JP5259689B2 - Extruder expansion head opening and closing device - Google Patents

Description

  The present invention relates to an opening / closing device for expanding / contracting an expansion excavating blade of an expansion head used for constructing a root-clamping bulb having an enlarged diameter at a tip portion of a pile such as a ready-made pile or a cast-in-place pile.

  In the construction of underground piles, for example, an earth auger is used as an excavator, and a normal excavating blade and an enlarged excavating blade are attached to the lower end portion of a excavating rod that is rotationally driven by a driving unit supported movably along the leader mast. First, excavate a vertical hole to the support layer with the expansion drilling blade contracted, then expand the expansion drilling blade and expand the drilling, and inject cement milk, mortar, etc. to build a rooted bulb Construction methods that increase the bearing capacity of piles are widely known.

  A conventional enlarged excavating blade is generally opened and closed using the resistance of earth and sand due to forward and reverse rotation of an excavating rod. For example, when the excavating rod rotates forward, the enlarged excavating blade is pressed and contracted by the earth and sand, and when the excavating rod rotates in the reverse direction, earth and sand enter the tip of the enlarged excavating blade, and the enlarged excavating blade rises outward. It has a structure that expands.

  However, in the case of a structure using the resistance of the earth and sand, a high reliability can be obtained with a simple structure in the soil with a lot of gravel, but in the soil with a small amount of gravel, the excavation rod as a whole has no unevenness. There is a problem that even if it is turned into a soil pillar state, the sand does not enter the tip portion of the enlarged excavating blade even if it is reversed, and it does not spread. In addition, there is a problem that an arbitrary diameter cannot be enlarged and the opening / closing cannot be visually confirmed.

  In order to solve such problems, various switchgears that can be opened and closed reliably using an operating mechanism have been developed. For example, switchgears as disclosed in Patent Documents 1 to 3 have been proposed.

  The invention of Patent Document 1 is an expansion head for excavation provided at the lower end of the excavation rod, and the distal end portion of the operation rod penetrating the excavation rod is applied to the upper surface of the base of the pair of left and right expansion excavation blades to be in a contracted state, The pair of left and right enlarged excavation blades are expanded by pulling up the operation rod with a center hole jack provided in the drive section above the excavation rod.

  The invention of Patent Document 2 is an excavation apparatus that expands and digs the inner part of a pile hole, and has an outer diameter that is substantially the same as the outer peripheral surface of the excavation rod at the lower end of the excavation rod, and the tip that idles when the excavation rod reverses A head is provided, and an enlarged excavating blade is provided on the tip head, and the enlarged excavating blade is erected and expanded by gear irregularities that engage when the excavating rod is reversed.

  The invention of Patent Document 3 is an expansion digging method and an expansion excavation head for creating a bulb at the underground lower end of a pile, and an expansion excavating blade expansion / contraction hydraulic pressure is provided inside the head rod of the expansion head connected to the lower end of the excavation rod. A cylinder is housed, and the expansion excavating blade can be expanded and contracted through a link by the expansion and contraction drive of the hydraulic cylinder. The hydraulic oil supply / discharge pipe of the hydraulic cylinder is guided vertically through the excavation rod, and is connected to the hydraulic circuit via a rotary joint in the drive unit. The amount of oil supplied to and discharged from the hydraulic cylinder is detected to detect the expanded diameter of the enlarged excavating blade, and the amount of oil is adjusted by a valve to increase or decrease the expanded diameter.

  In addition, in Patent Document 4, in the burying of ready-made piles, an expansion kneading unit whose diameter is enlarged and reduced by the upper arm and the lower arm is provided at the lower end of the excavation rod inserted into the hollow portion of the ready-made pile, For example, the lower end of the excavation rod An opening / closing mechanism is described in which the connecting plate is fitted to the upper surface of the opening / closing unit to expand the expanding / kneading unit, and the diameter of the expanding / kneading unit is reduced simply by pulling up the excavating rod.

  Patent Document 5 provides a pair of left and right excavating arms having an excavating blade at the tip on a fixed excavating blade of an excavating head mounted on the lower end of an excavating rod in an embedded pile. Maintains the open and closed states using a stopper that restricts excavation arm swing during forward rotation (shaft excavation) and a stopper that restricts excavation arm swing during reverse rotation (expanded excavation). An opening and closing mechanism is described.

  Moreover, in patent document 6, in the construction method which forms a mortar enlarged diameter part in the outer periphery in a patent document 6, and builds it in the ground, it has an axial direction space | interval in the outer peripheral surface of the hollow rod which has a drilling head in a lower end. A plurality of enlarged excavating blades are provided so as to be able to expand and contract, and a driving force transmission member such as a transmission rod is arranged so as to be movable up and down along the hollow rod from substantially the upper end portion of the hollow rod. Each expansion digging blade is connected continuously so that it can be expanded and contracted by the vertical movement of the driving force transmission member, and the expansion operation of each expansion digging blade is stepped up to the maximum expansion position at the upper end of the power transmission member. An opening / closing mechanism configured by connecting driving means such as an output hydraulic cylinder having a vertical driving force that can be operated is described.

