JPS6232314B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutter head for a vertical hole boring machine, and more particularly to a cutter head for a boring machine used in a reverse circulation method.

The reverse circulation method is used, for example, to drill vertical holes for foundation piles in buildings. In the case of large-sized buildings, foundation piles for buildings are embedded into the bedrock layer below the general soil layer. However, the cutting head of the boring machine used in the reverse circulation drilling method is divided into one for general soil and one for rock, and the current situation is that the cutting head is changed depending on the soil type. .

The present invention provides a cutter head for a vertical hole boring machine that can excavate ground ranging from ordinary soil to soft rock without replacing the cutter head.

The cutter head of the present invention includes a hollow and open-ended main shaft, a supporting member forming acute angles α and β with respect to the horizontal and vertical planes, and arranged in a radial direction with respect to the main shaft, and having an end fixed to the circumferential surface of the main shaft. A pilot cutter provided at the lower end of the main shaft, a stabilizer supported by the main shaft, a gauge cutter located at the outermost side and provided on the support member,
A rotary cutter consisting of a cutter located between the gauge cutter and the main shaft and attached to the support member, and rotatably disposed on the support member so that the cutter gradually increases in radius from the center of the main shaft; and drag cutters arranged in a distributed manner on each support member so as to be close to the rotary cutter and closely adjacent to each other, and the gauge cutter and the rotary cutter are located within a conical surface that shares a central axis with the gauge cutter and the rotary cutter. It consists of a disk with teeth on its peripheral surface having inclined sides, and is arranged so that the distance between the lowest tooth and the support member is longer than the distance between the cutting edge of the drag cutter and the support member. There is.

When excavating rock, the rotary cutter and the gauge cutter penetrate the rock before the drag cutter, generate and loosen cracks in the rock, and cut the rock, and the drag cutter can cut the loosened rock. In general soil, the sloped sides of the teeth of the rotary cutter and the gauge cutter displace earth and sand, loosening the soil and cutting it, and then the drag cutter can excavate the loosened soil. the result,
It is possible to excavate anything from soft rock to general soil without replacing the cut head.

Furthermore, since the rotary cutter and the gauge cutter excavate while rotating, and the drag cutter excavates the ground loosened by the rotary cutter, the digging resistance of the drag cutter itself is small, and in addition, the cutters are arranged dispersedly on the support member. Since the spacing between the cutters is widened, the digging resistance of the entire cutter head is extremely small, the life of the cutters is extremely long, and the power consumption can be reduced.

An embodiment of the cutter head of the present invention will be described below with reference to the accompanying drawings.

The cutter head of the present invention is incorporated into a boring machine used in the reverse circulation drilling method. FIG. 1 shows a typical example of such a boring machine.

The pedestal 1 is installed on the ground surface. A rotating table 2 is supported by a pedestal. The drill pipe 3 is attached to a rotary table so as to be movable in its axial direction. A cutter head 4 is attached to the end of the drill pipe that is underground, and a swivel joint 5 is attached to the end that is above the ground. The drill pipe and cutter head are suspended by a crane (not shown). The cutter head has a main shaft 6 connected to the drill pipe.
A support member or wing 7 is attached to the spindle and a pilot cutter 8 is attached to the lower end of the spindle.

Boring is carried out by rotating a rotary table on a pedestal, lowering the drill pipe together with the cutter head under its own weight, and causing the cutter array on the support member to excavate the ground. When excavating,
The pilot cutter and the gauge cutter provided on the outermost periphery of the support member prevent eccentric rotation of the cutter head, and the stabilizer 9 guides the cutter head so that the hole can be dug immediately.

In order to discharge excavated earth and sand from the vertical hole, a discharge pipe 10 is connected to the upper end of the drill pipe via a swivel joint, and an air supply pipe 10A is connected to the drill pipe. The discharge is caused by the compressed air sent to the air supply pipe by the air compressor 10B on the ground surface being ejected into the drill pipe, and due to the action of this ejected compressed air, earth and sand etc. excavated in the vertical hole are discharged. The water is sucked into the main shaft of the cutter head along with the water in the hole, and is discharged to the surface through a drill pipe and a discharge pipe. Note that, instead of this air lift drilling, the discharge may be carried out using only a suction pump connected to a discharge pipe without an air compressor or an air supply pipe, so-called pump suction drilling.

