Patent GB-1026294-A (GB)
Title: Electric time switch
IPC: G04C23/34
Filed: 1964-06-23
Abstract: 1,026,294. Time switches. INTERNATIONAL REGISTER CO. June 23, 1964 [Dec. 2, 1963], No. 25868/64. Heading H2B. A time switch provides operation of contacts from one position to another for a short interval of time (e.g. 15 seconds) one or more (e.g. four) preset times during a relatively long period (e.g. three hours) under control of a timing means cyclically operable on a 24-hour basis, and also has means to select whether or not the said operations occur on a particular day. A synchronous motor 39 (Fig. 3) drives a 24-hour time dial 53 (Fig. 1) which can be set to the correct time of day against an index 61 on a time plate 58 which is itself settable such that an index 60 indicates on a stationary dial plate 56 the time at which the relatively long period is to commence. The drive is also geared to rotate an eccentric 84 (Fig. 4) once every one and a hlf minutes. This reciprocates a pawl 82 whose nose 83 normally idles in a gap 98 in the teeth 89 of a ratchet wheel 90. A " skipper " dial 67 carries (for example) seven pins 69 which are slidable parallel to axis 68 and is stepped once every 24 hours. If a pin 69 is depressed operation of the contacts is skipped on the corresponding day, but otherwise each pin 69 causes a lever 73 to be turned anticlockwise (Fig. 4) on the respective day at the time preset by index 60. An arm 80 on lever 73 then engages a projection 81 on pawl 82 to move it a substantially greater extent than its travel due to eccentric 84. Consequently ratchet wheel 90 is stepped and pawl 82 continues stepping it until nose 83 again idles in the gap 98; as there are one hundred and twentythree teeth 89 this takes just over three hours. Ratchet wheel 90 carriers five adjustable cams 116 to 120 (Fig. 1) and the lower edge 132 of a U-shaped latch lever extends across the paths of the four cams 116-119 to be engaged thereby at four preset times in the three-hour period and produce corresponding brief operations of a snap-action change-over switch unit 15 (Fig. 3). The operating member 25 of switch unit 15 is connected on the other side of support plate 11 to a cranked latch arm 134 which has a light spring 137 (Fig. 7) attached to its end 136, which normally biases member 25 to the position shown in Fig. 3. Latch lever 123 is mounted for limited rotary and translatory movement and when engaged by a cam (116, for example) is turned and lifted such that a notch 133 therein engages cranked arm 134 (Fig. 10, not shown). When the cam disengages the edge 132 a relatively strong spring 139 urges lever 123 clockwise, carrying arm 134 with it against the action of spring 137 and thus moving member 25 and switch unit 15 to the opposite condition to that shown in Fig. 3. An unlatch lever 143 has a projection 144 which normally urges lever 123 downwards (Fig. 7) due to a spring 150 (Fig. 4) but is lifted clear of lever 123 by a shoulder 153 on pawl 82 when the latter is moved up to step wheel 90. When pawl 82 restores after the step in which the cam disengages edge 132 the unlatch lever 143 presses latch lever 123 down, releasing the crank 134 from notch 133 so that spring 137 can restore member 25 to the position shown in Fig. 3. Switch unit 15 is therefore only maintained in the alternate position for a short period of, for example, 15 seconds each time a cam 116- 119 acts on lever 123. A second switch unit 16 (Fig. 3) has its operating member 35 connected to a lever 165 (Fig. 7) having two arms 167 and 169 respectively in the paths of cams 119 and 120, which can thus snap contact 31 between two alternate positions at preset times during the three-hour period. An arm 99 extends forwardly from pawl 82 and can be moved in the direction of arrow 104 (Fig. 1) for manual initiation of a three-hour sequence. Figs. 17 to 22 (not shown) illustrate the operation with a modified latch lever 172 which has a spring-loaded portion 180 functionally replacing the translatory movement of the whole lever 123.