Outrigger device

Abstract

To provide an outrigger device which can be configured in a limited space and set to an overhang width according to the usage condition of a construction machine.SOLUTION: Outrigger boxes 34 having rotation shafts 35 of outrigger arms 32 provided on both sides in a machine body width direction are fixed to a lower surface of a rear end of a machine body frame 25 of an upper revolving body. Outrigger jacks 19R, 19R can be set and held at three positions, namely, a tension width reduction position (MID) where central axes are arranged in alignment with a width of the upper revolving body at an inside position of a revolving trajectory line L1, a tension width expansion position (MAX) where the central axes are arranged apart from each other maximally in the machine body width direction at an outside position of the revolving trajectory line L1, and a retracted position (MIN) where the central axes are arranged within the width of the upper revolving body at the outside position of the revolving trajectory line L1, in order from the front side to the rear side in a longitudinal direction of the machine body, by moving arcuately on a rotation trajectory line L2. Outrigger holding means consists of a pin coupling structure capable of selectively holding the outrigger jacks in one of the three positions.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an outrigger device, and more particularly to an outrigger device provided on a rotating body of a construction machine. [Background technology]

[0002] Construction machinery such as cranes, earth drills, and pile drivers generally comprises a crawler-equipped travelling body, a rotating body with a cab, a work device attached to the front of the rotating body, and a counterweight attached to the rear of the rotating body. Among these various types of construction machinery, pile drivers are equipped with outrigger devices with extendable jack cylinders, which, in addition to being used to increase stability by touching the ground, can also change direction in narrow spaces by lifting the crawlers off the ground (see, for example, Patent Document 1), and can further raise the machine body with the crawlers detached to accommodate the bed of a transport trailer (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-188564 [Patent Document 2] Japanese Patent Publication No. 2018-2043 Summary of the Invention [Problem to be solved by the invention]

[0004] Because the outrigger devices described above are unnecessary when traveling or swinging, it is desirable to minimize their protrusion from the swinging body and to configure them compactly, particularly when using construction machinery in narrow spaces. On the other hand, in recent years, there have been many factors that have led to an increase in the weight of the machine, such as an increase in the power of work equipment, and if the requirement is imposed that the crawlers must be removed from the machine during transportation, a wide protrusion width corresponding to the width of the transport trailer bed is required, making it difficult to configure the outrigger devices compactly.

[0005] Therefore, an object of the present invention is to provide an outrigger device that can be constructed in a limited space and can be set to an extension width that suits the usage state of the construction machine. [Means for solving the problem]

[0006] In order to achieve the above object, the outrigger device of the present invention comprises an outrigger box in the width direction of the machine body, which is provided at the rear of an upper rotating body that is rotatably mounted on a lower running body via a slewing bearing, and on which a counterweight is detachably placed, a pair of outrigger arms that are provided on both sides of the outrigger box so as to be rotatable about a vertical rotation axis, outrigger jacks each comprising a jack cylinder and a ground plate provided on each of the pair of outrigger arms, and outrigger holding means for holding the outrigger jack in a set position, and the positional relationship is such that the rotation locus line described by the rear end of the counterweight moving in an arc when the upper rotating body rotates and the rotation locus line described by the central axis of the outrigger jack moving in an arc when the outrigger arms rotate intersect in a plan view. In the outrigger device arranged as described above, the outrigger box is fixed to the underside of the rear end of the machine frame to which one of the inner and outer rings of the slewing bearing is attached, and the pair of outrigger jacks can be set to three positions, in order from the front to the rear in the longitudinal direction of the machine body, by moving in an arc on the rotation trajectory line: a tensioned width reduced position where the center axes are positioned inside the slewing trajectory line and aligned to the width of the upper slewing body; a tensioned width increased position where the center axes are positioned outside the slewing trajectory line and spaced apart at the maximum in the machine body width direction; and a stored position where the center axes are positioned outside the slewing trajectory line and contained within the width of the upper slewing body, and the outrigger holding means has a pin connection structure that can selectively hold the outrigger jack in any of the three positions.

