JP7270799B2 - Boom device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom device that is mounted on a vehicle or the like and has a plurality of beams connected to each other so that it can be closed when stored and opened when used.

As a conventional boom device, for example, a “boom device for a concrete pump device” described in Patent Document 1 is known. Patent Literature 1 illustrates a link called a "boom link" in which two beams that are in a bending relationship are combined into one pair and one of the beams is sandwiched from the outside. This link is, for example, configured to form a pair of two plate-like bodies arranged so as to sandwich a beam, and is connected to a hydraulic cylinder that is driven when opening and closing a pair of beams. . Hereinafter, such a link configured as an outer link structure positioned outside the beam will be simply referred to as an "outer link".

By using such an outer link, there is no need to notch the beam to prevent interference with the link that moves when opening and closing, unlike when using an inner link that is positioned inside the width direction of the beam. Therefore, a decrease in beam intensity can be avoided.

Japanese Utility Model Publication No. 7-21728 (Figs. 1 and 2)

Here, there has been a demand for a configuration that can easily check beam damage (cracks, etc.) .

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a boom device that can easily check for beam damage (cracks, etc.) .

The present invention comprises a proximal beam and a distal beam pivotally connected to the proximal beam , one of the proximal beam or the distal beam being a boom closing beam. a receiving portion contacting a portion of the other of the proximal beam or the distal beam, the receiving portion contacting one of the proximal beam or the distal beam; The receiving part is detachably attached, and the receiving part has a hanging part facing the side part of the one beam, and the hanging part is detachably fixed to the side part via a fastening means. It is a boom device that

Still further, said one beam comprises a fastening seat for receiving said fastening means, said fastening seat being separate from said one beam and attached to a lateral portion of said one beam. The hanging portion can be detachably fixed to the fastening seat portion via the fastening means.

Further, the one beam has a flange protruding in the width direction from side portions positioned at both ends in the width direction of the beam, and the fastening seat portion has the width direction end as described above. Projecting outward from the brim portion, the receiving portion may include a base portion that abuts on the brim portion, and the hanging portion that is folded back from the base portion.

According to the present invention, beam damage (such as cracks) can be easily checked .

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows the concrete pump truck which mounts the boom apparatus which concerns on 1st Embodiment of this invention. It is a top view which shows the said concrete pump vehicle. FIG. 4 is a side view (illustrated in a sideways position) showing a state of extension of two beams on the tip end side of the boom device. FIG. 4 is a side view showing the entire boom device in a stored state; The outer link (tip side link) in the boom device is shown, (A) is a plan view, and (B) is a side view. FIG. 4 is a cross-sectional view showing the configuration of a receiving portion (a beam is indicated by a two-dot chain line) in the boom device according to the first embodiment of the present invention; FIG. 11 is a side view showing a state of the boom device and its surroundings around the link mechanism according to the second embodiment of the present invention when extended. FIG. 4 is a side view showing a main part of the boom device in a stored state; The outer link (tip side link) in the boom device is shown, (A) is a plan view, and (B) is a side view.

-First Embodiment-
Next, two embodiments in which the boom device 1 according to the present invention is applied to a concrete pump vehicle B will be described. First, the first embodiment will be described. Since the structure of the concrete pump car B is publicly known, the outline thereof will be described. As shown in FIGS. 1 and 2 (the vehicle body is indicated by a two-dot chain line), the concrete pump vehicle B has a boom 2, which is made by connecting a plurality of beams 3 to 3 in a bendable manner, to a vehicle body equipped with a chassis and the like. The vehicle is equipped with a boom 2 that can be extended by a hydraulic cylinder to cast ready-mixed concrete at a high place or in a remote place. The boom 2 closest to the base end (vehicle body side) is rotatable in the horizontal direction with respect to the vehicle body. 1 and 2 show a state in which the boom is closed with a plurality of beams folded, and the concrete pump vehicle B can travel on public roads. A concrete pumping pipe B1 is provided on the side of the boom 2 (part of which penetrates the boom 2 in the width direction). The ready-mixed concrete supplied from the concrete mixer truck is supplied to the hopper B2 located behind the vehicle, and the ready-mixed concrete in the hopper B2 is sent to the concrete pumping pipe B1 by the concrete pump provided on the vehicle body side. Then, ready-mixed concrete can be discharged from the tip opening of the concrete pumping pipe B1 arranged at the placement location.

