JP7687615B2 - Drilling and mixing machine - Google Patents

Description

The present invention relates to a drilling mixer for excavating ground.

For example, Patent Document 1 discloses a drilling and mixing device used to construct soil cement pillars in the ground. The drilling and mixing device is equipped with a rod with a drilling bit connected to its tip, and a hole is drilled in the ground with the drilling bit by rotating the rod around its axis with a rotating means and applying vertical vibrations to the rod with a vibration generating means. In addition, while drilling a hole in the ground, cement milk is ejected from the tip of the drilling bit to construct a soil cement pillar in the drilled hole.

In the drilling and mixing device of Patent Document 1 described above, the rod is configured by connecting multiple steel pipes in series with a screw-type joint structure. Therefore, the operation of the rotating means for rotating the rod around its axis is controlled so that it rotates only in the same direction as the tightening direction of the screw-type joint structure.

JP 2011-252349 A

According to the drilling and mixing device of Patent Document 1, the drilling bit rotates and vibrates vertically via the rod, so that even if a hard layer is present in the ground, it is possible to efficiently excavate and build a soil cement column. However, as described above, the rotation direction of the rod equipped with the drilling bit is limited to one direction around the axis. For this reason, for example, if there is a gravel layer or a backfill layer made of compacted slag in the ground, and the drilling bit spins freely or bites into these layers during excavation, making it impossible to proceed, it is not possible to take measures such as temporarily reversing the rotation direction of the rod.

As a result, it was necessary to first raise the drilling bit together with the rod, then rotate it appropriately to move the position of the drilling bit, then lower it and allow it to hit the bottom of the excavation before resuming underground drilling, which made the construction operation cumbersome.

In addition, when vertical vibrations are applied to the rod via the vibration generating means, the screw-type joint structure may loosen and cause rattling. If such rattling occurs, the vertical vibrations applied to the rod may not be transmitted smoothly to the drilling bit, and it may not be possible to improve the drilling efficiency by applying vibrations.

The joint structure used to connect the rods may be not only the screw-type joint structure of Patent Document 1, but also, for example, a flange-type joint structure as shown in Figure 10(a) or a hexagonal joint pin-type joint structure as shown in Figure 10(b).

In the flange-type joint structure 70 in FIG. 10(a), flanges 71, 72 provided at the ends of steel pipes 31a, 31b arranged above and below are butted together and fastened with bolts 73. Such flange-type joint structure 70 transmits the vertical vibration and rotational force around the steel pipe axis applied to the upper steel pipe 31b to the lower steel pipe 31b via the bolts 73. For this reason, if a hard layer exists in the ground, the number of bolts 73 must be increased to deal with this, and the connection work takes a lot of time. In addition, if the bolt joint is repeatedly subjected to the above-mentioned vertical vibration and rotational force around the steel pipe axis, it is likely to loosen, and in such cases, the work may become complicated, such as interrupting construction and re-tightening the bolts.

In the hexagonal joint pin type joint structure 80 in FIG. 10(b), a square tube portion 821 with a hexagonal cross section provided in a male joint 82 is fitted into a square hole portion 831 provided in a female joint 83, and then a pair of connection pins 81 are passed through them. The pair of connection pins 81 are offset in the height direction on both sides of the axis of the male joint 82 and the female joint 83, and pass through in a direction perpendicular to the axis. For this reason, the square hole portion 831 is provided with a through hole 832 through which the connection pin 81 passes, and the square tube portion 821 is provided with a notch 822 through which the connection pin 81 passes.

In this type of hexagonal joint pin type joint structure 80, if there is no play between the square hole portion 831 and the square tube portion 821 in the fitted state and the connection pin 81, the connection pin 81 cannot be inserted. This creates a risk that even if vertical vibration is applied to the upper steel pipe 31b, this vibration cannot be transmitted to the lower steel pipe 31a due to the play. Instead of a structure that provides play, it is possible to, for example, provide a taper on the connection pin 81 to give it a wedge shape, but this would require complicated processing and would be expensive to manufacture.

The present invention has been made in consideration of these problems, and its main objective is to provide a drilling mixer that can transmit vertical vibrations applied to a rod and forward and reverse rotational forces around the rod axis to a drilling head attached to the tip of the rod.

