Anyone with experience of using pneumatic actuators?

[jongood]

Our step motor has failed, its a 12v electric actuator pushing a bespoke hinged step over. I cant easily buy a replacement and Ive always thought that it was a bit slower than I would like and my chassis has air brakes, suspension and seating so thinking about installing a pneumatic actuator with a 3 way solenoid valve? Does anyone have any experience with using/speccing pneumatic actuators?

 

[Jev88]

Pictures of what you have?
Many steps are powered by adapted windscreen wiper motors.

 

[Arthur01]

Try having a look at RVOC, certainly the floor section in a Monaco Motorhome is air driven - we had one previously.
Drop a message to Adi4 in Weymouth as he might have something on the shelf.
Arthur.

 

[Barclaybasher]

Can't you get the step motor repaired?

 

[jongood]

Can't you get the step motor repaired?

The motor runs, but the worm has gone, sealed unit, apparently

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[jongood]

Pictures of what you have?
Many steps are powered by adapted windscreen wiper motors.

It looks a bit like this, but Im an impatient person, I would like it to be a bit faster, hence the question about air

DC 12V 3000N Linear Actuator 2~40inch Electric Linear Motor for Door opener Fast | eBay

General purpose linear actuator;. 1× Black Linear Actuator Motor. Agricultural machinery;. Reversing the polarity will make the actuator reverse. The actuator has pre-installed limit switche inside, it cannot be adjustable.

www.ebay.co.uk

 

[DBK]

If the pneuo puen air actuator could be slowed down so it doesn't take you off at the ankles I'm sure it could be made to work.

 

[jongood]

If the pneuo puen air actuator could be slowed down so it doesn't take you off at the ankles I'm sure it could be made to work.

The flow is apparently controlled using adjustable exhaust mufflers

This is something like

 

[rb62]

Wrekin pneumatics have everything you need and more! usually very helpful

Products | Wrekin Pneumatics (Telford) Ltd

Our services are geared to understanding our customers’ requirements and expectations and providing the products and services needed to meet these in the most efficient and cost-effective ways possible. Sectors that we support include dentistry, health care/hospitals, food processing...

www.wrekinpneumatics.co.uk

 

[Bern8]

Seems like a bit of a faff. First question would be, is there a permanent air supply you can tap into? Or would it only run with the engine on? If you can get air there, then you need to measure the piston length, rig up a fixing for the piston (different fixing depending what piston you go for). Somewhere to fix the solenoid valve etc. You adjust the speed via a couple of restrictors.

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[PP Bear]

TBH, it looks to be a bit of a faff to convert to air. Lots of lines, a feed, actuators etc and all for a few milliseconds on a step. Why not keep to electric as a lot less hassle, less airlines to chafe etc and the wirings already in place. Might it be slow because the motor is old, worn and at its end of serviceable life. Get it repaired or replaced would be my suggestion, but good luck

 

[Rapides]

Pneumatic Cylinder | Pneumatic Air Cylinder

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Dunno if these could help.

 

[MisterB]

Our step motor has failed, its a 12v electric actuator pushing a bespoke hinged step over. I cant easily buy a replacement and Ive always thought that it was a bit slower than I would like and my chassis has air brakes, suspension and seating so thinking about installing a pneumatic actuator with a 3 way solenoid valve? Does anyone have any experience with using/speccing pneumatic actuators?

I'm about to remove a Thule electric drop down step and fit a slide out step instead.....PM me if you're interested (I also have a brand new unused manual pull out drop down step)

 

[bigtwin]

I think what folks are missing is that Jon sees this as a bit of a project and, quite possibly, a prototype for opening the doors on his Bond Bug.

Ian

 

[MisterB]

I think what folks are missing is that Jon sees this as a bit of a project and, quite possibly, a prototype for opening the doors on his Bond Bug.

Ian

Wow, lambo doors on his MH, stunning !!

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[jongood]

Wrekin pneumatics have everything you need and more! usually very helpful

Products | Wrekin Pneumatics (Telford) Ltd

Our services are geared to understanding our customers’ requirements and expectations and providing the products and services needed to meet these in the most efficient and cost-effective ways possible. Sectors that we support include dentistry, health care/hospitals, food processing...

www.wrekinpneumatics.co.uk

Thanks Richard, just spoke to them and they are happy to advise and supply, just got to wait until I get home.

