Suspended scaffolding

Abstract

The objective is to provide a suspended scaffolding system that minimizes the gap formed between the construction surface and the construction surface, even when the construction surface intersects diagonally with a line horizontally connecting the construction objects in a plan view, without requiring the use of beams of different axial lengths. [Solution] To solve the above problem, a frame is provided having four beam members and four joints, the joints having connecting members 30 that can selectively connect the ends of the beam members in a state that allows or restricts horizontal rotation, the connecting members 30 having a pair of first connection points P1, P1 that are provided on a first straight line L1 that is on the same circumference of a virtual circle C and passes through the center of the virtual circle C in a plan view and can connect the ends of the beam members 2, and a pair of second connection points P2, P2 that are provided on a second straight line L2 that is on the same circumference of a virtual circle C and passes through the center of the virtual circle C and can connect the ends of the beam members 2, the angle between the first straight line L1 and the second straight line L2 is less than 90 degrees.

Description

Technical Field

[0001] The present invention relates to a suspended scaffold.

Background Art

[0002] As a conventional suspended scaffold, for example, there is one that is suspended from a structure such as a bridge or a building and used for construction work on the structure or building (see, for example, Patent Document 1).

[0003] Specifically, the suspended scaffold disclosed in Patent Document 1 includes a frame body formed in a square shape with four beam members and four joints connecting ends of the respective beam members, suspension members for suspending the frame body, and a floor plate installed on the frame body. Further, in the suspended scaffold disclosed in Patent Document 1, even in a state suspended from a structure or the like, by connecting beam members to the joints, another frame body can be attached to each side of the square frame body, and the floor plate area can be expanded by installing a floor plate on the attached frame body.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] In such a suspended scaffold, since the floor plate area is expanded by attaching another frame body to each side of the square frame body, the overall shape of the suspended scaffold can only be a shape formed by adding squares vertically and horizontally.

[0006] When such a suspended scaffold is installed on a bridge that has a bridge girder and a plurality of bridge piers each having a rectangular cross-section and supporting the bridge girder, the suspended scaffold is expanded along the extending direction of the bridge girder in a state where the suspended scaffold is arranged between the two bridge piers, so that the overall shape of the suspended scaffold is a rectangle.

[0007] Therefore, when the bridge pier is installed in a direction perpendicular to the extension direction of the bridge girder, the surface of the bridge pier that is horizontally opposite to the end of the suspended scaffolding (hereinafter referred to as the "construction target surface") is parallel to the end of the suspended scaffolding, and the end of the suspended scaffolding is aligned with the construction target surface. As a result, when the suspended scaffolding is extended to the vicinity of the bridge pier, the gap between the construction target surface and the end of the suspended scaffolding can be reduced.

[0008] However, due to geographical constraints, it is sometimes necessary to install bridge piers at an angle to the extension direction of the bridge girder. In such cases, the surface to be constructed is not parallel to the end of the suspended scaffolding, and the end of the suspended scaffolding does not align with the surface to be constructed on the bridge pier, resulting in a trapezoidal gap between the end of the suspended scaffolding and the surface to be constructed.

[0009] If such a gap exists between the end of the suspended scaffolding and the surface of the bridge pier being constructed, workers cannot safely perform maintenance work on the surface from atop the suspended scaffolding. Therefore, conventionally, beams of different lengths were connected to each joint at the end of the suspended scaffolding, and beams were then placed diagonally across the ends of these beams along the surface of the construction, thereby adding a trapezoidal frame to the end of the suspended scaffolding and filling the gap between the end of the suspended scaffolding and the surface of the construction.

[0010] However, when adding a trapezoidal frame to the end of a suspended scaffolding in this way, it is necessary to prepare separate beams with different axial lengths from the beams that make up the square frame. This resulted in extra costs such as transportation costs for transporting multiple types of beams to the construction site and production costs for manufacturing multiple types of beams.

[0011] Therefore, the present invention aims to provide a suspended scaffold that can reduce the gap formed between the scaffold and the surface to be constructed without having to prepare beam members of different axial lengths. [Means for solving the problem]

[0012] To achieve the above objective, the suspended scaffold of the present invention comprises a frame formed in a rectangular shape in plan view, having four beam members and four joints connecting the ends of the beam members; a suspension member for suspending the frame; and a floor plate supported by the frame. The joint has a connecting member that can selectively connect the ends of the beam members in either a state where horizontal rotation is permitted or a state where horizontal rotation is restricted. The connecting member has a pair of first connection points provided at two locations on the same circumference of a virtual circle in plan view and on a first straight line passing through the center of the virtual circle, to which the ends of the beam members can be connected, and a pair of second connection points provided at two locations on the same circumference of a virtual circle and on a second straight line passing through the center of the virtual circle and intersecting the first straight line, to which the ends of the beam members can be connected. The first intersection angle, which is the smaller of the angles made by the first straight line and the second straight line, is less than 90 degrees. With this configuration, by connecting the ends of the beam members to the first and second connection points to form a frame, the frame can be made into a parallelogram shape inclined at an angle equal to the first intersection angle. Furthermore, since the first and second connection points are located on the same circumference of a virtual circle, the axial lengths of all the beam members constituting the frame can be made the same. Therefore, when installing the suspended scaffolding of the present invention between two construction objects, even if the construction surfaces of the construction objects are positioned to intersect diagonally in a plan view with a straight line horizontally connecting the two construction objects, setting the first intersection angle to the same angle as the inclination angle of the construction surface or an angle at least closer to the inclination angle of the construction surface than 90 degrees allows the frame to conform to the construction surface better than if the frame were square or rectangular. Thus, even if the construction surfaces are positioned to intersect diagonally in a plan view with a straight line horizontally connecting the two construction objects, the gap formed between the suspended scaffolding and the construction surface can be reduced without preparing beam members with different axial lengths.

[0013] Furthermore, in the suspended scaffolding of the present invention, the connecting member has a pair of third connection points provided at two locations on the same circumference of a virtual circle and on a third line passing through the center of the virtual circle and intersecting the first line, to which the ends of the beam members can be connected. The second intersection angle, which is the smaller of the angles formed by the first line and the third line, may be less than 90 degrees and different from the first intersection angle. With this configuration, when the ends of the beam members are connected to the first connection point and the third connection point of the connecting member of each joint to form a frame, the frame can be made into a parallelogram shape inclined at an angle of inclination equal to the second intersection angle. Since the second intersection angle is less than 90 degrees and different from the first intersection angle, by selecting whether to connect the ends of the beam members to the second connection point or the third connection point, frame members with different angles of inclination can be formed. Therefore, the angle of inclination of the frame can be selected to match the angle of inclination of the surface to be constructed. Therefore, even when performing maintenance work on construction surfaces with different inclination angles, the same type of suspended scaffolding equipped with the same joints can be used, making the suspended scaffolding of the present invention highly versatile.

[0014] Furthermore, in the suspended scaffolding of the present invention, the second and third connection points may be positioned on the arcs of separate sectors among the four sectors formed by dividing the virtual circle with a first straight line and a fourth straight line that intersects the first straight line at a right angle through the center of the virtual circle. With this configuration, since the second and third connection points are spaced apart in the circumferential direction, the second and third connection points do not interfere with each other even if the first and second intersection angles are close. Therefore, the degree of freedom for the first and second intersection angles is increased, and the design freedom for the inclination angle of the frame is improved.

[0015] Furthermore, in the suspended scaffolding of the present invention, the connecting member may have a pair of fourth connection points provided at two locations on the same circumference of a virtual circle and on a fourth straight line that passes through the center of the virtual circle and intersects the first straight line at a right angle, to which the ends of the beam members can be connected. With this configuration, a square frame can be formed by connecting the ends of the beam members to the first connection point and the fourth connection point of the connecting member of each joint. Therefore, when the construction target surface is set up so as to intersect the straight line horizontally connecting the two construction target surfaces at a right angle, or when the inclination angle of the construction target surface is closer to 90 degrees than the first intersection angle, forming the frame in a square shape can reduce the gap formed between the frame of the suspended scaffolding and the construction target surface.

[0016] Furthermore, in the suspended scaffolding of the present invention, the first intersection angle may be 45 degrees. With this configuration, when the joint is rotated 90 degrees in the circumferential direction, the positions of the first and fourth connection points are swapped, and only the inclination direction of the second line is reversed. Therefore, by simply selecting the circumferential orientation of the joint and whether to connect the ends of the beam members to the first and second connection points or the third and fourth connection points, two types of parallelogram-shaped frames can be easily formed, with the inclination angle remaining 45 degrees but only the inclination direction being reversed. Moreover, since there is no need to go to the trouble of creating a new connection point at the intersection of the line perpendicular to the second line and the virtual circle, in order to form frames with the same inclination angle but only the inclination direction being reversed, the processing cost of the joint can be reduced.

