Abstract: A detection signal representing changes of an object observed can be easily transmitted to any desirable site, without performing complex adjustment to use the signal. An AE sensor is provided on an appropriate part of the circumferential surface of a rotating-side chuck which holds a workpiece. A signal-transmitting unit is provided in a space made in the rotating-side chuck. A signal-receiving unit is mounted on an appropriate part of a main section on which the rotating-side chuck is provided. The signal-transmitting unit transmits by radio a detection signal generated by the AE sensor. The signal-receiving unit receives and demodulates the detection signal, generating a signal that will be processed in signal processing.

Abstract: It is possible to stably supply an electric signal to an ultrasonic generation element without causing friction or damage on parts or without requiring periodical parts exchange. A reception coil (11) connected to a vibrator (6) is wound on the outer circumference of a housing (1) constituting a shaft (30) of a machining spindle (101). The reception coil (11) is surrounded coaxially by a transmission coil (12) at an appropriate interval. A predetermined electric signal outputted from an ultrasonic drive device (21) for driving the vibrator (6) is applied to the transmission coil (12). The predetermined electric signal may be applied to the vibrator (6) via the reception coil (11) by electromagnetic induction between the transmission coil (12) and the reception coil (11).

Abstract: To enable detection and transmission of an ultrasonic signal with a high S/N ratio without any need for a component requiring high machining precision or high precision in mounting a component. In a dresser head 41, an ultrasonic sensor 21 detecting an ultrasonic wave is provided, and further provided are: a signal converting/transmitting circuit 23 converting a detected signal of the ultrasonic sensor 21 to a digital signal and subjecting the digital signal to radio modulation; and a signal transmission antenna 26 to which the signal resulting from the radio modulation by the signal converting/transmitting circuit 23 is applied. Further, near the dresser head 41, a signal reception antenna 34 receiving a signal emitted by the signal transmission antenna 26 and a signal reception head 35 demodulating the reception signal obtained by the signal reception antenna 26 are provided, and the demodulated signal is output as a digital signal or an analog signal in a predetermined signal format via a control part 31.

Abstract: In a high pressure seal for a fuel injector formed by bringing a first contact surface of an injector housing to which a first fuel passage is made to open and a second contact surface of a nozzle body to which a second fuel passage is made to open into pressure contact with each other in a connecting portion of the first and second fuel passages, seal grooves of concentric circle form are applied to at least one of the contact surfaces by finish machining, thereby making it possible to suppress effectively the leakage of high-pressure fuel. The first contact surface and the second contact surface may be formed into concave shapes.

Abstract: A detection signal representing changes of an object observed can be easily transmitted to any desirable site, without performing complex adjustment to use the signal. An AE sensor 21 is provided on an appropriate part of the circumferential surface of a rotating-side chuck 4 which holds a workpiece 5. A signal-transmitting unit 101 is provided in a space made in the rotating-side chuck 4. A signal-receiving unit 102 is mounted on an appropriate part of a main section 3 on which the rotating-side chuck 4 is provided. The signal-transmitting unit 101 transmits by radio a detection signal generated by the AE sensor 21. The signal-receiving unit 102 receives and demodulates the detection signal, generating a signal that will be processed in signal processing.

Abstract: A vitrified grinding stone includes an abrasive grain and a vitrified binder. The vitrified grinding stone has a porosity, a degree of concentration of abrasive grains and an abrasive grain diameter according to a preset processing efficiency and a processing precision of grinding.

Abstract: A grinding apparatus according to the present invention grinds a work having a plurality of non-circular work faces to be worked with a grindstone driven by a motor. The work faces are disposed at intervals. Distances between a grindstone unit, bearings and a gear train which are adjacent to each other, are substantially equal to a distance between adjacent work faces of the work. The gear train and the bearings can be respectively positioned between the adjacent work faces of the work in grinding. Therefore, it is possible to prevent interference of the gear train and the bearings with the work faces other than the work face which is being ground by the grinding wheel by a simple structure.

Abstract: A packet switching network in which the data transmitted from a data sending terminal is temporarily stored in a packet switching exchange connected to a data sender where the data is divided into a plurality of units each of which is called a packet and the data in turn is transferred with each packet unit to a packet switching exchange connected to a data receiver, through a number of transmit switching exchanges, and then those packets are reassembled into the original format of the data which finally is transmitted to a data receiving terminal, the above-mentioned packet switching network employing a data sending and receiving system in which a character oriented transmission control procedure for communicating with its associated terminals is used in the packet switching network, and the packet switching network involves data terminals each having a single communication link connected with the packet switching network, whereby the data sending and receiving system is effectively effected and a flow contr