Jigs and construction methods

Abstract

The present invention aims to provide a jig that facilitates the sheet stretching process and a construction method that utilizes this jig. [Solution] The jig 1 of the present invention comprises a hook member 2 that can be hooked onto an inclined piece 11b3 of a sheet fastener 11 to which the end of the sheet S is fixed, an attachment member 3 that can be attached to and detached from the frame member 10 at a position below the sheet fastener 11, and a tensioning device 4 which has one end connected to the hook member 2 and the other end connected to the attachment member 3 and can pull in a direction that brings the hook member 2 and the attachment member 3 closer together. The hook member 2 has a stabilizer 5 that, when the hook member 2 is hooked onto the inclined piece 11b3 and comes into contact with the frame member 10, positions the hook member 2 in a position where the straight line connecting the part of the hook member 2 that comes into contact with the tip of the inclined piece 11b3 and the part of the hook member 2 to which the tensioning device 4 is connected is parallel to the part of the frame member 10 that faces the hook member 2.

Description

Technical Field

[0001] The present invention relates to a jig and a construction method using the jig. Background Art

[0002] A simple structure such as a plastic greenhouse, a glass greenhouse, or a simple warehouse includes a plurality of arched aggregates arranged side by side along the depth direction, and a sheet fixed to the aggregates via a plurality of sheet fastening members stretched between the aggregates.

[0003] The roof-side sheet in such a simple structure forms the roof of the simple structure by covering the upper part of the aggregates, with the left and right ends as viewed from the depth direction respectively fixed to respective sheet fastening members installed on the shoulder portions of the aggregates. Specifically, after one end of the roof-side sheet is fixed to one sheet fastening member, the other end of the roof-side sheet is pulled by hand to apply tension to the roof-side sheet while being fixed to the other sheet fastening member, so that the roof-side sheet is fixed to the aggregates in a tensioned state.

[0004] However, depending on the material and strength of the sheet, simply pulling the roof-side sheet manually cannot apply sufficient tension to the roof-side sheet, which may result in the sheet becoming slack. If the sheet is fixed to the aggregates in a slack state, there has been a problem that the sheet flutters due to wind or the like, rubs against and damages the aggregates, leading to deterioration of the sheet.

[0005] In response to this, Patent Document 1 discloses a jig that pulls the sheet fastening member obliquely downward to move the sheet fastening member downward along the aggregate, thereby applying tension to the roof-side sheet whose end is fixed to the sheet fastening member.

[0006] More specifically, the jig disclosed in Patent Document 1 comprises a rod-shaped base portion that spans between adjacent structural members in the depth direction below the sheet fastener, a rod-shaped handle portion that is rotatably connected to the base portion and positioned diagonally below the sheet fastener, and a connecting portion that connects the sheet fastener and the handle portion. In such a jig, when the handle portion is rotated toward the side away from the sheet fastener, a pulling force acts diagonally downward on the sheet fastener, causing the sheet fastener to move downward along the structural members. Thus, tension can be applied to the sheet on the roof side. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2002-176861 [Overview of the project] [Problems that the invention aims to solve]

[0008] Here, the sheet fastener has a bottom piece that abuts against the outside of the simple structure in the aggregate, and a pair of inclined pieces that rise up and inward from both ends of the bottom piece. With the sheet inserted into the groove formed between the inclined pieces, an elastic member is inserted into the groove from above the sheet, and the sheet is fixed to the sheet fastener by the elastic force of the elastic member. Therefore, the sheet is fixed to the front side of the sheet fastener (the side facing outwards from the simple structure).

[0009] Therefore, in the jig described in Patent Document 1, it was necessary to connect the upper end of the connecting part to the back side of the sheet fastener (the side facing the inside of the simple structure) so as not to damage the sheet fixed to the front side of the sheet fastener. Consequently, the jig described in Patent Document 1 is installed inside the simple structure.

[0010] However, when the jig is installed inside the temporary structure, the worker cannot see the sheet on the roof side from the outside of the structure when operating the handle. As a result, they cannot check if the sheet is slack while applying tension to it, forcing the worker to perform a cumbersome task to extend the sheet.

[0011] Therefore, the present invention aims to provide a jig that facilitates the sheet stretching process and a construction method that utilizes the jig. [Means for solving the problem]

[0012] The present invention, for achieving the above objective, provides a jig for applying tension to the sheet of a simple structure comprising: a plurality of arch-shaped or mountain-shaped structural members arranged in a line along the depth direction; a pair of sheet fasteners arranged on both sides of the top of the structural members and spanning across the structural members along the depth direction; and a sheet that forms a roof, with one end fixed to one sheet fastener and the other end fixed to the other sheet fastener, wherein the sheet fasteners have contact pieces that abut against each structural member and inclined pieces that slope upward from the lower end of the contact pieces, and the jig is hookable onto the inclined pieces. The device comprises a hook member, a mounting member that can be attached to and detached from the frame at a position below the sheet fastener, and a tensioning device, one end of which is connected to the hook member and the other end of which is connected to the mounting member, allowing the hook member and the mounting member to be pulled in a direction that brings them closer together. The hook member is characterized by having a stabilizer that, when the hook member is hooked onto the inclined piece and comes into contact with the frame, positions the hook member in a position where the straight line connecting the part of the hook member that contacts the tip of the inclined piece and the part of the hook member to which the tensioning device is connected is parallel to the part of the frame facing the hook member. With this configuration, since the hook member can be hooked onto the inclined piece of the sheet fastener, the jig can be installed on the outside of the simple structure. Therefore, the worker can operate the tensioning device while checking whether the sheet is slack from the outside of the simple structure, making the sheet tensioning work easier. Furthermore, when the stabilizer is brought into contact with the structural member while the hook member is hooked onto the inclined piece, the hook member is positioned such that the straight line connecting the part that contacts the tip of the inclined piece and the part to which the tensioning device is connected is parallel to the part of the structural member opposite to the hook member. Therefore, since the hook member is stably supported by the stabilizer so as not to tilt relative to the structural member, the hook member can move parallel to the structural member. Thus, even if the load of the tensioning device acts at an angle, the hook member can move parallel to the structural member, and the sheet fastener can be pulled down along the structural member. As a result, the sheet fastener can be moved downward relative to the structural member without placing an excessive load on the sheet fastener. In summary, by using the jig of the present invention, even if the hook member is hooked onto the sheet fastener, the sheet can be stretched without slack without damaging the sheet fastener.

[0013] In the jig of the present invention, the hook member has a plate-shaped base and an inclined plate portion extending diagonally downward from the upper end of the base, and a workspace free of obstacles may be provided on the side of the base opposite the inclined plate portion, extending from the upper end to the lower end of the base in a range of at least 5 cm. With this configuration, even when the hook member is hooked onto the inclined piece, screws can be driven into the contact piece of the sheet fastener with a part of the screw driver positioned within the workspace on the side of the base opposite the inclined plate portion. Therefore, after lowering the sheet fastener along the frame, the work of fastening the contact piece of the sheet fastener to the frame with screws using a screw driver can be easily performed to prevent the sheet fastener from rising due to the tension of the sheet.