[0017] Furthermore, in the suspended scaffold of the present invention, the first intersection angle is an angle other than 45 degrees, and the connecting member has a pair of fifth connection points that can connect the ends of beam members, provided at two locations on the same circumference of a virtual circle and on a fifth straight line that passes through the center of the virtual circle and intersects the first straight line, and the second and fifth connection points are arranged on the arc of the same sector among the four sectors formed by dividing the virtual circle with the first and fourth straight lines, and the third intersection angle, which is the smaller of the angles made between the fourth and fifth straight lines, may be equal to the first intersection angle. With this configuration, when the joint is rotated 90 degrees in the circumferential direction, the positions of the first and fourth connection points are swapped, and the fifth straight line intersects the fourth straight line, which is swapped in position with the first straight line, at a third intersection angle equal to the second inclination angle, while the inclination direction is reversed. Therefore, by simply selecting the circumferential orientation of the joint and whether to connect the ends of the beam members to the first and third connection points or the fourth and fifth connection points of each joint, two types of parallelogram-shaped frames can be easily formed, where the inclination angle remains the same as the second or third intersection angle, but only the direction of inclination is reversed. [Effects of the Invention]

[0018] According to the suspended scaffolding of the present invention, even if the construction surface is positioned so as to intersect diagonally in a plan view with a straight line horizontally connecting two construction objects, the gap formed between the construction surface and the beam material can be reduced without having to prepare beam materials of different axial lengths. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a plan view of a suspended scaffold with a frame inclination angle of 45 degrees. [Figure 2] Figure 2 is a side view of the suspended scaffolding installed on the bridge, seen from the side. [Figure 3] Figure 3 is a schematic diagram of a suspended scaffolding installed between the piers of a bridge, viewed from above. [Figure 4] Figure 4 is a side view of a beam in a suspended scaffold. [Figure 5]Figure 5 is a front view of a beam member in a suspended scaffold. [Figure 6] Figure 6 is an enlarged side view showing a part of the beam member in the suspended scaffold. [Figure 7] Figure 7 is a perspective view of a joint in the suspended scaffold. [Figure 8] Figure 8 is an enlarged perspective view showing a state where a chain as a hanging member is fixed to the joint in the suspended scaffold. [Figure 9] Figure 9 is an enlarged side view showing a portion where the beam member and the joint are connected in the suspended scaffold. [Figure 10] Figure 10 is a plan view of the joint in the suspended scaffold. [Figure 11] Figure 11(A) is a plan view showing a state where ends of beam members are connected respectively to a first connection point and a second connection point of the joint in the suspended scaffold. Figure 11(B) is a plan view showing a state where the ends of the beam members are connected respectively to a second connection point and a fourth connection point in a state where the joint in the suspended scaffold is rotated 90 degrees in the circumferential direction from the state shown in Figure 11(A). [Figure 12] Figure 12(A) is a plan view showing a state where ends of beam members are connected respectively to a first connection point and a third connection point of the joint in the suspended scaffold. Figure 12(B) is a plan view showing a state where the ends of the beam members are connected respectively to a fourth connection point and a fifth connection point in a state where the joint in the suspended scaffold is rotated 90 degrees in the circumferential direction from the state shown in Figure 12(A). [Figure 13] Figure 13 is a plan view of the suspended scaffold in which the inclination angle of the frame body is 60 degrees. [Figure 14] Figure 14 is a plan view showing a state where ends of beam members are connected to a first connection point and a fourth connection point of the joint in the suspended scaffold. [Figure 15] Figure 15(A) is a plan view of an auxiliary beam in the suspended scaffold. Figure 15(B) is a side view of the auxiliary beam in the suspended scaffold. [Figure 16] Figure 16 is an enlarged plan view showing a connecting portion between the auxiliary beam and the beam member in the suspended scaffold. [Modes for carrying out the invention]

[0020] This embodiment will be described below with reference to the drawings. The same reference numerals used throughout the drawings indicate the same part.

[0021] As shown in Figures 1, 2, and 3, the suspended scaffolding 1 according to this embodiment is constructed by connecting a plurality of scaffolding units A in the front-to-back and left-to-right directions. As shown in Figures 1 and 2, each scaffolding unit A comprises a frame 4 formed in a rectangular shape in plan view, having four beam members 2 and four joints 3 connecting the ends of the beam members 2; a chain 5 as a suspension member for suspending the frame 4; and a floor plate 6 supported by the frame 4. As shown in Figure 1, four scaffolding units A are connected in the front-to-back and left-to-right directions to form one suspended scaffolding 1, and adjacent scaffolding units A in the front-to-back or left-to-right direction share beam members 2 and joints 3. By connecting one scaffolding unit A to another scaffolding unit A, the floor plate area of ​​the suspended scaffolding 1 can be expanded in the front-to-back or left-to-right direction. Such a suspended scaffolding 1 is suspended from a building or structure via the chain 5, providing scaffolding to workers performing construction or maintenance work on the building or structure. Note that in Figure 1, in order to make the structure of the frame 4 of the suspended scaffolding 1 easier to understand, the floorboards 6 installed on the two lower frame 4 in the figure have been omitted from the illustration.

[0022] Furthermore, in the suspended scaffolding 1 of this embodiment shown in Figure 1, the frame 4 is assembled in a parallelogram shape in plan view (hereinafter simply referred to as "parallelogram shape"), but it can also be assembled in a square or rectangle shape by changing the connection state of the beam members 2 and joints 3 and the length of the beam members 2. Moreover, since the floor area can be expanded by connecting the parallelogram-shaped frame 4 in the front-to-back direction or left-to-right direction in plan view, the overall shape of the suspended scaffolding 1 can also be formed in a parallelogram shape in plan view.

[0023] When such a suspended scaffolding 1 is used, for example, for maintenance work on a bridge 10, as shown in Figure 2, the suspended scaffolding 1 is suspended from the lower end of the bridge girder 10a of the bridge 10 via a chain 5 and positioned between two of the multiple bridge piers 10b, 10b that support the bridge girder 10a. In this case, as shown in Figures 1, 2, and 3, the suspended scaffolding 1 is installed so that the parallelogram-shaped frame 4 can be extended in both the left-right direction (the extension direction of the bridge girder 10a) and the front-back direction (a direction that intersects diagonally with the extension direction of the bridge girder 10a in a plan view).

[0024] Furthermore, by extending the floor area of ​​the suspended scaffolding 1 along the extension direction of the bridge girder 10a (left-right direction in Figure 2) to the vicinity of the two bridge piers 10b, 10b, the end of the suspended scaffolding 1 can be positioned very close to the bridge piers 10b. Therefore, workers can perform maintenance work on the underside of the bridge girder 10a and the surface of the bridge pier 10b that is horizontally opposite to the end of the suspended scaffolding 1 (construction target surface 10b1) from the suspended scaffolding 1.

[0025] Here, if pier 1b is installed at an angle to the extension direction of girder 1a in a plan view, the construction target surface 10b1 of pier 10b intersects at an angle to the extension direction of girder 10a (the straight line horizontally connecting the two piers 10b, 10b) in a plan view, as shown in Figure 3.

[0026] Even in such a case, if the frame 4 can be assembled so that the beam member 2, which is positioned in a direction that crosses the bridge girder 10a (front-to-back direction) in a plan view, is parallel to the construction target surface 10b1 of the bridge pier 10b, the gap between the end of the suspended scaffolding 1 and the construction target surface 10b1 can be reduced compared to the case where the end of the suspended scaffolding 1 is at an angle to the construction target surface 10b1. As described above, since the suspended scaffolding 1 of this embodiment can form the frame 4 in a parallelogram shape, if the inclination angle of the frame 4 (the smaller of the vertex angles of the frame 4) is set to be the same as the inclination angle of the construction target surface 10b1 (the smaller of the angles made between the straight line horizontally connecting the two bridge piers 10b, 10b and the construction target surface 10b1), or at least closer to the inclination angle of the construction target surface 10b1 than 90 degrees, the frame 4 can be made to conform to the construction target surface 10b1 more closely than when the frame 4 is a square or rectangle (when the angle made between the beam members 2, 2 in the frame 4 is 90 degrees), thereby reducing the gap between the suspended scaffolding 1 and the construction target surface 10b1. Note that the construction target surface 10b1 is not limited to the outer periphery of the bridge piers 10b of the bridge 10, but may be, for example, the outer periphery of a column supporting the roof of a building.

[0027] The following describes in detail each part of the scaffolding unit A that constitutes the suspended scaffolding 1. As shown in Figure 1, the frame 4 is formed in a rectangular shape in plan view, having four beam members 2 and four joints 3 that connect the ends of each beam member 2.

[0028] As shown in Figure 4, the beam member 2 comprises an upper chord member 20 and a lower chord member 21 arranged parallel to each other vertically, and a plurality of diagonal members 22 that are placed diagonally between the upper chord member 20 and the lower chord member 21 to connect them, thus forming a truss structure. In addition, both ends of the upper chord member 20 and the lower chord member 21 are provided with connecting parts 23 that can be connected to the joint 3.

