JPH02292107A - Core drill - Google Patents

Abstract

PURPOSE:To join an apical board to a core structure with one touch by providing a holding hole in a core structure fitted portion which is formed on the apical board and loosely holding a joining ball in the holding hole so that the ball can be subsided in the holding hole at a stand-by position and protruded in part from the opening portion of the holding hole at a joined position. CONSTITUTION:In the state of disassembling a core structure 10 from an apical board 1, a ball 8 at a core structure fitted portion 3 is at a stand-by position (A) in a holding hole 5 and protruded in part from an opening 6 under the energization of a spring 9. When the engaging hole 12 of the core structure 10 is matched to the ball 8 to fit the core structure fitted portion 3 into the upper opening portion of the core structure 10, the ball 8 is subsided in the holding hole 5 against the spring 9 and then protruded into the engaging hole 12 again for engagement. The apical board 1 and the core structure 10 are screwed together in this state so that the ball 8 is pushed to the edge of the engaging hole 12 to reach a joined position (B) for joining the apical board 1 to the core structure 10. After punching work is done, the apical board 1 is disassembled from the core structure 10 by the operation opposite to the above to remove cut blocks out of the core structure 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a core drill used for drilling large-diameter holes in concrete and 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 material of 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 configuration in which a drilling 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 drilling blade is attached to the core. It has a thick shape that slightly protrudes from both the inside and outside of the body.

As mentioned above, when drilling a through hole in concrete using a core drill in which the drilling blade provided at the open lower edge of the cylindrical core body protrudes from both the inside and outside of the core body, Later, a cylindrical cut lump that has been pierced remains inside the core body, but when this cut lump is extracted from the core body, the punching blade protruding from the inner surface of the core body interferes with the opening at the lower end of the core body. Makes removal to the side difficult.

Therefore, in order to make it easier to remove the cutting lumps remaining in the core body, the core body is constructed separately from the top plate which is integrated with the shank, and after drilling, the two are separated and the cutting lumps are removed from the core body. A core drill has been proposed in which the core drill is pulled out toward the upper opening side.

(Problem to be Solved by the Invention) However, considering the structure of the conventional core drill in which the top plate and the core body are separate bodies, it takes time and effort to attach and detach the top plate and the core body due to the joint structure of the top plate and the core body. There is a problem that the workability is poor, and the joint part is worn out by repeated use, which affects the joint relationship between the two.

This invention has been made in view of the above points, and provides a core drill that is convenient to handle, in which the top plate and core body can be attached and detached in one-touch, and will not naturally loosen even in the connected state. The purpose is to

(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. A plurality of retaining holes are provided on the outer circumferential surface of the core body attaching portion formed on the top plate, and holding holes are provided in the outer circumferential surface of the attaching portion, and the rolling member for coupling is movable in the circumferential direction within the retaining holes. At the same time as holding the rolling member loosely, the rolling member is provided with a pressurizer that presses the member outward so that a part of the rolling member protrudes from the holding hole opening, and the rolling member is placed in the presser at the standby position set in the holding tag. A part of the rolling member is held in a protruding state from the holding hole opening at the coupling position, and the core body mounting portion is fitted into the upper opening of the core body, so that the rolling member can be sunk into the holding tag. The core drill is characterized in that it has an engaging tab that engages and disengages the core drill.

(Function) In the core drill configured as described above, when the core body is removed from the top plate, the rolling member in the core body attachment part is in the standby position set in the holding hole and is not energized by the compressor. A portion thereof protrudes from the holding hole opening.

When the core body attachment part is fitted into the upper opening of the core body so that the engagement tag of the core body is aligned with the rolling member, the rolling member is temporarily sunk into the holding tag against the depressor, and then is engaged. Re-protrudes into the tag and engages with it.

In this state, when the top plate and the core body are relatively twisted in the rotational direction of the core drill, the rolling member is pushed by the edge of the engagement hole and moves toward the coupling position, and on the way, the maximum force of the presser is applied. The top plate and the core body are joined together by passing through the point and reaching the joining position, where the top plate and the core body are held by preventing free movement by the presser.

In this manner, after drilling a through hole in concrete material or the like, the cutting mass remaining in the core body is removed from the top plate by the above-mentioned operation in the reverse order, and 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 an exploded perspective view of the core drill of the present invention, and FIG. 2 is a cross-sectional view of the main parts.

