Abstract: A coordinate measurement machine (CMM) includes a manually-positionable articulated arm. The articulated arm includes arm segments and rotary joints. At least one of the rotary joints includes a bearing assembly that comprises first and second bearings, a shaft that engages an inner race of the first bearing and an inner race of the second bearing, a housing that engages an outer race of the first bearing and an outer race of the second bearing, and a transducer configured to output an angle signal corresponding to an angle of rotation of the shaft relative to the housing. The shaft and the housing may be fabricated from materials having coefficients of thermal expansion selected to minimize change in moment rigidity and/or radial rigidity of the bearing assembly as the ambient temperature changes from the lower limit to the upper limit of the CMM operating ambient temperature range.

Abstract: A length reference bar system and method that compensates for thermal expansion and allows for testing whether an instrument is working properly using only an inferometer. The system has a bar portion with end caps for target positions on either end of the bar portion that extend inward toward each other such that, if a length of the bar portion changes due to a temperature change, a length of the end caps also changes in an opposite direction to counteract the bar portion length change. Any target positions mounted on the end caps remain at a constant distance from each other regardless of the temperature thereby canceling out the effect of thermal expansion. The end caps also provide multiple target positioning capability so that any targets mounted thereon may be positioned in various configurations to provide a user with increased versatility for applications such as checking calibration.

Abstract: Disclosed is a micrometer with an improved a heat-insulating property. A micrometer 10 with a U-shaped frame 20 supporting an anvil 12 and a spindle 14 at tip end portions thereof so that the anvil 12 and the spindle 14 are coaxially opposed to each other is provided with a heat insulating cover 50. The heat insulating cover 50 is shaped to accommodate a bottom portion of the frame 20, and is detachable with respect to the frame 20. The heat insulating cover 50 covers a bottom face 22 of the frame 20 while supporting the bottom portion of the frame 20 by sandwiching from both sides of the frame 20.

Abstract: A length reference bar system and method that compensates for thermal expansion and allows for testing whether an instrument is working properly using only an inferometer. The length reference bar system has a bar portion with end caps for target positions on either end of the bar portion that extend inward toward each other such that, if a length of the bar portion changes due to a temperature change, a length of the end caps also changes but in an opposite direction to counteract the bar portion length change. As such, any target positions mounted on the end caps remain at a constant distance from each other regardless of the temperature thereby canceling out the effect of thermal expansion. The end caps also provide multiple target positioning capability so that any targets mounted thereon may be positioned in various configurations to provide a user with increased versatility for applications such as checking calibration.

Abstract: A metrology instrument, such as a probe, probe head, stylus or stylus arm, for mounting on a coordinate position apparatus. The metrology instrument is at least partially constructed from at least one sheet of thermally stable metallic material which is folded to form a three dimensional structure. The at least one sheet of thermally stable material is utilized in the metrology loop of the metrology instrument.

Abstract: A machine, such as a coordinate measuring machine, having an element and a structure movable with respect to each other along rails, wherein the rails have a different coefficient of thermal expansion than the structure to which they are attached. In one embodiment, a bar is disposed on the structure opposite the rails. This bar has a coefficient of thermal expansion, a stiffness, a spacing from the neutral axis of the structure, and a cross-sectional dimension such that the bar balances any thermal stresses in the structure caused by differential expansion or contraction of the structure and the rails with temperature changes to minimize any bending of the structure. In one embodiment, two rails are disposed on a beam, and a carriage travels on the two rails. For each rail, there is an associated bar disposed on an opposite surface of the beam. In another aspect, a pin extends into an elongated slot on a slide associated with the structure to allow the structure to expand and contact.

Abstract: A machine, such as a coordinate measuring machine, having an element and a structure movable with respect to each other along rails, wherein the rails have a different coefficient of thermal expansion than the structure to which they are attached. In one embodiment, a bar is disposed on the structure opposite the rails. This bar has a coefficient of thermal expansion, a stiffness, a spacing from the neutral axis of the structure, and a cross-sectional dimension such that the bar balances any thermal stresses in the structure caused by differential expansion or contraction of the structure and the rails with temperature changes to minimize any bending of the structure. In one embodiment, two rails are disposed on a beam, and a carriage travels on the two rails. For each rail, there is an associated bar disposed on an opposite surface of the beam. In another aspect, a pin extends into an elongated slot on a slide associated with the structure to allow the structure to expand and contact.

Abstract: A measurement probe (10) is disclosed having strain sensing elements (36) mounted on spokes (38) of a strain sensing member (34). The member (34) is disposed in parallel and spaced from a diaphragm (42). Inner portions of the member and diaphragm are connected to a stylus holder (26) and outer portions of the member and diaphragm are connected to probe body (32). The probe can be used to produce a signal when contact force on the stylus (12) is within an adjustable upper and lower limit, and is thereby suited to use with a manually manipulatable coordinate measuring device.