In order to achieve this objective, the drilling mixer of the present invention is a drilling mixer that applies rotational force and vertical vibration to a rod connected to a drilling head at its tip, thereby drilling the ground with the drilling head, and the rod has a rod body and a joint structure that connects the rod body in the axial direction, and the joint structure is composed of a convex joint with a flange on its outer circumferential surface and a square tube portion, a concave joint with a flange on its outer circumferential surface and a square hole portion that fits into the square tube portion, and a pressing member that butts and clamps the flange of the convex joint and the flange of the concave joint, and is characterized in that the cross section where the flange of the convex joint and the flange of the concave joint are butted together forms a taper that tapers toward the outer circumferential edge.

According to the drilling mixer of the present invention described above, a rod with a drilling head connected to its tip is configured with a joint structure that connects multiple rod bodies, and the convex joint that constitutes the joint structure has a square tube portion, and the concave joint has a square hole portion into which the square tube portion fits. As a result, the forward and reverse rotational forces applied to one of the rod bodies connected by the joint structure can be transmitted to the other via the square hole portion of the concave joint and the square tube portion of the convex joint that constitute the joint structure.

In addition, the cross section of the flange of the convex joint and the flange of the concave joint held by the holding member, when butted together, tapers toward the outer periphery. Therefore, if a fitting groove that fits with this taper is provided in the holding member, the flange of the convex joint and the flange of the concave joint will fit into the fitting groove in a wedge shape, increasing the clamping force in the vertical direction (the axial direction of the convex joint and the concave joint), and the convex joint and the concave joint can be firmly held in place. As a result, vertical vibrations applied to one of the rod bodies connected by the joint structure can be transmitted to the other via the holding member that constitutes the joint structure.

Therefore, it is possible to apply the vertical vibration and forward and reverse rotational forces around the rod axis, which are applied to the base end of a rod made of multiple rod bodies connected by a joint structure, to the excavation head attached to the tip of the rod. In this way, if there is a layer of compacted gravel in the ground, for example, if the excavation head spins freely or bites into the layer and becomes unable to excavate, measures can be taken such as rotating the excavation head in the reverse direction via the rod. As a result, even if there is a layer of gravel in the ground, excavation work can be continued without complicated operations, making it possible to significantly improve the workability of excavating the ground.

According to the present invention, by connecting multiple rod bodies constituting a rod with a drilling head at its tip using a joint structure that uses a convex joint with a square tube portion and a concave joint with a square hole portion into which the square tube portion fits, and a clamping member that holds them together, it becomes possible to smoothly transmit the vertical vibrations applied to the rod and the forward and reverse rotational forces around the rod axis to the drilling head at the tip of the rod.

FIG. 1 is a diagram showing a drilling mixer according to an embodiment of the present invention. FIG. 2 is a diagram showing a rod body according to an embodiment of the present invention. 4A to 4C are diagrams showing an angular tube portion of a convex joint and an angular hole portion of a concave joint in an embodiment of the present invention. 1A to 1C are diagrams showing a procedure for forming a joint structure in an embodiment of the present invention (part 1). 11A to 11C are diagrams showing a procedure for forming a joint structure in an embodiment of the present invention (part 2). 5A to 5C are diagrams showing details of a joint structure in an embodiment of the present invention. 1A to 1C are diagrams showing a procedure for extending a rod by adding a rod body in an embodiment of the present invention (part 1). 13A to 13C are diagrams showing a procedure for extending a rod by adding a rod body in an embodiment of the present invention (part 2). FIG. 2 is a diagram showing a state in which a gravel layer is excavated by a drilling mixer in an embodiment of the present invention. FIG. 1 is a diagram showing a joint structure (flange type and hexagonal joint pin type) of the prior art.

The details of the hole-boring mixer of the present invention will be described with reference to Figures 1 to 9. In this embodiment, an example of constructing an underground hole is given, but the hole-boring mixer can also be used to build soil cement columns.

<<Drilling and mixing machine>>
As shown in Figure 1, a drilling mixer 1 used when excavating a target ground comprises a crawler running body 2, an upper rotating body 3 mounted on the crawler running body 2, and a leader 4 supported so as to be freely raised and lowered.

When in an upright position, the leader 4 has a guide 41 on its front side that extends in the vertical direction, and is equipped with a lifting body 42 that rises and falls along the guide 41. Two extension devices 43, 44 are provided on the rear side, and the leader 4 and the upper rotating body 3 are connected via these. The leader 4 can be freely moved between upright and down positions by the extension and retraction movements of the extension devices 43, 44.

