JPH07100246B2 - Core drill - Google Patents

Description

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

[Prior art]

Conventionally, a wide variety of core drills have been developed and marketed for drilling large-diameter holes, and these core drills have a drilling blade adapted to the material of the object to be drilled.

By the way, in a core drill for a solidified concrete material, a perforating blade made of a cemented carbide tip is provided on the lower end opening peripheral edge of a cylindrical core body, and the side surfaces of the perforating blade are on both inner and outer surfaces of the core body. On the other hand, it has a thick shape with a slight protrusion.

As described above, when a through hole is drilled in a concrete material using a core drill provided with protruding drilling blades on both the inner and outer surfaces of the core body, after the hole is drilled, the core body is hollowed into a cylindrical shape. The cut lump remains, and when the cut lump is pulled out toward the lower end opening side of the core pair, the punching blade portion projecting to the inner surface side of the core interferes and makes the pulling out difficult.

Therefore, in order to facilitate the extraction of the cutting mass from the core body, the core body is configured separately from the top plate that is integrated with the shank, and after the hole is drilled, the two are separated to separate the cutting mass from the core body. There has been proposed a core drill configured to be pulled out from the upper end opening side.

[Problems to be Solved by the Invention]

However, in the conventional core drill in which the top plate and the core body are separate bodies, since a screw structure or the like is adopted for connecting the top plate and the core body, it is troublesome to connect and separate the both, and workability is poor, Further, there is a problem that the screw structure portion is worn out by repeated use, which adversely affects the connection between the two.

The present invention has been made in view of the above points, and the top panel and the core body can be connected / separated by a one-touch method, which is convenient for handling, and the connection relationship does not change even after repeated use, and the reliability is high. The purpose is to provide a core drill with excellent workability.

[Means for Solving the Problems]

The gist of the present invention for achieving the above object is to include a top plate having a shank at the center of the upper surface and a cylindrical core body provided with a perforating blade at the lower end opening peripheral edge. A body mounting portion is formed, and on the peripheral surface of the core body mounting portion,
A peripheral groove is formed to fit an expanding ring having a cutout portion, and a guide groove is provided at a plurality of positions of the peripheral groove inside the expanding ring by gradually decreasing the depth in the circumferential direction, A ball is sandwiched between the guide groove and the expansion ring, and a retaining member having a spherical surface at the tip is freely retractable, which is biased outward by a spring at the core body mounting portion at the incision site of the expansion ring. The upper end opening of the core body into which the core body mounting portion is fitted and has an appropriate width in the circumferential direction, and the lower edge forms an inclined edge. The cutout groove is formed by punching out the engaging hole with which the retaining member protrudes and engages, and the locking pin protruding from the upper end opening edge of the core body at a predetermined depth in the generatrix direction engages with the expanding ring. The core drill is characterized by having a.

[Work]

Align the locking pin with the cut groove, insert the core body mounting part on the top of the core body, and rotate the core body in the opposite direction to the top plate to make the ball roll in the guide groove to the shallower side. Then, the expansion ring is expanded and pressure-bonded to the inner surface of the core pair, so that the top board and the core body are securely coupled.

Further, during the rotation of the core body, the retaining member projects and engages with the engagement hole to stabilize the coupling between the top board and the core body.

Rotational torque from the top plate side in the drilling work is transmitted to the core body through the expansion ring and the retaining member, and stable drilling is performed without rattling.

When the core body is rotated in the direction of the hole with respect to the top plate, the expansion ring is loosened, while the retaining member is pushed by the lower edge of the engagement hole and retracted from the middle of the rotation to release the engagement. Therefore, when the top board and the core body are separated in the axial direction, the two are separated.

〔Example〕

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

FIG. 1 is an exploded perspective view of a core drill of the present invention, FIG. 2 is a front view of a top plate, and FIG. 3 is a plan view of the top plate with a part thereof removed.

In the figure, reference numeral 1 is a top plate having a shank 2 in the center of the upper surface. Reference numeral 3 denotes a core body mounting portion formed on the top board 1, which has a peripheral groove 4 formed on the peripheral surface and a stopper flange 5 on the upper portion.

Reference numeral 6 denotes an expanding ring fitted in the circumferential groove 4 and having a cutout portion 7.

8 is inside the expansion ring 6 at a plurality of positions of the circumferential groove 4,
Guide groove provided with a gradually shallower depth in the circumferential direction, 9
Is a ball sandwiched between the guide groove 8 and the expanding ring 6, and the ball 9 is moved into the guide groove 8 to expand the expanding ring 6.
The expansion of

Reference numeral 10 denotes a locking pin projectingly provided at the end of the expanding ring 6 for connecting a core body, which will be described later, and the expanding ring 6.

Reference numeral 11 denotes a retaining member that is arranged in the cutout portion 7 of the expanding ring 6 so as to be retractable in the core body mounting portion 3. The retaining member 12 is urged outward by the spring 13 in the holding hole 12 to move the ball to the lower outer end. The spherical surface portion 14 is formed by fitting or the like.

Reference numeral 15 denotes a cylindrical core body, and a punching blade 16 made of a cemented carbide chip provided at the lower end opening peripheral edge thereof is a hole for drilling into a concrete material or the like by slightly projecting the side surface with respect to both the inside and outside of the core. The configuration is adapted to.

