JP2020164260A - Construction machine - Google Patents

Abstract

To provide a construction machine with a telescopic boom and a jib capable of preventing a main hook from touching a tension rod when the jib is overhung.SOLUTION: A construction machine has a derrickable boom, a hook hung from a boom head, a jib connected rotatably to the boom, and a jib derricking mechanism to derrick the jib. The jib has a pair of jib base end parts connected rotatably to the boom head. The jib derricking mechanism has a tension rod one end of which is connected to the jib and the other end of which is connected to the boom head, and a protection mechanism to prevent the hook running between the pair of jib base end parts from direct contacting the tension rod during overhanging the jib. The protection mechanism has a guard member to cover at least an inner surface of the tension rod, and a supporting structure to support the guard member with a gap formed between the tension rod and the guard member.SELECTED DRAWING: Figure 5

Description

The present invention relates to a construction machine with a boom and a jib.

Generally, a crane device mounted on a self-propelled crane or the like includes a boom and a jib for supplementing the length of the boom, as disclosed in, for example, Patent Document 1. When not in use, the jib is stowed along the longitudinal direction of the boom with its base end facing the tip of the boom and the tip facing the base of the boom. Further, when the jib is used, the jib is projected to the front of the boom by being rotated from the storage position around the support portion in a state where the base end thereof is supported by the tip end portion of the boom.

Japanese Patent No. 4683971

When overhanging the jib, the main hook must be passed between the bifurcated base ends of the jib. When the main hook passes, there is a concern that the main hook may come into contact with or collide with the tension rod. Contact or collision between the main hook and the tension rod causes damage to the tension rod. Therefore, it is desirable to avoid contact and collision between the main hook and the tension rod.

The present invention has been made in consideration of such an actual situation, and an object of the present invention is to construct a boom and a jib in which the main hook is prevented from coming into contact with the tension rod when the jib is extended. To provide a machine.

The construction machine according to the present invention is rotatably connected to the undulating boom, a hook suspended from a boom head provided at the tip of the boom, and the boom to compensate for the length of the boom. It has a jib and a jib undulation mechanism for undulating the jib. The jib has a pair of bifurcated jib base ends. The ends of the pair of jib base ends are rotatably connected to the boom head. The jib undulation mechanism includes a tension rod having one end connected to the jib and the other end connected to the boom head, and the hook passing between the pair of jib base ends between the overhangs of the jib. It has a protection mechanism that prevents direct contact with the tension rod. The protection mechanism has a guard member that covers at least the inner surface of the tension rod, and a support structure that supports the guard member in a state where a space is formed between the tension rod and the guard member. ing.

According to the present invention, there is provided a construction machine having a boom and a jib in which the main hook is prevented from coming into contact with the tension rod when the jib is extended.

FIG. 1 shows a crane vehicle which is a construction machine according to the first embodiment. FIG. 2 is a perspective view of the jib undulation mechanism shown in FIG. 1, showing the jib undulation mechanism in a state where the boom is in the maximum standing position. FIG. 3 is a perspective view of the protection mechanism and the tension rod shown in FIG. 2, and in FIG. 3, the support structure and the guard member of the protection mechanism are disassembled and drawn. FIG. 4 is a perspective view of the protection mechanism and the tension rod shown in FIG. 2, and FIG. 4 shows the assembled protection mechanism. FIG. 5 is a vertical cross-sectional view of the protection mechanism shown in FIG. 4 along the central axis of the tension rod. FIG. 6 is a cross-sectional view of the support structure along the line 13F-13F shown in FIG. FIG. 7 is a perspective view of the telescopic boom, the boom head, and the jib undulating mechanism shown in FIG. 2, and shows the main hook in contact with the protection mechanism. FIG. 8 is a perspective view of the telescopic boom, the boom head, and the jib undulating mechanism shown in FIG. 2 as viewed from a direction different from that of FIG. 7, and shows how the main hook contacts the protection mechanism. FIG. 9 is a perspective view of the protection mechanism and its peripheral portion before contact between the main hook and the protection mechanism. FIG. 10 is a perspective view of the protection mechanism and its peripheral portion before contact between the main hook and the protection mechanism as viewed from a direction different from that of FIG. FIG. 11 is a perspective view of the protection mechanism and its peripheral portion as viewed from the same direction as in FIG. 9 after the contact between the main hook and the protection mechanism. FIG. 12 is a perspective view of the protection mechanism and its peripheral portion as viewed from the same direction as in FIG. 10 after the contact between the main hook and the protection mechanism. FIG. 13 is a perspective view of the telescopic boom, the boom head, and the jib undulating mechanism shown in FIG. 2, and shows how the main winding wire rope comes into contact with the protection mechanism. FIG. 14 is a perspective view of the protection mechanism and the tension rod according to the second embodiment. FIG. 15 is a perspective view of the protection mechanism and the tension rod according to the second embodiment as viewed from a direction different from that of FIG.

