Brake Beam Wear Liner

Abstract

A brake beam wear liner having a base wall extending along a first plane and first and second opposing side walls that extend obliquely from the base wall along second and third planes to be outwardly offset a predetermined angle. One or more detents may be positioned on the outside of the side walls to maintain the offset angle after installation in a brake beam bracket. The base wall and the first and second opposing walls, as well as first and second flanges extending from the sides walls preferably have a uniform thickness.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional Application No. 61/946,208, filed on Feb. 28, 2014.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to rail car braking systems and, more specifically, to brake beam wear liners for truck mounted and body mounted braking systems.

2. Description of the Related Art

The braking system of a freight car train include a pair of brake beams having brake shoes that, when moved by the brake cylinder, will engage the treads of the wheels to apply braking forces. The brake beams are mounted on the railway car truck so that the ends of the brake beams are received in and allowed to slide along guides formed in the side frames of the trucks. The side frames are typically unitary cast steel structures and the brake beam guides are integrally cast as part of the side frames. Brake beam wear liners are positioned within the brake beam guides to reduce wearing of the side frame and the ends of the brake beam that extend through the guides of the side frame.

Brake beam wear liners are typically be comprised of stamped steel or high density plastics and polymers having sufficient structural strength for railway usage and provide adequate sliding of the ends of the brake beam to reduce wear. Exemplary brake beam wear liners include the Rostuf™ brake beam wear eliminator manufactured by Ross Equipment Australia Pty Ltd of Warriewood NSW 2102 Australia and the WE-5510-XL heavy-duty brake beam guide wear eliminator manufactured by Amsted Rail Company, Inc. of Chicago, Ill. USA. These liners, however, often undergo shaving and the formation of set points in the plastic wear surface of the liner that result in an undesirable amount of clearance between the brake beam ends and the inner wear surface of the liner. This excessive clearance allows the brake beams to rotate from their desired orientation, resulting in brake head misalignment. Thus, there is a need for brake beam wear liners that resist the wearing that leads to excessive clearance and avoids excessive rotation of the brake beam to preserve the proper angle of attack for the brake shoes.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises a brake beam wear liner having a base wall extending along a first plane, first and second opposing side walls extending obliquely from the base wall along second and third planes, respectively, to define an internal trough that extends along an axis that is perpendicular to the first plane. The first and second planes are offset outwardly from the central axis by a predetermined angle. First and second flanges extend outwardly from the first and second opposing side walls, respectively. The base wall, the first and second opposing walls, and the first and second flanges preferably have a uniform thickness. At least one detent may be formed on an outside surface of each of the first and second opposing walls. The detents are dimensioned to engage the brake beam bracket of a rail car truck and hold the liner in place while maintaining the offset of the first and second opposing sidewalls. The liner may be fabricated from nylon, such as glass-reinforced nylon or glass/mineral reinforced nylon. In use, first and second brake beam wear liners are installed in the corresponding first and second brake beam brackets of a rail car and then a brake beam having first and second opposing ends is positioned in the brake beam brackets so that the first and second opposing ends of the brake beam are positioned in the first and second brake beam wear liners, respectively.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross-section of an brake beam wear liner according to the present invention;

FIG. 2 is a top plan of a brake beam wear liner according to the present invention;

FIG. 3 is a front view of a brake beam wear liner according to the present invention;

FIG. 4 is a perspective view of a brake beam wear liner according to the present invention prior to installation in a bracket of a truck side frame receiver; and

FIGS. 5A and 5B identify the locations where certain measurements were taken in connection with identifying the advantages provided by the present invention;

FIG. 6 is a cross-section of a brake beam wear line installed in a bracket and supporting a brake beam according to the present invention;

FIG. 7 is a schematic of the angle of attack of a brake shoe onto a wheel when supported by a brake beam wear liner according to the present invention; and

FIG. 8 is a cross-section of a brake beam wear line installed in a bracket and supporting a brake beam according to the present invention taken along line E-E of FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, wherein like reference numerals refer to like parts throughout, there is seen in FIG. 1 an improved brake beam wear liner 10 that defines an interior trough 12 that extends along an axis X-X and is dimensioned to receive the end of a brake beam and allow the brake beam to slide therein as the brakes are applied. Liner 10 comprises a base wall 14 that extends along a plane A-A perpendicularly to axis X-X to define the bottom of trough 12. A first side wall 16 extends along plane B-B obliquely from one end of base wall so that plane B-B is offset from axis X-X by a predetermined angle α. A second side wall 18 extends along plane C-C obliquely from the opposing end of base wall 14 so that plane C-C is also offset from axis X-X by predetermined angle α. Angle α is preferably about 3.5 degrees for a liner 10 having a base wall 14 of about 2.0 inches and sides walls of about 3.0 inches in length. As seen in FIG. 1, offsetting of first and second side walls 16 and 18 by angle α is outwardly from axis X-X so that trough 12 is wider at its mouth than proximately to base wall 14. First and second flanges 20 and 22 extend outwardly from first and second side walls 16 and 18, respectively, at approximately right angles thereto. Base wall 14, first and second side walls 16 and 18, and first and second flanges 20 and 22 have a predetermined thickness T that extends generally uniformly throughout liner 10. Thickness T is preferably about 0.27 to 0.28 inches for a liner 10 having a base wall of about 2.0 inches and sides walls of about 3.0 inches in length. Thus, thickness T is more than ten percent of the length of base wall 14 and just under ten percent of the length of side walls 16 and 18, which is a nearly a fifty percent increase over the thickness of conventional brake beam liners.

