Abstract: A drill includes a cutting edge. The cutting edge has a point angle which is continuously decreased from a center-position point angle A (herein, 0°<A<180°) at a center position to a maximum-diameter-position point angle of 0° at a maximum diameter position. The cutting edge has a relief angle which is continuously decreased from the center position to the maximum diameter position. The cutting edge of the drill has a relief angle at the maximum diameter position. Hence, the cutting edge also serves as a cutting edge for reaming. The ridgeline and relief face of the cutting edge have no corner, thereby providing good wear resistance.

Abstract: A drill includes a cutting edge. The cutting edge has a point angle which is continuously decreased from a center-position point angle A (herein, 0°<A<180°) at a center position to a maximum-diameter-position point angle of 0° at a maximum diameter position. The cutting edge has a relief angle which is continuously decreased from the center position to the maximum diameter position. The cutting edge of the drill has a relief angle at the maximum diameter position. Hence, the cutting edge also serves as a cutting edge for reaming. The ridgeline and relief face of the cutting edge have no corner, thereby providing good wear resistance.

Abstract: A drill includes a cutting edge. The cutting edge has a point angle which is continuously decreased from a center-position point angle A (herein, 0°<A<180°) at a center position to a maximum-diameter-position point angle of 0° at a maximum diameter position. The cutting edge has a relief angle which is continuously decreased from the center position to the maximum diameter position. The cutting edge of the drill has a relief angle at the maximum diameter position. Hence, the cutting edge also serves as a cutting edge for reaming. The ridgeline and relief face of the cutting edge have no corner, thereby providing good wear resistance.

Abstract: A drill includes a cutting edge having a ridgeline. The ridgeline has a part of an ellipse and a straight line. It is assumed that the coordinates of a separation point of an ellipse portion from a straight line portion are (x0, y0). The straight line is a tangent to the ellipse at the separation point. It is assumed that a1 is an area from a tip end of the drill to x0, a2 is an area from x0 to the origin of the ellipse, and a3 is a negative area, along the x-axis. The ridgeline of the cutting edge is formed straight along the tangent in the area a1, and is formed along the ellipse in the area a2. A margin is formed in the area a3 continuously from a relief face of the cutting edge.

Abstract: A drill includes a cutting edge. The cutting edge has a point angle which is continuously decreased from a center-position point angle A (herein, 0°<A<180°) at a center position to a maximum-diameter-position point angle of 0° at a maximum diameter position. The cutting edge has a relief angle which is continuously decreased from the center position to the maximum diameter position. The cutting edge of the drill has a relief angle at the maximum diameter position. Hence, the cutting edge also serves as a cutting edge for reaming. The ridgeline and relief face of the cutting edge have no corner, thereby providing good wear resistance.

Abstract: Within a hood, pressurized cold air is injected from a cold air injection pipe to the spindle and the cutting tool for a machine tool for cooling them and at the same time air is sucked and discharged through a discharge port provided on the hood from the inside of the hood by means of a vacuum pressure produced by a suction device. When air is discharged, a swirl is generated in the hood by discharged air and by deflected air streams passed through a plurality of guide blades provided at the open end of the hood. The cutting chips are floated up by the swirl and discharged together with air through the discharge port.

Abstract: A cooling and dust collecting apparatus for drilling machine tool is disclosed, which comprises a telescopically expandable/shrinkable cylinder having a base cylinder and a movable cylinder, the base cylinder being disposed on the drilling machine in such a manner that the base cylinder surrounds the drilling machine, the movable cylinder being slidably connected to the base cylinder, the movable cylinder surrounding a cutting tool, a blowing pipe connected to an outlet opening portion defined on the movable cylinder, the blowing pipe being adapted for blowing the cutter with cold air, and a sucking pipe connected to an inlet opening portion defined on the movable cylinder, the sucking pipe being adapted for sucking cutting chips and poisonous gas, wherein the movable cylinder has a joint portion, a forward end portion, and an intermediate portion, the joint portion being connected to the base cylinder, the forward end portion surrounding the drill of the drilling machine, the intermediate portion being dispo