[First Embodiment]
The first embodiment will be described with reference to FIG. FIG. 1 shows a crane vehicle which is a construction machine according to the first embodiment.

As shown in FIG. 1, the crane vehicle 10 includes a traveling vehicle body 12 and a swivel body 18 provided so as to be rotatable on the traveling vehicle body 12.

The traveling vehicle body 12 has a plurality of wheels 14 for movement. The wheel 14 is configured to be driveable by a drive mechanism (not shown). Some wheels 14 are steerable by a steering mechanism (not shown). Further, the traveling vehicle body 12 has outriggers 16 on both front and rear sides for stably supporting the traveling vehicle body 12 with respect to the ground during crane operation.

The swivel body 18 includes a swivel base 20, a telescopic boom 24 undulatingly supported by the swivel base 20, and a cab 22 for operating the crane vehicle 10 and operating the crane operation. Further, a boom undulating device 26 for undulating the telescopic boom 24 is provided between the telescopic boom 24 and the swivel base 20.

The boom undulating device 26 includes a telescopic boom 24 and a boom undulating cylinder 28 connected to the swivel base 20. A main hook 62A is supported on the telescopic boom 24 via a main winding wire rope 54A (see FIGS. 7, 8 and 13).

Further, the swivel body 18 includes a jib 30 that supplements the length of the telescopic boom 24 and a jib undulation mechanism 32 that undulates the jib 30. The jib 30 extends along the longitudinal axis. The jib 30 is connected to the telescopic boom 24 when in use. Further, the jib 30 is stored between the lower surface of the telescopic boom 24 and the upper surface of the traveling vehicle body 12 along the lower surface of the telescopic boom 24 when not in use. In other words, the jib 30 is stored under the telescopic boom 24 in a lower hugging state. The jib undulation mechanism 32 is a structure integrated with the jib 30, and is stored together with the jib 30 when the jib 30 is not in use. A supplementary hook 62B is supported on the jib 30 via a supplementary winding wire rope 54B.

A jib connecting mechanism 34 for connecting the jib 30 to the telescopic boom 24 is provided between the telescopic boom 24 and the jib 30. The jib connecting mechanism 34 connects the jib 30 to the telescopic boom 24 when the jib 30 is arranged in the retracted position, and when the jib 30 is moved to the tip side of the telescopic boom 24 by the extension of the telescopic boom 24, the telescopic boom It is configured so that the 24 and the jib 30 are disconnected.

For example, the jib connecting mechanism 34 includes a jib connecting pin fixed to the telescopic boom 24 and a jib connecting ring fixed to the jib 30. The jib connecting pin extends parallel to the longitudinal axis of the telescopic boom 24 toward the tip end side of the telescopic boom 24. When the jib 30 is moved from the storage position to the tip end side of the telescopic boom 24 along the telescopic boom 24, the jib connecting pin comes off the jib connecting ring, so that the telescopic boom 24 and the jib 30 are disconnected. On the contrary, when the jib 30 is moved to the base end side of the telescopic boom 24 along the telescopic boom 24 and placed in the retracted position, the jib connecting pin is inserted into the jib connecting ring, so that the jib 30 is inserted into the telescopic boom 24. Are concatenated. A guide mechanism is provided to guide the jib 30 to an appropriate position when the jib 30 is moved during storage.

The driver's cab 22 is provided with a plurality of control devices such as an accelerator, a brake, and a steering wheel for self-propelling of the traveling vehicle body 12, and these control devices are configured to control the drive and steering of the wheels 14. Has been done. The driver's cab 22 is also provided with control devices such as a plurality of operation levers and operation pedals for crane work, and these control devices allow the swivel body 18 to swivel, the telescopic boom 24 to undulate and telescopic, and jib. It is configured so that the overhang of 30 and the like can be controlled.

