Handle follower

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Inside view of a mortise lock: the nut is the round part in the upper half.

A handle follower or lock follower is a component of locks. In the construction industry, it is mainly used in box and mortise locks for room doors or gates.

A square opening is integrated into the lock follower, through which a square is inserted. A door handle or a movable door knob ( handle ) sits on this square . The nut transmits the rotation from the square to a lever in the lock, which pulls the door latch back so that the door can be opened. Another lever with a suspended spring ensures that the door latch automatically moves back to its starting position. For doors in heavily frequented buildings such as B. Schools or universities, the lock nuts are mounted on ball bearings to reduce wear.

In panic locks with double-sided pusher a so-called "split nut" is used. Each handle set (inside and outside) has a separate square half, which transfers the rotary movement to one socket each. When locked, the outer follower is decoupled from the door latch so that the door cannot be opened via the outer handle. The handle can be pressed down, but the lock does not unlock. The inner handle, on the other hand, always remains in function regardless of the door's locking status and pulls both the lock bolt and the latch out of the frame.

In the German construction industry, a large number of standards describe the requirements and properties of various locks and building hardware. For example, DIN EN 12209 specifies a minimum reset torque for the nut. The square opening of the lock follower is also standardized. The side length of the square is between 8 mm for room doors and 9 mm or 10 mm for external doors.

Lock nuts are also used in door locks on automobiles. Especially in older vehicles without a remote-controlled locking system, lock nut switches were often integrated into the lock sockets, which controlled certain comfort functions or the activation and deactivation of the alarm system.

Individual evidence

  1. ↑ Lock nut - fittings - glossary - Baunetz_Wissen. In: baunetzwissen.de. Retrieved June 23, 2020 .
  2. ↑ Split nut - fittings - glossary - Baunetz_Wissen. In: baunetzwissen.de. Retrieved June 23, 2020 .
  3. ↑ DIN EN 12209 . Locks and building hardware - Mechanically operated locks and striking plates - Requirements and test methods. Beuth Verlag, October 2016, p. 14 .