JPH0133631B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a drilling process in which an enlarged hole portion having a diameter larger than the diameter of the pilot hole, that is, an undercut, is cut at a suitable location on the hole wall of a pilot hole that has been previously drilled. It is related to the device.

(Prior art) When installing an anchor bolt in solidified concrete, a blind end hole of a predetermined depth is drilled in the concrete, the base of the anchor bolt is inserted into this hole, and the anchor bolt is inserted in the axial direction. The blind-end cylindrical body with a cut groove (slit) is expanded to create frictional resistance with the hole wall and fixed.

In this way, the pull-out strength of an anchor bolt planted in a concrete surface is largely influenced by the bonding strength between the blind end cylinder and the hole wall, but it is also If the hole wall is correspondingly cut to form an enlarged hole in advance,
The pull-out strength of anchor bolts can be significantly increased. However, using conventional drilling equipment for concrete, that is, normal drilling equipment such as a hammer drill, it is not possible to drill the enlarged diameter hole (inverted conical shape) where the hole diameter widens at the middle or bottom as described above. I can't wait.

Therefore, the same applicant as the present inventor inserted a wedge center into the main body so that it could rotate together with the main body and move relative to the main body in the longitudinal direction under the bias of a spring, and the wedge center was attached to the main body with a common axis. A device has been proposed in which a blade is moved along an overhanging jaw provided at the tip of a wedge center and is configured to protrude outward from the overhanging jaw, and cuts a pilot hole at an appropriate location to create an enlarged diameter hole. has been done. (In addition, there is Japanese Patent Publication No. 36-23856 as a device with a similar configuration.) When using the above device to cut an enlarged diameter hole at the bottom of a blind end pilot hole, for example, the wedge center inserted into the hole is Place the tip of the tool on the bottom of the hole, and in this state, rotate the device to rotate the main body and push the main body into the hole against the spring.
The cutting blade, which was previously located at the base of the overhanging jaw of the wedge center, now extends sideways (radially outward) along the overhanging jaw of the wedge center due to the movement of the main body. The tool moves to the hole wall to cut the hole wall, and eventually reaches the maximum extension point of the overhanging jaw and protrudes outward from the overhanging jaw to cut an enlarged diameter hole in the hole wall. Then, when the pressing force on the main body is released, the cutting blade returns to the position of the base of the overhanging jaw of the wedge center by the action of the spring in the reverse order of the movement described above, and in this state, the device is removed from the hole. It is something that can be pulled out.

(Problems to be Solved by the Invention) However, with the device having the above configuration, there may be the following inconvenience when pulling the device out of the hole after the work is completed. That is, in the case of this device, extraction cannot be performed unless the cutting blade is returned to its normal position at the cutting position in the hole, but it is not possible to pull out the cutting blade until it returns to its normal position at the cutting work position in the hole. In such cases, chips generated by cutting the hole wall often remain without being removed, and it is necessary to prevent the chips from returning to the normal position at the base of the overhanging jaw. This may interfere (deteriorating the return movement of the cutting blade), making it difficult to pull out the device from the hole, or during the pulling operation, chips may get caught in the guide groove, making it impossible to pull out.

This invention was made in view of the above-mentioned points, and when cutting an enlarged diameter hole in a pre-drilled hole in a material to be drilled such as concrete, the tip of the wedge center, on which the cutting blade slides, moves. After gradually protruding laterally from the main body and cutting the enlarged diameter part,
It is an object of the present invention to provide a diameter-enlarging hole cutting device that can be returned into the main body and reliably pulled out from the hole of the device.

(Means for Solving the Problems) The diameter enlarged hole cutting device according to the present invention has a wedge center inserted into a center hole that penetrates through the axial center of the main body up to at least the cutting blade disposed portion, The main body and the wedge center are connected by a locking means such as an elongated hole and an engagement pin so that both can rotate together and move relative to each other in the longitudinal direction, and the wedge center is urged toward the base end of the main body. A spring is interposed between the two, a cutting blade is attached to the side wall of the main body so that it can be housed and protruded, and a sliding contact portion is formed in the wedge center to make sliding contact with the cutting blade, and the wedge center The enlarged diameter hole is configured such that, by movement in the longitudinal direction, the sliding contact portion slides into contact with the inner surface of the cutting blade, so that the cutting blade extends in the radial direction from the stored position and cuts the enlarged diameter portion. In the part cutting device, (a) a shank is placed at the proximal end of the wedge center;
A protruding sliding contact portion such as a ball is formed at the tip, (b) a substantially middle portion of the cutting blade is pivotally attached to the main body by a pivot shaft so that it can be accommodated and protruded, and (c) a sliding contact portion of the wedge center is formed. The inner surface of the cutting blade that makes sliding contact with the contact part has a shape that gradually protrudes inward from the base end to the middle part, gradually recesses outward from the middle part to the tip, and then gradually protrudes inward. It is characterized by forming a sliding surface of

