Thermostat with overlaod indicator

Claim 2

A thermostat, comprising a housing, a pair of spaced terminals secured to said housing and extending exteriorly thereof for connection in an electrical circuit, an electrically conductive switch arm secured to one of said terminals in electrical contact therewith, and having a free end extending into a chamber in said housing for movement in said chamber between a closed position, in which it is engaged with the other of said terminals electrically to connect said terminals to each other, and an open position, in which it is disengaged from said other terminal, means including a temperature-responsive element in said housing responsive to predetermined changes in the ambient temperature to cause said free end of said arm to be shifted from one to the other of said open and closed positions, respectively, a movable indicator element mounted in said housing to project at its inner end into said chamber, and being movable from a retracted position in which said indicator element is disposed substantially within said housing, to an extended position in which a portion of the outer end of said indicator element projects exteriorly of said housing, when said free end of said arm is moved to said other position, a resilient, snap acting spring, means mounting said spring in said chamber to extend between said arm and said inner end of said indicator, but to be spaced from said arm when said arm is closed so that no current will then flow through said spring, and said spring being operative resiliently to resist initial movement of said indicator element by said arm from one to the other of its two limit positions.

Claim 3

A thermostat, comprising a housing, a pair of spaced terminals secured to said housing and extending exteriorly thereof for connection in an electrical circuit, an electrically conductive switch arm secured to one of said terminals in electrical contact therewith, and having a free end extending into a chamber in said housing for movement in said chamber between a closed position, in which it is engaged with the other of said terminals electrically to connect said terminals to each other, and an open position, in which it is disengaged from said other terminal, means including a temperature-responsive element in said housing responsive to predetermined changes in the ambient temperature to cause said free end of said arm to be shifted from one to the other of said open and closed positions, respectively, a movable indicator element mounted in said housing to project at its inner end into said chamber, and being movable from a retracted position in which said indicator element is disposed substantially within said housing, to an extended position in which a portion of the outer end of said indicator element projects exteriorly of said housing, when said free end of said arm is moved to said other position, a resilient, snap acting spring, means mounting said spring in said chamber to extend between said arm and said inner end of said indicator, but to be spaced from said arm when said arm is closed so that no current will then flow through said spring, and said spring being operative resiliently to resist initial movement of said indicator element by said arm from one to the other of its two limit positions.

Claim 4

A thermostat, comprising a housing, a pair of spaced terminals secured to said housing and extending exteriorly thereof for connection in an electrical circuit, an electrically conductive switch arm secured to one of said terminals in electrical contact therewith, and having a free end extending into a chamber in said housing for movement in said chamber between a closed position, in which it is engaged with the other of said terminals electrically to connect said terminals to each other, and an open position, in which it is disengaged from said other terminal, means including a temperature-responsive element in said housing responsive to predetermined changes in the ambient temperature to cause said free end of said arm to be shifted from one to the other of said open and closed positions, respectively, a movable indicator element mounted in said housing to project at its inner end into said chamber, and being movable from a retracted position in which said indicator element is disposed substantially within said housing, to an extended position in which a portion of the outer end of said indicator element projects exteriorly of said housing, when said free end of said arm is moved to said other position, a resilient, snap acting spring, means mounting said spring in said chamber to extend between said arm and said inner end of said indicator, but to be spaced from said arm when said arm is closed so that no current will then flow through said spring, and said spring being operative resiliently to resist initial movement of said indicator element by said arm from one to the other of its two limit positions.

Claim 5

A thermostat comprising a housing, a pair of spaced terminals secured to said housing and extending exteriorly thereof for connection in an electrical circuit, an electrically conductive switch arm secured to one of said terminals in electrical contact therewith, and having a free end extending into said housing for movement between a closed position, in which it is engaged with the other of said terminals electrically to connect said terminals to each other, and an open position, in which it is disengaged from said other terminal, a temperature-responsive element in said housing responsive to predetermined changes in the ambient temperature to cause said free end of said arm to be shifted from one to the other of said open and closed positions, respectively, a movable indicator element mounted in said housing for movement from a retracted position in which said indicator element is disposed substantially within said housing, to an extended position in which a portion of said indicator element projects exteriorly of said housing, when said free end of said arm is moved to said other position, and resilient means interposed between said elements and operative resiliently to resist initial movement of said indicator element from one to the other of its two limit positions, and vice versa, said indicator element being reciprocable in a bore in said housing, said housing having therein a pair of spaced recesses opening on said bore adjacent opposite ends thereof, and a resilient spring member secured to said element for sliding movement thereby in said bore between a first position in which said member is engaged in one of said recesses to resist movement of said element to its extended position, and a second position in which said member is engaged in the other of said recesses releasably to secure said element in its extended position.

