US5180382A
Expired / Lapsed
US
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Bone screw
Assignee: Synthes USA LLC
•
Filing: 1991-12-17
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Granted: 1993-01-19
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Expires: 2011-12-17
Abstract
Abstract A bone screw (1) has a screw head (2), a screw tip (11), and a shaft (5) with a thread (8,14). The threaded segment (6,7) of the shaft (5) has a head-end, essentially cylindrical first shaft section (6) with minor diameter d 1 (16), and a tip-end second shaft segment (7) that is connected with the first shaft segment (6) and which has a smaller minor diameter d 2 (17). The thread (8,14) in the two shaft segments (6,7) has the same pitch (10,12).
Inventors
- 👤 Robert Frigg
- 👤 Stephan Perren
- 👤 Martin Allgower
- 👤 Paul Gisin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:38
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/68; A61B17/84; A61B17/86; A61B17/8625; A61B17/863
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
100 words
A bone screw having a screw head at one end, a tip at the other end and a shaft between the head and tip, said shaft having a first threaded segment at the head end with a major diameter D1 and a minor diameter d 1 and a second threaded segment at the tip end with a major diameter D2 and a minor diameter d 2 , d 2 being less than d 1 , the thread in said segments having the same pitch, and the ratio (d 1 -d 2 )/d 2 being between about 0.004 and about 0.020.
Claim 2
Dependent Claim
100 words
A bone screw having a screw head at one end, a tip at the other end and a shaft between the head and tip, said shaft having a first threaded segment at the head end with a major diameter D1 and a minor diameter d 1 and a second threaded segment at the tip end with a major diameter D2 and a minor diameter d 2 , d 2 being less than d 1 , the thread in said segments having the same pitch, and the ratio (d 1 -d 2 )/d 2 being between about 0.004 and about 0.020.
Claim 3
Dependent Claim
18 words
The bone screw claimed in claim 1, and comprising a transitional segment between the first and second segments.
Claim 4
Dependent Claim
23 words
The bone screw claimed in claim 2, wherein the transitional segment tapers from minor diameter d 1 to minor diameter d 2 .
Claim 5
Dependent Claim
27 words
The bone screw claimed in claim 2 wherein the transitional segment is positioned at a distance from about 15 to about 25 mm. from the screw tip.
Claim 6
Dependent Claim
18 words
The bone screw claimed in claim 4 wherein the distance is between about 18 and about 22 mm.
Claim 7
Dependent Claim
20 words
The bone screw claimed in claim 2 wherein the transition segment is between about 3 and about 7 mm. long.
Claim 8
Dependent Claim
20 words
The bone screw claimed in claim 6 wherein the transitional segment is between about 4 and about 6 mm. long.
Claim 9
Dependent Claim
12 words
The bone screw claimed in claim 1 wherein the thread is self-cutting.
Claim 10
Dependent Claim
33 words
The bone screw claimed in claim 1, wherein the major diameter of the thread of the second shaft segment is smaller than the minor diameter of the thread of the first shaft segment.
Claim 11
Dependent Claim
22 words
The bone screw claimed in claim 1 and comprising a smooth shaft segment between the head end and the first threaded segment.
Claim 12
Dependent Claim
17 words
The bone screw claimed in claim 1 wherein the ratio is between about 0.008 and about 0.012.
Claim 13
Dependent Claim
27 words
The bone screw claimed in claim 1 wherein second shaft segment major thread diameter D 2 corresponds to the diameter D s of the smooth shaft segment.
Claim 14
Dependent Claim
13 words
The bone screw claimed in claim 1 wherein the screw tip is self-cutting.
Claim 15
Dependent Claim
16 words
The bone screw claimed in claim 13 wherein the tip has the form of a trocar.
Claim 16
Dependent Claim
15 words
The bone screw claimed in claim 13 wherein the tip has a radial cutting groove.
Claim 17
Dependent Claim
33 words
The bone screw claimed in claim 1 wherein the ratio between minor diameter dz and the major diameter D 2 of the second threaded shaft segment is between about 0.89 and about 0.95.
Claim 18
Dependent Claim
17 words
The bone screw claimed in claim 16 wherein the ratio is between about 0.91 and about 0.93.
Claim 19
Dependent Claim
24 words
The bone screw claimed in claim 1 wherein the first shaft segment of the shaft is between about 60 and about 80 mm. long.
Claim 20
Dependent Claim
21 words
The bone screw claimed in claim 18 wherein the first shaft segment is between about 65 and about 75 mm. long.
Claim 21
Dependent Claim
26 words
The bone screw claimed in claim 1 wherein the pitch of the thread of the second shaft segment is between about 1.5 and about 2 mm.
Claim 22
Dependent Claim
18 words
The bone screw claimed in claim 20 wherein the pitch is between about 1.7 and about 1.8 mm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-01-19 | 1996-07-20 | 1997-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-01-19 | 2000-07-20 | 2001-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-01-19 | 2004-07-20 | 2005-01-19 | $7700.00 | Window Closed / Lapsed |