GB775653A - Improvements relating to electrically heated blankets - Google Patents

Abstract

775,653. Control systems for consumption apparatus. GENERAL ELECTRIC CO. July 11, 1952 [July 11, 1951], No. 17551/52. Class 38(4). [Also in Group XXXVI] An electrically heated blanket 1 having a pair of heater resistors or two sections of a single resistor 3 has connections between the resistors and a power supply which in a preferred embodiment include a first thermal control device 23 for controlling both resistors, a socket jack 63 and a second thermal control device 71 having a plug 70 which when inserted into the jack 63 transfers control of one of the resistors from the first to the second thermal control device. Thus a double-bed size of blanket having a respective resistor or section disposed in each side of the blanket may have a single-control of both resistors by the first device 23 or, on insertion of the plug 70, dual-control by the two devices 23, 71, the latter arrangement permitting the selective temperature control of each part where two persons are using the blanket. As shown, the blanket has a combined heating and thermosensitive element 2, and a control circuit embodying overtemperature protection, both similar to those described in Specification 696,369, which is referred to in the present Specification. However, the resistor 3 has its centre tap 7 connected to one side of the supply through the contacts 13 of relay 14 and its ends connected to the other side of the supply, one directly through the device 23 and the other through either contacts 62, 64 of jack 63 and device 23 or the jack and plug contacts and device 71. In other embodiments not shown the jack and socket are replaced by a multi-pin plug and socket connected in the multicore cable which connects the blanket to the control unit, and a combined plug-and-socket member to which the second control device is connected and which is insertable between the said multipin plug and socket to effect dual control.