Brake system with integrated car load compensating arrangement

• US 7,416,262 B2
• Filed: 06/06/2005
• Issued: 08/26/2008
• Est. Priority Date: 06/09/2004
• Status: Active Grant

• Current Assignee: Wabtec Holding Corp (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: Wabtec Holding Corp (Westinghouse Air Brake Technologies Corporation)
• Inventors: Ring, Michael E.
• Primary Examiner(s): King; Bradley
• Assistant Examiner(s): Rashid; Mahbubur
• Application Number:
  US11/145,738
• Publication Number:
  US 20050275279A1
• Time in Patent Office: 1,177 Days
• Field of Search: 303/22.2, 303/22.5, 303/22.7, 188/153.R, 188/151.R, 137/118.06
• US Class Current: 303/22.2
• CPC Class Codes: B60T 8/185 Arrangements for detecting vehicle level
• CPC Class Codes: B60T 8/1893 especially adapted for railway vehicles

Abstract

A railway car brake system comprising a control device engageable with a predetermined portion of such railway car for compensating braking force in response to a load carried by such railway car. The control device includes a sensor mechanism engageable with a truck bolster or a movable car structure for sensing a vertical position thereof corresponding to a load carried by the railway car. There is a control valve engageable with the sensor mechanism which generates a fluid pressure signal responsive to such load. A pneumatic actuator engageable with a predetermined brake beam disposed on such truck assembly and connected to such control valve. This pneumatic actuator generates a predetermined braking force responsive to the fluid pressure signal and further responsive to the load carried by the railway car as sensed by the sensor mechanism. Such predetermined braking force may be proportionally adjusted to variations in the load carried by the railway car.

Claims

1. A load compensating brake system for a railway car, said load compensating brake system comprising:

(a) a fluid pressure operated control valve including;

(i) a valve operating means mounted for reciprocal motion and having a first end thereof engageable with one of the railway car, at least one of a pair of truck assemblies and a combination thereof for sensing a vertical position of a vertically movable portion of the at least one of a pair of truck assemblies, a vertically movable portion of the railway car and a combination thereof, said vertical position defining a load carried by the railway car, said valve operating means movable between a first position for sensing the railway car carrying an empty load and a second position for sensing the railway car carrying a load greater than said empty load, and

(ii) a valve housing attached to a vertically stationary portion of the at least one of the pair of truck assemblies and having an inlet port connected to a source of fluid pressure, a first outlet port and a second outlet port each being in fluid communication with said inlet port, said valve housing is operable between a first fluid flow condition wherein said fluid pressure flows from said inlet port to a first outlet port and a second fluid flow condition wherein said fluid pressure flows from said inlet port to said first outlet port and said second outlet port, said valve housing receiving a second end of said valve operating means and operable thereby to generate a first fluid pressure signal at said first outlet port, said first fluid pressure signal responsive to said valve operating means being in said first position and generates a combination of said first fluid pressure signal at said first outlet port and a second fluid pressure signal at said second outlet port, said combination responsive to said valve operating means being in said second position; and

;

(b) an actuating means engageable with a predetermined portion of said brake system and a predetermined portion of said control means, said actuating means selectively responsive to said first fluid pressure signal to generate a first braking force and to said combination of said first and said second fluid pressure signals to generate a second braking force associated with the load carried by the railway car and apply one of said first and said second braking force to each wheel of the at least one of pair of truck assemblies.

2. A load compensating brake system for a railway car, according to claim 1, wherein said first fluid pressure signal and said second fluid pressure signal are substantially identical.

3. A load compensating brake system for a railway car, according to claim 1, wherein said control valve means includes a bias spring means for biasing said valve body into said first flow condition.

4. A load compensating brake system for a railway car, according to claim 1, wherein said actuating means includes:

(a) a mounting means attached to a rigid portion of said brake system;

(b) a push rod connectable to at least one linkage member of said brake system;

(c) a first air spring actuator disposed intermediate and connected to said mounting means and said push rod, said first air spring actuator having a first fluid communication means connected to said first outlet port of said control valve means for receiving said first fluid pressure signal, whereby said first fluid pressure inflates said first air spring actuator and generates said first predetermined braking force to be transmitted by said push rod; and

(d) a second air spring actuator disposed intermediate and connected to said mounting means and said push rod, said second air spring actuator having a second fluid communication means connected to said second outlet port of said control valve means for receiving said second fluid pressure signal, said second air spring actuator axially receives said first air spring actuator, whereby said combination of said first fluid pressure signal and said second fluid pressure signal substantially simultaneously inflates said first air spring actuator and said second air spring actuator and generates said second predetermined braking force to be transmitted by said push rod.

