US3702102A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selectable bobbin thread tensions
Assignee: Singer Co
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Filing: 1971-07-19
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Granted: 1972-11-07
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Expires: 1991-07-19
Abstract
Abstract A method and apparatus for obtaining a variety of selectable bobbin thread tensions in a lockstitch sewing machine wherein bobbin thread tension is achieved by resisting bobbin rotation by pressing a bobbin hold down arm against an annular protuberance on a flange of the bobbin and concentric with the center of rotation of the bobbin, replacing the bobbin with one similarly constructed but having its protuberance at a suitable different radius when a change in bobbin tension is required.
Inventors
- 👤 Donald R Davidson
- 👤 Edmund B Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:38
CPC Classifications
D; D05; D05B; D05B63/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
89 words
In a lockstitch sewing machine wherein bobbin thread tension is achieved by resisting bobbin rotation, selectable bobbin thread tensioning means comprising a bobbin case adapted to support a flanged thread carrying bobbin for rotation therein, means carried on said bobbin case to retain said bobbin in said bobbin case, means associated with said retaining means for applying a rotation resisting force to said bobbin in said bobbin case at selectable radii, whereby rotation of the bobbin may be impeded a selectable amount to produce a selectable bobbin thread tension.
Claim 2
Dependent Claim
89 words
In a lockstitch sewing machine wherein bobbin thread tension is achieved by resisting bobbin rotation, selectable bobbin thread tensioning means comprising a bobbin case adapted to support a flanged thread carrying bobbin for rotation therein, means carried on said bobbin case to retain said bobbin in said bobbin case, means associated with said retaining means for applying a rotation resisting force to said bobbin in said bobbin case at selectable radii, whereby rotation of the bobbin may be impeded a selectable amount to produce a selectable bobbin thread tension.
Claim 3
Dependent Claim
119 words
Selectable bobbin thread tensioning means as set forth in claim 1 in which said means to retain said bobbin includes a lever arm carried by the bobbin case, and a resilient member to urge said lever arm against said bobbin; said bobbin being one of a set of bobbins each having a flange formed with a raised annular protuberance concentric to the bobbin axis of rotation and at differing radii for each bobbin in said set, said lever arm and said resilient member cooperating to frictionally engage said raised annular protuberance on said flange of any selected bobbin of the set of bobbins, whereby said differing radii for said raised annular protuberances will result in differing bobbin thread tension.
Claim 4
Dependent Claim
93 words
Selectable bobbin thread tensioning means as set forth in claim 1 in which said means to retain said bobbin includes a lever arm carried by said bobbin case, and a resilient member to urge said lever arm against said bobbin; and said means for applying a normal force to said bobbin in said bobbin case at selectable radii includes a friction shoe means slidable on said lever arm to allow for selecting radius of force application to the bobbin whereby selectable resistance to bobbin rotation and thereby bobbin thread tension may be obtained.
References Cited (Backward Citations)
US875603A
Cited
US3467068A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-07 | 1976-05-08 | 1976-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-07 | 1980-05-08 | 1980-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-07 | 1984-05-08 | 1984-11-07 | $7700.00 | Window Closed / Lapsed |