Patent ID: 8327551

Claim:
An attachment interface for a handheld power tool having an elongated housing and a rotary output shaft with a center axis, the shaft being accessible through a forward end of the housing, said interface comprising: a nose portion on the forward end of the housing, said nose portion having a central opening for accessing the output shaft; a transition portion between the forward end of the housing and said nose portion wherein said transition portion has an inclined outer surface extending radially inwardly toward the output shaft axis; said nose portion having a generally cylindrically shaped wall extending from said transition portion concentrically in the direction of the center axis to a transverse annular flat surface at the front end thereof; a plurality of screw threads formed in an outer surface of said wall configured to have an attachment device with a screw threaded collar mounted on said interface, the collar being screwed onto said nose portion to secure the same thereto; and a first plurality of keys formed in an inner surface of said wall configured to receive have an attachment device with a second plurality of complementary keys that engage at least some of said keys of said inner surface when said attachment device is mounted on said interface, said engaged keys preventing rotation of said attachment device when said attachment device is mounted on said interface.