JP3225027B2 - Drilling head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavating head connected to the lower end of a drive shaft such as an earth auger for excavating an underground hole by forward rotation and opening and closing a diameter-enlarging blade by reverse rotation.

[0002]

2. Description of the Related Art An earth auger for excavating an underground hole is formed by winding a spiral blade around a drive shaft, attaching a drill bit to the lowermost end of the spiral blade, and rotating the drill bit around the axis of the drive shaft. This is an underground hole excavation machine that excavates an underground hole by rotation, lifts excavated earth and sand along a drive shaft with a spiral blade, and transports the excavated earth to the ground.

[0003] This earth auger is only for drilling an underground hole within the radius of the spiral blade with the drill bit.
It is known that the so-called bulb portion cannot be formed by expanding the diameter near the lowermost end of the underground hole. In order to drill an underground hole having a bulb portion, after drilling an underground hole having a predetermined diameter in advance, a part of the drilling head in the underground hole is projected outward in the radial direction to perform drilling again. Expanding hole excavators or devices with an installation procedure such as starting are known.

[0004]

However, since the drilling head tends to be large and complicated, the drilling hole drilling machine or the drilling machine has an underground hole having a radius enough to drill with an earth auger. This method is not suitable for creating a so-called bulb by excavating the vicinity of the lower end.

Accordingly, an object of the present invention is to make it possible to form a diameter-enlarged hole as a bulb at the lowermost end of a ground hole having a constant diameter excavated by an earth auger.

[0006]

According to a first aspect of the present invention, an excavating head is connected to a lower end of a drive shaft such as an earth auger to excavate an underground hole by forward rotation.
A drilling head that opens and closes by rotating a diameter-enlarging blade in a reverse rotation and pulling up in a forward rotation to bite into an inner wall of an underground hole, and the drilling head is directly or indirectly connected and fixed to a lower end portion of the drive shaft. An outer cylinder, an inner cylinder coaxially fitted into the outer cylinder, and rotatable within a predetermined angle; and an upper cylinder, which is vertically separated and fixed to the inner cylinder near a lower end of the outer cylinder. A guide body comprising a pair of flanges having a circular portion, and a collar body rotatably loosely fitted to the inner cylinder body between the flange portions and axially pivotally mounting the enlarged blade in the vertical direction. A cam plate which is in contact with the flange portion and is connected and fixed to a lower end portion of the outer cylindrical body; and a cam portion formed on the cam plate is slidably contacted with a projection formed on the end portion thereof. A rotating base of the enlarged-diameter blade and a forward rotation of the drive shaft abutting on the rotating base to be transmitted to the collar body; A swivel stopper provided on the guide body, an upright positioning means for the enlarged-diameter blade, and spiral blades wound around and fixed to the outer cylinder and the inner cylinder, respectively. .

According to a second aspect of the present invention, the means for positioning the enlarged diameter blade is provided with an enlarged diameter blade bracket for rotatably supporting a rotating base portion of the enlarged diameter blade on the collar body. Is erected substantially parallel to the cylindrical body, and a through-hole is formed through the rotating base and the enlarged-diameter blade bracket. The through-hole is previously inserted into the through-hole and deformed under a load of a predetermined load. And a possible wire.

Accordingly, the underground hole of a predetermined diameter is excavated by the forward rotation of the drive shaft, and the enlarged blade is opened by the reverse rotation to excavate the enlarged hole. When the excavating head is lifted, the diameter-enlarging blade rotates and hangs down, and the excavating head can be lifted to the ground via a ground hole while rotating forward.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 3, the excavating head 1 includes an outer cylindrical body 3 having a lower end portion of a drive shaft 2 such as an earth auger, which is detachably coupled to an upper end portion, and a coaxial fitting within the outer cylindrical body 3. Inner cylinder 4 and outer cylinder 3
A guide body 5 fixed to the inner cylinder body 4 near the lower end thereof, and a collar body 6 rotatably fitted to the inner cylinder body 4 within the guide body 5 and rotatable.
And a large-diameter blade 7 pivotally mounted on the collar body 6 so as to be rotatable in the vertical direction, and a spiral blade wound around the outer peripheral portions of the outer cylindrical body 3 and the inner cylindrical body 4 in a series. 8a, 8b
And The spiral blades 8a, 8b
7 is arranged so as not to cause any trouble when rotating upward and downward substantially parallel to the outer cylinder 3 and the inner cylinder 4.

The outer cylinder 3 has a connecting flange 1 at its upper end.
The coupling block 11 for coupling the drive shaft 2 to the coupling flange 10 is coupled to the coupling block 11 with a bolt nut (not shown), and the spiral blade 8a is wound around the outer periphery and fixed. The cam plate 12 is connected to the portion. Cam plate 12
As shown in FIG. 3, projecting portions 14, 14 are provided radially opposite to each other in a diametrical direction with the outer cylindrical body 3 as a center, and an arc-shaped tension is applied from the projecting portion 14 in a counterclockwise direction. Ide 1
5 and a single plate body formed with a rotating base pressing portion 13.

