Patent ID: 7220051
Filing Date: 2007-05-22
Classification: G01K

Abstract:
1. A switch responsive to temperature history, comprising: a) a body, defining a path from an attachment portion thereof to an engagement portion thereof; b) a sensing element, having a first portion mounted with the attachment portion such that motion of the first portion toward the engagement portion along the path is constrained, and having a second portion capable of first and second configurations, mounted with the engagement portion such that movement of the second portion toward the attachment portion along the path is prevented by such mounting when in the first configuration and not prevented when in the second configuration, and having a temperature responsive element made of a shape memory alloy mounted with the first and second portions such that changes in the temperature responsive element urge motion of the second portion toward the attachment portion along the path; c) a switch, mounted with the body such that motion of the second portion toward the attachment portion along the path causes a change in the state of the switch; wherein the sensing element comprises a wire made of shape memory alloy, and wherein the body defines an opening sufficient to allow passage of the wire there through, and wherein the sensing element comprises a retainer too large to pass through the opening, which retainer is removeably mounted with the wire.