Railroad car truck damper wedge fittings

Patent metadata

Field	Value
Publication number	US-11807282-B2
Application number	US-202017092771-A
Country	US
Kind code	B2
Filing date	Nov 9, 2020
Priority date	Nov 9, 2020
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

There is a damper wedge for a railroad car truck. It has a removable and replaceable friction element that reciprocates on the wear plate of the side frame column of the railroad car truck. It has a non-metallic wear surface; a spring seat that, in use, engages a spring of the railroad car truck; and an inclined damper wedge surface having a primary angle, alpha, and a secondary angle, beta. The inclined damper wedge surface has a curvature. The curvature has a working point. The working point is located in a central region of a contact patch, or working surface patch. The nonmetallic wear surface material is mounted to a carrier that mounts removably to the damper wedge body. The carrier has fingers that span the wedge and that transfer shear and resist torsion, the fingers preventing the non-metallic member from migrating out of position.

First claim

We claim:

1. A friction pad assembly that engages a seat of a friction damper wedge body that mounts in a bolster pocket of a truck bolster of a railroad car truck, wherein said friction pad assembly comprises:
a retainer and a mating friction pad that engages said retainer;
said retainer having a first interface that engages said friction pad; and
said retainer having a second interface that engages the seat of the friction damper wedge;
said retainer being releasable from the seat of the friction damper wedge body to permit replacement of said friction pad assembly;
said friction pad being releasable from said retainer; and
when said friction pad is engaged with said retainer, and said retainer is engaged with the seat, said retainer is resiliently deflected by being engaged with said friction pad and with the seat.

2. The friction pad assembly of claim 1 wherein engagement of said friction pad with said retainer imposes a first friction fit; engagement of said retainer with said seat imposes a second interference fit; and mating said retainer with said seat tightens said first friction fit.

3. The friction pad assembly of claim 1 wherein mating engagement of said friction pad with said retainer imposes a spring pre-load on said retainer; and mating of said retainer with said seat increases said spring pre-load.

4. The friction pad assembly of claim 1 wherein said friction pad has a first characteristic dimension; said seat has a second characteristic dimension; there is a dimension delta that is the difference between said first and second characteristic dimensions; said retainer includes a spring, and said spring is deflected to conform to said first characteristic dimension and said second characteristic dimension, and, when so deflected, said spring acting to retain said friction pad in position relative to said seat.

5. The friction pad assembly of claim 1 in which the seat of the damper wedge defines a socket, and wherein said friction pad is sized to seat within said socket with a clearance, said retainer occupies said clearance; and, when said retainer is seated in said clearance said retainer is resiliently loaded between the seat of the damper wedge and said friction pad.

6. The friction pad assembly of claim 5 wherein said retainer has a spider and an array of fingers spaced around said spider, said fingers defining springs that are engaged when the friction pad is installed.

7. The friction pad assembly of claim 6 wherein said springs collectively define a compression spring that, on installation, works between, and against, the friction pad and the friction damper wedge body.

8. The friction pad assembly of claim 6 wherein said springs have a form of a dog-leg in which one part of the dog-leg bears against said friction pad and another part of the dog-leg engages the damper wedge body, and installation of said friction pad results in deflection of said dog-leg between the damper wedge body and said friction pad.

9. The friction pad assembly of claim 8 wherein said dog-leg has a fulcrum, and said fulcrum bears against said friction pad.

10. The friction pad assembly of claim 6 wherein said friction pad is four sided and at least one of said springs bears on each of said four sides.

11. A retainer operable to work between a friction pad and a seat of a friction damper wedge body that mounts in a bolster pocket of a truck bolster of a railroad car truck, wherein said retainer comprises:
a first interface at which said retainer engages the friction pad;
a second interface at which said retainer engages the seat of the friction damper wedge;
said retainer being releasable from the seat of the friction damper wedge to permit replacement of the friction pad;
the friction pad being releasable from said retainer; and
when the friction pad is engaged with said retainer, and said retainer is engaged with said seat, said retainer is resiliently deflected by being engaged with the friction pad and with the seat.

12. The retainer of claim 11 wherein said retainer is sized such that when the friction pad is mounted in the retainer said first interface is in a friction fit with the friction pad.

13. The retainer of claim 11 wherein said retainer is sized such that when said retainer engages the seat of the friction damper wedge body, said second interface of said retainer is in a friction fit.

14. The retainer of claim 11 wherein said retainer is sized such that when the friction pad is engaged by said first interface, said retainer has a resilient spring loading.

15. The retainer of claim 11 wherein said retainer is sized such that when the seat of the damper wedge body is engaged by the second interface, said retainer is resiliently spring loaded by that engagement.

16. The retainer of claim 11 wherein said retainer is sized such that at least two of:
when the friction pad mounts to said retainer said first interface is in a first friction fit with the friction pad;
when said retainer engages the seat of the friction damper wedge body, said second interface of said retainer is in a second friction fit; and
when the friction pad is engaged by said first interface, and the seat of the damper wedge body is engaged by the second interface, said retainer is resiliently spring loaded between the friction pad and the seat of the damper wedge body.

17. The retainer of claim 11 wherein said retainer has at least a first finger, said finger locates between the friction pad and the seat of the damper wedge body on installation; said first finger defines at least a portion of said first interface of said retainer at which said finger engages the friction pad; said first finger defines at least a portion of said second interface of said retainer at which said first finger engages the seat of the friction damper wedge; and, said first finger defines a spring that is deflected on installation.

18. The retainer of claim 11 wherein said retainer has a spider, and a set of fingers arrayed peripherally relative to said spider; said set of fingers defines at least a portion of said first interface, at which said set of fingers engages the friction pad; said set of fingers defines at least a portion of said second interface, at which said set of fingers engages the seat of the friction damper wedge; in use said set of fingers is resiliently spring loaded between the friction pad and the seat of the friction damper wedge.

19. The retainer of claim 18 , in which the friction pad is a non-metallic friction lining that has a front face for engaging a friction wear plate of a side frame column of a railroad car truck side frame, a rear face for orientation facing the damper wedge, and side edges extending between the front and rear faces; in which the seat of the friction damper wedge body is a socket, the socket being sized to accommodate the friction pad; and wherein, on installation:
said spider of said retainer locates in the socket behind the rear face of the friction pad and is trapped between the rear face of the friction pad and the seat of the friction damper wedge body;
said set of fingers grasps respective ones of the side edges of the friction pad, said set of fingers being spring-loaded thereby;
said set of fingers fits within said socket, and is further spring-loaded thereby; and
spring loading of said retainer between the friction pad and the socket discourages dislodgement of the friction pad from the socket.

20. A friction damper wedge assembly comprising the retainer of claim 11 , the friction da

Assignees

• Nat Steel Car Ltd

Inventors

• Hematian Jamal
• Black Kenneth Wayne

Classifications

• B61F5/122 Primary

  with friction surfaces · CPC title

• B61F3/02 Primary

  with more than one axle · CPC title

• B61F5/06

  incorporating metal springs · CPC title