JP5419524B2 - Core bit - Google Patents

Description

  The present invention relates to a core bit for a core drill used for drilling concrete structures, stones, asphalt, tiles and the like (herein, these are collectively referred to as a work material).

  A core bit for a core drill includes a coupling screwed into a drill shaft, a tube screwed into the coupling, and a cutting edge screwed into the tube and having a cutting edge made of a diamond tip There is an assembly type that consists of a part (Patent Document 1), and an integral type in which the entire coupling, tube, and blade edge part are integrated.

  As the core drill is thinner, the thickness of the cutting edge can be made thinner, so the cutting volume is reduced, the drilling time can be shortened, and the core drill with low horsepower can be drilled by reducing the load during cutting. There is.

  Comparing the assembly type with the integral type, the former assembly type is connected to the coupling and tube, tube and blade edge by screwing in and screwing in respectively. On the other hand, the latter integrated type has the advantage that the thickness can be reduced by the amount not required to form a screw.

  Since the cutting edge is thicker than the body and protrudes toward the inner and outer peripheral sides, the cutting core of the work material that is cut out and fits in the core bit may be difficult to be caught by the cutting edge. Especially in dry core drills, the diameter of the cutting core increases due to the thermal expansion of the body during cutting, and when the core bit is extracted from the drilling formed in the work material after drilling is completed, the body is somewhat removed. Since it is cooled, the inner diameter of the cutting edge becomes smaller than the outer diameter of the cutting core, which makes it difficult to take out the cutting core remaining in the core bit, and the cutting core in the core bit may have to be crushed and taken out.

  In this regard, the assembly type can be easily taken out by, for example, pushing the cutting core from the cutting edge side of the cutting edge portion to the opposite side by loosening the screw and dividing the core bit into two or three parts even for the dry type. be able to.

JP 2008-87433 A

  The present invention makes it possible to easily take out the cutting core in the core bit by making the core bit into a split type, and reduce the cutting volume and the drilling time by making the wall thickness as thin as the integrated core bit. Another object of the present invention is to provide a core bit that can be drilled even with a low horsepower core drill by reducing the load during cutting.

The core bit of the invention according to claim 1 is connected by being screwed into the shaft of the core drill, and is capable of being removed by screwing the inner periphery and screwing into the coupling. In the core bit which is divided into two parts into a thin shank having a cutting edge at the tip, a zone where a screw is formed in the axial direction and a zone where no screw is formed are provided on the outer peripheral surface of the coupling. In the shank, a screw is formed on the inner peripheral surface of the portion corresponding to the zone where the coupling screw is formed, and the screw is cut on the outer peripheral surface of the portion corresponding to the zone where the coupling screw is not cut. Display means for displaying that the location corresponds to a zone that cannot be displayed is formed.

The invention according to claim 2 is the invention according to claim 1, wherein the core drill is a dry type, and a shaft to which the core drill is connected is attached with a swivel joint connected to a dust collector. The air is sucked into the air, and the cutting edge is cooled by air, and the chips are sucked into the core bit, and the sucked chips are collected together with the air by the dust collector through the hollow portion of the shaft and the swivel joint. The coupling is characterized in that the inner diameter is larger than the screw hole that is screwed into the shaft from the outside, and the tip hits the cutting core to form a stopper that functions to prevent further drilling of the core bit. .

The invention according to claim 3 is the invention according to claim 1, wherein the core drill is a dry type, and a shaft to which the core drill is connected is attached with a swivel joint connected to a dust collector. The air is sucked into the air, and the cutting edge is cooled by air, and the chips are sucked into the core bit, and the sucked chips are collected together with the air by the dust collector through the hollow portion of the shaft and the swivel joint. The coupling has a tapered shape in which at least the inner diameter of the tip portion gradually increases toward the tip, and the tip hits the cutting core to form a stopper that functions to prevent further drilling of the core bit. .

  According to the first aspect of the invention, the core bit is divided into two parts, a coupling and a shank. When the core in the core bit is taken out after completion of drilling, the shank is loosened when it cannot be easily taken out by being caught by the blade edge. It can be easily removed from the opposite side of the cutting edge by removing it from the coupling, and the shank is integrated with the cutting edge and is not divided, so the cutting edge is made thin like an integrated core bit. Therefore, the drilling time can be shortened by reducing the cutting volume and the load during cutting can be reduced, and the core bit at the time of drilling rotates in the direction in which the shank is screwed into the coupling. When the shank is removed, it must be rotated using a tool in the direction to loosen the shank. Even if the shank is strongly gripped and concentrated stress is applied to one or two places, the coupling is thick and highly rigid, so it is difficult to deform, and drilling is performed until the coupling tip hits the core. When hit, no further drilling can be performed, so that the coupling tip functions as a stopper, and the drilling can be regulated to a certain amount.

