JP2008007946A - Drilling unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drilling unit which can make a rotary push-in device smaller than a conventional type. <P>SOLUTION: This drilling unit 10 comprises: a casing 20 for excavation, in which portions 31 to be held are formed at each interval P along a longitudinal direction on the side of an outer peripheral surface 20a; a chuck device 60 which is provided with a split claw 70 advancing/receding toward the portion 31 of the casing 20; and the rotary push-in device 35 which rotates the chuck device 60 in the holding state of making the split claw 70 advance, and which vertically moves the chuck device 60 with a stroke corresponding to the interval P. In the casing 20, a plurality of sediment agitating protrusions 28, which are scattered in the state of protruding from the outer peripheral surface 20a, are provided in such a manner as not to collide with the chuck device 60 which is vertically moved in the unholding state of making the split claw 70 recede. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an excavation apparatus that excavates a large-diameter (for example, 1000 to 3000 mmφ) excavating casing while pushing it into the ground.

The excavation apparatus described in Patent Document 1 moves forward and backward toward a gripping casing in which gripped portions are formed at appropriate intervals along the longitudinal direction on the outer peripheral surface side, and toward the gripped portion of the drilling casing. A chuck device provided with a split claw, and a rotary pushing device that rotates the chuck device in a gripping state in which the split claw is advanced and moves the chuck device up and down at a stroke corresponding to the interval. . This excavating apparatus excavates a chuck apparatus that holds a gripped portion of a casing for excavation while rotating the chuck apparatus with a rotary push-in apparatus for a predetermined stroke, and then stops the rotation and push-in and stops the chuck apparatus in a non-gripping state. By alternately repeating a non-excavation operation for lifting a predetermined stroke outside the casing and moving to the next excavation operation, the excavation casing is intermittently pushed into the ground every predetermined stroke for excavation.
No. 8-9271

  However, in the excavator, as the excavation progresses, the resistance due to earth pressure when the excavation casing is rotated while being pushed in gradually increases. A large and large rotary pusher is required. As a result, the excavation apparatus has a problem that the manufacturing cost increases due to the increase in the size of the rotary pushing device, and the running cost increases to obtain a large output of the rotary pushing device.

  In order to solve the above-described problems, an object of the present invention is to provide an excavation apparatus that can reduce the size of a rotary pushing apparatus as compared with the conventional one.

  In order to reduce the size of the rotary pushing device as compared with the conventional one, the means adopted by the present invention as claimed in claim 1 is an excavation casing in which gripped portions are formed at appropriate intervals along the longitudinal direction on the outer peripheral surface side. The chuck device provided with the split claw that moves forward and backward toward the gripped portion of the excavation casing, the chuck device in the gripped state that advances the split claw, and the stroke corresponding to the interval are rotated. In the excavator provided with a rotary pushing device that moves up and down at a plurality of times, the excavation casing moves up and down in a non-gripping state in which a plurality of earth and sand agitation protrusions projecting from the outer peripheral surface of the excavation casing are retracted by the divided claws The excavator is provided so as not to collide with the chuck device.

  In order to prevent slippage of the chuck device with respect to the excavation casing so that the excavation casing can be pushed in while being reliably rotated, the means employed by the present invention according to claim 2 is characterized in that the excavation casing includes an inner cylinder and The two cylinders are connected by a rib disposed between the outer cylinder, the gripped portion is formed by a recess penetrating a part of the outer cylinder, and the earth and sand agitation protrusion protrudes from the recess. 2. The excavator according to claim 1, wherein the division claw of the chuck device is provided with an avoidance portion for avoiding a collision with the earth and sand agitation protrusion and a convex portion that fits into the corresponding concave portion. It is.

  In the excavating apparatus according to the present invention of claim 1, the earth and sand agitation protrusion of the excavation casing during excavation rotation stirs the earth and sand in contact with the outer peripheral surface of the excavation casing to make it a fluid and soft state. The outer peripheral surface of the excavation casing becomes slippery with respect to the inner peripheral surface of the underground excavation hole, and the rotational force and the pushing force required to push the excavation casing while rotating can be reduced as compared with the conventional case. As a result, the excavator according to the present invention can employ a small rotary pusher that requires a smaller output than the conventional rotary pusher, and can reduce the manufacturing cost and running cost of the rotary pusher. it can.

