Bucket for construction equipment

Abstract

To provide a bucket for a construction machine capable of making a clamshell bite the ground well even if the ground is hard.SOLUTION: A bucket 21 is provided with: a support body 31 suspended in a space inside of a casing tube installed in the ground; clamshells 33a, 33b connected to the support body 31 rotatably around a horizontal axis and excavating the ground based on open / close motions; a plurality of antislip devices 52 comprising contact surfaces 51 pressed against an inner wall surface of the casing tube; and reaction force transmission members 55, 57 connected to the support body 31 swingably around horizontal axis 54 56 and supporting the antislip devices 52 at open ends to place the contact surfaces 51 at a height higher than those of the horizontal axis 54, 56.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a bucket for construction machinery that is suspended in the space inside a casing tube and has a clam shell.

Background Art

[0002] For example, Patent Document 1 discloses an excavation device that discharges earth and sand from inside a casing tube. The excavation device includes a plurality of grippers (anti-slip members) having contact surfaces that are pressed against the inner wall surface of the casing tube. The grippers can fix a clam shell at a specific height position inside the casing tube. A hydraulic cylinder in a horizontal posture is used when pressing the grippers.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the ground is hard, the clam shell cannot bite into the ground. Therefore, even when the clam shell is closed, the clam shell cannot scoop up earth and sand. The clam shell will perform an idle stroke.

[0005] According to the verification by the present inventor, when the closing operation of the clam shell is performed on hard ground, the clam shell cannot be fixed at a specific height position only by the driving force of the hydraulic cylinder. The grippers described in Patent Document 1 could not effectively prevent the idle stroke of excavation.

[0006] The present invention aims to provide a construction equipment bucket that can effectively embed a clamshell into the ground, even in hard ground conditions. [Means for solving the problem]

[0007] According to one embodiment of the present invention, a construction bucket is provided comprising: a support body suspended in a space within a casing tube installed underground; a clamshell connected to the support body so as to be rotatable about a horizontal axis and excavating the ground based on an opening and closing operation; a plurality of anti-slip surfaces having contact surfaces pressed against the inner wall surface of the casing tube; and a reaction force transmission member connected to the support body so as to be swingable about a horizontal axis, supporting the anti-slip surfaces at its open end and positioning the contact surfaces higher than the horizontal axis.

[0008] Once the casing tube is installed underground, the construction equipment bucket is suspended within the space inside the casing tube. The clamshell closes as the ground is excavated. As the clamshell closes, it scoops up soil. When the construction equipment bucket is lifted out of the casing tube, the clamshell opens outside the casing tube. As the clamshell opens, the soil is discharged out of the casing tube. In this way, excavation progresses inside the casing tube.

[0009] When the anti-slip contact surface is pressed against the inner wall of the casing tube during excavation, the construction equipment bucket is fixed inside the casing tube. The construction equipment bucket is held at a fixed height inside the casing tube. If the ground is hard, a large upward reaction force acts on the support when the clamshell closes during excavation. At this time, since the anti-slip contact surface is pressed against the inner wall of the casing tube at a position higher than the horizontal axis, the upward reaction force acting along the horizontal axis is converted into an outward force by the action of the reaction force transmission member. A pressing force acts on the anti-slip surface toward the inner wall of the casing tube. In this way, slippage of the contact surface is suppressed. Even if the ground is hard, the clamshell can bite into the ground well.

[0010] The construction equipment bucket may include a first hydraulic cylinder connected to the support and the clamshell to realize the opening and closing operation of the clamshell; a second hydraulic cylinder connected to the support and the reaction force transmission member to generate a driving force to press the anti-slip surface against the inner wall; and a hydraulic circuit connected to the first and second hydraulic cylinders to supply hydraulic pressure to the first hydraulic cylinder to start the closing operation of the clamshell after the driving force has been generated by the second hydraulic cylinder. Due to the action of the hydraulic circuit, the clamshell closing operation is performed after the construction equipment bucket is fixed inside the casing tube, so that missed excavations can be effectively prevented. Efficient excavation can be achieved inside the casing tube. [Effects of the Invention]