[0029] As shown in Figure 5, the upper chord member 20 is provided with a pair of upper support pieces 20a, 20a with an L-shaped cross-section, extending along the longitudinal direction of the beam member 2. Specifically, each upper support piece 20a is formed in an L-shape with a bottom portion 20a1 extending along the longitudinal direction of the beam member 2 and a vertical portion 20a2 projecting vertically upward from the inner end of the bottom portion 20a1 (the end on the other upper support piece 20a side). The vertical portions 20a2 are positioned facing each other, with the bottom portions 20a1 projecting outward from each other. Furthermore, as shown in Figure 1, the bottom portion 20a1 of each upper support piece 20a of the upper chord member 20 is provided with holes 20a3 at three locations: the center in the longitudinal direction, the portion between the center and one end, and the portion between the center and the other end, to which the ends of the auxiliary beam 7, which will be described later, can be connected.

[0030] As shown in Figure 5, the lower chord member 21 comprises a pair of L-shaped lower support pieces 21a, 21a extending along the longitudinal direction of the beam member 2. Specifically, each lower support piece 21a is formed in an L-shape with a bottom portion 21a1 extending along the longitudinal direction of the beam member 2 and a vertical portion 21a2 projecting vertically downward from the inner end of the bottom portion 21a1 (the end on the other lower support piece 21a side). The vertical portions 21a2 are positioned facing each other, with the bottom portions 21a1 projecting outward from each other.

[0031] The upper chord member 20 and the lower chord member 21, configured in this way, are connected by multiple diagonal members 22. Specifically, the upper end of each diagonal member 22 is welded in place while inserted between the upper support pieces 20a, 20a, and the lower end of each diagonal member 22 is welded in place while inserted between the lower support pieces 21a, 21a, thereby connecting the upper chord member 20 and the lower chord member 21.

[0032] As shown in Figure 6, the connecting section 23 includes a rectangular tubular connecting member 23a, which is connected between the upper support pieces 20a, 20a and the lower support pieces 21a, 21a on both sides of the longitudinal direction of the beam member 2, with its upper and lower ends inserted between them, respectively, and spanned between the upper chord member 20 and the lower chord member 21; and a pair of upper and lower connecting pieces 23b, 23b that extend from the upper and lower ends of the connecting member 23a along the longitudinal direction of the beam member 2 and protrude outward from one end of the upper chord member 20 and the lower chord member 21. Each connecting piece 23b is provided with a first mounting hole 23b1 located at the tip and a second mounting hole 23b2 located at the base, at predetermined intervals, with the first mounting holes 23b1, 23b1 and the second mounting holes 23b2, 23b2 facing each other vertically. Note that in Figure 6, the thickness of the connecting piece 23b is thin, making it difficult to show the first mounting hole 23b1 and the second mounting hole 23b2 with dashed lines; therefore, the first mounting hole 23b1 and the second mounting hole 23b2 are shown with solid lines.

[0033] Furthermore, the connecting section 23 is provided with a pair of upper and lower flat support pieces 23c, 23c that are positioned between the connecting pieces 23b, 23b and extend from the connecting member 23a along the longitudinal direction of the beam member 2, facing the connecting pieces 23b, 23b vertically. The support pieces 23c are provided with a first insertion hole 23c1 that faces the first mounting hole 23b1 of the connecting piece 23b vertically, and a second insertion hole 23c2 that faces the second mounting hole 23b2 of the connecting piece 23b vertically. The connecting section 23 also includes a cylindrical connecting pipe 23d that is supported at each end by the respective support pieces 23c and spans between the pair of support pieces 23c, 23c. Both ends of the connecting pipe 23d each face the first insertion hole 23c1, and the inside of the connecting pipe 23d is in communication with the first insertion hole 23c1. In Figure 6, the thickness of the support piece 23c is thin, making it difficult to show the first insertion hole 23c1 and the second insertion hole 23c2 with dashed lines; therefore, the first insertion hole 23c1 and the second insertion hole 23c2 are shown with solid lines.

[0034] Furthermore, the connecting section 23 includes a pair of left and right reinforcing beams 23e, 23e that are diagonally placed between the connecting member 23a and the connecting pipe 23d. With this configuration, the connecting section 23 becomes a truss structure with the connecting member 23a, the connecting pipe 23d and the reinforcing beams 23e, 23e, thereby increasing the strength of the connecting section 23.

[0035] Next, the joint 3 of this embodiment will be described in detail. The joint 3 includes a connecting member 30 that can selectively connect the ends of the beam members 2 in either a state where horizontal rotation is permitted or a state where horizontal rotation is restricted. Specifically, as shown in Figure 7, the connecting member 30 has a pair of upper and lower plates 31 and 32 arranged in parallel, and a cylindrical connecting tube portion 33 that connects the upper plate 31 and the lower plate 32. In addition, a U-shaped handle 34 is provided on the outer circumference of the connecting tube portion 33, which functions as a handle when carrying the joint 3.

[0036] In this embodiment, the upper plate 31 and the lower plate 32 are circular plate materials, and as shown in Figures 7 and 8, a chain fixing hole 35 is provided in the center of the upper plate 31 to which the lower end of the chain 5 can be connected. The chain 5 is formed by connecting a plurality of annular chain elements 5a in a chain. Hereinafter, the side of the chain element 5a facing the hole will be referred to as the front side, the width of the chain element 5a (horizontal chain element 5a) when viewed from the front side will be referred to as the width, and the width of the chain element 5a (vertical chain element 5a) when viewed from the side side will be referred to as the height.

[0037] As shown in Figures 7 and 8, the chain fixing hole 35 has a central hole 35a through which the chain 5 is inserted, four ribbed holes 35b extending radially from the central hole 35a at 90-degree intervals, and notched grooves 35c that cross the extension direction of each ribbed hole 35b. The width of the ribbed holes 35b is wider than the vertical width of the chain element 5a and narrower than the horizontal width of the chain element 5a.

[0038] Then, as shown in Figure 8, with the chain 5 inserted through the central hole 35a, the chain 5 is moved horizontally toward the ribbed hole 35b, and the vertical chain elements 5a of the chain 5 are inserted into the ribbed hole 35b, causing the upper plate 31 to be inserted between the two horizontal chain elements 5a, 5a. Since the width of the ribbed hole 35b is narrower than the width of the horizontal chain elements 5a (the width of the chain elements 5a), the ribbed hole 35b does not allow the horizontal chain elements 5a to pass through in the vertical direction. Therefore, when the chain 5 is moved upward relative to the joint 3 with the vertical chain elements 5a inserted into the ribbed hole 35b, the upper plate 31 is supported by the horizontal chain elements 5a of the chain 5, so the joint 3 can be lifted by the chain 5.

[0039] Then, with the chain 5 inserted into the rib hole 35b, inserting the fixing plate 36 into the notched groove 35c restricts the horizontal movement of the chain 5, preventing it from coming out of the rib hole 35b. Furthermore, in this embodiment, the fixing plate 36 and the chain 5 are secured by passing the restraining band 37 through the hole 36a provided on the upper end side of the fixing plate 36 and through the chain element 5a of the chain 5, thus preventing the fixing plate 36 from falling off and allowing the joint 3 to be safely lifted by the chain 5.

[0040] In this embodiment, the lower end of the chain 5 is connected to the joint 3 in this manner, but the above-described method of connecting the chain 5 is just one example, and the method of connecting the chain 5 is not particularly limited as long as it can suspend the frame 4. The lower end of the chain 5 may also be connected to the beam 2. Furthermore, the suspension material for suspending the frame 4 is not limited to the chain 5, but may be, for example, a wire.

[0041] Furthermore, as shown in Figure 7, the upper plate 31 and the lower plate 32 are each provided with 10 pin holes 31a and 32a, respectively, which are arranged on the same circumference in a plan view and face each other vertically. In addition, arc-shaped anti-rotation grooves 31b and 32b are provided on the outer circumference of the upper plate 31 and the lower plate 32 at positions radially opposite to each pin hole 31a and 32a when viewed from the center of each plate 31 and 32. The shapes of the upper plate 31 and the lower plate 32 are not particularly limited and may be, for example, rectangular. Similarly, the shape of the connecting cylinder portion 33 is not limited to a cylindrical shape and may be, for example, a rectangular cylinder.

[0042] Then, as shown in Figure 9, the upper plate 31 is inserted between the upper connecting piece 23b and the upper support piece 23c at the connection portion 23 of the beam member 2, and the lower plate 32 is inserted between the lower connecting piece 23b and the lower support piece 23c, so that the pin holes 31a and 32a of each plate 31 and 32, the first mounting hole 23b1 of each connecting piece 23b, the first insertion hole 23c1 of each support piece 23c and the inside of the connecting pipe 23d are opposed to each other vertically. In this state, by inserting the fixing pin 11 into the first mounting hole 23b1, the pin holes 31a and 32a, the first insertion hole 23c1 of the support piece 23c and the connecting pipe 23d, the end of the beam member 2 is connected to the joint 3 in a manner that allows for horizontal rotation.

