Patent ID: 6591688
Filing Date: 2003-07-15
Classification: G01F,G01L

Abstract:
A load transducer comprising:A) a load cell including: i) a high-permeability path material forming an at least partially saturable high-permeability path portion of a closed magnetic path in which the high-permeability portion is interrupted by a relatively low-permeability path portion shorter than the high-permeability portion; ii) a permanent magnet generally aligned with the path and mounted in the low-permeability path portion for such resilient relative movement between the magnet and at least part of the high-permeability path portion upon application of load to the load cell as to change the degree of magnetic saturation of the magnetic path, the total length of the low-permeability path portion, exclusive of the magnet, being less than four times the thickness of the magnet in the path direction; and iii) an electrically conductive coil so linked to the magnetic path that the inductance of the coil depends on the reluctance of the magnetic path, whereby the inductance of the coil depends on the load applied to the load cell; and B) an inductance-to-load converter, connected to the coil, that measures a coil-inductance-dependent quantity, determines the load from the coil-inductance-dependent quantity, and generates an output indicative of the load thereby determined.