 

[jongood]

TBH, it looks to be a bit of a faff to convert to air. Lots of lines, a feed, actuators etc and all for a few milliseconds on a step. Why not keep to electric as a lot less hassle, less airlines to chafe etc and the wirings already in place. Might it be slow because the motor is old, worn and at its end of serviceable life. Get it repaired or replaced would be my suggestion, but good luck

I would go for a repair but it seems to be sealed. Ive had a quote to supply a replacement at £840 +vat so can justify a bit of faffing

 

[jongood]

Heres a couple of photos showing the hastily contrived current solution and the now disconnected actuator

 

[PP Bear]

I would go for a repair but it seems to be sealed. Ive had a quote to supply a replacement at £840 +vat so can justify a bit of faffing

 

[Landy Andy]

Just a thought, but your unit looks very much like the rams you get on some domestic automated gates. Don’t know if that will help with sourcing and electric item, or if you are set on a pneumatic swap.

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[Bern8]

Jon, first job you need to do is measure the shaft length. This will dictate where your fixing of the piston will be. You can get a piston where it is fixed with a bolt/screwed rod. The diameter of the shaft will depend on the load it is pushing (the shop will help with that) heavier the load the thicker the diameter. From there the shop will help with S/V & air pipe required.
Next how does your switching work? The S/V can work 2 different ways, spring return when you take the voltage off, or 1 coil to energise the step to go out and another coil to retract the step. The shop will need these answers.

 

[Diabalo]

I would go for a repair but it seems to be sealed. Ive had a quote to supply a replacement at £840 +vat so can justify a bit of faffing

I would also look at repairing, it's goosed so you have nothing to lose by trying.

 

[tonyidle]

There's loads on eBay. Relatively cheap too. Search linear actuators.

 

[jongood]

There's loads on eBay. Relatively cheap too. Search linear actuators.

The problem with the 12v ones I found so far is they're even slower than what I have, stroke is 300mm so need about 60mm/second

 

[Jev88]

It looks a bit like this, but Im an impatient person, I would like it to be a bit faster, hence the question about air

DC 12V 3000N Linear Actuator 2~40inch Electric Linear Motor for Door opener Fast | eBay

General purpose linear actuator;. 1× Black Linear Actuator Motor. Agricultural machinery;. Reversing the polarity will make the actuator reverse. The actuator has pre-installed limit switche inside, it cannot be adjustable.

www.ebay.co.uk

My double step opens in less than 2.5 seconds - quick enough? That's a 12V motor.

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[jongood]

Jon, first job you need to do is measure the shaft length. This will dictate where your fixing of the piston will be. You can get a piston where it is fixed with a bolt/screwed rod. The diameter of the shaft will depend on the load it is pushing (the shop will help with that) heavier the load the thicker the diameter. From there the shop will help with S/V & air pipe required.
Next how does your switching work? The S/V can work 2 different ways, spring return when you take the voltage off, or 1 coil to energise the step to go out and another coil to retract the step. The shop will need these answers.

Ive got some latitude with the inner mounting, the stroke on the current one is 300mm. I havent got to the wiring on the current electric actuator but the switches arent latching and I can stop it both wsys so guessing I have at least 2 wires but hopefully 3

 

[jongood]

My double step opens in less than 2.5 seconds - quick enough? That's a 12V motor.

That would be plenty fast enough but the motor in the link says 5mm/s so would take a full minute for 300mm stroke. This is the problem I'm finding. The strap works really well but difficult to lower from inside and looks untidy.

 

[jockaneezer]

I'd be tempted to fit another (or attempt a repair) of the electrical actuator.
Fitting an air cylinder means somehow tapping into your existing system and funny my pipework, regulating the air flow to a suitable pressure, it may even need an inline lubricator for the cylinder and possibly fitting some sort of safety in case the step opens or closes against something (pet or small child ?) I'm presuming the present set up has a current detecting feature that stops the actuator if it senses a restriction (a bit like electric car windows) ?

 

[Jabstatt]

Do you really want to ‘muck around’ with the braking system?..

MoT issue?

I love projects but need caution.

Just imho.

Tony

 

[jongood]

Do you really want to ‘muck around’ with the braking system?..

MoT issue?

I love projects but need caution.

Just imho.

Tony

I have an auxilary circuit, that the seat cushions and the airline comes off, and it goes quite close to it.