[0007] The pin connection structure is also characterized by having a pin hole that passes through the overlapping portion of the outrigger arm and the outrigger box, a retaining pin that is inserted and removed from the pin hole, and a pin insertion and removal work space formed by separating the underside of the counterweight above the pin hole. [Effects of the Invention]

[0008] According to the outrigger device of the present invention, an outrigger box equipped with the rotation axis of the outrigger arm is provided on the underside of the rear end of the machine frame, so it is possible to increase the forward rotation range of the outrigger arm from the position where it is extended in the width direction of the machine.Even in construction machinery with the machine width and turning radius maximized, a compact outrigger device with the length of the rotating arm kept to the minimum necessary can be installed, and the outrigger device can be set to a reduced tension position that does not interfere with turning or traveling, an expanded tension position that is suitable for the purpose of disassembling and transporting the machine, and a storage position.

[0009] Furthermore, because a pin connection structure is used as the outrigger holding means, the outrigger device can be constructed at low cost and light weight. Moreover, because the outrigger jack can be held in the desired position by simply inserting and removing the holding pin, an outrigger device that meets the needs of on-site work where speed is required is achieved. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view of a pile driver equipped with an outrigger device showing one embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 10 is a plan view showing the same transport posture with the leader laid down. [Figure 5] FIG. 10 is a side view of the main part showing the outrigger device in an attached state. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 10 is a diagram showing the state in which the outrigger jacks are extended to lift the crawler off the ground. [Figure 9] This is a diagram showing the state in which the bed of a transport trailer has been received directly below the aircraft body. [Figure 10] FIG. 10 is a diagram showing the state in which the machine body is loaded onto the bed of a transport trailer. DETAILED DESCRIPTION OF THE INVENTION

[0011] Figures 1 to 10 show the application of the present invention to a pile driver, which is an example of construction machinery. As shown in Figures 1 to 4, the pile driver 11 is equipped with a base machine (machine body) 15, which is made up of a lower traveling body 12 equipped with left and right crawler devices 12a and an upper rotating body 14 rotatably mounted on the lower traveling body 12 via a rotating bearing 13, a leader 16 erected at the front of the upper rotating body 14, and a hoisting cylinder 17 that supports the leader 16 from behind.

[0012] A leader support 18 that supports the leader 16 so that it can be raised or lowered is provided at the front of the upper rotating body 14. A pair of left and right front jacks 19F, 19F for stabilization and with adjustable tension width are also provided at the front end of the upper rotating body 14. Furthermore, an outrigger device equipped with a pair of left and right outrigger jacks 19R, 19R for stabilization and with adjustable tension width is provided at the rear end of the upper rotating body 14, and a counterweight 20 for balancing the pile driver 11 is mounted on the top surface of the outrigger device body.

[0013] The leader 16 is formed by dividing it into a rotatable basic leader 21 pivotally supported on the leader support 18, an upper leader 22 connected to the top of the basic leader 21, and a lower leader 23 connected to the bottom of the basic leader 21. Furthermore, the upper leader 22 is formed by dividing it into a plurality of leader members, and a top sheave 24 is attached to the upper end. In addition, a rotary drive device (not shown) is attached to the front of the leader 16 so that it can be raised and lowered.

[0014] The flange members at the upper and lower ends of each leader member are detachably connected to each other with bolts and nuts. When transporting the pile driver 11, the leader 16 thus formed is transported separately from the machine body by removing the upper leader 22 according to the transport conditions. In this case, heavy objects such as the rotary drive device and counterweight 20 are removed from the machine body as necessary, and the basic leader 21 is tilted backward independently of the lower leader 23 to assume a transport position, as shown in Figures 4 and 8.

[0015] The upper rotating body 14 has a machine frame that is made up of a rectangular box-shaped main frame 25, on the underside of which the swing bearing 13 is attached, and floor frames 26 (the opposite side is not shown) that are framed on both widthwise sides of the main frame 25 and are joined together. An operator's cab 27, in which the operator sits, is installed at the front of the right floor frame. An equipment storage house 28 that stores hydraulic equipment is installed at the rear of the right floor frame (Figure 4). Meanwhile, an engine storage house 29 that stores the engine power unit and associated equipment such as an exhaust gas purification system is installed on the left floor frame 26.

[0016] Each house 28, 29 is formed in a box shape by a frame structure integrated with a rectangular (C-shaped cross section) floor frame 26 and a sheet metal structure that provides the exterior, and is equipped with a base frame that defines the storage space and multiple cover members including doors that are attached to the base frame. The houses 28, 29 usually have their outer surfaces with doors aligned with the outer surfaces of the floor frames 26, corresponding to the width (transport width) of the upper rotating body 14.