Japanese Patent No. 3626647 Japanese Patent Laid-Open No. 2002-155561 JP 2002-322890 A JP 2003-064679 A JP 2003-213679 A Japanese Patent Laid-Open No. 2004-324381

  In the case of a structure that opens and closes an enlarged excavating blade using the resistance of earth and sand, as described above, there is a problem that it cannot be reliably expanded in soil quality with a small amount of gravel, and it is not possible to expand any diameter, and visual confirmation of opening and closing There are problems such as being unable to.

  In addition, in the case of an opening and closing device described in Patent Documents 1 to 6 that is reliably opened and closed using an operating mechanism, a hydraulic cylinder or jack having a large output is required as an opening and closing drive source, or an opening and closing mechanism is not provided. There are problems such as a complicated structure.

  The present invention has been made to solve the above-described problems, and in an opening / closing device for expanding / contracting an expansion excavation blade of an expansion head used for constructing a root consolidation bulb having an enlarged diameter at a tip portion of a pile. The enlargement excavation blade can be reliably opened and closed using the rotational driving force of the rotating shaft, and can be opened and closed without using a large output opening and closing drive source and by a relatively simple opening and closing mechanism. It is an object of the present invention to provide an enlargement head opening / closing device for an excavator that can be enlarged at an arbitrary diameter and that can be visually checked for opening / closing.

According to a first aspect of the present invention, an enlarged excavating blade of an enlarged head provided at the tip of a rotating shaft that is driven to rotate by a drive unit that is movable along a leader mast of an excavator is used to rotate the rotating shaft. An expansion head opening / closing device for an excavator that uses a driving force to expand and contract by a screw-type opening / closing operation jig, and the screw-type opening / closing operation jig is provided below the expansion excavating blade. includes a ring-shaped upper lid, a disc-shaped fixed base which is digging edge to the lower surface fixed, rotatable in the lower part of the outer periphery of the rotating shaft and vertically movably provided, a cylindrical internally threaded on the inner surface is provided and an internally threaded outer ring, the outer ring in the rotating shaft and integrally provided on the lower end of the rotating shaft located in a piston-like with a male thread male screw to be screwed into the internal thread of the outer ring is provided on an outer surface Has a shaft portion, the upper cover and the fixed base and the inner shaft part and the outer ring forms a housing in a state of suspended rotatably housed vertically movably, on the outer surface of the outer ring as the support ring of the actuating member of the expansion digging edge to be fitted into the ring-shaped groove formed on the outer peripheral surface of the outer ring is rotatably integrally next horizontally in a vertical direction with respect to the outer ring The rotation of the outer ring is stopped by the ground with respect to the rotating shaft that rotates forward and reverse, and the outer ring is raised and lowered with respect to the inner shaft portion by screw-rotating the inner shaft portion with respect to the outer ring, An expansion head opening / closing device for an excavator, wherein the expansion excavation blade is configured to be expanded / contracted via a support ring and an operating member by raising / lowering the outer ring. It is.

  For example, as shown in FIG. 5, this is a case of a lower operation method in which an opening / closing operation jig for an enlarged excavating blade is provided on an enlarged head below the rotary shaft. First, drill the vertical hole to the support layer with the expanded excavation blade closed, and when it reaches the support layer, press the excavation blade at the lower end of the rotating shaft against the ground to fix the outer ring and press the excavation blade at the lower end By rotating the rotating shaft in the reverse direction, the inner shaft portion is screwed downward, and the outer ring rises relative to the inner shaft portion, so that the enlarged excavating blade is expanded. By adjusting the screwing amount of the inner shaft portion, the enlarged diameter of the enlarged excavating blade can be arbitrarily changed. If the rotating shaft is rotated in the direction opposite to that at the time of expansion, the outer ring descends relatively and the expansion excavation blade closes.

  In this case, by using the rotational driving force of the rotating shaft, the enlarged excavation blade can be reliably opened and closed by a screw method using the outer ring and the inner shaft portion at the lower part of the rotating shaft, without using a large output opening / closing driving source. Moreover, it can be opened and closed by a relatively simple opening and closing mechanism using a screw system, and the enlarged excavating blade can be enlarged to an arbitrary diameter. Furthermore, the open / closed state of the enlarged excavating blade can be easily confirmed visually by moving the rotary shaft up and down.

