Electrical snap action switch apparatus

Claim 2

Electrical contact making and breaking apparatus comprising: means providing opposed, spaced apart, reaction surfaces at least one of which is electrically conductive; a thin, resilient element including a longitudinally extending blade having opposite longitudinal edges and an interior edge that is spaced from said reaction surfaces and from said longitudinal edges, an outer end portion of said blade being movable alternately into engagement with said surfaces; means stressing said blade to be positionally unstable in a central position thereof and to be biased toward a transversely curved configuration extending longitudinally at an angle on either side of said central position, said blade including an inner portion adjacent said interior edge, said outer end portion having an electrically conductive front face portion engaging an electrically conductive one of said reaction surfaces in one position of the blade and a back face engaging the opposite reacTion surface in another position of the blade; actuator means for moving said inner portion of said blade back and forth relative to said reaction surfaces, said actuator means cooperating with said blade to urge said outer end portion against the engaged reaction surface with increasing contact force upon movement of said actuator means in one direction and to progressively buckle successive transverse cross sections of said blade from adjacent said outer end portion toward said inner portion upon continued movement of said actuator means and thereby to increase contact force until said blade reaches its unstable central position and snaps so as to make and break electrical contact between said electrically conductive front face portion of said blade and an electrically conductive one of said reaction surfaces.

Claim 3

Electrical contact making and breaking apparatus according to claim 1, wherein said angle is at least 5* .

Claim 4

Electrical contact making and breaking apparatus according to claim 1, wherein said angle is at least 10* .

Claim 5

Electrical contact making and breaking apparatus according to claim 1 wherein movement of said actuator means in one direction causes said free outer end portion of said blade to snap in an opposite direction, whereby the initial motion of said actuator means in a contact breaking sequence serves to increase contact pressure.

Claim 6

Electrical contact making and breaking apparatus according to claim 4, wherein the extent of movement of said actuator means is so restricted relative to the locations of said reaction surfaces as to prevent said blade in said one of its stable positions from extending outwardly at a uniform angle throughout its length, whereby an outer end portion of said blade is elastically bent to maintain a substantial contact pressure between said electrically conductive front face portion of said blade and an electrically conductive one of said reaction surfaces when said actuator means is at one end of its path of movement.

Claim 7

Electrical contact making and breaking apparatus according to claim 5, wherein said actuator means during the final motion of a contact making sequence cooperates with said blade to change the linear distance along said front face of said blade from said actuator means to said electrically conductive one of said reaction surfaces, whereby said electrically conductive front face portion of said blade wipes against such reaction surface while contact pressure is being applied to effect a contact cleaning action.

Claim 8

Electrical contact making and breaking apparatus according to claim 4, wherein said actuator means during the initial motion of a contact breaking sequence cooperates with said blade to change the linear distance along said front face of said blade from said actuator means to said electrically conductive one of said reaction surfaces, whereby said electrically conductive front face portion of said blade wipes under pressure against such reaction surface while contact pressure is being applied to effect a contact cleaning action.

Claim 9

Electrical contact making and breaking apparatus according to claim 1 wherein said thin resilient element is a laminate comprising an electrically insulating layer of sheet material having adhered to the front surface thereof a partial layer of electrically conductive material for forming a portion of a circuit when the front face of said blade is in contact with an electrically conductive one of said reaction surfaces.

Claim 10

Electrical contact making and breaking apparatus according to claim 8, wherein said laminate includes a thin layer of spring metal sheet material adhered to the back surface of said electrically insulating layer.

Claim 11

Electrical contact making and breaking apparatus according to claim 9, wherein opposed reaction surfaces are both electrically conductive; and wherein said laminate includes a second electrically insulating layer of sheet material adhered to the back surface of said spring metal layer, and a second partial layer of electrically conductive material adhered to the back surface of said second electrically insulating layer.

