Thermally sensitive circuit control apparatus

Claim 2

Apparatus for controlling an electric circuit comprising electrically conductive, homogeneous control means forming part of said circuit and being adjustable between circuit opening and circuit closing conditions, said control means having an initial, thermally unstable, configuration at a temperature below a predetermined temperature such as to establish one of said circuit conditions and being responsive to reaching said predetermined temperature to change forcibly to a second, thermally stable configuration such as to establish the other of said circuit conditions; resilient holding means acting on said control means and yiEldably maintaining the latter in said initial configuration, said control means being operable to overcome said holding means and change from its initial configuration to said second configuration in response to the temperature of said control means reaching said predetermined temperature, said holding means being operable to return said control means to said initial configuration in response to a reduction in the temperature thereof to one below said predetermined temperature; and means for raising the temperature of said control means to said predetermined temperature.

Claim 3

Apparatus as set forth in claim 1 wherein said control means comprises a member composed of nickel-titanium alloy.

Claim 4

Apparatus as set forth in claim 2 wherein said alloy is nickel rich.

Claim 5

Apparatus as set forth in claim 1 wherein the said control means is substantially immune to changes in temperature below said predetermined temperature.

Claim 6

Apparatus as set forth in claim 1 wherein said holding means is operable to restore said control means to said initial configuration automatically following reduction of its temperature below said predetermined temperature.

Claim 7

Apparatus as set forth in claim 1 including a contact carried by said control means.

Claim 8

Apparatus for controlling an electric circuit comprising fixed contact means; first and second movable contact means; first and second carrier means straddling said fixed contact means and respectively supporting said first and second contact means on opposite sides of said fixed contact means; means coupling said carrier means to each other for conjoint movement and maintaining said first and second contact means in spaced relation such that one only of said movable contact means may engage said fixed contact means at any one time, each of said carrier means being shaped to an initial, thermally unstable configuration at a temperature below a predetermined temperature and being formed of material which when heated to said predetermined temperature changes configuration in such manner as to move one of said movable contact means toward said fixed contact means; and means for alternately heating said first and second carrier means to said predetermined temperature.

Claim 9

Apparatus for controlling an electric circuit comprising fixed contact means; first and second movable contact means; first and second carrier means straddling said fixed contact means and respectively supporting said first and second contact means on opposite sides of said fixed contact means; means coupling said carrier means to each other for conjoint movement and maintaining said first and second contact means in spaced relation such that one only of said movable contact means may engage said fixed contact means at any one time, each of said carrier means being shaped to an initial, thermally unstable configuration at a temperature below a predetermined temperature and being formed of material which when heated to said predetermined temperature changes configuration in such manner as to move one of said movable contact means toward said fixed contact means; and means for alternately heating said first and second carrier means to said predetermined temperature.

Claim 10

Apparatus as set forth in claim 7 wherein the material from which each of said carrier means is formed is homogeneous.

Claim 11

Apparatus as set forth in claim 8 wherein said material is a nickel-titanium alloy.

Claim 12

Apparatus as set forth in claim 7 wherein said carrier means are formed of electrically conductive material and form part of said circuit.

Claim 13

Apparatus for controlling an electric circuit comprising fixed contact means; first and second movable contact means; first and second carrier means respectively supporting said first and second movable contact means, each of said carrier means having a thermally stable configuration at a predetermined, critical temperature but being reshaped below said critical temperature in such direction as to assume a first thermally unstable configuration and being formed of material which when heated to said critical temperature tends to return to said thermally stable configuration; means mounting said first and second carrier means in positions such that either of said movable contact means may engage said fixed contact means but in which one only of said movable contact means initially engages said fixed contact means; means for heating said one of said carrier means to said critical temperature whereby said one of said carrier means changes its configuration and moves in a direction to effect disengagement of said one of said movable contact means and said fixed contact means; and means coupling said first and second carrier means for conjoint movement thereof, said mounting means mounting the other of said carrier means in such position that said change of configuration of said one of said carrier means effects movement of said other of said carrier means and a change in the configuration thereof to a second, thermally unsTable configuration.

Claim 14

Apparatus for controlling an electric circuit comprising fixed contact means; first and second movable contact means; first and second carrier means respectively supporting said first and second movable contact means, each of said carrier means having a thermally stable configuration at a predetermined, critical temperature but being reshaped below said critical temperature in such direction as to assume a first thermally unstable configuration and being formed of material which when heated to said critical temperature tends to return to said thermally stable configuration; means mounting said first and second carrier means in positions such that either of said movable contact means may engage said fixed contact means but in which one only of said movable contact means initially engages said fixed contact means; means for heating said one of said carrier means to said critical temperature whereby said one of said carrier means changes its configuration and moves in a direction to effect disengagement of said one of said movable contact means and said fixed contact means; and means coupling said first and second carrier means for conjoint movement thereof, said mounting means mounting the other of said carrier means in such position that said change of configuration of said one of said carrier means effects movement of said other of said carrier means and a change in the configuration thereof to a second, thermally unsTable configuration.

Claim 15

Apparatus according to claim 11 wherein the movement of said other of said carrier means in response to said change of configuration of said one of said carrier means is in the same direction that said other of said carrier means was reshaped.

Claim 16

Apparatus according to claim 12 wherein the movement of said other of said carrier means effects engagement between the movable contact supported by said other of said carrier means and said fixed contact.

Claim 17

Apparatus according to claim 11 wherein said thermally stable configuration of each of said carrier means is arcuate and wherein the reshaped configuration of each of said carrier means also is arcuate.

Claim 18

Apparatus according to claim 14 wherein the stable and reshaped arcuate configurations are of different radii.

Claim 19

Apparatus according to claim 15 wherein the reshaped configuration has a smaller radius than that of the stable configuration.

Claim 20

Apparatus according to claim 11 wherein said movable contact means straddle said fixed contact means.