JP2010281125A - Bottom-enlarging excavation bucket and method for constructing bottom-enlarging part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bottom-enlarging excavation bucket capable of excavating a pile hole having a high bottom-enlargement ratio and shortening the length in a vertical direction. <P>SOLUTION: By connecting a lower link member 43 of a parallel movement link part 40L of a parallel movement link mechanism 40 to a second elevating and lowering frame 30 via a second connecting link member 41, the amount of vertical movement of a first elevating and lowering frame 20 is made larger than the amount of vertical extension and contraction of a hydraulic cylinder 60. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bottom expansion excavation bucket used for forming a pile hole for placing a foundation pile of a building and a method for constructing a bottom expansion portion of a pile hole using the bottom expansion excavation bucket.

  In recent years, there has been a demand for higher-rise buildings and enhanced earthquake resistance. For foundation piles, large-diameter bottomed piles with excellent vertical support performance and pull-out resistance performance are used.

  The expanded bottom pile is made of concrete reinforced with reinforcing bars, and is composed of a shaft portion and an expanded bottom portion located at the lowermost portion thereof. One of the parameters indicating the performance of the expanded bottom pile is a bottom expansion rate, which is indicated by dividing the area of the diameter obtained by subtracting 100 mm from the outer diameter of the expanded bottom portion by the area of the shaft diameter. A large bottom expansion rate means that the bottom expansion portion is larger than the shaft portion, which contributes to the performance improvement of the bottom expansion pile. The pile hole for placing this bottomed pile is, for example, excavating the ground with a drilling bucket attached to an earth drilling machine to form the shaft part, and then changing the bottom bottom excavation bucket to the bottom of the shaft part The bottom expanded part is formed by excavating the outer side in the radial direction.

  Conventionally, various bottomed excavation buckets are known as devices for forming a bottomed portion of a pile hole (for example, refer to Patent Documents 1 and 2). In these bottoming excavation buckets, the outer diameter of the bottom expansion bucket body is expanded or reduced using a hydraulic cylinder, and in order to increase the bottom expansion rate, it is necessary to secure a large expansion / contraction amount of the hydraulic cylinder. is there.

JP 58-222287 A JP-A-60-242292

  However, the excavator such as an earth drill machine has a height that can lift a drilling bucket or a bottom-excavated excavation bucket from the ground surface depending on the model, but when placing a bottom-extended pile with a large bottom expansion rate, There is a problem that it is necessary to use a large-sized bottom-excavation bucket, and the height of the bottom-excavation bucket is high, so that an excavator of a model with a low lifting height cannot be used.

  In the bucket for deep bottom excavation of Patent Document 1, since the hydraulic cylinder is arranged at the upper end portion of the link mechanism so as to extend upward, there is a problem that the length in the vertical direction becomes long. In the bucket for bottomed excavation of Patent Document 2, the hydraulic cylinder is disposed inside the outer cylinder and the inner cylinder, and the hydraulic cylinder extends in the axial direction of the outer cylinder and the inner cylinder. In order to increase the length, it is necessary to increase the length of the hydraulic cylinder. Therefore, similarly to Patent Document 1, there is a problem that the excavator of a model having a long vertical length and a low lifting height cannot be used.

  Therefore, if it is possible to excavate a pile hole with a large bottom expansion rate and develop a bottom expansion excavation bucket capable of shortening the vertical length, even an excavator of a model with a low lifting height can be used. The excavator can be used effectively.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a bottom-excavation bucket capable of excavating a pile hole having a large bottom expansion rate and capable of reducing the length in the vertical direction.

  In order to achieve the above object, the invention according to claim 1 is characterized in that the post extends in the vertical direction and is rotatable about the axis, and is attached to the outer periphery of the post and engaged with the post around the axis. A first lifting frame movable in the axial direction of the post, and attached to the outer periphery of the first lifting frame and movable in the axial direction of the post while being engaged with the first lifting frame around the axis. A second elevating frame, and a hydraulic cylinder connected to the first elevating frame and the second elevating frame to elevate and lower the second elevating frame relative to the first elevating frame by vertically extending and contracting And a translation link portion that is movable in the radial direction around the post is connected to the first lifting frame side, and a lower link member of the translation link portion is a first connection link member. The lower link member is connected to the second elevating frame via a second connection link member and is connected to the post. A translation link mechanism that increases the amount of vertical movement of the elevating frame, and an excavation that is attached to the outer end of the translation link portion and can be translated in the radial direction with respect to the post by the translation link portion. And a bucket for widening excavation characterized by comprising a main body for bucket.

  According to this invention, since the vertical movement amount of the first elevating frame is increased with respect to the vertical expansion / contraction amount of the hydraulic cylinder, even if the vertical length of the hydraulic cylinder is shortened, the first It is possible to ensure a large amount of movement in the radial direction of the excavation bucket body by the movement of the lifting frame.

  According to a second aspect of the present invention, in the bottom-excavation bucket according to the first aspect, the lower link member of the parallel movement link portion has a maximum load acting radially inward when the hydraulic cylinder is fully extended. The connection position with said 2nd connection link member is set so that it may become.

