GB1343959A - Clock striking mechanisms - Google Patents

Abstract

1343959 Striking clocks JAZ SA 4 May 1971 [11 May 1970] 13060/71 Heading G3T In a striking mechanism having a counting wheel 20 driven by an electric motor 29 which is energized via contacts 44, 45, the contacts are opened to stop the motor after the desired number of strikes by axial movement of a spindle 24 which is rotationally driven by the motor 29 and carries a worm 23 meshing with a gear wheel 22 which is fast with the counting wheel 20. Striking is initiated by a cam 5 which is rotated once per hour by a clock movement and co-operates with a lever 7 pivoted on a support 9. When the lever 7 is allowed to drop from the chain-line position under the force of spring 8, its arm 7b engages a toe 51 of stop lever 14 and causes the latter to pivot clockwise about a spindle 15 against a spring 16, thus disengaging lever arm 14b from notches 19 of the counting wheel 20. This frees the wheel 20, and the spindle 24 is displaced to the right under the bias of spring 47, the worm 23 acting as a rack on the wheel 22 and thus rotating the counting wheel 20 in the direction of arrow F. The spindle displacement also allows the contacts 44, 45 to close, thus energizing motor 29 which drives the wheel 20 in the same direction until the arm 14b engages the next notch 19 therein to lock the wheel. Further rotation of the motor then acts to displace the spindle 24 to the left, opening the contacts 44, 45 and de-energizing the motor. The number of strikes is thus determined by the spacing of the notches 19. The sounds are produced by hammers 36, 37 which are raised by cams 30, 31 on the spindle 24 and which strike bells (38, 39) Fig.2 (not shown). The mechanism may be made inoperative to silence the strikes by rotation of a member 55 to keep open the contacts 44, 45. Striking may be temporarily silenced, e.g. at night, by a further lever (not shown) which acts on the hammers 36, 37. The mechanism may be arranged to strike only one bell at the half-hours or hours by means of an additional cam (52), Figs. 3, 4 (not shown) which rotates with the cam 5 and renders the hammer 37 inoperative. A disc 48 rotating with the wheel 20 carries graduations which correspond to the notches 19 and are visible through an aperture (49) in frame plate 1 so that the mechanism may be set by inspection to line up with the indicated time. This is achieved by manual operation of the lever 14 via an external push-button. In an alternative embodiment, a striking mechanism is assembled as an independent unit on a frame plate (57), Figs. 5, 6 (not shown) which carries a battery (58) and a horological movement. Striking is automatically silenced at night by means of a cam (116), Fig. 7 (not shown) which is rotated once every twenty four hours and restrains the hammers.