Machine Guarding - Deadman Switch

khurley · Jan 29, 2007

The Occupation H&S Act states:

28.An operating control that acts as a guard for a machine not otherwise guarded shall,
(b) be arranged so that it cannot be operated accidentally;

In the past my machine had a deadman switch as well as a control switch so that two handed operation was required. At some point in the past the deadman switch was been bypassed. I am specifying a new switch and I am trying to determine if I can simply use a pull-to-turn, spring return to center switch or if I need the deadman switch as well.

Any input would be appreciated.

Steve Etter · Jan 29, 2007

Obviously, it depends on the machine, etc.

However, it APPEARS to me that the switch you describe could well meet the intentions of the guideline. I find it hard to imagine that such a switch could be "accidentally" operated.

With regard to the two handed operation issue, though, I do not think this switch will help in any way if both hands really need to be occupied (as with a press, for example). If this is an issue, you still need a properly designed and built two-handed system.

Steve

khurley · Jan 29, 2007

Steve,

Thanks for the reply.

My assumption was that the switch could not be operated acidentally. This is the only machine I know of in our mill that utilized a deadman switch, so I am unsure of when to use one, if at all.

Kevin

heresrob · Jan 30, 2007

khurley said:
Steve,

Thanks for the reply.

My assumption was that the switch could not be operated acidentally. This is the only machine I know of in our mill that utilized a deadman switch, so I am unsure of when to use one, if at all.

Kevin

I always say to myself when considering a dual switch to operate a machine. Picture yourself sitting in a court room explaining to a lawyer why you only wired in one switch.
If you think one switch is all that is necessary and there is no way anyone could ever get a hand or finger or any other part of the body caught in the machine. Then I suppose you've made the right decision.

heresrob · Jan 30, 2007

khurley said:
Steve,

Thanks for the reply.

My assumption was that the switch could not be operated acidentally. This is the only machine I know of in our mill that utilized a deadman switch, so I am unsure of when to use one, if at all.

Kevin

I always say to myself when considering a dual switch to operate a machine. Picture yourself sitting in a court room explaining to a lawyer why you only wired in one switch.
If you think one switch is all that is necessary and there is no way anyone could ever get a hand or finger or any other part of the body caught in the machine. Then I suppose you've made the right decision.

bob

bluebyu · Jan 30, 2007

Part of what Steve is saying, "need a properly designed and built two-handed system." is really important. What happens if someone wedges a stick against the switch? A proper anti-tie down, anti repeat circuit for dual palms may prevent accidents. What kind of machine is it? Is it required to keep the operators hands out of danger while the machine is running?

Steve Etter · Jan 30, 2007

What happens if someone wedges a stick against the switch? A proper anti-tie down, anti repeat circuit for dual palms may prevent accidents.

Exactly.

What kind of machine is it? Is it required to keep the operators hands out of danger while the machine is running?

That is my question as well.

Many machines can be operated safely with a one-handed start system while others cannot. Without any info on the machine, we are all just guessing.

Steve

TConnolly · Jan 30, 2007

Regardless of whether the machine is operated with one hand or two, the deadman switch should be equipped with some kind of tie down detection. Anti-tie down controls is not necessarily limited to two hand controls.

darrenj · Jan 30, 2007

khurley said:
In the past my machine had a deadman switch as well as a control switch so that two handed operation was required. At some point in the past the deadman switch was been bypassed.

Any input would be appreciated.

This is the Key!! Your machine had a dead man switch. It had one for a reason..do yourself a favour and put it back in!! also when you put it back it make it difficult to bypass it again!!

rdrast · Jan 31, 2007

The best Two Hand controls I've seen yet are still these neat Safeballs.

Machine Guarding - Deadman Switch

khurley

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Steve Etter

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khurley

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heresrob

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heresrob

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bluebyu

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Steve Etter

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TConnolly

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darrenj

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rdrast

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