Abstract: A gas turbine engine includes a compressor section, a combustion section communicating with and disposed downstream of the compressor section relative to a direction of airflow, and a gas turbine section communicating with and disposed downstream of the combustion section relative to a direction of airflow. One of the sections has a wall defining an opening to access an airflow through the sections. A bleed diffuser assembly is disposed over the opening, and includes a housing including inlet and outlet ends. A diffuser having inlet and outlet ends is movably disposed within the housing. An actuator is coupled to the diffuser for moving the diffuser generally toward the inlet end of the housing and into an operative position when the actuator is energized. A biasing member is provided for urging the diffuser generally toward the outlet end of the housing and into a retracted position when the actuator is de-energized.

Abstract: A passive thermoacoustic cooling apparatus for cooling of components such as miniaturized microelectronics is disclosed. The passive thermoacoustic cooling apparatus includes resonant cavities, a temperature-difference element and a heat conduction element. The temperature-difference element is integrated with the system of resonant cavities for conversion of heat into acoustic power. The heat conducting element connects a heat source to the temperature-difference element, which transmits heat from the source to one end of the temperature-difference component. Due to established temperature gradient across hot and cold ends of the temperature-difference element, acoustic standing wave arises in the resonant cavity system. Forced air convection is thereby generated to cool the heat source.

Abstract: A thermal shield for a superconducting magnet includes a shield body having an annular shape. The shield body includes a material having a thermal conductivity greater than about 1000 W/m·K at about 70K.

Abstract: A cooling system for providing cryogenic cooling fluid to a thermal load, the system comprising: a main cryogenic refrigeration system; a cryogenic cooling fluid feed line having a feed line outlet coupled to the thermal load and a feed line inlet coupled to the cryogenic refrigeration system; a cryogenic cooling fluid return line having a return line inlet coupled to the thermal load and a return line outlet coupled to the cryogenic refrigeration system; a bypass cooling system further comprising isolation valves attached to the feed line and return line wherein each of said valves has a closed position and an open position, a bypass line extending between the feed line and return line, a bypass valve and a cooling device attached to one of said feed line and return line. The bypass cooling system may further include a cold box housing the bypass line and the cooling device, e.g., an open or closed heat exchanger coupled to a storage tank of cryogen.

Abstract: An improved icemaker is provided for a refrigerator. The improvements include tilting the ice mold to assure that the ice cavity nearest the thermostat is filled with water; controlling air flow to the mold to promote rapid freezing of water in the mold cavities; raising the perimeter walls of the mold to minimize water spillage; and providing hooks on the mold for routing electrical wires.

Abstract: A method of fully freezing ice in a refrigerator. The method includes setting a full-frozen temperature for determining whether ice is fully frozen, and a reference ambient temperature for re-adjusting the full-frozen temperature; supplying water to the ice-making tray to thereby perform ice-making; sensing ambient temperature; sensing temperature of the ice-making tray; re-adjusting the full-frozen temperature by comparing the sensed ambient temperature with the reference ambient temperature; and if the temperature of the ice-making tray reaches the re-adjusted full-frozen temperature, driving an ice-transfer motor to transfer full-frozen ice from the ice-making tray. Thus, not fully frozen ice is prevented from being transferred, to thereby improve ice quality and avoid sticking of ice, which may occur when not fully frozen ice is broken while being transferred. A refrigerator using such a method is also disclosed.

Abstract: The present invention provides a heat pump including: a compressor; a radiator; a first throttling device having a variable opening; an expander; a second throttling device having a variable opening; an evaporator; piping that connects the compressor, the radiator, the first throttling device, the expander, the second throttling device, and the evaporator so that refrigerant circulates thorough the elements in that order; and a control device for controlling the opening of the first throttling device and the opening of the second throttling device. This heat pump is capable of independently controlling the pressure of the refrigerant flowing into the expander (intermediate pressure) and pressure in a high-pressure side of a refrigeration cycle, and also is capable of size reduction, or in some cases elimination, of a receiver for the refrigerant.

