Rockwell Automation is promoting the stainless steel version of its Allen-Bradley Guardmaster Lifeline 4 cable pull switch, designed for applications where hygiene and/or corrosion resistance are essential requirements. The 316-bodied Lifeline 4 is suitable for both internal and external use, providing users with emergency stop access along exposed conveyors and around awkward machinery. The Stainless steel Lifeline 4 is said to be one of the only investment cast stainless steel cable pull switches of its type on the market.
Based on the proven technology of the standard Lifeline 4, the stainless steel version can be used in hygiene-conscious industries, such as food and beverage, as well as industries such as quarrying and mining, paper production and automotive where corrosion can be a major problem. The robust and cost-effective emergency stop provision delivered by the stainless steel Lifeline 4 is not only intended to help with worker safety, but also to reduce disruption to production caused as a result of corroded cable pull switches.
The stainless steel Lifeline 4 is sealed to IP66/IP67, making it suitable for use in washdown environments. Furthermore, the robust body is unpainted and all markings are laser etched so that they cannot flake or rub off. The seal between the lid and the body protrudes slightly, preventing it from acting as a food trap, and raised pads on the switch base allow washdown water to circulate freely around the switch, so that product residues do not become trapped.
Nuisance trips minimised
Complementing these external design features is an operating mechanism that delivers positive, immediate latched operation in response to a definite deflection. It also minimises nuisance tripping and the effects of thermal expansion.
The positive-mode operation is one of several major features that make the unit one of the most versatile cable-operated safety switches on the market. In addition to its integrated cable status indicator and four sets of contacts (two normally-closed and two normally-open), it also includes a switch lockout and a lid-mounted, mushroom-headed EN 418-compliant emergency stop button that provides an additional E-stop facility at the extreme ends of the cable span.
In common with all products in the Lifeline range, the stainless steel Lifeline 4 is easy to set-up and maintain. It can be mounted in any orientation using a combination of its stainless steel installation kit and the integrated cable status indicator. When correctly installed, a pair of switches serve a safety grab wire up to 75m in length. This large span helps to reduce the number of emergency stop buttons required to offer adequate protection in applications such as conveyors, while also providing a tripping facility for effecting machine shutdowns and lockouts if an operator should fall or is pushed against the cable.
Suitable for OEM use, the stainless steel Lifeline 4 is consistent with the requirements of EN 418 'Safety of Machinery - Emergency Stop Equipment' and addresses ISO TR 12100, ISO 13850, EN 60947-5-5 and IEC 60947-5-1 standards. The product is also CE marked as well as having cULus and TUV approvals.