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. 21, 1984
Filed:
Dec. 31, 1981
Robert R Parker, Wheeling, IL (US);
Rudolph Starai, Arlington Heights, IL (US);
Bell & Howell Company, Chicago, IL (US);
Abstract
Control apparatus is provided for a slide projector to accurately control rotation of a slide tray to predetermined slide positions of the slide tray and to provide integrated control of the slide change function at each slide position. The control apparatus operates in a forced mode between slide positions and operates in a servo mode to accurately position the slide tray at each of the predetermined slide positions. The detection of the slide positions utilizes a circumferential, apertured ring carried on a movable turntable that also carries the slide tray; the ring including a single incremental position aperture corresponding to each of the slide positions. Dual photodetectors are positioned at a sensing station to sense the respective slide position apertures, to provide differential position feedback detection signals in a servo loop, to interrupt the forced mode of operation and for controlling the stopping and positioning of the slide tray to a selected slide position in the servo mode. The control apparatus is operable by a forward/reverse selector switch in a first manual arrangement. Further, the control apparatus is also operable to advance to successive slide positions in response to a control signal derived as a tape advance signal from a cassette tape at variable, preprogrammed intervals. A random access slide projector is provided in another arrangement with the control apparatus being actuated either by decoded slide addresses from a program tape, or by the direct input from a local or remote keyboard.