  According to a second aspect of the present invention, an enlargement excavation blade of an enlargement head provided at the tip of a rotation shaft that is rotationally driven by a drive unit that is movable along a leader mast of an excavator is used to rotate the rotation shaft. An expansion head opening / closing device of an excavator that uses a driving force to expand and contract by a screw-type opening / closing operation jig, and is provided on the outer surface of an outer screw member of the screw-type opening / closing operation jig provided at the upper part of a rotating shaft. A contact member that contacts the rotation stop member to stop the rotation of the outer screw member is provided, and an overload prevention means is provided between the contact member and the outer screw member. A mounting shaft to which the abutting member is mounted, a mounting plate that is mounted on the outer surface of the outer screw member and rotatably supports the mounting shaft, and is mounted on the mounting shaft so as to be integrally rotatable, and is in surface contact with the surface of the mounting plate A friction plate that is an enlarged head switchgear excavator, characterized in that it is a spring member for pressing the friction plate on the surface of the mounting plate.

  For example, as shown in FIG. 2, the protrusion member (swivel bar) is provided with spring-type overload prevention means, but the opening / closing operation by the outer ring (outer screw member) and the inner ring in FIG. For example, a female thread ring (outer thread member) is provided on the male thread portion of the rotating shaft, not limited to rotation stopping means using a protruding member (swivel bar) as a contact member and a reaction force member (reaction arm) as a rotation stop member. Mounting, opening / closing operation jig that raises and lowers the female screw ring by stopping the rotation of the female screw ring, rotation stop to contact the vertical reaction force plate (rotation stop member) by providing a roller (contact member) on the outer surface of the female screw ring It can also be applied to means.

  Next, for reference, related inventions invented simultaneously with the present invention will be shown. This is an enlargement head opening and closing device that opens and closes an enlargement excavation blade of an enlargement head provided at the tip of a rotary shaft (excavation rod) that is driven to rotate by a drive unit movable along the leader mast of the excavator An opening / closing operation jig provided on the upper part of the rotating shaft, and an operating rod which can be moved up and down along the rotating shaft and can be rotated together with the rotating shaft. The operating jig is rotatably supported on the outer periphery of the rotating shaft, and is disposed so as to be movable up and down along the rotating shaft between the outer ring and the rotating shaft. It has an inner ring provided with a male thread that engages with the female thread of the outer ring, and an operating rod is attached to this inner ring. By stopping the rotation of the ring, the inner ring is screwed up and down along the rotating shaft by the operating rod that rotates together with the rotating shaft, and the operating rod is moved up and down by raising and lowering the inner ring to expand and contract the enlarged excavating blade An enlarged head opening / closing device for an excavator, which is configured to open and close.

  This is the case of the upper operation method in which an opening / closing operation jig for the enlarged excavating blade is provided on the upper portion of the rotating shaft, as shown in FIGS. First, a vertical hole is excavated to the support layer with the expanded excavation blade being closed, and when the support layer is reached, the rotation of the outer ring is stopped by the rotation stopping means. The screw rotates along the inner surface of the outer ring with a female thread, and moves upward along the rotary shaft. As the inner ring rises, the operating rod rises, and the enlarged excavation blade expands. The enlarged diameter of the enlarged excavating blade can be arbitrarily changed by adjusting the rotation speed or time for stopping the rotation of the outer ring. If the rotation shaft is reversely rotated in the state where the rotation of the outer ring is stopped by the rotation stopping means, the inner ring is lowered and the enlarged excavation blade is closed.

  Using the rotational driving force of the rotating shaft, the enlarged excavation blade can be reliably opened and closed by the screw method and operation rod by the outer ring and inner ring at the upper part of the rotating shaft, without using a large output opening and closing drive source, In addition, the opening and closing can be performed by a relatively simple opening and closing mechanism using the inner and outer rings and the operating rod, and the enlarged excavating blade can be enlarged to an arbitrary diameter. Furthermore, the open / closed state of the enlarged excavating blade can be easily confirmed visually by moving the operating rod up and down.

  Further, in the enlarged head opening / closing device according to the related invention, the rotation stop means of the outer ring is protruded from the outer surface of the outer ring so as to protrude sideways, and can be extended and contracted from the driving portion toward the protrusion member. And a reaction force member that stops the turning of the protruding member by locking the protruding member at the distal end portion when extended.

  For example, as shown in FIG. 4, a reaction member (reaction arm) such as a piston rod of a fluid pressure cylinder provided in the drive unit is extended, and a projecting member (swivel bar) whose tip is located on the outer ring outer periphery. ) To stop the rotation of the outer ring. In addition to such rotation stopping means, a drum brake system in which a brake shoe is pressed against the outer periphery of the outer ring with a hydraulic cylinder or the like and rotation is stopped by frictional resistance, or a cam clutch system can be used.

  Further, in the enlarged head opening / closing device according to the related invention, an overload preventing means is provided between the outer ring and the protruding member, and the overload preventing means is provided on the mounting shaft to which the protruding member is attached and the outer surface of the outer ring. A mounting plate that is mounted and rotatably supports the mounting shaft, a friction plate that is mounted on the mounting shaft so as to rotate together and is in surface contact with the surface of the mounting plate, and presses the friction plate against the surface of the mounting plate It can also be composed of a spring material.

