JP2019085227A - Construction machine - Google Patents

Abstract

To provide a construction machine capable of easily performing the work for extracting/inserting a connection pin of a standing gantry without decreasing the safety.SOLUTION: The construction machine includes a lower connection pin 38 inserted into lower pin insertion holes 35a and 37c that are provided in an overlapped part of a lower rear leg 35 and an intermediate connection member 37 of a gantry and an upper connection pin 39 inserted into upper pin insertion holes 36c and 37b provided in an overlapped part of an upper rear leg 36 and the intermediate connection member. A foothold 41 where a worker performing the work for inserting the upper connection pin moves is provided on the lower rear leg. A handrail part 45 to which a hook of a safety belt mounted on a body of the worker is attachable/detachable is provided in the intermediate connection member.SELECTED DRAWING: Figure 8

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a construction machine, and more particularly to a construction machine provided with a gantry which can be undulated on an upper swing body.

  In construction machines such as cranes and pile drivers, a wire unwound from a winch provided at the rear of the upper structure is provided to be able to be undulated at the front of the upper structure via a gantry provided at the rear of the upper structure. Connection to the boom and the leader. As the gantry, a combination of a front leg rotatably mounted on the upper swing body and a rear leg consisting of a plurality of leg members telescopically formed between the upper end of the front leg and the upper swing body, The gantry is in the upright state (working state) when the rear leg is extended, and the gantry is in the collapsed state (stored state) when the rear leg is contracted, and a pin provided on the rear leg There is known a telescopic structure of a gantry which can be fixed in an arbitrary state by inserting a connecting pin into the insertion hole (see, for example, Patent Document 1).

JP 2000-169086 A

  In recent years, with a large-sized pile driver, the gantry mounted on the upper revolving structure is also enlarged with the lengthening of the leader, and in the state where the gantry is erected, the position of the pin insertion hole for inserting and removing the connection pin is It is installed at a considerable height from the ground. For this reason, in order to secure a foothold of a worker, it is necessary to use a relatively high lift working vehicle, and the operation cost for inserting and removing the connecting pin increases. In addition, since the handling of the aerial platform vehicle is limited to qualified persons, there is a problem that the response in the case of an emergency is delayed.

  Therefore, an object of the present invention is to provide a construction machine capable of easily performing an operation of inserting and removing a connection pin of a gantry which has been erected without reducing safety.

  In order to achieve the above object, the construction machine of the present invention comprises a pair of left and right front legs rotatably mounted at the lower end on the front side of the upper structure, the upper end of the front leg and the rear side of the upper structure. A pair of left and right rear legs provided between the lower legs, the lower legs being rotatably mounted on the upper swing body, and the upper ends being rotatable to the upper end of the front legs And the upper end of the lower rear leg and the lower end of the upper rear leg are telescopically connected by sliding in the longitudinal direction with each other via an intermediate connection member, By raising the upper end, the rear leg is extended and stands up, and by lowering the upper end of the front leg, the gantry is erected in a construction machine equipped with a gantry in which the rear leg is contracted to fall down. Lower leg and the middle A lower connecting pin inserted into a lower pin inserting hole provided in the overlapping portion with the connecting member; and an upper connecting pin inserted into an upper pin inserting hole provided in the overlapping portion between the upper rear leg and the intermediate connecting member; The lower rear leg is provided with a footing which is moved by a worker who carries out the insertion work of the upper connection pin, and the handrail portion to which the hook of the safety belt attached to the body of the worker can be attached or detached. It is characterized by having provided.

  Further, the scaffold is characterized in that it is a work bench constructed on the upper end portion of the left and right pair of lower rear legs, and a plurality of steps provided on the side surfaces of the lower rear legs and vertically separated. Further, the handrail portion is attached to a mounting arm whose upper end is provided at an upper end portion of the intermediate connection member, and a vertical bar member disposed in a state along the intermediate connection member, and an upper end portion of the rear leg And an engaging arm slidably holding a lower portion of the vertical bar member.

