vertical surface, a spring urging the friction shoe sloped surface into engagement with the vertical surface on the sideframe column and with the sloped surface of the bolster.
8. The railway truck of claim 7 further comprising a first wear plate attached to the vertical surface on the sideframe column.
9. The railway truck of claim 8 wherein the horizontal spring provides a constant lateral force urging the friction shoe vertical surface into engagement with the first wear plate on the sideframe column.
10. The railway truck of claim 7 wherein the vertical spring provides a variable force urging the friction shoe sloped surface into engagement with the sloped surface of the bolster.
11. The railway truck of claim 7 wherein the friction shoe provides both constant and variable damping to vertical movement of the bolster in the sideframe center opening.
12. The railway truck of claim 11 wherein the friction shoe provides forces acting on the bolster to assist in keeping the bolster in a transverse relationship to the sideframe.
13. The railway truck of claim 11 wherein the friction shoe provides forces acting on the bolster to assist in keeping the bolster and sideframe from moving into a parallelogram relationship.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] In the drawings,
[0007] FIG. 1 is a perspective view of a railway freight car truck assembly in accordance with first embodiment of the present invention;
[0008] FIG. 2 is a partial cut away view of a railway freight car truck suspension in accordance with a first embodiment of the present invention;
[0009] FIG. 3 is a partial exploded view of a bolster and friction shoes of a railway freight car truck in accordance with a first embodiment of the present invention;
[0010] FIG. 4 is partial cut away view of the bolster end and friction shoes of a railway freight car truck in accordance with a first embodiment of the present invention;
[0011] FIG. 5 is a detailed partial cross sectional view of the bolster end and friction shoes with the cam per load device of a railway freight car truck in accordance with a first embodiment of the present invention.
DETAILED DESCRIPTION
[0012] Referring now to FIG. 1, is a perspective view of a three piece railway freight car truck assembly 1 is seen to be comprised of two laterally spaced side frames 7 between which bolster 8 extends. Bolster 8 is seen to include bolster ends 11, which extend through side frame 7 openings 14. Suspension springs 13 support bolster end 11 as well as friction shoes 12. Friction shoes 12 provide vertical damping in the form of sliding resistance between the side frames 7 and bolster 8. Bolster 8 is seen to include on its upper surface a bolster center bowl 10, and a pair of laterally spaced side bearings 9. Wheelset 5 consist of two wheels 2 pressed on an axle 3. Wheelset 5 has axle roller bearings 4 mounted at both ends of axle 3. The wheelset 5 bearings 4 support the side frames 7 on bearing connectors 6.
[0013] Referring now to FIG. 2, is a detailed cut away view of a traditional three piece railway freight truck suspension is shown with detailed partial views of bolster 8 and side frame 7 in partial section. Bolster ends 11 extend through side frame opening 14 which are supported by suspension springs 13. Suspension springs 13 consist of load springs 18 which support the bolster 8 and rail vehicle. Suspension springs 13 also include the control springs 17 that support friction shoes 12 that have a sloped surface bearing against a complementary sloped surface forming bolster angular pocket 20. The suspension springs 13 are compressed by the rail vehicle weight, lading, and track perturbations that occur when the rail vehicle is in transit. Damping is the result of the wedge force on the friction shoe 12 flat surface 22 resistance to sliding against and along the wear plate 16 of the side frame 7. The control spring 17 compression and force varies depending on the vehicle weight, lading and track perturbations that displace the rail vehicle vertically during transit. Variable damping is the result of the control spring 17 varying compression and force. The lateral springs 15 bear against the center rib 19 and place a constant force directly into shoes 12 that simultaneously direct the force to friction shoe 12 flat surface 22, which resists the sliding against and along vertical wear plate 16 of the side frame 7. The lateral springs 15 provide compression and force that are constant; therefore constant damping occurs.
[0014] Referring now to FIG. 3 a partial exploded view of bolster 8 and friction shoes 12 is shown. Friction shoe 12 is cast of steel or iron. The friction shoe 12 has a recessed surface 22 to hold the friction shoe insert 29. The friction shoe insert 29 is a composite or metallic material. The friction shoe 12 on its angled surface 21 has recesses 23 to retain lateral springs 15. The lateral springs 15 protrude through apertures 24 in the bolster angled pockets 20. The lateral springs 15 are preloaded and retained by cam 25 that are inserted through the bolster end 11 retaining holes 27 and the friction shoe 12 retaining holes 28. The cam 25 has a socket 26 on the end. Cam 25 with socket 26 are used to preload lateral springs 15.
[0015] Referring now to FIG. 4 is detailed cut away of the bolster end 11 and friction shoes 12 with the cam 25 per load device. The lateral springs 15 are preloaded and retained by cam 25 that is inserted through the bolster end 11 retaining holes 27 and the friction shoe 12 retaining holes 28. The cam 25 has a socket 26 on the end. Once the cam 25 is in place, it can be turned 90 degrees in retaining holes 27 and the friction shoe 12 retaining holes 28. The rotation of 90 degrees extend cam 25 against friction shoe 12 which in turn compress lateral springs 15. Once the bolster 8 is assembled into the side frames 7, the cam 25 with socket 26 can be turned 90 degrees and the lateral springs 15 will apply a constant force on friction shoe 12.
[0016] Referring now to FIG. 5 is a section of the bolster end 11 and friction shoes 12 with the cam 25 per load device. The lateral springs 15 are preloaded and retained by cam 25 that is inserted through the bolster end 11 retaining holes 27 and the friction shoe 12 retaining holes 28. The cam 25 has a socket 26 on the end. Once the cam 25 is in place, it can be turned 90 degrees in retaining holes 27 and the friction shoe 12 retaining holes 28. The rotation of 90 degrees extend cam 25 against friction shoe 12 which in turn compress lateral springs 15. Once the bolster 8 is assembled into the side frames 7, the cam 25 with socket 26 can be turned 90 degrees and the lateral springs 15 will apply a constant force on friction shoe 12.
