Sidestepping interlocking devices remains a troubling issue
The defeating or manipulation of interlocking devices is still a common occurrence across many UK manufacturing sites. This can often leave machinery in an unsafe condition or facilitate access to areas of a machine that should be otherwise prohibited while it is in operation, cautions Euchner.
“In doing so, risk of significant injury to personnel is greatly increased and processes can also be prone to tampering or interruption; this disrupts productivity, introduces quality issues and often leads to unwanted costs,” says the company.
The standard EN ISO 14119 details how machinery shall be designed to reduce motivation to defeat interlocking devices and that the interlocking device should have minimal interference with the general operation of the machine to help reduce the incentive to defeat.
It is increasingly the machine designer’s responsibility to ensure this philosophy is put into practice, but often the ‘manipulation methods’ are uncovered by equipment users trying to increase production output or compensating for unreliable machinery.
To help machinery designers and users prevent one of the more common methods of overriding guard interlocks, Euchner offers the CES-A-BDN cylindrical actuator for its range of non-contact safety switches. The actuator measures only 6mm in diameter, with a length of 26mm – about the size of a small plastic screw-fixing – yet retains the long-range and high tolerances to misalignment associated with the Euchner non-contact switch range.
The compact design allows the actuator to sit within the framing of the machine door or even ‘potted’ within the acrylic panel itself, limiting both visibility and reachability when in use. “Due to this compact innovative design, the incentive and ease of defeating the interlock device by the user is significantly reduced, ensuring the machine will run safely and efficiently,” adds Euchner.
In addition to making the actuator difficult to identify, the solution provides a high coding level, creating a matched pair with the safety switch. “This prevents manipulation of the safety system through the use of an additional actuator.”
The CES-A-BDN actuator is also said to offer a high degree of ingress protection, rated at IP65/IP67, allowing it to be used in a multitude of environments, even where high levels of dust and moisture are present, including food processing, packaging, machine tools, beverage & brewing and dairy.