GB805866A - Improvements relating to adjustable thermostatic control mechanisms for electric bread toasters - Google Patents

Abstract

805,866. Electric toasters. PROCTOR ELECTRIC CO. Jan. 21, 1957, No. 2160/67. Class 28 (1). [Also in Group XXXVII] A thermostatic control switch has a thermostatically - actuated contact and a normally stationary co-operating contact mounted on an adjustable member with an inclined face engaged by a movable cam which in addition to its primary movement can have its point of engagement along the inclined face changed, so moving the adjustable member and stationary contact to a different position where the primary adjustment of the cam will be through a different angle. The bread carriage 11 is manually lowered by knob 12 and is held by a latch until it is released by a thermostat 13 which responds to the surface temperature of a bread slice 14. The toaster has a crumb tray 15 and a colour selector finger-piece 16 with an adjustment screw 17. Thermostat 13 is mounted on a central channel support 18 forming part of the chassis of toaster 10. The thermostat comprises an L-shaped support arm 19 held with bus-bar 22 by screws 20, 21 in channel 18 being insulated from the latter by strips 23, 24 located by ears 25, 26 in channel 18. Welded to the top of arm 19 are a U- shaped bimetal 27 and a shield element 28 which co-operates with an extension 29 of support 19 to shield strip 27. Strip 27 has a short wide compensating leg 30 and a long narrow primary leg 31. Secured to the lower end of leg 31 is an L-shaped extension 32 whose end portion 33 carries a wire contact 34 to engage a relatively stationary and preferably silver contact 35 protected by a porcelain shield 36 secured to a metallic support 37. Contact 35 has a threaded extension 38 by which it is secured to L-shaped support 37 from which it is insulated by a shoulder of the porcelain shield and an insulating washer 39. Extension 38 forms a terminal for a wire 40 which with bus-bar 22 is included in the energized circuit. Support 37 is fastened to a leafspring member 41 riveted to an extension 44 of support 18 and is biased to the left, Fig. 2. A cam follower lobe 45 with a sloping face on support 37 is engaged by a manually-operated cam 46 with a narrow face extending transversely of the face of follower 45. Cam 46 is preferably formed on a spring steel member 47 secured to an arm 48 pre-biased downwardly and slotted at 50 to receive adjusting screw 17. This screw threads into the hollow rivet 49 and forms a pivotal support for arm 48, washers 51 being provided one of which is a spring washer to provide resistance to the pivotal movement of arm 48. Movement of finger-piece 16 pivoting cam 46 about rivet 49 effects adjustment of contact 35. Cam 46 may be adjusted vertically by screw 17 if the markings indicating the positions of piece 16 for different degrees of toasting prove to be incorrect.