Hang Da Ji

Abstract

To provide a pile driver with a stay bracket that can be easily and safely attached to and detached from the reader.SOLUTION: In a pile driver in which a reader 18 and a backstay 28 are erected from a collapsed state after being assembled in front of a base machine, a stay bracket 36 removably provided on the back of the reader 18 to hold a pair of left and right back stays 28 in a collapsed state has a bar 38 provided with a reader mounting part 37 in the middle portion in a longitudinal direction, a stay holding part 39 provided on both ends of the bar 38, and a connecting part 40 provided in an area C2 including the leader attachment portion 37 among the areas C1, C2, and C3 that divide the bar 38 into three equal parts in the longitudinal direction, and which connects the stay bracket 36 as two separate parts BL, BR separable from each other depending on the presence of the leader attachment portion 37. The bar 38 is provided with a plurality of suspensions 41, 42, 43 corresponding to the center of gravity that fluctuates between the connected state of the stay bracket 36 and its disconnected state.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a pile driver, and more particularly to a three-point support type pile driver equipped with a pair of left and right backstays that support a leader erected at the front of a base machine. [Background technology]

[0002] In a three-point support pile driver, the leader and backstay are placed in front of the base machine and assembled on the ground, and then erected on the base machine using the pendant rope and the derrick rope that are stretched across the tip of the leader. When assembling such a long, heavy object, the backstay, whose lower end is in a free state, slides on the ground as it is erected, and if excessive force is applied to it, it may be damaged or its durability may be reduced. In response to these assembly problems, a pile driver equipped with a stay bracket for holding the backstay on the back of the leader has been developed and is now in use (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-227202 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned stay bracket becomes unnecessary after the three-point support by the leader and the backstay is established, so it is necessary to remove it from the leader before it interferes with the pile driving work. However, when the leader is in the upright state, it is difficult for a crane to approach, and in addition, various winch ropes passing through the back of the leader become an obstacle, making the installation and removal of the stay bracket difficult.

[0005] In addition, when attaching the above-mentioned stay bracket to a leader that has been assembled on the ground, the pendant rope and the hoisting rope are stretched above the leader, and in particular, since the middle sheave is located above the stay bracket attachment position, it was difficult to hoist the stay bracket using a crane.

[0006] Therefore, an object of the present invention is to provide a pile driver equipped with a stay bracket that can be easily and safely attached and detached to a leader. [Means for solving the problem]

[0007] In order to achieve the above object, the pile driver of the present invention comprises a leader that is mounted on the front of a base machine so as to be able to rise and fall, and a pair of left and right backstays that support the leader from the rear, and the leader and the backstays are assembled on the ground in front of the base machine and then raised from a lying down state to be erected. The back of the leader is provided with a detachable stay bracket that holds the pair of left and right backstays in the lying down state, and the stay bracket has a bar with a leader attachment part in the middle of its length, stay holding parts provided on both ends of the bar, and connecting parts that are provided in an area that includes the leader attachment part among areas that divide the bar into three equal parts in the length direction, and that connect the stay bracket into two divided bodies that can be separated from each other depending on the presence or absence of the leader attachment part, and the bar is provided with a plurality of hanging parts according to the center of gravity that changes depending on whether the stay bracket is in a connected state or not.

[0008] In addition, the multiple hanging parts are characterized in that they consist of an overall hanging part for hanging the stay bracket in a connected state and an individual hanging part for hanging the divided body alone, and the individual hanging parts are composed of an individual hanging part for ground assembly and an individual hanging part for detachment, the hanging directions of which are perpendicular to each other.

[0009] Furthermore, the connecting portion is characterized by having a connecting and overlapping portion formed by overlapping parts of the two divided bodies, and a connecting pin that passes through the connecting and overlapping portion and is arranged in a direction parallel to the leader.

[0010] In addition, the reader attachment portion includes an attachment base that is fixed to the rear surface of the reader, and A pair of mounting arms are inserted into a pair of forks on the bar. It is characterized by having an overlapping mounting overlapping portion and a mounting pin that penetrates the mounting overlapping portion and is arranged horizontally perpendicular to the leader, and the mounting base is provided with a seat surface that supports the bar in a surface contact state. Effect of the Invention

[0011] According to the pile driver of the present invention, the stay bracket that can be attached to the back of the leader has a connecting part for dividing it into two parts with and without the leader attachment part, so the leader attachment part does not become a weak part against bending loads, and the backstay can perform its supporting function in a desirable manner. Moreover, since the connecting part is provided in the middle area including the leader attachment part among the areas divided into three equal parts in the longitudinal direction of the bar, by using a hanging part according to the center of gravity of each divided body, it becomes possible to perform the hanging operation without interference with the various ropes that pass through the back of the leader, and the work of attaching and detaching the stay bracket can be performed safely one by one in order.

