JP6758764B2 - Earth drill - Google Patents

Description

The present invention relates to an earth drill, and more particularly to an earth drill provided with a coil spring that cushions an impact transmitted to a keriba.

With an earth drill in which a kelly bar is rotatably and vertically hung on a wire rope that hangs down from the tip side of a boom that is undulating on the base machine, multiple kelly bar members with different horizontal cross-sectional sizes are stretchably fitted. In addition, a telescopic keriba that is combined in a multi-stage telescopic manner is used.

In such a telescopic kelly bar, when the kelly bar is contracted, it is transmitted to the kelly bar by a cushioning material made of a coil spring interposed between the lower end portion of the innermost kelly bar member and the lower end portion of the adjacent kelly bar member. The impact is mitigated (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2008-106482

However, during excavation work, the Keriba may be overloaded. For example, since it is necessary to close the bottom lid of the excavation bucket after excavating the excavated soil, the keriba is lowered to press the bottom lid of the excavation bucket against the ground. At this time, if the descending speed of the kelly bar is too fast, the coil spring may be in a fully compressed state by receiving a large compressive load from the kelly bar. When such a total compression state is repeated, the coil spring may be deformed or cracked, and in the worst case, it may be damaged.

Therefore, an object of the present invention is to provide an earth drill capable of protecting a coil spring that absorbs an impact transmitted to a keriba with a simple structure and preventing damage.

In order to achieve the above object, the earth drill of the present invention includes a multi-stage kelly bar member that is telescopically fitted, and a wire in which the innermost layer kelly bar member of the multi-stage kelly bar member hangs down from the tip side of the boom. An excavation bucket mounted on the lower end of the innermost layer of the keriva member by being suspended from the rope via a swivel joint and rotationally driving the outermost layer of the keriva member of the plurality of stages of the keriva member by the keriba drive device. In an earth drill that rotates to excavate an excavation target, a fixed spring receiver provided on the outer periphery of the lower end portion of the innermost layer keriba member and an outer periphery of the innermost layer keriba member above the fixed spring receiver. A coil spring that is interposed between the loosely fitted floating spring receiver and the fixed spring receiver and the floating spring receiver, and supports the keriba member adjacent to the innermost keriba member via the floating spring receiver. , It is provided around the coil spring, and when the coil spring is contracted by receiving a compressive load, it is restricted that the coil spring contracts more than a predetermined amount by abutting against the fixed spring receiver and the floating spring receiver. It is characterized by being equipped with a protective cover.

Further, the earth drill of the present invention is characterized in that the protective cover is provided on either the fixed spring receiver or the floating spring receiver, and is formed in a cylindrical shape having a plurality of openings in the peripheral wall. ..

According to the earth drill of the present invention, even if a load that fully compresses the coil spring is generated, the coil spring contracts more than a predetermined amount by contacting the fixed spring receiver and the floating spring receiver. Since it is regulated, it is possible to prevent the coil spring from being fully compressed to cause deformation, cracking, or the like. Further, since the protective cover surrounds the coil spring, even if the coil spring is damaged, it is possible to prevent the fragments of the coil spring from scattering.

Furthermore, since the protective cover has a plurality of openings in the peripheral wall and is formed in a cylindrical shape, the state of the coil spring can be visually confirmed without disassembling, so that the earth and sand adhering to the coil spring can be easily cleaned. , Deterioration of the coil spring can be detected at an early stage, and the maintenance timing can be easily grasped.

It is a side view of the earth drill provided with the telescopic kelly bar which shows the 1st Embodiment example of this invention. It is also a half cross-sectional view of the telescopic Keriva. Similarly, it is a partial cross-sectional view of the main part of the telescopic keriba. It is a partial cross-sectional view of the main part of the telescopic Keriba which shows the 2nd Embodiment example of this invention.

1 to 3 show an example of the first embodiment of the earth drill of the present invention. As shown in FIG. 1, in the base machine 12 of the earth drill 11, the upper swivel body 14 is rotatably provided on the upper part of the lower traveling body 13 provided with the crawler 13a via a swivel bearing. A boom 15 is provided on the front portion of the upper swivel body 14 so as to be undulating, and a foldable gantry 16 is provided on the rear portion of the upper swivel body 14. A plurality of main winding ropes 17 and auxiliary winding ropes 18 which are lifting ropes and undulating ropes 19 for boom undulations are wound around the central portion of the upper swivel body 14 between the boom 15 and the gantry 16 in the width direction. Winches (not shown) are arranged respectively. A counterweight 20 is mounted on the rear end of the upper swing body 14. A driver's seat 14a and an equipment room 14b are provided on the right side of the upper swing body 14, and an engine room (not shown) containing an engine and a hydraulic pump is provided on the left side.

