Railroad car with brake system which applies less braking when empty than when loaded

• US 4,826,259 A
• Filed: 05/20/1988
• Issued: 05/02/1989
• Est. Priority Date: 11/06/1985
• Status: Expired due to Fees

• Current Assignee: Thrall Car Manufacturing Co. (Trinity Industries Incorporated)
• Original Assignee: Thrall Car Manufacturing Co. (Trinity Industries Incorporated)
• Inventors: Biegel, Robert A.
• Primary Examiner(s): Reger, Duane A.
• Application Number:
  US07/196,446
• Time in Patent Office: 347 Days
• Field of Search: 303/22.2, 303/22.6, 303/56
• US Class Current: 303/22.2
• CPC Class Codes: B60T 8/1893 especially adapted for railway vehicles
• CPC Class Codes: B61F 5/24 Means for damping or minimising the canting, skewing, pitching, or plunging movements of the underframes
• CPC Class Codes: B61H 13/20 Transmitting mechanisms wear-compensating mechanisms B61H15/00

Abstract

A railroad freight car comprising a freight-carrying first elongated body supported at one end by a first truck and at the other end by a second truck; each truck having a plurality of wheels and carrying air pressure operated braking apparatus for braking the wheels; the air pressure operated braking apparatus on the first truck including a pressurized air line having an air pressure sensor/changeover valve which governs the braking pressure applied only to the wheels of the first truck; the first truck having a bolster, spring-supported at each end by wheel-containing side frames, whereby the bolster is lowered relative to the frame when the elongated body condition varies from empty to loaded; a base mounting the air pressure sensor/changeover valve to the bolster; and, the valve having an arm responsive to change in height of the bolster relative to the frame to decrease the air pressure to the brake apparatus from a high pressure, when the elongated body is loaded, to a lower pressure when the elongated body has an empty load condition to thereby apply a predetermined high braking force to the wheels when the elongated body is loaded and apply a decreased or lower braking force to the wheels when an empty condition exists.

Claims

1. A railroad freight car comprising:

a freight carrying first elongated body supported at one end by a first truck and at the other end by a second truck;

each truck having a plurality of wheels and carrying air pressure operated braking apparatus for braking the wheels;

the air pressure operated braking apparatus on the first truck including a pressurized air line having an air pressure sensor/changeover valve, having an air volume means in which to store air when the car is empty to thereby decrease the braking pressure, directly through which pressurized air, supplied from conventional braking equipment required on freight cars by existing regulations and including an air control valve and auxiliary and emergency reservoirs, flows and which governs the braking pressure applied to the wheels of the first truck;

the first truck having a bolster, spring supported at each end by wheel-containing side frames, whereby the bolster is lowered relative to the frame when the elongated body condition varies from empty to loaded;

means mounting the air pressure sensor/changeover valve to the bolster; and

the valve having means responsive to change in height of the bolster relative to the frame to directly decrease the air pressure of air supplied by the air line through the valve directly to the brake apparatus from a high pressure when the elongated body is loaded to a low pressure, which is a predetermined fraction of the high pressure, when an empty condition exists to thereby apply a predetermined braking force to the wheels when the elongated body is loaded and apply a decreased braking force to the wheels with an empty condition.

2. A railroad car according to claim 1 in which:

the air pressure operated braking apparatus on the second truck includes an air line having an air pressure sensor/changeover valve, having an air volume means in which to store air when the car is empty to thereby decrease the braking pressure, directly through which pressurized air, supplied from conventional braking equipment required on freight cars by existing regulations and including an air control valve and auxiliary and emergency reservoirs flows and which governs the braking pressure applied to the wheels of the second truck;

the second truck having a bolster, spring supported at each end by wheel-containing side frames, whereby the bolster is lowered relative to the frame when the elongated body condition varies from empty to loaded;

means mounting the air pressure sensor/changeover valve to the bolster; and

the valve having means responsive to change in height of the bolster relative to the frame to directly increase the air pressure of air supplied by the air line through the valve directly to the brake apparatus from a low pressure when the elongated body is empty, to a high pressure when a maximum load is carried by the elongated body, to thereby apply a predetermined lower braking force to the wheels when the elongated body is empty and apply an increased braking force to the wheels at maximum load, said low pressure being a predetermined fraction of the high pressure.

3. A railroad car according to claim 1 in which each truck is a four wheel truck.

4. A railroad car according to claim 2 in which each truck has two axles supported by the side frames, and each axle has two wheels.

5. A railroad car according to claim 1 in which the first truck supports one end of the first elongated body, and one end of a second elongated body, through an articulated connector supported on the first truck bolster.

6. A railroad car according to claim 2 in which:

the first truck supports one end of the first elongated body, and one end of a second elongated body, through an articulated connector supported on the first truck bolster; and

the second truck supports the second end of the second elongated body, and one end of a third elongated body, through an articulated connector supported on the second truck bolster.

7. A railroad car according to claim 5 in which a side bearing support is positioned on each side of the bolster center adjacent the truck frames and the valve is mounted on one of the side bearing supports.

8. A railroad car according to claim 7 in which the valve means responsive to change in height of the bolster relative to the side frame is an arm extending from the valve into contact with the frame.

9. A railroad car truck comprising:

a truck bolster supported at each end by springs mounted in two opposing rigid side frames in which at least one axle containing two wheels is mounted;

the bolster being displaceable relative to the frames from maximum height when a tare weight load is applied to the bolster to a minimum height when a maximum lading load is applied to the bolster;

the truck carrying air pressure operated braking apparatus for braking the wheels;

the air pressure operated braking apparatus including a line for pressurized air, the line having an air pressure sensor/changeover valve, having an air volume means in which to store air when the car is empty to thereby decrease the air braking pressure, directly through which pressurized air, supplied from conventional braking equipment required on freight cars by existing regulations and including an air control valve and auxiliary and emergency reservoirs, flow and which governs the braking pressure applied to the wheels of the truck;

means mounting the air pressure sensor/changeover valve to the bolster; and

the valve having means responsive to change in height of the bolster relative to the frame to directly decrease the air pressure of air supplied by the air line through the valve directly to the brake apparatus from a high pressure, which applies maximum braking force when a loaded condition is applied to the bolster, to a lower pressure, which is a predetermined fraction of the high pressure, when an empty condition is applied to the bolster, to thereby apply a predetermined lower braking force to the wheels when an empty condition is applied to the bolster and to apply an increased braking force to the wheels when a loaded condition exists.

10. A railroad car truck according to claim 9 in which a pair of axles containing two wheels each is mounted in the side frames.