Lifting jig and lifting method

Abstract

To provide a hanging tool that has a simple configuration and allows for proceeding hanging work for a plurality of suspended cargoes with different shapes and sizes.SOLUTION: A hanging tool 10 comprises: two longitudinal members 12, 14 that are stacked and connected together at the longitudinal center; lower members 20 that are provided below two regions between a connection position 16 of the longitudinal members 12, 14 and edge parts 12a, 12b, and that are formed, at intervals, with a plurality of hanging holes 24 to which suspended-cargo-side wires are coupled; and upper members 30 of the longitudinal members 12, 14 which are provided at an upper side of two positions separated at equal distance from the connection position 16 toward the edge sides, and to which a crane-side wire is coupled. Therein, the longitudinal members 12, 14 are connected such that an angle intersecting each other changes freely. Thereby, it is possible to handle the suspended cargoes with various shapes and sizes within a range that can be covered by the length of the longitudinal members 12, 14, and to allow for efficiently proceeding hanging work despite its simple structure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lifting jig used in lifting a load by a crane, and a lifting method for lifting a load by a crane using the lifting jig. [Background technology]

[0002] For example, when a relatively large load is lifted by a crane at a construction site, a lifting jig or a lifting balance is used to lift the load in a balanced manner. For example, Patent Document 1 discloses a lifting balance that is equipped with multiple hydraulic cylinders and uses the load of the load as the driving force for the hydraulic cylinders, thereby reducing costs and simplifying the control system for the cylinders. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-244143 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, loads to be lifted at construction sites come in a variety of shapes and sizes. For this reason, conventionally, a different lifting jig was prepared in advance for each different shape and size of load to lift the load in a balanced manner, and the lifting jig was changed and used depending on the load. This not only increased the cost of manufacturing multiple lifting jigs, but also reduced work efficiency due to the effort required to change the lifting jig during work. Furthermore, while the lifting balance disclosed in Patent Document 1 is useful for loads that require balancing adjustment using a hydraulic cylinder when lifting from the ground, for other loads, its performance was excessive and its structure was too complex.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to efficiently carry out the lifting work of multiple loads of different shapes and sizes using a lifting jig with a simple configuration. [Means for solving the problem]

[0006] (Aspects of the invention) The following embodiments of the present invention are examples of the configuration of the present invention, and are described in terms to facilitate understanding of the various configurations of the present invention. Each term does not limit the technical scope of the present invention, and while taking into consideration the best mode for carrying out the invention, some of the components of each term may be replaced or deleted, or other components may be added, and these may also be included in the technical scope of the present invention.

[0007] (1) A lifting jig used for lifting a load by a crane, comprising: two longitudinal members connected in a crossing manner, stacked one on top of the other, at the center of the longitudinal direction; a lower member provided on the lower side of each of the two longitudinal members in two regions between the connection position at the center of the longitudinal direction and both ends of the longitudinal direction, and having a plurality of lifting holes formed at intervals in the longitudinal direction to which load-side wires connected to the load are connected; and an upper member provided on the upper side of each of the two longitudinal members at two positions equidistant from the connection positions to both ends of the longitudinal direction, and to which crane-side wires connected to the crane are connected, wherein the two longitudinal members are connected so that the crossing angle between them can be freely changed.

[0008] The lifting jig described in this section includes two longitudinal members and a lower member and an upper member attached to each of the two longitudinal members. The two longitudinal members are stacked one above the other at their longitudinal centers and connected in a crossing manner at these locations. The lower members are provided below two regions between the connection position at the longitudinal center of each longitudinal member and both longitudinal ends of each longitudinal member. That is, the lower members are provided in each longitudinal member in a region between the connection position and one longitudinal end and a region between the connection position and the other longitudinal end, resulting in four regions in the lifting jig as a whole. Each of these lower members has multiple lifting holes formed at intervals along the longitudinal direction of the longitudinal member. A load-side wire connected to the load is connected to one of these multiple lifting holes during lifting operations. Therefore, the lifting jig and the load are connected by four load-side wires.

[0009] The upper members are provided above two positions equidistant from the connection positions of each longitudinal member toward both ends of each longitudinal member in the longitudinal direction. That is, for each longitudinal member, the upper members are provided at a position a fixed distance from the connection positions on one side of the longitudinal direction and a similar fixed distance from the connection positions on the other side of the longitudinal direction, resulting in four positions on the lifting jig as a whole. A crane wire connected to a crane during lifting operations is connected to each of these upper members. Therefore, the lifting jig and the crane are connected by four crane wires. Furthermore, the two longitudinal members connected in an intersecting manner as described above are connected so that the intersecting angle between them can be freely changed.

[0010] With this configuration, the connection position of the load-side wire can be freely selected from multiple lifting holes in each lower member, and the crossing angle between the two longitudinal members can be changed depending on the load. Therefore, for example, to ensure that the load is lifted in a balanced manner, the four lifting positions for connecting the load-side wires and the crossing angle between the two longitudinal members are preset for each load of different shapes and sizes through structural calculations of the load. During the load lifting operation, the load-side wires are connected to the lifting holes at positions corresponding to the predetermined lifting positions in each lower member, and the crane-side wires are connected to the four upper members. The load is then lifted by the crane. The crossing angle between the two longitudinal members then changes to the predetermined angle for each load and stops at that angle.

