Metal fitting for temporary scaffolding

Abstract

To provide a metal fitting for assembling a temporary scaffold, which can be utilized when the temporary scaffold is assembled by combining a vertical temporary steel pipe support and an erection member having an end fixed to the support.SOLUTION: A cylindrical bearing member 8 fixed to one end of a thick-plate body 7 constituting the pressing member 3 is fitted between both side plate portions of the side 2a of the rising end portion of the wide base member 2, and the pressing member 3 is pivotally supported by a support shaft 10 penetrating the cylindrical bearing member 8 so as to be freely opened and closed. The fastening bolt-nut 4 is journaled by a support shaft 11 between both side plate parts of a lower side free end part side 2b of the wide base member 2 so as to be freely fitted to and removed from a U-shaped member 9 installed in a free end part of the thick plate bookbinding body 7, and a wedge driving recessed part 13 is formed in the thick plate bookbinding body 7.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to temporary scaffolding assembly fittings that can be used when assembling temporary scaffolding by combining vertically oriented temporary steel pipe supports and erection members whose ends are fixed to the supports. [Background technology]

[0002] Temporary scaffolding is assembled by combining vertically oriented temporary steel pipe supports and horizontally oriented erection members that are perpendicular to the supports. To assemble such temporary scaffolding, four vertically oriented temporary steel pipe supports are placed adjacent to the four corners of a rectangular scaffolding board (panel) of a predetermined length, and these four temporary steel pipe supports are connected to each other using a connecting framework formed by two long erection members that run along both long sides of the rectangular scaffolding board and two short erection members that run along both short sides of the rectangular scaffolding board (both of which are generally made of steel pipes), and the temporary scaffolding is assembled by supporting the scaffolding board using this connecting framework. Fastening bolts and fastening wedges have traditionally been used to assemble such temporary scaffolding. One example, as described in Patent Document 1, is a known retrofit temporary scaffolding assembly hardware. The hardware consists of two semicircular members, each split into two thick disk-shaped plates, pivotally connected so that they can be opened and closed. The two semicircular members grip a temporary steel pipe support from both sides, and fastening bolts and nuts are provided to fasten the free ends of the two semicircular members together. Other retrofit temporary scaffolding assembly hardware is also known, with the scaffolding assembly hardware welded to the temporary steel pipe support to match the scaffolding plate installation height. While patent documents cannot be disclosed, one example is a wedge-tightening scaffold sold by Sugitaka Co., Ltd. under the product name "Albatross." In either type of temporary scaffolding assembly fittings, the fittings attached to the temporary steel pipe supports have wedge holes that penetrate in the vertical direction, and the ends of the erection members are supported at the locations where the wedge holes of the fittings are provided. A wedge body is pressed in from above downward so as to pass through the vertical wedge holes provided in the ends of the erection members and the wedge holes of the fittings, and the ends of the erection members are fixed to the temporary steel pipe supports via the wedge body and the fittings. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-67354 Summary of the Invention [Problem to be solved by the invention]

[0004] Among the conventional temporary scaffolding assembling metal fittings described above, the former metal fitting described in Patent Document 1 and the latter metal fitting welded and fixed to a temporary steel pipe support have problems that cannot be overlooked from a practical standpoint. That is, the former metal fitting described in Patent Document 1 can be attached to any position on the temporary steel pipe support, in other words, a special effect can be expected in that the erection member can be attached to any position on the temporary steel pipe support, but because it is a metal fitting that is like a single thick plate split in half, its position relative to the temporary steel pipe support is unstable and safety is significantly reduced when a great force is applied to the erection member in the vertical direction, making it difficult to say that it is optimal as a temporary scaffolding assembling metal fitting. [Means for solving the problem]

