JP6678940B2 - Expanding drilling tool - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is a diameter-enhancing drilling tool for underground excavation, which is capable of drilling medium-small diameter holes in vertical, horizontal, and diagonal directions in the ground, and enables drilling with the diameter expanded at the tip or in the middle of the hole. With regard to the above, the technology is characterized by strength and a durable structure particularly in the expanded diameter portion.
This type of diameter-expanding drilling tool is used for drilling so as to expand the diameter at the tip or in the middle position of the underground drilling hole, and after pulling out the diameter-expanding drilling tool, the steel rod is placed in the empty space of the drilling hole or in the drilling hole. It is used for civil engineering to strengthen the ground by injecting cement-based hardening material into the hole-drilling space into which holes etc. are inserted, or to harden the hardening material in the diameter-expanded hole-drilling space for strong anchoring and root consolidation. .

  A small-diameter excavating tool applies a pressing force and a rotating force to the head of the tool, excavates the ground with a tip attached to the tip, and a part of the tip of the tool is rotated or from above. BACKGROUND ART Excavating tools are widely known in which a diameter of a ground is expanded by an operation force and a hole is drilled with a diameter of the ground. Inventions of Patent Documents 1 and 2 are known as tools of this type.

In the invention of Patent Document 1, an auxiliary bit is pivotally supported by a tightening bolt on each of upper and left sides of a plate-shaped bit main body, and the auxiliary bit is expanded around a tightening bolt of the pivot to expand the diameter of the auxiliary bit. It is a structure that enables drilling of the hole diameter.
However, in the invention of Patent Document 1, when the auxiliary bit is rotated with the diameter expanded, it receives a strong resistance from the ground, and the auxiliary bit is not engaged so that the auxiliary bit is strongly attracted to the bit body. There is a possibility that the auxiliary bit may be deformed or a high load may be applied to the tightening bolt of the auxiliary bit and the tightening bolt may be damaged, causing the auxiliary bit to come off the tightening bolt.

Next, the invention of Patent Document 2 is a cutter device having a structure in which a cutter is pivotally supported on both side surfaces of an intermediate portion of a cutter body provided with a pilot plate at its tip end so as to offset the pivot points to opposite sides in the expanding direction. is there. In this invention, a stopper for guiding the rotation of the cutter to the lower side surface is provided in an inclined shape. This facilitates the expanding operation in the initial stage of perforation.
However, also in the invention of Patent Document 2, when the cutter is expanded at a large angle, a strong rotational moment due to a reaction force from the underground ground acts on the cutter at a right angle, and the cutter is attracted to the cutter body against the strong rotational moment. The cutter may be deformed or damaged because it is not a joint structure.

  Further, in Patent Document 3, the lower portion of the cylindrical portion is divided into three bodies by a vertical surface, the middle portion is a plate-shaped excavating tool body, and a movable blade body of an arc portion is provided on the left and right sides thereof by a shaft portion above it. It is pivotally supported, and a convex portion is provided on the divided surface of the excavating tool main body, and a concave portion which is slid toward the movable blade body and fitted into the convex portion is provided. An invention of a structure that fits in a section is disclosed. Small edges of the tenon joints that engage with each other are formed on the fitting peripheral edges of the convex portions and the concave portions, and the edges of the convex and concave tenon joints that engage with each other are inserted into each other so that It is locked so as not to separate in the direction. However, it is difficult for the edge part of the tenon joint of the present invention to engage with the entire surface in contact with the edge part unless the step part is manufactured with extremely high accuracy, and the edge part is engaged with part of the contact. Therefore, there is a problem in that the engaging force is weak with respect to the load of the outward force perpendicular to the engaging direction. Further, in the present invention, there is only one set of protrusions and recesses to be fitted, and the engagement force is only the engagement force by the edge of the U-shaped outer peripheral length of the one protrusion, and the engagement force is sufficient. Not. In the severe use of the present invention in the ground, a strong load acts on the edge portion, and the deformation / displacement of the portion becomes large, which makes it difficult to engage the step itself.

JP-A-55-52497 JP-A-58-191892 JP, 2013-227766, A

  The problem to be solved by the present invention is to solve the problems of the prior art and to have a high engaging force that can sufficiently withstand a strong load and rotational moment at the time of excavation that the expanded diameter cutter and cutter receives from the ground. It is intended to provide a diameter-expanding drilling tool with high durability, with little deformation and damage of the joint portion.

