Safety Muting Problem

Hi all,
A Typical Robotic spraying booth and X muting as per drawing.
Doesn't work as the trolleys are too close and they stay muted while the conveyor is stationery and the robot is spraying.
A person can just ignore the muting lamps and walk straight in.

I can only think of a cage system one door which closes then other can open. The operator has to load the trolleys with parts then push it into place where it catches the conveyor and the robot can then index in.
Any suggestions most welcome.

So are you saying the person can fit alongside the trolley while it's blocking the muting sensor?

What make/model light curtain are you using?

Yes mate unfortunately the parts are on the trolley and some parts are bigger than others so one needs the width. Safety mat?

rigicon said:

Yes mate unfortunately the parts are on the trolley and some parts are bigger than others so one needs the width. Safety mat?

Click to expand...

Yep, if the trolleys are hanging above the floor, a safety mat would seem to be the ideal answer. Then you also don't need any special muting functions.

OkiePC Thanks for the input. The trolleys don't hang they are on wheels and a central chain underneath carries them hooking up with a pin welded to every 2m of chain.
We could have 2 safety mats, one on either side of input and the output side the same BUT one could literary walk behind the trolley not standing on the mats. This is not an easy one. At the moment we built the cell and are still programming etc but a solution will be needed.

I think our main problem is the line is stationery (muted) far too long. Muting to me is when a line is flowing that is only product can pass through and then reset, repeating.
I don't see how muting can work on a stationery line and this is confusing everything.

Are the trolleys caught on the carrier chain before passing the light curtains? Are the trolleys all the same length and move at the same speed?

Maybe you'll have to keep the light curtain and the muting sensor, plus add two mats to each end...bummer...

I wonder if one of those sick laser safety scanners could handle this application?

I've not used them before but I would definitely investigate them for a case like yours.

http://www.sick.com/group/EN/home/p...tive_devices/Pages/safety_laser_scanners.aspx

I think you could program two sets of safety zones...one with the trolley in position, and one with it gone, so that you could switch between them and always be able to pick up on a person being there.

Instead of muting when the line advances, maybe you could mute only when a TROLLEY is within the light curtain. In other words, have something on the trolleys themselves to identify them as trolleys, and not humans.

I'm not sure what you might use, but as an example... A strip of reflective tape along the entire length of the trolley. A sensor, mounted in-line with the curtain, detect this and mutes the curtains. Therefore, it's only muted when a trolley is there. A person would not be seen by the sensor, and would not mute the curtain.



-Eric

Eric Nelson said:

I'm not sure what you might use, but as an example... A strip of reflective tape along the entire length of the trolley. A sensor, mounted in-line with the curtain, detect this and mutes the curtains. Therefore, it's only muted when a trolley is there. A person would not be seen by the sensor, and would not mute the curtain.



-Eric

Click to expand...

We did something similar to this with a large hydraulic press and a safety light curtain. When being manually loaded and ran, the light curtain was active. But there was a large auto-loading system developed, so we placed a muting module in the safety relay system and one of those non-contact safety sensors (RFID, or something similar) on the loader system. The safety light curtain is bypassed when the auto loading system is in place. Once the system is removed from the press (no longer blocking the entrance) the safety light curtain must be clear before the press is allowed to move).

It works well. I can see a sensor picking up a strip along the length of the trolleys muting the light curtain the entire time the trolly is in the curtain, but not when a person is. You'd still need the safety mats along the sides of the trolleys to stop people walking by the muted light curtain when smaller products are on the trolley.

Could this be the solution to your problem?

http://www.pilz.com/au/company/pres...cles/02500/index.jsp?country=set&countryId=47