Figures 2-4 show details of the cutter head of the present invention. The main shaft 6 consists of a hollow, open-ended pipe, and a flange 11 provided at the upper end is bolted to a flange at the lower end of the drill pipe 3. The support member 7 forms an acute angle α with the horizontal plane and an acute angle β with the vertical plane, is positioned in a radial direction with respect to the rotation center axis of the main shaft, and has an end welded to the circumferential surface of the main shaft. ing. reinforcing plate 12,
12' connects the free end of the support member and the circumferential surface of the main shaft, and the fixed end of the support member and the circumferential surface of the main shaft. The support member and reinforcing plate 12 have bolted extensions 13, 14 so that they can be disassembled for transport. The stabilizer 9 is integrally connected to these extensions. The gauge cutters 20 are arranged on the outermost periphery of each support member so as to be equally spaced from each other. A cutter array is provided on each support member located between the gauge cutter and the spindle. Each cutter array is composed of a rotary cutter 21 and a drag pick or drag cutter 22. The rotary cutter is attached to the support member so that it can rotate freely, and the drag cutter is attached to the support member by welding.

The rotary cutter consists of a disk having teeth 23 on its circumference, which are generally triangular or trapezoidal in axial cross section, as best shown in FIGS. 5 and 6. Each tooth is arranged radially with respect to the central axis of the cutter. The tip 24 of each tooth is located on a cylindrical surface parallel to the central axis of the cutter or sharing the same center axis with the central axis of the rotary cutter. One side 25 of each tooth is formed as a flat surface perpendicular to the central axis. However, the other side is a slope 26. These slopes are located within a conical surface with its apex on the central axis of rotation of the cutter. The angle γ that the side surface 26 of the tooth makes with the plane or the side surface 25 perpendicular to the central axis of the rotary cutter is 15° to
It is desirable to select a range of 45°.

As described above, the gauge cutter and each rotary cutter are attached to the support member so as to be freely rotatable. For this purpose, each cutter has a shaft 27
The shaft is attached to the support base 28 via a bearing.
The support base is bolted to a base 29 that is welded and fixed to the support member.

Each rotary cutter is generally arranged such that the sloped side of the teeth faces in the direction of slope of the support member;
A rotary cutter is arranged so that its center axis passes through the center axis of rotation of the cutter head, but a rotary cutter is arranged so that its center axis of rotation passes through the center axis of rotation of the cutter head, as will be explained in detail later. It is preferable.

In the cutter head according to the present invention, the gauge cutter located at the outermost end from the rotation center axis of the cutter head is also composed of teeth with inclined side surfaces and a disk on the peripheral surface, just like the rotary cutter. The distance between the support member and the lowermost edge is the same as that of the rotary cutter. but,
The inclined sides are arranged so that they lie on a vertical plane.

A known drag cutter or drag pick can be used. For example, blades with a chisel-like edge or with a conical end may be used alone or in combination. FIGS. 7A to 7C show several examples of drag cutters with chisel-like cutting edges. The drag cutter shown in FIG. 7A is almost like a chisel and has a flat rake face 22a and a flat nipped face 22b. In the drag cutter shown in FIG. 7B, a rake face 122a is formed in an inverted V shape or a roof shape, thereby forming a laterally bent face, but a flank face 122b is flat. The drag cutter shown in FIG. 7C has a flat rake surface 222a, but a curved surface 222b. FIG. 7D shows a drag cutter in which the cutting edge is formed into a conical end, and the cutting edge portion 322a can rotate around an axis.

As clearly shown in FIG. 8, the drag cutter is attached to the support member by welding and fixing the portion far from the cutting edge to the support member.

Each rotary cutter has the tip 24 of the lowermost tooth.
is located on a plane perpendicular to the rotation center of the main shaft, and each drag cutter is also arranged such that its cutting edge is located on a plane perpendicular to the rotation center axis of the main shaft. Therefore, the tooth tips and cutting edges of the cutters in each array are located on a plane or excavation surface that is perpendicular to the rotation center axis of the main shaft and parallel to the rotation center axis. However, in the cutter head of the present invention,
For all rotary cutters, the distance H ₂₁ from the tip of the lowermost tooth to the lowermost edge 7A of the support member (distance in the direction parallel to the rotation center axis of the cutter head) is the distance from the cutting edge to the lowermost edge of the support member for all drag cutters. The distance to the ground is longer than H ₂₂ , and each cutter is arranged so that during boring, the rotary cutter contacts the ground first, and then the drag cutter contacts the ground.

A plurality of drag vines, for example four drag vines, are arranged adjacent to the rotary vines. These drag cutters are arranged in close proximity to the rotary cutters, with some overlap if necessary.

