Kelly-bar and earth drilling machine

Abstract

To achieve miniaturization while reducing the noise of a kelly-bar.SOLUTION: A kelly bar (140) including an outer tubular member (141a) located on an outermost side, and a plurality of inner tubular members (141b to 141e) located inside the outer tubular member and movable in an axial direction of the outer tubular member, At least one of the plurality of inner tubular members includes, on an outer periphery thereof, a buffer member (170) including a plurality of buffer pieces (170a to 170d), and a restriction portion (145b, 145d) configured to restrict movement of the buffer member in the axial direction, and the buffer member has a first surface (180c) having a radius larger than that of the restriction portion, and a second surface (181c) having a radius smaller than that of the first surface.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a kelly bar and an earth drill equipped with the same. [Background technology]

[0002] As background art in this technical field, for example, Patent Document 1 discloses a configuration in which "multiple divided kelly bars with different horizontal cross-sectional sizes are fitted together so as to be prevented from rotating relative to each other and to be able to move up and down relatively, two ring-shaped plates are welded to the upper end of at least one of the divided kelly bars other than the outermost divided kelly bar with a gap between them, and a buffer material is fitted between the two ring-shaped plates so that its outer periphery protrudes beyond the outer periphery of the ring-shaped plates and fixed with bolts." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-106482 Summary of the Invention [Problem to be solved by the invention]

[0004] The kelly bar described in Patent Document 1 is constructed to prevent noise caused by collisions between the pipes of the kelly bar using shock absorbers, but because the shock absorbers are fixed in place with bolts, space is required to house them, which results in larger gaps between the pipes of the kelly bar, making it difficult to miniaturize the kelly bar.

[0005] Therefore, a main object of the present invention is to enable miniaturization while reducing the noise of the kelly bar. [Means for solving the problem]

[0006] In order to achieve the above object, a representative aspect of the present invention is a kelly bar including an outer cylindrical member located at the outermost position, and a plurality of inner cylindrical members located inside the outer cylindrical member and movable in the axial direction of the outer cylindrical member, wherein at least one of the plurality of inner cylindrical members is provided on its outer periphery with a buffer material consisting of a plurality of buffer pieces, and a restricting portion that restricts movement of the buffer material in the axial direction, and the buffer material has a first surface having a diameter larger than that of the restricting portion, and a second surface having a diameter smaller than that of the first surface.

[0007] According to the present invention, it is possible to reduce the noise of the kelly bar while achieving miniaturization. Note that problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view of an earth drill machine according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a longitudinal cross-sectional view of a kelly bar. [Figure 3] FIG. 1 is a cross-sectional view of a kelly bar. [Figure 4] FIG. 3 is a vertical cross-sectional view of a main part A of the kelly bar shown in FIG. 2. [Figure 5] FIG. [Figure 6] FIG. 2 is a perspective view showing the internal configuration of the kelly bar. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. 10 is an explanatory diagram showing the dimensional relationship between the buffer material and the stopper. [Figure 10] FIG. 10 is a vertical cross-sectional view of a cushioning material according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a side view of an earth drill 1 according to this embodiment.

[0010] (Earth drill machine 1) As shown in Figure 1, the earth drill machine 1 of this embodiment is configured with a main body 10 consisting of a running body 2 and a rotating body 3 rotatably supported on the running body 2, and a boom-type front attachment 100.

[0011] The running body 2 travels when a running motor (not shown) is driven to rotate. The rotating body 3 rotates relative to the running body 2 when a swing motor (not shown) is driven to rotate. The rotating body 3 mainly includes a cab 4, a counterweight 5, a rear winch 6, and a front winch 7.

[0012] The cab 4 is provided at the front end of the revolving body 3. The cab 4 has an internal space in which an operator of the earth drill machine 1 sits. Also, the internal space of the cab 4 is provided with various operating devices (levers, switches) for operating the earth drill machine 1, although these are not shown. Then, when the operator sitting in the internal space of the cab 4 operates the operating devices, the traveling body 2 travels, the revolving body 3 rotates, and the front attachment 100 operates.

