JP2012017181A - Latticed boom - Google Patents

Abstract

[PROBLEMS] To reduce lateral deflection that occurs in a lattice boom during crane work while avoiding a significant increase in weight and lateral width of the lattice boom.
A lower boom 2 of a lattice boom 1 is connected to a front end portion of a right front main pipe 20a on a right side surface thereof, and is formed between a right front main pipe 20a and a right rear main pipe 20b toward the right foot portion 12a. The right front diagonal member 32 extending so as to gradually approach the intermediate position between the right front main pipe 20b and the right front main pipe 20b. The right rear diagonal member 34 extending so as to gradually approach an intermediate position between the right front diagonal member 32 and the right end portion of the right front diagonal member 32 and the right end portion of the right rear diagonal member 34 and the right foot portion 12a. And a left front diagonal member 42, a left rear diagonal member 44, and a left connecting member 46 configured in the same manner as the right front diagonal member 32, the right rear diagonal member 34, and the right connecting member 36 on the left side surface.
[Selection] Figure 2

Description

  The present invention relates to a lattice boom provided in a crane.

  2. Description of the Related Art Conventionally, a lattice boom is known which is provided on a crane so as to be raised and lowered and has a lattice structure. The following Patent Document 1 discloses a crane having a lattice boom, and the lattice boom provided on the crane is a main pipe disposed at a position corresponding to each vertex of a quadrangle in a cross section perpendicular to the longitudinal direction. And a plurality of diagonal members that connect adjacent main pipes to form a lattice structure. In addition, the crane includes an upper swing body that can swing around a vertical axis, and the upper swing body is provided with a lattice boom. In this crane, the crane work is performed by lifting or lowering the lattice boom or turning the upper swing body while the suspended load is suspended from the tip of the lattice boom. In addition, the two main pipes are respectively arranged on one side face of the lattice boom facing the turning direction of the upper turning body and on the opposite side face thereof. The two main pipes located on each side surface are connected in a zigzag manner by a plurality of diagonal members arranged between them.

JP-A-9-255283

  When crane work is performed on the crane as described above, when the suspended load suspended from the tip of the lattice boom receives a crosswind or when the ground is inclined in the lateral direction of the crane body, When the turning of the upper-part turning body is accelerated or decelerated, a lateral bending load acts on the lattice boom. When such a bending load in the lateral direction is applied, the lattice boom is bent in the lateral direction. For the bending in the lateral direction of the lattice boom, for example, a load corresponding to 2% of the suspension load is applied in the horizontal direction. When given laterally, there is a limitation by the standard that the amount of lateral deflection of the lattice boom is less than 2% of the length of the lattice boom. For these reasons, reducing the lateral deflection of the lattice boom is an important issue.

  Various methods have been studied in order to suppress the lateral deflection that occurs in the lattice boom during crane work, but all have various problems.

  For example, in the method of increasing the lateral bending rigidity of the lattice boom by suppressing the lateral bending by configuring the lattice boom with a main pipe having a large cross-sectional area, the self-weight of the lattice boom is significantly increased. As a result, there arises a problem that the suspension capacity of the crane is lowered. Specifically, since the position of the center of gravity of the lattice boom is far from the main body of the crane, the crane is likely to fall when the weight of the lattice boom increases. For this reason, the maximum weight of the suspended load which can be hung in the range which can avoid the fall of a crane safely falls, so that the own weight of a lattice boom becomes large. For this reason, even when trying to suppress the lateral deflection of the lattice boom, a significant increase in the weight of the boom should be avoided.

  In addition, it is conceivable to increase the lateral width of the lattice boom to suppress lateral deflection that occurs in the lattice boom during crane operation, but considering the transportability of the lattice boom, it is practically difficult to increase the width of the lattice boom. It is. Specifically, if the width of the lattice boom exceeds the range that fits within the width of the trailer for transportation, it will be necessary to submit an application at the time of transportation, or the transportation route will be restricted. The movement of the crane to the side becomes complicated or difficult. Therefore, even when it is intended to suppress the lateral deflection of the lattice boom, it is necessary to avoid an increase in the width of the lattice boom.

  The present invention has been made in order to solve the above-mentioned problems, and its object is to avoid lateral deflection that occurs in the lattice boom during crane operation while avoiding a significant increase in the weight and lateral width of the lattice boom. It is to reduce.

  In order to achieve the above object, a lattice boom according to the present invention is a lattice boom that is attached to a swingable upper swing body of a crane that can be swung freely, and a suspended load is suspended from a tip portion thereof. A lower boom that is attached to the body, and an upper boom that is connected to a distal end side of the lower boom. The lower boom includes a boom foot that is attached to the upper swing body, and a distal end side of the lower boom from the boom foot. A lower boom body having a plurality of main pipes, each of which is disposed at a position corresponding to each vertex of a quadrangle in a cross section perpendicular to the longitudinal direction of the lower boom, and is connected to the boom foot; A plurality of sub-materials disposed between adjacent main pipes, and the plurality of main pipes include the lower boot. A first main pipe and a second main pipe which are spaced apart from each other on a first side surface facing the turning direction of the upper swing body, and a first side surface of the lower boom opposite to the first side surface. A third main pipe and a fourth main pipe that are spaced apart from each other on the two side surfaces; and the plurality of sub-materials include a tip of the first main pipe on the first side surface. A first diagonal member that extends so as to gradually approach an intermediate position between the first main pipe and the second main pipe as it goes toward the boom foot side, and on the first side surface, the second A second diagonal member connected to the leading end of the main pipe and extending gradually toward an intermediate position between the first main pipe and the second main pipe toward the boom foot side, and the first side surface In the above, the base end of the first diagonal member and The second diagonal member is connected to a base end portion of the lower oblique body and a portion of the lower boom body that is located closer to the boom foot than the base end portion of the first diagonal member and the base end portion of the second diagonal member. 1 connecting material and on the second side surface, connected to the tip of the third main pipe, and gradually toward an intermediate position between the third main pipe and the fourth main pipe toward the boom foot side A third diagonal member extending so as to approach, and on the second side surface, is connected to a tip end portion of the fourth main pipe and between the third main pipe and the fourth main pipe toward the boom foot side. A fourth diagonal member extending so as to gradually approach an intermediate position, and a base end portion of the third diagonal member and a base end portion of the fourth diagonal member and the lower boom body on the second side surface. More than the base end of the third diagonal and the base end of the fourth diagonal And a second connecting member that connects a portion located near the boom foot.

