JP2012236659A - Gantry structure of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase operation safety and operation easiness while preventing generation of impact noise or damage of a member due to impact between a rear leg and a connection bar in an operation state of a gantry.SOLUTION: This gantry 5 includes a front leg 22 and a rear leg 25 obtained by connecting a plurality of members 26, 27 in a foldable manner. In an operation state, each member of the rear leg is vertically extended and the front leg is inclined backward and upward. In a storage state, each member of the rear leg is folded, and the front leg is tilted backward above the rear leg. One end of a connection bar 41 connecting a head of the front leg with a base side in the storage state of the gantry to hold the storage state is connected to the head 22a of the front leg in a manner rotatable about a support shaft 42. A torsion coil spring 51 generating spring force in a direction causing the connection bar to abut against the rear leg of the gantry in the operation state of the gantry is provided around the support shaft, and a cushion member 52 is attached to the other end side of the connection bar or a region of the rear leg corresponding thereto, for avoiding direct contact between both.

Description

  The present invention relates to a gantry structure for a construction machine such as a crawler crane or a pile driving machine, and particularly relates to a structure in which a rear leg of a gantry is folded and a front leg is tilted backward during conveyance of the construction machine.

  In general, in construction machines such as crawler cranes and pile driving machines, a work attachment is attached to the front side of the upper revolving structure on the revolving frame, and a work attachment is associated with the work attachment work on the rear side of the revolving frame. In order to perform a predetermined operation, for example, in a crawler crane, a boom as a work attachment is supported via a rope from behind, and in a pile driving machine, a leader is caused by a rope. Is attached).

  As such a gantry or gantry structure, as disclosed in Patent Document 1, for example, a front leg (also referred to as a front leg or a compression member) whose lower end is rotatably supported by a turning frame as a base. And a rear leg (also referred to as a rear leg or a tension member) whose one end is connected to the head portion on the upper end side of the front leg and the other end is rotatably connected to the revolving frame. The rear leg is composed of an upper rear leg and a lower rear leg that are divided into upper and lower parts so as to be foldable. In the working state, the upper rear leg and the lower rear leg of the rear leg extend vertically and the front leg is rearward. It is known that the upper leg and the lower rear leg of the rear leg are folded upward and tilted backward on the rear leg in the retracted state during transport. In addition, as a rear leg, what divides | segments into three members in the axial direction and connects the members so that folding is possible or slidable to an axial direction is also known (refer patent document 2 and patent document 3). .

  By the way, in such a gantry structure, in order to prevent the front leg and the rear leg from jumping up due to vibration or the like in the retracted state at the time of transportation, for example, as disclosed in Patent Document 4, the head part of the front leg is swung. A connecting rod for connecting to the frame and holding it in the retracted state may be provided. In that case, one end of the connecting rod is connected to the head portion of the front leg so as to be rotatable around the support shaft at a rear position relative to the connecting portion with the rear leg, and in a working state, the connecting rod is suspended vertically close to the rear leg. Therefore, it is necessary to prevent the collision between the two members and to prevent the occurrence of collision noise and damage to the member. For this reason, as disclosed in Patent Document 4, conventionally, an engaging pin is provided on the other end side of the connecting rod, and a hook member having a hook groove engaging with the engaging pin is attached to the rear leg. This is done in conjunction with connecting rod equipment.

JP 2000-198672 A JP 2002-154788 A JP-A-9-278368 JP 2011-37628 (page 3-4, FIG. 13, FIG. 14)

  However, in the above-described conventional one, it is necessary for an operator to engage or disengage the hook member and the engagement pin every time the state of the gantry is changed. There is a problem of becoming.

  In addition, when the construction machine is large, the rear leg of the gantry becomes long and the mounting position of the hook member corresponding to the engaging pin on the other end side of the connecting rod becomes high, so that the operator's hand is difficult to reach the hook member. As a result, there is a problem that the work becomes dangerous.