  In the excavating apparatus according to the second aspect of the present invention, since the convex portion of the split claw is fitted into the concave portion provided in the gripped portion of the excavation casing, the rotation direction and the pushing direction between the split claw and the gripped portion. Even if slip occurs, the convex part of the split claw is engaged with the concave part of the gripped part, so that there is no slip and a large rotational force and pushing force are transmitted to the excavation casing, so that reliable excavation can be performed.

  An excavator according to the present invention (hereinafter referred to as “the present excavator”) will be described with reference to the drawings showing an embodiment.

(First embodiment)
1 to 7 show a first embodiment of the excavator of the present invention. FIG. 1 is a perspective view showing the whole of the excavator of the present invention, with the main part cut away. FIG. 2 is an enlarged perspective view in which a main part of the excavator of the present invention is broken and enlarged. FIG. 3 is an enlarged front cross-sectional view showing a gripping state of the chuck device in the excavator of the present invention. FIG. 4 is an enlarged front cross-sectional view showing a non-gripping state of the chuck device in the excavator of the present invention. 5 is a cross-sectional view taken along line AA shown in FIG. FIG. 6 is a perspective view of the division claw of the excavator of the present invention. FIG. 7 is a front sectional view showing the entire excavator of the present invention during excavation.

  As shown in FIG. 1, the excavation apparatus 10 of the present invention includes an excavation casing 20, a chuck device 60 that holds the excavation casing 20, and a rotary push-in device 35 that pushes the chuck device 60 while rotating it. Yes. The excavating apparatus 10 according to the present invention includes an excavating operation in which a chuck device 60 that grips the gripped portion 31 of the excavating casing 20 is rotated by a rotary pushing device 35 and is pushed in for a predetermined stroke, and thereafter, the rotation and pushing are stopped and the gripping is not performed. By alternately repeating a non-excavation operation for lifting the chuck device 60 in a state outside the excavation casing 20 by a predetermined stroke and moving to the next excavation operation, the excavation casing 20 is intermittently inserted into the ground every predetermined stroke. Press to drill.

  The excavation casing 20 includes two types, a drilling casing 21 in which an excavating blade 26 (see FIG. 7) is provided at the opening periphery of the tip (lower end), and an extension casing (not shown). When deeply excavating the underground 1, the vertical dimension of the entire excavating casing 20 is extended by adding an appropriate number of the extending casings above the drilling casing 21. (Hereinafter, “excavation casing 20” refers to two types of drilling 21 and extension.)

  As shown in FIG. 1, the excavation casing 20 is provided with a plurality of earth and sand stirring protrusions 28 (protrusions 29 and protrusions 30) that protrude outward from the outer peripheral surface 20 a. These earth and sand agitation projections 28 agitate the earth and sand in contact with the outer peripheral surface 20a during excavation rotation, and collide with a chuck device 60 that moves up and down in a non-gripping state in which the divided claw 70 is retracted, as will be described later. It is provided at a position where it is not allowed.

  As shown in FIG. 1, the excavating casing 20 is formed with a gripped portion 31 for gripping the chuck device 60 on the outer peripheral surface 20a side. The gripped portions 31 are arranged at intervals P along the longitudinal direction on the vertical lines Z that are separated at intervals W along the circumferential direction of the outer peripheral surface 20a. This interval W is a dimension corresponding to the arrangement interval in the circumferential direction of the divided claws 70, 70... Provided in the chuck device 60. Further, the dimensions of the intervals P, P... Are the same as the dimensions corresponding to the vertical stroke of the lifting device 40 of the rotary push-in device 35, and in this example, they are equally spaced.

  The gripped portion 31 formed in the excavating casing 20 includes a recess 25, a gripped region 20 b formed on the outer peripheral surface 20 a and serving as a periphery of the opening 25 b of the recess 25, and an opening 25 b from the bottom surface 25 a of the recess 25. The projection 30 protrudes outward from the outer peripheral surface 20a. The recesses 25 and the protrusions 30 are arranged on the perpendicular line Z.

  In the excavation casing 20, the gripped portions 31 and the regions 20 c sandwiched between the upper and lower gripped portions 31 and 31 are alternately formed on each vertical line Z, and between the adjacent vertical lines Z and Z. Thus, a non-passing region 20d is formed along the vertical longitudinal direction at the outer peripheral surface 20a excluding the gripped portion 31 and the region 20c, so that the divided claw 70 does not rise and pass outside the non-passing region 20d during the non-excavation operation. It has become. The non-passing region 20d is provided with a projection 29 that protrudes by a size that does not collide with the inside of the chuck device 60.