Here, the jib undulation mechanism 32 will be described with reference to FIG. As shown in FIG. 2, the telescopic boom 24 includes a telescopic multi-stage boom 36 and a boom head 44 fixed to the tip of the tip boom of the multi-stage boom 36.

The boom head 44 includes a main winding guide sheave 46A on which the main winding wire rope 54A is hung, a supplementary winding guide sheave 46B on which the auxiliary winding wire rope 54B is hung, a boom top sheave 48A on which the main winding wire rope 54A is hung, and a jib. It has a rooster top sheave 48B on which the supplementary winding wire rope 54B is hung when the 30 is not in use. The main hook 62A is suspended by a main winding wire rope 54A hung on a main winding guide sheave 46A and a boom top sheave 48A. The auxiliary hook 62B is suspended by the auxiliary winding wire rope 54B hung on the auxiliary winding guide sheave 46B and the rooster top sheave 48B when the jib 30 is not in use.

The boom head 44 also includes a boom link 64. One end of the boom link 64 is pivotally supported by a shaft 66 of the boom head 44, and is rotatably connected to the boom head 44. The boom head 44 further includes a boom link stopper 68 that receives the boom link 64.

The jib 30 is composed of a jib rear portion 70 and a jib front portion 76. Here, the side where the jib 30 is connected to the boom head 44 is the rear side, and the opposite side is the front side. The rear end of the jib 30 is referred to as the base end, and the front end of the jib 30 is referred to as the tip. Further, the upper and lower sides shall be defined based on the state in which the jib 30 is horizontally overhanging. Further, the left and right sides are defined with reference to the direction from the rear to the front of the jib 30.

The jib rear portion 70 has a bifurcated jib base end portions 72L, 72R, in other words, a pair of jib base end portions 72L, 72R extending bifurcated. The pair of jib base end portions 72L and 72R extend at intervals that allow the main hook 62A to pass through. Each of the jib base end portions 72L and 72R has a jib foot portion 74 connected to the boom head 44 at the rear end portion. The jib foot portion 74 is configured to be detachably connected to the boom top sheave shaft 52 of the boom head 44 by a jib foot pin. For example, the jib foot portion 74 has a bifurcated fork portion having a recess that engages with the boom top sheave shaft 52, and a jib foot pin insertion hole formed at each of the pair of end portions of the fork portion. A jib foot pin is inserted into the jib foot pin insertion hole, and the jib foot pin prevents the boom top sheave shaft 52 from falling off from the jib foot portion 74.

The jib front portion 76 has a base jib 78 and a tip jib 84. The base jib 78 has a fixed jib 80 extending forward from the jib rear portion 70 and a movable jib 82 that can move in the front-rear direction with respect to the fixed jib 80. The base jib 78 has a jib undulating cylinder for moving the movable jib 82 inside the fixed jib 80, and the jib undulating cylinder is configured so that the movable jib 82 can be moved in the front-rear direction with respect to the fixed jib 80. ing.

The tip jib 84 is movable in the front-rear direction with respect to the movable jib 82. The front-back movement of the tip jib 84 is performed manually. At the tip of the tip jib 84, a jib top sheave 86 on which the supplementary winding wire rope 54B is hung is provided when the jib 30 is used.

The jib undulation mechanism 32 also includes two tension rods 90L and 90R provided in parallel. One end of each of the tension rods 90L and 90R is rotatably connected to the tip of the movable jib 82, and the other end is rotatably connected to the boom link 64 of the boom head 44 when the jib 30 is used. Rod.

Each of the tension rods 90L and 90R includes a tension rod main body 92 and an extension 94. One end of the extension 94 is pivotally supported by the tip of the movable jib 82, and is rotatably connected to the tip of the movable jib 82.

The extension 94 has a tubular shape, and a part of the tension rod main body 92 can be inserted. In other words, the tension rods 90L and 90R can be expanded and contracted.

The tension rods 90L and 90R can also be fixed to a predetermined length. Therefore, for example, the tension rod body 92 and the extension 94 are respectively formed with set pin insertion holes for inserting the tension rod set pins. The set pin insertion holes of the tension rod body 92 and the set pin insertion holes of the extension 94 are aligned, and the tension rod set pins are inserted into them, so that the tension rods 90L and 90R are fixed to a predetermined length.

