JP2011190638A - Hammer grab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hammer grab capable of decreasing frictional resistance of a swivel mechanism. <P>SOLUTION: A hanging shaft body 2 comprising upper-side large-diameter shaft portion 3 and a lower-side small-diameter shaft portion 4 is provided: a cylindrical base frame 5 rotatably coupled via a thrust bearing 6 is suspended on the large-diameter shaft portion 3 of the hanging shaft body 2; an external cylinder member 8 constituting a swivel mechanism 7 is rotatably fitted to the small-diameter shaft portion 4 using the small-diameter shaft portion 4 as an internal cylinder member; a cylindrical body frame 9 is suspended and coupled to the lower portion of the cylindrical base frame 5; shells 11 and 11 are pivotally attached to the lower end side of the cylindrical body frame 9; a cylinder 12 for driving the opening/closing of the shell is installed in the cylindrical body frame 9; an ascending/descending frame 13 is provided below the cylinder 12; the cylinder 12 is interlocked with and coupled to the ascending/descending frame 13; the ascending/descending frame 13 and the shells 11 and 11 are interlocked and coupled together by a link mechanism 14; and the shells 11 and 11 are opened/closed by lifting and lowering the ascending/descending frame 13 by a telescopic operation of the cylinder 12. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hammer grab used for obstacle removal work such as excavation and excavation work inside a casing in the cast-in-place pile method or other foundation work, and picking up an existing pile that has been cut or crushed.

  Conventionally, in the cast-in-place pile method and other foundation works, means for excavating a steel pipe as a casing driven into the ground using a hammer grab has been used. For example, as shown in the working state diagram of FIG. 7, a casing (steel pipe) C is driven into the ground G using an all-round rotation drive device A, and a hammer grab is suspended by a suspension wire E hanging from the tip of a jib D of a crane B. H is suspended and lowered into the casing C, and the shell F is opened and closed to perform underground excavation and earth removal work.

  As a conventional hammer grab, for example, there is one described in Patent Document 1 below. This hammer grab fixes a shell mounting frame to the lower end portion of the cylindrical base frame, pivots the shell to the shell mounting frame, and concentrically arranges a cylinder for opening and closing the shell in the cylindrical base frame, An elevating frame is provided at the lower part in the cylindrical base frame so as to be movable up and down, and this elevating frame is concentrically connected to the lower end side of the cylinder, and the upper end side of the cylinder is externally fitted to the inner shaft body and the shaft. The lower end portion of the inner shaft body of the supply / discharge oil swivel mechanism composed of the outer cylinder body is concentrically connected, and the upper end portion of the cylindrical base frame is fixed to the lower end portion of the inner shaft body to The cylinder is provided with a hanging connection portion that is suspended by a crane, and the lifting frame and the shell are linked and linked by a link mechanism so that the shell is opened and closed by the lifting and lowering of the lifting frame by the expansion and contraction operation of the cylinder.

  According to this hammer grab, the cylindrical base frame, the shell mounting frame, the shell, the shell opening / closing drive hydraulic cylinder, the lifting frame, and the inner shaft body of the swivel mechanism are integrally connected to each other. The swivel mechanism outer cylinder is rotatable relative to the swivel mechanism, and the suspension connection portion provided integrally with the swivel mechanism outer cylinder is held in a fixed state, so that the series of members is free to rotate. Therefore, in foundation work such as cast-in-place pile method, when performing excavation and earthing work inside the casing in parallel to the rotary excavation of the casing, Even if it comes into contact with the rotating casing, a series of members consisting of a cylindrical base frame, a shell mounting frame, a hydraulic cylinder, a lifting frame, and an inner shaft body of a swivel mechanism rotate together, so that a suspended connection portion Since is held in a non-rotating state, and the like for hanging wires and hydraulic pipes tube twist, there is no risk of cutting or damage.

JP 2009-138394 A

  By the way, in the conventional hammer grab described above, since the inner shaft body of the swivel mechanism comprising the inner shaft body and the outer cylinder body is configured to bear most of the load of the hammer grab, the inner shaft of the swivel mechanism The body needs to be thick and strong enough to withstand the load. Between the inner shaft body and the outer cylinder body of the swivel mechanism, there are a plurality of annular communication passages through which pressure oil passes, and a seal member such as an O-ring is interposed, so the diameter of the inner shaft body As the thickness increases, the frictional resistance between the inner shaft and the outer cylinder increases, and the inner shaft and the outer cylinder rotate together. There was a risk of twisting.

