Patent ID: 6070641
Filing Date: 2000-06-06
Classification: E05D,E05Y,E06B,Y10T

Abstract:
Automatic braking mechanism for a rolling door system having a support shaft for selectively rolling up or lowering a rolling door formed of a series of connected slats, a driven wheel on the support shaft, a motor drive for driving a drive wheel and a continuous loop drive coupling said drive and driven wheels and normally moving along a predetermined path prior to failure when said loop is under tension in a drive plane generally normal to said support shaft, said braking mechanism comprising an elongate sensing arm pivotally mounted at one end and carrying a follower at the other end normally indirect contact with said loop drive, said sensing arm being movable within a plane substantially parallel with said drive plane to arrange said follower in said drive plane for movements from one side of said predetermined path to at least partially bridge or cross said predetermined path to the other side thereof, an elongate actuator arm pivotally mounted for sharing common angular movements with said elongate sensing arm about a common pivot point; stop means mounted on said actuator arm for sharing pivotal movements with said actuator arm for movements between a normal mode disengaged position in which said stop means clears said drive wheel to permit rotation thereof when said follower engages said loop drive while said loop drive is under tension and a failure mode position in which said stop means engages said driven wheel to prevent rotation thereof when said follower bridges said predetermined path; and biasing means for normally urging said actuator arm to move to a failure mode position, whereby said loop drive maintains said arms in said normal positions prior to failure.