[0012] In addition, the individual hanging parts for hanging the divided bodies individually consist of individual hanging parts for ground assembly and individual hanging parts for removal and installation, with the hanging directions perpendicular to each other, so that the stay bracket can be safely removed and installed whether the leader is in a laid-down or upright position.

[0013] Furthermore, since the connecting portion is provided with a connecting overlapping portion formed by a part of each divided body and a connecting pin disposed penetrating the connecting overlapping portion, a simple pin-type connecting structure suitable for work sites where speed is required can be obtained, and the stay brackets can be smoothly connected and disconnected. In particular, since the connecting pin is disposed in a direction parallel to the leader, the connecting overlapping portion that overlaps above and below can be used when the leader is in an upright position, so that the pin holes can be easily made coaxial during the hanging operation by inching, and the work of inserting and removing the connecting pin is easy and safe.

[0014] In addition, the leader mounting part is equipped with a pin-type connection structure in which the mounting pin is arranged horizontally perpendicular to the leader, and a mounting base fixed to the back part of the leader, and the bar is supported by surface contact with the seat provided on the mounting base, so that it is possible to reduce the load on the mounting pin when supporting the weight of the backstay, and it is possible to achieve a smaller and lighter mounting pin, and thus a smaller leader mounting part as a pin-type connection structure. In particular, the pin hole can be aligned by a simple hanging action of simply placing the bar on the seat, which contributes to safety and work efficiency when installing the stay bracket. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a side view showing an example of the present invention in which a leader and a backstay of a pile driver are assembled on the ground and placed in a laid-down state. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. 4 is a cross-sectional view of FIG. [Figure 6] FIG. 11 is an explanatory diagram of the operation of removing one of the divided bodies in the operation of removing and attaching the stay bracket. [Figure 7] This is an explanatory diagram of the hanging operation using an individual hanging part for detachment on one side. [Figure 8]FIG. 11 is an explanatory diagram of the operation of removing the other divided body in the operation of removing and attaching the stay bracket. [Figure 9] This is an explanatory diagram of the hanging operation using the other side detachable individual hanging part. [Figure 10] FIG. 4 is a side view of the pile driver in an assembled state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Figures 1 to 10 show one embodiment of the pile driver of the present invention. As shown in Figure 10, the pile driver 11 has a base machine 14 formed by mounting an upper rotating body 13 rotatably on a lower traveling body 12 equipped with crawlers. The upper rotating body 13 has a winch mounting section (see Figure 6, etc.) 15 mounted with various winch devices including a hoisting winch, a main hoisting winch, and an auxiliary hoisting winch in the center of the machine frame, a cab 16 for an operator to sit in on the right side, and a power section 17 mounted with an engine, a hydraulic pump, etc. on the left side.

[0017] A leader bracket 20 to which a leader 18 and front jacks 19, 19 are attached is provided at the front of the upper rotating body 13. A movable gantry 21 is provided above the rear of the upper rotating body 13, and a counterweight 22 is mounted at the rear end of the upper rotating body 13. Rear jacks 23, 23 and stay mounting parts 24, 24 are provided on both sides of the frame on which the counterweight 22 is mounted.

[0018] The leader 18 has a cylindrical shape with multiple leader members 18b connected to the upper part of a leader base member 18a that is pivotally supported on the leader bracket 20 so as to be swingable in the front-rear and left-right directions, and a stay holder 25 is provided in the middle. A hoisting rope 26 from the hoisting winch is connected to the rear part of the stay holder 25 via a pendant rope 27, and the tips of a pair of left and right back stays 28, 28 that are erected on the stay attachment parts 24, 24 are also connected thereto.

[0019] The hoisting rope 26 rises upward from the hoisting winch, passes through a guide sheave provided at the upper end of the gantry 21, and is wound multiple times around multiple sheaves of the middle sheave block MB and multiple sheaves of the gantry sheave block GB provided at the upper end of the gantry 21.The hoisting rope 26 is configured so that by operating the hoisting winch, the leader 18 can be raised or lowered via the hoisting rope 26, middle sheave block MB, and pendant rope 27.