  The present invention has been made in view of the above points, and the problem is that the structure using a torsion coil spring or the like instead of the conventional structure using a hook member or the like is connected in the working state of the gantry. It is an object of the present invention to provide a gantry structure for a construction machine that can improve the safety of work and the ease of work while preventing the occurrence of collision sound and damage to members due to the collision between a rod and a rear leg.

  In order to solve the above-described problems, the invention according to claim 1 is configured such that a gantry is mounted on a base of a construction machine as a gantry structure of a construction machine, and the lower end of the gantry is rotatable to the base. The front leg is supported, and the rear leg has one end connected to the head portion on the upper end side of the front leg and the other end pivotally connected to the base. The rear leg is divided in the axial direction. A plurality of members can be folded or slidably connected in the axial direction. In the gantry working state, the rear leg members extend vertically and the front legs tilt backward and upward, and in the gantry retracted state the rear legs It is assumed that each member is folded or slid in the shrinking direction and the front leg is tilted rearward thereon. Then, one end of a connecting rod for holding the retracted state by connecting the head portion of the front leg to the base side in the retracted state of the gantry is supported at a position behind the connecting portion with the rear leg of the head portion of the front leg. It is connected so that it can rotate around its axis. In addition, a torsion coil spring is provided around the support shaft to generate a spring force in a direction in which the connecting rod comes into contact with the rear leg of the gantry in the working state of the gantry. Attach a cushioning material to avoid direct contact between the rear legs. Furthermore, the spring force (torsional reaction force) of the torsion coil spring acts as a force for pressing the lower end side of the connecting rod against the gantry rear leg through the cushion material when the gantry rear leg extends in the vertical direction. When the rear leg of the gantry is changed from the working state to the retracted state, the weight is less than the weight moment load of the connecting rod, and the connecting rod is set so as to be suspended vertically from the head portion of the front leg. Make the configuration.

  In this configuration, in the working state of the gantry, the connecting rod is always brought into contact with the rear leg of the gantry by the spring force of the torsion coil spring provided around the support shaft that is a connecting portion between the one end and the head portion of the front leg. Since the cushioning material is interposed between the other end of the connecting rod and the rear leg, the direct contact between the connecting rod and the rear leg can be prevented, and both members are The impact force when colliding indirectly through the cushioning material is greatly reduced.

  On the other hand, when the rear leg of the gantry is changed from a working state in which the rear leg extends in the vertical direction to a retracted state in which the rear leg is folded or slid in the contraction direction and the front leg is tilted rearward thereon, the spring force of the torsion coil spring is The connecting rod is set to be in a state where it is suspended from the head part of the front leg in a state where it is smaller than the load moment load of the connecting rod, and is retracted from the working state of the gantry by the spring force of the torsion coil spring. There will be no hindrance to the change operation to, and there will be no hindrance to connect the other end of the connecting rod to the base in the retracted state. In addition, it is not necessary to perform operations such as engagement and release of the hook member and the engagement pin at a high position as in the prior art, and the safety and ease of operation can be improved.

  As described above, according to the gantry structure of the construction machine according to the present invention, in the working state of the gantry, the connecting rod is the spring force of the torsion coil spring provided on the support shaft that is the connecting portion between the one end and the head portion of the front leg. The other end side is always pressed against the rear leg of the gantry, and a cushioning material is interposed between the other end side of the connecting bar and the rear leg. In addition, the impact force when the two members collide indirectly through the cushioning material can be greatly reduced. As a result, the generation of collision noise and damage to the member due to the collision can be prevented. can do. In addition, the spring force of the torsion coil spring hinders the change operation from the working state of the gantry to the retracted state, or interferes with connecting the other end of the connecting rod to the base side in the retracted state. In addition, there is no need to perform operations such as engagement and release of the hook member and the engagement pin at a high position as in the prior art, and the safety and ease of operation can be effectively improved in practice.