  In addition, the handrail portion is characterized by including a horizontal bar member mounted on the upper end portion of the left and right pair of intermediate connection members, and the upper connection pin and the lower connection pin are respectively provided on the work bench It is characterized in that a pin storage portion for storing is provided.

  According to the construction machine of the present invention, the lower rear leg of the gantry is provided with a scaffold movable by the worker who performs the insertion work of the upper connection pin, and the intermediate connection member is the hook of the safety belt attached to the worker's body. Since the handrail part which can be attached and removed is provided, the insertion work of the upper connection pin can be performed easily and safely without using a work at a high place.

  In addition, since the footing is a work bench constructed on the upper end of the pair of left and right lower rear legs, and a plurality of steps provided on the side surfaces of the lower rear legs and separated vertically, it is possible to It is possible to insert the upper connection pins into the upper pin insertion holes of the left and right two places simply by moving the work table laterally while making the compact along the rear leg of the gantry, and the insertion work of the upper connection pins It can be done more easily and quickly.

  Further, the vertical bar member constituting the handrail portion is formed to slide integrally with the intermediate connection member while holding the engaged state with the engagement arm provided at the upper end portion of the lower rear leg. The vertical bar members can be arranged along the intermediate connecting member without disturbing the back legs and the telescopic movement. In addition, since the lower end of the vertical bar member is engaged with the engagement arm when the gantry is erected, rattling of the vertical bar member can be suppressed, and the vertical bar member can be stabilized. While grabbing, you can raise and lower more safely along the rear legs.

  Furthermore, since the horizontal bar members constituting the handrail portion are bridged to the upper end portions of the left and right pair of intermediate connection members, the hooks of the safety band may be attached to the horizontal bar members to move safely on the work table. it can. In addition, it becomes possible to arrange the horizontal bar member at the height of the worker about the height, and not only can avoid the danger state that the worker may fall down, such as stepping on the rope of the safety belt, by any chance. When the worker slides the foot and falls, the falling distance can be shortened to reduce the impact load at the time of falling. Furthermore, it becomes possible to arrange the both ends of the horizontal bar member and the upper end of the vertical bar member in close proximity, and when the hook of the safety belt is changed between the horizontal bar member and the vertical bar member, no connection state Can be reduced.

  Also, since the pin storage portion for storing the upper connecting pin and the lower connecting pin is provided on the work bench, when connecting or lowering the gantry, prepare each connecting pin in the vicinity of the corresponding pin insertion hole in advance. This eliminates the need to lift and lower the gantry by holding heavy connecting pins.

It is a side view of a pile driving machine which shows one example of an embodiment of the present invention. It is also a plan view. It is a rear view similarly. It is a principal part rear view of a gantry similarly. It is a V-V cross-sectional view of FIG. It is VI-VI sectional drawing of FIG. It is a principal part enlarged side view when the back leg of the gantry is reduced similarly. It is a principal part enlarged side view when the back leg of a gantry is extended similarly.

  FIGS. 1 to 8 show an example of application of the construction machine of the present invention to a pile driver. The pile driver 11 has a swing bearing 13 at the upper part of a lower traveling body 12 provided with a crawler 12a. The upper swing body 14 is rotatably provided via the upper swing body 14, and a working device (not shown) for pile driving such as a leader is provided at the front of the upper swing body 14. In addition, on the left and right side surfaces of the crawler 12a, a folding type passenger steps 12b and 12b are respectively provided.

  On the floor frame 14a of the upper revolving superstructure 14, the driver's room 15 and the equipment room 16 are provided on the right side and the engine room 17 containing the engine and hydraulic pump on the left side. , A plurality of inspection doors 18 and ladders 19 are provided. Further, at the front of the engine compartment 17, a stair 20 for moving from the floor frame 14a to the top plate 17a of the engine compartment 17 is provided. Furthermore, an outrigger box 22 to which rear jacks (outrigger jacks) 21 and 21 are attached and a counterweight (not shown) placed on the outrigger box 22 are provided at the lower end of the rear end of the upper swing body 14 It is done. In addition, a gantry 23 is provided at the upper rear of the upper swing body 14.

