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August 18, 2011

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Machine interlock – Castell trapped key interlocking system

Food-to-go manufacturer Uniq Prepared Foods is said to have virtually eliminated downtime from the bacon-slicing process at its facility in Northampton, thanks to a trapped key interlocking system from Castell.

As part of its continuous improvement programme, Uniq replaced the electrical safety switches on its bacon slicer with a panel-mounted KSSE20 multi-key solenoid-controlled switch and four AI access interlocks. The safety switches had been prone to misalignment, with each incident requiring the intervention of an engineer, and typical downtime of half an hour. Castell says its heavy-duty interlocks not only resolved this issue but their stainless steel construction makes them much more suited to the daily hosing down given to the machine.

Engineering manager at Uniq, Mark Caulfield, said: “Castell’s interlocks have completely solved the problem. The trapped key system has worked really well and been welcomed by staff.”

When access to the bacon slicer is required, the machine must first finish its cycle so that a signal is received by the solenoid. The push button is depressed, which energises the solenoid and illuminates the LED, confirming that the primary key may be removed. Removal of the primary key changes the condition of the electrical supply to the machine to a safe condition. The primary and three secondary keys can then be used to unlock the interlocks on the access doors. The guards can only be opened once the electrical supply has been switched to a safe condition.

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