JP5595242B2 - Crane post manufacturing method - Google Patents

Description

  The present invention relates to a crane post manufacturing method using welding and a crane post manufactured by welding.

  A crane (hoist) is a device that lifts and carries a cargo handling object. A crane mounts a hoisting device, a lifting device and the like on a structure called a crane post and attaches a jib. For example, Patent Document 1 describes a method of manufacturing a deck crane in which a main body of a deck crane is assembled in a factory where a large crane is arranged outdoors adjacent to a building having a small crane.

JP 2009-196800 A, (0007)

  In general, a crane post is manufactured by combining plate-like members. Although patent document 1 is described about assembling the main body of a deck crane, it is not mentioned about manufacturing the crane post itself of a deck crane. An object of this invention is to manufacture a high quality crane post efficiently.

In order to solve the above-described problems and achieve the object, a method for manufacturing a crane post according to the present invention provides a method for manufacturing a crane post having a plurality of ridgelines and a polygonal cross section. A material cutting step of cutting out a plurality of components, a bending step of forming the ridge line on the component by bending the cut-out component, and the crane post obtained from the bent component The welding target portions of the left outer plate and the right outer plate are opposed to each other, the longitudinal direction of the left outer plate and the right outer plate is along the horizontal direction, and the rear side of the crane post is the lower side in the vertical direction. A first part of welding the part to be welded on the rear side of the crane post from the inner side surrounded by the left outer plate and the right outer plate. And contacting step, the rotation step of rotating the left outer plate and the right side outer plate after welding, comprising a second welding step for welding the remaining welded portion, and before the component placing step, the A plate joining step for manufacturing the left outer plate and the right outer plate by welding parts subjected to bending, and the left outer plate after the plate joining step is completed and before the component installation step. And a reinforcing member attaching step of attaching a reinforcing member to the top side of the right outer plate .

In this method of manufacturing a crane post, the outer plate is arranged and welded so that the longitudinal direction of the outer plate constituting the crane post is along the horizontal direction, and the welded structure is rotated. If the outer plate is arranged and welded so that the longitudinal direction of the outer plate is aligned with the horizontal direction, automatic welding is performed when there is no cause (for example, opening of the driver's seat) that interrupts welding in the longitudinal direction of the outer plates. Can be efficiently welded. As a result, a high quality crane post can be manufactured efficiently. In addition, when the reinforcing member is attached to the left outer plate and the right outer plate at the stage of manufacturing the left outer plate and the right outer plate, the reinforcing member is attached to the cylindrical structure in which the left outer plate and the right outer plate are joined. Work becomes easy.

In order to solve the above-described problems and achieve the object, a method for manufacturing a crane post according to the present invention provides a method for manufacturing a crane post having a plurality of ridgelines and a polygonal cross section. A material cutting step of cutting out a plurality of components, a bending step of forming the ridge line on the component by bending the cut-out component, and the crane post obtained from the bent component The welding target portions of the left outer plate and the right outer plate are opposed to each other, the longitudinal direction of the left outer plate and the right outer plate is along the horizontal direction, and the rear side of the crane post is the lower side in the vertical direction. A first part of welding the part to be welded on the rear side of the crane post from the inner side surrounded by the left outer plate and the right outer plate. Includes a contact step, the top base member attaching step of attaching the top base member to the top side of the left outside panel and the right side outer plate after welding, and a second welding step for welding the remaining welded portion, and Before the component installation step, the bent parts are welded together to produce the left outer plate and the right outer plate, the plate joining step is completed, and the component installation Before the step, a reinforcing member attaching step of attaching a reinforcing member to the top side of the left outer plate and the top side of the right outer plate is characterized.

In this method of manufacturing a crane post, the outer plate is arranged and welded so that the longitudinal direction of the outer plate constituting the crane post is along the horizontal direction, and the welded structure is rotated. If the outer plate is arranged and welded so that the longitudinal direction of the outer plate is aligned with the horizontal direction, automatic welding is performed when there is no cause (for example, opening of the driver's seat) that interrupts welding in the longitudinal direction of the outer plates. Can be efficiently welded. As a result, a high quality crane post can be manufactured efficiently. Moreover, since the top base member is attached to the structure in a state where the welded structure is disposed so that the longitudinal direction thereof is along the horizontal direction, the attachment work is facilitated. In addition, when the reinforcing member is attached to the left outer plate and the right outer plate at the stage of manufacturing the left outer plate and the right outer plate, the reinforcing member is attached to the cylindrical structure in which the left outer plate and the right outer plate are joined. Work becomes easy.

