JP2986331B2 - Core drill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core drill used for forming a large-diameter hole.

[0002]

2. Description of the Related Art As a conventional core drill used when opening a large-diameter hole in concrete or the like, a cylindrical core drill body having a cutting edge at a tip, a center drill,
In some cases, the base end of the main body is detachably screwed to the shank, and a center drill is concentrically inserted into the center hole of the shank and fixed by a holo set screw.

[0003]

When a hole is drilled by a core drill, chips are clogged in the core drill body. To remove the chips, it is necessary to remove the core drill body from the shank. In the above-mentioned conventional core drill, in order to remove the core drill body from the shank, the core drill body must be screwed back to the shank. However, there is a center drill attached to the shank in the core drill body, and the core drill must be rotated relative to this center drill, and chips are filled in the core drill body as described above. In such a state, the relative rotation is prevented by the chips, and the core drill body cannot be easily unscrewed.

[0004] Further, since a considerably large rotating torque acts on the threaded portion between the shank and the core drill body, the threaded portion should be elongated in the axial direction to prevent breakage of the threaded portion. However, if the threaded portion is lengthened, the core drill cannot be quickly removed from the shank when the core drill body is unscrewed as described above,
On the other hand, if the threaded portion is shortened so that the core drill can be quickly removed from the shank, there is a problem that the core drill is easily broken.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and has as its object to make it possible to easily and quickly remove a core drill body from a shank even when chips are clogged in the core drill body, and to improve efficiency. It is an object of the present invention to provide a core drill which can be detached from the main body and can surely transmit a turning torque of a shank to a core drill body.

[0006]

According to the present invention, the following technical measures have been taken in order to achieve the above object. That is, the present invention provides a core drill in which a cylindrical core drill body is detachably mounted on a shank, and a center drill concentrically arranged in the core drill body is detachably mounted on the shank. Is inserted into the base end side of the core drill body, and the shank is provided with a locking piece that is removably engaged with the core drill body so as to prevent axial movement in the removal direction of the core drill body. And a torque transmitting member is provided that is axially movable and non-rotatable, and the torque transmitting member is engaged with and disengaged from the core drill body by the axial movement so that the core drill rotates integrally with the shank. And a biasing means for biasing the torque transmitting member so as to engage with the core drill body. It is a symptom.

In the present invention, a shank fitting insertion hole is formed at a base end portion of the core drill body, a distal end side of the shank is removably fitted into the shank fitting insertion hole, and a locking piece is provided at a tip of the shank. A torque transmitting portion may be provided on the outer periphery of the halfway portion of the shank in the axial direction, and the base end portion of the core drill body and the torque transmitting portion may be connected by a torque transmitting member so as to be freely released.

[0008] The torque transmitting member includes a fitting and disengaging operation ring slidably fitted on the shank and a torque transmitting pin provided on the fitting and disengaging operation ring, wherein the torque transmitting pin is provided on the core drill body. It can be inserted in a pin engagement hole parallel to the axis provided in the torque transmission portion of the base end and the shank so as to be able to be fitted and detached. further,
A locking piece insertion groove is provided in the shank fitting insertion hole provided in the base end portion of the core drill main body in parallel with the axis and in a penetrating shape, and a pin provided in the base end portion of the core drill and the torque transmission portion of the shank. The engagement hole may be shifted in the circumferential direction with respect to the locking piece insertion groove.

It is preferable that the center drill is detachably mounted on the shank by being pulled out in the axial direction. For example, a center drill is non-rotatably inserted into a center drill insertion hole formed in a shank, and a ball insertion hole communicating with the center drill insertion hole in a direction orthogonal to an axis line on the shank. A locking ball provided in the ball insertion hole, the locking ball removably engaging with a locking peripheral groove formed in the center drill, and a locking ball engaged with the locking peripheral groove. An urging spring for urging the locking ball may be fitted.

[0010]

[Function] When chips are clogged in the core drill body,
To remove the core drill body from the shank, first, the torque transmission member is moved in the axial direction against the urging force of the urging means to release the engagement with the core drill. Next, if the engagement of the locking piece of the shank with the core drill body is released,
The core drill body can be removed with a single touch by pulling it out in the axial direction without screwing it around the shank.
When the core drill is removed by pulling out in this manner, chips clogged in the core drill main body do not significantly affect the speed and ease of the removal operation.

If the center drill is detachably mounted on the shank by being pulled out in the axial direction, when the core drill body is removed from the shank, the center drill is held by the chips clogged in the body, It can be removed from the shank with one touch with the core drill body. Normally, when performing a hole drilling operation with a core drill, the core drill body is integrally rotated with respect to the shank by a torque transmitting member, and the rotational torque of the shank is reliably transmitted to the core drill body.

