GB1408416A - Digital clock - Google Patents

Abstract

1408416 Digital clocks GENERAL ELECTRIC CO 30 Oct 1972 [8 Nov 1971] 49846/72 Heading G3T In a digital clock having units and tens of minutes indicators controlled by cams 52, 54 on spaced, parallel axes, the cams are driven at their appropriate rates by a pawl lever 84 pivotally mounted on a drive lever 86 which is displaced through one cycle per minute, a pawl 112 on the lever 84 being held in contact with the units cam 52 by a counterweight portion 113 of the lever and the lever being displaced once each ten minutes by an enlarged tooth 122 on that cam so that a further pawl 120 engages the tens cam 54 and the two cams are advanced together. The drive lever 86 is pivotally mounted by its shaft 88 and has cam surfaces 102, 104 which are engaged by an eccentric roller 106 on a gear 108 to ensure rapid indexing. The gear 108 is driven by synchronous motor pinion 110. The cam 54 is thus rotated once every two hours and has lugs 136, 138 to engage a six-slot geneva wheel 124, a gear 134 on which meshes with gear 130 on hours cam 56 so that the latter is indexed once per hour. The indicators comprise horizontal and vertical bands on vertically moving shutters 30, 32, 34 and horizontally moving shutters 46, 48, 50 and each of the cams 52, 54, 56 actuates a vertical and a horizontal shutter, as in Specification 1371401. The tens of hours indicator comprises a single shutter 142 controlled by a further cam surface 144 on the cam 56. The shutters appear in two- and seven-segment windows in the front plate (24), Fig. 1 (not shown), of the clock and the windows are illuminated by lamps 42, 44. For setting, a knob 154 projects through the front plate and carries a pinion 158. The knob may be pulled or pushed to engage the pinion with a sprocket 160 or 162 on the cam 52 or 54.