  According to a third aspect of the invention, in the bucket for expanding bottom excavation according to the first or second aspect, a space portion penetrating in the vertical direction is formed in the upper link member constituting the parallel movement link portion, The second connecting link member is swingably inserted into the space portion.

  According to a fourth aspect of the present invention, in the bucket for bottomed excavation according to any one of the first to third aspects, the excavation bucket body has a receiving plate extending in the horizontal direction for receiving the excavated earth and sand. It is characterized by that.

  The invention according to claim 5 is a method for constructing a bottom portion of a pile hole using the bottom-excavated bucket of claim 1, wherein the outer diameter of the excavation bucket body is smaller than the inner diameter of the shaft portion of the pile hole. In this state, the bottomed excavation bucket is moved toward the bottom of the pile hole, and then the excavation bucket body of the bottomed excavation bucket is moved radially outward to move the bottomed excavation bucket. A bottom expansion construction method characterized in that a bottom expansion portion having an inner diameter larger than the inner diameter of the shaft portion is formed by moving it upward or downward.

  According to the inventions of claims 1 and 5, since it is possible to reduce the height in the vertical direction of the bottomed excavation bucket while ensuring a large amount of movement in the radial direction of the excavation bucket body, Even if it is an excavator of a model with a low lifting height, the bucket for bottom expansion excavation which has the capability of excavating a pile hole with a large bottom expansion ratio can be used. Thereby, while being able to ease the constraint conditions regarding the excavation work of the pile hole, it is possible to increase the utility value of the type of excavator having a low lifting height.

  Further, since the hydraulic cylinder is connected to the first elevating frame and the second elevating frame, the hydraulic cylinder expands and contracts in parallel with the axis of the post, and swings in the radial direction with respect to the post. It doesn't move. Therefore, the posture of the hydraulic cylinder is not affected by the movement of the parallel movement link mechanism, and interference between the hydraulic cylinder and the shaft portion of the pile hole can be reliably prevented.

  According to the second aspect of the present invention, the lower link member of the translation link portion is connected to the second connection link member so that the load acting radially inward when the hydraulic cylinder is fully extended is maximized. Since the connection position is set, the earth and sand taken inside the bucket main body for excavation can be compressed with a big load. Here, since the hydraulic pressure acts on the entire surface of the piston when the hydraulic cylinder is extended, the driving force can be larger than that when the hydraulic cylinder is contracted when the hydraulic cylinder is extended. As a result, even if more soil and sand from excavation is taken into the inside of the excavation bucket body, it is possible to reduce the diameter of the expanded excavation bucket more reliably than the inner diameter of the shaft portion of the pile hole and The bucket can be lifted to the ground side through the shaft portion of the pile hole.

  According to the third aspect of the present invention, since the plate-like second connecting link member is swingably inserted into the space portion penetrating in the vertical direction of the upper link member, the parallel movement link portion is made compact. It becomes possible to do. As a result, it is possible to reduce the weight of the bottom-excavation bucket and to increase the amount of earth and sand taken after excavation by the bottom-excavation bucket.

  According to the fourth aspect of the present invention, the excavation bucket body has a receiving plate extending in the horizontal direction for receiving the excavated earth and sand, so that it can be opened and closed as in the prior art. This can contribute to lowering the lifting height of the excavator. That is, since the earth and sand received by the backing plate can be discharged outward by centrifugal force due to rotation around the shaft center of the bottom-excavated excavation bucket, the earth and sand from the excavation bucket body without providing an openable bottom cover Can be discharged.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective front view showing an operation state of a bottom-excavation bucket according to an embodiment of the present invention, in which a left side shows a reduced diameter state and a right side is a transparent front view showing a diameter expanded state. It is sectional drawing which shows the excavation state of the bottom expanded part of a pile hole using the bucket for bottom expanded excavation of FIG. It is a see-through | perspective front view which shows the diameter-reduced state of the bucket for wide bottom excavation of FIG. It is a see-through | perspective front view which shows the diameter expansion state of the bucket for expanded bottom excavation of FIG. It is sectional drawing which follows the WW line of FIG. It is sectional drawing which follows the XX line of FIG. It is sectional drawing which follows the YY line of FIG. FIG. 2 is an enlarged plan view of an upper link member in the parallel movement link mechanism of FIG. 1. It is a front view of the upper side link member of FIG. It is sectional drawing of the upper side link member of FIG. It is a top view of the 2nd raising / lowering frame in FIG. It is a front view of the bucket main body for excavation in FIG. It is a front view which shows the attachment state of the hydraulic cylinder of FIG. It is a top view which shows the diameter-reduced state of the bucket for wide bottom excavation of FIG. It is a top view which shows the diameter expansion state of the bucket for wide bottom excavation of FIG. It is a schematic diagram which shows the motion of the link member in the parallel displacement link mechanism of FIG. It is a schematic diagram which shows the operation | movement relationship between the lower side link member and the 2nd connection link member in the parallel displacement link mechanism of FIG. It is a front view which shows transition of operation | movement of the parallel displacement link mechanism of FIG. 1, Comprising: (a)-(e) is a front view which shows transition from a diameter-reduced state to a diameter-expanded state. It is sectional drawing which shows the process in which the pile hole of FIG. 1 is formed, Comprising: (a)-(d) is sectional drawing which shows transition until the bottom expansion part of a pile hole is formed.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 18 show an embodiment of the present invention. FIG. 2 shows a state of excavation of the pile hole 100 by the earth drill 1 as an excavator. The earth drill machine 1 includes a traveling unit 2, a boom 3, a support beam 4, a rotation drive unit 5, a kelly bar (rotation drive shaft) 6, and the like. The traveling unit 2 is capable of traveling on the ground surface G and supports the lower end portion of the boom 3 that extends obliquely upward. The kelly bar 6 is suspended via a rope 8 that extends downward from the tip of the boom 3. The kelly bar 6 is movable in the vertical direction by winding or unwinding the rope 8 by a drum (not shown) provided on the traveling unit 2 side. At the tip of the support beam 4 connected to the traveling unit 2, there is provided a rotation drive unit 5 that rotates the kelly bar 6 about its axis. A plurality of reels 7 for winding a hydraulic hose, an electric control cable, and the like are provided in the vicinity of the lower side of the rotation drive unit 5. An expanded bottom excavation bucket 10 for forming the expanded bottom portion 102 at the bottom of the pile hole 100 is attached to the lower end portion of the kelly bar 6.