(Function) According to the device of the present invention, the tip of the main body is inserted into a straight pilot hole drilled in advance and rotated until it comes into contact with the workpiece, and in this state,
When the wedge center inserted into the main body is gradually pushed into the main body against the spring, as the wedge center tip moves relative to the main body, the cutting blade attached to the main body slides into contact with the wedge center tip. The contact point of the cutting edge gradually moves toward the tip of the cutting edge. That is, the contact point extends from the proximal end where the cutting blade is housed in the main body, through the intermediate part, and then to the distal end.

Therefore, (1) When the cutting blade is in contact with the sliding part of the wedge center from its base end to the middle part, the base end of the cutting blade gradually moves around its pivot axis. It protrudes radially outward (laterally), and (2) is in contact with the sliding contact part of the wedge center between the most protruding part of the intermediate part and the most concave part of the distal end. , the proximal end of the cutting blade gradually contracts (returns) inward in the radial direction, and (3) is in contact with the sliding contact part of the wedge center from the most recessed part to the tip. Then, the base end of the cutting blade gradually returns to its original state, and finally completely returns to its initial state (stored in the main body).

Therefore, in the process of extending and storing the series of cutting blades in the radial direction, an inverted conical enlarged diameter hole is formed between the sliding contact part of the wedge center and the most protruding part of the middle part from the base end of the cutting blade. is formed, and in the subsequent process, the cutting edge gradually contracts toward the main body and returns to its initial state.

Therefore, in the device of the present invention, by simply pushing the wedge center continuously against the spring, the enlarged diameter hole is cut and the cutting blade is forcibly retracted into the main body, and after the cutting operation is completed, The device can be easily and reliably pulled out of the drilled hole. Therefore, anyone (unskilled person) can obtain an enlarged diameter hole having a desired (predetermined) shape of an inverted cone.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In Figures 1 to 3, 1 is a main body, and 2 is a conical part formed at the tip of the main body, and the outer diameter of the main body 1 is reduced from the approximate middle part of the main body 1 to the base end thereof. Therefore, an engagement stage 3 is provided in the middle part of the main body. The distal end side of this engagement stage 3 becomes a part that is inserted into the pilot hole when cutting the enlarged diameter hole.

Further, a bottomed center hole 4 is bored in the shaft core from the proximal end surface to the distal end of the main body 1. The tip of the center hole 4 needs to reach at least the tip of the cutting blade, which will be described later (more precisely, it must be formed within a range that does not interfere with the sliding contact between the wedge center and the cutting blade). Reference numeral 5 denotes a wedge center, and a protruding sliding contact portion 6 is formed at the tip of the wedge center 5, and in this embodiment, it is formed into a spherical shape to ensure smooth sliding contact.

The wedge center 5 is inserted into the center hole 4 of the main body from the proximal end side. The wedge center 5 and the main body 1 are locked by a locking means so as to be coaxially rotatable and movable in the longitudinal direction. In this embodiment, this locking means is located at the wedge center 5.
A long hole 7 is formed on the side, and a torque transmission pin (locking pin) 8 is installed horizontally between the main body 1 and the wedge center 5 so as to pass through the long hole 7. Of course, this locking means may be constituted by known means such as splines, steps or rings.

Further, a compression spring 10 is interposed between a retaining ring 9 fixed around the upper end of the wedge center 5 and the base end surface of the main body 1 to urge the wedge center 5 toward its base end. Of course, instead of this configuration, a tension spring (not shown) may be used to bias the wedge center toward the proximal end.

11 is a shank, and this shank 11 may be formed integrally with the wedge center 5, but in this embodiment, in order to prevent overload (to prevent damage to the device),
It is formed as a separate member at the upper end of the wedge center 5 and is integrally connected to the wedge center 5 by a shear pin 12 so that it can rotate together.

