Thermally adjustable electrical device enclosed within envelopes

595,615. Temperature-responsive actuating- elements. ATHERTON, A. H. Feb. 27, 1945, No. 4950. [Class 64 (ii)] [Also in Groups XXXVI and XL] A thermally - responsive device for moving an element within an evacuated or gastight vessel comprises two bowed strips 14, 15 arranged to move the element in opposite directions when heated, the strips being heated by electron bombardment from cathode 27. The emission to each strip is controlled separately by control grids 28, 29. The strips are connected to fixed rod 22 and movable rod 24, and are interconnected by a frame 18. When strip 14 is heated, a downward movement is communicated to rod 24 through frame 18 and strip 15; when strip 15 is heated an upward movement of rod 24 occurs without waiting for the cooling of the other strip. In another form, differential electronic heating of two short rods, Fig. 2 (not shown), causes angular movement of a lever arm supported across their tops and carrying the actuating rod 24. According to the Provisional Specification, heating may be accomplished by means other than electron bombardment, for example by resistance heating coils.