  In this example, the gripped portion 31 that grips the chuck device 60 first (in this example, the gripped portion 31 at the lowermost end shown in FIG. 7) and the non-passing region 20d having the same height as The provision of the earth and sand agitation protrusions 28 (protrusions 30 and 29) that obstruct the gripping is omitted, so that the suspended excavation casing 20 and the gripped portion 31 of the chuck device 60 are relatively moved. The position alignment operation performed by rotating can be performed smoothly.

  As shown in FIG. 3, the excavating casing 20 is arranged by welding a plurality of ribs 24, 24... Between the outer peripheral surface of the inner cylinder 22 and the inner peripheral surface of the outer cylinder 23 in this example. It is installed. The concave portion 25 is formed by penetrating a part of the outer cylinder 23, and a connection collecting wall portion 34 (see also FIG. 5) having a square cross section in an opening portion between the inner cylinder 22 and the outer cylinder 23. It is arranged and welded to the inner cylinder 22 and the outer cylinder 23. The protrusion 30 is formed by welding a bar or the like to the outer peripheral surface of the inner cylinder 22 that becomes the bottom surface 25 a of the recess 25. In the manufacturing process of the casing 20 for excavation, since the operation | work which forms the recessed part 25 and the operation | work which makes the protrusion 30 for earth and sand stirring project from the recessed part 25 can be performed in parallel, reduction of manufacturing cost can be aimed at. .

  As shown in FIG. 1, the chuck devices 60 for gripping the excavation casing 20 are distributed at equal intervals in the circumferential direction so as to correspond to the interval W around the arrangement space S in which the excavation casing 20 is arranged. Are provided with a claw driving portion 59 for moving the divided claw 70, 70... Toward and away from the gripped portion 31 of the excavating casing 20.

  As shown in FIG. 6, the divided claw 70 includes an upper connecting portion 71, an outer sliding portion 72, an inner gripping region 73, convex portions 74 and 74, and an avoiding portion 75. The convex portions 74, 74 protrude from the gripping region 73 toward the arrangement space S side. The avoiding portion 75 extends from the upper surface 70b to the lower surface 70c, and is formed in a groove shape that is appropriately recessed in the depth dimension from the gripping region 73. Thus, when the avoidance portion 75 moves forward and backward from the gripping state to the non-griping state, The projection 30 is passed to avoid a collision. In the split claw 70 of this example, since the protrusion 30 is provided in the center of the concave portion 25 of the gripped portion 31, the avoidance portion 75 is formed in the center and the convex portions 74 and 74 are formed on both sides of the avoidance portion 75. Although not shown in the drawings, when the projection 30 of the gripped portion 31 is provided on one side of the concave portion 25, the avoiding portion 75 is formed on one side in the circumferential direction and the other side is convex. There is also a form in which the portion 74 is formed.

  The claw driving unit 59 is configured to divide the divided claws 70, 70... Into an outside standby position O (see FIG. 4) that does not grasp the grasped part 31 and an inside grasping position I (see FIG. 3) that grasps the grasped part 31. ). As shown in FIG. 2, the claw driving unit 59 includes a support device 61 that suspends and supports each divided claw 70 from above, and a holding device 62 that holds the lower side of each divided claw 70 slidably up and down. .

  The support device 61 includes a lower ring 66 that swingably supports the connecting portion 71 of the split claw 70 via a link mechanism 67, an upper ring 64 that rotatably supports the lower ring 66 via a bearing 65, and an upper The chuck cylinder 63 is configured to support the ring 64 from below and move up and down.

  The holding device 62 includes a cone ring 69 that is rotatably connected to the inside of the rotating device 50 via a bearing 68. This cone ring 69 is formed with claw holders 69b, 69b,... For holding the claw 70, 70... Slidably up and down, and the claw holders 69b, 69b. The sliding part 72 of the claw 70 is slidable, and a sliding part 69a having an inclined surface is formed so that the inner diameter continuously increases toward the upper side.

  In order to advance each divided claw 70 to the gripping position I as shown in FIG. 3, the excavating apparatus 10 of the present invention first contracts the chuck cylinder 63 and lowers the divided claw 70 together with the entire support device 61. Then, the division nail | claw 70 slides along the inclination direction of the sliding part 69a. When each of the divided claws 70 is advanced to the gripping position I where the gripping region 73 comes into contact with the gripped region 20b of the gripped portion 31, the contraction of the chuck cylinder 63 is stopped.