Abstract: The object of the invention is to provide an ammonia/CO2 refrigeration system in which the ammonia cycle and CO2 brine cycle can be combined without problems even when refrigeration load such as refrigerating showcase, etc. is located at any place in accordance with circumstances of customer's convenience. The system comprises apparatuses working on an ammonia refrigerating cycle, a brine cooler for cooling and condensing CO2 by utilizing the latent heat of vaporization of the ammonia, and a liquid pump provided in a supply line for supplying the cooled and liquefied CO2 to a refrigeration load side cooler, wherein said liquid pump is a variable-discharge pump for allowing CO2 to be circulated forcibly, and the forced circulation flow is determined so that CO2 is recovered from the outlet of the cooler of the refrigeration load side in a liquid or liquid/gas mixed state.

Abstract: A refrigerator includes a refrigerator cabinet, a fresh food compartment disposed within the cabinet, a freezer compartment disposed within the cabinet, an ice compartment disposed within the cabinet, and an electronic control system associated with the refrigerator and adapted to monitor and control the fresh food compartment, the freezer compartment and the ice compartment. The control system provides for energy efficient control and operation through various means, including by monitoring state of an ice maker associated with the ice compartment and controlling temperature within compartments of the refrigerator based on the ice maker state. A damper controls air flow between the fresh food and freezer compartments. The control system can direct heat to the damper if the damper becomes frozen.

Abstract: A substrate processing apparatus includes: a processing room in which a semiconductor substrate may be treated by a process; a cooling unit positioned to cool the processing room, the cooling unit configured to convey cooling fluid; and a temperature-adjusting unit that alters the temperature of the cooling fluid supplied into the cooling unit. The temperature-adjusting unit has a cycling circuit. The cycling circuit has a compressor configured to compress a refrigerant, a condenser configured to condense the compressed refrigerant, an expander configured to expand the condensed refrigerant, the expander including a plurality of expansion valves arranged in parallel, and an evaporator configured to evaporate the expanded refrigerant, the evaporator positioned to cool the cooling fluid.

Abstract: A refrigerator includes a refrigerator cabinet, a fresh food compartment disposed within the cabinet, a freezer compartment disposed within the cabinet, an ice compartment disposed within the cabinet, and an electronic control system associated with the refrigerator and adapted to monitor and control the fresh food compartment, the freezer compartment and the ice compartment. The control system provides for energy efficient control and operation through various means, including adjusting cut-in and cut-out temperatures of the cooling system to control.

Abstract: An air conditioner for a vehicle includes a refrigeration cycle having a variable capacity compressor, a condenser, an expansion valve, and an evaporator; a duct in which the evaporator is arranged; an air switching unit arranged on an upstream side of the duct and configured to switch outside air and inside air from one to the other; an air outlet arranged on a downstream side of the duct and communicating with an interior of the vehicle; and a control unit configured to control a discharge of the compressor. The control unit controls the compressor to provide a maximum capacity if the difference between a vehicle interior temperature and an ambient temperature is higher than a predetermined value and if the air switching unit is switched from a recirculation mode to a fresh air mode.

Abstract: A multi-compressor heat pump system configured to provide heating and cooling over a range of ambient temperatures. The compressors can be operated independently and alone or together in series for maximum output. Heat exchangers are selectively fluidically connected to the compressors to enable refrigerant flow between the compressors and at least two heat exchangers in a manner that enables the heat pump system to be selectively operable in various modes. Preferred aspects include selectively operating the compressors based on the ratio of the evaporating and condensing pressures of the refrigerant within the heat pump system, a mixing chamber between the compressors, and a lubricant management system to prevent the accumulation of a lubricant in one of the compressors.

Abstract: A submersible pumping system includes a submersible pump; a gauge disposed proximate the submersible pump; a Stirling cooler disposed proximate the gauge, wherein the Stirling cooler has a cold end configured to remove heat from the gauge and a hot end configured to dissipate heat; and an energy source configured to power the submersible pumping system.

Abstract: An improved icemaker is provided for a refrigerator. The improvements include tilting the ice mold to assure that the ice cavity nearest the thermostat is filled with water; controlling air flow to the mold to promote rapid freezing of water in the mold cavities; raising the perimeter walls of the mold to minimize water spillage; and providing hooks on the mold for routing electrical wires.

Abstract: An improved icemaker is provided for a refrigerator. The improvements include tilting the ice mold to assure that the ice cavity nearest the thermostat is filled with water; controlling air flow to the mold to promote rapid freezing of water in the mold cavities; raising the perimeter walls of the mold to minimize water spillage; and providing hooks on the mold for routing electrical wires.

