JP5752573B2 - Telescopic boom and manufacturing method of telescopic boom - Google Patents

Description

  The present invention relates to a telescopic boom and a method for manufacturing the telescopic boom.

  2. Description of the Related Art Conventionally, there has been known a telescopic boom that is provided on a crane so that it can be raised and lowered, and Patent Document 1 shown below shows an example of such a telescopic boom.

  The telescopic boom shown in Patent Document 1 includes a plurality of cylindrical boom members having different diameters, and a small-diameter inner boom member is inserted inside a large-diameter outer boom member. The inner boom member can move relative to the outer boom member in the axial direction, and the telescopic boom can be expanded and contracted by the relative movement of the inner boom member. The inner boom member has a cylindrical main body and an end member attached to a base end portion (rear end portion) of the main body (see, for example, FIG. 6 of Patent Document 1). The end member holds an upper sliding pad that slides with respect to the inner surface of the upper portion of the outer boom member when the inner boom member moves relative to the outer boom member in the axial direction. The end member holds the upper sliding pad so that the upper sliding pad protrudes from the upper end of the base end portion of the inner boom member and can come into contact with the upper inner surface of the outer boom member.

  Further, the inner boom member is loaded on the distal end side of the inner boom member by the load of the suspended load suspended from the distal end portion of the telescopic boom, and as a result, the proximal end portion of the inner boom member is , Receive upward force. At this time, the upper sliding pad supports the proximal end portion of the inner boom member with respect to the inner surface of the upper portion of the outer boom member. In this state, the base end portion of the inner boom member receives a force that crushes the base end portion in the vertical direction. The end member also functions as a stiffening member for increasing the rigidity of the base end portion of the main body of the inner boom member with respect to this force. The end member is disposed so as to be orthogonal to the axial direction of the inner boom member, and the two plates disposed at a distance from each other in the axial direction are connected to each other. And a connecting portion connected between the two. One of the two plates is disposed so as to face the end surface of the base end of the main body. The base end portion of the main body is welded to the one plate body.

  Further, a lower sliding pad is provided on the inner surface of the lower portion of the front end portion (front end portion) of the outer boom member. The lower sliding pad is slidably in contact with the outer surface of the lower portion of the inner boom member that moves in the axial direction, and supports the inner boom member from below. Further, a member such as a pad stopper for fixing the lower sliding pad is provided on the inner surface of the lower portion of the tip portion of the outer boom member.

JP-T 9-501384

  However, in the telescopic boom as described above, the base end portion of the inner boom member main body is welded to the one plate body of the end member disposed so as to face the end surface of the base end portion. This causes a problem that the assemblability of the telescopic boom is deteriorated. The reason is as follows.

  When the base end portion of the main body of the inner boom member is welded to the one plate body of the end member facing the end surface, fillet welding is performed along the outer periphery of the base end portion of the main body. . In this case, in order to secure a welding margin, the one plate body must be formed to be larger than a cross section orthogonal to the axial direction of the base end portion of the main body, and as a result, the base end of the main body In a state where the portion is welded to the end member, the one plate body protrudes outside the outer surface of the base end portion of the main body. Then, when the base end portion of the inner boom member formed in this way is inserted into the outer boom member when the telescopic boom is assembled, it protrudes outward from the outer surface of the base end portion of the main body of the one plate body. The portion may interfere with a member such as a pad stopper provided on the inner surface of the lower portion of the tip portion of the outer boom member. For this reason, it becomes difficult to insert the base end part of an inner boom member in an outer boom member, and the assembly property of an expansion-contraction boom worsens.

  Further, the telescopic boom as described above has a problem that it is difficult to achieve both the weight reduction of the end member of the inner boom member and the securing of the rigidity of the base end portion of the inner boom member.

  Specifically, since the end member used for the boom member inside the telescopic boom is heavy, in order to improve workability when attaching the end member to the body of the inner boom member. It is desired to reduce the weight of the end member. However, since the end member is a member for increasing the rigidity of the base end portion of the inner boom member, if the weight of the end member is reduced by omitting unnecessary components, the base end of the inner boom member is reduced. It becomes difficult to ensure the rigidity of the part.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to improve the assemblability of the telescopic boom and to connect the upper sliding pad at the base end portion of the inner boom to the upper portion of the outer boom. It is intended to reduce the weight of the end member of the inner boom and to secure the rigidity of the base end portion of the inner boom while holding it at a suitable position where it can slide on the inner surface.

  In order to achieve the above object, an extendable boom according to the present invention is an extendable boom that is provided in a crane so as to be able to be raised and lowered, and is configured to be extendable and retractable. An inner boom that is inserted and is movable relative to the outer boom in the axial direction; and a proximal end portion of the inner boom that is inserted into the outer boom, the inner boom being disposed relative to the outer boom. An upper sliding pad that slides with respect to the inner surface of the upper part of the outer boom when relatively moving, and the inner boom includes an inner boom body formed in a cylindrical shape, and a proximal end portion of the inner boom body And an end member that increases the rigidity of the base end portion of the inner boom body, and the inner boom body forms an upper portion in a cross section orthogonal to the axial direction of the inner boom body. An upper piece, and a lower piece that is formed so as to exhibit a curved shape with an open top in the cross section, and is joined to the lower end of the upper piece at the upper left and right sides forming the upper opening. The base end portion of the piece is formed with a fitting portion that protrudes further toward the base end side of the telescopic boom than the base end portion of the upper piece, and the end member is fitted into the end boom. A first vertical plate portion disposed so as to be orthogonal to the axial direction of the main body and facing the base end portion of the upper piece, and welded to the base end portion of the upper piece; It was fitted in the fitting part in a state of being arranged in parallel with the first vertical plate part with a gap on the base end side of the telescopic boom with respect to the vertical plate part, and welded to the inner surface of the fitting part. Second vertical plate portion, first vertical plate portion and second vertical plate portion Between the portions located on the upper side of the fitting portion of the first vertical plate portion and the second vertical plate portion, and the upper sliding pad. And a pad storage section for storing.

  In this telescopic boom, the fitting portion of the lower piece of the inner boom body projects to the proximal end side of the telescopic boom from the proximal end portion of the upper piece, and the second end member fitted into the fitting portion. Since the vertical plate portion is welded to the inner surface of the fitting portion, the outer edge portion of the end member can be prevented from protruding outside the outer surface of the base end portion of the lower piece. As a result, when the base end portion of the inner boom is inserted into the outer boom when the telescopic boom is assembled, the constituent member such as the pad stopper provided on the inner surface of the lower portion of the outer boom distal end portion. Can be prevented, and the assembly of the telescopic boom can be improved. Further, in this telescopic boom, the end member is fitted and welded into the fitting portion of the lower piece of the inner boom main body, so that the rigidity of the proximal end portion of the inner boom is integrated with this fitting portion and the end member. Can be used to increase That is, in this configuration, the fitting portion can be used as a part of a stiffening member for increasing the rigidity of the proximal end portion of the inner boom. Like a conventional end member, it is arranged so as to oppose the end face of the base end portion of the inner boom body, and the two plates arranged at intervals in the axial direction of the inner boom are connected by a connecting portion. In this structure, one of the two plates facing the end surface of the base end portion of the inner boom body has a portion welded to the lower portion of the base end portion of the inner boom body and the connecting portion. However, in this configuration, it is possible to secure the rigidity of the base end portion of the inner boom by substituting these portions with fitting portions. Therefore, the weight of the end member can be reduced by omitting those portions. Therefore, in this configuration, it is possible to ensure the rigidity of the proximal end portion of the inner boom while reducing the weight of the end member. Furthermore, in this structure, the fitting part protrudes to the base end side of the telescopic boom from the base end part of the upper piece, and is located above the fitting part among the first vertical plate part and the second vertical plate part. Since the pad storage portion for storing the upper sliding pad is provided between the portions, the upper sliding pad is placed on the outer boom at the base end portion of the inner boom even if the end member is fitted in the fitting portion. It is possible to hold it at a suitable position where it can be slidably contacted with the inner surface of the upper part of the plate.

  In the telescopic boom, it is preferable that the first vertical plate portion has a portion fitted into the fitting portion and welded to the inner surface of the fitting portion.

