Quote:
Originally Posted by HarryM1BYT
Point is - if that bit of 1/16" diameter shaft snaps, there is absolutely nothing to stop a roller door coming crashing down at high speed and they are heavy.
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I dont know anything about roller doors, although my old employer had them on the warehouses of his premises. I always assumed them to be a basic motor with a gear, and a gear on an axle carrying the shutter. Around the axle on the shutter, there was a chain, which allowed you to 'shuffle' it onto a wheel welded to the gear, so if the motor or power failed, you could manually raise and lower. Therefore there must have been some form of clutch arrangement within. I never had to use it.
Another employer, again with a roller shutter, manual though this time. If I recall, you had to pull down on something, and then pull the chain to raise and lower. This pull, acted on a pivoted lever which I assumed locked into a gear tooth, so once released it would lock the door.
I imagine these types would be a lot noisier than a tube motor (which until I read your post, I had never heard of!) It got me thinking of them - safety etc. With no engineering experience nor motor experience (except from model railway, scalextric and a rear sun blind) - could it be converted to a worm gear arrangement. Should it snap again, the worm gear would lock it in place? (and perhaps be a compromise on noise)