In the case where the torque transmitting pin of the torque transmitting member is removably inserted into a pin engaging hole provided in the base end portion of the core drill body and the torque transmitting portion of the shank, an overload occurs in the drill. In addition, the torque transmission pin is sheared and broken. That is, the torque transmitting pin serves as a shear pin. In this case, the torque transmitting member may be replaced, the durability of the entire core drill can be improved, and an electric drill to which the core drill is attached can be used. Device is prevented from being damaged.

[0013] If the pin engagement holes provided in the base end portion of the core drill body and the torque transmitting portion of the shank are displaced in the circumferential direction with respect to the locking piece insertion grooves provided in the shank fitting insertion holes,
When the engagement piece is released from engagement with the core drill body when the core drill body is removed from the shank, the distal end of the torque transmission pin comes into contact with the base end surface of the core drill body. Since the torque transmitting member is urged toward the core drill main body by the urging means, the core drill main body is pushed out of the shank via the torque transmitting pin by the urging force. It will be automatically removed. Therefore, the removal work can be further speeded up and facilitated.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 10 show an embodiment of the present invention. A core drill 1 according to the present embodiment includes a cylindrical core drill body 2 and a center drill 3 concentrically arranged inside the core drill body 2. A shank 4 to which the core drill body 2 and the center drill 3 are detachably attached;
A torque transmitting member 5 for transmitting the rotational power of the shank 4 to the core drill main body 2, a coil spring 6 for urging the torque transmitting member and a C ring 7 for spring engagement, a center drill engagement ball 8, a ball urging coil A spring 9 and a set screw 10 are provided.

The core drill body 2 has a cylindrical shape, a plurality of cutting blades 11 are fixed at its distal end at equal intervals, a shallow spiral groove 12 is provided on the outer peripheral surface, and a shank is inserted into the base end 2A. An inward flange 14 forming a hole 13 is provided, and the flange 14 has a torque transmitting pin engaging hole 1.
5 are provided symmetrically in parallel with the axis, and the fitting hole 13 is provided symmetrically with a locking piece insertion hole 16 at an interval of 90 degrees from the engagement hole 15.

The center drill 3 is a straight shank drill having a normal torsion groove. A hexagonal engagement head 17 is formed at the base end of the straight shank portion 3A, and a locking peripheral groove 18 is provided in the vicinity thereof. ing. As shown in FIGS. 8 and 9, the shank 4 has a fitting portion 4A fitted at one end (upper end) into a holder (not shown) of a boring machine, and a hollow shaft portion fitted with a drill fitting at the other end. 4B, an outer flange-shaped torque transmitting portion 4C is provided on the outer periphery of the shaft portion 4B, and a spring engaging peripheral groove 19 is provided at the upper end of the shaft portion 4B. The ring 7 is fitted.

The shaft portion 4B is provided at its tip with two locking pieces 20 for preventing drill removal at symmetrical positions, the hollow portion is a center drill insertion hole 21, and a hexagonal hole is formed at the bottom of the hole. A drill detent part 22 composed of a hole is formed. The torque transmitting portion 4C is provided with a torque transmitting pin engaging hole 23 displaced in the circumferential direction with respect to the locking piece 20 in parallel with the axis and corresponding to the torque transmitting pin engaging hole 15 of the main body 2. Have been.

Further, the torque transmitting portion 4C of the shank 4 is provided with a ball insertion hole 24 which communicates with the center drill insertion hole 21 from the outer peripheral side. A biasing coil spring 9 is fitted therein, and a holloset screw 10 is screwed therein. The ball 8 projects slightly from the peripheral surface of the drill fitting insertion hole 21 to the center side, and is constantly urged by the spring 9 to be locked. Ball 8
Are fitted and locked in the locking peripheral groove 18 of the center drill 3.

As shown in FIG. 10, the torque transmitting member 5 includes a torque transmitting pin 5A parallel to two axes.
And the shaft 5B of the shank 4
Pin disengagement operation ring 5B externally slidably fitted on the shaft
The coil spring 6 is externally fitted to the shaft portion 4B between the ring 5B and the C ring 7, and the pin engagement / disengagement operation ring 5B is moved by the coil spring 6 in FIG. As shown, the pin 5A is pressed against the end face of the torque transmitting portion 4C of the shank 4 so that the pin 5A
It does not get out of 5,23.

FIGS. 1 to 7 show a state in which the core drill body 2 and the center drill 3 are fitted to the shank 4. The core drill body 2 has the pin transmitting hole 15 into which the torque transmitting pin 5A is fitted. And the shank shaft 4B
A locking piece 20 at the tip is formed and integrated with the inner end face of the inward flange portion 14, and the center drill 3 is
Is inserted into the drill insertion hole 21 and is prevented from coming off by the locking ball 8.