  The gantry 23 is provided with a gantry sheave 26 for guiding a relief rope 25 fed from a relief winch 24 provided at the center rear of the upper swing body 14. The undulating rope 25 is wound around a pair of front and rear gantry sheave blocks 27, 28, and the other end of a pendant rope (not shown) whose one end is connected to the leader side is connected to the front gantry shire block 27 There is.

  Further, the gantry 23 has a pair of left and right front legs 30 and 30 rotatably mounted in the front and rear direction on a pair of left and right connecting arms 29 and 29 provided on the front part of the upper swing body 14, and the front legs 30 and 30. The pair of left and right rear legs 31 and 31 provided between the upper end of the upper revolving unit 14 and the rear of the upper revolving unit 14 are combined with each other to be erected on the rear of the upper revolving unit 14 in an undulating manner. In addition, a sheave support shaft 32 rotatably supporting the gantry sheave 26 is stretched over the gantry 23. Furthermore, a gantry relief cylinder 33 is provided between the lower part of each front leg 30 and the upper swing body 14 for raising and lowering the gantry 23 by hydraulic pressure.

  The rear leg 31 has a cylindrical lower rear leg 35 having a rectangular cross-sectional shape rotatably mounted at the upper ends of connecting arms 34 and 34 whose lower ends are respectively provided on the left and right of the rear part of the upper swing body 14, An upper rear leg 36 made of a long thick plate material rotatably attached to an upper end portion of the front leg 30, and a cylindrical intermediate in a rectangular cross section connecting the lower rear leg 35 and the upper rear leg 36 It is a telescopic telescopic structure provided with a connecting member 37. Thus, the gantry 23 extends the gantry relief cylinder 33 and raises the upper end of the front leg 30, whereby the rear leg 31 is extended and the gantry sheave 26 is positioned at a preset height (see FIG. 1, and retracts the gantry relief cylinder 33 and lowers the upper end of the front leg 30 to reduce the rear leg 31 so that the gantry sheave 26 is positioned rearward of the outrigger box 22 (FIG. It is set to be an imaginary line).

  Further, in a state in which the rear leg 31 is contracted, the lower connection pin 38 is provided in the lower pin insertion holes 35a, 36a, 37a provided in the overlapping portion of the lower rear leg 35, the upper rear leg 36 and the intermediate connection member 37. The upper connection pins 39 are respectively inserted into the upper pin insertion holes 36b and 37b provided in the overlapping portion between the rear leg 36 and the intermediate connection member 37, and the connection pins 38 and 39 are prevented by the beta pins 40 to prevent the rear legs 31 is fixed at the reduction position (FIG. 7). On the other hand, in the state where the rear leg 31 is extended, the lower connection pin 38 is provided in the lower pin insertion holes 35a and 37c provided in the overlapping portion of the lower rear leg 35 and the intermediate connection member 37, and the upper rear leg 36 and the intermediate connection member The upper connection pins 39 are respectively inserted into the upper pin insertion holes 36c and 37b provided in the joint portion with 37, and the connection pins 38 and 39 are prevented from coming off by the beta pins 40, whereby the rear leg 31 is fixed at the extended position. (Figure 8).

  The lower rear leg 35 is provided with a scaffold 41 for a worker to move the upper connecting pin 39 through. The scaffold 41 is an elevation step 42 for the operator to ascend and descend along the rear leg 31, and a work bench for moving laterally between the pair of left and right rear legs 31, 31 at a position above the elevation step 42. And 43.