[0017] The counterweight 20 is made up of multiple flat, wide blocks stacked high, with both widthwise end sides large enough to correspond to the width of the upper rotating body 14, but significantly smaller in the front-to-rear direction than in the widthwise direction, and both sides of the rear end face are chamfered symmetrically in the widthwise direction. The counterweight 20 thus formed is mounted by sandwiching the rear end of the main frame 25 between the outrigger unit body and the counterweight 20, and the counterweight 20 is fastened together as a unit with long bolts 30 (Figure 7).

[0018] 5 and 9, the slewing bearing 13 disposed between the lower traveling body 12 and the upper rotating body 14 is formed by assembling an inner wheel side slewing bearing case 13a fixed to the central upper surface of the track frame 12b of the lower traveling body 12 and an outer wheel side slewing bearing case 13b fixed to the central lower surface of the main frame 25 so as to be capable of relative rotation. An internal gear is formed on the inner periphery of the inner wheel side case 13a, and a gear of a slewing drive motor (not shown) mounted on the upper rotating body 14 is meshed with the internal gear, and by rotating the slewing drive motor, the upper rotating body 14 is rotated horizontally relative to the lower traveling body 12.

[0019] When rotating the upper rotating body 14, particular attention must be paid to the front rotation area FS where construction materials (e.g., steel pipe piles) are present, and the rear rotation area RS which is difficult to see from the driver's seat, as shown in Figure 4.

[0020] Therefore, to ensure safe operation, a turning circle (not shown) is set for the front turning region FS, with the turning radius being the horizontal distance between the outer circumferential surface of the construction member and the turning center (turning axis) of the upper turning body 14. When turning, an anti-vibration device (not shown) attached to the front of the leader 16 is opened in a predetermined procedure to position it inside the turning circle. On the other hand, for the rear turning region RS, a turning trajectory line L1 is set, in which the rear end of the counterweight 20, i.e., the part farthest from the turning center, moves in an arc during turning, and the extension width of the outrigger device (outrigger jack 19R) is set to match the width of the upper turning body 14, so that both the left and right outrigger jacks 19R, 19R are positioned inside the turning trajectory line L1. The extension width adjustment means will be described in detail later, but this reduces unnecessary protrusion from the upper turning body 14, allowing for safe turning and traveling.

[0021] The front jack 19F and outrigger jack 19R are each configured to have three different projection widths. Each jack 19F, 19R is detachably attached to the tip of the front and rear outrigger arms 31, 32, which can rotate horizontally, and is composed of a jack cylinder (hydraulic cylinder) 19a with a predetermined extension length and a ground plate 19b attached to the bottom end of the jack cylinder 19a. Because each jack 19F, 19R is heavy, when handling it as a component, for example, a hanging part 19c attached to the top end of the jack cylinder 19a is used.

[0022] The extension width of the outrigger units can be set to three positions, in order from the front to the rear in the fore-and-aft direction of the machine body: a reduced tension width position (MID, imaginary line in FIG. 4) in which the central axes of the jacks 19F, 19R are aligned with the width of the upper rotating body 14; an increased tension width position (MAX, solid line in FIG. 4) in which they are spaced farthest apart in the width direction of the machine body; and a stored position (MIN, imaginary line in FIG. 4) in which they are contained within the width of the upper rotating body 14. Depending on the usage state of the pile driver 11, it is selectively set to the reduced tension width position (MID) during construction, the increased tension width position (MAX) when the crawler unit 12a is disassembled, or the stored position (MIN) during transportation.

[0023] Incidentally, in recent years, construction sites have become more diverse, and there are more opportunities to use pile drivers 11 in narrow spaces, so it is desirable to configure the outrigger devices as compact as possible. On the other hand, there is a trend toward increased machine weight due to the need for higher output and stricter exhaust gas regulations, and if the requirement is imposed that the crawler device 12a be detached from the machine body during transportation, even small models will require a wide overhang width that corresponds to the width of the transport trailer bed, making it difficult to configure the outrigger devices compactly.

[0024] In particular, the floor frame 26, which is integral with the main frame 25, is equipped with many devices, such as an exhaust gas purification system, in addition to the engine power unit, and therefore its external dimensions become large in the fore-and-aft direction. If a considerable amount of counterweight 20 were to occupy the space at the rear of the machine, which is now tight on space, it would become impossible to provide an outrigger device in a form appropriate for the actual use. For this reason, the rear end of the upper rotating body 14 is equipped with an outrigger device that can be configured in a limited space and has an overhang width that can be set according to the actual use.