  An object of this invention is to provide the hammer grab which can make the frictional resistance between the inner shaft body and outer cylinder body in a swivel mechanism small as much as possible in view of said situation.

  Means for solving the above problems will be described with reference numerals in the embodiments described later. The hammer grab according to the first aspect of the present invention includes an upper large diameter shaft portion 3 and a lower small diameter shaft. A suspension shaft body 2 comprising a portion 4 is provided, and a cylindrical base frame 5 that is rotatably connected via a thrust bearing 6 is suspended from the large-diameter shaft portion 3 of the suspension shaft body 2, and the diameter An outer cylinder member 8 constituting a cylinder supply / discharge oil swivel mechanism 7 is rotatably fitted and held on the small shaft portion 4 with the small shaft portion 4 serving as an inner cylinder member, and is disposed below the cylindrical base frame 5. The cylindrical main body frame 9 is suspended and connected, and a plurality of shells 11 and 11 are pivotally attached to the lower end side of the cylindrical main body frame 9, and a shell opening / closing drive cylinder 12 is installed in the cylindrical main body frame 9. An elevating frame 13 is provided therebelow, and the cylinder 12 is linked to the elevating frame 13 and connected to the elevating frame 13 and the shell. And 11, 11 interlockingly connected by a link mechanism 14, is characterized in that so as to open and close the shell 11, 11 by the lifting of the lift frame 13 due to the expansion and contraction operation of the cylinder 12.

  A hammer grab according to claim 1, wherein the hammer grab according to claim 1 is disposed between the cylindrical base frame 5 and the cylindrical main body frame 9 in a radially outward direction with respect to the inner peripheral surface of the casing C driven into the ground. It has a plurality of pushers 53 for integrating the cylindrical base frame 5 and the cylindrical main body frame 9 with the casing C by being able to move forward and backward inward and in pressure contact with the inner peripheral surface of the casing C when moving forward. A stabilizer 15 is provided.

  A third aspect of the present invention is the hammer grab according to the first aspect, wherein the inner peripheral surface of the outer cylinder member 8 or the small-diameter shaft portion 4 is provided between the small-diameter shaft portion 4 and the outer cylinder member 8 of the swivel mechanism 7. An O-ring 49 fitted into an annular groove 48 provided on the outer peripheral surface of the O-ring 49 and engages with an inner peripheral surface of the O-ring 49 so as to be in sliding contact with the outer peripheral surface of the small-diameter shaft portion 4 or the outer periphery of the O-ring 49 A seal ring 33 including a cap seal 50 engaged with the surface and slidably contacting the inner peripheral surface of the outer cylinder member 8 is interposed.

  The effect of the invention by the above solution will be described with reference numerals of the embodiments described later. According to the invention of claim 1, the cylindrical base frame 5 and the cylindrical main body frame 9 are suspended shafts. 2 When the cast-in-place pile method or other foundation work is performed, the excavation and excavation work inside the casing and the excavation work of existing piles cut or crushed in the middle are performed in parallel with the rotary excavation of the casing. Even if the shell 11 contacts the rotating casing C, only the cylindrical base frame 5 and the cylindrical main body frame 9 rotate together, so that the suspension shaft body 2 is held in a non-rotating state. There is no risk of wires and hydraulic piping tubes being twisted and damaged.

  In the hammer grab 1, the large diameter shaft portion is suspended by hanging down a cylindrical base frame 5 that is rotatably connected to the upper diameter large shaft portion 3 of the suspension shaft 2 via a thrust bearing 6. 3 is made to bear most of the load of the hammer grab 1, and the lower-diameter small-shaft portion 4 of the shaft 2 for suspension is used as the inner cylinder member of the swivel mechanism 7 and the small-diameter shaft portion 4 Since the swivel mechanism 7 is composed of the outer cylindrical member 8 that is rotatably fitted, the small-diameter shaft portion 4 has a diameter that can form an oil passage in the axial direction thereof. The diameter of the large shaft portion 3 can be made sufficiently small, and therefore the frictional resistance between the small diameter shaft portion 4 and the outer cylinder member 8 can be made as small as possible. There is no risk of twisting the hanging wire, hydraulic piping tube, etc.

