JP5364353B2 - Boom hoisting cylinder mounting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boom derricking cylinder installation structure capable of relieving the concentration of the stress produced in a boom. <P>SOLUTION: This boom derricking cylinder installation structure includes a plurality of plate members welded to the lower surface of the boom in a generally upright state. Each plate member includes a pair of vertical plates which extend in the longitudinal direction of the boom and are disposed on both left and right sides of the center axis of the boom, a rear plate to which the front end of the cylinder is connected, which extends in the lateral direction of the boom, and which is joined to the rear end of the vertical plate, and a cross plate which extends in the lateral direction of the boom and is disposed so as to cross the vertical plates. The vertical plate includes body parts extending parallel to each other and laterally enlarged parts which are integrated with the front ends of the body parts and which extend diagonally so that the distance therebetween is increased from the front ends of the body parts. The body part is divided into a front section and a rear section. The cross plate is provided so as to laterally extend through the gap between the front section and the rear section, and welded to the front section and the rear section. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a boom hoisting cylinder mounting structure for pivotally mounting a tip of a hydraulic cylinder for hoisting a crane boom.

Conventionally, a crane vehicle is known as a hoist for lifting and moving a heavy object. As shown in FIG. 7, the crane vehicle has a lower traveling body 6, an upper revolving body 5 provided on the upper portion of the lower traveling body 6 so as to be able to swivel around a vertical axis, and one end pivotally disposed on the upper revolving body 5. A boom 2 for hanging the hook 7 at the other end, a hydraulic cylinder (cylinder) 4 for raising and lowering the boom 2, and a bracket for attaching one end of the hydraulic cylinder 4 to the boom 2 so as to be rotatable (boom raising and lowering cylinder mounting structure) 3). The bracket 3 is fixed to the boom 2 by welding (see Patent Document 1).
JP 2001-151471 A

  However, in the technique of Patent Document 1, the bracket is joined to the boom only by a pair of plates (boom side cylinder pivot bracket 13) extending in the front-rear direction of the boom. There is a problem that stress is concentrated on the portion.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a boom hoisting cylinder mounting structure that can alleviate the concentration of stress generated in a boom.

  As means for solving the above-mentioned problems, the present inventors added a pair of plates extending in the width direction of the boom in addition to a pair of plates extending in the front-rear direction of the boom, and the boom and boom hoisting cylinder mounting structure. And a pair of plates extending in the front-back direction of the boom are extended so as to be bent away from each other toward the front of the boom, thereby reducing the uneven distribution of the joints. Furthermore, among the two plates extending in the width direction of the boom, the stress concentration is further alleviated by arranging the plate located on the front side of the boom closer to the direction of the plate located on the rear side of the boom. I found it. The present invention is a boom hoisting cylinder mounting structure that satisfies such conditions.

  The boom hoisting cylinder mounting structure of the present invention is a boom hoisting cylinder mounting structure that is provided on the lower surface of the boom of the crane and that is pivotably mounted at the tip of the cylinder for hoisting the boom. A plurality of plate members that are welded in an upright state, the plate members extending in the front-rear direction of the boom, and a pair of vertical plates disposed on both left and right sides of the center axis of the boom; A rear plate connected to a front end of the boom and connected to a rear end of the vertical plate; and a cross plate extending in the width direction of the boom and arranged to cross the vertical plate. The vertical plate includes a main body portion extending in parallel with each other, and a widening portion that is integrally connected to a front end of the main body portion and extends at an angle so as to increase a distance from the front end of the main body portion. The front side The crossing plate is provided so as to penetrate between the front part and the rear part in the width direction, and is welded to the front part and the rear part, respectively. It is characterized by being.

