Abstract: A three-flute drill includes: three chip discharge flutes; and three cutting edges each having concavely-curved and convexly-curved cutting edge portions, an axially perpendicular cross-sectional view orthogonal to an axial center having first convex and concave curves respectively corresponding to the convexly-curved and concavely-curved cutting edge portions intersecting each other, in the axially perpendicular cross-sectional view, a concave amount of the first concave curve being within a range of 0.01D to 0.05D in terms of a drill cutting diameter relative to a reference line connecting an outer circumferential point, at which a drill outer circumferential portion intersects with the first convex curve, and the axial center, and in the axially perpendicular cross-sectional view, a rake chamfer width being a distance from an intersection between a straight line through the intersection and orthogonal to the reference line and the reference line, to the outer circumferential point, and being within 0.

Abstract: A drill includes: a chip discharge flute opened in a tip surface; and a cutting edge formed at an intersecting portion between an inner wall surface of the chip discharge flute on a side of a drill rotation direction and a tip flank formed on the tip surface, the cutting edge being made up of a concavely-curved cutting edge portion formed on an inner circumferential side and a convexly-curved cutting edge portion formed on an outer circumferential side, a cross section orthogonal to an axial center having a first convex curve corresponding to the convexly-curved cutting edge portion and a first concave curve corresponding to the concavely-curved cutting edge portion intersecting with each other.

Abstract: A three-flute drill includes: three chip discharge flutes; and three cutting edges each having concavely-curved and convexly-curved cutting edge portions, an axially perpendicular cross-sectional view orthogonal to an axial center having first convex and concave curves respectively corresponding to the convexly-curved and concavely-curved cutting edge portions intersecting each other, in the axially perpendicular cross-sectional view, a concave amount of the first concave curve being within a range of 0.01 D to 0.05 D in terms of a drill cutting diameter relative to a reference line connecting an outer circumferential point, at which a drill outer circumferential portion intersects with the first convex curve, and the axial center, and in the axially perpendicular cross-sectional view, a rake chamfer width being a distance from an intersection between a straight line through the intersection and orthogonal to the reference line and the reference line, to the outer circumferential point, and being within 0.

Abstract: A drill includes: a chip discharge flute opened in a tip surface; and a cutting edge formed at an intersecting portion between an inner wall surface of the chip discharge flute on a side of a drill rotation direction and a tip flank formed on the tip surface, the cutting edge being made up of a concavely-curved cutting edge portion formed on an inner circumferential side and a convexly-curved cutting edge portion formed on an outer circumferential side, a cross section orthogonal to an axial center having a first convex curve corresponding to the convexly-curved cutting edge portion and a first concave curve corresponding to the concavely-curved cutting edge portion intersecting with each other.

Abstract: The invention relates to article containment apparatus which is adapted to store articles such as vials on shelves disposed at different elevations by placing them on the successive shelves. In a known article containment apparatus including an elevating mechanism which drives a plurality of shelves, disposed at different elevations for stowing articles thereon, up and down, and a conveyor for conveying articles to a shelf disposed at a given elevation, the invention is characterized by the provision of a plurality of infeeders disposed between the shelf and the conveyor. The infeeders are operated in an alternate fashion so that while one of the infeeders is operating to store articles from the conveyor, another infeeder conveys the stored article thereon onto the shelf. In this manner, there is no need to interrupt the supply of articles by the conveyor during the time the articles are conveyed onto the shelf, thus improving the efficiency of stowage.