[0025] As shown in Figures 5 to 7, the outrigger device 33 has an outrigger box 34 in the width direction of the machine body on which the counterweight 20 is removably placed, a pair of outrigger arms 32, 32 each rotatably mounted on both sides of the outrigger box 34 around a vertical rotation axis (rotation pin) 35, outrigger jacks 19R, 19R each mounted on the pair of outrigger arms, and outrigger holding means for holding the outrigger jacks at each projection width position (MIN, MID, MAX).

[0026] The height position of the outrigger unit 33 relative to the machine body is set low within a range that satisfies the required minimum ground clearance, as shown in Fig. 5 etc. Furthermore, the horizontal position of the outrigger unit 33 relative to the machine body is set so that a rotation locus line L2 is described by the central axis of the outrigger jack 19R moving in an arc when the outrigger arm 32 rotates, and as can be seen from the plan view in Fig. 6, the rotation locus line L1 and the rotation locus line L2 intersect at positions symmetrical with respect to the center line of the machine body in the width direction.

[0027] The outrigger box 34 is fixed to the underside of the rear end of the main frame 25 to lower the center of gravity of the entire device. It is formed into a closed box shape with upper and lower plates that correspond to the planar shape of the counterweight 20 and a vertical plate that connects the upper and lower plates. A roughly U-shaped arm connector consisting of the upper and lower plates and the vertical plate is provided on both sides, and the base end of the outrigger arm 32 inserted into the arm connector is supported by a pivot 35. A pair of lugs (for hanging) 36, 36 used during assembly are provided on the top surface of the outrigger box 34, allowing bolts to be securely fastened to the underside of the main frame 25. A pair of lugs (for fastening) 37, 37 used during transportation are provided on the front of the outrigger box 34, allowing it to be fixed to the bed of a transport trailer with a jig or the like.

[0028] The outrigger arm 32 has a cylindrical shape with a rectangular cross section that fits between the upper and lower plates of the outrigger box 34 at its arm connecting portion, has an axial hole for the pivot shaft 35 at its base end, and has a pair of upper and lower fixing pins 38, 38 at its tip end for attaching and detaching the outrigger jack 19R. The length of the arm of the outrigger arm 32 defines the pivot radius of the outrigger jack 19R, i.e., the center-to-center distance between the central axis of the outrigger jack 19R and the pivot shaft 35 of the outrigger arm 32. This defined pivot radius is set to be approximately the same as the maximum value of the fore-aft dimension of the counterweight 20, in other words, the fore-aft dimension of the projection line of the counterweight 20 projected in the width direction.

[0029] As shown in Figure 6, the outrigger jack 19R, which moves in an arc on the rotation trajectory line L2, rotates from the front side (upper side of Figure 6), where a portion of the outrigger arm 32 is positioned in the lower region of the floor frame 26, out of that lower region and toward the rear side (lower side of Figure 6), without moving too far away from structures such as the counterweight 20, which form both side wall portions of the rear end of the upper rotating body 14, the floor frame 26, and the houses 28 and 29, making small turns at a predetermined angle along these wall surfaces.

[0030] In this way, the pair of outrigger jacks 19R, 19R move in an arc on the rotation trajectory line L2, and are set to three positions, in order from the front to the rear in the fore-and-aft direction of the machine body: a tension width reduction position (MID) where the central axes are positioned inside the rotation trajectory line L1 to match the width of the upper rotating body 14; a tension width expansion position (MAX) where they are positioned outside the rotation trajectory line L1 and are spaced apart the maximum in the width direction of the machine body; and a storage position (MIN) where the central axes are positioned outside the rotation trajectory line L1 within the width of the upper rotating body 14, specifically, so that they are the same distance (same span) as the rotating axes.

[0031] The outrigger holding means is a pin connection structure that can selectively hold the outrigger jack 19R at any one of the overhang width positions. As shown in Figures 2, 3, 6, etc., this pin connection structure includes pin holes 32a, 34a that pass through the overlapping portions of the upper plate of the outrigger arm 32 and the upper plate of the outrigger box 34, a holding pin 39 that is inserted into and removed from the pin holes, and a pin insertion / removal work space WS that is formed by spacing the underside of the counterweight 20 upward from the pin holes 32a, 34a.

[0032] One pin hole 32a, 34a is provided on each of the pair of outrigger arms 32, 32, and three pin holes 32a, 34a are provided on each side (the joint between the arms) of the outrigger box 34, corresponding to the positions of each overhang width. The three pin holes 34a on the outrigger box 34 side are each provided concentrically with the rotation shaft 35 and spaced apart from each other in the circumferential direction. Two retaining pins 39 are provided, one on each side, that can be selectively inserted and removed into the three pin holes 34a on each side.

