Anchor for dental prostheses

Claim 1

An anchor for a dental prostheses comprising: a housing having an external threaded portion adapted to be threaded in a dental prostheses; said housing having an internal bore terminating in an end wall having a central opening defining an internal annular shoulder between said bore and said opening, a plunger mounted within said housing for axial movement relative thereto into an extended position and a retracted position, said plunger having an inner body portion within said housing and an outer body portion disposed in said opening, a spring biasing said plunger to said extended position whereby said outer body portion projects through said opening axially outwardly from said housing, said plunger having an annular shoulder between said inner and outer body portions engagable with said housing shoulder for limiting movement of said plunger in an outward direction to said extended position, a plug mounted within said bore at the end opposite said end wall, said plug having an inner abutment face limiting movement of said plunger in a reverse direction to said retracted position, the distance between the opposing faces of said plug and the inner end of said plunger in its extended position being approximately equal to the distance that said outer body portion projects beyond the end of said housing thereby preventing retraction of the outer end of said outer portion inwardly past said housing end; said plug having an annular recess for receiving one end of said spring for properly positioning said spring within said housing; said spring serving as a guide for said inner body portion of said plunger.