[0011] This allows the load to be lifted in a balanced manner at an appropriate lifting position and crossing angle of the longitudinal members according to the shape and size of the load. Furthermore, the lifting holes to be used can be freely selected and the crossing angle of the two longitudinal members can be freely changed, so loads of various shapes and sizes can be accommodated within the range covered by the length of the two longitudinal members. This eliminates the need to change the lifting jig for each load of different shapes and sizes, allowing for efficient lifting operations. Moreover, efficient lifting operations are achieved despite the simple configuration of two longitudinal members, an upper member, and a lower member, without the use of complex mechanisms such as hydraulic cylinders.

[0012] (2) In the above paragraph (1), the lower member is formed of a plate material that extends in the longitudinal direction and protrudes downward, and of the two longitudinal members, the lower member provided in the two regions of the upper longitudinal member and the lower member provided in the two regions of the lower longitudinal member have their lower edges at the same height in the vertical direction in which the two longitudinal members are stacked, and both of the multiple hanging holes are formed at the same height. In the hanging jig described in this section, the lower members provided in two regions of each longitudinal member are formed of a plate material that extends in the longitudinal direction of the longitudinal member and protrudes downward, so that two surfaces of the plate material face in directions perpendicular to both the longitudinal direction and the up-down direction of the longitudinal member, and multiple hanging holes are formed through the two surfaces.

[0013] Furthermore, the lower edges of the lower members provided in two regions of one of the two longitudinal members stacked on top of the other longitudinal member stacked on top of the other longitudinal member are located at the same height in the vertical direction in which the two longitudinal members are stacked. That is, the plate material serving as the lower member provided on the lower longitudinal member protrudes downward by a length necessary for drilling multiple lifting holes and connecting the load-side wires to the lifting holes, and the plate material serving as the lower member provided on the upper longitudinal member protrudes downward beyond the lower longitudinal member to the same position as the lower edge of the plate material of the lower longitudinal member.

[0014] As a result, the lower edges of the four plates extending downward from the two intersecting longitudinal members are positioned on the same plane in an X-like positional relationship in a plan view, allowing the lifting jig to maintain a stable position on the ground or other surface when not in use. Furthermore, the multiple lifting holes formed in each of the lower members are formed at the same height in the lower member provided on the upper longitudinal member and the lower member provided on the lower longitudinal member. As a result, by making the lengths of the four load-side wires connected to the load the same, the load will not be lifted at an angle due to the connection between the lifting jig and the load, and the load will be lifted in a more stable position.

[0015] (3) In the above paragraphs (1) and (2), the upper member provided at the two positions of the upper longitudinal member and the upper member provided at the two positions of the lower longitudinal member are lifting jigs in which the connection positions of both with the crane side wire are at the same height in the vertical direction in which the two longitudinal members are stacked. The hanging jig described in this section specifies upper members provided at two positions on one of two longitudinal members that is stacked on top of the other, and upper members provided at two positions on the other longitudinal member that is stacked on the bottom of the other.

[0016] Specifically, the connection positions of the upper member of the upper longitudinal member and the upper member of the lower longitudinal member to the crane wire are at the same height in the vertical direction in which the two longitudinal members are stacked. That is, the upper member attached to the lower longitudinal member protrudes upward at least beyond the upper longitudinal member to the same height as the position where the crane wire is connected to the upper member of the upper longitudinal member, and the crane wire is connected at the same height as the upper member of the upper longitudinal member. In this way, by making the lengths of the four crane wires connected to the crane the same, the load will not be lifted at an angle due to the connection between the lifting jig and the crane, and the load will be lifted in a more stable position.

[0017] (4) In the above items (1) to (3), each of the two longitudinal members is formed from a square steel pipe, the lower member is attached to the lower surface of the steel pipe, and the upper member is attached to the upper surface of the steel pipe. The lifting jig described in this section has two longitudinal members each formed from a square steel pipe, with a lower member attached to two areas on the underside of each steel pipe and an upper member attached to two positions on the top of each steel pipe. This configuration makes it easy to manufacture the lifting jig, and by using steel pipes, it is possible to ensure both the necessary strength and weight reduction.

[0018] (5) In the above items (1) to (4), a lifting jig is provided with lifting rings at at least four locations on the load, taking into consideration the center of gravity, and the load-side wire connected to the lifting rings is connected to the lifting hole. The lifting jig described in this section has four lifting rings provided at the load, which are the destination of the load-side wires that are connected to the lifting holes in the lower member. That is, for each load of different shape and size, four lifting positions are determined that will allow each load to be lifted in a balanced manner through structural calculations that take into account at least the center of gravity of the load, and lifting rings are provided at those positions. Then, the load-side wires are connected to these four lifting rings, and each of them is connected to a lifting hole, among multiple lifting holes formed in each lower member of the lifting jig, that is located at a position that corresponds to the position of the lifting ring.

[0019] Here, regarding the method for selecting the lifting holes corresponding to the positions of the lifting rings (lifting positions), first, imagine a state in which, in a plan view, the connection positions of the two longitudinal members are aligned with the center of gravity of the load when the lifting jig is virtually placed on top of the load, and each of the two longitudinal members passes through two lifting positions of the load. Then, from among the multiple lifting holes formed in each lower member, a lifting hole is selected so that its distance from the connection position of the longitudinal member is as equal as possible to the distance from the center of gravity of the load to each lifting position. When the load-side wire is connected to each of the selected lifting holes and the load is lifted by a crane, the connection positions of the two longitudinal members are located directly above the center of gravity of the load, and the positions and intersection angles of the two longitudinal members are such that they overlap the four lifting positions of the load in a plan view. This allows the load to be lifted in a more balanced manner.

