Patent GB-467829-A (GB)
Title: Improvements in and relating to date indicators especially applicable to clocks
IPC: G04B19/243
Filed: 1935-12-23
Abstract: 467,829. Date indicators. ELMS, R. Dec. 23, 1935, No. 35552. [Class 106 (iv)] A ratchet wheel actuating the date-figure mechanism of a date indicator is controlled by two rotatable members, one having a gap in its periphery and always rotating in synchronism with the ratchet wheel, the other having peripheral notches corresponding to the lengths of the months and being rotated one step per month. Date-figure indication. A snail cam 15, Fig. 5, is secured to a shaft 9 which is rotated by a clock, once in twenty-four hours. The cam engages a roller 21 on a lever 19 and rocks this lever about its pivot 20. The lever 19 carries a pawl 24 which advances a thirtyone-toothed ratchet wheel 27 by one tooth each day. The ratchet wheel 27 is connected to a concentric disc 106 on which are printed the date figures. The stroke of the lever 19 is normally limited by a pin 22 on this lever contacting with the periphery of a composite disc 2, 3, Fig. 9, secured to the ratchet wheel 27. This disc comprises a main portion 23 provided with a gap 37, the effective extent of the gap being normally limited by a mask 39 attached to a disc 38 rotating with the disc 23. On the 30th day of a month other than February, the gap 37 in the disc 23 is opposite the pin 22. If the month has thirty-one days, the lover can still make only its normal movement, since a pin 19a, Fig. 5, concentric with the roller 21 engages a tooth 119 of a disc 14 freely mounted on the shaft 9. If the month has thirty days, a notch 116 in the.disc 14 is beneath the pin 19a and the lever 19 can thus follow the snail cam 15 under the pressure of the spring 28 until the pin rests at the bottom of the notch. The ratchet wheel 27 is thus moved through two steps and the date indication changed from " 30 " to "1." At the next actuation, the disc 23 secured to the ratchet wheel 27 is advanced after one step of movement to a position in which its periphery lies beneath the roller 22 and this and the following movements of the lever 19 and wheel 27 are limited to one step, notwithstanding that the notch 116 is still beneath the pin 19a. The disc 14 is advanced through one step during the middle of each month by a pawl 36, Fig. 11, carried by a lever 34 pivoted at 65 and actuated by a pin 33 on the ratchet wheel 27. The disc 14 is divided into forty-eight parts and rotates once in four years, leap years thus being provided for. When the disc 14 is stepped into its normal February position, a deep notch 118 comes beneath the pin 19a. At the same time, a pin 59 on the disc 14 rocks one end of a lever 58, Fig. 9, about its pivot 55 so that the other end of the lever rocks a three-armed lever 47 pivoted on the ratchet wheel 27. One arm of the lever 47 engages the disc 38 carrying the mask 39, the disc 38 thus being moved relatively to the disc 23 to increase the extent of the gap 37. Thus, the gap 37 comes under the roller 22, Fig. 5, on the 28th of the month and, since the deep notch 118 is beneath the pin 19a at the same time, the lever 19 makes a large movement to advance the ratchet wheel 27 by four steps, the date indication then being changed from " 28 " to "1." In February of leap year, a notch 117, not so deep as the notch 118, comes beneath the pin 19a. The lever 58 is rocked in leap year by a pin 59a so arranged on the disc 14 that the gap 37 is increased by a less extent than during a normal February, whereby the single-step movement continues until the 29th day, whereupon the roller 22 moves into the gap 37 and the notch 117 permits a three-step movement of the lever 19. The gap is always reduced to its normal size during March by the action of the roller 22 on a lever 48 pivoted on the disc 23 and engaging the lever 47. In a modification, Figs. 18 and 19, the date figures are displayed on two drums 156, 160. The lever 19 is arranged so that it normally has a stroke of two steps which is increased to three, four, or five steps at the end of a month as previously described. The lever has two pawls 24a, 24, the latter acting on the ratchet wheel 27 and the former on a disc secured to the ratchet wheel and having only two teeth 27a. The pawl 24 is prevented from moving the ratchet wheel through more than one tooth by a stop 141. This stop does not act on the pawl 24a and thus on the 11th and 21st of the month the pawl 24a acts on the teeth 27a to advance the ratchet wheel 27 through two steps. The ratchet wheel 27 has thirtythree teeth and is geared to the drum 156 to rotate this drum through <1>/11th revolution at each step. The drum carries the numerals 0, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9. The two steps of movement given to the ratchet on the 11th and 21st cause the second numeral " 1 " to be passed over, but at the end of a thirty-one day month the drums show " 31," " 1," " 2," &c. The tens drum 160 is divided into nine spaces and connected to the drum 156 by transfer teeth 152, transfer pinion 162, locking pinion 163 and gearing 164. The tens drum 160 is marked: '' Blank," " Blank," 1, 1, 1, 2, 2, 2, 3. Transfer from the units drum occurs when this drum passes from 9-0, 1-1, and 2-3. Month-name indication. The ratchet wheel 27, Fig. 5, which is rotated once every month carries a pinion 69 geared through a pinion 71 to a pinion 72 secured to a snail cam 76 on which is pressed by a spring 84 a pin 83 attached to a curved arm 81. When the pin 83 falls over the point of the snail cam, the curved arm contacts with a pin 80'on a one-toothed disc 79, whereby this disc is suddenly advanced through about 90‹ into the position shown. The pin 80 extends through a slot 77 in the snail cam and later the one-tooth disc is driven bv this connection. During the sudden movement, the tooth 79 advances a disc 85 connected to the month-name disc 93. Day-name indication. The day-name disc is driven direct from the clock through gearing including a sudden-movement device similar to that used for the month-name drive described above. Specification 467,830 is referred to.