GB1235392A - An electrical energy control assembly - Google Patents

Abstract

1,235,392. Thermal switches. KING- SEELEY THERMOS CO. 17 May, 1968 [26 Oct., 1967], No. 1493/69. Divided out of 1,235,391. Heading H1N. An hydraulically actuated temperature respon - sive switch comprises a pair of movable contacts 74, 166, Fig. 4, operable over separate temperature ranges, one contact 74 co-operating with a fixed contact 78 adjustable in position by a cam assembly 120, Fig. 5, acting through arm 80 and the other contact 166 co-operating with a fixed contact 168 adjustable in position by a calibrating screw 84. Arm 80 carrying the fixed contact 74 has a threaded stud 124 engageable with the face of cam 120 on a temperature adjustment spindle 34 of an oven. A second threaded stud 126 engages a fixed stop 130 to determine a preset, high temperature for oven self-cleaning. The arm 170 carrying fixed contact 168 is adjustable in position by threaded stud 178 and determines the preset temperature above which the contacts 166, 168 remain open to control an enabling solenoid of the oven door lock whereby opening of the oven is prevented at the higher range of operating temperatures. The movable contacts 74, 166 are operable from a Bourdon tube assembly (not shown) through link 60, 62 coupled to a rigid arm 64 of a contact arm assembly 44, 68 riveted at 70 to this casing. At normal oven temperatures resilient contact arm 68 is yieldingly restrained relative to the arm 64 by engagement in a slot 94 of a bimetal extension piece 90. At the higher self-cleaning temperatures heater 100 of the bimetal extension 90 is placed in circuit whereby the extension bends (to the right in Fig. 4) to increase the contact oven-closure and operating range of the contact 74. At the higher temperatures arm 64 also moves to engage projection 166 on the movable contact arm 154 of movable contact 166 to control the oven door lock. The control spindle 34 carrying the temperature adjustment cam 120 also carries an additional face cam 202 for setting a spring contact arm 198, 210, Figs. 3, 5, into engagement with alternative fixed contacts, as 192, 206, Fig. 5, whereby "Bake" and "Broil" heater windings are selectively connected to high and low voltage supplies at the different temperature setting. A further edge cam 246 controls main on/off contacts 248, 250. An end stop and detent device is also described for the control shaft 34, Fig. 8, in which rotation of the shaft is normally limited to about 360 degrees by engagement of legs 266, 268 on the shaft against the sides of a fixed stop 262. In order to move the control shaft 34 to its selfclean mode the shaft 34 is pushed inwardly so that the legs 266, 268 move over to straddle the stop 262. Electric circuit arrangements for the control of a solenoid preventing the opening of the oven door lock during self-clean mode are described and claimed in the Specification 1,235,391.