  In this lattice boom, since a compressive load generated on either side when a lateral bending load is applied to the lattice boom is smoothly transmitted to a rigid upper swing body, the lateral direction generated in the lattice boom during crane operation Deflection is reduced. For example, the first main pipe and the second main pipe located on the first side surface of the lower boom due to the bending load are subjected to a compressive load in the longitudinal direction and the third main pipe located on the second side surface. When a tensile load in the longitudinal direction acts on the fourth main pipe, the compressive load acting on the first main pipe and the second main pipe is smoothly transmitted to the upper swing body. More specifically, when the lateral bending load is applied to the lattice boom, the compressive load acting on the first main pipe is the first of the lower boom bodies via the first diagonal member and the first connecting member. The compressive load acting on the second main pipe is transmitted to the part located near the boom foot on the side surface, and close to the boom foot on the first side surface of the lower boom body via the second diagonal member and the first connecting member. It is transmitted to the site where it is located. That is, in this lattice boom, as compared with the conventional structure in which main pipes adjacent on the side surface of the lower boom are connected in a zigzag manner with a plurality of diagonal members, the compressive load acting on both the main pipes is reduced. The lower boom body can be directly transmitted to the part near the boom foot via the diagonal member and the first connecting member, and as a result, the compressive load acting on the two main pipes can be smoothly transferred to the upper swing body side. Can communicate. Similarly, a longitudinal compressive load acts on the third main pipe and the fourth main pipe located on the second side surface of the lower boom due to a lateral bending load applied to the lattice boom, and on the first side surface. In the case where a tensile load in the longitudinal direction acts on the first main pipe and the second main pipe located at, the third diagonal member, the fourth diagonal member and the second connecting member are the first diagonal member and the second diagonal member. Compressive load acting on the third main pipe and the fourth main pipe functions smoothly to the upper swing body side, functioning similarly to the material and the first connecting material. From the above, in this lattice boom, when a bending load in the lateral direction is applied, a compressive load acting on the main pipe located on the first side surface or the second side surface of the lower boom is subjected to the main pipe and the diagonal material. The connecting material smoothly transmits to the upper swing body side, and the bending deformation of the lower boom in the lateral direction is suppressed. As a result, the lateral bending of the lattice boom that occurs during the crane operation is reduced.

  Moreover, since the bending of the lattice boom in the lateral direction can be reduced by devising the arrangement of the secondary material in this way, it is possible to eliminate the need to increase the wall thickness and diameter of the main pipe in order to suppress the bending. Or the need can be reduced. As a result, it is possible to suppress the lateral deflection of the lattice boom while avoiding a significant increase in the weight of the lattice boom.

  Further, for the same reason, the lateral deflection of the lattice boom can be reduced without significantly increasing the lateral width of the lattice boom.

  In the lattice boom, the boom foot is located on the first side surface, and is coupled to the proximal end portion of the first main pipe and the proximal end portion of the second main pipe, and the second foot. A second foot portion located on a side surface and coupled to a base end portion of the third main pipe and a base end portion of the fourth main pipe; and the first connecting member is the first diagonal member And a first coupling portion coupled to the proximal end portion of the second diagonal member, extending along a center line between the first main pipe and the second main pipe, and the first coupling portion And a first central connecting member that connects the first foot portion, and the second connecting member is a second member that is coupled to the base end portion of the third diagonal member and the base end portion of the fourth diagonal member. A coupling portion extends along a center line between the third main pipe and the fourth main pipe, and connects the second coupling portion and the second foot portion. It may include a second central connecting member.

  According to this configuration, when a lateral bending load is applied to the lattice boom and a compressive load is applied to the first main pipe and the second main pipe, the compression transmitted from the first main pipe to the first diagonal member. The load and the compressive load transmitted from the second main pipe to the second diagonal member are directly transmitted to the first foot portion through the first coupling portion and the first central connecting member, while being transmitted to the third main pipe and the fourth main pipe. When a compressive load is applied, the compressive load transmitted from the third main pipe to the third diagonal member and the compressive load transmitted from the fourth main pipe to the fourth diagonal member are connected to the second coupling portion and the second center connection. It is transmitted directly to the second foot through the material. For this reason, the compressive load which acts on each main pipe resulting from the bending load to the said horizontal direction can be transmitted more smoothly to the upper turning body side.

  In the lattice boom, the first connecting member is connected to a base end portion of the first diagonal member and a base end portion of the second diagonal member, and from the first connecting portion to the boom foot side. As it goes, it extends so as to gradually approach the first main pipe, and connects the first coupling portion and a portion of the first main pipe that is located closer to the boom foot than the first coupling portion. The slanted connecting member and the first connecting portion extending from the first connecting portion toward the boom foot side so as to gradually approach the second main pipe, and the first connecting portion out of the first connecting portion and the second main pipe. A second diagonal connecting member that connects a portion located closer to the boom foot than the second diagonal connecting member, and the second connecting member is connected to a base end portion of the third diagonal member and a base end portion of the fourth diagonal member. A second coupling portion to be coupled, and the second coupling portion from the second coupling portion. Extending gradually toward the third main pipe as it goes to the foot side, connecting the second coupling part and a portion of the third main pipe located closer to the boom foot than the second coupling part A third diagonal connecting member that extends from the second coupling portion toward the boom foot side so as to gradually approach the fourth main pipe, and the second coupling portion and the fourth main pipe out of the second coupling portion. The 4th diagonal connection material which connects the site | part located near the said boom foot rather than 2 coupling | bond part may be included.

  According to this configuration, the first main pipe and the second main pipe are connected to each other via the first diagonal member, the first coupling portion, and the second diagonal coupling member, and the second diagonal member, the first coupling portion, and The first main pipe and the second main pipe are separated from each other when a compressive load in the longitudinal direction is applied to the first main pipe and the second main pipe because the first main pipe and the second main pipe are connected to each other via the first oblique connection member. Can be prevented from being deformed. Further, in this configuration, the third main pipe and the fourth main pipe are connected to each other via the third diagonal member, the second connecting portion, and the fourth diagonal connecting member, and the fourth diagonal member, the second connecting portion, and The third main pipe and the fourth main pipe are separated from each other when a compressive load in the longitudinal direction is applied to the third main pipe and the fourth main pipe because the third main pipe and the fourth main pipe are connected to each other through the third oblique connection member. Can be prevented from being deformed. Therefore, in this configuration, it is possible to maintain the shape of the main pipe located on both lateral sides of the lower boom while reducing the lateral deflection that occurs in the lattice boom.

  In the configuration in which the first connecting member includes the first connecting portion and the second connecting member includes the second connecting portion, the first connecting portion is connected to the first main pipe and the second main pipe. The second coupling part is preferably connected to the third main pipe and the fourth main pipe.

  According to this configuration, since the first main pipe and the second main pipe can be connected by the first coupling portion, the shape stability of the first main pipe and the second main pipe can be improved. In addition, since the third main pipe and the fourth main pipe can be connected by the second coupling portion, the shape stability of the third main pipe and the fourth main pipe can be improved.

  As described above, according to the present invention, it is possible to reduce lateral deflection that occurs in the lattice boom during crane operation while avoiding a significant increase in the weight and lateral width of the lattice boom.

