Lexicon DIY-Knowledge

Protection against jamming, safety release clutch

Blockierungsschutz, -kupplung

Bloqueo, protección contra, embrague contra

Système anti-blocage

Impact drills can suddenly jam due to improper operation or use of wrong or blunt application tools. The same phenomenon can occur if the drill diameter is too large, if the core cutter is askew, or if hidden pipes or reinforcement steel are in your way. This can produce a sudden restoring torque which, especially if the operator does not have a firm foothold, is likely to cause accidents. A jaw clutch (square-tooth clutch) or a friction clutch can provide protection in this case since they disconnect the drive motor briefly from the drive spindle.

Built-in electronic control can also provide protection against overloading and jamming by reducing the operating voltage to a much lower motor voltage in the event of excessive power consumption. The machine stops, and normally the operator would immediately reduce the applied pressure. The low residual motor voltage is enough to restart the motor and to remove the dangerous blockage. The latter system is used mainly with angle grinders and portable circular saws.