Lock latch

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Painted oblique latch on an old door. The paint layer is worn where the latch has contact with the strike plate.
Mortise with reversible case top and bolt down
Simple lifting trap
Roll trap

The lock latch (also known as snapper ) is the part of a lock that holds a door in the strike plate after it has "fallen into the lock". The oblique trap, which is bevelled on one side, is common . When the door is closed, this runs along its bevel on the strike plate and is pushed into the door lock against the pressure of the latch spring . The latch keeps the door closed when the latch spring pushes it into the recess provided on the strike plate. Thus, the latch spring is the component of the lock that brings the latch back into its original position.

By operating the door handle (the "door handle") the latch is pulled out of the strike plate again and the door can be opened.

Some mortise locks allow the latch to be turned after opening the lock case. The lock can then be used with doors that open on the left or right (see illustration). The front edge of the retracted trap must not protrude more than one millimeter over the face of the faceplate . It can be provided with noise damping. If the latch of a door lock can be operated with the key, it is referred to as a change lock .

If a door is only closed by engaging the latch ( pulling or letting the door shut ), it can also be opened without operating the door handle by pushing the latch back with a tool or other aid. This can be prevented by complete or locking the door by the latch (usually by turning a key is pushed) in a recess provided at the strike plate. This type of protection is also the trap lock . It can also be retrofitted above and below the latch and acts like a bolt when closed.

In addition to the frequently used oblique traps, there are the following types of traps:

  • Roller latch - enables the door to be opened on both sides; is in swing doors used
  • Hook latch - is required to lock sliding doors that are moving frontally towards the stop
  • Lifting latch - traditional form of latch used in box locks ; the lifting latch usually engages in a locking bolt or a striking plate placed on the door frame
  • Crank latch - a variant of the oblique latch with a lever that can be moved into the latch and protrudes in the form of a tooth, which first hits the strike plate and pushes the latch into the lock with little noise. Crank latches are used on high-quality door locks. They require less maintenance and allow the door to close evenly without great effort.
  • Rotary latch - this type is mainly used on swing and folding doors of motor vehicles. In contrast to oblique latches, rotary latches engage in a striker or locking bolt and rotate in the process. Rotary latches are usually not self-locking. Most of the time, the pawls snap into place on the axis of rotation if the catch has twisted a little when it comes into contact with the locking bolt (striker). Two-stage locking is required for car doors: the door is locked securely with light pressure, and it is only pressed against the door seal when it is closed with greater pressure.
  • Whisper trap - a trap made of metal with plastic attachments that should allow the door to close quietly.

Traps can already be found in ancient Egyptian castles from the 3rd millennium BC.

See also

Individual evidence

  1. ↑ Lexicon of security technology. In: http://www.sicherheitstechnik.fermatec.de/ . Sicherheitstechnik Fermatek, accessed on February 11, 2020 .
  2. ↑ Baunetz Wissen - Sicherheitstechnik: Fallensperre. In: www.baunetzwissen.de. Baunetz Wissen - Glossary, accessed on February 11, 2020 .