[0020] (6) In the above items (1) to (5), a lifting jig for lifting a deck slab as the load. The lifting jig described in this section is used to lift deck slabs used in the construction of bridges and other structures. Deck slabs are manufactured in various shapes and sizes depending on the shape of the bridge or other structure and the installation location, and are mainly lifted by a crane during installation. Therefore, multiple deck slabs of different shapes and sizes can be lifted using the lifting jig described in this section without having to be replaced for each deck slab as with conventional lifting jigs, significantly improving the efficiency of deck installation work.

[0021] (7) A method for lifting a load with a crane using a lifting jig, comprising: two longitudinal members connected in a manner that they are stacked one on top of the other and cross each other at the center of the longitudinal direction; a lower member provided on the lower side of each of the two longitudinal members in two regions between the connection position at the center of the longitudinal direction and both ends of the longitudinal direction, and having a plurality of lifting holes formed at intervals in the longitudinal direction to which load-side wires connected to the load are connected; and a lower member provided on the upper side of each of the two longitudinal members at two positions equidistant from the connection position to both ends of the longitudinal direction, and having a plurality of lifting holes formed at intervals in the longitudinal direction to which load-side wires connected to the load are connected, and and an upper member to which a crane side wire is connected, wherein the load side wire is connected to one of the plurality of lifting holes in each of the lower members provided in the two regions of each of the two longitudinal members, and the crane side wire is connected to each of the upper members provided in the two positions of each of the two longitudinal members, and while the load is being lifted by the crane via the lifting jig, the crossing angle of the two longitudinal members can be freely changed so that it is set to an angle set for each of the loads.

[0022] (8) In the above item (7), the lower member is formed of a plate material that extends in the longitudinal direction and protrudes downward, and of the two longitudinal members, the lower member provided in the two regions of the upper longitudinal member and the lower member provided in the two regions of the lower longitudinal member are arranged so that the lower edges of both are at the same height in the vertical direction in which the two longitudinal members are stacked, and the multiple lifting holes of both are formed at the same height. (9) In the above paragraphs (7) and (8), a lifting method is provided in which the connection positions of the upper member provided at the two positions of the upper longitudinal member and the upper member provided at the two positions of the lower longitudinal member are at the same height with respect to the vertical direction in which the two longitudinal members are stacked. (10) In the above items (7) to (9), a lifting method is provided in which each of the two longitudinal members is formed from a square steel pipe, the lower member is attached to the lower surface of the steel pipe, and the upper member is attached to the upper surface of the steel pipe.

[0023] (11) In the above items (7) to (10), a lifting method is provided in which lifting rings are provided at at least four locations on the load, taking into consideration the center of gravity, and the load-side wires connected to the lifting rings are connected to the lifting holes. (12) In the above items (7) to (11), a lifting method in which a deck slab is lifted as the load. The lifting methods described in items (7) to (12) are each performed using the lifting jigs described in items (1) to (6) above, and thus have the same effect as the lifting jigs described in items (1) to (6) above. [Effects of the Invention]

[0024] Because the present invention has the above-described configuration, it is possible to efficiently carry out the lifting work of multiple loads of different shapes and sizes using a lifting jig with a simple configuration. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a perspective view showing an example of a configuration of a hanging jig according to an embodiment of the present invention. [Figure 2] 2A and 2B show details of the upper longitudinal member of the hanging jig in FIG. 1 when the two longitudinal members are perpendicular to each other, where (a) is a front view, (b) is an enlarged cross-sectional view taken along line AA in (a), and (c) is an enlarged plan view of the vicinity of line AA in (a). [Figure 3] 2A and 2B show details of mainly the lower longitudinal member of the hanging jig in FIG. 1 when the two longitudinal members are perpendicular to each other, where (a) is a front view, (b) is an enlarged cross-sectional view taken along line BB in (a), and (c) is an enlarged plan view of the vicinity of line BB in (a). [Figure 4]1A and 1B are three-view diagrams of a deck slab as a load to be lifted using a lifting jig according to an embodiment of the present invention, where (a) is a plan view, (b) is a partially transparent front view, and (c) is a partially transparent side view. [Figure 5] 5A and 5B are three-view diagrams of a deck slab having a different shape from that shown in FIG. 4, as a load to be lifted using a lifting jig according to an embodiment of the present invention, where (a) is a plan view, (b) is a partially see-through front view, and (c) is a partially see-through side view. [Figure 6] These are planar images showing a method for determining the suspension position of the deck, where (a) corresponds to the deck in Figure 4 and (b) corresponds to the deck in Figure 5. [Figure 7] 1 is a conceptual diagram illustrating a state in which a load is lifted by a crane using a lifting jig according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Here, detailed descriptions of parts that are the same as or corresponding to those in the prior art will be omitted, and the same reference numerals will be used throughout the drawings to indicate the same or corresponding parts. First, as shown in Figure 7, the lifting jig 10 according to an embodiment of the present invention is positioned between the crane side wire 42 connected to the crane 60 and the load side wire 40 connected to the load 50 when lifting the load 50 by the crane 60, thereby lifting the load 50 in a balanced manner.

