Abstract:
A printer which is compact, can accurately supply paper and has reduced noise characteristics. Additionally, the printer enables easy correction of paper jams and can be selectively operated in various modes according to the user's preference. The printer includes a paper feed roller which is pivotable between a paper feed position and a non-feeding position, a drive force transmitting mechanism for transmitting a drive force to the paper feed roller, a carriage reciprocatively movable along the width of the paper fed by the paper feed roller, and an intermediate transmission mechanism attached to the side of the carriage. Only when the carriage is in a stand-by position, the intermediate transmission mechanism couples with the drive force transmitting mechanism to transmit to the paper feed roller a paper-feed directional rotating force so as to rotate the paper feed roller to the paper feed position. The intermediate transmission mechanism is preferably an idler rotatably mounted on the side of the carriage. The paper feed roller is preferably driven through a planetary gear mechanism including a sun gear provided on a drive shaft, a paper-feed roller holder rotatably mounted on the drive shaft, and a planetary gear coaxially provided with the paper feed roller supported with the paper-feed roller holder.
Abstract:
An operator compartment protecting device (12) for construction vehicles is located to the rear and above an operator compartment (11) on a vehicle body (10) in order to protect the operator compartment (11). The operator compartment protecting device (12) includes: a gate-shaped support (15) including a pair of vertical members (13), and a connecting horizontal member (14) extending between and fixed by welding to a side surface of an upper end portion of one of the pair of vertical members (13) and a side surface of an upper end portion of the other of said pair of vertical members (13); a pair of beam members (16) each fixed by welding to the front surface of the upper end portion of each of the pair of vertical members (13) in such a manner that they are directed in a forward direction, and a ceiling plate (17) placed over and releasably secured, e.g., by bolts, to an upper surface of each of the pair of beam members (16), an upper surface of each of the pair of vertical members (13), and an upper surface of the connecting horizontal member. It is possible to lift the operator compartment (11) through the opening between the beam members (16) by merely releasing the engagement of the bolts (18).
Abstract:
A circuit for an encoder apparatus of an incremental-type construction, including: a unit mechanically joined to a movable machine; a unit for outputting at least two signals having a phase shift and a periodic waveform in response to movement of the unit; a battery-type power supply; and an electric ciruit including a circuit for generating a timing pulse having predetermined frequency and pulse width, a circuit for detecting a change of the signals from the signal outputting circuit and for outputting a pulse signal in response to the change of signals, and a circuit for counting the pulse signal from the signal-change detecting circuit. The apparatus may be optical or magnetic in construction.
Abstract:
Electric current supply circuits (23), (24) each having a switching element are inserted at an electric power supply side (31) and at an electric power return side (32) of a differential amplification means (10) in a voltage comparison device, and the electric current supply circuits having the switching element are controlled to turn ON/OFF. Thus, a voltage comparison device with a low electric power consumption and a high speed intermittent operation can be achieved.
Abstract:
Disclosed is an induction motor drive apparatus which produces three-phase current commands using a speed error (ER) between a speed command and an actual speed (n) for driving an induction motor (10) on the basis of the current commands. The induction motor drive apparatus receives the speed error (ER) and the actual speed (n) as input signals and generates, through digital processing, a first phase sinusoidal signal and a second phase sinusoidal signal shifted by 2.pi./3 from the first phase sinusoidal signal. The first and second sinusoidal signals are used for generating a phase current (i.sub.w) in a first and second phase currents (i.sub.u, i.sub.v) which are in turn used to generate a third phase current (i.sub.w) such that the first, second and third phase current commands will have a sum equal to zero.
Abstract:
A pulse coder comprises a rotating member (1) on which first and second magnetic patterns (221, 222; 221', 222') are formed and a fixed member (3) on which first and second magnetoresistance patterns (MR5, MR6) are formed. When the first and second magnetic patterns of the rotating member directly face the first and second magnetoresistance patterns, respectively, of the fixed member, the first and second magnetoresistance patterns have a minimum resistance value and a maximum resistance value, respectively. The first and second magnetic patterns are constructed by alternately and irregularly arranging strong magnetic field generating areas and weak magnetic field generating areas.
