Abstract: In a magnetic tape drive for a single-reel type magnetic tape cartridge having a leader block coupled to a leading end of a magnetic tape wound therein, a hub for winding the tape pulled out of the cartridge is disposed at rear side of a magnetic head unit for writing data on and reading data from the tape, and has a radial slot formed therein for receiving the leader block of the tape threaded through the unit. The rotational direction of the hub is determined such that the leader block is subjected to an radially-inward force in the slot of the hub at the beginning of a rotational movement of the hub, whereby slippage of the leader block from the slot of the hub can be prevented.

Abstract: Disclosed herein is a magnetic tape unit having a magnetic head for reading and writing data from and onto a magnetic tape. The magnetic tape is traveled in contact with the magnetic head during a read/write operation of the magnetic head. During a rest period where the read/write operation of the magnetic head is not performed, a reciprocating motion of the magnetic tape by a small distance is performed with a predetermined period. A temperature in the vicinity of the magnetic head is detected by a temperature sensor. The predetermined period is changed according to the temperature detected by the temperature sensor. Accordingly, the adhesion of the magnetic tape to the magnetic head can be well prevented irrespective of the temperature inside the tape unit.

Abstract: An improvement in conditions that protective functions of an insulated gate semiconductor device with a protection circuit incorporated therein are performed, an improvement in the cutoff of heating, the prevention of malfunctions and an improvement in ease of usage can be achieved.The insulated gate semiconductor device of the present invention comprises a power insulated gate semiconductor element (M9), at least one MOSFET (M1 through M7) for a protection circuit, for controlling the power insulated gate semiconductor element, a constant-voltage circuit using forward voltages developed across diodes (D2a through D2f) for the constant-voltage circuit, and voltage restricting diodes (D1 and D0a through D0d) for controlling the upper limit of a power supply voltage of the constant-voltage circuit. Power to be supplied to the voltage restricting diodes is supplied from an external gate terminal of the power insulated gate semiconductor element.

Abstract: A magnetic tape drive for driving a magnetic tape stored in a cartridge for writing and reading data as an external storage device of a computer, etc., and equipped with a leader block at a distal end thereof, comprises a file reel having the cartridge fitted thereto, and a machine reel rotating in the same direction as the file reel while the leader block is fitted to a hub thereof, and taking up the magnetic tape, wherein data is written/read to and from the magnetic tape in a travelling path between the file reel and the machine reel. In this construction, the magnetic tape is wound at an initial tension lower than a normal tape tension at the start of winding of the magnetic tape by the machine reel until a predetermined number of turns of the magnetic tape is wound on the machine reel, and thereafter the tape is wound at a greater tension.

Abstract: Source and drain electrode metals of a field effect transistor having a recessed gate electrode metal are directly connected to a high impurity concentration semiconductor layer which faces the gate electrode metal through an insulator film which defines the side wall of the recess. The source and drain electrode metals may be disposed so as to face the gate electrode metal through the side insulator film. With this arrangement, it is possible to lower the parasitic resistance between the gate electrode and another electrode of the field effect transistor, to lower the contact resistance between a semiconductor layer and the source and drain electrodes, to reduce the capacitance of the recess gate electrode and to increase the source-gate breakdown voltage, advantageously. The above-described arrangement is particularly suitable for a transistor employing a compound semiconductor, and can also be applied to semiconductor devices other than field effect transistors.

Abstract: Source and drain electrode metals of a field effect transistor having a recessed gate electrode metal are directly connected to a high impurity concentration semiconductor layer which faces the gate electrode metal through an insulator film which defines the side wall of the recess. The source and drain electrode metals may be disposed so as to face the gate electrode metal through the side insulator film. With this arrangement, it is possible to lower the parasitic resistance between the gate electrode and another electrode of the field effect transistor, to lower the contact resistance between a semiconductor layer and the source and drain electrodes, to reduce the capacitance of the recess gate electrode and to increase the source-gate breakdown voltage, advantageously. The above-described arrangement is particularly suitable for a transistor employing a compound semiconductor, and can also be applied to semiconductor devices other than field effect transistors.