  At this gripping position I, as shown in FIG. 5, the convex portions 74 and 74 are fitted into the concave portion 25 to form the circumferential gaps a1 and a2, and the protrusion 30 is fitted into the avoiding portion 75 and the circumferential gap b1 and b2 are formed. In this example, the gap b1 or the gap b2 is larger than the sum of the gap a1 and the gap a2 (b1> a1 + a2 and b1> a1 + a2 hold), so when the casing 20 is rotated The outer side surface 74a of the convex portion 74 and the collecting wall 34 of the concave portion 25 are brought into surface contact with each other to prevent the casing 20 from sliding in the circumferential direction, and the inner side surface 75a of the avoiding portion 75 does not collide with the protrusion 30. ing. Further, when the casing 20 is pushed in, the lower end surfaces 74b, 74b of the convex portions 74, 74 and the collecting wall 34 of the concave portion 25 come into surface contact so that the casing 20 slides upward with respect to the divided claw 70. Lock. Therefore, the excavation apparatus 10 of the present invention can reliably excavate by transmitting a large rotational force and pushing force to the excavation casing 20 during the excavation rotation.

  On the other hand, in order to retract the divided claw 70 to the standby position O as shown in FIG. 4, first, the chuck cylinder 63 is extended, and the divided claw 70 is raised together with the entire support device 61. Then, the division claw 70 slides back along the inclination direction of the sliding part 69a. When the split claw 70 is retracted to the standby position O, the extension of the chuck cylinder 63 is stopped. At the standby position O, the tips of the convex portions 74 and 74 are in a state of being outside the opening 25b of the concave portion 25.

  The aforementioned rotary push-in device 35 for rotationally pushing the chuck device 60 rotates the chuck device 60 in the gripping state, and the chuck device 60 together with the rotary device 50 at a stroke corresponding to the intervals P, P. And a lifting device 40 that moves up and down.

  As shown in FIGS. 1 and 2, the rotating device 50 includes an annular thrust frame 51 supported by the elevating device 40, and a large-diameter gear built in the thrust frame 51 and provided outside the cone ring 69. The pinion gears 52, 52... Meshed with 69c and the rotation motors 53, 53.

  In order to rotate the chuck device 60 with the rotating device 50, the rotating motor 53 is activated to transmit the rotational force to the large-diameter gear 69 c of the cone ring 69 through the pinion gear 52. Then, the parts (split claw 70, link mechanism 67, and lower ring 66) rotatably supported by bearings 65 and 68 together with cone ring 69 rotate.

  As shown in FIG. 1, the elevating device 40 is connected to the thrust frame 51 and extends and contracts thrust cylinders 43, 43..., A thrust base 43 provided on the upper surface, and a ground 42. It is comprised with the horizontal jacks 41, 41 ... which support the base | substrate 42. As shown in FIG. The elevating device 40 can move the chuck device 60 up and down together with the rotating device 50 by the stroke by expanding and contracting the thrust cylinder 43.

Excavation of the underground 1 by the excavator 10 of the present invention will be described by taking as an example the case of removing the existing pile 2 shown in FIG.
(1) 1st process (casing arrangement | positioning process): First, the pile head 2a is exposed by removing the earth and sand above the existing pile 2. FIG. Subsequently, the excavator 10 of the present invention is installed on the ground such that the arrangement space S is located directly above the pile 2, and the chuck device 60 is brought into a non-gripping state. Next, the excavating casing 20 is lowered while being suspended by a crane or the like (not shown), and is inserted into the arrangement space S from above, and the pile head 2 a is externally fitted on the lower end side of the casing 20.

  (2) 2nd process (positioning process of division claw): Waiting outside the portion to be grasped 31 by moving the casing 20 up and down with a crane or rotating the chuck device 60 with the rotating device 50 The division claw 70 is aligned with the position O. The excavator 10 of the present invention includes a gripped portion 31 that grips the chuck device 60 in the initial stage of excavation (in this example, the gripped portion 31 at the lowermost end shown in FIG. 7), and a non-passing region 20d having the same height. Since the projections 28 are not provided, the divided claw 70 does not collide with the projections 28 even when the division claw 70 is rotated all around by the rotating device 50 at the time of the above alignment. I can work.

  (3) Third step (first step of shifting to the gripping state of the chuck device): Subsequently, as described above, the chuck cylinder 63 is contracted and the divided claw 70 is advanced to the gripping position I, and then the chuck The cylinder 63 is stopped.

