Side supports against tipping over are installed for lift trucks and lift work platforms. The crane or the platform can only be put into operation when the supports are completely extended so that there is also no danger of tipping in the case of long extension frames. However, sometimes this is not possible for spatial reasons. Therefore draw-wire sensors from Micro-Epsilon are used for measuring how far the supports are extended. A dynamic load torque limit across the actual support area is thus produced. Redundant measurement is performed as this is a safety relevant measured value.