[0011] As described above, according to the disclosed invention, a construction equipment bucket can be provided that can effectively embed a clamshell into the ground even when the ground is hard. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic left side view showing the overall configuration of a construction machine, namely a crawler crane, according to one embodiment of the present invention. [Figure 2] This is a right side view of a crawler crane. [Figure 3] This is an enlarged side view of the bucket. [Figure 4] This is a plan view of the bucket. [Figure 5] This is a schematic side view of the bucket showing the structure of the anti-slip and reaction force transmission members. [Figure 6] This is a diagram of a hydraulic circuit. [Figure 7] This is a conceptual diagram illustrating the operation of the bucket. [Modes for carrying out the invention]

[0013] One embodiment of the present invention will be described below with reference to the attached drawings.

[0014] Figure 1 schematically shows the overall configuration of a construction machine, i.e., a crawler crane, used in the all-casing construction method. The construction machine 11 comprises a drive unit 14 that supports the left and right crawlers 12 and 13, and a slewing unit 16 that is connected to the drive unit 14 so as to be able to rotate around a vertical axis and supports the operator's cab 15. The operator sits in the operator's cab 15. The crawlers 12 and 13 move in response to the operator's operation. The construction machine 11 moves based on the movement of the crawlers 12 and 13. Wheels may be used instead of crawlers 12 and 13 to achieve movement.

[0015] The slewing body 16 supports a boom 17 that can be raised and lowered around a horizontal axis. The boom 17 comprises a first body 17a connected to the slewing body 16, a second body 17b housed within the space of the first body 17a so as to be able to move back and forth, and a third body 17c housed within the space of the second body 17b so as to be able to move back and forth. A hydraulic cylinder 18 is connected between the boom 17 and the slewing body 16. The boom 17 is raised and lowered according to the extension and retraction of the hydraulic cylinder 18. A hydraulic cylinder is connected between the first body 17a and the second body 17b. A hydraulic cylinder is connected between the second body 17b and the third body 17c. The boom 17 can be extended and lowered in a telescopic manner according to the extension and retraction of the hydraulic cylinders. Each hydraulic cylinder is connected to a hydraulic circuit. Through the operation of the hydraulic circuit, hydraulic pressure from a hydraulic source can be supplied to each hydraulic cylinder.

[0016] A bucket 21 is attached to the tip of the boom 17. The bucket 21 is suspended and supported in the direction of gravity. Here, the bucket 21 is coupled to a wire rope 22 hanging down from the tip of the boom 17. A sheave 23 is coupled to the tip of the boom 17 so as to be rotatable around a horizontal axis. The sheave 23 guides the forward and backward movement of the wire rope 22. The end of the wire rope 22 hanging down from the sheave 23 is coupled to the tip of the boom 17. The bucket 21 is supported by a sheave 24 that engages with the wire rope 22 hanging down between the sheave 23 and the coupling end.

[0017] The wire rope 22 can be wound around a winch 25 that is fixed to, for example, the first body 17a of the boom 17. When the wire rope 22 is wound around the winch 25, the bucket 21 rises. When the wire rope 22 is unwound from the winch 25, the bucket 21 descends. A hydraulic motor is connected to the winch 25. The hydraulic motor drives the winch 25 according to the hydraulic pressure supplied from a hydraulic source. In addition, the bucket 21 may be used as a so-called hydraulic clamp or as a telescopic clamp.

[0018] As shown in FIG. 2, a release end of a hydraulic hose 26 that hangs down from the tip of the boom 17 is coupled to the bucket 21. A sheave 27 is coupled to the tip of the boom 17 so as to be rotatable about a horizontal axis. The sheave 27 guides the forward and backward movement of the hydraulic hose 26.

[0019] A hose reel 28 for winding the hydraulic hose 26 is fixed to the first body 17a of the boom 17. The hose reel 28 winds the hydraulic hose 26 around the rotating body when the bucket 21 rises. When the bucket 21 descends, the hydraulic hose 26 is unwound from the rotating body. A hydraulic circuit is connected to the hose reel 28 via a hydraulic pipe 29. The hose reel 28 transmits the hydraulic pressure of the hydraulic circuit from the hydraulic pipe 29 to the hydraulic hose 26.