  In the housing of the deck crane described in Patent Document 1 described above, since the load from the wire rope that suspends the cargo handling object or the wire rope that lifts the jib acts on the top, it is necessary to ensure the strength of the top. In Patent Document 1, there is no description or suggestion about this point, and there is room for improvement. The crane post which concerns on this invention makes it the subject to ensure the intensity | strength of a top part. And since the crane post which concerns on this invention can fully ensure the intensity | strength of the top part of a crane post by the said structure, it can fully endure the load resulting from the tension | pulling force of the wire rope for luggage | lifts and a lift.

  The present invention can efficiently produce a high quality crane post.

FIG. 1 is an overall view of a ship equipped with a crane according to this embodiment. FIG. 2 is an overall configuration diagram illustrating the configuration of the crane according to the present embodiment. FIG. 3 is a side view of the crane post according to the present embodiment. FIG. 4 is a plan view of the crane post according to the present embodiment as viewed from the top side. FIG. 5 is a flowchart showing the steps of the crane post manufacturing method according to the present embodiment. FIG. 6 is a view for explaining the crane post manufacturing method according to the present embodiment. FIG. 7 is a view for explaining the crane post manufacturing method according to the present embodiment. FIG. 8 is a diagram for explaining a method of manufacturing a crane post according to the present embodiment. FIG. 9 is a diagram for explaining a method for manufacturing a crane post according to the present embodiment. FIG. 10 is a view for explaining the crane post manufacturing method according to the present embodiment. FIG. 11 is a diagram for explaining a method of manufacturing a crane post according to the present embodiment. FIG. 12 is a view for explaining the crane post manufacturing method according to the present embodiment. FIG. 13 is a view for explaining the crane post manufacturing method according to the present embodiment. FIG. 14 is a view for explaining the crane post manufacturing method according to the present embodiment. FIG. 15 is a view for explaining the crane post manufacturing method according to the present embodiment. FIG. 16 is a view for explaining the crane post manufacturing method according to the present embodiment. FIG. 17 is a perspective view showing a rotating jig that rotates the left outer plate and the right outer plate. FIG. 18 is a perspective view showing a crane post according to a modification of the present embodiment. FIG. 19 is a diagram illustrating a part of a manufacturing process of a crane post according to a modification of the present embodiment. FIG. 20 is a diagram illustrating a part of a manufacturing process of a crane post according to a modification of the present embodiment.

DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined. In the following, a jib crane will be described as an example of a crane, but the application target of the present invention is not limited to a jib crane. A jib crane is a cargo handling machine that is installed on the deck of a cargo ship or at a port facility, and is used for loading cargo to be transported by sea into a cargo ship or unloading cargo from a cargo ship.

  FIG. 1 is an overall view of a ship equipped with a crane according to this embodiment. The crane 1 is mounted on the deck 101 of the ship 100 and is used when the cargo handling object C is lowered from the ship 100 or when the cargo handling object C is loaded onto the ship 100. In the present embodiment, the ship 100 is a cargo ship and has four cranes 1. The number of cranes 1 that the ship 100 has is not limited to four. Next, the crane 1 will be described.

  FIG. 2 is an overall configuration diagram illustrating the configuration of the crane according to the present embodiment. The crane 1 includes a crane post 2, a hoisting device 3, a lifting device 4, a turning device 5, and a jib 6. In the present embodiment, the hoisting device 3 and the lifting / lowering device 4 are integrally formed. The crane post 2 includes a hoisting device 3, a lifting device 4, a turning device 5, and a jib 6. The crane post 2 is installed on a gantry 102 provided in the ship 100. The crane post 2 can rotate about an axis Z orthogonal to the support surface of the gantry 102 provided on the deck 101 of the ship 100. On the jib 6 side of the crane post 2, an operator cab DC in which equipment for operating the crane 1 is arranged is provided.