[0027] As shown in Fig. 1, a lifting jig 10 according to an embodiment of the present invention includes two longitudinal members 12 and 14, a lower member 20 provided on each of the two longitudinal members 12 and 14, and an upper member 30 also provided on each of the two longitudinal members 12 and 14. The two longitudinal members 12 and 14 are connected so that they are stacked one on top of the other and cross each other, with the longitudinal member 12 on the upper side and the longitudinal member 14 on the lower side, and the connection position 16 is located at the center of the longitudinal direction of the two longitudinal members 12 and 14. Note that Fig. 2 mainly shows details of the longitudinal member 12 and the lower member 20 and upper member 30 provided thereon, and Fig. 3 mainly shows details of the longitudinal member 14 and the lower member 20 and upper member 30 provided thereon, so please refer to these figures hereinafter.

[0028] The two longitudinal members 12 and 14 connected as described above are connected so that the mutual intersection angle K (see FIG. 6 ) in a plan view can be freely changed. That is, for example, as shown in FIG. 7 , when the lifting jig 10 is lifted together with the load 50 by a crane 60, the two longitudinal members 12 and 14 rotate relatively about the connection position 16, and then the two longitudinal members 12 and 14 are connected so that the rotation stops at a certain angle where the intersection angle K is set according to the connection position of the load-side wire 40, etc. This connection is achieved at the connection position 16 using, for example, a bolt. In this embodiment, each of the two longitudinal members 12 and 14 is formed from a square steel pipe. The distance between both ends 12a, 12b of the longitudinal member 12 and the distance between both ends 14a, 14b of the longitudinal member 14 are equal to each other, and although not limited thereto, the distance is, for example, about 4200 mm. The lengths of the two longitudinal members 12 and 14 may be set according to the size of the load 50 to be suspended.

[0029] The lower members 20 (20A, 20B) of the longitudinal member 12 are provided below two regions between the connection position 16, which is located in the longitudinal center of the longitudinal member 12, and both end portions 12a and 12b. As can be seen in FIGS. 1 and 2, in this embodiment, rectangular plate-like lower members 20A and 20B made of steel or the like are attached to the lower surface of the longitudinal member 12, which is a square steel pipe. As shown in FIG. 2(a), the lower member 20A extends from one end portion 12a of the longitudinal member 12 to a position on the left side of the connection position 16 in the drawing, with its lower edge 22 positioned below the longitudinal member 14. In addition, the lower member 20B extends in the longitudinal direction of the longitudinal member 12 from the other end 12b of the longitudinal member 12 to a position to the right of the connection position 16 in the figure, and its lower edge 22 is at the same height as the lower edge 22 of the lower member 20A, below the longitudinal member 14.

[0030] Each of the lower members 20A, 20B is provided with a plurality of reinforcing members 26 near the connection portion to the longitudinal member 12. Furthermore, each of the lower members 20A, 20B is formed with a plurality of suspension holes 24 for connecting the load-side wires 40 (see FIG. 7). These suspension holes 24 are formed near the lower ends of the lower members 20A and 20B at positions equidistant from one another along the longitudinal direction of the longitudinal member 12. Although not limited thereto, the size of the lower members 20A, 20B is approximately 1600 mm in the left-right direction and 380 mm in the up-down direction in FIG. 2(a), and the distance between the centers of adjacent suspension holes 24 is approximately 100 mm.

[0031] In contrast, the lower members 20 (20C, 20D) of the longitudinal member 14, like the lower member 20 of the longitudinal member 12, are provided below two regions between the connection position 16, located in the longitudinal center of the longitudinal member 14, and both end portions 14a and 14b. As can be seen in FIGS. 1 and 3, in this embodiment, rectangular plate-like lower members 20C and 20D made of steel or the like are attached to the underside of the longitudinal member 14, which is a rectangular steel pipe. As shown in FIG. 3(a), the lower member 20C extends from one end 14a of the longitudinal member 14 to a position to the left of the connection position 16 in the figure, in the longitudinal direction of the longitudinal member 14. The lower member 20D extends from the other end 14b of the longitudinal member 14 to a position to the right of the connection position 16 in the figure, in the longitudinal direction of the longitudinal member 14. The lower edges 22 of the lower members 20C and 20D are at the same height.

[0032] Like the lower members 20A and 20B, each of the lower members 20C and 20D is provided with a plurality of reinforcing members 26 near the connection portion to the longitudinal member 14, and a plurality of lifting holes 24 for connecting the load-side wires 40 (see FIG. 7) are formed at equally spaced positions along the longitudinal direction of the longitudinal member 14. Although not limited thereto, the size of the lower members 20C and 20D is approximately 1600 mm in the left-right direction in FIG. 3(a) and 100 mm in the up-down direction, similar to the lower members 20A and 20B, and the distance between the centers of adjacent lifting holes 24 is approximately 100 mm, similar to the lower members 20A and 20B.

[0033] 1, the lower edges 22 of the lower members 20A and 20B provided on the upper longitudinal member 12 and the lower edges 22 of the lower members 20C and 20D provided on the lower longitudinal member 14 are at the same height and positioned on the same plane. Furthermore, the distance from the lower edges 22 of the lower members 20A and 20B to the plurality of hanging holes 24 formed on the lower members 20A and 20B is equal to the distance from the lower edges 22 of the lower members 20C and 20D to the plurality of hanging holes 24 formed on the lower members 20C and 20D. In other words, the plurality of hanging holes 24 formed on the four lower members 20A to 20D are all positioned at the same height.

