For an interlocking safety device that offers reliability, durability and simplicity use the 440T Prosafe Trapped Key Safety Interlock Switch by Allen Bradley Guardmaster. This is a mechanical, industrial-grade solution for securing machine guards and providing essential protection for personnel. It ensures sequential access control, isolating the power supply to machinery when the gate or door is open.

The 440T-MSALE100A Prosafe trapped key access lock is single key and has a lever actuator. It is made of tough 316L stainless-steel to withstand harsh environments. It has an operating temperature of -40°C to +80°C. The primary function of this switch is to prevent unsafe access to hazardous areas where machinery may be in motion, posing a risk to personnel.

With Prosafe switches the new keys are fully compatible with old style barrels, however old keys do not fit the new barrels. The key must be trapped to release the lever. As the key is locked, the switch is ON and when the key is released, the switch is OFF.

This type of robust mechanical interlocking device is usually used in environments where electrical interlocking systems may be unsuitable or expensive to install and maintain, such as areas with explosive atmospheres.

• Direct drive operation
• Weatherproof stainless-steel dust cap
• Fitted with tamper resistant screws for improved security
• Robust 316 stainless steel construction for superior durability
• Replaceable and easy to clean code barrels for your convenience
• Ideal for sliding, hinged, and lift-off guards

EN292
EN1088
IEC 947-5-1
UL listed
CSA certified
IP20 rated

The Prosafe range of products have been extensively tested for quality and durability, working seamlessly for 100,000 operations. They are also highly tamper-resistant, accepting only the original or equivalent new key for operation. Allen Bradley Guardmaster have one of the broadest portfolios in the industry for machine monitoring and locking products, which ensures that you can create your ideal guarding system and keep your operations running smoothly.

A trapped key interlock is a simple sequential mechanical safety system for machine guards whereby a removable key is trapped in a control device while the power supply is running. Only when the power supply is turned off can the key can be rotated in the lock and withdrawn. While it is removed the power supply is isolated, ensuring that the machine cannot be restarted while the guard door is open. The key can then be used to release the machine guard, allowing access to the machinery. After the guard is closed it can be removed and inserted back into the original control unit, thus allowing the power supply to be activated again. Trapped key interlocks can withstand harsher environments than electrical interlocks and are often used in industrial settings where serious risk of injury can occur to machine operators.