The leader 4 is also provided with a chuck mechanism 45 at its lower end. Any device may be used as the chuck mechanism 45 as long as it has a configuration capable of gripping the rod 20 and drilling head 10 described below. The chuck mechanism 45 does not necessarily have to be attached to the leader 4, and may be a device separate from the drilling mixer 1.

The drilling mixer 1 further includes a vibration exciter 9 mounted on the lifting body 42, a rotation device 8 connected to the lower part of the vibration exciter 9, a drive shaft 7 that passes through the rotation device 8 and has a base end connected to the vibration exciter 9, a rod 20 connected to the tip of the drive shaft 7, and a drilling head 10 connected to the tip of the rod 20.

The vibration device 9 is a device that generates a vibration force in the vertical direction by rotating an eccentric weight, and moves along the guide 41 via the lifting body 42, so that when the leader 4 is raised, it moves in the lifting direction. Note that any device that can generate a vibration force that can transmit vibrations including a vertical component to the drive shaft 7 may be used as the vibration device 9.

The rotation device 8 is installed on the lifting body 42 and connected to the vibration device 9, and moves along the leader 4 in an upright position together with the vibration device 9. Inside, a drive shaft locking part (not shown) is provided, which locks the circumferential surface of the drive shaft 7 and applies a rotational force in the forward or reverse direction around the shaft.

The drive shaft 7 is made of a single pipe with a hollow section, and a swivel joint 6 is attached to the middle of it, to which a fluid supply pipe 5, such as a cement milk supply pipe or a stabilizing liquid supply pipe, is connected. This makes it possible to supply fluids such as cement milk or stabilizing liquid S supplied from the fluid supply pipe 5 to the rod 20 from the swivel joint 6 via the drive shaft 7. Figure 1 shows an example of supplying stabilizing liquid S.

The rod 20 is composed of a rod body 30 and a joint structure 50 that connects the rod body 30 in the axial direction. Its base end is connected to the drive shaft 7 via the joint structure 50, and its tip end is connected to the drilling head 10 via the joint structure 50. Details of the rod body 30 and the joint structure 50 will be described later.

The drilling head 10 is connected to a rod 20 and comprises a shaft 11 made of a single tube with a hollow section, a drilling blade body 13 attached so as to extend laterally near the tip of the shaft 11, and a bit 14 attached to the drilling blade body 13. In addition, a number of stirring blades 12 extending radially are installed on the shaft 11 at a position spaced upward from the drilling blade body 13, and a tip bit 15 and a fluid discharge port 16 are provided at the tip of the shaft 11.

The bit 14 and the tip bit 15 have a shape that allows them to excavate the ground whether the drilling head 10 rotates in the forward or reverse direction around the rod axis. The fluid outlet 16 also discharges the fluid supplied to the shaft 11 from the fluid supply pipe 5 via the swivel joint 6, the drive shaft 7, and the rod 20 toward the ground. In this embodiment, since an underground hole H is being excavated, the fluid discharged from the fluid supply pipe 5 is the stabilizing liquid S, but if cement milk is used as the fluid, it is also possible to build a soil cement column instead of the underground hole H.

The mixing blades 12 provided on the drilling head 10 are used when constructing a soil cement column as described above, in order to excavate the ground while discharging cement milk from the fluid discharge port 16 and mixing it, or when constructing an underground hole H and then supplying a cement-based solidification material to the underground hole H and mixing it with the stabilizing liquid.

<<Rod Details>>
In the drilling mixer 1 having the above-mentioned configuration, the rod 20 has a configuration capable of transmitting the vertical vibration applied from the vibration excitation device 9 via the drive shaft 7 and the forward and reverse rotations around the rod axis applied from the rotation device 8 to the drilling head 10. Details of the rod body 30 and the joint structure 50 constituting the rod 20 will be described below. The joint structure 50 is also used to connect the drive shaft 7 and the drilling head 10 to the rod 20, so these will also be described.

<<Rod body>>
As shown in FIG. 2, the rod body 30 comprises a tube 31 having a convex joint 32 and a concave joint 33 at both ends thereof.

