Patent ID: 7036233

Claim:
A mechanical pivot linkage for coupling together first and second components of heavy machinery, the pivot linkage allowing relative rotational and linear movement between the first and second components, said mechanical pivot linkage comprising: a first linkage joint member coupled to said first component; a second linkage joint member coupled to second component, said second linkage joint member adapted to be mounted on said first linkage joint member in mating engagement with said first linkage joint member, allowing at least relative rotational movement; and a non-contact, rotational angle measurement sensor for measuring the rotational angle between said first and second linkage joint members, and thus, said first and second components, said angle measurement sensor including one or more permanent magnets carried by said first linkage joint member and a magnetoresistive sensor carried by said second linkage joint member, said magnetoresistive sensor having a surface, and said one or more permanent magnets defining a planar surface overlying said surface of said magnetoresistive sensor and spaced apart from said surface of said magnetoresistive sensor, wherein the strength of said one or more permanent magnets and the spacing “d” between the planar surface of the permanent magnets and the surface of the magnetoresistive sensor are selected to produce a magnetic field that causes said magnetoresistive sensor to operate in a saturated condition, so that said non-contact, rotational angle measurement sensor detects only changes in the direction of the magnetic field strength, indicative of relative rotational movement between the first and second components, while remaining insensitive to relative linear movement between said first and second components.