Rotary hand tool

Claim 1

A rotary hand tool comprising an elongated tool shank with a generally cylindrical coupling portion, a longitudinally extending operating handle assembly supporting the tool shank for rotation about the axis of the cylindrical coupling portion and having a longitudinally extending handle member and a coupling mechanism for selectively coupling the handle member to said coupling portion of the tool shank for rotating the tool shank with the handle member, the coupling mechanism comprising a plurality of rolling elements angularly spaced about said generally cylindrical coupling portion of the tool shank and in rolling contact therewith, a longitudinally extending rigid cast housing mounted in the handle member having an axially extending generally polygonal bore, a generally polygonal hard thin metal tubular liner of generally constant wall thickness throughout its extent conforming to and secured within the generally polygonal bore of the cast housing to define a generally polygonal chamber receiving the coupling portion of the tool shank, the generally polygonal bore having a generally polygonal cross-sectional configuration with a plurality of at least as many rounded concave corners as the number of rolling elements and the generally polygonal tubular liner having a corresponding plurality of rounded concave corners defining angularly spaced cavities about the coupling portion of the tool shank loosely receiving individual rolling elements therein and angularly spaced hard metal liner wedging surfaces for each rolling element extending generally tangentially from the respective rounded corner on opposite sides of the respective rolling element for selective engagement with the rolling element for wedging it against the generally cylindrical coupling portion of the tool shank, and rolling elements positioning means comprising a collar surrounding the elongated tool shank coaxially of the cast housing and the tool shank and having an outer end portion at an outer end of the cast housing bore and a tubular portion projecting from the outer end portion inwardly of the bore and the liner, said tubular portion being provided with detent means constantly interlocking the collar to the cast housing for rotating the collar with the housing, said detent means providing alternative first and second detent positions, said collar in its first detent position holding each rolling element relative to the respective liner wedging surfaces for rotating the tool shank with the handle member in a first angular direction only, said collar in its second detent position holding each rolling element relative to the respective liner wedging surfaces for rotating the tool shank with the handle member in the reverse angular direction only.