998, 538. Bi-metallic thermo-responsive devices. MECHANICAL PRODUCTS Inc. April 26, 1962 [May 1, 1961], No. 16037/62. Heading G1D. [Also in Division H2] A snap-acting thermo-responsive device comprises an elongated bi-metallic blade 10 prestressed by an embossed portion 60 extending along a substantial length of its length projecting beyond a forked support 22, thereby minimizing pre-snap creep of the blade 10. The support 22 forms a terminal held in pressure contact with the fixed end 30 of the blade 10 and electrically connected to a lead-in wire 24. A movable contact 50 is secured to blade 10 in alignment with a fixed contact 16 secured to conductive casing 14. In a modification, Figs. 4 to 6 (not shown) a conductive casing 114 is enclosed in a plastic sleeve 115. A bimetallic blade 125 has an embossed portion 160 extending substantially the whole of its unsupported length beyond forked support 130. The embossed portion 160 is formed by dies 200, 202 Figs. 8 and 9 (not shown).