Reference numeral 17 denotes an engaging hole provided in the upper end opening of the core body 15 in a punched shape corresponding to the retaining member 11 and engaging and disengaging the retaining member 11 and having an appropriate width in the circumferential direction. , The lower edge corresponding to the spherical surface portion 14 is formed with an inclined edge 18 and the long edge of the vertical edges on both sides thereof is formed.
The retaining member 11 is adapted to projectly engage with the engaging hole 17 at a position closer to 19.

Reference numeral 20 is a notch groove provided at a predetermined depth in the generatrix direction from the upper opening edge of the core body 15 corresponding to the locking pin 10.
10 is the one to engage and disengage.

In the above configuration, when the top board 1 and the core body 15 are separated from each other, the ball 9 is located deep inside the guide groove 8 and the expansion ring 6 contracts due to its elasticity, so that the upper opening of the core body 1 is closed. With respect to, free insertion and removal with a small gap open.

To engage the top board 1 and the core body 15, insert the locking pin 10 into the cut groove 20 and insert the core body attaching portion 3 into the upper end opening portion of the core body 15 to open the upper end opening of the core body 15. Edge is spherical
Slidingly contact 14 and push in the retaining member 11 to retract it.

The upper end opening edge of the core body 15 abuts on the stopper collar 5 and the retaining member 11 faces the engaging hole 17, but as shown in FIG. 4 (a), the lower half portion of the retaining member 11 is The slanted edge 18 of the engaging hole 17 keeps it pressed down.

When the core body 15 is rotated with respect to the top board 1 in the opposite direction from the hole in this state, the retaining member 11 is released from being pressed by the core body 15 during the rotation, as shown in FIG. 4 (b). As described above, under the bias of the spring 13, the engaging hole 17 is projectingly engaged, abuts the long edge 19, and the rotation of the core body 15 is stopped.

During this time, the lock pin 10 is locked in the cut groove 20,
The expansion ring 6 moves integrally with the core body 15, and the ball 9 rolls in the guide groove 8 to a shallower direction to expand the expansion ring 6 and crimp it to the inner surface of the core body 15 and the core 1. It is firmly connected to the body 15.

In addition, when the cutting mass remaining inside the core body 15 is extracted after the drilling work for the concrete material or the like is completed, the top board 1 and the core body 15 can be separated by the reverse operation described above, and the opened core body
The cut mass remaining in the core body 15 can be easily removed from the upper end opening of the core 15.

[Effect]

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

(1) The top plate and the core body can be joined / separated by fitting the core body mounting portion of the top plate into the upper end opening of the core body and rotating the core body relatively relatively, so that it can be done with almost one-touch operation. Improve workability.

(2) With the top plate and the core body connected, the expansion ring is pressure-bonded to the inner surface of the core and there is no rattling between the two. Therefore, the torque transmission efficiency in drilling work is improved and the work efficiency is improved. improves.

(3) Since there is no protrusion on the inner surface of the upper end opening of the core body separated from the top plate, there is nothing that obstructs the removal of the cutting mass remaining inside the core body from the upper end opening of the core body after drilling work. The cut mass can be easily taken out, and even if it is used repeatedly, there is no wear or the like, and the service life is extended.

(4) If the joint between the top board and the core is standardized,
Since multiple types of core bodies with different types of punching blades can be shared for one top plate, it is possible to use the core body with different types of drilled objects and core bodies when the drilling blade is worn out. Convenient for replacement, economical and versatile.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a core drill of the present invention, FIG. 2 is a front view of a top plate, and FIG. 3 is a plan view of a top plate with a part cut away.
4 (a) and 4 (b) are operation explanatory views of the retaining member. 1 ... top board, 2 ... shank, 3 ... core body mounting part,
4 ... circumferential groove, 5 ... stopper collar, 6 ... expanding ring, 7 ... incision part, 8 ... guide groove, 9 ... ball, 10
...... Locking pin, 11 …… Retaining member, 12 …… Holding hole, 13
...... Spring, 14 …… Spherical part, 15 …… Core body, 16 …… Drilling blade, 17 …… Engagement hole, 18 …… Inclined edge, 19 …… Long edge, 20 ……
Notch groove.

Claims (1)

[Claims] 1. A top plate having a shank at the center of its upper surface, and a cylindrical core body having a perforated blade at the periphery of the lower end opening. A core body mounting portion is formed on the top plate, and the core body is mounted. A peripheral groove is formed on the peripheral surface of the part, and an expanding ring having a cutout portion is fitted to the peripheral surface, and the depth is gradually reduced in the circumferential direction at a plurality of positions of the peripheral groove inside the expanding ring. A guide groove is provided, a ball is sandwiched between the guide groove and the expansion ring, and the core body mounting portion is urged outward by a spring at a cutout portion of the expansion ring,
A retaining member having a spherical portion at its tip is provided so as to be retractable, and an appropriate width in the circumferential direction is provided at the upper end opening of the core body into which the core body mounting portion is inserted, and the lower edge is an inclined edge. A punching-out engagement hole into which the retaining member projects and engages at a position near one end of the inclined edge, and the expansion ring is formed at a predetermined depth in the generatrix direction from the upper end opening edge of the core body. A core drill having a notch for engaging and disengaging a locking pin protruding from the core drill.