# US 5,915,894 A · Core drill > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,915,894 A - Document ID: US5915894A - Status: Granted - Kind: A - Application number: 08/957,271 - Filed: 1997-10-24 - Granted: 1999-06-29 - Earliest claimed: 1996-11-01 - Assignees: Consec Corporation - Inventors: Kunio Okada; Tatsuo Minaka; Hiroyuki Matsubara - Web page: https://patentgrep.com/patent/US5915894A ## CPC - B28D 1/041: {with cylinder saws, e.g. trepanning; saw cylinders, e.g. having their cutting rim equipped with abrasive particles} - B23B 47/34: Arrangements for removing chips out of the holes made; Chip- breaking arrangements attached to the tool {(chip-breaking in turning machines B23B25/02; in turning tools B23B27/22)} - Y10T 408/554: Magnetic or suction means - Y10T 408/895: Having axial, core-receiving central portion - B28D: WORKING STONE OR STONE-LIKE MATERIALS - B23B: TURNING; BORING (arrangements for copying or controlling B23Q) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A core drill of dry type used for drilling through concrete structure or the like. A main shaft 23 rotatably driven by a motor 33 with a fan 32 is provided with a rubber ring 27 for allowing axial vibration of the shaft, and loosely supported by bearings 25 and 26 with a clearance between them so that it can be slightly tilted in the lateral and transverse directions. During drilling, a spacing between a diamond tip in a leading end of the core bit and a concrete structure or the like is changed as the core bit is moved in the vertical direction and tilted in the lateral and transverse direction, and chips produced by the drilling operation are efficiently discharged by injecting air from the fan 32 through an axial bore 22 in the shaft 23. ## Claims ### Claim 1 A core drill comprising a base fixed to a concrete structure or the like, a pole provided On the base and formed with a rack in a side thereof, a drill head slidably supported by the pole and incorporating a pinion that is engaged by the rack, a core bit removably attached to the drill head for fixing a diamond tip to a leading end thereof, a motor provided in the drill head for rotatably driving the core bit and air suction means for suctioning air inside the core bit or air injection means for supplying air to a drilled portion, wherein a main shaft rotatably driven by the motor and removably attaching the core bit is provided with a damper for allowing vibration in the axial direction of the main shaft. ### Claim 2 A core drill comprising a base fixed to a concrete structure or the like, a pole provided on the base and formed with a rack in a side thereof, a drill head slidably supported by the pole and incorporating a pinion that is engaged by the rack, a core bit removably attached to the drill head for fixing a diamond tip to a leading end thereof, a motor provided in the drill head for rotatably driving the core bit and air suction means for suctioning air inside the core bit or air injection means for supplying air to a drilled portion, wherein a main shaft and the core bit are connected in such manner that they are integrated in the rotating direction, and are slidable with respect to each other only in the axial direction, and a damper is employed between the main shaft and the core bit for allowing vibration in the axial direction of the core bit. ### Claim 3 (depends on 1) A core drill of claim 1, wherein the main shaft is loosely supported by a bearing with a clearance between them for allowing a slight tilt thereof. ### Claim 4 A core drill comprising a base fixed to a concrete structure or the like, a pole provided on the base and formed with a rack in a side thereof, a drill head slidably supported by the pole and incorporating a pinion that is engaged by the rack, a core bit removably attached to the drill head for fixing a diamond tip to a leading end thereof, a motor provided in the drill head for rotatably driving the core bit and air suction means for suctioning air inside the core bit or air injection means for supplying air to a drilled portion, wherein a main shaft rotatably driven by the motor and removably attaching the core bit is loosely supported by a bearing with a clearance between them for allowing a slight tilt thereof. ### Claim 5 (depends on 1) A core drill of claim 1, wherein the air suction or injection means is a fan rotatably driven by the motor. ### Claim 6 (depends on 5) A core drill of claim 5, wherein a flow regulating valve is provided in an air channel. ### Claim 7 A core drill comprising a casing with a handle, a motor contained in the casing and a core bit rotatably driven by the motor, wherein a main shaft rotatably driven by the motor and removably attaching the core bit is provided with a damper for allowing slight movement in the axial direction of the main shaft. ### Claim 8 A core drill comprising a casing with a handle, a motor contained in the casing and a core bit rotatably driven by the motor, wherein a main shaft rotatably driven by the motor and the core bit are connected in such manner that they are integrated in the rotating direction, and are slidable with respect to each other only in the axial direction, and a damper is provided between the main shaft and the core bit for allowing slight movement in the axial direction of the core bit. ### Claim 9 (depends on 2) A core drill of claim 2, wherein the main shaft is loosely supported by a bearing with a clearance between them for allowing a slight tilt thereof. ### Claim 10 (depends on 2) A core drill of claim 2, wherein the air suction or injection means is a fan rotatably driven by the motor. ### Claim 11 (depends on 10) A core drill of claim 10, wherein a flow regulating valve is provided in an air channel. ### Claim 12 (depends on 3) A core drill of claim 3, wherein the air suction or injection means is a fan rotatably driven by the motor. ### Claim 13 (depends on 12) A core drill of claim 12, wherein a flow regulating valve is provided in an air channel. ### Claim 14 A core drill comprising a base fixed to a concrete structure or the like, a pole provided on the base and formed with a rack in a side thereof, a drill head slidably supported by the pole and incorporating a pinion that is engaged by the rack, a core bit removably attached to the drill head for fixing a diamond tip to a leading end thereof, a motor provided in the drill head for rotatable driving the core bit and air suction means for suctioning air inside the core bit or air injection means for supplying air to a drilled portion, wherein a main shaft rotatable driven by the motor and removably attaching the core bit is loosely supported by a bearing with a clearance between them for allowing a slight tilt thereof, and wherein the air suction or injection means is a fan rotatably driven by the motor. ### Claim 15 (depends on 14) A core drill of claim 14, wherein a flow regulating valve is provided in an air channel.