Abstract: An electrostatic motor has a container having a main body, a stator fixed to the main body in the container; and a rotor which is disposed opposite to the stator in the container, and which is pivotally supported so as to freely rotate via a rotating shaft. The stator has first electrodes attached to a first electrode support and second electrodes attached to a second electrode support. The first electrodes and the second electrodes are electrically insulated. The rotor has third electrodes attached to a third electrode support and fourth electrodes attached to a fourth electrode support. The third electrodes and the fourth electrodes are electrically insulated, and the third electrodes and the fourth electrodes are respectively arranged at different positions from the first electrodes and the second electrodes in a radial direction of the rotor so as to be spaced apart from the first electrodes and the second electrodes.

Abstract: An electrostatic motor has a disc-shaped stator and a disc-shaped rotor are opposed to each other in a vacuum container. In the stator, first electrodes and second electrodes, which are attached to electrode supports, and which are electrically insulated from each other by an insulator, are arranged alternately in the circumferential direction. In the rotor, first electrodes and second electrodes, which are attached to electrode supports, and which are electrically insulated from each other by an insulator, are arranged alternately in the circumferential direction. The first electrodes and the second electrodes on the side of the stator are arranged at a spacing of two or more rows at a predetermined distance from the center of a rotating shaft.

Abstract: Molten resin is injected into a cavity 12 formed between a cavity mold 7 and a moving-side core mold 11 in an injection mold assembly 1 and is allowed to spread out into every corner. Next, after the resin has stopped flowing, punch pins 23 and 24 are pressed into the cavity by hydraulic cylinders 25 and 26 that are attached to the fixed-side mold part 2 side. After the molten resin has hardened, the punch pins 23 and 24 are withdrawn from the cavity, the mold assembly is opened and the molded product is removed. By using the punch pins 23 and 24, through-hole parts are formed in a plate-like product. When the molten resin is injected, inside the cavity there are no through-hole-forming protrusions that would cause the flow of the molten resin to branch, so that weld lines do not appear in the surface of the molded product. As a result, plate-like molded products that include through-holes can be accurately formed by injection molding.

Abstract: In a piezoelectric vibrator used for acoustic equipment, a vibration control piece composed of an elastomer is attached to the peripheral section of the piezoelectric plate of the vibrator. The shape of the vibration control plate is decided so that the distance between an axial line which is perpendicular to the straight line connecting the center of the piezoelectric plate to the center of gravity of the vibration control piece and passing through the center of the plate and the center-of-mass line of the vibration control plate can change along the axial line, or the masses of the cut pieces of the vibration control plate cut along a plurality of straight lines parallel to the straight line connecting to the center of the piezoelectric plate to the center of gravity of the vibration control piece can change along the axial line which is perpendicular to the straight line and passes through the center of the piezoelectric plate.

Abstract: A driving device (14) of an acoustic vibration plate (11) is arranged between a speaker frame (10) and the acoustic vibration plate (11). The driving device (14) is comprised of a pair of piezoelectric vibration plates (1, 2) arranged facing each other across a certain distance. The outer peripheries of the piezoelectric vibration plates (1, 2) are connected to each other by an annular spacer (7). When a drive signal is applied to the piezoelectric vibration plates (1, 2), the piezoelectric vibration plates (1, 2) repeatedly undergo flexing motion wherein their centers flex alternately in opposite directions. At this time, the flexing directions of the piezoelectric vibration plates (1, 2) are always reverse to each other.

Abstract: A cassette mold holder (7) has a cassette mold insertion portion (12) into which a cassette mold (14) is inserted from above. The insertion portion (12) is inclined with respect to a vertical line (VL) by about 6.degree. when the holder (7) is attached to an injection molding machine. An insertion port (121) of the insertion portion (12) is large, and the inside surfaces (12b, 12c) adjacent to the insertion port have tapered surfaces (12d, 12e) respectively to guide the cassette mold into the insertion hollow portion. Since the insertion portion (12) is inclined, when the cassette mold (14) is inserted, one of the inside surfaces (12b) and the bottom (122) function as reference surfaces to position the cassette mold automatically. Further, the cassette mold (14) can be inserted easily along the tapered surfaces (12d, 12e).

Abstract: A small-sized ultrasonic motor can produce a high torque and a stable turning force. The ultrasonic motor has: a cylindrical casing, a hollow output shaft extending coaxially through the cylindrical casing supported rotatably by the casing a ring-like stator fixedly mounted on the inner surface of the cylindrical casing having piezoelectric elements fixed on the back surface thereof, a ring-like rotor mounted on the hollow output shaft and facing the front surface of the stator, and springs for pushing the rotor toward the stator. Also disclosed is a laser beam welding apparatus for welding the inner circumferential surface of a tube by using the ultrasonic motor.