[0005] The present invention proposes a temporary scaffolding assembling hardware that can solve the above-mentioned conventional problems. To facilitate understanding of the relationship with the embodiments described below, the temporary scaffolding assembling hardware of the present invention is shown with the reference symbols used in the description of the embodiments in parentheses. The wide base member (2), a press member (3), and fastening bolts and nuts (4) are comprised of an L-shaped base member (2) in a side view, and side plate portions (6a, 6b) are bent inward from both left and right sides of an L-shaped back plate portion (5) to form a U-shaped cross section. The press member (3) is comprised of a main body (7) made of thick plate material, a cylindrical bearing member (8) fixed at a right angle to one end of the thick plate main body (7), and a U-shaped member (9) fixed to the other end of the thick plate main body (7). The press member (3) is comprised of a cylindrical bearing member (8) The bolt (4a) of the fastening bolt nut (4) is pivotally supported by a support shaft (11) between the side plate portions (6a, 6b) of the rising end portion (2a) of the wide base member (2) so as to be able to open and close freely, and the bolt (4a) of the fastening bolt nut (4) is pivotally supported by a support shaft (11) between the side plate portions (6a, 6b) of the lower free end portion (2b) of the wide base member (2) so as to be able to swing freely, and is supported in the U-shaped member (9) of the pressing member (3) so as to be able to be fitted and removed freely, and the fastening The nut (4b) of the bolt nut (4) is configured to be threaded onto the free end of the bolt (4a) and to be able to abut on the U-shaped member (9) of the holding member (3), and the thick plate body (7) of the holding member (3) is configured to have a wedge-driving recess (13) formed along an imaginary radial line passing through the center of the temporary steel pipe support (12) sandwiched between the thick plate body (7) and the wide base member (2). [Effects of the Invention]

[0006] With the temporary scaffolding assembling fittings of the present invention (hereinafter referred to as fittings of the present invention) configured as described above, when assembling temporary scaffolding by combining vertically oriented temporary steel pipe supports with erection members whose ends are fixed to the supports, the presser member and fastening bolt nuts are opened in opposite directions around the supports of the wide base member to open the inside of the wide base member, and the wide base member is then placed over the temporary steel pipe support in the position where the erection members are attached. Then, the presser member is closed to place it over the temporary steel pipe support, and the fastening bolt nuts are closed with the nuts retracted toward the free ends of the bolts to fit the bolts of the fastening bolt nuts into the U-shaped members of the presser member. At this time, if the wedge-driving recess in the hold-down member is out of position for attaching the erection member to the temporary steel pipe support, the metal fitting of the present invention is rotated around the temporary steel pipe support to adjust the position of the wedge-driving recess, and then the nuts on the fastening bolts and nuts are tightened to press the hold-down member toward the wide base member, sandwiching the temporary steel pipe support between the hold-down member and the wide base member, and fixing the metal fitting of the present invention to the temporary steel pipe support at a predetermined height and in a predetermined orientation. The subsequent attachment of the erection member using the wedge body is performed according to the well-known method described in Patent Document 1 and in the catalog for the previously mentioned "Albatross" product name, but as this is explained in detail in the examples below, a description thereof will be omitted here.

[0007] The metal fitting of the present invention can be used as described above, but the above-described configuration of the metal fitting of the present invention can be expected to have the following special effects. Specifically, because the main body of the pressure member, which has a wedge-driving recess into which a wedge is driven, is made of thick plate, a thick plate with the required strength, for example, a thickness of approximately 7 to 10 mm, can be selected. The wide base member that pivotally supports this thick plate main body so that it can be opened and closed, can be a sturdy, U-shaped cross-section with a width several times that of the thick plate main body. Furthermore, because one end of the thick plate main body is pivotally supported on the raised end of the wide base member using a support shaft that penetrates a cylindrical bearing member fixed integrally to the end of the thick plate main body, there is no need to narrow the width of the raised end of the wide base member to match the thickness of the thick plate main body. This allows one end of the thick plate main body to be easily and sturdily pivotally supported without reducing the strength of the raised end of the wide base member. Furthermore, the support shaft that pivotally supports one end of the thick plate main body so that it can be opened and closed is long enough to correspond to the width of the rising end of the wide base member, which is significantly wider than the thickness of the thick plate main body, and the support shaft is inserted into the cylindrical bearing member fixedly attached to the inner thick plate main body through the shaft holes provided in both side plates at the rising end of the wide base member, and then fixed to the wide base member in a non-removable state, making assembly simple and easy. Also, the presence of the cylindrical bearing member fixedly attached to the thick plate main body significantly reduces the play of the thick plate main body relative to the support shaft, i.e., not the play in the rotational direction relative to the support shaft, but the rocking movement of the thick plate main body due to tilting of the thick plate main body in the length direction of the support shaft, compared to when the support shaft is supported directly through the shaft hole of the thick plate main body.

