Dead Man's Switch?

Steve,

I've gone a lot better. I have a hinged Dexion rail across my machine bench that will activate a 'twist to release' stop switch that breaks the power circuit to any of the three machines via the no-volt release DOL starters. I only have to lean on it so if I am fully engaged in holding onto something at the drill for example I can kill the power this way.

The system is like a Panic door in public places for fire exiting in a hurry. To continue in operation I lift the rail, reset the switch and then restart whichever machine I was using.

It has been tested for real on a few occasions and much more often by visitors leaning on it to get a view of the action. Much much better than a foot switch in my view.

Regards Brian

Tromp bar along the front of the lathe linked to a switch in a suitably protected location is a sensible idea and works well. One day I might fit one to mine!

The bigger and more industrial variety of pillar drills often have a hefty cast-iron box with a big mushroom switch on top fitted to the base front or front of side. The one I have about the place would fit in a 3" or so cube box and is much too heavy to drop on your toes. Theoretically ago idea but when I've used drills so fitted I'm pretty certain I'd not remember where to stamp in an emergency. My Pollard 15AY is not so fitted despite being an industrial class three phase machine with gear drive probably quite capable of swinging me around as well as the work should a big drill grab.

A better approach for a drill would be a tromp bar or pedal that had to be kept depressed by your foot for the drill to run. Lift your foot and the drill stops.

Clive.

Schools have their pillar drills fitted with foot operated emergency stop switches. They are there because if a drill binds in a hole and you are holding onto a vice with one hand, and the other is holding the handle for the quill movement, which do you let go of to switch off the drill with its normal stop switch??? Foot operated switches have been adopted for other machines as people see them on drills.

If you are looking for accessible machine safety a wire rope switch is probably the best idea. It can be run around the machine, or even a couple of machines. You can purchase a kit containing the switch, tensioner, wire rope etc.

Martin

Fit an estop between your butt cheeks, any crises is sure to result in a clench.

Mike

Yes - I rigged a remote foot switch to my no-volt switch when I was teaching my young nephew to use my lathe. That way, I could stand close behind him with my foot hovering over the switch, just in case he got into trouble. Fortunately I never had to use it.

Bloody schools should be teaching their students to bolt the vice down on the drill press, even if it is just one bolt loosely tightened through the vice and table so vice is free to slide around to position the job but not to rotate if a drill grabs -- thus allowing either hand to be safely removed to hit the stop switch if needed.

In answer to your question: let go of the handle, hang on to the vice. No harm will come from the quill popping upwards if the drill frees itself up.

Edited By Hopper on 10/12/2017 20:12:14

I used a Colchester with a foot stop bar with brake, a very satisfying setup. If you get into the habit of using a foot stop then if an emergency arises it will be automatic to stomp on the bar. Fitting an estop has to be in an intuitive position, an estop or normal stop is the same thing on a basic machine like a lathe or a drill. It gets more complex on equipment like robot lines and cells where a controlled stop can be quicker than an estop that just kills power to the machine. A foot stop on a drilling machine is probably worth using as your regular method so your foot is trained to hit the stop then anemergency stop situation is automatic. A proper starter with a correctly set overload is also useful so that in the event of a jam up if you just hold on it will trip and the crises is over. A bit of thought before starting the machine will probably avoid most crises but the unexpected can always happen.

Mike

Edited By Mike Poole on 10/12/2017 22:51:27

Hi, I would says a tromp/panic bar that you would have to stamp on would be the best approach. It can be surprising how long a delay there can be before you realize that you have to lift ones foot or let go of something, before you have to execute an emergency stop, I think this is because psychologically it is more logical to hit something, rather than letting go.

Regards Nick.

instead of a tromp/panic bar to stop the drill, install a foot mounted start switch. (mentioned previously)

Put it under a protective cover so that it is not accidentally stepped on and starts the drill. In an emergency, take your foot off the switch.

Paul

I have a foot (kick) operated emergency stop on my mill which I invariably use to turn it off. The action is so embedded that I also regularly kick the bench at work and then wonder why the Seig 3 is still rotating.

regards Martin

Yes.I have an industrial quality foot switch controlling my drilling machine, the switch is wired in series with the stop push. My foot has to be pushing down on the foot switch whilst I press the GREEN button. otherwise nothing will happen Take my foot off the foot switch and the motor stops. As the contactor coil current is very small, thin supple armoured cable can be used (Sy), don't want a piece of sheet steel falling and cutting into the cable, I have seen this happen. I have a drill vice and clamps and do use them, especially when drilling sheet steel John

One thing to watch out for is the amount of space under the cover. I have known an operator to get his boot stuck so that he couldn't release the switch. If the foot switch is before an NVR there is less need to cover it as the machine cannot be accidentally started by treading on the switch.

Brian