US4214542A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low bobbin thread detection system including photodetector holder shielded with plastic lens
Assignee: Retail Holding NV
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Filing: 1979-06-04
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Granted: 1980-07-29
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Expires: 1999-06-04
Abstract
Abstract A holder containing the light detector of the low bobbin thread detection system of a sewing machine and including a light admitting aperture through which light may pass to a photodetector is provided with a plastic tubular collar which extends over the aperture and serves both as a shield to keep lint out of the aperture and as a lens to focus light on a light sensitive surface in the photodetector.
Inventors
- 👤 Charles R. Odermann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:20
CPC Classifications
D; D05; D05B; D05B59/00; D05B59/02; B; B65; B65H; B65H63/00; B65H63/08; B65H63/086; B65H2701/00; B65H2701/30; B65H2701/31
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
97 words
In a low bobbin thread detection system for a sewing machine including a light source, a photodetector to receive light from said source when bobbin thread is about to be depleted, and a warning device operable by the photodetector, the combination comprising a holder in which the photodetector is situated and which has an aperture therein to permit light from the light source to pass to the photodetector, and a plastic collar on the holder extending over the aperture and shaped opposite the aperture as a lens to focus light from the light source on the photodetector.
Claim 2
Dependent Claim
97 words
In a low bobbin thread detection system for a sewing machine including a light source, a photodetector to receive light from said source when bobbin thread is about to be depleted, and a warning device operable by the photodetector, the combination comprising a holder in which the photodetector is situated and which has an aperture therein to permit light from the light source to pass to the photodetector, and a plastic collar on the holder extending over the aperture and shaped opposite the aperture as a lens to focus light from the light source on the photodetector.
Claim 3
Dependent Claim
18 words
The combination of claim 1 wherein the plastic collar is shaped as a plano-convex lens opposite the aperture.
Claim 4
Dependent Claim
23 words
The combination of claim 1 wherein the plastic collar is stretched over the holder and shaped thereby as a lens opposite the aperture.
Claim 5
Dependent Claim
19 words
The combination of claim 3 wherein the collar is formed from a section of cylindrical tubing of uniform thickness.
Claim 6
Dependent Claim
41 words
The combination of claim 4 wherein the holder includes a planar surface with the aperture extending therethrough, and the stretched collar extends across the planar surface and around a portion of the holder to form a plano-convex lens opposite the aperture.
Claim 7
Dependent Claim
20 words
The combination of claim 1 wherein the lens has a focal point at a light sensitive surface in the photodetector.
Claim 8
Dependent Claim
25 words
The combination of claim 1 wherein the collar is stretched over the holder and a tight frictional bond is thereby established between collar and holder.
Claim 9
Dependent Claim
16 words
The combination of claim 1 wherein the collar is formed from a section of polyurethane tubing.
Claim 10
Independent Claim
71 words
The method of forming a lens over the light admitting aperture of the photodetector holder of a low bobbin detector system for a sewing machine comprising the steps of forming a planar surface on the holder to include the aperture, forming a collar from plastic tubing of uniform cross-section, and stretching said collar around a portion of the holder including the planar surface to form a plano-convex lens opposite the aperture.
Claim 11
Independent Claim
71 words
The method of forming a lens over the light admitting aperture of the photodetector holder of a low bobbin detector system for a sewing machine comprising the steps of forming a planar surface on the holder to include the aperture, forming a collar from plastic tubing of uniform cross-section, and stretching said collar around a portion of the holder including the planar surface to form a plano-convex lens opposite the aperture.
References Cited (Backward Citations)
US3599586A
Cited
US3738296A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-07-29 | 1984-01-28 | 1984-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-29 | 1988-01-28 | 1988-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-29 | 1992-01-28 | 1992-07-29 | $7700.00 | Window Closed / Lapsed |