Reference numeral 13 denotes a pair of plate-shaped cutting blades, and a carbide tip 1 for cutting is provided on the base end side from the middle part of the outer edge of each cutting blade 13.
3a is planted. A vertically elongated opening 1 extending to the center hole 4 is provided in the side peripheral wall of the tip portion of the main body 1.
4 are opened facing each other, and with respective cutting blades 13 disposed in each opening 14, the cutting blades are pivotally connected at approximately the middle portions in the longitudinal direction by a pivot pin 15. Therefore, each cutting edge 13 can freely extend to the side of the main body 1. The inner surface of the cutting edge 13 projects inward from the inner circumferential wall of the main body.

Also, a sliding surface 1 formed on the inner surface of each cutting blade 13 that slides into sliding contact with the sliding contact portion 6 at the tip of the wedge center 5.
3b is formed in such a shape that it gradually protrudes inward from the base end to the middle part, gradually recesses outward from the middle part to the distal end, and then gradually projects inwardly. When the sliding contact part 6 of the wedge center 5 comes into contact with the base end and the tip, the outer surface of the cutting blade is housed in the main body 1, and the most protruding part of the middle part is the wedge center 5. When it comes into contact with the sliding contact portion 6, an inverted conical enlarged diameter hole is formed.

That is, as the sliding contact portion 6 of the wedge center 5 moves toward the distal end along the sliding surface 13b of the cutting blade 13, as shown in FIGS. After gradually extending to the side from the stored state, it gradually moves back to its original position, that is, the stored state (normal position).

16 is a pair or a plurality of spheres for fixing the wedge center 5 at its lowest position;
These spheres 16 are loosely fitted into a through hole 17 formed in the peripheral wall of the intermediate portion of the main body 1 so as to extend up to the center hole 4, with a portion exposed. Then, through hole 1 on the circumferential surface of the main body 1
A spherical pressing sleeve 18 is movably (slidably) disposed around the 7 part, and a compression spring 2 is inserted between the sleeve 18 and a ring 19 fixed around the upper end of the main body 1.
0 to urge the sleeve 18 downward.
In addition, the above-mentioned sphere 1 is provided at the lower part of the inner peripheral surface of the sleeve 18.
An annular groove 18a into which the exposed portion of No. 6 fits is formed in advance.

On the other hand, the circumferential surface of the middle part of the wedge center 5, that is, the through hole 1 which is the most extreme position of its movement.
7 is formed with an annular groove 21 into which a part of the spherical body 16 is fitted with the exposed portion of the spherical body 16 coming out of the annular groove 18a of the sleeve 18. Reference numeral 22 is a stopper of the pressing sleeve 18.

Next, how to use the embodiment of the above configuration will be explained.

As shown in Fig. 5a, when cutting an enlarged diameter hole in a straight hole (prepared hole) A that has been previously drilled, the distal end side of the main body 1 is engaged in this hole A. Insert until the step 3 contacts the upper surface B of the hole A.

From this state, when the wedge center 5 is pushed into the main body 1 against the compression spring 10 while applying rotation to the main body 1 via an electric motor (not shown) connected to the shank 11, the wedge center 5 The spherical sliding contact part 6 at the tip moves downward while slidingly contacting the sliding surface 13b of the cutting blade 13, and unfolds as shown in FIGS. From the state housed in the vertically elongated opening 14 of No. 1, cutting of the wall of the prepared hole starts by gradually protruding outward in the radial direction (outside) until it reaches the most protruding position shown in Fig. 4b above. The wall is cut into an inverted conical shape to form an enlarged diameter hole C as shown in FIG. 5b.

Further, the wedge center 5 is compressed by the compression spring 10.
When the cutting blade 13 is pushed into the main body 1 against the pressure, it returns to its original position as shown in FIG. It is retracted and stored. In this state, the sphere 16 in the through hole 17 of the main body 1 is compressed by the compression spring 20.
The wedge is pushed out of the annular groove 18a by the pressing sleeve 18 under the force of the wedge, and is fitted into the annular groove 21 of the wedge center 5, moving the wedge center 5 to the most extreme position in its movement, as shown in FIG. 5b. Fix it with. Therefore, in this way, the cutting edge 1
3 is fixed in the housed state, and the main body 1 can be pulled out from the hole A after the cutting operation is completed.