  FIG. 1 shows details of the bottom excavation bucket 10 of FIG. The bottomed excavation bucket 10 mainly includes a post 11, a first lifting frame 20, a second lifting frame 30, a parallel movement link mechanism 40, a hydraulic cylinder 60, a drilling bucket body 70, and a stabilizer 80. I have. The post 11 extends in the vertical direction, and an upper end portion thereof can be connected to a lower end portion of the kelly bar 6. The post 11 can enter the pile hole 100 by the lowering of the kelly bar 6. As shown in FIG. 5 and FIG. 11, the post 11 is formed in a pipe shape having a rectangular cross section over the entire length by joining four strip-shaped steel plates by welding. The outer peripheral surface of the post 11 is formed into a smooth flat surface by machining or the like. The reason why the cross-sectional shape of the post 11 is quadrangular is that the first elevating frame 20 is engaged with the post 11 about the axis P. A central bottom excavation plate 12 for excavating the bottom surface of the widened portion 102 is fixed to the lower end portion of the post 11. As shown in FIG. 15, the center bottom excavation plate 12 is formed in a rectangular shape having a planar shape extending outwardly about the axis P of the post 11. A bracket 13 to which one end portion of the first connection link member 46 of the parallel movement link mechanism 40 is connected is fixed immediately above the central bottom excavation plate 12 of the post 11.

  A first elevating frame 20 is attached to the outer periphery of the post 11. The first lifting frame 20 is movable in the axial direction of the post 11 while being engaged with the post 11 around the axis P. As shown in FIG. 5 and FIG. 11, the first elevating frame 20 is a frame main body 21 having a rectangular cross-sectional shape formed by joining four strip-shaped steel plates by welding in the same manner. have. The axial length of the frame body 21 is shorter than the overall length of the post 11. A liner 22 slidably contactable with the outer peripheral surface of the post 11 is attached to the inner peripheral surface side of the frame main body 21. The reason why the cross-sectional shape of the frame main body 21 is quadrangular is that the second elevating frame 30 is engaged with the first elevating frame 20 around the axis P in the same manner as described above. A link holding part 25 is fixed to the lower part of the frame body 21. The link holding part 25 has a function of swingably supporting the lower link member 43 and the upper link member 44 constituting the translation link part 40L of the translation link mechanism 40.

  As shown in FIG. 11, a second lifting frame 30 is attached to the outer periphery of the first lifting frame 20. The second lifting frame 30 has a cylindrical metal member 31 having a quadrangular cross-sectional shape. The second elevating frame 30 has a metal base 33 having an octagonal planar shape for fixing the cylindrical metal member 31. As shown in FIGS. 6 and 11, the cylindrical metal member 31 and the octagonal metal plate 33 are divided into two with a line passing through the axis P as a boundary. The cylindrical metal member 31 divided into two parts and the octagonal metal base 33 are integrated by fastening the fastening part 33a and the fastening part 33b with bolts 33c so as to sandwich the first lifting frame 20 from the outside. Yes. Thereby, the second lifting frame 30 is movable in the axial direction with respect to the first lifting frame 20 in a state of being engaged with the first lifting frame 20 around the axis P. As shown in FIG. 11, a liner 32 that is slidable in contact with the outer peripheral surface of the frame main body 21 in the first elevating frame 20 is attached to the inner peripheral surface side of the cylindrical metal member 31.

  A support fitting 23 is fixed to the upper end portion of the frame main body 21 of the first elevating frame 20. Four hydraulic cylinders 60 are held on the support fitting 23. As shown in FIG. 13, the hydraulic cylinder 60 is composed of a trunnion-type hydraulic cylinder in which the fulcrum portion 60b is located approximately at the center in the axial direction of the cylinder body 60a. The fulcrum part 60 b of the hydraulic cylinder 60 is fixed to the frame body 21 of the first elevating frame 20 via the support fitting 23. As shown in FIG. 13, the hydraulic cylinder 60 has a piston 61 in the cylinder body 60a, and the piston 61 can move in the axial direction by the pressure of hydraulic oil supplied from the earth drill machine 1 side. Yes. A rod 62 extending in the axial direction is connected to one of the pistons 61. The rod 62 protrudes from the cylinder body 60 a, and a connecting tool 63 is attached to the tip of the rod 62.