Further, a top sheave 21 on which a main winding rope 17 for lifting and a supplementary winding rope 18 are hung is provided at the upper end of the boom 15, and a top sheave 21 for supporting the keriba drive device 22 is provided at the lower end side of the boom 15. An arm 23 and a plurality of cylinders 24 are attached.

The main winding rope 17 is hung around the top sheave 21 and hangs down from the upper end of the boom 15, and the kelly bar 26 is rotatably and vertically suspended via the swivel joint 25. An excavation bucket 27 is attached to the lower end of the kelly bar 26 that penetrates the rotary drive unit of the kelly bar drive device 22, and the main winding rope 17 is unwound from the winch while rotating the kelly bar 26 with the kelly bar drive device 22 while rotating. The excavation work is performed by the descending excavation bucket 27.

As shown in FIG. 2, the kelly bar 26 includes a first kelly bar member 28 in the innermost layer, a second kelly bar member 29 through which the first kelly bar member 28 is inserted, and a third kelly bar member through which the second kelly bar member 29 is inserted. 30, a telescopic telescopic keriba having a five-layer structure in which the fourth keriba member 31 through which the third keriba member 30 is inserted and the fifth keriba member 32 of the outermost layer through which the fourth keriba member 31 is inserted are combined. It is formed so as to expand and contract according to the excavation depth.

A plurality of engaging ribs (not shown) are provided on the outer peripheral surface of each of the kelly bar members 28 to 32 at equal intervals in the circumferential direction in the axial direction, and other kelly bar members other than the first kelly bar member 28 are provided. Cylindrical guide members 29a to 32a having an engaging groove (not shown) with which the engaging ribs are slidably engaged in the axial direction are provided at the lower ends of the portions 29 to 32, respectively. Further, an engaging groove (not shown) is provided on the inner peripheral surface of the rotation driving unit of the kelly bar driving device 22 so that the engaging rib of the fifth kelly bar member 32 of the outermost layer is slidably engaged in the axial direction. Has been done.

The outer periphery of the upper end portion of the first kelly bar member 28 abuts on the upper surface of the guide member 29a provided below the second kelly bar member 29 so that the first kelly bar member 28 does not come out downward from the second kelly bar member 29. A cylindrical retaining member 34 is provided detachably by a fixing pin 34a, and a cushioning material 35 that is in sliding contact with the inner peripheral surface of the second kelly bar member 29 is provided on the outer periphery of the retaining member 34 by a fixing bolt 35a. It is installed.

Further, on the outer periphery of the upper end portion of each of the kelly bar members 29 to 31 excluding the innermost layer and the outermost layer, cushioning materials 29b to 31b that are in sliding contact with the inner peripheral surfaces of the kelly bar members 30 to 32 adjacent to the outside are fixed bolts 41 to 41. It is detachably provided by 43, and below each of the cushioning materials 29b to 31b, it comes into contact with the guide members 30a to 32a of the kelly bar members 30 to 32 adjacent to the outside to prevent the kelly bar members 29 to 31 from falling off downward. The stoppers 29c to 31c are fixed to each other.

On the other hand, flange members 29d to 31d are detachably provided below the guide members 29a to 31a by a plurality of fixing pins 44 to 46 inserted in the radial direction. The outer diameters of the flange members 29d to 31d are set to be substantially the same as the outer diameter of the guide member 32a of the outermost layer, and are formed so as to overlap each other when the keriva 26 is shortened.

A swivel joint connecting portion 33 having a pin insertion hole 33a is provided at the upper end of the first kelly bar member 28 in order to detachably connect the swivel joint 25 with a connecting pin (not shown), and the first kelly bar member 28 is provided. A bucket connecting portion 36 having a connecting pin insertion hole 36a is provided at the lower end portion of the excavation bucket 27 so as to be detachably connected by a connecting pin (not shown).

A ring-shaped fixed spring receiver 37 projecting in the outer peripheral direction of the first kelly bar member 28 is fixedly provided above the fixed spring receiver 37 at the lower portion of the first kelly bar member 28 and above the bucket connecting portion 36. Is provided with a ring-shaped floating spring receiver 38 that is loosely fitted on the outer periphery of the first kelly bar member 28 and can be brought into contact with the lower surface of the flange member 29d of the second kelly bar member 29.