1 is a schematic side view of a crawler crane to which a lattice boom according to a first embodiment of the present invention is applied. It is the perspective view which showed typically the lower boom of the lattice boom by 1st Embodiment of this invention. It is the right view which showed typically the lower boom vicinity of the lattice boom by 1st Embodiment of this invention. It is a figure which shows partially the junction part vicinity of the front-end | tip part of a main pipe and the front-end | tip part of a diagonal material among the lower booms shown in FIG. It is a figure which shows partially the junction part vicinity of a diagonal material, a coupling | bond part, and a center connection material among the lower booms shown in FIG. It is the right view which showed typically the lower boom vicinity of the lattice boom by the 1st comparative example. It is the right view which showed typically the lower boom vicinity of the lattice boom by the 2nd comparative example. It is the right view which showed typically the lower boom vicinity of the lattice boom by 2nd Embodiment of this invention. It is the right view which showed typically the lower boom vicinity of the lattice boom by 3rd Embodiment of this invention. It is the right view which showed typically the lower boom vicinity of the lattice boom by the modification of 4th Embodiment of this invention. It is a figure which shows the simulation result of the lifting capability of the crane which provided the lattice boom of each embodiment. It is a figure which shows partially the range in which the right side reinforcement lattice member was provided among the right side surfaces of the lattice boom by the modification of 1st Embodiment of this invention. It is a figure which shows partially the junction part vicinity of the front-end | tip part of a main pipe and the front-end | tip part of a diagonal material by the modification of each embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, with reference to FIGS. 1-5, the structure of the lattice boom by 1st Embodiment of this invention is demonstrated.

  The lattice boom 1 according to the first embodiment is provided on, for example, a crawler crane as shown in FIG. This crane has a lower traveling body 102 and an upper revolving body 104 mounted on the lower traveling body 102 so as to be rotatable about a vertical axis. The lattice boom 1 is provided on the upper swing body 104 so as to be raised and lowered. A base end portion of the lattice boom 1 is attached to the upper swing body 104, and the lattice boom 1 is raised and lowered with the base end portion as a fulcrum. A hook 108 is lifted from the tip of the lattice boom 1 via a rope 106, and the suspended load is suspended from the tip of the lattice boom 1 by the hook 108. The lattice boom 1 has a lattice structure having four side surfaces. Specifically, the lattice boom 1 is attached to the upper swing body 104 as shown in FIG. 1 and stands upright, a right side surface facing the right side of the crane, a left side surface facing the left side of the crane, and a front side of the crane. A lattice structure having a front side face toward the rear and a rear side face toward the rear of the crane. The left and right side surfaces of the lattice boom 1 face the turning direction of the upper turning body 104.

  The lattice boom 1 includes a lower boom 2 attached to the upper swing body 104 and an upper boom 4 connected to the distal end side of the lower boom 2.

  As shown in FIG. 2, the lower boom 2 includes a lower boom body 16 having a boom foot 12 and four main pipes 14, and a plurality of auxiliary members 18. The right side surface of the lower boom 2 is included in the concept of the first side surface of the present invention, and the left side surface of the lower boom 2 is included in the concept of the second side surface of the present invention. In FIG. 2, in order to make each material easy to understand, the main pipe 14 is a thick solid line, and among the secondary materials 18, a right front diagonal material 32, a right rear diagonal material 34, a right connecting material 36, and a right main pipe, which will be described later. Front end side connecting member 37, right main pipe base end side connecting member 38, left front oblique member 42, left rear oblique member 44, left connecting member 46, left main pipe front end connecting member 47 and left main pipe base member The end side connecting material 48 is drawn with a solid line thinner than the main pipe 14, and the front side diagonal material 52 and the rear side diagonal material 54, which will be described later, of the auxiliary material 18 are drawn with broken lines.

  The boom foot 12 of the lower boom body 16 is a portion that is attached to the upper swing body 104, and is disposed at the most proximal end of the lower boom 2. The boom foot 12 includes a right foot portion 12 a located on the right side surface of the lower boom 2 and a left foot portion 12 b located on the left side surface of the lower boom 2. The right foot portion 12a is included in the concept of the first foot portion of the present invention, and the left foot portion 12b is included in the concept of the second foot portion of the present invention. Both the right foot portion 12a and the left foot portion 12b are plate bodies having a predetermined thickness. These two foot portions 12a and 12b are respectively provided with corresponding through holes in the thickness direction. Then, a foot pin (not shown) is inserted into a through hole in a mounting portion (not shown) of the upper swing body 104 arranged between the both foot portions 12a and 12b and a through hole in the both foot portions 12a and 12b. Both foot portions 12 a and 12 b are attached to the upper swing body 104.

  The four main pipes 14 extend from the boom foot 12 to the distal end side of the lower boom 2. These four main pipes 14 are respectively arranged at positions corresponding to the vertices of a quadrangle in a cross section perpendicular to the longitudinal direction of the lower boom 2 (the axial direction of the lattice boom 1). The four main pipes 14 include a right front main pipe 20a and a right rear main pipe 20b located on the right side of the lower boom 2, a left front main pipe 22a located on the left side of the lower boom 2, and It consists of the left rear main pipe 22b. The right front main pipe 20a is included in the concept of the first main pipe of the present invention, and the right rear main pipe 20b is included in the concept of the second main pipe of the present invention. The left front main pipe 22a is included in the concept of the third main pipe of the present invention, and the left rear main pipe 22b is included in the concept of the fourth main pipe of the present invention.

  As shown in FIG. 3, the right front main pipe 20 a and the right rear main pipe 20 b are arranged on the right side surface of the lower boom 2 so as to be separated from each other in the front-rear direction perpendicular to the axial direction of the lower boom 2. Further, the left front main pipe 22 a and the left rear main pipe 22 b are disposed on the left side surface of the lower boom 2 so as to be separated from each other in the front-rear direction perpendicular to the axial direction of the lower boom 2.

  In this specification, the terms “right side” and “right side” applied to the lattice boom 1 mean the right side and the right side of the crane when the lattice boom 1 is arranged at the front of the crane as shown in FIG. The terms “left side” and “left side” of the lattice boom 1 mean the left side and the left side of the crane in the same state. Further, the term “front side” applied to the lattice boom 1 means the front side of the lattice boom 1 that faces the front of the crane when the lattice boom 1 stands at the front of the crane as shown in FIG. The term “rear side” according to 1 means the rear side of the lattice boom 1 that faces the rear of the crane in the same state.

  Each of the sub-materials 18 is made of a round pipe having a smaller diameter than the main pipe 14, and a plurality of sub-materials 18 are arranged on the right side surface, the left side surface, the front side surface, and the rear side surface of the lower boom 2.

  The secondary member 18 disposed on the right side surface of the lower boom 2 includes a right front diagonal member 32, a right rear diagonal member 34, a right connecting member 36, a right main pipe tip side connecting member 37, and a right main member. An inter-pipe proximal end side connecting member 38 is included. The right front diagonal member 32 is included in the concept of the first diagonal member of the present invention, and the right rear diagonal member 34 is included in the concept of the second diagonal member of the present invention. The material 36 is included in the concept of the first connecting material of the present invention.

