The SKORPION Trapped Key System has been developed to provide extremely robust  mechanical coded key safeguarding and interlocking for hazardous machinery. 

The system works on the principle of releasing factory coded mechanical keys in a predetermined sequence to ensure machine power is isolated before any access can be gained  to hazardous or dangerous machinery. 

After the machine control has been isolated (first key turned in the system) the key from the  isolator can then be used to release other trapped keys to enable access to the guarded  areas. 

After release of the first key (power isolation) safeguarding can be achieved without the need  for electrical wiring, this makes the system ideal for use in harsh environments.  When used in conjunction with interlock sensing they can be used to achieve up to PLe/Cat4  to ISO13849-1.

A trapped-key guarding system relies upon the transfer of keys between a power isolation switch (or control  switch) and a locking mechanism fixed on a guard.  

The essential feature of the system is that a removable key is trapped either in the guard lock, or in the  power isolation switch. The lock on the guard is arranged so that the key can be released only when the  guard has been closed and locked. This allows transfer of the key from the guard to the power isolation  switch.  

Closing the switch traps the key, so that it cannot be removed while the switch is in the ON position. If there is more than one source of power, and therefore more than one circuit breaking element to be  actuated, then a key-exchange box is necessary, to which all keys have to be transferred and locked in  before the access key, which is of a different coding, can be released for transfer to the guard lock. 

Where there is more than one guard, the exchange box will accommodate an equivalent number of access  keys. 

Where a number of operations have to be carried out in a pre-determined definite sequence, then the  transferable key is locked in and exchanged for a different one at each stage.