BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view showing a presently preferred embodiment of the hand brake lever for a railway car hand brake system connected to the railway car brake system and connected to the hand brake chain;
FIG. 2 is a perspective enlarged view showing the hand brake lever illustrated in FIG. 1;
FIG. 3 is a top view of the hand brake lever illustrated in FIGS. 1-2; and
FIG. 4 is a cross-sectional view of the hand brake lever taken along lines 4-4 in FIG. 3.
BRIEF DESCRIPTION OF A PRESENTLY PREFERRED EMBODIMENT OF THE INVENTION
Prior to proceeding to the more detailed description of the invention it should be noted that, for the sake of clarity and understanding, identical components which have identical functions have been identified with identical reference numerals throughout the several views illustrated in the drawing Figures.
Referring to FIGS. 1-4 of the drawings, there is shown a railway car brake system, generally designated as 20, including a pair of spaced-apart parallel brake beams 22 and 24 that are adapted to be mounted on the truck 10 of a railway car (not shown) by guide feet 26 that are formed on removable brake heads 28 of the respective beams. The brake heads 28 are mounted on the ends of the brake beams 22, 24 and carry brake shoes 30 for engagement with the wheels 12 of the railway car truck 10. Guide channels (not shown) in the side frames 16, 18 of the truck bolster 14 are arranged to receive the brake beam guide feet 26 in a well-known manner in order to support the brake beams 22, 24 and to guide the brake shoes 30 into proper braking engagement with the wheel treads.
Brake beams 22 and 24 may be a conventional, truss design comprising a compression member 32, a tension member 34, and a strut member 36. The compression and tension members 32 and 34 are welded together at their outer extremities to which brake heads 30 are removably-fixed, as by rivets or other suitable fasteners. Strut member 36 is rigidly-connected between the compression and tension members at their midpoints. Being of relatively lightweight construction, such design is well-known to provide a low-cost brake beam capable of supporting high brake forces.
In the preferred construction of brake beams 22 and 24, as employed in the present invention, the brake beams are bent at their midpoint so as to be V-shaped, as disclosed in U.S. Pat. No. 4,830,148, and assigned to the assignee of the present invention. Such an arrangement better accommodates mounting of the brake rigging components without encountering interference with the brake beam members, while at the same time allowing the brake application force to be applied in line with the brake shoe force to avoid brake beam torque.
Pivotally-mounted by a pin 38 on an upraised portion of strut member 36, in the proximity of tension member 34, is an elongated transfer lever 40 associated with brake beam 22. The pin 38 is received within an aperture 39 which is formed through the transfer lever 40 and which is disposed intermediate its outer ends. Similarly, an elongated transfer lever 42 is pivotally-mounted by a pin 44 to an upraised portion of strut member 36 associated with brake beam 24. In mounting these transfer levers 40 and 42 above the tension member 34, the transfer levers 40 and 42 may be located in proximity with the tension member of the respective beams without encountering interference therewith upon rotation of the transfer levers. The aforementioned bent-beam concept allows the transfer levers 40, 42 to be upraised from the beam midpoint, while still maintaining these levers in a plane common to the brake beam ends, at which point the brake shoe force is applied without imparting braking torque to the beam.
Corresponding opposed ends of transfer levers 40 and 42 are interconnected through force-transmitting members 46 and 48.
Force-transmitting member 46 may be a simple connecting rod or, as shown here, a slack adjuster mechanism 50, such as the slack adjuster mechanism disclosed in U.S. Pat. No. 4,662,485, assigned to the assignee of the present invention. The teaching of U.S. Pat. No. 4,662,485 is incorporated into this document by reference thereto. One end 52 of the slack adjuster body is connected to a first end 54 of the transfer lever 40 by a pin 56 received within an aperture 57 formed through such transfer lever 40 and disposed adjacent and spaced from the first end 54, while the opposite end 58, associated with an actuating rod 60 that is axially movable relative to the slack adjuster housing, is connected by a pin 62 in a similar manner to a first end 64 of transfer lever 42. A slack adjuster trigger mechanism 67 is pivotally-mounted to the slack adjuster housing and is connected to the transfer lever 40 by a pin 68 which is received within an aperture 69 formed through such transfer lever 40 and disposed intermediate the apertures 57 and 39.
