Patent GB-529393-A (GB)
Title: Improvements in mechanically operated date indicators
IPC: G04B19/253
Filed: 1939-05-16
Abstract: 529,393. Date-indicators. PAAUWE'S VOLAUTOMATISCHE KALENDERUURWERKEN N.V. May 16, 1939, No. 14657. Convention date, May 17, 1938. [Class 106 (iv)] Relates to clock-driven indicators having rotary elements indicating day of the week, of the month and year respectively, and combines means driven by the month element, during a movement to indicate a change of month, for automatically advancing the day of the month element through the unrequired interval for months of less than 31 days. Concentric rings 1, 2, 3 bearing names of the months, numbers 1-31, and names of days respectively are mounted on a base comprising apertured discs 4, 4a. The rings are moved by the hour hand arbor of a clock passing through the sleeve 7. A lever 14 oscillating about a pivot 16 carries three pawls 11, 12, 13. The inner ring 3 has seven ratchet teeth and is moved one step at the end of each day by pawl 13. The pawl 12 engages a set of 31 pins 15 on ring 2 and moves it on one step at the end of the day. The outer ring 1 is fed at the end of the month by pawl 11 engaging one of 12 teeth 31. The ring 2 rotates in the opposite direction to discs 1 and 3. The arm 14 which completes a cycle of movement about its pivot 16 in 24 hours is driven by a pin 19 on a disc 20 frictionally carried on the hour arbor. In the case of a 24 hour clock the arm 14 is moved directly by pin 19. In the case of 12 hour dials, a bell crank lever 22 pivoted to the arm 14 co-operates with the pin 19 and pawl 13 so that the arm completes its cycle at every second rotation of pin 19. A spring 52 retains pawls 12, 13 in operative position and also retains the lever 22. A notched lever 25 pivoted at 23 on arm 14 engages a fixed projection 39 in the initial position of the arm 14. A spring 24 connects the lever 25 and pawl 11 and retains the lever 25 until released by a projection 53 on lever 22. The pawl 11 is rendered inoperative except at the last day of the month by a lever 26 pivoted at 37. The day indicating ring 2 has recesses 28a, 28b, 28c. A pin 54 on lever 26 is adapted to enter these recesses. Up to the 28th day of each month the pawl 11 is held clear of the teeth on ring 1 by the end of lever 26 away from pin 54. On the 29th day the pin 54 engages recess 28a. The teeth on inner edge of ring 1 are of different height. The tooth 29 corresponding to February is highest, while teeth 30, 31 corresponding to months of 30 and 31 days, are medium and lowest. In the position shown, tooth 29 is engaged by pawl 11 and the ring 1 is moved from February to March. The ring 2 must be fed three more steps to bring it to read " 1." For this purpose, a wheel 32 is provided. The ring 2 carries a single stud 33a-33d at each position for a 30-day month, and a group of three studs 34a-34c at the position for February. Normally at a 31-day month there is no stud and the month ring is advanced simultaneously with the ring 2 changing from 31 to 1. For 30 day months a single stud 33a &c. meshes with 32 and causes ring 2 to rotate two steps from 30 to 1. Similarly the group 33a-33d causes ring 2 to rotate from 28 to 1. For leap years a cam 40 is rotated sometime before 29th day so that it is engaged by pawl 11 and the latter is prevented from engaging tooth 29. During the 29th day the cam is moved back. Levers are provided at the front of the discs for advancing the discs by hand. Specification 456,809 is referred to.