Materials handling vehicle mast height sensor

The present invention relates in general to materials handling vehicles and, more particularly, to a device for monitoring movement of mast elements of such vehicles so that the height of a mast, an associated load lifting device, an operator's platform or the like can be determined. A knurled wheel is coupled to a sensor mounted to one mast member and the wheel is forced into another mast member so that the wheel/sensor rotate upon mast movement. The sensor generates signals, corresponding to mast movement, which are processed conventionally to determine mast height, etc. The knurled wheel forms a track on the contacted mast member and the knurl engages the track. The wheel can be forced into the mast member with a force of six to nine pounds. To enhance the versatility of the mast height sensing device, the thickness of the wheel can be made less than inch, for example {fraction (1/16)} inch. The sensor can be an encoder or a sensor bearing and a heater can be provided for operation in cold environments to ensure rotation of the sensor under such conditions.