Abstract: An absolute linear encoder includes a plurality of absolute scales aligned in the detection direction with absolute calibrations, a plurality of detectors for detecting the calibrations on the absolute scales, absolute position data generating portions of each scale for generating absolute position data of each detector, and a calculator for outputting an absolute position over the whole length of connected whole absolute scales adding the absolute position data of each detector and the distance between the detectors. The detectors are fixed at such intervals as to simultaneously detect the calibrations of the two absolute scales adjoining in a scale connecting section. Thus, the long absolute linear encoder which is easy to use is realized at low costs.

Abstract: A linear scale attachment device for holding and securely attaching a linear scale on an object to be measured is disclosed. The device includes an aluminum base formed with a holding groove having a larger opening than the width of a linear scale that is fitted in this groove, and a retainer for preventing the linear scale fitted in the holding groove from falling off. The base is permanently attached to the object at one location in the lengthwise direction, and resiliently attached at one or more other locations such as to be pressed in the X and Y directions using a cantilever plate spring. While using an aluminum base, the attachment device allows easy attachment and maintenance of the scale and relieves the effect of thermal stress caused by a difference in the thermal expansion coefficient between the aluminum base and the object.

Abstract: An absolute linear encoder includes a plurality of absolute scales aligned in the detection direction with absolute calibrations, a plurality of detectors for detecting the calibrations on the absolute scales, absolute position data generating portions of each scale for generating absolute position data of each detector, and a calculator for outputting an absolute position over the whole length of connected whole absolute scales adding the absolute position data of each detector and the distance between the detectors. The detectors are fixed at such intervals as to simultaneously detect the calibrations of the two absolute scales adjoining in a scale connecting section. Thus, the long absolute linear encoder which is easy to use is realized at low costs.

Abstract: A linear scale attachment device for holding and securely attaching a linear scale on an object to be measured is disclosed. The device includes an aluminum base formed with a holding groove having a larger opening than the width of a linear scale that is fitted in this groove, and a retainer for preventing the linear scale fitted in the holding groove from falling off. The base is permanently attached to the object at one location in the lengthwise direction, and resiliently attached at one or more other locations such as to be pressed in the X and Y directions using a cantilever plate spring. While using an aluminum base, the attachment device allows easy attachment and maintenance of the scale and relieves the effect of thermal stress caused by a difference in the thermal expansion coefficient between the aluminum base and the object.

Abstract: An optical encoder comprises a main scale (1) having scale gratings (11) formed thereon with a certain angular pitch along a measurement axis (x1) that describes a circular arc. It also comprises a detection bead (2) having photoreceptive optical gratings (7) formed thereon. The detection head is arranged relatively movable along the measurement axis (x1), opposing to the main scale (1). The photoreceptive optical gratings (7) on the detection head (2) have transparent and opaque portions alternately arranged with a certain distance pitch along a straight, grating arrangement axis (x2).

Abstract: There is disclosed a supercharger for an engine in which intake air is increased in pressure by the use of exhaust gas flowed into the supercharger from the engine, and is fed to the engine. An impeller 2, having a plurality of blades formed on an outer peripheral portion thereof, is received within a casing 1, and a ring-like fluid passage is formed around the plurality of blades, and a first partition 3 and a second partition 4 are provided in the fluid passage to divide this fluid passage into two fluid passages, that is, an exhaust gas passage 6 and an intake air passage 9. There is provided a fluid machine construction for causing the exhaust gas of the engine to flow into and out of the exhaust gas passage, and for causing the intake air to flow into and out of the intake air passage.

Abstract: A turbo vacuum pump has a rotor and magnetic bearings. The magnetic bearings are held in a housing having a suction port and an exhaust port, and support the rotor rotatably. A peripheral flow pump stage and screw pump stage are formed in the rotor, so that the pressure at the exhaust port can be at or near atmospheric pressure level. Before starting the turbo vacuum pump, the magnetic bearings are operated to displace a rotor position and to scrape off the reaction products which have deposited inside the pump. In addition, before starting the turbo vacuum pump, a stator of the pump is heated up to decrease a binding force of the reaction products. Therefore, the pump can be restarted, even if the rotor has locked by the solidification of deposited reaction products formed during stopping of the pump.

Abstract: A turbo vacuum pump for compressing a low-pressure gas to discharge the compressed gas into atmosphere comprises pump stator having a gas flow passage comprising a plurality of annular flow passages on an inner surface thereof arranged stepwise diameters of which become smaller toward downstream and passages intercommunicating with adjacent annular flow passages and a gas discharge port communicated with one of the plurality of annular flow passages disposed at the most downstream. The pump stator includes a cylindrical spiral grooved pump impeller and a plurality of peripheral flow pump impellers facing the annular flow passages provided downstream of the cylindrical spiral grooved pump impeller and having stepwise diameters which become smaller toward downstream to form a peripheral flow pump stage.

Abstract: A turbo vacuum pump has a housing provided with a suction port and a discharge port, an evacuation pump disposed in the housing for compressing a gas suctioned through the suction port and discharging the compressed gas through the discharge port, and a motor for driving the evacuation pump, the motor and the evacuation pump having a common rotor. The rotor is supported at its both axial ends by bearings. A spiral grooved dynamic seal is disposed in the vicinity of the suction port and at the opposite side of the suction port to the evacuation pump. The diameter of the spiral grooved dynamic seal, at the smallest, is greater than the outside diameter of the final stage impeller of the evacuation pumps.

