Torque tests on car locking devices fitted with anti-theft systems

Cars are now being fitted to an increasing extent with central locking devices with integral anti-theft systems.

Cars are now being fitted to an increasing extent with central locking devices with integral anti-theft systems. In order to activate the anti-theft systems, the door key must be rotated against a resistance by an increased angle in the locking direction. Due to manufacturing tolerances the torque required can vary substantially, but should not exceed specified limits.

Normally, the lock cylinders are operated manually with the key to check that they can be turned easily. By their very nature, such tests are subjective, so that, for example, different opinions can arise between the manufacturer of the cylinder and the customer about whether the lock operates smoothly enough. Of course, it is possible to use normal measuring equipment to measure the torque required to rotate a lock cylinder in order to obtain objective measurements and equipment for the measurement of torque is commonly available.

However, the disadvantage with this equipment is the relatively complicated set-up which is not very suitable for the automatic testing of the cylinders in production.