Patent GB-1259630-A (GB)
IPC: G04C23/16
Filed: 1969-12-30
Abstract: 1,259,630. Time switches. INTERNATIONAL REGISTER CO. 30 Dec., 1969 [18 April, 1969], No. 63243/69. Heading H1N. [Also in Division G3] A control unit for an electric or gas range comprises an interval timer section which, in addition to sounding an alarm, continuously indicates the time, and a range timer and switching section for controlling the cooking time of an oven. Both sections are driven by a synchronous electric motor, an extension of the magnetic field circuit of which drives the interval timer (vibrator) alarm. Interval timer (Figs. 1, 8).-This comprises hour, minute and second hands to indicate time and a hand 21 (Fig. 1) which is manually pre-set to a desired interval mark. The interval hand is arranged to rotate relatively slowly from the 4-hour to the 1-hour mark. During the next 45 minutes its speed is increased and during the last 15 minutes it rotates even faster. As shown, Fig. 8, a shaft 59 is driven at 1 r.p.m. through a reduction gear (not shown) by a motor (43) (Fig. 5B, not shown). A pinion 63 on the shaft drives a second hand sleeve 67 via gears 65, 66 and drives a minute hand sleeve 75 via gears 70, 71, 72, 74. A pinion 78 on the minute sleeve 75 drives through gears 79 and 80 a gear 81 secured to the hour hand sleeve. The interval hand shaft 22 is biased outwards by a spring 83. A drive dog 84 on shaft 22 locates in a slot in a cam 56 whether the shaft is in or out. A diaphragm clutch 76 secured to the minute sleeve permits rotation of the interval shaft manually for setting the time. The low- and high-speed drives facility of the interval shaft is effected by means of a relatively low speed high torque friction clutch 92 and a relatively high speed low torque (weaker spring) clutch 93 and high and low speed pinions 109, 100 respectively which engage teeth 102 on the cam 56. Moreover, the cam has no teeth on a portion of its periphery so that it engages neither the high speed nor low speed pinions while on another portion of its periphery the cam teeth are partially omitted so that it bypasses the high speed pinion 109 teeth. Between the 1 hour and 15 minute marks both pinions engage the cam teeth, but since the low speed clutch has a stronger spring the interval shaft is driven at the low speed until the cam teeth disengage the low speed pinion 100 when the drive is through the high speed clutch only. One face of the cam 56 has a cam surface (illustrated, Fig. 9, not shown) on which rides a follower pin 54. At the end of the pre-set interval the pin 54 releases a vibrator arm to vibrate in the motor field.  Cook hours and start time (Figs. 17 and 27).- To set the " start time " a shaft 144 is firstly pressed inwards until a lug 159 on a gear 158 rotatable on the shaft, clears a hole in a gear 161, and secondly is rotated manually to the set position such that the lug abuts the face of gear 161. There the lug remains until the gear 158, continuously driven by the motor via gears 176, 81 and a gear train (not shown), has rotated sufficiently to again register the lug with the hole in gear 161 at the beginning of the cook hours cycle. The initial inward movement of the shaft 144 causes a member 162 thereon to engage a shoulder 231 on a switch operating plate 232 causing it to slide and open switch contacts. When the lug re-enters the hole at the set start time the shaft and member 162 are moved forward by spring 165 and the operating plate 232 is moved by a hairpin spring and closes the contacts to begin heating of an oven. The cook hours unit is manually set by rotating a cam 190 fixed to a shaft 150. The cam has a pin 198 which projects through a slot in a gear 195 so that the cam rotates when gear 195 is driven through gears 218, 213 by gear 161 at the start of the cook cycle. The gear 195 has a minor portion without teeth so that it stops rotating when its teeth no longer engage 213. At this time a follower pin 191 engaged in a slot in the switch operating plates 232, 235 cooperates with the cam 190 to move the control plate 235 which moves a pair of plastics slide members 258 (Fig. 27) carrying contacts bridging members 268 (267), Fig. 24 (not shown), to turn OFF the oven power supply. For manual operation the cook hours shaft 150 is rotated clockwise which rotates the cam 190 to a position whereat the follower pin 191 falls into a notch and allows springs on the control plates to bias the bridging member into engagement with stationary contacts. The start time hand also indicates the time of day.