  The jib 6 is a rod-like member and has a pulley 7 at the tip 6Tt. The end of the jib 6 opposite to the tip 6Tt is a mounting end 6Tl. The jib 6 has an attachment end 6Tl attached to the crane post 2. The jib 6 can swing around the attachment portion of the attachment end 6Tl. The swing direction of the jib 6 is the direction indicated by the arrow U in FIG. A luggage wire rope 8 for hanging a cargo handling object is hung on the pulley 7. A loading hook 10 for hanging a cargo handling object is attached to one end of the luggage wire rope 8. The other end of the load wire rope 8 is connected to and wound around the hoisting drum 3D of the hoisting device 3.

  The hoisting device 3 rotates the hoisting drum 3 </ b> D by a power generation source and winds the load wire rope 8. Further, the hoisting device 3 unwinds the wound luggage wire rope 8. The movement of the hoisting drum 3D of the hoisting device 3 to wind up the wire rope 8 for luggage is referred to as hoisting, and the movement of feeding is referred to as lowering. In the present embodiment, both movements are collectively referred to as winding. When the hoisting device 3 winds the wire rope 8 for luggage, the load hook 10 moves in a direction parallel to the vertical direction (direction indicated by an arrow Y in FIG. 2).

  The upright device 4 is a device for raising the jib 6. The lifting device 4 has a lifting drum 4D around which a lifting wire rope 11 is wound. The up-and-down wire rope 11 is connected between the tip 6Tt of the jib 6 and the attachment end 6Tl. The jib 6 faces upward (opposite to the vertical direction) when the elevating device 4 winds the elevating wire rope 11, and faces downward (vertical direction) when the elevating wire rope 11 is unwound. The turning device 5 is a device for turning the crane post 2 around an axis Z orthogonal to the support surface of the gantry 102. The direction in which the crane post 2 turns is the direction indicated by the arrow R in FIG.

  A top base member 12 is attached to the top 2T of the crane post 2, that is, the side opposite to the side of the crane post 2 attached to the gantry 102. The top base member 12 has a pulley 13 around which the wire rope 8 for luggage is hung and a pulley 14 around which the wire rope 11 for lifting is hung. The wire rope 8 for luggage is wound around the pulley 13 and the pulley 7 and wound around the winding drum 3D. The hoisting wire rope 11 is wound around the pulley 14 and wound around the hoisting drum 4D.

  A beam 15 is attached to the top 2T of the crane post 2. The beam 15 is a plate-like and substantially U-shaped member. In the present embodiment, a plurality of beams 15 are attached from the attachment side (front side) 2F of the jib 6 of the crane post 2 to the opposite side (rear side) 2R of the attachment side 2F, and are attached to the front side 2F of the crane post 2. The rear side 2R is connected. That is, the beam 15 is fixed to the inside of the top of the crane post 2 in the front-rear direction of the crane post 2. The top base member 12 is fixed to the beam 15 and the crane post 2. The top base member 12 that supports the pulleys 13 and 14 supports the pulling force of the load wire rope 8 and the lifting wire rope 11 through the pulleys 13 and 14. For this reason, a large load acts on the top 2T of the crane post 2 to which the top base member 12 is attached. However, by providing the beam 15 in the front-rear direction of the top 2T of the crane post 2, the crane post 2 is sufficient for the load. Can withstand.

  FIG. 3 is a side view of the crane post according to the present embodiment. FIG. 4 is a plan view of the crane post according to the present embodiment as viewed from the top side. The crane post 2 is a structure having a substantially octagonal truncated pyramid shape. However, the crane post 2 is not limited to this, for example, a quadrangular pyramid shape, a hexagonal pyramid shape, a nine pyramid shape, an octagonal prism shape, a quadrangular prism shape, etc. The structure may be a columnar or frustum-shaped structure having a parallel direction (that is, a cross section perpendicular to the longitudinal direction).

  The crane post 2 has an outer cylinder 20 in which a plurality of outer plates 21F, 21R, 22F, and 22R each having a ridge line (bent portion) B are joined by welding. The crane post 2 has a plurality of beams 15 attached to the top 2T from the front side 2F toward the rear side 2R. The outer cylinder 20 is manufactured by welding a left outer plate 21 and a right outer plate 22. Here, the left outer plate 21 is manufactured by welding the outer plates 21F and 21R, and the right outer plate 22 is manufactured by welding the outer plate 22F and the outer plate 22R. A symbol WL shown in FIG. 4 is a weld line.

