JP2023008062A - Bucket device for earth drill - Google Patents

Abstract

To dispense with external force such as hydraulic pressure for opening and closing a bucket, and to exhibit a large gripping force at the same time when the bucket starts closing operation.SOLUTION: The present invention comprises a casing 2, a right and left pair of buckets 3 that can be opened and closed inside the casing 2, and a connecting member 6 that moves vertically integrally with the kelly bar. A right and left pair of tapered grooves 22, 22 are formed in the connecting member 6 such that the separation distance therebetween gradually increases downward. On both sides of the bucket 3, a set of two arms 9 is arranged, an upper end 9a of which is rotatably supported at the upper position of a bucket device 1. A lower end 9b of one arm 9A is rotatably connected to one bucket 3. A lower end 9c of the other arm 9B is rotatably connected to the other bucket 3. A pair of two arms 9A and 9B are connected to each other by a slide shaft 10 inserted through the tapered grooves 22 of the connecting member 6 at the midpoint thereof.SELECTED DRAWING: Figure 2

Description

The present invention relates to an earth drill bucket device that is attached to the lower end of a kelly bar of an earth drill machine to excavate boulders, boulders, and the like.

Conventionally, the earth drilling method, which is one of the cast-in-place concrete pile construction methods, attaches a drilling bucket to the lower end of a rotating shaft called a kelly bar of an earth drilling machine, and presses downward while rotating the drilling bucket to create a cone. While excavating the bottom of the vertical hole with a cutter provided on the bottom lid, the excavated soil is taken into the bucket from the opening provided in the bottom lid. This is a construction method in which pile holes are formed by repeating the procedure of soiling. This earth drilling method is widely used for foundation work of high-rise buildings, condominiums, etc., because it has features such as faster construction speed and lower construction cost than other construction methods.

In this earth drilling method, since the drilling bucket cannot take in boulders such as boulders and boulders from the opening of the bottom cover, when excavating such a boulder zone, a grab bucket is used instead of the drilling bucket. After installation, the grab bucket grabs the excavated material and discharges it to the ground.

As such a bucket device for an earth drill, Patent Document 1 below discloses a construction in which a hydraulic cylinder is extended by pulling up a kelly bar in a drilling tool provided with an openable bucket to close the openable bucket. .

Further, in Patent Document 2 below, a cylindrical casing portion, a pair of shell portions arranged inside the casing portion and having ends of pins serving as fulcrums for opening and closing supported by the casing portion, a connecting portion connected to a lower end of a rotationally driven kelly bar; a guide portion fixed to the casing portion above the shell portion and accommodating the connecting portion so as to be vertically movable; The pair of shell portions is opened when the portion is positioned below the guide portion, and the pair of shell portions is closed when the connection portion is positioned above the guide portion. A bucket device comprising: an arm portion that connects the shell portion; and a lock portion that is provided at the lower portion of the connecting portion that can switch between projecting and housing the guide portion to the side depending on the rotation direction of the connecting portion. is disclosed.

Furthermore, the present applicant also discloses a cylindrical casing with an open bottom surface, an open position in which the casing is rotatably supported inside the casing, and the bottom surface side of the casing is open. a pair of left and right buckets that can be opened and closed to a closed position that closes the lower surface side of a casing; , a pair of left and right tapered grooves are formed along the substantially vertical direction, which are spaced apart from each other on the side where the bucket is arranged, and are formed such that the separation distance gradually increases toward the lower side. One end of the connecting member and the bucket are movably and rotatably supported along the tapered groove, the other end is rotatably supported by the bucket, and are rotatable relative to each other at the intersection. proposed a bucket apparatus for an earth drill, which is connected by an X-shaped link member connected to the carriage, and is constructed such that the bucket is moved from an open position to a closed position by pulling up the kelly bar.

Japanese Patent No. 3818519 JP 2015-224461 A JP 2020-7767 A

However, in the case of the excavating tool described in Patent Document 1, since a hydraulic cylinder is used to open and close the openable bucket, there is a problem that handling of the hydraulic hose is troublesome during excavation work. In addition, when the hydraulic hose is cut, hydraulic oil is scattered, and it takes time and effort to dispose of it, and the surrounding environment is polluted. Furthermore, using a hydraulic cylinder complicates the structure and requires maintenance.

