Safety Switch suggestions


Thread Starter

Pete Squires

We currently use Sipha switches from Guardmaster. Our guards generally aren't extremely solid. From time to time we have problems with these switches not having enough distance until they open. Does anyone have a switch that they really like. Guarding system must be dual channel.
Guardmaster (now an Allen Bradley product) has an excellent line of switches. I can also reccommend the Square D/Telemecanique, Euchner, and Schmersal Safety switches.

The key is selecting the right type of switch for your application. Maybe the Guardmaster Rotacam or Trojan 5 is better suited to your application, or maybe you just need to move the Sipha closer to the pivot point.

Pete Squires

We do use Trojan 5 and have had excellent results with it. I am looking at something with a longer range in a non-contact device.

Roberta Nelson Shea

There are many safety switch manufacturers offering a wide variety of products. You have already gotten replies suggesting a number of companies. I would add another company to the list to investigate: Honeywell. They offer a wide variety of safeguarding products, including electromechanical and non-contact. Look at "": .

Doug Ruggles

If you would like a hassle free switch use Banner Engineering's new hinge switch. This a sweet little device that you select the trip point. Remember this though, if you select the wrong switch point or if your switch point were to change it means replacing the switch. The cool thing is you need a hinge anyway. Why not use one with a switch?

Hope this helps.

Michael Griffin

We had a look at a similar product from Schmersal recently. There was one application problem we noted with this type of product. It is sometimes convenient or even necessary to completely remove the guard doors from a machine when doing some major work on it. We often use hinges which allow the door to be lifted off the hinge pin for easy removal. Since the switch actuator is attached to the door, you know that the door must be returned to its proper place before the guard interlock can be energised (unless of course someone deliberatly inserts a "cheater" or jumper). This is true even if the hinges are unscrewed from the door for removal.

However when the switch is part of the hinge, you don't know that the door is closed, you only know that the hinge is in the closed position. If the door was removed from the hinges (for the above noted reasons), then there is the possiblity of re-energising the machine without all the guards in place.

I suspect that a design using these "hinge switches" may need to incorporate some means of preventing this situation from arising. It may also require much more careful mechanical design to ensure that there is never a reason for someone to want to temporarily remove the doors. It is not sufficient to say that "you ought not to do that" if you are providing them strong reasons to want to (or need to).

Michael Griffin
London, Ont. Canada
The Euchner's non-contact safety switch can get up to 18mm range. As well they have a Transponder style system which can not be fooled like the other magnetic styles. i.e. no maintenace person with a spare actuator "fooling" the system.