  According to the present invention, in addition to the pair of vertical plates, the rear plate and the cross plate are included, so that the joint area between the boom and the bracket can be increased, so that the stress generated in the boom can be dispersed. It is possible to alleviate the stress concentration generated in the substrate. Moreover, by providing the widening part which inclines and extends so that a mutual space | interval may spread from the front end of a main-body part, the uneven distribution of a junction part can be relieve | moderated and the stress concentration which arises in a boom can be relieve | moderated. . Further, the main body is divided into a front part and a rear part, and the crossing plate is provided so as to penetrate between the front part and the rear part in the width direction. That is, the vertical plate is composed of two plate members that are divided into two with the cross plate as a boundary. In other words, it is possible to position the cross board at a desired position in the front-rear direction of the boom simply by changing the dividing position of the vertical board. Therefore, it is possible to reduce the concentration of stress generated in the boom by bringing the intersecting plate closer to the rear plate.

  Moreover, it is preferable that the said wide part and the said front part consist of a single board | plate material, and the said wide part and the said front part are formed by the bending process of the said board | plate material.

  According to the present invention, the widened portion and the front portion of the main body are formed by bending the plate material. Therefore, the operation | work which joins a wide part and a main-body part is unnecessary, and it can avoid that intensity | strength falls in the boundary position of a wide part and a main-body part by joining.

  Moreover, it is preferable that the rear plate is provided with a cylinder pivoting portion for pivoting the end of the cylinder so as to protrude toward the rear side of the boom.

  According to this invention, the cylinder pivoting portion for pivoting the end of the cylinder is provided on the rear plate so as to protrude toward the rear side of the boom. It is connected to the rear of the mounting structure, and the load generated when the boom is raised and lowered can be efficiently transmitted to the boom on the front side of the boom raising and lowering cylinder mounting structure.

In addition, the crossing plate is inscribed in the pair of widened portions and outside the circle passing through the front ends of the pair of main body portions, and is installed on the rear side of the boom with respect to the front ends of the pair of main body portions. It is preferred that

  According to this invention, the cross plate is inscribed in the pair of widened portions and outside the circle passing through the front ends of the pair of main body portions, and is installed on the rear side of the boom, so that stress is concentrated. The part which arises can be avoided.

  Further, another boom hoisting cylinder mounting structure of the present invention is a boom hoisting cylinder mounting structure provided on the lower surface of a boom of a crane, wherein a tip of a cylinder for hoisting the boom is rotatably mounted. A pair of vertical plates that are welded in a state of being substantially upright on the peripheral surface of the boom, the plate members extending in the front-rear direction of the boom, and arranged on both the left and right sides of the central axis of the boom A front end portion of the cylinder is connected, extends in the width direction of the boom, is connected to a rear end of the vertical plate, and extends in the width direction of the boom, and is arranged so as to intersect the vertical plate. The vertical plate includes a main body portion extending in parallel with each other, and a widening portion that is integrally connected to the front end of the main body portion and that is inclined and extended from the front end of the main body portion so as to increase the distance between each other. Comprising said cross board The main body portion of the vertical plate is provided so as to penetrate between the intermediate portion and the left and right side portions in the front-rear direction of the boom, and the main body portion, The intermediate portion and the left and right side portions are welded to each other.

  According to the present invention, in addition to the pair of vertical plates, the rear plate and the cross plate are included, so that the joint area between the boom and the bracket can be increased, so that the stress generated in the boom can be dispersed. It is possible to alleviate the stress concentration generated in the substrate. Moreover, by providing the widening part which inclines and extends so that a mutual space | interval may spread from the front end of a main-body part, the uneven distribution of a junction part can be relieve | moderated and the stress concentration which arises in a boom can be relieve | moderated. . Further, the crossing plate is divided into an intermediate portion and left and right side portions, and the main body portion of the vertical plate is provided so as to penetrate between the intermediate portion and the left and right side portions in the front-rear direction of the boom. In other words, since the cross board is composed of three plate members that are divided into three with the two vertical boards as a boundary, the position of the cross board can be positioned at a desired position in the front-rear direction of the boom. become. Therefore, it is possible to reduce the concentration of stress generated in the boom by bringing the intersecting plate closer to the rear plate.

  Moreover, it is preferable that the said vertical board consists of a single board | plate material, and the said wide part and the said main-body part are formed by the bending process of the said board | plate material.

  According to this invention, a vertical board consists of a single board | plate material, and a wide part and a main-body part are formed by the bending process of a board | plate material. Therefore, the operation | work which joins a wide part and a main-body part is unnecessary, and it can avoid that intensity | strength falls in the boundary position of a wide part and a main-body part by joining.