In the above embodiment, when drilling holes in concrete with the core drill 1, if chips are clogged in the core drill body 2, the pin fitting / unlocking operation ring 5B is removed.
By pulling in the direction shown by the arrow (b) in FIG. 1 against the urging force of the coil spring 6 to bring the state shown by the two-dot chain line in FIG. When the core drill body 2 is rotated clockwise or counterclockwise while pulling the pin engagement / disengagement operation ring 5B, the locking pieces 20 coincide with the locking piece insertion grooves 16 of the main body 2.

At this time, since the core drill body 2 is urged by the coil spring 6 via the torque transmitting member 5 in the direction shown by the arrow (a) in FIG.
And the shank shaft portion 4B is pulled out from the shank fitting hole 13 of the main body 2. The center drill 3 is moved by the core drill body 2 by the clogged chips.
And is pulled out of the fitting hole 21 together with the main body 2 against the urging force of the coil spring 9.

In this way, after the core drill body 2 and the center drill 3 are detached from the shank 4 with one touch, chips clogged in the core drill body 2 can be easily discharged. When assembling the core drill 1 again, first, when the center drill 3 is inserted into the center drill insertion hole 21 of the shank 4, the engagement head 1
7 is fitted into the drill rotation preventing portion 22, and the locking ball 8 is fitted and engaged with the locking circumferential groove 18, so that the center drill 3 can be fitted with one touch.

Subsequently, the core drill main body 2 is externally fitted to the center drill 3, and the locking piece insertion groove 16 provided in the base end 2A thereof is fitted to the locking piece 20 of the shank 4, so that the core drill body 2 is mounted. When pressed against the urging force of the coil spring 6 in the direction indicated by the arrow (b) in FIG. 1, the torque transmission pin 5 </ b> A is pushed into the pin engagement hole 12. When the main body 2 is pushed until its base end surface comes into contact with the torque transmitting portion 4C, the locking piece 20 protrudes from the inner end surface of the inward flange 14 of the main body 2, so that the main body 2 is rotated in either the left or right direction. Thus, when the pin engagement hole 15 and the torque transmission pin 5B coincide with each other, the torque transmission pin 5B is pushed through the operation ring 5A by the urging force of the coil spring 6, and the pin engagement hole 15 Fit inside.

Thus, the core drill body 2 can be fitted to the shank 4 with one touch. According to the above-described embodiment, as described above, the core drill body 2 and the center drill 3 can be attached to and detached from the shank 4 with one touch, and the core drill can be removed from the shank 4 by the torque transmitting member 5 having the torque transmitting pin 5A. Since power is transmitted to the main body 2, when an overload acts on the core drill 1, the torque transmission pin 5 </ b> A is sheared, the torque transmission is interrupted, and serves as a torque limiter. Safety can be ensured.

The present invention is not limited to the above embodiment. For example, the locking of the center drill 3 to the shank 4 can be fixed by a holloset screw as in the prior art. Also, the design of the engagement means may be changed as appropriate to provide a one-touch detachable structure.

[0027]

According to the present invention, as described above, the cylindrical core drill body is removably mounted on the shank, and the center drill concentrically arranged in the core drill body is removably mounted on the shank. In the core drill, the shank is inserted into the base end of the core drill body,
The shank is provided with a locking piece that is removably engaged with the core drill body so as to prevent the core drill body from moving in the axial direction in the removing direction. A member is provided, and the torque transmitting member is detachably engaged with the core drill body by axial movement so that the core drill body rotates integrally with the shank, and the torque transmitting member is engaged with the core drill body. The core drill body can be easily and quickly attached and detached efficiently without rotating the core drill body with respect to the shank as in the prior art, because the urging means is provided so as to urge the core drill body. Work efficiency can be improved.

Further, according to the present invention, a shank fitting insertion hole is formed at a base end portion of the core drill body, and a distal end side of the shank is removably fitted into the shank fitting insertion hole. A torque transmitting portion is provided at the distal end and is provided on the outer periphery of the halfway portion of the shank in the axial direction, and the base end portion of the core drill body and the torque transmitting portion are connected by a torque transmitting member so as to be freely released. Is simple and reliable.

Further, according to the present invention, the torque transmitting member includes an engaging / disengaging operation ring slidably fitted to the shank, and a torque transmitting pin provided on the engaging / disengaging operation ring. , The torque transmission pin acts as a shear pin, and is inserted into the pin engagement hole parallel to the axis provided in the base end of the core drill body and the torque transmission part of the shank, so that the torque transmission pin acts as a shear pin and overloads the drill. In the case of occurrence, the pin is sheared, the overload of the core drill is eliminated, the breakage of the core drill is prevented, and the durability can be improved.

Further, according to the present invention, since the center drill is removably attached to the shank by being pulled out in the axial direction, when the chip is clogged in the core drill body, the center drill can be easily removed from the shank together with the core drill body. Can be extracted quickly and efficiently.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional view showing a core drill according to an embodiment of the present invention.