[0020] The backstay 28 has a cylindrical shape that connects a tip stay member 28a, multiple intermediate stay members 28b, and a stay cylinder (hydraulic cylinder) 29, and while supporting the leader 18 from the rear, the extension and contraction action of the stay cylinders 29, 29 makes it possible to adjust the inclination of the leader 18 in the forward / backward or left / right direction (vehicle width direction).

[0021] On the upper surface of the leader bracket 20, there are provided a main winding guide sheave 31 for guiding the main hoisting rope 30 from the main hoisting winch, and an auxiliary winding guide sheave 33 for guiding the auxiliary hoisting rope 32 from the auxiliary hoisting winch. Each rope 30, 32 rises at the main winding guide sheave 31 and the auxiliary winding guide sheave 33, passes through the back surface of the leader 18, and hangs down to the front part of the leader 18 via an intermediate guide sheave 34 provided on the stay holder 25 and a top sheave 35 provided at the upper end of the leader 18, with the tip of the main hoisting rope 30 attached to an auger (not shown) that can be raised and lowered along the front surface of the leader 18, and the tip of the auxiliary hoisting rope 32 attached to a lower guide (not shown).

[0022] When the pile driver 11 thus constructed is assembled and used, the leader 18 and the backstay 28 are placed in front of the base machine 14 and assembled on the ground, and the backstay 28 is temporarily assembled with the tip stay member 28a connected to the stay holder 25, and the stay cylinder 29 at the lower end is placed in a free state. If the leader 18 and the backstay 28, which are in a collapsed state, are erected together, or conversely, the stay cylinder 29 is collapsed from the upright state, the stay cylinder 29 may slide on the ground and move, resulting in damage or a decrease in durability. In addition, when the leader 18 is hoisted by an accompanying crane, the pile driver body cannot travel if the lower end of the stay cylinder 29 is on the ground, so the accompanying crane must be moved according to the leader elevation angle, which requires a large assembly space.

[0023] In order to solve these assembly problems, the pile driver 11 is provided with a removable stay bracket 36 as an assembly jig on the back of the leader 18, i.e., on the surface facing vertically upward in the laid-down state, as shown in Figures 1 and 2, which acts like a balance beam with the attachment point to the leader 18 as a fulcrum, creating a stable stay holding state that is approximately horizontal (Figure 1) and approximately A-shaped (Figure 2) in plan view and symmetrical. This allows the lower end of the backstay 28, which follows the raising operation of the leader 18, to maintain a constant height above the ground.

[0024] Incidentally, after the three-point support by the leader 18 and the back stays 28, 28 is established, the stay bracket 36 is left at a height of about 10 m, so it is necessary to remove it from the leader 18 before it interferes with the pile driving work. However, when the leader 18 is in an upright state, it is difficult for a crane to approach, and in addition, as can be seen from FIG. 10, various ropes 30, 32 passing through the back of the leader 18 become an obstacle, making the installation and removal work of the stay bracket 36 at a high place even more difficult. In addition, when the leader is in a ground-assembled state, as can be seen from FIG. 1, the hoisting rope 26 and the pendant rope 27 are stretched above the leader 18, and in particular, the middle sheave block MB is located above the mounting base 49 described later, which makes it difficult to install and remove the stay bracket 36 by a crane. Therefore, the stay bracket 36 is provided with a split structure that allows such installation and removal work to be performed easily and safely.

[0025] As shown in Figures 3 to 5, the stay bracket 36 has a bar 38 with a leader mounting portion 37 in the middle (center) in the longitudinal direction, stay holding portions 39, 39 provided on both ends of the bar 38, and a connecting portion 40 provided in middle region C2 including the leader mounting portion 37 of regions C1, C2, C3 which divide the bar 38 into thirds in the longitudinal direction (Figure 5), and which connects the stay bracket 36 into two divided bodies BL, BR that can be separated from each other depending on the presence or absence of the leader mounting portion 37.

[0026] The bar 38 is made of H-shaped steel with a uniform cross section, and has its center of gravity at the center where the leader attachment part 37 is located, i.e., at approximately half the length, and has multiple reinforcing plates 38a welded to the inside (Figure 3). The flat flange underside ensures a stable seat on the ground or the loading platform, and functions as the attachment surface 38b when assembled to the leader 18.