Force-transmitting member 48 includes a pneumatic brake actuator device, such as a conventional, piston-type brake cylinder 70 shown in FIGS. 1-2 or an expansible air bag actuator disclosed in U.S. Utility patent application Ser. No. 10/645,035 filed on Aug. 21, 2003. This application is assigned to the assignee of the present invention and its teaching is incorporated into this document by reference thereto.
Brake cylinder 70 is suitably mounted to the brake beam 22 by being bolted or otherwise fixed to the beam compression member 32, at a location on one side of strut member 36 between compression member 32 and tension member 34. Alternatively, brake cylinder 70 may be carried by the brake system 20 without mounting directly to the brake beam, particularly where a lightweight-type brake cylinder, such as the expansible air bag, is employed. With either mounting arrangement, a piston push rod 72 is connected by a pin 74 to a second end 76 of the transfer lever 40. The pin 74 is received within an aperture 78 which is formed through the transfer lever 40. As best shown in FIG. 3, the aperture 78 which enables connecting such brake actuator 70 to the transfer lever 40 is disposed closely adjacent and spaced from the second end 78 of the transfer lever 40.
One end of a connecting rod 80 is connected by a pin 82 to a second end 84 of transfer lever 44. The other end of the connecting rod 80 is pinned to a lug 86 of the brake cylinder 70. This swivel connection accommodates relative vertical and lateral movement of the respective brake beams and associated links without binding at the brake cylinder-connecting rod joint.
Cooperatively arranged with the above-described brake system 20 is a hand brake lever, generally designated as 90, which is connected to the chain 2 and which moves such chain 2 in a direction towards the truck bolster 14 when setting the hand brake (not shown) which is conventionally mounted at one end of the railway car (not shown).
The reader's attention is now directed to FIGS. 3-4. Illustrated therein is the hand brake lever 90 constructed according to a presently preferred embodiment of the invention. Such hand brake lever 90 integrally incorporates the force transfer lever 40 described in details above which is generally horizontally disposed when such hand brake lever 90 is installed in the brake system 20. Accordingly, the transfer lever 40 is hereinafter referred to as a first elongated portion 40 of the hand brake lever 90. The first elongated portion 40 has each of a first predetermined length, a first predetermined thickness and a first predetermined shape. Briefly, the plurality of apertures 39, 57, 72 and 78 are formed though such first elongated portion 40 for enabling connection of the hand brake lever 90 to each of the brake beam 22, the slack adjuster mechanism 50, the brake actuator 70, and the slack adjuster trigger mechanism 68 respectively. In order to achieve movement of the hand brake lever 90 in a direction towards the truck bolster 14 when setting the hand brake (not shown), the aperture 57 which enables connecting such slack adjuster mechanism 50 to the first elongated portion 40 of the hand brake lever 90 is disposed adjacent and spaced from the first end 54 of the first elongated portion 40 of the hand brake lever 90. The aperture 78 which enables connecting such brake actuator 70 to the first elongated portion 40 of the hand brake lever 90 is disposed closely adjacent the second end 76 of the first elongated portion 40 of the hand brake lever 90. The aperture 39 which enables connecting such brake beam 22 to the first elongated portion 40 of the hand brake lever 90 is disposed intermediate each end of the first elongated portion 40 of the hand brake lever 90 and adjacent the aperture 78 for connecting such brake actuator 70 to the first elongated portion 40 of the hand brake lever 90. Finally, the aperture 69 which enables connecting such slack adjuster trigger mechanism 67 to the first elongated portion 40 of the hand brake lever 90 is disposed intermediate the aperture 57 which enables connecting such slack adjuster mechanism 50 and the aperture 39 which enables connecting such brake beam 22 to the first elongated portion 40 of the hand brake lever 90.
