Patent GB-766104-A (GB)
Title: Automatic control switch for the electric motor winding up a clockwork spring
IPC: G04C1/06
Filed: 1955-03-25
Abstract: 766,104. Snap-action switches. FRANTELLIZZI, B. March 25, 1955 [March 31, 1954], No. 8701/55. Class 38(5) [Also in Group XVIII] Automatic clock winding mechanism comprises means for completing the circuit of an electric motor geared to the winding arbor after a predtermined unwinding of the mainspring. Attached to the spring barrel 11, Fig. 1, is an insulating disc 12 and a cicular metal plate 13 having a circumferential groove 14. Spaced from the plate 13 by an insulating member 17 is a metal annular member 15 having a peripheral groove 16. Brushes 18, 19 in the circuit of an electric motor 20 engage the grooves 14, 16 respectively. The motor 20 is geared to a gear 27 fixed to the winding arbor 21. A sleeve 22 fixed by a dog clutch to the gear 27 has a finger 23 which steps on a star wheel 29, Fig. 2, clockwise during unwinding and counterclockwise during winding of the mainspring. A spring pawl 32 accurately locates the star wheel 29 in its rest positions and ensures that each step thereof is completed with a snap action. A pin 35 carried by the star wheel 29 is normally embraced by the limbs of a fork member 36 movable about a pivot 37. Fig. 2 shows the position with the mainspring fully wound. Electrically connected to the member 15 is a metal arm 41 urged counter-clockwise by a spring 44 to a position determined by a pin 45 and carrying a contact 40. A link 47 pivoted at 48 to the fork member 36 has a slot 49 through which passes a pin 43 on the arm 41. A two-armed lever 52 pivoted at 53 to the plate 13 carries at one end a contact 50 and at the other end co-operates with the pivot 37 of the fork 36 whereby the amplitude of movement of the lever 52 is limited. A pin 56 carried by the lever 36 engages a hole 55 in the lever 52. The lever 52 is located in its two end positions by a spring pressed ball 58, Fig. 1. which engages one or other of two holes in a metal support 60. A plate 64, Fig. 2, engaged by the pin 56 carries a pin 62 which passes through a flanged extension 61 of the lever 52 and is surrounded by a compression spring 63. As the mainspring unwinds the finger 23 steps the star wheel 29 clockwise and the pin 35 rocks the lever 36. During the first step the link 47 is moved so that the lower end of the slot 49 engages the pin 43, and the lever 41 is moved clockwise. At the end of the second step the pin 56 is located to the left of the line joining 37 and 53 and the spring 63 rocks the two-armel lever 52 clockwise. Any tendency of the pin 58 to lock the lever 52 against the action of the spring 63 will be overcome by the pin 56 striking the periphery of the hole 55. The ball 58 is then located in the other hole and contact 50 meets contact 40 and moves the lever 41 slightly further clockwise the contacts sliding over each other until the lever 41 is arrested by pin 45. The electric motor now winds up the mainspring. Under the action of the spring 44 the contact 40 initially follows the contact 50 in its return movement until at the end of the second counter-clockwise step of the star wheel 29 the spring 63 moves the contact 50 to its off position. In a modification, Fig. 7, the insulating plate 12 is moulded on to the barrel 11 and has a screw threaded sleeve 75 on which the base plate 13 is screwed preferably in a direction opposite to that of rotation of the barrel