[0020] A hydraulic motor is connected to the hose reel 28. The hydraulic motor drives the rotating body of the hose reel 28 according to the hydraulic pressure supplied from a hydraulic source. The hydraulic hose 26 can be wound around the rotating body according to the drive of the rotating body. The operation of the hose reel 28 may be interlocked with the operation of the winch 25.

[0021] Bucket 21 is configured as a so-called clamshell bucket. That is, as shown in Figure 3, bucket 21 comprises a support 31 connected to a sheave 24 and suspended by a wire rope 22, and a pair of clamshells 33a and 33b connected to the support 31 so as to be rotatable around a horizontal axis 32. Each clamshell 33a and 33b is rotatably supported on a common shaft 34 fixed to the support 31. The axis of the shaft 34 is set parallel to the rotation axis of the sheave 24.

[0022] Each clamshell 33a and 33b has bearings and comprises two connecting plates 35 extending along a virtual plane perpendicular to the axis of the shaft 34, and a shovel body 36 connecting the edges of the two connecting plates 35 at a position away from the axis of the shaft 34. The shovel body 36 is displaced between a first position in which it establishes an upright posture on the ground and a second position in which it descends around the axis of the shaft 34 and interlocks its mating ends with the other. When the two shovel bodies 36 are in the first position, the clamshells 33a and 33b open. When the two shovel bodies 36 are in the second position, the clamshells 33a and 33b close. The mating ends of the shovel bodies 36 have multiple claws 37 that bite into the ground in the first position and recesses that receive the claws 37 of the other side in the second position. In the pair of clamshells 33a and 33b, the claws 37 are arranged alternately.

[0023] A first hydraulic cylinder 41 is connected to each individual clamshell 33a, 33b and to the support 31. The first hydraulic cylinder 41 comprises a cylinder body 43 that is rotatable around an axis 42 parallel to the axis of the shaft 34 and connected to the support 31, a piston 44 housed within the cylinder body 43 that divides the internal space of the cylinder body 43 into a first hydraulic chamber and a second hydraulic chamber, and a rod 46 connected to the piston 44 that is rotatable around an axis 45 parallel to the axis of the shaft 34 and connected to the clamshells 33a, 33b. When hydraulic pressure is applied to the second hydraulic chamber, the rod 46 is retracted to its maximum extent into the cylinder body 43 and the first hydraulic cylinder 41 retracts. At this time, the clamshells 33a, 33b open. When hydraulic pressure is applied to the first hydraulic chamber, the rod 46 protrudes to its maximum extent from the cylinder body 43 and the first hydraulic cylinder 41 extends. At this time, the clamshells 33a and 33b close. The first hydraulic cylinder 41 enables the opening and closing operation of the clamshells 33a and 33b.

[0024] As shown in Figure 4, anti-slip devices 52 having contact surfaces 51 that are pressed against the inner wall surface of the casing tube during operation are connected to the support 31. The anti-slip devices 52 are arranged at specific intervals around the central axis 53 of the casing tube. When arranging the anti-slip devices 52, the balance of forces acting outward from the anti-slip devices 52 (away from the central axis 53 of the casing tube) is taken into consideration. Here, two sets of anti-slip devices 52 are used, which push against the casing tube along a diameter line perpendicular to the central axis 53 in a horizontal plane. As shown in Figure 5, the anti-slip devices 52 are supported by a first reaction force transmission member 55 which is connected to the support 31 so as to be able to swing around a first horizontal axis 54, and a second reaction force transmission member 57 which is connected to the support 31 so as to be able to swing around a second horizontal axis 56 located below the first horizontal axis 54. The first horizontal axis 54 and the second horizontal axis 56 are arranged parallel to each other.

[0025] The upper end of the anti-slip surface 52 is connected to the outer end of the first reaction force transmission member 55 so as to be rotatable about a third horizontal axis 58 parallel to the first horizontal axis 54. A first projection 59a is integrally formed on the upper end of the anti-slip surface 52, projecting outward and forming a contact surface 51 at its outer end. The first projection 59a moves between a locked position, set higher than the first horizontal axis 54, and an unlocked position, which is higher than the locked position but displaced inward from the locked position, in response to the oscillation of the first reaction force transmission member 55. When the first reaction force transmission member 55 is oscillating, the first projection 59a is maintained at a position higher than the first horizontal axis 54. The contact surface 51 is formed by a horizontally extending ridge of the first projection 59a.

