Abstract: A height control system is disclosed for use on a harvester and includes at least one lightweight wheel which rides over the crop being harvested at a location forwardly of the vehicle in an undisturbed area of the crop without damaging the crop. The wheel detects upward or downward inclined portions of the ground and controls power means which raises or lowers at least one plant handling component of the harvester for maintaining the component at the desired elevation relative to the ground. The system also includes control means which sense varying ground speed and prevents undesirable jerky raising and lowering of the conveying components in response to the wheel riding over small articles such as rocks at different speeds.

Abstract: Apparatus for detecting changes in inclination or acceleration is disclosed. In its preferred environment the apparatus is used to determine the position of the sucker-rod of a sucker-rod pump. The preferred embodiment of the apparatus includes a magnetic-field sensor such as a linear output transducer which provides a linear output signal, and a cantilever spring having a counterweight and magnet on its free end disposed adjacent the linear transducer. Oscillation of the walking beam of the pump causes the spring supported magnet to move relative to the sensor producing linear output signals which are processed by other means to determine the position of the sucker-rod at all times. The apparatus may be used in other environments to determine either changes in inclination or changes in acceleration.