EDITOR’S CHOICE
FOREFRONT OF INNOVATION
IDEM SAFETY SWITCHES
SKORPION TRAPPED KEY
INTERLOCKING WITH KEY EXCHANGE
Established in the United Kingdom in 2003
IDEM Safety Switches are the UK’s largest
machine safety switch manufacturer.
Continually at the forefront of innovation
within this market and in providing the
“Next Generation” of machine safety IDEM
developed and introduced the SKORPION
Trapped Key Interlocking with Key Exchange
system in 2016.
Designed and manufactured in the United
Kingdom, SKORPION has been developed
to provide extremely robust mechanical
coded key safeguarding and interlocking
for hazardous machinery. All components
of the system are available in Stainless
Steel 316 or mirror polished die cast metal
options.
The system works on the principle of
releasing coded mechanical keys in a pre-
determined 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.
OPERATING PRINCIPLE
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 interlock on the guard is arranged so
that the key is trapped and 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 isolator switch
is in the ON position.
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PECM Issue 37
If there is more than one interlock then a key-
exchange block 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 other
guard interlocks.
Where there is more than one access guard,
the key exchange block will accommodate an
equivalent number of access keys.
Where a number of operations have to be
carried out in a pre-determined sequence,
then the transferable key is locked in and
exchanged for a different one at each stage.
Please see the example for a visual
explanation.