  For example, as shown in FIG. 2, a spring-type overload prevention means is provided on the protruding member (swivel bar), and the friction plate is attached by the pressing force of a spring material (a disc spring, a coil spring, etc.). Usually, the mounting shaft is fixed to the mounting plate by the surface friction force between the friction plate and the mounting plate, and a large force acts on the protruding member when stopping the rotation of the outer ring when opening and closing the enlarged excavating blade. However, the projecting member can be reliably opened and closed without rotating. When an excessive force is applied to the protruding member due to screw seizure or the like, the friction plate slides with respect to the mounting plate, the mounting shaft / projecting member rotates, and overload is prevented.

Since the present invention is configured as described above, the following effects can be obtained.
(1) Since the rotational driving force of the rotating shaft is used and the screw method using the outer ring and the inner shaft portion below the rotating shaft is used, the enlarged excavating blade can be opened and closed reliably.
(2) Since the rotational driving force of the rotating shaft is used, an open / close drive source with a large output is not required, and the open / close mechanism can be made relatively simple by using a screw system. Cost can be reduced.
(3) The enlarged excavating blade can be enlarged to an arbitrary diameter by a relatively simple opening and closing mechanism using a screw method.
(4) The open / close state of the enlarged excavating blade can be easily confirmed visually by moving the rotary shaft up and down.
(5) By providing the spring-type overload prevention means, it is possible to prevent overload with a relatively simple configuration, and to open and close the enlarged excavating blade safely and reliably.

1 is an overall view showing an example of an excavator equipped with an expansion head according to the present invention. It is an embodiment of the enlarged head opening and closing device of the related invention of the present invention, showing an example of the upper operation method provided on the upper portion of the rotating shaft (a) is a cross-sectional view, (b), (c) is a plan view, d) is a sectional view of the torque guard. It is a fragmentary sectional view showing an example of an expansion head. FIG. 1A is a plan view and FIG. 1B is a side view showing the entire enlarged head opening / closing device of FIG. It is an embodiment of the expansion head opening and closing device of the present invention, and is a front view showing an example of a lower operation method provided on the expansion head below the rotary shaft.

  Hereinafter, the present invention will be described based on the illustrated embodiments. This embodiment is an example applied to a tip rooting method such as a ready-made pile or a cast-in-place pile. FIG. 1 is an overall view showing an example of an excavator equipped with an expansion head according to the present invention. FIG. 2 is a cross-sectional view and a plan view showing an example of the upper operation method provided on the upper portion of the rotating shaft, which is an embodiment of the enlarged head opening / closing device according to the related invention of the present invention. FIG. 3 is a partial cross-sectional view showing an example of an enlarged head. FIG. 4 is a plan view and a side view showing the entire enlarged head opening / closing device of FIG. FIG. 5 is a front view showing an example of a lower operation method provided in the enlarged head below the rotary shaft, which is an embodiment of the enlarged head opening / closing device of the present invention.

  In FIG. 1, the excavator is an earth auger, a leader mast 2 is vertically supported by a base machine 1 via a stay, and a drive unit (motor / reduction gear) 3 slides up and down on a guide rail in front of the leader mast 2. A wire rope from a winch on the base machine 1 is connected to the drive unit 3, and the drive unit 3 moves up and down along the leader mast 2 by winding and unwinding the winch. The upper end of the rotary shaft (excavation rod) 4 is connected to the output shaft of the drive unit 3 so that the rotary shaft 4 is driven to rotate. On the lower front surface of the leader mast 2, a steady rest 5 for the rotating shaft 4 is provided.

  The rotating shaft 4 is provided with a spiral blade 6 on the outer periphery of an intermediate portion, and an enlarged head 7 is provided at a tip portion. The rotary shaft 4 of the magnifying head 7 is provided with a normal digging blade 8 at the lower end, and a pair of left and right magnifying digging blades 9 and 9 that expand and contract on and off. The rotating shaft 4 is configured by connecting a shaft having a unit length by a joint 10.

  In an excavator equipped with such an enlarged head, in the upper operation method of the present invention, as shown in FIG. 1, an opening / closing operation jig 20 is provided on the outer periphery of the upper portion of the rotating shaft 4 at the lower portion of the drive unit 3 to rotate the excavator. Operation rods 21 are arranged on the left and right sides of the shaft 4 along the rotation shaft 4, and the opening / closing operation jig 20 and the enlarged excavation blade 9 are connected via the pair of left and right operation rods 21, 21 with the rotation shaft 4 interposed therebetween. To do. The pair of operating rods 21, 21 penetrates the spiral blade 6 and is attached to the rotating shaft 4 so as to be movable up and down. While rotating together with the rotating shaft 4, the pair of operating rods 21 and 21 are moved up and down by operating the opening / closing operation jig 20. The excavating blades 9 and 9 are opened and closed.