Liner 10 may further comprise at least one detent 24 on the outer surface of side wall 16 and at least one detent 26 on the outer surface of side wall 18. As seen in FIGS. 2 and 3, notches 34 and 36 may be formed in side wall 16 and side wall 18, respectively.

Referring to FIG. 4, detents 24 and 26 are positioned and dimensioned to contact the inside of a brake beam receiving bracket 30 of a truck frame 32 and help hold liner 10 in place in bracket 30. Liners 10 may also include appropriate markings, such as wear liner dash numbers or color coding to identify the corresponding truck frame receiver for which a particular liner 10 is sized and liner 10 can be provided in any variety of sizes and thicknesses to fit standard and oversize truck frames. Liners 10 resist wear and, even when worn, prevent excessive clearance and thus unacceptable rotation of the brake beams.

Liner 10 is preferably formed from any polymer having the appropriate high level of mechanical strength, rigidity, and stability under heat, such as polymers having fiberglass embedded therein. Suitable categories of polymers which may be used to form wear liner 10 include polyamides or nylons, such as PA 6 or Nylon 6, and PA 66 or Nylon 66. For example, wear liner 10 may be formed from Ultramid® polyamide, available from BASF Corporation of Florham Park, N.J. USA. Ultramid® polyamides are molding compounds based on PA 6, PA 66 and copolyamides such as PA 66/6, and have exceptional high mechanical strength, rigidity and thermal stability. Moreover, Ultramid® polyamides also provide good impact resistance, even at low temperatures, as well as advantageous sliding friction properties and problem-free processing.

Wear liner 10 may be injection molded using FRP (or “fiberglass reinforced plastics”) or GRP (or “glass reinforced plastics”). Fiberglass or a combination of fiberglass and mineral reinforcement may be used to enhance the performance characteristics of Ultramid nylon molding compounds. Fiberglass reinforcement improves strength, stiffness, dimensional stability, and performance at elevated temperatures. Glass reinforced grades include HMG10, 50% glass, high modulus; HMG13, 63% glass, high modulus; SEG7, 35% glass; 8230G, 6% glass reinforcement; 8231G, 14% glass; 8232G, 25% glass; 8233G, 33% glass; 8234G, 44% glass; 8235G, 50% glass; HPNTM 9233G, 33% glass reinforced, improved productivity; and 5233G, 33% fiberglass based on nylon 6,6.

Combining fiberglass reinforcement along with impact modification produces compounds that offer increased dry-as-molded impact while maintaining excellent strength and stiffness properties. Products include TG3S, 15% glass, impact modified; TG7S, 34% glass, impact modified; 8331G, 14% glass, impact modified; 8332G, 25% glass, impact modified; 8333G HI, 33% glass, high impact, improved productivity and surface appearance; 8334G, 40% glass reinforced, impact modified; and HPN 9333G, 33% glass reinforced, impact modified, improved productivity. Mineral reinforcement may be used to enhance strength and stiffness properties while maintaining typical chemical resistance associated with Ultramid nylon. Mineral reinforced products include 8260, 40% mineral, chrome plateable; 8360, 34% mineral; and 8362, 34% mineral, impact modified; and HPN 9362, 40% mineral reinforced, impact modified, improved productivity. Mineral and glass reinforcement may also be used to lead to products with an excellent balance of mechanical properties combined with warpage resistance. Mineral/Glass reinforced grades include SEGM35 H1, 40% glass/mineral reinforced; 8262G, 20% mineral/glass reinforced; 8266G, 40% mineral/glass reinforced; and 8267G, 40% mineral/glass reinforced. The amount of such reinforcement may be chosen from about 5% to about 50%, although a nylon 6/6 with 30% glass may be preferred.

An inspection of rail truck side frames according to AAR Specification S-366 (Revision 2009) revealed brake shoe thicknesses as set forth in Table I below.