  In this configuration, the joint strength between the end member and the fitting portion can be increased by welding the first vertical plate portion and the inner surface of the fitting portion, and the proximal end of the inner boom composed of the end member and the fitting portion. The rigidity of the part can be further increased.

  In the telescopic boom, the fitting portion has upper left and right upper edge portions that form an opening at the upper portion of the fitting portion, and the upper and lower edge portions on both the left and right sides extend along the axial direction of the inner boom body. And the end member is connected to the first vertical plate portion and the second vertical plate portion, and is placed on the left upper edge portion and welded to the upper edge portion. It is preferable that the first vertical plate portion and the second vertical plate portion are coupled to each other and have a right side placement portion that is placed on the upper edge portion of the right side and welded to the upper edge portion.

  In this configuration, end welding is performed by welding the left mounting portion of the end member and the upper left edge of the fitting portion, and by welding the right mounting portion of the end member and the upper right edge of the fitting portion. The joint strength between the part member and the fitting part can be further increased, and the rigidity of the base end part of the inner boom composed of the end part member and the fitting part can be further increased.

  In the configuration in which the first vertical plate portion is fitted into the fitting portion and welded to the inner surface of the fitting portion, the first vertical plate portion is in a cross section orthogonal to the axial direction of the inner boom body. It consists of a left first vertical plate portion and a right first vertical plate portion spaced apart from each other on the left and right with respect to the center in the left-right direction, and the second vertical plate portion is It consists of a left second vertical plate portion and a right second vertical plate portion that are spaced apart from each other on the left and right, and the axial connection portion includes the left first vertical plate portion and the left second vertical plate portion. A left axial connecting portion that connects the right first vertical plate portion and the right second vertical plate portion to each other, and the left axial connecting portion. And the right axial direction connecting portion is arranged to be spaced from each other to the left and right with respect to the center in the left-right direction. Rukoto is preferable.

  According to this configuration, it is possible to easily perform the welding operation on the inner surface of the fitting portion of the portion fitted in the fitting portion among the left first vertical plate portion and the right first vertical plate portion constituting the first vertical plate portion. Can do. Specifically, if the first vertical plate portion and the second vertical plate portion are each composed of a single plate that is not divided into left and right, the portion of the first vertical plate portion that is fitted into the fitting portion is The inner boom is hidden behind the second vertical plate portion when viewed from the proximal end side toward the distal end side, and approaches the welded portion between the inner surface of the fitting portion and the first vertical plate portion from the proximal end side of the inner boom. There is no route for. For this reason, it becomes difficult to weld the inner surface of the fitting portion and the first vertical plate portion. On the other hand, in this configuration, the first vertical plate portion is divided into a left first vertical plate portion and a right first vertical plate portion that are spaced apart from each other on the left and right sides, and the second vertical plate portion is It is divided into a left second vertical plate portion and a right second vertical plate portion that are spaced apart from each other on the left and right, and a connecting portion is further divided into a left connecting portion and a right connecting portion that are spaced apart from each other on the left and right. Therefore, it is possible to approach the welded portion between the inner surface of the fitting portion and the first vertical plate portion through the space between the left and right members from the proximal end side of the inner boom. For this reason, the welding operation | work with respect to the fitting part inner surface of the part inserted in the fitting part among the 1st vertical board parts can be performed easily.

  In this case, it is preferable that the said end part member has the connection part between right and left which connects those connection parts between the said left side axial direction connection part and the said right side axial direction connection part.

  According to this configuration, even if the first vertical plate portion, the second vertical plate portion, and the connecting portion of the end member are divided into left and right members as described above, the left and right members are connected via the left and right connecting portions. It can connect, and the rigidity of an end member can be secured.

  A telescopic boom manufacturing method according to the present invention is a method for manufacturing the telescopic boom described above, wherein an outer boom forming step for forming the outer boom, an inner boom forming step for forming the inner boom, and the outer boom forming. A telescopic boom assembling step for assembling the telescopic boom by inserting the inner boom formed in the inner boom forming step from the proximal end portion into the outer boom formed in the process from the distal end side to the proximal end side of the outer boom. The inner boom forming step includes welding the lower end of the upper piece and the upper end of the lower piece to form the inner boom main body, and the inner surface of the fitting portion of the lower piece. A fitting step of fitting the second vertical plate portion into the fitting portion so that an outer edge portion of the second vertical plate portion of the end member is in contact with, and fitting into the fitting portion The second vertical plate portion welding step of welding the outer edge portion of the second vertical plate portion to the inner surface of the fitting portion, and the first vertical plate portion of the end member being welded to the base end portion of the upper piece. Including a first vertical plate portion welding step.

  In this telescopic boom manufacturing method, since the second vertical plate portion of the end member is fitted into the fitting portion and welded to the inner surface of the fitting portion, the outer edge portion of the end member is the base end portion of the lower piece. Protruding outside the outer surface can be prevented. For this reason, when the base end portion of the inner boom is inserted into the outer boom, the base end portion of the inner boom interferes with constituent members such as a pad stopper provided on the inner surface of the lower portion of the front end portion of the outer boom. It can prevent, and the assembly property of a telescopic boom can be improved. Further, in this telescopic boom manufacturing method, the second vertical plate portion of the end member is welded to the inner surface of the fitting portion while the second vertical plate portion is fitted into the fitting portion of the lower piece of the inner boom body. Therefore, the work burden related to the welding work can be reduced. Specifically, the base end portion of the main body of the inner boom is opposed to the end surface of the end member while the opposite surface of the end member is abutted against the end surface of the base end portion of the main body of the cylindrical inner boom as in the prior art. When the welding is performed, it is difficult to maintain the positioned state while lifting the end member and accurately positioning the end member with respect to the base end portion of the inner boom body, and the work load increases. On the other hand, in the manufacturing method, the second vertical plate portion is fitted into the fitting portion so that the outer edge portion of the second vertical plate portion of the end member contacts the inner surface of the fitting portion of the inner boom body. Therefore, the end member can be temporarily fixed to the fitting portion, so that the state in which the end member is accurately positioned with respect to the fitting portion of the inner boom body can be easily maintained. Thus, the second vertical plate portion of the end member can be welded to the inner surface of the fitting portion. For this reason, the work burden concerning welding work can be reduced. Further, in this telescopic boom manufacturing method, there is a slight difference between the horizontal dimension of the portion of the second vertical plate portion of the end member fitted into the fitting portion and the horizontal dimension of the fitting portion. Even if there is, the left and right side parts of the fitting part are displaced in the left and right direction so that the inner dimension in the left and right direction of the fitting part becomes the right and left dimension of the portion of the second vertical plate part that fits in the fitting part. Can be adjusted to fit.

  In the telescopic boom manufacturing method, the fitting step and the second vertical plate portion welding step are performed prior to the inner boom body forming step, and the lower piece that is not welded to the upper piece in the fitting step. The second vertical plate portion of the end member is fitted into the fitting portion, and in the second vertical plate portion welding step, the second piece is fitted into the fitting portion of the lower piece that is not welded to the upper piece. You may weld the outer edge part of a said 2nd vertical board part to the inner surface of the fitting part.

  According to this structure, before the lower piece is welded to the upper piece, the second vertical plate portion of the end member is fitted into the fitting portion of the lower piece and welded. Is slightly different from the inner dimension in the left-right direction of the fitting part, the inner dimension in the left-right direction of the fitting part can be easily adjusted according to the dimension in the left-right direction of the second vertical plate part. Specifically, if the lower piece is welded to the upper piece and then welded by fitting the second vertical plate portion of the end member into the fitting portion of the lower piece, the second vertical to the fitting portion is assumed. Even when trying to adjust the inner dimension in the left-right direction of the fitting part to match the dimension in the left-right direction of the second vertical plate part when welding the plate part, the upper ends of the left and right sides of the lower piece are constrained by the upper piece, It is difficult to deform the fitting portion in the left-right direction, and it is difficult to adjust the inner dimension of the fitting portion in the left-right direction. On the other hand, in this configuration, when the second vertical plate portion of the end member is fitted into the fitting portion and welded, the lower piece is not yet welded to the upper piece, so the left and right side portions of the lower piece Is not restrained, and the left and right side portions of the fitting portion are easily displaced in the left-right direction, and the inner dimension of the fitting portion in the left-right direction is inserted into the fitting portion of the second vertical plate portion. It can be easily adjusted to fit the horizontal dimension.