In the case of the bucket device described in Patent Document 2, in order to close the pair of shell portions, the kelly bar is pulled up, the connecting portion connected to the lower end of the kelly bar is raised relative to the guide portion, and the connecting portion is lifted. By vertically raising the arm portion connected to the portion, the shell portion connected to the lower end of the arm portion rotates around the pin serving as the fulcrum for opening and closing. At this time, the arm portion transmits the force when the kelly bar is pulled up as it is to the shell portion as a vertical force. It is designed to move. Therefore, when the shell portion is closed, the gripping force is weak, and there is a risk that the boulder cannot be reliably gripped, and there is a risk that the amount of gripping at one time will be reduced.

On the other hand, in the case of the bucket device disclosed in Patent Document 3, when the kelly bar is pulled up, the connecting member moves upward together with the kelly bar, and one end of the X-shaped link member is formed into a tapered groove. Since the bucket can be moved from the open position to the closed position through the link mechanism by moving along the It has the advantage of being able to generate force, to be able to reliably grab boulders, etc., and to be able to stably obtain a single grasping amount. However, this toggle mechanism is activated in the middle of the process from when the bucket starts to close until it is completely closed. was rare.

Therefore, the main object of the present invention is to eliminate the need for external force such as hydraulic pressure for opening and closing the bucket, to stably obtain a gripping amount for one bucket, and to exhibit a large gripping force at the same time as the bucket starts closing operation. To provide a bucket device for an earth drill which is

In order to solve the above problems, the present invention according to claim 1 is a bucket device for an earth drill that is detachably attached to the lower end of a kelly bar,
A cylindrical casing whose lower surface is open, and which is rotatably supported by the casing inside the casing, and which opens and closes between an open position in which the lower surface side of the casing is open and a closed position in which the lower surface side of the casing is closed. a pair of left and right buckets, and a connecting member provided inside the casing and moving vertically integrally with the kelly bar,
The connecting member is formed with a pair of left and right tapered grooves which are separated from each other on the side where the pair of left and right buckets are arranged, and which are formed so that the distance between the left and right buckets gradually increases toward the lower side. is,
On both sides of the bucket, a pair of arms whose upper ends are rotatably supported at the upper position of the bucket device are arranged, and the lower ends of the arms on one side rotate to one side of the bucket. The lower end of the arm on the other side is rotatably connected to the other side of the bucket, and the pair of arms at their midpoints is inserted through the tapered groove of the connecting member. The corresponding arms are connected by the slide shaft,
A bucket for an earth drill, wherein the bucket is moved from an open position to a closed position by pulling up the kelly bar to raise the connecting member and moving the slide shafts in a separation direction. An apparatus is provided.

The invention according to claim 1 is an earth drill bucket device that is used by being attached to the lower end of a kelly bar in place of a drilling bucket when excavating a boulder zone such as boulders and boulders with an earth drill machine. , a left and right pair of buckets for gripping boulders rotatably supported by the casing inside the casing, and a connecting member that moves vertically integrally with the kelly bar. Tapered grooves are formed in the connecting member so as to separate them from side to side in a V shape when viewed from the front.

A pair of arms are arranged on each side of the bucket. A set of two arms are rotatably supported at their upper ends at an upper position of the bucket device, and the lower end of one arm is rotatably connected to one side of the bucket, and the other arm is rotatably connected to one side of the bucket. The lower ends of the arms are rotatably connected to the other side of the bucket, and the pairs of arms are connected at their midpoints by a slide shaft inserted through the tapered groove of the connecting member. ing.

Therefore, the bucket is moved from the open position to the closed position by pulling up the kelly bar to raise the connecting member and move the slide shafts in the separating direction.

As described above, the earth drill bucket device does not use an external force such as hydraulic pressure as a drive source for opening and closing the bucket. It is possible to save time and effort such as maintenance. Further, when the kelly bar is pulled up, the connecting member rises and the slide shafts move away from each other, so that the pair of arms spreads and the bucket moves from the open position to the closed position. You will be able to move. The upper end of the arm serves as a fulcrum, the point of connection with the slide shaft serves as a power point, and the point of connection with the bucket serves as a point of action. At the same time as starting the movement, it becomes possible to demonstrate a large gripping force. Therefore, a strong cutting edge force can be generated when the bucket is closed, so that the boulder or the like can be reliably gripped, and the amount of gripping per operation can be stably obtained.

