Patent GB-708237-A (GB)
Title: Improvements in and relating to calendar mechanisms
IPC: G04B19/253
Filed: 1952-12-22
Abstract: 708,237. Calendars. KAMPEN, M. T. VAN. Dec. 22, 1952 [Dec. 28, 1951], No. 32455/52. Class 106 (4) A mechanically-operated calendar mechanism comprises a driving arm 3 provided with a catch 5 with a pin 6 adapted to be swung to and fro about a bushing 2 by the shaft of the hour-hand of a clock or by hand and at least three discs 10, 13, 15 bearing day names, date numbers and month names respectively, rotatably mounted behind a dial plate 1 and provided with peripheral teeth adapted to be brought into the path of the catch 5. The day and month discs have seven and twelve teeth respectively disposed equiangularly, the number disc having 31 teeth of which the three successive teeth provided for the advance of the number disc from the numbers 29, 30 and 31 to the numbers 30, 31 and 1 are equally spaced apart by equal angles of less than 10 degrees, say 9 degrees. The remaining teeth are angularly spaced by greater equal angles, the diameter of the day disc 10 being greater than that of the month disc 13 whose diameter is greater than the number disc 15, the catch 5 being guided during the active oscillation of the arm 3 by a track provided on the periphery of a fixed disc 7 having one or more parts 27, 28 of which the radius is greater than that of the day disc 10, and being provided with a recess, of which the edge forms the track and the shape is such that the teeth of the day disc 10 are left uncovered by the fixed disc through an arc a extending through an angle of <SP>2</SP>/ 7  of 360 degrees at the most. Within this arc the teeth of the number disc 15 are left uncovered through an arc b extending through twice the angle between the teeth, which are angularly spaced apart less than 10 degrees at the most. The teeth of the month disc 13 are left uncovered through two arcs c, d of 30 degrees at the most, which join each other or are spaced apart by an arc of 30 degrees. The arrangement is such that the catch 5 when moving along the edge of the recess of the fixed disc 7 engages at least a tooth of the day disc 10 and a tooth of the number disc 15 in order to advance these discs one step, the month disc 13 being provided with holes 34 to 46, Fig. 6, viz. two holes 35, 36 for February and one for each of the other months, the holes being distributed on a circle round the axis of the discs and angularly spaced apart in accordance with the number of days of the month. The number disc 15 is provided with a spring-loaded pin 31, Fig. 8, which for coupling the month disc 13 to the number disc 15 is adapted to be passed through a slot 33, Fig. 7, in the fixed disc 7 and to be introduced into one of the holes 34 to 46 of the month disc 13, the coupling being made when the number disc 15 is advanced after showing the last date of the month, but being broken again when the date " 1 " comes into view. After the coupling is made the month disc is moved part of its step by the number disc when the latter is advanced one step by the catch, so that one of the teeth of the month disc moves into the path of the catch within the arc d of the track on the fixed disc 7 and then the step of the month disc is completed by the catch engaging its exposed tooth during its further travel along the track. During completion of the step of the month disc, after a month having less than 31 days has finished, the number disc is moved in its turn by the month disc until the number 1 is brought into view, whereby the coupling between the discs is broken again. Appropriate recesses 23, 24 between the teeth of the day and month discs and a window 25 in the fixed disc 7 allow the calendar data on the superimposed discs to be made visible through windows 20, 21, 22 in a front dial plate 1 and a spring 29 secured thereto ensures that during the return half of each oscillation of the arm 3, the pin 6 is guided outside the spring 29 and is therefore prevented from interfering with the calendar setting by frictional contact with the discs. The slot 33 in the fixed disc 7 extends from its inlet edge 47 to its outlet edge 48 through an arc of 33 degrees. The holes 34 to 46 in the month disc are so disposed that when a 31-day month is displayed a hole lies under the slot 33 at a distance of 3 degrees from the outlet edge 48, when a 30-day month is displayed one lies at a distance of 3 degrees + 333 degrees/28 from the edge 48 and when February is displayed the holes 35, 36 lie at distances of 3 degrees + 18 degrees and 3 degrees + 27 degrees respectively from the edge 48. Thus in a 31-day month the pin 31 on the number disc engages a hole while the date is changing from 31 to 1 so that the month disc is advanced 3 degrees to move a month tooth from under the part 26 of the guide track so that in its continued forward movement the pin 6 engages the month disc and advances it to display the next month name, the date disc having been uncoupled by the edge 48 after completing the 3 degrees. In a 30-day month the pin 31 engages a hole while the date is changing from 30 to 31 and the month disc is advanced 3 degrees, the pin 6 engages a month tooth and the month disc carries the date disc forward another 333 degrees/28 to change the date to 1 whereupon the edge 48 uncouples the date disc and the month disc completes its advance to display the next month. In a 28-day February the pin 31 enters the hole 36 during the advance from 28 to 29 and after the 3 degrees advance the month disc carries the date disc through a further 27 degrees equivalent to the final three steps necessary to display the date 1. In leap year the long arm 49 of a conventional rotatable cross, advanced yearly through a quarter turn by a pin 50 on the month disc, obscures the hole 36 so that the pin 31 enters the hole 35 as the date changes from 29 to 30 and after the 3 degrees advance the month disc drives the date disc the 18 degrees necessary to change the date to 1. Driving by clockwork and manually.-The arm 3 is oscillated daily through the hour-hand shaft of the clockwork by a pin 4 on a 24-hour wheel engaging a curved surface 52. When the pin 4 is free of the surface 52 the arm 3 can be turned freely between limits by means of a grip 51. To reset the date 'from Wednesday the 12th October to Sunday the 27th December the arm 3 is moved to and fro through its whole stroke to change the day displayed to Saturday and the date to 15 and then the arm is swung counter clockwise free of the tongue 27 and back clockwise into a recess 53 where a month tooth is exposed but the date teeth are hidden and when the pin 6 has engaged a month tooth the arm 3 is swung to and fro, but not beyond the free end of the spring 29, twice to display December. Now the arm is oscillated through the arc " b " to advance the date from 15 to 27, at the end of the final stroke the arm is moved its full distance forward to complete the already begun advance of the day disc from Saturday to Sunday and then the arm is brought back to its initial position outside the tongue 27 ready for the clockwork to take over the drive. Moon phase.-Within a fixed ring 9 a toothed disc 54 on the bushing 2 is driven by a resilient hook 56 fixed to the arm 3 through an angle determined by a recess 57 in a fixed plate 58 and displays an image of the moon behind a crescentshaped window 55.