  According to the hammer grab 1 of the invention according to claim 2, the cylindrical base frame 5, the machine frame 16 of the stabilizer 15 and the cylindrical main body frame 9 are rotatable with respect to the hanging shaft body 2. When removing an existing pile that has been buried, the upper end of the existing pile is held by the shells 11, 11 and the stabilizer 15 is operated to press the pusher 53 against the inner peripheral surface of the casing C. Thus, with the cylindrical base frame 5 and the cylindrical main body frame 9 being integrated with the casing C via the machine frame 16 of the stabilizer 15, the casing C is pulled out while being rotated in the pulling direction by the all-round rotation drive device. The existing piles held by the shells 11 and 11 can be discharged to the ground, and the existing piles can be removed by repeating such operations. In this case, the pulling force of the casing C is several times that when the hammer grab 1 is lifted with a wire and the pile is pulled out, which is extremely strong.

  According to the third aspect of the present invention, the swivel mechanism 7 is provided between the small diameter shaft portion 4 and the outer cylinder member 8 on the inner peripheral surface of the outer cylinder member 8 or the outer peripheral surface of the small diameter shaft portion 4. An O-ring 49 fitted in the annular groove 48 and engaged with the outer peripheral surface of the small-diameter shaft portion 4 by engaging with the inner peripheral surface of the O-ring 49 or engaged with the outer peripheral surface of the O-ring 49 Since the seal ring 33 including the cap seal 50 slidably in contact with the inner peripheral surface of the outer cylinder member 8 is interposed, the sliding resistance can be reduced by the cap seal 50, and the small shaft of the swivel mechanism 7 can be reduced. The frictional resistance between the portion 4 and the outer cylinder member 8 can be effectively reduced, and the service life of the O-ring 49 can be extended by the cap seal 50.

It is a partial cross section front view of the hammer grab by one Embodiment of this invention. FIG. 2 is an enlarged sectional view taken along line XX in FIG. 1. (a) is a front view of the shaft body and swivel mechanism part of the hammer grab shown in FIG. 1, and (b) is a side view. (a) is a front view showing a base frame body with a bottom plate of a cylindrical base frame, (b) is a cross-sectional view along line YY of (a), (c) is a bottom view, and (d) is a lid plate from the inside. (E) is a sectional view taken along the line ZZ of (d), and (f) is an explanatory sectional view showing a state in which the connecting plate of the outer cylinder member is held between the holding plates of the lid plate. FIG. 3 is a partially enlarged view of FIG. 2. (a) is a longitudinal sectional view showing a part of a hammer grab according to another embodiment of the present invention, and (b) is an end view of the hammer grab part shown in (a) as viewed from above. It is explanatory drawing of the state which is excavating the ground using the conventional hammer grab.

  A preferred embodiment of the present invention will be described below with reference to the drawings. A hammer grab 1 shown in FIGS. 1 to 4 has an upper diameter large shaft portion 3 and a lower diameter as shown in FIG. A suspension shaft body 2 including a small shaft portion 4 is provided, and a cylindrical base frame 5 that is rotatably connected via a thrust bearing 6 is suspended from the large-diameter shaft portion 3 of the suspension shaft body 2. The small diameter shaft portion 4 is rotatably fitted with an outer cylinder member 8 constituting a swivel mechanism 7 using the small diameter shaft portion 4 as an inner cylinder member. As shown in FIG. 2, a cylindrical main body frame 9 is suspended and connected via a machine frame 16 of a stabilizer 15, a shell mounting frame 10 is connected to the lower portion of the cylindrical main body frame 9, and a pair of shells 11 is connected to the shell mounting frame 10. , 11 are pivotally mounted, and a cylinder opening / closing drive cylinder 12 is concentrically installed in the cylindrical main body frame 9 and is moved up and down below. 13 is provided so as to be able to move up and down, the lifting frame 13 is connected to the lower end side of the cylinder 12, the lifting frame 13 and the shells 11, 11 are interlocked and connected by a link mechanism 14, and the lifting frame 13 by the expansion and contraction operation of the cylinder 12. The shells 11 are opened and closed by raising and lowering.