FIG. 1 is a side view of a crawler crane according to a first embodiment of the present invention. FIG. 2 is a side view showing a structure near the gantry of the crawler crane. FIG. 3 is a side view showing a working state of the gantry. FIG. 4 is a side view showing a state in which the upper rear leg and the lower rear leg have started to be folded in order to change from the working state of the gantry to the retracted state. FIG. 5 is a side view showing a retracted state of the gantry. FIG. 6 is an enlarged view in which a part near X in FIG. 3 is cut open. FIG. 7 is a view as seen from the Y direction in FIG. FIG. 8 shows a torsion coil spring, where (a) is a front view and (b) is a right side view. FIG. 9 is a characteristic diagram showing the relationship between the spring force of the torsion coil spring and the weight moment load of the connecting rod. FIG. 10 is a view corresponding to FIG. 6 showing the second embodiment. FIG. 11 is also equivalent to FIG. FIG. 12 is equivalent to FIG.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments that are modes for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows an overall configuration of a crawler crane as a construction machine equipped with a gantry structure according to a first embodiment of the present invention, where 1 is a crawler type lower traveling body and 2 is turnable on the lower traveling body 1 The upper revolving body 2 has a revolving frame 3 as a base, and the base end of the boom 4 as a work attachment can be raised and lowered at the front part of the revolving frame 3 A gantry 5 and a counterweight 6 are attached to the rear part of the revolving frame 3.

  One end of a boom guy line 7 is fixed to the tip of the boom 4, and an upper spreader 8 is provided at the other end of the boom guy line 7. A boom hoisting rope 10 is wound around the upper spreader 8 and a lower spreader 9 attached to the top of the gantry 5. One end of the boom hoisting rope 10 is fixed to the gantry 5, and the other end is The boom swing drum 11 provided at the rear of the upper swing body 2 (specifically, the swing frame 3) is wound around. Then, by extending or winding the boom hoisting rope 10 by the boom hoisting drum 11, the distance between the lower spreader 9 and the upper spreader 8 is changed short or long to raise and lower the boom 4.

  A boom point sheave 12, an idler sheave 13, and an auxiliary sheave 14 are rotatably provided at the tip of the boom 4. A main hook 15 is supported and suspended from the boom point sheave 12 by a main hoisting rope 16, and an auxiliary hook 17 is supported and suspended from the auxiliary sheave 14 by an auxiliary hoisting rope 18. One end of the main hoisting rope 16 is fixed to the tip of the boom 4, while the other end of the main hoisting rope 16 is passed through the boom point sheave 12 through the idler sheave 13 to the main swing body 2. The main hook 15 is wound up or down by the main winding drum 19 via the main winding upper rope 16. One end of the auxiliary winding upper rope 18 is coupled to the auxiliary hook 17, while the other end of the auxiliary winding upper rope 18 passes from the auxiliary sheave 14 through the idler sheave 13 to the auxiliary revolving body 2. The auxiliary hook 17 is wound up or down by the auxiliary winding drum 20 via the auxiliary winding upper rope 18.

  As shown in FIG. 2, the revolving frame 3 of the upper revolving structure 2 is formed by connecting a pair of left and right side wall portions 3a (shown only on the right side) by a bottom surface portion 3b. Between the pair of left and right side wall portions 3a of the swivel frame 3, a main winding drum 19, an auxiliary winding drum 20, and a boom hoisting drum 11 are arranged in a horizontal position with the drum rotation axis directed in the horizontal width direction from the front side. Although not shown, it is attached to the side wall portion 3a or the bottom surface portion 3b of the revolving frame 3 via a mounting bracket or the like.