[0014] In the jig of the present invention, the hook member is made of metal and has a plate-shaped base and an inclined plate portion extending diagonally downward from the upper end of the base, and the width of the boundary between the base and the inclined plate portion and the width of the inclined plate portion may each be 10 cm or more. With this configuration, since the width of the boundary between the base and the inclined plate portion, which is the part of the hook member that contacts the inclined piece, and the width of the inclined plate portion are 10 cm or more, it is possible to avoid the concentration of load from the hook member on a part of the inclined piece compared to the case where the width of the part of the hook member that contacts the inclined piece is less than 10 cm, and thus it is possible to suppress excessive load on the inclined piece.

[0015] Furthermore, in the jig of the present invention, the tensioning device may include a rope member, one end of which is connected to one of the hook member or mounting member, and a winding device, which is connected to the other end of the hook member or mounting member and capable of winding up the rope member by a ratchet mechanism. With this configuration, the tension of the rope member can be amplified by operating the winding device to wind up the rope member while maintaining the tension of the rope member. Therefore, the tensioning device can exert a large force while reducing the force required to operate the winding device in a single operation. Consequently, the burden on the worker when applying tension to the sheet can be greatly reduced, and a large tension can be applied to the sheet regardless of the material or strength of the sheet.

[0016] Furthermore, in the jig of the present invention, the rope member may be a belt, and the winding device may be a ratchet buckle capable of winding the belt by a ratchet mechanism. With this configuration, the tension of the belt can be amplified by operating the ratchet buckle to wind the belt while maintaining the belt tension, so the tensioning device can exert a large force while reducing the force required to operate the ratchet buckle in one operation. Therefore, the burden on the worker when applying tension to the sheet can be greatly reduced, and a large tension can be applied to the sheet regardless of the material or strength of the sheet. Moreover, with this configuration, the tensioning device is a lashing belt, and the weight of the tensioning device can be reduced, so the overall weight of the jig is also reduced. Therefore, the jig becomes easier for workers to handle even when working in unstable places. Furthermore, the size of the jig can be adjusted by adjusting the length of the belt. Therefore, the size of the jig can be appropriately adjusted according to the size of the installation space, improving the versatility of the jig.

[0017] Furthermore, the present invention relates to a construction method for a simple structure comprising a plurality of arch-shaped or mountain-shaped structural members arranged in a line along the depth direction, a pair of sheet fasteners arranged on both sides of the top of the structural members and stretched across the structural members along the depth direction, and a sheet that forms a roof with one end fixed to one sheet fastener and the other end fixed to the other sheet fastener, wherein the sheet fasteners each have a contact piece that abuts against the structural members and an inclined piece that slopes upward from the lower end of the contact piece, and the construction method relates to a construction method for applying tension to a sheet of a simple structure using a jig, wherein the jig comprises a hook member that can be hooked onto the inclined piece, an attachment member that can be attached to and detached from the structural members at a position below the sheet fasteners, and a member with one end connected to the hook member and the other end connected to the attachment member The device is equipped with a tensioning device that can pull the hook member and the mounting member toward each other. The hook member has a stabilizer that, when the hook member is hooked onto the inclined piece and comes into contact with the structural member, positions the hook member in a position where the straight line connecting the part of the hook member that comes into contact with the tip of the inclined piece and the part of the hook member to which the tensioning device is connected is parallel to the part of the structural member opposite to the hook member. The device is characterized by comprising the steps of hooking the hook member onto the inclined piece of the sheet fastener, attaching the mounting member to the structural member at a position below the sheet fastener, and moving the sheet fastener downward along the structural member by pulling the hook member and the mounting member toward each other using the tensioning device while bringing the stabilizer into contact with the structural member. With this configuration, since the hook member can be hooked onto the inclined piece of the sheet fastener, the jig can be installed on the outside of the greenhouse. Therefore, the worker can operate the tensioning device of the jig while checking from the outside of the greenhouse whether the sheet on the roof side is sagging, thus making the sheet tensioning work easier. Furthermore, when the stabilizer is brought into contact with the aggregate while the hook member is hooked onto the inclined piece, the hook member is positioned such that the straight line connecting the part that contacts the tip of the inclined piece and the part to which the tensioning device is connected is parallel to the part of the aggregate opposite the hook member. Therefore, since the hook member is stably supported by the stabilizer so as not to tilt relative to the aggregate, the hook member can move parallel to the aggregate.Accordingly, even if the load of the tension device acts obliquely, the hook member can move parallel to the aggregate, and the sheet stopper can be pulled down along the aggregate. Therefore, the sheet stopper can be moved downward relative to the aggregate without applying an unreasonable load to the sheet stopper. As described above, by using the jig of the present invention, the sheet can be stretched without slack without damaging the sheet stopper even when the hook member is hooked on the sheet stopper. [[Effect of the Invention]]

[0018] The jig and construction method of the present invention can facilitate the sheet stretching work. [[Brief Description of Drawings]]

[0019] [Figure 1] It is a front view of a plastic greenhouse as a simple structure in which only a roof-side sheet is stretched on an aggregate, viewed from the front side, showing a state where the jig according to the first embodiment is installed on a sheet stopper. [Figure 2] It is a partially enlarged front view of a plastic greenhouse as a simple structure, showing a partial enlargement of FIG. 1. [Figure 3] It is a side view of FIG. 2 viewed from the side of the plastic greenhouse. [Figure 4] It is an enlarged perspective view of a portion where the jig according to the first embodiment is hooked on a sheet stopper of a plastic greenhouse. [Figure 5] It is a side view showing the step of screwing a sheet stopper to an aggregate with a screw driving machine in the construction method using the jig according to the first embodiment. [Figure 6] It is a front view of the vicinity of a valley portion of a plastic greenhouse as a connected-row simple structure in which only a roof-side sheet is stretched on an aggregate, viewed from the front side, showing a state where the jig according to the second embodiment is installed on a sheet stopper. [Figure 7] It is an enlarged front view showing a part of FIG. 6. [Figure 8] It is an enlarged perspective view of FIG. 6 viewed from above. [Figure 9] It is a rear view of the jig according to the second embodiment. [MODE FOR CARRYING OUT THE INVENTION]

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

[0021] As shown in Fig. 1, a plastic greenhouse H as a simple structure includes a plurality of mountain-shaped aggregates arranged side by side along the depth direction, a pair of sheet stopping members arranged on both sides with the top of the aggregates interposed therebetween and stretched between the aggregates along the depth direction, and a sheet S having one end fixed to one sheet stopping member and the other end fixed to the other sheet stopping member to form a roof.

[0022] A jig 1 used for stretching the sheet S is used as follows. As shown in Fig. 1, the sheet S forming the roof is fixed to the pair of sheet stopping members 11, 11 fixed to the aggregate 10. Then, one sheet stopping member 11 is firmly fixed to the aggregate 10, and the temporarily fixed other sheet stopping member is pulled downward using the jig 1. As a result, the other side of the sheet S is pulled downward together with the other sheet stopping member, so tension is applied to the sheet S, and the sheet S is fixed to the aggregate 10 without slack.

[0023] As shown in Fig. 2, the jig 1 according to the first embodiment of the present invention includes a hook member that can be hooked on the sheet stopping member, a mounting member detachable from the aggregate at a position below the sheet stopping member, and a tensioning device having one end connected to the hook member and the other end connected to the mounting member and capable of pulling the hook member and the mounting member in a direction to bring them closer to each other. When the hook member is hooked on the sheet stopping member and the hook member and the mounting member are pulled together by the tensioning device, the mounting member is fixed to the aggregate, while the sheet stopping member is temporarily fixed to the aggregate and allowed to move downward relative to the aggregate. Therefore, the sheet stopping member is pulled downward to apply tension to the sheet S.