The rotary cutter and the drag cutter are arranged in a dispersed manner on the support member in order to prevent dirt from clogging between the cutters and to allow the cutter to be easily attached to the support member. FIG. 9 shows details of the arrangement of the cutters, and each support member, each rotary cutter, and each drag cutter is indicated by a decimal numeral attached to each reference numeral. The drag cutter next to the rotary cutter 21 ₁ of the support member 7 ₁ is the drag cutter 22 ₁₁ on the support member 7 ₂ , and the drag cutter next to the cutter 22 11 is the drag cutter 22 ₁₁ on the support member 7 1.
₃ is drag cutter 22 ₁₂ , and cutter 22
The drag cutters 12 and ₁₂ are the drag cutters 22 _{and 13} on the support member ₇₄ , and the drag cutters 22 and 13 are located on the support member 74.
Drag cutters 13 and ₁₃ adjacent to each other are arranged on each support member, such as 22 _{and 14} on support member ₇₁ . Further, the rotary cutters 21 ₂ on the support member 7 ₂ are arranged next to the drag cutters 22 ₁₄ , and the drag cutters 22 2 on the support member 7 ₃ are arranged next to each other.
₂₁ , drag cutters 22 ₂₂ of support member 7 ₄ , drag cutters 22 ₂₃ of support member 7 ₁ and support member 7 ₂
The drag cutters 22 _{to 24} are placed one after another. Similarly, the rotary cutter 2 on the support member ₇₃
1 ₃ has drag cutters 22 ₃₁ , 22 ₃₂ , 22 ₃₃ ,
22 ₃₄ is attached to the rotary cutter 21 ₄ , drag cutters 22 ₄₁ , 22 ₄₂ , 22 ₄₃ , 22 ₄₄ are attached to the rotary cutter 21 4, and drag cutters 22 ₅₁ , 22 ₅₂ , 2 are attached to the rotary cutter 21 ₅ .
2 ₅₃ , 22 ₅₄ , the rotary cutter 21 ₆ has drag cutters 22 ₆₁ , 22 ₆₂ , 22 ₆₃ , 22 ₆₄ , and the rotary cutter 21 ₇ has drag cutters 22 ₇₁ , 22
₇₂ , 22 ₇₃ , 22 ₇₄ , and rotary cutter 2
1 ₈ has drag cutters 22 ₈₁ , 22 ₈₂ , 22 ₈₃ ,
22 _{and 84} are arranged on the support member so as to be adjacent to each other. The innermost drag cutter among the drag cutters attached to each rotary cutter is also arranged so as to be in close contact with the adjacent rotary cutter. In the drawing, the cutter 22 ₁₄ and the cutter 21 ₂ , the cutter 22 ₂₄ and the cutter 21 ₃ , the cutter 22 ₅₄ and the cutter 21 ₆ , the cutter 22 ₆₄ and the cutter 21 ₇ , and the cutter 22 ₇₄ and the cutter 21 ₈ are close to each other. It is located in Therefore, the rotary cutter is arranged so that the radius gradually increases from the rotation center axis of the cutter head, and the drag cutter is arranged so that the radius gradually becomes larger from the rotation center axis so as to fill the space between the rotary cutters. There will be.

The shape of the rotary cutter itself and the arrangement of the rotary cutter and the drag cutter are such that when the cutter head is rotated and moved, the rotary cutter first excavates the ground while rotating, and then the drag cutter of each cutter array excavates the ground by the rotary cutter. The left-over part will be excavated, and this will be repeated to form vertical hole borings.

Figures 10 and 11 show the excavation state of each cutter into the rock mass. As mentioned above, the cut head is subjected to vertical loads during excavation.
Therefore, the rotary cutter 21 penetrates into the rock mass 31 before the drag cutter 22, causing a crack 32 in the rock mass, and the inclined side surface of the rotary cutter causes a shear fracture in the rock mass. At the same time, the rotary cutter is rotated in the direction of the arrow by the rotation of the main shaft, and while cutting the rock with its teeth, the grooves between the teeth cut the rock.
Send 3 backwards. As the cutter head continues to rotate further, the drag cutter cuts the rock 34 that has been loosened by the aforementioned crack occurrence. These steps are repeated until the bedrock is bored. The loosening of the rock by the sloping side of the rotary vine actually extends only to the area excavated by the adjacent drag vine and the side of the next drag vine, but the area excavated by the third and fourth drag vines is as follows: It is loosened by a rotary cutter that cuts the material.

On the other hand, for ordinary soil, the rotary ivy first loosens the soil by displacing earth and sand with its sloping sides, and excavates the soil with its teeth. Then, the drag cutter can sequentially cut the loosened clay. During excavation, the gauge cutter 20 cooperates with the pilot cutter 8 to prevent center runout of the cutter head and to cut while loosening the outermost diameter of the hole.