[0008] Therefore, the metal fittings of the present invention, which are composed of a wide base member that is sturdy and has a wide area that is pressed against the temporary steel pipe support so that it can be easily held in the desired position with stability, and a pressing member that is made up of a sturdy thick plate main body and is axially supported on the wide base member stably without rattle, have a long service life and can be securely attached to a temporary steel pipe support for safe use.However, the greatest feature of the metal fittings of the present invention, as is clear from the usage state diagram of the example described below (Figure 4), is that the work point where the pressing member is fastened to the wide base member to secure the metal fitting of the present invention to the temporary steel pipe support, and the work point where the erection member is joined to the pressing member of the metal fitting of the present invention with a wedge, i.e., the work point where the wedge is driven into the wedge driving recess of the pressing member, are adjacent to each other on the same side of the temporary steel pipe support in a plan view. Therefore, workers can easily and efficiently attach the metal fittings of the present invention to the temporary steel pipe support from a single, approximately fixed location without having to move around the circumference of the temporary steel pipe support, and connect the erection members to the attached metal fittings of the present invention. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing the posture of a temporary scaffolding assembling fitting according to one embodiment of the present invention in use. [Figure 2] FIG. 2 is a vertical sectional front view showing the state in which the pressing member and the fastening bolt nut of the temporary scaffolding assembling metal fitting are opened. [Figure 3] 3 is a left side view of the temporary scaffolding assembling metal fitting shown in FIG. 2. FIG. [Figure 4] FIG. 4 is a plan view showing the above-mentioned temporary scaffolding assembling metal fittings in use. [Figure 5] FIG. 5 is a partial vertical cross-sectional side view of FIG. 4. [Figure 6] FIG. 6A is a left side view of a conventionally known general pipe clamp, and FIG. 6B is a front view of the same pipe clamp. [Figure 7] FIG. 7 is a vertical sectional front view of the pipe clamp. [Figure 8]FIG. 8 is a partial vertical sectional front view of a temporary scaffolding assembling fitting not belonging to the present invention, which is configured using the pressing member of the same pipe clamp. [Figure 9] FIG. 9 is a plan view showing the temporary scaffolding assembling metal fitting shown in FIG. 8 in use. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1 to 3, a temporary scaffolding assembling fitting 1 according to one embodiment of the present invention is comprised of a wide base member 2, a presser member 3, and fastening bolts and nuts 4. The wide base member 2 is L-shaped in side view, with side plates 6a, 6b bent inward from both left and right sides of the L-shaped back plate 5 to form a U-shaped cross section. The presser member 3 is comprised of a main body 7 made of thick plate material, a cylindrical bearing member 8 welded at a right angle to one end of the main body 7, and a U-shaped member 9 welded to the other end of the main body 7. The cylindrical bearing member 8 of the presser member 3 is loosely fitted between the side plates 6a, 6b at the rising end 2a of the wide base member 2, and the presser member 3 is pivotally supported on the rising end 2a of the wide base member 2 by a support shaft 10 that passes through the cylindrical bearing member 8 so as to be able to open and close freely. In addition, the bolt 4a of the fastening bolt nut 4 is pivotally supported by a support shaft 11 oriented parallel to the support shaft 10 between the side plate portions 6a, 6b where the width of the lower free end portion 2b of the wide base member 2 is narrowed, and is supported so as to be able to be freely fitted and removed between the U-shaped members 9 of the pressing member 3, and the nut 4b of the fastening bolt nut 4 is configured to be able to be screwed onto the free end portion of the bolt 4a and abut against the U-shaped member 9 of the pressing member 3.

[0011] When the wide base member 2 and the pressing member 3 are closed around the support shaft 10 to sandwich a temporary steel pipe support 12 between them as shown in Figure 7, the inner edge of the wide base member 2 (the inner edges of the side plate portions 6a, 6b) and the inner edge of the thick plate body 7 of the pressing member 3 are formed in an arc shape that roughly follows the circumferential surface of the temporary steel pipe support 12, and a wedge-driving recess 13 is cut outward in the thick plate body 7 of the pressing member 3 from approximately the center of the circumferential length of the arc-shaped inner edge of the thick plate body 7. Therefore, the outer edge of the thick plate body 7 is formed in a mountain shape that bulges outward from the inner end of the wedge-driving recess 13. The wedge-driving recess 13 is formed along an imaginary radial line passing through the center of the arc-shaped inner edge of the thick plate body 7, in other words, an imaginary radial line passing through the center of the temporary steel pipe support 12 sandwiched between the wide base member 2 and the clamping member 3.