[0024] The following describes in detail the various parts of the greenhouse H and the jig 1. As shown in Figure 1, the frame 10 of the greenhouse H is configured in a mountain shape, having a pair of left and right support columns 10a, 10a that stand vertically from the ground, and a mountain-shaped roof portion 10b that connects the upper ends of the support columns 10a, 10a. The frame 10 may be made of a single member, or the support columns 10a and the roof portion 10b may be made of separate parts, and the frame 10 may be formed by attaching each end of the roof portion 10b to the upper ends of the support columns 10a, 10a. In this embodiment, the frame 10 is mountain-shaped, but the roof portion 10b may be arc-shaped and the frame 10 may be arch-shaped.

[0025] Furthermore, sheet fasteners 11 extending in the depth direction are installed on the outside of the shoulder portions that form the boundary between the support column portions 10a and the roof portion 10b on both the left and right sides in Figure 2, with the top of the frame material 10 in between. However, the sheet fasteners 11 may also be installed on parts other than the shoulder portions of the frame material 10. The sheet fasteners 11 consist of a pair of upper and lower sheet fixing frames 11a, 11b, each having a groove with a narrow opening width and a pair of flat contact pieces 11a1, 11b1 extending in the depth direction and a pair of inclined pieces 11a2, 11a3, 11b2, 11b3 that incline inward from the upper and lower ends of the contact pieces 11a1, 11b1, respectively, and a flat connecting piece 11c that connects the lower inclined piece 11a3 of the upper sheet fixing frame 11a and the upper inclined piece 11b2 of the lower sheet fixing frame 11b. The sheet fastener 11 is fixed to each of the structural members 10 via the fixing bracket 12, with the contact pieces 11a1 and 11b1 in contact with each structural member 10.

[0026] Although not described in detail here, the fixing bracket 12, as shown in Figure 2, comprises a holding piece 12a that holds the upper sheet fixing frame 11a and the structural member 10 of the sheet fastening material 11, and a wedge 12b that is inserted into a hole formed at the tip of the holding piece 12a. With the structural member 10 and the inclined pieces 11a2 and 11a3 of the upper sheet fixing frame 11a of the sheet fastening material 11 held by the holding piece 12a, the wedge 12b is driven into the hole formed at the tip of the holding piece 12a. As a result, the structural member 10 and the upper sheet fixing frame 11a are clamped between the holding piece 12a and the wedge 12b, and the sheet fastening material 11 is fixed to the structural member 10.

[0027] Furthermore, each end of the roof-side sheet S is inserted into the groove of the upper sheet fixing frame 11a of each sheet fixing member 11, and a corrugated spring material 13 is inserted into the groove of the upper sheet fixing frame 11a from above, thereby fixing the ends of the sheet S to the sheet fixing member 11 by the elastic force of the spring material 13. However, the method of fixing the roof-side sheet S to the upper sheet fixing frame 11a of the sheet fixing member 11 is not particularly limited. In this embodiment, a rigid sheet such as polyester film or fluoropolymer film is used for the roof-side sheet S, but a flexible sheet such as polyvinyl chloride film or polyolefin film such as PET film may also be used. In addition, although not shown, after the roof-side sheet S is stretched, the lower sheet fixing frame 11b of each sheet fixing member 11 is used to fix the upper end of the side sheet (not shown) that forms the side of the greenhouse H using a spring member. As described above, with the sheet fastening material 11 of this embodiment, the roof-side sheet S and the side-side sheet can be fixed to the upper sheet fixing frame 11a and the lower sheet fixing frame 11b, respectively, so that only the roof-side sheet S or only the side-side sheet can be replaced. Therefore, even if the types of roof-side sheet S and side-side sheet are different and the replacement frequency of the sheets differs, the sheet replacement work becomes easier. However, the sheet fastening material 11 may have only one sheet fixing frame, which is the part to which the sheet S can be fixed. In that case, the roof-side sheet S can be fixed within the sheet fixing frame, and then the side-side sheet can be overlapped and fixed on top of the roof-side sheet S.

[0028] Next, the jig 1 of the first embodiment will be described in detail. As mentioned above, the jig 1, as shown in Figures 2, 3, and 4, includes a hook member 2 that can be hooked onto the lower inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastening material 11, a mounting member 3 that can be attached and detached below the position where the sheet fastening material 11 is attached to the frame material 10, and a tensioning device 4 which has one end connected to the hook member 2 and the other end connected to the mounting member 3 and can be pulled in a direction that brings the hook member 2 and the mounting member 3 closer together.

[0029] As shown in Figures 2, 3, and 4, the hook member 2 is made of metal and comprises a hook body 20 having a plate-shaped base 20a and an inclined plate portion 20b extending diagonally downward from the upper end of the base 20a, and a rod-shaped handle portion 21 whose upper end is connected to the lower end of the base 20a.

[0030] As shown in Figures 3 and 4, the base portion 20a is formed in a T-shape, comprising a rectangular main plate portion 20a1 with a long width and a square plate-shaped retaining piece 20a2 extending downward from the center of the lower end of the main plate portion 20a1. The shape of the base portion 20a described above is merely an example and is not particularly limited. For example, the overall shape of the base portion 20a may be rectangular.

[0031] Furthermore, the inclined plate portion 20b has the same width as the main plate portion 20a1 of the base portion 20a, and extends diagonally downward to the left in Figure 2 from the upper end of the main plate portion 20a1. In this embodiment, the widths of the main plate portion 20a1 of the base portion 20a and the inclined plate portion 20b are both set to 10 cm or more, but they may be less than 10 cm. Also, the widths of the main plate portion 20a1 of the base portion 20a and the inclined plate portion 20b may be different. Moreover, as shown in Figure 2, the angle between the main plate portion 20a1 of the base portion 20a and the inclined plate portion 20b is approximately equal to the angle between the contact piece 11b1 and the inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastening material 11. Therefore, when the hook body 20 is hooked onto the inclined piece 11b3 of the lower sheet fixing frame 11b, the base portion 20a naturally becomes approximately parallel to the contact piece 11b1. Furthermore, although the hook body 20 is formed by bending a single metal plate, the hook body 20 may also be formed by welding or otherwise connecting an inclined plate portion 20b to the upper end of the base portion 20a.

[0032] The handle portion 21 comprises a rectangular pipe-shaped rod portion 21a extending parallel to the short direction (up and down direction in Figure 3) of the main plate portion 20a1 of the base portion 20a, with its upper end welded to the back side of the retaining piece 20a2 of the base portion 20a, which is the side opposite the inclined plate portion, and a connecting portion 21b provided at the lower end of the rod portion 21a and connectable to the tensioning device 4 described later. The connecting portion 21b has a flat plate-shaped projection piece 21b1 welded near the lower end of the left side of the rod portion 21a facing the structural member 10 in Figure 2 and protruding from the lower end of the rod portion 21a, and a vertically elongated ring 21b3 attached to a hole 21b2 formed at the lower end of the projection piece 21b1. The cross-sectional shape of the rod portion 21a is not particularly limited and may, for example, have a circular cross-section. Furthermore, the method of connecting the rod portion 21a and the hook body is not limited to welding; for example, the hook body 20 and the handle portion 21 may be connected by bolt fastening.