  On the other hand, as shown in FIG. 2 and as shown in detail in FIGS. 3 to 5, the gantry 5 has a pair of left and right ends whose lower ends are supported by the side wall 3 a of the revolving frame 3 so as to be rotatable around the support shaft 21. One end (upper end) of the front leg 22 (only the right side is shown) and a head portion (a portion corresponding to the top of the gantry 5) 22a on the upper end side of the front leg 22 are rotatably connected around the support shaft 23, Each end (lower end) has a pair of left and right rear legs 25 (only the right side is shown) connected to the side wall 3a of the revolving frame 3 so as to be rotatable around the support shaft 24. The rear leg 25 is divided into an upper rear leg 26 and a lower rear leg 27 which are two members in the axial direction, and the ends of both the members 26 and 27 are folded by two upper and lower connecting pins 28 and 29. Connected as possible. Of the two connecting pins 28 and 29, the upper connecting pin 28 has pin holes 31 and 32 (see FIG. 4) provided at the lower end of the upper rear leg 26 and the upper end of the lower rear leg 27, respectively. In this state, the lower connecting pin 29 is inserted into both the pin holes 31 and 32. The lower connecting pin 29 has a pin hole 33 (see FIG. 4) provided at the lower end of the upper rear leg 26 and the lower rear leg 27. It is inserted into the pin hole 33 and the long hole 34 in a state where the upper end of the long hole 34 provided in the upper end portion is coincident. In the working state of the gantry 5, as shown in FIG. 3, the upper rear leg 26 and the lower rear leg 27 of the rear leg 25 extend in the vertical direction and the front leg 22 is inclined rearward upward. As shown in FIG. 5, after removing the connecting pin 28, the upper rear leg 26 and the lower rear leg 27 are folded around the connecting pin 29, and the front leg 22 is tilted backward to a horizontal state thereon. It has become.

  The gantry 5 has a hydraulic cylinder 36 provided between the lower part of the front leg 22 and the side wall 3 a of the revolving frame 3, and the front leg 22 of the gantry 5 is expanded and contracted by the hydraulic cylinder 36. Rotates around the support shaft 21. A connecting shaft 37 extending in the lateral width direction is installed between the head portions 22 a of the left and right front legs 22 of the gantry 5, and the lower spreader 9 is attached to the connecting shaft 37. As shown in FIGS. 6 and 7, the head portion 22a of the front leg 22 includes a pair of side plates 40 and 40 facing each other with the connection plates 38 and 39 interposed therebetween, and the connecting shaft 37 is connected to a pair of the head portions 22a. One end of the rear leg 25 (specifically, the upper rear leg 26) is inserted between the pair of side plates 40, 40 of the head portion 22a via the support shaft 23. It is connected so that it can rotate.

  Further, one end of the connecting rod 41 is inserted between the pair of side plates 40 and 40 of the head 22a at a position on the rear upper side of the support shaft 23 which is a connecting portion with the rear leg 25 in the head portion 22a of the front leg 22. With the support shaft 42, the support shaft 42 is rotatably connected around the support shaft 42. As shown in FIG. 5, the connecting rod 41 includes a pin hole 43 provided at the other end of the connecting rod 41 in the retracted state of the gantry 5 and a pin hole provided at the rear end of the side wall 3a of the revolving frame 3 (not shown). And the coupling pin 44 is inserted into both the pin holes 43 and coupled to each other, thereby connecting the head portion 22a of the front leg 22 to the revolving frame 3 and maintaining the retracted state of the gantry 5. In addition, the connecting rod 41 is configured by connecting a pair of rod-like plates 45, 45 facing each other with a predetermined gap through a pair of connecting plates 46, 46 at two positions on both ends in the longitudinal direction.

  As a feature of the present invention, a torsion that generates a spring force around the support shaft 42 in a direction in which the connecting rod 41 is brought into contact with the upper rear leg 26 of the rear leg 25 of the gantry 5 in the working state of the gantry 5. A coil spring 51 is provided, and on the other end side (lower end side) of the connecting rod 41, the connecting rod 41 and the upper rear leg are disposed on the connection plate 46 on the side facing the upper rear leg 26 of the rear leg 25. A rubber cushioning material 52 for avoiding the direct contact of 26 is attached by screwing or the like.

