| 摘要 |
<p>An emergency brake for checking the accidental fall of an industrial door or shutter which is slidable vertically and rollable on a roller, directly or by means of belts, includes a fixed body (1), a hub (5) rotatable in the fixed body and connected to the roller of the door. A wheel (11) carrying velocity sensors (15) and a wheel (12) with ratchet toothing (17) are clamped frictionally to the hub (5). An intermediate element (25) is movable in the body and retains at least one locking element (38) in a retracted position, under the action of a spring (28), the locking element being movable radially in the body (1) under the action of resilient means. When the rotational velocity of the hub (5) exceeds a predetermined value, a sensor element (15) moves the intermediate element (25) so as to free the locking element (38) which engages a ratchet tooth (17) of the ratchet wheel (12). <IMAGE></p> |