[0033] Furthermore, near the upper end of the left side of the handle portion 21a facing the structural member 10 in Figure 2, a stabilizer 5 is provided that contacts the structural member 10 when the hook member 2 is hooked onto the inclined piece 11b3 of the sheet fastening material 11. More specifically, as shown in Figure 2, the stabilizer 5 is rectangular and welded directly below the retaining piece 20a2 on the left side of the rod portion 21a in the handle portion 21. The height of the stabilizer 5 in the left-right direction in Figure 2 is set so that when the stabilizer 5 is in contact with the structural member 10, the base 20a of the hook member 2 and the surface of the rod portion 21a facing the structural member are parallel to and opposite the structural member 10. In other words, when the stabilizer 5 is brought into contact with the structural member 10 while the hook body 20 is hooked onto the inclined piece 11b3 of the sheet fastening material 11, the hook member 2 will be in a position (hereinafter referred to as the "parallel position") in which the straight line connecting the part of the hook member 2 that contacts the tip of the inclined piece 11b3 (the boundary between the base 20a and the inclined plate part 20b) and the part of the hook member 2 to which the tensioning device 4 described later is connected (the lower end of the connecting part 21b) is parallel to the support column part 10a of the structural member 10 that is opposite to the hook member 2.

[0034] Therefore, when the stabilizer 5 is brought into contact with the support portion 10a of the structural member 10 with the hook body 20 hooked onto the inclined piece 11b3, the hook member 2 is guided by the stabilizer 5 when moving the hook member 2 downward, allowing the hook member 2 to move downward without wobbling relative to the structural member 10. Here, "parallel" includes not only the case where the base 20a and the rod portion 21a of the hook member 2 facing the structural member are perfectly parallel to the structural member 10, but also the case where the base 20a and the rod portion 21a facing the structural member are slightly inclined relative to the structural member 10. Furthermore, the shape of the stabilizer 5 is not particularly limited, and for example, it may be a flat plate-shaped member protruding from the rod portion 21a toward the structural member 10. Furthermore, the stabilizer 5 may be provided anywhere on the hook member 2 that faces the structural member 10. For example, the stabilizer 5 may be provided near the lower end of the rod portion 21a or on the retaining piece 20a2 of the hook body 20. In addition, the stabilizer 5 may be provided on the rod portion 21a or the retaining piece 20a2 of the hook body 20 by methods other than welding.

[0035] Next, as shown in Figures 2 and 3, the mounting member 3 of this embodiment has a clamp portion 3a that holds the frame material 10 and can be attached to and detached from the frame material 10, and a ring-shaped connecting portion 3b provided on the clamp portion 3a. When the jig 1 is used, as shown in Figures 2 and 3, the clamp portion 3a is attached to the frame material 10 with the connecting portion 3b protruding from the frame material 10 towards the outdoor side of the greenhouse H (right side in Figure 2). However, the structure of the mounting member 3 is not particularly limited as long as it can be attached to any point on the frame material 10 with sufficient strength to not move even when pulled by the tensioning device 4 while attached to the frame material 10.

[0036] Furthermore, as shown in Figures 2 and 3, the tensioning device 4 of this embodiment includes a chain 40 as a rope member having a first hook 40a at one end, and a winding device 41 capable of winding up the chain 40. The winding device 41 is a lever hoist comprising a case 41a housing a gear-shaped load sheave (not shown) around which the chain 40 is wound, a reduction gear (not shown), and a ratchet mechanism (not shown), a second hook 41b provided at the upper end of the case 41a, and a lever 41c rotatably mounted on the case 41a and transmitting power to the load sheave via the reduction gear by rotational operation. In addition, the tensioning device 4 can transmit the power of the lever 41c via the ratchet mechanism to rotate the load sheave only in the direction that brings the first hook 40a and the second hook 41b closer together, and can also allow the load sheave to rotate freely by disconnecting the connection between the load sheave and the lever 41c.

[0037] Then, the second hook 41b of the winding device 41, which is one end of the tensioning device 4, is hooked onto the ring 21b3 of the connecting part 21b, connecting one end of the tensioning device 4 to the lower end of the hook member 2, and the first hook 40a provided on one end of the chain 40 of the winding device 41, which is the other end of the tensioning device 4, is hooked onto the ring-shaped connecting part 3b of the mounting member 3, connecting the other end of the tensioning device 4 to the mounting member 3. In this state, when the lever 41c is operated back and forth multiple times to rotate the load sheave and wind up the chain 40, the hook member 2 and the mounting member 3 are pulled in a direction toward each other. At this time, the tensioning device 4 is positioned parallel to the structural member 10 by the stabilizer 5, and the downward movement of the hook member 2 is guided by the stabilizer 5 so as to follow the structural member 10. Therefore, when the lower end of the tensioning device 4 is fixed to the structural member 10 via the mounting member 3 and the upper end of the tensioning device 4 is connected via the ring 21b3 to the protruding piece 21b1 provided on the structural member side surface of the rod portion 21a of the hook member 2, the tensioning device 4 is positioned together with the hook member 2 substantially parallel to the structural member 10. Thus, the line of action of the load of the tensioning device 4 becomes parallel to the structural member 10.

[0038] Furthermore, since the winding device 41 of the tensioning device 4 in this embodiment winds the chain 40 using a ratchet mechanism, even when the lever 41c is operated back and forth, the load sheave only rotates in the direction of winding the chain 40. Therefore, the tensioning device 4 can maintain the tension of the chain 40, and each time the lever 41c is operated back and forth, the load sheave rotates only in the winding direction, amplifying the tension of the chain 40. This allows for a large force to be exerted while reducing the force required for a single operation of the lever 41c. Note that by disconnecting the connection between the load sheave and the lever 41c, the load sheave can be allowed to rotate freely, thereby allowing the chain 40, which has been shortened by being wound up by the winding device 41, to be restored to its original length.

[0039] In this embodiment, the second hook 41b of the tensioning device 4 is hooked onto a ring 21b3 attached to a hole 21b2 in the protruding piece 21b1. However, the second hook 41b may also be directly hooked onto the hole 21b2 in the protruding piece 21b1. However, in this embodiment, the orientation of the second hook 41b of the tensioning device 4 and the rotation direction when the lever 41c is rotated are the same. Therefore, if the second hook 41b is directly hooked onto the hole 21b2 in the protruding piece 21b1 facing the aggregate 10, the lever 41c will be rotated toward the aggregate 10, making it difficult to operate the lever 41c. In contrast, the orientation of the hole in the ring 21b3 attached to the hole 21b2 of the protruding piece 21b1 is aligned with the depth direction of the greenhouse H. Therefore, when the second hook 41b is hooked into the hole in the ring 21b3 and the first hook 40a is hooked into the connection part 3b of the mounting member 3 which is positioned opposite the protruding piece 21b1 both vertically and horizontally, the rotation direction of the lever 41c is aligned with the depth direction of the greenhouse H, making it easier to operate the lever 41c.

