JP5033062B2 - Drilling bit - Google Patents

Description

  The present invention relates to an excavation bit capable of excavating a hole having a diameter of about 10 to 30 cm in a horizontal direction and an oblique direction in addition to a vertical direction with respect to a ground and a natural ground. The excavation bit of the present invention is mainly used in an injection-type steel pipe tip receiving method for wells, foundation piles, survey boring, anchors, and tunnel construction.

  This type of drilling bit is housed in the tip of the casing pipe so that the drilling head is exposed from the tip of the casing pipe, and the base end of the drilling head is connected to one or more long small inner rods connected to each other. Is done. The inner rod is in the casing pipe, and its proximal end protrudes from the casing pipe and is connected to an excavation power device installed on the surface of the earth or the field, and a rotational force and a pressing force are applied from the device. The excavation bit is given rotational force and pressing force via the inner rod. Further, the striking force is applied from the excavation power unit through the inner rod, or is directly applied to the base end of the excavation head from the hammer device of another excavation power unit accommodated in the casing pipe, and the excavation head receives the force and receives the ground.・ Rotating while drilling against natural ground to drill holes.

  Since this excavation head is used together with the casing pipe, the diameter of the drilling hole drilled by the excavation head needs to be larger than the outer diameter of the casing pipe. It is often a structure that can be rotated within a range to expand the diameter. Since this excavation head is made of cemented carbide and is expensive, after the drilling, the diameter-expanded portion of the excavation head is shrunk and pulled up through the casing pipe to be recovered and reusable. The casing pipe is often left in the drilling hole.

With this excavation bit, there is no problem when drilling in the vertical direction, but when drilling in the horizontal or diagonal direction, the diameter of the movable excavation head with the expanded excavation head rotates by its own weight and the diameter is expanded. Therefore, there is a problem that the drilling head is returned to the contracted state and the excavation head cannot be maintained in the expanded state, and the drilling in the expanded state becomes impossible.
JP 2008-38444 A

  The problem to be solved by the present invention is to solve this conventional problem, prevent the return from the expanded state during the excavation operation to the contracted state, and ensure the drilling of the hole in the horizontal and oblique directions. It is to provide a drilling head.

The configuration of the present invention that solves this problem is as follows.
1) In a drilling bit that is attached to the tip movable part of a drilling power device that gives rotation and hammering, and that is provided with the rotational force and hammering force of the drilling power device at the proximal end and drills the ground with the drilling head at the tip,
A movable excavation head that is rotatable within a predetermined range about a position eccentric from the central axis of rotation of the excavation bit is fitted to a part of the excavation head at the tip of the excavation bit, and the movable excavation head is one end of the rotation range. The movable excavation head is within the outer diameter area of the excavation head, and the other end of the rotation range is larger than the outer diameter of the excavation head, and the axial direction is on the outer surface near the rotation center of the excavation head. A sphere that engages with the groove is attached to the excavation bit at a position facing the groove of the movable excavation head in the same expanded state so as to urge it toward the movable excavation head. The excavation bit is characterized in that the expanded state can be maintained by engaging the sphere and the groove at the diameter expansion position. 2) The movable excavation head can be slid in the axial direction. Fitted, In addition, the base end side peripheral edge of the movable excavation head is locked in the notch groove provided in the excavation head at the base end side sliding position in the diameter expansion state of the movable excavation head so that the diameter expansion state can be reliably maintained. In the excavation bit described in 1) above.

  According to the present invention, when the movable excavation head rotates and reaches the angle of the enlarged diameter position, the energized sphere on the excavation head side fits into the groove of the movable excavation head, and the movable excavation head has its own weight or Suppresses rotation in the contraction direction due to light external force. Therefore, even if the excavation head is used horizontally or obliquely, the moment of engagement between the sphere and the groove is superior to the moment of the movable excavation head trying to return to the contraction direction by an external force due to its own weight or light collision. The movable excavation head can maintain the expanded diameter state. When the movable excavation head is contracted to the accommodation position after drilling, the excavation head is rotated in a direction opposite to the rotation direction of the drilling hole, so that the expanded excavation head receives a strong resistance from the ground and has a spherical shape. It is rotated in the direction of contracting against the moment of engagement, and can be collected within the outer diameter of the excavation head.

  In particular, the movable excavation head can slide in the axial direction with respect to the excavation head and the excavation bit, and at the base end side sliding position of the movable excavation head, the peripheral edge of the base end of the movable excavation head in the notch groove of the excavation head When the movable excavation head is engaged, the movable excavation head is engaged with the cutout groove, and the expanded diameter state of the movable excavation head can be more reliably maintained.

