US 5,450,930 AGranted

Heavy duty electronic brake stroke indicator

AssigneeMGM Brakes

InventorsTimothy F. Martens, Robert J. Hicks, Robert J. Hilding

Life of this patent

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Abstract

Electronic stroke indicators have sensor structures which are incorporated into a stone shield for a brake actuator. The incorporation of the sensor into the stone shield protects the sensor and its associated wires and contacts from damage by the other components in the brake actuator. In particular, the spring is typically maintained out of contact with any of the electric portions of the electronic stroke indicator, thus prolonging the life of the electronic stroke indicator. In further features of this invention, a magnetic sensor may monitor the position of magnetic portions on a piston rod. Alternatively, a pair of electric contact switches may be serially contacted by a structure on the piston rod as the brake moves further out of stroke. The two electric contacts provided different signals to an operator in a vehicle cab such that signals of the level of out-of-stroke conditions are provided to the operator. In a further embodiment, a load cell monitors the compression in a spring in the brake housing to provide an indication of an out-of-stroke condition.

Claims9

Dependent claims

A brake actuator with a sensor system to sense exclusive required movement of a push rod to actuate an associate brake comprising:

a housing having a bore;
a piston received within said housing and having the piston rod extending through said bore, a magnetic stroke indicating member carried by said piston rod;
a stone shield having an inner bore surrounding said piston rod, said piston rod extending through said bore in said stone shield, said bore in said stone shield having a smaller inner diameter than said housing bore;
and said stone shield having an outer periphery and a sensor embedded in said stone shield between said outer periphery and said inner bore, said sensor monitoring the stroke of said piston rod by monitoring movement of said stroke indicating member on the piston rod, and said sensor being capable of sensing movement of said magnetic member on said piston rod, said sensor being embedded in said stone shield such that it is capable of monitoring movement of said magnetic member on said piston rod, the movement of said magnetic member on said piston rod being indicative of the movement of said piston, and hence undue movement of said piston being sensed by said sensor.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 08/164,396Filed 9 Dec 1993
Granted: 19 Sep 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

F16D 66/026
Using electrical detection or indication means: indicating different degrees of lining wear
F16D 66/025
Indicating that a lining is worn to minimum allowable thickness: sensing the position of parts of the brake system other than the braking members,…
F16D 66/028
Using electrical detection or indication means: with non-electrical sensors or signal transmission, e.g. magnetic, optical
F16D 2066/003
Arrangements for monitoring working conditions, e.g. wear, temperature: position, angle or speed