  As described above, according to the present invention, the assembly of the telescopic boom can be improved, and the upper sliding pad can be slidably contacted with the inner surface of the upper part of the outer boom at the base end part of the inner boom. Further, the end member of the inner boom can be reduced in weight, and the rigidity of the proximal end portion of the inner boom can be ensured.

1 is a schematic side view of a crane to which a telescopic boom according to an embodiment of the present invention is applied. It is a partial longitudinal cross-sectional view along the axial direction of the outer side boom and inner side boom of the telescopic boom by one Embodiment of this invention. It is a perspective view of the base end part vicinity of the inner boom which comprises the telescopic boom by one Embodiment of this invention. It is a disassembled perspective view of the base end part of the inner side boom shown in FIG. It is sectional drawing of the direction orthogonal to the axial direction of an inner boom in the position between the 1st vertical board part and the 2nd vertical board part of the base end part of the inner boom by one Embodiment of this invention. It is sectional drawing of the state which mounted | wore the upper side sliding pad with the base end part of the inner side boom shown in FIG.

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

  First, with reference to FIGS. 1-6, the structure of the telescopic boom by one Embodiment of this invention is demonstrated.

  The telescopic boom 2 according to the present embodiment is provided on an upper swing body 102 of a crane as shown in FIG. A suspended load is suspended from the distal end of the telescopic boom 2 via a wire rope (not shown).

  The telescopic boom 2 of the present embodiment includes a plurality of boom members 3, a plurality of lower sliding pads 6 (see FIG. 2), and a plurality of upper sliding pads 8 (see FIGS. 2 and 6). I have.

  Each boom material 3 is formed in a cylindrical shape having different diameters, and the boom material 3 is combined by inserting the small-diameter boom material 3 inside the large-diameter boom material 3. Among the plurality of boom members 3, a boom member 3 having a large diameter and receiving a small-diameter boom member 3 is an outer boom 12, and the boom member 3 inserted into the outer boom 12 is an inner boom. 14. Accordingly, the boom material 3 positioned closest to the proximal end of the telescopic boom 2 is the outer boom 12, and the boom material 3 positioned closest to the distal end of the telescopic boom 2 is the inner boom 14. The material 3 is not only the outer boom 12 but also the inner boom 14. In the following description, “base end side” means the base end side of the telescopic boom 2, and “base end portion” means an end portion located on the base end side of the telescopic boom 2. Means. Further, the “tip side” means the tip side of the telescopic boom 2, and the “tip part” means an end portion located on the tip side of the telescopic boom 2.

  The outer boom 12 includes a cylindrical outer boom body 16. The outer boom body 16 basically has a common structure with an inner boom body 22 described later. The outer boom body 16 has an upper piece 17 and a lower piece 18 (see FIG. 2). The upper piece 17 and the lower piece 18 are each formed by bending a metal plate.

  The upper piece 17 is formed with rounded corners on the left and right sides of the top plate portion that linearly extends in the left-right direction in a cross section orthogonal to the axial direction, and left and right sides that extend linearly downward from both corner portions. It has a shape in which a side plate portion is formed. The upper piece 17 has a shape in which a lower portion is opened in a cross section orthogonal to the axial direction.

  The lower piece 18 is formed to have a left-right symmetrical curved shape with an upper portion opened in a cross section orthogonal to the axial direction. Specifically, the lower piece 18 has a curved portion that has an upwardly concave curved shape in a cross section perpendicular to the axial direction, and left and right side plate portions that linearly extend upward from the left and right ends of the curved portion. . The lower piece 18 is welded to the lower ends of the left and right side plate portions of the upper piece 17 at the upper ends of the left and right side plate portions that form the upper opening thereof, thereby forming a cylindrical outer boom body 16. ing.

  The lower sliding pad 6 is in sliding contact with the outer surface of the lower portion of the inner boom 14 that moves relative to the outer boom 12 in the axial direction and supports the inner boom 14 from below. The lower sliding pad 6 is provided on the inner surface of the lower portion of the distal end portion of the outer boom 12, specifically, the inner surface of the distal end portion of the curved portion of the lower piece 18 of the outer boom body 16. A plurality of lower sliding pads 6 are provided so as to line up along the curved shape of the inner surface of the curved portion of the lower piece 18. And the pad stopper 9 for fixing the lower side sliding pad 6 is each provided in the base end side (rear side) of each lower side sliding pad 6 among the inner surfaces of the front-end | tip part of the lower piece 18. Yes.

  The inner boom 14 can move in the axial direction relative to the outer boom 12, and the telescopic boom 2 can be expanded and contracted by the relative movement of the inner boom 14. The inner boom 14 has an inner boom body 22 and an end member 24.

  The inner boom body 22 is formed in a cylindrical shape, and is formed so that a cross section orthogonal to the axial direction thereof is similar to a cross section orthogonal to the axial direction of the outer boom main body 16. The inner boom body 22 includes an upper piece 26 and a lower piece 28.

  The upper piece 26 constitutes an upper portion in a cross section orthogonal to the axial direction of the inner boom body 22. The upper piece 26 is formed by bending a metal plate, and is formed so as to exhibit the same cross-sectional shape as the upper piece 17 of the outer boom body 16 described above in a cross section orthogonal to the axial direction. .

  The lower piece 28 constitutes a lower portion in a cross section orthogonal to the axial direction of the inner boom body 22. The lower piece 28 is formed by bending a metal plate, and is formed so as to exhibit the same cross-sectional shape as the lower piece 18 of the outer boom body 16 described above in a cross section orthogonal to the axial direction. . That is, the lower piece 28 is formed so as to exhibit a left-right symmetrical curved shape with an upper portion opened in a cross section orthogonal to the axial direction. Specifically, the lower piece 28 exhibits a curved shape that is concave upward in a cross section orthogonal to the axial direction, and is a straight line upward from the left and right ends of the curved portion that forms the bottom of the lower piece 28. Left and right side plate portions that extend in the direction. The lower piece 28 is welded to the lower ends of the left and right side plate portions of the upper piece 26 at the upper ends of the left and right side plate portions that form the upper opening thereof, thereby forming the cylindrical inner boom body 22. . In addition, a fitting portion 28e that protrudes to the proximal end side of the telescopic boom 2 from the proximal end portion of the upper piece 26 is formed at the proximal end portion (the end portion positioned on the proximal end side of the telescopic boom 2) of the lower piece 28. It is formed (see FIGS. 3 and 4).

  The fitting part 28e is a part into which the end member 24 is fitted. The fitting portion 28e is a part of the lower piece 28, and the cross-sectional shape in the direction orthogonal to the axial direction is the same as the cross-sectional shape of the lower piece 28 described above. That is, the fitting portion 28e includes a curved portion 28f having the same cross-sectional shape as the curved portion of the lower piece 28, a left side plate portion 28g having the same cross-sectional shape as the left side plate portion of the lower piece 28, and the lower piece. 28 and a right side plate portion 28h having the same cross-sectional shape (see FIG. 5). The fitting portion 28e has a left upper edge 28i that extends so as to be continuous with the left upper end of the lower piece 28, and a right upper edge 28j that extends so as to be continuous with the right upper end of the lower piece 28. The left upper edge portion 28i corresponds to the upper end of the left plate portion 28g, and the right upper edge portion 28j corresponds to the upper end of the right plate portion 28h. The left upper edge portion 28i and the right upper edge portion 28j form an opening in the upper portion of the fitting portion 28e, and extend along the axial direction of the inner boom body 22.

  The end member 24 is a member for increasing the rigidity of the proximal end portion of the inner boom body 22 and is a member that holds the upper sliding pad 8. The end member 24 includes a first vertical plate portion 31, a second vertical plate portion 32, an axial connection portion 33, a left placement portion 34a, a right placement portion 34b, and a left pad support portion 35a. The right side pad support portion 35b, the left end plate portion 36a, the right end plate portion 36b, and the left-right connecting portion 37 are provided. Each of these parts 31, 32, 33, 34a, 34b, 35a, 35b, 36a, 36b, and 37 is made of a metal plate.