[0034] 1 and 2, the upper members 30 (30A, 30B) of the longitudinal member 12 are provided above two positions between the connection position 16 located in the longitudinal center of the longitudinal member 12 and both end portions 12a and 12b. In the longitudinal direction of the longitudinal member 12, the distance from the connection position 16 to the upper member 30A is equal to the distance from the connection position 16 to the upper member 30B. In this embodiment, the upper members 30A and 30B, which are made of steel or the like, are attached to the upper surface of the longitudinal member 12, which is a rectangular steel pipe, in a manner that they protrude upward.

[0035] The upper members 30A and 30B protrude to the same height position, and holes are formed at the tips of each of them as connection positions 32 to which crane wires 42 (see FIG. 7) are connected. In FIG. 1, connectors 46 that connect the upper members 30A and 30B to the crane wires 42 are attached to the connection positions 32 of the upper members 30A and 30B. Two reinforcing members 36 are provided on each of the upper members 30A and 30B near the connection portions to the longitudinal member 12. Although not limited thereto, the size of the upper members 30A and 30B is such that the height from the top surface of the longitudinal member 12 is approximately 125 mm, and the distance in the left-right direction from the connection positions 16 to the upper members 30A and 30B in FIG. 2(a) is approximately 1600 mm.

[0036] 1 and 3, the upper members 30 (30C, 30D) of the longitudinal member 14, like the upper member 30 of the longitudinal member 12, are provided above two positions between the connection position 16 located in the longitudinal center of the longitudinal member 14 and both end portions 14a and 14b. In addition, with respect to the longitudinal direction of the longitudinal member 14, the distance from the connection position 16 to the upper member 30C is equal to the distance from the connection position 16 to the upper member 30D. In this embodiment, the upper members 30C and 30D, which are made of steel or the like, are attached to the upper surface of the longitudinal member 14, which is a rectangular steel pipe, in a manner that they protrude upward.

[0037] The upper members 30C and 30D protrude to the same height, and holes are formed at the tips of the upper members 30C and 30D as connection positions 32 to which crane wires 42 (see FIG. 7) are connected. Note that, as with the upper members 30A and 30B, in FIG. 1, connectors 46 are attached to the connection positions 32 of the upper members 30C and 30D, connecting the upper members 30C and 30D to the crane wires 42. Each of the upper members 30C and 30D has two reinforcing members 36 near the connection portion to the longitudinal member 14. Although not limited thereto, the size of the upper members 30C and 30D is approximately 410 mm in height from the top surface of the longitudinal member 14, and the distance from the connection position 16 to the upper members 30C and 30D in the left-right direction in FIG. 3(a) is approximately 1600 mm. In other words, the distance from the connection position 16 to each of the four upper members 30A to 30D is the same. Moreover, all four upper members 30A to 30D protrude to the same height position, and all connecting positions 32 are at the same height position.

[0038] 4 and 5 show two deck slabs 56 of different shapes and sizes as examples of a load 50 to be lifted using the lifting jig 10 according to an embodiment of the present invention. Each deck slab 56 is provided with lifting rings 52 at positions corresponding to four lifting positions that will be set as described below. The lifting rings 52 are formed, for example, from shaped round steel bars, and are embedded between the upper and lower reinforcing bars of the deck slab 56 when pouring concrete during the fabrication of the deck slab 56. Then, as shown in FIG. 7, when the deck slab 56 is lifted by a crane 60, the load-side wires 40 are connected to each of the lifting rings 52 via connectors or the like.

[0039] Next, a method for setting the suspension position of the deck slab 56 will be briefly described with reference to FIG. 6. FIG. 6(a) is an image diagram corresponding to the deck slab 56 in FIG. 4, and FIG. 6(b) is an image diagram corresponding to the deck slab 56 in FIG. 5. As shown, two imaginary lines (indicated by reference numerals 12' and 14') indicating the arrangement of the two longitudinal members 12, 14 and an imaginary circle C are superimposed on a plan view of the deck slab 56 (indicated by reference numeral 56') in which the center of gravity G is shown. The intersection position (corresponding to the connection position 16) of the two imaginary lines 12' and 14' is aligned with the center of gravity G of the deck slab 56', and the intersection angle between them is indicated by reference numeral K. The imaginary circle C indicates positions where four upper members 30 (indicated by reference numeral 30' in FIG. 6) that are equidistant from the connection position 16 can be arranged, and the radius of the imaginary circle C corresponds to the distance from the connection position 16 to each upper member 30.

[0040] In the above-described state, the intersection angle K of the two imaginary lines 12' and 14' is set so that the four upper members 30' are positioned on or near the deck slab 56' with as much space between them as possible. Then, four suspension positions S are set on the two imaginary lines 12' and 14' at positions away from the four upper members 30' toward the center of gravity G. The distances L from the four upper members 30' to the four suspension positions S are set based on structural calculations of the deck slab 56 to ensure a minimum clearance from the edge of the deck slab 56' so as not to damage the deck slab 56, and so that the load is evenly distributed to the four suspension positions S, and may be different sizes. Note that auxiliary lines for structural calculations are drawn on the deck slab 56'.