  As shown in an enlarged detail in FIG. 8, the torsion coil spring 51 is formed by first folding a steel wire into two at the center and then placing coil portions 51b at intermediate portions between the folded portion 51a and both ends of the steel wire. And forming both ends of the steel wire to the opposite side to the folded portion 51a with the coil portion 51b interposed therebetween, and finally bending the both ends of the steel wire in opposite directions to form the locking portions 51c and 51c. It is what is done. The torsion coil spring 51 is disposed in a gap between the pair of rod-like plates 45 and 45 of the connecting rod 41, and the support shaft 42 passes through the pair of coil portions 51 b and 51 b of the torsion coil spring 51. . The folded portion 51 a of the torsion coil spring 51 is locked to a boss 53 fixed between the pair of rod-like plates 45 and 45 of the connecting rod 41, and the pair of locking portions 51 c and 51 c of the torsion coil spring 51 is The connecting rod 41 extends from the gap between the pair of rod-like plates 45, 45 to the gap between the pair of side plates 40, 40 of the head portion 22 of the front leg 22, and is locked to the end face of the corresponding side plate 40, respectively. Yes.

  The spring force (torsional reaction force) of the torsion coil spring 51 is the working state of the gantry 5 when the folding angle of the rear leg 25 is zero, that is, the rear leg 25 extends in the vertical direction, as shown by line A in FIG. When the connecting rod 41 is in a state parallel to the upper rear leg 26 of the rear leg 25, a minimum spring force (initial spring force) is generated, and the connecting rod 41 is parallel to the upper rear leg 26 of the rear leg 25. As the folding angle θ (see FIGS. 4 and 5) of the rear leg 25 increases, the rear leg 25 increases relatively slowly while maintaining the above state. On the other hand, when the folding angle θ of the rear leg 25 increases from zero while maintaining the state where the connecting bar 41 is parallel to the upper rear leg 26 of the rear leg 25, the weight moment load of the connecting bar 41 (centering on the support shaft 42). The moment load due to the weight of the connecting rod 41 is zero when the connecting rod 41 is in a vertical state, as indicated by line B in FIG. 9, and is relatively abrupt as the folding angle θ of the rear leg 25 increases. It has come to increase. In other words, the spring force of the torsion coil spring 51 is such that when the rear leg 25 of the gantry 5 extends in the vertical direction, the lower end side of the connecting rod 41 is placed on the lower leg side of the gantry 5 via the cushion material 52. It acts as a pressing force on the upper rear leg 26, and after the initial time when the rear leg 25 of the gantry 5 is changed from the working state to the retracted state (when the bending angle θ of the rear leg 25 is θa), the connecting rod 41 It is set so that it becomes smaller than the self-weight moment load and the connecting rod 41 is suspended vertically from the head portion 22 a of the front leg 22.

  Next, the operational effects of the first embodiment will be described. In the working state of the gantry 5 in which the rear leg 25 of the gantry 5 extends in the vertical direction, the connecting rod 41 has one end (upper end) and the head of the front leg 22. The other end side (lower end side) is always pressed in the direction in which it abuts against the upper rear leg 26 of the rear leg 25 by the spring force of the torsion coil spring 51 provided around the support shaft 42 which is a connecting part with the part 22a. In addition, since the cushion material 52 is interposed between the other end side of the connecting rod 41 and the upper rear leg 26 of the rear leg 25, direct collision between the connecting rod 41 and the upper rear leg 26 of the rear leg 25 is prevented. In addition, the impact force when the two members 41 and 26 collide indirectly via the cushion material 52 can be greatly reduced. As a result, it is possible to prevent the occurrence of a collision sound and the damage of both members 41 and 26 due to the collision.

  On the other hand, when the rear leg 25 of the gantry 5 is folded from the vertically extended working state and changed to a retracted state in which the front leg 22 is tilted backward, the spring force of the torsion coil spring 51 is reduced to the connecting rod. 41 is set so that the connecting rod 41 is suspended vertically from the head portion 22 a of the front leg 22, and the work of the gantry 5 is performed by the spring force of the torsion coil spring 51. There is no hindrance to the change operation from the state to the stowed state, nor the trouble of connecting the other end of the connecting rod 41 to the side wall 3a of the revolving frame 3 in the stowed state. In addition, it is not necessary to perform operations such as engagement and release of the hook member and the engagement pin at a high position as in the prior art, and the safety and ease of operation can be improved.