The cutter head according to the present invention not only enables excavation in bedrock or ordinary soil without replacing the cutter head, but also because the drag cutter excavates the ground loosened by the rotary cutter. Since the rotary cutter and gauge cutter excavate while rotating, their digging resistance is also small.As a result, the digging resistance of the entire cutter head is reduced, the power can be reduced, and the life of the cutter can be reduced. It can be long.

To further improve the life of the rotary cutter, each rotary cutter preferably has its central axis offset with respect to an axis orthogonal to the central axis of rotation of the cutter head, as described above. FIG. 12 shows details of such an arrangement. The central axis A of the rotary cutter is arranged so as to form an angle θ with respect to the axis B perpendicular to the rotation center axis of the cutter head, so that only a point M on the flat side of the teeth penetrated into the ground contacts the excavated ground. , so that the flat side of the tooth gradually moves away from the side C of the excavated ground as it moves from this point to the opposite point M'. As a result, the teeth contributing to the excavation of the ground or teeth other than the teeth are prevented from repeatedly coming into contact with the excavated ground, thereby improving the life of the rotary vine. The angle θ is generally preferably chosen to be between 0.5° and 10°.

In the cutter head of the present invention, the rotary cutter may be composed of a plurality of rotary cutters arranged coaxially. FIG. 13 shows a concrete structure of such a rotary cutter. The rotary cutters 121A and 121B have the same configuration and are integrally formed on one shaft portion 121C. A shaft is fixed to the support base 128, and a shaft portion 121C of the cutter is attached to this shaft via a bearing. In addition, the rotary cutter is close to the main shaft, for example, in _FIG .
The rotary cutters shown at ₁₇ and ₂₁₈ may be constructed from widely used solid discs with pointed circumferential surfaces. It is also good to reduce costs.

[Brief explanation of the drawing]

The drawings show one embodiment of the cutter head of the present invention, and FIG. 1 is an explanatory diagram showing the configuration of a reverse circulation drill device equipped with this cutter head, and FIG. 2 is a plan view of the cutter head of the present invention. 3 is a side sectional view of the cutter head of the present invention partially cut away along the line of FIG. 2;
The figure is a bottom view of the cutter head of the present invention, FIG. 5 is an enlarged side view of the rotary cutter in the cutter head of the present invention, and FIG.
Figure - Front view of rotary ivy along the line, No. 7
Figures A to D are perspective views showing some examples of drag cutters used in the cutter head of the present invention;
Fig. 8 is an enlarged side view of the drag cutter along the line shown in Fig. 3, Fig. 9 is an explanatory diagram showing the arrangement relationship between the rotary cutter and the drag cutter in the cutter head of the present invention, and Fig. 10 is the state of excavation seen from the side of the cutter. , FIG. 11 is an explanatory diagram showing the state of excavation seen from the front of the cutter, FIG. 12 is an explanatory diagram showing the positional relationship between the rotary cutter and the cutter head in the cutter head of the present invention with respect to the rotation center axis, and FIG. 13 is an explanatory diagram showing the arrangement of the cutter head of the present invention FIG. 6 is a front view showing another configuration of the rotary cutter in the cutter head of the present invention. 4... cutter head, 6... main shaft, 7... support member,
8... Pilot cutter, 9... Stabilizer, 20
...Gauge cutter, 21...Rotary cutter, 22...
Drag cutter, 23...tooth, 26...slanted side of tooth.

Claims (1)

[Claims] 1. A hollow and open-ended main shaft, a support member that forms acute angles α and β with respect to the horizontal and vertical planes, is arranged in a radial direction with respect to the main shaft, and has an end fixed to the circumferential surface of the main shaft, and is provided at the lower end of the main shaft. A pilot cutter, a stabilizer supported by the main shaft, a gauge cutter located at the outermost side and provided on the support member, and a cutter located between the gauge cutter and the main shaft and attached to the support member, A rotary cutter is rotatably disposed on a support member so that the cutter gradually increases in radius from the center of the main shaft, and a rotary cutter is disposed on each support member so as to be closely adjacent to the rotary cutter and closely adjacent to each other. The gauge cutter and the rotary cutter have drag cutters disposed on the disk, and the disk has teeth on its circumferential surface with inclined sides located in a conical surface that shares a center axis with the center axis of the gauge cutter and the rotary cutter, and has a lowermost tooth and a support. A cutter head for a vertical hole boring machine characterized by being arranged such that the distance from the drag cutter to the member is longer than the distance between the cutting edge of the drag cutter and the supporting member.