  The right front diagonal member 32 is connected to the front end of the right front main pipe 20a on the right side surface of the lower boom 2, and between the right front main pipe 20a and the right rear main pipe 20b as it goes to the right foot 12a side. It extends linearly so as to gradually approach the intermediate position.

  The right rear diagonal 34 is connected to the front end of the right rear main pipe 20b on the right side surface of the lower boom 2 and between the right front main pipe 20a and the right rear main pipe 20b as it goes to the right foot 12a side. It extends linearly so as to gradually approach the intermediate position. The right rear diagonal 34 is disposed symmetrically with the right front diagonal 32 with respect to the center in the width direction of the right side surface of the lower boom 2. The tip of the right rear diagonal 34 is joined to the tip of the right rear main pipe 20b as shown in FIG. Specifically, the joint surface of the front end portion of the right rear oblique member 34 is formed in a shape corresponding to the curved surface shape of the outer surface of the right rear main pipe 20b, and the joint surface of the front end portion is the outer surface of the right rear main pipe 20b. The outer edge of the front end portion of the right rear oblique member 34 is welded to the outer surface of the right rear main pipe 20b in a state where it is applied to the portion facing the inner side in the width direction of the right side surface of the lower boom 2. The tip of the right front diagonal member 32 is joined to the tip of the right front main pipe 20a in the same manner as the tip of the right rear diagonal 34 is joined to the tip of the right rear main pipe 20b. ing.

  The right connecting member 36 connects the base end portion of the right front diagonal member 32 and the base end portion of the right rear diagonal member 34 and the right foot portion 12 a on the right side surface of the lower boom 2. The right connecting member 36 includes a right connecting portion 36a and a right center connecting member 36b. The right coupling portion 36a is included in the concept of the first coupling portion of the present invention, and the right central coupling member 36b is included in the concept of the first central coupling material of the present invention.

  The right coupling portion 36 a is coupled to the base end portion of the right front diagonal member 32 and the base end portion of the right rear diagonal member 34. The right coupling portion 36 a is a round pipe that extends linearly in the width direction of the right side surface of the lower boom 2. The base end portion of the right front diagonal member 32 and the base end portion of the right rear diagonal member 34 are joined to the central portion in the longitudinal direction of the right coupling portion 36a. Specifically, the joint surface of the proximal end portion of the right front diagonal member 32 and the joint surface of the proximal end portion of the right rear oblique member 34 are both formed in a shape corresponding to the curved surface shape of the outer surface of the right coupling portion 36a. After being applied to a portion facing the distal end side of the lower boom 2 in the outer surface of the central portion in the longitudinal direction of the right coupling portion 36a, the outer edges of the base end portions of the two diagonal members 32, 34 are the right coupling portion 36a. It is welded to the outer surface (see FIG. 5).

  Further, the front end portion of the right coupling portion 36a is welded to a portion of the outer surface of the right front main pipe 20a facing the inner side in the width direction of the right side surface of the lower boom 2, and the rear end portion of the right coupling portion 36a. Is welded to a portion of the outer surface of the right rear main pipe 20b that faces the inner side in the width direction of the right side surface of the lower boom 2.

  The right center connecting member 36b is a round pipe extending along the center line between the right front main pipe 20a and the right rear main pipe 20b, and connects the right coupling portion 36a and the right foot portion 12a. Specifically, the distal end portion of the right center connecting member 36b is joined to the longitudinal center portion of the right connecting portion 36a, and the base end portion of the right center connecting member 36b is joined to the right foot portion 12a. . The joint surface at the tip of the right center connecting member 36b is formed in a shape corresponding to the curved surface shape of the outer surface of the right joint 36a, and the joint surface of the tip is the outer surface of the central portion in the longitudinal direction of the right joint 36a. The distal end of the right central connecting member 36b in a state where the proximal end portion of the right front oblique member 32 and the proximal end portion of the right rear oblique member 34 are applied to a portion located on the back side of the joined portion. The outer edge of the portion is welded to the outer surface of the right coupling portion 36a (see FIG. 5).

  The right side main pipe front end side connecting member 37 (see FIG. 3) connects the front end portion of the right front main pipe 20a and the front end portion of the right rear main pipe 20b to each other on the right side surface of the lower boom 2. ing. The right-side main pipe tip-end connecting member 37 is a round pipe that extends linearly in the width direction of the right side surface of the lower boom 2. The front end portion of the right main pipe front end side connecting member 37 is welded to a portion of the outer surface of the right front main pipe 20a facing the inner side in the width direction of the right side surface of the lower boom 2. A rear end portion of the connecting member 37 is welded to a portion of the outer surface of the right rear main pipe 20b facing the inner side in the width direction of the right side surface of the lower boom 2.

  The right main pipe base end side connecting member 38 (see FIG. 3) connects the right front main pipe 20a and the right rear main pipe 20b between them on the right side surface of the lower boom 2. Specifically, the right main pipe base end side connecting member 38 includes a right front main pipe connecting member 38a and a right rear main pipe connecting member 38b, and the right center connecting member 36b between the connecting members 38a and 38b. The right front main pipe 20a and the right rear main pipe 20b are connected to each other with the intervening. More specifically, the right front main pipe connection member 38a and the right rear main pipe connection member 38b are disposed at a position between the right coupling portion 36a and the right foot portion 12a in the longitudinal direction of the right side surface of the lower boom 2. It is arranged on a straight line extending in the width direction of the right side surface of the lower boom 2. The right front main pipe connecting member 38a connects the right front main pipe 20a and the right center connecting member 36b, and the right rear main pipe connecting member 38b connects the right rear main pipe 20b and the right center connecting member 36b. is doing.

  As shown in FIG. 2, the secondary material 18 disposed on the left side surface of the lower boom 2 includes a left front diagonal material 42, a left rear diagonal material 44, a left connecting material 46, and a front end side between the left main pipes. A connecting material 47 and a left-side main pipe proximal end side connecting material 48 are included. The left front oblique member 42, the left rear oblique member 44, the left connecting member 46, the left main pipe distal end connecting member 47 and the left main pipe proximal end connecting member 48 are composed of the right front oblique member 32 and the right rear oblique member. 34, the right side connecting member 36, the right main pipe distal end side connecting member 37, and the right main pipe proximal end side connecting member 38. The left front diagonal 42 is included in the concept of the third diagonal of the present invention, and the left rear diagonal 44 is included in the concept of the fourth diagonal of the present invention. The left connecting member 46 is included in the concept of the second connecting member of the present invention.

  The left connecting member 46 includes a left connecting part 46a and a left central connecting member 46b. The left connecting part 46a and the left central connecting member 46b are configured in the same manner as the right connecting part 36a and the right central connecting member 36b. Has been. The left joint 46a is included in the concept of the second joint of the present invention, and the left central connector 46b is included in the concept of the second central connector of the present invention.