Abstract: An improved icemaker is provided for a refrigerator. The improvements include tilting the ice mold to assure that the ice cavity nearest the thermostat is filled with water; controlling air flow to the mold to promote rapid freezing of water in the mold cavities; raising the perimeter walls of the mold to minimize water spillage; and providing hooks on the mold for routing electrical wires.

Abstract: A refrigerator includes a refrigerator cabinet, a fresh food compartment disposed within the cabinet, a freezer compartment disposed within the cabinet, an ice compartment disposed within the cabinet, and an electronic control system associated with the refrigerator and adapted to monitor and control the fresh food compartment, the freezer compartment and the ice compartment. The control system provides for energy efficient control and operation through various means, including by monitoring state of an ice maker associated with the ice compartment and controlling temperature within compartments of the refrigerator based on the ice maker state. A heater is controlled by the control system to increase energy efficiency of the refrigerator.

Abstract: The present invention provides a refrigerator, by which a specific part of a freezer room and/or a specific part of a cold storage room can be adjusted. The present invention includes a body having a cold storage room and a freezer room, an evaporator provided to the body to generate cold air, a plurality of racks partitioning each of the cold storage and freezer rooms into a plurality of chambers, and at least one adjustment unit provided to each rear portion of the racks, the at least one adjustment unit configured to adjust a quantity of the cold air supplied to each of the chambers.

Abstract: A refrigerator comprising a fresh food compartment, a freezer compartment, a lower freezer drawer and an upper freezer bin. A primary set of glides allow the freezer drawer and the upper bin to be pulled out of the freezer compartment. A secondary set of glides mounts the upper bin onto the lower drawer for movement along the drawer, and back into the freezer compartment to allow access to the contents of the lower drawer.

Abstract: Turbulators are disclosed for use in a high-stage generator for an exhaust-fired absorption chiller/heater. The turbulators are designed to minimize pressure drop across the turbulator, and thus minimize the efficiency loss to the exhaust source. One turbulator design has a number of flanges extending at a non-normal angle to a central web. Further, some of the flanges have cutout portions. The overall turbulator design is intended to minimize wake downstream of the turbulator blades, which could otherwise cause undesirable pressure drop. A second turbulator design incorporates flanges that extend at a normal angle relative to the central web, but wherein the flanges have a non-rectangular cross-sectional shape. Again, the goal of the turbulator designs here is to minimize wake, and potential pressure drop.

Abstract: An ejector cycle device includes a compressor that draws and compresses refrigerant, a radiator that radiates heat of high-pressure refrigerant discharged from the compressor, an ejector, a branch passage branched from a refrigerant passage between the radiator and a nozzle portion of the ejector and coupled to a suction port of the ejector, a throttle unit that is arranged in the branch passage and decompresses refrigerant, and an evaporator that is arranged on a downstream side of refrigerant flow of the throttle unit in the branch passage and evaporates refrigerant. Accordingly, even when a suction performance of the ejector is lowered, refrigerant can flow through the evaporator.

Abstract: A fluid compression system includes a compressor that is operable to produce a flow of compressed fluid and a coolant compressor that is operable to produce a flow of coolant. A base includes at least one polymer wall that at least partially defines a reservoir space. The base supports the compressor and the coolant compressor. A first tube is at least partially positioned within the reservoir space and is in fluid communication with the compressor to receive the flow of compressed air and a second tube is at least partially positioned within the reservoir space and is in fluid communication with the coolant compressor to receive the flow of coolant.

Abstract: A multi-compressor heat pump system configured to provide heating and cooling over a range of ambient temperatures. The compressors can be operated independently and alone or together in series for maximum output. Heat exchangers are selectively fluidically connected to the compressors to enable refrigerant flow between the compressors and at least two heat exchangers in a manner that enables the heat pump system to be selectively operable in various modes. Preferred aspects include selectively operating the compressors based on the ratio of the evaporating and condensing pressures of the refrigerant within the heat pump system, a mixing chamber between the compressors, and a lubricant management system to prevent the accumulation of a lubricant in one of the compressors.

Abstract: It is an object of the present invention to provide a refrigerator which is able to improve the efficiency of the refrigerating cycle while avoiding causing the structure of the refrigerator to be complicated, and avoiding a cost increase. Refrigerator 30 includes a refrigerating cycle device 20 having a compressor 1, a radiator 2 connected to a discharge side of the compressor 1, a first expansion valve 31 connected to an exit side of the radiator 2, a gas-liquid separator 33 for separating a refrigerant, which is in a mixed gas-liquid state by being decompressed by the first expansion valve 31, into a gas refrigerant and a liquid refrigerant, a heat absorber 14 into which the liquid refrigerant discharged from the gas-liquid separator 33 flows, and a refrigerant pipe 6D for delivering the gas refrigerant discharged from the gas-liquid separator 33 into the middle pressure portion of the compressor 1; an outer case 40; an inner case 39; and a heat insulating material.