[0040] Furthermore, the method of connecting the hook member 2 and the tensioning device 4 is not particularly limited, as long as the connection between the hook member 2 and the tensioning device 4 is not released when the tensioning device 4 exerts force. Also, in this embodiment, the mounting member 3 and the tensioning device 4 are connected by hooking the first hook 40a provided at one end of the chain 40 of the tensioning device 4 onto the connection part 3b of the mounting member 3, but instead of the first hook 40a, a clamp as a mounting member 3 that can be attached to and detached from the structural member 10 may be integrally connected to one end of the chain 40. Furthermore, the method of connecting the mounting member 3 and the tensioning device 4 is not particularly limited, as long as the connection between the mounting member 3 and the tensioning device 4 is not released when the tensioning device 4 exerts force.

[0041] Furthermore, although the pulling device 4 is a lever hoist in this embodiment, the pulling device 4 is not particularly limited as long as it can exert a pulling force in the direction that brings the hook member 2 and the mounting member 3 closer together. Also, the pulling device 4 may be electrically powered.

[0042] Next, a construction method for applying tension to the roof-side sheet S fixed between a pair of sheet fasteners 11, 11 using the jig 1 of the first embodiment will be described. First, in a greenhouse H where only the roof-side sheet S is stretched, loosen the wedges 12b of all the fixing fittings 12 that fix one sheet fastener 11 to the frame 10, to which one end of the roof-side sheet S is fixed. Then, the sheet fastener 11 is fixed to the frame 10 with a strength such that it does not move due to the tension of the roof-side sheet S or gravity, but it can move if a greater force is applied (hereinafter referred to as "temporarily fixed").

[0043] Next, the worker holds the rod portion 21a of the handle portion 21 of the hook member 2 and hooks the hook body 20 of the hook member 2 onto the lower inclined piece 11b3 that rises from the lower end of the contact piece 11b1 that abuts against the structural member 10 of the lower sheet fixing frame 11b of one of the sheet fixing members 11, as shown in Figures 2, 3, and 4. As a result, the hook member 2 hangs from the inclined piece 11b3 of the lower sheet fixing frame 11b with the handle portion 21 facing the structural member 10.

[0044] Here, the sheet fastening material 11 comprises an upper sheet fixing frame 11a and a lower sheet fixing frame 11b arranged side by side vertically. The roof-side sheet S is fixed to the upper sheet fixing frame 11a, and the hook member 2 is hooked onto the lower sheet fixing frame 11b. In other words, because the upper sheet fixing frame 11a to which the roof-side sheet S is fixed and the lower sheet fixing frame 11b to which the hook member 2 is hooked are separated, it is possible to prevent accidentally damaging the roof-side sheet S when hooking the hook member 2 onto the inclined piece 11b3 of the lower sheet fixing frame 11b. If the sheet fastening material 11 is composed of a single sheet fixing frame, the portion of the roof-side sheet S that protrudes from the lower inclined piece of the sheet fixing frame can be lifted up, and the hook member 2 can be hooked directly onto the inclined piece, thus avoiding damage to the sheet S.

[0045] Returning to the original position, the second hook 41b of the winding device 41 is hooked onto the ring 21b3 provided at the lower end of the rod portion 21a of the hook member 2, thereby connecting one end of the tensioning device 4 to the hook member 2. Subsequently, the mounting member 3 is connected to the portion of the support column 10a of the structural member 10 that is located below the tensioning device 4 connected to the hook member 2. Then, the other end of the tensioning device 4 is connected to the mounting member 3 by hooking the first hook 40a provided at one end of the chain 40 onto the ring-shaped connecting portion 3b of the mounting member 3 connected to the support column 10a of the structural member 10.

[0046] The sequence of steps for installing the jig 1 described above is merely an example, and the sequence of steps is not particularly limited. For example, one end of the tensioning device 4 may be connected to the hook member 2 in advance, and then the hook member 2 may be hooked onto the lower inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastener 11. Alternatively, the mounting member 3 may be connected to the support column portion 10a of the structural member 10 in advance.

[0047] Then, with the jig 1 in place, the stabilizer 5 is brought into contact with the support portion 10a of the structural member 10, and the lever 41c of the tensioning device 4 is moved back and forth multiple times to wind up the chain 40. As a result, the length of the chain 40 stretched between the hook member 2 and the mounting member 3 is shortened, and the tensioning device 4 exerts a pulling force in the direction that brings the hook member 2 and the mounting member 3 closer together. Here, the mounting member 3 is fixed to the structural member 10 so as not to move via the clamp portion 3a, while the sheet fastener 11 to which the hook member 2 is hooked is temporarily fixed by loosening the wedge 12b of the fixing fitting 12. Therefore, when the tensioning device 4 exerts a pulling force in the direction that brings the hook member 2 and the mounting member 3 closer together, the sheet fastener 11 to which the hook member 2 is hooked moves downward along the structural member 10. As a result, the roof-side sheet S, which has one end fixed to the sheet fastener 11, is also pulled downwards, and a large tension is applied to the roof-side sheet S, resulting in the sheet S being fixed without sagging.

[0048] Thus, in this embodiment, the hook member 2 can be hooked onto the lower inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastener 11 which is positioned outside the frame 10, allowing the jig 1 to be installed on the outside of the greenhouse H. Therefore, the worker can operate the lever 41c of the tensioning device 4 of the jig 1 while checking from the outside of the greenhouse H whether the sheet S on the roof side is sagging, thus facilitating the sheet tensioning work.

[0049] Furthermore, as mentioned above, the tensioning device 4 of this embodiment includes a chain 40 with one end connected to a hook member 2, and a winding device 41 connected to a mounting member 3 and capable of winding up the chain 40. The winding device 41 is equipped with a ratchet mechanism, which allows for the exertion of a large force while reducing the force required to operate the lever 41c in a single operation of the winding device 41. Therefore, the burden on the worker when applying tension to the roof-side sheet S can be greatly reduced, and a large tension can be applied to the roof-side sheet S regardless of the material or strength of the sheet S.

[0050] Here, if the hook member 2 could tilt freely relative to the frame member 10, the hook member 2 would be subjected to tensile load in a position tilted at an angle relative to the frame member 10, and depending on the strength of the sheet fastener 11, there is a risk that the sheet fastener 11 may deform. In particular, if the force exerted by the tensile device 4 is large, as in this embodiment, the load on the sheet fastener 11 will also be large.

[0051] In contrast, in this embodiment, the stabilizer 5 is brought into contact with the support portion 10a of the structural member 10, and the hook member 2 is hooked onto the lower inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastener 11, and the sheet fastener 11 is pulled downward by the force of the tensioning device 4. As described above, when the stabilizer 5 is brought into contact with the support portion 10a of the structural member 10 with the hook body 20 of the hook member 2 hooked onto the inclined piece 11b3 of the sheet fastener 11, the hook member 2 is positioned in a parallel position such that the straight line connecting the part of the hook member 2 that contacts the tip of the inclined piece 11b3 (the boundary between the base portion 20a and the inclined plate portion 20b) and the part of the hook member 2 to which the tensioning device 4 is connected (the lower end of the connecting portion 21b) is parallel to the support portion 10a of the structural member 10. Therefore, since the hook member 2 is stably supported by the stabilizer 5 so as not to tilt relative to the frame member 10, the hook member 2 can move parallel to the frame member 10. Thus, even if the load of the tensioning device 4 acts at an angle, the hook member 2 can move parallel to the frame member 10, and the sheet fastener 11 can be pulled down along the frame member 10. As a result, the sheet fastener 11 can be moved downward relative to the frame member 10 without placing an excessive load on the sheet fastener 11. In summary, by using the jig 1, even if the hook member 2 is hooked onto the sheet fastener 11, the sheet S can be stretched without slack without damaging the sheet fastener 11.