  The first vertical plate portion 31 is disposed so as to be orthogonal to the axial direction of the inner boom body 22 and is disposed so as to face the base end portion of the upper piece 26 and to be in contact with the base end portion. And is welded to the base end portion of the upper piece 26. Moreover, the 1st vertical board part 31 is engage | inserted in the fitting part 28e, and has the part welded to the inner surface of the fitting part 28e.

  Specifically, the first vertical plate portion 31 includes a left first vertical plate portion 31a that is spaced apart from each other with respect to the center in the left-right direction in the cross section orthogonal to the axial direction of the inner boom body 22. It consists of a right first vertical plate portion 31b. The left first vertical plate portion 31a and the right first vertical plate portion 31b are arranged at equal distances on the left and right with respect to the center in the left-right direction and are formed in a shape that is symmetrical with respect to the center. ing. The left first vertical plate portion 31 a and the right first vertical plate portion 31 b are both formed in a flat plate shape orthogonal to the axial direction of the inner boom body 22.

  The left first vertical plate portion 31a protrudes from the left first vertical plate lower side portion 31c fitted into the fitting portion 28e and the upper opening of the fitting portion 28e, and from the left upper edge portion 28i of the fitting portion 28e. And the left first vertical plate upper portion 31d disposed on the upper side.

  The left first vertical plate lower portion 31c has an outer edge portion 31e shaped along the left inner surface of the fitting portion 28e. The left first vertical plate lower side portion 31c is fitted into the fitting portion 28e with its outer edge portion 31e in contact with the left inner surface of the fitting portion 28e. And the outer edge part 31e is welded to the inner surface of the fitting part 28e along the outer edge.

  The left first vertical plate upper portion 31 d is disposed so as to face the end surface of the left portion of the base end portion of the upper piece 26. The left first vertical plate upper portion 31 d is formed such that a portion from the left end portion to the upper end portion slightly protrudes outside the outer surface of the upper piece 26. The base end portion of the upper piece 26 is welded along the outer edge of the left first vertical plate upper portion 31d to the surface facing the base end portion of the upper piece 26. Further, the right end of the left first vertical plate upper portion 31d and the left first vertical plate lower portion 31c, that is, the right end of the left first vertical plate portion 31a, linearly extends vertically.

  The right first vertical plate portion 31b is arranged so as to be symmetrical with the left first vertical plate portion 31a with respect to the center in the left-right direction of the inner boom body 22, and the left first vertical plate portion 31a and the left and right It is formed in a symmetrical shape. That is, the right first vertical plate portion 31b includes a right first vertical plate lower portion 31h formed and arranged so as to be symmetrical with the left first vertical plate lower portion 31c, and the left first vertical plate. It has a right first vertical plate upper portion 31i formed and arranged so as to be symmetrical with the upper portion 31d. The right first vertical plate lower side portion 31h has an outer edge portion 31e that is symmetrical to the outer edge portion 31e of the left first vertical plate lower side portion 31c. The outer edge portion 31j is welded to the right inner surface of the fitting portion 28e in the same manner as the outer edge portion 31e. The right first vertical plate upper portion 31i is welded to the base end portion of the upper piece 26 in the same manner as the left first vertical plate upper portion 31d.

  The second vertical plate portion 32 (see FIG. 3 and FIG. 4) is disposed in parallel to the first vertical plate portion 31 with a space on the proximal end side of the telescopic boom 2 with respect to the first vertical plate portion 31. In this state, it is fitted into the fitting portion 28e and welded to the inner surface of the fitting portion 28e.

  Specifically, the second vertical plate portion 32 includes a left second vertical plate portion 32a that is spaced apart from each other with respect to the center in the left-right direction in the cross section orthogonal to the axial direction of the inner boom body 22. It consists of a right second vertical plate part 32b. The left second vertical plate portion 32a and the right second vertical plate portion 32b are arranged at equal distances on the left and right with respect to the center in the left-right direction and are formed in a shape that is symmetrical with respect to the center. ing. The left second vertical plate portion 32 a and the right second vertical plate portion 32 b are both formed in a flat plate shape orthogonal to the axial direction of the inner boom body 22. The left second vertical plate portion 32a and the right second vertical plate portion 32b are disposed at positions slightly closer to the distal end from the base end of the fitting portion 28e.

  The left second vertical plate portion 32a is formed in the same shape as the left first vertical plate portion 31a. That is, the left second vertical plate portion 32a is configured in the same manner as the left second vertical plate lower portion 32c and the left first vertical plate upper portion 31d configured in the same manner as the left first vertical plate lower portion 31c. Left upper second vertical plate upper portion 32d. Like the left first vertical plate lower side portion 31c, the left second vertical plate lower side portion 32c is fitted into the fitting portion 28e, and the outer edge portion 32e is welded to the left inner surface of the fitting portion 28e. .

  The right second vertical plate portion 32b is formed in the same shape as the right first vertical plate portion 31b. That is, the right second vertical plate portion 32b is configured in the same manner as the right second vertical plate lower portion 32h and the right first vertical plate upper portion 31i configured in the same manner as the right first vertical plate lower portion 31h. And a right second vertical plate upper portion 32i. Like the right first vertical plate lower side portion 31h, the right second vertical plate lower side portion 32h is fitted into the fitting portion 28e, and its outer edge portion 32j is welded to the right inner surface of the fitting portion 28e. .

  The axial connection part 33 connects the 1st vertical board part 31 and the 2nd vertical board part 32 between them. The axial connection portion 33 includes a left axial connection portion 33a that connects the left first vertical plate portion 31a and the left second vertical plate portion 32a therebetween, a right first vertical plate portion 31b, and a right second vertical plate. It consists of the right side axial direction connection part 33b which connects the part 32b between them. The left axial connecting portion 33a and the right axial connecting portion 33b are arranged at a distance from each other with respect to the center in the left / right direction of the inner boom body 22. Specifically, the left axial connection portion 33a and the right axial connection portion 33b are arranged at equal distances on the left and right with respect to the center in the left-right direction and are symmetrical with respect to the center in the left-right direction. It is formed in the shape to become.

  The left axial direction connecting portion 33a connects the right ends of the left first vertical plate portion 31a and the left second vertical plate portion 32a. The left axial connection portion 33a has a vertical dimension equal to the vertical dimension of the right end of the left first vertical plate portion 31a and the left second vertical plate portion 32a, and is disposed along the right ends of the vertical plate portions 31a and 32a. It consists of a rectangular flat plate. The left axial connecting portion 33a is disposed perpendicular to the left first vertical plate portion 31a and the left second vertical plate portion 32a. The front end side (front side) edge of the left axial connection portion 33a and the right end edge of the left first vertical plate portion 31a are welded to each other along the extending direction of the both end edges, and the left axial connection portion 33a. The base end side (rear side) end edge and the right end edge of the left second vertical plate portion 32a are welded to each other along the extending direction of the both end edges. Moreover, the lower end of the left side axial direction connection part 33a is welded to the inner surface of the bottom part of the fitting part 28e.

  The right axial connecting portion 33b connects the left ends of the right first vertical plate portion 31b and the right second vertical plate portion 32b. The right axial connecting portion 33b has a joint structure similar to that of the left axial connecting portion 33a, the left first vertical plate portion 31a, and the left second vertical plate portion 32a. It is welded to the second vertical plate portion 32b. Further, the lower end of the right axial connecting portion 33b is welded to the inner surface of the bottom portion of the fitting portion 28e, similarly to the lower end of the left axial connecting portion 33a.