  The raising and lowering step 42 has a three-stage configuration including a first raising and lowering step 42a, a second raising and lowering step 42b, and a third raising and lowering step 42c, and each raising and lowering step 42a, 42b, 42c obtained by bending a round bar member into a U shape in plan view. The first rear elevation step 42a, the second elevation step 42b, and the third elevation step 42c are vertically spaced from the middle portion of the lower rear leg 35 in the upward direction. In addition, the first raising and lowering step 42a and the third raising and lowering step 42c are provided on the front surface of the lower rear leg 35, and the second raising and lowering step 42b is provided on the outer surface of the lower rear leg 35. Are alternately arranged on the front and outer side surfaces of the lower rear leg 35.

  The work table 43 is a bracket provided respectively on a scaffolding plate 43a having a rectangular shape in a plan view rectangular shape and a U-shaped cross section in which the width direction of the upper revolving superstructure 14 is longitudinal, and upper end portions of a pair of left and right lower rear legs 35, 35 It is composed of a horizontal frame 43b having a U-shaped cross section, of which both ends are fastened by bolts 44 at 35b and 35b, and a pair of substantially triangular support plates 43c and 43c provided on the rear surface of the horizontal frame 43b. The scaffolding plate 43a is bridged over the upper end portions of the pair of left and right lower rear legs 35, 35 while being supported by the lateral frame 43b and the supporting plate 43c. Further, the scaffolding plate 43a is extended at both ends corresponding to the projecting position of the second lifting step 42b, and is subjected to anti-slip processing in which the peripheries of the plurality of round holes 43d provided on the upper surface are formed convex. ing.

  Further, box shaped pin storage portions 43e for storing the upper connection pins 39 and the lower connection pins 38 are provided at both ends of the scaffolding plate 43a, and the round holes 43f penetrating the pin storage portions 43e in the vertical direction. The respective connecting pins 38 and 39 are inserted respectively into the head of the connecting pins 38 and 39 so that the head of each connecting pin 38 and 39 is locked to the locking piece 43g provided on the upper surface of the pin storage portion 43e. It is supposed to be.

  The intermediate connection member 37 is provided with a handrail portion 45 to which a hook (not shown) of a safety belt attached to the body of the worker can be attached and detached. The handrail portion 45 is composed of an elevation handrail 46 for the operator to ascend and descend along the rear leg 31, and a work handrail 47 for performing the insertion work of the upper connecting pin 39.

  The lifting handrail 46 includes a vertical rod member 46a having a solid circular cross section extending in the longitudinal direction close to the intermediate connection member 37, a mounting arm 37d projecting from the front of the upper end portion of the intermediate connection member 37, and a lower rear The mounting arm 37d is inserted into a bifurcated portion 46b formed at the upper end of the vertical bar member 46a, and a pin is provided at the overlapping portion of each other. The raising and lowering handrail 46 is fixed to the intermediate connection member 37 by inserting the fixing pin 48 into the holes 37 e and 46 c and holding it by the split pin 49. In the state where the rear leg 31 is contracted, the vertical bar member 46a penetrates the engagement hole 35d provided in the engagement arm 35c, the third raising and lowering step 42c, and the first raising and lowering step 42a, and the upper end portion thereof The upper end portion of the vertical bar member 46a is a mounting arm in a state where it is disposed along the front surface of the lower rear leg 35 by engaging with the mounting arm 37d and the engagement hole 35d (FIG. 7) and the rear leg 31 is extended. The lower end portion is disposed along the front surface of the intermediate connection member 37 by engaging the lower end with the engagement hole 35d (FIG. 8). As described above, the vertical bar member 46 a slides integrally with the intermediate connection member 37 while maintaining the engagement with the engagement arm 35 c as the rear leg 31 expands and contracts.

