Temperature sensing brake lining wear indicator
First Claim
1. A method for indicating the amount of brake lining material in a drum brake assembly comprising the steps of:
- 1) providing a cylindrical drum, at least one arcuate brake shoe assembly having a brake lining supported by a backing plate and presenting a wear surface, said lining including first and second temperature sensors, and an actuator;
2) actuating the brake shoe assembly against the drum;
3) producing a first time signal T1 in response to timing the period for a first temperature sensor to reach a first predetermined temperature;
4) producing a second time signal T2 in response to timing the period for a second temperature sensor to reach a second predetermined temperature; and
5) activating a warning device indicating a worn brake lining when the ratio of the first time signal T1 to the second time signal T2 exceeds a predetermined limit.
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Accused Products
Abstract
A brake lining wear indicator utilizes a temperature sensor assembly embedded in a brake lining of a drum brake assembly. The temperature sensor assembly includes two temperature sensors with a first temperature sensor located at a first distance X from the wear surface of the brake lining and a second temperature sensor located at a second distance X+d from the wear surface. A timing device measures the time period for the first temperature sensor to reach a first predetermined temperature and measures the time period for the second temperature sensor to reach a second predetermined temperature. The remaining useful thickness of the brake lining is determined based on the ratio of the respective time periods. Thus, the indicator provides a time-temperature based determination of when the brake linings should be replaced. This determination is easily monitored during the operation of the vehicle and can be made without requiring a physical measurement or visual inspection of the thickness of the brake lining on each brake shoe.
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Citations
22 Claims
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1. A method for indicating the amount of brake lining material in a drum brake assembly comprising the steps of:
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1) providing a cylindrical drum, at least one arcuate brake shoe assembly having a brake lining supported by a backing plate and presenting a wear surface, said lining including first and second temperature sensors, and an actuator; 2) actuating the brake shoe assembly against the drum; 3) producing a first time signal T1 in response to timing the period for a first temperature sensor to reach a first predetermined temperature; 4) producing a second time signal T2 in response to timing the period for a second temperature sensor to reach a second predetermined temperature; and 5) activating a warning device indicating a worn brake lining when the ratio of the first time signal T1 to the second time signal T2 exceeds a predetermined limit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for indicating the amount of brake lining material in a brake assembly comprising:
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a first rotating member to be braked and disposed about an axis of rotation; at least one second member having a brake lining supported by a backing plate and presenting a wear surface opposite from said first member; an actuator for actuating said wear surface against said first member; a first sensor at a first distance in said brake lining; a second sensor at a second distance in said brake lining; a timing device for producing a first time signal T1 in response to timing the period for said first sensor to reach a first predetermined temperature and for producing a second time signal T2 in response to timing the period for said second sensor to reach a second predetermined temperature; and a processor for comparing said first time signal T1 to said second time signal T2 and for activating a warning device, indicating a worn brake lining, when the ratio of said first time signal T1 to said second time signal T2 exceeds a predetermined limit. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A brake assembly comprising:
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a brake lining supported by a backing plate and presenting a wear surface; a first sensor for measuring a first brake lining temperature;
second sensor for measuring a second brake lining temperature, said first and second sensors being embedded in said brake lining at different distances respectively from said wear surface; and
a processor for determining brake lining thickness based on a comparison of the first brake lining temperature to the second brake lining temperature. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A brake assembly comprising:
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a brake lining supported by a backing plate and presenting a wear surface; a first sensor for measuring a first brake lining temperature; a second sensor for measuring a second brake lining temperature, said first and second sensors being embedded in said brake lining at different distances respectively from said wear surface; a processor for determining brake lining thickness based on a comparison of the first brake lining temperature to the second brake lining temperature; and a timing device for producing a first time signal T1 in response to timing the period for said first sensor to reach a first predetermined temperature and for producing a second time signal T2 in response to timing the period for said second sensor to reach a second predetermined temperature. - View Dependent Claims (22)
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Specification