As shown in FIG. 4, the boom 2 of this embodiment is constructed by connecting four beams 3 to 3 at three joints 21 to 21 so that the beams 3 to 3 can be alternately bent. Connections between adjacent beams 3, 3 are made at the ends of each beam 3. As shown in FIG. FIG. 3 shows the boom open state in which two of the four beams 3 to 3 on the tip side are extended. FIG. 4 shows the boom closed state in which the four beams 3-3 are folded. A link mechanism 4 is interposed between the adjacent beams 3, 3, and the link mechanism 4 is moved by a boom opening/closing cylinder 5 that expands and contracts by hydraulic pressure.

In this embodiment, the relationship between the two beams 3, 3 positioned first and second from the distal end side of the four beams 3 to 3 will be described. In the boom device 1 of the present embodiment, the beam 3 located on the proximal side of the two beams 3, 3 is referred to as the proximal side beam 3B. The movably connected beam 3 is referred to as a distal beam 3H. The terms "base end side" and "distal end side" are expressions based on relative positional relationships. Therefore, if the two beams 3 of interest change, the relationship between the "base end side" and the "tip end side" may also change. Between the proximal side beam 3B and the distal side beam 3H, as shown in FIG. 4, a link mechanism 4 is interposed in a portion that becomes inside when bent. The boom apparatus 1 of the present embodiment includes a boom opening/closing cylinder 5 that opens and closes the proximal side beam 3B and the distal side beam 3H by moving the link mechanism 4 .

At least one of the proximal side beam 3B and the distal side beam 3H has a curved portion 31 that is curved in a concave shape at a portion that is inside when the boom is closed. In this embodiment, as shown in FIG. 4, a curved portion 31 is formed in a portion of the distal beam 3H near the joint portion 21 . This curved portion 31 forms a space S between the proximal side beam 3B and the distal side beam 3H in the boom closed state.

The link mechanism 4 is rotatably connected to each of the proximal side beam 3B, the distal side beam 3H, and the boom opening/closing cylinder 5 . In this embodiment, they are rotatably connected by pins. The link mechanism 4 has a proximal link 4B and a distal link 4H. The base end link 4B is an inner link that is positioned inside the base end beam 3B in the width direction. As shown in FIG. 3, the proximal link 4B of this embodiment is a link that is curved in a substantially U shape when viewed from the side. On the other hand, the distal link 4H is an outer link 41 arranged to sandwich the proximal beam 3B or the distal beam 3H from the outside in the width direction. The distal link 4H of the present embodiment is a substantially straight rod-shaped link provided between the proximal link 4B and the distal beam 3H. The "width direction" is the horizontal direction when each beam 3 is viewed in the extending direction, and corresponds to the direction perpendicular to the paper surface in FIGS.

The boom opening/closing cylinder 5 is configured such that the cylinder rod 52 protrudes and retracts with respect to the cylinder tube 51 . The cylinder tube 51 side is rotatably connected to the proximal end beam 3B, and the cylinder rod 52 side is rotatably connected to the link mechanism 4 .