  The work handrails 47 are mounted with a horizontal bar member 47a having a solid circular cross section extending in the width direction of the upper swing body 14 and a rear end surface of the pair of left and right middle connection members 37, 37 by bolts 50. It has arms 47b and 47b, and allows the horizontal bar member 47a to pass through the round hole 47c provided in the mounting arm 47b, and also has a flange portion 47d provided at one end of the horizontal bar member 47a and a split provided at the other end. In a state where the pin 51 and the stopper 51 are prevented from coming off, the upper end portion of the pair of left and right intermediate connection members 37 and 37 is bridged.

  Here, the procedure of inserting the upper connecting pin 39 and the lower connecting pin 38 and fixing the gantry 23 in a standing state will be described. First, using a step (not shown) such as a stepladder, each connecting pin 38, 39 fixing the rear leg 31 of the gantry 23 in the collapsed state is removed, and the rear leg 31 can be extended. Do. The extracted connection pins 38 and 39 are stored in the pin storage portion 43e. Next, when the gantry relief cylinder 33 is extended and the upper end of the front leg 30 is raised, the upper rear leg 36 and the intermediate connecting member 37 extend like a fishing rod while rotating the lower rear leg 35 forward. The extension operation is restricted by the engagement of the retaining members (not shown) provided at the overlapping portions in a state where the upper rear leg 36, the intermediate connecting member 37 and the lower rear leg 35 are substantially upright. Be done. As a result, the respective corresponding hole positions of the upper pin insertion holes 36 c and 37 b and the lower pin insertion holes 35 a and 37 c coincide with each other, and the connection pins 38 and 39 can be inserted.

  Subsequently, the vehicle travels to the left side of the lower traveling body 12 and takes a foot on the getting on / off step 12b to ascend to the crawler 12a. Further, when going up to the floor frame 14a, it climbs to the top plate 17a of the engine room 17 in the stairs 20, moves backward on the top plate 17a and moves to the left rear leg 31 of the gantry 23 paying attention to the step of the foot. Here, the hook of the safety band is attached to the lifting and lowering handrail 46, and the lower connection pin 38 taken out from the pin storage portion 43e is inserted into the lower pin insertion holes 35a and 37c to prevent the beta pin 40 from coming off.

  Then, while grasping the lifting handrail 46, the first raising and lowering step 42a, the second raising and lowering step 42b, the third raising and lowering step 42c, and the footing plate 43a are alternately hooked in this order to rise to the work bench 43. Next, change the hooks of the safety belt from the lifting and lowering handrail 46 to the working handrail 47, insert the upper connecting pin 39 taken out from the pin storage 43e into the upper pin insertion holes 36c and 37b, and stop the beta pin 40 Do.

  Subsequently, the work table 43 is moved laterally, and the upper connection pin 39 taken out from the pin storage 43e is inserted through the upper pin insertion holes 36c and 37b in the same manner in the rear leg 31 on the right side Stop it. Next, the hooks of the safety belt are changed from the working handrail 47 to the raising and lowering handrail 46, and while grasping the raising and lowering handrail 46, the third raising and lowering step 42c, the second raising and lowering step 42b, and the first raising and lowering step 42a are alternated in order. Get down on the top plate 16a of the equipment room 16 by putting. Next, the lower connection pin 38 taken out of the pin storage portion 43e is inserted into the lower pin insertion holes 35a and 37c, and the beta pin 40 prevents the lower connection pin 38 from coming off. Finally, the hooks of the safety belt are removed from the lifting handrail 46, and from the top plate 16a, the ladder 19 is lowered from the top plate 16 onto the crawler 12a, and the landing step 12b is footed down to the ground. In this procedure, the operation of inserting the upper connecting pin 39 and the lower connecting pin 38 into the pair of left and right rear legs 31, 31 is completed, and the gantry 23 is fixed in a standing state.

  As described above, the lower rear leg 35 is provided with the lifting step 42 and the work table 43 which are the scaffolding 41 on which the operator who performs the insertion work of the upper connecting pin 39 moves, and the hook of the safety belt can be detached from the intermediate connecting member 37 Since the elevation handrail 46 and the work handrail 47 which are the handrail portion 45 are provided, the upper connecting pin 39 can be inserted easily and safely without using a work vehicle.