[0012] 4 and 5, the method of using the temporary scaffolding assembling fitting 1 is explained below. At the installation position of the temporary steel pipe support 12, which will serve as the support of the temporary scaffolding, the nut 4b of the fastening bolt nut 4 is retracted toward the free end of the bolt 4a as shown in Fig. 2, and the bolt 4a is opened around the support shaft 11, and the presser member 3 is opened around the support shaft 10 to expose the inside of the wide base member 2. In this state, the inside of the wide base member 2 is brought into contact with the installation position of the temporary steel pipe support 12, which will serve as the support of the temporary scaffolding, and the presser member 3 is closed around the support shaft 10 to sandwich the temporary steel pipe support 12 between the wide base member 2 and the wide base member 2. In this state, bolt 4a of fastening bolt nut 4 is closed around support shaft 11, the free end of bolt 4a is fitted into U-shaped member 9 at the free end of pressing member 3, and finally nut 4b, which had been retracted to the free end side of bolt 4a, is screwed in, and nut 4b presses and moves U-shaped member 9 at the free end of pressing member 3 toward the base end of bolt 4a, closing pressing member 3 around support shaft 10, sandwiching temporary steel pipe support 12 between wide base member 2 and thick plate main body 7 of pressing member 3 and fixing temporary scaffolding assembly fitting 1 at a predetermined height on temporary steel pipe support 12. Care must be taken at this time to ensure that wedge-driving recess 13 provided on thick plate main body 7 of pressing member 3 is facing toward the position where the temporary member is attached to temporary steel pipe support 12.

[0013] The erection members attached to the temporary steel pipe supports 12 include horizontal steel pipes for maintaining the spacing between the temporary steel pipe supports, and steel pipes for bracing that are stretched diagonally between this horizontal steel pipe and the temporary steel pipe support 12 or between two temporary steel pipe supports 12. For example, in the case of a horizontal steel pipe 14 as shown in Figures 4 and 5, a bifurcated connecting member 15 is fixed integrally to the attachment end of the horizontal steel pipe 14 to the temporary steel pipe support 12, and can be fitted horizontally into the thick plate body 7 of the pressure member 3 of the temporary scaffolding assembly fittings 1. The bifurcated connecting member 15 is a strong, well-known casting, and its upper and lower extending portions 16, 17 are provided with elongated holes 16a, 17a for driving in wedges whose longitudinal direction coincides with the imaginary center line of the horizontal steel pipe 14, and the upper extending portion 16 is provided with a downward protrusion 16b that abuts against the upper surface of the thick plate body 7 of the holding member 3 and acts to position the thick plate body 7 of the holding member 3 at approximately the center height between the upper and lower extending portions 16, 17. Furthermore, the tips of the upper and lower extending portions 16, 17 are formed in a shape that abuts against the peripheral surface of the temporary steel pipe support 12 and regulates the fitting depth and posture of the bifurcated connecting member 15 relative to the thick plate body 7 of the holding member 3. Reference numeral 18 denotes a wedge body having a shape in which its width gradually decreases toward the lower end, which is inserted from the upper wedge-driving elongated hole 16a of the bifurcated connecting member 15 into the lower wedge-driving elongated hole 16b, and a retaining pin 19a is protruded from the upper side surface of the upper end protruding from the upper wedge-driving elongated hole 16a so as to prevent the upper wedge-driving elongated hole 16a from passing downward, and a retaining pin 19b is retrofitted to the lower side surface of the wedge body 18 protruding downward from the lower wedge-driving elongated hole 16b so as to be able to pass freely in the vertical direction through the lower wedge-driving elongated hole 16b but to be unable to pass upward into the upper wedge-driving elongated hole 16a.

