Abstract: A coordinate measuring machine (10) having a pneumatic probe counterbalance system housed within the probe shaft (14) is disclosed, the system including a piston (54) fit into a cylinder (30) extending along the length of the probe shaft (14). The piston (54) is fixed so that air pressure acts on a cylinder end cap (32) to counterbalance the weight of the probe assembly (12). A stationary tube (34) extends into the cylinder (30) from above the piston (54) and directs a source of regulated air pressure to the cylinder interior (58) from a fluid pressure fitting (48) connected to the upper end of the tube (34). The piston (54) is at least partially spherically shaped and the tube (34) is supported by a spherical bearing (42) to accommodate misalignment of the tube (34) and cylinder (30) without binding during movement of the probe shaft (14). A length of wire (56) is connected at one end to the piston (54) and extends upwardly through the tube (34), and is fixed at its upper end to anchor the piston (54).

Abstract: A coordinate measuring machine (10) having a light weight aluminum bridge (24) mounted for guided movement along ways (42) on a base (28), which also is constructed of aluminum to match thermal growth characteristics of the bridge (24). The table (12) is constructed of steel for greater rigidity to support heavy measured objects (1b) and is supported on the base (28) so as to minimize distortions of the base (28) by differences in thermal growth of the table (12), and base (28). The weight of the table (12) and measured object (16) is arranged to be passed through the base (12) to floor supports (62, 112) to minimize distortions of the base (12) and ways (42). The bridge (24) is movable completely to the rear of the table (12) to enable access of the probe (18) to the total table surface area FIG. 2.

Abstract: A coordinate measuring machine (10) is disclosed of the type having a bridge (28) mounted for horizontal movement of a base (30), a carriage (24) mounted for horizontal movement in a direction orthogonal to the direction of bridge movement and a probe (12) mounted for vertical movement on the carriage (24), so that the probe (12) is guided along three orthogonal axes over a table (14) supported on a base (30), so as to enable measurement of an object (16) disposed on the table (14) by measuring the extent of travel along each axis. Side covers (42, 50) are provided fastened to the base (30) and enclose the lower ends of upright members (40) comprising in part the bridge (28) so that the bridge (28) movement is confined within openings (44) formed by the side covers (42, 50). A dust covering movable belt (46)is attached at either end to each upright member (40), closing off the openings (44 ), the belt (44) recirculating as the bridge moves.

Abstract: A coordinate measuring machine (10) having a vertically movable probe (41) supported from the bottom of a probe arm (42), the weight of which is offset by an improved pneumatic counterbalance (50). The pneumatic counterbalance is adapted to use a source of pressurized air acting upon a spherical piston (54) which is connected to probe arm (42). Spherical piston (54) fits with a close tolerance in cylinder (52). A rigid bracket (58) is connected to the top of probe arm (42). Piston rod (56) connects spherical piston (54) to a spherical bearing (53) in rigid bracket (58). A precision pressure regulator (70) having a relatively small capacity is provided to insure only a small change in the counterbalance force as the spherical piston (54) moves within cylinder (52). Regulator (70) is adjusted to provide make up air for the air which leaks past spherical piston (54).

Abstract: A coordinate measuring machine having a vertically movable probe shaft in which a vertical fine feed and lock mechanism for the probe shaft is provided by a first knob coupled to a magnet movable between two positions, one of said positions operatively coupling a second knob to the probe shaft for driving said probe shaft in a vertical direction, the other of said positions being ineffective for moving the fine feed mechanism. The fine feed is accomplished through the rotation of a second knob which is in frictional engagement through a driven quasi "V" shaped flanged wheel with the probe shaft to be moved vertically.

Abstract: A coordinate measuring machine for measuring parts using cylindrical coordinates. The machine includes a base, an articulated arm mounted to the base at its proximate end for movement within a plane, and a vertically movable probe assembly mounted near the distal end of the articulated arm. A horizontal measuring rod extends between the distal end of the arm and the base to provide a measurement of the location of the probe with respect to the base, in terms of a radius and an angular displacement. The probe assembly includes means for measuring perpendicular displacement of the probe from the plane of the articulated arm.

Abstract: A coordinate measuring machine having an automatic failsafe protection system. The coordinate measuring machine (10) includes a vertically mounted probe shaft (42) which is preferably counterbalanced by an air counterbalance system (100). The automatic failsafe protection system (200) insures that, in response to a loss of air pressure (or in response to other possibly unsafe conditions), the vertically-mounted, air-counterbalanced probe shaft (42) will be prevented from falling down uncontrollably. The failsafe protection system (200) includes a pair of members (230, 240), with each member mounted adjacent to and on opposite sides of the probe shaft (42) and urged toward engagement with probe shaft by a spring (250). Air under pressure from an air cylinder (210) also acts upon the members (230, 240) to bias the members outwardly away from engagement with the shaft when normal (i.e. safe) operating conditions exist.

Abstract: A coordinate measuring machine (10) having a vertically mounted probe (32), the weight of which is offset by an air counterbalance system (100). The air counterbalance system is adapted to use a source of air under pressure acting upon a piston (127) coupled to the vertically mounted probe (42). A torque converter (130) is mounted between the probe (42) and the piston (127) allowing the piston (127) to have a shorter travel than the allowable vertical travel of the probe (42). The air counterbalance system (100) preferably has components selected and arranged to minimize friction and weight to avoid distorting the precision of measurements on the coordinate measurement machine.