  The structure of the hammer grab 1 will be described in more detail. As shown in FIGS. 1 to 3, the suspension shaft 2 has pressure oil for the shell opening / closing drive cylinder 12 on the upper end side of the large-diameter shaft portion 3. Supply and discharge oil ports 17 and 18 (see FIG. 2 and FIG. 3B)) and supply and discharge oil ports for supplying and discharging pressure oil to the pusher drive cylinder 35 of the stabilizer 15 described later. 19 and 20 (see (a) and (b) of FIG. 3) are provided, and these oil supply / discharge oil ports 17, 18, 19, and 20 are provided from the upper side large shaft portion 3 to the lower portion as shown in FIG. Oil passages 21, 22 provided over the small-diameter side shaft portion 4 (FIG. 2 shows only the oil passages 21, 22 of the oil supply / discharge ports 17, 18, The oil passage is omitted)), and the oil supply / discharge port and pusher drive on the shell opening / closing drive cylinder 12 side through the swivel mechanism 7 It is communicatively connected to the use cylinder 35 side of the supply oil outlet. A bolt insertion hole 40 (see FIG. 3) for attaching a shackle is provided at the upper end portion of the large-diameter shaft portion 3, and a shackle 24 is attached to the shackle 24 by inserting a bolt 23 therethrough. A hanging wire (not shown) is attached.

  As shown in FIGS. 2 and 3, the cylindrical base frame 5 includes an upper cylindrical frame 5a, a base frame main body 5b connected to a lower end portion of the upper cylindrical frame 5a by a bolt 41 and continuously suspended, and an upper cylindrical frame. The upper end plate 5c is fixed to the upper end portion of the frame 5a with bolts 42, and the bottom plate 5d is fixed to the lower end portion of the base frame main body 5b. The upper cylindrical frame 5a is an upper portion of the suspension shaft 2. A thrust bearing 6 is interposed between the upper cylindrical frame 5a and the lower-end side flange 3o of the large-diameter shaft 3 so as to be fitted on the large-diameter side shaft 3, and the flange 3a and the upper cylinder A radial bearing 43 is interposed between the frame 5a. A plurality of reinforcing ribs 44 and 47 are arranged at appropriate intervals on the outer circumferences of the upper cylindrical frame 5a and the base frame main body 5b.

  Further, as shown in FIGS. 4A and 4B, the base frame main body 5b has working openings 37 at symmetric positions on both sides in the diameter direction, and each opening 37 has a rectangular frame-shaped opening frame 57. Is attached to the opening frame 57 via a rubber packing (not shown) (see FIG. 3). 4A and 4B show a state in which an opening frame 57 is attached to the opening 37 of the base frame body 5b. 4D is a front view of the cover plate 38 as viewed from the inside, and FIG. 4E is a sectional view taken along the line ZZ of FIG. 4D. The cover plate 38 has a socket 58 for connecting a hydraulic piping tube. A pair of clamping plates 59, 59 are provided on the inner surface side of the lid plate 38 so as to insert and clamp the connecting plate 36 projecting outward from the outer cylinder member 8 of the swivel mechanism 7. Projected in the direction. The two lid plates 38, 38 attached to the opening frames 57, 57 on both sides are completely the same, and are attached upside down as shown in FIG.

  The lower-side-diameter small shaft portion 4 of the suspension shaft body 2 has a diameter that is about ½ of the diameter of the upper-side-diameter large shaft portion 3. The swivel mechanism 7 is constituted by the radial bearing 45 and the outer cylinder member 8 fitted through the seal ring 33. In this swivel mechanism 7, as shown in FIG. 2, the lower end portions of the oil passages 21, 22 on the shell opening / closing drive cylinder side provided in the small-diameter shaft portion 4 are on the inner peripheral surface of the outer cylinder member 8. It is connected to the branch ports 27 and 28 of the outer cylinder member 8 through the circumferential communication passages 25 and 26, and the shell opening / closing drive from the branch ports 27 and 28 through a hydraulic piping tube (not shown). The cylinder 12 is connected to the cylinder body 12a. Further, the pusher driving cylinder side oil passage (not shown) of the stabilizer 15 provided in the small-diameter shaft portion 4 is connected to the inner peripheral surface of the outer cylinder member 8 through communication passages 29 and 30. The outer cylinder member 8 is connected to the branch ports 31 and 32, and the branch ports 31 and 32 are connected to pusher drive cylinders 34 and 34 of the stabilizer 15 to be described later via hydraulic piping tubes (not shown), respectively. Yes.

