JP2613644B2 - Core drill - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a core drill used for drilling a large-diameter hole in a concrete material or the like.

(Prior Art) Conventionally, various types of core drills have been developed and commercially available for drilling large-diameter holes.

These core drills are provided with a drilling blade adapted to the drilled body in order to improve work efficiency.

By the way, in the core drill for solidified concrete, a core drill having a structure in which a drilling edge made of a cemented carbide tip is provided at an open lower end edge of a cylindrical core body is generally used, and the side surface of the drilling blade is a core drill. It is slightly protruding from both inside and outside of the body.

(Problems to be Solved by the Invention) As described above, a concrete core material is drilled on a concrete material by using a core drill in which a drilling blade provided at an open lower end edge of a cylindrical core body projects on both inner and outer surfaces of the core body. When drilling a through-hole, after the drilling, there is a cutting mass that has been hollowed out in a cylindrical shape inside the core body, but when extracting this cutting mass from the core body,
The perforation blade protruding toward the inner surface of the core obstructs the extraction to the lower end opening side of the core body.

Therefore, in order to facilitate removal of the cutting mass remaining in the core body, the core body is configured to be detachable separately from the top that is integrated with the shank, and after drilling, the two are separated and the cutting mass is separated. There is also proposed a core drill in which the core is extracted from the upper end opening of the core body.

However, in this type of conventional core drill, the work of attaching and detaching is troublesome due to the connection structure between the top plate and the core body, and the workability is poor. May also have an effect, and there is a problem in terms of life.

The present invention has been made in view of the above-described points, and in the present invention, ensures that the core body is removed from the hole of the core body after the operation, leaving a cutting mass hollowed out in a cylindrical shape in the core body, An object of the present invention is to provide a core drill capable of easily removing a cutting lump remaining in a core body from the core body, and exhibiting a stable function for a long period without any problem in terms of life even when used repeatedly.

(Means for Solving the Problems) The gist of the present invention for achieving the above object is to provide a top plate having a shank at the center of the upper surface and a cylindrical core provided with a perforated blade at the peripheral edge of the lower end opening. Body, an intermediate coupling ring interposed between a coupling cylinder provided on the lower surface of the top plate and an upper end opening of the core body. The connecting ring is provided with a notch to expand the diameter, a projection is provided on the inner surface corresponding to the inclined surface of the cylindrical portion, and the outer surface of the connecting ring and the upper end opening of the core body are provided. A crimping surface is formed on the inner surface of the part, and the crimping surface has an uneven slope which is inclined in a direction in which the coupling ring enters the core body side when the top plate is twisted in the drilling rotation direction with respect to the core body. In the core drill that includes engraving.

(Operation) In the core drill configured as described above, each projection of the coupling ring is loosely fitted into the cylindrical portion through the center of the inclined surface provided in the cylindrical portion of the top plate.

In this state, when the projection is fitted into the upper end opening of the core body and the top plate is twisted in the drilling rotation direction with respect to the core body, the projection moves on a planar inclined surface toward one end thereof. 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 pair is crimped and integrally joined.

Thus, after drilling work on concrete materials, etc.
The core body is pulled up and removed while leaving the cutting mass from inside the hole, the top plate is twisted with respect to the core body in the reverse direction to reduce the diameter of the coupling ring, and the top plate is removed from the core body and remains in the core body. The cut mass is removed from the open upper end opening of the core body.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

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

In the figure, reference numeral 1 denotes a top plate, which has a shank 2 at the center of the upper surface. Reference numeral 3 denotes a connecting cylinder portion provided on the lower surface of the top plate 1. A notch is deeply cut from the tip of the cylinder portion toward the base at a plurality of locations on the outer peripheral surface of the cylinder portion 3 to provide a planar inclined surface 4. . The outer edge of the distal end of the cylindrical portion at the inclined surface 4 forms a straight edge, and the center portion minimizes the distance (radius) between the axes.

Reference numeral 5 denotes a cylindrical core body provided with a piercing blade 6 at the peripheral edge of the lower end opening. The piercing blade 6 is made of a cemented carbide chip, and the side surface thereof is made of concrete having a slightly projecting shape with respect to both the inner and outer surfaces of the core body 5. The configuration is adapted to the perforation.

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 so as to be able to expand in diameter, and a projection 9 on the inner surface corresponding to the inclined surface 4 of the cylindrical portion 3. Under normal conditions, the inner diameter is slightly larger than the outer diameter of
The projection 9 increases the play between the inclined surfaces 4 near the center of the inclined surface 4 of the cylindrical portion 3 when loosely fitted. The outer diameter is slightly smaller than the inner diameter of the upper end opening of the core body 5 so as to be loosely insertable. A crimping surface 10 is formed on this outer surface and the inner surface of the upper end opening of the core body 5 to which the core body 5 is crimped. , This crimp surface
10 has been subjected to uneven anti-slip processing in order to eliminate slippage by pressing both. As shown in FIG. 3, when the top plate 1 is twisted with respect to the core body 5 in the drilling rotation direction, as shown in FIG.
Are inclined in the direction in which they enter the core body 5 side, and the uneven ridges 10a, 10
b is engraved.