  Moreover, it is preferable that the rear plate is provided with a cylinder pivoting portion for pivoting the end of the cylinder so as to protrude toward the rear side of the boom.

  According to this invention, the cylinder pivoting portion for pivoting the end of the cylinder is provided on the rear plate so as to protrude toward the rear side of the boom. It is connected to the rear of the mounting structure, and the load generated when the boom is raised and lowered can be efficiently transmitted to the boom on the front side of the boom raising and lowering cylinder mounting structure.

In addition, the crossing plate is inscribed in the pair of widened portions and outside the circle passing through the front ends of the pair of main body portions, and is installed on the rear side of the boom with respect to the front ends of the pair of main body portions. It is preferred that

  According to this invention, the cross plate is inscribed in the pair of widened portions and outside the circle passing through the front ends of the pair of main body portions, and is installed on the rear side of the boom, so that stress is concentrated. The part which arises can be avoided.

  According to the present invention, the concentration of stress generated in the boom can be reduced.

  Below, the boom hoisting cylinder mounting structure of this invention is demonstrated in detail using drawing.

(Embodiment 1)
The boom hoisting cylinder mounting structure is provided on the lower surface of the boom 21 of the crane. And the front-end | tip part of the hydraulic cylinder which raises / lowers the boom 21 is attached rotatably via this boom raising / lowering cylinder attachment structure. In the following, when referring to the front-rear direction of the boom, it means the longitudinal direction of the boom. Further, the front of the boom means the front end side of the boom, and the rear of the boom means the base end side of the boom. Further, the boom width direction means a direction substantially perpendicular to the boom axial direction.

  FIG. 1 is a perspective view showing a state in which the bracket (boom hoisting cylinder mounting structure) 3 according to the first embodiment is fixed to the lower surface of the boom 21. The bracket 3 according to the first embodiment has a plurality of plate members that are welded in a substantially upright state to the lower surface of the boom 21. As shown in FIG. 1, a vertical plate 34 for distributing the load in the front-rear direction of the boom 21, a rear plate 31 for distributing the load in the width direction of the boom 21, and the rear plate 31. A cross plate 32 that is disposed on the front side of the boom 21 and further disperses the load in the width direction of the boom 21 and a tip end portion of a hydraulic cylinder for raising and lowering the boom 21 are rotatable with respect to the boom 21. A hydraulic cylinder pivot portion 35 for mounting and a bottom plate 33 for ensuring the rigidity of the bracket 3 are provided.

  FIG. 2 is a plan view of the bracket 3 of the first embodiment. FIG. 3 is a front view of the bracket 3 of the first embodiment. FIG. 4 is a side view of the bracket 3 according to the first embodiment.

  The vertical plates 34 are a pair of members that extend in the front-rear direction of the boom 21 and are arranged on both the left and right sides of the central axis of the boom 21. The vertical plate 34 includes a main body 34 a provided in parallel to the central axis of the boom 21, and a widened portion 34 b provided at the front end of the main body 34 a and extending in a direction away from each other toward the front of the boom 21. Including. Hereinafter, the boundary position between the rear end of the widened portion 34b and the front end of the main body portion 34a is referred to as a bending point P1.

  The main body 34a is composed of a plate material divided into two. Specifically, the main body portion 34a includes a first main body portion (front side portion) 34a1 located on the front side of the boom 21 and a second main body portion (rear side) located on the rear side of the boom 21 with respect to the first main body portion 34a1. Part) 34a2. A crossing plate 32 is provided at a boundary portion between the first main body portion 34a1 and the second main body portion 34a2 so as to separate the first main body portion 34a1 and the second main body portion 34a2.

  As described above, the widened portion 34b is a portion extending in a direction away from the widened portion 34b of the other vertical plate 34 from the bending point P1 toward the front of the boom 21 (see FIG. 2). As described above, since the distance between the pair of widened portions 34 b is provided so as to expand toward the front of the boom 21, uneven distribution of the joint portion of the bracket 3 with respect to the boom 21 can be reduced.