The configuration of the present invention that solves the above problems is
1) A head part capable of loading a pressing force and a rotational torque is provided above the cylindrical body, and a holed part having a plurality of chips attached downward is provided on the bottom bottom surface of the cylindrical body. It is a diameter expansion drilling tool that expands and contracts the outer diameter of a part of the hole according to the direction of rotation, and rotates it in the direction to expand the hole to enable underground excavation with a wide width underground. hand,
The shape of the lower part integrally manufactured with the head part by dividing the lower part of the cylinder part including the drilled portion below the head part of the cylinder part into three parts on the vertical surface in the axial direction of the cylinder part. Is a substantially plate-shaped intermediate portion, a left circular arc portion on the outside thereof, and a right circular arc portion on the opposite side of the outer portion thereof are formed into three parts, and the intermediate portion, the left circular arc portion and the right circular portion are formed. A plurality of chips are projected downward at each of the lower ends of the circular arc portions, and the left circular arc portion and the right circular arc portion are positioned above the dividing planes on both the left and right below the head of the intermediate portion, and the axis of the cylindrical body is The left circular arc portion and the right circular arc portion, which are rotatably pivoted by pivot pins that are eccentric to each other in opposite directions from the core line and are rotatable about the pivot pins, face each other. The dividing surface of the middle part is a pair of upper and lower circular arcs centered on the pivot pin. Along the inner circumference and at the position of the outer diameter of the cylindrical body, and are arranged in a U-shape connecting the starting ends in the center of the dividing surface of the arc line of the set, and a plurality of sets are provided in a state of being vertically separated. It is connected slidably along the dividing surface by the unevenness of the dovetail groove, and the rotation around the pivot pin of the left and right circular arc parts is within a predetermined maximum expansion angle from 0 ° without expansion. A diameter-expansion excavating tool characterized in that stopper means for restricting rotation angle is provided between the left and right circular arc portions and the intermediate portion. 2) Each of the left and right dividing surfaces of the intermediate portion is thin and the upper surface is the dividing surface. A plurality of convex portions that are parallel to each other are provided at intervals in the vertical direction of the dividing surface, and the convex portion is an arc centered on an eccentric pivot pin of the left or right circular arc portion facing the dividing surface. It has upper and lower peripheral edges along the line and The left and right regions, which are opposite to the left and right regions, are located closer to each other, and the back faces of the left and right circular arc portions facing the dividing surface of the intermediate portion are fitted in the valley spaces between the separated convex portions of the intermediate portion. Further, an arm-shaped fitting convex portion whose tip extends to the outer diameter position of the intermediate portion in a reduced diameter state is provided, and the outer peripheral upper edge of the convex portion of the uppermost intermediate portion and the intermediate portion above the uppermost convex portion are provided. In the reduced diameter state, and between the outer peripheral lower edge of the convex portion of the lowermost intermediate portion and the thick portion of the intermediate portion below the lowermost convex portion. Upper and lower outer convex portions respectively extending to the outer diameter position of the intermediate component are provided, and the outer peripheral edge portion of the outer convex portion and the outer peripheral upper edge or outer peripheral lower edge of the uppermost lower convex portion are engaged with each other vertically. On the other hand, the peripheral edges of the fitting convex portion and the convex portion of the intermediate portion are in contact with each other with a dovetail groove structure and the fitting convex portion. The diameter-increasing excavation tool according to the above 1), wherein the tapered inclined surface of the peripheral edge is located below the dovetail groove. 3) The left and right circular arc portions are rotated around the pivot pin to expand the diameter. The diameter-expanding drilling tool according to 1) or 2), wherein the tip of the lower end tip is aligned with the tip of the lower end tip in the intermediate portion on substantially the same plane. 4) The protrusion provided on the dividing surface of the intermediate portion by the stopper means. A restraining recess having a predetermined width is provided in the center of the portion in the radial direction, and a stopper projection having a width shorter than the width of the restraining recess is provided in the left or right arc portion facing the restraining recess so as to be inserted into the restraining recess. The radial expansion tool according to any one of 1) to 3) above, wherein the diameter of the diameter reduction is set by the movement of the stopper projection in the radial direction being restrained by the restraining recess. 5) The head of the intermediate portion A water injection channel was formed from the water injection hole in the center to the fountain hole in the drilled hole at the bottom. Is provided at the top and bottom of the split surface, and water is jetted from the spray hole to face the gap between the split surface of the middle part and the mating surfaces of the left and right arc parts facing it. The diameter expansion drilling tool according to any one of the above 1) to 4), in which the left and right circular arc portions can be reliably rotated by spraying water to wash out slime or earth and sand in the voids to the outside of the cylindrical body.

