EUCHNER TX1B-A024M Guard Locking Safety Switch

Slim metal safety switch with spring-applied guard locking

The EUCHNER TX1B-A024M (order no. 082921) is an electromechanical safety switch with guard locking from the TX series. It is built in a narrow die-cast alloy housing, which makes it easy to mount on the profiles of guard fences, and it holds a door closed with a maximum locking force of 1700 N (FZh 1300 N). Guard locking uses the closed-circuit current principle: a spring locks the bolt, and the 24 V solenoid must be energised to release it, so a power failure leaves the guard locked.

Unlike the transponder-coded switches in the EUCHNER range, this device uses a mechanical actuator and slow-action contacts. The switching element is ETX B, with one NC contact for door monitoring and, for guard-lock monitoring, two positively driven contacts plus one NO contact. Two freely assignable LEDs (red and green) show status, and the head can be turned in 90° steps for horizontal or vertical approach.

Technical specifications

Actuators, releases and TX variants

The actuator is not included. EUCHNER lists stainless-steel actuators for the NX/TX series: BETAETIGER-X-GQ (straight, 079739), BETAETIGER-X-GNQ (increased overtravel, 079741), BETAETIGER-X-WQ (bent, 079740), BETAETIGER-X-WNQ (bent, increased overtravel, 079742) and hinged actuators RADIUSBETAETIGER-X-LR-N and RADIUSBETAETIGER-X-OU-N. Overtravel is 8 mm with the GNQ type and 1 mm with the GQ type.

The auxiliary release on the front lets a trained person unlock the guard with a tool or key during a fault; it must be protected against misuse, for example with a lead seal kit (087256). Options include an emergency release with manual return (094771), a lockout bar for padlocks (096098) and metal bolts for right- or left-hinged doors. The TX1B-A024 line is also listed with NPT 1/2 in cable entries, M12 or M23 plug connectors and an ASi version.

Application notes

Guard locking on a spring-locked switch suits machines with run-down motion, where a door must stay shut until the hazard has stopped. The locking control is external, so the achievable performance level depends on how the solenoid is controlled. Evaluate the door monitoring and guard-lock contacts in a suitable safety relay or controller.

Documents and quotation

The EUCHNER operating instructions for the TX series, available from the official product page linked below, cover mounting, wiring and the release functions. For a quotation, provide the order number 082921, the actuator type, accessories and the quantity. Related interlocks are under Safety Switches and Guard Locking.

How the TX1B-A024M guard locking works

When the guard is closed, the TX1B-A024M actuator enters the head and moves the internal cam. The door monitoring contact changes state, and the spring then pushes the locking bolt into the actuator. Only when the bolt is fully engaged do the positively driven guard-lock monitoring contacts close, so the safety circuit can tell the difference between “door closed” and “door closed and locked”. To open the guard, the control system applies 24 V to the solenoid, the bolt is withdrawn and the guard-lock contacts open before the actuator can be pulled out. Positively driven contacts are forced open mechanically, so a welded contact cannot hide an open guard.

Slow-action contacts switch in proportion to the actuator movement. That is why EUCHNER specifies a minimum switching load and gold-flashed silver contacts: the switch is suited to low-level safety relay inputs as well as to 230 V AC control circuits within its utilization category.

Selection checklist for the TX1B-A024M

• Confirm 24 V AC/DC solenoid supply and the power-to-unlock principle suit the machine.
• Choose the actuator for the door type: straight or bent for sliding doors, hinged radius actuators for small door radii.
• Decide whether an emergency release or a lockout bar is required.
• Check cable entry type (M20 x 1.5 on this variant) and the gland sizes needed.
• Select a safety relay or safe controller that monitors both the door and guard-lock contacts.

Installation and maintenance

Mount the switch on a flat surface and fit the actuator so it enters the head centrally; do not use the switch or actuator as a door stop. Turn the head to the required approach direction before tightening. Use cable glands matching the M20 x 1.5 entries to keep IP67 protection. After installation, check that the guard cannot be opened while locked and that the auxiliary release works. Seal the auxiliary release after commissioning. Periodically inspect for wear on the actuator, loose screws and damaged cables, and repeat the functional test after any repair.

Typical applications in Oman and the GCC

The die-cast housing and wide temperature range make the TX1B-A024M suitable for machine tools, presses, robot cells, packaging machines and heavy guard doors in hot workshops and outdoor-adjacent plant areas.

Why source from Seven Star LLC

Seven Star LLC supplies EUCHNER interlocks, actuators and accessories across Oman and the GCC. Our team can help confirm the correct ordering code and actuator before you request a quote.