  The hydraulic cylinder 60 is configured such that the rod 62 extends when the hydraulic oil is pumped to the pipe 63a, and the rod 62 contracts when the hydraulic oil is pumped to the pipe 63b. Each connection tool 63 is connected to a support frame 34 fixed to the metal base 33 of the second lifting frame 30. Each hydraulic cylinder 60 has a function of moving the second lifting frame 30 up and down with respect to the first lifting frame 20 by the expansion and contraction of the rod 62 accompanying the movement of the piston 61. The hydraulic cylinder 60 has a position sensor 64 that detects the amount of movement of the piston 61. In this embodiment, the horizontal movement amount (expansion / contraction amount) of the excavation bucket body 70 can be indirectly measured by an electrical signal from the position sensor 64.

  Four sets of parallel movement link mechanisms 40 are arranged on the outer periphery of the first lifting frame 20. As shown in FIG. 1, each parallel movement link mechanism 40 has a parallel movement link portion 40 </ b> L that is connected to the link holding portion 25 of the first elevating frame 20 and can move in the radial direction about the post 11. Yes. The translation link portion 40L includes a lower link member 43, an upper link member 44, and a connection link member 45. One of the lower link members 43 is connected to the connecting portion D of the link holding portion 25. The upper link member 44 is positioned above the lower link member 43, and one of the upper link members 44 is connected to the connecting portion I of the link holding portion 25. The connecting link member 45 is a member that connects the connecting portion B of the lower link member 43 and the connecting portion K of the upper link member 43 so that the lower link member 43 and the upper link member 43 are parallel to each other. Thereby, the line which connects each connection part B, K, I, and D in the translation link part 40L comprises the parallelogram for translation.

  The connecting portion B of the lower link member 43 of the translational link portion 40L is connected to the connecting portion E of the holding bracket 13 fixed to the lower portion of the post 11 via the first connecting link member 46. A connecting bracket 42 is fixed to the lower link member 43, and a connecting portion A is formed on the upper portion of the connecting bracket 42. The connecting portion A of the connecting bracket 42 is connected to the connecting portion H of the metal base 33 of the second lifting frame 30 via the second connecting link member 41. In this embodiment, by connecting the connection bracket 42 fixed to the lower link member 43 in the translation link portion 40L to the second lifting frame 30 via the second connection link member 41, the first The vertical movement amount of the lifting / lowering frame 20 is made larger than the vertical expansion / contraction amount of the hydraulic cylinder 60. Thus, the parallel movement link mechanism 40 ensures a large amount of movement in the radial direction relative to the post 11 of the excavation bucket body 70 even if the vertical expansion / contraction amount (stroke) of the hydraulic cylinder 60 is set short. Is configured to be possible.

  Further, as shown in FIG. 17, the lower link member 43 of the parallel movement link portion 40L is a second connection link member so that the load P1 acting inward in the radial direction when the hydraulic cylinder 60 is fully extended is maximized. The position of the connecting part A with 41 is set. That is, when the hydraulic cylinder 60 is in its most contracted state, the distance between the connecting portion D that functions as a fulcrum and the connecting portion A that functions as a power point is set to L2. The distance between the connecting part D that functions and the connecting part A that functions as a power point is set to L1. Here, since the distance L1 is larger than the distance L2, the load P1 acting on the connecting portion C of the lower link member 43 in the state in which the hydraulic cylinder 60 is most extended is in the state in which the hydraulic cylinder 60 is most contracted. It becomes larger than the load P2 acting on the connecting portion C.

  8 to 10 show details of the upper link member 44. As shown in FIG. 8, the upper link member 44 has two metal plate-like members 44a, and the plate-like members 44a are arranged at a predetermined interval. Each plate-like member 44a has a connecting hole 44h constituting the connecting portion J at one end, and a connecting hole 44g constituting the connecting portion I at the other end. Spacers 44d, 44e, and 44f functioning as reinforcing materials are provided on the inner surface side of each plate member 44a. The spacer 44d is disposed in the vicinity of the connecting portion J of the plate-like member 44a. The spacer 44e is disposed so that the upper surface thereof coincides with the upper surface of the plate-like member 44a, and one end thereof is in contact with the spacer 44d. The spacer 44f is disposed obliquely so as to connect the lower end portion of the spacer 44d and the other end portion of the spacer 44e. The opposing plate-like members 44a are connected by welding via spacers 44d, 44e, and 44f.

  A fixing hole 44i is formed at substantially the center in the longitudinal direction of each plate member 44a, and a connecting pin 44b protruding outward is inserted into the fixing hole 44i. The connecting pin 44b is fixed to the plate member 44 by welding. In the upper link member 44, a space portion S penetrating in the vertical direction is formed by spacers 44d, 44e, and 44f provided between the respective plate-like members 44a. The second connecting link member 41 is inserted in the space S of the upper link member 44 so as to be swingable. As shown in FIG. 1, the second connecting link member 41 is connected to the metal base 33 of the second lifting frame 30 with the connecting portion H at the upper end thereof being inserted into the space S of the upper link member 44. The connecting portion A at the lower end is connected to a connecting bracket 42 fixed to the lower link member 43.

