Sewing machine full and low bobbin indicator
US4212257A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 1979 |
| Grant date | Jul 15, 1980 |
| Priority date | — |
| Expiry date | Jul 5, 1999 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65H2701/31
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A bobbin alarm for a sewing machine which utilizes a light source and a pair of light sensors to provide a warning of low bobbin thread remaining or of a full bobbin condition. The light sensors are arranged with respect to the light source so that one sensor lies substantially on a line from the light source tangent to the hub of the bobbin and the other sensor lies substantially on a line from the light source tangent to the periphery of an imaginary cylinder having the bobbin flanges as the ends thereof. A circuit is provided which is responsive to light stimulation of both sensors (empty bobbin condition) or no stimulation of both sensors (full bobbin condition) to provide a signal to an operator in the form of an illuminated LED.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.