In this embodiment, as shown in FIGS. 5A and 5B, the front end link 4H, which is the outer link 41, includes a pair of plate-like portions 411 and 411 facing each other in the width direction, and a pair of plate-like portions 411 and 411 facing each other in the width direction. and a connecting portion 412 that connects the portions 411 , 411 . The connecting portion 412 is a tubular body. A round pipe is used for the connecting portion 412 of the present embodiment, and is fixed by welding to each of the opposing surfaces of the pair of plate-like portions 411 , 411 . In this embodiment, a connecting plate 413 is provided adjacent to the base end link 4B side of the connecting portion 412 , and this connecting plate 413 also connects the pair of plate-like portions 411 , 411 . In addition, each plate-like portion 411 has through holes 414, 414 at both ends in the longitudinal direction through which pins for axially connecting the proximal link 4B and the distal end beam 3H pass. Specifically, the through hole 414A is through which the pin for axially connecting the base end side link 4B penetrates, and the through hole 414A is through which the pin for axially connecting the distal side beam 3H penetrates. 414B. That is, the tip-side link 4H includes two shaft support portions (positions on the inner surfaces of the through holes 414A and 414B) that are supported by pin connections, and a pair of plate-like portions 411 between the two shaft support portions. , 411, and a connecting portion 412 for connecting the . A portion of the links that are pivotally supported by pin connection also corresponds to the pivotal support portion.

Here, the phrase "between the two pivots" means between the through hole 414A connecting the proximal link 4B with a pin and the through hole 414B connecting the distal end beam 3H with a pin (1 It is not between the through holes 414A, 414A or between the through holes 414B, 414B formed facing the pair of plate-like portions 411, 411). As the position where the connecting portion 412 is provided, it is preferable that the “between the two pivot portions” be between the axis passing through one through hole 414 and the axis passing through the other through hole 414 (specifically, each plate-like portion 411 is an area between two lines that are perpendicular to a line connecting the axes of the axes and a line that coincides with the axes of the axes when viewed from the front. At least a portion of the connecting portion 412 is positioned between the and the shaft. More preferably, the entire connecting portion 412 is positioned between the shafts. If all of them are positioned in this manner, the entire connecting portion 412 exists between the shafts, which are the sections through which the driving force is transmitted in the outer link 41. available for the transmission of waste-free.

In this embodiment, the pair of plate-like portions 411, 411 are connected in the width direction by the connecting portion 412, so that the tip end side link 4H is integrated (at least, the connecting portion 412 connects the pair of plate-like portions 411, 411). Large displacement of the shaped portions 411, 411 is suppressed). Therefore, the driving force associated with the expansion and contraction of the boom opening/closing cylinder 5 tends to be evenly applied to each of the pair of plate-like portions 411 , 411 of the outer link 41 . Further, even if the driving force is applied, the gap between the pair of plate-like portions 411, 411 is less likely to change. Therefore, it is possible to suppress the tip-side beam 3H from swaying in the width direction with respect to the base-side beam 3B. Therefore, it is possible to effectively prevent the deviation of the pair of plate-like portions 411 from shifting the center of gravity of the vehicle and possibly causing the vehicle to overturn, which has been a conventional problem. . This effect is most preferably obtained in a configuration in which the boom opening/closing cylinder 5 is directly connected to the outer link 41 provided with the connecting portion 412, as in the second embodiment described later. However, even if the driving force of the boom opening/closing cylinder 5 acts indirectly on the outer link 41 having the connecting portion 412 as in the present embodiment, good results can be expected. Note that the connecting portion 412 can also connect the pair of plate-like portions 411 , 411 at a fixed interval in the width direction. By doing so, the transmission of the driving force by the pair of plate-like portions 411, 411 is ensured compared to a configuration in which the distance changes.

In addition, the connecting portion 412 is such that the locus of movement of the connecting portion 412 accompanying the opening and closing of the proximal side beam 3B and the distal side beam 3H is curved in the concave shape between the proximal side beam 3B and the distal side beam 3H. It is located in the space S formed by the curved portion 31 formed by the curved portion 31 . In this way, by arranging the connecting portion 412 so as to move within the space S set between the beams 3B and 3H, interference with the connecting portion 412 of the outer link 41 can be avoided. Alternatively, there is no need to notch the tip side beam 3H. Therefore, it is possible to suppress a decrease in strength of the proximal side beam 3B or the distal side beam 3H (the distal side beam 3H in this embodiment).

