US 4,553,942 AGranted

Device including a screw pin and a driven member for screwing the pin into a tooth

AssigneeInstitute Straumann AG

InventorFranz Sutter

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Abstract

An axially extending screw pin to be screwed into a tooth has a threaded part and an engagement part with a slot in one end. The slot extends in the axial direction of the pin toward the threaded part with the axially extending surfaces of the slot converging inwardly toward its base which has a concave, semi-circular surface. The converging sides are convex surfaces defining a quarter arc of a circle. A driven member with an engagement projection at one end shaped complementary to the slot, is disengageably connectible with the screw pin. A gripping member is axially displaceable positioned on the engagement projection end of the driven member. The gripping member is freely rotatable relative to the driven member and has resilient gripping tongues for holding a screw pin relative to the driven member. The driven member is mounted in a drive member so that is can be rotated about its axis. With the screw pin held by the gripping member, the engagement projection is inserted into the slot and threads the screw pin into a tooth. When a stop on the screw pin engages the tooth after it has been driven in for a given depth, the engagement projection backs out of the slot discontinuing the driving action.

Claims24

Dependent claims

An assembly comprising an axially elongated screw pin arranged to be screwed into a tooth and having a first end and a second end spaced apart in the axial direction, said screw pin has an axially extending threaded part extending from the first end toward the second end and an axially extending engagement part extending from the second end toward the threaded part, and a driven member for engaging said engagement part for driving said screw pin about the axis thereof so that said threaded part can be secrewed into a tooth, means for displacing said driven member out of driving engagement with said screw pin when said screw pin is fixed in a tooth, said engagement part has a slot formed axially into and being open at the second end of said screw pin, said driven member comprises an axially extending rod-like member having a first end and a second end, said rod-like member has an axially extending engagement projection at the first end thereof selectively engageable within said slot, an axially extending gripping member having a first end and a second end and said gripping member arranged to laterally enclose an axially extending portion of said rod-like member extending from the first end of said rod-like member, said gripping member has a plurality of axially extending resilient gripping tongues extending from the first end toward the second end thereof for temporarily laterally gripping and holding said engagement part, and said displacing means comprises that at least one of said slot and engagement projection has laterally spaced axially extending surfaces converging inwardly toward one another in the direction toward the respective first end of said screw pin and said rod-like member so that said engagement projection of said rod-like member moves axially out of said slot when said screw pin is fixed in a tooth.

Dependencies are inferred from the claim text.