Patent Application
20150246680
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.
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.
The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:
Referring now to the drawings, wherein like reference numerals refer to like parts throughout, there is seen in
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
Referring to
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.
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
Notably, thirteen of the forty measured points were outside of the appropriate AAR specification.
Referring to
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.
The present application claims priority to U.S. Provisional Application No. 61/946,208, filed on Feb. 28, 2014.
| Number | Date | Country | |
|---|---|---|---|
| 61946208 | Feb 2014 | US |