[0027] The upper flange surface and reinforcing plate 38a of the bar 38 are provided with a plurality of suspending parts corresponding to the center of gravity that changes depending on whether the stay bracket 36 is in a connected state or not. These suspending parts are for suspending an object at two points by the hoisting operation of a crane, and consist of an overall suspending part 41 for suspending the stay bracket 36 in a connected state, and individual suspending parts for suspending the divided bodies BL and BR individually, i.e., a one-side individual suspending part 42 for suspending one divided body BL that does not have a leader mounting part 37, and an other-side individual suspending part 43 for suspending the other divided body BR that has a leader mounting part 37.

[0028] Each of the hanging parts 41, 42, 43 has a round hole in the hanging ear (plate piece) and the reinforcing plate 38a provided on the upper surface of the flange, and the hanging rope 44 is engaged in this round hole via a hanging tool. Here, while the overall hanging part 41 needs to be prepared only for transportation, the individual hanging parts 42, 43 are necessary not only for ground assembly but also when the leader is erected (detached), so in addition to providing individual hanging parts 42a, 43a for ground assembly that can be hung with the upper and lower surfaces of the flange of the bar 38 facing vertically, individual hanging parts 42b, 43b for detachment that can be hung with the upper and lower surfaces of the flange facing straight to the side are also provided. Specifically, the individual hanging parts 42a, 43a for ground assembly and the individual hanging parts 42b, 43b for removal and attachment have hanging directions (directions of the composite tension applied to the hanging points) that are perpendicular to each other, and of these, the individual hanging parts 42a, 43a for ground assembly are arranged side by side with the overall hanging part 41 on approximately the same line in the longitudinal direction of the bar 38.

[0029] As a result, when the stay bracket 36 is attached to and detached from the leader 18 in the leader-down state, the individual hanging parts 42a, 43a for ground assembly are specified, and the hanging ropes are hooked to them to hang each of the divided bodies BL, BR individually, although not shown in the figures. On the other hand, when the stay bracket 36 is attached or detached in the leader-up state, the flange upper and lower surfaces are turned from the vertical to the side, so that the individual hanging parts 42b, 43b for detachment are specified, and the hanging ropes 44 are hooked to them to hang each of the divided bodies BL, BR individually, as shown in Figures 7 and 9. In this way, the stay bracket 36 uses the optimal hanging parts 42, 43 both when the leader is upright and when the leader is down, and is hung in a stable position with the center of gravity of the object located at the midpoint below the hanging points.

[0030] The stay holding section 39 has a pair of brackets 45, 45 arranged opposite each other on the upper surface of the flange of the bar 38. The size and spacing of each bracket 45, 45 are set according to the outer diameter of the backstay 28, and the bracket 45 on one of the divided bodies BL is designed to be a common member with the individual suspension section 42a for ground assembly (Fig. 5). This bracket shape restricts the swinging of the backstay 28 caused by the raising and lowering movement of the leader 18, and a stable stay holding state is obtained. In addition, a safety rope 46 that confines the backstay 28 is provided between the upper ends of the brackets 45, 45, further increasing the safety of the holding means.

[0031] The connecting portion 40 includes a connecting overlap portion 47 formed by overlapping bifurcated portions 47a, 47b provided at the divided ends of each of the divided bodies BL, BR in a nested manner, and two connecting pins 48, 48 that pass through pin holes provided in the bifurcated portions 47a, 47b and are arranged in a direction parallel to the leader 18. As can be seen from Figure 5, each connecting pin 48 is inserted into two upper and lower pin holes set above the lower surface of the flange of the bar 38.

[0032] The leader mounting portion 37 comprises a mounting base 49 fixed to the rear portion of the leader 18, a mounting overlap portion 50 formed by inserting and overlapping a pair of mounting arms 50a, 50a provided on the mounting base 49 into a pair of bifurcated portions 50b, 50b provided on the bar 38, and two mounting pins 51, 51 which pass through pin holes provided in each of the mounting arms 50a and the bifurcated portions 50b and are arranged in a horizontal orthogonal direction to the leader 18 (orthogonal to the extension direction of the leader 18 and parallel (horizontal) to the ground).