FIG. 2 is a front view of the core drill.

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a bottom view of FIG. 2;

FIG. 5 is a sectional view taken along line AA of FIG. 2;

FIG. 6 is a sectional view taken along line BB of FIG. 1;

FIG. 7 is a sectional view taken along line CC of FIG. 5;

FIG. 8 is a front view of a shank in the core drill.

FIG. 9 is a left side view of FIG.

FIGS. 10A and 10B show a torque transmission member of the core drill, wherein FIG. 10A is a front view and FIG. 10B is a left side view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core drill 2 Core drill main body 3 Center drill 4 Shank 4C Torque transmitting part 5 Torque transmitting member 5A Torque transmitting pin 5B Pin fitting / unlocking operation ring 6 Pin urging coil spring 8 Locking ball 9 Urging spring 13 Shank fitting insertion hole 15 Pin connection Mating hole 16 Locking piece insertion groove 18 Locking peripheral groove 20 Locking piece 21 Center drill insertion hole 23 Pin engagement hole 24 Ball insertion hole

Claims (5)

(57) [Claims] 1. A cylindrical core drill body (2) is detachably mounted on a shank (4), and a center drill (3) concentrically arranged in the core drill body (2) is provided on the shank (4). In the core drill detachably mounted on 4), the shank (4) is inserted into the base end side of the core drill body (2), and the shank (4) has a removing direction of the core drill body (2). In order to prevent axial movement of the core drill body (2), there is provided a locking piece (20) which is removably engaged with the core drill body (2), and the torque transmitting member (5) is movable in the axial direction and is not rotatable. ) Is provided, and the torque transmitting member (5) is detachably engaged with the core drill body (2) by axial movement so that the core drill body (2) rotates integrally with the shank (4). Person in charge A biasing means (6) for biasing the torque transmitting member (5) so as to engage with the core drill body (2); and a shank fitting hole in a base end portion of the core drill body (2). (1
3) is formed, the tip side of the shank (4) is removably fitted into the shank fitting hole (13), and the locking piece (20) is provided at the tip of the shank (4); A torque transmitting portion (4C) is provided on an outer periphery of the shank (4) in the axial direction, and the core drill body (2) is provided.
A core drill, wherein a base end of the core drill is connected to the torque transmitting section (4C) by a torque transmitting member (5) so as to be freely released. 2. A fitting and disengaging operation ring (5B) slidably fitted on a shank (4) of a torque transmitting member (5).
And a torque transmission pin (5A) provided on the engagement / disengagement operation ring (5B), wherein the torque transmission pin (5A)
The core drill body (2) and the torque transmitting portion (4C) of the shank (4) are inserted through pin engagement holes (15, 23) provided in the torque transmission portion (4C) of the shank (4) parallel to the axis so as to be detachable. The core drill according to claim 1, wherein: 3. The core drill according to claim 1, wherein a shank fitting hole (13) provided at a base end of the core drill body (2) is provided with a locking piece insertion groove (16) parallel to the axis and penetrating therethrough. Pin engagement holes (15, 23) provided in the base end portion of the main body (2) and the torque transmission portion (4C) of the shank (4) are displaced in the circumferential direction with respect to the locking piece insertion groove (16). The core drill according to claim 2, wherein the core drill is provided. 4. A core drill body (2) having a cylindrical shape is detachably mounted on a shank (4), and a center drill (3) concentrically disposed in the core drill body (2) is provided on the shank (4). In the core drill detachably mounted on 4), the shank (4) is inserted into the base end side of the core drill body (2), and the shank (4) has a removing direction of the core drill body (2). In order to prevent axial movement of the core drill body (2), there is provided a locking piece (20) which is removably engaged with the core drill body (2), and the torque transmitting member (5) is movable in the axial direction and is not rotatable. ) Is provided, and the torque transmitting member (5) is detachably engaged with the core drill body (2) by axial movement so that the core drill body (2) rotates integrally with the shank (4). Person in charge A biasing means (6) for biasing the torque transmitting member (5) so as to engage with the core drill body (2), wherein the center drill (3) is axially moved by the shank (4). A core drill which is detachably mounted by being pulled out. 5. A center drill (3) is non-rotatably inserted into a center drill insertion hole (21) formed in the shank (4), and is inserted into the shank (4) in a direction perpendicular to an axis. A ball insertion hole (24) communicating with the center drill insertion hole (21), and a locking peripheral groove (18) formed in the center drill (3) in the ball insertion hole (24). Ball (8) removably engaging with the ball
And a biasing spring (9) for biasing the locking ball (8) so that the locking ball (8) engages with the locking circumferential groove (18). The core drill according to claim 4, wherein: