Ziehfix
Ziehfix ( original spelling ZIEH-FIX® ) is a protected trademark of A. Wendt GmbH from Bergheim for a pulling tool available on the market that can be used to open doors in such a way that only the lock cylinder is destroyed. The fire brigade uses the tool to open emergency doors .
Working principle
With the help of a powerful cordless screwdriver, a special tension screw made of hardened material is screwed into the cylinder. The pulling tool is attached to this and the locking cylinder , which breaks apart at its weakest point due to the force acting, is pulled out. If the tool is used properly, the door usually remains undamaged, but the mortise lock is often bent in such a way that it has to be checked and, if necessary, replaced. The manufacturer therefore recommends the use of so-called core pulling plates. These hardened steel plates prevent the entire lock cylinder from breaking and only allow the cylinder core to be pulled out of the lock cylinder. The advantage of core pulling is that only the lock cylinder is damaged, but not the mortise lock.
There are locks that cannot be opened in this way for greater protection against burglary . A security fitting with core pulling protection (cylinder cover) mounted on a door can protect the profile cylinder and the mortise lock against unauthorized mechanical manipulation and prevents the cylinder from being pulled. There are also some high-quality locking cylinders on the market into which you cannot screw a lag screw in the first place, as the hardened steel elements in the cylinder destroy the thread of the lag screw.
Lag screws
Pull screws specially developed for opening the door are more important than the pulling device. A. Wendt GmbH also sells these under the brand name ZIEH-FIX ®. These lag screws consist of a special color marking and a trumpet head, which enables a good distribution of force. There are four versions that are used depending on the application:
- 4.2 mm, yellow: This lag screw is used for pre-drilling. This reduces the risk of the following screws breaking off.
- 4.8mm, turquoise: Used to break the cylinder apart.
- 5.5 mm, red: It is used to pull the core of a cylinder.
- M6 - blue: This lag screw was specially developed for the Swiss market.