[0014] When connecting a horizontal steel pipe (erection member) 14 having the bifurcated connecting member 15 of the above configuration at its tip to a temporary scaffolding assembly fitting 1 attached to a temporary steel pipe support 12 as described above, the wedge body 18 is lifted up until the lower anti-slip pin 19b reaches directly below the long hole 16a for driving the wedge in the upper extension part 16, and the bifurcated connecting member 15 is fitted from the side onto the thick plate body 7 of the pressing member 3 of the temporary scaffolding assembly fitting 1, and the tips of the upper and lower extension parts 16, 17 are abutted against the peripheral surface of the temporary steel pipe support 12, and the protrusion part 16b of the upper extension part 16 is placed on the top surface of the thick plate body 7 of the pressing member 3. In this state, the lifted wedge body 18 is lowered and its lower end is inserted downward through the wedge driving recess 13 in the thick plate body 7 of the holding member 3 and into the wedge driving slot 17a in the lower extension 17. Thereafter, the upper end of the wedge body 18 is struck downward with a hammer to press the inner and outer sides of the wedge body 18, which taper downward, against the front edges of the upper and lower wedge driving slots 16a, 17a and the back edge of the wedge driving recess 13 on the holding member 3 side, thereby press-fitting the bifurcated connecting member 15 at a predetermined height on the temporary steel pipe support 12. As a result, the horizontal steel pipe 14, which is an erection member, is attached horizontally and at a right angle to the temporary steel pipe support 12 at a predetermined height via the bifurcated connecting member 15.

[0015] Furthermore, if the erection member attached to the temporary steel pipe support 12 is a brace steel pipe that is stretched at an angle, the brace steel pipe will be connected to the bifurcated connecting member 15 so that it can swing freely up and down around the horizontal support axis.

[0016] The above-mentioned temporary scaffolding assembling fitting 1 can be constructed by simply converting the wide base member 21 and fastening bolt nut 22 of a conventional, well-known, general pipe clamp 20 shown in Figures 6 and 7 into the wide base member 2 and fastening bolt nut 4 of the present invention. The conventional pipe clamp 20 is composed of an arc-shaped pressing member 25 journaled by a support shaft 24 between both side plate portions 23a, 23b at the rising end portion 21a of the wide base member 21 so as to be able to open and close freely, and a fastening bolt nut 27 journaled by a support shaft 26 oriented parallel to the support shaft 24 between the narrowed side plate portions 23a, 23b of the lower free end portion 21b of the wide base member 21 so as to be able to swing freely. The presser member 25 of this conventional pipe clamp 20 is a wide member made by pressing a plate material into a U-shaped cross section, similar to the wide base member 21, so that one end of the presser member 25 can be fitted between the side plate portions 23a, 23b at the rising end 21a of the wide base member 21 for direct journal support, and its free end is bifurcated with a notch 25a into which the bolt 22a of the direct fastening bolt nut 22 can be freely fitted and removed. The nut 27b of the fastening bolt nut 27 abuts against the upper surfaces on both sides of the notch 25a.

[0017] The arc-shaped presser member 25 in the above-described conventional pipe clamp 20 is a wide member formed by pressing a plate material into a U-shaped cross section as described above in order to stably abut against the peripheral surface of a steel pipe, just like the wide base member 21. While its width is somewhat narrower than that of the wide base member 21, it is significantly wider than the thick plate body 7 of the presser member 3 of the present invention. Therefore, in order to pivotally support one end of the thick plate body 7 of the presser member 3 of the present invention on the rising end 21a of the wide base member 21, which currently supports one end of the wide presser member 25 with the support shaft 24, it is possible to process the rising end 21a of the wide base member 21, i.e., the distance between the both side plate portions 23a, 23b of the rising end 21a, so as to narrow it to match the width (plate thickness) of the thick plate body 7. However, rather than performing such processing, the present invention provides a method of integrally fastening a cylindrical bearing member 8, of a length that allows it to fit exactly within the width of the rising end 21a of the wide base member 21, to one end of the thick plate body 7. This not only eliminates the need for additional processing on the repurposed wide base member 21, but also significantly reduces the rocking of the thick plate body 7 relative to the wide base member 21 in a direction perpendicular to the rotational direction about the support shaft 10, due to the play between the support shaft 10 that penetrates the cylindrical bearing member 8 and both ends of the cylindrical bearing member 8. In other words, in the use state after the temporary steel pipe support 12 is fastened and fixed between the wide base member 2 and the holding member 3 with the fastening bolts and nuts 4 (see FIGS. 4 and 5 ), the thick plate body 7 of the holding member 3 can stably maintain its intended posture even against a large downward external force acting on it.