One of the proximal side beam 3B or the distal side beam 3H is provided with a receiving portion 7 that contacts a portion of the other of the proximal side beam 3B or the distal side beam 3H facing each other in the boom closed state. The receiving portion 7 is provided to prevent the beam 3 from shifting in the width direction while the vehicle is running, and is detachably attached to the proximal side beam 3B or the distal side beam 3H. In this embodiment, as shown in FIG. 4, the distal end beam 3H is provided with a receiving portion 7, and the protruding portion 3B1 formed on the proximal end beam 3B is configured to contact the receiving portion 7 when the boom is closed. there is However, without being limited to this combination, the beam 3 on the side provided with the receiving portion 7 and the beam 3 on the side contacting the receiving portion 7 can have various configurations.

The receiving portion 7 of this embodiment will be specifically described. As shown in FIG. 6, of the proximal side beam 3B or the distal side beam 3H, the beam 3 to which the receiving portion 7 is attached extends in the width direction from side portions 32 positioned at both ends of the beam 3 in the width direction. It has a protruding flange portion 33 and a fastening seat portion 34 at a position spaced downward in the drawing from the flange portion 33 in the side portion 32 . The fastening seat portion 34 is a separate member from the proximal side beam 3B, is attached to the side portion 32, and has an end portion in the width direction protruding outside the flange portion 33. As shown in FIG. The fastening seat portion 34 of this embodiment is a tubular body having a threaded inner peripheral surface and is attached to the side portion 32 by welding.

The receiving portion 7 includes a base portion 71 that abuts on the flange portion 33 of the beam 3 to which the receiving portion 7 is attached, a hanging portion 72 that is folded back from the base portion 71, and the side of the base portion 71 opposite to the beam 3 (upper side in the drawing). and a receptacle 73 attached to the . The hanging portion 72 is detachably fixed by screwing a bolt 74 into the fastening seat portion 34 . For this reason, a through hole 75 through which the bolt 74 passes is formed in the hanging portion 72 . The receptacle part 73 of this embodiment is fixed to the base part 71 by welding. can insert part of

By providing the receiving portion 7 configured in this manner, the receiving portion 7 can be removed from the beam 3 to which the receiving portion 7 is attached, as compared with the case where the receiving portion 7 is non-removably attached by welding or the like. It is preferable because it is possible to check for damage (cracks, etc.) of 3.

Furthermore, since the receiving portion 7 can be fixed without providing a portion for bolting, such as a bolt hole, directly to the beam 3, a decrease in the strength of the beam 3 can be suppressed. Moreover, since the fastening seat portion 34 protrudes in the width direction from the side portion 32 of the beam 3 , when attaching the receiving portion 7 to the beam 3 , the hanging portion 72 is excessively curved (the hanging portion 72 is bent with respect to the base portion 71 ). Since there is no need to bend it at an acute angle, etc., the receiving part 7 can be easily fixed.

-Second Embodiment-
Next, a second embodiment will be described. The boom 2 of this embodiment has a form as shown in FIGS. 7 and 8. FIG. Also in the boom device 1 of the present embodiment, the beam 3 located on the proximal side of the two beams 3, 3 is referred to as the proximal side beam 3B, and is rotatably connected to the proximal side beam 3B. The beam 3 thus obtained is referred to as a tip-side beam 3H. In the present embodiment, a link mechanism 4 is interposed between the proximal side beam 3B and the distal side beam 3H in a portion that becomes the outer side (inside and outside directions are opposite to those in the first embodiment) when bent.

The proximal side beam 3B and the distal side beam 3H are rotatably connected by a beam connecting shaft 3S. One end (the base end of the cylinder tube 51 in this embodiment) of the boom opening/closing cylinder 5 is a portion of the base end beam 3B that is opposite (bottom in the vertical direction) the tip end beam 3H when the boom is closed. , and the other end (the tip of the cylinder rod 52 in this embodiment) is pin-connected to the outer link 41 . Since the end of the base end beam 3B and the end of the tip end side beam 3H of the beam-to-beam connecting shaft 3S slide as they rotate, the side surfaces of the beam connecting shaft 3S are coated with oil such as grease to reduce friction. .