Abstract: A cooling and dust collecting apparatus for machine tool for cooling a cutter mounted on a rotating spindle and for sucking and exhausting cutting chips to the outside of the apparatus is disclosed, which comprises a cooling and dust collecting housing surrounding the rotating spindle and the cutter, a plurality of cold air passages, defined inside the housing, for sending cold air of a pressurized cold air supply portion disposed as an external device to a first cold air delivery hole and a plurality of second cold air delivery holes, a cutting chip exhaust passage, defined in the housing, for connecting a cutting chip sucking device disposed as an external device to an inner space of the housing, and an elastic hood downwardly extending from the lower end of the housing, the elastic hood defining slits at the lower end thereof, wherein the first cold air delivery holes are adapted to blow pressurized cold air toward a shaft portion of the cutter, and wherein the second cold air delivery holes are adapted to

Abstract: An aircraft fuselage structure is fabricated by the following steps. A plurality of ring-shaped members are first prepared, each member being provided around the outer peripheral surface thereof at positions spaced apart in the circumferential direction thereof with a plurality of recesses. Elongated plate members are provided which have respective convex parts corresponding to the recesses, to form stringers. The ring-shaped members are then arranged at a coaxially spaced-apart paralleled disposition, and thereafter a laminating jig is inserted into the coaxially arranged ring-shaped members with a silicone bag interposed therebetween, the silicone bag having an open opposite end. The ring-shaped members are placed in annular recesses provided in the laminating jig and in correspondingly formed annular recesses provided in the bag.

Abstract: For forming a resin-impregnated, fiber reinforced composite material sheet having laminated meshes of fibers into a U-shaped cross section, the sheet is placed onto a stationary forming die and an auxiliary forming die with the fibers of the sheet forming angles of approximately 45.degree. relative to opposite edges of an upper reference forming surface of the stationary die. Then, the sheet is pressed from above by a pneumatically expandable, elastic depressing die, whereby the auxiliary forming die is lowered against a resilient force relative to the stationary forming die. As the sheet is pressed further downwardly by the depressing die, the parts of the sheet which are to form flanges of the product are firmly held between the depressing die and the auxiliary forming die and bent downwards while the parts are subjected to extending forces in directions to prevent creases and lines from being formed by means of auxiliary forming ridges on the auxiliary forming die.

Abstract: An aircraft fuselage structure is fabricated by the following steps. A plurality of ring-shaped members are first prepared, each member being provided around the outer peripheral surface thereof at positions spaced apart in the circumferential direction thereof with a plurality of recesses. Elongated plate members are provided which have respective convex parts corresponding to the recesses, to form stringers. The ring-shaped members are then arranged at a coaxially spaced-apart paralleled disposition, and thereafter a laminating jig is inserted into the coaxially arranged ring-shaped members with a silicone bag interposed therebetween, the silicone bag having an open opposite end. The ring-shaped members are placed in annular recesses provided in the laminating jig and in correspondingly formed annular recesses provided in the bag.

Abstract: For forming a resin-impregnated, fiber reinforced composite material sheet having laminated meshes of fibers into a U-shaped cross section, the sheet is placed onto a stationary forming die and an auxiliary forming die with the fibers of the sheet forming angles of approximately 45.degree. relative to opposite edges of an upper reference forming surface of the stationary die. Then, the sheet is pressed from above by a pneumatically expandable, elastic depressing die, whereby the auxiliary forming die is lowered against a resilient force relative to the stationary forming die. As the sheet is pressed further downwardly by the depressing die, the parts of the sheet which are to form flanges of the product are firmly held between the depressing die and the auxiliary forming die and bent downwards while the parts are subjected to extending forces in directions to prevent creases and lines from being formed by means of auxiliary forming ridges on the auxiliary forming die.