[0043] Furthermore, when the beam member 2, which is rotatably connected to the joint 3 by the fixing pin 11, is positioned on the line connecting the pin holes 31a, 32a and the anti-rotation grooves 31b, 32b, the anti-rotation grooves 31b, 32b face the second mounting hole 23b2 of the connecting piece 23b and the second insertion hole 23c2 of the support piece 23c.

[0044] Therefore, when the fixing pin 11 is inserted into the first mounting hole 23b1, the pin holes 31a, 32a, and the connecting pipe 23d, and the beam member 2 is positioned on the line connecting the pin holes 31a, 32a and the anti-rotation grooves 31b, 32b, and the anti-rotation pin 12 is inserted into the second mounting hole 23b2 and the second insertion hole 23c2, the anti-rotation pin 12 is also inserted into the anti-rotation grooves 31b, 32b. As a result, the joint 3 and the beam member 2 are connected by two axes, so that the end of the beam member 2 is connected to the joint 3 in a manner that restricts horizontal rotation. Note that the anti-rotation grooves 31b, 32b formed in the plates 31, 32 could also be holes, but since they are grooves provided on the outer circumference of the plates 31, 32, the outer diameter of the plates 31, 32 becomes smaller. Therefore, the amount of material for the plates 31, 32 is reduced, and the joint 3 can be made lighter.

[0045] Next, based on the description in Figure 10, the positions of the 10 pin holes 31a in the upper plate 31 will be explained. The positions of the 10 pin holes 32a in the lower plate 32 are the same as the positions of the pin holes 31a in the upper plate 31, so the explanation will be omitted.

[0046] First, as shown in Figure 10, when the upper plate 31 is viewed from directly above, a circle with a smaller diameter than the upper plate 31 and sharing the same center as the upper plate 31 is defined as a virtual circle C. The first straight line L1 is a straight line passing through the center of the virtual circle C along the left-right direction in the figure. The second straight line L2 is a straight line that passes through the center of the virtual circle C and whose first intersection angle θ1, the smaller of the angles it makes with the first straight line L1, is 45 degrees. The third straight line L3 is a straight line that passes through the center of the virtual circle C and whose second intersection angle θ2, the smaller of the angles it makes with the first straight line L1, is 60 degrees. The fourth straight line L4 is a straight line that passes through the center of the virtual circle C along the up-down direction in the figure and intersects the first straight line L1 at a right angle. The fifth straight line L5 is a straight line that passes through the center of the virtual circle C and whose third intersection angle θ3, the smaller of the angles it makes with the fourth straight line L4, is 60 degrees. Although the above explanation stated that the angle between the fifth line L5 and the fourth line L4 is 60 degrees, since the fifth line L5 passes between the first line L1 and the fourth line L4, which intersect at a right angle, it can also be said that the angle between the fifth line L5 and the first line L1 is 30 degrees.

[0047] Furthermore, as shown in Figure 10, when two locations on the same circumference of the virtual circle C and on the first straight line L1 are referred to as the first connection points P1, P1, two locations on the same circumference of the virtual circle C and on the second straight line L2 are referred to as the second connection points P2, P2, two locations on the same circumference of the virtual circle C and on the third straight line L3 are referred to as the third connection points P3, P3, two locations on the same circumference of the virtual circle C and on the fourth straight line L4 are referred to as the fourth connection points P4, P4, and two locations on the same circumference of the virtual circle C and on the fifth straight line L5 are referred to as the fifth connection points P5, P5, the ten pin holes 31a are each positioned so that their centers coincide with each of the connection points P1, P2, P3, P4, and P5. In other words, the 10 pinholes 31a are located at 10 points, each corresponding to an intersection of the virtual circle C and the respective lines L1, L2, L3, L4, and L5.

[0048] As mentioned above, as shown in Figure 9, by inserting fixing pins 11 into the first mounting hole 23b1, the first insertion hole 23c1 and the connecting pipe 23d of the connecting portion 23 provided at the end of the beam member 2, and into the pin holes 31a and 32a of the plates 31 and 32 in the joint 3, the end of the beam member 2 can be connected to the joint 3 while allowing horizontal rotation. Therefore, each connection point P1, P2, P3, P4, and P5 where the pin holes 31a and 32a are located is a connection point where the end of the beam member 2 can be connected.

[0049] The method of connecting the ends of the beam member 2 to connection points P1, P2, P3, P4, and P5 is not particularly limited, and connection points P1, P2, P3, P4, and P5 are any connection points that allow the ends of the beam member 2 to be connected so as to be rotatable in the horizontal direction. For example, a pin portion that stands upright along the vertical direction may be provided at each connection point P1, P2, P3, P4, and P5, and the beam member 2 may be placed over the pin portion from above, so that the pin portion is inserted into the first mounting hole 23b1, the first insertion hole 23c1, and the connecting pipe 23d provided in the connecting portion 23 of the beam member 2.

[0050] Furthermore, the inclination angle of the frame 4 (the smaller of the apex angles of the frame 4) can be arbitrarily changed depending on which connection points P1, P2, P3, P4, and P5 of the connecting member 30 in the joint 3 are used to connect the ends of the beam member 2 to form the frame 4.

[0051] Specifically, in the frame 4 shown in Figure 1, as shown in Figure 11(A), the ends of the beam members 2 are connected to the first connection point P1 and the second connection point P2 of the connecting member 30 at each joint 3. Here, as shown in Figure 10, the first connection point P1 is located at the intersection of the virtual circle C and the first straight line L1, which passes through the center of the virtual circle C in the left-right direction in a plan view. The second connection point P2 is located at the intersection of the virtual circle C and the second straight line L2, which intersects the first straight line L1 at a first intersection angle θ1 of 45 degrees in a plan view and also passes through the center of the virtual circle C, and is sloping upwards to the right in the figure. Therefore, as shown in Figure 11(A), the beam members 2 whose ends are connected to the first connection point P1 of each joint 3 extend in the left-right direction in the figure, and the beam members 2 whose ends are connected to the second connection point P2 of each joint 3 extend from the joint 3 at a 45-degree angle in the upper-right direction in the figure relative to the left-right direction.

[0052] Therefore, when the ends of the beam members 2 are connected to the first connection points P1 and the second connection points P2 of the connecting member 30 at each joint 3 to form a frame 4, the frame 4 will have an inclination angle of 45 degrees and will be a parallelogram shape tilted to the right in the figure, as shown in Figure 1. In other words, the inclination angle of the frame 4 formed by connecting the ends of the beam members 2 to the first connection points P1 and the second connection points P2 at each joint 3 will be equal to the first intersection angle θ1.

[0053] Furthermore, as shown in Figure 10, the connecting member 30 of the joint 3 in this embodiment has a fourth connection point P4 located at the intersection of the virtual circle C and a fourth straight line L4 that passes through the center of the virtual circle C and intersects the first straight line L1 at a right angle. Also, since the angle between the second straight line L2 and the first straight line L1 (first intersection angle θ1) is 45 degrees, the angle between the second straight line L2 and the fourth straight line L4 is also 45 degrees.

[0054] Therefore, when the joint 3, which is positioned as shown in Figure 10, is rotated 90 degrees in the circumferential direction, the positions of the first connection point P1 and the fourth connection point P4 are swapped, as shown in Figure 11(B), and the second straight line L2 reverses only in its inclination direction, becoming inclined upward to the left in Figure 11(B) at a 45-degree angle to the fourth straight line L4.

[0055] Therefore, as shown in Figure 11(B), when the ends of the beam members 2 are connected at each joint 3 to the second connection points P2 located at the intersection of the second straight line L2 and the virtual circle C, and to the fourth connection points P4 located at the intersection of the fourth straight line L4 and the virtual circle C, respectively, to form a frame 4, the frame 4 will have a parallelogram shape that remains at a 45-degree inclination angle and tilts to the opposite side (left side in Figure 1) from the frame 4 shown in Figure 1.

[0056] In other words, according to this embodiment, by simply selecting the circumferential orientation of the joint 3 and whether to connect the ends of the beam members 2 to the first connection point P1 and the second connection point P2 or the third connection point P3 and the fourth connection point P4 of each joint 3, it is possible to easily form two types of parallelogram-shaped frames 4, with the inclination angle remaining unchanged from 45 degrees (first intersection angle θ1) and only the inclination direction (the direction in which a pair of opposing beam members 2,2 in the frame 4 inclins with respect to the joint 3) being reversed.

[0057] Furthermore, according to this embodiment, in order to form a frame 4 with the same inclination angle but opposite inclination direction, it is not necessary to create a new connection point at the intersection of the line that intersects the second line L2 of the connecting member 30 at a right angle with the virtual circle C, to which the end of the beam member 2 can be connected.