The link mechanism 4 of this embodiment includes a distal end side link 4H as the outer link 41. As shown in FIG. A secondary link 42 that connects one of the proximal side beam 3B and the distal side beam 3H is further provided. The base end link 4B of this embodiment functions as the secondary link 42 and connects the tip end link 4H and the base end beam 3B. The proximal link 4B of the present embodiment is an outer link 41 because it is arranged to sandwich the proximal beam 3B from the outside in the width direction. However, the secondary link 42 may be an inner link. The tip-side link 4H includes a pair of plate-like portions 411, 411 facing each other in the width direction, and a connecting portion 412 connecting the pair of plate-like portions 411, 411, as in the first embodiment. The connecting portion 412 is composed of a tubular body passing through the plate-like portions 411 , 411 . Further, each plate-like portion 411 has through holes 414, 414 through which the pins 61, 62 pass through at both ends in the longitudinal direction. Specifically, the first pin 61 for axially connecting the boom opening/closing cylinder 5 passes through the through hole 414C, and the second pin 62 for axially connecting the tip side beam 3H. passes through the through hole 414D.

The tip side link 4H is connected to the boom opening/closing cylinder 5 via a first pin 61 and a through hole 414C, and is connected to the tip side beam 3H via a second pin 62 and a through hole 414D, It is connected via a third pin 63 to the proximal link 4B. The third pin 63 is supported by a tubular boss 64 (see FIGS. 9A and 9B). In the present embodiment, this boss 64 also serves as a connecting portion 412 that integrates the tip side link 4H. Therefore, the number of component parts of the boom device 1 can be reduced. As in the first embodiment, the front end link 4H of this embodiment also has two shaft support portions (positions of the pins 61 and 62) that are supported by pin connections, and a pair of shaft support portions between the two shaft support portions. and a connecting portion 412 that connects the plate-like portions 411 and 411 of the .

As shown in FIG. 4B, the tip side link 4H is arranged outside in the width direction with respect to the beam connecting shaft 3S in the boom closed state. A through-hole 415 is formed in each plate-like portion of the tip-side link 4H at a position corresponding to the beam-to-beam connecting shaft 3S when the boom is closed. As shown in FIG. 5B, the through hole 415 penetrates each plate-like portion 411 in the thickness direction. By forming the through hole 415 in each plate-like portion in this way, the weight of the tip side link 4H can be reduced. Furthermore, as shown in FIG. 8, even when the boom is closed, at least a part of the end of the beam connecting shaft 3S is exposed from the through hole 415, so that the beam connecting shaft 3S can be lubricated through the through hole 415. . That is, the through hole 415 of this embodiment functions as a grease supply hole for the beam connecting shaft 3S.

-About change of embodiment-
As described above, two embodiments of the present invention have been described, but the present invention is not limited to these embodiments. For example, the application target of the boom device 1 according to the present invention is not limited to the concrete pump vehicle of the above-described embodiment, and may be other types of vehicles, or may be a stationary device that is used without being moved. good.

Also, the cross-sectional shape of the beam 3 is not limited to that of the above embodiment. For example, the flange portion 33 may be omitted, or another form such as a form in which the flange portion protrudes vertically may be used.

Also, the outer link 41 may be applied to any of the plurality of beams 3 . Further, in the first embodiment, the tip-side link 4H is the outer link 41, which is arranged so as to sandwich the tip-side beam 3H from the outside in the width direction. However, the present invention is not limited to this, and the base end link 4B in the first embodiment may be replaced with the outer link 41 and arranged so as to sandwich the base end beam 3B from the outside in the width direction. Furthermore, as in the second embodiment, both the distal link 4H and the proximal link 4B (secondary link 42 in the above embodiment) can be the outer link 41. FIG. Conversely, the secondary link 42 in the second embodiment can also be changed to an inner link.

Further, the pivotal support portion may be a portion that is pivotally supported by a pin connection to the base end beam 3B or the boom opening/closing cylinder 5, for example.

