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:
Mar. 24, 1981
Filed:
Jan. 26, 1979
Sony Corporation, Tokyo, JP;
Abstract
A single pickup head generates an alternating signal proportional to the rotational speed of a DC motor which can be rotated in either of two directions, and such alternating signal is employed by speed and/or phase control circuits to control the motor speed relative to a reference speed in a selected one of the two directions. An overspeed sensing circuit detects speed runaway, which can occur when the motor is rapidly rotated in the direction opposite to the selected direction, and the overspeed sensing circuit then interrupts the motor drive voltage until the motor speed decreases to below its normal speed. At and below normal speed in the undesired direction, the normal torque acts in the selected direction to rapidly reverse the direction and to accelerate the motor to normal speed in the selected direction.