the head being disposed on the underside of the element 36 the upper portion of the element comprising a stem terminating in a round dome and secured in the element 36 by a spring washer 42 still more specifically the switch assembly 32 is rivetted as at 44 to a plate 46 which as shown is bolted at 48 fig2 to the soleplate the assembly includes a sheetmetal lower blade 50 insulated from the rivet 44 and plate 46 and an insulation block means 52 preferably ceramic the upper blade 34 and the lower blade 50 carry contact buttons 54 and 56 respectively the lower blade 50 is biased upward by its natural resilience and carries a downwardly offset dog leg portion 58 the upper surface of the offset portion 58 continuously engages the head of the element 40 as shown fig5 the blades 34 and 50 may be channel shaped to stiffen them the upward bias of the blade being achieved at a section 50a thereof immediately adjacent the block means 52 the outer end of the blade 34 may be deflected at an elbow 34a as shown and terminate in an insulated section 34b which is apertured and receives the end of the link 30 the operation of the structure as shown before is conventional depending upon the setting of lever 18 and in turn the height of the end 34b of blade 34 and depending on the disposition of the bimetallic element 36 that is whether it holds the offset portion 58 down or not the.