Moreover, the connecting part 412 is not limited to the tubular body as in the above embodiment, and may be a solid rod-shaped body or a plate-shaped body. Further, the cross-sectional shape of the tubular body or rod-shaped body is not limited to circular as in the present embodiment, but may be polygonal. Moreover, the connection part 412 can also be made into a plate-shaped body.

Further, the connecting portion 412 is not limited to the form of being fixed (immovable) to the pair of plate-like portions 411, 411 by welding or the like as in the above-described embodiment. can be connected, the connecting portion 412 can be moved with respect to the pair of plate-like portions 411, 411 (for example, can be rotated or slid with respect to the plate-like portion 411). That is, the connection by the connecting portion 412 is generated in the two plate-like portions 411, 411 even when the driving force of the boom opening/closing cylinder 5 is biasedly transmitted to one of the two plate-like portions 411, 411. It is sufficient if it is done to the extent that the difference in behavior can be suppressed.

Further, in the second embodiment, the boss 64 that supports the third pin 63 is configured to also serve as the connecting portion 412 . However, the configuration is not limited to this, and the third pin 63 itself may also serve as the connecting portion 412 . In this way, a part of the connecting mechanism (mechanism to which the third pin 63 belongs) that rotatably connects the outer link 41 (the tip side link 4H in the second embodiment) and the sub link 42 is the connecting portion. 412.

Moreover, the receiving part 7 is not limited to the bolt 74 as in the above embodiment, and may be attached to the beam 3 by various fastening means.

Here, in the configuration described in Patent Document 1, the distance between the two plate-like members that form the outer link is larger than that of the inner link because they are located outside the beam. In that case, when the driving force of the hydraulic cylinder is biased to one of the two plate-shaped bodies when opening and closing, the other will be left behind, resulting in a difference in the behavior of the two plate-shaped bodies. easier. Due to this difference, when the boom is extended, the leading beam in the set of beams will be displaced in the width direction. In the case of a boom device mounted on a vehicle, this deviation changes the center of gravity of the vehicle because the deviation becomes more pronounced as the distance between the joints where the two beams are connected increases. In some cases, it may also cause the vehicle to overturn.

Therefore, it is an object of the invention to provide a boom device that can suppress the beam from shifting in the width direction when opening and closing even when an outer link is used.

In response to the above problem, a proximal side beam, a distal side beam rotatably connected to the proximal side beam, and a link mechanism interposed between the proximal side beam and the distal side beam and a boom opening/closing cylinder that opens and closes the proximal side beam and the distal side beam by moving the link mechanism, wherein the link mechanism moves the proximal side beam or the distal side beam. It has outer links arranged so as to sandwich from the outside of the direction, and is rotatably connected to each of the base end side beam, the tip side beam, and the boom opening/closing cylinder at a pivot portion, and the boom opening/closing is performed. A cylinder is rotatably connected to each of the base-end beam and the link mechanism, and the outer link includes the two shaft support portions, a pair of plate-shaped portions facing each other in the width direction, and the and a connecting portion that connects the pair of plate-like portions between two pivot portions.

According to the above configuration, since the pair of plate-like portions are connected by the connecting portion between the two shaft support portions of the outer link, the driving force from the boom opening/closing cylinder is applied to the pair of plate-like portions of the outer link. It is easy to join each part evenly. Therefore, it is possible to suppress the tip-side beam from blurring in the width direction with respect to the base-side beam.

Further, the link mechanism further includes a sub-link that connects the outer link and one of the proximal side beam and the distal side beam, and the outer link is connected to the boom opening/closing cylinder as a secondary link. connected via one pin, connected to the other of the proximal beam or the distal beam via a second pin, and connected to the secondary link via a third pin. and a connecting mechanism for rotatably connecting the outer link and the sub-link, wherein a part of the connecting mechanism to which the third pin belongs also serves as the connecting portion.

With this configuration, the number of components can be reduced.

Furthermore, the proximal side beam and the distal side beam are connected by a beam connecting shaft, and one end of the boom opening/closing cylinder is connected to the distal side beam in the boom closed state on the proximal side beam. The other end is pin-connected to the outer link, the outer link is pin-connected to the tip side beam, and the beam-to-beam connecting shaft is connected when the boom is closed. , and a through hole can be formed at a position corresponding to the beam connecting shaft in the boom closed state.

