E-stops for Car Workshop Ramps

[MdubElec]

Hi guys,

A car showroom / workshop brand we do work for has asked us to modify a few things in the workshop. One of them being to implement emergency stops into the ramp controls.

Getting involved with modifying the ramp control box is something I'd rather avoid as it was obviously wired up by the car ramp specialists and if one of the guys makes an error and can't put it back together satisfactorily it can make for a bit of embarrassment.

I have read regulations 537.3.3 and here is what I believe it states:-

537.3.3.1 - this lists loads of devices that could be used.. although I'll be using the standard red emergency pushbutton.

537.3.3.2 - this states it should be capable of breaking the full load current - my idea is to have the 3 phases go via a 4pole contactor, with the coil tapped off from one of the phases, the coil would go through a normally closed emergency stop push button, ideally with two NC contacts to allow for failsafe of the other not operating.

My first wonder is, should I be tapping off from one of the phases for the emergency circuit?

My next wonder is, if the NC contacts of the pushbutton failed to operate the em stop would not work, what is the protocol for making it failsafe?

537.3.3.4 - this states it should disconnect the supply and then not turn on immediately after re-setting the e-stop - this makes the idea above defunked.

Could someone with a bit more experience in implementing this kind of safety feature kindly give a bit of advice on the standard protocols please.

Kind regards

Mdub

 

[James]

I would stay well away from changing the design of any lifting equipment, including its control system.

you do not want to end up in a coroners court trying to explain that you didn't understand exactly what the requirements were and you are unsure about how Mr jones was killed whilst working on or under the equipment.

"but your honour i did ask a question on an internet forum and got some good advice" is not likely to keep you out of jail.

honestly the workshop should be asking the manufacturer of the equipment what a suitable solution should be.

I know it might sound dramatic but that is really the case in todays litigation driven world.

 

[MJPD29]

I agree with James here. In theory it is very simple to implement the emergency stop but it leaves you open to an absolute can of worms should something go wrong. These machines are complicated and are worked on by dedicated companies for a reason (it’s probably all they do). Steer clear and avoid any stress down the line. They have likely contacted you because the lift company are looking a large sun of money to do it.

 

[mainline]

Hi guys,

A car showroom / workshop brand we do work for has asked us to modify a few things in the workshop. One of them being to implement emergency stops into the ramp controls.

Getting involved with modifying the ramp control box is something I'd rather avoid as it was obviously wired up by the car ramp specialists and if one of the guys makes an error and can't put it back together satisfactorily it can make for a bit of embarrassment.

I have read regulations 537.3.3 and here is what I believe it states:-

537.3.3.1 - this lists loads of devices that could be used.. although I'll be using the standard red emergency pushbutton.

537.3.3.2 - this states it should be capable of breaking the full load current - my idea is to have the 3 phases go via a 4pole contactor, with the coil tapped off from one of the phases, the coil would go through a normally closed emergency stop push button, ideally with two NC contacts to allow for failsafe of the other not operating.

My first wonder is, should I be tapping off from one of the phases for the emergency circuit?

My next wonder is, if the NC contacts of the pushbutton failed to operate the em stop would not work, what is the protocol for making it failsafe?

537.3.3.4 - this states it should disconnect the supply and then not turn on immediately after re-setting the e-stop - this makes the idea above defunked.

Could someone with a bit more experience in implementing this kind of safety feature kindly give a bit of advice on the standard protocols please.

Kind regards

Mdub

There shouldn't be any need to have an emergency stop on a car ramp.
In fact, it certain circumstances, it could make it less safe as there maybe a necessity to take the ramp up asap.

 

[snowhead]

The ramps should be annually, or some other regular period, inspected for Insurance purposes.
Any variation from the manufacturers design will probably lead to them being declared unsafe /scrap.
I doubt if the company that maintain them would be prepared to alter them unless it was a design approved by the manufacturer.

As Mainline has said, there shouldn't be any need to have any extra stop controls.

This sounds like a half brained scheme dreamed up by a company H&S person.

 

[MdubElec]

Thanks everyone, I'll speak to the client and come back with an update as to how it pans out.

 

[Lister1987]

The machine ought to have safety systems already fitted as required under BS EN 60204, EU Machinery Directive and Supply of Machinery (Safety) Regulations 2008. Unless you are conversant with the above I would not touch it. Needless to say 7671 doesn't apply here.

 

[R-fur]

Plus one for walking away and not getting involved in the design changes.
If however you want to know a bit more about safety circuits for your own interest look on the Piltz website, they are the foremost maker of safety relays.