Abstract: A core cutter includes: a cylindrical body; and a tipped bit that is disposed in a manner to protrude from a distal end of the body. The core cutter is configured to cut a workpiece with the bit when the body is rotated about a rotational axis that is an axis of the body. At a distal end of the body, a notch is formed adjacently to the bit at a position forward of the bit in a rotation direction of the body. A width of the notch in a circumferential direction of the body at the distal end of the body is less than or equal to 1.0 mm.

Abstract: A drilling device for forming an enlarged-diameter hole includes: a guide sleeve with a cylindrical body and a guide to be inserted into a bottomed hole; a slide body that slides in the cylindrical body; and a bit holder provided on the slide body swingably; and a diameter-enlarging bit with a cutting blade. The bit slides between a first position where the cutting blade is separated from a bottom of the bottomed hole and a second position where the cutting blade is closer to the bottom than that at the first position. The guide has: a guide piece that guides the cutting blade to a side part, of the bottomed hole, following an advance of the bit from the first position to the second position; and an opening which allows passage of the bit removed from the bit holder where the bit is at the first position.

Abstract: A hole drilling device for forming an expanded-diameter hole portion at an inner bottom part of a mounting hole includes: a shaft including a contact surface and a tapered surface, and a cutter including a stopper provided on a side surface of the cutter, the stopper coming into contact with a surface of a drilling object. The cutter is movable between a first position and a second position. When the cutter is in the first position, the contact surface is in contact with the inner bottom part of the mounting hole, and the stopper is away from the surface of the drilling object. When the cutter is in the second position, the cutter has been pushed in forward from the first position, the cutting bit has protruded laterally from the tapered surface, and the stopper is in contact with the surface of the drilling object.

Abstract: A dust suction drill includes: a drill tip with cutting edge portions; a shaft joined to the drill tip and configured to rotate about an axis; and a dust suction passage that is generated when the cutting edge portions rotate, the dust suction passage being formed inside the shaft. The cutting edge portions are provided on a distal end surface of the drill tip and spaced apart from each other in a circumferential direction. Cutting edges, each of which is formed by a joint ridge between a rake face and a relief face of a corresponding one of the cutting edge portions, are arranged radially, and at a center of the drill tip, form a chisel point, which is a pointed end. A dust suction hole, which communicates with the dust suction passage, is formed in the rake face or the relief face closely to the chisel point.

Abstract: A hole drilling device for forming an expanded-diameter hole portion at an inner bottom part of a mounting hole includes: a shaft including a contact surface and a tapered surface, and a cutter including a stopper provided on a side surface of the cutter, the stopper coming into contact with a surface of a drilling object. The cutter is movable between a first position and a second position. When the cutter is in the first position, the contact surface is in contact with the inner bottom part of the mounting hole, and the stopper is away from the surface of the drilling object. When the cutter is in the second position, the cutter has been pushed in forward from the first position, the cutting bit has protruded laterally from the tapered surface, and the stopper is in contact with the surface of the drilling object.

Abstract: An anchor bolt inserted in a mounting hole includes: a shaft including an expanded diameter portion formed on its distal end, the expanded diameter portion having a tapered outer peripheral surface; a sleeve, into which the shaft is inserted from the proximal end side of the shaft, such that the sleeve covers an outer peripheral surface of the shaft, the sleeve including an expandable portion, which is configured to bend outwardly along the expanded diameter portion when pushed from an insertion complete state of the shaft; and a fitting piece connecting the shaft and the sleeve. A first recessed groove is formed in a peripheral surface of the sleeve. A ring, which contacts an inner peripheral wall of the mounting hole, is fitted in the first recessed groove.

