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:
Apr. 17, 1990
Filed:
Sep. 29, 1989
Volker Weinert, Taufkirchen, DE;
AGFA-Gevaert Aktiengesellschaft, Leverkusen, DE;
Abstract
A reel for webs of photographic material can be driven clockwise and counterclockwise by a reversible d-c motor through the medium of the output shaft of the motor, a second shaft which is coaxial with the output shaft and serves to rotate the reel, and a torsion spring between the shafts. Each shaft carries a disc-shaped polarizing filter, and both filters extend across the path of propagation of radiation from the radiation source to the transducer of an analog optoelectronic detector. The characteristics of signals which are generated by the transducer vary as a function of the extent of angular displacement of the shafts and filters relative to each other. Such signals are transmitted to an evaluating circuit which controls the flow of energy to the motor as a function of deviations of the characteristics of transmitted signals from the characteristics of a reference signal. The purpose of the evaluating circuit is to ensure the transmission of constant torque to the second shaft irrespective of the direction of rotation of the motor.