In a particular reference to FIG. 3, a portion 94 of a truck bolster facing edge 92 of the first elongated portion 40 of the hand brake lever 90 tapers at a predetermined angle in a direction towards a longitudinal axis of the first elongated portion 40 of the hand brake lever 40. The tapered portion 94 starts adjacent the first end 54 of the first elongated portion 40 and ends between the aperture 69 which enables connecting such slack adjuster trigger mechanism 67 to the first elongated portion 40 of the hand brake lever 90 and the aperture 39 which enables connecting such brake beam 22 to the first elongated portion 40. It has been found that the tapered edge portion 94 is required for positioning the slack adjuster mechanism 50 to the left of the brake actuator 70, as best shown in FIGS. 1-2 and for providing operable clearances in a horizontal plane with at least one of a bifurcated end 52 of such slack adjuster mechanism 50 and a bifurcated end member of such slack adjuster trigger mechanism 67.
Now in a particular reference to FIG. 4, there is illustrated a recess 96 which is formed in a top surface of the first elongated portion 40 and which is disposed intermediate the aperture 39 which enables connecting such brake beam 22 to the first elongated portion 40 and the first end 54 of the first elongated portion 40 of the hand brake lever 90. The recess 96 reduces the first predetermined thickness of the first elongated portion 40 of the hand brake lever 90. It has been found that in order to consistently achieve required brake shoe force without fatiguing the hand brake lever 90, the first predetermined thickness of the first elongated portion 40 should be about 1.0 inch. This presented a problem in connecting slack adjuster mechanism 50 since a conventional opening in a bifurcated end 52 of the slack adjuster mechanism 50 is configured for a mating with a conventional 0.75 thick transfer lever and is formed between about 0.813 inches and about 0.873 inches. It has been further found that such conventional thickness of about 0.75 inches employed with conventional transfer levers resulted in greater than desirable twisting of the slack adjuster mechanism 50 due to mating clearances between the first elongated portion 40 and the bifurcated end 52. Similar fit problem was experienced in connecting the slack adjuster trigger mechanism 67 to the first elongated portion 40 having thickness of about 1.0 thick. Accordingly, it has been found necessary to form a recess 96 in the portion of the first elongated portion 40 to between about 0.795 inches and about 0.805 inches in order to provide for a predetermined fit of the first elongated portion 40 of the hand brake lever 90 within a bifurcated end 52 and, more particularly, to reduce twisting of the slack adjuster mechanism 50 and eliminate fatiguing of the hand brake lever 90 during continuous use. Thus, the aperture 57 which enables connecting such slack adjuster mechanism 50 to the first elongated portion 40 of the hand brake lever 90 and the aperture 69 which enables connecting such slack adjuster trigger mechanism 67 to the first elongated portion 40 of the hand brake lever 90 are formed through the reduced thickness of the first elongated portion 40 of the hand brake lever 90.
In further reference to FIGS. 1-4, there is illustrated a second elongated portion 100 which is connected at a first end 102 thereof to the first end 54 of the first elongated portion 40 of the hand brake lever 90. The second elongated portion 100 is disposed in a generally vertical direction and at a predetermined angle so that a second end 104 of the second elongated portion 100 is spaced at a predetermined distance from such truck bolster 14 when the hand brake lever 90 is installed in such brake system 20. The second elongated portion 100 has each of a second predetermined length, a second predetermined thickness and a second predetermined shape. An aperture 106 is formed through the second elongated portion 100 closely adjacent the second end 104 thereof to enable connection of such hand brake chain 2 to the hand brake lever 90, as best shown in FIG. 1. In operation to set the hand brake (not shown), the second elongated portion 100 moves toward the truck bolster 14 carrying a distal end of the hand brake chain 2 therewith. The presently preferred second predetermined thickness of the second elongated portion 100 is about 1.0 inch being identical to the first predetermined thickness of the first elongated portion 40.
Although the second elongated portion may be welded to the first elongated portion, the hand brake lever 90 is preferably manufactured as a single piece construction by a stamping or a casting method from AISI 4140 steel plate and heat treated to between about 33 RC and about 39 RC.
As was demonstrated during a conventional brake shoe test on a 70 ton truck, the hand brake lever 90 constructed according to the embodiments of the present invention generated required brake shoe force of about 28,000 pounds with a 3,000 pound input from the hand brake.
Thus, the present invention has been described in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same. It will be understood that variations, modifications, equivalents and substitutions for components of the specifically described embodiments of the invention may be made by those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims.
Patent Application
20080035432