  As shown in FIGS. 14 and 15, the bottom-excavated excavation bucket 10 includes two sets of first excavation bucket bodies 70 and two sets of second excavation bucket bodies 70 ′. One first excavation bucket body 70 and the other first excavation bucket body 70 are disposed so as to face each other about the axis P. Similarly, the second excavation bucket body 70 ′ is also disposed so as to face each other about the axis P. The difference between the first excavation bucket body 70 and the second excavation bucket body 70 ′ is the presence or absence of a bottom surface excavator 76 for excavating the bottom surface of the bottom expanded portion 102. Only the bottom excavator 76 is attached.

  Each excavation bucket body 70, 70 ′ is connected to each parallel movement link mechanism 40 arranged around the post 11. As shown in FIG. 1, the connecting portion C of the lower link member 43 in the parallel movement link mechanism 40 is connected to a lower bracket 71 a provided on the inner surface of the excavator holding plate 71 of the excavation bucket body 70. Similarly, the connecting portion J of the upper link member 44 in the parallel movement link mechanism 40 is connected to an upper bracket 71 b provided on the inner surface of the excavator holding plate 71 of the excavation bucket body 70. As shown in FIG. 12, a notch 71 a for avoiding interference with the second connection link member 41 and the connection bracket 42 is formed on the upper portion of the excavator holding plate 71.

  As shown in FIGS. 14 and 15, an inner surface excavation tool 73 is attached to the tip of the excavation tool holding plate 71 of the excavation bucket body 70. The excavation bucket body 70 is formed with an arc wall 72 extending in an arc shape from the excavator holding plate 71. An end wall 75 extending to the axis P side is connected to the end of the arc wall 72. Below the excavation bucket body 70, a horizontally extending receiving plate 74 for receiving the excavated earth and sand is disposed. The receiving plate 74 is a lower end portion of the excavator holding plate 71, the arc wall 72, and the end wall 75. It is fixed to. A plurality of bottom surface excavating tools 76 are attached to the front end portion of the receiving plate 74 in the rotation direction in a row with a predetermined interval. An angle θ1 of the bottom excavation tool 76 with respect to a straight line passing through the axis P of the post 11 is set to 30 degrees.

  As shown in FIG. 15, the second excavation bucket body 70 ′ has a receiving plate 74 ′ that is slightly smaller in area than the receiving plate 74 of the first excavation bucket body 70. This is for avoiding interference with the central bottom excavation plate 12 when the diameter of the bottom-excavation excavation bucket 10 is reduced, as shown in FIG. Similarly to the first excavation bucket body 70, an arc wall 72 ′ and an end wall 75 ′ are formed in the second excavation bucket body 70 ′. In the second excavation bucket body 70 ′, since the area of the receiving plate 74 ′ is small, a part of the arc wall 72 ′ protrudes rearward from the end of the receiving plate 74 ′. .

  The center bottom excavation plate 12 shown in FIG. 15 is fixed to the lower end portion of the post 11 as described above, and can rotate about the axis P integrally with the post 11. The central bottom excavation plate 12 is provided with a plurality of central bottom excavation tools 12a. The center bottom excavation tool 12a is attached only to the end face side that is the leading portion of the center bottom excavation plate 12 with respect to the excavation direction F1. Each of the excavating tools 12a, 73, and 76 is adjusted in radial position and vertical position so that the entire inner surface of the bottom expanded portion 102 can be excavated uniformly.

  As shown in FIG. 4, a stabilizer 80 is provided at the upper end of the post 11. The stabilizer 80 can adjust the diameter of an outer peripheral surface so that it may become substantially the same as the internal diameter D1 of the axial part 101 of the pile hole 100. FIG. The stabilizer 80 suppresses the runout of the post 11 when the post 11 is rotated about the axis P by the earth drill 1 as an excavator, and is concentric with the shaft 101 of the pile hole 100. It becomes possible to excavate the expanded bottom portion 102 in a shape. The stabilizer 80 is connected to the post 11 via a connecting pin 80 c press-fitted into the post 11. A cylindrical connecting portion 80 a to which the tip end portion 6 a of the kelly bar 6 of the earth drill machine 1 can be fitted is attached to the upper surface plate 80 b of the stabilizer 80. A chain-like connecting member 6 b that can be connected to the upper surface plate 80 b of the stabilizer 80 is provided on the lower end side of the kelly bar 6 of the earth drill machine 1. Here, the vertical height H2 of the bottomed excavation bucket 10 means the distance from the bottom surface of the central bottom excavation plate 12 to the upper end surface of the connecting portion 80a of the stabilizer 80.