  As shown in FIG. 2, the opening / closing operation jig 20 is configured to move the operation rod 21 up and down by a screw method using the rotational driving force of the rotary shaft 4, and mainly includes a ring-shaped upper lid 30 and a ring-shaped upper lid 30. The rotation stop means 34 stops the rotation of the outer ring 32 that rotates together with the rotary shaft 4, and includes a fixed base 31, a cylindrical female threaded outer ring 32, and a piston-shaped male threaded inner ring 33. The inner ring 33 that rotates forward and backward together with the rotating shaft 4 and the operating rod 21 is moved up and down along the rotating shaft 4 while rotating along the inner surface internal thread of the outer ring 32, and the operating rod 21 is moved up and down by moving up and down the inner ring 33. The enlarged excavating blade 9 is expanded and contracted by moving the operating rod 21 up and down.

  The fixed base 31 is fixed to the outer peripheral surface of the rotating shaft 4 by welding or the like. An outer ring 32 is placed on the outer peripheral upper surface of the fixed base 31, and an upper lid 30 is placed on the outer ring 32 to cover it. 30 and the fixing base 31 are fixed with a plurality of bolts and nuts 35 at intervals in the circumferential direction (see FIG. 2B). The upper lid 30, the fixed base 31, and the outer ring 32 form a housing in which the inner ring 33 is housed so as to be movable up and down. A bearing metal or the like is disposed between the outer ring 32 and the upper lid 30 / fixed base 31. The outer ring 32 is rotatably supported, and can stop the rotation of the rotating shaft 4 and the like. it can. The operation rod 21 passes through the upper lid 30 and the fixed base 31 and is supported so as to be movable up and down.

  The outer ring 32 has a vertical length such that a desired expansion / contraction stroke of the expansion excavation blade 9 can be obtained, and a female female 32a is cut over the entire inner surface thereof. The inner ring 33 has a male screw 33a that is screwed into the female screw 32a of the outer ring 32, and the rotary shaft 4 is inserted in the center hole with a gap therebetween. 4 moves up and down. The length of the inner ring 33 in the vertical direction is short, and an up / down stroke corresponding to the expansion / contraction stroke of the expansion excavating blade 9 is obtained. The inner ring 33 and the operation rod 21 penetrating the inner ring 33 are fixed by welding or the like.

  The opening / closing operation jig 20 is provided on the divided rotary shaft 4 having a unit length. The upper end of the rotary shaft 4 is connected to the output shaft 3a (FIG. 1) of the drive unit 3 by a joint, and the lower end is connected to the lower portion. The rotating shaft 4 is connected by a joint. A supply hole 40 for cement milk or the like is provided at the center of the rotating shaft 4. The operating rod 21 is also divided in the same manner as the rotating shaft 4 and is connected by a coupler 41. Further, a rod guide 42 through which the operating rod 21 is inserted is attached to the rotating shaft 4 by welding, and the operating rod 21 can be rotated integrally with the rotating shaft 4 and can be moved up and down with respect to the rotating shaft 4. Is done.

  The structure of the magnifying head 7 is, for example, as shown in FIG. 3, and the tip shaft 50 is inserted into the rotating shaft 4 of the magnifying head 7 so as to be integrally rotatable and vertically slidable by a non-rotating sliding key or the like. The enlarged excavating blade 9 is attached to the lower side surface of the rotating shaft 4 so as to be rotatable in the vertical direction by a shaft 51. A fixed ring 52 is fixed to the outer periphery of the tip shaft 50 at the lower portion of the enlarged excavating blade 9, and the fixed ring 52 and an intermediate portion of the enlarged excavating blade 9 are connected via a link plate 53. The operation rod 21 is connected to the upper part of the fixing ring 52. When the operation rod 21 is lowered, the tip shaft 50 slides and protrudes downward, and the enlarged excavation blade 9 contracts downward. When the operating rod 21 is raised, the tip shaft 50 is slid upward and retracted, and the enlarged excavating blade 9 is expanded upward. The structure of the enlarged excavating blade 9 is not limited to this, and the arrangement of the enlarged excavating blade 9 and the link 53 can be reversed and the structure can be closed upward.

  For example, as shown in FIGS. 2 and 4, the rotation stopping means 34 for stopping the rotation of the outer ring 32 includes a swiveling bar 60 as a protruding member provided so as to protrude sideways on the outer surface of the outer ring 32, and a drive unit. The reaction force arm 61 can be configured as a reaction force member which is provided so as to be extendable from 3 toward the swivel bar 60 and whose front end portion locks the swivel bar 60 and stops turning of the swivel bar 60 when extended.

  A mounting plate 62 is projected on the outer surface of the outer ring 32 with a gap in the vertical direction, and the base of the swivel bar 60 is inserted into the upper and lower mounting plates 62 and mounted via a vertical mounting shaft 63. The reaction arm 61 can be constituted by a piston rod or the like of the fluid pressure cylinder 64, and the cylinder body is attached to the side surface of the drive unit 3. It is preferable that the swivel bar 60 and the reaction force arm 61 are arranged in a pair on the left and right sides to disperse the acting load.