  Further, the widened portion 34b and the first main body portion 34a1 are made of a single plate material. The widened portion 34b and the first main body 34a1 of the vertical plate 34 are formed by bending a plate material at the bending point P1 in FIGS. 2 and 3. Therefore, the operation | work which joins the wide part 34b and 1st main-body part 34a1 is unnecessary, and it can avoid that intensity | strength falls by the joining in the boundary position of the wide part 34b and 1st main-body part 34a1. .

  Therefore, the vertical plate 34 according to the present embodiment is configured by a pair of plate members including the widened portion 34b and the first main body portion 34a1 and a pair of second main body portions 34a2, that is, a total of four plate materials. The

  The rear plate 31 extends in the width direction of the boom 21 (a direction substantially perpendicular to the axial direction of the boom 21) and is connected to the rear end of the vertical plate 34. As shown in FIG. 4, the rear plate 31 has a shape in which the upper edge portion is along the peripheral surface of the boom 21. In the present embodiment, the upper edge portion of the rear plate 31 has a substantially U-shaped shape so as to be along the peripheral surface of the boom 21 having a substantially elliptical cross section. Further, the rear plate 31 protrudes outward from the vertical plate 34 and is welded to the circumferential surface of the boom 21. And the stress which generate | occur | produces in the boom 21 can be disperse | distributed, so that the part which protrudes outward from this vertical board 34 and is welded to the surrounding surface of the boom 21 is long. The rear plate 31 and the vertical plate 34 are joined by welding at a portion where they intersect each other.

  The cross board 32 extends in the width direction of the boom 21 and is arranged so as to cross the vertical board 34. The cross plate 32 is provided substantially parallel to the rear plate 31. Similarly to the rear plate 31, the cross plate 32 also protrudes outward from the vertical plate 34 and is welded to the peripheral surface of the boom 21. And the stress which generate | occur | produces in the boom 21 can be disperse | distributed, so that the part which protrudes outward from this vertical board 34 and is welded to the surrounding surface of the boom 21 is long. The intersecting plate 32 and the longitudinal plate 34 are fixed to each other at a portion where they intersect each other by welding.

Moreover, the cross board 32 is arrange | positioned between the 1st main-body part 34a1 of the above-mentioned vertical board 34, and the 2nd main-body part 34a2. Accordingly, the arrangement position of the cross plate 32 in the front-rear direction of the boom 21 (longitudinal direction of the boom 21) is determined by the balance between the length of the first main body 34a1 and the length of the second main body 34a2. In the present embodiment, the cross plate 32 is inscribed in the pair of widened portions 34b, and the front ends of the pair of main body portions 34a (that is, the front ends of the pair of first main body portions 34a1 and the rear ends of the widened portions 34b). And on the rear side of the boom 21 with respect to the front ends of the pair of main body portions 34a . Thereby, the cross board 32 can be arrange | positioned avoiding from the part which the stress in the boom 21 produces especially concentrated.

  Two sets of hydraulic cylinder pivoting portions 35 are attached to the rear surface of the rear plate 31 so as to protrude rearward of the boom 21. Each hydraulic cylinder pivot portion 35 is a rear surface of the rear plate 31, and is a pair of first pivot plates 35 a provided on an extension line of the vertical plate 34, and a pair of first pivot plates 35 a. A pair of second pivot plates 35b provided at a predetermined distance from the first pivot plate 35a, and a reinforcing plate 35c provided on an extension line of the second pivot plate 35b via the rear plate 31. including. The first pivot plate 35a is formed with a circular mounting hole 35a1, and the second pivot plate 35b is similarly formed with a circular mounting hole 35b1. The mounting holes 35a1 and the mounting holes 35b1 are positioned so as to face each other. A pivot that rotatably holds the tip of the hydraulic cylinder is inserted into the mounting hole 35a1 and the mounting hole 35b1. The reinforcing plate 35c is provided for the purpose of preventing the rear plate 31 from being deformed by receiving the force transmitted by the second pivot plate 35b. The reinforcing plate 35c is provided substantially parallel to the second main body portion 34a2 of the vertical plate 34 with one end thereof joined to the rear plate 31 and the other end joined to the cross plate 32.