The pipe material 31 is made of a single pipe similar to the drive shaft 7 and the shaft portion 11 of the drilling head 10 described above, and has a hollow portion 311 through which the fluid supplied from the fluid supply pipe 5 flows. A convex joint 32 is connected to one end, and a concave joint 33 is connected to the other end. Figure 2 shows an example of the pipe material 31 standing upright with the convex joint 32 on the upper side.

The convex joint 32 is made of a tube with a hollow section 321 that communicates with the hollow section 311 of the pipe material 31, and the base end side is formed into a cylindrical section 322 whose cross section is the same size and external shape as the pipe material 31, and is fixed to the pipe material 31 by a fastening means such as welding. On the other hand, the tip side is formed with a smaller cross section than the pipe material 31, and is formed into a square tube section 323 formed into a hexagonal doughnut shape as shown in Figure 3 (a).

A convex flange 324 is provided near the boundary between the cylindrical portion 322 on the base end side and the angular tube portion 323 on the tip end side. The convex flange 324 is formed to protrude from the outer circumferential surface of the cylindrical portion 322, and is formed in a truncated cone shape with the angular tube portion 323 side as the bottom surface and the cylindrical portion 322 side as the side surface. As shown in FIG. 6, the angular tube portion 323 side forms an opposing surface 324a with the concave flange 334 described later, and the cylindrical portion 322 side forms an abutment surface 324b with the pressing member 40 described later.

As shown in FIG. 2, the concave joint 33 is formed into a storage tube portion 332 whose cross section is the same size and external shape as the pipe material 31 over its entire length, and a hollow portion 331 is provided on the base end side that communicates with the hollow portion 311 of the pipe material 31. On the other hand, a square hole portion 333 that fits into the square tube portion 323 of the convex joint 32 is formed on the tip side, and the square hole portion 333 and the hollow portion 331 communicate with each other. The inner cross section of the square hole portion 333 is formed into a hexagon of the same size as the outer circumferential surface of the square tube portion 323, as shown in FIG. 3(b).

A concave flange 334 is provided at the tip of the storage tube portion 332. The concave flange 334 is formed to protrude from the outer circumferential surface of the storage tube portion 332, and is formed in a truncated cone shape with the tip side as the bottom surface and the pipe material 31 side as the side surface. As shown in FIG. 6, the tip side forms an opposing surface 334a with the above-mentioned convex flange 324, and the pipe material 31 side forms an abutment surface 334b with the pressing member 40 described later.

<<Joint structure 50>>
As shown in Figure 1, multiple rod bodies 30 having the above-mentioned configuration are arranged in parallel in the axial direction, and a joint structure 50 consisting of a convex joint 32 and a concave joint 33 provided on the rod body 30 and a pressing member 40 is formed between adjacent rod bodies 30 to form a rod 20.

That is, as shown in Figures 4(a) and (b), the square tube portion 323 constituting the convex joint 32 of the lower rod body 30a is inserted and fitted into the square hole portion 333 constituting the concave joint 33 of the upper rod body 30b, and the opposing surface 324a of the convex flange 324 and the opposing surface 334a of the concave flange 334 are abutted against each other. This makes it possible to transmit the rotational forces in the forward and reverse directions applied to the upper rod body 30b to the lower rod body 30a via the square hole portion 333 of the concave joint 33 and the square tube portion 323 of the convex joint 32.

At this time, a rod packing 60 is interposed between the tip of the square tube portion 323 of the convex joint 32 and the square hole portion 333 of the concave joint 33. The rod packing 60 is formed in a ring shape with a hole in the center so as to maintain communication between the hollow portions 321, 331 of the convex joint 32 and the concave joint 33.

In this way, the convex flange 324 and the concave flange 334, whose opposing surfaces 324a and 334a are butted against each other, are clamped by the pressing member 40 as shown in Figures 5(a) and (b). This allows the vertical vibration applied to the upper rod body 30b to be transmitted to the lower rod body 30a via the pressing member 40.

<Pressing member 40>
As shown in FIGS. 5(a) and 5(b), the pressing member 40 constituting the joint structure 50 as described above includes half-split members 401 and 402 and a fastener 403, and the fastener 403 includes a bolt 403a and a nut 403b.

As shown in FIG. 5(a), the half-split members 401 and 402 are formed by splitting a ring-shaped member of a size capable of surrounding the convex flange 324 of the convex joint 32 and the concave flange 334 of the concave joint 33, and ears 401b protruding in the radial direction are provided at both circumferential ends of the half-split member 401. These ears 401b are formed with bolt holes through which the bolts 403a pass. Similarly, ears 402b are provided at both circumferential ends of the half-split member 402, and bolt holes through which the bolts 403a pass are formed.