5. A load compensating brake system for a railway car, according to claim 1, wherein said actuating means is a cylinder including:

(a) a housing engageable with said railway car brake system and having a first closed end and an opposed second closed end;

(b) a partition rigidly and sealably disposed within said housing intermediate said first closed end and said opposed second closed end;

(c) a cylinder rod disposed for reciprocal movement within said housing and extending through said partition and second closed end, said cylinder rod connectable to at least one linkage member of said brake system at an end extending through said second closed end of said housing;

(d) a first fluid chamber formed intermediate said first closed end and said partition;

(e) a second fluid chamber formed intermediate said partition and said second closed end;

(f) a first piston sealably disposed within said first fluid chamber and attached to said cylinder rod for movement therewith;

(g) a second piston sealably disposed within said second fluid chamber and attached to said cylinder rod for movement therewith;

(h) a first fluid communication means in fluid communication with said first fluid chamber and with said first outlet port of said control valve means for receiving said first fluid pressure signal and supplying it to said first fluid chamber, whereby said first fluid pressure signal moves said first piston and said cylinder rod and generates said first predetermined braking force which is transmitted by said cylinder rod; and

(i) a second fluid communication means in fluid communication with said second fluid chamber and with said second outlet port of control said valve means for receiving said second fluid pressure signal and for supplying it to said second fluid chamber, whereby said combination of said first fluid pressure signal and said second fluid pressure signal substantially simultaneously moves said first piston, said second piston and said cylinder rod and generates said second predetermined braking force which is transmitted by said cylinder rod.

6. A load compensating brake system for a railway car, according to claim 5, wherein said cylinder further includes a spring means having a predetermined spring rate and engageable with one of said cylinder rod, said first piston, said second piston and any combination thereof for controlling one of said first predetermined braking force, said second predetermined braking force and a combination thereof and for returning said first piston and said second piston to an initial non-actuated position during a brake release.

7. A load compensating brake system for a railway car, according to claim 1, wherein said actuating means is a cylinder including:

(a) a casing engageable with said railway car brake system;

(b) a hollow piston assembly mounted for reciprocal movement within said casing, said hollow piston assembly having a hollow portion defined by a back wall and at least one sidewall;

(c) a small piston assembly positioned within said hollow portion, said small piston assembly including a first surface facing said back wall and a peripheral edge portion for sealingly engaging an inner surface of said at least one sidewall;

(d) a first space defined by said back wall of said hollow portion, at least a portion of said inner surface of said at least one sidewall and said first surface of said small piston assembly;

(e) a piston rod assembly having a first end and a second end, said first end being connected with said hollow piston assembly and said second end being engageable with to at least one linkage member of said brake system such that movement of said piston rod assembly in an outward direction during a brake application initiates a braking sequence of said brake system;

(f) a first fluid communication means in fluid communication with said first space and said first outlet port of said control valve means for supplying said first fluid pressure signal within said first space during said brake application of the railway vehicle braking system resulting in movement of said hollow piston assembly away from said small piston assembly and generation of said first predetermined braking force and for evacuating fluid pressure from said first space during a brake release of the railway vehicle braking system resulting in movement of said hollow piston assembly toward said small piston assembly;

(g) a second fluid communication means in fluid communication with said second space and said second outlet port of said control valve means for supplying said second fluid pressure signal to said second space during said brake application of the brake system resulting in a further movement of said hollow piston assembly away from said small piston assembly and generation of said second predetermined braking force and for evacuating fluid pressure from said second space during said brake release of said brake system; and

(h) means for venting said second space to atmosphere during application of said fluid pressure within said first space.

