Local derailment sensor and brake actuator system

Claim 2

A motion and temperature sensor system for detecting train wheel local derailment and actuating the brake system comprising: a motion sensor activated by wheel impact with the roadbed; a thermal sensor responsive to journal bearing temperature exceeding a predetermined value; an output signal generator operatively coupled with and activated by said motion sensor and said thermal sensor; and an electroexplosive means coupled to said signal generator for venting the brake system, whereby the train brake system is applied to stop the train upon detection of wheel impact with the roadbed or journal bearing temperature exceeding a predetermined value.

Claim 3

The sensor system of claim 1 further comprising an impact member and a biasing spring, said impact member being released by said motion sensor and said thermal sensor to activate said signal generator.

Claim 4

The sensor system of claim 2 wherein said thermal sensor comprises a heat responsive element which physically deforms at temperatures above a predetermined value.

Claim 5

The sensor system of claim 3 wherein said heat-responsive element comprises an intermetallic alloy of nickel and titanium.

Claim 6

The sensor system of claim 4 wherein said heat-responsive element comprises an elongated member extending adjacent said impact member to restrain said impact member against said biasing spring.

Claim 7

The sensor system of claim 5 wherein said motion sensor comprises: a displaceable mass; and a spring for maintaining said displaceable mass in a first position, said displaceable mass being moveable from said first position for wheel motions above a predetermined acceleration threshold and velocity change.

Claim 8

The sensor system of claim 6 wherein said displaceable mass is provided with an opening, said elongated heat-responsive member extends through said opening, and said spring maintains said displaceable mass in said first position and said heat-respOnsive member against said impact member.

Claim 9

The sensor system of claim 7 wherein said electroexplosive means comprises an explosively-actuated diaphragm cutter to puncture and vent the train brake line.

Claim 10

The sensor system of claim 8 wherein said diaphragm cutter is actuated by an explosively-extended bellows motor.

Claim 11

The sensor system of claim 9 further comprising a calibrated venting means connected to said diaphragm cutter capable of producing an audible signal upon brake line venting.

Claim 12

The sensor system of claim 8 wherein said output signal generator comprises a thermal battery activated by said impact member.

Claim 13

The sensor system of claim 11 wherein said thermal battery comprises: a pyrotechnic reactant; an electrochemical reactant; and a percussion primer triggered by said impact member to initiate an electric current producing reaction between said pyrotechnic reactant and said electrochemical reactant.

Claim 14

The sensor system of claim 8 wherein said output signal generator comprises a piezoelectric element initiated by said impact member.

Claim 15

The sensor system of claim 13 wherein said piezoelectric element comprises a detonator initiated by said impact member and piezoelectric crystals crushed by pressure from said detonator to produce an electric current.

Claim 16

The sensor system of claim 8 further comprising releasable restraining means for maintaining said displaceable mass in said first position.

Claim 17

The sensor system of claim 15 wherein said releasable restraining means comprises a ball release whereby a plurality of balls are movable between a restraining position and a release position.

Claim 18

The sensor system of claim 16 where said ball release comprises: a first cylindrical sleeve; a plurality of apertures provided in said first sleeve; a plurality of balls positioned in said apertures and contacting said displaceable mass; a concentric, inner cylindrical sleeve in contact with said plurality of balls and supporting said spring to exert an outward force on said balls; and a receiving recess in said displaceable mass located adjacent said plurality of balls, whereby said displaceable mass is maintained in said first position by the force of said plurality of balls, and upon acceleration of said displaceable mass by wheel impact with the roadbed, said mass is displaced downwardly to align said receiving recess with said balls, releasing said balls from the restraining position and permitting said heat-responsive member to release said impact member.

Claim 19

The sensor system of claim 17 wherein said output signal generator comprises a thermal battery activated by said impact member.

Claim 20

The sensor system of claim 18 wherein said thermal battery comprises a pyrotechnic reactant; an electrochemical reactants; and a percussion primer triggered by said impact member to initiate an electric current producing reaction between said pyrotechnic reactant and said electrochemical reactant.

Claim 21

The sensor system of claim 17 wherein said output signal generator comprises a piezoelectric element initiated by said impact member.

Claim 22

The sensor system of claim 20 wherein said piezoelectric element comprises a detonator initiated by said impact member and piezoelectric crystals crushed by pressure from said detonator to produce an electric current.