Brakes – Vehicle – Railway
Reexamination Certificate
1999-01-20
2001-08-28
Schwartz, Christopher P. (Department: 3613)
Brakes
Vehicle
Railway
C188S052000, C188S15300R
Reexamination Certificate
active
06279689
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates, in general, to a parking brake arrangement for a railroad vehicle type braking system and, more particularly, this invention relates to an automatic hydraulic type parking brake for a railroad vehicle braking system and, still more specifically, to an automatic hydraulic type parking brake for use on truck mounted brake assemblies.
BACKGROUND OF THE INVENTION
As is generally well known in the railway industry, when railway cars are taken out of a train and parked at a siding or yard, the hand brake or parking brake on at least some of these cars must be applied as a precaution against unwanted and/or unexpected movement of the cars. A typical railway car hand brake system normally consists of an apparatus for manually applying and biasing one or more brake shoes against the tread of one or more wheels of the railway car by either turning a hand wheel or pumping a ratchet handle on a hand brake mechanism attached to the railway car.
As illustrated in
FIG. 2
, in truck mounted braking systems, the hand brake mechanism is usually either a cast or stamped metal gear housing usually attached to an outside end wall of the railway car and having a rotatable chain drum therein which can be rotated by turning the hand wheel to wind a brake chain onto the chain drum. The other end of the brake chain normally extends through the bottom of the gear housing and is interconnected with a cable or other linkage, such as a hand brake lever, to the brake beam which carries the brake shoes such that winding of the brake chain onto the chain drum will apply tension to the brake chain and linkage as will be necessary to draw the interconnected brake shoes against the respective tread surfaces of adjacently disposed railway car wheels and, accordingly, apply the hand brake as intended.
A disadvantage of this prior art type hand brake parking brake arrangement is that operation of the handwheel requires exerting a considerable amount of physical force. Oftentimes this physical force must be exerted from an awkward position. This, in turn, makes the hand brake or parking brake rather difficult to apply and could present a possible serious injury hazard. Still another significant disadvantage of this type of hand brake parking brake arrangement is that it requires an operator to manually apply the hand brake to each individual car, requiring a significant amount of time and labor.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an automatic hydraulic parking brake for a railway vehicle braking system which is an ergonomic alternative to the currently used manually activated hand brake assemblies.
Another object of the present invention is to provide an automatic hydraulic parking brake for a railway vehicle braking system which is particularly applicable to TMX® truck mounted type braking systems. (TMX® is a registered trademark to Westinghouse Airbrake Company, the assignee of the present invention).
Still another object of the present invention is to provide an automatic hydraulic parking brake for a railway vehicle braking system which may be used to replace the currently used manually activated handwheel type hand brakes.
A further object of the present invention is to provide a hydraulic parking brake which may be quickly and easily applied thus providing a reduced chance of injury to the operator applying this brake.
Yet another object of the present invention is to provide a hydraulic parking brake which may be quickly and easily applied thus providing a significant reduction in time and labor.
Briefly, and in accordance with the foregoing objects, the instant invention comprises a hydraulic actuator engaged with a railroad vehicle braking system. This hydraulic actuator will typically be mounted at the rear of the air brake cylinder. The hydraulic actuator includes a hydraulic piston member and a spindle having a first end which is attached to the hydraulic piston member. Both the hydraulic piston member and the spindle are capable of movement in a forwardly and a rearwardly direction upon application of hydraulic pressure thereto. The second end of the spindle enters into an aperture which is provided in the rear of the air cylinder and is capable of contacting the piston of the air cylinder upon activation of and forward movement of the hydraulic piston member.
Movement of the hydraulic piston member and spindle in both a forward direction and a rearward direction is achieved by the application of a hydraulic fluid, such as water or oil, within selected openings in the hydraulic actuator. Forward movement of the hydraulic piston member and the spindle will cause the second end of the spindle to contact and apply a force to the air cylinder piston. This force applied to the air cylinder piston will then cause movement of the air cylinder piston which, in turn, applies a force to the push rod within the air brake cylinder causing movement of the push rod in a forward direction. This forward movement of the push rod applies a force to the force transfer lever which causes the force transfer lever to rotate in a counterclockwise direction to apply a force to the slack adjuster assembly in order to effect activation of the parking brake assembly.
Although a number of objects and advantages of the present invention have been described in some detail above, various additional objects and advantages of the hydraulic parking brake lever arrangement of the present invention will become more readily apparent to those persons who are skilled in the art from the following more detailed description of the invention, particularly, when such detailed description of the invention is taken in conjunction with both the attached drawing figures and with the appended claims.
REFERENCES:
patent: 4175793 (1979-11-01), Clemmons
patent: 4201277 (1980-05-01), Meier et al.
patent: 4662485 (1987-05-01), Kanjo et al.
patent: 5069312 (1991-12-01), Kanjo et al.
patent: 5701975 (1997-12-01), Hawryszkow
patent: 5713261 (1998-02-01), Ring et al.
patent: 5794739 (1998-08-01), Ring et al.
James Ray & Associates
Schwartz Christopher P.
Siconolfi Robert A.
Westinghouse Air Brake Company
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