GB1123146A - Drafting board structure - Google Patents

Abstract

1,123,146. Table tops. HUGHES-OWENS CO. Ltd. 30 Nov., 1966 [17 Feb., 1966], No. 53528/66. Heading A4H. [Also in Divisions B5 and B6] A drawing board structure comprises a layer 6 of expanded polystyrene, sheets F of aluminium glued to both sides of the layer 6, and a layer 11 of linoleum which is applied to the top surface to provide a drawing surface. The edges of the sheet F are secured to rigid aluminium or plywood, members 8 by rivets or bolts 9. Aluminium channel members 10 trim the outer edges of the structure, and one channel member (10a, Fig. 1) is shaped to form a pencil rack. The board is pivotally mounted for angular adjustment about a horizontal axis between a pair of legs (3, Fig. 1) of a support (2). 1,123,243. Timing device. SMITHS INDUSTRIES Ltd. 10 Feb., 1967 [15 Feb., 1966], No. 6689/66. Heading A4D. [Also in Divisions G3, H1 and H3] A timing circuit for use with heating devices such as an oven heating element and boiling rings comprises adjustable controls 1, 3, 4, 5 for setting the required temperature for each heating device, a potentiometer 35 for switching off all the heating devices at the end of a pre-set time and controls 10-13 for setting the duration of operation of each heating device. A pointer 8 is attached to a disc of the potentiometer and indicates on a clock 6 the time at which the heating devices are to be turned off. A wiper engaging the potentiometer wire on the disc is rotated by a synchronous motor at a speed of one revolution in twelve hours. Each control 10-13 comprises a potentiometer 47, the setting of which determines the instant that a transistor 41 starts to conduct and therefore the instant at which a transistor 48 ceases to conduct. When the transistor 48 ceases to conduct a transistor 68 conducts and a relay 71 switches on the heating device. At the time indicated by the pointer 8, the wiper disengages the potentiometer wire and the transistor 41 ceases to conduct so that the heating device is switched off. The transistor 68 also ceases to conduct when a transistor 58 conducts, the state of the latter being governed by the respective one of the controls 1, 3, 4, 5 each of which comprises a variable resistor 61. The resistor 61 is in series with a negative temperature coefficient resistor 55 located close to the heating device to enable the operating temperature of the heating device to be pre-set. The potentiometer is ganged to a switch 69 so that the potentiometer may be set to a position in which the switch is open thus allowing manual instead of timed operation of the heating device.