[0058] Furthermore, as shown in Figure 10, the connecting member 30 of the joint 3 in this embodiment is provided with a third connection point P3 at the intersection of the virtual circle C and a third straight line L3, which passes through the center of the virtual circle C in a plan view, rising to the left in the figure, and intersects the first straight line L1 at a second intersection angle θ2 of 60 degrees.

[0059] Therefore, as shown in Figure 12(A), when the ends of the beam members 2 are connected to the first connection points P1 and the third connection points P3 of the connecting member 30 at each joint 3 to form a frame 4, the beam member 2 connected to the first connection point P1 extends along the left-right direction in the figure, and the beam member 2 connected to the third connection point P3 extends at an angle of 60 degrees to the upper left in the figure relative to the left-right direction. Thus, as shown in Figure 13, the frame 4 has an inclination angle of 60 degrees and is a parallelogram shape tilted to the left in the figure. In other words, the inclination angle of the frame 4 formed by connecting the ends of the beam members 2 to the first connection point P1 and the third connection point P3 at each joint 3 is equal to the second intersection angle θ2. Furthermore, since the second intersection angle θ2 is different from the first intersection angle θ1, when the ends of the beam members 2 are connected to the first connection points P1 and the third connection points P3 of the connecting member 30 at each joint 3 to form the frame 4, a frame 4 with a different inclination angle from the frame 4 shown in Figure 1 can be formed. Note that in Figure 13, the floorboards 6 installed on the two lower frame 4 in the figure are omitted in order to make the structure of the frame 4 of the suspended scaffolding 1 easier to understand.

[0060] Furthermore, as shown in Figure 10, the connecting member 30 of the joint 3 in this embodiment is provided with a fifth connection point P5 at the intersection of the virtual circle C and the fifth straight line L5, which passes through the center of the virtual circle C in a plan view, rising to the left in the figure, and intersects the fourth straight line L4 at a third intersection angle θ3 of 60 degrees.

[0061] Furthermore, if we consider that the fifth line L5, like the third line L3, is inclined upward to the left in Figure 10, then, as shown in Figure 10, when the virtual circle C is divided into four sectors by the first line L1 and the fourth line L4 that intersect it at right angles, and of the two pairs of sectors that are positioned on either side of the center of the virtual circle C, the pair of sectors in the upper left and lower right of the figure is called the first sector Ca,Ca, and the pair of sectors in the upper right and lower left of the figure is called the second sector Cb,Cb, then it can be said that the fifth connection point P5 is located on the same arc of the first sector Ca,Ca as the third connection point P3.

[0062] Thus, in the connecting member 30 of the joint 3 of this embodiment, the fifth connection point P5 is positioned on the same arc of the first sector Ca,Ca as the third connection point P3, and the third intersection angle θ3, which is the angle between the fourth line L4 and the fifth line L5, is equal to the second intersection angle θ2, which is the angle between the first line L1 and the third line L3. Therefore, when the joint 3, which is positioned as shown in Figure 10, is rotated 90 degrees in the circumferential direction, the fourth line L4 becomes aligned in the left-right direction in a plan view, as shown in Figure 12(B), and the fifth line L5 is inclined at an angle of 60 degrees upward to the right in a plan view relative to the fourth line L4.

[0063] Therefore, as shown in Figure 12(B), when the ends of the beam members 2 are connected at each joint 3 to the fourth connection points P4 located at the intersection of the fourth straight line L4 and the virtual circle C, and to the fifth connection points P5 located at the intersection of the fifth straight line L5 and the virtual circle C, respectively, to form a frame 4, the frame 4 will have a parallelogram shape that remains at an inclination angle of 60 degrees and tilts to the opposite side (to the right in Figure 13) from the frame 4 shown in Figure 13.

[0064] In other words, according to the frame 4 of this embodiment, by simply selecting the circumferential orientation of the joint 3 and whether to connect the end of the beam member 2 to the first connection point P1 and third connection point P3 or the fourth connection point P4 and fifth connection point P5 of each joint 3, two types of parallelogram-shaped frame 4 can be easily formed, in which the inclination angle remains the same as the second intersection angle θ2 or the third intersection angle θ3, but only the inclination direction is reversed.

[0065] Furthermore, if the joint 3, positioned as shown in Figure 12(A), is rotated 60 degrees counterclockwise in the circumferential direction (the same angle as the second intersection angle θ2), the third straight line L3 will align with the left-right direction in a plan view, and the fourth straight line L4 will be inclined at a 60-degree angle upward to the right in a plan view relative to the third straight line L3 which aligns with the left-right direction. Therefore, in this state, if the ends of the beam members 2 are connected to the third connection point P3 and the fourth connection point P4 to form the frame 4, it is possible to form a parallelogram-shaped frame 4 that has the same inclination angle as the frame 4 shown in Figure 13 but tilts to the opposite side (the right side in Figure 13), without providing pin holes 31a and 32a at the fifth connection point P5.

[0066] However, as shown in Figures 12(A) and (B), aligning either the first straight line L1 or the fourth straight line L4, which intersect at a right angle, in the left-right direction (the direction of extension of the bridge girder 1a) makes the arrangement of joint 3 more intuitive than aligning the third straight line L3, which passes between the first straight line L1 and the fourth straight line L4, in the left-right direction. Therefore, as shown in Figures 12(A) and (B), aligning either the first straight line L1 or the fourth straight line L4 in the left-right direction and connecting the ends of the beam members 2 to the first connection point P1 or the fourth connection point P4 and the third connection point P3 or the fifth connection point P5, respectively, makes it less likely to make assembly errors such as connecting the ends of the beam members 2 to the wrong connection points. In particular, in this embodiment, the first connection point P1 and the fourth connection point P4 are positioned on the extension of the rib hole 35b of the chain fixing hole 35, and the positions of the first connection point P1 positioned on the first straight line L1 and the fourth connection point P4 positioned on the fourth straight line L4 are easy to understand, making it easy to position the joint 3 so that the first straight line L1 or the fourth straight line L4 is aligned in the left-right direction.

[0067] Although not explained in detail here, as mentioned above, the second intersection angle θ2, which is the angle between the first line L1 and the third line L3, and the third intersection angle θ3, which is the angle between the fourth line L4 and the fifth line L5, are both 60 degrees. Therefore, the angle between the third line L3 and the fourth line L4 and the angle between the first line L1 and the fifth line L5 are both 30 degrees. Consequently, the frame 4 formed by connecting the ends of the beam members 2 to the first connection point P1 and the fifth connection point P5 with the joint 3 positioned so that the first line L1 is aligned in the left-right direction in a plan view, and the frame 4 formed by connecting the ends of the beam members 2 to the third connection point P3 and the fourth connection point P4 with the joint 3 positioned so that the fourth line L4 is aligned in the left-right direction in a plan view, both have an inclination angle of 30 degrees and are parallelogram shapes with opposite inclination directions. In other words, in this embodiment, the frame 4 can also be made into a parallelogram shape with an inclination angle of 30 degrees.

[0068] Furthermore, in this embodiment, as shown in Figure 14, the first straight line L1 and the fourth straight line L4 intersect at a right angle. Therefore, by connecting the ends of the beam members 2 to the first connection point P1 located at the intersection of the first straight line L1 and the virtual circle C, and to the fourth connection point P4 located at the intersection of the fourth straight line L4 and the virtual circle C, respectively, a frame 4 is formed. In plan view, the frame 4 will be a square shape with the angles between the beam members 2 being 90 degrees.

[0069] Thus, in the suspended scaffolding 1 of this embodiment, the frame 4 can be formed into a parallelogram or square shape that is inclined at an inclination angle of 30, 45, or 60 degrees in any direction, depending on which connection point P1, P2, P3, P4, P5 of the connecting member 30 in the joint 3 to which the end of the beam member 2 is connected.

[0070] Therefore, when the suspended scaffolding 1 of this embodiment is installed on a bridge 10 where the construction target surface 10b1 of the bridge pier 10b is arranged to intersect diagonally with the extension direction of the bridge girder 10a, as shown in Figure 3, the frame 4 can be formed at the same or closer inclination angle as the construction target surface 10b1. In other words, by selecting the inclination angle of the frame 4 to match the inclination angle of the construction target surface 10b1, the gap formed between the frame 4 and the construction target surface 10b1 can be reduced. Thus, even when performing maintenance work on construction target surfaces 10b1 with different inclination angles, the suspended scaffolding 1 equipped with the same joint 3 can be used, making the suspended scaffolding 1 of this embodiment highly versatile.

[0071] Furthermore, if the bridge piers 10b are installed such that the surface to be constructed 10b1 intersects the extension direction of the bridge girder 10a at a right angle in a plan view (a straight line horizontally connecting the two bridge piers 10b, 10b), or if the inclination angle of the surface to be constructed 10b1 is closer to 90 degrees than the first intersection angle θ1 and the second intersection angle θ2, forming the frame 4 in a square shape will reduce the gap formed between the frame 4 and the surface to be constructed 10b1.

