Device for stopping the drive of a sewing machine in the case of a thread disturbance

US5159890A · kind A · utility

Assignee

• G.M. Pfaff Aktiengesellschaft · DE

Inventors

• Kurt Arnold · Kaiserslautern, DE
• Peter Liell · Stelzenberg, DE

Key dates

• Filing date: Jul 30, 1991
• Grant date: Nov 3, 1992
• Expiry date: Jul 30, 2011

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D05B73/12
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

A sewing machine is provided with a device for stopping the drive in the case of a thread disturbance. The device has a light source, a first light guide device for transmitting the light beams to the monitoring point, a second light guide device, via which a signal can be sent to a receiver in the absence of thread at the monitoring point, and a control unit for signal evaluation and to report a thread disturbance, even in the case of maximum deflection of the thread at right angles to the pull-off direction, only when a thread disturbance does really exist. To achieve this, the first light guide device is designed, on its side facing the thread, in a plane perpendicular to the thread pull-off direction, with a radiation outlet which extends preferably in the horizontal direction. The first light guide device causes light beams to be sent over the maximum range of movement of the thread at equal radiation intensity over an entire radiation cross section. A radiation inlet of the second light guide device, whose radiation inlet is intended to receive the light beams passing through the maximum range of movement of the thread at right angles to the pull-off direction after the threa…