| 摘要 |
A MATERIAL HOIST THAT PREVENTS LIFTED LOADS WITHIN A VERTICAL MAST FROM FREE-FALLING WHEN A LOSS OF LIFTING FORCE OCCURS. A LOSS OF THE LIFTING FORCE MAY OCCUR IN SEVERAL WAYS, FOR EXAMPLE IF A LIFTING CABLE WERE TO BREAK, THE BRAKES WERE TO FAIL ON A WINCH, OR THE LIFTING MECHANISM ITSELF WERE TO FAIL. UNDER NORMAL LIFTING CONDITIONS, THE BRAKE ASSEMBLY OF THE INVENTION IS SUBJECT TO AN UPWARD LIFTING FORCE FROM THE HOIST AND A DOWNWARD PULLING FORCE FROM A SUSPENDED LOAD. IF THE LIFTING FORCE SHOULD SUDDENLY CEASE, THE BRAKE ASSEMBLY WILL ROTATABLY ACTIVE A SET OF BRAKE ROLLERS TO CLAMP ONTO THE VERTICAL MAST TO STOP THE FREE-FALL DESCEND OF THE LOAD.
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