[0072] Furthermore, in the suspended scaffolding 1 configured in this way, each connection point P1, P2, P3, P4, and P5 are arranged on the same circumference of the virtual circle C. Therefore, the horizontal distances between the first connection point P1, P1, the second connection point P2, P2, the third connection point P3, P3, the fourth connection point P4, P4, and the fifth connection point P5, P5, where the ends of each beam member 2 in the frame 4 are connected, are all equal. Thus, it is possible to form parallelogram-shaped or square-shaped frames 4 with different inclination angles while using beam members 2 of the same length. In other words, regardless of the parallelogram-shaped or square-shaped frame 4 with different inclination angles, all beam members 2 constituting the frame 4 can be made to have the same axial length. Therefore, it is not necessary to prepare beam members 2 with different axial lengths in order to reduce the gap between the frame 4 and the construction target surface 10b1, thus reducing the costs associated with transporting and producing the beam members 2.

[0073] Furthermore, in this embodiment, the selectable inclination angles of the frame 4 are 30 degrees, 45 degrees, and 60 degrees. However, the selectable inclination angles of the frame 4 are not particularly limited, and it is possible to form a frame 4 with any inclination angle by changing the design of the installation locations of the connection points P1, P2, P3, P4, and P5. Specifically, since the inclination angle of the frame 4 is determined by the magnitudes of the first intersection angle θ1, the second intersection angle θ2, and the third intersection angle θ3 of the connecting member 30 in the joint 3, the inclination angle of the frame 4 can be freely set by appropriately determining the circumferential positions of each connection point P1, P2, P3, P4, and P5 on the virtual circle C so that the first intersection angle θ1, the second intersection angle θ2, and the third intersection angle θ3 are any angles. Note that the first intersection angle θ1, the second intersection angle θ2, and the third intersection angle θ3 are not particularly limited as long as they are less than 90 degrees.

[0074] Furthermore, in the connecting member 30 of the joint 3 of this embodiment, as shown in Figure 10, the third connection point P3 and the fifth connection point P5 are arranged on the same arc of the first sector Ca, Ca on the virtual circle C, and the second connection point P2 is arranged on the arc of the second sector Cb, Cb on the virtual circle C. As a result, each connection point P1, P2, P3, P4, P5 is distributed circumferentially on the virtual circle C, so when pin holes 31a, 32a are provided at each connection point P1, P2, P3, P4, P5, it is possible to prevent the pin holes 31a, 32a from concentrating on a part of the connecting member 30, thus preventing the creation of a weak part in a part of the connecting member 30.

[0075] Furthermore, if the second connection point P2, the third connection point P3, and the fifth connection point P5 are to be placed on the same sector arc (first sector Ca or second sector Cb) on the virtual circle C, then the second connection point P2, the third connection point P3, and the fifth connection point P5 must be spaced apart in the circumferential direction to the extent that the pin holes 31a and 32a provided in the second connection point P2, the third connection point P3, and the fifth connection point P5, respectively, do not interfere with each other. In that case, the degrees of freedom for the first intersection angle θ1, the second intersection angle θ2, and the third intersection angle θ3 will decrease, thus reducing the design freedom for the inclination angle of the frame 4.

[0076] In contrast, in this embodiment, the second connection point P2, the third connection point P3, and the fifth connection point P5 are arranged on the arcs of the second sector Cb and the first sector Ca, which are separate sectors on the virtual circle C, and the second connection point P2, the third connection point P3, and the fifth connection point P5 are spaced apart in the circumferential direction, so the degrees of freedom for the first intersection angle θ1, the second intersection angle θ2, and the third intersection angle θ3 are increased, and the design freedom for the inclination angle of the frame 4 is improved. However, if there is no problem of insufficient strength of the connecting member 30 in the joint 3, the second connection point P2, the third connection point P3, and the fifth connection point P5 may be arranged on the arc of the same sector (first sector Ca or second sector Cb) on the virtual circle C.

[0077] Furthermore, if the strength of the connecting member 30 in joint 3 is sufficient, additional pin holes 31a, 32a may be provided, for example, on the virtual circle C between the first connection point P1 and the second connection point P2, to serve as connection points that allow the ends of the beam members 2 to be connected, thereby increasing the variations in the inclination angle of the frame 4. If variations in the inclination angle of the frame 4 are not necessary, it is sufficient for the connecting member 30 in joint 3 to have at least the first connection point P1 and the second connection point P2, so the third connection point P3, the fourth connection point P4, and the fifth connection point P5 may be omitted.

[0078] Furthermore, in the suspended scaffolding 1 of this embodiment, as shown in Figures 1 and 13, three auxiliary beams 7 are placed at predetermined intervals between opposing beam members 2, 2 in the frame 4 in one direction, the vertical direction in the figures, and are spanned parallel to opposing beam members 2, 2 in the other direction, the horizontal direction in the figures. Since these auxiliary beams 7 support the floorboards 6, which will be described later, together with the frame 4, providing the auxiliary beams 7 increases the support strength of the suspended scaffolding 1 and increases the load capacity. However, the number of auxiliary beams 7 is not particularly limited and can be increased or decreased as appropriate according to the load capacity of the suspended scaffolding 1.

[0079] As shown in Figure 15, the auxiliary beam 7 comprises an auxiliary beam body 70 and mounting portions 71 provided at both ends of the auxiliary beam body 70 in the longitudinal direction. More specifically, the auxiliary beam body 70 comprises a main body portion 70a with a rectangular cross-section that extends along the left-right direction in Figure 15(B), horizontal plate portions 70b that extend horizontally (up-down direction in Figure 15(A)) from both ends of the upper end of the main body portion 70a in the short direction, and projection portions 70c that rise from the center of the upper part of the main body portion 70a and extend along the longitudinal direction of the main body portion 70a.

[0080] Furthermore, as shown in Figure 15, the mounting portion 71 includes a flat vertical piece 71a extending along the height direction (up and down direction in Figure 15(B)) of the end of the main body portion 70a of the auxiliary beam body 70, side plate pieces 71b extending vertically from both ends of the vertical piece 71a and connected to the end of the main body portion 70a with bolts, a flat horizontal piece 71c extending from the upper end of the vertical piece 71a toward the side opposite the auxiliary beam body, and a pin body 71d that penetrates the tip portion of the horizontal piece 71c vertically.

[0081] As shown in Figures 1 and 13, the auxiliary beam 7 configured in this way is spanned between the pair of beam members 2, 2 facing each other vertically in the figure, in a position parallel to the beam member 2 facing each other horizontally in the figure, by inserting the pin bodies 71d of each mounting part 71 into holes 20a3 provided in the bottom 20a1 of the upper support piece 20a of the pair of beam members 2, 2 facing each other vertically in the figure.

[0082] In this embodiment, the horizontal piece 71c of the mounting portion 71 of the auxiliary beam 7 has a rounded triangular tip portion 71c1 with a vertex angle of 90 degrees at its tip end, as shown in Figure 16(A), and a pin body 71d is positioned near the vertex of the tip portion 71c1. Then, as shown by the solid line in Figure 16, when the auxiliary beam 7 is connected to the beam member 2 in a vertical position in a plan view, the angle between each side extending from the vertex of the tip portion 71c1 and the vertical portion 20a2 that protrudes vertically upward from the bottom portion 20a1 of the upper support piece 20a of the beam member 2 is 45 degrees. Therefore, even if the auxiliary beam 7 is rotated around the pin body 71d from a state where it is connected to the beam member 2 in a vertical position, the horizontal piece 71c of the mounting portion 71 of the auxiliary beam 7 will not interfere with the vertical portion 20a2 of the beam member 2 as long as it is within a 45-degree range to the left and right from the vertical position. In other words, as shown by the dashed line in Figure 16, the auxiliary beam 7 is connected to the beam member 2 in a perpendicular position and is allowed to rotate up to 45 degrees to the left and right around the pin body 71d as an axis.

[0083] As shown in Figure 1, when the auxiliary beam 7 is placed between the beam members 2, 2 in a frame 4 with an inclination angle of 45 degrees, the auxiliary beam 7 will be inclined at a 45-degree angle with respect to the beam members 2. Therefore, the auxiliary beam 7 will be in a position that is 45 degrees rotated from the position in which it was connected perpendicularly to the beam members 2. Also, as shown in Figure 13, when the auxiliary beam 7 is placed between the beam members 2, 2 in a frame 4 with an inclination angle of 60 degrees, the auxiliary beam 7 will be inclined at a 60-degree angle with respect to the beam members 2. Therefore, the auxiliary beam 7 will be in a position that is 30 degrees rotated from the position in which it was connected perpendicularly to the beam members 2. Thus, the auxiliary beam 7 of this embodiment can be placed between the beam members 2, 2 in the frame 4 regardless of whether the inclination angle of the frame 4 is 45 degrees or 60 degrees. Therefore, the same auxiliary beam 7 can be used for frame 4 with different inclination angles, eliminating the need to prepare a separate auxiliary beam to match the inclination angle of the frame 4, and reducing the costs associated with transporting and producing the auxiliary beam 7. If the inclination angle of the frame 4 is less than 60 degrees, the size of the apex angle of the tip portion 71c1 of the horizontal piece 71c should be appropriately set to match the inclination angle of the frame 4. For example, if an auxiliary beam 7 is installed on a frame 4 formed at an inclination angle of 30 degrees, the apex angle of the tip portion 71c1 of the horizontal piece 71c should be set to 60 degrees.