[0026] The lower end of the anti-slip material 52 is connected to the outer end of the second reaction force transmission member 57 so as to be rotatable about a fourth horizontal axis 61 parallel to the second horizontal axis 56. A second projection 59b is integrally formed on the lower end of the anti-slip material 52, projecting outward and forming a contact surface 51 at its outer end. The second projection 59b moves between a locked position, set higher than the second horizontal axis 56, and an unlocked position, which is higher than the locked position but displaced inward from the locked position, in response to the oscillation of the second reaction force transmission member 57. When the second reaction force transmission member 57 is oscillating, the second projection 59b is maintained at a position higher than the second horizontal axis 56. The contact surface 51 is formed by a horizontally extending ridge of the second projection 59b.

[0027] Here, the distance between the first horizontal axis 54 and the third horizontal axis 58 is set to be equal to the distance between the second horizontal axis 56 and the fourth horizontal axis 61. In addition, the distance between the third horizontal axis 58 and the fourth horizontal axis 61 is set to be equal to the distance between the first horizontal axis 54 and the second horizontal axis 56. Therefore, the anti-slip device 52, the first reaction force transmission member 55, the second reaction force transmission member 57, and the support 31 form a link mechanism that enables the parallel movement of the anti-slip device 52 when the first reaction force transmission member 55 and the second reaction force transmission member 57 are oscillating. The vertical position of the anti-slip device 52 can be maintained when the first reaction force transmission member 55 and the second reaction force transmission member 57 are oscillating.

[0028] For each anti-slip surface 52, a second hydraulic cylinder 62 is connected to the first reaction force transmission member 55 and the support body 31. The second hydraulic cylinder 62 comprises a cylinder body 64 connected to the support body 31 so as to be rotatable around an axis 63 parallel to the first horizontal axis 54 and the second horizontal axis 56; a piston housed within the cylinder body 64, which divides the internal space of the cylinder body 64 into a first hydraulic chamber and a second hydraulic chamber; and a rod 66 connected to the piston, which is connected to the first reaction force transmission member 55 so as to be rotatable around an axis 65 parallel to the first horizontal axis 54 and the second horizontal axis 56. When hydraulic pressure is applied to the first hydraulic chamber, the rod 66 protrudes to its maximum extent from the cylinder body 64 and the second hydraulic cylinder 62 extends. At this time, the first projection 59a and the second projection 59b are positioned in the unlocked position. When hydraulic pressure is applied to the first hydraulic chamber, the rod 66 is retracted to its maximum extent into the cylinder body 64 and the second hydraulic cylinder 62 retracts. At this time, the first projection 59a and the second projection 59b are positioned in the locked position. The anti-slip 52, the first reaction force transmission member 55, and the second reaction force transmission member 57 are positioned to avoid interference with the operating clamshells 33a and 33b.

[0029] As shown in Figure 6, a hydraulic circuit 71 is connected to the first hydraulic cylinder 41 and the second hydraulic cylinder 62. The hydraulic circuit 71 includes a first oil passage 73 that connects the second hydraulic chamber 64a of the second hydraulic cylinder 62 to the first port of the directional control valve 72, and a second oil passage 74 that connects the first hydraulic chamber 64b of the second hydraulic cylinder 62 to the second port of the directional control valve 72. A third oil passage 76 is connected to the first oil passage 73, branching off from a first branching point 75 and connecting to the first hydraulic chamber 43a of the first hydraulic cylinder 41. A fourth oil passage 78 is connected to the second oil passage 74, branching off from a second branching point 77 and connecting to the second hydraulic chamber 43b of the first hydraulic cylinder 41. The directional control valve 72 can be switched between a first position in which hydraulic pressure from the hydraulic unit 79 is supplied to the first oil passage 73 and hydraulic fluid is recovered from the second oil passage 74, and a second position in which hydraulic pressure from the hydraulic unit 79 is supplied to the second oil passage 74 and hydraulic fluid is recovered from the first oil passage 73. The hydraulic unit 79 is equipped with a hydraulic power source that pumps hydraulic fluid from an oil tank to generate hydraulic pressure.