According to this configuration, the outer link can be made lighter by forming the through hole in the outer link. Furthermore, even when the boom is closed, at least a part of the end of the beam connecting shaft is exposed through the through hole, so that the beam connecting shaft can be lubricated through the through hole.

Furthermore, at least one of the proximal side beam and the distal side beam is formed with a curved portion in which a portion that becomes an inner side when the boom is closed is concavely curved, and the connection portion is formed between the proximal side beam and the distal side beam. A locus of movement of the connecting portion accompanying opening and closing with the distal beam may be located in a space formed by the curved portion between the proximal beam and the distal beam.

According to this configuration, it is not necessary to notch the proximal side beam or the distal side beam in order to avoid interference with the connecting portion provided in the outer link, so it is possible to suppress a decrease in the strength of the proximal side beam or the distal side beam.

Further, one of the proximal side beam and the distal side beam includes a receiving portion that contacts a portion of the other of the proximal side beam and the distal side beam that face each other in the boom closed state, The receiver may be detachably attached to one of the proximal beam and the distal beam.

According to this configuration, the receiving portion can be removed from the beam to which it is attached, so that the beam can be checked for damage (cracks, etc.).

Furthermore, of the proximal side beam or the distal side beam, the beam to which the receiving portion is attached has a flange protruding in the width direction from the side portions located at both ends in the width direction of the beam. and a fastening seat spaced apart from the collar on the lateral portion, the fastening seat being separate from the beam and attached to the lateral portion and extending across the width of the beam. A direction end protrudes outward from the flange portion, and the receiving portion includes a base portion that abuts on the flange portion and a hanging portion that is folded back from the base portion, and the hanging portion extends from the fastening seat portion. It can be detachably fixed to the via a fastening means.

According to this configuration, the receiving portion can be fixed directly to the beam without providing a portion for fastening means such as a bolt hole, so that a decrease in the strength of the beam can be suppressed. In addition, since the fastening seat protrudes in the width direction from the side portion of the beam, it is not necessary to bend the hanging portion excessively, so that the receiving portion can be easily fixed.

According to the above configuration, it is possible to suppress the tip-side beam from blurring in the width direction with respect to the base-side beam. Therefore, even when the outer link is used, it is possible to prevent the beam from shifting in the width direction when opening and closing.

1 boom device 2 boom 3 beam 3B proximal side beam 3H distal side beam 3S beam connecting shaft 31 bending section 32 side section 33 collar section 34 fastening seat section 4 link mechanism 4B proximal side link 4H distal side link 41 outer link 411 Plate-like part (outer link)
412 Connection part (outer link)
415 through hole 42 secondary link 43 coupling mechanism 5 boom opening/closing cylinder 61 first pin 62 second pin 63 third pin 7 receiving portion 71 base portion 72 hanging portion
73 receiver
74 fastening means, bolts
S space

Claims (3)

a proximal beam;
a distal beam rotatably connected to the proximal beam;
one of the proximal side beam and the distal side beam includes a receiving portion that contacts a part of the other of the proximal side beam and the distal side beam that faces each other in the boom closed state;
The receiving part is detachably attached to one of the proximal side beam and the distal side beam,
the receiving part has a hanging part facing the side part of the one beam,
The boom device, wherein the hanging portion is detachably fixed to the side portion via fastening means. said one beam comprising a fastening seat for receiving said fastening means;
The fastening seat is separate from the one beam and attached to a lateral portion of the one beam,
The boom apparatus according to claim 1, wherein the hanging portion is detachably fixed to the fastening seat portion via the fastening means. said one beam has a flange protruding in said width direction from side portions positioned at both ends in said width direction of said beam;
The fastening seat portion has an end portion in the width direction that protrudes outward from the flange portion,
3. The boom device according to claim 2, wherein the receiving portion includes a base portion that abuts on the flange portion, and the hanging portion that is folded back from the base portion.

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