[0013] The counterweight 5 is provided at the rear end of the rotating body 3. The counterweight 5 is a heavy object that balances the weight of the front attachment 100 and cargo (not shown). The rear winch 6 is driven to rotate by a rear winch hydraulic motor (not shown) and winds up or down a main hoisting rope (kelly rope) 116. The front winch 7 is driven to rotate by a front winch hydraulic motor (not shown) and winds up or down an auxiliary hoisting rope 117. Note that the main hoisting rope 116 does not necessarily have to be wound up or down by the rear winch 6, and may be wound up or down by the front winch 7.

[0014] (Front attachment 100) The front attachment 100 is of a boom type and performs excavation work and lifting work in accordance with the operation of an operating device. Note that a leader type front attachment may be used instead of the boom type.

[0015] The front attachment 100 includes a boom 110, a front frame 112, a rotary frame 113, a main hoist sheave 114, an auxiliary hoist sheave 115, a main hoist rope 116, an auxiliary hoist rope 117, a kelly bar 140, a rotary drive 120, a boom hoisting cylinder 124, a boom telescopic cylinder (not shown), a front frame hoisting cylinder 125, a rotary frame hoisting cylinder 126, a thruster cylinder 127, an excavation tool (not shown), and a hook 122.

[0016] The boom 110 is mounted on the revolving unit 3 so that it can be raised and lowered. In this embodiment, the boom 110 is a telescopic boom type, but it may also be a lattice boom type. The boom 110 rises or lowers relative to the revolving unit 3 as the boom hoisting cylinder 124 extends and retracts.

[0017] The front frame 112 is mounted on the boom 110 so as to be able to be raised and lowered. The angle of the front frame 112 relative to the boom 110 can be adjusted in accordance with the extension and contraction of a front frame raising and lowering cylinder 125.

[0018] The rotary frame 113 is rotatably mounted on the tip of the front frame 112. The angle of the rotary frame 113 relative to the front frame 112 can be adjusted in accordance with the extension and contraction of the rotary frame raising and lowering cylinder 126.

[0019] The rotary drive 120 and the thruster cylinder 127 are attached to the rotary frame 113. The rotary drive 120 moves up and down as the thruster cylinder 127 extends and retracts.

[0020] The kelly bar 140 is suspended from the lower end of the main hoisting rope 116 that hangs down from the front end of the main hoisting sheave 114, and an excavation tool such as a drilling bucket is attached to the tip of the kelly bar 140. The rotary drive 120 then drives the kelly bar 140 to rotate, causing the excavation tool to excavate the ground.

[0021] (Kellyba 140) Next, a description will be given of the details of the kelly bar 140. Fig. 2 is a vertical cross-sectional view of the kelly bar 140, Fig. 3 is a horizontal cross-sectional view of the kelly bar 140, Fig. 4 is a vertical cross-sectional view of a main portion A (see Fig. 2) of the kelly bar 140, and Fig. 5 is a plan view of the kelly bar 140.

[0022] As shown in these figures, the kelly bar 140 is configured by fitting together a plurality of (e.g., five) cylindrical divided kelly bars 141a-141e (an outer cylindrical member, an inner cylindrical member) having different horizontal cross-sectional sizes so that they are relatively movable in the axial direction (vertically movable) and relatively expandable and contractible. The kelly bar 140 is suspended by connecting the main hoisting rope 116 to a connection part 151 provided at the upper end of the innermost divided kelly bar 141e. A bucket coupling part 160 is provided at the lower end of the innermost divided kelly bar 141e, and various excavation tools are coupled to this bucket coupling part 160.

[0023] Spring bearing 161 is provided on the upper part of bucket connecting portion 160. Spring bearing 162 is attached to the upper part of spring bearing 161 so as to be movable up and down relative to split kelly bar 141e. A coil spring 163, which is an elastic body, is interposed between these spring bearings 161 and 162. This coil spring 163 serves to absorb the impact when split kelly bar 141e collides with the lower end of the adjacent split kelly bar 141d when kelly bar 140 contracts.