  Further, the left main pipe base end side connection member 48 includes a left front main pipe connection member 48a and a left rear main pipe connection member 48b. The left front main pipe connection member 48a and the left rear main pipe connection member 48b are The right front main pipe connecting member 38a and the right rear main pipe connecting member 38b are configured in the same manner.

  The secondary member 18 disposed on the front side surface of the lower boom 2 includes a plurality of front diagonal members 52 disposed between the right front main pipe 20a and the left front main pipe 22a. These front diagonal members 52 connect the right front main pipe 20a and the left front main pipe 22a in a zigzag manner.

  The secondary member 18 disposed on the rear side surface of the lower boom 2 includes a plurality of rear diagonal members 54 disposed between the right rear main pipe 20b and the left rear main pipe 22b. These rear diagonal members 54 connect the right rear main pipe 20b and the left rear main pipe 22b in a zigzag manner.

  Similar to the four main pipes 14 of the lower boom 2, the upper boom 4 is disposed at a position corresponding to each vertex of a square in a cross section perpendicular to the longitudinal direction of the upper boom 4 (the axial direction of the lattice boom 1). Four upper main pipes 62 and a number of upper sub-materials 64 that connect adjacent upper main pipes 62 on the right side, left side, front side, and rear side of the upper boom 4. .

  The four main pipes 14 extend from the boom foot 12 to the distal end side of the lower boom 2. These four main pipes 14 are respectively arranged at positions corresponding to the vertices of a quadrangle in a cross section perpendicular to the longitudinal direction (axial direction) of the lower boom 2. The base end portion of each upper main pipe 62 is connected to the distal end portion of the corresponding main pipe 14 of the lower boom 2. As a result, when a lateral bending load is applied to the lattice boom 1, a compressive load or a tensile load is transmitted from the distal end side of the lattice boom 1 to the corresponding main pipe 14 of the lower boom 2 via the upper main pipe 62. The

  In the lattice boom 1 according to the first embodiment described above, when a lateral bending load is applied to the lattice boom 1, the compressive load generated on one of the left and right side surfaces is transferred to the upper revolving structure 104 having high rigidity. Since it is transmitted smoothly, the lateral deflection generated in the lattice boom 1 during crane operation is reduced.

  For example, a longitudinal compressive load acts on the right front main pipe 20a and right rear main pipe 20b of the lower boom 2 due to a lateral bending load applied to the lattice boom 1, and the left front main pipe 22a and left rear When a tensile load in the longitudinal direction acts on the main pipe 22b, the compressive load acting on the right front main pipe 20a and the right rear main pipe 20b is smoothly transmitted to the upper swing body 104. More specifically, when a lateral bending load is applied to the lattice boom 1, the compressive load acting on the right front main pipe 20a is applied to the right foot portion 12a via the right front diagonal member 32 and the right connecting member 36. The compressive load that is transmitted and acts on the right rear main pipe 20b is transmitted to the right foot portion 12a via the right rear diagonal member 34 and the right connecting member 36. That is, in the first embodiment, as in the first comparative example shown in FIG. 6, the main pipes 114a and 114b adjacent on the side surface of the lower boom 112 are connected in a zigzag manner with a plurality of diagonal members 116. In comparison, the compressive load acting on the two main pipes 20a and 20b can be directly transmitted to the right foot portion 12a via the diagonal members 32 and 34 and the right connecting member 36. The compressive load acting on both the main pipes 20a and 20b can be smoothly transmitted to the upper swing body 104 side. Similarly, a longitudinal compressive load acts on the left front main pipe 22a and the left rear main pipe 22b of the lower boom 2 due to a lateral bending load applied to the lattice boom 1, and the right front main pipe 20a and right side When a tensile load in the longitudinal direction is applied to the rear main pipe 20b, the left front diagonal member 42, the left rear diagonal member 44, and the left connecting member 46 are the right front diagonal member 32, the right rear diagonal member 34, and the right connecting member. The compression load acting on the left front main pipe 22a and the left rear main pipe 22b functions smoothly in the same manner as 36, and is smoothly transmitted to the upper swing body 104 side. From the above, in this first embodiment, when a lateral bending load is applied to the lattice boom 1, the compressive load acting on the main pipe 14 located on the right side surface or the left side surface of the lower boom 2 is the upper portion. Smooth transmission to the revolving structure 104 side suppresses bending deformation of the lower boom 2 in the lateral direction, and as a result, bending of the lattice boom 1 in the lateral direction that occurs during crane work is reduced.

  Further, since the bending of the lattice boom 1 in the lateral direction can be reduced by devising the arrangement of the auxiliary members 18 (the diagonal members 32, 34, 42, 44 and the connecting members 36, 46) in this way, the bending can be suppressed. Therefore, it is possible to eliminate the necessity of increasing the wall thickness and diameter of the main pipe 14 or to reduce the necessity. As a result, it is possible to suppress the lateral bending of the lattice boom 1 while avoiding a significant increase in the weight of the lattice boom 1.

  Further, for the same reason, the lateral deflection of the lattice boom 1 can be reduced without significantly increasing the lateral width of the lattice boom 1.

  By the way, as in the second comparative example shown in FIG. 7, in the structure in which the main pipes 114 a and 114 b adjacent on the left and right side surfaces of the conventional lower boom 112 are connected in a zigzag manner with a plurality of diagonal members 116. It is conceivable to suppress the lateral bending of the lower boom 112 by welding the reinforcing plates 118 to both side surfaces, and to reduce the lateral deflection of the lattice boom. The weight increases significantly. On the other hand, in the first embodiment, for the above reason, the lateral bending of the lattice boom 1 can be reduced without adding the reinforcing plate 118. As a result, the weight of the reinforcing plate 118 is significantly increased. While avoiding the increase, the lateral bending of the lattice boom 1 can be reduced.

  In the first embodiment, the right front main pipe 20a and the right rear main pipe 20b of the lower boom 2 are connected by the right coupling portion 36a, and the right main pipe proximal end side connecting member 38 and the right center are connected. Since the right front main pipe 20a and the right rear main pipe 20b are subjected to a compressive load in the longitudinal direction, the right front main pipe 20a and the right rear main pipe 20b are separated from each other because they are fastened by the connecting member 36b. Can be prevented from being deformed. Similarly, the left front main pipe 22a and the left rear main pipe 22b of the lower boom 2 are connected by the left connecting portion 46a and are connected by the left main pipe proximal end side connecting member 48 and the left center connecting member 46b. Therefore, when a compressive load in the longitudinal direction is applied to the left front main pipe 22a and the left rear main pipe 22b, the left front main pipe 22a and the left rear main pipe 22b are prevented from being deformed in a direction away from each other. be able to. From the above, the shape stability of each main pipe 20a, 20b, 22a, 22b can be improved.

(Second Embodiment)
Next, with reference to FIG. 8, the structure of the lattice boom 1 by 2nd Embodiment of this invention is demonstrated.