  FIG. 10 to FIG. 12 show a modified example of the torsion coil spring 61 provided around the support shaft 42 that is a connecting portion between one end of the connecting rod 41 and the head portion 22a of the front leg 22 as a second embodiment of the present invention. It is shown.

  That is, the torsion coil spring 61 is similar to the torsion coil spring 51 in the first embodiment. First, the steel wire is folded in half at the center, and then the folded portion 61a and both ends of the steel wire are connected. The coil portions 61b are respectively formed in the intermediate portion, both ends of the steel wire are extended to the opposite side to the folded portion 61a with the coil portion 61b interposed therebetween, and finally the both ends of the steel wire are bent in opposite directions to each other, thereby engaging portions 61c. 61c, the length between the folded portion 61a and the coil portion 61b of the torsion coil spring 61 is larger than that of the torsion coil spring 51 in the first embodiment. Is also set longer. The folded portion 61 a of the torsion coil spring 61 is locked to the fixed plate 46 on the opposite side of the rear leg 25 on one end side (upper end side) of the connecting rod 41. In addition, the other structure of 2nd Embodiment including the torsion coil spring 61 is the same as that of the case of 1st Embodiment, The same code | symbol is attached | subjected to the same member and the description is abbreviate | omitted. Also, in the second embodiment, it is needless to say that the same operational effects as in the first embodiment can be obtained.

  In addition, this invention is not limited to the said 1st and 2nd embodiment, Other various forms are included. For example, in each of the above-described embodiments, the connecting rod 41 is connected to a pair of rod-like plates 45, 45 facing each other with a predetermined gap through two pairs of fixing plates 46, 46 at two positions on both ends in the longitudinal direction. Although comprised, this invention is not restricted to the connection rod 41 of such a structure, A connection rod may be comprised by one rod-shaped member or a hollow member, or may be comprised by connecting several members. .

  Further, in each of the above-described embodiments, the rear leg 25 of the gantry 5 is divided into the upper rear leg 26 and the lower rear leg 27 which are two members in the axial direction, and the ends of both the members 26 and 27 are connected to each other. Although the case where the upper and lower two connecting pins 28 and 29 are connected so as to be foldable has been described, the present invention is such that the rear leg of the gantry is divided into three members in the axial direction and the members can be folded. Of course, the present invention can be similarly applied to a case where the shafts are slidably connected in the axial direction.

3 Revolving frame (base)
5 Gantry 22 Front leg 22a Head part 23 Support shaft (connecting part)
25 Rear leg 26 Upper rear leg 27 Lower rear leg 41 Connecting rod 42 Support shaft 51, 61 Torsion coil spring 52 Cushion material

Claims (1)

A gantry is mounted on the base of the construction machine. This gantry has a front leg whose lower end is rotatably supported by the base, one end at the head portion on the upper end side of the front leg, and the other end at the base. The rear legs are connected to each other so as to be rotatable, and the rear legs are formed by connecting a plurality of members divided in the axial direction so that they can be folded or slidable in the axial direction. Then, each member of the rear leg extends in the vertical direction and the front leg is inclined rearward and upward, and in the retracted state of the gantry, each member of the rear leg is folded or slid in the contraction direction, and the front leg is tilted rearward thereon. In the gantry structure of construction machinery constructed in
One end of a connecting rod for holding the head in the retracted state by connecting the head portion of the front leg to the base side in the retracted state of the gantry at the rear of the connecting portion with the rear leg is supported by the head portion of the front leg. It is connected so that it can rotate around,
Around the support shaft is provided a torsion coil spring that generates a spring force in a direction in which the connecting rod comes into contact with the rear leg of the gantry in the working state of the gantry. A cushioning material is attached to the corresponding rear leg to avoid direct contact between the two.
The spring force of the torsion coil spring acts as a force for pressing the lower end side of the connecting rod against the gantry rear leg through the cushion material when the gantry rear leg extends in the vertical direction. Construction characterized in that when the working state is changed to the retracted state, it is set so that the connecting rod is suspended from the head part of the front leg so that it is smaller than the weight moment load of the connecting rod. The gantry structure of the machine.