Abstract: A scroll compressor is provided with economizer injection ports, which extend through the wrap of one of the scroll members. Preferably the injection ports are formed through a so-called “hybrid” wrap, which has a varying thickness. The other scroll member is provided with grooves in its base plate. The injection of economizer fluid occurs only during a portion of the orbiting cycle when the injection port and corresponding grooves are aligned with each other. An indentation is formed into the wrap that includes the injection port. The indentation is spaced circumferentially from the injection port. The indentation communicates with the groove, such that refrigerant can pass from the injection port, into the groove, and through the indentation into a compression chamber. This increases the injection time allowing more fluid to be injected into the compression chamber, and provides the scroll compressor designer with greater freedom to achieve desired flow of economizer fluid into the compression chambers.

Abstract: The present invention relates to a refrigerator unit and/or freezer unit comprising a refrigerant circuit, which has a compressor, a condenser, at least one capillary tube as well as at least one evaporator, and a control device for the control of the refrigerant flow through the refrigerant circuit. The invention further relates to a method for the control of such a refrigerator unit and/or freezer unit, wherein at least one operating parameter and/or ambient parameter of the refrigerator unit and/or freezer unit is detected and the refrigerant flow is controlled by the refrigerant circuit in dependence on the detected operating parameter and/or ambient parameter. It is proposed in accordance with the invention to control the refrigerant flow in that the capillary tube is heated by means of a heating device and thereby causing the refrigerant flowing through the capillary tube to evaporate.

Abstract: A method for producing slush nitrogen comprises the steps of: spraying liquid nitrogen from a nozzle into a vessel kept under a reduced pressure with a nozzle diameter and a spraying pressure being so adjusted as for the liquid nitrogen to maintain the form of droplets, to thereby form liquid nitrogen fine particles having a uniform particle diameter and disperse said particles in the vessel; vaporizing nitrogen from the droplet particles during the stay thereof in the space of the vessel, to solidify liquid nitrogen particles by vaporization latent heat and form fine solid nitrogen particles having a uniform particle diameter; and mixing the solid nitrogen particles with liquid nitrogen.

Abstract: A keepsake vessel having an internal memorabilia compartment for the placement, display and storage of a removable locket container therein which contains personal effects and mementos of loved ones. The effects and mementos in the locket can be moved from a concealed storage position in the vessel to a display position exterior of the vessel for viewing by the user, by means of attachment means mounted within the memorabilia compartment, and detachably engageable with and connected to the locket. The locket is accessible by means of a slit or aperture on an exterior of the keepsake vessel, whereby the attachment means connected to the locket can be moved from the concealed storage position to assume a display position exterior of the keepsake vessel for viewing of the locket.

Abstract: Bubbles of uniform diameter of 0.5 to 4 cm of gas such as helium are formed and pass into liquid such as molten glass by accumulating a sufficient volume of gas through a flow restriction into a space upstream of the point of injection at a controlled flow rate.

Abstract: Embodiments of the present invention provide a highly uniform low cost production worthy solution for manufacturing low propagation loss optical waveguides on a substrate. In one embodiment, the present invention provides a method of forming a PSG optical waveguide on an undercladding layer of a substrate that includes forming at least one silicate glass optical core on said undercladding layer using a plasma enhanced chemical vapor deposition process including a silicon source gas, an oxygen source gas, and a phosphorus source gas, wherein the oxygen source gas and silicon source gas have a ratio of oxygen atoms to silicon atoms greater than 20:1.

Abstract: A compact, low profile splicing system for joining optical fibers produces durable, low transmission loss fusion splices. The system employs active optical techniques such as profile alignment or local injection and detection to achieve optimized alignment of the fibers prior to fusion. Light injected into one fiber is propagated across the interface to a second fiber. A detector senses the intensity of the injected light in the second fiber. After the relative position of the fibers is manipulated to maximize the transmitted intensity, the fibers are fusion spliced using an electric arc discharge. The accurate alignment achievable using the local injection and detection system to drive adaptive fiber positioning affords a method for reliably producing low loss splices. The present system is compact and low in profile, making it operable in cramped quarters with limited clearance to adjacent equipment and structures and with only a minimal amount of free fiber slack available.