  In order to attach the outer cylinder member 8 of the swivel mechanism 7 to the small-diameter shaft portion 4, as shown in FIG. 2, the outer cylinder member 8 provided with radial bearings 45 on both upper and lower ends is attached to the small-diameter shaft portion 4. After fitting from below, the support plate 54 is fastened to the lower end surface of the small-diameter shaft portion 4 with bolts (not shown), and the inner ring portion of the lower end side radial bearing 45 is supported from below, so that the outer cylinder What is necessary is just to hold | maintain the member 8 rotatably with respect to the small diameter shaft part 4, and to attach and fix the lower cover 55 to the lower end surface of the outer cylinder member 8 with the volt | bolt 56 after that. When the cover plate 38 is attached to the opening frame 57 of the base frame main body 5b, the holding plates 59, 59 protruding from the inner surface of the cover plate 38 are fitted and held to the connecting plate 36 of the outer cylinder member 8. Thus, the cylindrical base frame 5 and the outer cylinder member 8 are connected so as to be integrated.

  As described above, the outer cylinder member 8 that is rotatably fitted to the small-diameter shaft portion 4 of the suspension shaft body 2 and constitutes the swivel mechanism 7 together with the small-diameter shaft portion 4 is provided on the base frame main body 5b side. The cylindrical base frame 5 rotates integrally with the clamping plates 59 and 59 and the connecting plate 36 on the outer cylinder member 8 side sandwiched between the clamping plates 59 and 59.

  As shown in FIG. 1, the stabilizer 15 includes a cylindrical machine frame 16 having a peripheral wall 16 a having a diameter smaller than the outer diameter of the shell mounting frame 10, and pushers are provided on the lower side and the upper side of the machine frame 16. The drive double hydraulic cylinders 34, 34 for driving are arranged so as to cross in a cross shape in plan view, and pushers 53, 53 are shown at both ends of the double hydraulic cylinder 34 at each stage. In this way, they are interlocked and connected at a position protruding to the outside of the machine casing 16.

  Thus, the four pushers 53, which are the combination of the two lower pushers 53, 53 and the two upper pushers 53, 53, are composed of the lower return double cylinder 34 and the upper return double hydraulic cylinder 34. Are simultaneously driven forward and backward in the radial direction, and projecting from the position indicated by the solid line in FIG. 1 at the time of forward driving in the radial direction, and press-contacted to the inner peripheral surface of the casing C as shown by the phantom line, thereby the machine frame 16 So that the cylindrical base frame 5 and the cylindrical main body frame 9 are integrated with the casing C, and retracted to the original position during the backward driving inward in the radial direction so as to cut the edge with the casing C. It has become.

  As shown in FIG. 2, the bottom plate 5 d of the cylindrical base frame 5 is connected to the upper end of the machine frame 16 of the stabilizer 15 by a bolt 46 via an attachment member 39, whereby the machine frame 16 is connected to the cylindrical base frame 5. It is one. Further, as can be seen from FIG. 1, the lower end portion of the machine frame 16 of the stabilizer 15 is connected to the upper end portion of the cylindrical main body frame 9, whereby the machine frame 16 is integrated with the cylindrical main body frame 9. . Therefore, the cylindrical base frame 5, the machine frame 16 of the stabilizer 15, the cylindrical main body frame 9, and the shell mounting frame 10 are connected to each other to form an integral body.