  The left mounting portion 34a is coupled to the left first vertical plate portion 31a, the left second vertical plate portion 32a, and the left axial connection portion 33a, and is mounted on the left upper edge portion 28i of the fitting portion 28e. The left upper edge portion 28i is welded. Specifically, the left mounting portion 34a is formed of a flat plate arranged perpendicular to the left first vertical plate portion 31a, the left second vertical plate portion 31b, and the left axial connection portion 33a. The left mounting portion 34a is configured such that the outer edge portion 31e of the left first vertical plate lower side portion 31c and the outer edge portion 32e of the left second vertical plate lower side portion 32c are in contact with the curved inner surface on the left side of the fitting portion 28e. In a state in which the lower vertical portions 31c and 32c of both the vertical plates are fitted in the fitting portion 28e, the lower surface of the left mounting portion 34a is disposed so as to contact the left upper edge portion 28i of the fitting portion 28e. . The left mounting portion 34a includes a portion disposed in a space surrounded by the left first vertical plate portion 31a, the left second vertical plate portion 32a, and the left axial connection portion 33a, and slightly extends from the portion to the left side. And a protruding portion. The right end edge of the left mounting portion 34a is welded to the left side surface of the left axial connecting portion 33a, and the left first vertical plate portion 31a, the left second vertical plate portion 32a, and the left shaft of the left mounting portion 34a. The edge on the distal end side of the portion disposed in the space surrounded by the direction connecting portion 33a is welded to the proximal side surface of the left first vertical plate portion 31a, and the proximal end edge of the portion is The left second vertical plate portion 32a is welded to the front end surface. Further, the left mounting portion 34a has a portion that enters the lower side of the left end portion that protrudes to the left side of the left end of the left first vertical plate lower portion 31c in the left first vertical plate upper portion 31d. The lower end of the protruding left end portion of the left first vertical plate upper side portion 31d is welded to the upper surface. The left mounting portion 34a has a portion that enters the lower side of the left second vertical plate upper side portion 32d that protrudes to the left side of the left end of the left second vertical plate lower side portion 32c. The lower end of the protruding left end portion of the left second vertical plate upper portion 32d is welded to the upper surface of the upper left side. The left mounting portion 34a is disposed such that the lower surface thereof is in contact with the left upper edge portion 28i of the fitting portion 28e, and the left upper edge portion 28i extends on the lower surface in a direction in which the left upper edge portion 28i extends. Is welded along.

  The right mounting portion 34b is coupled to the right first vertical plate portion 31b, the right second vertical plate portion 32b, and the right axial connection portion 33b, and is placed on the right upper edge portion 28j of the fitting portion 28e. The right upper edge portion 28j is welded. The right placement portion 34b is formed in a symmetrical shape with the left placement portion 34a, and is disposed in a symmetrical manner with the left placement portion 34a. And the right mounting part 34b is the right first vertical plate part in the same manner as the welding of the left mounting part 34a to the left first vertical plate part 31a, the left second vertical plate part 32a and the left axial connection part 33a. It is welded to 31b, the right 2nd vertical board part 32b, and the right side axial direction connection part 33b. The right placement portion 34b is welded to the right upper edge portion 28j of the fitting portion 28e in the same manner as the welding of the left placement portion 34a to the left upper edge portion 28i of the fitting portion 28e.

  The left pad support portion 35a is a portion that supports a left upper sliding pad 8a described later from below. The left pad support portion 35a is a rectangular flat plate, and is disposed on the upper side from the left placement portion 34a. The left pad support portion 35a is disposed perpendicular to the left first vertical plate upper portion 31d, the left second vertical plate upper portion 32d, and the left axial connection portion 33a, and is surrounded by these portions 31d, 32d, and 33a. Are arranged in a designated space. The right end edge of the left pad support portion 35a is welded to the left side surface of the left axial connection portion 33a, and the end edge of the left pad support portion 35a is the base end side of the left first vertical plate upper portion 31d. The edge on the base end side of the left pad support portion 35a is welded to the surface on the tip end side of the left second vertical plate upper portion 32d. Of the left pad support portion 35a and the left first vertical plate upper portion 31d, the left second vertical plate upper portion 32d, and the left axial support portion 33a, the portion located above the left pad support portion 35a. A left pad storage portion 24a for storing the upper left sliding pad 8a is configured.

  The right pad support portion 35b (see FIGS. 5 and 6) is a portion that supports an upper right slide pad 8b described later from below. The right pad support portion 35b is formed in a symmetrical shape with the left pad support portion 35a, and is disposed in a symmetrical manner with the left pad support portion 35a. Further, the right side pad support portion 35b is formed in the same manner as in the welding of the left side pad support portion 35a to the left side first vertical plate upper portion 31d, the left side second vertical plate upper portion 32d, and the left side axial direction connecting portion 33a. It welds with respect to the board upper part 31i, the right side 2nd vertical board upper part 32i, and the right side axial direction connection part 33b. Of the right pad support portion 35b and the right first vertical plate upper portion 31i, the right second vertical plate upper portion 32i, and the portion located on the upper side of the right pad support portion 35b of the right axial connection portion 33b, A right pad storage portion 24b for storing the upper right sliding pad 8b is configured.

  The left end plate portion 36a is a rectangular flat plate arranged perpendicularly to the left mounting portion 34a, the left pad support portion 35a, the left first vertical plate upper portion 31d and the left second vertical plate upper portion 32d, It fits in the space enclosed by these each part 34a, 35a, 31d, 32d. The left end plate portion 36a is arranged in the vicinity of the left end of the left pad support portion 35a, the left first vertical plate upper portion 31d, and the left second vertical plate upper portion 32d. The upper end edge of the left end plate portion 36a is welded to the lower surface of the left pad support portion 35a, and the lower end edge of the left end plate portion 36a is welded to the upper surface of the left placement portion 34a. Further, the end edge on the distal end side of the left end plate portion 36a is welded to the base end side surface of the left first vertical plate upper portion 31d, and the base end side edge of the left end plate portion 36a is the left second vertical plate. It is welded to the tip side surface of the upper part 32d.

  The right end plate part 36b is a rectangular flat plate arranged perpendicularly to the right mounting part 34b, the right pad support part 35b, the right first vertical plate upper part 31i and the right second vertical plate upper part 32i, It fits in the space enclosed by these each part 34b, 35b, 31i, 32i. The right end plate portion 36b is arranged symmetrically with the left end plate portion 36a, and the left end plate portion 36a is a left side mounting portion 34a, a left side pad support portion 35a, a left side first vertical plate upper portion 31d, and a left side second vertical plate. It is welded to the right mounting part 34b, the right pad support part 35b, the right first vertical plate upper part 31i and the right second vertical plate upper part 32i in the same manner as it is welded to the upper part 32d.

  The left-right connecting portion 37 connects the connecting portions 33a and 33b between the left axial connecting portion 33a and the right axial connecting portion 33b. The left-right connecting portion 37 is disposed perpendicular to the left axial connecting portion 33a and the right axial connecting portion 33b, and is disposed perpendicular to the first vertical plate portion 31 and the second vertical plate portion 32. It consists of a flat rectangular plate. The left-right connecting portion 37 is disposed between the upper ends of the left-side axial connecting portion 33a and the right-side axial connecting portion 33b. And the left end edge of the connection part 37 between right and left is welded with respect to the right side surface of the upper end part of the left axial connection part 33a, and the right end part of the connection part 37 between right and left is the upper end part of the right axial connection part 33b. It is welded to the left side.

  The upper sliding pad 8 is provided at the base end portion of the inner boom 14 inserted into the outer boom 12, and the upper sliding pad 8 is disposed at the upper portion of the outer boom 12 when the inner boom 14 moves relative to the outer boom 12 in the axial direction. It slides against the inner surface. Specifically, the upper sliding pad 8 includes a left upper sliding pad 8a and an upper right sliding pad 8b. The upper left sliding pad 8a is stored in the left pad storage portion 24a so as to protrude outward from the outer edges of the left first vertical plate upper portion 31d and the left second vertical plate upper portion 32d. The upper piece 17 is in sliding contact with the inner surface of the upper left portion. The upper right sliding pad 8b is stored in the right pad storage portion 24b so as to protrude outward from the outer edges of the right first vertical plate upper portion 31i and the right second vertical plate upper portion 32i. The upper piece 17 is in sliding contact with the inner surface of the upper right portion.

  Next, the manufacturing method of the telescopic boom 2 by one Embodiment of this invention is demonstrated.

