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
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.

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

--
Tim Lamb

On 13 Nov, 08:45, " wrote:
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.

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.

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.

On 13 Nov, 12:10, " wrote:
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.

Owain wrote:
On 13 Nov, 08:13, "Grumps" wrote:
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.

Would a doorbell/chime solenoid do?

Yes it most likely would. Thanks.

[And thanks to all for the other replies too.]

On Fri, 13 Nov 2009 08:13:40 -0000, "Grumps"
wrote:

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.

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.

pcb1962 wrote:
On 13 Nov, 08:45, " wrote:

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.

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.

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

In article ,
Grumps wrote:
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.

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.

--
*He who laughs last, thinks slowest.

Dave Plowman London SW
To e-mail, change noise into sound.