The tension rod body 92 is configured to be connectable to the boom link 64. For example, the boom link 64 and the tension rod body 92 are respectively formed with connecting pin insertion holes into which the connecting pin 96 is inserted at their ends. The connecting pin insertion holes of the boom link 64 and the connecting pin insertion holes of the tension rod body 92 are aligned, and the connecting pins 96 are inserted into them, so that the tension rods 90L and 90R are connected to the boom link 64 by the connecting pins 96. It is rotatably connected.

As described above, the jib 30 is stored under the telescopic boom 24 in the lower hugging state. In the retracted state, the tension rods 90L and 90R are located below the jib 30 in the direction of gravity. Therefore, the jib undulation mechanism 32 includes two tension rod holding mechanisms 98 that support the two tension rods 90L and 90R, respectively, when the jib 30 is retracted. Each tension rod holding mechanism 98 is fixed to the jib 30.

Next, the overhanging of the jib 30 and the subsequent undulating motion of the jib 30 will be briefly described. Here, the overhang of the jib 30 means an operation until the jib 30 is moved from the retracted state to the start state of the undulating operation.

In the overhang of the jib 30, first, the jib foot portion 74 of the jib 30 is connected to the boom top sheave shaft 52 of the boom head 44. As a result, the jib 30 is rotatably connected to the boom head 44.

Next, the tension rod body 92 is pulled out from the extension 94, and the tension rod body 92 is connected to the boom link 64 of the boom head 44. As a result, the tension rods 90L and 90R are rotatably connected to the boom link 64. The tension rods 90L and 90R are released by releasing the holding by the tension rod holding mechanism 98.

Subsequently, after the telescopic boom 24 is raised upright, the telescopic boom 24 is extended by a predetermined length. As a result, the connection of the jib 30 to the telescopic boom 24 by the jib connection mechanism 34 is released, and the jib 30 hangs down in the direction of gravity. In other words, the jib 30 is supported in a substantially vertical position.

After that, the telescopic boom 24 is laid down to the extent that a worker on the ground can perform the next work on the jib undulating mechanism 32. During that time, the tension rods 90L and 90R can be expanded and contracted, and the angle of the jib 30 with respect to the expansion and contraction boom 24 can be changed.

Next, the set pin insertion holes of the tension rod body 92 and the extension 94 are aligned, and the tension rod set pins are inserted into them to fix the lengths of the tension rods 90L and 90R.

Subsequently, the telescopic boom 24 is erected. As the telescopic boom 24 stands up, the jib 30 projects forward. As a result, the overhang of the jib 30 is completed. When the overhang is completed, the jib 30 is in the start state of the subsequent undulating operation.

The jib 30 in the start state of the undulating motion is in the most laid-down state and is drawn on the lowermost side in FIG. Then, as the base jib 78 is extended, the jib 30 is erected. The most upright jib 30 is depicted on the uppermost side in FIG. On the contrary, as the base jib 78 is reduced, the jib 30 is laid down. That is, the jib 30 is undulated by expanding and contracting the base jib 78.

During the overhang of the jib 30, the pair of jib base ends 72L, 72R of the jib 30 pass on both sides of the main hook 62A. In other words, the main hook 62A passes between the pair of jib base ends 72L, 72R of the jib 30. It is the jib 30 that actually moves, but here, for convenience, it is expressed that the main hook 62A passes between the pair of jib base ends 72L, 72R of the jib 30.

When the main hook 62A passes between the pair of jib base ends 72L and 72R, there is a concern that the main hook 62A may come into contact with or collide with the tension rods 90L and 90R. Contact or collision between the main hook 62A and the tension rods 90L and 90R causes damage to the tension rods 90L and 90R. Therefore, it is desirable to avoid contact and collision between the main hook 62A and the tension rods 90L and 90R.

Therefore, as shown in FIG. 2, in the jib undulating mechanism 32, in order to avoid contact between the main hook 62A and the tension rods 90L and 90R, between the pair of jib base ends 72L and 72R between the overhangs of the jib 30. It has a protection mechanism 100 for preventing the main hook 62A passing through the rod from coming into direct contact with the tension rod 90L.