Claim 6

A thermostat comprising a housing, a pair of spaced terminals secured to said housing and extending exteriorly thereof for connection in an electrical circuit, an electrically conductive switch arm secured to one of said terminals in electrical contact therewith, and having a free end extending into said housing for movement between a closed position, in which it is engaged with the other of said terminals electrically to connect said terminals to each other, and an open position, in which it is disengaged from said other terminal, a temperature-responsive element in said housing responsive to predetermined changes in the ambient temperature to cause said free end of said arm to be shifted from one to the other of said open and closed positions, respectively, a movable indicator element mounted in said housing for movement from a retracted position in which said indicator element is disposed substantially within said housing, to an extended position in which a portion of said indicator element projects exteriorly of said housing, when said free end of said arm is moved to said other position, and resilient means interposed between said elements and operative resiliently to resist initial movement of said indicator element from one to the other of its two limit positions, and vice versa, said indicator element being reciprocable in a bore in said housing, said housing having therein a pair of spaced recesses opening on said bore adjacent opposite ends thereof, and a resilient spring member secured to said element for sliding movement thereby in said bore between a first position in which said member is engaged in one of said recesses to resist movement of said element to its extended position, and a second position in which said member is engaged in the other of said recesses releasably to secure said element in its extended position.

Claim 7

A thermostat as defined in claim 2, wherein said element comprises a pin reciprocable in said bore, said spring member is secured at one end to said pin and has a lip on its opposite end urged resiliently away from said pin into sliding engagement with the wall of said bore selectively to seat in said recesses, said one recess is a camming surface on said housing at the inner end of said bore and inclined to the axis of said bore, and said other recess is a transverse notch formed in said housing at the outer end of said bore.

Claim 8

A thermostat as defined in claim 1, wherein said snap-acting spring is operative to move said indicator element into its extended position, when the free end of said arm moves to its open position, and resiliently retains said indicator element in its extended position independently of the subsequent movement of said free end of said switch arm to closed position, said indicator element being returnable manually to its retracted position.

Claim 9

A thermostat as defined in claim 1, wherein said indicator element is a pin mounted to reciprocate in an opening in one end of said housing, means on said housing is engaged With opposite ends, respectively, of said spring to support the mid-portion of said spring for snap-acting movement in opposite directions axially of said pin, and means is provided for securing said pin to said mid-portion of said spring resiliently to be held thereby in said retracted and extended positions, respectively.

Claim 10

A thermostat as defined in claim 1, wherein said indicator element is a pin mounted to reciprocate in an opening in one end of said housing, means is provided for securing one end of said spring in said housing adjacent one side of said chamber, said spring having a free, cantilevered end extending into said chamber between said free end of said switch arm and said pin to transmit the movement of said free end of said arm to said pin upon movement of said free end of said arm to its open position.

Claim 11

A thermostat as defined in claim 1, wherein said indicator element comprises a pin mounted to reciprocate in an opening in one end of said housing, said temperature-responsive element comprises a bimetallic disc mounted in said chamber between said pin and said arm and being normally bowed inwardly toward said arm to hold the arm in closed position, and disposed to flex in opposite directions axially of said pin in response to predetermined changes in said ambient temperature, a flexible layer of dielectric material is interposed between said disc and said arm to allow movement of said free end of said arm to its open position, when said central portion of said disc is flexed in one direction, and said spring is interposed between said disc and said pin and is responsive to the flexing of said disc in said one direction to shift said pin suddenly from its retracted to its extended position.