[0052] Furthermore, when one of the sheet fastening members 11 is pulled downward by the tensioning device 4, a large force acts on the portion of the sheet fastening member 11 where the hook member 2 of the inclined piece 11b3 of the lower sheet fixing frame 11b abuts. Here, as mentioned above, the width of the main plate portion 20a1 of the base portion 20a of the hook member 2 and the width of the inclined plate portion 20b are set to be 10 cm or more. Therefore, the width of the boundary portion between the base portion 20a and the inclined plate portion 20b, which is the portion of the hook member 2 that abuts the inclined piece 11b3, and the width of the inclined plate portion 20b are also 10 cm or more. Thus, if the width of the portion of the hook member 2 that contacts the inclined piece 11b3 is 10 cm or more, compared to the case where the width of the portion of the hook member 2 that contacts the inclined piece 11b3 is less than 10 cm, it is possible to avoid the concentration of load from the hook member 2 on a portion of the inclined piece 11b3 of the sheet fastener 11, thereby suppressing excessive load on the inclined piece 11b3 of the sheet fastener 11.

[0053] Furthermore, after using the jig 1 to lower one of the sheet fasteners 11 to a predetermined position, as shown in Figure 5, a screw is driven into the contact piece 11b1 that abuts against the structural member 10 on the lower sheet fixing frame 11b of the sheet fastener 11 using a screw gun 14 to fix the sheet fastener 11 to the structural member 10. This prevents the sheet fastener 11 from moving upward due to the increased tension of the roof-side sheet S after the jig 1 is removed.

[0054] In this embodiment, the hook member 2 has a vertical width of 5 cm or more of the main plate portion 20a1 of the base portion 20a of the hook body 20. The upper end of the rod portion 21a is welded to the back side of the retaining piece 20a2 of the base portion 20a, but nothing is provided on the back side of the main plate portion 20a1 of the base portion 20a. In other words, on the back side of the base portion 20a of the hook member 2, which is the side opposite the inclined plate portion, there is an unobstructed workspace of at least 5 cm from the upper end to the lower end of the base portion 20a.

[0055] As shown in Figure 5, the screw gun 14 comprises a horizontally oriented cylindrical housing 14a, an injection unit 14b that protrudes from the tip of the housing 14a (left end in Figure 5) and ejects screws, a magazine unit 14c connected to the lower tip of the housing 14a and containing screws to be supplied to the injection unit 14b, and a grip unit 14d located below the housing 14a and on the base end side of the magazine unit 14c (right side in Figure 5), which can be grasped by an operator. The grip unit 14d is provided with a trigger 14d1 that can be operated by the operator's fingertips, and when the trigger 14d1 is pulled, screws supplied from the magazine unit 14c are ejected from the injection unit 14b. Then, as shown in Figure 5, when using such a screw gun 14 to drive screws into the contact piece 11b1 of the lower sheet fixing frame 11b, the injection unit 14b abuts against the contact piece 11b1 in the groove of the lower sheet fixing frame 11b. As a result, a portion of the magazine section 14c, which is connected to the lower tip of the housing 14a, is positioned on the rear side of the base 20a of the hook body 20. As mentioned above, a workspace free of obstacles is provided on the rear side of the base 20a, extending at least 5 cm from the top to the bottom. Therefore, even when the hook member 2 is hooked onto the inclined piece 11b3 of the sheet fastening material 11, the screw driver 14 can be positioned within the workspace free of obstacles, allowing the driver to fasten screws to the contact piece 11b1 of the lower sheet fixing frame 11b. Thus, the driver can easily fasten the contact piece 11b1 of the lower sheet fixing frame 11b to the structural member 10 using the screw driver 14. The size of the workspace provided on the rear side of the base 20a can be appropriately determined depending on the size and shape of the screw driver 14 used for fastening screws. However, the vertical width of the main plate portion 20a1 of the base 20a, which constitutes the workspace, may be less than 5 cm. Furthermore, if the tension on the roof-side sheet S increases but the temporarily fixed sheet fastener 11 does not move upward, the step of screwing the sheet fastener 11 to the frame 10 may be omitted.

[0056] By performing the above operations at each contact point between one sheet fastener 11 and the structural member 10, one end of the roof-side sheet S is pulled downward evenly, and a large tension is applied to the portion of the roof-side sheet S from the top of the structural member 10 to one end. The order in which the contact points between one sheet fastener 11 and the structural member 10 are lowered is not particularly limited. Jigs 1 may be installed at some or all of the contact points between one sheet fastener 11 and the structural member 10 to lower multiple contact points between one sheet fastener 11 and the structural member 10 at once.

[0057] Finally, the sheet fasteners 11 are fixed to the frame members 10 by re-driving the wedges 12b of each fixing bracket 12 that had been loosened. Alternatively, the wedges 12b may be re-inserted each time the contact point between the sheet fastener 11 and the frame members 10 is lowered.

[0058] Furthermore, the other sheet fastener 11 is also pulled down along the frame 10 using the same procedure as the first sheet fastener 11. As a result, the other end of the roof-side sheet S is pulled downward evenly, and a large tension is applied to the portion of the roof-side sheet S from the top of the frame 10 to the other end.

[0059] When the pair of sheet fasteners 11, 11 positioned on both the left and right sides of the frame 10 are pulled down by the jig 1, a large tension is applied to the entire roof-side sheet S, preventing the sheet S from sagging. Therefore, even if the roof-side sheet S is buffeted by the wind, flapping of the roof-side sheet S is prevented, thus preventing the roof-side sheet S from rubbing against the frame 10 and deteriorating. Consequently, the lifespan of the roof-side sheet S is extended.

[0060] In particular, since rigid sheets such as fluorine film are very expensive, when the roof sheet S is made of a rigid sheet, the benefit of extending the lifespan by applying a large tension to the roof sheet S using the jig 1 is especially significant. Furthermore, when a large tension is applied to the roof sheet S, wrinkles are eliminated from the roof of the greenhouse H, thus improving the aesthetic appearance of the greenhouse H.

[0061] In this example, all contact points of the sheet fastener 11 with the structural members 10 are pulled down by the jig 1. However, if sufficient tension can be applied to the sheet S on the roof side, only a portion of the contact points of each structural member 10 on the sheet fastener 11 may be lowered using the jig 1. Alternatively, only one of the pair of sheet fasteners 11, 11 positioned on both the left and right sides of the structural member 10 may be lowered using the jig 1.

