Patent ID: 7259553
Filing Date: 2007-08-21
Classification: F15B,G01D

Abstract:
1. A position-sensing system, comprising: a cylinder; a piston rod movably coupled to the cylinder for movement with respect thereto; a magnetically hard layer formed on the piston rod to provide a recording medium, a plurality of regions of the magnetically hard layer being magnetized to provide an encoding scheme for determining a position of the piston rod relative to the cylinder; and a plurality of magnetic-field sensors coupled to the cylinder in proximity of the magnetically hard layer to sense the magnetized regions while the piston rod is moving with respect to the cylinder, at least two of the magnetic-field sensors being axially positioned to sense the same set of magnetized regions in succession and to generate signals in response to the sensed magnetized regions that can be used to determine a position of the piston rod.