[0041] Then, lifting rings 52 as shown in Figures 4 and 5 are installed at the four lifting positions S set as described above, and the load-side wires 40 are connected to them. Furthermore, each of the four load-side wires 40 is connected to a destination lifting hole 24 selected from the plurality of lifting holes 24 provided in each of the four lower members 20. At this time, the destination lifting hole 24 is selected as the lifting hole 24 that is closest to the upper member 30 or the connection position 16, with respect to the distance L from the upper member 30' to the lifting position S as shown in Figure 6 and the distance from the center of gravity G to the lifting position S. For example, consider the case where the upper left upper member 30' in Figure 6(a) corresponds to the upper member 30A of the longitudinal member 12 shown in Figure 2(a). In this case, from among the multiple hanging holes 24 formed in the lower member 20A, a hanging hole 24 is selected whose left-right distance in Figure 2(a) from the upper member 30A or the connection position 16 is as close as possible to the distance L in the upper left corner in Figure 6(a) or the distance from the center of gravity G to the hanging position S.

[0042] The lifting jig 10 according to the embodiment of the present invention is not limited to the configuration shown in FIGS. 1 to 3 and may have other configurations. For example, the two longitudinal members 12, 14 may be formed of pipe material other than square steel pipes, or may be formed of a material other than a pipe material. Furthermore, the lower member 20 and the upper member 30 may have shapes different from those shown in the drawings, and the number and spacing of the lifting holes 24 formed in each of the lower member 20 may also be different from those shown in the drawings. Furthermore, the lifting jig 10 according to the embodiment of the present invention is not intended to be used only for the deck slab 56 shown in FIGS. 4 and 5 , but may also be used to lift loads 50 other than the deck slab 56. Furthermore, the lifting rings 52 provided on the load 50 do not necessarily need to be provided one-to-one with respect to the four lifting positions S. A total of eight lifting rings 52 may be provided, such that one lifting position S is covered by two lifting rings 52. Furthermore, depending on the size and shape of the suspended load 50, the suspension positions S may be set at only two locations.

[0043] According to the embodiment of the present invention configured as described above, the following operational effects can be obtained. Specifically, as shown in FIGS. 1 to 3, the lifting jig 10 according to the embodiment of the present invention includes two longitudinal members 12, 14, and a lower member 20 and an upper member 30 provided on each of the two longitudinal members 12, 14. The two longitudinal members 12, 14 are stacked one above the other at their longitudinal centers and connected in a manner that crosses each other at these points. The lower member 20 is provided below two regions between the connection position 16 at the longitudinal center of each of the longitudinal members 12, 14 and both longitudinal end portions 12a, 12b, 14a, and 14b of each of the longitudinal members 12, 14.

[0044] That is, the lower members 20 are provided in each of the longitudinal members 12, 14 in the region between the connection position 16 and one longitudinal end portion 12a, 14a, and in the region between the connection position 16 and the other longitudinal end portion 12b, 14b, for a total of four regions in the hoisting jig 10. Each of these lower members 20 (20A to 20D) has a plurality of hoisting holes 24 formed at intervals in the longitudinal direction of the longitudinal members 12, 14, and a load-side wire 40 (see FIG. 7) connected to the load 50 is connected to one of these plurality of hoisting holes 24 during hoisting work. Therefore, the hoisting jig 10 and the load 50 are connected by four load-side wires 40.

[0045] The upper members 30 are provided above two positions equidistant from the connection positions 16 of the longitudinal members 12, 14 toward both longitudinal ends 12a, 12b, 14a, 14b of each longitudinal member 12, 14. That is, the upper members 30 are provided on each of the longitudinal members 12, 14 at a position a certain distance away from the connection positions 16 toward one longitudinal side (12a, 14a side) and a similar certain distance away from the connection positions 16 toward the other longitudinal side (12b, 14b side), for a total of four positions on the lifting jig 10. Then, crane-side wires 42 (see FIG. 7) connected to the crane 60 are connected to each of these upper members 30 (30A-30D) during lifting operations. Therefore, the lifting jig 10 and the crane 60 are connected by four crane-side wires 42. Furthermore, the two longitudinal members 12, 14 connected in an intersecting manner as described above are connected so that the intersecting angle K (see FIG. 6) between them can be freely changed.

[0046] With this configuration, the connection position of the load-side wire 40 can be freely selected from among the multiple lifting holes 24 in each lower member 20, and the crossing angle K of the two longitudinal members 12, 14 can be changed depending on the load 50. Therefore, for example, to ensure that the load 50 is lifted in a balanced manner, as shown in FIG. 6 , four lifting positions S of the load 50 to which the load-side wire 40 is connected and the crossing angle K of the two longitudinal members 12, 14 are preset for each load 50 of different shapes and sizes through structural calculations of the load 50. Then, during the lifting operation of the load 50, the load-side wire 40 is connected to the lifting hole 24 at a position corresponding to the predetermined lifting position S in each lower member 20, and the crane-side wire 42 is connected to the upper members 30 provided at the four positions, and the load 50 is then lifted by the crane 60. Then, the crossing angle K of the two longitudinal members 12, 14 changes to a predetermined angle for each suspended load 50, and stops at that angle.

[0047] This allows the load 50 to be lifted in a balanced manner at an appropriate lifting position S and intersection angle K between the longitudinal members 12, 14 according to the shape and size of the load 50. Furthermore, the lifting holes 24 to be used can be freely selected, and the intersection angle K between the two longitudinal members 12, 14 can be freely changed, making it possible to accommodate loads 50 of various shapes and sizes within the range that can be covered by the lengths of the two longitudinal members 12, 14. This eliminates the need to change the lifting jig 10 for each load 50 of different shapes and sizes, making it possible to proceed with lifting operations efficiently. Moreover, efficient lifting operations can be achieved despite the simple configuration of the two longitudinal members 12, 14, the lower member 20, and the upper member 30, without using complex mechanisms such as hydraulic cylinders.

