| 摘要 |
<p>A timepiece, with a clockwork driven by a stepping motor, has a clockwork-supporting structure with front and rear uprights, generally of hourglass shape, each constituted by a pair of mirror-symmetrical coplanar strips defining its contour, the front upright being framed by an annular dial swept by the minute and hour hands the gears of the clockwork are visible from all sides. The supporting structure with the dial is mounted on a platform carried by two columns above a base which contains the motor, its power supply and a tone generator controlled by the clockwork to emit acoustic time signals on the hour and possibly also on the half and quarter hours; a torsion pendulum without time-keeping function is sus0 between the columns. Most of the shafts of the clockwork lie in a vertical plane of symmetry also containing the axis of the nested hour, minute and seconds shafts disposed at the center of the dial ring. An ancillary shaft offset from that plane has a pinion in mesh with a gear included in the step-down transmission between the minute and hour shafts so as to rotate in step with the minute hand at one revolution per hour; this ancillary shaft carries a resetting knob and two cam disks, one of them controlling a switch for the periodic actuation of the tone generator while the other causes a resynchronization of that tone generator every 12 hours. The resetting knob is provided with a one-way coupling to prevent reverse rotation of the control cams; the seconds shaft carries an impeller for the torsion pendulum.</p> |