  The outer plates 21F and 22F are arranged on the front side 2F of the crane post 2, and the outer plates 21R and 22R are arranged on the rear side 2R of the crane post 2. In the present embodiment, the left outer plate 21 is arranged on the left side from the rear side 2R to the front side 2F of the crane post 2 (outer cylinder 20), and the right outer plate 22 is arranged on the right side. Next, a method for manufacturing the crane post 2 will be described.

  FIG. 5 is a flowchart showing the steps of the crane post manufacturing method according to the present embodiment. 6-16 is a figure for demonstrating the manufacturing method of the crane post which concerns on this embodiment. When the crane post 2 shown in FIGS. 2 and 3 is manufactured by the crane post manufacturing method according to the present embodiment, the outer plates 21F, 21R, 22F, and 22R of the crane post 2 are formed from the plate material as shown in FIG. A plurality of parts 21Fp, 21Rp, 22Fp, and 22Rp are cut out (step S101). Step S101 corresponds to a material cutting process. The components 21Fp, 21Rp, 22Fp, and 22Rp are cut out from, for example, a steel plate. The components 21Fp, 21Rp, 22Fp, and 22Rp are plate materials having a joining position at a plane position where the ridgeline B having a polygonal cross section is removed in the axial direction (longitudinal direction) of the crane post 2.

  A two-dot chain line Bpl in FIG. 6 is a position for bending the respective components 21Fp, 21Rp, 22Fp, and 22Rp. Hereinafter, Bpl is referred to as a press line. After the bending of each component 21Fp, 21Rp, 22Fp, 22Rp is completed, the press line Bpl becomes the ridgeline B of the outer plates 21F, 21R, 22F, 22R shown in FIGS. As shown in FIG. 1, the crane post 2 includes the cab DC, and therefore, the parts 21Fp and 22Fp are formed with notches CU that serve as windows of the cab DC.

  Next, as shown in FIG. 7, the cut parts 21Fp, 21Rp, 22Fp, and 22Rp are bent (step S102). Step S102 corresponds to a bending process. A press line Bpl in FIG. 7 indicates a bending position. A bending process is a process of forming the ridgeline B of the crane post 2 of the polygonal cross section shown in FIG. 3 by performing a press bending process along the press line Bpl shown in FIG. There are one or more locations for press bending per part. This differs depending on the number of ridge lines B determined by the cross-sectional shape of the crane post 2 to be manufactured and used. By the bending process, as shown in FIG. 8, the components 21Fp, 21Rp, 22Fp, and 22Rp become outer plates 21F, 21R, 22F, and 22R, respectively. The press line Bpl shown in FIG. 6 becomes the ridgeline B of the outer plates 21F, 21R, 22F, 22R. When the outer plates 21F, 21R, 22F, and 22R are welded in a welding process that will be described later and the crane post 2 having a polygonal cross section shown in FIG. 3 is completed, the press line Bpl becomes the ridge line B of the crane post 2 having a polygonal cross section. .

  When the outer plates 21F, 21R, 22F, and 22R are completed, as shown in FIGS. 9 and 10, the parts that are bent to form the ridgeline B, that is, the outer plates 21F and 21R and the outer plates 22F and 22R are joined together. Each is welded to manufacture the left outer plate 21 and the right outer plate 22 (step S103). Step S103 corresponds to a plate joining step. As shown in FIG. 11, in the plate joining step, a backing 51 is provided on the opposite side of the groove HT provided at the butted portion of the outer plates 21F and 21R and the groove HT provided at the butted portion of the outer plates 22F and 22R. And the butt portion is welded (butt welding) using the welding torch 50. The groove shape is not limited to the V groove as shown in the figure, and may be a groove other than this.

  In the present embodiment, submerged arc welding is used in the plate joining step, but the welding technique is not limited to this (the same applies hereinafter). For example, when manufacturing a crane post having a square shape in plan view, it is sufficient to join two outer plates bent in a U-shape by welding. For this reason, the method for manufacturing a crane post according to the present embodiment does not necessarily require the plate joining step depending on the shape of the crane post 2 to be manufactured.