  When the rotary shaft 4 is driven to rotate by the drive unit 3 to dig up and reach a diameter-expanded position, the reaction arm 61 is extended so that the tip end is brought into contact with the side surface of the swivel bar 60 and the rotation of the outer ring 32 is stopped. The enlarged excavating blade 9 is expanded by the rotation of the shaft 4. Also in the case of closing, similarly, the rotation of the outer ring 32 is stopped, and the enlarged excavation blade 9 is contracted by the rotation of the rotating shaft 4 in the reverse direction.

  Here, in order to stop the rotation of the outer ring 32 and operate the opening / closing mechanism with the output torque of the auger, the torque guard 65 (see FIG. 2) is attached to the mounting plate 62 so that the auger device of the drive unit 3 is not overloaded. Is preferably provided. The torque guard 65 can be composed of a friction plate 66 and a disc spring 67 as shown in FIG. The attachment shaft 63 is rotatably attached to the upper and lower four attachment plates 62, and the friction plates 66 are attached to the upper and lower attachment shafts 63 through a key or the like so as to be integrally rotatable. The friction plates 66 are arranged in pairs so as to be in surface contact with the inner surfaces of the upper and lower mounting plates 62 and spaced apart from each other, and a disc spring 67 is disposed therebetween, so that the friction plates 66 are pressed against the inner surface of the mounting plate 62. So that

  Usually, the mounting shaft 63 is fixed to the mounting plate 62 by the four surface frictional forces of the friction plate 66 and the mounting plate 62, and a large force is applied to the swivel bar 60 when stopping the rotation of the outer ring 32 when the enlarged excavating blade is opened and closed. Even if it acts, the swivel bar 60 can be reliably opened and closed without rotating. Possible causes of overload include seizure of the outer ring 32 and the inner ring 33, as well as breakage of the threaded portion and dust. If an excessive force acts on the swivel bar 60, the friction plate 66 is applied to the mounting plate 62. On the other hand, the mounting shaft 63 and the swivel bar 60 are rotated to prevent overload. As a double safety measure, a shear pin may be arranged between the swivel bar 60 and the mounting shaft 63.

  In addition, when an overload state occurs, the current value increases, the breaker operates (shuts down), stops the rotation of the auger, and when the breaker is inserted after a while, the auger can be restarted.

  Further, the rotation stopping means 34 for stopping the rotation of the outer ring 32 is not limited to the above-described method using the swiveling bar and the reaction force arm. For example, a brake shoe is disposed on the outer periphery of the outer ring 32 and this brake shoe is used as a hydraulic cylinder. It is also possible to use a drum brake system that presses with a frictional force and stops the rotation with the frictional resistance. Furthermore, a cam clutch system etc. can also be used.

  Using the enlarged head opening and closing device configured as described above, for example, the inside boring method for sinking a pre-made pile while drilling or the pre-boring method for placing a pre-made pile after drilling is performed in the following procedure. Implement the tip-hardening method.

  (1) First, a vertical hole is excavated to the support layer in a state where the enlarged excavating blade 9 is contracted. As shown in FIG. 2 (a), the inner ring 33 is at the lowermost position, the operating rod 21 fixed thereto is lowered, and the enlarged excavating blade 9 is closed as shown on the right side of FIG. Yes. Further, the outer ring 32 and the inner ring 33 are integrated by screws, and rotate together with the rotating shaft 4 and the operation rod 21.

  (2) When reaching the support layer, the expanded excavating blade 9 is expanded and expanded, and cement milk, mortar, etc. are injected to build a root-capped bulb. When the rotation of the outer ring 32 is stopped by the rotation stopping means 34, the inner ring 33 rotating together with the rotating shaft 4 moves upward along the rotating shaft 4 while rotating along the inner surface of the outer ring 32. As the inner ring 33 rises, the operating rod 21 rises, and the enlarged excavation blade 9 expands as shown on the left side of FIG. If the rotation stop of the outer ring 32 by the rotation stop means 34 is released, the inner ring 33 does not rise integrally with the outer ring 32 with a screw, and the expanded state of the expanded excavating blade 9 is maintained. By adjusting the rotation speed or time for stopping the rotation of the outer ring 32, the enlarged diameter of the enlarged excavating blade 9 can be arbitrarily changed.

  (3) When the tip rooting work is finished and the rotary shaft 4 is pulled up, the rotation of the outer ring 32 is stopped by the rotation stop means 34, and the inner ring can be reversed by rotating the rotary shaft 4 in the reverse direction. 33 descends and the enlarged excavation blade 9 closes. The expansion / contraction state of the expansion excavation blade 9 can be easily confirmed by the protruding amount of the operation rod 21 protruding upward from the opening / closing operation jig 20 (see FIG. 2A).

  Next, FIG. 5 is an example in which the opening / closing operation jig 20 is provided in the enlargement head 7. In this case as well, the enlarged excavation blade 9 is opened and closed by a screw method using the rotational driving force of the rotating shaft 4, but the operating rod is directly attached to the lower portion of the rotating shaft 4 and uses the ground for fixing. 21. The rotation stopping means 34 can be omitted.

