Multicoordinate sensing head

Claim 1

In a sensing head adapted to be mounted to a measuring or processing machine, said sensing head comprising a casing and a sensing pin having a sensing end and a mounting end, the improvement comprising: means, included in the casing, for allowing the mounting end to move along a predetermined axial direction while constraining the mounting end of the sensing pin against radial movement perpendicular to said axial direction; a first, rotationally symmetric element mounted to the sensing pin at a point intermediate of the sensing end and the mounting end; a second element included in the casing adjacent the first element, said second element shaped to bear against the first element in order to center the sensing end of the sensing pin in a predetermined rest position in the absence of radial forces on the sensing end and to cause the mounting end of the sensing pin to move along the axial direction in response to radial deflection of the sensing end of the sensing pin; and means, mounted adjacent the mounting end of the sensing pin, for sensing the axial position of the mounting end of the sensing pin and for generating a deflection signal in response thereto; said first element mounted to the sensing pin comprising a truncated cone and said second element included in the casing comprising a torus defining a central opening sized to receive the sensing pin, said torus shaped to surround and contact the truncated cone to center the sensing pin.