  One end of each hydraulic cylinder is attached to one set of hydraulic cylinder pivots. That is, since two sets of hydraulic cylinder pivot portions 35 are provided in the bracket 3 of the present embodiment, two hydraulic cylinders are attached. When the tip of the hydraulic cylinder is interposed between the first pivot plate 35a and the second pivot plate 35b of each hydraulic cylinder pivot portion 35, the pivot (not shown) becomes the first pivot portion. A mounting hole 35a1 formed in 35a, an insertion hole formed in the tip of the hydraulic cylinder, a mounting hole 35b1 formed in the second pivot 35b, a mounting hole 35b1 formed in the second pivot 35b, and a hydraulic pressure It fixes in the state which penetrated in order of the insertion hole formed in the front-end | tip part of a cylinder, and the mounting hole 35a1 formed in the 1st pivot part 35a. In this way, the tip of each hydraulic cylinder is attached to the bracket 3 so as to be rotatable around the pivot axis.

  As described above, the hydraulic cylinder pivoting portion 35 for pivoting the end of the hydraulic cylinder is provided on the rear plate 31 so as to protrude toward the rear side of the boom 21, thereby The part is connected to the rear of the bracket 3, and the load generated when the boom 21 is raised and lowered can be efficiently transmitted to the boom 21 on the front side of the bracket 3.

  The bottom plate 33 is fixed to the lower end of the vertical plate 34, the rear plate 31, the cross plate 32, and the hydraulic cylinder pivot portion 35, and is provided so as to partially cover the lower side of the bracket 3. Openings 33 a and 33 b are formed in the bottom plate 33. By forming such openings 33a and 33b, the weight of the bracket 3 can be reduced while securing the rigidity of the bracket 3 with the bottom plate 33.

  FIG. 5 is a view for explaining weld lines L <b> 1 to L <b> 4 when the bracket 3 of the present embodiment is welded to the boom 21. As shown in FIG. 5, when the bracket 3 is fixed to the boom 21 by welding, the pair of vertical plates 34 are fixed to the lower surface of the boom 21 by welding along the welding line L1 or L2, respectively. The rear plate 31 is welded and fixed to the lower surface of the boom 21 along the weld line L3, and the cross plate 32 is fixed to the lower surface of the boom 21 along the weld line L4. In this manner, the bracket 3 is attached to the boom 21 by the upper edge portion of each plate member constituting the bracket 3 being directly welded to the lower surface of the boom 21.

  Here, the relationship between the welding position of the cross plate 32 and the maximum stress generated in the boom 21 will be described. It is known that an extremely high stress is generated in the boom 21 from the vicinity of the bending point P1 to the front of the bending point P1. When the cross plate 32 is disposed at such a location where stress is concentrated, the maximum stress increases more and more, and the strength of the material decreases due to deformation of the boom 21 or repeated stress acting on the material. So-called fatigue is likely to occur. Therefore, in the present embodiment, the cross plate 32 of the bracket 3 is arranged along the weld line L4 as shown in FIG. 5 by arranging the cross plate 32 on the rear side of the boom 21 from the bending point P1. Is bonded to the boom 21 to avoid the local concentration of stress.

  According to the first embodiment, the main body portion 34a is divided into a first main body portion 34a1 and a second main body portion 34a2, and the crossing plate 32 has a width between the first main body portion 34a1 and the second main body portion 34a2. It is provided so as to penetrate in the direction. That is, the vertical plate 34 is configured by two plate members that are divided into two with the cross plate 32 as a boundary. In other words, it is possible to position the cross plate 32 at a desired position in the front-rear direction of the boom 21 only by changing the division position of the vertical plate 34. Therefore, it is possible to reduce the concentration of stress generated in the boom 21 by bringing the cross plate 32 closer to the rear plate 31 side.