As the present invention according to claim 2, in the pair of arms, the distance L1 from the rotation shaft at the upper end of the arm to the connecting portion with the slide shaft and the bucket at the lower end of the arm from the connecting portion with the slide shaft A bucket device for an earth drill according to claim 1, wherein the ratio of the distance L2 to the connecting portion is L1/L2=2.0 to 3.0.

In the second aspect of the invention, according to the third lever principle, it is possible to obtain a large acting force by increasing the distance from the fulcrum to the point of force. Therefore, in the pair of arms, the distance L1 from the rotation shaft at the upper end of the arm to the connection with the slide shaft, and the distance from the connection with the slide shaft to the connection with the bucket at the lower end of the arm. By setting the ratio of L2 to L1/L2=2.0 to 3.0, it is possible to generate a large gripping force at the same time as the bucket starts opening and closing operations.

According to a third aspect of the present invention, the bucket is provided with bearings or shafts on the outer surfaces of both sides of the bucket, and these bearings or shafts are engaged with the shafts or bearings provided on the inner surface of the casing. The earth drill bucket device according to any one of claims 1 and 2 is provided so as to be openable and closable.

In the third aspect of the invention, in the bucket rotation support structure, bearings or shafts are provided on the outer surface of both sides of the bucket, and these bearings or shafts are provided on the inner surface of the casing. It has a structure supported so as to be openable and closable by engagement. By arranging the rotation support portion of the bucket outside the bucket, it is possible to increase the volume of the bucket.

According to a fourth aspect of the present invention, there is provided a cylindrical guide cover provided on the upper surface of the casing; a joint shaft rotatable around,
A stopper projecting from the peripheral surface of the joint shaft is provided, and an engagement groove with which the stopper can be engaged is provided in the guide cover along the vertical direction, and the stopper is provided at the lower end of the engagement groove. A bucket device for an earth drill according to any one of claims 1 to 3, further comprising a locking portion that locks and prevents axial movement of the joint shaft.

In the invention according to claim 4, in order to hold the bucket in the open position during excavation by the present bucket device, a stopper is provided on the peripheral surface of the joint shaft, and the stopper is a lock portion formed at the lower end of the engagement groove. so that it can be locked to

As described in detail above, according to the present invention, external force such as hydraulic pressure is not required for opening and closing the bucket, the amount of gripping per bucket can be stably obtained, and at the same time, a large gripping force is exhibited at the same time as the bucket starts closing operation. A bucket device for an earth drill can be obtained.

1(A) is a side view and (B) is a front view showing an earth drill bucket device 1. FIG. 1 is a vertical cross-sectional view of an earth drill bucket device 1 (in a bucket open state); FIG. 1 is a vertical cross-sectional view of an earth drill bucket device 1 (bucket closed state). FIG. FIG. 2 is a horizontal cross-sectional view of bucket 3 (a view taken along line IV-IV in FIG. 1); FIG. 2 is a horizontal cross-sectional view of the guide cover 4 (taken along the line VV in FIG. 1); 1 shows a casing 2, (A) is a side view, (B) is a view taken along line B-B, and (C) is a view taken along line C-C. 3 is a perspective view showing an assembled state of an arm 9, a bucket 3 and a slide shaft 10; FIG. FIG. 3(A) is a front view and FIG. 3(B) is a front view showing an assembled state of an arm 9, a slide shaft 10 and a connecting member 6; FIG. 11 is an explanatory diagram (part 1) of the force generated when the bucket is closed; FIG. 2 is an explanatory diagram (part 2) of the force generated when the bucket is closed;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

An earth drill bucket device 1 according to the present invention is detachably attached to the lower end of a kelly bar of an earth drill machine in place of a drilling bucket when excavating boulders, boulders, or other boulders that cannot be excavated with a drilling bucket.

