Abstract: A precision measuring machine, such as a coordinate measuring machine, includes a probe assembly fixed to a movable member of the machine. The probe assembly includes a probe tip. A calibration object is detachably secured to the movable member in fixed relation to the probe assembly. The probe assembly articulates into a position such that the calibration object may be probed by the probe tip to recalibrate the probe assembly.

Abstract: The invention comprises a contacting block step gage in which the individual blocks are fastened together under extremely high compressive forces and any bending of the step gage is compensated for and in which the measuring surface is on the neutral axis of the gage and accessible via probe clearance channels in the blocks.

Abstract: The invention provides an electronic gage amplifier which converts sinusoidal signals representing measurement data from a gage head into a visual display of measurement data. The measurement signals are received by the amplifier at the input of a mixer where they are combined with a coarse adjustment signal. The coarse adjustment signal, which is provided by a multiplying digital-to-analog converter (MDAC) which is controlled by a microcomputer, yields a fine adjustment signal when mixed with the measurement signal. The resulting fine adjustment signal is amplified by a preamplifier, translated into a steady-state voltage by a programmable-gain demodulate-and-hold circuit (D/H) and converted to a digital word by an analog-to-digital converter (ADC). The microcomputer further causes a known reference signal to be processed through the MDAC, mixer, preamplifier, D/H, and ADC.

Abstract: Apparatus for counterbalancing a vertically movable element of a machine includes an air cylinder attached to the movable element on the axis of movement and having a small axial opening at its upper end. A piston located in the air cylinder is attached to a fixed machine element by a nonelastic, flexible member such as a thin, nylon-jacketed wire passing through the axial opening in the cylinder. Air under pressure sufficient to counterbalance the weight of the movable element is supplied to the space between the piston and the axial opening in the cylinder. The flexible member makes the counterbalancing assembly relatively insensitive to misalignment and vibration. Air is permitted to leak around the piston to reduce friction and to relieve pressure buildup during downward movement. In another embodiment, the air cylinder is attached to the fixed machine element.

Abstract: A method and apparatus provides a three dimensional measurement of a point on an object. A surface with a system for detecting the position of sensors is placed adjacent to the surface and an assembly disposed adjacent to the surface yet freely movable within a plane is parallel to the surface. The assembly includes two sensors whose orthogonal projections into the surfce are detected by the two dimensional detecting system. The assembly further includes a probe, slidable only in a direction perpendicular to the surface and a system for detecting the perpendicular distance of the probe from the surface. In this manner, the orthogonal projection of the probe into the plane is permanently fixed in relation to the two sensors. In practicing the method of the invention, the object to be measured is placed adjacent to the surface and the assembly is moved to a position where the contact on the probe can be moved orthogonally until it contacts the spot on the object whose position is to be measured.

Abstract: In a coordinate measuring machine, apparatus for compensating the sensing means for determining the position of a probe for changes in temperature, where the machine base and the support column for the probe have differing coefficients of thermal expansion. In a preferred embodiment, the apparatus of this invention is used to prevent "zero shift" in the Z-direction for a Z-rail. The compensating apparatus is associated either with the support column or Z-rail. The apparatus offsets the greater expansion of the machine component having the greater coefficient of thermal expansion. Typically, the position sensing means for the Z-rail includes an encoder and a scale. In one embodiment, either the encoder or the scale is secured to a mount which is affixed to the column. One element of the mount which extends upwardly from the support column has a coefficient of thermal expansion which is substantially less than that of the aluminum of which the column is composed.