TABLE I
Brake Shoe Thickness (inches)
	L1	Top	1.007	R1	Top	1.426
		Bottom	1.776		Bottom	1.867
	L2	Top	1.709	R2	Top	1.531
		Bottom	1.406		Bottom	1.369
	L3	Top	1.157	R3	Top	1.128
		Bottom	1.587		Bottom	1.605
	L4	Top	1.705	R4	Top	1.587
		Bottom	1.632		Bottom	1.617

Several dimensional inspection points were taken within the truck side frame receivers from trucks in inventory, both with wear liners and without wear liners. The results of the truck side frame inspections are shown in Table II (without wear liners) and Tables IIIA and IIIB (with new liners) with the testing locations identified in FIGS. 5A and 5B.

TABLE II
Side frame Number (inches)
Point	1	2	3	4	5	6	7	8	9	10
A	2.101	2.092	2.100	2.067	2.060	2.028	2.120	2.065	2.035	2.048
B	2.081	2.066	2.100	2.080	2.065	2.025	2.046	2.118	2.038	2.059
C	2.110	2.086	2.110	2.080	2.024	2.052	2.045	2.093	2.103	2.043
D	2.105	2.092	2.085	2.074	2.059	2.055	2.045	2.068	2.166	2.051
Var.	0.029	0.026	0.025	0.013	0.041	0.030	0.075	0.053	0.131	0.016

TABLE IIIA
Side frame #1 (inches)
	Side frame	A1	A2	D
	Point 1	1.657	1.638	1.641
	Point 2	1.695	1.638	1.690

TABLE IIIB
Side frame #3 (inches)
	Side frame Point	A	D
	Point 1	1.653	1.652
	Point 2	1.642	1.646

Notably, thirteen of the forty measured points were outside of the appropriate AAR specification.

Referring to FIG. 6, improved brake beam wear liner 10, when positioned in bracket 30, will ensure that the brake beam 40 remains oriented so that the brake shoe 42 carried by brake beam 40 evenly engages a wheel 44 as points 46 and 48, as seen in FIG. 7. More particularly, as seen in FIG. 8, liner 10 when positioned in bracket 30 allows for no more than thirteen minutes of deflection from the preferred angle of attack. Conventional liners that allow upwards of one degree of deflection result in misalignment of brake shoe 42 at points 46 and 48, thereby providing an undesirable angle of attack that results in improper wearing of brake shoe 42 to rail wheel 44. Due to its dimensions and composition, liner 10 preserves the desired angle of attack when installed and when used over time.

Although embodiments of the present brake beam wear liner have been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The scope of the present invention is, therefore, to be limited only by the terms of the appended claims.

Claims

1. A brake beam wear liner, comprising:

a base wall extending along a first plane;

first and second opposing side walls extending obliquely from the base wall along second and third planes, respectively, to define an internal trough that extends along an axis perpendicular to the first plane, wherein the first and second planes are offset from the central axis by a predetermined angle;

first and second flanges extending outwardly from the first and second opposing side walls, respectively; and

wherein the base wall, the first and second opposing walls, and the first and second flanges have a uniform thickness that is at least ten percent of the length of the base wall.

2. The brake beam wear liner of claim 1, further comprising at least one detent formed on an outside surface of each of the first and second opposing walls.

3. The brake beam wear liner of claim 2, wherein the detents are dimensioned maintain the offset of the first and second opposing sidewalls when the brake beak wear liner is installed into a brake beam.

4. The brake beam wear liner of claim 1, wherein the base wall, the first and second side walls and the first and second flanges are fabricated from nylon.

5. The brake beam wear liner of claim 4, wherein the nylon comprises a glass-reinforced nylon.

6. The brake beam wear liner of claim 4, wherein the nylon comprises a glass/mineral reinforced nylon.

7. A method of protecting against undesired rotation of a break beam, comprising the steps of:

installing first and second brake beam wear liners in the corresponding first and second brake beam brackets of a rail car, wherein each of the first and second brake beam wear liners comprises a base wall extending along a first plane, first and second opposing side walls extending obliquely from the base wall along second and third planes, respectively, to define an internal trough that extends along a central axis, wherein the first and second planes are offset from the central axis by a predetermined angle, first and second flanges extending outwardly from the first and second opposing side walls, respectively, wherein the base wall, the first and second opposing walls, and the first and second flanges have a uniform thickness; and

installing a brake beam having first and second opposing ends into the rail car to that the first and second opposing ends of the brake beam are positioned in the first and second brake beam wear liners, respectively.

8. The method of claim 7, further comprising at least one detent formed on an outside surface of each of the first and second opposing walls.

9. The method of claim 8, wherein the detents are dimensioned maintain the offset of the first and second opposing sidewalls when the brake beak wear liner is installed into a brake beam.

10. The method of claim 7, wherein the base wall, the first and second side walls and the first and second flanges are fabricated from nylon.

11. The method of claim 10, wherein the nylon comprises a glass-reinforced nylon.

12. The method of claim 10, wherein the nylon comprises a glass/mineral reinforced nylon.