  In the earth drill machine 1 in this embodiment, it is possible to measure the depth of the bottomed excavation bucket 10 and the outer diameter of the excavation bucket body 70, and based on the measured depth data and the outer diameter measurement data. It is possible to form an enlarged bottom portion 102 having an arbitrary size at an arbitrary position of the pile hole 100. The amount of movement of the excavation bucket body 70 in the radial direction is indirectly measured by the position sensor 64 that detects the amount of expansion / contraction of the hydraulic cylinder 60 described above. Further, the depth measurement of the bottom-excavation bucket 10 is performed by, for example, a rotation amount detection sensor (not shown) that detects the winding amount of the rope 8 that suspends the kelly bar 6. The measurement depth data and the outer diameter measurement data are image-processed by a computer (not shown) provided in the cab of the earth drill machine 1 so that the excavation status can be grasped in the cab. Thereby, the operator of the earth drill machine 1 can excavate the pile hole 100 while looking at the screen showing the current excavation state displayed on the computer in the cab.

  Next, a procedure for excavating the pile hole 100 using the bucket 10 for expanding bottom excavation will be described.

  As shown to Fig.19 (a), the drilling bucket 90 attached to the earth drill machine 1 as an excavator is rotated around an axial center, and the drilling bucket 90 is moved from the ground surface G toward the ground, thereby making a pile. The hole 100 is excavated. Then, excavation by the drilling bucket 90 is terminated at a position advanced from the ground surface G by a predetermined depth. In this state, the inner diameter of the shaft portion 101 of the excavated pile hole 100 is D1. Here, before starting the excavation of the shaft portion 101, the stabilizing liquid W is supplied from the ground surface G side to the pile hole 100 in order to promote the removal of excavated earth and sand in the pile hole 100, prevent the ejection of groundwater, prevent the pile hole wall from collapsing, and the like. In. Next, as shown in FIG. 19 (b), the drilling bucket 90 is removed and replaced with the bottom-excavated bucket 10. Then, the bottom of the pile hole 100 is excavated by the bucket 10 for expanding bottom excavation.

  FIG. 19 (c) shows a state where the bottom expanded portion 102 is formed at the bottom of the pile hole 100. When the bottomed excavation bucket 10 is put into the pile hole 100, the outer diameter of the bottomed excavation bucket 10 is set to D3 due to the reduced diameter. Here, the outer diameter D <b> 3 is set slightly smaller than the inner diameter of the shaft portion 101. Next, with the outer diameter of the bottomed excavation bucket 10 set to D3, the bottomed excavation bucket 10 is lowered along the shaft portion 101 of the pile hole 100, and the bottomed excavation bucket 10 is landed on the bottom of the pile hole 100. Let Thereafter, as shown in FIG. 14, the bottom-excavated bucket 10 is rotated in the excavation direction F <b> 1 about the axis P, and excavation of the bottom-extended portion 102 is started. After the excavation is started, the diameter of the bottom-excavated bucket 10 is gradually increased by the contraction operation of the hydraulic cylinder 60.

  (A)-(e) of FIG. 18 has shown a mode that the bucket 10 for bottomed excavation transfers from a diameter-reduced state to a diameter-expanded state. When the diameter of the bottom-excavation bucket 10 is increased, hydraulic oil is pumped into the cylinder body 60a of the hydraulic cylinder 60 through the pipe 63b. As a result, the connector 63 attached to the tip of the rod 62 moves to the cylinder body 60 side, and the hydraulic cylinder 60 is contracted. Since the connecting tool 63 is connected to the metal base 33 of the second lifting frame 30, the hydraulic cylinder 60 is contracted to connect the connecting part G of the connecting tool 63 attached to the tip end of the rod 62 and the hydraulic cylinder 60. The fulcrum parts F will approach each other. As a result, the second connecting link member 41 is pushed down, and the lower link member 43 and the upper link member 44 constituting the parallel movement link portion 40L swing outward with respect to the link holding portion 25. As a result, the excavation bucket body 70 connected to the lower link member 43 and the upper link member 44 moves outward in the radial direction.

  FIG. 15 shows the excavation state of the expanded bottom portion 102 by the expanded bottom excavation bucket 10 in the diameter expanded state. Since the excavation bucket body 70 is provided with the inner surface excavation tool 73 and the bottom surface excavation tool 76, the inner surface and the bottom surface of the bottom expanded portion 102 are excavated simultaneously. Further, the central portion of the bottom surface of the expanded bottom portion 102 is excavated by an excavating tool 12 a attached to the central bottom excavation plate 12. As a result, an expanded bottom portion 102 having an inner diameter D2 is formed at the bottom of the pile hole 100. One of the parameters indicating the performance of the expanded pile is the expansion rate, which is indicated by dividing the area of the diameter obtained by subtracting 100 mm from the outer diameter D2 of the expanded bottom portion 102 by the area of the diameter D1 of the shaft portion 101. It is. When the bottom expansion rate is large, the bottom expansion portion 102 becomes larger than the shaft portion 101, which leads to an increase in performance of the bottom expansion pile.

  In this embodiment, the bottom expanded excavation bucket 10 in the expanded state located at the bottom of the pile hole 100 is gradually moved upward while rotating in the excavation direction F1, thereby expanding the bottom expanded portion 102 of any size. Can be formed. That is, since the operator of the earth drill machine 1 can perform excavation while looking at the image based on the measurement depth data and the outer diameter measurement data, the vertical position of the widening excavation bucket 10 and the radial position of the excavation bucket body 70 By adjusting this, it is possible to form the expanded bottom portion 102 having an arbitrary size.