[0018] It is also possible to implement the present invention by combining the arc-shaped presser member 25 and fastening bolt nut 22 of the conventional pipe clamp 20 shown in Figures 6 and 7 with the presser member 3 of the present invention as shown in Figure 8. In a virtual temporary scaffolding assembling fitting 27 according to this embodiment, one end of the thick plate body 7 of the presser member 3 is pivotally supported by a support shaft 10 between both side plate portions at one end of the arc-shaped presser member 25 of the conventional pipe clamp 20 so as to be able to open and close freely, and a U-shaped member 28 is fixedly connected to the other end of the thick plate body 7 of the presser member 3, which pivotally supports the bolt 22a of the fastening bolt nut 22 by a support shaft 11 so as to be able to swing freely. In a hypothetical temporary scaffolding assembly fitting 27 configured in this manner, the arc-shaped pressing member 25 that supports the thick plate main body 7 of the pressing member 3 is narrower than the wide base member 21, even though it is made of plate material formed into a U-shaped cross section, and the length of the cylindrical bearing member 8 that supports the thick plate main body 7 of the pressing member 3 is also short, so it cannot be expected to have much strength to hold the thick plate main body 7 of the pressing member 3 at right angles to the temporary steel pipe support 12.

[0019] 9, which shows the hypothetical temporary scaffolding assembly fitting 27 in use, the greatest problem is that the two points at which the worker works on this hypothetical temporary scaffolding assembly fitting 27—the nuts 22b of the fastening bolts and nuts 22 and the wedge bodies 18 that fasten the bifurcated connecting members 15 to the thick plate main body 7 of the presser member 3—are separated into the front and rear of the temporary steel pipe support 12. This problem inevitably reduces workability compared to when both work points are located on the same side of the temporary steel pipe support 12. However, the temporary scaffolding assembly fitting 1 of the present invention, which can directly use the wide base member 21 with the fastening bolts and nuts 22 of the previously described conventional pipe clamp 20, not only can it be used safely even with enormous loads, but it also offers excellent benefits in terms of cost and workability. [Industrial Applicability]

[0020] The temporary scaffolding assembly fittings of the present invention can be used when assembling temporary scaffolding by combining vertically oriented temporary steel pipe supports and erection members whose ends are fixed to the supports. [Explanation of symbols]

[0021] 1. Temporary scaffolding assembly hardware 2 Wide base member 2a Rising end 2b Lower free end 3 Presser member 4 Fastening bolts and nuts 4a Bolt 4b Nut 5 Back plate of wide base member 6a, 6b Side plate portion of wide base member 7 Thick plate body of the holding member 8 Cylindrical bearing member 9 U-shaped member 10,11 Support shaft 12 Temporary steel pipe supports 13 Wedge-driving recess 14 Horizontal steel pipe (construction member) 15 Bifurcated connecting member 16,17 Upper and lower extensions 16a, 17a Long holes for wedge insertion 16b Protrusion 18 cuneiform 19a, 19b Retaining pin 20 Conventional Pipe Clamp 21 Wide base member 21a Rising end 21b Lower free end 22 Fastening bolts and nuts 22a bolt 22b Nut 23a, 23b Side plate part 24,26 Support shaft 25 Arc-shaped holding member 25a Notch 27 Virtual temporary scaffolding assembly hardware 28 U-shaped member

Claims

[Claim 1] The wide base member is comprised of a wide base member, a presser member, and fastening bolts and nuts. The wide base member is L-shaped in side view, and is formed into a U-shaped cross section with side plate portions bent inward from both left and right sides of the L-shaped back plate portion. The presser member is comprised of a main body made of thick plate material, a cylindrical bearing member fixed at a right angle to one end of the main body made of thick plate, and a U-shaped member fixed to the other end of the main body made of thick plate. The presser member is supported between the side plate portions at the rising end of the wide base member by a support shaft that passes through the cylindrical bearing member so as to be able to open and close freely. a bolt of the fastening bolt nut is pivotally supported by a support shaft between the side plate portions of the lower free end of the wide base member so as to be freely swingable, and is supported so as to be freely fitted and disengaged within the U-shaped member of the holding member; a nut of the fastening bolt nut is configured to be able to thread onto the free end of the bolt and abut against the U-shaped member of the holding member; and a wedge-driving recess is formed in the thick plate body of the holding member along an imaginary radial line passing through the center of the temporary steel pipe support held between the thick plate body and the wide base member.

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