Stylus probe for measuring workpiece surface characteristics

In a stylus probe for a co-ordinate measurement machine, said machine including a multiple axis carriage, said probe adapted to be carried on said carriage for determining surface topography information about an associated workpiece, wherein the improvement comprises:

• (a) an elongated stylus probe means formed of a rigid, elongated, hollow tubular member with a connecting-end and a tip-end;
• (b) a mounting means for mounting said connecting-end of said stylus probe means to said multiple axis carriage of said co-ordinate measurement machine;
• (c) a capacitive sensor means for measuring capacitance between said probe and a topographical feature of an associated workpiece, said sensor mounted on said tip-end of said stylus probe;
• (d) a conductive lead wire connecting said capacitive sensor means, said wire conductively secured to said sensor means and extending through said probe to the co-ordinate measurement machine.
• (e) a means for shielding said conductive lead wire from environmental influences of temperature, atmosphere, humidity and external electrical noise, said means for shielding comprised of a metal foil wrapping within a non-conductive container.
• (f) a means for applying a voltage across said workpiece and said capacitive sensor means;
• and
• (g) a means connected to said lead wire for measuring capacitance effected across said workpiece and said capacitive sensor means.

In a stylus probe for a co-ordinate measurement machine, said machine including a multiple axis carriage, said probe adapted to be carried on said carriage for determining surface topography information about an associated workpiece, wherein the improvement comprises:

• (a) an elongated stylus probe means formed of a rigid, elongated, hollow tubular member with a connecting-end and a tip-end;
• (b) a mounting means for mounting said connecting-end of said stylus probe means to said multiple axis carriage of said co-ordinate measurement machine;
• (c) a capacitive sensor means for measuring capacitance between said probe and a topographical feature of an associated workpiece, said sensor mounted on said tip-end of said stylus probe;
• (d) a conductive lead wire connecting said capacitive sensor means, said wire conductively secured to said sensor means and extending through said probe to the co-ordinate measurement machine.
• (e) a means for measuring environmental capacitance, said measuring means connected adjacent to said tip-end of said stylus probe;
• (f) a means for subtracting a value of said environmental capacitance from a capacitance value of said capacitive sensor means.

In a stylus probe for a co-ordinate measurement machine, said machine including a multiple axis carriage, said probe adapted to be carried on said carriage for determining surface topography information about an associated workpiece, wherein the improvement comprises:

• (a) an elongated stylus probe means formed of a rigid, elongated, hollow tubular member with a connecting-end and a tip-end;
• (b) a mounting means for mounting said connecting-end of said stylus probe to said multiple axis carriage of said co-ordinate measurement machine;
• (c) an elastomer material positioned against and between said mounting means and said tubular member at said connecting-end portion of said probe, said elastomer being compressed by deflection of said probe and then rebounding, thus having a dampening effect on vibrations of said probe.
• (d) said elastomer further comprising a first segment and a second segment, said segments placed in annular contact with said mounting means and said tubular member, said first and second segments axially separated, said first segment more proximally located to said connecting-end.