Between the fixed spring receiver 37 and the floating spring receiver 38, a coil spring 40 having a lower end abutting on the upper surface of the fixed spring receiver 37 and an upper end abutting on the lower surface of the floating spring receiver 38 is formed on the first kelly bar member 28. It is loosely fitted on the outer circumference.

Further, a cylindrical protective cover 39 is fixed to the lower surface of the floating spring receiver 38 by welding. The protective cover 39 has an inner diameter that surrounds the outer circumference of the coil spring 40, and the length (height) in the vertical direction is longer than the length of the coil spring 40 in the fully compressed state, and the coil spring in the no-load state. The length is set shorter than the length of 40, and in the shortened state, when the coil spring 40 is in a normal use state in which the second kelly bar member 29 to the fifth kelly bar member 32 are supported, the upper surface of the fixed spring receiver 37 and the lower end of the protective cover 39 A predetermined gap (A) is formed in the (FIG. 3). Further, a plurality of openings 39a are provided on the peripheral wall of the protective cover 39.

When excavating with the earth drill 11, as shown in FIG. 1, the kelly bar 26 in which the first kelly bar member 28 is suspended from the main winding rope 17 via the swivel joint 25 so as to be able to move up and down and rotate is driven by the kelly bar. The main winding rope 17 is inserted through the rotary drive unit of the device 22 to apply a rotary drive force from the keriva drive device 22 to the fifth keriba member 32, and while rotating the excavation bucket 27 connected to the lower end of the first keriva member 28. Is unwound and the excavation bucket 27 is inserted into the ground to excavate earth and sand by the excavation bucket 27.

The rotational driving force from the kelly bar driving device 22 is transmitted from the fifth kelly bar member 32 to the first kelly bar member 28 via the fourth kelly bar member 31, the third kelly bar member 30, and the second kelly bar member 29, and causes the excavation bucket 27 to move. Rotate. Further, when the first kelly bar member 28 is lowered by unwinding the main winding rope 17, the second kelly bar member 29 to the fourth kelly bar member 31 move downward, so that the kelly bar 26 has a length corresponding to the excavation depth. Is automatically expanded.

When the excavated soil excavated by the excavation bucket 27 is discharged, the main winding rope 17 is rewound to the winch to raise the first kelly bar member 28. When the first kelly bar member 28 is raised, the floating spring receiver 38 abuts on the flange member 29d of the second kelly bar member 29. At this time, the coil spring 40 is compressed and the impact transmitted to the second kelly bar member 29 is alleviated, and the second kelly bar member 29 is supported by the coil spring 40 via the idle spring receiver 38.

Hereinafter, similarly, when the first kelly bar member 28 is raised, the flange member 29d is attached to the flange member 30d, the flange member 30d is attached to the flange member 31d, and the flange member 31d is attached to the lower end of the fifth kelly bar member 32. The impact is relaxed by the spring 40 and hits, the keriba 26 is shortened, and the excavation bucket 27 is pulled up from the excavation hole to the ground.

As described above, the coil spring 40 takes into consideration an appropriate amount of deflection so as not to be completely compressed with a compressive force sufficient to alleviate the impact caused by the collision between the flanges when raising the first kelly bar member 28. Is designed.

On the other hand, after opening the bottom lid of the excavation bucket 27 and discharging the excavated soil in the bucket, the first keriba member 28 is lowered with the bottom lid pressed against the ground to lower the excavation bucket 27, and the bottom lid is lowered. Perform a close operation. At this time, when the first kelly bar member 28 is rapidly lowered and the bottom lid is closed in a state where the excavation bucket 27 falls, the coil spring 40 is supported by the second kelly bar via the floating spring receiver 38. The total weight of the members 29 to the fourth kelly bar member 31 may act abruptly, and a load such that the coil spring 40 may be fully compressed may act on the idle spring receiver 38.

When such a large load acts on the coil spring 40, the lower end of the protective cover 39 abuts on the upper surface of the fixed spring receiver 37 to receive the compressive load of the coil spring 40 before the coil spring 40 is fully compressed. It is possible to prevent the spring 40 from being completely compressed. As a result, the coil spring 40 is restricted from contracting beyond a predetermined amount and is not fully compressed. Therefore, fatigue of the coil spring 40 can be reduced, and deformation, cracking, etc. of the coil spring 40 can be suppressed. ..

Further, since the protective cover 39 surrounds the outer circumference of the coil spring 40, even if the coil spring 40 is damaged, it is possible to prevent the fragments of the coil spring 40 from scattering. Further, since the protective cover 39 is provided on the lower surface of the floating spring receiver 38 and a gap (A) is formed between the lower end of the protective cover 39 and the upper surface of the fixed spring receiver 37, earth and sand or water is formed in the protective cover 39. Can be prevented from accumulating. In addition, since a plurality of openings 39a are provided on the peripheral wall of the protective cover 39, the state of the coil spring 40 can be visually confirmed from the outside without disassembling the keriba 26, so that deterioration of the coil spring 40 can be detected at an early stage. It is possible to easily grasp the maintenance time.