  In the plate joining step, the longitudinal directions of the outer plates 21F, 21R, 22F, and 22R are arranged in a posture along the horizontal direction and are welded. Usually, when a plate material is welded at each end portion (corner portion), a large amount of distortion warping occurs, so that it takes time to remove the distortion, and the work efficiency is lowered and it is difficult to maintain quality. In the present embodiment, in the plate joining step, the plane portions of the outer plate 21F and the outer plate 21R and the plane portions of the outer plate 22F and the outer plate 22R are welded. In this way, since warping of distortion is reduced, the time for removing distortion is shortened, and a reduction in work efficiency is suppressed. Moreover, since distortion warping is suppressed, the deterioration of the quality of the crane post 2 can also be suppressed.

  Through the plate joining step, the outer plates 21F and 21R are joined to complete the left outer plate 21, and the outer plates 22F and 22R are joined to complete the right outer plate 22. Next, as shown in FIG. 12, the beam 15 as a reinforcing member is attached to the top side of the left outer plate 21 and the top side of the right outer plate 22 (step S104). When the beam 15 is attached to the left outer plate 21 and the right outer plate 22, the left outer plate 21 and the right outer plate 22 are positioned upward as shown in FIGS. 9 and 10 described above. It is preferable to face the other side.

  The top side of the left outer plate 21 and the right outer plate 22 is the top 2T side of the crane post 2 shown in FIG. The left outer plate 21 and the right outer plate 22 each have one beam 15. For this reason, the crane post 2 manufactured by connecting the left outer plate 21 and the right outer plate 22 has two beams 15. The number of beams 15 included in the crane post 2 is not limited to two, and can be appropriately changed depending on the specifications of the crane post 2.

  One beam 15 is welded to the outer plates 21F and 21R of the left outer plate 21, and connects the two. The other beam 15 is welded to the outer plates 22F and 22R of the right outer plate 22 to connect the two. Thus, one beam 15 connects the front side 2F and the rear side 2R of the left outer plate 21, and the other beam 15 connects the front side 2F and the rear side 2R of the right outer plate 22. FIG. 13 shows a state in which the front side 2F and the rear side 2R of the left outer plate 21 are connected by the beam 15 connecting the outer plates 21F and 21R.

  Next, as shown in FIG. 14, the left outer plate 21 obtained from the bent parts 21Fp and 21Rp and the right outer plate 22 obtained from the bent parts 22Fp and 22Rp are to be welded. Make the parts face each other. And these are installed on the surface plate 52 so that the longitudinal direction of the left side outer plate 21 and the right side outer plate 22 may follow a horizontal direction, and a welding object part may become a vertical direction lower side (step S105). Step S105 corresponds to a component installation process (large assembly process). The portion to be welded is a portion where the groove HT of the left outer plate 21 and the right outer plate 22 is formed.

  In the component installation step, a portion to be subjected to the main welding (welding not temporary welding) is arranged on the surface plate 52 side, that is, on the lower side in the vertical direction. As the portion to be subjected to the main welding first, a portion that can secure a longer weld line is selected. This is because by making the weld line longer, the strength of the crane post 2 (temporary assembly) in the course of manufacture is ensured and automatic welding is used as much as possible. In the present embodiment, the outer plates 21R and 22R on the side opposite to the outer plates 21F and 22F provided with the notches CU (the rear side of the crane post 2) are set as the surface plate 52 side. That is, the outer plates 21R and 22R are first finally welded. In this example, a backing 51 is disposed between the surface plate 52 and the left outer plate 21 and the right outer plate 22. The outer plates 21F and 22F provided with the notch CU are interrupted by the notch CU, so that it is difficult to secure the strength of the temporary assembly, and automatic welding is interrupted by the notch CU. Since the working efficiency cannot be improved sufficiently, the outer plates 21R and 22R are first finally welded.

  When the left outer plate 21 and the right outer plate 22 are installed on the surface plate 52, the welding target portion is welded (step S106). Step S106 corresponds to the first welding process. In the welding process, first, the outer plate 21R and the outer plate 22R are temporarily welded, and then the side of the left outer plate 21 and the right outer plate 22 opposite to the surface plate 52, that is, the outer plates 21F and 22F side. Temporary welding is performed, and the surface plate 52 side of the left outer plate 21 and the right outer plate 22, that is, the outer plates 21R and 22R are fully welded over the entire longitudinal direction, and both are joined. For this reason, in the component installation step described above, the left outer plate 21 and the right outer plate 22 are installed such that the wider side of the groove HT of the outer plates 21R and 22R is on the upper side in the vertical direction. Then, from the inside surrounded by the left outer plate 21 and the right outer plate 22, the outer plate 21R of the left outer plate 21 and the outer plate 22R of the right outer plate 22 are welded (main welding) by the welding torch 50.