Abstract: A self-contained machine for removing stains from textiles with the air compressor and solvent all contained with-in the same unit. The machine can be used in a home setting or a coin-changer attached to allow it to be a self-service profit center. This allows stains to be removed quickly and allowing the textile to remain in use without any laundering or drycleaning procedures needed.

Abstract: A travel padlock for securing an article comprises a housing having a shackle, a key lock and a combination lock. An indicator having at least first and second positions is moved from the first position to the second position upon insertion of an object longitudinally into a key hole of the key lock. In at least one embodiment, at least a portion of the indicator extends beyond the exterior of the housing when in the second position. In addition, in at least one embodiment of the present invention the shackle may be rotated to reset the indicator from the second position back to the first position. Furthermore, in at least one embodiment of the present invention the indicator may be reset from the second position back to the first position without rotating the shackle or unlocking the combination lock. Methods of making and using the padlock are also provided.

Abstract: A combination lock and pump having a shackle; a cross-member having a first end and a second end, the cross-member including a hole at the first end and a hole at the second end adapted to receive the shackle; a locking mechanism adapted to engage the shackle at the first end of the cross-member; a pump slidably engaging the cross-member at the second end of the cross-member, the pump having a pump shaft and a pump handle, the pump shaft including a hole to receive the shackle when the combination bicycle lock and pump is in a locked configuration; a connector for engaging an object to be pumped; a first one-way valve allowing air to enter the pump through the first one-way valve when the pump shaft is retracted from the pump and to prevent air from exiting the pump through the first one-way valve when the pump shaft is pushed into the pump; and a second one way valve preventing air from travelling into the pump from the connector but allowing air to be forced into the connector, wherein the shackle engages t

Abstract: A device for protecting a computer peripheral against unauthorized removal includes a signal cord-holding portion having a signal cord holding passage. The signal cord holding portion is transformable between an open condition for receiving the signal cord in the signal cord holding passage or releasing the signal cord and a signal cord holding condition for preventing removal of the signal cord without dismounting from a connector or peripheral. A connecting structure is provided for connecting the device to an object. The signal cord holding portion and the connecting structure are interconnected for securing the signal cord holding portion in the signal cord holding condition if the connecting structure is connected to an object. A device for protecting a computer peripheral against unauthorized removal is also described.

Abstract: A locking device (10) includes a pair of end pieces (12, 14) and a locking member (16). One end piece (12) receives an end of the locking member, while the other end piece (14) is configured to receive the other end when the locking member is inserted through an object to lock the locking device to the object. The end pieces are formed together via a forming process, and are joined together via at least one frangible element or portion (18, 20) that is formed or molded during the forming process. The end pieces thus may be separated via breaking the frangible element or elements when it is desired to lock the locking device to an object. Multiple locking devices may be formed together and may be joined via frangible portions or elements such that a strip or series (22) of locking devices may be unitarily formed together.

Abstract: A mortise lock having a double locking function is provided, which includes: a deadbolt for performing a locking function of a door by going in and out the door; a latchbolt going in and out the door by a handle installed on the door; and a locking member for maintaining the latchbolt in a locked state by keeping the latchbolt projected when the deadbolt is projected, whereby it is possible to improve the security, and reducing breakage and malfunction of the deadbolt due to forced operations of the door, since the door employing the mortise lock cannot be forcedly opened without breaking the latchbolt as well as the deadbolt.

Abstract: A hybrid key for use with a mechanical vehicle entry system and a radio frequency identification (RFID) ignition system. The key can include a mechanical blade that can be received by a vehicle lock, a nose section integrally coupled to the mechanical blade, and a radio frequency transponder housed within the nose section. The nose section and the mechanical blade can be received by an ignition module of the RFID ignition system. The key can include a key head section integrally coupled to the nose section and shaped for an operator to grasp.

Abstract: A protective cover for a keyway disposed on an end surface of a lock is provided. A housing is adapted to be assembled over the lock end surface. The housing includes an opening that surrounds the keyway. At least one door is disposed in the housing opening. The door includes an edge for aligning with the keyway in a key insertion position. When a key is pressed against the door, the door moves away from the keyway, providing a key opening in the housing opening for insertion of the key into the keyway. At least one door biasing member engages the door and biases the edge of the door toward the keyway. The door is mounted on a pivot member disposed in the housing opening such that the pivot member and door pivot within the opening when the key is inserted into the keyway and turned in the lock. At least one pivot biasing member engages the pivot member to hold the edge of the door in alignment with the keyway when the keyway is in the key insertion position.