Abstract: An anchor bolt inserted in a mounting hole includes: a shaft including an expanded diameter portion formed on its distal end, the expanded diameter portion having a tapered outer peripheral surface; a sleeve, into which the shaft is inserted from the proximal end side of the shaft, such that the sleeve covers an outer peripheral surface of the shaft, the sleeve including an expandable portion, which is configured to bend outwardly along the expanded diameter portion when pushed from an insertion complete state of the shaft; and a fitting piece connecting the shaft and the sleeve. A first recessed groove is formed in a peripheral surface of the sleeve. A ring, which contacts an inner peripheral wall of the mounting hole, is fitted in the first recessed groove.

Abstract: A device for drilling a hole with an expanded diameter includes: a body, a shank; a sleeve; a compression spring; a drill bit body; an expanded diameter hole portion forming member attached to a side surface of the drill bit body and configured such that a cutting bit protrudes laterally from the drill bit body when the expanded diameter hole portion forming member moves forward on the side surface; a compression spring, which urges the expanded diameter hole portion forming member rearward relative to the drill bit body; and a cam. The expanded diameter hole portion forming member is configured to move forward on the side surface of the drill bit body owing to rotation of the cam when the body moves forward relative to the sleeve.

Abstract: A drill bit includes a pointed head and a bit shaft. A dust suction passage is formed in the bit shaft. A hole with an opening is formed in the pointed head or in a portion of the bit shaft, the portion being near a distal end of the bit shaft. The bit shaft includes a first portion, the first portion including a core and a rib. The core extends in an axial direction, and is thinner than the pointed head. The rib protrudes radially outward from a side surface of the core, and extends over an entire length of the first portion. The dust suction passage extends through the core in the axial direction.

Abstract: Provided is a method of drilling a hole in a drilling object by using a hole drilling device 1 including: a drill bit 3 including a cutting edge on a distal end thereof; and an electric drill 2, which rotates the drill bit 3, the method including a cutting step of rotating the drill bit 3 to drill a hole in the drilling object in a state where a water-soluble gel coolant is applied to the distal end of the drill bit 3.

Abstract: A dust suction drill includes: a drill tip with cutting edge portions; a shaft joined to the drill tip and configured to rotate about an axis; and a dust suction passage that is generated when the cutting edge portions rotate, the dust suction passage being formed inside the shaft. The cutting edge portions are provided on a distal end surface of the drill tip and spaced apart from each other in a circumferential direction. Cutting edges, each of which is formed by a joint ridge between a rake face and a relief face of a corresponding one of the cutting edge portions, are arranged radially, and at a center of the drill tip, form a chisel point, which is a pointed end. A dust suction hole, which communicates with the dust suction passage, is formed in the rake face or the relief face closely to the chisel point.

Abstract: A drill bit includes a pointed head and a bit shaft. A dust suction passage is formed in the bit shaft. A hole with an opening is formed in the pointed head or in a portion of the bit shaft, the portion being near a distal end of the bit shaft. The bit shaft includes a first portion, the first portion including a core and a rib. The core extends in an axial direction, and is thinner than the pointed head. The rib protrudes radially outward from a side surface of the core, and extends over an entire length of the first portion. The dust suction passage extends through the core in the axial direction.

Abstract: The object of the invention is to provide a hard tip where the nose side has wear resistance and the bonding side has toughness. The chemical composition of sintered hard alloy constituting the hard tip is such that a compounding ratio of WC to Co is substantially the same from the nose side to the bonding side, and a first bonding metal or a second bonding metal has a gradient chemical composition wherein the content of the first bonding metal or the second bonding metal is increased from the nose side to the bonding side, the first bonding metal does not form the eutectic texture with WC, and the second bonding metal has the eutectic temperature with WC over the eutectic temperature of WC—Co sintered hard alloy and the melting point over the liquid phase sintering temperature of WC—Co sintered hard alloy.

Abstract: A coolant supply device attached to an electric drilling tool is configured to supply a coolant to a drilling portion at a distal end of a drill. The coolant supply device includes: a first flange member and a second flange member provided axially on a rotating shaft, the rotating shaft sharing a same axis with the drill, the first flange member being positioned at the drill side, the second flange member being positioned such that the second flange member is more distant from the drill than the first flange member; space formed between the flange members, into which a coolant is injected; a coolant supply passage formed between the first flange member and the drill and guiding the coolant in the space to the drill; and a coolant push-out mechanism configured to push the coolant out of the space toward the coolant supply passage.

