Patent GB-473293-A (GB)
Title: Improvements in mechanical date indicators
IPC: G04B19/253
Filed: 1936-04-08
Abstract: 473,293. Date indicators. PAULIN, J. G. April 8, 1936, Nos. 10406 and 10407. Convention dates, April 9, 1935 and March 31, 1936. [Class 106 (iv)] A date indicator comprises date-figure and month members actuated by an oscillated device which also moves the date-figure member the necessary number of extra steps at the end of a short month, this extra movement being controlled by circumferentially-spaced cams on the month member. A lever 5 is oscillated (by a clock or otherwise) at midnight from the position shown in Fig. 1 to that shown in Fig. 3 and back again. The lever carries a pawl 6 controlled by a spring 11 and rocked about its pivot 8 by a fixed cam 15. Towards the end of the return stroke of the lever 5, the tip 12 of the pawl is thus engaged with teeth 4 on a date-figure ring 1 and advances this ring through one step. A month ring 18 is driven from the date-figure ring by means not shown. The month ring has a series of cams 31 ... 35 spaced around it in positions corresponding to April, June, September, November and February. The February cam occupies a greater peripheral space than the other cams and in non-leap years its length is further increased by an auxiliary cam 25. When the date-figure ring is moved to 28th February in a non-leap year, a blocking member 30 carried on a spring 29 secured to the date-figure member 1 at 28 moves on to the top of the auxiliary cam 25 as shown in Fig. 3, so that when the lever 5 is rocked anticlockwise at midnight on the 28th, an extension 13 of the pawl 6 engages the blocking member 30 whereby the pawl is forced into engagement with the teeth on the date-figure ring and, on the clockwise movement of the lever 5, the datefigure ring is advanced four steps to indicate " 1." During the movement of the lever 5 on the 30th of the other short months, the blocking member 30 moves on to one of the cams 31 ... 34 and rocks the pawl 6 into engagement with the teeth of the date-figure ring to advance this ring to indicate " 1." The auxiliary cam 25 is carried on a lever 22 pivoted at 23 to the month member and having an end 24 co-operating with a disc 20 driven through one rotation in four years. On 28th February in normal years the end 24 of the lever 23 rests in a recess 21a of the disc 20 thus allowing the auxiliary cam 25 to move into active position. In leap years the unrecessed part of the disc 20 rocks the lever 23 clockwise at the end of February and the auxiliary cam 25 is moved to inactive position, the blocking member 30 moving on to the main cam 35 on the 29th to cause a movement of three steps to be given to the date figure ring at midnight on that date. In a modification, Fig. 5, a lever 59 oscillated anticlockwise and back again at midnight carries a pawl 60 which advances a day-name ring 50. It carries another pawl 61 which drives the date-figure ring 54 through one step when the said pawl moves clear of a fixed cam 64. A third pawl 62 is also pivoted on the lever 59 and at the end of a short month this pawl is allowed to drop into a notch 71 on the month member, whereby it engages a pin 66 on the date-figure ring to advance this ring the required number of extra steps. In February of leap year a member 58 is swung by a spring to decrease the effective length of the notch 71, this swinging being possible since the other end of the member 58 is not at this time engaged by a cam on a disc 56 rotated once in four years.