Overspeed brake for a lift car
AssigneeInternational Telephone and Telegraph Corporation
InventorRobert A. Fiss
Life of this patent
Estimating the term…
Abstract
A rotatable sheave is mounted on one end of a platform lift, enabling the sheave to be turned by friction of guide cables as the platform descends. Dogs attached to the sheave extend themselves due to centrifugal force as the platform moves faster. At a specified speed, the governor dogs impact an activating lever which in turn releases a spring loaded retainer rod assembly. The retainer rod assembly then releases spring loaded push rods that engage brake cam dogs on each end of the platform. The brake cam dogs squeeze the guide cables against clamp bodies halting descent of the platform.
Claims8
A braking system in association with a lift platform having a movable lift cable for translating said lift platform and having at least one stationary guide member separate and spaced apart from said lift cable for aligning said lift platform, said system comprising a governor mounted to said lift platform and operatively engaging said guide member and said governor being coupled through a linkage to brake means, said linkage including a plurality of spring loaded elements locked together by pin means and terminating in said brake means, said brake means including a first cam surface element pivotally mounted to said lift platform and operable by said linkage to lock said guide member between said first cam surface and a second cam surface element fixedly mounted to said lift platform, said governor responding to the translation of said lift platform when the speed of said lift platform relative to said guide member exceeds a predetermined maximum, to release said pin means and permit springs associated with said spring loaded elements to apply a force through said linkage to said brake means thereby to rotate said first cam surface element into engagement with said guide means and stop motion of said lift platform.
A braking system for a lift platform having amovable lift cable for translating said lift platform and having at least one stationary guide member separate and spaced apart from said lift cable for aligning said lift platform, said system comprising a governor mounted to said lift platform and operatively engaging said guide member and said governor being coupled by linkage means to brake means, said linkage means including an activating lever and a plurality of spring loaded elements locked together by pin means and terminating in said brake means, said brake means including a first cam surface element pivotally mounted to said lift platform and operable to lock said guide member between itself and a second cam surface element fixedly mounted to said lift platform, said governor responding to the translation of said lift platform when the speed of said lift platform relative to said guide member exceeds a predetermined maximum to operate said activating lever, causing said pin means to release said spring loaded elements and rotate said first cam surface element into engagement with said guide means thereby to operate said brake means to cause said lift platform to stop.
Dependencies are inferred from the claim text.