Pull Cord vs Emergency Stops

[Big Country 3]

If you mount the Cord at arms length from the operator I think it would be more accesible and easier to activate than a conventional estop. Can I get some feed back on this I have been debating about this I finally decided to go with the pull cord.

[TimWilborne 108]

We use cables on our long conveyors. Some are over 100' long. The operators like the cables much better. The only thing i would suggest is pay the extra money for the tensioner and switches with tension gauges in them. You can even get the switches with estop built in them so you would have both. If you go over around 20' or have a lot of bends, put a switch on both ends. It seems to help with tensioning the cable properly and with nuisance tripping.

[gravitar 3]

At the last machine guarding class I went to, I believe they said that by OSHA requirements you MUST use a pull-cord E-stop on ANY conveyor 10' or longer.

[OkiePC 14]

Pull cords are definitely safer for the operators than a pushbutton. The ones we use now require tensioning and include an indicator lamp and pushbutton. If the cord breaks or gets loose, the circuit will open. I don't know the exact OSHA requirements, but our plant has standards that require the cable to be red in color and a minimum amount of force required to open the circuit. Ours are tested regularly with a fish scale.

[Wordman 0]

I wonder what standard they are referencing, I've never heard that one before. I can't find my book, but ANSI B20.1-1957 is what the OSHA standards mandate. However, every code I've read has said basically the same thing: E-Stops must be accessible to all employees in the area. Climbing over any obstacle, conveyors, ect., do not meet the basic requirement of unobstructed view and operation.

[gravitar 3]

I emailed the guy that was doing the class to find out.. He's out till next week but as soon as I get an answer I'll post it here!

[GerryM 2]

If there is a single point of entry or operation than a button is fine, otherwise I like the pull cords. No matter what happens in an emergency you can usually reach the pull cord.

[Big Country 3]

The project that I am working on is a two window robotic cell. Probably could have gotten by with two e-stops but I'd rather be safe than sorry. The pull cord switch that I'm using is a Schermsal, does anyone have any feedback on this type of pull switch? Good or Bad!

[OkiePC 14]

Most of our newer machines (<3 years old) use Schmersal cable switches. I haven't had any problems so far.

[Big Country 3]

Well I got the pull cord installed and everyone loves it. Thanks for all the input.

[gravitar 3]

In the "better late than never" category.. I finally got my CD for the training in August! It says "Every belt conveyor over 10 feet shall have an Emergency Stop cable extending the length of the conveyor" and it cites OSHA section 1910.261 and ANSI B20.1 as the source for that.

[Wordman 0]

Ahh well that makes sense for belt conveyors I suppose. I looked up the OSHA 1910.216 for fun: The debate continues