Gear-type limit switches for crane hoists

S870 microswitches function as switching contacts in geared cam limit switches for Stromag AG.

The end positions of a crane lift correspond to rotary angles of the drive shaft. In geared cam limit switches for Stromag AG, the many rotations of the shaft are translated into rotary angles of a cam disc.

What task do the Schaltbau microswitches perform?

When the rotary angle of the lower operating position is reached, for example, the cam disc actuates a microswitch and the controller sends a signal to the cab: the crane operator stops the downward travel. But if he reacts too late and the rotary angle of the emergency end position is reached, the cam disc actuates another microswitch and the controller stops the drive automatically.

Why was the S870 chosen?
  • Compact and robust design, high shock and vibration resistance
  • Positive opening operation of the break contact (VDE approved)
  • Suitable for safety-relevant applications (Machinery Directive, ISO EN 13849)
  • Reliable thanks to self-cleaning contacts