Abstract: A rake face (12) is formed on the both sides of an insert main body facing outside in the thickness direction thereof to make a pair, a cutting edge (14) is arranged on each side which constitutes an outer periphery of the rake face (12), the cutting edge (14) is provided with a major cutting edge (18A) and a minor cutting edge (18B) A connection part (20) formed in a concave curved shape is formed on the insert main body over the entire thickness direction of the insert main body. Of the pair of rake faces (12), each cutting edge (14) on the outer periphery of the first rake face (12A) and each cutting edge (14) on the outer periphery of the second rake face (12B) have rotation symmetry with each other.

Abstract: An arbor for detachably attaching to a main spindle of a machine tool and holding a cutting insert, including: an attachment portion for attaching on the main spindle, which has a cylindrical shape extending along the axis L; a gripping portion extending outwardly of the outer periphery of the attachment portion; and a head holding portion for detachably mounting the cutter head, the head holding portion being positioned on the distal end side of the gripping portion, the head holding portion having a mounting hole extending along the axis L toward the base end side, and the mounting hole having a female threaded portion for threadedly connecting the cutter head, the female threaded portion extending to the base end side of the distal edge of the outer peripheral surface of the gripping portion.

Abstract: A tool main cutting edge extends rearward in a rotating direction as it approaches a rear end at the outer periphery. The main cutting edge is a convexly curved line protruding toward the outside of a rake face viewed from the top and another convexly curved line extending toward the seat face, convexly curving from one end of the main cutting edge to the other, viewed from the side. When mounted, an inclination angle defined by the rake face gradually decreases from one end toward the other, and a projection line of a rotation about a rotation axis of the tool forms a convex arc smoothly coming, at a middle portion of the main cutting edge, into contact with a cylindrical surface about the axis and gradually retreats inward from the cylindrical surface as it approaches both ends of the main cutting edge.

Abstract: A throwaway insert and a cutting tool enable a high speed cutting operation for a metallic material having great ductility such as aluminum and obtaining a vertical wall with a high quality machined surface while improving chip control. The throwaway insert comprises a major cutting edge including a tapered cutting edge connected to a cutting edge of a nose portion, and a curved cutting edge connected to an end of the tapered cutting edge at a connection point. The curved cutting edge is formed so as to extend along an imaginary cylindrical surface whose center axis coincides with the axis of rotation of a tool main body, and tapered cutting edge is formed so as to gradually curve from the imaginary cylindrical surface toward the inside of the imaginary cylindrical surface as the distance from the curved cutting edge increases, and the distance from the nose portion decreases.

Abstract: A throwaway insert and a cutting tool enable a high speed cutting operation for a metallic material having great ductility such as aluminum and obtaining a vertical wall with a high quality machined surface while improving chin control. The throwaway insert comprises a major cutting edge including a tapered cutting edge connected to a cutting edge of a nose portion, and a curved cutting edge connected to an end of the tapered cutting edge at a connection point. The curved cutting edge is formed so as to extend along an imaginary cylindrical surface whose center axis coincides with the axis of rotation of a tool main body, and tapered cutting edge is formed so as to gradually curve from the imaginary cylindrical surface toward the inside of the imaginary cylindrical surface as the distance from the curved cutting edge increases, and the distance from the nose portion decreases.

Abstract: A bridge cable fixing structure, including a fixing plate having multiple cylindrical insertion holes and cylindrical fixing grips corresponding to the insertion holes, each fixing grip being attached to an end of a twisted steel wire. The fixing grips are positioned in the insertion holes on a compression side of the fixing structure, such that the twisted steel wires extend from a tensile side of the fixing structure. When a load is applied to the twisted steel wires attached to the fixing grips, the fixing plate deforms toward the tensile side, compressing the insertion holes against the fixing grips.

Abstract: An object of the present invention is to provide a bridge cable fixing structure in which an outer diameter and a thickness of the fixing plate for use in accepting a tensile load of the cable can be reduced and an anchor socket can be reduced.

Abstract: An armor for a bridge cable including a specified number of trough-shaped metal covers for covering a bridge cable formed of PC steel wire bundles, male and female fitting parts provided on both side edges of the covers for being fitted to each other, and elastic spacers fitted into and connected to the inside of the cover and having concave parts formed thereon for maintaining the PC steel wire bundles in a mass or assembled state. A joint of the cable cover includes a seal member constituted by a specified number of elastic trough-shaped divided bodies for covering the outer periphery of the cable cover by abutting against each other on the side edges thereof, protrusions projecting from the middle of the inside of each divided body for insertion between the facing end edges of the cable covers, and engaging parts projecting from both ends of the outer surface of the divided body.

Abstract: An anchor socket for bridge cables having bundles of stranded steel wires. It has a plurality of ribs formed on its inner wall. The larger the inner diameter of the ribs, the smaller the distance from the point where the cables are fastened.