(Embodiment 2)
FIG. 6 is a plan view of the bracket 3 of the second embodiment. In the bracket 3 of the first embodiment, the main body portion 34a of the vertical plate 34 is divided into a first main body portion 34a1 and a second main body portion 34a2, whereas the bracket 3 of the second embodiment is shown in FIG. As shown, the crossing plate 32 is divided into a pair of left and right side portions 32a and an intermediate portion 32b, and the main body portion 34a of the vertical plate 34 is not divided. That is, each vertical board 34 of Embodiment 2 is comprised with the single board | plate material, respectively.

  Specifically, the pair of left and right side portions 32a are fixed to the outer surface of the main body portion 34a of the vertical plate 34 by welding, and are provided so as to protrude outward from the outer surface of the main body portion 34a. The left and right side portions 32 a have a shape that extends from the lower surface side of the bracket 3 toward the upper surface side along the peripheral surface of the bracket 3, and the upper edge portion is fixed to the peripheral surface of the bracket 3 by welding. Is done.

  Moreover, the intermediate part 32b is provided through the main-body part 34a of the vertical board 34 on the extension line of the right-and-left both-sides part 32a. Therefore, both ends of the intermediate portion 32 b are fixed to the inner side surfaces of the pair of main body portions 34 a by welding, and the upper edge portion is fixed to the lower surface of the bracket 3 by welding.

  According to the second embodiment, the intersecting plate 32 is divided into the intermediate portion 32b and the left and right side portions 32a, and the main body portion 34a of the vertical plate 34 has a boom between the intermediate portion 32b and the left and right side portions 32a. 21 is provided so as to penetrate in the front-rear direction. That is, since the cross board 32 is composed of three plate members that are divided into three parts with the two vertical boards 34 as a boundary, the position of the cross board 32 is positioned at a desired position in the front-rear direction of the boom 21. It becomes possible to make it. Therefore, it is possible to reduce the concentration of stress generated in the boom 21 by bringing the cross plate 32 closer to the rear plate 31 side.

  In the above embodiment, the vertical plate 34 has been bent to form the main body 34a and the widened portion 34b. However, the present invention is not limited to this. The form which comprises the vertical board 34 using the main-body part 34a and the wide part 34b which each consist of a separate board | plate material may be sufficient. In this case, the front end of the main body 34a and the rear end of the widened portion 34b are joined by welding.

  A telescopic two-stage boom 21 (hereinafter, the boom at the rear end side is referred to as a basic boom 21a, and the boom extending toward the front end side is referred to as a telescopic boom 21b) is limited under the restraint conditions and load conditions as shown in FIG. The stress which arises in the basic boom 21a was calculated | required using the element method.

  Here, the constraint condition will be described in detail. The rear end of the basic boom 21a is attached to be rotatable only around the horizontal axis. Similarly, the base end portion of the hydraulic cylinder 4 is attached so as to be rotatable only around a horizontal axis parallel to the horizontal axis that is the center of rotation of the rear end of the basic boom 21a.

  Regarding the load condition, the reaction force generated by the weight of the boom 21 and the suspension load was input to the distal end side of the telescopic boom 21b.

  As for the structure of the bracket 3, as in the first embodiment, the main body 34 a of the vertical plate 34 is divided into two parts, a first main body 34 a 1 and a second main body 34 a 2, and the first main body 34 a 1 and the second main body 34 a 2 are separated. A configuration in which the cross plate 32 is provided so as to penetrate the boom 21 in the width direction between the main body portion 34a2 (see FIG. 2). Then, as shown in FIG. 9, the analysis was performed by changing the position of the cross board 32 (distance L from the bending point P1).

  The analysis results are shown in Table 1.

  As shown in Table 1, it can be seen that the maximum stress generated in the boom 21 along the cross plate 32 decreases as the distance L from the bending point P1 to the cross plate 32 increases.

It is a perspective view which shows the state by which the bracket of Embodiment 1 was fixed to the lower surface of the boom. FIG. 3 is a plan view of the bracket according to the first embodiment. FIG. 3 is a front view of the bracket according to the first embodiment. 3 is a side view of the bracket according to Embodiment 1. FIG. It is a figure for demonstrating the weld line at the time of welding the bracket of Embodiment 1 to a boom. 6 is a plan view of a bracket according to Embodiment 2. FIG. It is a figure for demonstrating a crane vehicle. It is a figure for demonstrating the analysis conditions of the analysis by a finite element method in an Example. It is the schematic of the plane of the bracket for demonstrating the installation position of a cross board in an Example.