[0048] 1 to 3, in the hanging jig 10 according to the embodiment of the present invention, the lower members 20 provided in two regions of each of the longitudinal members 12, 14 are formed of a plate material, and these plate members extend in the longitudinal direction of the longitudinal members 12, 14 and protrude downward. Therefore, two surfaces of the plate material face in directions perpendicular to both the longitudinal direction and the up-down direction of the longitudinal members 12, 14, and a plurality of hanging holes 24 are formed through the two surfaces. Furthermore, of the two longitudinal members 12, 14, the lower members 20A, 20B provided in two regions of one longitudinal member 12 stacked on top of the other longitudinal member 14 and the lower members 20C, 20D provided in two regions of the other longitudinal member 14 stacked on the bottom have their lower edges 22 positioned at the same height in the up-down direction when the two longitudinal members 12, 14 are stacked. That is, the plate materials serving as the lower members 20C and 20D provided on the lower longitudinal member 14 protrude downward by a length necessary for drilling the multiple lifting holes 24 and connecting the load-side wires 40 to the lifting holes 24. In addition, the plate materials serving as the lower members 20A and 20B provided on the upper longitudinal member 12 protrude downward beyond the lower longitudinal member 14 to the same position as the lower edge 22 of the plate material of the lower longitudinal member 14.

[0049] As a result, the lower edges 22 of a total of four plates extending downward from the two intersecting longitudinal members 12, 14 are positioned on the same plane in an X-like positional relationship in a plan view, so that the lifting jig 10 can be maintained in a stable position on the ground or the like when not in use, as shown in Figure 1. Furthermore, the multiple lifting holes 24 formed in each of the lower members 20 are formed at the same height in the lower members 20A, 20B provided on the upper longitudinal member 12 and the lower members 20C, 20D provided on the lower longitudinal member 14. As a result, by making the lengths of the four load-side wires 40 connected to the load 50 the same, the load 50 will not be lifted at an angle due to the connection between the lifting jig 10 and the load 50, and the load 50 can be lifted in a more stable position.

[0050] Furthermore, in the lifting jig 10 according to the embodiment of the present invention, the upper members 30A, 30B provided at two positions on one longitudinal member 12 stacked on top of the other longitudinal member 14 of the two longitudinal members 12, 14 are specified as follows: Specifically, the upper members 30A, 30B of the upper longitudinal member 12 and the upper members 30C, 30D of the lower longitudinal member 14 have their connection positions 32 with the crane-side wire 42 at the same height in the vertical direction in which the two longitudinal members 12, 14 are stacked.

[0051] That is, the upper members 30C, 30D provided on the lower longitudinal member 14 protrude upward at least beyond the upper longitudinal member 12 to the same height as the position 32 where the crane wires 42 are connected to the upper members 30A, 30B of the upper longitudinal member 12, and the crane wires 42 are connected at the same height as the upper members 30A, 30B of the upper longitudinal member 12. In this way, by making the lengths of the four crane wires 42 connected to the crane 60 the same, the load 50 will not be lifted at an angle due to the connection between the lifting jig 10 and the crane 60, and the load 50 can be lifted in a more stable posture.

[0052] Furthermore, in the lifting jig 10 according to the embodiment of the present invention, each of the two longitudinal members 12, 14 is formed from a square steel pipe, and lower members 20A, 20B or 20C, 20D are attached to two areas on the underside of each steel pipe, and upper members 30A, 30B or 30C, 30D are attached to two positions on the top surface of each steel pipe. This configuration makes it easy to manufacture the lifting jig 10, and by using steel pipes, it is possible to ensure both the necessary strength and weight reduction.

[0053] 4 and 5, the lifting jig 10 according to the embodiment of the present invention has four lifting rings 52 at four lifting positions S on the load 50 to which the load-side wires 40 connected to the lifting holes 24 of the lower member 20 are connected. That is, for each load 50 of different shapes and sizes, four lifting positions S at which each load 50 can be lifted in a balanced manner are determined by structural calculations that take into account at least the center of gravity G of the load 50 as shown in FIG. 6, and at least four lifting rings 52 are provided to correspond to these positions. The load-side wires 40 are then connected to these four lifting rings 52, and each of these is connected to a lifting hole 24, among the multiple lifting holes 24 formed in each lower member 20 of the lifting jig 10, that is located at a position corresponding to the position of the lifting ring 52.

[0054] Here, regarding a method for selecting the hanging holes 24 corresponding to the positions of the hanging rings 52 (hanging positions S), first, assume that, in a plan view when the hanging jig 10 is virtually superimposed on the suspended load 50, the connection positions 16 of the two longitudinal members 12, 14 are aligned with the center of gravity G of the suspended load 50, and each of the two longitudinal members 12, 14 passes through two hanging positions S of the suspended load 50 (see FIG. 6). Then, in this state, of the multiple hanging holes 24 formed in each lower member 20, a hanging hole 24 is selected such that the distance from the connection positions 16 of the longitudinal members 12, 14 is as equal as possible to the distance from the center of gravity G of the suspended load 50 to each hanging position S. When the load-side wires 40 are connected to the selected lifting holes 24 and the load 50 is lifted by the crane 60, the connection position 16 of the two longitudinal members 12, 14 is located directly above the center of gravity G of the load 50, and the two longitudinal members 12, 14 are positioned and at an intersection angle K such that they overlap the four lifting positions S of the load 50 in a plan view. This makes it possible to lift the load 50 in an even more balanced manner.

