Patent ID: 6893155

Claim:
A cooking thermometer having an audible alarm, comprising: a generally cylindrical housing assembly and a substantially hollow skewer extending coaxially therefrom, said skewer having a proximal end contiguous to said housing assembly and a sharpened distal end; said housing assembly further including a temperature indicia plate, a pivoting pointer movable over said indicia plate; a set temperature needle selectably manually positionable over said indicia plate, and a tension wound spring-type audible alarm mechanism activated by alignment of said set temperature needle and said pointer, a linear segment of heat contractible shape memory alloy wire disposed within said skewer and having a first end and a second end wherein said first end is fastened to said distal end of said skewer, said shape memory alloy wire being selected such that said wire begins phase transformation at a first lower temperature M S and completes phase transformation at a second higher temperature A F ; a connecting wire having first and second ends wherein a lower portion of said connecting wire is disposed within said skewer and an upper portion extends into said cylindrical housing, said connecting wire having a first end secured to said second end of said shape memory alloy wire; a wire guide member positioned in said housing proximate said skewer including a curvilinear passage therein adapted to allow sliding displacement of said connecting wire therethrough, wherein said connecting wire extends coaxially out of said skewer into said wire guide member and said second end of said connecting wire extends out of said wire guide member in a direction approximately normal to said skewer; a gear assembly rotatably mounted in said housing wherein said second end of said connecting wire is fixedly attached to said gear assembly whereby sliding displacement of said connecting wire through said wire guide member causes the rotation of said gear assembly, which rotation is transmitted to said pointer through a cooperating gear train; and a spring biasing means applied to said gear assembly constructed and arranged to exert stress on said shape memory alloy wire via said gear assembly, said spring biasing means having parameters which are configured to impart desired phase transformation characteristics to said shape memory alloy wire whereby optimization of said phase transformation and linearity of temperature response are obtained.