In this embodiment, the main hook 62A is turned somewhat clockwise when viewed from vertically above, due to the multiple turns of the main winding wire rope 54A around the boom top sheave 48A and the main hook 62A. Also, the jib 30 is slightly tilted toward the tension rod 90L. For this reason, that is, because of the rotation of the main hook 62A and the inclination of the jib 30, it is the tension rod 90L that is concerned about contact with the main hook 62A, and the tension rod 90R is concerned about contact with the main hook 62A. Less is. Therefore, the protection mechanism 100 is provided only on the tension rod 90L, and is not provided on the tension rod 90R.

Further, the jib undulation mechanism 32 has a receiving portion 182 that receives the protection mechanism 100. The receiving portion 182 is provided on the jib base end portion 72L.

Further, it has a protective plate 184 that prevents the main hook 62A passing between the pair of jib base end portions 72L and 72R during the overhang of the jib 30 from directly contacting the jib base end portion 72L. For the same reason as the tension rods 90L and 90R, it is the jib base end portion 72L that is concerned about contact with the main hook 62A, and the jib base end portion 72R is less concerned about contact with the main hook 62A. Therefore, the protective plate 184 is provided only on the jib base end portion 72L, and is not provided on the jib base end portion 72R.

Of course, the protection mechanism 100 may be provided on the tension rod 90R in addition to the tension rod 90L. Along with this, the receiving portion 182 and the protective plate 184 may also be provided on the jib base end portion 72R in addition to the jib base end portion 72L.

Next, the structure of the protection mechanism 100 will be described with reference to FIGS. 3 to 6. 3 and 4 are perspective views of the protection mechanism and the tension rod shown in FIG. In FIG. 3, the support structure and the guard member of the protection mechanism are disassembled and drawn. In FIG. 4, the assembled protection mechanism is depicted. FIG. 5 is a vertical cross-sectional view of the protection mechanism shown in FIG. 4 along the central axis of the tension rod. FIG. 6 is a cross-sectional view of the support structure along the line 13F-13F shown in FIG.

The protection mechanism 100 is a pair of support structures 120 that support the guard member 110 that covers at least the inner surface of the tension rod 90L and the guard member 110 with a gap formed between the tension rod 90L and the guard member 110. And have. Here, the inner surface of the tension rod 90L is the surface on the side facing the tension rod 90R. In other words, the inner surface of the tension rod 90L is a plane that passes through the central axis of the tension rod 90L and is parallel to the vertical direction, and when the tension rod 90L is virtually divided into two parts, the tension rod 90R It is a part of the outer peripheral surface of the part located on the side of.

The guard member 110 is made of metal, for example. The guard member 110 has a tubular shape. For example, the guard member 110 has a cylindrical shape, but is not limited to this. The tension rod 90L passes through the space inside the guard member 110. Therefore, the guard member 110 covers a part of the tension rod 90L over the entire circumference in the direction along the central axis.

The support structure 120 supports the guard member 110 so that the cylindrical guard member 110 is located at the same center as the tension rod 90L. Further, the support structure 120 is supported by the guard member 110 so that the guard member 110 can rotate freely. The rotation axis of the guard member 110 coincides with or substantially coincides with the central axis of the tension rod 90L.

The protection mechanism 100 is provided on the tension rod 90L near the jib base end portion 72L. That is, the support structure 120 supports the guard member 110 near the jib base end portion 72L.

Each support structure 120 has a pair of semi-cylindrical stoppers 130, a pair of semi-cylindrical spacers 150, and a double-sided tape 160 attached to a tension rod 90L.

The double-sided tape 160 functions to attach the spacer 150 to the tension rod 90L.

The spacer 150 is made of, for example, a resin, for example, nylon (registered trademark). The spacer 150 is fixed to the tension rod 90L by the double-sided tape 160. The pair of spacers 150 form a cylindrical shape when fixed to the tension rod 90L.

The stopper 130 is made of metal, for example. Each of the pair of stoppers 130 is fixed to the pair of spacers 150 by a pair of screws 172. The pair of stoppers 130 are also fixed to each other by a pair of screws 174. The pair of stoppers 130 form a cylindrical shape when fixed to each other.