[0033] As can be seen from Fig. 3, the mounting base 49 is provided with a seat 49a that is in surface contact with the mounting surface (flange underside) 38b of the bar 38 and supports the load in this state. The mounting pins 51 are inserted into two pin holes that extend coaxially in the width direction (in the direction of the paper in Fig. 3) set above the seat 49a and on the tip side of the leader 18 (left side in Fig. 3). With this pin-type connection structure, when assembling using the individual suspension parts for ground assembly 43a, the vertical positions of the pin holes are determined simply by abutting the mounting surface 38b of the bar 38 against the seat 49a, and then the hole positions are aligned by applying tension to the suspension rope 44 to eliminate horizontal misalignment, and the mounting pins 51 can be inserted.

[0034] When the pile driver 11 configured in this manner is used at a construction site, in order to clear transportation restrictions such as size and weight, the leader 18, backstay 28, stay bracket 36, etc. are disassembled into parts and transported separately from the base machine 14, and these are then assembled and used on site.

[0035] When the pile driver 11 is delivered to the site, first, the leader 18 and backstay 28 are assembled on the ground in front of the base machine 14. Specifically, the leader base member 18a is placed on the front part of the upper rotating body 13, and multiple leader members 18b supported by support stands 52 are connected in sequence starting from the leader base member 18a, and a top sheave 35 is attached to the top (Fig. 1). The backstay 28 connects the tip stay members 28a placed on the ground on both sides of the leader 18, multiple middle stay members 28b, and a stay cylinder 29 in a rod-like shape.

[0036] Next, the stay bracket 36 is attached to the leader 18. In this case, first, the individual suspension parts 43a for ground assembly of the divided body BR are identified, and the divided body BR is attached to the rear part of the leader 18 by a suspension operation using these parts and pin connection using the mounting pin 51. Next, the individual suspension parts 42a for ground assembly of the divided body BL are identified, and the divided body BL is connected to the divided body BR by a suspension operation using these parts and pin connection using the connecting pin 48. In this way, the stay bracket 36 is provided in a connected state on the rear side of the leader 18.

[0037] Next, the backstay 28 is lifted up, and while its middle part is held by the stay holding part 39 of the stay bracket 36, the tip stay member 28a is connected to the stay holder 25. In this way, a stable stay holding state in a substantially A-shape is created as shown in FIG. 2. After that, the gantry 21 is erected on the upper rotating body 13, and one end of the pendant rope 27, the other end of which is connected to the hoisting rope 26, is connected to the stay holder 25 as shown in FIG. 1. This brings the leader 18 and the backstays 28, 28 into a state in which they can be raised (a collapsed state). The various ropes 30, 32 passing behind the leader 18 are routed in the same manner as in the past.

[0038] Next, in cooperation with the auxiliary lifting of the crane, the leader 18 is raised vertically by the hoisting rope 26, and the backstays 28, 28 are raised together, and the stay cylinders 29, 29 are attached to the stay mounting parts 24, 24. In this case, the load of the backstays 28, 28 acts on the stay bracket 36 during the raising operation, but this load is removed as the hoisting angle of the leader 18 increases. Then, after the backstays 28, 28 are separated from the stay bracket 36, the load is released and finally the leader 18 is suspended from the back of the leader 18 only through the two mounting pins 51. In this way, as shown in FIG. 10, a three-point support is established between the leader 18 erected on the base machine 14 and the backstays 28, 28.

[0039] The removal work of the stay bracket 36 will be described below with reference to Figures 6 to 9. Here, since the handling of the suspending ropes 44 and the like and the release of the connecting part 40 are performed at a height, a foothold for the work is secured by arranging, for example, an aerial work vehicle (not shown) equipped with a liftable work platform.

[0040] First, as shown in Figures 6 and 7, among the multiple suspenders 41, 42, and 43, one-side detachable individual suspender 42b for suspending one of the divided bodies BL that does not have a leader attachment part 37 is specified, and one of the divided bodies BL is separated from the other divided body BR by a suspending operation using the one-side detachable individual suspender 42b and an operation to release the connected state. In this case, the center of gravity of the divided body BL, which serves as the suspending point, is located in the middle in the longitudinal direction, so that crane work and high-altitude work can be performed at a position away from the leader 18.

[0041] The connection part 40 is released by pulling out vertically upwards each of the two connection pins 48 inserted through the connection overlap part 47. In this operation, when tension is applied to the hanging rope 44, the slight inclination of the divided bodies BL is eliminated and the force restraining the connection pins 48 in the overlapping connection overlap parts 47 becomes smaller, so that the friction with the pin holes can be reduced and the connection pins 48 can be pulled out.