Abstract: A compact, easy-to-handle turbo vacuum pump includes a housing having an inlet port and an outlet port; a cylindrical rotor disposed in the housing and having a stepped peripheral surface and a plurality of blades secured to protruding corners of the steps; and a pumping mechanism portion in which a pumping stage is formed by a stator which faces the blades of the rotor across a narrow gap, and in which peripheral pump flow paths are provided in step-like recessions inside the stator. The turbo vacuum pump further includes a rotating shaft which is connected to the rotor and is rotatably supported by a radial gas bearing and a thrust gas bearing; and a motor portion for operating the rotor. Gas sucked in through the inlet port can be discharged into the atmosphere through the outlet port.

Abstract: A turbo vacuum pump has a housing provided with a suction port and a discharge port, an evacuation pump disposed in the housing for compressing a gas sucked through the suction port and discharging the compressed gas through the discharge port, and a motor for driving the evacuation pump, the motor and the evacuation pump having a common rotor. The rotor is supported at its both axial ends by bearings. A spiral grooved dynamic seal is disposed in the vicinity of the suction port and at the opposite side of the suction port to the evacuation pump. The diameter of the spiral grooved dynamic seal, at the smallest, is greater than the outside diameter of the final stage impeller of the evacuation pump.

Abstract: Since a peripheral-flow pump according to the present invention has a peripheral-flow impeller having a cylindrical staircase shape whose outer diameter increases in one direction only like a staircase, a stator, which conventionally has been of a complicated configuration composed of two pieces, can be formed into an integral molding without any deterioration in pump performance. Accordingly, the production of pumps is facilitated.

Abstract: In an optical encoder using a collimated lighting system, an index scale is inclined toward a main scale by a predetermined value. With this arrangement, a component of variation in the detection signal due to variations in the grating gap can be offset or integrated to be removed from a geometric image of the first grating in the detection signal, whereby the dependence of an S/N ratio of the detection signal on the grating gap can be avoided.

Abstract: In a reflection type encoder having a main scale and an index scale with first and second gratings, respectively, and using a diffusing light source, diffused rays from a point light source are focused by a condensing lens to produce a secondary point light source positioned on a plane defined by the second gratings of the index scale. With this arrangement, a collimator lens can be dispensed with, so that the encoder can be rendered compact in size. Furthermore, the respective elements can be easily supported and positioned.

Abstract: In a diffraction type optical displacement encoder using a diffractive light source and having a main scale grating and an index scale grating, a light-receiving element receives two rays satisfying a relationship concerning the lengths of light paths at the rays between the light source and the index scale grating, and the width of the light receiving element, wherein the difference between the path length of each ray is approximately equal to an integral multiple of the square of the pitch of the main scale grating divided by the wavelength of the light source, and the width of the light receiving element, measured as the distance between the impingement points of the two rays at the index scale, is integrally related to the difference in ray path lengths and the angle of the impinging rays due to an offsetting of the light-receiving element.

Abstract: In a linear scale type displacement measuring instrument including: a case fixed to one of relatively movable members; a main scale; a carriage; index scales and a detector; the carriage and the other of the relatively movable members are connected to each other through a connecting mechanism, one end of which is connected to the carriage, the other end of which is connected to the other of the relatively movable members in a location where a section standard length of the main scale is maintained as it is when the main scale is straight, i.e. within the neutral planes of the case as a whole including the main scale mounted, and capable of permitting the carriage to change the posture thereof such that the index scales can be held in a state of perpendicularly intersecting the normal line of the surface of a warp of the main scale.

Abstract: In a seal device in a displacement measuring instrument, comprising a hollow case fixed to one member, a connecting rod for imparting a displacement of the other member to a displacement detecting mechanism housed in the hollow case through the opening and seal members disposed at opposite sides of the opening, for shielding a penetrating portion of said connecting rod, to enhance the drip-proof performance, a difference is given between the positions of the forward ends of lip members constituting said seal members, whereby the forward end of the lip member disposed at one side where liquid drops are generated is projected farther than the forward end of the lip member disposed at the other side, and/or a liquid receiving groove extending along the opening is provided at least at one side of the inner surface of the hollow case, liquid drain holes are formed in the bottoms of the liquid receiving grooves, filters for excluding dust intruding from outside are provided in the liquid drain holes, and/or liquid

Abstract: A measuring instrument for measuring the contour of the outer surface of a workpiece. This measuring instrument is of such an arrangement that the tip end of a stylus solidly secured at one end of an arm adapted for rotational movement is brought into contact with the outer surface of the workpiece by a slight pressing force, the arm in this condition is moved in the axial direction thereof, and the displacement of the stylus tracing the irregularities of the outer surface of the workpiece to vertically move due to the abovedescribed movement is converted into the rotational movement of the arm, which is measured by measuring means such as a differential transformer, whereby the contour of the outer surface of the workpiece is measured from the vertical movement of the stylus and the axial (or horizontal) movement of the arm.

Abstract: A dust excluding device for a linear scale type measuring instrument which comprises; flexible shield members disposed at opposite sides of an opening formed in a hollow casing along a line of movement of a movable member and having the forward ends thereof being brought into abutting contact with each other; and a neck adapted to locally push open the abutting contact portions of the shield members, for imparting a displacement of the movable member at the outside of said hollow casing to the interior of said hollow casing through said opening; characterized in that the end portions of said neck in the moving directions thereof are each formed into a letter `V` shape, the tip of which obliquely recedes from inside to outside of said hollow casing.