Rotatable socket for a dental handpiece

Claim 1

In a rotatable socket for supporting a tool for rotation in a head housing of a dental hand piece, said socket including a hollow cylindrical shaft having a bore for receiving a tool from one end and having a dog for engagement with a flattened surface on a shank of the tool for transmission of torque therebetween, said socket having a catch means comprising of at least one support element extending parallel to the axis of said hollow cylindrical shaft and having a catch nose extending radially inward for engagement in an annular groove in the shank of the tool disposed in said hollow cylindrical shaft, said catch means including means biasing said catch nose radially inward, said catch means including a thumb actuated purchase disposed on the head housing for releasing each of the catch noses upon actuation to allow disengagement of the tool from said socket, the improvements comprising the hollow cylindrical shaft containing an inner recess adjacent said bore for accepting the catch means, said recess receiving each support element and providing space adjacent the catch nose to enable radial outward movement of the catch nose to a position to enable disengagement of the catch nose from the tool, each support element being disposed in said recess with a free end being adjacent the other end of the shaft and a pressure element being disposed adjacent said other end of the shaft and in alignment with and disengaged from each free end, said purchase being mounted on the housing free of contact with all rotatable parts and adjacent the pressure element for relative movement so that when actuated the purchase urges the pressure element into engagement with each free end of the support element to urge each of the catch noses radially outward to a position to release a tool in said socket.