Looking for specific type of keyed switch

Hello,

I'm looking for a simple 22 or 30mm keyed selector switch (varying configurations of NO/NC, and Maintained/Spring return positions) that also has a "Key Inserted" status.

I've looking around a few placed and have come up with some very complicated and fancy safety devices that do something similar (though, not exactly), but I was hoping for something like the Allen Bradley 800T range selector switches, but with a contact that would let me know when the key was simply inserted into the switch. Just for status to a PLC.

Just curious if anyone out there has stumbled upon a product like that.

Thanks in advance.

Tharon said:

Hello,

I'm looking for a simple 22 or 30mm keyed selector switch (varying configurations of NO/NC, and Maintained/Spring return positions) that also has a "Key Inserted" status.

I've looking around a few placed and have come up with some very complicated and fancy safety devices that do something similar (though, not exactly), but I was hoping for something like the Allen Bradley 800T range selector switches, but with a contact that would let me know when the key was simply inserted into the switch. Just for status to a PLC.

Just curious if anyone out there has stumbled upon a product like that.

Thanks in advance.

Click to expand...

I've never seen that anywhere. It would be difficult to do, because the action of just inserting the key would have to force a set of contacts open (or closed), which might be problematic.

What I do know exists however is a keyed selector that will EJECT the key when in one position. So if you use a 3 position switch for a 2 position function, and eject the key in the center position, the key can only be left in the switch if it is in the right or left position, which DOES have a contact associated with it that can tell you that the key MUST be inserted. Kind of a round-about way to get there, but I don't know what you actually want to do this for.

I've only seen this offered in 22mm though, if that makes a difference. A-B has them available in the 800F line, I've seen them in Siemens 22mm as well.

I am looking to make sure that an operator is taking a key out of a switch after actuating it. Not leaving it in the switch. The key stops the switch from being actuated without it, but the operator needs to take the key with them once they do actuate it.

The eject option on the 800F series may work. Looks like it has limited operating configurations and key styles though. But now that I know the eject option exists I may find something similar elsewhere.

Thanks.

How about putting 2 different keys on a non-openable key ring (regular split key ring with a little TIG welding at each end). Key 1 is always kept in a 2 position switch that the key can not be removed if on, it has to be turned off, removed then put in switch 2 to activate it. If switch 1 is OFF then the key is probably in switch 2 whether it's ON or OFF. Also, to remove the key from switch 2 it will have to be off also.

You may also be able to do this with the same key operating 2 separate switches if both have to be OFF to remove the key. Make sure switch 1 is ON and switch 2 is OFF to run.

Not sure if Allen Bradleys Trapped Key range offer this but I have used it for machine access before and its a fantastic product but not cheap.
Maybe have a look through the range and see if they do or if you can change the process to suit them.
http://ab.rockwellautomation.com/Se...rlock-Switches/Trapped-Key-Interlock-Switches

A possibility: http://www.fortressinterlocks.com/

As Gary mentioned a trapped key switch offers this functionality - although the key is a little less traditional. I've used AB 440T-MSRUE11FA with key 440T-AKEYE10FA. It has a key inserted output as will as a lock key input which will not allow the key to be removed.

The 440T stuff looks like it would work, but from the catalog:

"Rotating the trapped key causes the isolating power switch to change state"

I'm not just looking for whether or not the key is rotated, but whether or not the key is in the switch (in either position).

Here's the scoop:
This is for a caged, hazardous area.
Currently, we have a keyed locking system like above. You have to disable the caged area, unlock the door, and enter.

But, the Insurance Company and OSHA are no longer happy with just that. They fear that someone coming by can use the key to activate the caged area again while someone is inside working.

I'm trying to make it so the user is forced to take the key with them before the caged area will unlock, they cannot leave it behind. They still have to go through all the sequences, but after they do all the steps, they have to take the key out and pocket it. Then they can enter the hazardous location (which is now safe, because of the lockouts previously). And they have the only key on their person, and that caged area can no longer be activated. Everything I see in the catalogs all are triggered by the key being turned or not turned. Unless I'm missing something. I even thought maybe the exchange units would work, but didn't see anything for "key removed" status.

It seems overkill to me. But that's what they are demanding. Basically a entire lockout system that is enforced by the machinery being locked out.

use the same key for a switch inside the cage..

jimtech67 said:

use the same key for a switch inside the cage..

Click to expand...

That's the plan. Actually what we already do. There is a keyed switch inside the cage that must be activated (spring return) and a timed safety relay that you must leave the cage and reset everything within or else you have to activate the switch inside the cage again. (This forces anyone wanting to start the motion to actually enter the caged area and hopefully see anything that is not supposed to be there)

But they can get inside the cage without removing the key. The powers that be don't want them inside that cage unless they are in control of that key. So I can't unlock the door until they remove the key from the switches outside the cell. Not allowing them to leave the key behind if they want to enter the cage.

It's a mess, really. It's hard to explain, and everything I see doesn't really do it that way.

I'm tempted to get a tongue switch and weld a key to it. And use this "Tongue-Key" to activate the reset inside the cage, but not unlock the cage until they remove this "Tongue-Key" from the switch outside the cell after doing the sequence as is.

So what I'm trying to do is:

Operator requests to enter cage
Cage area motion stops
Operator removes Key
Cage unlocks
Operator opens cage and power is isolated from dangerous motions
Operator does work
Operator activates timed safety switch inside cage (with Key)
Operator leaves the caged area
Operator closes door (Within set time)
Operator places Key back into outside switch
Operator puts cell back into run mode
Cage locks
Power is applied to motions again

How about using 2 keyed safety interlock switches:

http://www.automationdirect.com/adc...noid_Locking_Tongue_Interlock_Safety_Switches

Operator must remove "key" from outside switch and put in inner switch, with some type of noticeable key fob in it.

That's my current plan, using a tongue switch in combination with the keyed switch. It seemed kind of makeshift to me, so I was trying to explore other options. I was also not familiar with how many different types of tongue keys existed. Since this would have to be unique among a number of similar setups. Keys were relatively easy to code differently.

I've never seen a caged requirement be so strict though. They are very insistent about it.

It's not a 30mm mount but...

http://www.wattstopper.com/products...hs-series-card-key-switches.aspx#.Vkurl8oo61s

Doug-P said:

http://www.wattstopper.com/products...hs-series-card-key-switches.aspx#.Vkurl8oo61s

Click to expand...

That's an interesting solution. I'll put that on the list. I'm sure environment will be an issue for that specific item, but it does open give me an idea about other RF ID options. Tagging the Key itself with an RF ID device. Then that is used to unlock the gate, but not by sticking it in something (where it can be left behind), but just by holding it up to something.

How about a slightly different approach.

Get a fortress key. The operator has to remove this key from the operator station, which isolates the dangerous motion. This key then unlocks the safety cage (that part is exactly what fortress keys are designed for). Then the sequence goes:

Operator requests to enter cage
Cage area motion stops
Operator removes fortress key, which isolates motion
Operator unlocks cage (power is already isolated from dangerous motions)
Operator does work
Operator presses button to signify "I'm about to leave"
Operator leaves the caged area
Operator closes and locks door (Within set time, confirmed by feedback on door fortress lock)
Operator places Key back into outside switch and turns it back on, restoring power to motion

This means that the motion is isolated before you can even unlock the cage, which is probably a better approach anyway.