As shown in FIG. 1 , the earth drill bucket device 1 has a cylindrical casing 2 with an open bottom surface, and is rotatably supported by the casing 2 inside the casing 2 . a left and right pair of buckets 3 (3A, 3B) that can be opened and closed between an open position (state shown in FIG. 2) in which the side is opened and a closed position (state shown in FIG. 3) in which the lower surface side of the casing 2 is closed; A cylindrical guide cover 4 which protrudes and is fixed to the upper surface of the casing 2 and which is provided coaxially with the casing 2 and whose upper and lower surfaces are open; a joint shaft 5 which is inserted into the casing 2 from the outside and slides inside the guide cover 4 to be axially movable and rotatable about the axis; , a connecting member 6 attached to the lower end of the joint shaft 5 and moving up and down integrally with the kelly bar; A pair of arms 9 are provided.

The casing 2 has a substantially cylindrical outer shape with an open lower surface, an opening 2a is formed in the central portion of the upper surface, and a plurality of bits 7, 7, . . . are provided around the lower end.

6, the casing 2 has a structure in which an upper casing 2A and a lower casing 2B are vertically connected.

The upper casing 2A has an opening 2a formed in the central portion of the upper surface thereof. Further, as shown in FIG. 6(B), a rectangular opening 2b is formed on the lower surface, and a slide guide 11 for the connecting member 6 is provided. The sliding guide 11 is provided with upright flanges 11A and 11B on two opposite sides of the opening 2b, respectively. It is designed to move in the direction

The lower casing 2B has a plurality of bits 7, 7, . In the peripheral surface of the lower casing 2B, openings 8, 8 penetrating inside and outside the casing are formed on the left and right sides, respectively, with a dimension slightly larger than the dimension along the casing peripheral surface of the buckets 3A, 3B in the open position. there is As shown in FIG. 4, the opening 8 is formed in such a size that the outer peripheral portion of the bucket 3 in the open position can be fitted with a gap in the outer periphery. As shown in FIG. 4, the inner surface of the lower casing 2B is provided with shafts 12a, 12a for rotatably supporting the buckets 3A, 3B on the left and right sides, respectively.

As shown in FIG. 4, the bucket 3 has an arc-shaped cross section, and bearings 3a, 3a provided on the outer surfaces of both sides are fitted to the shafts 12a, 12a to rotate the shafts. It is centrally supported so that it can be opened and closed between an open position and a closed position. In the open position shown in FIG. 2, they are arranged to fit into the opening 8 of the lower casing 2B, and in the closed position shown in FIG. and flat plate-like side portions 3D connected to both sides of the bucket body portion 3C. The bearings 3a, 3a are provided on the side portion 3D.

At the open position of the bucket 3 shown in FIG. 2, the ground is excavated by the bits 7, 7, . . . Thus, earth and sand that have entered the casing 2 are picked up by the portions of the left and right buckets 3A, 3B covered with the bucket main body portions 3C and the side surface portions 3D.

A connecting plate 3E is continuously formed on the side surface portion 3D beyond the bucket rotating shaft to which a lower end 9b (9c) of an arm 9 for rotating the bucket 3, which will be described later, is connected. The connecting plate 3E is formed so as to protrude substantially upward when the bucket 3 is in the open position.

On the other hand, the guide cover 4 is formed in a cylindrical shape with open upper and lower surfaces, and is fixed to the upper surface of the casing 2 with the opening of the lower surface communicating with the opening 2a provided in the center of the upper surface of the casing 2. It is This structure allows the inside of the guide cover 4 to communicate with the inside of the casing 2 .

As shown in FIG. 1(B), the peripheral surface of the guide cover 4 is provided with an engagement groove 14 which can be engaged with a stopper 18 protruding from the peripheral surface of the joint shaft 5, which will be described in detail later. are set along. A locking portion 15 is formed at the lower end of the engaging groove 14 to engage with the stopper 18 to prevent the joint shaft 5 from moving in the axial direction. The locking portion 15 is a portion wider than the engaging groove 14 formed at the lower end portion of the engaging groove 14, and when the kelly bar rotates in the rotational direction (R direction) during excavation, the stopper 18 is locked. It is for engaging and making it impossible to move up and down.