The cross section of the groove of the movable excavation head in the present invention is an arc shape that fits into the sphere, and the urging means is generally a ball spring, and the sphere uses a steel ball that does not easily rust, and a hole that accommodates the sphere. Is preferably provided on the wall surface of the movable excavation head housing of the excavation bit, and a ball spring is provided at the bottom of the excavation bit so that the upper sphere can be inserted and retracted.
The engagement between the notch groove of the excavation head and the base end side peripheral edge of the movable excavation head at the diameter expansion position of the present invention has a dimension / position relationship that engages when the excavation head and the movable excavation head become the same striking surface. This may ensure the engagement.
It is practical that the notch groove of the present invention is about 5 mm and the sliding width of the movable excavation head is 6 mm or more.

Further, in order to make the movable excavation head of the present invention rotatable and prevent its falling off, a retaining pin that engages with the base end side peripheral surface of the movable excavation head is attached to the excavation bit in a direction perpendicular to the axial direction. In the invention in which the fitted movable excavation head can slide in the axial direction, the retaining pin and its locking portion are locked with a length of sliding amount.
The number of movable excavation heads of the present invention is preferably two or three in terms of load balance and strength.

  Embodiment 1 of the present invention will be described with reference to the drawings. In the first embodiment, the base end side peripheral edge of the movable excavation head is locked in the notch groove of the excavation head, the movable excavation head can be slid by 5 mm or more in the axial direction after fitting, and the sphere is urged by a ball spring. This is an example. The striking force of the first embodiment is given by an air hammer device housed in a casing pipe. The base end of the air hammer is connected to the inner rod, and air is sent from the air passage inside the inner rod. Further, the engagement between the cutout groove of the excavation head and the peripheral edge on the base end side of the movable excavation head is such that the excavation head and the movable excavation head are engaged at the same striking surface.

FIG. 1 is an explanatory diagram of the first embodiment.
FIG. 2 is a side view of the distal end side of the first embodiment.
FIG. 3 is a side view illustrating the movable excavation head according to the first embodiment.
FIG. 4 is a front view of the excavation bit with the movable excavation head of the first embodiment removed.
FIG. 5 is an explanatory view showing a state of diameter expansion and contraction of the movable excavation head.
FIG. 6 is a side view showing a contracted state of the movable excavation bit.
FIG. 7 is a front view showing a state in which the movable excavation bit is locked in the notch groove.
8A and 8B are explanatory views of the engagement between the sphere and the groove.
FIG. 9 is an explanatory diagram illustrating a usage state of the first embodiment.

In the figure, 1 is a excavation bit, 2 is a movable excavation head, 3 is a casing pipe, 3β is a contact surface that contacts the contact surface 2α of the movable excavation head 2 at the tip of the casing pipe 3, and 4 transmits rotational force and pressing force. The inner rod is an air passage 4a, and the base end thereof is connected to a rotary pressing device (not shown) which is an excavation power device installed in the field. Reference numeral 5 denotes a pneumatic hammer device which is accommodated below the casing pipe 3 and directly applies a striking force to the base end of the excavation bit 1, 5a is a cylinder, and 5b is a hammer piston. 1a to 1p are constituent parts of the excavation bit 1, 1a is an excavation head at the distal end portion of the excavation bit 1, 1b is a shank at the proximal end portion of the excavation bit 1, and 1c is a meshing surface of the inner surface of the distal end of the cylinder 5a of the hammer device 5 1d is an air passage lower valve attached to the base end of the excavation head 1a, 1e is an air passage formed inside the excavation bit, 1f is a movable excavation head 2 ₁ f ₁ is a hole for inserting the rod-like portion 2 b at the proximal end of the movable excavation head 2 in the accommodation space ₁ f, 1 g is a wall surface of the accommodation space, and 1 h is attached to the distal end surface of the excavation head 1 a. The excavation tip, 1i is a retaining pin that engages with the peripheral surface of the rod-like portion 2b at the base end of the movable excavation head 2, 1j is a sphere using a steel ball, 1k is a hole for accommodating the sphere, and 1l is the same hole. Ball spring inserted in the bottom of the 1m is a notch groove provided on the peripheral edge of the base end side of the excavation head 1a forming the wall surface 1g of the accommodating space 1f, 1n is a central axis that is the rotation center of the excavation bit 1, 1o is a striking surface from the hammer device 5, 1p is a step part which transmits a striking force and a pressing force from the excavation bit 1 to the casing pipe 3.

