Roller position monitoring device for an industrial lift truck

An industrial lift truck, comprising:

• a load lifting device;
• a device for moving the load lifting device on the lift truck and having at least one element that can move, together with the load lifting device, along a substantially straight guide;
• a position measuring device for monitoring the relative position to the guide of the element movable with the load lifting device or of the load lifting device;
• said position measuring device including at least one roller body which, when the element that is movable with the load lifting device moves, executes a rotary motion and acts in combination with a sensor which transmits an electric signal as a function of the rotational movement of the roller body to an analysis circuit which evaluates the signal to determine the position of the element that is movable with the load lifting device, or the position of the load carrier, relative to the guide;
• and
• said roller body being part of a roller bearing or mounted by means of a roller bearing so as to be rotatable and being arranged on the element that is movable with the load lifting device such that it is capable of rotation and its circumference contacts a path running along the guide in such a way that it is forced to roll along the path by movement of the element that is movable with the load lifting device along the guide.