Antiopen lock for suicide door conversion ?

[CompoSimmonite]

I'm converting my Marlin Roadster kit car to suicide doors for better access (I have mobility problems).
The actual locks are going to be Spridget items as I've got a set left over from breaking a Midget years ago - knew they'd come in handy one day !
To be legal suicide doors require a method of ensuring they can't come open when the vehicle is in motion. You can get kits but they are little more than a manual sliding bolts whereas I want something automatic. That means some sort of additional solenoid operated lock. Problem, however, is it need to only lock when solenoid energised and automatically unlock when stationary / power fails / after accident and such. I thought taxi rear door units would work so bought a pair off eBay but they simply make the main door lock so it can't be opened rather than a separate fail safe lock as I require.
Yesterday I spent ages thinking about this problem as until it's solved I can't start work on exactly how the new doors will be made (Marlin has a blanking panel below the door hidden by running board that I'm removing so doors will be deeper as well as suicide).
Forget the control aspect at present - taxi will probably still provide a suitable speed sensing ECU.
Today I'm thinking a way around the problem could be adapting a pair of bearclaw locks so the latch spring keeps it open until a solenoid pushes it closed.

Any views, input, opinions etc appreciated.

Thanks.

Paul h

 

[500e]

Solenoid held by latching relay, crash safety use a inertia fuel shut off valve to break latching circuit. the solenoid\relay can have holding coils to reduce current drain.

 

[CompoSimmonite]

Solenoid held by latching relay, crash safety use a inertia fuel shut off valve to break latching circuit. the solenoid\relay can have holding coils to reduce current drain.

One of the types of solenoid I've considered is a diesel stop item that pulls a cable. I wondered why three wires but now I know - earth power and "holding"

Paul H

 

[mike os]

should not be too hard to source as many modern cars have auto locking once the speed is over a few mph (5iirc)... obviously will need some work but the kit must be out there

 

[CompoSimmonite]

should not be too hard to source as many modern cars have auto locking once the speed is over a few mph (5iirc)... obviously will need some work but the kit must be out there

The control off a modern car could be used but the lock is a different matter. Normal modern car doors have central locking so easy to link with that but I'm using Midget locks as they are small / direct operation ie no linkages between the lock and interior handle. The locking function is incorporated into the handle so not possible to use a central locking solenoid hence the need for a second lock that can be adapted. The doors are only 1" - 1.5" thick so whilst I can have a bulge for the Midget lockset something off another car would be difficult to incorporate.
Another thought is boot lock as they might be more adaptable than a bear claw.

Paul h

 

[shed or dead]

How about a 'normally on' electromagnet from a buildings door buzz in? Even smaller units should provide more than sufficient grab to satisfy requirements.

As auto electrics are my weak point I find it daunting to adapt looms from other vehicles (and often expensive) so I would look into using an Arduino or Raspberry PI for control personally. It wouldn't be difficult to program one to only allow the magnet release when no electronic speedo input was readable (if you have an electronic speedo feed). Even easier would be to join a relevant forum and find someone to put together the few lines of coding required. Perhaps we have someone on here who knows about these things, unfortunately it's not me, I'm just aware of the possibilities.

Should be easy enough to modify the midget locks so that an electromagnet could stop them from operating, saving having a cumbersome 2 point system.

P.S I'm a Marlin owner also, any pics of the car as is please?

 

[500e]

With latching relay & inertia sw there is no need for complications like pye.
KISS

 

[dan.taylor.1]

You just need a pin that's held in by the relay with a spring pulling it so if the power dies the spring pulls the pin and solenoid back hence u locking the door, if you're really clever you could wire it to a speed sensor so it locks automatically at a set speed and unlocks below it.

Dan

 

[Robotstar5]

A linear solenoid with spring return, the shaft would engage in a hole to keep the door shut when energised, when power is removed or fails the spring retracts the shaft - link

 

[CompoSimmonite]

I used to have a FX4 Black Cab as an engine donor for my Land Rover. The prop flange on the back of the gearbox has a castle type "chopper" and sensor that sends signal to a common, therefore cheap and reliable, control box which both triggers the rear door locks and also works the taxi meter that calculated mileage / charge. This is what they look like -

Unfortunately I didn't keep it off mine when I had it crushed (really - saw it made into a cube )
Also there aren't any workshop manuals for taxi's so I can't find any reference to how they are wired or how the actual door locks works. The mechanisms I bought are from the later LT1, TX1 etc modern version and not adaptable that look like this -

Inside is a solenoid and microswitch. All the solenoid does is move a nylon block forward to it triggers the microswitch and I assume pushes a pin on the door lock to stop it being unlocked.

Paul H