[0042] After removing the divided body BL, the scaffolding (work platform) is moved to the opposite side of the leader 18, and as shown in Figures 8 and 9, the other-side individual suspending part 43b for suspending the other divided body BR is identified from among the multiple suspending parts 41, 43, and the other divided body BR is removed from the back part of the leader 18 by a suspending operation using the other-side individual suspending part 43b for suspending. In this case, the center of gravity of the divided body BR, which serves as the suspension point, is located slightly toward the leader mounting part 37 side from the center in the longitudinal direction due to the presence of the leader mounting part 37, but this is not enough to hinder crane work or work at height.

[0043] The leader attachment section 37 is released by horizontally pulling out each of the two attachment pins 51 inserted through the attachment overlap section 50. In this operation, as in the previous operation, when tension is applied to the hanging rope 44, the slight inclination of the cantilevered divided body BR is eliminated, and the force that restrains the attachment pin 51 in the attachment overlap section 50 that overlaps in the leader width direction becomes smaller, so that the attachment pin 51 can be pulled out while suppressing friction with the pin hole.

[0044] After removing the divided body BR, the main hoisting rope 30 is attached to the auger attached to the front of the leader 18. In this way, the completed pile driver 11 obtains the necessary power from the power unit 17, for example, pressure oil to operate the main hoisting winch, and is ready to perform pile driving functions through various operations including raising and lowering the auger. When the pile driver 11 is transported from the site after construction is completed, the stay bracket 36 is attached to the leader 18 in the reverse order to that described above, and is used to hold the backstays 28, 28 when the leader 18 is lowered.

[0045] In this way, according to the pile driver 11 of the present invention, the stay bracket 36 that can be attached to the back of the leader 18 has the connecting part 40 for dividing it into two parts depending on whether the leader attachment part 37 is attached or not, so the leader attachment part 37 does not become a weak part against bending load, and the support function of the back stay 28 can be performed in a desirable manner. Moreover, since the connecting part 40 is provided in the middle area C2 including the leader attachment part 37 among the areas C1, C2, C3 that are equally divided into three longitudinal parts of the bar 38, by using the hanging parts 42, 43 according to the center of gravity of each of the divided bodies BL, BR, it becomes possible to perform the hanging operation without interference with the various ropes 30, 32 that pass through the back of the leader 18, and the work of attaching and detaching the stay bracket 36 can be performed safely one by one in order.

[0046] In addition, the individual hanging parts 42, 43 for hanging the split bodies BL, BR individually consist of individual hanging parts 42a, 43a for ground assembly and individual hanging parts 42b, 43b for removal and installation, which are arranged with their hanging directions perpendicular to each other, so that the removal and installation work of the stay bracket 36 can be performed safely whether the leader 18 is in a laid-down or upright position.

[0047] Furthermore, since the connecting portion 40 is provided with a connecting overlapping portion 47 consisting of a portion of each divided body BL, BR, and a connecting pin 48 disposed penetrating the connecting overlapping portion 47, a simple pin-type connecting structure suitable for work sites requiring speed can be obtained, and the stay bracket 36 can be smoothly connected and disconnected. In particular, since the connecting pin 48 is disposed in a direction parallel to the leader 18, the connecting overlapping portion 47 that overlaps above and below can be utilized when the leader 18 is in an upright position, so that the pin holes can be easily made coaxial during the hanging operation by inching, and the operation of inserting and removing the connecting pin 48 is easy and safe.

[0048] In addition, the leader mounting portion 37 is provided with a pin-type connection structure in which the mounting pin 51 is arranged in a horizontally orthogonal direction to the leader 18, and a mounting base 49 fixed to the back of the leader 18, and the bar 38 is supported by surface contact with the seat surface 49a provided on the mounting base 49, so that it is possible to reduce the load on the mounting pin 51 when supporting the weight of the backstay 28, and it is possible to achieve a reduction in the size and weight of the mounting pin 51, and thus a reduction in the size of the leader mounting portion 37 as a pin-type connection structure. In particular, the pin hole can be aligned by a simple hanging operation of simply placing the bar 38 on the seat surface 49a, which contributes to safety and work efficiency when installing the stay bracket 36.

