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"Designer" safety switch aids machine downsizing

A Rockwell Automation - Allen-Bradley Guardmaster product story

Edited by the Engineeringtalk editorial team Dec 10, 2003

All the key designer benefits of small size, high holding force and robust metal construction are provided by Guardmaster's new 440G-MT solenoid locking switch.

All the key designer benefits of small size, high holding force and robust metal construction are provided by Guardmaster's new 440G-MT solenoid locking switch.

The 440G-MT is a new generation safety device that enables designers to respond positively to the pressures of downsizing with modern machinery.

At the same time it provides improved safety provision with a substantial 1600N of holding force to ensure that guard doors stay firmly shut until machine power is isolated.

The slim design of the 440G-MT (to DIN500491), together with its flexibility for eight actuator entry positions, enables the new safety interlock to be mounted on most designs of guards, even in tight spaces.

Moreover, the combination of the 440G-MT's robust metal body and its flexible actuator - which allows for the effects of guard wear, mean that it is the ideal device for use in a widest range of operating environments, including arduous ones where lower temperatures (down to -25C) and external atmospheric conditions are encountered.

With its extremely high holding force, the GM 440G-MT provides a solution across a greater range of applications where higher actuator holding forces are required.

For the designer and OEM this means a reduction in inventory as only a single type of switch, rather than a range of switches need be stocked.

Also aiding stock reduction, the inline symmetrical head design of the 440G-MT means that the safety interlock can be used on both left and right handed guard door applications.

In contrast, competitive units without this feature may require several discrete handed versions to be stocked.

The 440G-MT is available in four basic versions providing the OEM with the maximum choice of operating configurations, including power to release or lock, optional arm key release and LED indication, if required.

Standard across all these versions is the facility for operation in high risk applications, the 440G-MT being designed with four sets of contacts, which can be configured in a number of ways: 4NC, 3NC/1NO or 2NC/2NO.

These contact options provide great flexibility to the OEM as, once again, they can reduce the number and type of safety switches required on a machine.

In addition, they are also part of an electrical installation package that makes the 440G-MT easy to install.

The second element in the package is three conduit entry options, which allow cable entry on either side of the safety interlock, or at the end of the unit.

All versions of the 440G-MT conform to standards EN1088, EN60947-5-1 and IEC60204 -1, with both TUV and UL approvals pending.

The interlocks are suitable for operation on 24V (AC and DC), 110V AC and 230V AC supplies and are rated for operation in the temperature range -25 to +80C.