U.S. patents available from 1976 to present.
U.S. patent applications available from 2005 to present.

Fail-safe device for raising/lowering articles

Patent 6742770 Issued on June 1, 2004. Estimated Expiration Date: Icon_subject May 1, 2021. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Patent References

152635

669443

674673

723231

803274

817039

826727

829320

896646

916091

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Inventor

Application

No. 09846831 filed on 05/01/2001

US Classes:

254/391, With mechanism for retarding or preventing cable movement or element rotation254/405, With block for element and portion thereof repositionable for insertion or removal of cable or for exposure of element248/125.2, Bracket moved by mechanical operator (e.g., spring, threaded shaft, pulley and rope)248/321, Clutch type248/322, Hook type24/134KBCam engaging or disengaging

Examiners

Primary: Marcelo, Emmanuel M.

International Class

B66D 384

Abstract

A failsafe device for raising/lowering articles includes a frame and a fastener for attaching the frame to a ceiling or wall to elevated an article above the floor. A pulley or sheave is mounted on the frame about a substantially horizontal axis when the frame is mounted on the ceiling or wall. A cable is entrained over the pulley and has a substantially vertical lifting cable portion attachable to the article to the lifted and a substantially vertical pulling cable portion arranged to be pulled downwardly by a user to elevate the article and raised upwardly to lower the article. A cam is mounted on the frame on one side of the pulling cable portion and has a cable engaging surface. The cam is movable between a cable releasing position and a cable locking position, the cable engaging surface including a first engaging portion normally spaced a fixed distance from the pulling cable portion to form a clearance gap in the cable releasing position and a second engaging portion bridging the clearance gap a distance equal to least the fixed distance for substantially instantaneously arresting the cable and preventing movement of the pulling cable portion upwardly toward the pulley and corresponding downward movement of the article. A pusher is mounted on the frame for always applying a force on the pulling cable portion in the direction of the cam for urging it across the clearance gap into contact with the first engaging portion only when tension in the pulling cable portion is decreased relative to the tension in the lifting cable portion, continued contact between the pulling cable portion causing the second engaging portion to bridge the clearance gap as it moves from the releasing to the locking positions until a tension is applied by the user to the pulling cable portion with a force that substantially corresponds to the weight of the article.

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