Abstract

A three-axis force measurement stylus includes a housing and a cartridge and an interface between the housing and the cartridge wherein the interface comprises a plurality of pressure sensitive sheets, preferably of variable resistance pressure sensitive Mylar films which sense the force between the cartridge and the housing. The cartridge and the housings are disposed at a skew angle relative to the axis of the stylus to be able to sense forces in three dimensions. In a specific embodiment, the cartridge forms a conical section which mates with a complimentary conical section of the housing. Membranes of the force sensitive material are provided along three fingers from an apex of the conical section. The cartridge is preloaded against the conical section by a spring between the housing and the cartridge. Alternatively to the force sensitive film, a sheet of a piezoelectric pressure-sensitive material may be substituted. In each instance, direct pressure between the conical section of the cartridge and the conical section of the housing is sensed by the sensor mounted therebetween.