  (4) Fourth step (casing rotation step): With the chuck device 60 held, the rotation motor 53 is started to rotate the excavation casing 20 as described above.

  (5) Fifth step (casing rotation pushing step): With the excavating casing 20 rotated, as described above, the lifting device 40 and the rotating device 50 together with the rotating device 50 lower the chuck device 60 corresponding to the interval P. Let Accordingly, the casing 20 is excavated while rotating the underground 1 with the excavating blade 26 and is pushed into the underground 1 by the stroke. During the excavation rotation, the earth and sand agitation protrusion 28 agitates the earth and sand in contact with the outer peripheral surface 20a to make it soft and fluid, and the excavation casing 20 has an inner peripheral surface of the underground excavation hole 1a. The outer peripheral surface 20a is made slippery. Further, since the convex portions 74 and 74 are fitted in the concave portion 25, the excavation rotation of the split claw 70 with respect to the casing 20 is stopped during excavation rotation, so that the excavation casing 20 is surely secured. Can be rotated and pushed.

  (6) Sixth step (step of shifting the chuck device to the non-gripping state): When the rotation pushing step of the fifth step is completed, the rotation motor 53 is stopped and the rotation of the excavating casing 20 is stopped. Subsequently, as described above, the chuck cylinder 63 is extended, and the split claw 70 is retracted to the standby position O as shown in FIG. 4, and when the standby position O is reached, the chuck cylinder 63 is stopped.

  (7) Seventh step (chuck device raising step): The chuck device 60 is lifted by a stroke corresponding to the interval P by the elevating device 40 as described above while the chuck device 60 is kept in the non-gripping state. At this time, the division claw 70 of the chuck device 60 rises outside the perpendicular line Z.

  (8) Eighth step (transition step to the gripping state of the chuck device after the seventh step): Subsequently, the chuck cylinder 63 is contracted as described above, and the divided claw 70 is held at the gripping position I as shown in FIG. Then, the chuck cylinder 63 is stopped. In the excavator 10 of the present invention, since the avoiding portion 75 is formed in the divided claw 70, the divided claw 70 can be prevented from colliding with the protrusion 30 in the eighth step.

  (9) Ninth step (repetition step / casing addition step): When the eighth step is completed, the above-mentioned fourth step, fifth step, sixth step, seventh step and eighth step are repeated as appropriate in this order. By repeating, the casing 20 for excavation is made to reach a desired depth. In addition, when the vertical dimension of the excavation casing 20 is insufficient in the seventh step while repeating, the extension casing (not shown) is connected to the casing 20 and extended to the ground 1 of the casing 20. You can continue pushing.

  (10) Tenth step (step after reaching the desired depth): When the tip of the casing 20 reaches the desired depth, the pile 2 inside the casing 20 is pulled out with a crane or the like while being cut into a length that can be lifted, Furthermore, the casing 20 is also pulled out from the ground 1 to complete the removal of the pile 2. If necessary, an operation of backfilling earth and sand in the excavation hole 1a extracted from the pile 2 may be added.

  As described above, the excavation apparatus 10 of the present invention makes the earth and sand agitation projection 28 agitate the earth and sand that is in contact with the outer peripheral surface 20a during excavation rotation (fifth step) to make it soft and fluid. The outer peripheral surface 20a of the excavating casing 20 becomes slippery with respect to the inner peripheral surface of one excavation hole 1a, and the rotational force and the pushing force required to push the excavating casing 20 while rotating are reduced as compared with the conventional one. it can. As a result, the excavator 10 of the present invention can employ a small rotary pusher 35 that requires a smaller output than the conventional rotary pusher, thereby reducing the manufacturing cost and running cost of the rotary pusher 35. Can do.

  In addition, in this example, although the aspect of removal of the existing pile 2 by this invention excavation apparatus 10 was illustrated, there also exists an aspect which newly installs a pile by this invention excavation apparatus 10. FIG. In the new construction of the pile, first, the excavation device 10 of the present invention is installed above the planned construction place of the pile, and then the casing 20 is placed in the ground 1 at a desired depth following the above-described second to ninth steps. Then, the underground pile is formed by, for example, placing concrete in the excavation hole formed by removing the earth and sand inside the casing 20.

(Second Embodiment)
FIG. 8 shows a second embodiment of the excavator of the present invention, and FIG. 8 (A) is a front sectional view showing the main part of the excavator of the present invention, in which the chuck device is held. is there. FIG. (B) is an exploded perspective view with the main part cut away. The excavation apparatus 80 according to the present embodiment is greatly different from the excavation apparatus 10 according to the first embodiment in that the claw 81 is provided in the chuck device 60 so as to advance and retract horizontally. .

