Patent GB-663864-A (GB)
Title: Improvements in date indicators
IPC: G04B19/243
Filed: 1948-06-14
Abstract: 663,864. Date indicators. ELMS, R. June 14, 1948, No. 15963/48. Class 106 (iv). A date indicator with a day-ofthe-month indicator comprising 31 plates pivoted on flanges on a shaft and driven by a pawl-and-ratchet, has a spring-loaded detent for retaining the ratchet-wheel with the plates in display position against the unbalanced load of the plates, means for varying the amplitude of reciprocation of the pawl on the 28th 29th and 30th operation to suit the days of the month and means for avoiding undue load on the clockwork, including an upper adjustable stop for successively releasing and synchronizing the release-plates, and a lower resilient stop for arresting and retaining the released plates in display position. Date-figure indication. The days of the month are marked on thirtyone plates 200, Fig. 13, pivoted on pins 201 in flanges 203 fixed on a spindle 204 which is rotated intermittently and carries the plates around so that they are arrested successively by stops 205, 206 carried on a, bar 216, the stop 206 being adjustably fixed in an elongated hole. At each movement of the spindle 204 a plate 200 passes under each stop 205, 206, the foremost falling to expose its numeral and pass a latch 207 where a number of plates accumulate against a spring tongue 212, the rearmost of these slipping over the tongue to be carried round again. The spindle 204 is driven from electric clockwork mechanism controlled by date indicator mechanism, similar to that described in Specification 467,829. Manual setting. A shaft 227, Fig. 5, may be turned by a hand knob against a spring 233 to cause a cam 228 to co-operate with a roller 229 on a bell-crank lever 230 linked to rocker mechanism 19, described in Specification 467,829, through which the date mechanism is actuated, the coil-spring 28 replacing the former spring 28. Month-name indication. Plates marked with month names alternating with blank plates are pivoted on two flanges fixed on a shaft 238 which is advanced at the end of each month to allow two plates to fall and expose the next month name. The month-name shaft 238 is driven from the date shaft 204 through transfer mechanism comprising a disc 246, Fig. 9, with two teeth 250 and a mutilated pinion 254, the drive being assisted by a weight 264, through pawl 269 and ratchet 267, to counteract the bias of the unbalanced system of month plates. The disc 246 is mounted on a stud and clamped between a cam 270, Fig. 9, and the last gear of a train driven from the shaft 204 and is formed with a flange 248, Fig. 11, and rim 249, the rim having 'a gap 251 opposite the teeth 250. During each month the cam 270 acting on an arm 281 of a lever 265 carrying the weight 264, holds the pawl 269 free from the ratchet 267 and the unbalanced month indicators are braked by the locking action of two arms 255 on the rim 249 and, subsequently, of two teeth in the mutilated part of pinion 254 on the flange 248. At the end of the month the cam 270 releases the weight 264 so that the pawl 269 engages the ratchet 267 and the normal teeth of pinion 254 mesh with the teeth 250 to be driven thereby and so drive a gear 257 to advance the month name shaft 238. A leap-year indicator is driven from the shaft 238. The multi-plate indicator for the month names may be replaced by a drum driven similarly from the shaft of the days of the month indicator. Specifications 467,829 and 508,799, [Group XXXV], are referred to.