Reduction gear of electronic wristwatch with stepping motor and sweep second hand

摘要

PCT No. PCT/SU79/00028 Sec. 371 Date Apr. 11, 1980 Sec. 102(e) Date Apr. 10, 1980 PCT Filed Apr. 27, 1979 PCT Pub. No. WO80/00380 PCT Pub. Date Mar. 6, 1980.The reduction gear of an electronic wristwatch comprises three concentric output shafts adapted to be rotated at different speeds and operatively connected with each other and with the shaft of a stepping motor through gear wheels. A shaft making one revolution per hour has mounted thereon a friction wheel and a bearing means made in the form of a supporting bush press fitted in a bore of the plate of the wristwatch. The bush is mounted so that a portion thereof projects from the plate toward the bridge of the wristwatch, coordinated with respect to the plate and attached thereto by threaded means. The shaft passes freely through a bore in the supporting bush and is restricted from an unlimited axial displacement in one direction by an end face of the supporting bush, and in the other direction by the end face of that pinion which is mounted on the shaft with interference fit. The reduction gear of an electronic wristwatch can be used by the watch-making industry in the production of quartz wristwatches having a stepping motor, and of like timepieces.