[0024] A plurality of ribs 142a-142e (three in the example of FIG. 3) for receiving rotational force are welded to the outer periphery of the divided kelly bars 141a-141e along almost the entire length in the vertical direction. The rib 142a of the outermost divided kelly bar 141a is fitted into a groove 120a for transmitting rotational force provided on the inner periphery of the rotary drive 120 (FIG. 3).

[0025] The ribs 142b to 142e of the other split kelly bars 141b to 141e are inserted between a plurality of plates 143a to 143d (six in the example of FIG. 3) for transmitting rotational force which are aligned in the circumferential direction and welded to the lower inner circumferential surfaces of the split kelly bars 141a to 141d adjacent to the outside, respectively.

[0026] The rotational force of the rotary drive 120 is transmitted to the rib 142a of the outermost divided kelly bar 141a (outer cylindrical member) that abuts against the groove 120a, and then the ribs 142b-142e of the divided kelly bars 141b-141e (inner cylindrical member) abut against the plates 143a-143d of the adjacent outer divided kelly bars 141a-141d, thereby transmitting the rotational force to the innermost divided kelly bar 141e. In this way, an excavation tool such as a bucket attached to the bucket connecting portion 160 of the divided kelly bar 141e rotates.

[0027] A pair of stoppers (restricting portions) 145b-145d, 146b-146d are attached to the upper outer peripheral surfaces of the split kelly bars 141b-141d, respectively, at intervals from each other in the axial direction of the kelly bars 141b-141d (FIG. 4). That is, the stoppers 145b-145d, 146b-146d are provided in pairs, one above the other. When the split kelly bars 141b-141d descend relative to the split kelly bars 141a-141c adjacent to them on the outside, the lower stoppers 146b-146d are locked by locking portions (not shown) provided on the lower inner peripheral surfaces of the split kelly bars 141a-141c, respectively, thereby preventing the split kelly bars 141b-141d from coming off.

[0028] Cushioning materials 170, 171, and 172 are fitted between the pair of stoppers 145b and 146b, between the pair of stoppers 145c and 146c, and between the pair of stoppers 145d and 146d, respectively. The cushioning materials 170, 171, and 172 are intended to prevent the generation of impact noise due to lateral vibration of the kelly bar 140. Details of the cushioning materials 170, 171, and 172 will be described later.

[0029] Flange 154 is provided at the upper end of split kelly bar 141a on the outermost periphery. Shock absorbing material 155 is attached to the underside of flange 154 with bolts 153 (FIGS. 2 and 5). Shock absorbing material 155 is made of, for example, hard rubber, plastic, or a combination of these, and is formed in a ring shape. Shock absorbing material 155 prevents the generation of impact and impact noise when it comes into contact with the upper surface of the rotary drive body of rotary drive 120.

[0030] Next, we will explain the details of the cushioning materials 170, 171, and 172. Fig. 6 is a perspective view showing the internal configuration of the kelly bar 140, Fig. 7 is an exploded perspective view of the cushioning material 170, Fig. 8 is a vertical cross-sectional view of the cushioning material 170, and Fig. 9 is an explanatory diagram showing the dimensional relationship between the cushioning material 170 and the stoppers 145b and 146b.

[0031] As shown in these figures, the cushioning material 170 is made up of multiple (four in the example of FIG. 6) cushioning pieces 170a to 170d. The cushioning pieces 170a to 170d are made of, for example, nylon resin. Of course, they may also be made of other resin materials. When the four cushioning pieces 170a to 170d are integrated, the ring-shaped cushioning material 170 is formed.

[0032] In this embodiment, the buffer pieces 170a to 170d have the same shape. That is, the buffer pieces 170a to 170d are obtained by dividing the buffer material 170 into four equal parts. Of course, the buffer pieces 170a to 170d may have different shapes.