  As shown in FIG. 1, the upper end of the cylinder body 12 a of the shell opening / closing drive cylinder 12 is connected and fixed to the lower end side of the machine frame 16, and the lower end of the piston rod 12 b is the cylindrical body of the cylindrical body frame 9. 9a is pivotally attached to an elevating frame 13 provided so as to be movable up and down. A rod mounting member 51 is provided at the lower end of the lifting frame 13, and one end of each of the pair of connecting rods 52, 52 constituting the link mechanism 14 is pivotally attached to both ends of the rod mounting member 51. The other end portions of the connecting rods 52 and 52 are pivotally attached to the swing levers 11a and 11a of the shells 11 and 11, respectively. Therefore, as shown in FIG. 1, when the piston rod 12a of the shell opening / closing drive cylinder 12 is extended and the elevating frame 13 is at the lower limit position as shown by the solid line, the shells 11 and 11 are in the open posture. Yes, when the piston rod 12b of the cylinder 12 contracts from this state and the elevating frame 13 rises to the upper limit position as shown in the phantom line, both shells 11 and 11 are brought into a closed posture by the link mechanism 14.

  FIG. 5 is an enlarged view of the mounting portion of the seal ring 33 interposed between the lower-side-diameter small shaft portion 4 of the suspension shaft body 2 constituting the swivel mechanism 7 and the outer cylinder member 8. Each seal ring 33 is engaged with an O-ring 49 fitted in an annular groove 48 provided on the inner peripheral surface of the outer cylinder member 8, and the outer periphery of the small-diameter shaft portion 4 by engaging with the inner peripheral surface of the O-ring 49. The cap seal 50 is in sliding contact with the surface. When the seal portion is at a high pressure, it is desirable to use the cap seal 50 and the backup ring in combination with each seal ring 33. In this case, the backup ring is attached along the side wall of the annular groove 48. The O-ring 49 is made of nitrile rubber or fluorine rubber, and the cap seal 50 is made of fluorine resin or the like.

  The seal ring 33 according to this embodiment includes an O-ring 49 fitted in an annular groove 48 provided on the inner peripheral surface of the outer cylinder member 8 and a small-diameter shaft engaged with the inner peripheral surface of the O-ring 49. The seal ring 33 is provided on the outer peripheral surface of the small-diameter shaft portion 4 of the suspension shaft 2 although not shown in the figure. An O-ring 49 fitted into the annular groove 48 and a cap seal 50 engaged with the outer peripheral surface of the O-ring 49 and slidably contacting the inner peripheral surface of the outer cylinder member 8 may be used.

  FIG. 6A is a longitudinal sectional view showing a main part of a hammer grab according to another embodiment of the present invention, and FIG. 6B is a plan view thereof. In the hammer grab according to this embodiment, a thickened flange portion 3a is protruded from the upper end portion of the large-diameter shaft portion 3 of the suspension shaft 2, and a thrust bearing 6 is provided on the expanded flange portion 3a. This is almost the same as the hammer grab of the embodiment shown in FIGS. 1 and 2 except that the cylindrical base frame 5 is rotatably connected in a hanging manner and the enlarged flange portion 3a is lifted.

  That is, four hanging rings 60 are attached to the upper surface side of the enlarged diameter flange portion 3a projecting from the upper end portion of the large diameter shaft portion 3, for example, at intervals of 90 ° in the circumferential direction, and the enlarged diameter flange portion 3a. A thrust bearing 6 is interposed between the upper end of the cylindrical base frame 5 and a cover 61 is attached to the peripheral edge of the enlarged diameter flange portion 3a. The cylindrical base frame 5 of this embodiment includes a base frame main body 5b and a bottom plate 5d fixed to the lower end portion of the base frame main body 5b. In FIG. 6B, 62 is a bolt insertion hole for bolting the inner ring side of the thrust bearing 6 to the enlarged diameter flange portion 3a, and 63 is an outer peripheral mounting ring portion 64 of the enlarged diameter flange portion 3a. It is a bolt insertion hole for bolting to. As shown in FIG. 6A, the swivel mechanism 7 of the hammer grab 1 of this embodiment is also composed of a small-diameter shaft portion 4 of the hanging shaft body 2 and an outer cylinder member 8. As shown in FIG. Since the configuration is the same as that of the hammer grab of the embodiment shown in FIG.