[0055] In addition, the lifting jig 10 according to the embodiment of the present invention is used to lift a deck 56 used in the construction of a bridge or the like as a load 50, as shown in Figures 4 and 5. Deck slabs 56 are manufactured in various shapes and sizes depending on the shape of the bridge or the like and the installation location, and are mainly lifted by a crane 60 during installation. Therefore, multiple deck slabs 56 of different shapes and sizes can be lifted using the lifting jig 10 according to the embodiment of the present invention without having to be replaced for each deck slab 56 as with conventional lifting jigs, and the efficiency of the installation work of the deck slabs 56 can be significantly improved. In addition, the lifting method according to the embodiment of the present invention can achieve the same effects as the lifting jig 10 by being carried out using the lifting jig 10 according to the embodiment of the present invention described above. [Explanation of symbols]

[0056] 10: Lifting jig, 12, 14: Longitudinal member, 12a, 12b, 14a, 14b: End portion, 16: Connection position, 20 (20A to 20D): Lower member, 22: Lower edge, 24: Lifting hole, 30 (30A to 30D): Upper member, 32: Connection position, 40: Load side wire, 42: Crane side wire, 50: Lifted load, G: Center of gravity, 52: Lifting ring, 56: Deck slab, 60: Crane, K: Intersection angle

Claims

1. A lifting jig used for lifting loads by a crane, Two longitudinal members that are connected in a crossing manner and stacked one on top of the other at the center in the longitudinal direction; a lower member provided on each of the two longitudinal members in two regions between the connection position in the center of the longitudinal direction and both ends of the longitudinal direction, the lower member having a plurality of hoisting holes formed at intervals in the longitudinal direction to which load-side wires connected to the hoisting load are connected; an upper member provided on each of the two longitudinal members at two positions equidistant from the connection position toward both ends in the longitudinal direction, and to which a crane side wire connected to the crane is connected; The two longitudinal members are connected so that the crossing angle between them can be freely changed, the lower member is formed of a plate member extending in the longitudinal direction and protruding downward, Of the two longitudinal members, the lower member provided in the two regions of the upper longitudinal member and the lower member provided in the two regions of the lower longitudinal member have lower edges at the same height in the vertical direction in which the two longitudinal members are stacked, and the multiple hanging holes of both are formed at the same height, Of the two longitudinal members, the upper member provided at the two positions of the upper longitudinal member and the upper member provided at the two positions of the lower longitudinal member are connected to the crane-side wire at the same height in the vertical direction in which the two longitudinal members are stacked, A lifting jig characterized in that each of the two longitudinal members is formed from a square steel pipe, the lower member is attached to the lower surface of the steel pipe, and the upper member is attached to the upper surface of the steel pipe.

2. A lifting jig as described in claim 1, characterized in that lifting rings are provided at at least four locations on the load, taking into account the center of gravity, and the load-side wire connected to the lifting rings is connected to the lifting hole.

3. 3. The lifting jig according to claim 1, wherein the load to be lifted is a deck slab.

4. A method for lifting a load with a crane using a lifting jig, comprising: The hanging jig, Two longitudinal members that are connected in a crossing manner and stacked one on top of the other at the center in the longitudinal direction; a lower member provided on each of the two longitudinal members in two regions between the connection position in the center of the longitudinal direction and both ends of the longitudinal direction, the lower member having a plurality of hoisting holes formed at intervals in the longitudinal direction to which load-side wires connected to the hoisting load are connected; and an upper member provided on each of the two longitudinal members at two positions equidistant from the connection position toward both ends in the longitudinal direction, to which a crane side wire connected to the crane is connected, In each of the lower members provided in the two regions of each of the two longitudinal members, the load-side wire is connected to any one of the plurality of lifting holes, and the crane-side wire is connected to each of the upper members provided in the two positions of each of the two longitudinal members, and in a state in which the load is lifted by the crane via the lifting jig, the crossing angle of the two longitudinal members is freely changed so that it is set to an angle set for each of the loads, The lower member is formed of a plate member extending in the longitudinal direction and protruding downward, Of the two longitudinal members, the lower member provided in the two regions of the upper longitudinal member and the lower member provided in the two regions of the lower longitudinal member are arranged so that their lower edges are at the same height in the vertical direction in which the two longitudinal members are stacked, and the multiple hanging holes of both are formed at the same height, Of the two longitudinal members, the upper member provided at the two positions of the upper longitudinal member and the upper member provided at the two positions of the lower longitudinal member are connected to the crane side wire at the same height in the vertical direction in which the two longitudinal members are stacked, A lifting method characterized in that each of the two longitudinal members is formed from a square steel pipe, the lower member is attached to the underside of the steel pipe, and the upper member is attached to the upper surface of the steel pipe.

5. A lifting method as described in claim 4, characterized in that lifting rings are provided at at least four locations on the load, taking into account the center of gravity, and the load-side wire connected to the lifting rings is connected to the lifting hole.

6. 6. The lifting method according to claim 4 or 5, wherein the load to be lifted is a deck slab.

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