  According to the present invention, the columnar portion below the head is vertically divided into three parts, that is, the intermediate portion and the left and right arc portions that are integrally manufactured with the head portion, and the left and right arc portions are the central axis of the columnar body above them. With a structure that allows the diameter to be expanded by pivotally attaching it with a more eccentric pivot pin, the opposing surfaces of the left and right arc portions and the intermediate portion are not separated in the radial direction by multiple dovetails, and rotate around the pivot pin. It is possible to expand and contract smoothly. By adopting this dovetail groove engagement structure, even if a strong rotating torque (resistance) from the ground acts on the circular arc portion, the rotating torque is distributed on the mating surface that makes full contact with the male and female long dovetail grooves. Against this, the deformation and damage of the arc portion is reduced, there is no high load load that deforms the pin to the pivot pin, the deformation and damage of the arc portion can be reduced, and the expansion and contraction of the arc portion can be done smoothly.

  In addition, the mating surface of the dovetail groove can contact the entire surface, producing a high resistance against the outward force, and the tapered inclined surface on the male side where the dovetail groove enters enters the dovetail groove on the female side. The remaining slime and earth and sand are pushed out from the open end of the dovetail groove at the outer diameter position of the convex portion, and the slime and earth and sand are discharged to the outside. Since the dovetail groove of the present invention is terminated at the outer diameter position of the cylindrical body, it is possible to reliably remove the earth and sand / slime in the dovetail groove space to the outside.

  The rotation direction of the diameter reduction of the present invention is rotation in the diameter expansion direction when the pivot pins of the left circular arc portion and the right circular arc portion are located on the rotation front side in the rotational direction. Further, when each pivot pin is located on the rear side in the rotational direction, the rotational direction is a reduced diameter. The diameter expansion state or the diameter reduction state is switched depending on the rotation direction of the diameter expansion drilling tool (columnar body) of the rotation device.

  In the invention in which the tips of the tips of the middle portion and the left and right arc portions in the expanded state of the present invention are substantially in the same plane, all the chips work uniformly during excavation in the expanded state, and are efficient in the expanded state of the cylindrical body. To drill.

  Further, in the middle of the water injection passage that communicates from the water injection hole in the head of the middle portion of the present invention to the water injection hole in the drilled portion, water is ejected into the gap between the left and right divided surfaces and the fitting surfaces of the left and right arc portions. In the invention having a structure in which a plurality of pouring holes are provided above and below, there is a space between the dividing surface of the intermediate portion divided into three and the facing surfaces (fitting surfaces) of the left and right arc portions facing the dividing surface. Slime and earth and sand can be washed out with a fountain from the pouring hole, the fitting surface is not blocked by slime and earth and sand, and the rotation of the expansion and contraction of the left and right circular arc parts is not obstructed. Also, it is possible to prevent clogging of the dovetail with slime and earth and sand, and to ensure that the dovetail can be fitted.

In this way, the left and right circular arc portions are simultaneously expanded in the forward rotation direction to perform drilling by expanding the diameter, and the reverse rotation direction reduces the diameter of the circular arc portion and becomes the drilling with the outer diameter of the cylindrical body. .
Rotating in the direction of diameter expansion, drilling with a large diameter, when finished and collecting the tool, reverse rotation is performed to reduce the diameter so that the tool can be easily withdrawn from the drilled hole. .

FIG. 1 is a left side view showing a diameter expansion drilling tool according to an embodiment of the present invention. FIG. 2 is an enlarged bottom view of the embodiment. FIG. 3 is a plan view of the same embodiment. FIG. 4 is a left side view showing the expanded diameter state of the embodiment. FIG. 5 is an enlarged sectional view taken along the line AA of FIG. FIG. 6 is an enlarged sectional view taken along line BB of FIG. FIG. 7 is a left side view showing an intermediate portion of the third division of the embodiment. FIG. 8 is an enlarged sectional view taken along the line CC of FIG. FIG. 9 is a rear view showing a fitted state by the dovetail groove of the embodiment. FIG. 10 is an enlarged rear view showing the left arc portion of the embodiment. FIG. 11 is an enlarged bottom view of the left arc portion of the embodiment. FIG. 12 is an enlarged front view showing the left arc portion of the embodiment. FIG. 13 is an explanatory view of the fitting of the middle portion and the left arc portion of the embodiment. FIG. 14 is an explanatory view of the fitting of the middle part and the right arc part of the embodiment. FIG. 15 is an enlarged cross-sectional view taken along the line AA of FIG. FIG. 16 is an enlarged sectional view taken along the line BB of FIG. FIG. 17 is an enlarged cross-sectional view taken along the line DD of FIG. FIG. 18 is an enlarged arrow view from the line CC of FIG. FIG. 19 is an enlarged front view showing components of the stopper protrusion of the embodiment.