Claim 12

Electrical contact making and breaking apparatus comprising: means providing a first set of opposed spaced-apart reaction surfaces at least one of which is electrically conductive; means providing a second set of opposed spaced-apart reaction surfaces spaced longitudinally from said first set; a thin resilient element having a longitudinal axis and an intersecting transverse axis located between said sets of reaction surfaces and including blades at its ends spaced apart by a middle portion, said middle portion being oriented along the plane of said axes and being tiltable about said transverse axis, means stressing said element, said stressing means biasing said blades toward a transversely curved cone configuration with the curvature of each blade increasing progressively from adjacent the respective ends toward said middle portion, each of said blades being positionally unstable when extending flat in the plane of said axes but being positionally stable when allowed to assume a coned configuration extending at an angle on either side of said plane, a first one of said blades extending at an angle on one side of said plane and including a free outer end portion protruding into the space between said reaction surfaces of said first set, said free end portion including an electrically conductive face portion for engaging an electrically conductive one of said reaction surfaces and an opposite face for engaging an opposite one of said reaction surfaces, a second one of said blades extending at an angle on the opposite side of said plane and including a free outer end portion protruding into the space between the said reaction surfaces of said second set, said free end portion including opposite faces for engaging opposite ones of said reaction surfaces, and actuator means for tilting said middle portion about said transverse axis and simultaneously moving inner portions of said blades relative to said sets of reaction surfaces, said actuator means cooperating with said element to urge said blade end portions against said reaction surfaces with increasing contact force upon tilting movement of said actuator means in one direction and to progressively buckle successive transverse cross section of said blades from adjacent said end portions toward said middle portion upon continued movement of said actuator means and thereby to increase contact force until said blades snap through their unstable central positions.

Claim 13

Electrical contact making and breaking apparatus comprising: means providing a first set of opposed spaced-apart reaction surfaces at least one of which is electrically conductive; means providing a second set of opposed spaced-apart reaction surfaces spaced longitudinally from said first set; a thin resilient element having a longitudinal axis and an intersecting transverse axis located between said sets of reaction surfaces and including blades at its ends spaced apart by a middle portion, said middle portion being oriented along the plane of said axes and being tiltable about said transverse axis, means stressing said element, said stressing means biasing said blades toward a transversely curved cone configuration with the curvature of each blade increasing progressively from adjacent the respective ends toward said middle portion, each of said blades being positionally unstable when extending flat in the plane of said axes but being positionally stable when allowed to assume a coned configuration extending at an angle on either side of said plane, a first one of said blades extending at an angle on one side of said plane and including a free outer end portion protruding into the space between said reaction surfaces of said first set, said free end portion including an electrically conductive face portion for engaging an electrically conductive one of said reaction surfaces and an opposite face for engaging an opposite one of said reaction surfaces, a second one of said blades extending at an angle on the opposite side of said plane and including a free outer end portion protruding into the space between the said reaction surfaces of said second set, said free end portion including opposite faces for engaging opposite ones of said reaction surfaces, and actuator means for tilting said middle portion about said transverse axis and simultaneously moving inner portions of said blades relative to said sets of reaction surfaces, said actuator means cooperating with said element to urge said blade end portions against said reaction surfaces with increasing contact force upon tilting movement of said actuator means in one direction and to progressively buckle successive transverse cross section of said blades from adjacent said end portions toward said middle portion upon continued movement of said actuator means and thereby to increase contact force until said blades snap through their unstable central positions.

Claim 14

Electrical contact making and breaking apparatus according to claim 11, wherein the spacings between said opposed reaction surface of said first set and between said opposed reaction surfaces of said second set are so restricted that said blades bend longitudinally at their outer end portions in the stable positions thereof to yieldingly press against said reaction surfaces.

Claim 15

Electrical contact making and breaking apparatus according to claim 12, wherein said middle portion of said thin resilient element is provided with an elongated central opening therethrough, and wherein said actuator means includes an element extending longitudinally across said opening and being connected to edge portions of said opening only at the inner marginal ends of said bistable blades.

Claim 16

Electrical contact making and breaking apparatus according to claim 13, wherein said middle portion of said thin resilient element includes flexible mounting tabs protruding into said opening at the location of said transverse axis, and in which stationary mounting means are connected to said tabs for supporting said resilient element and said actuator means.

Claim 17

Electrical contact making and breaking apparatus according to claim 13, wherein mounting means are provided and wherein said element of said actuator means is pivotally connected to said mounting means for movement about said transverse axis.