  The outer plates 21F and 22F have notches CU, but the outer plates 21R and 22R have no notches CU. For this reason, it is possible to weld a portion to be welded (a portion where the groove HT is provided) over the entire longitudinal direction of the outer plates 21R and 22R by automatic welding. As a result, welding work is facilitated and the productivity of the crane post 2 is improved. Further, by welding the outer plates 21R and 22R having no notch CU first, the weld line WL shown in FIG. 15 becomes longer than welding the outer plates 21F and 22F having the notch CU. For this reason, since the strength of the structure after welding is higher when the outer plates 21R and 22R without the cutout CU are first welded, the subsequent handling of the structure is facilitated. Furthermore, since butt welding can be performed downward, weldability and strength are improved.

  In the welding process, the planar portions of the left outer plate 21 and the right outer plate 22 are welded together. For this reason, since distortion warping is reduced, the time for removing distortion is shortened, and a reduction in work efficiency is suppressed. Moreover, since distortion warping is suppressed, the deterioration of the quality of the crane post 2 can also be suppressed.

  When the outer plates 21R and 22R are welded, as shown in FIG. 15, the top base member 12 is attached to the top 2T side of the left outer plate 21 and the right outer plate 22 after the welding process is finished (step S107). Step S107 corresponds to a top base member attaching step. The top base member 12 is attached by welding, for example. In the present embodiment, the top base member 12 is attached to the top 2T side of the left outer plate 21 and the right outer plate 22 with the pulleys 13 and 14 attached, but the top base member 12 is left alone. The pulleys 13 and 14 may be attached to the top base member 12 after being attached to the top 2T side of the outer plate 21 and the right outer plate 22.

  The top base member 12 is attached in a state in which the left outer plate 21 and the right outer plate 22 are placed horizontally, that is, their longitudinal directions are installed along the horizontal direction. By doing in this way, since the one end part of the left side outer plate 21 and the right side outer plate 22 is fixed by the top base member 12, the intensity | strength of the structure comprised by these members improves, and a deformation | transformation is suppressed. . The top base member attaching process may be after the above-described welding process (it may be after the left outer plate 21 and the right outer plate 22 are temporarily fixed). That is, the top base member 12 may be attached to the top 2T side of the left outer plate 21 and the right outer plate 22 after main welding of the outer plates 21F and 22F where the notch CU exists.

  Next, the left outer plate 21 and the right outer plate 22 to which the outer plates 21R and 22R are finally welded are rotated (step S108). Step S108 corresponds to a rotation process. In the rotation step, the left outer plate 21 and the right outer plate 22 are rotated around an axis parallel to the longitudinal direction of the left outer plate 21 and the right outer plate 22 in a posture along the horizontal direction.

  In the rotation process, for example, the left outer plate 21 and the right outer plate 22 can be lifted and rotated by a crane or the like. However, it is preferable to use a rotating jig, which will be described later, because the work can be performed efficiently and safely. Even when the left outer plate 21 and the right outer plate 22 are lifted by a crane or the like, the axis parallel to the longitudinal direction of the left outer plate 21 and the right outer plate 22 is lifted and rotated in a posture along the horizontal direction. Work efficiency is improved.

  In the rotation process, for example, as shown in FIG. 16, the left outer plate 21 and the right outer plate 22 are reversed (rotated 180 degrees), so that the outer plates 21F and 22F having the cutout CU are moved to the surface plate 52 side. Deploy. And the remaining welding object part is welded by the welding torch 50 from the inner side surrounded by the left outer plate 21 and the right outer plate 22 (step S109). Step S109 corresponds to the second welding process. In the present embodiment, the outer plate 21F of the left outer plate 21 and the outer plate 22F of the right outer plate 22 are welded (main welding). In this case, a backing 51 is provided between the outer plates 21F and 22F and the surface plate 52 as in step S106. In step S109, various fittings are also attached to the left outer plate 21 and the right outer plate 22 by welding or the like. Note that attachment / welding of the fitting is appropriately performed after step S103. In this way, the crane post 2 shown in FIG. 2 is completed.