As the stopper means for limiting the rotation angle of the present invention, as in the embodiment, a restraining recess is provided at the center of the convex portion of the intermediate portion, and a stopper convex portion to be inserted into the restraining recess is formed on the back surface (inner surface) of the left and right circular arc portions. Provided, a structure for restricting the diameter reduction and / or the diameter expansion, or a step portion between the fitting convex portions of the left and right circular arc portions is brought into contact with the peripheral portion of the starting point α-α of the convex portion of the intermediate portion to increase the widening angle. It can also be regulated.
The material of the diameter-expanding drilling tool of the present invention is one that has been subjected to precision processing by high-rigidity casting or pressing, and the tip is a cemented carbide tip. Further, it is preferable that the stopper projection of the present invention is manufactured as a separate body, fitted into the installation grooves of the left and right arc parts, and fixed by welding. Further, the diameter-expanding drilling tool can be used with a cylindrical body having an outer diameter of about 40 mm from a small diameter to a medium diameter and a diameter of about 1 m.

  Embodiments shown in FIGS. 1 to 19 will be described below with reference to the drawings. The diameter expanding drilling tool of the present embodiment is an example of a small diameter expanding drilling tool having the structure according to the second aspect of the invention. The left and right sides of this embodiment have a symmetrical structure.

(Description of Drawings of Examples)
FIG. 1 shows a left side view of the embodiment in a reduced diameter state, and FIG. 9 shows a rear view of the embodiment in a reduced diameter state. FIG. 4 shows a left side view of the expanded diameter state of the embodiment. FIG. 7 shows a left side view of the intermediate portion 1A of the embodiment, FIG. 10 shows a rear view of the left arc portion 1B of the embodiment, and FIG. 12 shows a front view of the left arc portion 1B of the embodiment. In addition, FIG. 13 is a rear view of the split surface 1A1 of the intermediate portion 1A and the left circular arc portion 1B pivotally attached to the divided surface 1A1, and a convex portion, a fitting convex portion, and a dovetail groove AR before pivotal attachment by the pivot pin 1A3. It shows the starting point α and the ending point β of the dovetail groove and the arrangement of the U-shaped dovetail groove AR. FIG. 14 shows the shape of both of them and the arrangement of the dovetail grooves AR in a diagram together with a right side dividing surface 1A2 of the intermediate portion 1A and a rear view of the right arc portion 1C of the embodiment.

  In the present embodiment, the engaging structure on the dividing surfaces 1A1 and 1A2 of the intermediate portion 1A, the left circular arc portion 1B and the right circular arc portion 1C is complicated. FIG. 7 shows the positions of the upper and lower three convex portions 1A15a, 1A15b, 1A15c, the restraining recess 1A5, and the pivot pins 1A3, 1A4 on the left split surface 1A1 of the intermediate portion 1A, and the starting point α of the U-shaped dovetail groove AR, The end point β is explained. The right divided surface 1A2 also has a structure similar to that of the left divided surface 1A1 and is symmetrical with FIG. 7, and the unevenness and the dovetail grooves AR, α, β are shown in the right diagram of FIG. The dividing surface 1A2 has three upper and lower convex portions 1A25a, 1A25b, and 1A25c, and each has a U-shaped dovetail groove AR having a starting point α and an ending point β, and a restraining recess 1A5. The convex portions 1A15a to 1A15c of the left-side division surface 1A1 and the U-shaped dovetail groove AR, their start points α and end points β, and the fitting convex portions of the back surface (back surface, inner surface) of the left arc portion 1B pivotally attached thereto. FIG. 13 shows the relationship between 1B1a and the dovetail AR, and the convex portions 1A25a to 1A25c of the right dividing surface 1A2 of the intermediate portion 1A and the U-shaped dovetail AR of the starting point α and the ending point β and the right arc portion pivotally attached thereto. The fitting convex portion 1C1a and the dovetail groove AR on the back surface of 1C are described in FIG.

(Explanation of reference numerals of the embodiment)
G is a diameter-expanding drilling tool of the present embodiment, 1 is a cylindrical body, 2 is its head, 2a is a neck portion of a gripping portion, and 2b is a diaper-shaped gripping portion that makes it easy to give a rotational torque to the cylindrical body 1. Is. 1A is an intermediate part obtained by dividing the cylinder 1 into three parts, 1B is one left circular arc part which is divided into three parts, 1C is one right circular arc part which is divided into three parts, and 3 is a cemented carbide attached to the lower end of the cylindrical body 1. Drilling part with a tip 3a attached, 1A1 is a split surface on the left side of the intermediate portion 1A, 1A2 is a split surface on the right side of the intermediate portion 1A, 1A3 is a pivot pin of the left circular arc portion 1B, 1A4 is a right circular arc It is a pivot pin of the portion 1C (see FIGS. 1, 2, 3, 4, 5, 6, 9, 10, 12, 13, and 14).

