Abstract: An arc welding method which suppresses sputtering and which makes it possible to obtain a smooth bead penetration surface shape as in MIG or MAG welding, without producing undercuts or bumping beads. A carbon dioxide gas welding method effecting welding at welding rates of about not less than 1.

Abstract: An impact and a vibration are applied to a portion of a piston ring on which a belt body is wound, and a vibration is also applied to the belt body. A position where a desired tension can be obtained is obtained by using a master gauge having an outer diameter equal to the inner diameter of a cylinder, and the like. When measuring the tension, a measuring mechanism is moved to this position. The frictional force between the piston ring and the belt body can be considerably decreased, and a closed gap need not be measured every time measurement is performed. Accordingly, the tension of the piston ring can be stably measured at high precision within a short period of time.

Abstract: In a disk drive, the CPU uses the cylinder code recorded on the servo area on the disk and thereby senses the present position of the read head. The cylinder codes are the addresses of the tracks formed on the disk and indicate the track position of the read head. In the servo area, the redundant data for identifying the boundary between adjacent tracks is recorded in addition to the cylinder code. When the read head is located near the track boundary, the CPU receives the cylinder code and redundant data and thereby determines which one of the boundaries with adjacent tracks to the track identified by the cylinder code the read head is located nearby. This makes it possible to determine the present position of the read head even when the read head accurately is positioned near the boundary between adjacent tracks.

Abstract: In a hard disk drive of a sector servo type, two low pass filters having different filter characteristics are used. One low pass filter has uniform group delay characteristics to accurately detect the peak positions of data read/written by a user without causing any peak shifts. The other low pass filter has attenuation characteristics representing a high degree of attenuation of signal components having frequencies higher than a predetermined frequency so as to accurately detect the amplitudes of burst data for positioning a magnetic head to the center of a destination cylinder by removing noise.

Abstract: A hard disk drive includes a head for recording/reproducing data on a recording medium, a motor for moving the head on the recording medium, a motor driver for supplying a driving current to the motor, a data processing circuit for processing data reproduced from the head or record data given to the head, and a cable which has a current line connecting between the motor driver and the motor and a data line connecting between the data processing circuit and the head. The motor has been connected with a noise canceler comprising series-connected first and second filters in parallel with the motor. The connecting point of the first and the second filters of the noise canceler is grounded. A noise generated from the motor driver flows to a ground via the connecting point of the first and the second filters and is cancelled.

Abstract: In a servo system for a hard disk drive, an integrating circuit for eliminating an offset of a head has its capacitor charged to an extent corresponding to an offset amount, at a time of a track following control operation, before an integral action is done. The integrating circuit performs the integral action through the utilization of the charged capacity to eliminate the offset amount of the head. A CPU retrieves an initially prepared offset table for one of voltage level data corresponding to the offset amount which is determined in accordance with a head's destination track. A D/A converter converts the voltage level data which comes from CPU to a voltage and supplies it to the capacitor in the integrating circuit.

Abstract: A recording and reproducing apparatus having reduced power consumption, wherein a spindle motor drive is stopped during a seek operation while a voice coil motor is driven to move a magnetic head to a destination track on a recording medium. Upon the magnetic head reaching the destination track, the voice coil motor drive is stopped, and the spindle motor is driven.

Abstract: A seek operation control apparatus includes first and second position signal generators. By using a position signal from the first position signal generator, the head can be driven and moved before a track position to be moved is designated in the seek mode. After the seek instruction is completely input, the second position signal generator is used to generate a position signal having a predetermined waveform at the track position designated by the seek instruction. When the head comes close to the designated track position, the position signal is switched to accurately move the head to the designated position at high speed.

Abstract: A holder for mounting a split type zero-phase current transformer on an electric wire or cable. The holder has a cylindrical portion made from a flexible material such as a rubber and is provided with a slit extending over the entire axial length thereof. At least one protrusion protrudes inwardly from the inner surface of the cylindrical portion. This holder can be used for a large variety of diameters of electric wire or cable in mounting the split type zero-phase current transformer on such electric wire or cable.