  In using the hammer grab, a suspension wire (not shown) suspended from a crane is attached to a plurality of suspension rings 60 provided on the diameter-enlarged flange portion 3a of the large-diameter shaft portion 3 of the suspension shaft 2. When the shaft 2 for suspension is suspended by this wire, most of the load of the hammer grab 1 is cylindrical via the thrust bearing 6 as in the hammer grab of the embodiment shown in FIGS. It is borne by the large-diameter shaft portion 3 of the suspension shaft 2 that supports the base frame 5 in a freely rotatable manner, in particular, the enlarged-diameter flange portion 3a. Since the hammer grab of the embodiment of FIG. 6 is adapted to be hung by attaching suspension wires from a crane to a plurality of suspension rings 60 provided on the diameter-enlarged flange portion 3a of the large-diameter shaft portion 3. The suspended state of the hammer grab 1 is stable, and the work becomes easy. Further, as can be seen from FIG. 6, the structure of the cylindrical base frame 5 and the connecting structure between the large-diameter shaft portion 3 of the hanging shaft body 2 and the cylindrical base frame 5 can be simplified, so that the manufacture becomes easy. .

  As described above, when the hammer grab 1 having the configuration described with reference to FIGS. 1 to 6 is used for removing an existing pile buried in the ground, for example, the conventional hammer grab H shown in FIG. 7 is used. As in the case of use, the casing C is rotationally press-fitted by an all-around rotation drive device, driven into the ground, and the suspension wire hanging from the jib tip of the crane is attached to the shackle 24 or suspension of the suspension shaft 2. The hammer grab 1 is suspended and attached to the ring 60 in a state where the suspension shaft 2 is suspended by a wire. At this time, most of the load of the hammer grab 1 is borne by the large-diameter shaft portion 3 of the suspension shaft body 2 that rotatably supports the cylindrical base frame 5 via the thrust bearing 6.

  The hammer grab 1 with the suspension shaft 2 suspended by the suspension wire is lowered into the casing C with the shells 11, 11 open, and the upper end of the existing pile in the casing C. Is held by the shells 11 and 11 in the closed posture, and the stabilizer 15 is operated to press the pusher 53 against the inner peripheral surface of the casing C as shown in FIG. With the cylindrical base frame 5, the cylindrical main body frame 9, and the shell mounting frame 10 being integrated with the casing C, the casing 11 is pulled out while rotating the casing C in the pulling direction by the all-around rotation drive device. The existing piles that have been gripped are twisted and discharged to the ground, and the existing piles are removed by repeating these operations. In this case, the pulling force of the casing C is several times that when the hammer grab 1 is lifted with a wire and the pile is pulled out, which is extremely strong.

  In the use of the hammer grab 1 as described above, even if the cylindrical base frame 5, the cylindrical main body frame 9 and the shell mounting frame 10 are rotated in a state integrated with the casing C via the machine frame 16 of the stabilizer 15, Since the suspension shaft 2 suspended from the crane by the suspension wire does not rotate, there is no possibility that the suspension wire, the hydraulic piping tube, or the like is twisted and cut or damaged. Moreover, in the hammer grab 1, the large diameter shaft is provided by suspending the cylindrical base frame 5 that is rotatably connected to the upper large diameter shaft portion 3 of the suspension shaft 2 via the thrust bearing 6. The portion 3 is made to bear most of the load of the hammer grab 1, and the lower-diameter small shaft portion 4 of the suspension shaft 2 is used as an inner cylinder member of the swivel mechanism 7, and the small-diameter shaft portion 4 and this Since the cylinder supply / discharge oil swivel mechanism 7 is constituted by the outer cylinder member 8 that is rotatably fitted to the shaft, the small-diameter shaft portion 4 has a diameter that can form an oil passage in the axial direction thereof. , The diameter of the large-diameter shaft portion 3 can be made sufficiently small, and therefore the frictional resistance between the small-diameter shaft portion 4 and the outer cylindrical member 8 can be minimized, so There is no risk of the shaft 2 rotating together, and the suspension wire, hydraulic piping tube, etc. are twisted There is no danger, such as.