  Also, a three-stage structure in which the lifting and lowering step 42 is vertically separated from the middle portion of the lower rear leg 35 in the order of the first lifting and lowering step 42a, the second lifting and lowering step 42b, and the third lifting and lowering step 42c. Since the work table 43 is constructed at the upper end of the pair of left and right lower rear legs 35, 35, the operator's lifting path is compactly formed along the back leg 31, and the work table 43 is It is possible to insert the upper connection pin 39 into the left and right two upper pin insertion holes 36c and 37b only by moving laterally, and the insertion work of the upper connection pin 39 can be performed more easily and quickly.

  Furthermore, the first raising and lowering step 42a and the third raising and lowering step 42c are provided on the front surface of the lower rear leg 35, and the second raising and lowering step 42b is provided on the outer surface of the lower rear leg 35. Are alternately arranged on the front and outer surfaces of the lower rear leg 35, and both ends of the work table 43 are extended correspondingly to the projecting position of the second lifting step 42b, so that it is easy to carry the foot during lifting and lowering And can be raised and lowered without difficulty along the rear leg 31.

  In addition, since the vertical bar member 46a is formed to slide integrally with the intermediate connection member 37 while holding the engaged state with the engagement arm 35c provided at the upper end portion of the lower rear leg 35, The vertical bar member 46 a can be disposed along the intermediate connection member 37 without interfering with the ups and downs and the expansion and contraction of the legs 31. Furthermore, since the lower end portion of the vertical bar member 46a is engaged with the engagement arm 35c when the gantry 23 is erected, rattling of the vertical bar member 46a can be suppressed, and the vertical bar member It is possible to move up and down more safely along the rear leg 31 while stably gripping the 46a.

  In addition, since the horizontal bar member 47a is installed at the upper end of the pair of left and right intermediate connection members 37, 37, the hook of the safety band may be attached to the horizontal bar member 47a to move safely on the work table 43. it can. Furthermore, it becomes possible to arrange the horizontal bar member 47a at the height of the height of the worker, and it is possible not only to avoid a dangerous state where the worker may fall down, such as stepping on the rope of the safety belt. First, when the worker slides his / her foot and falls from the work table 43, the falling distance can be shortened to reduce the impact load at the time of falling. Further, both ends of the horizontal bar member 47a and the upper end of the vertical bar member 46a can be disposed close to each other, and when changing the hook of the safety belt between the horizontal bar member 47a and the vertical bar member 46a The non-attachment state can be reduced.

  Furthermore, since the pin storage portion 43e for storing the upper connection pin 39 and the lower connection pin 38 is provided on the work table 43, when the gantry 23 is raised or fallen, the corresponding pins 38 are inserted through the corresponding pins It is possible to prepare in advance in the vicinity of the hole, and it is not necessary to lift and lower the gantry 23 by holding the heavy connecting pins 38 and 39.

  The present invention is not limited to the embodiment described above, and the number of steps of the lifting step and the size of the work table are arbitrary, and the scaffolding is appropriately made according to conditions such as the length of the rear leg and the rear shape of the upper swing body. Can be configured. Further, the mounting positions of the lifting handrail and the work handrail are not limited to the above-described embodiment but can be appropriately changed according to the scaffolding. Furthermore, the procedure of attaching and detaching the upper connecting pin and the lower connecting pin is optional, for example, the attaching and detaching of each connecting pin may be performed first from the rear leg on the right side. Moreover, in the said embodiment, although the pile driver was illustrated as a construction machine, it can apply to the various construction machines which mount a gantry in the back part of a revolving super structure, such as an earth drill and a crane.

