Device for monitoring the flow in the air line of an air brake system on a railway vehicle

• US 3,957,314 A
• Filed: 11/25/1974
• Issued: 05/18/1976
• Est. Priority Date: 11/24/1973
• Status: Expired due to Term

• Current Assignee: Knorr-Bremse AG (Estate of Heinz Hermann Thiele)
• Original Assignee: Knorr-Bremse GmbH
• Inventors: Falke, Erich
• Primary Examiner(s): Blix, Trygve M.
• Assistant Examiner(s): Butler, Douglas C.
• Application Number:
  US05/526,738
• Time in Patent Office: 540 Days
• Field of Search: 303/1-3, 303/59-60, 303/66-67, 303/69, 303/84, 303/81, 303/86, 116/55, 116/70
• US Class Current: 303/3
• CPC Class Codes: B60T 17/228 for railway vehicles

Abstract

The pressure in an air line in an air braking system for a railway vehicle is controlled by an operator'"'"'s brake valve which is also constructed to maintain the pressure therein. A pressure monitor is responsive to the pressure drop across a restrictor in the air line or in a supply line leading from a source of compressed air. A control line is connected to an energy source through a shut-off device operable by the pressure monitor and through a two-position switch to be connected to a monitor device for brake release operation or to a second monitor device for the flow of air in the air line caused by defects or application of the emergency brake. The shut-off switch will move to the energy passing position only when a certain pressure difference in the restrictor is excceded. The two-position switch is actuated by the operator'"'"'s brake valve and connects the brake release monitor device to the control line only when the operator'"'"'s brake valve is in its brake release position. Otherwise, the two-position switch connects the control line to the monitor device for defect-originated air flow.

Claims

1. In a device for monitoring the flow in an air line of an air brake system on a railway vehicle, th combination of an air line connected to a source of compressed air and an operator'"'"'s brake valve therein to control pressure in said air line and movable between brake release and brake applied positions, a restrictor in said air line, pressure sensing means responsive to a pressure drop in said restrictor, a first control line including a first switching means responsive to said pressure sensing means and connected to a source of energy for passing energy therethrough only when a predetermined pressure difference across said restrictor is exceeded, second switching means connected to said first switching means and having a first normally closed position and a second normally open position, means connected to said first position of said second switching means for indicating a brake release, means responsive to an increase in pressure at said operator'"'"'s brake valve for connecting said second switching means through said first switching means to said source of energy whereby said brake release indicating means is energized only when said operator'"'"'s brake valve is in the brake release position, and means connected to said normally closed first position of said second switching means for indicating a defect-originated flow of air in the air line when a predetermined pressure drop occurs across said restrictor.

2. In a device as claimed in claim 1 and a third switching means in a second control line connected between said energy source and said brake release indicating means, means for actuating said third switching means into the energy passing condition only when said operator'"'"'s brake valve is in the brake release position, said second switching means including a relay energized in response to the passage of energy in said second control line.

3. In a device as claimed in claim 2 and a servo control circuit having a selective operating pressure level connected to said operator'"'"'s brake valve, a relay valve in said air line and responsive to the pressure in said servo control circuit to control the pressure in said air line, a piston actuated by the pressure in said servo control line to actuate said third switch means, said piston having a throttle opening therein to throttle pressure in the direction to open said third switch means and the pressure acting unthrottled in the direction to close said third switch means.

4. In a device as claimed in claim 2 and a shut-off valve in said air line and closed when said defect-originated indicating means is energized, a third control line from said source of energy to said defect-originated indicating means, fourth switch means in said third control line operable to a position to block the passage of energy in said third control line only when said operator'"'"'s brake valve is in a braking position, and fifth switch means in said third control line operable to a position to pass energy therethrough only when said defect-originated indicating means is energized.

5. In a device as claimed in claim 4 wherein said fourth switch means is switched by said piston to an energy blocking position when said piston is subjected to an unthrottled pressure through said servo control circuit.

6. In a device as claimed in claim 5 and a first spring means constantly acting on said third switch means for loading thereof into the energy blocking position, and second spring means constantly acting on said fourth switch means for loading thereof into the energy passing position.

7. In a device as claimed in claim 4 wherein said fifth switch means is connected to said brake release indicating means for limiting the driving power of a driving railway vehicle to a low value when energized.

8. In a device as claimed in claim 4 wherein said energy source comprises a source of electrical energy, said first, third and fourth switch means each comprises electric pressure-differential switches, said second and fifth switch means each comprises electric relay switches, said shut-off valve comprises a solenoid valve.

9. In a device as claimed in claim 1 wherein said brake release and defect-originated indicating means each comprise an optical indicator.

10. In a device as claimed in claim 1 wherein said energy source comprises a fluid pressure source.