  In the method for manufacturing the telescopic boom 2 according to the present embodiment, each boom member 3 constituting the telescopic boom 2 is formed. That is, the outer boom 12 and the inner boom 14 are formed.

  In the process of forming the outer boom 12, the upper piece 17 and the lower piece 18 are formed by bending a metal plate, respectively, and the upper piece 17 and the lower piece 18 thus formed are welded together to form a cylindrical outer boom. A main body 16 is formed. A component member such as a pad stopper 9 is attached to the inner surface of the lower portion of the distal end portion of the outer boom body 16.

  In the formation process of the inner boom 14, the inner boom body 22 and the end member 24 are formed.

  In the formation process of the inner boom body 22, first, the upper piece 26 and the lower piece 28 are formed by bending a metal plate, respectively. Thereafter, the left and right lower end edges of the upper piece 26 and the left and right upper end edges of the lower piece 28 are brought into contact with each other, and these end edges are welded along the extending direction of the end edges. At this time, welding is performed in a state where the upper piece 26 is disposed with respect to the lower piece 28 so that the base end portion of the lower piece 28 protrudes from the base end portion of the upper piece 26 by the amount of the fitting portion 28e. . In this way, the inner boom body 22 is formed.

  In the step of forming the end member 24, the left first vertical plate portion 31a, the left second vertical plate portion 32a, the left axial connection portion 33a, the left mounting portion 34a, and the left pad support portion 35a constituting the end member 24. , Left end plate portion 36a, right first vertical plate portion 31b, right second vertical plate portion 32b, right axial connecting portion 33b, right mounting portion 34b, right pad support portion 35b, right end plate portion 36b, and left and right connecting portions. The plate members 37 are formed, and the plate members are welded to form the end member 24 having the above structure.

  Next, on the inner surface of the fitting portion 28e of the inner boom body 22 formed as described above, the left first vertical plate lower portion 31c, the right first vertical plate lower portion 31h, and the left second vertical portion of the end member 24 are formed. The left first vertical plate lower side portion 31c, the right first vertical plate lower side portion 31h, and the left second vertical length so that the outer edge portions of the plate lower side portion 32c and the right second vertical plate lower side portion 32h contact each other. The plate lower side portion 32c and the right second vertical plate lower side portion 32h are fitted into the fitting portion 28e. At this time, a surface of the left first vertical plate upper portion 31d facing the side opposite to the left second vertical plate upper portion 32d and a side of the right first vertical plate upper portion 31i opposite to the right second vertical plate upper portion 32i are arranged. The facing surface is in contact with the base end portion of the upper piece 26, the left placement portion 34a is placed on the left upper edge portion 28i of the fitting portion 28e, and the right placement portion 34b is placed on the right upper edge portion of the fitting portion 28e. The end member 24 is arranged so as to be placed on 28j.

  Next, a portion of the end member 24 fitted into the fitting portion 28e is welded to the inner surface of the fitting portion 28e. Specifically, the outer edge portion 31e of the left first vertical plate lower side portion 31c, the outer edge portion 31j of the right first vertical plate lower side portion 31h, the outer edge portion 32e of the left second vertical plate lower side portion 32c, the second right side The outer edge portion 32j of the vertical plate lower side portion 32h, the lower end of the left axial connection portion 33a, and the lower end of the right axial connection portion 33b are welded to the inner surface of the fitting portion 28e. Here, the operator is in the left axial direction from the base end side of the end member 24 when welding the outer edge portion 31e of the left first vertical plate lower side portion 31c and the outer edge portion 31j of the right first vertical plate lower side portion 31h. The outer edge portions 31e and 31j are approached through a space between the connecting portion 33a and the right axial connecting portion 33b, and a portion of the outer edge portions 31e and 31j facing the front end side of the inner boom 14 is a fitting portion. It welds to the inner surface of 28e.

  Further, the left first vertical plate upper portion 31 d and the right first vertical plate upper portion 31 i of the end member 24 are welded to the base end portion of the upper piece 26. Specifically, the left portion of the base end portion of the upper piece 26 is welded along the outer edge of the left first vertical plate upper portion 31d to the surface facing the left second vertical plate upper portion 32d. The right portion of the base end portion of the upper piece 26 is welded along the outer edge of the right first vertical plate upper portion 31i to the surface facing the right second vertical plate upper portion 32i.

  Furthermore, the left upper edge portion 28i of the fitting portion 28e is welded to the lower surface of the left placement portion 34a along the outer edge thereof, and the right upper edge portion 28j of the fitting portion 28e is welded to the lower surface of the right placement portion 34b. Weld along. As described above, the inner boom 14 is formed.

  Next, the left upper sliding pad 8a is stored in the left pad storage portion 24a of the end member 24 of the inner boom 14 formed in this manner, and the upper right pad storage portion 24b of the end member 24 of the inner boom 14 is stored in the upper right. The side sliding pad 8b is stored.

  Then, the inner boom 14 equipped with the upper sliding pads 8a and 8b is inserted into the outer boom 12 from the proximal end portion thereof toward the proximal end side from the distal end side of the outer boom 12. Similarly, the operation of inserting the inner boom 14 as the outer boom 12 and further inserting another inner boom 14 therein is sequentially performed, thereby assembling the telescopic boom 2. The lower sliding pad 6 is installed on the inner surface of the lower portion of the outer boom 12 after the inner boom 14 is inserted into the outer boom 12. The telescopic boom 2 is produced as described above.

  In the present embodiment, the fitting portion 28e of the lower piece 28 of the inner boom body 22 protrudes to the proximal end side of the telescopic boom 2 from the proximal end portion of the upper piece 26 and is fitted into the fitting portion 28e. Since the first vertical plate portion 31 and the second vertical plate portion 32 of the end member 24 are welded to the inner surface of the fitting portion 28e, the lower outer edge portion of the end member 24 is the base end of the lower piece 28. Protruding outside the outer surface of the part can be prevented. As a result, when the base end portion of the inner boom 14 is inserted into the outer boom 12 when the telescopic boom 2 is assembled, the base end portion of the inner boom 14 is provided on the inner surface of the lower portion of the distal end portion of the outer boom 12. Interference with constituent members such as the stopper 9 can be prevented, and the assemblability of the telescopic boom 2 can be improved.

  In the present embodiment, the end member 24 is fitted and welded into the fitting portion 28e of the lower piece 28 of the inner boom body 22, so that the fitting portion 28e and the end member 24 are integrated into the inner side. It can be used to increase the rigidity of the base end portion of the boom 14. That is, in this embodiment, the fitting portion 28e can be used as a part of a stiffening member for increasing the rigidity of the base end portion of the inner boom 14. An end member having a structure that is arranged so as to face the end surface of the base end portion of the conventional inner boom body and that connects two plates disposed at intervals in the axial direction of the inner boom with a connecting portion. Has a portion that connects the lower portions of the two plate bodies so as to substantially follow their outer edges. In this embodiment, the connecting portion 28e is used as a substitute for the portion of the inner boom 14. The rigidity of the base end can be ensured. For this reason, in this embodiment, the part which connects the lower parts of the 1st vertical board part 31 and the 2nd vertical board part 32 so that it may follow along the outer edge of those lower parts from the edge member 24 is abbreviate | omitted. Can be reduced in weight. Therefore, in this embodiment, the rigidity of the proximal end portion of the inner boom 14 can be ensured while reducing the weight of the end member 24.

  Furthermore, in this embodiment, the fitting part 28e protrudes to the base end side of the telescopic boom 2 from the base end part of the upper piece 17, and the left first vertical plate upper part 31d located above the fitting part 28e. A left pad storage portion 24a for storing the left upper sliding pad 8a is provided between the left first vertical plate upper portion 32d and the right second vertical plate upper portion 31d. Since the right pad storage part 24b for storing the upper right sliding pad 8b is provided between the second vertical plate upper part 32i and the end member 24 is fitted in the fitting part 28e, The upper left sliding pad 8 a and the upper right sliding pad 8 b can be held at appropriate positions in the base end portion of the boom 14 so as to be in sliding contact with the upper inner surface of the outer boom 12.

