GB249078A - Improvements in or relating to electrically driven timepieces - Google Patents

Abstract

249,078. Juillerat, M. A. March 16, 1925, [Convention date]. Electric clocks; driving -mechanism, main spring.-An electrically-driven watch or clock having self-contained means for re-energizing the main spring is provided with means for maintaining the drive during such re-energization. An electromagnet 10 has a U-shaped yoke 11 and a winding 13 connected to a negative terminal 27 and to a terminal 24 connected in series with a positive terminal 20. The armature 14 is pivoted to the lower limb of the yoke and carries a. member 17, 18. Fixed to the same limb is a blade spring 15 constituting the main spring and this normally bears to the left against the head 16 of a screw carried in the member 17, which also supports a leaf spring 22 coacting with the contact 20. The member 18 carries a pawl 35 co-operating with a ratchet wheel 30 of 60 teeth. This wheel is mounted loosely on the minute wheel arbor 31 and has a pin 32 coacting with a spring 33 on the arbor 31 and with a pin 34 on a wheel of the time-train which has an escapement, not shown. On the opposite side the wheel 30 coacts with a pawl 36 on a blade 25 so that when this pawl slips off the point of a tooth the blade 25 makes contact suddenly with the terminal 24. The device is arranged to energize the spring 15' once a minute in the following manner. In the position shown the magnet has been energized at the end of a minute and has attracted the armature breaking contact at 20 and moving the pawl 35 behind the next tooth. The spring 15, re-energized, now pulls the pawl 35 to the left, slightly winding up initially the auxiliary spring 33 and driving the time train. This continues until contact is again made at 20 and in the meantime pawl 36 rides up a tooth breaking contact at 24. Near the end of the next minute contact is made at 20 as the spring 15 reaches the limit of its travel and shortly afterwards the pawl 36 slips off its tooth and contact 24 being suddenly closed in series with contact 20, the magnet is energized to re-energize the main spring. During such reenergization of the main spring the pawl 36 prevents retrograde movement of the wheel 30 and the initial compression of spring 33 is used to continue the drive of the time train. Specification 16814/04 is referred to. The Specification as open to inspection under Sect. 91 (3) (a) also describes and illustrates an adjustable stop for limiting the travel of the member 18. This subject-matter does not appear in the Specification as accepted.