[0062] As described above, the jig 1 of this embodiment applies tension to the sheet S of a vinyl greenhouse H, which is a simple structure comprising a plurality of arch-shaped or mountain-shaped structural members 10 arranged in a line along the depth direction, a pair of sheet fasteners 11, 11 arranged on both sides of the top of the structural members 10 and stretched between the structural members 10 along the depth direction, and a sheet S which forms a roof with one end fixed to one sheet fastener 11 and the other end fixed to the other sheet fastener 11, and the sheet fasteners 11 each having a contact piece 11b1 that abuts against the structural members 10 and an inclined piece 11b3 that slopes upward from the lower end of the contact piece 11b1. Furthermore, the jig 1 of this embodiment comprises a hook member 2 that can be hooked onto an inclined piece 11b3, an attachment member 3 that can be attached to and detached from the structural member 10 at a position below the sheet fastening material 11, and a tensioning device 4, one end of which is connected to the hook member 2 and the other end of which is connected to the attachment member 3, and which can be pulled in a direction that brings the hook member 2 and the attachment member 3 closer together. The hook member 2 has a stabilizer 5 that, when the hook member 2 is hooked onto the inclined piece 11b3 and comes into contact with the structural member 10, positions the hook member 2 in a posture such that the straight line connecting the part of the hook member 2 that comes into contact with the tip of the inclined piece 11b3 and the part of the hook member 2 to which the tensioning device 4 is connected is parallel to the part of the structural member 10 that faces the hook member 2.

[0063] With the jig 1 configured in this way, the hook member 2 can be hooked onto the lower inclined piece 11b3 of the sheet fastener 11 which is positioned outside the frame 10, so that the jig 1 can be installed on the outside of the greenhouse H. Therefore, the worker can operate the lever 41c of the tensioning device 4 of the jig 1 while checking from the outside of the greenhouse H whether the sheet S on the roof side is sagging, thus making the sheet tensioning work easier.

[0064] Furthermore, when the stabilizer 5 is brought into contact with the structural member 10 while the hook member 2 is hooked onto the inclined piece 11b3 of the sheet fastener 11, the hook member 2 is positioned such that the straight line connecting the part that contacts the tip of the inclined piece 11b3 and the part to which the tensioning device 4 is connected is parallel to the part of the structural member 10 that is opposite to the hook member 2. Therefore, the hook member 2 is stably supported by the stabilizer 5 so as not to tilt relative to the structural member 10, and the hook member 2 can move parallel to the structural member 10. Thus, even if the load of the tensioning device 4 acts at an angle, the hook member 2 can move parallel to the structural member 10, and the sheet fastener 11 can be pulled down along the structural member 10. Therefore, the sheet fastener 11 can be moved downward relative to the structural member 10 without putting an excessive load on the sheet fastener 11. In summary, by using the jig 1, even if the hook member 2 is hooked onto the sheet fastener 11, the sheet S can be stretched without slack without damaging the sheet fastener 11.

[0065] Furthermore, in the jig 1 of this embodiment, the hook member 2 has a plate-shaped base 20a and an inclined plate portion 20b extending diagonally downward from the upper end of the base 20a, and a workspace free of obstacles is provided on the side of the base 20a opposite the inclined plate portion, extending from the upper end to the lower end of the base 20a for at least 5 cm. With the jig 1 configured in this way, even when the hook member 2 is hooked onto the inclined piece 11b3 of the sheet fastener 11, it is possible to drive screws into the contact piece 11b1 of the sheet fastener 11 with a screw driver 14 while positioning a part of the screw driver 14 within the workspace on the side of the base 20a opposite the inclined plate portion. Therefore, after lowering the sheet fastener 11 along the frame 10 with the jig 1, it is easy to perform the work of screwing the contact piece 11b1 of the sheet fastener 11 to the frame 10 using the screw driver 14 in order to prevent the sheet fastener 11 from rising due to the tension of the sheet S on the roof side. However, the vertical width of the above-mentioned workspace may be less than 5 cm.

[0066] Furthermore, the hook member 2 in this embodiment is made of metal and has a plate-shaped base portion 20a and an inclined plate portion 20b that extends diagonally downward from the upper end of the base portion 20a, with the width of the boundary portion between the base portion 20a and the inclined plate portion 20b and the width of the inclined plate portion 20b each being 10 cm or more. In the jig 1 configured in this way, since the width of the boundary portion between the base portion 20a and the inclined plate portion 20b, which is the part of the hook member 2 that contacts the inclined piece 11b3, and the width of the inclined plate portion 20b are 10 cm or more, it is possible to avoid the concentration of load from the hook member 2 on a part of the inclined piece 11b3 of the sheet fastener 11 compared to the case where the width of the part of the hook member 2 that contacts the inclined piece 11b3 is less than 10 cm, and thus it is possible to suppress excessive load on the inclined piece 11b3 of the sheet fastener 11. However, the width of the boundary between the base portion 20a and the inclined plate portion 20b, and the width of the inclined plate portion 20b, may each be less than 10 cm. Also, the shape of the hook member 2 is not particularly limited as long as it can be hooked onto the inclined piece 11b3 of the sheet fastening material 11. In this embodiment, the material of the hook member 2 is not particularly limited as long as it does not break when the hook member 2 is pulled by the tensioning device 4 while hooked onto the inclined piece 11b3 of the sheet fastening material 11.

[0067] Furthermore, in the jig 1 of this embodiment, the tensioning device 4 includes a chain 40 as a rope member with one end connected to the hook member 2, and a winding device 41 connected to the mounting member 3 and capable of winding up the chain 40 by a ratchet mechanism. With the jig 1 configured in this way, the tension of the chain 40 can be amplified by operating the winding device 41 to wind up the chain 40 while maintaining the tension of the chain 40. Therefore, the tensioning device 4 can exert a large force while reducing the force required to operate the winding device 41 in a single operation. Consequently, the burden on the worker when applying tension to the roof-side sheet S can be greatly reduced, and a large tension can be applied to the roof-side sheet S regardless of the material or strength of the roof-side sheet S. In addition, in the tensioning device 4, one end of the chain 40 may be connected to the mounting member 3, and the winding device 41 may be connected to the mounting member 3. Furthermore, the tensioning device 4 is not particularly limited as long as it can exert a pulling force in the direction that brings the hook member 2 and the mounting member 3 closer together. The rope member is not limited to a chain 40, but may be, for example, a wire rope.

[0068] Furthermore, the construction method using the jig 1 of this embodiment includes the steps of: hooking the hook member 2 onto the inclined piece 11b3 of the sheet fastening material 11; attaching the mounting member 3 to the frame material 10 at a position below the sheet fastening material 11; and moving the sheet fastening material 11 downward along the frame material 10 by pulling the hook member 2 and the mounting member 3 in a direction that brings them closer together using the tensioning device 4 while the stabilizer 5 is in contact with the frame material 10.

[0069] With this construction method, the hook member 2 is hooked onto the lower inclined piece 11b3 of the sheet fastener 11 which is positioned outside the frame 10, so the jig 1 can be installed on the outside of the greenhouse H. Therefore, the worker can operate the tensioning device 4 of the jig 1 while checking from the outside of the greenhouse H whether the sheet S on the roof side is sagging, thus making the sheet tensioning work easier.

[0070] Furthermore, when the stabilizer 5 is brought into contact with the structural member 10 while the hook member 2 is hooked onto the inclined piece 11b3 of the sheet fastener 11, the hook member 2 is positioned such that the straight line connecting the part that contacts the tip of the inclined piece 11b3 and the part to which the tensioning device 4 is connected is parallel to the part of the structural member 10 that is opposite to the hook member 2. Therefore, the hook member 2 is stably supported by the stabilizer 5 so as not to tilt relative to the structural member 10, and the hook member 2 can move parallel to the structural member 10. Thus, even if the load of the tensioning device 4 acts at an angle, the hook member 2 can move parallel to the structural member 10, and the sheet fastener 11 can be pulled down along the structural member 10. Therefore, the sheet fastener 11 can be moved downward relative to the structural member 10 without putting an excessive load on the sheet fastener 11. In summary, by using the jig 1, even if the hook member 2 is hooked onto the sheet fastener 11, the sheet S can be stretched without slack without damaging the sheet fastener 11.