[0030] In the first oil passage 73, a check valve 81 is positioned between the first branching point 75 and the second hydraulic chamber 64a of the second hydraulic cylinder 62. In the second oil passage 74, a check valve 82 is positioned between the second branching point 77 and the first hydraulic chamber 64b of the second hydraulic cylinder 62. The two check valves 81 and 82 constitute a double pilot check valve. When hydraulic pressure is supplied to the first oil passage 73 from the hydraulic unit 79, the check valve 82 in the second oil passage 74 is opened. When hydraulic pressure is supplied to the second oil passage 74 from the hydraulic unit 79, the check valve 81 in the first oil passage 73 is opened. In this way, hydraulic pressure is supplied from the hydraulic unit 79 to either the first hydraulic chamber 64b or the second hydraulic chamber 64a of the second hydraulic cylinder 62.

[0031] In the third oil passage 76, a relief valve 83 is positioned between the first branching point 75 and the first hydraulic chamber 43a of the first hydraulic cylinder 41. The relief valve 83 supplies hydraulic pressure to the first hydraulic chamber 43a of the first hydraulic cylinder 41 at a predetermined pressure or higher. A check valve 84 is connected in parallel to the relief valve 83. The check valve 84 releases hydraulic pressure from the first hydraulic chamber 43a of the first hydraulic cylinder 41. Since the third oil passage 76 branches off from the first oil passage 73, when the pressure in the second hydraulic chamber 64a of the second hydraulic cylinder 62 rises to a predetermined pressure, hydraulic pressure is supplied to the first hydraulic chamber 43a of the first hydraulic cylinder 41 via the third oil passage 76.

[0032] In the fourth oil passage 78, a relief valve 85 is positioned between the second branching point 77 and the second hydraulic chamber 43b of the first hydraulic cylinder 41. The relief valve 85 supplies hydraulic pressure to the second hydraulic chamber 43b of the first hydraulic cylinder 41 at a predetermined pressure or higher. A check valve 86 is connected in parallel to the relief valve 85. The check valve 86 releases hydraulic pressure from the second hydraulic chamber 43b of the first hydraulic cylinder 41. Since the fourth oil passage 78 branches off from the second oil passage 74, when the pressure in the first hydraulic chamber 64b of the second hydraulic cylinder 62 rises to a predetermined pressure, hydraulic pressure is supplied to the second hydraulic chamber 43b of the first hydraulic cylinder 41 via the fourth oil passage 78.

[0033] Next, the all-casing construction method using the construction machine 11 according to this embodiment will be described. As shown in Figure 7(a), the casing tube CY is installed in the ground. During installation, the casing tube CY is pressed in vertically from the ground Gr. At this time, the central axis 53 of the casing tube CY coincides with the direction of gravity. The casing tube CY is made of, for example, a stainless steel cylinder.

[0034] The ground Gr is excavated inside the casing tube CY. The bucket 21 is suspended in the space inside the casing tube during excavation. The bucket 21 descends towards the ground Gr inside the casing tube CY. As the bucket 21 descends, the wire rope 22 is released from the winch 25. The hydraulic hose 26 is released from the hose reel 28. The operator in the cab 15 operates the hydraulics to control the operation of the winch 25 and the hose reel 28.

[0035] At this time, hydraulic pressure acts on the second hydraulic chamber 43b in the first hydraulic cylinder 41. The first hydraulic cylinder 41 is retracted to its maximum extent. In the bucket 21, the clamshells 33a and 33b are maintained in the open position. Hydraulic pressure acts on the first hydraulic chamber 64b in the second hydraulic cylinder 62. The second hydraulic cylinder 62 is extended to its maximum extent. The first projection 59a and the second projection 59b of the anti-slip device 52 are held in the unlocked position.

[0036] When the bucket 21 touches the ground Gr, the shovel body 36 of the clamshells 33a and 33b stands upright on the ground Gr. The claws 37 dig into the ground Gr. At this point, hydraulic pressure acts on the first oil passage 73 and the third oil passage 76. Since the relief valve 83 is activated in the third oil passage 76, the introduction of hydraulic fluid into the first hydraulic chamber 43a of the first hydraulic cylinder 41 is prevented until the hydraulic pressure in the third oil passage 76 reaches a predetermined pressure. The hydraulic pressure in the first hydraulic chamber 43a is maintained. The contracted state of the first hydraulic cylinder 41 is maintained. In the bucket 21, the clamshells 33a and 33b are maintained in the open state.