As described above, each of the pair of stoppers 130 is fixed to the pair of spacers 150 by a pair of screws 172. Specifically, each stopper 130 has a screw hole 132 in the central portion, and each spacer 150 has a through hole 152 in the central portion. The through hole 152 has a diameter larger than that of the threaded portion of the screw 172. The screw hole 132 is composed of a stepped hole having a large diameter portion and a small diameter portion. The small diameter portion is located on the side facing the spacer 150, and the large diameter portion is located on the side facing the outside. The small diameter portion has a thread groove for screwing with the threaded portion of the screw 172. The large diameter portion has a diameter for inserting the screw head of the screw 172. Further, the large diameter portion has a depth such that the screw head of the screw 172 is completely buried when the screw 172 is completely screwed into the screw hole 132. That is, the screw head of the screw 172 does not protrude from the stopper 130. The pair of stoppers 130 are substantially positioned with each other by inserting a screw 172 screwed into each stopper 130 into a through hole 152 formed in each spacer 150.

As described above, the pair of stoppers 130 are fixed to each other by a pair of screws 174. Specifically, each stopper 130 has a through hole 134 at one end and a screw hole 136 at the other end. The through hole 134 and the screw hole 136 are formed so as to be aligned with each other when the pair of stoppers 130 form a cylindrical shape. The screw hole 136 has a screw groove for screwing with the screw portion of the screw 174. The through hole 134 is composed of a stepped hole having a large diameter portion and a small diameter portion. The small diameter portion is located on the side facing the screw hole 136 of the other stopper 130, and the large diameter portion is located on the side facing the outside. The small diameter portion has a diameter through which the screw portion of the screw 174 passes but does not allow the screw head to pass through. The large diameter portion has a diameter for inserting the screw head of the screw 174. Further, the large diameter portion has a depth such that the screw head of the screw 174 is completely buried in a state where the pair of stoppers 130 are fixed to each other by the screw 174. That is, the screw head of the screw 174 does not protrude from the stopper 130.

Each stopper 130 has a small diameter portion 142 and a large diameter portion 144 that are continuous with each other. The small diameter portion 142 is located on the side where the guard member 110 is located, and the large diameter portion 144 is located on the opposite side of the guard member 110. The large diameter portion 144 also has an edge portion 146 chamfered to have a roundness on the opposite side of the small diameter portion 142.

Hereinafter, it will be described assuming that the pair of stoppers 130 are fixed to each other. The small diameter portion 142 has a diameter slightly smaller than the inner diameter of the cylindrical guard member 110. Therefore, the small diameter portion 142 can be fitted to the guard member 110. The large diameter portion 144 has a diameter larger than the inner diameter of the guard member 110. Therefore, the large diameter portion 144 may come into contact with the end surface of the guard member 110 to restrict the movement of the guard member 110 along the central axis of the tension rod 90L. For example, the large diameter portion 144 has a diameter equal to the outer diameter of the guard member 110.

Each support structure 120 is attached to the tension rod 90L so that the small diameter portion 142 of the stopper 130 fits into the guard member 110. Preferably, each support structure 120 is attached to the tension rod 90L with some clearance between the large diameter portion 144 of the stopper 130 and the guard member 110. As a result, the cylindrical guard member 110 is supported by the pair of support structures 120 so as to be positioned at the same center as the tension rod 90L and freely rotate as described above.

As shown in FIG. 2 (see also FIGS. 9 to 12), the receiving portion 182 has a portion facing the protection mechanism 100 formed in an arc shape. Further, the receiving portion 182 is shaped so that the arcuate portion has a diameter equal to or slightly larger than the outer diameter of the cylindrical guard member 110 of the protection mechanism 100.

Further, the protective plate 184 is attached to the jib base end portion 72L in a state where a space is formed between the jib base end portion 72L and the protective plate 184 via a spacer (not shown).

Next, the operation when the main hook 62A comes into contact with or collides with the protection mechanism 100 will be described with reference to FIGS. 7 to 12. 7 and 8 are perspective views of the telescopic boom, the boom head, and the jib undulating mechanism shown in FIG. 2 as viewed from different directions, and show how the main hook contacts the protection mechanism. 9 and 10 are perspective views of the protection mechanism and its peripheral portion as viewed from different directions before the main hook and the protection mechanism come into contact with each other. 11 and 12 are perspective views of the protection mechanism and its peripheral portion as viewed from different directions after the contact between the main hook and the protection mechanism. 9 and 11 are perspective views viewed from the same direction, and FIGS. 10 and 12 are perspective views viewed from the same direction.