In the figure, 2A～2arufa is a component of the movable drilling heads 2, 2a is the rotational center line which is eccentric of the movable drilling heads 2, 2b is movable drilling head 2 is inserted into the hole 1f ₁ of the accommodation space 1f A base rod-like portion, 2c is a drilling tip attached to the tip of the movable excavation head 2, and 2d is a width that can slide in the direction of the rotation center line by an engagement groove with a retaining pin 1i formed on the surface of the rod-like portion 2b. Have 2e is a groove that engages with the sphere 1j, extends long to the engagement groove 2d, and is open on the base end side. Reference numeral 2f denotes a base-side peripheral edge of the movable excavation head 2 that engages with the cutout groove 1m of the excavation head 1a, and 2α denotes a contact surface of the movable excavation head 2 that contacts the contact surface 3β of the tip of the casing pipe 3.

  In the first embodiment, an excavation power device (not shown) on the ground surface (ground) side applies rotation and pressing force to the inner rod 4. The rotation of the inner rod rotates the cylinder 5a of the hammer device 5, and the rotational force is transmitted to the excavation bit 1 by the inner surface of the lower end of the cylinder 5a and the fitting portion 1c of the excavation bit 1, and the pressing force is also applied to the inner rod 4 and the cylinder. It is given to the drill bit 1 via 5a. The hammer piston 5b of the hammer device 5 accommodated in the casing pipe 3 attached above the excavation bit 1 is applied by hitting the striking surface 1o at the base end of the excavation bit 1. A part of the striking force is given to the casing pipe 3 through the middle step 1p of the excavation bit 1. Thus, the excavation bit 1 is rotated, hit, and pressed, and the ground is excavated by the excavation tips 1h and 2c of the head.

When not used and when the excavation bit 1 is recovered after drilling, the movable excavation head 2 rotates around its eccentric rotation center line 2a as shown in FIG. 6 and fits in the accommodation space 1f of the excavation head 1a. Rotation of the movable drilling head 2 can be rotated in an angular range of degree inserted and 90 ° to the hole 1f ₁ of the base end side of the rod portion 2b of the base end thereof accommodating space 1f. The movable excavation head 2 is prevented from falling off from the accommodation space 1f in the distal direction by the retaining pin 1i being locked by the engaging groove 2d in the rod-like portion 2b. In this retracted storage position, the sphere 1j is pressed by the outer peripheral surface of the rod-like portion 2b and pushed in the direction of the flange 1k, and is in a non-engaged state (see the state of FIG. 8B). .

  The movable excavation head 2 moves in the direction of contraction by rotating the excavation bit 1 in a direction opposite to the rotation direction during excavation (rotating clockwise in FIG. 2), thereby increasing the diameter of the movable excavation head. 2, even if the spherical body 1j is engaged with the groove 2e, the movable excavation head 2 is rotated in the contraction direction (counterclockwise) by overcoming the engagement force. The contracted state is shown in FIG.

  In this contracted state, the movable excavation head 2 is accommodated within the outer diameter of the excavation head 1a, and the casing pipe 3 is pulled in the proximal direction as it is, recovered and reusable.

Next, when performing excavation work, it is necessary to change from the contracted state of FIG. 6 to the expanded state of FIG. 2, so that the excavation head 1a and the movable excavation head 2 of the excavation bit 1 are pressed against the ground, and then the inner rod 4 is It is rotated counterclockwise (excavation rotation direction) in FIG. Due to the rotation of the inner rod 4, the excavation bit 1 and the excavation head 1a at the tip thereof are forcibly rotated against resistance with the ground. On the other hand, the movable drilling heads 2 by the resistance due to contact with the ground, the rod portion 2b is in a state of non-rotating escaped by relative rotation of the hole 1f _1. Therefore, the movable excavation head 2 is in a relative rotation state with the excavation bit 1 and the excavation head 1a and is in a contracted state (position) that fits in the accommodation space 1f of FIG. At this position, as shown in FIG. 8A, the sphere 1j is fitted into the groove 2e formed in the rod-like portion 2b, and the state is maintained by the ball spring 2j. If it will be in this state, the latching force by the spherical body 1j will prevail over the force which tries to return to a contraction direction with the dead weight of the movable excavation head 2, and it will not return with the dead weight of the movable excavation head 2.

  If the excavation bit 1 is rotated counterclockwise in this expanded diameter state, the expanded diameter state is more firmly held by the resistance from the ground, and the ground is drilled by the heads 1a and 2 by the expanded diameter.

  In the first embodiment, this enlarged diameter state is obtained when the distal end surface of the excavation head 1a is flush with the distal end surface of the movable excavation head 2, and the base end peripheral edge 2f on the excavation head 1a side is 5 mm. By engaging in the notch groove 1m and forcibly constraining the expanded diameter state, the expanded diameter state can be maintained more reliably.