The inner cylindrical body 4 has a pair of outer splines 16, 16 at least in diametrically opposed relation to each other at the upper end thereof, and these are fitted and fixed to the inner peripheral surface of the upper end of the outer cylindrical body 3. The outer splines 16, 16 are engaged with the concave portions 19, 19 of the tube 18 formed between the inner splines 17, 17 formed diametrically opposite to each other.
Rotation within a predetermined angle (90 degrees) is mutually inserted until the inner splines 17 and 17 come into contact with each other, and the rotation of the outer cylinder 3 is transmitted to the inner cylinder 4. Further, the outer splines 16, 16 are slidably contacted with the concave portions 19, 19 to prevent the inner cylindrical body 4 from coming off. A guide body 5 is connected to the inner cylindrical body 4, and a spiral blade 8 b is fixedly wound around an outer peripheral portion of a lower portion of the guide body 5 . Spiral blade 8
A tip drill bit 9 is connected to the lower end of b.

The guide body 5 is formed by vertically separating a top plate 22a and a bottom plate 22b, each consisting of a pair of flanges having a missing circle, by a predetermined distance, and these upper and lower plates 22a, 22b.
An annular collar body 6 is interposed therebetween and is loosely fitted coaxially with the inner cylinder body 4, and the collar body 6 is freely rotatably engaged with both the outer cylinder body 3 and the inner cylinder body 4. . The upper plate 22a and the lower plate 22b oppose each other in the diametrical direction of the inner cylindrical body 4 and are connected and integrated by a pair of swivel stoppers 23,23.

The collar body 6 has a rotating base 25 connected to the radially enlarged blades 7, 7 which are diametrically opposed to each other. When the enlarged blade 7 is rotated upward (see the phantom line in the drawing), the enlarged blade brackets 26 and 26 penetrate through the enlarged blade bracket 26 and the rotation base 25 in a series. Are formed in the respective holes. The diameter-enlarging blade 7 has a saw-toothed uneven portion on both sides, and has a tapered surface 7a directed upward or downward, and the cross section of the tip portion is an acute angle. Then, the rotation base 25 can rotate and come into contact with the projection 14 of the cam plate 12,
When the cam plate 12, that is, the outer cylindrical body 3 rotates, the arc portion 14 of the cam plate 12 changes the turning base 25 from the standing position to the falling position, and presses and regulates the turning base pressing portion 13. For this purpose, a lever 29 is provided which is inclined toward the cam plate 12.

Next, the operation of the excavating head 1 having the above configuration will be described. Before starting the excavation of the underground hole, expand the blade 7,7
Is kept upright. This is achieved by inserting a wire through the through hole 28 formed in the enlarged diameter blade bracket 26 and the rotation base 25 by setting the state shown by the phantom line in the upper side in FIG. A wire that is easily deformed under a predetermined load is used. In this state, as shown in FIG. 4, the guide body 5 is displaced by approximately 90 degrees with respect to the position of the rotation base 25, and the swivel stoppers 23, 23 are moved to the rotation base 25,
25, and as shown in FIG. 5, the projections 14, 14 of the cam plate 12 are
5 abuts.

Therefore, as shown in FIG. 8A, the shaft 2 of the earth auger 30 is connected to the connecting block 11 of the excavating head 1 and the appropriate excavating bit 9 is connected to the lower end of the inner cylinder 4. And the shaft 2 of the earth auger 30
Is driven forward (clockwise) to excavate an underground hole 31 of a required depth. At this time, the rotation of the outer cylinder 3 is transmitted to the inner cylinder 4 by contact between the inner spline 17 and the outer spline 16, while the rotation of the cam plate 12 at the lower end of the outer cylinder 3 is performed as shown in FIG. The protrusion 14 is the rotation base 2
4, the swivel stopper 23 pivots to contact the other side of the enlarged-diameter blade brackets 26, 26, as shown in FIG.
It rotates integrally with the inner cylinder 4.

When a bulb portion is formed after excavating an underground hole 31 having a required depth, as shown in FIG. 8B, the drive shaft 2 is rotated upward by about 90 degrees in the reverse direction (counterclockwise) and upward. When the inner spline 17 is slightly lifted, the inner spline 16 is rotated by contacting the outer splines 16, 16 with which the inner splines 17 are separated, and the cam plate 12 is rotated, and the overhanging portions 14, 14 are moved by the lever portions 19. , 19 are pushed out in the radial direction, whereby the turning bases 25, 25 turn outward in the radial direction of the inner cylindrical body 4 and, while deforming the wire inserted through the through holes 28, 28, expand the blade. 7, 7 is pushed outward in the radial direction.