  The division claw 81 is supported so that the lower part thereof can be horizontally advanced or retreated inward or outward by the holding part 89a of the support ring 89, and the rear side thereof is inclined so as to continuously increase in diameter toward the upper side. A sliding portion 82 made of an inclined surface is formed. In addition, an avoiding portion 90 such as a round hole is provided inside the divided claw 81 so as to avoid the collision by avoiding the protrusion 30. The sliding portion 82 includes projecting portions 83 and 83 projecting in the circumferential direction at both ends thereof.

  A pressing portion 85 that presses the divided claw 81 from above is provided below the lower ring 66. The pressing portion 85 is formed with a sliding portion 86 that slides on the front side (inner side) with the sliding portion 82, and the sliding portion 86 has rails 87 corresponding to the protruding portions 83, 83 at both ends thereof. , 87.

  In the excavator 80 of the present invention, in order to place the divided claw 81 in the gripping state, the chuck cylinder 63 is contracted to lower the pressing portion 85, and the sliding portion 82 is pressed and slid by the sliding portion 86. Thereby, the division nail | claw 81 advances horizontally toward an inner side. When the split claw 81 comes into contact with the casing 20 and the chuck device 60 is in a gripping state, the chuck cylinder 63 is stopped. At this time, the convex portions 74 and 74 of each divided claw 81 are horizontally fitted into the concave portion 25 of the grasped portion 31, and the protrusion 28 enters the avoiding portion 90 horizontally.

  On the other hand, in order to bring the split claw 81 into a non-gripping state, the chuck cylinder 63 is extended to raise the pressing portion 85, and the rails 87, 87 and the protruding portions 83, 83 are slid. Thereby, the division nail | claw 81 retreats horizontally toward an outer side. When the opening of the avoidance portion 90 comes out of the tip of the protrusion 30, the chuck cylinder is stopped.

  The configuration other than the above differences is substantially the same as that of the excavator 10 of the present invention in the first embodiment, and is the same as the excavator 10 of the present invention in the first embodiment among the reference numerals shown in FIG. The code | symbol has shown the same member.

1 shows a first embodiment of the excavator of the present invention, and is a perspective view showing the entirety of the excavator of the present invention, with a main part being broken away. In the same embodiment, it is the expansion perspective view which fractured | ruptured and expanded the principal part of this invention excavation apparatus. In the same embodiment, it is front sectional drawing which expands and shows the holding | grip state of the chuck apparatus in this excavation apparatus. In the same embodiment, it is front sectional drawing which expands and shows the non-gripping state of the chuck | zipper apparatus in this excavation apparatus. FIG. 4 is a cross-sectional view taken along line AA shown in FIG. 3 in the same embodiment. In the same embodiment, it is a perspective view which shows the division | segmentation nail | claw of this invention excavation apparatus. In the same embodiment, it is the front sectional view showing the whole excavation device of the present invention during excavation. 2 shows a second embodiment of the excavator of the present invention, FIG. (A) is a front sectional view showing the main part of the excavator of the present invention, the chuck device is in a gripping state, FIG. (B) is an exploded perspective view with the main part cut away.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Excavator of this invention 20 ... Casing for excavation
20a ... outer peripheral surface 31 ... gripped portion rotation pushing device ... 35 chuck device ... 60
70: Dividing claw 28 ... Sediment agitation protrusion P ... Interval

Claims (2)

  Excavation casing having gripped portions formed at appropriate intervals along the longitudinal direction on the outer peripheral surface side, a chuck device provided with split claws that move forward and backward toward the gripped portion of the excavation casing, and split claws The excavation casing includes a rotary pushing device that rotates the chuck device in a gripping state in which the chuck device is advanced and moves the chuck device up and down at a stroke corresponding to the interval. A plurality of earth and sand agitation protrusions are provided so as not to collide with the chuck device that moves up and down in a non-gripping state in which the divided claws are retracted. The casing for excavation is formed by connecting both cylinders with a rib disposed between an inner cylinder and an outer cylinder, and the gripped portion is formed by a recess penetrating a part of the outer cylinder, and Sediment agitation protrusions project from the recesses, and the split claw of the chuck device is provided with an avoidance part that avoids collision with the earth and sand agitation protrusions, and a projection that fits into the corresponding recesses. The excavator according to claim 1.