Abstract: Precision measuring apparatus like Co-ordinate Measuring Machines (CMMs) are very susceptible to deformations due to temperature variations and gradients. In a known CCM such variations are counteracted by providing parts of the apparatus with an insulating PUR layer. According to the invention the metrology frame 2 of the measuring apparatus is provided with a heat shield 12, 15 which includes an inner layer 12, having a comparatively high heat resistance, and an outer layer (14) which has a comparatively low heat resistance. Temperature gradients causing deformations of the metrology frame 2 are thus effectively reduced, whereas homogeneous temperature variations can be easily compensated for by means of software correction. Moreover, the shield acts as a low-pass filter which reduces the temperature disturbances due to short-term heat inputs.

Abstract: Precision measuring apparatus like Co-ordinate Measuring Machines (CMMs) are very susceptible to deformations due to temperature variations and gradients. In a known CCM such variations are counteracted by providing parts of the apparatus with an insulating PUR layer. According to the invention the metrology frame 2 of the measuring apparatus is provided with a heat shield 12, 15 which includes an inner layer 12, having a comparatively high heat resistance, and an outer layer (14) which has a comparatively low heat resistance. Temperature gradients causing deformations of the metrology frame 2 are thus effectively reduced, whereas homogeneous temperature variations can be easily compensated for by means of software correction. Moreover, the shield acts as a low-pass filter which reduces the temperature disturbances due to short-term heat inputs.

Abstract: The ball diameter automatic measurement device according to the present invention preferably comprises a displacement sensor, a dividing plate, a slider and a measurement controller. The displacement sensor measures the diameter of a ball positioned in a measurement position. The dividing plate holds a ball to be measured and reciprocates the same between a predetermined position and the measurement position. The slider rotates the ball in the predetermined position by a predetermined angle when the dividing plate is moved. The measurement controller stores and outputs measured values obtained by repeated measurement and measurement after the rotation of the predetermined angle. According to the device, it is possible to measure a ball diameter accurately without being influenced by body temperature, air temperature and individual workmanship when the diameter of a ball is measured.

Abstract: An inside of a U-shaped frame of a micrometer is made of a material having a smaller linear thermal expansion coefficient than an outside of the U-shaped configuration. Furthermore, a spindle can be made of a material having an extremely small linear thermal expansion coefficient. Accordingly, thermal deformation of the micrometer can be made smaller, and measurement accuracy is maintained even under a widely changing temperature.

Abstract: A handgrip mounting structure in an electric device comprises a main body and a handgrip to be mounted on the main body. The handgrip includes a holding portion, to be held by an operator, having a predetermined length, and mounting portions to be mounted on the main body. The mounting portions are provided at each end of the holding portion. The handgrip has a thermal expansion ratio in the longitudinal direction of the holding portion that is different from that of the main body. At least one of the mounting portions of the holding portion is mounted to the main body so that a shaft member, provided on one of the mounting portions and the main body, is inserted into a through hole formed on the other of the main body and the one of the mounting portions.

Abstract: A measurement device such as a sheet dimension gauge and a method of constructing a gauge which does not require recalibration. The preferred embodiment includes a frame having a transparent top wall with overlaid measurement lines thereon, a measurement guide, a light source, a heater, a thermostat, and a fan. The frame and the transparent top wall are constructed of a material whose dimensions are not susceptible to changes in humidity, but are susceptible to changes in temperature. Therefore, a temperature control system is used during manufacture and operation of the gauge to ensure that the sheet dimension gauge is properly calibrated. A fan, a thermostat, and a heater are mounted within the frame to maintain a uniform temperature inside of the frame slightly above the highest anticipated ambient temperature created by the lights. A one piece measurement guide, which is used to hold the sheet of paper being measured, is rigidly attached to either the frame or the transparent wall.

Abstract: The invention is directed to a coordinate measuring apparatus wherein the influences of temperature on the measuring uncertainty of the apparatus are eliminated. Components of the two pivot arms, which determine the spacing A of the rotational axes (6, 8) and the spacing of the rotational axis 8 to the probe axis 10, are made of materials having positive and negative thermal expansion coefficients.

Abstract: A guideway 10 of a guideway set in a coordinate measuring machine has a scale in the form of a metal strip clamped and bonded to an accessible face 46 of a spar 30, the latter being formed of a thermally stable material and being connected at one end to a reference position defined by a bracket 18 and a mounting plate 16 on the guideway 10. The spar 30 is mounted on the guideway 10 by spaced blocks 34 which are designed to accommodate any longitudinal movement of the guideway 10 due to thermal expansion, so that the spar 30 and the scale are effectively maintained in position. Because relative movement between the spar 30 and the scale is substantially prevented, the position of the scale is substantially fixed, providing improved scale accuracy.