  7, 9, 10, 12, 13, and 14, 1A15a, 1A15b, and 1A15c are convex portions provided on the division surface 1A1 of the intermediate portion 1A, and 1A25a, 1A25b, and 1A25c are convex portions provided on the division surface 1A2 of the intermediate portion 1A. It is a department. 1A15au is the outer peripheral upper edge of the convex portion 1A15a, 1A15as is the outer peripheral lower edge of the convex portion 1A15a, 1A15bu is the outer peripheral upper edge of the convex portion 1A15b, 1A15bs is the outer peripheral lower edge of the convex portion 1A15b, 1A15cu is the outer peripheral upper edge of the convex portion 1A15c, 1A15cs is an outer peripheral lower edge of the convex portion 1A15c. Similarly, 1A25au is the outer peripheral upper edge of the convex portion 1A25a, 1A25as is the outer peripheral lower edge of the convex portion 1A25a, 1A25bu is the outer peripheral upper edge of the convex portion 1A25b, 1A25bs is the outer peripheral lower edge of the convex portion 1A25b, and 1A25cu is the convex portion 1A25c. The upper peripheral edge 1A25cs is the lower peripheral edge of the convex portion 1A25c. 4A is a thick portion above the intermediate portion 1A, 5A is a thick portion below the intermediate portion 1A, 4B is an upper step portion of the left circular arc portion 1B, and 5B is a middle portion 1A below the left circular arc portion 1B. A dovetail groove that engages with the lower thick portion 5A, 4C is an upper step portion of the right circular arc portion 1C, and 5C is a lower dovetail groove of the right circular arc portion 1C.

Further, 1B1 is a back surface (inner surface) of the left circular arc portion 1B, 1C1 is a rear surface (inner surface) of the right circular arc portion 1C, 1B1a is an arm-shaped fitting convex portion of a rear surface 1B1 of the left circular arc portion 1B, and 1C1a is a right circular arc portion 1C. Arm-shaped fitting projections on the back surface 1C1, 1B1b are outer projections above the back surface 1B1 of the left arc portion 1B, 1C1b are outer projections above the back surface 1C1 of the right arc portion 1C, and 1B1c is the back surface of the left arc portion 1B. 1B1 is a lower outer convex portion, 1C1c is a lower outer convex portion of the back surface 1C1 of the right arc portion 1C, AR is a convex portion 1A15a to 1A25c of the intermediate portion 1A, and arm-shaped fitting convex portions 1B1a, 1C1a and the outer convex portion. It is a dovetail groove at the contact point with the portions 1B1c and 1C1c.
Further, 1A5 is a restraining recess provided at the center of the upper surfaces of the convex portions 1A15a to 1A25c projecting on the split surfaces 1A1 and 1A2, and 1D5 is the installation groove of the back surfaces 1B1 and 1C1 (inner surface) of the left and right arc portions 1B and 1C. It is a stopper protrusion that is fitted into the fitting hole 1E1 of 1E, is welded to the installation groove, and is inserted into the restraining recess 1A5. The width of the stopper convex portion is about 6 mm, and the width of the restraining recess 1A5 into which the stopper convex portion is inserted becomes larger, and the angle of the diameter expansion is limited to about 5 ° by rotating the left and right circular arc portions 1B and 1C. ing.

Further, as shown in FIGS. 1, 7, 8, 13, and 14, there is a water injection port W _{1 at} the head of the columnar body 1 of the diameter expansion drilling tool G of the embodiment, and the tip of the intermediate portion 1A (drilling portion). The water injection path W ₃ is provided up to the fountain hole W ₄ provided in 3). The fountain from the fountain hole W ₄ is for discharging the ground slime / sand and cooling the chips. Then, _three small pouring holes W ₂ communicating with the water injection passage W ₃ are provided on each of the front and back divided surfaces 1A1 and 1A2 of the water injection passage W _3, and the water of the water injection passage W ₃ is provided on the division surface 1A1. , 1A2 sprays water toward the fitting surface (rear surface 1B1) of the left arc portion 1B and the fitting surface (rear surface 1C1) of the right arc portion 1C, and split surfaces 1A1, 1A2 in the middle portion and rear surface 1B1 of the left and right arc portions. , 1C1 is filled with a fountain flow and the slime, earth and sand, etc. in these gaps are discharged to the outside of the cylindrical body 1 so that the left and right arc portions 1B, 1C can be smoothly rotated (expanded / contracted). There is.