[0037] The hydraulic pressure from the first oil passage 73 is introduced into the second hydraulic chamber 64a of the second hydraulic cylinder 62. The check valve 82 of the second oil passage 74 is opened. The hydraulic pressure acting on the second hydraulic chamber 64a causes the second hydraulic cylinder 62 to contract. In response to this contraction, the first reaction force transmission member 55 oscillates around the first horizontal axis 54, and the second reaction force transmission member 57 oscillates around the second horizontal axis 56. The first projection 59a and the second projection 59b of the anti-slip member 52 are displaced to the locked position. As shown in Figure 7(b), the contact surfaces 51 of the first projection 59a and the second projection 59b are pressed against the inner wall surface of the casing tube CY. The bucket 21 is fixed within the casing tube CY. The movement of the bucket 21 is constrained in the vertical and horizontal directions. The bucket 21 is held at a fixed height within the casing tube CY.

[0038] As the pressure in the first oil passage 73 and the third oil passage 76 increases and the hydraulic pressure in the second hydraulic chamber 64a of the second hydraulic cylinder 62 reaches a predetermined pressure, hydraulic pressure is introduced from the relief valve 83 to the first hydraulic chamber 43a of the first hydraulic cylinder 41. In the fourth oil passage 78, the hydraulic pressure is released from the check valve 86, bypassing the relief valve 85. As shown in Figure 7(c), the first hydraulic cylinder 41 extends due to the action of the hydraulic pressure. In the bucket 21, the clamshells 33a and 33b close. As the clamshells 33a and 33b close, they scoop up soil and sand.

[0039] If the ground is hard, a large upward reaction force acts on the support 31 from the ground when the clamshells 33a and 33b close during excavation. At this time, the contact surface 51 of the first projection 59a is pressed against the inner wall surface of the casing tube CY at a position higher than the first horizontal axis 54, so the upward reaction force acting on the first horizontal axis 54 is converted into an outward force by the action of the first reaction force transmission member 55. A pressing force acts on the anti-slip material 52 toward the inner wall surface of the casing tube CY. Similarly, the contact surface 51 of the second projection 59b is pressed against the inner wall surface of the casing tube CY at a position higher than the second horizontal axis 56, so the upward reaction force acting on the second horizontal axis 56 is converted into an outward force by the action of the second reaction force transmission member 57. A pressing force acts on the anti-slip material 52 toward the inner wall surface of the casing tube CY. In other words, since the points of application of force in the first reaction force transmission member 55 and the second reaction force transmission member 57 are positioned higher than the corresponding first horizontal axis 54 and second horizontal axis 56, respectively, the upward displacement of the support 31 is converted into an outward displacement of the anti-slip surface 52 by the action of the link mechanism. In this way, slippage of the contact surface 51 is suppressed. Regardless of the reaction force from the ground Gr, the bucket 21 can be held at a fixed height within the casing tube CY. Even if the ground is hard, the clamshells 33a and 33b can bite into the ground Gr well. The clamshells 33a and 33b can scoop up soil well in response to the closing operation.

[0040] Furthermore, because the hydraulic circuit 71 fixes the bucket 21 within the casing tube CY before the clamshells 33a and 33b are closed, misfires during excavation can be effectively prevented. Efficient excavation can be achieved within the casing tube CY.

[0041] When the clamshells 33a and 33b close, the directional control valve 72 is switched. Hydraulic pressure is applied from the hydraulic unit 79 to the second oil passage 74 and the fourth oil passage 78. Since the relief valve 85 is activated in the fourth oil passage 78, the introduction of hydraulic fluid into the second hydraulic chamber 43b of the first hydraulic cylinder 41 is blocked until the hydraulic pressure in the fourth oil passage 78 reaches a predetermined pressure. The hydraulic pressure in the second hydraulic chamber 43b is maintained. The extended state of the first hydraulic cylinder 41 is maintained. In the bucket 21, the clamshells 33a and 33b are maintained in the closed state.