Moreover, as a tool for rotating the above-mentioned shank, a wrench, a pliers, etc. are used, for example. Examples of the wrench include a wound pipe wrench as disclosed in, for example, JP-A-56-76385, a bell wrench, a chain wrench, various pipe wrench, and the like. The wrench can be used even if the core bit size is slightly different, and there is an advantage that it is not necessary to prepare a dedicated tool for each size. As mentioned above, local concentrated stress acts on the two locations, and if this stress acts on the threaded portion, the coupling will not be deformed and the screw will be crushed and deformed, making it difficult to remove and install the shank thereafter. To. On the other hand, as in the invention according to claim 1 , if a zone in which no screw is formed is provided in the coupling and a display means for displaying a location in which no screw is formed on the outer peripheral surface of the shank, The location displayed by the display means becomes a mark when the shank is gripped by a tool, and when the location is gripped and rotated, even if concentrated stress acts on the location, the screw will not be deformed. There is no hindrance to installation.

According to the second and third aspects of the invention, even in a dry-type core drill in which it is particularly difficult to remove the core from the core bit for the reasons described above, the core is removed from the shank without being broken by removing the shank from the coupling. It is particularly effective as a core bit for a dry-type core drill, and the air sucked into the core drill together with the swarf is decelerated or stalled by a sudden expansion of the cross-section when it is ejected from the core. Therefore, if the core bit is used vertically, the chips are not discharged sufficiently, and if the core bit is used sideways, it gradually accumulates on the shank. When the coupling approaches the core, the tip of the coupling comes to be pressed against the accumulated chips, and when the coupling opening is eventually blocked, the discharge of air and chips is hindered. Despite the remaining drilling stroke, dust cannot be collected, causing troubles such as clogging and seizure of the blade edge and inability to continue drilling due to biting. In this respect, as in the invention according to claim 2 , the inner diameter of the coupling is made larger than the diameter of the screw hole to be screwed into the shaft from the outside, the inner volume of the coupling is widened, or a stopper is provided. As in the invention according to Item 3 , when the stopper is provided by forming the stopper so that the inner diameter of at least the tip of the coupling gradually increases toward the tip, the stopper reaches the end surface of the cutting core, and the hole is formed. It is possible to prevent the above-described trouble from occurring until the stroke is reached.

The front view of a dry-type core drill. The disassembled perspective view of the core bit attached to the core drill shown in FIG. Sectional drawing of the core bit. Sectional drawing of the core bit at the time of drilling. Sectional drawing of the core bit at the end of drilling. Sectional drawing at the time of perforation by another core bit. Sectional drawing when drilling in a horizontal direction using the core bit shown in FIG. Sectional drawing when drilling in the horizontal direction using the core bit shown in FIG.

Hereinafter, a core bit according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a dry-type core drill 2 to which a core bit 1 is attached. The core drill 2 is detachably fixed to a work material 3 and a base 4 protruding from the base 4 to which a rack 5 is attached. A main body 8 provided with a provided support post 6 and a pinion (not shown) that is slidably mounted on the support post 6 and meshes with the rack 5, and is pivotally supported by the main body 8 and provided with a swivel joint 9. Further, a dust collector (not shown) is connected to the swivel joint 9 via a hose 7.

As shown in FIG. 2, the core bit 1 detachably attached to the shaft 11 includes a coupling 14 that is screwed into the shaft 11 and a shank 15 that is screwed into the coupling 14. The coupling 14 is cup-shaped, and includes a flange portion 14a to be screwed into the shaft 11, and a cylinder portion 14b below the flange portion. The cylinder portion 14b has a thickness larger than that of the shank 15 as shown in FIG. Thick and highly rigid, the inner diameter is larger than the screw hole 16 screwed into the shaft 11 from the outside, and the tip is tapered so that the diameter gradually increases toward the tip. The surface is a stopper 13 that functions to prevent further drilling by hitting the upper surface of the cutting core.
The coupling 14 is also divided into a zone 17 where the upper peripheral screw is formed and a zone 18 where the lower screw is not formed.

  On the other hand, the shank 15 is thin as shown in FIG. 3, and a screw is formed on the inner peripheral surface of the location 21 corresponding to the zone 17 where the screw of the coupling 14 is formed. On the outer peripheral surface of the portion 22 corresponding to the zone 18 that is not formed, two annular cut lines 23 as display means are formed above and below the portion 22. When the shank 15 is screwed into the coupling 14, the portion 22 defined by the upper and lower two cut lines 23 corresponds to the zone 18 in which the thread of the coupling 14 is not cut. It has a function to display that it is a location corresponding to.

The drilling of the work material with the core bit is possible until the stopper 13 hits the upper surface of the cutting core, and the portion corresponding to the coupling 14 protrudes from the work material with the stopper 13 hitting the upper surface of the cutting core. In order not to enter, the display means described above may be formed by a protrusion instead of the cut line 23, and a portion corresponding to the zone 18 may be a thick protrusion. Moreover, you may comprise a display means by sticking a sticker or color-coding.
The shank 15 also has a cutting edge 25 formed by a diamond tip at the tip.