In the figure, reference numeral 11 denotes a projecting edge for holding the coupling ring 7 provided on the outer periphery of the distal end of the cylindrical portion, and reference numeral 12 denotes a center drill mounting hole provided in the center of the lower surface of the top plate 1.

However, when the coupling ring 7 is fitted to the cylindrical portion 3, the projection 9 is moved to the center of the inclined surface of the cylindrical portion 3, that is, the distance between the axes at the outer edge of the distal end of the cylindrical portion with the coupling ring 7 slightly enlarged in diameter. When it is passed over the convex edge 11 so as to pass through the center of the straight edge which is the shortest, it is stabilized inside the convex edge 11.

The coupling with the core body 5 is performed by loosely fitting the coupling ring 7 to the cylindrical portion 3 and inserting the coupling ring 7 into the upper end opening of the core body 5, and twisting the top 1 with respect to the core body 5 in the drilling rotation direction. When it is turned, the position of the projection 9 with respect to the inclined surface 4 moves toward the end to strengthen the crimping relationship between the two, whereby 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 The crimping surface 10 on the inner surface of the part is crimped and joined.

At this time, the inclined surface 4 has a deeper cut from the distal end side of the cylindrical portion 3 toward the base, so that the movement of the projection 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 to the top plate 1 side, and a concave / convex inclined strip which forms a crimping surface 10 between the outer surface of the coupling ring 7 and the inner surface of the upper end opening of the core body 5.
By the engagement of 10a and 10b, the coupling ring 7 enters the core body 5 side and presses the upper opening edge of the core body 5 firmly against the top 1.

The connection between the top plate 1 and the core body 5 is manually performed immediately before the drilling operation. However, once the top plate 1 and the core body 5 are connected, they are not loosened due to friction between the members. The connection between the top plate 1 and the core body 5 is firm and secure.

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

(1) The connection between the top plate and the core body is made by interposing a connection ring between the two and connecting the top plate to the core body on a flat inclined surface provided around the cylindrical portion on the top plate side by twisting the top plate. Since the diameter of the coupling ring is increased by moving the projection of the ring, this twisting can be performed at a slight angle, and the coupling operation can be completed almost one-touch, thereby improving workability.

(2) The crimping surfaces formed on the outer surface of the coupling ring and the inner surface of the upper end opening of the core body are inclined in a direction in which the coupling ring enters the core body side when the top plate is twisted in the drilling rotation direction with respect to the core body. Since the concave and convex slopes are engraved, when the core body is pulled up and removed from the hole leaving a cutting mass in the core body after drilling work, the core body comes off from the top side carelessly due to insufficient crimping There is no such thing, and it is reliably extracted.

(3) Since no protrusions or screws are provided on the inner surface of the upper end opening of the core body, after the core body is removed from the hole after the drilling operation, the top is removed from the core body, and the cutting mass remaining in the core body is removed. It is easy to remove it from the upper end opening of the core body without obstruction, and also does not interfere with the connection with the top plate due to wear even with repeated use,
The service life is extended.

(4) As long as the core body has the same upper opening size, a plurality of core bodies can be shared for one top plate, so that a core body with a different type of drilling blade or a worn-out drilling blade is used. It is convenient for exchanging, etc., economical and versatile.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a core drill of the present invention, FIG. 2 is an exploded perspective view of a top plate and a coupling ring, and FIG. 3 is a partially exploded perspective view of a top plate, a coupling ring and a core body to which another embodiment is applied. FIG. DESCRIPTION OF SYMBOLS 1 ... Top board, 2 ... Shank, 3 ... Cylindrical part, 4 ... Inclined surface, 5 ... Core body, 6 ... Perforated blade, 7 ... Coupling ring,
8 ... Cut, 9 ... Protrusion, 10 ... Crimping surface, 11 ... Protrusion, 12 ... Center drill mounting hole.

Claims (2)

(57) [Claims] 1. A top plate having a shank at the center of an upper surface, a cylindrical core body provided with a perforation blade at a peripheral edge of a lower end opening, a coupling cylinder provided on a lower surface of the top plate, and an upper end opening of the core body. An intermediate coupling ring is interposed therebetween, and a flat inclined surface is provided at a plurality of positions on the outer peripheral surface of the cylindrical portion from the tip of the cylindrical portion toward the base portion. A core drill, wherein a projection 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. A top plate having a shank at the center of an upper surface, a cylindrical core body provided with a perforation blade at a peripheral edge of a lower end opening, a coupling cylinder provided on a lower surface of the top plate, and an upper end opening of the core body. An intermediate coupling ring is interposed therebetween, and a flat inclined surface is provided at a plurality of positions on the outer peripheral surface of the cylindrical portion from the tip of the cylindrical portion toward the base portion. Provided, a projection is provided on the inner surface corresponding to the inclined surface of the cylindrical portion, and 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, A core drill characterized in that a crimping surface is formed by engraving a concave and convex inclined strip inclined in a direction in which the coupling ring enters the core body side.