According to the European standard EN ISO14119, doors, flaps, and covers that must be closed during operation of a machine must be secured with locking devices. Accordingly, safety switches are widely used in production plants, for example, to protect machine tools. Safety switches with and without guard locking are available depending on the requirements. In most safety switches with guard locking, electromagnets are applied.
The electromagnet assumes the task of holding a latch bolt (mounted on the door) in the engaged state. A linear movement of a linear solenoid in the safety switch (mounted on the door frame) fixes the bolt in the protective position. With the monostable design, the locking device is brought into the locked position by a spring and unlocked through an electrical signal to an integrated linear solenoid. In the bistable design, both locking and unlocking are controlled by the energy supply without any spring force.
Holding solenoid systems are also increasingly being used for guard locking in safety switches. By applying current in the closed state, extremely high magnetic holding forces prevent the opening of the protective device. For this purpose, the holding solenoid is mounted on the moving part of the protective device (door) and an armature plate on the fixed part (door frame). To achieve an extremely high resistance against media or wear, the holding magnets from Kendrion have a special coating. The use of holding magnets is advantageous if safety switches are exposed to high levels of contamination due to environmental conditions.
Kendrion uses extremely reliable linear solenoids and holding solenoid systems for the high demands in the field of process and personal protection. Kendrion guarantees six million or more switching cycles for the electromagnets. In addition, high lifting or holding forces are realized in the smallest installation space, whereby, for example, locking forces of up to 6,500 N can be achieved.
Thanks to our many years of experience in the field of safety switches, we can develop optimum solutions together with our customers. In the production of electromagnets, we also strive for zero-defect manufacturing despite a high proportion of manual work steps.