Hitachi Koki Co., Ltd.

Hitachi, Ltd.

Shun Suzuki

Shigeru Shinohara

Kazuo Tahara

Nobuyuki Yamashita

Masahiro Inaniwa

Masahisa Sobue

Akio Chiba

Shinichi Sakamoto

Satoru Tobita

Toshimi Abukawa

Eiji Nakayama

Junshin Sakamoto

Toshiaki Koizumi

Yoshio Iimura

Yukinori Taneda

Masateru Niyada

Kazuo Kimura

Kumio Takahashi

Tatsuo Innami

Yoichi Ogawa

Shinichi Tsuyuki

Hidetaka Ohsawa

Shin'ichi Sakamoto

Genichiro Kawamichi

Yoshio Hashimoto

Akinori Tsushima

To effectively cool a linear motor used in a shuttle mechanism of a printer and also to increase magnetic flux density used in generating thrust in the linear motor, each magnet used in the linear motor is beveled to form chamfers at corners that confront a coil member and that contact corners of adjacent magnets.

Linear motor driven shuttle mechanism for a printer

An electromagnetic disturbance power (EDP) checker measures disturbance waves of an equipment under test (EUT), that is, a small electric appliance having a power cord. The EDP checker is capable of detecting and measuring disturbance waves even in sites more confined and having more external disturbance waves than in absorbing clamp method. The EDP checker includes a VHF current probe 2, a matching circuit 3 having input impedance matched at a reception frequency of a measuring equipment (receiver) 6 connected to the VHF current probe 2, and a circuit separating mains 4 for designating terminal impedance of the matching circuit 3 and eliminating influence of power source impedance. Power is supplied from the circuit separating mains 4 to drive the EUT 5 connected to the VHF current probe 2. The maximum value of disturbance power generated by the EUT 5 and supplied through the power cord 12 is measured by the measuring equipment 6 connected to the VHF current probe 2.

An EDP checker including a matching circuit

A commutator has a central support supporting a plurality of conductive segments separated by a plurality of insulative segments. In addition to providing an insulative function between the conductive segments, the dielectric constant, the area, and the thickness of the insulative segments are chosen so that they provide a capacitive effect, which capacitive effect suppresses current peaks during operation of the commutator. Preferably, the dielectric constant is greater than 10. The central support may include a metal shaft and an insulating ring, which insulating ring is preferably of material with a lower dielectric constant thereby to suppress-shorting between the shaft and the conductive segments. It is particularly advantageous if the conductive and insulative segments are of ceramics material since this provides good wear resistance. In further alternatives, capacitors are formed between the conductive segments by rings or other bodies of insulative materials of a suitably high dielectric constant.

Commutator

A positioning data correction apparatus with image analyzing, for producing a corrective positioning command used in a positioning device for positioning a tool along an axis with respect to a target on a work in response to a command, comprises: a receiver for receiving the command and a mode signal; a camera connected to the tool for producing an image signal with respect to the axis in response to light from the work; an image analyzer responsive to a control signal and to the image signal for detecting a position of the target by analyzing a pattern along the axis and for producing corrected positioning data by obtaining deviation of the position along the axis from a given point within an angle of field of the camera; and a controller responsive to the mode signal, the received command, and the corrected positioning, the controller operating: sending the received command to the positioning device; and for producing the control signal to case the image analyzer to product the corrected positioning data and producing the corrective positioning command in accordance with the corrected data in the presence of the external control signal.

Positioning data correction apparatus with image analyzing and

Ceramics material are not resistant to tensile force, though they are resistant to compression force. Therefore, ceramics materials, when used as the material of a commutator of an electric rotary machine, tends to be cracked and broken due to tensile stress generated in the inner peripheral portion of the commutator when the latter is press-fitted on the rotor shaft of the machine. The invention is aimed at obviating the above-described problem, so as to make it possible to produce a sliding current collector of an electric rotary machine from a ceramics material. To this end, according to the invention, an annular gap is formed between the inner peripheral surface of the ceramics commutator and the other peripheral surface of the rotary shaft and the gap is filled with a resin such as a thermosetting resin which is then thermally set to form a resin layer by which the commutator is bonded to the rotor shaft. The resin layer effectively absorbs any tensile stress which may otherwise be caused in the inner peripheral portion of the commutator due to, for example, thermal expansion of the rotor shaft. It is thus possible to securely fix the commutator to the rotor shaft without risk of cracking or damaging of the commutator.