8. A load compensating brake system for a railway car, according to claim 1, wherein said at least one control signal is at least one fluid pressure signal and wherein said control means is a metering control valve having:

(a) a housing attached to the vertically stationary portion of the at least one of the pair of truck assemblies and having an inlet port connected to a source of fluid pressure, an outlet port, and an internal partition means being interposed said inlet port and said outlet port;

(b) an orifice having a predetermined size and disposed within said internal partition means, whereby a flow of said fluid pressure from said inlet port to said outlet port passes through said orifice;

(c) a valve actuating means mounted for reciprocal motion within said housing and having a first end engageable with one of the vertically movable railway car structure and the vertically movable portion of the at least one of the pair of truck assemblies, said valve actuating means movable between a first position associated with the railway car carrying an empty load and a second position associated with the railway car carrying a full load;

(d) a seat means attached to a second end of valve actuating means and at least partially engageable with said orifice for changing said predetermined size thereof, whereby incremental movement of said valve actuating means between said first and said second position causes an incremental movement of said seat means and incremental change of said predetermined size of said orifice resulting in metering said fluid pressure received at said inlet port from said fluid pressure source and in generation of a predetermined fluid pressure signal at said outlet port which is proportional to the load carried by the railway car.

9. A load compensating brake system for a railway car, according to claim 8, wherein said actuating means includes a fluid communication means connected to said outlet port for receiving said predetermined fluid pressure signal during said brake application resulting in generation of a predetermined braking force.

10. A load compensating brake system for a railway car truck assembly, said brake assembly comprising:

(a) first and second brake beams interposed between a bolster member and a respective one of a wheel and axle set so as to be in substantially parallel relationship with the bolster member, said first and second brake beams having brake shoes carried thereon adjacent each wheel tread of the wheel and axle set for engagement therewith when said brake beams are spread apart;

(b) first and second transfer levers pivotally-connected, respectively, at a point intermediate each end thereof to said first and second brake beams, each said transfer lever forming first and second lever arms, an effective length of said first and second lever arms of at least one of said first and second transfer levers being dissimilar;

(c) first force-transmitting means passing through a first opening of the bolster member for connection with said first lever arms of said first and second transfer levers;

(e) second force-transmitting means passing through a second opening of the bolster member for connection with said second lever arms of said first and second transfer levers to effect rotation of said second transfer lever, whereby a force is exerted on said first and second brake beams, at said pivotal connection of said first and second transfer levers therewith, in opposite directions;

(f) a fluid pressure operated control valve means which is connected to a source of a fluid pressure at an inlet port thereof and which is attached to one of the railway car, at least one of a pair side frames and a combination thereof for sensing a vertical position of one of the bolster member, a vertically movable portion of a railway car structure and a combination thereof, said vertical position corresponding to a load carried by the railway car, said fluid pressure operated control valve means further generating a first fluid pressure control signal at a first outlet port when said vertical position defining an empty load carried by the railway car and generating a combination of said first fluid pressure control signal at said first outlet port and a second fluid pressure control signal at a second outlet port when said vertical position defining a load greater than said empty load carried by the railway car, said first and said second outlet ports being in fluid communication with said inlet port; and

(g) an actuating means disposed within said first force-transmitting means for effecting rotation of said first transfer lever, said actuating means engageable with a predetermined portion of said control means and selectively responsive to said first control signal to generate a first braking force and to combination of said first and said second control signals to generate a second braking force.

11. In a railway car mounted brake assembly having a brake actuator, a slack adjuster and a pair of brake beams mounted on each truck assembly of said railway car, said brake beams being actuated by said brake actuator via a series of levers and linkages, each of said brake beams having a brake head at each end thereof, each of said brake heads carrying a brake shoe thereon positioned for engagement with a respective one a respective railway vehicle wheel during a brake application, the improvement comprising:

(a) a fluid pressure operated control valve means which is connected to a source of a fluid pressure at an inlet port thereof and which is attached to one of said railway car, at least one of said truck assemblies and a combination thereof for sensing a vertical position of one of such vertically movable portion of at least one of said truck assemblies, a vertically movable portion of said railway car structure and a combination thereof, said vertical position defining a load carried by said railway car, said control means further generating a first fluid pressure control signal at a first outlet port when said vertical position defining an empty load carried by said railway car and generating a combination of said first fluid pressure control signal at said first outlet port and a second fluid pressure control signal at a second outlet port when said vertical position defining a load greater than said empty load carried by said railway car, said first and said second outlet ports being in fluid communication with said inlet port; and

(b) said brake actuator responsive to said first fluid pressure control signal to generate a first braking force associated with said empty load and to said combination of said first and said second fluid pressure control signals to generate a second braking force associated with said load greater than said empty load carried by said railway car and respectively apply one of said first braking force and said second braking force to each wheel of at least one of said truck assemblies.