  Compared with the lattice boom 1 according to the first embodiment, the lattice boom 1 according to the second embodiment has a proximal end portion of the right front oblique member 32 and a proximal end portion of the right rear oblique member 34 positioned closer to the boom foot 12 on the right side. While being joined to the connecting member 36, the base end portion of the left front oblique member 42 and the base end portion of the left rear oblique member 44 are joined to the left connecting member 46 at a position closer to the boom foot 12.

  Specifically, the right front diagonal member 32 and the right rear diagonal member 34 extend to a position closer to the right foot portion 12a as compared to the case of the first embodiment, and the base ends of the two diagonal members 32, 34. It joins to the right side coupling | bond part 36a arrange | positioned in the position corresponding to a part. Although not shown in FIG. 8, the left front diagonal material 42 and the left rear diagonal material 44 are configured in the same manner as the right front diagonal material 32 and the right rear diagonal material 34, and in the case of the first embodiment. In comparison, it extends to a position closer to the left foot 12b side. And the base end part of the both diagonal materials 42 and 44 of the left side is joined to the left coupling | bond part 46a arrange | positioned in the position corresponding to those base end parts.

  Further, in the second embodiment, the lower boom 2 connects the right front diagonal member 32 and the right rear diagonal member 34 to the right front main pipe 20a and the right rear main pipe 20b and connects the two diagonal members 32, 34 to each other. The right diagonal member 72, the left front diagonal member 42 and the left rear diagonal member 44 are connected to the left front main pipe 22a and the left rear main pipe 22b, and the diagonal members 42 and 44 are connected to each other. And a material connecting material (not shown).

  Specifically, the right diagonal material connecting material 72 extends in the width direction on the right side surface of the lower boom 2 and is arranged in a straight line, and the right front diagonal material connecting material 72a, the right rear diagonal material connecting material 72b, and the right side. It has the diagonal material connection material 72c.

  The right front diagonal connecting material 72a connects the middle portion of the right front diagonal 32 and the right front main pipe 20a between the longitudinal middle portion of the right front diagonal 32 and the right front main pipe 20a. Yes. The right rear diagonal connecting material 72b connects the intermediate portion of the right rear diagonal 34 and the right rear main pipe 20b between the middle portion in the longitudinal direction of the right rear diagonal 34 and the right rear main pipe 20b. Yes. The right diagonal member 72c connects the diagonal members 32, 34 between the longitudinal intermediate portion of the right front diagonal member 32 and the longitudinal intermediate portion of the right rear diagonal member 34.

  The left diagonal connecting material is configured in the same manner as the right diagonal connecting material 72 on the left side surface of the lower boom 2, and the right front diagonal connecting material 72a, the right rear diagonal connecting material 72b, and the right diagonal material. It has a left front diagonal connecting material, a left rear diagonal connecting material, and a left diagonal connecting material (all not shown) corresponding to the intermediate connecting material 72c.

  The other structure of the lattice boom 1 according to the second embodiment is the same as that of the lattice boom 1 according to the first embodiment.

  Even with the lattice boom 1 according to the second embodiment, the same effect as the lattice boom 1 according to the first embodiment can be obtained.

(Third embodiment)
Next, with reference to FIG. 9, the structure of the lattice boom 1 by 3rd Embodiment of this invention is demonstrated.

  In the lattice boom 1 according to the third embodiment, the right connecting member 36 includes a right front oblique connecting member 76a and a right rear oblique connecting member 76b, and the right connecting portion 36a and the right front main member are provided by the right front oblique connecting member 76a. The pipe 20a is connected and the right connecting portion 36a and the right rear main pipe 20b are connected by the right rear oblique connecting member 76b. The right front diagonal connecting member 76a is included in the concept of the first diagonal connecting member of the present invention, and the right rear diagonal connecting member 76b is included in the concept of the second diagonal connecting member of the present invention. is there.

  The right front diagonal connecting member 76a is a round pipe that linearly extends so as to gradually approach the right front main pipe 20a from the central portion in the longitudinal direction of the right coupling portion 36a toward the right foot portion 12a. The front end portion of the right front diagonal connecting member 76a is joined to the longitudinal center portion of the right coupling portion 36a. The joint surface of the front end portion of the right front diagonal connecting member 76a is formed in a shape corresponding to the curved surface shape of the outer surface of the right joint portion 36a, and the joint surface of the tip portion is a central portion in the longitudinal direction of the right joint portion 36a. The outer edge of the right front diagonal connecting member 76a is attached to the portion located on the back side of the portion where the base end portion of the right front diagonal member 32 is joined on the outer surface of the right connecting portion 36a. It is welded to the outer surface. The base end portion of the right front diagonal connecting member 76a is a portion of the right front main pipe 20a that is located closer to the right foot portion 12a than the portion to which the right coupling portion 36a is joined, and is a base between the right main pipes. It joins with respect to the site | part of the vicinity of the site | part to which the end side connection material 38 is joined. The joint surface of the base end portion of the right front diagonal connecting member 76a is formed in a shape corresponding to the curved surface shape of the outer surface of the right front main pipe 20a, and the joint surface of the base end portion is the outer surface of the right front main pipe 20a. Of these, the outer edge of the base end portion of the right front diagonal connecting member 76a is welded to the outer surface of the right front main pipe 20a in a state of being applied to the position facing the inner side in the width direction of the right side surface of the lower boom 2.

  The right rear diagonal connecting member 76b is disposed symmetrically with the right front diagonal connecting member 76a with respect to the center in the width direction of the right side surface of the lower boom 2, and corresponds to the right front diagonal connecting member 76a. It has a structure.

  Although not shown in FIG. 9, in the third embodiment, the left connecting member 46 is the same as the right front oblique connecting member 76 a and the right rear oblique connecting member 76 b on the left side surface of the lower boom 2. The left front diagonal connecting material and the left rear diagonal connecting material are provided. The left connecting portion 46a and the left front main pipe 22a are connected by the left front diagonal connecting member, and the left connecting portion 46a and the left rear main pipe 22b are connected by the left rear oblique connecting member. The left front diagonal connecting material is included in the concept of the third diagonal connecting material of the present invention, and the left rear diagonal connecting material is included in the concept of the fourth diagonal connecting material of the present invention.

  Further, in the third embodiment, the right main pipe base end side connecting member 38 is composed of one round pipe extending in the width direction of the right side surface of the lower boom 2, and the right front main pipe 20 a and the right rear main pipe. 20b is directly connected. Similarly, the left main pipe base end side connecting member 48 is composed of one round pipe extending in the width direction of the left side surface of the lower boom 2 and directly connects the left front main pipe 22a and the left rear main pipe 22b. ing.

  The other configuration of the lattice boom 1 according to the third embodiment is the same as that of the lattice boom 1 according to the first embodiment.

