Gravity based brake stroke sensor methods and systems

• US 8,078,375 B2
• Filed: 07/07/2008
• Issued: 12/13/2011
• Est. Priority Date: 08/11/2004
• Status: Active Grant

• Current Assignee: Stemco Products, Inc. (Enpro Industries Incorporated)
• Original Assignee: Stemco LP (Enpro Industries Incorporated)
• Inventors: Steph, James C., Kranz, Mark J.
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Shafi, Muhammad
• Application Number:
  US12/168,795
• Publication Number:
  US 20080269983A1
• Time in Patent Office: 1,254 Days
• Field of Search: 701/29, 701 70- 71, 340/453, 188/1.11 E
• US Class Current: 701/70
• CPC Class Codes: B60T 17/08 Brake cylinders other than ultimate actuators with built-in wear-compensating mechanisms, ultimate actuators F16D
• CPC Class Codes: B60T 17/18 Safety devices; Monitoring

Abstract

Methods and systems for measuring a brake stroke of an air brake assembly utilize a sensor, such as an accelerometer, mountable on a movable component, such as a brake cam shaft, of the air brake assembly that is external of the brake chamber of the air brake assembly for detecting an acceleration of the movable component during a braking event. The sensor generates an output signal that depends on a magnitude of the detected acceleration, which is sent to a microcontroller coupled to the sensor. The microcontroller translates the sensor output signal to a value corresponding to a displacement of the movable component of the brake assembly during the braking event and calculates a brake stroke distance based on said value.

Claims

1. A method of measuring a brake stroke of an air brake assembly, comprising:

detecting an acceleration of a rotating shaft of the air brake assembly during a braking event by a sensor mounted on the rotating shaft external of a brake chamber of the air brake assembly, the sensor rotating with the rotating shaft;

generating an output signal by the sensor that depends on a magnitude of the detected acceleration;

translating the sensor output signal to a value corresponding to a displacement of the rotating shaft of the brake assembly during the braking event by a microcontroller coupled to the sensor; and

calculating a brake stroke distance based on said value from the microcontroller.

2. The method of claim 1, wherein detecting the acceleration by the sensor further detecting the acceleration by an accelerometer.

3. The method of claim 1, wherein detecting the acceleration further comprises detecting the acceleration of the rotating shaft along at least two different axes relative to the rotating shaft during the braking event.

4. The method of claim 1, wherein detecting the acceleration further comprises detecting the acceleration of the rotating shaft along at least two different axes relative to the rotating shaft during the braking event by a dual axis accelerometer.

5. The method of claim 1, wherein detecting the acceleration further comprises detecting the acceleration of the rotating shaft along at least two different axes relative to the rotating shaft during the braking event by at least two unidirectional accelerometers.

6. The method of claim 1, wherein generating the output signal further comprises generating a direct current voltage output signal by the sensor that varies in proportion to the magnitude of the detected acceleration.

7. The method of claim 1, wherein translating the sensor output signal to the value corresponding to a displacement of the rotating shaft further comprises translating the sensor output signal to angular values representing a rotary displacement of the rotating shaft during the braking event.