  When excavation of the expanded bottom portion 102 is completed, hydraulic oil is pumped to the piping 63a of the hydraulic cylinder 60 of the expanded bottom excavation bucket 10, and the excavation bucket body 70 starts moving inward in the radial direction. That is, hydraulic oil is pumped to the piping 63a of the hydraulic cylinder 60 until the bottom-excavation bucket 10 is changed from the expanded diameter state of FIG. 18 (e) to the reduced diameter state of FIG. 18 (a). Based on the electrical signal from the position sensor 64 of the hydraulic cylinder 60, when it is determined that the bottom-excavated bucket 10 has completely reduced its diameter and has reached the outer diameter D <b> 3, the bottom-excavated bucket 10 is removed from the pile hole 100. Raised to G side.

  FIG. 19D shows a state where the bottom-excavated bucket 10 is pulled up from the pile hole 100 to the ground surface G side. When the bottomed excavation bucket 10 is pulled up to the ground surface G side, hydraulic oil is pumped to the pipe 63b of the hydraulic cylinder 60, and the diameter of the bottomed excavation bucket 10 is expanded again. Since the bottomed excavation bucket 10 holds the excavated earth and sand 110, the earth and sand 110 that has been held as the diameter of the bottomed excavation bucket 10 increases is discharged to the ground surface G side. In the state where the diameter of the bottomed excavation bucket 10 is expanded, the earth and sand 110 remains on the receiving plate 74 of the excavation bucket body 70, and therefore the bottomed excavation bucket 10 is rotated in the direction opposite to the excavation direction F1. Thus, the earth and sand 110 remaining on the upper surface of the receiving plate 74 can be discharged to the outside by centrifugal force.

  FIG. 16 shows the movement of the connecting portions A to F of the link members in the parallel movement link mechanism 40. As shown in FIG. 16, the vertical movement amount (line segment DD ′) of the first lifting frame 20 with respect to the vertical expansion / contraction amount (line segment G′F′−line segment GF) of the hydraulic cylinder 60 is compared. It can be seen that the vertical movement amount of the first lifting frame 20 is larger than the vertical expansion / contraction amount of the hydraulic cylinder 60. Further, the line segment FF ′ and the line segment GG ′ indicating the movement of the hydraulic cylinder 60 remain parallel to the axis P, and therefore the posture of the hydraulic cylinder 60 is determined by the movement of the parallel movement link mechanism 40. The interference between the hydraulic cylinder 60 and the shaft portion 101 of the pile hole 100 can be surely prevented.

  FIG. 17 shows an operational relationship between the lower link member 43 and the second connecting link member 41 in the parallel movement link mechanism 40. In a state where the hydraulic cylinder 60 is most contracted (in a state where the diameter of the bottom-excavation bucket 10 is expanded), the distance between the connecting portion D that functions as a fulcrum of the lower link member 43 and the connecting portion A that functions as a power point is L2. Yes. In the state where the hydraulic cylinder 60 is most extended (the diameter of the bottom-excavation bucket 10 is reduced), the distance between the connecting portion D that functions as a fulcrum of the lower link member 43 and the connecting portion A that functions as a power point is L1. It has become. Since the distance L1 is greater than the distance L2, the load P1 acting on the connecting portion C of the lower link member 43 in the reduced diameter state of the bottom-excavated bucket 10 is more likely to be applied to the connecting portion C in the expanded diameter state. Greater than P2.

  Thus, by adopting the structure of FIG. 17 for the parallel movement link mechanism 40, the earth and sand 110 taken inside the bucket main body 70 for excavation can be compressed with the big load P1. Further, since the hydraulic pressure acts on the entire surface of the piston 61 when the hydraulic cylinder 60 is extended, a larger driving force can be obtained at the time of expansion than at the time of contraction. As a result, the outer diameter D3 of the excavation bucket body 70 is smaller than the inner diameter D1 of the shaft portion 101 of the pile hole 100 even if more earth and sand 110 generated by excavation of the expanded bottom portion 102 is taken into the inside of the excavation bucket body 70. Thus, the bottom-excavated bucket 10 located in the bottom-extended portion 102 can be reliably lifted to the ground side via the shaft portion 101 of the pile hole 100.

  In addition, the earth and sand 110 taken inside the excavation bucket body 70 is discharged to the ground side a plurality of times. Since the amount of earth and sand 110 taken up can be increased, the number of times earth and sand 110 is discharged to the ground side can be reduced. Further, since the plate-like second connecting link member 41 is swingably inserted into the space portion S penetrating in the vertical direction of the upper link member 44, the parallel moving link portion 40L can be made compact. Become. As a result, the bottom-excavation bucket 10 can be reduced in weight, and the amount of earth and sand taken after excavation by the bottom-excavation bucket 10 can be further increased.