[0033] The pin insertion / removal work space WS is a gap provided between the top and bottom of both sides of the counterweight 20 and the arm connector, and is formed by cutting out the lower corners of the counterweight 20 in a stepped shape, with its height kept low enough to allow a hand to reach in and insert / remove the retaining pin 39. This makes it possible to set the desired overhang width without removing the counterweight 20.

[0034] When the pile driver 11 equipped with such an outrigger device 33 is used on-site, for example, to bury steel pipe piles, the front jack 19F and the outrigger jack 19R are held in their respective reduced extension width positions (MID), and the jack cylinders 19a are extended to assume a pile driving position with all jacks in contact with the ground (Figure 1).

[0035] Here, the steel pipe pile has its upper end connected to the drive shaft of the rotary drive device, and its lower end held by the vibration control device. The connected steel pipe pile is rotated by the driving force from the rotary drive device, and is driven into the ground by lowering the rotary drive device while still rotating. During this pile driving operation, the leader 16 is subjected to a combined load of axial (vertical) tension and torsion due to the driving force of the rotating pile, and part of this load is transmitted through the main frame 25 and acts on each of the outrigger jacks 19F, 19R.

[0036] When extending a steel pipe pile, the buried steel pipe pile is separated from the drive shaft, the anti-vibration device is opened, and the jack cylinder 19a is retracted, allowing the upper rotating body 14 to rotate in place. At this time, with the anti-vibration device open and retracted to a position inside the rotation circle, the upper rotating body 14 can rotate without interfering with the buried steel pipe pile. Furthermore, at the rear of the machine, the outrigger jack 19R is held inside the rotation trajectory line L1, allowing for rotation without interfering with surrounding structures. In this way, the prepared steel pipe pile to be extended is connected at its upper end to the drive shaft in the side area of the machine, and is carried to the construction position (pile core) by rotating in the opposite direction.

[0037] On the other hand, when transporting the pile driver 11 from the site, the upper leader 22 is removed, and on the machine body side, heavy objects such as the rotary drive unit and counterweight 20 are removed, depending on the transport restriction conditions, and the basic leader 21 is placed in a transport posture with the rearward tilted position, as shown in Figure 8. Here, when a condition is imposed that requires the crawler unit 12a to be removed from the machine body, the retaining pin 39 is replaced, and the front jack 19F and outrigger jack 19R are each changed from the reduced tension width position (MID) to the increased tension width position (MAX), maintaining a wide extension width corresponding to the bed width of the transport trailer.

[0038] Next, after placing the pedestals 40 directly below the ground plate 19b (at four locations), the jack cylinders 19a are extended to raise the crawler device 12a above the ground, and the crawler device 12a is disassembled according to a predetermined procedure. That is, the track frame 12b and the left and right crawler devices 12a are separated from each other in the lower traveling body 12. Thereafter, by extending the jack cylinders 19a to their maximum, a large space is created below the machine body, as shown in FIG. 9, making it possible to accommodate the bed 41 of a transport trailer.

[0039] After loading onto the loading platform 41, the retaining pins 39 are replaced, and the front jack 19F and outrigger jack 19R are each changed from their extended width position (MAX) to their retracted position (MIN) as shown in Figure 10, and are held within the loading platform width (transport width) that allows for safe transportation. At this time, depending on the amount of elevation of the machine body, measures may be taken, such as removing both of the pair of upper and lower fixing pins 38, 38 at the tip of the outrigger arm 32 to remove the outrigger jack 19R, or removing only the lower fixing pins 38, 38 to tilt the outrigger jack 19R (not shown), to prevent the outrigger unit 33 from coming into contact with the loading platform 41.

[0040] In this way, according to the outrigger device 33 of the present invention, the outrigger box 34 equipped with the rotation axis 35 of the outrigger arm 32 is provided on the underside of the rear end of the machine body frame (main frame 25), so it is possible to increase the forward rotation range of the outrigger arm 32 from the position where it is extended in the machine body width direction.Even in construction machinery with machine body width and turning radius maximized, a compact outrigger device 33 with the length of the rotating arm kept to the minimum necessary can be installed and set to a tensioned width reduced position (MID) that does not interfere with turning or traveling, a tensioned width expanded position (MAX) that is suitable for the purpose of disassembling and transporting the machine, and a storage position (MIN).