As a result, the radially enlarged blades 7, 7 bite into the inner wall of the underground hole 42 to generate resistance, and the shaft 2 is still pulled upward as shown in FIGS. With this, the enlarged diameter blades 7 and 7 are in a substantially horizontal position, and the cam plate 1
The two rotation base pressing portions 13, 13 press the rotation bases 25, 25 downward, and the rotation bases 25, 25 stop rotating at the lower plate 22b of the guide body 5. In a state in which the diameter-enlarging blades 7 are substantially orthogonal to the inner cylindrical body 4, the drive shaft 2 is rotated forward again to excavate the diameter-enlarging hole 32. At this time, the rotation is transmitted to the collar body 6 when the swivel stoppers 23 abut against the rotating bases 25.

When the diameter-enlarged hole 32 having the required depth is excavated, the excavation is stopped (see FIG. 9D). Then, as shown in FIG. 1
Is raised and returned into the enlarged diameter hole 32, the rotating base pressing portion 13 and the protruding portion 15 of the cam plate 12 separate from the rotating base 25 as shown in FIG. The body 5 rotates approximately 90 degrees, and the lower plate 22b separates from the lower part of the large-diameter blades 7,7. Therefore, since the enlarged diameter blades 7, 7 do not have a lower stopper and do not hit the swivel screw 8b, they rotate downward about the shaft 27 and hang down to be substantially parallel to the inner cylindrical body 4. Posture.

Thus, when the enlarged diameter blades 7, 7 are suspended, they are housed within the radius of the spiral blades 8a, 8b, so that the drive shaft 2 is moved upward as shown in FIG. When lifted, the excavating head 1 can be pulled up from the enlarged diameter hole 32 into the underground hole 31 by forward rotation, and can be pulled out to the ground as it is.

[0020]

According to the present invention described above, the formation of the bulb portion in the underground hole excavated by the earth auger can be performed in a series of steps without interruption by selectively using the forward rotation and the reverse rotation of the earth auger. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional plan view of a part below a collar body 6 shown in FIG. 1;

FIG. 3 is a partial cross-sectional plan view of the cam plate 12 shown in FIG.

FIG. 4 shows the collar body 6 in a state where the diameter-enlarging blade 7 is rotated upward.
FIG.

FIG. 5 is an operation explanatory view of the cam plate 12 in the case of FIG. 4;

FIG. 6 shows the collar body 6 in a state where the diameter-enlarging blade 7 is rotated downward.
FIG.

7 is an explanatory diagram of the operation of the cam plate 12 in the case of FIG.

8 (A) to 8 (C) show a drilling head 1 according to the present invention.
It is explanatory drawing of the example of excavation construction of the diameter expansion hole 32 using.

9 (D) to 9 (F) show a drilling head 1 according to the present invention.
It is explanatory drawing of the example of excavation construction of the diameter expansion hole 32 using.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Excavation head 2 ... Excavation shaft 3 ... Outer cylinder body 4 ... Inner cylinder body 5 ... Guide body 6 ... Collar body 7 ... Large diameter blade 8a, 8b ... Spiral blade 11 ... Connection block 12 ... Cam plate 13 ... Rotation base pressing part 14 Projection part 15 Projection part 16 Outer spline 17 Inner spline 18 Tube 19 Depression 21 Guide body 22b Lower plate 23 Swivel stopper 25 Rotation base 26 Diameter expansion Blade bracket 27 ... Shaft 28 ... Through hole 29 ... Lever part 31 ... Underground hole 32 ... Large diameter hole

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E21B 10/32 E21B 7/28

Claims (2)

(57) [Claims] An underground hole is excavated by forward rotation by being connected to a lower end portion of a drive shaft such as an earth auger, and a large diameter blade is rotated by reverse rotation and bites into an inner wall of the underground hole while being pulled up by forward rotation. An excavating head that opens and closes, wherein the excavating head is directly or indirectly connected and fixed to a lower end of the drive shaft, and is rotatable within a predetermined angle by being coaxially fitted into the outer cylinder. An inner cylinder body, a guide body comprising a pair of flange portions having upper and lower portions which are fixed to the inner cylinder body in the vicinity of the lower end portion of the outer cylinder body and have a missing circular portion, and the inner cylinder is provided between the flange portions. A collar body rotatably loosely fitted to the body and having the enlarged-diameter blade pivotally mounted in a vertically rotatable manner; and a cam plate connected to and fixed to a lower end of the outer cylindrical body in contact with the flange portion. When,
The cam portion formed on the cam plate is slidably contacted with a projection formed at an end thereof, and the turning base of the large-diameter blade is brought into contact with the cam portion. It comprises a swivel stopper provided on the guide body for transmitting to the collar body, an upright positioning means for the enlarged diameter blade, and spiral blades wound around and fixed to the outer cylinder and the inner cylinder, respectively. A drilling head characterized in that: 2. The standing means for positioning the enlarged diameter blade, wherein the enlarged diameter blade bracket for rotatably supporting the rotating base of the enlarged diameter blade is provided on the collar body, and the enlarged diameter blade is connected to the cylindrical body. In a state of standing substantially in parallel, a through-hole formed by communicating the rotating base and the enlarged-diameter blade bracket, and a wire that is inserted through the through-hole in advance and can be deformed under a predetermined load. The drilling head according to claim 1, wherein the drilling head comprises: