| 摘要 |
A rotatable arm carrying an operative member is pivoted on a main housing (10) for movement between a rest position and a work position. A rotary shaft (28) is also journaled in the housing and can be driven by a wound spring (34) for rotary movement, which is transformed into a reciprocating, partial rotation of the arm by a linkage comprising meshing gears (18, 22) on the arm and on a fixed axis, and a crank and slotted link (24, 26, 30) between said shaft and the gears. A first and a second locking units (12, 14) are mounted stationarily with respect to the housing, each comprising a spring-biased pawl (40, 42) to engage the arm when it reaches said rest position and said work position, respectively, and each being releasable by an external control. |