  The core bit according to the present embodiment is configured as described above, and the drilling of the work material 2 is performed by sending the core bit 1 at a constant speed while being rotated in a conventional manner. From FIG. 5, when the stopper 13 at the tip of the coupling hits the upper surface of the cutting core, no further drilling can be performed and the drilling can be regulated to a certain amount (the shank length under the coupling).

  At the time of drilling, air is sucked into the core bit from outside the core bit by the suction action of a dust collector (not shown), and chips generated at the time of drilling are sucked, and the cutting edge 25 at the tip of the core bit is cooled by air. The swarf sucked into the core bit together with air is collected by the dust collector through the hollow portion of the shaft 11, the swivel joint 9, and the hose 7.

  During drilling, the air spouted from the periphery of the core 27 together with the chips is decelerated due to the sudden expansion of the cross section, so that a part of the chips overcomes the discharge flow by its weight and gradually piles up on the core. It will be accumulated. When the stopper 13 at the tip of the coupling hits the cutting core 27 as shown in FIG. 5 and reaches the drilling stroke, the opening at the tip of the coupling is blocked by the chip 19 of the chip, and until then the chip and air Can be discharged.

  When the core 27 in the core bit is taken out after the drilling, the core bit 1 is removed from the shaft 11, and the shank 15 is gripped at the portion 22 defined by the cut line 23 using a tool such as a wrench, and the screw is tightened. The shank 15 is rotated in the loosening direction to remove the shank 15 from the coupling 14. Even when concentrated stress is applied to one or several places when the part 22 is gripped with a tool, the coupling 14 does not deform because it has high rigidity. Moreover, since the screw | thread is not formed in the said location 22, the problem that a screw | thread is crushed by stress concentration does not arise. After the shank 15 is removed from the coupling 14, the core 27 in the shank is struck from the blade edge 25 side and pushed out from the opposite side.

FIG. 6 shows another example of the core bit. The coupling 31 is thick and has a funnel shape in which the inner diameter gradually increases from the root having the same diameter as the screw hole 32 toward the tip. Other configurations are the same as the core bit 1 shown in FIG.
4 to 6 show examples in which drilling of the work material 3 is performed in the vertical direction.

  FIGS. 7 and 8 show an example of drilling in the horizontal direction using the core bit 1 shown in FIGS. 3 and 6 described above. In this case as well, chips accumulate on the shank, and the core bit 1 is drilled. As the accumulated amount increases, it is pushed out to the couplings 14 and 31 side, but the coupling is expanded until the drilling stroke of the core bit 1 is reached by widening the internal volume of the coupling or forming the section in a funnel shape. 14 and 31 are not clogged with chips of chips, and the chips and air can be sucked and discharged.

1 .. Core bit 2.. Core drill 3. Work material 4. Base 6. Post 8. Main body 9 Swivel joint 11 Shaft 12 Motor 13 Stoppers 14 and 31 Coupling 15 ·· Shank 16, 32 ·· Screw holes 17, 18 · · Zone 19 · · Chips 21 and 22 · · Corresponding zone 23 · · Cut line 25 · · Cutting edge 27 · · Core

Claims (3)

A thick-walled coupling that is screwed into the core drill shaft and threaded on the outer periphery, and a screw that is threaded into the inner periphery and screwed into the coupling to be removable, with a cutting edge at the tip In a core bit that is divided into two thin shanks, the outer peripheral surface of the coupling is provided with a zone in which screws are formed in the axial direction and a zone in which no screws are formed, while the shank has coupling screws. Screws are formed on the inner peripheral surface of the portion corresponding to the zone to be formed, and the outer peripheral surface of the portion corresponding to the zone where the screw of the coupling is not cut is a portion corresponding to the zone where the screw is not cut Core bits characterized in that display means for displaying is formed .   The core drill is a dry type, and a swivel joint connected to a dust collector is attached to the shaft to which the core drill is connected. During drilling, air is sucked from the outside of the core bit through the drilled hole into the core bit, thereby air-cooling the cutting edge and cutting chips. Is sucked into the core bit, and the sucked chips are collected together with air by the dust collector through the hollow part of the shaft and the swivel joint, and the coupling is a screw whose inner diameter is screwed into the shaft from the outside. 2. The core bit according to claim 1, wherein the core bit has a diameter larger than that of the hole and has a tip that hits the cutting core to form a stopper that functions to prevent further drilling of the core bit. The core drill is a dry type, and a swivel joint connected to a dust collector is attached to the shaft to which the core drill is connected. During drilling, air is sucked from the outside of the core bit through the drilled hole into the core bit, thereby air-cooling the cutting edge and cutting chips Is sucked into the core bit, and the sucked chips are collected together with air to the dust collector through the hollow portion of the shaft and the swivel joint. At least the inner diameter of the coupling gradually moves toward the tip. 2. The core bit according to claim 1, wherein the core bit has a taper shape that expands, and a tip that hits the cutting core to form a stopper that functions to prevent further drilling of the core bit.