Abstract: Disclosed is a semiconductor device including a heterojunction bipolar transistor in which the front surface of a base layer and the surface of an emitter-base junction are covered with a high-resistivity layer of compound semiconductor containing at least one constituent element common to an emitter layer and the base layer.

Abstract: A pair of cut-off ports are formed in a plunger and a plunger barrel at a predetermined axial location and registrable with each other to spill pressurized fuel into a zone under lower pressure. A communication passageway communicates a pump working chamber defined by the plunger at one end thereof with the zone under lower pressure. A solenoid valve is arranged across the communication passageway for blocking same. Control means controls the solenoid valve to cause same to selectively assume an open position and a closed position. While the plunger moves toward the pump working chamber, the solenoid valve is closed by the control means to start injection of fuel present in the pump working chamber, and upon registration of the cut-off ports with each other, the fuel injection is terminated.

Abstract: A control signal which corresponds to an actual operating condition of the engine is determined on the basis of the design specifications irrespective of an actual operation amount of an operating member of the fuel injection apparatus. The result of the determination is provided for controlling a coupled apparatus which is equipped with the engine.

Abstract: This invention consists in improvements in a buried-heterostructure laser with buried optical guide, and facilitates the oscillation of the laser in the fundamental mode thereof and also enhances the available percentage of production of the laser. An active layer and an optical guide layer are sandwiched between two cladding layers, to form an optical confinement region. The width of the semiconductor material assembly varies in the direction of the stacked layers, and the narrowest part thereof is located on a side opposite to the optical guide layer with reference to the position of the active layer. The side surface of said semiconductor material assembly parallel to the traveling direction of laser radiation is buried by a burying layer.

Abstract: A distribution type fuel injection pump for use in a fuel injection combustion engine comprising a plunger capable of moving reciprocally along its axis and simultaneously rotating about its axis and a couple of members forming a cam mechanism having a first cam member and a second cam member. The first cam member is mounted on the plunger and the second cam member is mounted on a housing rotatably about its axis. The couple of cam members cause the plunger to reciprocally move while the plunger is rotating. The angular position of the second cam member about its axis can be controlled by a fuel injection timing control means in accordance with the engine speed. The second cam member can also turn about its axis so as to be adjusted in its angular position by a fuel injection timing adjustment when a selected operating condition of the engine, for example the engine start, is carried out.

Abstract: A distribution type fuel injection apparatus has a fuel injection pump having a solenoid valve for controlling pressure of a high-pressure chamber of the apparatus. The solenoid valve is actuated or deactuated at the optimum time for fuel injection end or beginning by a control signal produced by a circuit for computing the optimum timing in accordance with the condition of engine operation. Thus, precise control of injection timing or injection amount injected can be attained by electronic control without a complex mechanical structure.

Abstract: In a fuel injection apparatus comprising an actuator for driving a member for controlling the amount of fuel injected, a computing circuit for computing a first signal representing an optimum amount of fuel injected on the basis of the engine operation conditions and a signal generator for generating a second signal representing the amount of fuel injected from an injection nozzle, the signal generator has a detector for generating a position signal indicative of the position of needle valve of the injection nozzle at the instant of injection, a converting circuit for converting the position signal into an open area signal representing an open area of the injection nozzle and a computing circuit for computing a signal indicative of the actual amount of fuel injected on the basis of the open area signal.

Abstract: A distribution type fuel injection pump for use in a fuel injection combustion engine comprising a plunger capable of moving reciprocally along its axis and simultaneously rotating about its axis and a couple of members forming a cam mechanism having a first cam member and a second cam member. The first cam member is mounted on the plunger and the second cam member is mounted on a housing rotatably about its axis. The couple of cam members cause the plunger to reciprocally move while the plunger is rotating. The angular position of the second cam member about its axis can be controlled by a fuel injection timing control means in accordance with the engine speed. The second cam member can also turn about its axis so as to be adjusted in its angular position by a fuel injection timing adjustment when a selected operating condition of the engine, for example the engine start, is carried out.