A joint shaft 5 having a circular cross section is inserted into the guide cover 4 so as to be vertically slidable. At the upper end of the joint shaft 5, there is formed a connecting portion 17 in the shape of a rectangular tube. By engaging this connecting portion 17 with the lower end of the kelly bar and inserting the pin member into the pin hole 17a, the earth drill can be operated. The bucket device 1 is attached to a kelly bar, and the joint shaft 5 can rotate and move up and down integrally with the kelly bar.

A stopper 18 protruding outward is provided on the peripheral surface of the joint shaft 5 . As shown in FIG. 5, the stopper 18 is composed of a shaft member having a substantially rectangular cross section that penetrates the cylindrical joint shaft 5 in the diameter direction. It is fixed in a state in which both ends protrude outward from the portion.

As shown in FIG. 2, the lower end of the joint shaft 5 is formed with a concave groove 5a extending along the entire circumference. By being connected by the structure, the rotation of the joint shaft 5 is not transmitted to the connecting member 6, and only the vertical movement can be transmitted.

The connecting member 6 is attached to the lower end of the joint shaft 5 and has an annular member 19 having an inverted L-shaped cross section on its upper surface for connection with the joint shaft 5 . The annular member 19 is connected to the connecting member 6 by bolts 20 provided at intervals in the circumferential direction in a state in which the projecting portion 19a projecting inward in an inverted L shape is fitted in the concave groove 5a of the joint shaft 5. affixed to the top of the With such a connecting structure, the joint shaft 5 and the connecting member 6 can rotate relatively, but cannot move relative to each other in the vertical direction. Therefore, the rotation of the joint shaft 5 is absorbed by the connecting portion and is not transmitted to the connecting member 6 , and only the vertical movement of the joint shaft 5 can be transmitted to the connecting member 6 .

The connecting member 6 is formed in the shape of a hollow box which is substantially rectangular parallelepiped or cubic, and has a structure in which at least the upper surface and the four peripheral surfaces are covered with plate materials. Specifically, the upper surface plate 21a, the left and right side plates 21c, 21c facing the side where the buckets 3A, 3B are arranged, and the front and rear side plates 21b, 21b facing the side perpendicular to the left and right side plates 21c, 21c. It is composed of

In FIG. 2, the front and rear side plates 21b, 21b, which serve as the front, are separated from each other on the side where the pair of left and right buckets 3A, 3B are arranged, and the separation distance gradually increases downward. A left and right pair of tapered grooves 22, 22 are formed in a V shape when viewed from the front. The tapered groove 22 is an opening penetrating through the front and back side plates 21b, 21b, and is formed by an oblique linear long hole. The tapered grooves 22, 22 are formed symmetrically with respect to the center line L in the axial direction of the kelly bar, and are formed at the same positions on the front and rear side plates 21b, 21b. Although the inclination angle α (see FIG. 9) of the tapered groove 22 with respect to the center line of the kelly bar is arbitrary, it is preferably 10 to 45°, preferably 20 to 30°.

On both sides of the buckets 3A and 3B, that is, on both sides where the opening/closing shafts of the buckets 3A and 3B are arranged, a set of two buckets is supported at an upper position of the bucket device 1 so that the upper end 9a is rotatable. An arm 9 is arranged, a lower end 9b of one arm 9A is rotatably connected to one side of the bucket 3A, and a lower end 9c of the other arm 9B is rotatable to the other side of the bucket 3B. The pairs of arms 9 are movably connected, and the corresponding arms 9A, 9A (9B, 9B) are connected to each other by a slide shaft 10 inserted through the tapered groove 22 of the connecting member 6 at the midpoint thereof. It is

That is, the vertical movement of the joint shaft 5 is transmitted to the connecting member 6, and the moving force of the connecting member 6 is transmitted to the bucket 3 to serve as the opening/closing force of the bucket 3. are provided with a pair of arms 9 for connecting the connecting member 6 and the bucket 3 to each other.

As shown in FIGS. 7 and 8, the pair of arms 9 consists of one side arm 9A and the other side arm 9B. It is rotatably supported. Although the upper end 9a is coaxially supported in the illustrated example, these may be supported separately at adjacent positions.