[0033] In this embodiment, although the cushioning materials 170, 171, and 172 have different diameters, they are otherwise configured the same, and the cushioning materials 171 and 172 are configured to have four equal cushioning pieces 171a to 171d and 172a to 172d, like the cushioning material 170. Therefore, in the following explanation, the configuration of the cushioning material 170 and, among the cushioning pieces 170a to 170d that constitute it, particularly cushioning piece 170c will be explained in detail, and explanations of the other cushioning materials 171 and 172 and the cushioning pieces 171a to 171d and 172a to 172d that constitute them will be omitted.

[0034] As described above, the cushioning material 170 includes four cushioning pieces 170a to 170d, and a step is formed on the upper part of the outer circumferential surface. As shown in Figures 7 and 8, for example, cushioning piece 170c has a large diameter portion 186c and a small diameter portion 187c, and a step is formed at the boundary of the outer periphery between large diameter portion 186c and small diameter portion 187c.

[0035] Specifically, the buffer piece 170c has a first outer peripheral surface (first surface) 180c, a second outer peripheral surface (second surface) 181c, an upper surface 182c, a stepped surface 183c, a lower surface 184c, and an inner peripheral surface 185c. The stepped surface 183c is formed by the diameter of the second outer peripheral surface 181c being smaller than the diameter of the first outer peripheral surface 180c.

[0036] As shown in FIG. 9, the radius R11 of the first outer peripheral surface 180c is larger than the radius R2 of the outer peripheral surfaces of the stoppers 145b and 146b. The radius R12 of the second outer peripheral surface 181c is smaller than the radius R11 of the first outer peripheral surface 180c and the radius R2 of the stoppers 145b and 146b. Therefore, when the buffer material 170 is mounted between the pair of upper and lower stoppers 145b and 146b, the first outer peripheral surface 180c of the buffer piece 170c protrudes radially outward from the outer peripheral surfaces of the stoppers 145b and 146b, and the second outer peripheral surface 181c of the buffer piece 170c forms an annular groove recessed below the stoppers 145b and 146b. That is, the second outer peripheral surface 181c of the buffer piece 170c, the step surface 183c, and the lower surface of the stopper 145b form an annular groove. The inner diameter R13 of the inner circumferential surface 185c of the buffer piece 170c is equal to the outer diameter of the divided kelly bar 141b.

[0037] Next, a method of attaching the cushioning material 170 will be described. First, the cushioning pieces 170a to 170d are placed between the stoppers 145b and 146b. Then, to prevent the cushioning pieces 170a to 170d from coming apart, a binding band (binding member) 190 is wound around the groove, i.e., the second outer peripheral surface 181c, to firmly bind the cushioning pieces 170a to 170d (FIGS. 7 and 8). Then, when the inner divided kelly bar 141b is inserted into the outer divided kelly bar 141a, the first outer peripheral surface 180c of the cushioning material 170 protrudes radially beyond the stoppers 145b and 146b, so that the first outer peripheral surface 180c of the cushioning material 170 comes into sliding contact with the inner peripheral surface of the outer divided kelly bar 141a, and the inner divided kelly bar 141b is housed inside the outer divided kelly bar 141a.

[0038] In this way, the axial movement of cushioning material 170 is restricted by stoppers 145b, 146b, and the cushioning material 170 abuts against the inner peripheral surface of outer divided kelly bar 141a, restricting its radial movement. This allows cushioning material 170 to mitigate the impact and collision noise caused by a collision between outer divided kelly bar 141a and inner divided kelly bar 141b. Note that instead of binding band 190, cushioning material 170 may be wrapped around a cord-like member such as a rope or wire.

[0039] As described above, according to this embodiment, the following advantageous effects can be achieved.

