Coordinate measuring machine

A coordinate measuring machine (CMM) comprising:

• a base;
• two Y-axis beams affixed to the base;
• an X-axis beam extending between the Y-axis beams;
• a Z-axis carriage for supporting a probe shaft assembly on the X-axis beam;
• and
• a combined Z-axis counterbalance and drive means including a counterbalance assembly for counterbalancing the weight of the Z-axis probe shaft assembly, and including a drive assembly for driving the Z-axis probe shaft assembly and the counterbalance assembly with a single motor;
• wherein the combined Z-axis counterbalance and drive means further includes:
• a flexible cable attached to the probe shaft assembly;
• a spring-powered take-up reel for coiling the cable and for counteracting the weight of the probe shaft assembly;
• and
• a reversible DC servo motor configured to rotate the take-up reel in accordance with the desired amount of Z-axis movement of the probe shaft assembly.

A coordinate measuring machine (CMM) comprising:

• a base;
• two Y-axis beams coupled to the base, one Y-axis beam including a Y-axis drive screw;
• an X-axis beam extending between the Y-axis beams;
• a Z-axis carriage for supporting a probe shaft assembly on the X-axis beam;
• and
• means for coupling the X-axis beam to the Y-axis drive screw such that a variable amount of angular alignment compensation is provided between the X-axis beam and the Y-axis drive screw.

A coordinate measuring machine (CMM) comprising:

• a monolithic gantry-style base constructed of a polymer composite and having two individual pillars;
• a Y-axis beam disposed on each pillar, one Y-axis beam including a Y-axis drive screw;
• an X-axis beam extending between the Y-axis beams, the X-axis beam disposed on only three bearings configured to provide a three-point support on the Y-axis beams, wherein the X-axis beam is disposed on two bearings on a first Y-axis beam and only a single bearing on a second Y-axis beam, and wherein the single bearing is compliantly mounted between the X-axis beam and the second Y-axis beam such that the single bearing is permitted to move at least in the X-axis direction while providing stiffness in the Z-axis direction;
• means for coupling the X-axis beam to the Y-axis drive screw such that a variable amount of angular alignment compensation is provided between the X-axis beam and the Y-axis drive screw;
• a Z-axis carriage for supporting a probe shaft assembly on the X-axis beam;
• and
• a combined Z-axis counterbalance and drive means including a counterbalance assembly for counterbalancing the weight of the Z-axis probe shaft assembly, and including a drive assembly for driving the Z-axis probe shaft assembly and the counterbalance assembly with a single motor.