The one-side arm 9A is oriented substantially vertically (slightly inclined outward), and its lower end 9b is rotatably connected to the upper end of the connecting plate 3E of the bucket 3A. The other arm 9B is also oriented substantially vertically (slightly inclined outward), and its lower end 9c is rotatably connected to the upper end of the connecting plate 3E of the bucket 3B.

The pairs of arms 9 are connected to each other by a slide shaft 10 inserted through a tapered groove 22 of the connecting member 6 at the midpoint thereof.

In this case, in the arm 9, as shown in FIG. 8, the distance L1 from the rotation axis of the arm upper end 9a to the connecting portion with the slide shaft 10 and the distance L1 from the connecting portion with the slide shaft 10 to the lower arm end 9b. The ratio of (9c) to the distance L2 to the connecting portion with the bucket 3 is preferably L1/L2=2.0 to 3.0. Based on the principle of leverage, by setting the distance (L1) from the fulcrum to the point of action as large as possible relative to the distance (L2) from the point of action to the force point, a large gripping force is generated at the same time when the bucket 3 starts opening and closing. it becomes possible to

Here, the gripping forces acting on the buckets 3A and 3B are calculated based on FIGS. 9 and 10. FIG.

The left and right pair of tapered grooves 22, 22 of the connecting member 6 form an isosceles triangle to form a wedge shape, and the principle of the wedge is established. is F, the thrust load F1 when the distance between the slide shafts 10, 10 connecting the pair of arms 9A, 9B increases can be calculated from F1≈2F sin θ. Here, θ is the angle between the vertical line and the tapered groove 22 .

The arms 9A and 9B establish a third lever principle between the upper end 9a (fulcrum), the slide shaft 10 (action point), and the lower end 9b (9c) (force point). Therefore, as shown in FIG. 10, the thrust load F2 at the lower ends 9b (9c) of the arms 9A and 9B is F2≈L1×F1/(L1+L2) according to the principle of the third lever. From this formula, it can be seen that a large thrust load F2 can be obtained when L1 is relatively long. The thrust load F2 at the lower ends 9b (9c) of the arms 9A and 9B is a force that rotates the buckets 3A and 3B about the rotary shafts of the buckets 3A and 3B. The force varies depending on the pinched part, but it is weakest at the tip and becomes stronger as it gets closer to the rotation axis. The gripping force F3 is F3≈F2×L3÷L4.

When the joint shaft 5 moves upward, the separation distance between the slide shafts 10, 10 increases, so that the buckets 3A, 3B are closed. The closing force is F, which is the total weight of the apparatus minus the weight of the joint shaft 5, the kelly bar connecting portion 17, and the connecting member 6, and the gripping force F3 is F3≈L1×2F sin θ×L3÷( L1+L2)/L4 can be calculated.

[Drilling method]
Next, a drilling method using the earth drill bucket device 1 will be described. The earth drill bucket device 1 is attached to the lower end of the kelly bar, the joint shaft 5 is moved to the lowest position, and the kelly bar is rotated in the excavation direction (R direction in FIG. 1) with the stopper 18 locked to the lock portion 15. The ground is excavated while boulders, boulders, etc. are accommodated in the casing 2 by a plurality of bits 7, 7, . . . provided at the lower end of the casing 2.

When the excavated boulders, boulders, and the like accumulate in the casing 2, the kelly bar is rotated in a direction opposite to the excavation direction (R direction) to release the locked state in which the stopper 18 is engaged with the lock portion 15, and the kelly bar is removed. move upwards. At this time, the joint shaft 5 rotates together with the rotation of the kelly bar in the direction opposite to the digging direction, but the rotational movement of the connecting member 6 attached to the lower end of the joint shaft 5 is absorbed at these connecting portions. Therefore, only vertical movement occurs without rotation.