The half-split member 401 also has a circumferentially continuous mating groove 401a formed on its inner peripheral surface. Its cross-sectional shape is formed to fit with the convex flange 324 and the concave flange 334 when they are inserted with their opposing surfaces 324a, 334a butted together, as shown in FIG. 6. The cross-section of the convex flange 324 and the concave flange 334 butted together forms a taper that narrows toward the outer periphery, so the mating groove 401a is formed as a substantially V-shaped tapered groove that can fit with this taper. The half-split member 402 also has a circumferentially continuous mating groove 402a, and a substantially V-shaped tapered groove similar to the mating groove 401a is formed.

The procedure for mounting the pressing member 40 having the above configuration is as follows. As shown in FIG. 5(a), the half-split members 401 and 402 are arranged so as to surround the convex flange 324 and the concave flange 334 that are in a butted state, and are inserted and fitted into the fitting grooves 401a and 402a. As a result, the ears 401b and 402b of the half-split members 401 and 402 face each other, and as shown in FIG. 5(b), the bolt 403a is inserted through the bolt hole formed in the ears 401b and 402b, and the nut 403b is screwed and tightened.

As shown in FIG. 6, as the half-split members 401, 402 gradually approach each other, the convex flange 324 and the concave flange 334 enter the fitting grooves 401a, 402a in a wedge-like shape. At this time, both fitting grooves 401a, 402a have a groove depth D that ensures that the outer peripheral end faces of the convex flange 324 and the concave flange 334 do not abut against the groove bottom. As a result, the convex flange 324 and the concave flange 334 fully penetrate into the fitting grooves 401a, 402a, increasing the clamping force in the vertical direction (the axial direction of the convex joint 32 and the concave joint 33), and the convex joint 32 and the concave joint 33 can be firmly clamped.

Therefore, even if vertical vibrations are transmitted from the concave joint 33 side, it is possible to transmit the vertical vibrations to the convex joint 32 side via the pressing member 40 without rattling. The clamping effect of the pressing member 40 on the above-mentioned convex flange 324 and concave flange 334 is preferably achieved by setting the taper angle θ of the cross section where the convex flange 324 and concave flange 334 are butted to approximately 10 to 60°, and more preferably approximately 26°.

The holding member 40 may be provided with an eyebolt E, as shown in FIG. 6, for example. In this way, when attaching or detaching the holding member 40, the eyebolt E can be used to suspend the holding member 40 with a wire, thereby preventing it from falling.

As shown in Figure 1, the above joint structure 50 is also used to connect the rod 20 to the drive shaft 7, and to connect the rod 20 to the drilling head 10. In Figure 1, the concave joint 33 is arranged on the lower end side of the rod body 30 in the upright state, and the convex joint 32 is arranged on the upper end side. Therefore, following this example, the convex joint 32 is installed at the upper end of the drilling head 10, and the concave joint 33 is installed at the lower end of the drive shaft 7.

When constructing a long underground hole H, the rod 20 can be extended by easily adding a rod body 30 using the joint structure 50, and the extended rod 20 can be connected to the drive shaft 7. The procedure for extending the rod 20 by adding a new rod body 30c is described below.

<Procedure for extending the rod body>
As shown in Fig. 7(a), the forward rotational force from the rotating device 8 and the vertical vibration from the vibration generating device 9 are transmitted from the drive shaft 7 through the rod 20 to the drilling head 10 to excavate the ground and construct an underground hole H. Before starting underground drilling, the following preparatory work is carried out.

The drilling mixer 1 is installed so that the leader 4, with the guide 41 placed in an upright position via the telescopic devices 43 and 44, is placed in a predetermined position. Next, the planned drilling position is pre-drilled in advance, the drilling head 10 is inserted, and the rod body 30 is connected to the shaft 11 and drive shaft 7 of the drilling head 10. All of these are connected by providing a joint structure 50, as described above.

Specifically, as shown in Figure 1, the shaft portion 11 and the rod body 30 are connected by fitting the convex joint 32 of the shaft portion 11 with the concave joint 33 of the rod body 30 and attaching a pressing member 40 to them to provide a joint structure 50. Similarly, the rod body 30 and the drive shaft 7 are connected by fitting the convex joint 32 of the rod body 30 with the concave joint 33 of the drive shaft 7 and attaching a pressing member 40 to them to provide a joint structure 50.

