Thread trimmer system for in-line chain stitch sewing machine
US4879960A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 22, 1988 |
| Grant date | Nov 14, 1989 |
| Priority date | — |
| Expiry date | Jul 22, 2008 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD05B65/02
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Apparatus and method for severing the needle and looper threads of a chain stitch formed by a sewing machine having an in-line looper system. The sewing machine has a needle plate and a needle carrying the needle thread through the material and the needle plate to form a needle loop of needle thread therebelow that has a needle side running to the needle. The apparatus comprises a stationary knife, a spring positioned below the stationary knife and biased in a direction toward the stationary knife, and a movable knife slidably mounted between the stationary knife and the spring which yieldingly urges the movable knife thereagainst. The movable knife has one penetrating end with a pair of axially offset barbs, a lagging barb and a leading barb closer to the penetrating end of the movable knife than the lagging barb. These three elements cooperate to hook and sever the needle side of the needle loop and the looper thread below the needle plate and prepare the looper thread for the next stitch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.