The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 30, 1987
Filed:
May. 12, 1986
Shigeo Neki, Osaka, JP;
Kenichi Ohara, Osaka, JP;
Nobuho Shibata, Osaka, JP;
Takashi Dohi, Osaka, JP;
Abstract
A sewing machine comprises a multiplier for multiplying an operator-controlled variable reference speed value by a multiplying factor, a tachogenerator for generating speed-related pulses at a rate proportional to the speed of rotation of a motor pulley and an angular position detector for generating a position pulse in response to a predetermined position of an armshaft pulley which is coupled by a belt to the motor pulley. A ratio detector is provided for counting the speed-related pulses present during the interval between successive ones of the position pulse to generate a count as a representation of the diameter of the armshaft pulley and deriving a ratio value between the count and a value representative of the diameter of the motor pulley. The ratio value is applied to the multiplier as the multiplying factor to alter the reference speed value. A speed control circuit is responsive to the speed-related pulses for deriving an actual motor speed value and controls the speed of the motor in accordance with a difference between the actual motor speed value and the altered reference speed value.