Abstract: An ATM communications system has two ring transmission lines in which network nodes are connected for transmission of cells in opposite directions. Each cell contains a first identifier identifying one of the rings and a second identifier identifying a path between source and destination nodes. Each node comprises two subsystems one for each ring transmission lines. Each subsystem includes a multiplexer for forwarding a cell to a first segment of the associated ring and a cell detector for examining the identifiers of a cell from a second segment of the ring to determine its destination. A demultiplexer is normally connected to the second segment of the associated ring for terminating a cell received therefrom or passing it on to the multiplexer depending on the destination determined by the cell detector. A fault on the second segment of the associated ring is detected by a fault detector.

Abstract: A magnetic head having a head core which includes a first head core half body (22) having a winding groove (22b) at one side surface thereof, a second head core half body (23) having one side surface joined with the side surface of the first body, both bodies being fixed by mold glass (25) about a joined plane thereof via a gap spacer (24) of material having a melting point higher than the mold glass, and one end surface (20a) normal to the joined plane and shaped into an arc to become a tape sliding surface having a magnetic gap at the joined plane. The first body has a back groove (22c) formed by cutting out a part near the other end surface opposite to that on which the sliding surface (20a) is formed, and a pair of first track width regulation groove (22d) cut out of both corners of the joined plane and having a slant at a predetermined angle (DEG.sub.1) extending from a portion near the opposite end toward the sliding surface (20a) and transverse to the winding groove (22b).

Abstract: A hub unit having an outer ring member; an inner ring member a flange part, a large diameter part, and a small diameter part which has an outer circumference channel extending circumferentially in an end of the small diameter part and multiple notches which open the outer circumference channel to the end surface of the small diameter part; a sleeve which fits over the small diameter part of the inner ring member, one end of which contacts a shoulder between the large diameter part and the small diameter part and the other end of which overhangs the outer circumference channel; multiple rolling elements positioned at regular intervals between the outer ring member and the large diameter part of the inner ring member and between the outer ring member and the sleeve; and a ring-shaped bayonet member having multiple engaging parts which respectively project radially inward at positions corresponding to the positions of the notches.

Abstract: A belt tensioner comprises a support fixed relative to a belt, a belt engagement device including a pulley being carried by the support and being movable relative to the support, a mechanical spring operatively associated with the support and the belt engagement device for urging the pulley against the belt to tension the belt, and a frictional dampening element operatively associated with the support and the belt engagement device to dampen the movement of the belt engagement device relative to the support in at least one direction of movement. The support being fixed to a fixed portion and including a shaft. The belt engagement device is engaged rotatably around the shaft.