Non-(easily)-resettable emergency stop switch

[skotl]

The big red mushroom emergency stop kick switch on my mill has never worked, so I figured I should (three years later!) figure out what was wrong with it.

Turns out it seems that the switch has been deployed / kicked and then latches in the "interrupt" position. It's resettable, but only by unscrewing the body and manually pushing the switch back out.

It definitely does not have any turn-to-reengage type functionality like most emergency stop buttons I've seen.

First time I've seen a switch like this - designed, it would seem, to be resettable but only by a maintenance engineer (aka bloke with a screwdriver). Are these common - maybe in schools?

 

[Hood]

I have seen the 1/4 turn and also the ones where you have to physically pull them back out. Can't recall ever seeing one that needs dismantled to reset.

 

[skotl]

I have seen the 1/4 turn and also the ones where you have to physically pull them back out. Can't recall ever seeing one that needs dismantled to reset.

Yeah - the 'shroom isn't physically connected to the internal plunger, so pulling/fiddling with the mushroom doesn't do anything to the plunger.
Weird...

 

[Hood]

Yeah - the 'shroom isn't physically connected to the internal plunger, so pulling/fiddling with the mushroom doesn't do anything to the plunger.
Weird...

Probably designed for the Edinburgh IT crowd

 

[m_c]

I'm guessing something is broken/missing.

 

[mtt.tr]

Yes sounds broken

 

[brightspark]

put a new one on or bypass it there only a tenner

 

[Robotstar5]

All ours can only be released with a key, stops the track workers operating them then pulling them out and denying all knowledge while they have a few minutes break.

We do hear some interesting stories of how they "accidentally" operated a stop mounted 2 metres high

 

[mtt.tr]

We do hear some interesting stories of how they "accidentally" operated a stop mounted 2 metres high

Give us a good one

 

[Robotstar5]

Give us a good one

Using a pneumatic assistor (device for loading heavy items such as seats, batteries, etc.) and it swung round and hit the E-stop, the only problem is, to reach an E-stop the assistor would have to go past it's over travel limits which would stop the track anyway, but would show a different fault on the alarms screen.

 

[skotl]

I take the points about it being broken, but I honestly don't think so as I've had it completely apart and it seems to be working as it (is poorly) designed.

It's no biggie, and I know they're cheap to replace, but it seems to function. I'll take some pics if I get a chance to see whether i'm missing anything blindingly obvious.

 

[scottmk1]

I never touched that thing so can't say if it ever worked at all. It does sound like a strange setup though.

 

[skotl]

I never touched that thing so can't say if it ever worked at all. It does sound like a strange setup though.

Funnily enough, when I opened it up the cable was connected to the NO contacts but, because the switch was engaged that allowed the motor to start and stay running (but obviously wouldn't kill it with a kick!).
So I guess the previous owner hit the panic button then swapped the wires over to NO to get it to start!

 

[Ali]

Can you post a pic? Does it happen to look like this

 

[Pete.]

Every E-stop I ever saw was either pull to reset or twist to reset. Some had a key but you still have to twist.

 

[Hood]

Can you post a pic? Does it happen to look like this

View attachment 211539

I love how they must have got a professional photographer to take that picture, white reflective umbrella and everything and yet they still manage to have it in the shot

 

[skotl]

Can you post a pic? Does it happen to look like this

View attachment 211539

It looks exactly like that, even down to the off-centre cut out on that face! Two other faces have centre cut-outs and the fourth face has none.

Now the $1m question - is how I described it how it is supposed to work?

 

[Hood]

It looks exactly like that, even down to the off-centre cut out on that face! Two other faces have centre cut-outs and the fourth face has none.

Now the $1m question - is how I described it how it is supposed to work?

Does yours have the white brolly?

 

[skotl]

Does yours have the white brolly?

It did, but it blew away in the storm

 

[Ali]

It looks exactly like that, even down to the off-centre cut out on that face! Two other faces have centre cut-outs and the fourth face has none.

Now the $1m question - is how I described it how it is supposed to work?

Yes, Klockner Moeller. Good stuff, not £10 more like £50. You do have to pull them very hard to get them to release. I’ve spoken to many a user with a ‘broken’ machine, and even embarrassingly sent a spark out to one only for them needing to be pulled out. There are two types, the yellow one is latching (yours) the grey is non-latching (no good through an NVR). They are quite tough, I’ve only seen one or two broken, probably by bored kids or users trying to lever it out with a crowbar before realising some other part of the e-stop circuit is the problem. If it really is broken PM me your address and I’ll dig out a used one you can have. There are also NO (normally open) and NC (normally closed) contact blocks - they’re supplied with both so it could be wired up wrong.