| 摘要 |
A stapler ( 1 ) for stapling a workpiece ( 5 ), especially a sheaf of papers, which stapler comprises a base part ( 2 ) and a stapling head ( 3 ) which are connected together by a connecting means ( 4 ) in such a way that they can move towards and away from one another in a reciprocating stapling movement (P) which has a first turning point (FIG. 1 ) and a second turning point (FIG. 3 ), which stapling head accommodates staples ( 14 ) and a driver ( 7 ) which is supported for sliding in the direction of the stapling movement and which during the course of the stapling movement drives a staple into the workpiece which is to be stapled, and said stapler also comprises a drive means ( 13 ) which, in the course of a driving stroke (N) which forms part of the stapling movement, starting from a point at which the stapling head and the base part are at a distance from one another, drives the stapling head and the base part towards one another to the second turning point (FIG. 3 ) at which the stapling head and the base part are at their shortest distance from one another and are in clamping contact with the workpiece, and thereafter drives the driver to said second turning point, during which driving a staple is driven into the workpiece, after which the parts perform a return stroke (R) which brings them back to the starting point, wherein the drive means also comprises an activating arrangement ( 16 ) which is in connection via a first coupling ( 19 ) to the stapling head and the driver and via a second coupling ( 28 ) to the base part in such a way that during the stapling movement the activating arrangement varies the distance between the first and second couplings from a first extreme position in which the stapler is at the first turning point of the stapling movement to an opposite second extreme position in which the stapler is at the second turning point of the stapling movement wherein at least one of the couplings ( 19, 28 ) is releasable and is so arranged that in the course of the driving stroke (N) it is brought to a released position (FIG. 8 ) in which it loses its effective connection in the stapling movement direction (P) if the driving stroke (N) can not reach the second turning point (FIG. 3 ).
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