[0041] Furthermore, because a pin connection structure is used as the outrigger holding means, it is possible to construct a lightweight and inexpensive outrigger device 33. Moreover, because the outrigger jack 19R can be held in the desired position by the simple operation of inserting and removing the holding pin 39, it is possible to achieve an outrigger device 33 that meets the needs of the field where speed is required.

[0042] Furthermore, the pin connection structure is provided with a pin insertion / removal work space WS formed by separating the underside of the counterweight 20 upward from the pin holes 32a, 34a, so a work space can be secured in which the retaining pin 39 can be inserted and removed, regardless of whether the counterweight 20 is present. This makes it possible to manually perform a series of rotation operations of the outrigger arm 32 quickly and accurately while stably supporting the heavy outrigger jack 19R in a cantilevered manner, in accordance with various modes of transporting construction machinery.

[0043] The present invention is not limited to the above-described embodiments. The outrigger box, outrigger arm, the shape of their connecting parts, the location of the pivot shaft, and the holding means can be modified as appropriate for the construction machine to which the outrigger device is to be deployed and its specifications. Furthermore, by placing a jig such as a spacer member (pin type) between the jack and the outrigger arm when moving the outrigger device to the site, a wider projection width can be achieved, contributing to a series of safe operations from disassembling the crawler device to loading it onto the transport platform. Furthermore, while a pile driver has been used as an example of construction machine, the present invention is not limited to this, and the outrigger device can be applied to various construction machines equipped with a rotating body. In this case, the outrigger device, which can be deployed in a space-saving manner, allows for greater design freedom, including the location of equipment mounted on the rotating body, and allows for smooth model changes and new model development. [Explanation of symbols]

[0044] 11...pile driver, 12...lower running body, 12a...crawler device, 12b...track frame, 13...slewing bearing, 13a, 13b...slewing bearing case, 14...upper slewing body, 15...base machine, 16...leader, 17...derailing cylinder, 18...leader support, 19F...front jack, 19R...outrigger jack, 19a...jack cylinder, 19b...ground plate, 19c...hanging part, 20...counterweight, 21...basic Leader, 22...upper leader, 23...lower leader, 24...top sheave, 25...main frame, 26...floor frame, 27...operator's cab, 28...equipment storage house, 29...engine storage house, 30...bolt, 31, 32...outrigger arm, 32a...pin hole, 33...outrigger device, 34...outrigger box, 34a...pin hole, 35...rotating shaft, 36, 37...ear, 38...fixing pin, 39...retaining pin, 40...base, 41...cargo bed

Claims

1. The upper rotating body is rotatably mounted on the lower traveling body via a slewing bearing, and the upper rotating body is provided at the rear of the upper rotating body. The outrigger box is disposed in the width direction of the machine body and has a counterweight detachably mounted thereon; a pair of outrigger arms are provided on both sides of the outrigger box so as to be rotatable about a vertical rotation axis; outrigger jacks are provided on the pair of outrigger arms, each of which comprises a jack cylinder and a ground plate; and outrigger holding means for holding the outrigger jacks in a set position. In an outrigger device arranged so that a rotation locus line described by the rear end of the counterweight moving in an arc when the upper rotating body rotates and a rotation locus line described by the central axis of the outrigger jack moving in an arc when the outrigger arm rotates intersect in a plan view, The outrigger box is fixed to a lower surface of the rear end portion of the aircraft frame to which one of the inner and outer rings of the slewing bearing is attached, The pair of outrigger jacks can be set to three positions, in order from the front to the rear in the longitudinal direction of the machine body, by moving in an arc on the rotation trajectory line: a tension width reduction position in which the central axes are positioned inside the rotation trajectory line to match the width of the upper rotating body; a tension width expansion position in which the central axes are positioned outside the rotation trajectory line to be separated by the maximum in the machine body width direction; and a storage position in which the central axes are positioned outside the rotation trajectory line to be contained within the width of the upper rotating body, The outrigger device is characterized in that the outrigger holding means is made of a pin connection structure that can selectively hold the outrigger jack in any of the three positions.

2. The outrigger device according to claim 1, characterized in that the pin connection structure includes a pin hole that passes through the overlapping portion of the outrigger arm and the outrigger box, a retaining pin that is inserted and removed from the pin hole, and a pin insertion and removal work space formed by separating the underside of the counterweight above the pin hole.

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