Its probably using a worm drive which of course cannot be operated
backwards, so to speak.
Brian

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The Sofa of Brian Gaff...

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"Chris Hogg" wrote in message
...
On Thu, 6 Jun 2019 07:51:40 +0100, "Jim GM4DHJ ..."
wrote:

this new motorised roller shutter doesn't seem to have a lock...is that OK
?

Are you talking garage door? If so, nor does mine. It relies on it not
being possible to raise it other than by coiling it back up onto its
axle, either electrically using the remote controller or with the hand
crank inside the garage if the electrics should fail. I asked about
security before I had it installed, and the guy said it was very
secure (BHWSTWH).

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Chris