Position monitoring system

摘要

An apparatus for monitoring displacement of an object over time is provided, which comprises a contact point 11 for contacting the object (railway sleeper 13) being monitored and means (in casing 9) for converting movement of the contact point in response to displacement of the object being monitored into a corresponding rotational movement (via pulley wheel means 31) . The rotational movement is then measured to generate a signal indicative of the displacement of the object see magnet 53 and Hall effect chip 27 (figures 2, 4 and 5).