Patent US4359906A successfully refreshed from Google Patents.
US4359906A
Expired / Lapsed
US
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Device and method for inserting a bone screw
Assignee: Synthes USA LLC
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Filing: 1979-05-18
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Granted: 1982-11-23
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Expires: 1999-05-18
Abstract
Abstract A device for tightening a screw into bone material to a defined torque value M O less than that at which the bone irreversibly deforms including means for measuring the torque, M, necessary to obtain an angular rotation, α, measured from the point where the screw first contacts the underlying material, and determining a value for M O as a function of M/α.
Inventors
- 👤 Jacque R. Cordey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:47
CPC Classifications
B; B25; B25B; B25B23/00; B25B23/14; A; A61; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/88; A61B17/8875
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
198 words
A bone screw driving device adapted for use in orthopedic and traumatologic surgery for tightening a bone screw into bone material to a value M O which is less, by a predetermined factor, than the torque value at which said bone material irreversibly deforms, said device comprising: i. a screw driving tool for engaging said bone screw to rotate and apply tightening torque to said bone screw; ii. means for measuring the amount of tightening torque applied to said bone screw by said screw driving means; iii. means for measuring the angle of rotation of said bone screw; and iv. control means for relating the tightening torque applied to said bone screw and the angle of rotation of said bone screw; for specifying a value for M 0 as a sum of at least one summand which is a constant, independent of torque, and a summand which is proportional to M/α where α is the angle of rotation of the screw measured from the contact of the screw head with an underlying surface, and M is the torque applied as the screw is rotated through α; and for monitoring the applied tightening torque value for M 0 .
Claim 2
Dependent Claim
198 words
A bone screw driving device adapted for use in orthopedic and traumatologic surgery for tightening a bone screw into bone material to a value M O which is less, by a predetermined factor, than the torque value at which said bone material irreversibly deforms, said device comprising: i. a screw driving tool for engaging said bone screw to rotate and apply tightening torque to said bone screw; ii. means for measuring the amount of tightening torque applied to said bone screw by said screw driving means; iii. means for measuring the angle of rotation of said bone screw; and iv. control means for relating the tightening torque applied to said bone screw and the angle of rotation of said bone screw; for specifying a value for M 0 as a sum of at least one summand which is a constant, independent of torque, and a summand which is proportional to M/α where α is the angle of rotation of the screw measured from the contact of the screw head with an underlying surface, and M is the torque applied as the screw is rotated through α; and for monitoring the applied tightening torque value for M 0 .
Claim 3
Dependent Claim
19 words
The device claimed in claim 1 where M 0 also includes a summand proportional to the square of M/α.
Claim 4
Dependent Claim
27 words
The device claimed in claim 2 wherein M 0 is defined as: M.sub.0 =C.sub.0 +C.sub.1 M/α+C.sub.2 (M/α).sup.2 C 0 , C 1 and C 2 being constants.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-22 | 1986-05-24 | 1986-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-22 | 1990-05-24 | 1990-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-22 | 1994-05-24 | 1994-11-23 | $7700.00 | Window Closed / Lapsed |