Patent ID: 7111527

Claim:
A selective one-way screwdriver comprising: a handle ( 10 ); at least one head ( 11 ) at an end of the handle ( 10 ), the head ( 11 ) defining a space ( 12 ), a cavity ( 15 ) in the top, a recess ( 17 ) eccentrically in the floor of the cavity ( 15 ), and a channel ( 18 ) between the space ( 12 ); and a selective one-way driving device ( 2 ) comprising: a spring-biased detent ( 19 ) disposed in the recess ( 17 ) of the head ( 11 ); a switch ( 20 ) disposed in the cavity ( 15 ), the switch ( 20 ) comprising three recesses ( 22 ) selective one of which receives the spring-biased detent ( 19 ) in order to position the switch ( 20 ); a pawl device ( 25 ; 26 ; 27 ) movable in the channel ( 18 ) under the control of the switch ( 20 ); and an annular gear ( 30 ) disposed in the space ( 12 ), the annular gear ( 30 ) comprising a toothed wheel portion ( 31 ) on the external side for engagement with the pawl device ( 25 ; 26 ; 27 ) and a recess ( 37 ) in an end for receiving a bit ( 40 ) so that a large torque can easily be generated.