US4917031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cloth-pattern sensing device for a sewing machine
Assignee: Brother Industries Ltd
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Filing: 1988-12-21
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Granted: 1990-04-17
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Expires: 2008-12-21
Abstract
Abstract A device for performing an initial setting of a photosensor of a sewing machine including a light-emitting element and a light-receiving element. The device adjusts the strength of light emitted by the light-emitting element so that the output of the light-receiving element responding to the emitted light falls within a preset normal range. Thus the output from the light-receiving element is normalized and the photo-sensor can correctly discriminate various levels of reflectance, i.e., between a pattern signal and a cloth-edge signal, or among pattern signals of various brightnesses.
Inventors
- 👤 Hirosumi Itoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:52
CPC Classifications
D; D05; D05B; D05B35/00; D05B35/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
155 words
A cloth pattern sensing device for a sewing machine, the sensing device comprising: a light-emitting element for emitting light on a cloth; a light-receiving element for receiving the light influenced by patterns of the cloth and for generating an output corresponding to an intensity of the received light; a standard reflection surface for reflecting the light from the light-emitting element to the light receiving element with a fixed reflectance; memory means for storing preset upper and lower limit output values for the light-receiving element corresponding the light reflected by the standard reflection surface, the limit values being determined so that all light received by the light-receiving element falls within its normal operable range; and an emitter controller for controlling a strength of light emitted from the light emitting element so that the light-receiving element, in response to the light reflected by the standard reflection surface, generates an output within the upper and lower limit values.
Claim 2
Dependent Claim
155 words
A cloth pattern sensing device for a sewing machine, the sensing device comprising: a light-emitting element for emitting light on a cloth; a light-receiving element for receiving the light influenced by patterns of the cloth and for generating an output corresponding to an intensity of the received light; a standard reflection surface for reflecting the light from the light-emitting element to the light receiving element with a fixed reflectance; memory means for storing preset upper and lower limit output values for the light-receiving element corresponding the light reflected by the standard reflection surface, the limit values being determined so that all light received by the light-receiving element falls within its normal operable range; and an emitter controller for controlling a strength of light emitted from the light emitting element so that the light-receiving element, in response to the light reflected by the standard reflection surface, generates an output within the upper and lower limit values.
Claim 3
Dependent Claim
71 words
The cloth pattern sensing device according to claim 1, wherein the emitter controller comprises: means for comparing the output of the light-receiving element with the upper and lower limit values; means for decreasing the strength of light by a preset amount when the output exceeds the upper limit value; and means for increasing the strength of light by a preset amount when the output is lower than the lower limit value.
Claim 4
Dependent Claim
62 words
The cloth pattern sensing device according to claim 2, wherein: the light-emitting element comprises a comparator, a triangular-wave generator connected to an input terminal of the comparator, and a duty-controlled emitter driver connected to an output terminal of the comparator; and the increasing means and the decreasing means respectively increase and decrease voltage levels input into another input terminal of the comparator.
Claim 5
Dependent Claim
39 words
The cloth pattern sensing device according to claim 1, wherein the light-emitting element generates a pattern signal when a cloth is present at a sensing point, and a cloth-edge signal when no cloth is present at the sensing point.
Claim 6
Dependent Claim
42 words
The cloth pattern sensing device according to claim 1, wherein the standard reflection surface is a cloth-guide plate having a reflectance higher than a brightest cloth which reflects light from the light-emitting element to the light-receiving element when no cloth is present.
Claim 7
Dependent Claim
38 words
The cloth pattern sensing device according to claim 5, wherein the light-receiving element generates a pattern signal in receiving the light reflected from the cloth, and a cloth-edge signal in receiving the light reflected from the cloth-guide plate.
Claim 8
Dependent Claim
30 words
The cloth pattern sensing device according to claim 4, wherein the emitter controller controls the light-emitting element based on the value of the cloth-edge signal generated by the light-receiving element.
Claim 9
Dependent Claim
30 words
The cloth pattern sensing device according to claim 6, wherein the emitter controller controls the light-emitting element based on the value of the cloth-edge signal generated by the light-receiving element.
Claim 10
Dependent Claim
30 words
The cloth pattern sensing device according to claim 1, wherein a control routine for controlling the light-emitting element is executed when the power to the sewing machine is turned on.
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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) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |