GB1481401A - Pyrolytic self-cleaning cooker ovens - Google Patents

Abstract

1481401 Self-cleaing electric ovens ETABS EUGENE SCHOLTES 3 Oct 1975 [9 Oot 1974] 40552/75 Addition to 1457579 Heading F4W [Also in Divisions E2 and H2] An electric oven as claimed in Specification 1,457,579, which has means for locking the door when the oven is being cleaned by heating to a high temperature, is modified so that each of the two actuating windings of the door-locking bolt is de-energized as soon as it has operated the bolt. Fig. 2 shows the circuit during the cleaning operation. Besides the normal heating resistors 2b, 3b, there is a resistor 5b for raising the oven to cleaning temperature and a heater 6b for heating a catalyst for destroying the fumes. All these resistors are energized through contacts of the main control switch 1b, the circuit of resistors 2b, 3b and 5b being by way of line 65 and thermostat switch 11b, which changes over when the temperature exceeds normal cooking temperatures, indicating that the cleaning operation has begun. When switch 11b changes to contact t the resistors remain energized by a circuit over line 67 through a two-way switch 13b, which is changed to contact v by the shooting of the bolt 30b. The common terminal w of switch 13b is connected by line 68 to contact j of the main control switch. In the "cleaning" position of this switch contact j is connected to the power supply terminal I at contact b. Also the winding 33b is connected over line 72 to the supply terminal II via contacts a-h, switch 40b and contacts f, o and g. The other end of this winding is connected over line 73 to contact s of switch 13b. As soon as the main switch is turned to the cleaning position the winding 33b is energized, switch 13b being at this time on contact s. This causes the bolt to be shot, changing the switch to contact v so as to de-energize winding 33b. The bolt remains shot, preventing the door being opened until the other winding 32b is energized at the end of the cleaning operation This winding is connected through contact v of switch 13b so that as soon as it has returned the bolt to the withdrawn position it is deenergized by change-over of switch 13b (Fig. 4, not shown). A locking bolt for a door swinging about its lower edge is shown in Fig. 5. The bolt, which is the cranked end of a rotating rod 50, is adapted to engage with a keeper plate 20b. The bolt is displaced to and from the locking position by opposite electromagnets 32b, 33b acting through a slotted bail 56 on the cranked end 50a of rod 50. A flat on the rod operates the switch 13b as it turns into and out of the locking position.