Abstract: A setup method for preventing a “two-leaf cutting” by only operating the machine without using fingers in cutting the end of a strip blade material 5 having an enclosed rectangular geometry using the apparatus as defined in claim 6, comprising the steps of: the strip blade material 5 being once advanced to a position, as shown in FIG. 13-C, where “two-leaf cutting” will not occur; then the cutting tool 6 being lowered; the cutting tool tip 65 of the cutting tool component 651 being lowered to a level of the same as or under that of the top edge of the strip blade material 5; then the strip blade material 5 being retracted; and finally, the strip blade material 5 being retracted by the same amount as that of the advance from the desired position.

Abstract: An apparatus for producing a battery case which has a tubular shape with a closed end and which houses an electricity-generating element, the apparatus including: a die assembly including a blanking die, a drawing die, a redrawing die and an ironing die which have respective die holes having mutually different sizes and which are immovably and coaxially arranged in series in the order of the sizes of the die holes; a first punch, a second punch and a third punch which are disposed coaxially with respect to the die assembly such that the first through third punches can be inserted into the corresponding die holes of the respective dies; and a moving mechanism which permits the first through third punches to be inserted into the corresponding die holes.

Abstract: The invention relates a drop forging method by means of a forging device provided with a hammer and a forging die, wherein a part placed in the forging die is shaped with a hammer blow, several engravings are formed in the die, a blank is initially inserted into the first engraving and said blank is moved along the other engravings to the last engraving, and then said blank picked up during shaping by a forging gripper. In order to obtain an optimum operating mode, the invention is characterized in that the part is received in a plurality of engravings with each hammer blow. In order to obtain a symmetrical distribution of the hammer load between occupied and non-occupied engravings, the parts are gripped respectively during shaping by the forging grippers.

Abstract: A metal stamping component for a vehicle transmission system which is produced by a novel progressive tool design with enhanced performance and economic characteristics over conventional manufacturing methods.

Abstract: A fast stamping-press end material collector comprises a tray, one or more diverging chutes, and a moving mechanism, arranged such that the work pieces processed by stamping machine slide to the tray through the diverging chutes, and the moving mechanism moves the tray forward or backward when each work piece slides to the tray for the work pieces collected uniformly in the tray.

Abstract: A self-calibrating carbon dioxide sensor that includes a carbon dioxide detector and a carbon dioxide gas generator. In some embodiments, the carbon dioxide gas generator includes a heating element and a carbon dioxide gas releasing solid material in thermal communication with the heating element. The carbon dioxide gas releasing solid material releases carbon dioxide when heated by the heating element. Methods of calibrating a self-calibrating carbon dioxide sensor are also disclosed.

Abstract: A portable, calibratible gas detector includes a multi-position gas inflow limiting orifice. When this orifice is in a calibrating position, a source of calibrating gas can be activated to provide a quantity of gas that diffuses into ambient atmosphere flowing through the orifice. The calibration gas can then be sensed.

Abstract: The present invention relates to the use of internally-generated hydrogen sulfide as a calibration gas for hydrogen sulfide sensors. The present invention also relates to an apparatus and methods for self-calibration of hydrogen sulfide sensors.

Abstract: A method for compensation of the zero error of a Coriolis gyro. The frequency of the read oscillation is modulated. The output signal from a rotation rate control loop or quadrature control loop for the Coriolis gyro is demodulated in synchronism with the modulation of the frequency of the read oscillation to obtain an auxiliary signal. The auxiliary signal is a measure of the zero error.

Abstract: A method of calibrating an articulating probe head comprising the steps of measuring an artefact of known dimensions with the workpiece sensing probe mounted on the articulating probe head, in which the articulating probe head is unlocked. An error functional map is generated corresponding to the difference between the measured and known dimensions of the artefact. Subsequent workpieces are measured with the articulating probe head unlocked and the corresponding correction applied. The true dimensions of the artefact may be determined by measuring it with a probe mounted on an articulating probe head in which the axes of the articulating probe head are locked. A mechanical lock is provided to lock the axes of the articulating probe head.