Device for determining the angular position of the drive shaft in a sewing machine

US4988865A · kind A · utility

Assignee

• Frankl & Kirchner GmbH & Co KG Fabrik für Elektromotoren u. elektrische Apparate · DE

Inventors

• Thomas Schmidt · Plankstadt, DE
• Bernd Olbrich · Ketsch, DE
• Gerd Nohl · Wiesloch, DE
• Gustav Rohr · Heidelberg, DE

Key dates

• Filing date: Mar 17, 1989
• Grant date: Jan 29, 1991
• Expiry date: Mar 17, 2009

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/2455
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a position indicating device, especially for an industrial sewing machine, with a slotted wheel (3) and a first track (6) of slots (4) having, e.g., 512 slots (4), to permit a null-point synchronization over a relatively small range of rotational angles, and the establishment of definite angular positions, a second track (8) with slots (7) of various widths is provided. The first track (6) of slots (4) is associated with two light barrier arrangements comprising emitters (11a, 11b), receivers (12a, 12b), and masks (13a, 13b) while the second track (8) is associated with one light barrier arrangement. Evaluating systems are connected to the receivers (12) so that, on the basis of the number of slots (4) of the first track (6), the size of the slots (7) passing in each case and corresponding approximately to a multiple of the slot width may be determined through evaluating systems (14, 28) connected to the output, and in this manner to define the rotary angle position.