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:
Feb. 07, 1989
Filed:
Oct. 07, 1987
Paul A Sepesy, Youngstown, OH (US);
Commercial Shearing, Inc., Youngstown, OH (US);
Abstract
The present invention relates to a motor control circuit for a stepper motor which causes a motor shaft to oscillate between an incremental rotational position nearest above and nearest below a commanded average rotational position identified by an electrical command signal. A clock is provided for sending periodic clock signal pulses to the control circuit. An up/down counter is connected to the clock for counting clock pulses on each clock cycle and for providing an output signal in the form of a binary representation of total clock pulses. A comparing circuit electrically connected to the up/down counter is used to control an up/down direction of the up/down counter before each clock signal pulse so that the up/down counter causes the motor shaft to rotate to a position nearest beyond the commanded shaft position and to thereafter oscillate between an incremental count nearest above and an incremental count nearest below the commanded average rotational position. The invention provides the benefit of greater average shaft position resolution and, additionally, because oscillation is provided, the present invention is particularly useful in the electrical positioning of valve spools or variable displacement pumps in a manner which reduces the possibility of spool sticking.