  The opening / closing operation jig 20 is mainly composed of a ring-shaped upper lid 70, a disk-shaped fixed base 71, a cylindrical female-threaded outer ring 72, and a piston-shaped male-threaded inner shaft portion 73. An inner shaft portion that rotates forward and backward together with the rotating shaft 4 by pressing the excavating blade 8 at the lower end of the shaft 4 against the ground to fix the outer ring 72 and rotating the rotating shaft 4 forward and backward while pressing the excavating blade 8. 73 is moved up and down along the internal thread of the inner surface of the outer ring 72, and the outer ring 72 is moved up and down relative to the inner shaft portion 73 to open and close the enlarged excavating blade 9.

  The excavating blade 8 is fixed to the lower surface of the fixed base 71, an outer ring 72 is placed on the outer periphery of the upper surface of the fixed base 71, and an upper lid 70 is placed on the outer ring 72 to cover it. The upper lid 70 is attached to the lower end portion of the rotary shaft 4 so as to be rotatable with respect to the rotary shaft 4 by the rotary shaft 4 being inserted into the center mounting hole and being locked to the upper surface of the step portion of the inner shaft portion 73. It is done. The upper lid 70, the fixed base 71, and the outer ring 72 form a housing in which the inner shaft portion 73 is housed so as to be movable up and down. Since the housing / excavation blade 8 is provided in a state of being rotatably suspended, the rotation can be stopped with respect to the rotating rotary shaft 4 and the like.

  The outer ring 72 has a vertical length such that a desired expansion / contraction stroke of the expansion excavation blade 9 can be obtained, and a female female 72a is cut over the entire inner surface thereof. The inner shaft portion 73 is integrally formed by, for example, slightly increasing the outer diameter of the lower end portion of the rotary shaft 4, and a male screw 73 a that engages with the female screw 72 a of the outer ring 72 is cut to the outer surface. It moves up and down while rotating with respect to the fixed outer ring 72. The length of the inner shaft portion 73 in the vertical direction is short, and an up / down stroke corresponding to the expansion / contraction stroke of the enlarged excavating blade 9 is obtained.

  As in FIG. 3, the enlarged excavating blade 9 is attached to a fixed ring 80 fixed to the lower portion of the rotating shaft 4 so as to be rotatable in the vertical direction via a shaft 81, and is opened and closed by a link plate 82 that moves up and down. In the case of FIG. 5, since the outer ring 72 stops rotating with respect to the rotating shaft 4 and the enlarged excavating blade 9, the support ring 83 on which the lower end of the link plate 82 is pivotally attached is provided on the outer peripheral surface of the outer ring 72. The support ring 83 is integrated in the vertical direction with respect to the outer ring 72 and is freely rotatable in the horizontal direction. As will be described later, when the rotating shaft 4 is rotated, the outer ring 72 is moved up and down relatively with respect to the rotating shaft 4, and the enlarged excavating blade 9 is opened and closed.

  The outer ring 72 can be fixed by pressing the lower excavation blade 8 against the ground. If the rotary shaft 4 is rotated in the direction opposite to that at the time of drilling while pressing the excavating blade 8 against the ground from the closed state of FIG. 5A, the inner shaft along the inner surface internal thread 72a of the fixed outer ring 72 The male screw 73a of the portion 73 is screwed downward and the outer ring 72 is relatively raised, so that the enlarged excavating blade 9 is expanded as shown in FIG. 5 (b). If the rotary shaft 4 is rotated forward when closing, the inner shaft portion 73 is screw-rotated upward and the outer ring 72 is relatively lowered, so that the enlarged excavation blade 9 is contracted.

  Here, in this embodiment, it is conceivable that the screw is rotated by the rotation of the rotary shaft 4 during drilling / enlarged excavation, and the enlarged excavation blade 9 is opened / closed. For example, normal rotation during drilling of the rotary shaft 4 is possible. Is rotated to the right, if the female thread 72a and male thread 73a of the outer ring 72 and the inner shaft portion 73 are left-handed, the screw does not rotate during the expanded excavation by rotating the rotating shaft 4 to the right. The inner shaft portion 73 is not lowered by this rotation, and an expanded state with an arbitrary diameter is maintained. During contracted excavation, the inner shaft portion 73 tends to rise by the right rotation of the rotating shaft, but the contracted state is maintained by the upper limit of the lifting stroke.

  Also in this case, the tip rooting method is carried out by the following procedure using the inside boring method or the pre-boring method.

  (1) First, a vertical hole is excavated to the support layer in a state where the enlarged excavating blade 9 is contracted. As shown in FIG. 5A, the inner shaft portion 73 is at the uppermost position, the outer ring 72 is lowered, and the enlarged excavation blade 9 is closed. The outer ring 72 and the inner shaft portion 73 are integrated with screws and rotate together with the rotating shaft 4.