Sliding current collector made of ceramics

In a battery charging method and apparatus, a plurality of voltage-division resistors serving as a battery voltage detecting means are connected between the battery and a microcomputer so that a voltage-division ratio can be automatically selected corresponding to the detected battery voltage. Thus, the detected battery voltage applied to the microcomputer is kept substantially constant irrespective of the value of the battery voltage.

Method and apparatus for charging a battery

A tightening apparatus includes a drive motor and a bit are coupled to each other by engagement of a clutch mechanism, the engagement thereof being maintained by a force of a spring one end of which is coupled to the clutch mechanism and the drive motor is released from engagement with the bit when the tightening torque of the bit exceeds a value corresponding to the force of the spring. The tightening apparatus comprises a cylinder and a plunger encased in the cylinder for holding the other end of the spring. The plunger is movable by a drive mechanism such that the force of the spring is varied, whereby the tightening force to be applied to the bit is adjustable in accordance with the position of the plunger as adjusted by the drive mechanism.

Clutch type tightening apparatus for allowing free adjustment of

A drive motor connected to a drill bit serves to actuate the drill bit. An electric current is allowed to flow through the drive motor to activate the drive motor. A mechanism serves to feed the drill bit with respect to a workpiece. The current flowing through the drive motor is sensed. A device stores a value of the current which is sensed when the drill bit is out of engagement with the workpiece. A determination is made as to whether or not a drilling process is completed in accordance with a value of the present sensed current and the stored value of the sensed current.

Drilling machine

A speed controller for a DC motor includes a semiconductor switching device connected in series with it in a DC power circuit. The switching circuit is turned on and off with a duty ratio variable as a function of motor load. A time constant circuit including a capacitor is connected in parallel with the switching device to develop a voltage which is compared with a reference variable between high and low levels in response to the exceedance of the varaible reference. The switching device is turned on when the voltage developed by the capacitor is higher than the lower reference voltage to energize the motor, and is turned off when the capacitor voltage is lower than the higher reference voltage to de-energize the motor. The on-duty period of the motor is variable as a function of a motor-load representative voltage developed in the switching device during its turn-on period and the off-duty period is variable as a function of a counter-electromotive force generated in the motor as inversely proportional to motor load.

Variable duty ratio speed controller for DC motors

A circuit arrangement including a computer is built in an electrical jig saw where various data or information, such as the sort of the material of the workpiece, the thickness of the workpiece, desired degree of finish and way of cutting, are manually inputted via a keyboard so that the computer selects and determines optimum working condition, such as the sort of blade to be used, the locus of the blade, blade strokes per minute which is in proportion to the motor speed, and the necessity of application of coolant oil. The circuit arrangement also comprises circuitry for automatically controlling the rotational speed of the motor of the jig saw so that an actual speed of the blade equals a desired speed represented by strokes per minute. A display unit is coupled with the computer for indicating input and output data of the computer for supplying visual information to the user of the jig saw.

Computerized circuit arrangement for jig saw

A quick battery charger according to the present invention comprises a circuit for detecting the voltage of the battery (3), a constant-current charging circuit, a constant-voltage charging circuit, and a timer circuit responsive to the voltage detecting circuit. At the beginning in charging operation, the battery is charged at a constant current, and when the voltage of the battery exceeds a predetermined value, charging mode is changed to constant-voltage charging which last for a predetermined period of time determined by the timer circuit. The charger may also comprise a trickle charge circuit so that trickle charge takes place after the constant-voltage charge. One or more heat-sensitive elements (5, 6, 69) may be used for providing temperature compensation or fail-safe in response to the heat from the battery and heat from parts of the battery charger. As a timer may be used a capacitor (50) which may be forcibly charged to insure a given period of time of the constant-voltage charging. A differential amplifier (42) may be used for detecting the voltage of the battery so that a power transistor (13) used as an element of the constant-current charging circuit is controlled in response to an output signal from the differential amplifier (42) to perform constant-voltage charging.

Circuit arrangement for rapidly charging a battery

An electric wire is wound as coil turns in slots in electric rotating machinery component such as a stator or an armature. The wire as it is supplied from a nozzle or flyer is guided by movable formers into successive layers of coil turns in the slots without forming an unwanted dead space in the slots. The formers are moved in radial increments to provide successive spaces in the slots for allowing the successive coil turn layers to be neatly laid in the spaces.

Growing community of inventors

Katsuta, Japan

Shun Suzuki