  11: pile driving machine, 12: lower traveling body, 12a: crawler, 12b: step for getting on and off, 13: swing bearing, 14: upper swing body, 14a: floor frame, 15: driving room, 16: equipment room, 16a ... Top board, 17 ... engine room, 17 a ... top board, 18 ... inspection door, 19 ... ladder, 20 ... stair, 21 ... rear jack, 22 ... outrigger box, 23 ... gantry, 24 ... uphill winch, 25 ... uplift rope, 26: Gantry sieve, 27, 28: Gantry sieve block, 29: connecting arm, 30: front leg, 31: rear leg, 32: sheave pivot, 33: gantry relief cylinder, 34: connecting arm, 35: lower rear leg, 35a: lower pin insertion hole, 35b: bracket, 35c: engagement arm, 35d: engagement hole, 36: upper rear leg, 36a: lower pin insertion hole, 36b, 36c: upper pin insertion , 37: intermediate connecting member, 37a: lower pin insertion hole, 37b: upper pin insertion hole, 37c: lower pin insertion hole, 37d: mounting arm, 37e: pin insertion hole, 38: lower connection pin, 39: upper connection pin , 40: Beta pin, 41: Scaffolding, 42: Lifting step, 42a: First lifting step, 42b: Second lifting step, 42c: Third lifting step, 43: Work bench, 43a: Scaffolding plate, 43b: Horizontal frame, 43c: Support plate, 43d: Round hole, 43e: Pin storage portion, 43f: Round hole, 43g: Locking piece, 44: Bolt, 45: Handrail, 46: Lifting handrail 46a: Vertical bar member, 46b ... bifurcated portion, 46c ... pin insertion hole, 47 ... work handrail, 47a ... horizontal bar member, 47b ... mounting arm, 47c ... round hole, 47d ... flange portion, 48 ... fixed pin, 49 ... split pin, 50 ... bolt , 5 ... split pin

Claims (5)

  The lower end includes a pair of left and right front legs rotatably mounted on the front side of the upper swing body, and a pair of left and right rear legs provided between the upper end portion of the front leg and the rear side of the upper swing body. The rear leg has a lower rear leg whose lower end is rotatably mounted on the upper swing body, and an upper rear leg whose upper end is rotatably mounted on an upper end of the front leg, and the lower portion The upper end of the rear leg and the lower end of the upper rear leg are telescopically connected by sliding in the longitudinal direction with each other through the intermediate connection member, and the rear leg is extended and raised by raising the upper end of the front leg In a construction machine provided with a gantry in which the rear leg is contracted to be in a collapsed state by lowering the upper end of the front leg, the lower rear leg and the intermediate connection member in a state where the gantry is erected. In the lower pin insertion hole provided in the overlapping part of the Lower connecting pin and an upper connecting pin inserted through an upper pin insertion hole provided in the overlapping portion of the upper rear leg and the intermediate connecting member, and the upper connecting pin is inserted into the lower rear leg. A construction machine comprising: a footing provided to move a worker, and the intermediate connection member being provided with a handrail portion to which a hook of a safety belt attached to the worker's body can be attached and detached.   The scaffolding is characterized in that the scaffold is a work bench constructed on the upper end portion of the pair of left and right lower rear legs, and a plurality of steps provided on the side surfaces of the lower rear legs and vertically separated. A construction machine according to item 1.   The handrail portion is attached to a mounting arm whose upper end is provided at the upper end portion of the intermediate connection member, and the vertical bar member disposed in a state along the intermediate connection member, and the vertical direction at the upper end portion of the rear leg The construction machine according to claim 1 or 2, further comprising: an engagement arm slidably holding the lower portion of the rod member.   The construction machine according to any one of claims 1 to 3, wherein the handrail portion includes a horizontal bar member that is bridged to upper end portions of the left and right pair of intermediate connection members.   The construction machine according to any one of claims 2 to 4, wherein a pin storage portion for storing the upper connection pin and the lower connection pin is provided on the work table.

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