Explanation of symbols

3 Bracket (Boom hoisting cylinder mounting structure)
31 Rear plate 32 Crossing plate 32a Left and right side portions 32b Intermediate portion 34 Vertical plate 34a Main body portion 34a1 First main body portion (front side portion)
34a2 Second body part (rear part)
34b Widening part 35 Hydraulic cylinder pivot part (cylinder pivot part)
4 Hydraulic cylinder (cylinder)

Claims (8)

A boom hoisting cylinder mounting structure provided on the lower surface of the boom of the crane, wherein a tip of a cylinder for hoisting the boom is rotatably mounted,
A plurality of plates that are welded in a substantially upright state on the lower surface of the boom;
The plate material is
A pair of vertical plates that extend in the front-rear direction of the boom and are arranged on both left and right sides of the central axis of the boom;
A front plate connected to the front end of the cylinder, extending in the width direction of the boom, and connected to the rear end of the vertical plate;
An intersecting plate that extends in the width direction of the boom and is arranged to intersect with the longitudinal plate,
The vertical plate includes a main body portion extending in parallel with each other, and a widening portion that is integrally connected to the front end of the main body portion, and that is inclined and extended from the front end of the main body portion so as to increase the distance between each other.
The main body is divided into a front part and a rear part,
The boom hoisting cylinder is characterized in that the crossing plate is provided so as to penetrate between the front side portion and the rear side portion in the width direction, and is welded to each of the front side portion and the rear side portion. Mounting structure.   The boom hoisting cylinder mounting structure according to claim 1, wherein the widened portion and the front portion are formed of a single plate material, and the widened portion and the front portion are formed by bending the plate material.   The boom hoisting cylinder mounting structure according to claim 1 or 2, wherein a cylinder pivoting portion for pivoting an end portion of the cylinder is provided on the rear plate so as to protrude rearward of the boom. The cross plate is inscribed in the pair of widened portions and outside the circle passing through the front ends of the pair of main body portions, and is installed on the rear side of the boom with respect to the front ends of the pair of main body portions. The boom hoisting cylinder mounting structure according to any one of claims 1 to 3. A boom hoisting cylinder mounting structure provided on the lower surface of the boom of the crane, wherein a tip of a cylinder for hoisting the boom is rotatably mounted,
A plurality of plate members welded in a substantially upright state on the peripheral surface of the boom;
The plate material is
A pair of vertical plates that extend in the front-rear direction of the boom and are arranged on both left and right sides of the central axis of the boom;
A front plate connected to the front end of the cylinder, extending in the width direction of the boom, and connected to the rear end of the vertical plate;
An intersecting plate that extends in the width direction of the boom and is arranged to intersect with the longitudinal plate,
The vertical plate includes a main body portion extending in parallel with each other, and a widening portion that is integrally connected to the front end of the main body portion, and that is inclined and extended from the front end of the main body portion so as to increase the distance between each other.
The cross plate is divided into an intermediate portion and left and right side portions,
The main body portion of the vertical plate is provided so as to penetrate between the intermediate portion and the left and right side portions in the front-rear direction of the boom, and the main body portion, the intermediate portion, and the left and right side portions are welded to each other. Boom hoisting cylinder mounting structure characterized by being made.   The boom hoisting cylinder mounting structure according to claim 5, wherein the vertical plate is made of a single plate material, and the widened portion and the main body portion are formed by bending the plate material. The boom hoisting cylinder mounting structure according to claim 5 or 6, wherein a cylinder pivoting portion for pivoting an end portion of the cylinder is provided on the rear plate so as to protrude rearward of the boom. The cross plate is inscribed in the pair of widened portions and outside the circle passing through the front ends of the pair of main body portions, and is installed on the rear side of the boom with respect to the front ends of the pair of main body portions. The boom hoisting cylinder mounting structure according to any one of claims 5 to 7.

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