SYSTEM FOR MEASURING LENGTH OF A BEAM EXTENSION AND DETECTING SUPPORT

摘要

An extendable beam measurement system includes a support; a beam mounted on the support and movable with respect to the support along an axis of movement; a series of sensory points mounted along either the beam or the support in an orientation that is not parallel to the axis of movement of the beam; and a sensor attached to the other of the beam or the support in a direction that crosses the series of sensory points at different positions during movement of the beam along said axis. The sensor generates a first signal varying as the beam is moved along the axis to thereby provide a signal indicating the position of the beam with respect to the support. The system is useful on an outrigger for supporting a crane. Optionally the system can provide a second signal indicative of whether a jack on the outrigger is contacting a support surface and supporting the crane. Alternatively, the system used to optionally generate the second signal can be used by itself to indicate whether a jack is supporting the crane, even if the beam extension is not measured.