During construction, as shown in FIG. 7(a), the stabilizing liquid S is supplied from the fluid supply pipe via the swivel joint to the drive shaft 7, and is then discharged from the fluid outlet 16 into the underground hole H via the rod 20 and the shaft 11 of the drilling head 10. The stabilizing liquid S filling the underground hole H is discharged using a vacuum hose V inserted into the hole. As shown in FIG. 7(b), the drilling head 10 descends as drilling progresses, and when the joint structure 50 formed on the rod 20 approaches the upper end of the chuck mechanism 45, the rotation device 8 and the vibration device 9 are temporarily stopped.

With the rod body 30 constituting the rod 20 being gripped by the chuck mechanism 45, the pressing member 40 is removed from the joint structure 50 connecting the rod body 30 and the drive shaft 7. Once the pressing member 40 has been removed, the lifting body 42 on which the rotation device 8 and the vibration device 9 are installed is raised along the guide 41 as shown in FIG. 7(c). In this way, the convex joint 32 at the upper end of the rod body 30 is exposed, and the concave joint 33 at the lower end of the drive shaft 7 is exposed. In addition, a working space is provided between the concave joint 33 of the drive shaft 7 and the convex joint 32 of the rod body 30 to add a new rod body 30c.

Using this working space, as shown in FIG. 8(a), a new rod body 30c is connected to the drive shaft 7 and the rod body 30 held by the chuck mechanism 45. Specifically, as shown in FIG. 8(b), the convex joint 32 of the rod body 30 held by the chuck mechanism 45 is fitted with the concave joint 33 of the new rod body 30c, and a pressing member 40 is attached to them to provide a joint structure 50. This adds a new rod body 30c, and the length of the rod 20 is extended.

Then, while appropriately adjusting the height position of the drive shaft 7 using the lifting body 42, the convex joint 32 of the new rod body 30c is fitted into the concave joint 33 of the drive shaft 7, and a pressing member 40 is attached to these to provide a joint structure 50. As a result, the rod 20, whose member length has been extended, is suspended from the drive shaft 7, so the chuck mechanism 45 is released, and the rotation device 8 and vibration device 9 are operated as shown in Figure 9 (c), and the work of constructing the underground hole H is resumed.

In this manner, the rod 20 to which the rod body 30 has been added via the joint structure 50 smoothly transmits the forward rotational force from the rotating device 8 and the vertical vibration from the vibration generating device 9, which are applied via the drive shaft 7, to the drilling head 10 connected to the tip of the rod 20. Therefore, even if a hard layer is present in the ground during drilling, the drilling head 10's bit 14 and tip bit 15 to which the vertical vibrations have been transmitted can crush the layer by impact or move large gravel by vibration, making it possible to continue drilling.

The joint structure 50 also employs a retaining member 40 and does not use a pair of connection pins 81 as in the joint structure 80 of the hexagonal joint pin type shown in FIG. 10(b) described as one of the prior art. This makes it possible to shorten the fitting range of the convex joint 32 and the concave joint 33. In other words, when a pair of connection pins 81 is employed, as shown in FIG. 10(b), it becomes necessary to provide a through hole 832 through which the connection pin 81 passes in the square hole portion 831 and a notch 822 through which the connection pin 81 passes in the square tube portion 821, each of which is offset in the height direction. However, the square hole portion 333 and the square tube portion 323 of the joint structure 50 can be omitted, so that the height can be set low, and the fitting range is also reduced.

This allows the length of the pipe material 31 to be increased by the amount of the shortened engagement range of the convex joint 32 and the concave joint 33 without changing the overall length of the rod body 30. This makes it possible to reduce the number of rod bodies 30 that are added to extend the rod 20, even when the construction area is in a low-head space and there is a limit to the amount of work space available for adding the rod body 30. As a result, the number of times the rod body 30 needs to be added can be reduced, greatly improving the work efficiency when constructing the underground hole H and contributing to a shorter construction period.

