At normal load, the mechanism is in the position shown, and worm 1 rotates about fixed axis A-A, transmitting rotation to worm wheel 2 about fixed axis B. If there is an overload, the axial force exerted by worm 1 exceeds the resistance of spring 3 and worm 1, together with ring 4, rods 9 and plate 11, is raised so that clutch 5, which drives worm 1, is disengaged. Worm wheel 2 stops. The worm is locked in the disengaged position by vee-block 10 which is turned with lever 6 by spring 7. To reset the device, lever 6 is turned back so that spring 3 can push worm 1 downward, engaging clutch 5 again. The tension of spring 3, which determines the maximum torque that can be transmitted, may be adjusted by nut 8 on the worm shaft.
$2828$WG,SE$