  In the third embodiment, the right front main pipe 20a and the right rear main pipe 20b are connected to each other via the right front diagonal member 32, the right coupling portion 36a, and the right rear diagonal connection member 76b, and the right rear diagonal member 34. Since the right connecting portion 36a and the right front diagonal connecting member 76a are connected to each other, when a compressive load in the longitudinal direction acts on the right front main pipe 20a and the right rear main pipe 20b, both the main pipes 20a are connected. , 20b can be more effectively prevented from being deformed in directions away from each other. Similarly, the left front main pipe 22a and the left rear main pipe 22b are connected to each other via the left front diagonal member 42, the left connecting portion 46a and the left rear diagonal connecting member, and the left rear diagonal member 44 and the left connecting portion 46a. Since the left front main pipe 22a and the left rear main pipe 22b are subjected to a compressive load in the longitudinal direction, the main pipes 22a and 22b are separated from each other. It is possible to more effectively prevent deformation in the direction. Therefore, in the third embodiment, the shape of the main pipe 14 located on the left and right side surfaces of the lower boom 2 can be more effectively maintained while reducing the lateral deflection that occurs in the lattice boom 1.

  The other effects of the third embodiment are the same as the effects of the first embodiment.

(Fourth embodiment)
Next, with reference to FIG. 10, the structure of the lattice boom 1 by 4th Embodiment of this invention is demonstrated.

  In the lattice boom 1 according to the fourth embodiment, the secondary material 18 located on the right side surface of the lower boom 2 and the secondary material 18 located on the left side surface have the structure according to the first embodiment and the structure according to the third embodiment. It has a combined structure.

  Specifically, of the secondary members 18 located on the right side surface of the lower boom 2, the right connecting member 36 includes a right connecting portion 36 a, a right center connecting member 36 b, a right front oblique connecting member 76 a and a right rear oblique connecting member 76 b. Have In addition, the left connecting member 46 of the secondary members 18 located on the left side surface of the lower boom 2 includes a left connecting portion 46a, a left central connecting member 46b, a left front oblique connecting member, and a left rear oblique connecting member.

  Other configurations of the lattice boom 1 according to the fourth embodiment are the same as those of the lattice boom 1 according to the first embodiment.

  According to the fourth embodiment, it is possible to obtain the same effects as the effects of both the first embodiment and the third embodiment.

(Simulation of the hanging ability of the lattice boom according to the above embodiments)
Next, the result of the simulation which investigated the relationship between the structure of the lattice boom by each said embodiment and the reduction effect of the lateral deflection obtained by the structure is demonstrated. In this simulation, the effect of reducing lateral deflection was examined by examining the lifting ability of the lattice boom of each of the above embodiments. The result is shown in FIG. The lifting capacity in the simulation is expressed as a lifting load on the lattice boom. When a lateral load corresponding to 2% of the lifting load is applied to the tip of the lattice boom, the amount of lateral deflection of the lattice boom ( This corresponds to a suspension load such that the lateral displacement of the tip of the lattice boom is within 2% of the total length of the lattice boom. In addition, the vertical axis in FIG. 11 shows that the lifting capacity of a conventional lattice boom in which the main pipes adjacent to each other on both the left and right sides of the lower boom are connected in a zigzag manner with a plurality of diagonal members is defined as 100%. The ratio of the lifting ability of the lattice boom of the structure of each of the above embodiments to the ability is shown. In addition, as a comparative example of the above-described embodiment, a lattice boom (conventional example) having the above-described conventional structure and a lattice boom having the above-described conventional structure in which the thickness of the main pipe in the entire longitudinal direction is 1.6 times, FIG. 11 shows the lifting ability of a lattice boom having a lower boom of which a reinforcing plate is welded to both left and right side surfaces (second comparative example).

  From FIG. 11, the lattice booms of the first embodiment and the third embodiment have a lifting ability substantially equal to that of the lattice boom of the conventional structure in which the thickness of the main pipe in the longitudinal direction is 1.6 times larger. The lifting ability of the lattice boom of the second embodiment and the fourth embodiment is higher than that, and is equal to or higher than that in which the reinforcing plates are welded to the left and right side surfaces of the lower boom of the lattice boom of the conventional structure. It became clear that it became the lifting ability. That is, from this result, the lattice booms of the first embodiment and the third embodiment do not significantly increase the weight incurred when the thickness of the main pipe is increased 1.6 times in the conventional lattice boom. In the lattice booms of the second embodiment and the fourth embodiment, the reinforcing plates are provided on the left and right side surfaces of the lower boom in the conventional lattice boom. It has been found that the effect of reducing lateral deflection equal to or greater than the attachment of such a reinforcing plate can be obtained while avoiding a significant increase in weight incurred when attaching the reinforcing plate.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

  For example, as shown in FIG. 12, on the right side surface of the lower boom 2, the front end portion of the right front diagonal member 32 and the front end portion of the right rear diagonal member 34 are connected to the front end of the right front main pipe 20a via the right upper plate member 78. And the base end of the right center connecting member 36b through the right lower plate member 79, the right foot 12a, the right front main pipe 20a, and the right rear main pipe 20b. It may be connected to.

  In this case, the right upper plate member 78 is formed of a rectangular flat plate, and is fitted between the front end portion of the right front main pipe 20a and the front end portion of the right rear main pipe 20b. The edge corresponding to the location facing the width direction inner side of the right side surface of the lower boom 2 and the location facing the right foot portion 12a side of the outer surface of the right main pipe distal end side connecting member 37 among the outer surfaces of the distal end portion are welded. Is done. And the front-end | tip part of the right front diagonal material 32 and the front-end | tip part of the right rear diagonal material 34 are welded to the end surface by the side of the right foot part 12a among this right side upper board | plate material 78. FIG. The right lower plate member 79 is a flat plate, and is fitted between the base end portion of the right front main pipe 20a and the base end portion of the right rear main pipe 20b, and the base ends of both the main pipes 20a and 20b. Of the outer surface of the portion, the portion facing the inner side in the width direction of the right side surface of the lower boom 2 and the edge corresponding to the tip surface of the right foot portion 12a are welded. Then, the base end portion of the right center connecting member 36 b is welded to the distal end surface of the right lower plate member 79.

  Similarly, on the left side surface of the lower boom 2, the front end portion of the left front oblique member 42 and the front end portion of the left rear oblique member 44 are connected to the front end portion of the left front main pipe 22a and the left rear main portion via the left upper plate member. The base end portion of the left center connecting member 46b is connected to the left foot portion 12b, the left front main pipe 22a, and the left rear main pipe 22b via the left lower plate member while being connected to the tip end portion of the pipe 22b. Good.