(Explanation of the operation of the embodiment)
In this embodiment, as shown in FIGS. 1, 4, 7, 13, and 14, the left circular arc portion 1B is rotatable around the pivot pin 1A3. The right circular arc portion 1C having the same structure is also rotatable around its pivot pin 1A4. Both are symmetrical in shape and size. Moreover, the upper and lower outer peripheral edge upper edges and the lower edges 1A15au to 1A25cs of the protruding portions 1A15a to 1A25c projecting from the left and right dividing surfaces 1A1 and 1A2 of the intermediate portion 1A are circles around the pivot pins 1A3 and 1A4. It is on an arc line. Further, the upper and lower peripheral edges of the arm-shaped fitting convex portions 1B1a, 1C1a and the outer convex portions 1B1c, 1C1c of the left and right circular arc portions 1B, 1C are also on the circular arc line around each pivot pin 1A3, 1A4. And the step fitting portion 6 of the thick portion 4A above the uppermost convex portions 1A15a, 1A25a and the lower intermediate portion of the lowermost convex portions 1A15c, 1A25c that can be seen on the left and right divided surfaces of the intermediate portion 1A. The dovetail groove fitting portion 7 of the thick portion 5A is also on the arc line around the pivot pins 1A3 and 1A4.

  Therefore, as shown in FIGS. 4, 9, 10, and 13, when the left circular arc portion 1B is rotated around the pivot pin 1A3, the two arm-shaped fitting projections 1B1a are located on the split surface 1A1 of the intermediate portion 1A. The three protrusions 1A15a, 1A15b, and 1A15c are inserted into the valley space between the upper and lower peripheral edges. Moreover, the contact between the peripheral edges is the dovetail groove AR in both cases. The outer convex portion 1B1c below the rear surface 1B1 of the left arc portion 1B forms the dovetail groove fitting portion 7 with the thick portion 5A of the intermediate portion 1A. In addition, the dovetail grooves AR of the fitting convex portion 1B1a and the outer convex portion 1B1c are in contact with each other so that they are on the lower side.

  Therefore, the fitting convex portion 1B1a of the left circular arc portion 1B is restrained by the convex portions 1A15a to 1A15c of the dividing surface 1A1 of the intermediate portion 1A by the dovetail groove AR, and the fitting convex portion 1B1a has three U-shaped dovetail grooves AR. Since it is supported on the entire circumference of and in the entire contact surface, it is possible to counter a high outward force (peeling force outward in the radial direction). Therefore, it has high connection strength.

  Similarly, as shown in FIG. 14, when the right circular arc portion 1C is rotated around the pivot pin 1A4, the two arm-shaped fitting protrusions 1C1a also form three protrusions on the split surface 1A2 of the intermediate portion 1A. The parts 1A25a, 1A25b, 1A25c are inserted into the valley spaces between the peripheral edges facing each other in the vertical direction. Moreover, the contact between the peripheral edges is the upper and lower three U-shaped dovetail grooves AR. Also, the outer convex portion 1C1c below the back surface 1C1 of the right arc portion 1C forms a dovetail groove fitting portion 7 with the thick portion 5A below the dividing surface 1A2 of the intermediate portion 1A. Moreover, the fitting projections 1C1a and the outer projections 1C1c are contacted so that the dovetail grooves are on the lower side.

  Therefore, the right circular arc portion 1C is restrained by the three dovetail grooves AR by the convex portions 1A25a to 1A25c of the dividing surface 1A2 at the intermediate portion, so that a high outward force can be opposed. Therefore, it has high connection strength.

Moreover, the fitting convex portions 1B1a, 1C1a and the outer convex portions 1B1c, 1C1c become the dovetail groove AR, and the valley space between the convex portions 1A15a to 1A25c of the dividing surfaces 1A1, 1A2 and the inclined surface of the dovetail groove AR of the thick portion 5A. Since it enters, the slime / sand that has entered the dovetail groove AR can be pushed in easily and surely, and the slime / sand that has entered the dovetail groove AR is discharged from the outer diameter position to the outside of the cylindrical body 1.
As a result, the dovetail groove AR can be reliably inserted without being clogged with earth and sand. In addition, the dovetail groove AR also obtains a high counter force even when it comes into full contact.
Furthermore, the β-α-α-β U-shaped dovetail groove AR is located at three upper and lower positions, and the length of the engaging force generated by the U-shaped dovetail AR is long and dispersed vertically. Even if the reaction force from the inside exerts a strong force in the radial direction and a strong rotational torque by expanding the diameter, the left and right circular arc portions 1B and 1C and the pivot pins 1A3 and 1A4 are sufficiently deformed and damaged. I reduced it.