  Further, in the present embodiment, the left first vertical plate portion 31a has a left first vertical plate lower side portion 31c that is fitted into the fitting portion 28e and welded to the inner surface of the fitting portion 28e. Since the first vertical plate portion 31b has the right first vertical plate lower side portion 31h fitted into the fitting portion 28e and welded to the inner surface of the fitting portion 28e, for example, only the second vertical plate portion 32 is fitted. Compared with the case where it is welded to the inner surface of the portion 28e, the coupling strength between the end member 24 and the fitting portion 28e can be increased, and the proximal end portion of the inner boom 14 comprising the end member 24 and the fitting portion 28e. The rigidity of can be further increased.

  In the present embodiment, the left mounting portion 34a of the end member 24 and the left upper edge portion 28i of the fitting portion 28e are welded and the right mounting portion 34b of the end member 24 and the fitting portion 28e are welded. Since the right upper edge portion 28j is welded, the coupling strength between the end member 24 and the fitting portion 28e can be further increased, and the base of the inner boom 14 including the end member 24 and the fitting portion 28e can be increased. The rigidity of the end can be further increased.

  In the present embodiment, the left first vertical plate portion 31a, the left second vertical plate portion 32a, and the left axial connection portion 33a, the right first vertical plate portion 31b, the right second vertical plate portion 32b, and the right axial direction. Since the connecting portion 33b is arranged with a gap left and right, the left first vertical plate portion 31a and the right first vertical plate portion 31b are welded to the inner surface of the fitting portion 28e from the proximal end side of the inner boom 14. Through the space between the left and right members, it is possible to approach the outer edge portion 31e of the left first vertical plate lower side portion 31c and the outer edge portion 31j of the right first vertical plate lower side portion 31h. Therefore, the left first vertical plate lower portion 31c is hidden behind the left second vertical plate lower portion 32c in the fitting portion 28e, and the right first vertical plate lower portion 31h is the right second vertical plate. Even if it is hidden behind the lower side portion 32h, welding work is performed on the inner surface of the fitting portion 28e of the outer edge portion 31e of the left first vertical plate lower side portion 31c and the outer edge portion 31j of the right first vertical plate lower side portion 31h. It can be done easily.

  Further, in the present embodiment, since the left axial connection portion 33 a and the right axial connection portion 33 b of the end member 24 are connected by the left-right connection portion 37, the first left vertical plate portion of the end member 24. 31a, the left second vertical plate portion 32a and the left axial connection portion 33a, and the right first vertical plate portion 31b, the right second vertical plate portion 32b, and the right axial connection portion 33b of the end member 24 are laterally spaced. Even if it arrange | positions open, those left and right members can be integrated via the connection part 37 between right and left, and the rigidity of the edge part member 24 can be ensured.

  In the present embodiment, in the step of forming the inner boom 14, the outer edge portion 31e of the left first vertical plate lower portion 31c and the right first vertical plate lower portion 31h are formed on the inner surface of the fitting portion 28e of the lower piece 28. The outer edge portion 31j, the outer edge portion 32e of the left second vertical plate lower side portion 32c, and the outer edge portion 32j of the right second vertical plate lower side portion 32h contact each of the vertical plate lower side portions 31c, 31h, 32c, 32h are fitted into the fitting portion 28e, and then the outer edge portions 31e, 31j, 32e, 32j of the fitted vertical plate lower side portions 31c, 31h, 32c, 32h are attached to the inner surface of the fitting portion 28e. Since welding is performed, it is possible to reduce the work load related to the welding work. Specifically, in the present embodiment, on the inner surface of the fitting portion 28e, the outer edge portion 31e of the left first vertical plate lower portion 31c of the end member 24, the outer edge portion 31j of the right first vertical plate lower portion 31h, The vertical plate lower side portions 31c, 31h, 32c and 32h are fitted so that the outer edge portion 32e of the left second vertical plate lower side portion 32c and the outer edge portion 32j of the right second vertical plate lower side portion 32h come into contact with each other. Since the end member 24 can be temporarily fixed to the fitting portion 28e by fitting into the fitting portion 28e, the state in which the end member 24 is accurately positioned with respect to the fitting portion 28e can be easily maintained. In this state, the outer edge portions 31e, 31j, 32e, 32j of the vertical plate lower side portions 31c, 31h, 32c, 32h can be welded to the inner surface of the fitting portion 28e. For this reason, the work burden concerning welding work can be reduced.

  Moreover, in this embodiment, the dimension (left side 1st vertical board lower side part) of the left-right direction of the part fitted in the fitting part 28e among the 1st vertical board part 31 and the 2nd vertical board part 32 of the edge part member 24 is shown. (Dimension between the left end of 31c and the right end of the right first vertical plate lower side portion 31h and dimension between the left end of the left second vertical plate lower side portion 32c and the right end of the right second vertical plate lower side portion 32h) Even when there is a slight difference between the left and right inner dimensions of the fitting portion 28e, the left and right side plate portions 28g and 28h of the fitting portion 28e are displaced in the left and right direction to change the left and right sides of the fitting portion 28e. The internal dimension in the direction can be adjusted to match the horizontal dimension of the portion of the first vertical plate portion 31 and the second vertical plate portion 32 that fits in the fitting portion 28e.

  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, in the manufacturing process of the telescopic boom 2, the fitting process for fitting the end member 24 into the fitting portion 28 e and the welding process for welding the fitted end member 24 to the inner surface of the fitting portion 28 e include the upper piece 26. It may be performed prior to the step of forming the inner boom body 22 for welding the lower piece 28 and the lower piece 28 together. Specifically, in the step of fitting the end member 24 into the fitting portion 28e, the lower left and right first vertical plates of the end member 24 are placed in the fitting portion 28e of the lower piece 28 that is not welded to the upper piece 26. The side portions 31c and 31h and the left and right second vertical plate lower side portions 32c and 32h are fitted, and then the first vertical plate lower side portions 31c and 31h and the second vertical plate lower side of the end member 24 with respect to the fitting portion 28e. In the welding process of the portions 32c and 32h, the outer edge portion 31e of the left first vertical plate lower side portion 31c fitted into the fitting portion 28e of the lower piece 28 which is not welded to the upper piece 26, the lower right first vertical plate The outer edge portion 31j of the side portion 31h, the outer edge portion 32e of the left second vertical plate lower side portion 32c, and the outer edge portion 32j of the right second vertical plate lower side portion 32h may be welded to the inner surface of the fitting portion 28e.

  According to this configuration, before the lower piece 28 is welded to the upper piece 26, the first vertical plate lower side portions 31 c and 31 h and the second vertical plate of the end member 24 are fitted into the fitting portion 28 e of the lower piece 28. Since the lower portions 32c and 32h are fitted and welded, the horizontal dimension of the portion to be fitted in the fitting portion 28e (the left end of the left first vertical plate lower portion 31c and the lower portion of the right first vertical plate) The dimension between the right end of 31h and the dimension between the left end of the left second vertical plate lower side portion 32c and the right end of the right second vertical plate lower side portion 32h) are the inner dimensions in the left-right direction of the fitting portion 28e. When slightly different, the inner dimension in the left-right direction of the fitting portion 28e can be easily adjusted according to the dimension in the left-right direction of the portion to be fitted. Specifically, after the lower piece 28 is welded to the upper piece 26, the first vertical plate lower side portions 31c and 31h and the second vertical plate lower side portions 32c and 32h are fitted into the fitting portion 28e of the lower piece 28. In the case of welding with the upper piece 26, the upper left and right ends of the lower piece 28 are constrained by the upper piece 26, so that the left side plate portion 28g and the right side plate portion 28h of the fitting portion 28e are not easily deformed in the left and right direction. It is difficult to adjust the inner dimension of the portion 28e in the left-right direction. On the other hand, in this configuration, when the first vertical plate lower side portions 31c and 31h and the second vertical plate lower side portions 32c and 32h of the end member 24 are fitted in the fitting portion 28e and welded, Since the lower piece 28 is not welded to the upper piece 26, the upper ends of the left and right sides of the lower piece 28 are not constrained, and the left side plate portion 28g and the right side plate portion 28h of the fitting portion 28e are easily displaced in the left and right direction. Thus, the inner dimension in the left-right direction of the fitting portion 28e can be easily adjusted to match the dimension in the left-right direction of the portion of the end member 24 fitted into the fitting portion 28e.

