| 摘要 |
1306763 Clocks and watches JUNGHANS GmbH Gebr 19 April 1971 [17 March 1970] 23572/71 Heading G3T A device for holding an escaper or stepping wheel 19 between impulses comprises a magnet arrangement which acts upon the teeth of the wheel or on a part in engagement with the wheel and which consists of a permanent bar magnet 24 surrounded by a cylindrical magnetic field return element 25. Pallet fork 10 which cooperates with stepping wheel 19 is held between impulses in either of its extreme pivotal positions defined by pins 14, 15 by magnet arrangement 24/25. The arrangement 24/25 acts on portions 10d, 10e of the fork 10 which are separated by an air-gap and are provided with ferromagnetic layer 26. Both the bar magnet 24 and the arrangement 24/25 are axially movable to adjust the holding force. The bar magnet may be of platinum cobalt alloy and the element 25 of soft iron. The pallet fork 10 is pivotally mounted on back plate 11 by staff 16 and receives impulses from a balance via a pin engaged in notch 13. The stepping wheel is mounted on an arbor 27 which also carries a ratchet wheel 20 engaged by a lock spring 22. In an alternative embodiment, Fig.3 (not shown), the magnet arrangement (34/35) acts upon the teeth (33a) of a ratchet wheel (3) which is of ferromagnetic material. |
