Ensuring security of machines and users is essential for industrials. Specific pneumatics for example are there to implement protection functions.
Definition of a pneumatic 2-hand control
A pneumatic 2-hand control device is used with dangerous machinery and requires the simultaneous use of both hands to trigger and maintain machine operation.
How does a pneumatic 2-hand control work?
Such a device must be located outside the dangerous zone, so that the operator cannot enter this zone before the machine has come to a complete standstill.
A pneumatic 2-hand control device is composed of 2 parts :
– 2 manual pushbuttons which require the simultaneous use of both hands.
– A pneumatic relay.
It is mainly used on press control applications, cylinder….. requiring the use of both hands in order to prevent the operator from being trapped or even crushed when using the press.
Safety levels and norms
The safety function of this safety device has to comply with functional safety levels and to satisfy norms following the provisions of the Machinery Directive 2006/42/EC.
- EN 574:1996+A1:2008
- EN ISO 13849-1:2015
- EN ISO 13849-2:2012
- EN ISO 13855:2010
Extra tip : keep safe with motor STOs
On some motors like the Crouzet SQ75, two Safe Torque Off inputs provide an emergency stop feature that shuts down the motor immediately while maintaining power to the microprocessor.
This can be another solution to protect operators working on a machine integrated on a safety chain and requiring a special operation. In that kind of applications, the operator simply has to push the red button on the machine and the motor will stop immediately to protect him.