The diameter of the rotation is expanded from 0 ° (reduced diameter) to + 5 ° by restricting the movement of the stopper protrusions 1D5 on the left and right arc portions 1B and 1C by the restraining recess 1A5 provided on the protrusion of the intermediate portion 1A. It stops at the angle of (expanded state). The rotation angle of 5 ° is the maximum expansion angle. The expansion of the diameter can be regulated by engagement between the α-α peripheral edge of the convex portion of the intermediate portion 1A and the stepped portion between the fitting convex portions.
Next, when the rotation direction is reversed, the reaction force from the ground acts in a direction of reducing the diameter. The columnar body 1 returns to the reduced diameter state in which the rotation angle is 0 °.
When the diameter is expanded, the hole is drilled in the expanded state, the tip of the tip 3a is on the same surface, and the tip 3a works uniformly to enable the drilling, and the excavation in the expanded state is also efficient. There is.

As described above, in the present embodiment, even if the diameter is increased, the dovetail groove firmly connects the left and right arc-shaped components to the intermediate components against the resistance and rotational torque from the ground, and the deformation and damage of them can be reduced. .
Moreover, the fountain flow from the pouring hole W ₂ flushes out the slime / sand in the gap between the split surfaces 1A1, 1A2 of the intermediate portion 1A and the fitting surfaces (rear surfaces 1B1, 1C1) of the left and right arc portions 1B, 1C. The expansion and contraction of the left and right arc portions 1B and 1C are ensured.

  Although the embodiment of the present invention is a diameter expanding tool for underground excavation having a small diameter, it is possible to make diameter expanding excavation having a considerably large diameter by making the diameter of the cylindrical body considerably large. It can also be effectively used for drilling the widening foundation of underground anchors.

G Expanding drilling tool 1 Cylindrical body 2 Head 2a Neck 2b Gripping 1A Intermediate part 1B Left arc part 1C Right arc part 3 Drilling part 3a Tip 1A1 Dividing surface on the left side of the intermediate part 1A2 Dividing surface on the right side of the intermediate part 1A3 Pivot pin for left circular arc portion 1A4 Pivot pin for right circular arc portion 1A15a, 1A15b, 1A15c Convex portion 1A25a, 1A25b, 1A25c provided on left division surface 1A1 of intermediate portion 1A On right division surface 1A2 of intermediate portion 1A Provided convex portion 1A15au Outer peripheral upper edge of uppermost convex portion 1A15a 1A15as Outer peripheral lower edge of uppermost convex portion 1A15a 1A15bu Outer peripheral upper edge of convex portion 1A15b 1A15bs Outer peripheral lower edge of convex portion 1A15b 1A15cu Lowermost convex portion 1A15c Outer peripheral upper edge 1A15cs outermost lower edge 1A25au uppermost of the lowermost convex portion 1A15c Outer peripheral upper edge of the convex portion 1A25a 1A25as outer peripheral lower edge of the uppermost convex portion 1A25a 1A25bu outer peripheral upper edge of the convex portion 1A25b 1A25bs outer peripheral lower edge of the convex portion 1A25b 1A25cu outer peripheral upper edge of the lowermost convex portion 1A25c 1A25cs bottom Outer peripheral edge of the convex portion 1A25c on the side 1B1 Back surface (inner surface) of the left circular arc portion
1C1 Right circular arc back surface (inner surface)
1B1a Arm-shaped fitting convex portion of back surface 1B1 of left circular arc portion 1C1a Arm-shaped fitting convex portion of rear surface 1C1 of right circular arc portion 1B1b Outer convex portion above rear surface of left circular arc portion 1C1b Upper outside of rear surface of right circular arc portion Convex portion 1B1c Outer convex portion below the back surface 1B1 of the left arc portion 1C1c Outer convex portion below the rear surface 1C1 of the right arc portion AR Dovetail groove α Dowel groove start point β Dovetail groove end point 1A5 Restraining recess 1D5 Stopper protrusion 1E Installation groove 1E1 Fitting hole W ₁ Water injection port W ₂ Water injection hole W ₃ Water injection channel W ₄ Fountain hole 4A Thick part 5A above the middle part 5A Thick part below the middle part 4B Upper step part 5B on the left arc part 5B Lower dovetail groove of left arc part 4C Upper step part of right arc part 5C Lower dovetail groove of right arc part 6 Step part fitting part 7 Dovetail groove fitting part

Claims (5)