Abstract: A linear encoder for measuring a relative position of two objects and including a scale having a coefficient of thermal expansion between 2.5.times.10.sup.-6 K.sup.-1 and 3.5.times.10.sup.-6 K.sup.-1 approximately, and attachable to one of the objects, and a device for scanning the scale and attachable to the other of the objects.

Abstract: A length measurement device for measuring the relative position of two objects is disclosed wherein a graduation on a scale carrier is scanned by a scanning unit for obtaining measured position values. The scale carrier is connected to a first fixed reference point within the measuring length in a rigid manner, and is connected with a carrier member so as to be longitudinally displaceable, for compensating for measurement errors which are caused by temperature variation. The carrier member is rigidly connected with a first object at a second fixed reference point within the measuring length and is connected so as to be longitudinally displaceable with the first object 1. The first fixed point and/or the second fixed point are changeable or movable within the measuring length.

Abstract: A length measuring system comprises an elongate scale member adapted to be scanned for generating measured-length signals, a tubular scale member carrier defining an internal cavity housing the scale member and including a mounting wall, a connection of the scale member to the scale member carrier, the connection permitting a longitudinal movement of the scale member relative to the scale member carrier, and end blocks rigidly connected to the scale member carrier at both ends thereof, the end blocks defining recesses and having opposite sides.

Abstract: A tubular protective carrier housing for a length measuring system encased in the carrier housing, the housing having a longitudinal axis and comprising two end parts extending from respective sides of a center part, and fastening devices at the center and end parts for affixing the carrier housing to an object, the housing and the object being subject to thermal expansion. To simplify the structure, the carrier housing itself comprises a length equalizing element at the center part for compensating for differences in the thermal expansion of the housing and object.

Abstract: A scale, particularly for a position measuring device, includes a base member and a graduation carrier with a graduation which is fastened with an adhesive layer to the base member. In order to prevent an at least partial separation of the adhesive layer from the contact surface of the base member, the adhesive layer extends in a positively engaging manner with a projection in a dovetail-shaped groove in the contact surface of the base member, so that a secure adhesion of the adhesive layer on the contact surface of the base member is ensured.

Abstract: A structure which has a low coefficient of thermal and moisture expansion along one dimension (an axis) is formed of an arrangement of fibers surrounded by and bonded to an engineering thermoplastic resin. The fibers are arranged so that essentially all of the fibers are disposed parallel to the axis. The fibers have a negative coefficient of expansion, the resin has a positive coefficient of expansion, and the volume ratio is balanced so that the composite structure has a near zero coefficient of expansion. Perferably the structure is formed by pultrusion of overlapped tapes of aligned carbon fibers preimpregnated with polyphenylene sulfide. A scale having this structure has slots for indicating position on the scale. The slots extend through the scale and are transverse to the axis.

Abstract: At least one of the surfaces of the glass or glass-ceramic graduated-scale support (12) of a measuring device is drawn toward a corresponding surface of the guide part (11) by the capillary action of a liquid film (13). The graduated-scale support floats without friction on this liquid film and is secured against floating away laterally by low-friction stops (16-18) which can also be formed of the liquid film itself or suitable shaping of graduated-scale support and of the guide part to which it is mounted. The graduated-scale support advantageously consists of a material having a precisely known small coefficient of thermal expansion, such as quartz glass, or of a material having a negligibly small coefficient of expansion, such as the commercially available glass ceramic material known as Zerodur. By these measures, length or other measurement errors attributable to thermal effects are minimized.

Abstract: A length or angle measuring apparatus which measures the relative position of two objects comprises a scale attached to a first object to be measured and a scanning unit which has at least one scanning element connected to the second object to be measured, wherein the second object and the scanning unit have different thermal expansion coefficients. The graduation of the scale is scanning by a scanning element of the scanning unit at a scanning point. Fastening means are provided which fasten the scanning unit to the second object to be measured, such that the scanning point of the scanning element of the scanning unit has no zero point displacement with temperature changes.

Abstract: Precision measuring machine (10) has a bed (12) with a tailstock (14) and headstock (16) mounted thereon. Anvils (36, 42) are respectively mounted on the tailstock and headstock. Duct walls enclose the lower portion of the bed so that fan (62) can move air therepast. Cap shrouds (72, 82) receive air from fan shrouds (68, 84) to flood air over the tailstock and headstock. Anvil shrouds (76, 90) respectively cover anvils (36, 42) and receive air through tubes (80, 92) to also flood the anvils with air. In this way, the precision measuring machine is bathed in ambient air to reduce dimensional changes due to temperature changes.