Abstract:
Disclosed is a motor speed detecting device which comprises a first slotted disc (3) having one slot and mounted on a rotational shaft (2) of a motor (1) that is driven by a motor drive unit (7) and a second disc (4) having a plurality of slots, a first magnetic sensor (5) mounted on the first gear (3) in close proximity thereto and outputting two signals with a phase difference and a second magnetic sensor (6) mounted on the second slotted disc in close proximity thereto and outputting two signals with the phase difference and their inverted signals and a detector circuit (8) receiving the output of the first and the second magnetic sensors. The detector circuit (8) is provided, wherein two outputs from the first magnetic sensor are compared with a differential amplified voltage and a reference voltage, one pulse per one revolution of the rotational shaft (2) is output, and in addition, with the four outputs provided from the second magnetic sensor (6), differential amplification, inverting amplification, comparison and vector synthetic comparison are implemented to provide a pulse per 22.5 degrees, where the phase of the output waveform in the magnetic sensor in response to the width of the slot, resulting in a sinusoidal wave having a different phase by 90 degrees from each other, in response to the number of the slots of the second disc (4), and a square wave of as many as four times the frequencies as the number of slots of the second disc (4) and a square wave of one-fourth period of phase difference with regard to the square wave, are provided to output therewith. Thus, using the relevant device, it is applicable to a to-be-detected rotational shaft of which the rotational shaft (2) is hollow and to provide a precision of detection four times as great.
Abstract:
An inverter circuit having a bridge circuit comprising a plurality of switching elements connected in the form of a bridge for converting, into alternating current, a DC voltage produced by a DC voltage generating unit and which is received through a first switching circuit. The inverter circuit includes a pair of diodes and a spike absorbing capacitor which constitute a series network wherein the diodes are connected so as to be forward biased with respect to the DC voltage and the spike absorbing capacitor is connected between the diodes. The series network is connected in parallel with the bridge circuit and is connected to the DC voltage generating unit through the first switching circuit. The spike absorbing capacitor is connected in parallel with a smoothing capacitor of the DC voltage generating unit.
Abstract:
A mechanism for supporting a cover lid, particularly an original document cover lid of an electrostatic copying apparatus, includes a generally U-shaped support member for supporting the cover lid. A pair of arms of the support member are fixed to a pair of hinge members which are mounted on the machine frame for rotation about an axis. Support pieces are fixed to the hinge members for rotation therewith about the axis. First springs are connected to the support pieces for urging the hinge members, the support member and the cover lid to rotate about the axis in a first direction toward an open position of the cover lid. A revolving plate is pivotally mounted on the machine frame, and a support bar is fixed to one of the hinge members and extends into an elongated opening of the revolving plate, such that rotation of the hinge members around the axis causes the support bar to pivot the revolving plate between first and second positions. An oscillating lever mounted on the machine frame has a projection fitting into the notch when the revolving plate is in the first position and the cover lid is in the open position, such that the projection maintains the cover lid in the open position. A second spring biases the projection against an arc-shaped surface of the revolving plate when the cover lid is moved from the open position toward a closed position thereof.
Abstract:
Disclosed is an induction motor drive apparatus which brings the actual speed of an induction motor into coincidence with a command speed by varying the frequency and effective value of a three-phase AC voltage applied to the induction motor. The apparatus includes an inverter for generating three-phase AC voltage, a speed deviation signal generator, an amplitude controller for controlling the amplitude of the speed deviation signal, an adder for adding together a voltage signal which conforms to the actual speed and the speed deviation signal which has been controlled, a rectangular waveform signal generator, and a pulse width modulator. The rectangular waveform signal generator is adapted to produce a three-phase rectangular signal whose frequency is proportional to the output voltage value of the adder. The rectangular signal of each phase is modulated in pulse width on the basis of the speed deviation, the inverter being controlled by each resulting pulse-width modulated rectangular signal to thereby vary the effective value of the three-phase AC voltage.