  In this embodiment, in the bottomed excavation bucket 10, the vertical movement amount of the first lifting frame 20 is larger than the vertical expansion / contraction amount of the hydraulic cylinder 60. Even if set to be short, a large amount of radial movement of the excavation bucket body 70 relative to the pole 11 can be secured. The fact that the amount of expansion / contraction of the hydraulic cylinder 60 can be set short means that the vertical height H2 of the bottom-excavation bucket 10 can be reduced. Accordingly, the bottom excavation bucket 10 is a type of excavator that can reduce the height H2 in the vertical direction while maintaining the performance of excavating a pile hole having a large bottom expansion rate, and has a low lifting height. Also, the bottom-excavated bucket 10 can be used. Thereby, while being able to ease the constraint conditions regarding the excavation work of the pile hole 100, it is possible to increase the utility value of a model excavator having a low lifting height.

  After the pile hole 100 is constructed in a predetermined shape, the ready-mixed concrete is placed in the pile hole 100 shown in FIG. 19 (d), and the ready-mixed concrete reaches a predetermined height from the expanded bottom portion 102 of the pile hole 100. Supplied until When the ready-mixed concrete is finished, the opening of the pile hole 100 is backfilled with earth and sand 110. Further, since the bottom-excavation bucket 10 can be lowered in height, the earth drill machine 1 as an excavator can also position the bottom-excavation bucket 10 above the earth and sand 110 stacked at a height H1. Become.

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to the above-described embodiment, and even if there is a design change or the like without departing from the gist of the present invention, It is included in this invention. For example, in this embodiment, after the bottom-excavation bucket 10 is moved to the bottom of the pile hole 100 in a state where the diameter is smaller than the inner diameter of the shaft portion 101 of the pile hole 100, the diameter of the bottom-excavation bucket 10 is expanded. In this state, the bottom expansion excavation bucket 10 is moved upward to make the bottom expansion portion 102 into a predetermined shape, but after expanding the bottom expansion excavation bucket 10 above the bottom of the pile hole 100, the bottom expansion excavation bucket 10 is expanded. The bucket 10 may be moved downward to form the widened portion 102 having a predetermined shape.

  In this embodiment, one hydraulic cylinder 60 is used to drive a set of parallel movement link mechanisms 40. However, a single hydraulic cylinder 60 is used to drive a plurality of parallel movement link mechanisms 40. It is also possible to adopt a configuration.

  Furthermore, in this embodiment, the lower link member 43 and the connection bracket 42 are formed of separate members and are integrated by welding, but the lower link member 43 includes the shape of the connection bracket 42. It is good also as a structure which comprises from one member and forms the connection part A in the upper part.

1 Earth drill machine (excavator)
DESCRIPTION OF SYMBOLS 10 Bucket for widening excavation 11 Post 20 1st raising / lowering frame 30 2nd raising / lowering frame 40 Translation link mechanism 40L Translation link part 41 2nd connection link member 43 Lower link member 44 Upper link member 60 Hydraulic cylinder 70 Excavation Bucket body 80 Stabilizer 100 Pile hole 101 Shaft 102 Expanded bottom

Claims (5)

A post extending in the vertical direction and rotatable about the axis;
A first lifting frame attached to the outer periphery of the post and movable in the axial direction of the post while being engaged with the post around an axis;
A second lifting frame attached to the outer periphery of the first lifting frame and movable in the axial direction of the post in a state of being engaged with the first lifting frame around an axis;
A hydraulic cylinder connected to the first lifting frame and the second lifting frame and lifting and lowering the second lifting frame relative to the first lifting frame by vertically extending and contracting;
A translational link portion that is movable in the radial direction around the post is connected to the first lifting frame side, and a lower link member of the translational link portion is connected to the post via a first connection link member. And the lower link member is connected to the second elevating frame via a second connecting link member, and the upper and lower sides of the first elevating frame with respect to the vertical expansion and contraction amount of the hydraulic cylinder. A translational link mechanism that increases the amount of movement in the direction;
A bucket main body for excavation attached to an outer end portion of the translation link portion and capable of translation in a radial direction relative to the post by the translation link portion;
A bucket for excavating bottoms, characterized by comprising:   The connection position of the lower link member of the translation link portion is set to the second connection link member so that the load acting radially inward when the hydraulic cylinder is fully extended is maximized. The bucket for bottom expansion excavation of Claim 1 characterized by these.   A space portion penetrating in the vertical direction is formed in the upper link member constituting the parallel movement link portion, and the second connecting link member is swingably inserted in the space portion. The bucket for expanded bottom excavation according to claim 1 or 2.   The bottom excavation bucket according to any one of claims 1 to 3, wherein the excavation bucket main body includes a receiving plate extending in a horizontal direction for receiving excavated earth and sand.   2. A method for constructing a bottom portion of a pile hole using the bottom-excavation bucket according to claim 1, wherein the bottom diameter excavation bucket is in a state in which an outer diameter of the excavation bucket body is smaller than an inner diameter of a shaft portion of the pile hole. Is moved toward the bottom of the pile hole, and then the bottom-excavation bucket is moved upward or downward in a state where the excavation bucket body of the bottom-excavation bucket is moved radially outward. A bottom-enlarged portion construction method comprising forming a bottom-enlarged portion having an inner diameter larger than the inner diameter of the shaft portion.

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