TWO HEADS ARE BETTER THAN ONE FOR ACCESS DOORS

Phil Black - PII Editor 17/04/2008

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The latest developments from the safety specialists Euchner include twin-headed switches designed for use with two adjacent machine access or cell enclosure guards. Previously, it would have been necessary to use two separate switches for this purpose, involving not only additional material costs, but also extra control circuitry and monitoring facilities.

The new switches are double-headed versions of their well proven STP and SGP safety switches, having an established combination of plastic housings with robust metal actuating heads and internal cams which are suitable for demanding applications involving high locking forces (up to 2500N).

The use of a single safety switch for the control of two guards or doors has obvious cost cutting advantages. The doors can be hinged or sliding varieties, and typically would be used where a machining cell is located alongside and associated preparation, loading or even palletising enclosure. Controlled access to either station can be maintained for purposes of safety during production, inspection, cleaning or general maintenance procedures.

Two switches are available including the SGP Twin which is supplied without guard locking. Manual padlocking is available, however, to ensure the switch actuators cannot be removed from the switch head. The second switch is the STP Twin which incorporates guard locking, an independently operated electronic shot-bolt mechanism which can be key operated or automatically released when a monitored machine has stopped or is otherwise safe. The mechanical key release feature can be used as a lockout for the guard locking function to prevent unintentional guard locking. This ensures that personnel are not trapped within a machining or production cell if a safety door is accidentally closed.

Both switches have the same drilling patterns for fixing and are provided with three cable entry options for maximum mounting flexibility. Optional LED indication showing the door and solenoid positions is available for the STP Twin switch. Both products are supplied with various contact combinations (positively driven NC/NO contacts), and it is possible to achieve the highest safety level with a dual-channel wiring system. With a 1mA minimal switching current, they can also be used with safety control relays and safety PLCs.

The switches also provide an IP67 degree of protection and the straight actuators are suitable for all applications including a door radius up to 300mm.

For more information contact Euchner (UK) Ltd, Sheffield, South Yorkshire

Tel: 0114 256 0123 Fax: 0114 242 5333

E-mail: info@euchner.co.uk Web: www.euchner.com