Abstract: A device for drilling a hole with an expanded diameter includes: a body, a shank; a sleeve; a compression spring; a drill bit body; an expanded diameter hole portion forming member attached to a side surface of the drill bit body and configured such that a cutting bit protrudes laterally from the drill bit body when the expanded diameter hole portion forming member moves forward on the side surface; a compression spring, which urges the expanded diameter hole portion forming member rearward relative to the drill bit body; and a cam. The expanded diameter hole portion forming member is configured to move forward on the side surface of the drill bit body owing to rotation of the cam when the body moves forward relative to the sleeve.

Abstract: A core cutter includes a tubular body portion and a plurality of cutting blades arranged at a tip end of the body portion at predetermined intervals in a circumferential direction. At least one cutting blade serves as an inner cutting blade, and the remaining cutting blades serve as outer cutting blades. Through grooves penetrate a tip end of the body portion to open toward a tip end side of the core cutter. Each of the cutting blades having the same circumferential-direction size as the through groove. Gullets are configured to discharge the chips, each of the gullets formed by an outer peripheral surface. The cutting blades are welded to through grooves such that a radially inner end of an axial-direction tip end portion of each of the cutting blades coincides with or substantially coincides with a peripheral surface of an axial-direction tip end portion of the gullet.

Abstract: A coolant supply device attached to an electric drilling tool is configured to supply a coolant to a drilling portion at a distal end of a drill. The coolant supply device includes: a first flange member and a second flange member provided axially on a rotating shaft, the rotating shaft sharing a same axis with the drill, the first flange member being positioned at the drill side, the second flange member being positioned such that the second flange member is more distant from the drill than the first flange member; space formed between the flange members, into which a coolant is injected; a coolant supply passage formed between the first flange member and the drill and guiding the coolant in the space to the drill; and a coolant push-out mechanism configured to push the coolant out of the space toward the coolant supply passage.

Abstract: The object of the invention is to provide a hard tip where the nose side has wear resistance and the bonding side has toughness. The chemical composition of sintered hard alloy constituting the hard tip is such that a compounding ratio of WC to Co is substantially the same from the nose side to the bonding side, and a first bonding metal or a second bonding metal has a gradient chemical composition wherein the content of the first bonding metal or the second bonding metal is increased from the nose side to the bonding side, the first bonding metal does not form the eutectic texture with WC, and the second bonding metal has the eutectic temperature with WC over the eutectic temperature of WC—Co sintered hard alloy and the melting point over the liquid phase sintering temperature of WC—Co sintered hard alloy.

Abstract: An outer peripheral surface of a tip end portion of the core body has a tapered surface which is thinner toward the tip end and is edged at the tip end. Recesses 2B are formed at an opening peripheral edge of the tip end portion to attach cutting chips 3. A portion of the core body 2 which is adjacent to a forward portion of each of the recesses in the rotational direction is bent radially inward. Each of the cutting chips 3 has a stepped portion such that a radially inner portion 3a of a forward end portion protrudes forward and a radially outer portion of the forward end portion recedes rearward. A radially inner portion of a rearward end portion of the stepped portion is located forward and a radially outer portion of the rearward end portion is located rearward.

Abstract: A shank attachment device attaches a core drill to a rotating portion of a drill device and includes an arbor and a shank. The arbor is detachably attachable to the rotating portion. The arbor and the shank are detachably attachable to each other. The shank is detachably attachable to the core drill. A stopper engages a groove of the shank to stop a movement of the shank in an axial direction away from the arbor. A rotational torque of the arbor can be transmitted to the shank by engaging a first engaging portion of the arbor with a first engaged portion of the shank. The shank contacts the arbor to stop the movement of the shank in the axial direction toward the arbor.