As long as the main hook 62A does not contact the protection mechanism 100, the tension rod 90L extends above the jib base end 72L along the jib base end 72L, as shown in FIGS. 9 and 10. .. Further, the tension rod 90L is separated from the jib base end portion 72L to the extent that the protection mechanism 100 is separated from the receiving portion 182.

As shown in FIGS. 7 and 8, when the main hook 62A comes into contact with the guard member 110 of the protection mechanism 100, the guard member 110 receives an impact from the main hook 62A. However, since the guard member 110 is supported by a pair of support structures 120 in a state where a space is formed between the tension rod 90L and the guard member 110, the impact received by the guard member 110 is the tension rod 90L. Is not directly transmitted to.

Further, since the guard member 110 is rotatably supported by the pair of support structures 120, the impact received by the guard member 110 is converted into the rotational movement of the guard member 110 and is suitably released.

In addition, the tension rod 90L may bend due to the impact received by the guard member 110. However, even in such a case, as shown in FIGS. 11 and 12, since the guard member 110 of the protection mechanism 100 is received by the receiving portion 182, it does not come into direct contact with the jib base end portion 72L. Absent.

Further, since the receiving portion 182 is formed in an arc shape having a diameter equal to or slightly larger than the outer diameter of the cylindrical guard member 110, the guard member 110 has arc-shaped surfaces on the receiving portion 182. Contact with. As a result, the force received by the guard member 110 from the receiving portion 182 is suppressed to be small. As a result, it is possible to prevent the guard member 110 from being undesirably greatly deformed.

Further, the main hook 62A may not come into contact with the protection mechanism 100 but may come into contact with the protection plate 184. When the main hook 62A comes into contact with the protective plate 184, the protective plate 184 receives an impact from the main hook 62A. However, the protective plate 184 is attached to the jib base end 72L with a spacer (not shown) forming a gap between the jib base end 72L and the protective plate 184. Therefore, the impact received by the protective plate 184 is not directly transmitted to the jib base end portion 72L.

Further, the main hook 62A may not come into contact with the protection mechanism 100, but the main winding wire rope 54A suspending the main hook 62A may come into contact with the protection mechanism 100. FIG. 13 is a perspective view of the telescopic boom 24, the boom head 44, and the jib undulating mechanism 32, and shows the main winding wire rope 54A in contact with the protection mechanism 100.

In that case, the main winding wire rope 54A often comes into contact with the end of the protection mechanism 100, as shown in FIG. As described above, the stopper 130 located at the end of the protection mechanism 100 has an edge portion 146 chamfered so as to have a rounded shape. Further, neither the screw 172 nor the screw 174 fixing the stopper 130 protrudes from the stopper 130. Therefore, when the main winding wire rope 54A comes into contact with the end portion of the protection mechanism 100, that is, the stopper 130, the pain suffered by the main winding wire rope 54A can be suppressed to a small extent.

[Second Embodiment]
A second embodiment will be described with reference to FIGS. 14 and 15. 14 and 15 are perspective views of the protection mechanism and the tension rod according to the second embodiment. FIG. 14 is a perspective view seen from the inside, and FIG. 15 is a perspective view seen from the outside.

As shown in FIGS. 14 and 15, in the protection mechanism 200 according to the present embodiment, a gap is formed between the guard member 210 that covers the inner surface of the tension rod 90L and the tension rod 90L and the guard member 210. It has a pair of support structures 220 that support the guard member 210 in this state.

The guard member 210 is made of metal, for example. The guard member 210 is composed of a strip-shaped plate member extending along the tension rod 90L. The guard member 210 is bent at a central portion extending parallel to the central axis of the tension rod 90L.

The support structure 220 supports the guard member 210 so that the bent portion of the guard member 210 is located inside the tension rod 90L.

The protection mechanism 200 is provided on the tension rod 90L near the jib base end portion 72L. That is, the support structure 220 supports the guard member 210 near the jib base end portion 72L.

Each support structure 220 has a spacer 230 fixed to the guard member 210 and a fixing member 240 fixing the spacer 230 to the tension rod 90L.

For example, both the spacer 230 and the fixing member 240 are made of metal. The fixing member 240 is fixed to the spacer 230 by a pair of screws 250. Specifically, the fixing member 240 has through holes 242 at both ends, and the spacer 230 has screw holes (not shown) at both ends. The screw hole has a screw groove for screwing with the screw portion of the screw 250.