After drilling, the contact surface 2α of the movable excavation head 2 and the contact surface 3β at the tip of the casing pipe 3 are brought into contact with each other by pulling the inner rod 4 toward the base end side by 6 mm or more. At the same time, the base peripheral edge 2f of the movable excavation head 2 is detached from the fitted cutout groove 1m.
Thereafter, when the inner rod 4 is rotated clockwise in FIG. 2, the contact surface 2α of the movable excavation head 2 is in contact with the contact surface 3β of the casing pipe 3, so that the movable excavation head 2 is rotated by the resistance of the contact. Instead, only the excavation head 1 a and the excavation bit 1 are forcibly rotated by the rotation of the inner rod 4. Thereby, the movable excavation head 2 rotates relative to the excavation bit (head) around the rod-like portion 2b and the rotation center line 2a and escapes, and the movable excavation head 2 moves relative to the excavation head 1a and the excavation bit 1. The contracted state of FIG. 6 is rotated counterclockwise.
When the inner rod 4 is pulled in the proximal direction after this state, the excavation bit 1, the movable excavation head 2, and the hammer device 5 can pass through the casing pipe 3 and be collected.

As described above, the excavation bit 1 of the first embodiment is used horizontally and obliquely so that the movable excavation head 2 moves in the contraction direction by the engagement of the sphere 1j and the groove 2e, and the notch groove 1m and the proximal end. By maintaining the double widened state by restraint by the fitting of the peripheral edge 2f, it is possible to reliably drill holes even when excavating horizontally and obliquely while maintaining the expanded diameter state during use. . No contraction occurs during excavation.
Further, in the present invention, those having no cutout groove 1m are also included.

  The present invention can also be used for anchor holes in slopes and drilling in injection-type steel pipe tip receiving methods at tunnel faces. Further, when the casing pipe is not used, it can be used even when the internally housed hammer device is integrated into the ground (surface) excavation power device.

2 is an explanatory diagram of Embodiment 1. FIG. 3 is a side view of the distal end side of Embodiment 1. FIG. It is a side view which shows the movable excavation head of Example 1. FIG. It is a front view of a excavation bit in the state where a movable excavation head of Example 1 was removed. It is explanatory drawing which shows the state of diameter expansion and contraction of a movable excavation head. It is a side view which shows the contraction state of a movable excavation bit. It is a front view which shows the state which the movable excavation bit latched in the notch groove. It is explanatory drawing of engagement of a spherical body and a groove | channel. FIG. 3 is an explanatory diagram illustrating a usage state of the first embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excavation bit 1a Excavation head 1b Shank 1c Fitting part 1d Lower valve 1e Air path 1f Accommodating space 1f ₁ hole 1g Wall surface 1h Excavation tip 1i Detachment pin 1j Sphere 1k hole 1l Ball spring 1m Notch groove 1n Center axis 1o DESCRIPTION OF SYMBOLS 1p Step part 2 Movable excavation head 2a Rotation center line 2b Rod-shaped part 2c Excavation tip 2d Engagement groove 2e Groove 2f Base end periphery 2α Contact surface 3 Casing pipe 3β Contact surface 4 Inner rod 4a Air path 5 Hammer device 5a Cylinder 5b Hammer piston

Claims (2)

In the excavation bit which is attached to the distal end movable part of the excavation power device which gives rotation and impact, and the rotational force and impact force of the excavation power device is given to the base end and excavates the ground with the excavation head at the distal end,
A movable excavation head that is rotatable within a predetermined range about a position eccentric from the central axis of rotation of the excavation bit is fitted to a part of the excavation head at the tip of the excavation bit, and the movable excavation head is one end of the rotation range. The movable excavation head is within the outer diameter area of the excavation head, and the other end of the rotation range is larger than the outer diameter of the excavation head, and the axial direction is on the outer surface near the rotation center of the excavation head. A sphere that engages with the groove is attached to the excavation bit at a position facing the groove of the movable excavation head in the same expanded state so as to urge it toward the movable excavation head. An excavation bit characterized in that an expanded state can be maintained by engaging the spherical body and the groove at an expanded diameter position of an excavation head. The movable excavation head is fitted so as to be slidable in the axial direction, and the proximal side of the movable excavation head is inserted into the notch groove provided in the excavation head at the proximal end sliding position in the expanded state of the movable excavation head. The excavation bit according to claim 1, wherein the peripheral edge is locked so that the expanded diameter state can be reliably maintained.

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