  Moreover, as shown in FIG. 13, the front-end | tip part of the right back diagonal material 34 and the front-end | tip part of the right rear main pipe 20b may be connected via bracket 84a, 84b. Specifically, one bracket 84a is formed of a rectangular flat plate, and a portion facing the inner side in the width direction of the right side surface of the lower boom 2 out of the outer surface of the front end portion of the right rear main pipe 20b and the front end between the right main pipes. It welds to the corner part formed by the location which faces the right foot part 12a side among the outer surfaces of the rear-end part of the side connection material 37. As shown in FIG. The other bracket 84b is formed of a rectangular flat plate and is welded to the tip of the right rear oblique member 34. The one bracket 84a and the other bracket 84b are welded in a state where they are overlapped with each other.

  Similarly, the connection between the tip of the right front diagonal member 32 and the tip of the right front main pipe 20a, the connection between the tip of the left rear diagonal member 44 and the tip of the left rear main pipe 22b, and the left front diagonal. The connection between the tip of the material 42 and the tip of the left front main pipe 22a may be a connection via a bracket.

  The bracket attached to the tip of the main pipe and the bracket attached to the tip of the diagonal member may be fastened with bolts and nuts instead of being welded.

  Further, the right connecting member 36 has a base end portion of the right front oblique member 32 and a base end portion of the right rear oblique member 34 on the right side surface of the lower boom 2 at positions closer to the right foot portion 12a than these base end portions. It may be configured in any way as long as it is connected to any part of the lower boom body 16. Further, the left connecting member 46 has a base end portion of the left front oblique member 42 and a base end portion of the left rear oblique member 44 on the left side surface of the lower boom 2 at positions closer to the left foot portion 12b than the base end portions. It may be configured in any way as long as it is connected to any part of the lower boom body 16.

  Further, the present invention may be applied to a lattice boom provided in various cranes other than the crawler crane.

DESCRIPTION OF SYMBOLS 1 Lattice boom 2 Lower boom 4 Upper boom 12 Boom foot 12a Right foot part (1st foot part)
12b Left foot (second foot)
14 Main pipe 16 Lower boom body 18 Secondary material 20a Right front main pipe (first main pipe)
20b Right rear main pipe (second main pipe)
22a Left main pipe (third main pipe)
22b Left rear main pipe (4th main pipe)
32 Right front diagonal (first diagonal)
34 Right rear diagonal (second diagonal)
36 Right side connection material (first connection material)
36a Right side coupling part (first coupling part)
36b Right side center connecting material (first center connecting material)
42 Left front diagonal (third diagonal)
44 Left diagonal (fourth diagonal)
46 Left side connection material (second connection material)
46a Left side coupling part (second coupling part)
46b Left center connecting material (second center connecting material)
76a Right front diagonal connecting material (first diagonal connecting material)
76b Right rear diagonal connecting material (second diagonal connecting material)
104 Upper swing body

Claims (4)

It is a lattice boom that is attached to an upper swing body of a crane that is capable of swiveling so that it can be raised and lowered, and a suspended load is suspended from its tip,
A lower boom attached to the upper swing body, and an upper boom connected to a tip end side of the lower boom,
The lower boom is a boom foot attached to the upper swing body, and extends from the boom foot to the distal end side of the lower boom, at a position corresponding to each vertex of a quadrangle in a cross section perpendicular to the longitudinal direction of the lower boom. A lower boom body having a plurality of main pipes arranged and coupled to the boom foot, and a plurality of sub-materials arranged between adjacent main pipes of the main pipes,
The plurality of main pipes include a first main pipe and a second main pipe that are spaced apart from each other on a first side surface of the lower boom facing the turning direction of the upper swing body, and the lower boom. A third main pipe and a fourth main pipe that are spaced apart from each other on a second side that is the opposite side of the first side,
The plurality of sub-materials are connected to the tip end portion of the first main pipe on the first side surface, and intermediate between the first main pipe and the second main pipe toward the boom foot side. A first diagonal member extending so as to gradually approach the position, and on the first side surface, connected to the tip of the second main pipe, and toward the boom foot side, the first main pipe and the second main pipe. A second diagonal member extending so as to gradually approach an intermediate position between the pipe, and a base end portion of the first diagonal member and a base end portion of the second diagonal member and the lower portion on the first side surface; On the second side surface, a first connecting member that connects a base end portion of the first diagonal member and a portion located closer to the boom foot than the base end portion of the second diagonal member in the boom body, Connected to the tip of the third main pipe, the boom foot side A third diagonal member extending so as to gradually approach an intermediate position between the third main pipe and the fourth main pipe as it goes, and a tip of the fourth main pipe on the second side surface A fourth diagonal member extending so as to gradually approach an intermediate position between the third main pipe and the fourth main pipe toward the boom foot side, and the third diagonal member on the second side surface. Of the base end portion of the material and the base end portion of the fourth diagonal material and the lower boom body, the base end portion of the third diagonal material and the base end portion of the fourth diagonal material are located closer to the boom foot. A lattice boom including a second connecting member connecting the parts. The boom foot is located on the first side surface, and is located on the second side surface, a first foot portion coupled to a proximal end portion of the first main pipe and a proximal end portion of the second main pipe. And a second foot portion coupled to the base end portion of the third main pipe and the base end portion of the fourth main pipe,
The first connecting member includes a first coupling portion coupled to a proximal end portion of the first oblique member and a proximal end portion of the second oblique member, and between the first main pipe and the second main pipe. A first center connecting member extending along a center line and connecting the first coupling portion and the first foot portion;
The second connecting member includes a base end portion of the third diagonal member and a second joint portion connected to the base end portion of the fourth diagonal member, and between the third main pipe and the fourth main pipe. 2. The lattice boom according to claim 1, comprising a second center coupling member extending along a center line and coupling the second coupling portion and the second foot portion. The first coupling member includes a first coupling portion coupled to a proximal end portion of the first oblique member and a proximal end portion of the second oblique member, and the first coupling member toward the boom foot side from the first coupling portion. A first diagonal connecting member extending so as to gradually approach one main pipe and connecting the first connecting portion and a portion of the first main pipe located closer to the boom foot than the first connecting portion; The boom extends from the first coupling portion toward the boom foot side so as to gradually approach the second main pipe, and the boom is more than the first coupling portion of the first coupling portion and the second main pipe. Including a second diagonal connecting material that connects a portion located closer to the foot,
The second coupling member includes a second coupling portion coupled to a proximal end portion of the third diagonal member and a proximal end portion of the fourth diagonal member, and the second coupling member as the second footing portion is moved from the second coupling portion toward the boom foot side. A third diagonal connecting member extending so as to gradually approach the three main pipes and connecting the second connecting portion and a portion of the third main pipe located closer to the boom foot than the second connecting portion; The second coupling portion extends so as to gradually approach the fourth main pipe from the second coupling portion toward the boom foot side, and the boom is more than the second coupling portion of the second coupling portion and the fourth main pipe. The lattice boom according to claim 1, further comprising a fourth diagonal connecting member that connects a portion located closer to the foot.   The first coupling part is connected to the first main pipe and the second main pipe, and the second coupling part is connected to the third main pipe and the fourth main pipe. The lattice boom according to 2 or 3.

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