When the main hook 62A comes into contact with the guard member 210 of the protection mechanism 200, the guard member 210 receives an impact from the main hook 62A. However, the guard member 210 is supported by a pair of support structures 220 in a state where a space is formed between the tension rod 90L and the guard member 210. Therefore, also in the present embodiment, as in the first embodiment, the impact received by the guard member 210 is not directly transmitted to the tension rod 90L.

Here, an example has been described in which the construction machine of the present embodiment is a crane vehicle that stores the jib 30 in a lower hugging state when not in use, but when the jib 30 is temporarily held in a lower hugging state and stored in a side hugging state when not in use. It may be a crane car to be stored in a crane.

Further, although the example in which the target to which the jib 30 is attached is the telescopic boom 24 has been described, the target to which the jib 30 is attached is not limited to the telescopic boom 24, and may be a non-expandable type boom.

The construction machine of the present embodiment is not limited to a crane vehicle, and may be a fixed crane. That is, the construction machine of the present embodiment may be a crane device including a telescopic boom and a jib. Furthermore, the construction machine of the present embodiment may be, in general, a crane device with a boom and a jib.

Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to these embodiments, and various modifications and modifications are made without departing from the gist thereof. May be good. The various modifications and changes referred to herein also include embodiments in which the above-described embodiments are appropriately combined.

10 ... Crane car, 12 ... Running body, 14 ... Wheels, 16 ... Out trigger, 18 ... Swivel body, 20 ... Swivel stand, 22 ... Driver's cab, 24 ... Telescopic boom, 26 ... Boom undulating device, 28 ... Boom undulating cylinder, 30 ... Jib, 32 ... Jib undulating mechanism, 34 ... Jib connecting mechanism, 36 ... Multi-stage boom, 44 ... Boom head, 46A ... Main winding guide sheave, 46B ... Supplementary winding guide sheave, 48A ... Boom top sheave, 48B ... Rooster top Sheave, 52 ... Boom top sheave shaft, 54A ... Main winding wire rope, 54B ... Supplementary winding wire rope, 62A ... Main hook, 62B ... Supplementary hook, 64 ... Boom link, 66 ... Shaft, 68 ... Boom link stopper, 70 ... Rear part of jib, 72L ... Jib base end, 72R ... Jib base end, 74 ... Jib foot part, 76 ... Jib front part, 78 ... Base jib, 80 ... Fixed jib, 82 ... Movable jib, 84 ... Tip jib, 86 ... Jib top sheave, 90L ... tension rod, 90R ... tension rod, 92 ... tension rod body, 94 ... extension, 96 ... connecting pin, 98 ... tension rod holding mechanism, 100 ... protection mechanism, 110 ... guard member, 120 ... support structure Body, 130 ... Stopper, 132 ... Screw hole, 134 ... Through hole, 136 ... Screw hole, 142 ... Small diameter part, 144 ... Large diameter part, 146 ... Edge part, 150 ... Spacer, 152 ... Through hole, 160 ... Double-sided tape , 172 ... Screw, 174 ... Screw, 182 ... Receiving part, 184 ... Protective plate, 200 ... Protective mechanism, 210 ... Guard member, 220 ... Support structure, 230 ... Spacer, 240 ... Fixing member, 242 ... Through hole, 250 …screw.

Claims (4)

The undulating boom and
A hook suspended from a boom head provided at the tip of the boom,
A jib rotatably connected to the boom to supplement the length of the boom,
It has a jib undulation mechanism that undulates the jib.
The jib has a pair of bifurcated jib base ends, the ends of the pair of jib base ends being rotatably connected to the boom head.
The jib undulation mechanism includes a pair of tension rods having one end connected to the jib and the other end connected to the boom head, and the hook passing between the pair of jib base ends between the overhangs of the jib. Has a protective mechanism that prevents the rod from coming into direct contact with the tension rod.
The protection mechanism has a guard member that covers at least the inner surface of the tension rod, and a support structure that supports the guard member in a state where a space is formed between the tension rod and the guard member. Is a construction machine. The guard member has a tubular shape, the tension rod passes through the space inside the guard member, and the guard member covers a part of the tension rod all around in a direction along a central axis. The construction machine according to claim 1, which covers the construction machine. The construction machine according to claim 2, wherein the support structure supports the guard member so that the guard member can rotate freely. The construction machine according to claim 3, wherein the rotation axis of the guard member coincides with the central axis of the tension rod.