I can find loads in Farnell, RS, etc, but I can't determine whether they fit my requirements. What I need is a small 6/12V device with a pull stroke of about 5mm. But the slug should be spring loaded and return to the 'out' position when the coil is not energised. The slug should also be retained. The physical size should be less than 5cm. Does anyone know if this type of solenoid has a special name, or if any of those on RS, Farnell, fit the bill. Ta.
Sounds like a door interlock solenoid bolt. I think they're usually spring loaded to return to a known state on a power-loss, and double- ended so you can have a normally locked (bolt extended) or normally unlocked action when unpowered.
In message , Grumps writes
You might try automotive applications. These crop up as hydraulic pilot valves on agricultural tractors. The last one I fiddled with was about
30mm x 40mm and 12V and used to control the *dump* valve on a torque converter.regards
I would have thought that having a door bolt remain in the locked position when unpowered would contravene all sorts of H&S regulations, as well as common sense.
By "door" I don't mean domestic house doors.
Think of things like on equipment/machinery enclosures, with access doors.
There's many situations where it is safer for such doors to remain locked on a power failure - such as enclosures that are too small for a person to get inside - and you don't want someone sticking their hand inside whilst the machinery spins down or electrical systems discharge.
My mistake, I was thinking of doors one might want to escape through if the building's on fire.
Yes it most likely would. Thanks.
[And thanks to all for the other replies too.]
Would a doorbell/chime solenoid do?
Owain
Would a model train turnout (Points) motor be any use?
They are small and powerful and in the voltage range you specified.
Just a thought, but never handled one myself.
I thought Dom was referring to entry-phone type door systems. Failing locked in that situation is the right choice, as you don't want people getting in. Getting out, you use the manual latch on the inside of the door.
Pete
Does it have to be a solenoid? BMW etc boot lock central locking motors do exactly that. They operate the lock at the touch of a button, but return under spring action to the rest position so closing it latches it. The motor drives a rack so the action is the same as a solenoid.
Maplin do cheap motor driven 'solenoids' again for central locking. But you'd need to arrange for the spring return.
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