On 26 Feb 2009, at 14:16, Bru wrote:
> They weren't entirely mythical but they probably couldn't do all
> that was
> claimed for them - however, they were hardly *covert* surveillance
> cover (as
> somebody suggested)! More a blatant gimmick really.
I think you may have missed the point: they could be used for other
kinds of surveillance (Fuzz, MI5 and the like) without alerting the
target, as they were at one time a semi common sight around urba areas.
>
> <snip>
> The trolley lock device, or at least the type of which I know, is
> indeed an
> inductive loop which releases a brake on one or more of the trolley
> wheels.
> The brake can only be released with the right key. AFAIK, there are no
> 'gizmos' involved in releasing the brake, it's an electro-magnetic
> release
> of a sprung loaded brake which is then reset mechanically.
That's what I expected to see when we had one unlocked at Rugby, but
no, it didn't involve any kind of mechanical, special spanner type
jobby, it was a flat plastic box he held next to the wheel, and
pushed a button whilst shoving the brake block back into the wheel
housing. Presumably another induction system to hold a detent out of
the way whilst the brake was reset.
All the best
Bruce
There are no strangers on the cut, only boaters we've yet to meet.
[Non-text portions of this message have been removed]
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