  As described above, the crane post manufacturing method according to the present embodiment can use a lot of automatic welding, so that work efficiency is improved. Moreover, since butt welding can be performed in a downward posture, weldability and strength can be improved. Furthermore, by welding at the flat surface, welding distortion can be minimized and a good quality crane post can be manufactured. Moreover, if the plate material is welded at each end portion (corner portion) to form a ridgeline of a crane post having a polygonal cross section, the number of welding increases. For example, in a crane post having an octagonal cross section, the plate members need to be welded eight times. Since the crane post manufacturing method according to the present embodiment press-bends the plate material to form the ridgeline of the crane post having a polygonal cross section and welds the flat surface portion, all the ridgelines need not be formed by welding. . For example, when a crane post having an octagonal cross section is manufactured by the method for manufacturing a crane post according to the present embodiment, welding of plate members is sufficient by performing butt welding of a flat surface portion four times. As described above, the crane post manufacturing method according to the present embodiment can greatly reduce the number of times of welding, thereby improving the productivity of the crane post. Thus, the crane post manufacturing method according to the present embodiment can efficiently manufacture a high-quality crane post at a low cost.

  When welding the outer plate 21F of the left outer plate 21 and the outer plate 22F of the right outer plate 22 in step S109, the planar portions of the outer plate 21F and the outer plate 22F are welded together. For this reason, since distortion warping is reduced, the time for removing distortion is shortened, and a reduction in work efficiency is suppressed. Moreover, since distortion warping is suppressed, the deterioration of the quality of the crane post 2 can also be suppressed. Furthermore, since butt welding can be performed downward, weldability and strength are improved.

  As described above, in the crane post manufacturing method according to the present embodiment, the plate splicing step in step S103 is not essential. Moreover, the order of the top base member attachment process of step S107 and the rotation process of step S108 does not matter.

  FIG. 17 is a perspective view showing a rotating jig that rotates the left outer plate and the right outer plate. In step S108, when rotating the left outer plate 21 and the right outer plate 22, it is preferable to use the rotating jig 60 shown in FIG. The rotating jig 60 arranges and supports the pair of annular structures 63 and 63 facing each other, and arranges the left outer plate 21 and the right outer plate 22 inside them. The pair of annular structures 63 and 63 are supported by the base 65 via a plurality of rollers 64, respectively. Since the roller 64 is rotated by the driving means, the rotation of the roller 64 is transmitted to the annular structure 63 and the annular structure 63 is rotated. Then, the left outer plate 21 and the right outer plate 22 supported by the pair of annular structures 63 and 63 also rotate around an axis parallel to the longitudinal direction.

  The annular structure 63 is a structure in which the first arc member 61 and the second arc member 62 are combined. The first arc member 61 and the second arc member 62 can be separated and fixed. When the left outer plate 21 and the right outer plate 22 are carried into the rotating jig 60, the second arc members 62 and 62 are removed from the pair of annular structures 63 and 63. Then, an opening is created in each of the first arc members 61, 61, and the left outer plate 21 and the right outer plate 22 are carried into the first arc members 61, 61 from the openings. Then, the second arc members 62 and 62 are attached to the first arc members 61 and 61, and the left outer plate 21 and the right outer plate 22 are supported by the pair of annular structures 63 and 63. If the left outer plate 21 and the right outer plate 22 are rotated using such a rotating jig 60, it is not necessary to lift them with a crane or the like when rotating them, so that work efficiency and safety are improved. Manufacturing cost can be reduced.

  FIG. 18 is a perspective view showing a crane post according to a modification of the present embodiment. 19 and 20 are diagrams illustrating a part of the manufacturing process of the crane post according to the modification of the present embodiment. In the present embodiment, as described above, the shape of the crane post is not limited to the octagonal frustum shape, and may be a quadrangular frustum shape, for example, like a crane post 2a shown in FIG. In this case, the crane post 2 a has four ridge lines B. The crane post 2a is manufactured with a left outer plate 21a and a right outer plate 22a.