  Further, a seal ring 33 interposed between the lower-side small-diameter portion 4 of the swivel mechanism 7 and the outer cylinder member 8 is fitted into an annular groove 48 provided on the inner peripheral surface of the outer cylinder member 8. The O-ring 49 and the cap seal 50 that engages with the inner peripheral surface of the O-ring 49 and slidably contacts the outer peripheral surface of the small-diameter shaft portion 4. The frictional resistance between the small-diameter shaft portion 4 of the swivel mechanism 7 and the outer cylinder member 8 can be effectively reduced, and the service life of the O-ring 49 is extended by the cap seal 50. Can do.

  In the hammer grab 1 of the above-described embodiment, the stabilizer 15 is provided between the cylindrical base frame 5 and the cylindrical main body frame 9, but without providing such a stabilizer 15, the lower end of the cylindrical base frame 5 is provided. You may make it connect the upper end part of the cylindrical main body frame 9 directly to a part. According to the hammer grab 1 having such a configuration, the cylindrical base frame 5, the cylindrical main body frame 9 and the shell mounting frame 10 are rotatable with respect to the suspension shaft 2, so that the cast-in-place pile method and other foundations are used. During construction, the shell 11 and the shell mounting frame 10 are attached to the rotating casing C when performing excavation and earthing work inside the casing and picking up existing piles cut or crushed in the middle of the casing in parallel with the rotary excavation of the casing. Even if they come into contact with each other, only the cylindrical base frame 5, the cylindrical main body frame 9 and the shell mounting frame 10 rotate together, so that the suspension shaft body 2 is held in a non-rotating state. There is no risk of damage due to twisting.

DESCRIPTION OF SYMBOLS 1 Hammer grab 2 Suspension shaft body 3 Large diameter shaft portion 3a of suspension shaft body Large diameter flange portion 4 of large diameter shaft portion Small diameter shaft portion 5 of suspension shaft body 5 Cylindrical base frame 6 Thrust bearing 7 Swivel mechanism 8 Outer cylinder member 9 Tubular body frame 10 Shell mounting frame 11 Shell 12 Shell opening / closing drive cylinder 13 Lifting frame 14 Link mechanism 15 Stabilizer 33 Seal ring 48 Annular groove 49 O-ring 50 Cap seal 53 Stabilizer pusher

Claims (3)

  A suspension shaft body 2 composed of an upper large diameter shaft portion 3 and a lower small diameter shaft portion 4 is provided, and the large shaft portion 3 of the suspension shaft body 2 is rotated via a thrust bearing 6. A cylindrical base frame 5 that is freely connected is suspended, and an outer cylindrical member 8 that constitutes a cylinder supply / discharge oil swivel mechanism 7 is rotatable on the small-diameter shaft portion 4 by using the small-diameter shaft portion 4 as an inner cylinder member. The cylindrical main body frame 9 is suspended and connected to the lower part of the cylindrical base frame 5, and a plurality of shells 11, 11 are pivotally attached to the lower end side of the cylindrical main body frame 9. A shell opening / closing drive cylinder 12 is installed in the frame 9, and an elevating frame 13 is provided below the cylinder 9. The cylinder 12 is linked to the elevating frame 13, and the elevating frame 13 and the shells 11, 11 are linked to each other. 14 and the shell 11, Hammer grab which is adapted to open and close the 1.   Between the cylindrical base frame 5 and the cylindrical main body frame 9, the casing can be moved forward and backward in the radial direction and inward with respect to the inner peripheral surface of the casing C driven into the ground. The hammer grab according to claim 1, further comprising a stabilizer (15) having a plurality of pushers (53) for integrating the cylindrical base frame (5) and the cylindrical main body frame (9) with the casing (C) in pressure contact with the C inner peripheral surface.   Between the small-diameter shaft portion 4 and the outer cylinder member 8 of the swivel mechanism 7, an O-ring fitted into an annular groove 48 provided on the inner peripheral surface of the outer cylinder member 8 or the outer peripheral surface of the small-diameter shaft portion 4. 49 and the inner peripheral surface of the O-ring 49 to engage with the outer peripheral surface of the small-diameter shaft portion 4 or engage with the outer peripheral surface of the O-ring 49 to the inner peripheral surface of the outer cylinder member 8. The hammer grab according to claim 1, wherein a seal ring 33 comprising a cap seal 50 in sliding contact is interposed.

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