In the figure, 1 is a top plate, which has a shank 2 at the center of its upper surface. Reference numeral 3 denotes a core body attachment part formed on the top plate 1, and a stopper collar 4 is provided on the upper part thereof. Reference numeral 5 denotes elongated holding holes provided at a plurality of locations on the outer circumferential surface of the core body attachment portion 3 with openings 6 in the outer circumferential surface of the attachment portion 3, and each having an inclined bottom portion 7.

Reference numeral 8 denotes a ball loosely fitted and held in the holding hole 5 so as to be movable and prevented from being pulled out, and a portion of the ball 8 protrudes from the narrow opening 6. 9 is a spring arranged at the bottom 7 of the holding hole 5, which presses the ball 8 outward and holds the pole 8 at the standby position ^ set in the holding hole 5 and the coupling position B; At the standby position A where the depth from the opening 6 is deep, the ball 8 can sink into the holding hole 5 against the spring 9, and at the joining position B where the depth from the opening 6 is shallow, the ball 8 can sink into the holding hole 5. Reference numeral 8 holds a portion of the ball 8 protruding from the opening 6, and the shape of the spring 9 is such that the ball 8 exerts its maximum force while moving between the standby position 8 and the coupling position B. The central part is shaped like a mountain.

Reference numeral 10 denotes a cylindrical core body with a perforating blade 11 provided at the periphery of the opening at the lower end. It has a configuration adapted to drilling holes.

Reference numeral 12 denotes a locking tag that is bored corresponding to the ball 8 in the upper end opening of the core body into which the core body mounting portion 3 is fitted, and that the ball 8 engages and disengages. It belongs to

In the above embodiment, the rolling member is a ball 8, but it may be in the form of a roll or the like. In addition, although the case is shown in which the pressurizer is a spring 9, this is also set to its maximum force so as to hold the rolling member under its force in the holding hole in a manner that prevents free movement between the standby position and the coupling position. It may be made of a suitable rubber member or the like that exerts its force at an intermediate point between the standby position and the coupled position.

When the core drill having the above structure is used, the top plate l and the core body 10 are connected by aligning the engagement hole l2 of the core body 10 with the ball 8 while holding the ball 8 at the standby position A, and aligning the engagement hole l2 of the core body 10 with the ball 8. is inserted into the upper opening of the core body 10, and with the ball 8 protruding and engaged with the engagement hole l2, the ball 8 is moved to the coupling position B by relative twisting between the top plate 1 and the core body 10. and use it in this state.

After the drilling operation, the cylindrical cut lump remaining inside the core body 1O is removed by removing the core body 10 from the top plate 1 in the reverse order of the above procedure, and taking it out from the upper end opening of the core body 10. .

(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 almost one-touch, as all you have to do is insert the core body mounting part of the top plate into the upper opening of the core body and twist the two relatively at a slight angle. This improves work efficiency by completing the joining work in a physically robust and reliable manner.

(2) Since only a plurality of joint holes are drilled in the upper end opening of the core body, there is nothing to obstruct the extraction of the cutting lumps remaining inside the core body after the drilling operation. The cutting block can be easily removed, and even after repeated use, there is no wear and tear that would impede the connection, extending the service life.

(3) By standardizing the joint between the top plate and the core body, multiple types of core bodies with different drilling blade frequencies can be used for one top plate, so the type of body to be drilled can be changed. Drilling holes in the wrong way,
It is convenient to replace the core body when the drilling blade becomes worn out.
Economical and highly versatile.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of the core drill of the present invention, and FIG. 2 is a cross-sectional view of the main parts. DESCRIPTION OF SYMBOLS 1... Top plate, 2... Shank, 3... Core body attachment part, 4... Stopper flange, 5... Holding hole, 6...
...Opening, 7...Slanted bottom, 8...Ball, 9...
・Spring, 10... Cylindrical core body, 11... Perforating blade,
12... Engagement hole, A... Standby position, B... Joining position.

Claims (1)

[Claims] It consists of a top plate having a shank in the center of the upper surface, and a cylindrical core body with a drilling blade provided at the peripheral edge of the opening at the lower end, and a core body attachment part formed on the top plate has a core body attached at multiple locations on the outer circumferential surface of the attachment part. A holding hole is provided with an opening in the hole, and a coupling rolling member is loosely fitted into the holding hole so as to be movable in the circumferential direction, and a presser is disposed to press and force the rolling member outward. A part of the rolling member protrudes from the holding hole opening, and at the standby position set inside the holding hole, the rolling member can resist the presser and sink into the holding hole, and at the coupling position, part of the rolling member is allowed to protrude from the holding hole opening. A core drill that is held in a protruding state and has an engagement hole formed in the upper opening of the core body, into which a core body mounting portion is inserted and the rolling member is engaged and disengaged.