JPH02167613A - Core drill - Google Patents

Abstract

PURPOSE:To enable a core drill to fulfill a stable function for a long period by withdrawing the core drill, leaving a cut lump in the core body after drilling a large bore hole in a concrete material or the like and permitting the cut lump to be simply taken out of the core body. CONSTITUTION:Respective projections 9 of a coupling ring 7 of a core drill are fitted loosely on a tubular part 3 of a top board 1 through the central part of a inclined surface 4 provided on said tubular part 3. The projections 9 under such condition are inserted in an opening on the upper end of a core body 5. When the top board 1 is twisted relative to the core body 5 in the rotational direction of drilling, the coupling ring 7 expands its diameter as the projections 9 are shifted on the inclined surface 4 so that the outer surface of the coupling ring is forced against and coupled integrally with the inner surface 10 of the upper end opening of the core body 5. After drilling a concrete material or the like, the core body 5 is withdrawn from the drilled hole, leaving a cut lump in said body and the top board 1 is twisted relative to the core body 5 in the opposite direction to said one so that the diameter of the coupling ring 7 is contracted and the top board 1 is removed from the core body 5 to take the cut lump remaining in the core body 5 out of the upper end opening of the core body 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a core drill used to drill a large diameter hole in concrete or the like.

(Prior Art) A wide variety of core drills have been developed and commercially available for drilling large diameter holes.

These core drills are equipped with a drilling blade that is adapted to the object to be drilled in order to improve work efficiency.

By the way, core drills that are used for solidified concrete are commonly used with a structure in which a piercing blade made of a cemented carbide tip is provided at the open lower edge of a cylindrical core body, and the side surface of the piercing blade is attached to the core. It is slightly protruding from both the inside and outside of the body.

(Problems to be Solved by the Invention) As described above, a core drill having a piercing blade provided at the open lower edge of a cylindrical core body protrudes from both the inside and outside surfaces of the core body is used to drill concrete into concrete. When drilling one through hole, a cylindrical cut lump remains inside the core body after drilling, but when this cut lump is extracted from the core body, a drilling blade protruding from the inner surface of the core body remains. This obstructs and makes it difficult to pull out the core body toward the lower end opening side.

Therefore, in order to make it easier to remove the cut lumps remaining in the core body, the core body is configured to be detachable and separate from the top plate that is integrated with the shank, and after drilling, the two can be separated and the cut lumps can be removed. A core drill has also been proposed in which the core body is extracted from the upper end opening of the core body.

However, with this type of conventional core drill, due to the connection structure between the top plate and the core body, it takes time and effort to attach and detach, resulting in poor workability.Additionally, the connection part wears out with repeated use, and the connection relationship between the two deteriorates. This can also cause problems in terms of lifespan.

This invention has been made in view of the above points, and in this invention, it is possible to ensure removal from the hole of the core body while leaving a cylindrical cutting lump in the core body after the operation, To provide a core drill in which cutting lumps remaining in the core body can be easily taken out from the core body, and which exhibits stable functions over a long period of time without any problem in terms of life even in repeated use.

(Means for Solving the Problem) The gist of the present invention to achieve the above object is to include a top plate having a shank at the center of the upper surface, and a cylindrical core body having a perforating blade on the peripheral edge of the opening at the lower end. and an intermediate coupling ring interposed between a coupling cylinder provided on the lower surface of the top plate and the upper end opening of the core body, and a ring is attached at multiple locations on the outer peripheral surface of the cylinder from the tip of the cylinder toward the base. A planar inclined surface with a deep cut is provided, and the coupling ring is provided with a cut that can be freely expanded in diameter, and a protrusion is provided on the inner surface corresponding to the inclined surface of the cylindrical portion, and the outer surface of the coupling ring and the upper end opening of the core body are provided. It is characterized by having a crimp surface formed on the inner surface, and this crimp surface has an uneven slope sloped in the direction in which the coupling ring enters the core body when the top plate is twisted in the drilling rotation direction with respect to the core body. There is a core drill that includes engraving.

(Function) In the core drill configured as described above, 1. Each protrusion of the coupling ring is loosely fitted into the cylindrical portion of the top plate through the central portion of the sloped surface provided on the cylindrical portion.