Furthermore, when drilling a hole in the ground using the drilling mixer 1, if a layer of compacted gravel G is present as shown in FIG. 9(a), the bit 14 and tip bit 15 of the drilling head 10 may bite into the layer of gravel G, or detached gravel may get between the layer of gravel G and the drilling head 10, causing the drilling head 10 to spin freely, making drilling impossible. In such a case, a measure can be taken such as applying a rotational force in the opposite direction around the axis of the rod 20 using the rotating device 8, as shown in FIG. 9(b).

As a result, even if a gravel layer G is present underground, drilling work can be continued without complicated operations, making it possible to significantly improve the workability of drilling holes underground. At this time, since the drilling head 10 has a structure that allows drilling in either the forward or reverse rotation, drilling can be continued with the reverse rotation, or drilling work can be resumed by switching to forward rotation.

The drilling mixer of the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

For example, in this embodiment, as shown in FIG. 4, the square tube portion 323 of the convex joint 32 and the square hole portion 333 of the concave joint 33 are formed in a hexagonal shape, but this is not necessarily limited to this. As long as the shape does not allow the convex joint 32 and the concave joint 33 to rotate relative to each other around their axes, any shape such as a triangular shape or a square shape may be used.

In addition, in this embodiment, the rod body 30 is in an upright position, with the convex joint 32 at the upper end and the concave joint 33 at the lower end, but this is not limited to this. The rod body 30 may be reversed upside down, or a rod body 30 with convex joints 32 at the top and bottom and a rod body 30 with concave joints 33 at the top and bottom may be prepared, and the combination of the two may be connected with a joint structure 50 to form the rod 20.

In addition, in this embodiment, as shown in FIG. 5(a), the pressing member 40 is composed of half-split members 401, 402 and a fastener 403, and a total of four bolts 403a and nuts 403b are used for the fastener 403, but any number of bolts 403a and nuts 403b may be used. Also, as shown in FIG. 6, as long as it is possible to apply a tightening force in the vertical direction to the convex flange 324 and the concave flange 334, the fastener 403 is not limited to the combination of bolts 403a and nuts 403b.

In addition, the half-split members 401 and 402 do not necessarily have to be separate. For example, one of the two sets of ears 401b and 402b may be provided with a hinge member, and the other set may be fastened with a bolt 403a and a nut 403b.

REFERENCE SIGNS LIST 1 Drilling and mixing machine 2 Crawler travelling body 3 Upper rotating body 4 Leader 41 Guide 42 Lifting body 43 Extension device 44 Extension device 45 Chuck mechanism 5 Fluid supply pipe 6 Swivel joint 7 Drive shaft 8 Rotation device 9 Vibration device 10 Drilling head 11 Shaft portion 12 Mixing blade 13 Drilling blade main body 14 Bit 15 Tip bit 16 Fluid discharge port 20 Rod 30 Rod main body 30a Rod main body (lower side)
30b Rod body (upper side)
30c New rod body 31 Pipe material 31a Steel pipe (lower side)
31b Steel pipe (upper side)
32 convex joint 321 hollow portion 322 cylindrical portion 323 square tube portion 324 convex side flange 324a opposing surface 324b abutment surface 33 concave joint 331 hollow portion 332 storage tube portion 333 square hole portion 334 concave side flange 334a opposing surface 334b abutment surface 40 pressing member 401 half-split member 401a fitting groove 401b ear portion 402 half-split member 402a fitting groove 402b ear portion 403 fastener 403a bolt 403b nut 50 joint structure 60 rod packing 70 joint structure (flange type)
71 Flange 72 Flange 73 Bolt 80 Joint structure (hexagonal joint pin type)
81 Connection pin 82 Male joint 821 Square tube portion 822 Cutout portion 83 Female joint 831 Square hole portion G Gravel layer H Ground hole V Vacuum hose E Eyebolt S Stabilizing liquid

Claims (1)

A drilling and mixing machine that excavates ground with a drilling head by applying a rotational force and a vertical vibration to a rod having a drilling head connected to its tip,
The rod has a rod body and a joint structure that connects the rod body in the axial direction,
The joint structure includes:
A convex joint having a flange on an outer peripheral surface and a square tube portion;
A concave joint having a flange on an outer peripheral surface and a square hole portion that fits into the square tube portion;
a pressing member that butts and clamps the flange of the convex joint and the flange of the concave joint,
A drilling and mixing machine characterized in that the cross section where the flange of the convex joint and the flange of the concave joint are butted together is tapered toward the outer periphery.

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