[0040] Since the buffer pieces 170a to 170d can be bundled using the cable ties 190 at the stepped portions (grooves) of the buffer material 170, i.e., the second outer peripheral surface 181c, the radial dimension can be reduced compared to when the buffer material is fixed with bolts as in the past. Therefore, even if the number of steps of the kelly bar 140 is increased, the outer diameter of the kelly bar 140 can be reduced. Furthermore, since the diameter of the kelly bar 140 can be reduced, the weight of the kelly bar 140 can be reduced accordingly. Moreover, since the buffer material 170 is provided, damage and impact noise due to collision between the divided kelly bars can be suppressed. In other words, according to this embodiment, the noise of the kelly bar 140 can be reduced while still achieving a compact size.

[0041] Furthermore, since the cushioning material 170 is fitted between the stoppers 145b and 146b, the force in the thrust direction acting on the cushioning material 170 as the kelly bar 140 expands and contracts can be received by the stoppers 145b and 146b, thereby preventing the cushioning material 170 from falling off or being damaged. Furthermore, since the cushioning material 170 is made of nylon resin, it has excellent abrasion resistance.

[0042] Furthermore, according to this embodiment, the kelly bar 140 can be assembled simply by bundling the buffer pieces 170a to 170d with the binding band 190, which simplifies the assembly process compared to the prior art in which buffer materials are fixed with bolts.

[0043] In the above-described embodiment, the radius R12 of the second outer peripheral surface 181c is smaller than the radius R11 of the first outer peripheral surface 180c and smaller than the radius R2 of the stoppers 145b and 146b. However, this is not necessarily the case. For example, the radius R11 of the first outer peripheral surface 180c > the radius R12 of the second outer peripheral surface 181c > the radius R2 of the stoppers 145b and 146b may be satisfied. Furthermore, the second outer peripheral surface 181c does not necessarily have to be a uniform circumferential surface. In other words, the surface shape of the second outer peripheral surface 181c is not important as long as the cable tie 190 can be wrapped around it.

[0044] <Modification> Next, a modified example will be described. Fig. 10 is a longitudinal cross-sectional view of cushioning material 270 according to the modified example. Cushioning material 270 according to the modified example is made up of four cushioning pieces 270a to 270d, and is formed into a ring shape without any steps as a whole. As shown in Fig. 10, one of these cushioning pieces, cushioning piece 270c, is configured with a rectangular longitudinal cross-section having a first outer peripheral surface 280c, an upper surface 282c, a lower surface 284c, and an inner peripheral surface 285c.

[0045] In this modified example, when buffer pieces 270a to 270d are bundled with cable ties 190, the cable ties 190 protrude from the outer peripheral surface of buffer material 270, interfering with the expansion and contraction of the split kelly bars. Therefore, in this modified example, buffer pieces 270a to 270d are temporarily bundled together using thin tape (temporary bundling member) 290 instead of cable ties 190. The thickness of tape 290 need only be thin enough not to interfere with the insertion of the split kelly bars into one another.

[0046] Simply bundling the buffer pieces 270a to 270d with tape 290 does not ensure that the buffer pieces 270a to 270d are firmly fixed, but if the buffer pieces 270a to 270d are inserted into the split kelly bar 141a while still in a state where they are temporarily bound with tape 290, then, for example, the first outer peripheral surface 280c of buffer piece 270c will come into contact with the inner peripheral surface of the split kelly bar 141a, and the buffer pieces 270a to 270d will be contained between the pair of upper and lower stoppers 145b, 146b, and therefore the effect of preventing damage and impact noise due to collision between the split kelly bars will not be lost.

[0047] In this way, according to the modified example, the shape of the buffer pieces 270a-270d can be simplified, that is, the buffer material 270 can be made into a simple ring shape without any steps, thereby reducing manufacturing costs. Furthermore, since the buffer pieces 270a-270d can be bound together by simply applying tape 290, there is also the advantage that the assembly work of the kelly bar 140 becomes even easier.

[0048] The buffer pieces 270a to 270d may be integrated by fitting together recesses and protrusions without using the tape 290. Alternatively, the buffer pieces 270a to 270d may be integrated using an adhesive instead of the tape 290.

