| 摘要 |
<p>The combined emergency drive and safety catch unit is for use on electrically-operated roller door or roller shutter installations. It operates simultaneously as a check against unrolling action on the part of the roller casing, and can be used as a high-speed emergency drive for roller doors or shutters, for rapid and effortless opening or closing of these, in the event of a power failure. It involves use of a spring system, in the form of helical torsion springs, or leaf springs, stretched in a spring cage, and linked with an electric drive, with checks against self-locking by means of slip-coupling, claw coupling, or electric brake.</p> |