[0049] The present invention is not limited to the above-mentioned embodiment, and the stay bracket can be formed using a beam material other than H-beam that is light and has excellent strength. The division position can be set in the middle area in the longitudinal direction, taking into consideration the movement of the center of gravity, and can be changed within a range that does not interfere with the work of hanging the divided bodies. Furthermore, the division bodies can be connected to each other and can be attached and detached to the leader using connecting means other than pins, such as bolts and nuts. [Explanation of symbols]

[0050] 11...pile driver, 12...lower running body, 13...upper rotating body, 14...base machine, 15...winch mounting section, 16...operator cab, 17...power section, 18...leader, 18a...leader base member, 18b...leader member, 19...front jack, 20...leader bracket, 21...gantry, 22...counterweight, 23...rear jack, 24...stay mounting section, 25...stay holder, 26...hoisting rope, 27...pendant rope, 28...back stay, 28a...tip stay member, 28b...intermediate stay member, 29...stay cylinder, 30...main hoisting rope, 31...main hoisting guide sheave, 32...auxiliary hoisting rope, 33...main hoisting guide sheave, 34...auxiliary hoisting rope, 35...main hoisting guide sheave, 36...main hoisting guide sheave, 37...main hoisting guide sheave, 38...main hoisting guide sheave, 39...main hoisting guide sheave, 40...main hoisting guide sheave, 41...main hoisting guide sheave, 42...main hoisting guide sheave, 43...main hoisting guide sheave, 44...main hoisting guide sheave, 45...main hoisting guide sheave, 46...main hoisting guide sheave, 47...main hoisting guide sheave, 48...main hoisting guide sheave, 49...main hoisting guide sheave, 50...main hoisting guide sheave, 51...main hoisting guide sheave, 52...main hoisting guide sheave, 53...main hoisting guide sheave, 54...main 3...auxiliary guide sheave, 34...intermediate guide sheave, 35...top sheave, 36...stay bracket, 37...leader mounting portion, 38...bar, 38a...reinforcing plate, 38b...mounting surface, 39...stay holding portion, 40...connecting portion, 41...overall hanging portion, 42, 43...individual hanging portion, 42a, 43a...individual hanging portion for ground assembly, 42b, 43b...individual hanging portion for removal and installation, 44...hanging rope, 45...bracket, 46...safety rope, 47...connecting overlap portion, 47a, 47b...bifurcated portion, 48...connecting pin, 49...mounting base, 49a...seat, 50...mounting overlap portion, 50a...mounting arm, 50b...bifurcated portion, 51...mounting pin, 52...support stand

Claims

1. A pile driver including a leader that can be raised and lowered at the front of a base machine and a pair of left and right backstays that support the leader from the rear, the leader and the backstays being assembled on the ground in front of the base machine and then being raised from a downed state to an upright position, A removable stay bracket is provided on the rear portion of the leader to hold the pair of left and right backstays in the collapsed state, The stay bracket has a bar with a leader attachment portion in the middle in the longitudinal direction, stay holding portions provided at both ends of the bar, and a connecting portion provided in an area including the leader attachment portion among three areas obtained by dividing the bar into three equal parts in the longitudinal direction, the connecting portion connecting the stay bracket into two divided bodies separably to each other depending on the presence or absence of the leader attachment portion, A pile driver characterized in that the bar is provided with a plurality of hanging portions corresponding to the center of gravity that changes when the stay bracket is in a connected state or a released state.

2. The plurality of suspending portions include an overall suspending portion for suspending the stay bracket in a connected state and an individual suspending portion for suspending the divided body alone, 2. The pile driver according to claim 1, wherein the individual suspending parts are comprised of an individual suspending part for ground assembly and an individual suspending part for detachment, the suspending directions of which are perpendicular to each other.

3. The pile driver described in claim 1 or 2, characterized in that the connecting portion comprises a connecting overlapping portion formed by overlapping parts of the two divided bodies, and a connecting pin that passes through the connecting overlapping portion and is arranged in a direction parallel to the leader.

4. The leader mounting portion includes a mounting base portion fixed to the rear surface of the leader, a mounting overlap portion formed by inserting a pair of mounting arms provided on the mounting base into a pair of bifurcated portions provided on the bar, and a mounting pin that passes through the mounting overlap portion and is arranged in a horizontal direction perpendicular to the leader, 4. The pile driver according to claim 1, wherein the mounting base is provided with a seat for supporting the bar in a surface-contact state.

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