  In the above embodiment, the left first vertical plate lower portion 31c, the right first vertical plate lower portion 31h, the left second vertical plate lower portion 32c, and the right second vertical plate lower portion fitted in the fitting portion 28e. Of the outer edge portions 31e, 31j, 32e, and 32j of the portion 32h, only the portions that contact the inner surface of the curved portion 28f of the fitting portion 28e are welded, and contact the inner surfaces of the left and right side plate portions 28g and 28h of the fitting portion 28e. The part may not be welded.

  Moreover, in the said form, you may abbreviate | omit welding with the outer edge part 31e of the left side 1st vertical board lower side part 31c, the outer edge part 31j of the right side 1st vertical board lower side part 31h, and the inner surface of the fitting part 28e.

  Further, the left first vertical plate lower portion 31c may be omitted from the left first vertical plate portion 31a, and the right first vertical plate lower portion 31h may be omitted from the right first vertical plate portion 31b.

  Further, the welding between the left mounting portion 34a and the left upper edge portion 28i of the fitting portion 28e and the welding between the right mounting portion 34b and the right upper edge portion 28j of the fitting portion 28e may be omitted.

  Further, the left side mounting portion 34a and the right side mounting portion 34b may be omitted from the end member 24.

  Further, the left end plate portion 36a and the right end plate portion 36b may be omitted from the end member 24.

  Further, the left-right connecting portion 37 may be omitted from the end member 24.

  Further, the left-right connecting portion is not limited to the above-described one, and may have any configuration as long as the constituent members of the end members arranged separately on the left and right are connected to each other. May be. For example, the left-right connecting portion may be a columnar member or the like.

  Moreover, the 1st vertical board part may consist of one board body which is not divided | segmented into right and left, and the 2nd vertical board part consists of 1 board body which is not divided | segmented into right and left similarly. Also good.

  Moreover, the part which connects them may be provided between the upper end parts of the left side 1st vertical board part 31a and the right side 1st vertical board part 31b, and the left side 1st vertical board part 31a and the 1st right side 1st. Between the lower end portions of the vertical plate portion 31b, a portion connecting them may be provided.

  Moreover, between the upper ends of the left second vertical plate portion 32a and the right second vertical plate portion 32b, a portion for connecting them may be provided. The left second vertical plate portion 32a and the right second plate Between the lower end parts of the vertical plate part 32b, a part for connecting them may be provided.

  Further, the left first vertical plate portion, the left second vertical plate portion, and the left axial connection portion may be integrally formed by bending one plate material, and the right first vertical plate portion, right side Similarly, the second vertical plate portion and the right axial direction connecting portion may be integrally formed by bending one plate material.

  Further, the left second vertical plate portion and the left axial connection portion may be integrally formed by bending one plate material, and the right second vertical plate portion and the right axial connection portion are 1 The sheet material may be formed integrally by bending.

2 Telescopic boom 8 Upper sliding pad 12 Outer boom 14 Inner boom 22 Inner boom body 24 End member 24a Left pad storage 24b Right pad storage 26 Upper piece 28 Lower piece 28e Fitting 28i Left upper edge 28j Upper right Edge 31 First vertical plate portion 31a Left first vertical plate portion 31b Right first vertical plate portion 32 Second vertical plate portion 32a Left second vertical plate portion 32b Right second vertical plate portion 33 Axial connecting portion 33a Left side shaft Direction connecting portion 33b right axial connecting portion 34a left mounting portion 34b right mounting portion 37 left and right connecting portion

Claims (7)

A telescopic boom that can be raised and lowered in a crane and configured to be telescopic,
An outer boom formed in a tubular shape;
An inner boom that is inserted into the outer boom and is axially movable relative to the outer boom;
An upper slide provided at the base end portion of the inner boom inserted into the outer boom and sliding with respect to the inner surface of the upper portion of the outer boom when the inner boom moves relative to the outer boom. With a pad,
The inner boom has an inner boom body formed in a cylindrical shape, and an end member that is attached to the proximal end portion of the inner boom body and increases the rigidity of the proximal end portion of the inner boom body,
The inner boom body is formed to have an upper piece that constitutes an upper part in a cross section orthogonal to the axial direction of the inner boom body, and a curved shape with an upper part opened in the cross section, and forms an opening in the upper part A lower piece coupled to the lower end of the upper piece at the upper ends of the left and right sides,
At the base end portion of the lower piece, a fitting portion is formed that protrudes toward the base end side of the telescopic boom from the base end portion of the upper piece, and into which the end member is fitted,
The end member is disposed so as to be orthogonal to the axial direction of the inner boom body, and is disposed so as to face the proximal end portion of the upper piece, and is welded to the proximal end portion of the upper piece. 1 vertical plate portion, and is fitted into the fitting portion in a state of being arranged in parallel with the first vertical plate portion with a gap on the proximal end side of the telescopic boom with respect to the first vertical plate portion, A second vertical plate portion welded to the inner surface of the fitting portion, an axial connecting portion connecting the first vertical plate portion and the second vertical plate portion therebetween, the first vertical plate portion, and the A telescopic boom having a pad storage portion that is provided between portions of the second vertical plate portion that are positioned above the fitting portion and that stores the upper sliding pad.   The telescopic boom according to claim 1, wherein the first vertical plate portion has a portion fitted into the fitting portion and welded to an inner surface of the fitting portion. The fitting portion has left and right upper edge portions that form an opening in the upper portion of the fitting portion, and the left and right upper edge portions extend along the axial direction of the inner boom body,
The end member is coupled to the first vertical plate portion and the second vertical plate portion, and is placed on the upper left edge portion of the left side and welded to the upper edge portion; The first vertical plate portion and the second vertical plate portion are coupled to each other and have a right-side placement portion that is placed on the upper edge portion of the right side and welded to the upper edge portion. The telescopic boom described. The first vertical plate portion is a left first vertical plate portion and a right first vertical plate portion that are spaced apart from each other with respect to the center in the horizontal direction in a cross section orthogonal to the axial direction of the inner boom body. And consist of
The second vertical plate portion includes a left second vertical plate portion and a right second vertical plate portion that are spaced apart from each other on the left and right with respect to the center in the left-right direction.
The axial connection portion includes a left axial connection portion that connects the left first vertical plate portion and the left second vertical plate portion therebetween, the right first vertical plate portion, and the right second vertical plate. And the left axial connection portion and the right axial connection portion are spaced apart from each other with respect to the center in the left-right direction. The telescopic boom according to claim 2.   The telescopic boom according to claim 4, wherein the end member has a left-right connecting portion that connects the connecting portions between the left-side axial connecting portion and the right-side axial connecting portion. A method of manufacturing the telescopic boom according to any one of claims 1 to 5,
An outer boom forming step for forming the outer boom;
An inner boom forming step for forming the inner boom;
Extending and retracting the telescopic boom by inserting the inner boom formed in the inner boom forming step from the proximal end portion into the outer boom formed in the outer boom forming step from the distal end side to the proximal end side of the outer boom. A boom assembly process,
The inner boom forming step includes an inner boom main body forming step of forming the inner boom main body by welding the lower end of the upper piece and the upper end of the lower piece, and the end on the inner surface of the fitting portion of the lower piece. A fitting step of fitting the second vertical plate portion into the fitting portion so that an outer edge portion of the second vertical plate portion of the member is in contact; and a step of fitting the second vertical plate portion into the fitting portion. A second vertical plate portion welding step of welding the outer edge portion to the inner surface of the fitting portion, and a first vertical plate portion welding step of welding the first vertical plate portion of the end member to the base end portion of the upper piece. A method for manufacturing a telescopic boom.   The fitting step and the second vertical plate portion welding step are performed prior to the inner boom body forming step, and in the fitting step, the end is placed in the fitting portion of the lower piece that is not welded to the upper piece. An outer edge of the second vertical plate portion fitted into the fitting portion of the lower piece that is not welded to the upper piece in the second vertical plate portion welding step. The manufacturing method of the telescopic boom of Claim 6 which welds a part to the inner surface of the fitting part.

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