When the kelly bar is moved upward, the joint shaft 5 and the connecting member 6 are moved by the frictional resistance between the peripheral surface of the casing 2 and the inner surface of the borehole, and the weight of the casing 2, the bucket 3, the guide cover 4, the arm 9, and the like. only moves upward relative to the casing 2, and the casing 2 and the like try to stay in place. Since the slide shaft 10 moves relatively downward along the tapered groove 22 as the connecting member 6 moves upward, each of the pair of arms 9A and 9B rotates outward. That is, the arms 9A and 9B move so as to increase the separation distance. When the arms 9A and 9B rotate outward, an outward thrust load F2 acts on the arm lower end 9b (9c), which is the connection point between the arms 9A and 9B and the connection plate 3E of the buckets 3A and 3B. The buckets 3A and 3B are closed while a gripping force F3 is generated in the buckets 3A and 3B by the force of the load F2. Stable quantity will be obtained.

In this way, when the joint shaft 5 is lifted relative to the casing 2 and the buckets 3, 3 are closed, the kelly bars are further lifted, whereby the entire earth drill bucket device 1 can be lifted. The earth drill bucket device 1 lifted up on the ground is placed in a predetermined area of the site, and the joint shaft 5 and the connecting member 6 are moved downward relative to the casing 2 by moving the kelly bar downward. , the buckets 3, 3 are opened, and the excavated soil held by the buckets 3, 3 is discharged to the outside.

Since the earth drill bucket device 1 having the above configuration does not use an external force such as hydraulic pressure or wires as a drive source for opening and closing the bucket 3, there is no need to handle hydraulic hoses, wires, or the like, which hinders excavation work. It does not cause In addition, since it does not have a hydraulic cylinder, the structure can be simplified and maintenance work can be saved.

DESCRIPTION OF SYMBOLS 1... Bucket apparatus for earth drills, 2... Casing, 3 (3A/3B)... Bucket, 4... Guide cover, 5... Joint shaft, 6... Connecting member, 7... Bit, 8... Opening, 9 (9A/9B) ) Arm 9a Upper end 9b (9c) Lower end 10 Slide shaft 11 Sliding guide 11A and 11B Upright flange 14 Engagement groove 15 Lock portion 18 Stopper 19 Annular member, 20...bolt, 22...tapered groove

Claims (4)

A bucket device for an earth drill detachably attached to the lower end of a kelly bar,
A cylindrical casing whose lower surface is open, and which is rotatably supported by the casing inside the casing, and which opens and closes between an open position in which the lower surface side of the casing is open and a closed position in which the lower surface side of the casing is closed. a pair of left and right buckets, and a connecting member provided inside the casing and moving vertically integrally with the kelly bar,
The connecting member is formed with a pair of left and right tapered grooves which are separated from each other on the side where the pair of left and right buckets are arranged, and which are formed so that the distance between the left and right buckets gradually increases toward the lower side. is,
On both sides of the bucket, a pair of arms whose upper ends are rotatably supported at the upper position of the bucket device are arranged, and the lower ends of the arms on one side rotate to one side of the bucket. The lower end of the arm on the other side is rotatably connected to the other side of the bucket, and the pair of arms at their midpoints is inserted through the tapered groove of the connecting member. The corresponding arms are connected by the slide shaft,
A bucket for an earth drill, wherein the bucket is moved from an open position to a closed position by pulling up the kelly bar to raise the connecting member and moving the slide shafts in a separation direction. Device. In the set of two arms, a distance L1 from the rotation shaft at the upper end of the arm to the connection with the slide shaft, and a distance L2 from the connection with the slide shaft to the connection with the bucket at the lower end of the arm. The bucket device for an earth drill according to claim 1, wherein the ratio of L1/L2 is set to 2.0 to 3.0. The bucket is provided with bearings or shafts on the outer surfaces of both sides of the bucket, and is supported so that it can be opened and closed by engaging the bearings or shafts with the shafts or bearings provided on the inner surface of the casing. 3. A bucket device for an earth drill according to any one of Items 1 and 2. A cylindrical guide cover provided on the upper surface of the casing, and a joint fixed to the lower end of the keliver and sliding inside the guide cover so as to be movable in the axial direction and rotatable around the axis. a shaft and
A stopper projecting from the peripheral surface of the joint shaft is provided, and an engagement groove with which the stopper can be engaged is provided in the guide cover along the vertical direction, and the stopper is provided at the lower end of the engagement groove. The bucket device for an earth drill according to any one of claims 1 to 3, further comprising a locking portion that locks to prevent axial movement of the joint shaft.

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