| 摘要 |
PURPOSE:To advance exactly a push-hand without requiring large torque for a driving part, and also to execute exactly zero-resetting, by using a differential gear mechanism. CONSTITUTION:A rotary disk 30 of a watthour meter transfers a rotation being proportional to electric energy to be used, to a center shaft 61 through differential gear mechanisms 39, 47, and advances a demand pointer 19 by a push-hand 62. Loose gears 59, 60 are held in a nonrotating state as shown by a full line by detaining pawls 72, 73. Subsequently, when reaching a prescribed demand time limit, the detaining pawls 71-73 are switched to a state shown by a dotted line, respectively, by a time limiting device, the loose gears 59, 60 become freely rotatable, a spur gear 46 becomes a non-rotating state, magnets 54, 55 are magnetized each other and are magnetically coupled, the center shaft 61 is rotated in the opposite direction by a synchronous motor 57, and the push-hand 62 is reset immediately to a zero point. When the detaining pawls 71-73 are reset to a state of the full line again, the demand pointer 19 indicates the maximum value in mean electric power in each time limit by advancing the demand pointer 19 only when electric energy to be used in the same time limit is larger than the previous time limit. |
