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:
Oct. 22, 1991
Filed:
Oct. 25, 1989
Masuo Ogihara, Yotsukaido, JP;
Hiroyuki Ishida, Yotsukaido, JP;
Shinji Nagaoka, Yotsukaido, JP;
Youichi Seki, Yotsukaido, JP;
Shigeru Tagami, Yotsukaido, JP;
Hiroshi Yamazaki, Yotsukaido, JP;
Nobuo Shinozaki, Yotsukaido, JP;
Seikosha Co., Ltd., , JP;
Abstract
A drive ring drivable by a stepping motor is normally urged by a spring to turn in one direction around a lens aperture. When not in use, the stepping motor is not subjected to the resilient force from the spring since the drive ring is locked against rotation by a ratchet wheel engaged by an engagement lever. The stepping motor is therefore not subjected to undue stresses and is prevented from malfunctioning. Consequently, focusing failures and exposure adjustment failures which could otherwise arise from malfunctioning of the stepping motor are prevented from occurring. In operation, a solenoid is energized to move the engagement lever out of engagement with the ratchet wheel, which is then freed to allow the drive ring to be turned by the stepping motor.