[0084] However, the shape of the horizontal piece 71c is not particularly limited if there is no vertical piece 20a2 on the upper support piece 20a of the beam member 2, or if the horizontal piece 71c does not interfere with the vertical piece 20a2 even if the mounting portion 71 of the auxiliary beam 7 rotates around the pin body 71d. Furthermore, the auxiliary beam 7 may be omitted if the strength of the suspended scaffolding 1 against load is sufficient.

[0085] Furthermore, as shown in Figures 1 and 13, the floorboard 6 is composed of four boards 6a installed in two locations between the left and right beam members 2,2 and the left and right auxiliary beams 7,7 in the frame 4, and in two locations between the three auxiliary beams 7. Each board 6a is a parallelogram shape with the same inclination angle as the frame 4 and is supported by the beam members 2 and the auxiliary beams 7. Although not shown, if the frame 4 is formed in a square shape, floorboards composed of four rectangular boards can be installed between the beam members 2 and the auxiliary beams 7 and between the auxiliary beams 7,7.

[0086] Furthermore, each of the boards 6a constituting the floorboard 6 is surrounded by the vertical portion 20a2 of the beam 2 constituting the frame 4 and the projection 70c of the auxiliary beam 7. Therefore, the horizontal movement of the boards 6a is restricted. The number of boards 6a constituting the floorboard 6 is not particularly limited, and if the auxiliary beam 7 does not have projections 70c, the floorboard 6 may be formed from a single board.

[0087] As described above, the suspended scaffolding 1 of this embodiment comprises a frame 4 formed in a rectangular shape in plan view, having four beam members 2 and four joints 3 connecting the ends of the beam members 2, a chain 5 as a suspension member for suspending the frame 4, and a floor plate 6 supported by the frame 4. The joints 3 have connecting members 30 that can selectively connect the ends of the beam members 2 in either a state where horizontal rotation is permitted or a state where horizontal rotation is restricted, and the connecting members 30 are the same circle of the virtual circle C in plan view. The structure includes a pair of first connection points P1, P1 located at two locations on the circumference of the virtual circle C and on a first straight line L1 passing through the center of the virtual circle C, to which the ends of the beam member 2 can be connected, and a pair of second connection points P2, P2 located at two locations on the same circumference of the virtual circle C and on a second straight line L2 passing through the center of the virtual circle C and intersecting the first straight line L1, to which the ends of the beam member 2 can be connected, and the first intersection angle θ1, which is the smaller of the angles made between the first straight line L1 and the second straight line L2, is set to less than 90 degrees.

[0088] In the suspended scaffolding 1 configured in this way, when the ends of the beam members 2 are connected to the first connection point P1 and the second connection point P2 of the connecting member 30 of each joint 3 to form a frame 4, the frame 4 can be made into a parallelogram shape inclined at an angle of inclination equal to the first intersection angle θ1. Furthermore, since the first connection point P1 and the second connection point P2 are located on the same circumference of the virtual circle C, the axial lengths of all the beam members 2 constituting the frame 4 can be made the same. Therefore, when installing the suspended scaffolding 1 between two bridge piers 10b, 10b as construction targets, even if the construction target surface 10b1 of the bridge pier 10b is positioned so as to intersect diagonally in a plan view with respect to the extension direction of the bridge girder 10a (a straight line horizontally connecting the two bridge piers 10b, 10b), if the first intersection angle θ1 is set to the same angle as the inclination angle of the construction target surface 10b1 or at least closer to the inclination angle of the construction target surface 10b1 than 90 degrees, the frame 4 can be aligned more closely with the construction target surface 10b1 than when the frame 4 is square or rectangular (when the angle between the beam members 2, 2 in the frame 4 is 90 degrees). Thus, according to the suspended scaffolding 1 of this embodiment, even if the construction target surface 10b1 is positioned so as to intersect diagonally in a plan view with respect to the extension direction of the bridge girder 10a, the gap formed between the suspended scaffolding 1 and the construction target surface 10b1 can be reduced without preparing beam members 2 with different axial lengths.

[0089] Furthermore, in the suspended scaffolding 1 of this embodiment, the connecting member 30 has a pair of third connection points P3, P3 that are provided at two locations on the same circumference of the virtual circle C and on the third straight line L3 that passes through the center of the virtual circle C and intersects the first straight line L1, and the ends of the beam members 2 can be connected, and the second intersection angle θ2, which is the smaller of the angles made between the first straight line L1 and the third straight line L3, is less than 90 degrees and different from the first intersection angle θ1.

[0090] With the suspended scaffolding 1 configured in this way, by connecting the ends of the beam members 2 to the first connection point P1 and the third connection point P3 of the connecting member 30 of each joint 3, respectively, a frame 4 can be formed, making the frame 4 a parallelogram shape inclined at an angle equal to the second intersection angle θ2. Since the second intersection angle θ2 is less than 90 degrees and different from the first intersection angle θ1, by selecting whether to connect the ends of the beam members 2 to the second connection point P2 or the third connection point P3, frame 4 with different angles of inclination can be formed. Therefore, the angle of inclination of the frame 4 can be appropriately selected to match the angle of inclination of the construction target surface 10b1. Thus, even when performing maintenance work on a construction target surface 10b1 with different angles of inclination, the suspended scaffolding 1 equipped with the same joints 3 can be used, making the suspended scaffolding 1 of this embodiment highly versatile.

[0091] Furthermore, in the suspended scaffolding 1 of this embodiment, the second connection point P2 and the third connection point P3 are respectively located on the arcs of the four sectors formed by dividing the virtual circle C with a first straight line L1 and a fourth straight line L4 that passes through the center of the virtual circle C and intersects the first straight line L1 at a right angle.

[0092] With the suspended scaffolding 1 configured in this way, the second connection point P2 and the third connection point P3 are spaced apart in the circumferential direction. Therefore, even if the first intersection angle θ1 and the second intersection angle θ2 are close angles, the second connection point P2 and the third connection point P3 do not interfere with each other. Thus, the degrees of freedom for the first intersection angle θ1 and the second intersection angle θ2 are increased, improving the design freedom for the inclination angle of the frame 4. However, the second connection point P2 and the third connection point P3 may be placed on the same sector arc in the virtual circle C.

[0093] Furthermore, in the suspended scaffolding 1 of this embodiment, the connecting member 30 has a pair of fourth connection points P4 that are provided at two locations on the same circumference of the virtual circle C and on a fourth straight line L4 that passes through the center of the virtual circle C and intersects the first straight line L1 at a right angle, and to which the ends of the beam members 2 can be connected.

[0094] With the suspended scaffolding 1 configured in this way, a square frame 4 can be formed by connecting the ends of the beam members 2 to the first connection point P1 and the fourth connection point P4 of the connecting member 30 of each joint 3. Therefore, if the construction target surface 10b1 is installed so as to intersect the extension direction of the bridge girder 10a (the straight line horizontally connecting the two bridge piers 10b, 10b) at a right angle, or if the inclination angle of the construction target surface 10b1 is closer to 90 degrees than the first intersection angle θ1 and the second intersection angle θ2, forming the frame 4 in a square shape can reduce the gap formed between the frame 4 of the suspended scaffolding 1 and the construction target surface 10b1.

[0095] Furthermore, in the suspended scaffolding 1 of this embodiment, the first intersection angle θ1 is 45 degrees. In the suspended scaffolding 1 configured in this way, when the joint 3 is rotated 90 degrees in the circumferential direction, the positions of the first connection point P1 and the fourth connection point P4 are swapped, and only the inclination direction of the second straight line L2 is reversed. Therefore, by simply selecting the circumferential orientation of the joint 3 and whether to connect the end of the beam member 2 to the first connection point P1 and the second connection point P2 or the third connection point P3 and the fourth connection point P4, two types of parallelogram-shaped frames 4 can be easily formed, with the inclination angle remaining 45 degrees but only the inclination direction being reversed.

[0096] Furthermore, since it is not necessary to create a new connection point at the intersection of the line that intersects the second line L2 at a right angle with the virtual circle C, solely to form a frame 4 with the same inclination angle but opposite inclination direction, the processing cost of the joint 3 can be reduced. Note that the first intersection angle θ1 is not limited to 45 degrees as long as it is less than 90 degrees, and may be determined, for example, in accordance with the inclination angle of the surface to be constructed 10b1.