[0042] The hydraulic pressure from the second oil passage 74 is introduced into the first hydraulic chamber 64b of the second hydraulic cylinder 62. The check valve 81 of the first oil passage 73 is opened. The hydraulic pressure acting on the first hydraulic chamber 64b causes the second hydraulic cylinder 62 to extend. In response to this extension, the first reaction force transmission member 55 swings about the first horizontal axis 54, and the second reaction force transmission member 57 swings about the second horizontal axis 56. The first projection 59a and the second projection 59b of the anti-slip member 52 are displaced to the unlocked position. As shown in Figure 7(d), the contact surfaces 51 of the first projection 59a and the second projection 59b move away from the inner wall surface of the casing tube CY. The bucket 21 is released from its fixed position within the casing tube CY. Movement of the bucket 21 is permitted in the vertical and horizontal directions.

[0043] The bucket 21 is lifted out of the casing tube CY. The bucket 21 rises within the space inside the casing tube CY. As the bucket 21 rises, the wire rope 22 is wound onto the winch 25. The hydraulic hose 26 is wound onto the hose reel 28. The operator in the cab 15 controls the operation of the winch 25 and hose reel 28 by operating the hydraulics.

[0044] At this time, the hydraulic pressure in the second oil passage 74 and the fourth oil passage 78 is maintained below a predetermined pressure. The relief valve 85 prevents the introduction of hydraulic fluid into the second hydraulic chamber 43b of the first hydraulic cylinder 41. The extended state of the first hydraulic cylinder 41 is maintained. In the bucket 21, the clamshells 33a and 33b are maintained in a closed state. In the second hydraulic cylinder 62, hydraulic pressure acts on the first hydraulic chamber 64b. The second hydraulic cylinder 62 is extended to its maximum extent. The first projection 59a and the second projection 59b of the anti-slip 52 are held in the unlocked position.

[0045] When the bucket 21 is lifted out of the casing tube CY, the hydraulic pressure is increased in the second oil passage 74 and the fourth oil passage 78 to a predetermined pressure. When the hydraulic pressure in the first hydraulic chamber 64b of the second hydraulic cylinder 62 reaches a predetermined pressure, the hydraulic pressure is introduced from the relief valve 85 to the second hydraulic chamber 43b of the first hydraulic cylinder 41. In the third oil passage 76, the hydraulic pressure is released from the check valve 84, bypassing the relief valve 83. The hydraulic pressure causes the first hydraulic cylinder 41 to contract. At the discharge position, the clamshells 33a and 33b open. As the clamshells open, the soil is discharged outside the casing tube CY. In this way, excavation progresses inside the casing tube CY. [Explanation of Symbols]

[0046] 11...Construction machinery, 31...Support, 32...Horizontal axis, 33a...Clamshell, 33b...Clamshell, 51...Contact surface, 52...Anti-slip, 54...Horizontal axis (first horizontal axis), 55...Reaction force transmission member (first reaction force transmission member), 56...Horizontal axis (second horizontal axis), 57...Reaction force transmission member (second reaction force transmission member), CY...Casing tube, Gr...Ground.

Claims

1. A support structure suspended within the space inside a casing tube installed underground, A clamshell is connected to the support so as to be rotatable around a horizontal axis and excavates the ground based on an opening and closing motion, Multiple anti-slip surfaces having contact surfaces that are pressed against the inner wall surface of the casing tube, A first projection is formed on the upper end of the anti-slip surface, protruding outward and forming the contact surface at its outer end, A second projection is formed at the lower end of the anti-slip surface, protruding outward and forming the contact surface at its outer end, A first reaction force transmission member is connected to the support so as to be able to swing around a first horizontal axis, supports the upper end of the anti-slip material with its open end, and positions the contact surface of the first projection higher than the first horizontal axis, A second reaction force transmission member is connected to the support so as to be able to swing around a second horizontal axis, supports the lower end of the anti-slip material with its open end, and positions the contact surface of the second projection higher than the second horizontal axis. A construction equipment bucket characterized by being equipped with the following features.

2. A construction equipment bucket according to claim 1, characterized in that the contact surface of the first projection is formed by a ridge extending horizontally on the first projection, and the contact surface of the second projection is formed by a ridge extending horizontally on the second projection.

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