In this state, when the top plate is inserted into the upper end opening of the core body and twisted in the drilling rotation direction relative to the core body, the protrusion moves on the flat inclined surface toward one end. The diameter of the coupling ring is expanded, and the crimping surface between the outer surface and the inner surface of the upper end opening of the core body is crimped and integrally coupled.

In this way, after drilling work into concrete, etc., the core body is pulled up and removed from Omukai with the cutting mass remaining, and the diameter of the coupling ring is reduced by twisting the top plate relative to the core body in the opposite direction as described above. The top plate is removed from the core body, and the cutting mass remaining in the core body is taken out from the open upper end opening of the core body.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the core drill of the present invention, and FIG. 2 is an exploded perspective view of the top plate and the coupling ring.

In the figure, 1 is a top plate, which has a shank 2 at the center of its upper surface. 3 is a coupling cylinder provided on the bottom surface of the top plate 1;
Planar inclined surfaces 4 are provided at a plurality of locations on the outer peripheral surface of the tube by making deep cuts from the tip of the tube toward the base. This 1-
At the slope 4, the outer edge of the tip of the cylindrical portion forms a straight edge, and the distance (radius) between the axes is the shortest at the center thereof.

Reference numeral 5 denotes a cylindrical core body with a perforating blade 6 provided at the periphery of the opening at the lower end, the perforating blade 6 being made of a cemented carbide chip, and the side surfaces of the core body 5 are made of concrete that slightly protrudes from both the inner and outer surfaces of the core body 5. The structure is adapted to the penetration of

Reference numeral 7 denotes an intermediate coupling ring interposed between the cylindrical portion 3 and the upper end opening of the core body 5, which is provided with a cut 8 that can be expanded in diameter, and has a protrusion 9 on the inner surface corresponding to the inclined surface 4 of the cylindrical portion 3. In the normal state, the inner diameter is slightly larger than the outer diameter of the cylindrical part 3, and when the protrusion 9 is loosely fitted to the cylindrical part 3, the protrusion 9 prevents play between the inclined surfaces 4 near the center of the slanted surface 4 of the cylindrical part 3. Enlarge. In addition, the outer diameter is slightly smaller than the inner diameter of the upper end opening of the core body 5 so that it can be inserted loosely, and this outer surface and the core body 5 that are crimped together.
A crimping surface 10 is formed on the inner surface of the upper end opening, and this crimping surface 10 is provided with an uneven anti-slip process from above to eliminate slippage by crimping the two. As shown in FIG.
In contrast, when the top plate 1 is twisted in the drilling rotation direction, the coupling ring 7 is carved with uneven inclined lines 10a and 10b which are inclined in a direction to enter the core body 5 side.

In the figure, reference numeral 11 indicates a curved edge for holding the coupling ring 7 provided on the outer periphery of the tip of the cylindrical portion, and reference numeral 12 indicates a hole for attaching a center drill provided at the center of the lower surface of the top plate l.

However, when fitting the coupling ring 7 to the cylindrical part 3, the diameter of the coupling ring 7 is slightly enlarged, and the projection 9 is placed at the center of the inclined surface of the cylindrical part 3, that is, at the outer edge of the tip of the cylindrical part, so that the distance between the axes is adjusted. If it passes over the six edges 11 by passing through the shortest straight edge center part, it will be stabilized inside the curved edge 11.

To connect the core body 5, the coupling ring 7 is loosely fitted to the cylindrical part 3, and then the coupling ring 7 is inserted into the upper end opening of the core body 5, and the top plate 1 is twisted relative to the core body 5 in the drilling rotation direction. When turned, the position of the protrusion 9 relative to the inclined surface 4 moves toward the end, strengthening the crimping relationship between the two, and accordingly, the diameter of the coupling ring 7 is expanded, and the outer surface of the coupling ring 7 and the upper end opening of the core body 5 are expanded. The crimping surface 10 on the inner surface of the part is crimped and bonded.

