Short travel detector for empty/load brake control

• US 6,305,756 B1
• Filed: 08/04/2000
• Issued: 10/23/2001
• Est. Priority Date: 08/04/2000
• Status: Expired due to Term

• Current Assignee: Westinghouse Air Brake Technologies Corporation
• Original Assignee: Westinghouse Air Brake Technologies Corporation
• Inventors: Krampitz, Mark S., Scott, Daniel G.
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US09/635,038
• Time in Patent Office: 445 Days
• Field of Search: 303/22.2, 303/22.3, 303/22.8, 303/22.7, 303/22.6, 188/195, 731/46
• US Class Current: 303/22.2
• CPC Class Codes: B60T 8/1837 characterised by the load-detecting arrangements
• CPC Class Codes: B60T 8/1893 especially adapted for railway vehicles

Abstract

An empty/load brake control system mountable on a sprung and an unsprung member of a railway car and disposed between the car brake control valve and brake cylinder for adjusting the brake cylinder pressure during a brake application according to the car load condition. Such system includes an empty/load sensor valve device and a sensor arm coupled to a sensor cable whose movement is controlled by a sprung member and a terminal member disposed on an end of sensor cable, in contact with sprung member so that any downward movement of sprung member forces such terminal member in a similar downward direction and similarly pulls on the sensor cable. A piston, under pressure, urges the sensor arm to rotate and retract sensor cable but must overcome resistance of a spring. The system includes a load proportional valve.

Claims

1. An empty/load brake control system having at least a first portion mountable on a sprung member and a second portion on an unsprung member of a railway car and operably disposed between a railway car brake control valve device and a brake cylinder device for adjusting pressure being exerted on such brake cylinder during a brake application according to a loaded condition of such railway car, said empty/load brake control system comprising:

(a) an empty/load sensor valve device with an inlet passage connected to said brake control valve device and an outlet passage connected to said brake cylinder device;

(b) a load sensing means connected to said empty/load sensor valve and having a first portion disposed on such sprung member and a second portion disposed on such unsprung member for measuring a distance therebetween to provide an empty setting and a load setting of said empty/load sensor valve device depending upon said distance being one of greater and less than a predetermined distance corresponding to a changeover point between said empty and said load settings, said load sensing means including;

(i) a sensor arm pivotably connected to a portion of said empty/load sensor valve device and having a first end thereof connected to a sensor piston member disposed for reciprocal movement in said empty/load sensor valve device,

(ii) a terminal member disposed in contact with such sprung member so that any downward movement of such sprung member forces said terminal member in a similar downward direction,

(iii)a sensor cable connected on a first end thereof to a second end of said sensor arm and on a second end thereof to said terminal member, said sensor cable moving in a direction which urges said sensor arm away from a retracted position when said terminal member moves in a downward direction in response to downward movement of such sprung member, said sensor piston being subject to fluid under pressure effective at said inlet passage of said empty/load sensor valve device during such brake application for urging movement of said sensor arm to rotate and retract said sensor cable, and

(iv) a sensor spring caged in a cavity in said empty/load sensor valve device and disposed in contact with a wall of said empty/load sensor valve device and with said sensor piston for resisting movement of said sensor piston by a predetermined preload of said sensor spring;

(c) a load proportional valve means disposed between said empty/load sensor valve device and said brake control valve, having a proportioning mode of operation and a non-proportioning mode of operation, said load proportional valve means including;

(i) a fixed valve seat disposed between inlet and outlet passages of said load proportional valve,

(ii) a balance piston having equal opposing pressure areas, a first one of said opposing pressure areas being subject to fluid under pressure effective at said inlet passage, and

(iii) a release check valve including a valve member connected to said balance piston which engages said fixed valve seat; and

(d) an equalizing reservoir disposed between said load proportional valve means and said empty/load sensor valve device for providing necessary volume to maintain a satisfactory relationship for various pipe brake reductions, said empty/load sensor valve device is fluidly connected to said balance piston of said load proportional valve for supplying fluid under pressure effective at said inlet passage to a second one of said opposing pressure areas of said balance piston when said empty/load sensor valve device is in said empty setting to establish a differential force across said balance piston in a direction of engagement of said valve member of said check valve with said fixed valve seat, thereby providing said proportioning mode of operation and not supplying fluid under pressure to said second one of said opposing pressure areas of said balance piston when said empty/load sensor valve device is in said load setting thereby providing said non-proportioning mode of operation.

2. An empty/load brake control system, according to claim 1, wherein downward movement of such sprung truck member for a predetermined distance will cause full travel of said sensor arm.

3. An empty/load brake control system, according to claim 2, wherein said predetermined distance is one inch.

4. An empty/load brake control system, according to claim 1, wherein said pivotably connected sensor arm being pulled by said sensor cable when such sprung truck member moves in a downward direction provides a system in which less friction is produced.

5. An empty/load brake control system, according to claim 4, wherein a reduced diameter cable is used for said sensor cable since less friction is produced by said sensor cable and said sensor arm arrangement.

6. An empty/load brake control system, according to claim 1, wherein said terminal member further includes a tapered top portion.

7. An empty/load brake control system, according to claim 6, wherein said tapered top portion of said terminal member significantly reduces the possibility of any undesirable build up of snow and mud between said terminal member and such sprung truck member.