GB161184A - Apparatus for intermittently operating an index moving over an auxiliary circle of hours arranged on an ordinary horary dial - Google Patents

Abstract

161,184. Soc. Anon. d"Horlogerie et Bijouterie de GenÞve. April 5, 1920, [Convention date]. Dials; motionwork. - In clocks, watches, and other time indicators an additional index is arranged in connection with an auxiliary set of hour numerals and is operated to rotate at the same speed as the ordinary hour index hand during twelve hours and to be staticnary during the succeeding twelve hours, so as to indicate twenty-four hour time. A wheel b, Figs. 3 and 5, having a projection b<1> is geared to the hour pinion so as to rotate once in twenty-four hours and a second wheel c gearing with the pinion of the index v is arranged to be intermittently driven by the wheel b. The wheel c is provided with two depressed tongues c<1>, Fig. 4, having upturned ends c<2>. The clock plate is provided with a semicircular groove or slot so that one of the tongues c<1> is in the depressed state and so withdraws the end c<2> out of engagement with the projection b<1> thereby ceasing to drive the wheel c and consequently the index v. At the end of half a revolution, i.e. twelve hours, the projection b<1> comes into contact with the other upturned end c<2>, the tongue c<1> being pressed into the elevated position bv the clock plate and causing the wheel c to be driven the tongue c<1> falling into the semicircular groove in the clock plate at the end of twelve hours. The index v completes a revolution at every half revolution of the wheel c. In another arrangement, a wheel b, Figs. 6 and 7, revolving once every twenty-four hours carries a pawl b<1> which when not riding on a fixed cam r encounters a pin c' on a wheel c and drives it. At the end of half a revolution of the wheel b the pawl b<1> rides on the cam r and is therefore disengaged from the pin c<1> causing the wheel to remain stationary for half a revolution of the wheel b. The wheel c drives the index pinion d.