After pulling out the main body 1, if the pressing sleeve 18 is moved toward the proximal end against the compression spring 20, the sphere 16 comes out of the annular groove 21 of the wedge center 5 and is no longer engaged with the wedge center 5. The wedge center 5 is released and biased by the compression spring 10 and returned to its original position (the position shown in FIGS. 1 and 5a).

FIGS. 6a to 6c are drawings showing a mode in which a two-stage enlarged diameter hole is cut using the above-mentioned apparatus. According to the device of the above-described embodiment, the length from the engagement step 3 of the main body 1 to the conical end portion 2 is constant, so the depth of the enlarged diameter hole C cut into the hole A is always constant. become.
Therefore, when cutting multiple stages, for example, two-stage enlarged diameter holes C and D, in the same hole A, first cut the lower enlarged diameter hole C as shown in Fig. 6a, and then As shown in FIG. 6b, the depth adjustment ring 23 is inserted from the tip to the tip of the main body 1, and the depth adjustment ring 23 is
By bringing the base end into contact with the engagement step 3 and performing the above-mentioned cutting operation in this state, the enlarged diameter hole D of the second step can be cut. Two-stage enlarged diameter holes C and D can be cut.

(Effects) As explained above, according to the diameter expansion hole drilling device of the present invention, when installing an anchor bolt in concrete etc. It is possible to easily cut a desired inverted cone-shaped enlarged diameter hole in the wall, and the pull-out strength when installing anchor bolts can be significantly improved.
Moreover, by simply pressing the wedge center in one direction, the base end of the cutting blade is forced to gradually protrude laterally from the main body, the enlarged diameter hole is cut, and the base end of the cutting blade is forced again. The device is gradually drawn into the main body and stored, and the device can be reliably pulled out from the hole after the cutting operation is completed.

In this way, the cutting operation is extremely simple, and since each operation is performed continuously by moving the wedge center in one direction, work efficiency is improved and the series of steps from the start of cutting work to the removal of the device is improved. This has the effect that work is carried out smoothly. In particular, it has a great effect that even an unskilled worker can easily cut a desired enlarged hole in the same way as a skilled worker.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 2 is a view taken in the direction of the arrow in Fig. 1, Fig. 3 is a sectional view taken along the line - - in Fig. 1, and Fig. 4 a to d are cutting edges. Fig. 5a is a longitudinal sectional view showing the starting state of the cutting operation, Fig. 5b is a longitudinal sectional view showing the finishing state of the cutting operation, and Figs. 6 a to c are FIG. 3 is a cross-sectional view showing a mode of work for cutting a two-stage enlarged diameter hole. DESCRIPTION OF SYMBOLS 1... Main body, 4... Center hole, 5... Wedge center, 6... Sliding part, 10... Compression spring, 11...
...shank, 13...cutting blade, 13b...sliding surface.

Claims (1)

[Claims] 1. A wedge center is inserted into a center hole that penetrates through the axial center of the main body up to at least the cutting blade disposed portion,
The main body and the wedge center are connected by a locking means such as an elongated hole and an engagement pin so that both can rotate together and move relatively in the longitudinal direction, and the wedge center is urged toward the base end of the main body. a spring is interposed between the two, a cutting blade is attached to the side wall of the main body so that it can be housed and protruded, and a sliding contact portion is formed in the wedge center to make sliding contact with the cutting blade,
By moving the wedge center in the longitudinal direction,
The sliding contact portion slides into contact with the inner surface of the cutting blade,
In an enlarged hole drilling device configured such that the cutting blade protrudes radially from a storage position to cut an enlarged diameter portion, (a) a shank is placed at the proximal end of the wedge center;
A protruding sliding contact portion such as a ball is formed at the tip, (b) a substantially middle portion of the cutting blade is pivotally attached to the main body by a pivot shaft so that it can be stored and extended, and (c) a sliding contact portion of the wedge center is formed. The inner surface of the cutting blade that makes sliding contact with the contact part has a shape that gradually protrudes inward from the base end to the middle part, gradually recesses outward from the middle part to the tip, and then gradually protrudes inward. A diameter expanding hole cutting device characterized by forming a sliding surface.