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US4486177A Expired / Lapsed US ⏱️ 0.0 years remaining

Crown removal tool

Assignee: Individual
•
Filing: 1982-09-24
•
Granted: 1984-12-04
•
Expires: 2002-09-24
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Abstract

Abstract A crown removal tool comprising an elongated hollow cylindrical body having at one end perpendicularly protruding tangs and a slot opening formed therebetween, the tangs adapted to engage one side of a groove formed in a patient's tooth crown, the device additionally comprising an inner rod slidable in the central elongated opening of the hollow cylindrical body, the inner rod having at one end a perpendicularly protruding tang slidably residing in the slot formed between the pair of tangs attached to the hollow cylindrical body, the inner rod tang adapted to engage the other side of the groove formed in a patient's tooth crown, the other end of the inner rod being threaded and having a rotatable nut thereon, the nut adapted to be screwed against the end of the hollow cylindrical body whereby rotation of the nut while engaging the end of the hollow cylindrical body draws the tang attached to the inner rod away from the tangs attached to the hollow cylindrical body. A cap unit resides on the end of the inner body threaded end to limit movement of the threaded nut so that when the threaded nut is against the cap end, the tang of the inner rod aligns with the tangs of the cylindrical hollow body and the tool tangs may be placed in the crown groove whereupon by screwing of the rotatable nut, the tangs are forced apart and the crown fractured which permits its removal.

Inventors

  • 👤 Raymond E. Lekawa

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-26 06:57
CPC Classifications
A; A61; A61C; A61C3/00; A61C3/16; A61C3/162; Y; Y10; Y10T; Y10T29/00; Y10T29/53; Y10T29/53683

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 161 words
A crown removal tool for removing crowns from patient's teeth comprising: an elongated hollow cylindrical body having a first and second end; a pair of transversely protruding spaced apart tangs attached at the first end of said elongated cylindrical body; an elongated slot formed between said spaced apart tangs; an inner rod slidable in said elongated cylindrical body, said inner rod having a first and second end; and a transversely protruding tang attached to the first end of said inner rod, said tang adapted to slidably reside in said elongated slot, said pair of spaced apart tangs of said elongated hollow cylindrical body and said tang of said inner rod adapted to engage opposite sides of a groove formed in the patient's tooth crown where by sliding said inner rod in said hollow cylindrical body, said tangs are separated and thus separate the sides of the groove in the crown causing the crown to fracture and separate from the patient's tooth.
Claim 2
Dependent Claim 161 words
A crown removal tool for removing crowns from patient's teeth comprising: an elongated hollow cylindrical body having a first and second end; a pair of transversely protruding spaced apart tangs attached at the first end of said elongated cylindrical body; an elongated slot formed between said spaced apart tangs; an inner rod slidable in said elongated cylindrical body, said inner rod having a first and second end; and a transversely protruding tang attached to the first end of said inner rod, said tang adapted to slidably reside in said elongated slot, said pair of spaced apart tangs of said elongated hollow cylindrical body and said tang of said inner rod adapted to engage opposite sides of a groove formed in the patient's tooth crown where by sliding said inner rod in said hollow cylindrical body, said tangs are separated and thus separate the sides of the groove in the crown causing the crown to fracture and separate from the patient's tooth.
Claim 3
Dependent Claim 77 words
The crown removal tool as defined in claim 1 wherein said inner rod additionally comprises: a threaded second end; and a rotatable nut thereon, said nut adapted to be screwed upon said inner rod threads against the end of said elongated hollow cylindrical body whereby in doing so, said inner rod moves longitudinally through said elongated cylindrical body and thereby causes the tang attached thereto to move relative to the tangs of the elongated hollow cylindrical body.
Claim 4
Dependent Claim 48 words
The crown removal tool as defined in claim 2 wherein said slidable inner rod additionally comprises: a cap nut residing on said inner rod threaded end next to said rotatable nut whereby one direction of the longitudinal travel of said rotatable nut is limited by said cap nut.
Claim 5
Dependent Claim 46 words
The crown removal tool as defined in claim 3 wherein said elongated cylindrical hollow body transversely protruding tangs include a sharpened edge at the end of said tangs, said sharpened edge adapted to better engage the side of the groove formed in the patient's tooth crown.
Claim 6
Dependent Claim 41 words
The crown removal tool as defined in claim 4 wherein said inner rod transversely protruding tang further comprises: a sharpened edge at the end of said tang adapted to better engage the side of the groove formed in the person's crown.

References Cited (Backward Citations)

US425650A Cited
US606460A Cited
US1349464A Cited
US1357870A Cited
GB400139A Cited
US2220103A Cited
US3426752A Cited
US4179816A Cited
US4196520A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1987-12-04 1988-06-04 1988-12-04 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1991-12-04 1992-06-04 1992-12-04 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1995-12-04 1996-06-04 1996-12-04 $7700.00 Window Closed / Lapsed

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