FIG. 4 is a partial cross-sectional view of a main part of the telescopic keriba showing an example of the second embodiment of the present invention. In the following description, the same components as those shown in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
In this embodiment, the protective cover 51 formed in the same manner as in the first embodiment is placed on the upper surface of the fixed spring receiver 37 so as to surround the coil spring 40, and is a floating spring in a normal use state. A predetermined gap (B) is formed between the lower surface of the receiver 38 and the upper end of the protective cover 51.

As a result, when a large compressive load is applied to the coil spring 40, the lower surface of the idle spring receiver 38 abuts on the upper end of the protective cover 51 to receive the compressive load acting on the coil spring 40. It is possible to prevent 40 from being in a fully compressed state. Further, even if the coil spring 40 is damaged, it is possible to prevent the fragments of the coil spring 40 from scattering, and the state of the coil spring 40 can be visually confirmed from the outside by the plurality of openings 51a provided in the peripheral wall.

Further, since the protective cover 51 is placed on the upper surface of the fixed spring receiver 37, the trouble of welding can be saved, and water or earth and sand can be removed from the inside of the protective cover 51 by slightly lifting the protective cover 51. Can be discharged.

11 ... Earth drill, 12 ... Base machine, 13 ... Lower running body, 13a ... Crawler, 14 ... Upper swivel body, 14a ... Driver's seat, 14b ... Equipment room, 15 ... Boom, 16 ... Gantry, 17 ... Main winding rope, 18 ... Complementary winding rope, 19 ... Undulating rope, 20 ... Counter weight, 21 ... Top sheave, 22 ... Kelly bar drive, 23 ... Arm, 24 ... Cylinder, 25 ... Swivel joint, 26 ... Kelly bar, 27 ... Drilling bucket, 28 ... 1st kelly bar member, 29 ... 2nd kelly bar member, 29a ... guide member, 29b ... cushioning material, 29c ... stopper, 29d ... flange member, 30 ... 3rd kelly bar member, 30a ... guide member, 30b ... cushioning material, 30c ... Stopper, 30d ... Flange member, 31 ... 4th Kelly bar member, 31a ... Guide member, 31b ... Buffer material, 31c ... Stopper, 31d ... Flange member, 32 ... 5th Kelly bar member, 32a ... Guide member, 33 ... Swivel joint Connecting part, 33a ... Pin insertion hole, 34 ... Retaining member, 34a ... Fixing pin, 35 ... Buffer material, 35a ... Fixing bolt, 36 ... Bucket connecting part, 36a ... Connecting pin insertion hole, 37 ... Fixed spring receiver, 38 ... Floating spring receiver, 39 ... protective cover, 39a ... opening, 40 ... coil spring, 41, 42, 43 ... fixing bolt, 44, 45, 46 ... fixing pin, 51 ... protective cover, 51a ... opening

Claims (4)

A multi-stage kelly bar member that is telescopically fitted is provided, and the innermost kelly bar member of the multi-stage kelly bar member is suspended from a wire rope hanging from the tip side of the boom via a swivel joint, and the multi-stage kelly bar member is suspended. In the earth drill for excavating an excavation target, the excavation bucket attached to the lower end of the innermost layer kelly spring member is rotated by the rotation drive of the outermost layer kelly spring member of the kelly spring member. A fixed spring receiver provided on the outer periphery of the lower end portion of the innermost layer of the keriba member, a floating spring receiver above the fixed spring receiver and loosely fitted on the outer periphery of the innermost layer of the keriba member, and the fixed spring receiver. A coil spring is provided between the floating spring receiver and supports the kelly bar member adjacent to the innermost kelly bar member via the floating spring receiver, and the coil spring is provided around the coil spring. An earth drill provided with a protective cover that regulates the coil spring from contracting more than a predetermined amount by abutting against the fixed spring receiver and the floating spring receiver when contracting by receiving a compressive load. .. The earth drill according to claim 1, wherein the protective cover is formed in a cylindrical shape having a plurality of openings in the peripheral wall. The earth drill according to claim 1 or 2, wherein the protective cover is fixed to the lower surface of the floating spring receiver. The earth drill according to claim 1 or 2, wherein the protective cover is placed on the upper surface of the fixed spring receiver.

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