  First, the crane post 2a bends a plate-shaped part cut out from a plate material to produce a left outer plate 21a and a right outer plate 22a as shown in FIG. A portion indicated by a symbol B in FIG. 19 is a ridge line. Both the left outer plate 21a and the right outer plate 22a are manufactured by press bending a single plate-like component. These are structures each having a ridgeline B at two locations and having a substantially U-shaped cross section. The ridge line B is formed by press bending in the bending process described above. This ridge line B becomes the ridge line B of the corner portion of the crane post 2a having a polygonal (quadrangle) cross section shown in FIG. A plurality of beams 15, 15 are stretched from the front side 2F toward the rear side 2R on the top side of the left outer plate 21a and the right outer plate 22a and joined by welding.

  The left outer plate 21 a and the right outer plate 22 a to which the beams 15, 15 are joined have a surface plate through a backing 51 with the opposite side to the side where the notch CU is formed facing downward in the vertical direction. 52 is installed. The portion of the groove HT opposite to the side where the notch CU is formed is butt welded (main welding) using the welding torch 50. Thereafter, the top base member 12 shown in FIG. 15 is attached to the top side of the left outer plate 21a and the right outer plate 22a. Then, by rotating the left outer plate 21a and the right outer plate 22a, the side on which the cutout CU of the left outer plate 21a and the right outer plate 22a is formed is installed on the surface plate 52 through the backing 51. Both are butt welded (main welding). By such a process, the crane post 2a shown in FIG. 18 is completed.

  As described above, the crane post manufacturing method and the crane post according to the present invention are useful for manufacturing a high-quality crane post.

DESCRIPTION OF SYMBOLS 1 Crane 2, 2a Crane post 2F Front side 2R Rear side 2T Top part 6 Jib 8 Cargo wire rope 11 Lifting wire rope 12 Top part base member 13, 14 Pulley 15 Beam 20 Outer cylinder 21, 21a Left side outer plate 21F, 21R, 22F , 22R outer plate 21a left outer plate 21Fp, 21Rp, 22Fp, 22Rp parts 22, 22a right outer plate 50 welding torch 51 backing 52 surface plate 60 rotating jig 61 first arc member 62 second arc member 63 annular structure 64 Roller 65 Base 100 Ship

Claims (2)

In manufacturing a crane post with a polygonal cross section having a plurality of ridges,
A material cutting step of cutting out a plurality of parts to be the outer plate of the crane post from a plate material;
A bending step of forming the ridge line on the component by bending the cut-out component;
The left outer plate and the right outer plate of the crane post obtained from the bent parts are opposed to each other and the longitudinal direction of the left outer plate and the right outer plate is aligned with the horizontal direction. And a component installation step of installing the crane post so that the rear side of the crane post is a lower side in the vertical direction;
A first welding step of welding a portion to be welded on the rear side of the crane post from an inner side surrounded by the left outer plate and the right outer plate;
A rotating step of rotating the left outer plate and the right outer plate after welding;
A second welding step of welding the remaining welding target part;
Including
Before the component installation step, welding the bent parts together to produce the left outer plate and the right outer plate,
A reinforcing member attaching step of attaching a reinforcing member to the top side of the left outer plate and the top side of the right outer plate before the plate joining step and before the component setting step;
The manufacturing method of the crane post characterized by including. In manufacturing a crane post with a polygonal cross section having a plurality of ridges,
A material cutting step of cutting out a plurality of parts to be the outer plate of the crane post from a plate material;
A bending step of forming the ridge line on the component by bending the cut-out component;
The left outer plate and the right outer plate of the crane post obtained from the bent parts are opposed to each other and the longitudinal direction of the left outer plate and the right outer plate is aligned with the horizontal direction. And a component installation step of installing the crane post so that the rear side of the crane post is a lower side in the vertical direction;
A first welding step of welding a portion to be welded on the rear side of the crane post from an inner side surrounded by the left outer plate and the right outer plate;
A top base member attaching step for attaching a top base member to the top side of the left outer plate and the right outer plate after welding;
A second welding step of welding the remaining welding target part;
Including
Before the component installation step, welding the bent parts together to produce the left outer plate and the right outer plate,
A reinforcing member attaching step of attaching a reinforcing member to the top side of the left outer plate and the top side of the right outer plate before the plate joining step and before the component setting step;
The manufacturing method of the crane post characterized by including.

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