The cylinder has a head above which a pressing force and a rotational torque can be loaded, and the bottom of the cylinder has a hole with a plurality of chips attached downward, and the direction of rotation of the cylinder. According to, the outer diameter of a part of the hole-drilling part is expanded / contracted, and it is a diameter-expanding drilling tool that enables underground excavation with a wide width underground by rotating in the direction of expanding the hole-drilling part,
The shape of the lower part integrally manufactured with the head part by dividing the lower part of the cylinder part including the drilled portion below the head part of the cylinder part into three parts on the vertical surface in the axial direction of the cylinder part. Is a substantially plate-shaped intermediate portion, a left circular arc portion on the outside thereof, and a right circular arc portion on the opposite side of the outer portion thereof are formed into three parts, and the intermediate portion, the left circular arc portion and the right circular portion are formed. A plurality of chips are projected downward at each of the lower ends of the circular arc portions, and the left circular arc portion and the right circular arc portion are positioned above the dividing planes on both the left and right below the head of the intermediate portion, and the axis of the cylindrical body is The left circular arc portion and the right circular arc portion, which are rotatably pivoted by pivot pins that are eccentric to each other in opposite directions from the core line and are rotatable about the pivot pins, face each other. The dividing surface of the middle part is a pair of upper and lower circular arcs centered on the pivot pin. Along the inner circumference and at the position of the outer diameter of the cylindrical body, and are arranged in a U-shape connecting the starting ends in the center of the dividing surface of the arc line of the set, and a plurality of sets are provided in a state of being vertically separated. It is connected slidably along the dividing surface by the unevenness of the dovetail groove, and the rotation around the pivot pin of the left and right circular arc parts is within a predetermined maximum expansion angle from 0 ° without expansion. A diameter-expansion drilling tool, characterized in that stopper means for restricting a rotation angle to be restricted is provided between the left and right circular arc portions and the intermediate portion.   A plurality of convex portions, each having a thin thickness and a top surface parallel to the dividing surface, are provided on the left and right dividing surfaces of the intermediate portion so as to be separated from each other in the vertical direction of the dividing surface, and the convex portions face the dividing surface. The left or right circular arc part has upper and lower peripheral edges along an arc line centered on the eccentric pivot pin, and is arranged close to the right and left regions opposite to the left and right regions where the pivot pin is located, and in the middle. On the back surfaces of the left and right circular arc portions facing the divided surface of the part, an arm-like member is fitted into the valley space between the convex portions which are separated from each other in the middle part, and the tip extends to the outer diameter position of the middle part in a reduced diameter state. A fitting convex portion is provided, and between the outer peripheral upper edge of the convex portion of the uppermost intermediate portion and the thick portion of the intermediate portion above the uppermost convex portion, and the convex portion of the lowermost intermediate portion. Between the lower edge of the outer periphery and the thick portion of the intermediate portion below the lowermost convex portion The upper and lower outer peripheral edges of the outer peripheral edge portion of the outer convex portion and the uppermost lower convex portion have upper and lower outer convex portions, respectively, which are inserted and extend to the outer diameter position of the intermediate component in a reduced diameter state. Is a structure in which they are vertically engaged with each other, while the fitting convex portion and the peripheral edge of the convex portion of the intermediate portion are in contact with each other by a dovetail groove structure, and the tapered inclined surface of the peripheral edge of the fitting convex portion is a dovetail groove. The diameter expanding drilling tool according to claim 1, wherein the diameter expanding drilling tool is located on the lower side.   The expansion according to claim 1 or 2, wherein the left and right arc portions are rotated around a pivot pin so that the tip of the lower end tip in the expanded state is flush with the tip of the lower end tip of the intermediate portion. Diameter drilling tool.   The stopper means provides a restraining recess of a predetermined width in the radial direction at the center of the convex portion provided on the dividing surface of the intermediate portion, and a width shorter than the width of the restraining recess at the left or right arc portion facing the restraining recess. 4. The stopper protrusion is provided so as to be inserted into the restraining recess, and the radial reduction of the stopper protrusion is restrained at the restraining recess to set the angle of the diameter reduction. 5. Expanding drilling tool.   A water injection channel formed from a water injection port at the center of the head of the middle part to a water hole at the drilled hole at the lower end is provided, and a plurality of water injection channels for spraying the water injection channel at the position of the dividing surface are provided vertically. Water is jetted from the outlet to spray water toward the gap between the dividing surface of the intermediate portion and the fitting surfaces of the left and right arc portions facing it so that the slime or sand in the void is washed out to the outside of the cylinder. The diameter-expanding drilling tool according to any one of claims 1 to 4, wherein the left and right circular arc portions can be reliably rotated.

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