Abstract: In a distribution type fuel injection system, the fuel injection advance angle, or the relative angular position at which fuel injection begins, is controlled by a first spring loaded piston (44). The spring force is opposed by pressurized fuel from a pump (14), the pressure increasing with engine speed. A second spring loaded piston (49) moves the first piston (44) to an advanced position for starting the engine and is retracted when the fuel pressure reaches a certain value to subsequently retard the advance angle in an idling speed range. The fuel pressure moves the first piston (44) to progressively advance the angle in a higher speed range. An electromagnetic valve (62) is controlled to trap fuel and apply a hydraulic lock to the second piston (49) during starting of the engine to prevent retarding of the advance angle until the engine speed or coolant temperature reaches a predetermined value.

Abstract: In a distributor type fuel injection pump including a load-responsive pressure adjusting device which is responsive to engine loads for allowing drainage of part of the fuel in the suction chamber of the pump into a zone under lower pressure in the pump when the engine is operated within a predetermined load range, a pressure setting valve is provided in a drainage passage forming part of the pressure adjusting device, which is adapted to open at a predetermined pressure. The pressure setting valve enables establishment of necessary fuel pressure for normal actuation of a fuel injection timing control device provided in the pump within a low engine speed (rpm) range even during operation of the pressure adjusting device.

Abstract: A start lever (56) and a tension lever (18) are rotatable about a pin (19). The tension lever (18) is connected to a fuel control sleeve (28) so that an amount of fuel pumped and injected into an engine depends on the position of the tension lever (18) and sleeve (28). Upon rotation of flyweights (13), a governor rod (52) is urged through a hole (54) in the start lever (52) toward the tension lever (18) against the force of a start spring (22). A flange (53) formed on the governor rod (52) abuts against the start lever (18) so that the force of the start spring (22) is transmitted to the flyweights (13). The end of governor rod (52) abuts against the tension lever (18) at a certain engine speed so that further movement of the governor rod (52) is opposed by a governor spring (26) connected to the tension lever (18).

Abstract: A fuel injection pump in which a relief channel is formed which communicates with the pump working chamber and is arranged to be blocked by a valve means, associated with a valve actuating means responsive to a pressure varying with engine r.p.m., during starting of the engine so that the fuel injection quantity is increased. Thus, improved starting characteristics of the engine can be obtained. Said relief channel may comprise a first channel communicating with the pump working chamber, and a second relief channel which has a portion thereof extending in the pump plunger to terminate in an outer periphery of the bottom end of said plunger and is so disposed as to communicate with the pump suction chamber after a predetermined delivery stroke length or prestroke has been executed. Communication between said first and second relief channels is adapted to be interrupted by said valve means at less than a predetermined engine r.p.m.

Abstract: In a distribution type fuel injection system, the injection advance angle, or the relative angular position at which fuel injection begins, is controlled by a first spring loaded piston (44). The spring force is opposed by pressurized fuel from a pump (14), the pressure increasing with engine speed. A second spring loaded piston (49) moves the first piston (44) to an advanced position for starting the engine and is retracted when the fuel pressure reaches a certain value to retard the advance angle in an idling speed range. The fuel pressure moves the first piston (44) to progressively advance the angle in a higher speed range. An O-ring (61) is provided to an end of the second piston (49) which abuts against an end wall (53) so that the fluid pressure receiving area of the second piston (49) is small when the second piston (49) abuts against the end wall (53) but is greater when the second piston (49) is moved away from the end wall (53).

Abstract: A fuel injection pump in which a relief channel is formed which communicates with the pump working chamber and is arranged to be blocked by a valve means, associated with a valve actuating means responsive to a pressure varying with engine r.p.m., during starting of the engine so that the fuel injection quantity is increased. Thus, improved starting characteristics of the engine can be obtained. Said relief channel may comprise a first channel communicating with the pump working chamber, and a second relief channel which has a portion thereof extending in the pump plunger to terminate in an outer periphery of the bottom end of said plunger and is so disposed as to communicate with the pump suction chamber after a predetermined delivery stroke length or prestroke has been executed. Communication between said first and second relief channels is adapted to be interrupted by said valve means at less than a predetermined engine r.p.m.