At this time, since the inclined surface 4 deepens the cut from the tip side of the cylindrical portion 3 toward the base, the movement of the protrusion 9 on the inclined surface 3 due to twisting tends to move toward the base of the cylindrical portion 3, and the coupling ring 7
is drawn toward the top plate L side, and the coupling ring 7 enters the core body 5 side by the engagement of the uneven inclined strips 10a and 10b forming the crimp surface 10 on the inner surface of the upper end opening of the core body 5 with the outer surface of the coupling ring 7. Then, the upper opening edge of the core body 5 is firmly pressed against the top plate 1.

The connection between the top plate 1 and the core body 5 is done manually just before drilling the first hole.
! It does not loosen due to rubbing, and when the drilling operation is started, the connection between the top plate 1 and the core body 5 becomes solid and reliable.

(Effects) The core drill of the present invention configured as described above has the following effects.

(1) The top plate and the core body are connected by interposing a coupling ring between them, and by twisting the top plate with respect to the core body, the top plate and the core body are connected on a flat inclined surface provided on the circumferential surface of the cylindrical part on the top plate side. Since the diameter of the coupling ring is enlarged by the movement of the protrusion of the coupling ring, this twisting requires only a small angle, and the coupling operation can be completed almost with one touch, improving work efficiency.

(2) The crimping surface formed on the outer surface of the coupling ring and the inner surface of the upper end opening of the core body is tilted in the direction in which the coupling ring enters the core body side when the top plate is twisted relative to the core body in the drilling rotation direction. Because the grooves and slopes are carved, when the core body is pulled up and removed from the hole after drilling, leaving a cutting lump inside the core body, the core body may accidentally come off from the top plate side due to insufficient crimping. This will not happen and it will be removed without fail.

(3) Since there are no protrusions or screws on the inner surface of the upper opening of the core body, after the core body is removed from the hole after drilling, the top plate is removed from the core body, and the cutting mass remaining inside the core body is removed. It is easy to take out the core body from the upper end opening because there are no obstacles in the way, and even after repeated use, there is no problem with the connection with the top plate due to wear and tear, so the service life is extended. It will be done.

(4) Multiple core bodies can be used in common for one top board as long as the upper end opening dimensions of the core bodies match, so it is possible to drill with different types of punching blades or to use core bodies when the boring blades are worn out. It is convenient for replacing, etc., and is economical and highly versatile.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the core drill of the present invention, Fig. 2 is an exploded perspective view of the top plate and coupling ring, and Fig. 3 is a partially exploded perspective view of the top plate, coupling ring, and core body to which another embodiment is applied. It is a diagram. 1...Top plate, 2...Shank, 3...Cylinder part, 4...
... Inclined surface, 5 ... Core body, 6 ... Penetrating blade, 7 ...
・Coupling ring, 8... Cut, 9... Protrusion, 10.
...Crimping surface, 11...Curved edge, 12...Hole for center drill installation. Figure 3

Claims (2)

[Claims] (1) Between a top plate having a shank at the center of the top surface, a cylindrical core body with a punching blade provided at the periphery of the bottom opening, and a coupling cylinder provided on the bottom surface of the top plate and the top opening of the core body. Consisting of an interposed intermediate coupling ring, the outer peripheral surface of the cylindrical portion is provided with planar inclined surfaces with deep cuts from the tip of the cylindrical portion toward the base, and the coupling ring is provided with cuts that can be freely expanded in diameter. A core drill characterized in that a protrusion is provided on the inner surface corresponding to the inclined surface of the cylindrical portion, and a crimping surface is formed on the outer surface of the coupling ring and the inner surface of the upper end opening of the core body. (2) Between a top plate having a shank at the center of the top surface, a cylindrical core body with a drilling blade provided at the periphery of the bottom opening, and a connecting cylinder provided on the bottom surface of the top plate and the top opening of the core body. Consisting of an interposed intermediate coupling ring, the outer peripheral surface of the cylindrical portion is provided with planar inclined surfaces with deep cuts from the tip of the cylindrical portion toward the base, and the coupling ring is provided with cuts that can be freely expanded in diameter. , a protrusion is provided on the inner surface corresponding to the inclined surface of the cylindrical portion, and a protrusion is provided on the outer surface of the coupling ring and the inner surface of the upper end opening of the core body, when the top plate is twisted in the drilling rotation direction with respect to the core body, the coupling ring 1. A core drill characterized in that a crimp surface is formed by carving an uneven slope sloped in a direction in which the core body enters the core body side.