  (2) When reaching the support layer, the expanded excavating blade 9 is expanded and expanded, and cement milk, mortar, etc. are injected to build a root-capped bulb. The outer ring 72 is fixed by pressing the excavating blade 8 at the lower end of the rotating shaft 4 against the ground, and the inner shaft portion 73 is screwed downward by rotating the rotating shaft 4 backward while pressing the excavating blade 8. As the outer ring 72 rises relative to the shaft portion 73, the enlarged excavating blade 9 is expanded as shown in FIG. 5 (b). By adjusting the screwing amount of the inner shaft portion 73, the enlarged diameter of the enlarged excavating blade 9 can be arbitrarily changed.

  (3) In the case where the tip rooting work is completed and the rotary shaft 4 is pulled up, if the rotary shaft 4 is rotated in the opposite direction, that is, the direction during excavation, the outer ring 72 is relatively lowered. The enlarged excavating blade 9 is closed. Also in this case, the expansion / contraction state of the expansion excavation blade 9 can be easily confirmed by the amount of vertical movement of the upper portion of the rotary shaft 4 or the like.

  The present invention is not limited to ready-made piles, and can also be applied to tip rooting methods such as cast-in-place piles.

DESCRIPTION OF SYMBOLS 1 ... Base machine 2 ... Leader mast 3 ... Drive part (motor, reduction gear)
4 ... Rotating shaft (drilling rod)
DESCRIPTION OF SYMBOLS 5 ... Anti-rest 6 ... Spiral blade 7 ... Expansion head 8 ... Excavation blade 9 ... Expansion excavation blade 10 ... Joint 20 ... Opening / closing operation jig 21 ... Operation rod 30 ... Upper lid 31 ... Fixed base 32 ... Outer ring with internal thread 33 ... Male screw Inner ring 34 ... Rotation stop means 35 ... Bolt / nut 40 ... Supply hole 41 ... Coupler 42 ... Rod guide 50 ... Tip shaft 51 ... Shaft 52 ... Fixed ring 53 ... Link plate 60 ... Swivel bar 61 ... Reaction force arm 62 ... Mounting plate 63 ... Mounting shaft 64 ... Fluid pressure cylinder 65 ... Torque guard 66 ... Friction plate 67 ... Belleville spring 70 ... Upper lid 71 ... Fixed base 72 ... Outer ring with female thread 73 ... Inner shaft part with male thread 80 ... Fixed ring 81 ... Shaft 82 ... Link plate 83 ... Support ring

Claims (2)

Screw-type opening / closing operation using the rotary driving force of the rotary shaft for the enlarged drilling blade of the enlarged head provided at the tip of the rotary shaft that is driven to rotate by a drive unit movable along the leader mast of the excavator This is an expansion head opening / closing device for an excavator that expands and contracts with a jig. The screw-type opening / closing operation jig is provided below the expansion excavating blade, and this opening / closing operation jig is excavated on a ring-shaped upper lid and a lower surface. A disk-shaped fixed base with a fixed blade, a cylindrical outer ring with a female thread provided on the inner periphery of the outer ring with a female thread on the inner surface, and an outer ring provided inside the outer ring. provided at the lower end of the rotating shaft located in a rotating shaft and integrally has a piston-like externally threaded within the shaft portion of the male screw to be screwed into the internal thread of the outer ring is provided on an outer surface, said upper lid The fixing base and the inner shaft part and the outer ring forms a housing in a state of suspended rotatably housed vertically movably, on the outer surface of the outer ring formed on the outer peripheral surface of the outer ring A rotation ring that rotates forward and backward is provided so that the support ring of the working member of the enlarged excavation blade fitted in the ring-shaped concave groove is integrated with the outer ring in the vertical direction and is rotatable in the horizontal direction. The rotation of the outer ring with respect to the shaft is stopped by the ground, and the inner shaft portion is screw-rotated with respect to the outer ring to raise and lower the outer ring with respect to the inner shaft portion. An expansion head opening / closing device for an excavator, wherein the expansion excavation blade is configured to be expanded / contracted through an operating member.   Screw-type opening / closing operation using the rotary driving force of the rotary shaft for the enlarged drilling blade of the enlarged head provided at the tip of the rotary shaft that is driven to rotate by a drive unit movable along the leader mast of the excavator An expansion head opening / closing device of an excavator that is expanded / contracted by a jig, and is provided on an upper portion of a rotary shaft, and is in contact with a rotation stop member on an outer surface of an outer screw member of the screw type opening / closing operation jig. A contact member that stops rotation of the contact member, and an overload prevention means is provided between the contact member and the outer screw member. The overload prevention means includes an attachment shaft to which the contact member is attached, and an outer side. A mounting plate that is mounted on the outer surface of the screw member and rotatably supports the mounting shaft, a friction plate that is mounted on the mounting shaft so as to be integrally rotatable and is in surface contact with the surface of the mounting plate, and the friction plate is mounted It enlarged head switchgear of the excavator, characterized in that a spring member which presses on the surface.

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