Claim 18

ElEctrical contact making and breaking apparatus according to claim 11 wherein said first set of reaction surfaces includes a plurality of spaced-apart reaction surfaces at one level and a plurality of opposing, spaced-apart reaction surfaces at another level, and wherein said free outer end portion of said first blade includes a plurality of spaced apart contact fingers positioned for cooperation with opposed ones of said reaction surfaces of said first set.

Claim 19

Electrical contact making and breaking apparatus according to claim 16 wherein all of said reaction surfaces of said first set are electrically conductive, and wherein said thin resilient element is a laminate of electrically conducting and nonconducting layers arranged so as to expose electrically conductive material on opposite faces of said contact fingers.

Claim 20

Electrical contact making and breaking apparatus according to claim 17 further characterized by mounting means connected to said middle portion of said thin resilient element, and wherein said electrically conductive material on the faces of said contact fingers is connected electrically to said mounting means.

Claim 21

Electrical switch apparatus comprising: means providing a pair of opposed reaction surfaces spaced apart from each other, at least one of said reaction surfaces being electrically conductive, a thin resilient elongated element having opposite longitudinal edges and a pair of transverse edges spaced longitudinally of said element, one of said transverse edges including a concavely curved portion, said one transverse edge being spaced from said reaction surfaces, a portion of said element adjacent the other of said transverse edges being movable alternately into engagement with said surfaces, an actuator, said actuator having an arcuate notch, said curved transverse edge of said element being received in said notch, said notch having a radius of curvature that is less than the corresponding radius of curvature of said curved transverse edge, said element including leg portions extending on opposite sides of said actuator in a direction away from said other transverse edge, means for applying tension to said leg portions, thereby causing said curved transverse edge to conform to the curvature of said notch and stressing said element to assume a transversely curved cross-sectional configuration that is convex on one face of said element, said element including electrical conductor means in position for contacting said electrically conductive reaction surface when said element engages said conductive reaction surface, and means for displacing said actuator relative to said reaction surfaces in a direction causing said element portion adjacent said other transverse edge to deflect while in engagement with one of said reaction surfaces and to flatten said element from adjacent said member progressively toward said notch until the element snaps over into engagement with the other reaction surface.

Claim 22

Electrical switch apparatus comprising: means providing a pair of opposed reaction surfaces spaced apart from each other, at least one of said reaction surfaces being electrically conductive, a thin resilient elongated element having opposite longitudinal edges and a pair of transverse edges spaced longitudinally of said element, one of said transverse edges including a concavely curved portion, said one transverse edge being spaced from said reaction surfaces, a portion of said element adjacent the other of said transverse edges being movable alternately into engagement with said surfaces, an actuator, said actuator having an arcuate notch, said curved transverse edge of said element being received in said notch, said notch having a radius of curvature that is less than the corresponding radius of curvature of said curved transverse edge, said element including leg portions extending on opposite sides of said actuator in a direction away from said other transverse edge, means for applying tension to said leg portions, thereby causing said curved transverse edge to conform to the curvature of said notch and stressing said element to assume a transversely curved cross-sectional configuration that is convex on one face of said element, said element including electrical conductor means in position for contacting said electrically conductive reaction surface when said element engages said conductive reaction surface, and means for displacing said actuator relative to said reaction surfaces in a direction causing said element portion adjacent said other transverse edge to deflect while in engagement with one of said reaction surfaces and to flatten said element from adjacent said member progressively toward said notch until the element snaps over into engagement with the other reaction surface.

Claim 23

The apparatus according to claim 19 wherein said tension means includes means for holding said element at a substantially fixed distance from said notch while said element snaps over between said reaction surfaces.

Claim 24

The apparatus according to claim 19 wherein said displacing means includes bearing means defining a transverse pivot axis for said actuator, said pivot axis being spaced from said notch, whereby swinging said actuator about said transverse axis causes said element portion that is adjacent said other transverse edge to deflect.

Claim 25

The apparatus according to claim 19 including means for maintaining a portion of said element stationary during operation of said displacing means, said element including electrical conductive means extending between said stationary portion and said element portion adjacent said other transverse edge.