[0049] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention. The present invention covers all technical matters included in the technical ideas described in the claims. The above-described embodiments are preferred examples, but a person skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed in this specification, and these are included in the technical scope described in the appended claims.

[0050] For example, although the configuration in which a pair of upper and lower stoppers 145b, 146b are used to restrict the axial movement of cushioning material 170 has been exemplified, other configurations can be used as long as they can restrict the axial movement of cushioning material 170. For example, one of the upper and lower stoppers may be a ring-shaped stopper, and the other may be a plurality of protrusions spaced apart in the circumferential direction. Also, a configuration in which a groove is provided on the outer circumferential surface of a split kelly bar and cushioning material 170 is fitted into the groove may be used.

[0051] Furthermore, the material of buffer 170 may be any material that generates less noise when it collides with metal than the material of stoppers 145b and 146b. For example, in addition to nylon resin, general-purpose engineering plastics (such as polycarbonate) may be used, or buffer 170 may be made of wood or the like. In other words, buffer 170 is a member that generates less noise when it collides with metal than stoppers 145b and 146b.

[0052] Furthermore, in the above-described embodiment, a configuration has been exemplified in which the cushioning materials 170, 171, 172, the stoppers 145b to 145d and the stoppers 146b to 146d are provided for the inner divided kelly bars 141b to 141d, but in the present invention, by providing these to at least one of the inner divided kelly bars 141b to 141d, it is possible to reduce the noise of the kelly bar while also achieving miniaturization. [Explanation of symbols]

[0053] 1 Earth drill machine 2. Running body 3 Rotating body 10 Main Unit 100 Front Attachment 110 Boom 120 rotary drive 120a groove 140 Kellyba 141a Divided kelly bar (outer cylindrical member) 141b~141e Divided kelly bars (inner cylindrical members) 142a~142e Rib 143a~143d Plates 145b~145d Stopper (restriction part) 146b~146d Stopper (restriction part) 151 Connection 153 volts 154 flange 155 Shock absorber 160 Bucket connection 161,162 Spring bearing 163 Coil spring 170,171,172 Cushioning material 170a~170d, 171a~171d, 172a~172d Buffer piece 180c First cylindrical surface (first surface) 181c Second cylindrical surface (second surface) 182c top surface 183c step surface 184c bottom surface 185c Inner surface 190 Cable ties (binding materials) 290 Tape (temporary binding material)

Claims

1. A kelly bar including an outer cylindrical member positioned at an outermost position, and a plurality of inner cylindrical members positioned inside the outer cylindrical member and movable in an axial direction of the outer cylindrical member, At least one of the plurality of inner cylindrical members has an outer periphery including: a cushioning material consisting of a plurality of cushioning pieces; a restricting portion that restricts movement of the buffer material in the axial direction, The buffer material has a first surface having a larger diameter than the restricting portion and a second surface having a smaller diameter than the first surface. A Kelly bar characterized by:

2. The kelly bar according to claim 1, the restricting portion is configured as a pair spaced apart from each other in the axial direction of the inner cylindrical member, The buffer material is fitted between the pair of restricting portions. A Kelly bar characterized by:

3. The kelly bar according to claim 1, The second surface has a smaller diameter than the restricting portion. A Kelly bar characterized by:

4. The kelly bar according to claim 3, a bundling member for bundling the plurality of buffer pieces; The binding member is attached to the second surface so as to fit inside the outer periphery of the restricting portion. A Kelly bar characterized by:

5. a kelly bar formed by an outer cylindrical member positioned at the outermost position and a plurality of inner cylindrical members positioned inside the outer cylindrical member and movable in an axial direction of the outer cylindrical member, At least one of the plurality of inner cylindrical members has an outer periphery including: a cushioning material consisting of a plurality of cushioning pieces; a restricting portion that restricts movement of the buffer material in the axial direction; A temporary bundling member that temporarily bundles the plurality of buffer pieces, A Kelly bar characterized by:

6. An earth drill equipped with the kelly bar according to any one of claims 1 to 5.

Images