[0097] Furthermore, in the suspended scaffolding 1 of this embodiment, the second intersection angle θ2 is 60 degrees, which is an angle other than 45 degrees, and the connecting member 30 has a pair of fifth connection points P5 that can connect the ends of the beam members 2, provided at two locations on the same circumference of the virtual circle C and on the fifth straight line L5 that passes through the center of the virtual circle C and intersects the first straight line L1, and the second connection point P2 and the fifth connection point P5 are arranged on the arc of the same sector among the four sectors formed by dividing the virtual circle C with the first straight line L1 and the fourth straight line L4, and the third intersection angle θ3, which is the smaller of the angles made between the fourth straight line L4 and the fifth straight line L5, is equal to the second intersection angle θ2.

[0098] In the suspended scaffolding 1 configured in this way, when the joint 3 is rotated 90 degrees in the circumferential direction, the positions of the first connection point P1 and the fourth connection point P4 are swapped, and the fifth straight line L5 intersects the fourth straight line L4, which is swapped with the first straight line L1, at a third intersection angle θ3 equal to the second intersection angle θ2, while the direction of inclination is reversed. Therefore, by simply selecting the circumferential orientation of the joint 3 and whether to connect the ends of the beam members 2 to the first connection point P1 and the third connection point P3 or the fourth connection point P4 and the fifth connection point P5 of each joint 3, two types of parallelogram-shaped frames 4 can be easily formed, in which the inclination angle remains the same as the second intersection angle θ2 or the third intersection angle θ3, but only the direction of inclination is reversed.

[0099] Furthermore, in the suspended scaffolding 1 configured in this way, the first straight line L1 or the fourth straight line L4, which intersect at a right angle, are aligned with the extension direction of the bridge girder 1a. This makes the arrangement of the joints 3 intuitively easy to understand, and reduces the likelihood of assembly errors such as incorrectly connecting the ends of the beam members 2 at the wrong connection points.

[0100] In this embodiment, the second intersection angle θ2 and the third intersection angle θ3 are set to 60 degrees. However, the second intersection angle θ2 and the third intersection angle θ3 are not particularly limited as long as they are less than 90 degrees and not 45 degrees. By simply selecting the circumferential orientation of the joint 3 and whether to connect the end of the beam member 2 to the first connection point P1 and the third connection point P3 or the fourth connection point P4 and the fifth connection point P5 of each joint 3, two types of parallelogram-shaped frames 4 can be easily formed, where the inclination angle remains the same as the second intersection angle θ2 or the third intersection angle θ3, but only the direction of inclination is reversed.

[0101] Furthermore, although this embodiment has been described using the case where the first intersection angle θ1 is 45 degrees as an example, the first intersection angle θ1 may be set to an angle other than 45 degrees. In that case, the connecting member 30 is provided with a pair of fifth connection points P5, P5 that can be used to connect the ends of the beam member 2 at two locations on the same circumference of the virtual circle C and on the fifth line L5 that passes through the center of the virtual circle C and intersects the first line L1. The second connection point P2 and the fifth connection point P5 are placed on the arc of the same sector among the four sectors formed by dividing the virtual circle C with the first line L1 and the fourth line L4. The smaller of the angles made by the fourth line L4 and the fifth line L5 is set as the third intersection angle θ3, and the third intersection angle θ3 may be set to be equal to the first intersection angle θ1.

[0102] In the suspended scaffolding 1 configured in this way, when the joint 3 is rotated 90 degrees in the circumferential direction, the positions of the first connection point P1 and the fourth connection point P4 are swapped, and the fifth straight line L5 intersects the fourth straight line L4, which has been swapped with the first straight line L1, at a third intersection angle θ3 equal to the first intersection angle θ1, while the direction of inclination is reversed. Therefore, by simply selecting the circumferential orientation of the joint 3 and whether to connect the ends of the beam members 2 to the first connection point P1 and the second connection point P2 or the fourth connection point P4 and the fifth connection point P5 of each joint 3, two types of parallelogram-shaped frames 4 can be easily formed, in which the inclination angle remains the same as the first intersection angle θ1 or the third intersection angle θ3, but only the direction of inclination is reversed.

[0103] Furthermore, if variations in the inclination angle of the frame 4 are not required, it is sufficient to provide at least the first connection point P1 and the second connection point P2, so the third connection point, the fourth connection point P4, and the fifth connection point P5 may be omitted.

[0104] Furthermore, in the suspended scaffolding 1 of this embodiment, the connecting member 30 has arc-shaped anti-rotation grooves 31b and 32b, respectively, which are positioned on a straight line in the radial direction of each connection point P1, P2, P3, P4, and P5 when viewed from the center. The virtual circle passing through the center of each anti-rotation groove 31b and 32b is concentric with the virtual circle C on which the connection points P1, P2, P3, P4, and P5 are located. With this configuration, since the distance from each connection point P1, P2, P3, P4, and P5 to the center of each anti-rotation groove 31b and 32b is equal, the points on the beam member 2 that are fixed to the anti-rotation grooves 31b and 32b are in the same position in the axial direction. Therefore, the structure for fixing the beam member 2 to each anti-rotation groove 31b and 32b (second mounting hole 23b2 and second insertion hole 23c2) can be common. Therefore, since it is not necessary to provide multiple structures (second mounting holes 23b2 and second insertion holes 23c2) for connecting to the anti-rotation grooves 31b and 32b on the beam member 2, a decrease in the strength of the beam member 2 can be prevented, and the number of processing steps is reduced, making it easier to manufacture the beam member 2.

[0105] Note that the anti-rotation grooves 31b and 32b could also be holes, but in this example they are grooves provided on the outer circumference of plates 31 and 32, which reduces the outer diameter of plates 31 and 32. Therefore, the amount of material used for plates 31 and 32 is reduced, making the joint 3 lighter.

[0106] Although preferred embodiments of the present invention have been described in detail above, it goes without saying that modifications, alterations, and changes can be made without departing from the scope of the claims. [Explanation of Symbols]

[0107] 1...Suspended scaffolding, 2...Beam material, 3...Joint, 4...Frame, 5...Chain (suspension material), 6...Floorboard, 30...Connecting member, C...Virtual circle, Ca,Cb...Second sector, L1...First straight line, L2...Second straight line, L3...Third straight line, L4...Fourth straight line, L5...Fifth straight line, P1...First connection point, P2...Second connection point, P3...Third connection point, P4...Fourth connection point, P5...Fifth connection point, θ1...First intersection angle, θ2...Second intersection angle, θ3...Third intersection angle

Claims

1. A frame having four beam members and four joints connecting the ends of the beam members, which is formed in a rectangular shape in plan view, A suspension member for suspending the aforementioned frame, The frame comprises a floor plate supported by the frame, The joint has a connecting member that can selectively connect the ends of the beam material in either a state where horizontal rotation is permitted or a state where horizontal rotation is restricted. The aforementioned connecting member is A pair of first connection points are provided at two locations on the same circumference of a virtual circle in a plan view and on a first straight line passing through the center of the virtual circle, and the ends of the beam member can be connected to these points. It has a pair of second connection points provided at two locations on the same circumference of the virtual circle and on a second line passing through the center of the virtual circle and intersecting the first line, to which the ends of the beam member can be connected. The first intersection angle, which is the smaller of the angles formed by the first straight line and the second straight line, is less than 90 degrees. A suspended scaffold characterized by the following features.

2. The connecting member has a pair of third connection points provided at two locations on the same circumference of the virtual circle and on a third line passing through the center of the virtual circle and intersecting the first line, which can connect the ends of the beam member. The second intersection angle, which is the smaller of the angles formed by the first line and the third line, is less than 90 degrees and different from the first intersection angle. The suspended scaffolding according to feature 1.

3. The second and third connection points are respectively positioned on the arcs of the four sectors formed by dividing the virtual circle with the first line and a fourth line that passes through the center of the virtual circle and intersects the first line at a right angle. The suspended scaffolding according to feature 2.

4. The connecting member has a pair of fourth connection points provided at two locations on the same circumference of the virtual circle and on a fourth line that passes through the center of the virtual circle and intersects the first line at a right angle, enabling the ends of the beam members to be connected. The suspended scaffolding according to feature 1.

5. The first intersection angle is 45 degrees. The suspended scaffolding according to feature 4.

6. The first intersection angle is an angle other than 45 degrees, The connecting member has a pair of fifth connection points provided at two locations on the same circumference of the virtual circle and on a fifth straight line that passes through the center of the virtual circle and intersects the first straight line, and is capable of connecting the ends of the beam material. The second and fifth connection points are positioned on the arc of the same sector among the four sectors formed by dividing the virtual circle with the first and fourth lines. The third intersection angle, which is the smaller of the angles formed by the fourth and fifth lines, is equal to the first intersection angle. The suspended scaffolding according to feature 4.

Images