[0071] Next, we will describe the jig 1A of the second embodiment of the present invention shown in Figures 6 to 9. In the following description, common components are denoted by the same reference numerals and detailed descriptions are omitted. The jig 1A of the second embodiment is mainly used in a series of greenhouses H, where multiple greenhouses H are arranged horizontally when viewed from the depth direction, as shown in Figure 6, to apply tension to the roof sheet S by pulling the sheet fastener 11, which is installed between the top and shoulder portions of the frame material 10, toward the valley formed between adjacent greenhouses H, H.

[0072] More specifically, in the connected greenhouse H, as shown in Figure 6, the shoulder portions (the boundary between the support portion 10a and the roof portion 10b) of adjacent greenhouse H are arranged to intersect with a staggered appearance in the depth direction. In addition, sheet fasteners 11 extending in the depth direction are installed on the roof portion 10b between the top and shoulder portions of the frame 10, with the lower sheet fixing frame 11b positioned on the lower side (valley side). Although not shown, the sheet fasteners 11 are fixed to the roof portion 10b of the frame 10 via the aforementioned fixing brackets 12. Also, as shown in Figure 6, gutter frames 15 extending in the depth direction are installed in the valleys between adjacent greenhouse H, H. As shown in Figures 6, 7, and 8, the gutter frame 15 comprises a gutter section 15a having a flat bottom piece 15a1 positioned so that its surface is horizontal between the shoulders of the aggregate members 10, 10, and a pair of left and right side pieces 15a2, 15a2 that extend diagonally outward and upward from the left and right ends of the bottom piece 15a1 in the figure and are supported by the aggregate members 10, 10, and a pair of sheet fixing parts 15b, 15b provided at the ends of each side piece 15a2 of the gutter section 15a. As shown in Figure 7, the sheet fixing section 15b has a flat bottom plate portion 15b1 that is inclined at an angle approximately parallel to the side piece 15a2 of the gutter section 15a, a pair of side wall portions 15b2 and 15b3 that extend inward from the upper and lower ends of the bottom plate portion 15b1, a connecting plate portion 15b4 that connects the tip of the lower side wall portion 15b2 to the upper end of the side piece 15a2 of the gutter section 15a, and a receiving piece 15b5 that extends upward from the tip of the upper side wall portion 15b3. The sheet fixing section 15b also has a groove with a narrow opening width formed by the bottom plate portion 15b1 and the pair of side wall portions 15b2 and 15b3. The gutter frame 15 is firmly fixed to each of the structural members 10, 10 by metal fittings not shown in the figure. In this embodiment, the gutter frame 15 is manufactured so that the gutter section 15a and the sheet fixing sections 15b, 15b are integrally formed by extrusion molding or the like. However, the gutter section 15a and the sheet fixing sections 15b, 15 may be manufactured separately, and the sheet fixing sections 15b, 15b may be fixed to the end of the gutter section 15a with screws or the like to manufacture the gutter frame 15.

[0073] Furthermore, although not shown in the diagram, a closing sheet can be stretched between each sheet fastener 11 installed between the top and shoulder portions of the structural member 10 and each sheet fixing portion 15b of the gutter frame 15 to close the gap between the sheet fastener 11 and the gutter frame 15. Specifically, the upper and lower ends of the closing sheet are inserted into the grooves of the lower sheet fixing frame 11b of the sheet fastener 11 and the grooves of the sheet fixing portion 15b of the gutter frame 15, respectively. A corrugated spring material is then inserted into the grooves of the lower sheet fixing frame 11b and the sheet fixing portion 15b from above the closing sheet, thereby fixing the upper and lower ends of the closing sheet to the lower sheet fixing frame 11b and the sheet fixing portion 15b, respectively, by the elastic force of the spring material. In this way, the closing sheet (not shown) is stretched between the sheet fastener 11 and the gutter frame 15. Then, water that adheres to the roof-side sheet S or the closing sheet due to rain, etc., is collected in the gutter frame 15 by flowing down the roof-side sheet S and the closing sheet. Furthermore, since the gap between the sheet fastening material 11 and each sheet fixing portion 15b of the gutter frame 15 is not very large, the width from the top to the bottom of the closing sheet is also short. Therefore, if the worker pulls the closing sheet by hand and fixes it to the lower sheet fixing frame 11b of the sheet fastening material 11 and the sheet fixing portion 15b of the gutter frame 15, sufficient tension can be applied to the closing sheet so that it does not flap in the wind.

[0074] Alternatively, instead of a sealing sheet that closes the gap between the sheet fastener 11 and the gutter frame 15, a ventilation device that can open and close the gap between the sheet fastener 11 and the gutter frame 15 may be provided. Specifically, the ventilation device comprises a ventilation sheet, one end of which is fixed to the lower sheet fixing frame 11b of the sheet fastener 11, and a winding shaft connected to the other end of the ventilation sheet. By rolling the winding shaft on the structural members 10, the winding shaft can wind up and unwind the ventilation sheet.

[0075] Next, the jig 1A of the second embodiment will be described in detail. As shown in Figures 7, 8, and 9, the jig 1A of the second embodiment includes a hook member 6 that can be hooked onto the inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastening material 11, a mounting member 7 that can be attached to and detached from the structural member 10 via the gutter frame 15 at a position lower than the sheet fastening material 11, and a tensioning device 8 which has one end connected to the hook member 6 and the other end connected to the mounting member 7 and can be pulled in a direction that brings the hook member 6 and the mounting member 7 closer together.

[0076] The following describes in detail each part of the jig 1A of the second embodiment. The hook member 6 is made of metal and, as shown in Figures 7, 8, and 9, comprises a base 6a formed in a T shape with a rectangular main plate portion 6a1 having a long width and a square plate-shaped retaining piece 6a2 extending downward from the center of the lower end of the main plate portion 6a1, and an inclined plate portion 6b extending diagonally downward from the upper end of the main plate portion 6a1 of the base 6a. The shape of the base 6a is not particularly limited. For example, the overall shape of the base 6a may be rectangular. The width of the inclined plate portion 6b is the same as that of the main plate portion 6a1 of the base 6a. The widths of the main plate portion 6a1 and the inclined plate portion 6b of the base 6a are set to be 10 cm or more, but they may be less than 10 cm. The widths of the main plate portion 6a1 and the inclined plate portion 6b of the base 6a may be different. Furthermore, although the hook member 6 is formed by bending a single metal plate, the hook member 6 may also be formed by welding an inclined plate portion 6b to the upper end of the base portion 6a.

[0077] Furthermore, as shown in Figure 7, the hook member 6 has a stabilizer 9 that contacts the structural member 10 when the hook member 6 is hooked onto the inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastening material 11. More specifically, the stabilizer 9 is rectangular and is welded to the front side (left side in Figure 7) of the retaining piece 6a2 at the base 6a, which is the side of the inclined plate portion 6b. The height of the stabilizer 9 is set so that when the stabilizer 9 contacts the structural member 10, the surface of the base 6a of the hook member 6 that faces the structural member is parallel to and opposite the structural member 10. In other words, when the stabilizer 9 is brought into contact with the structural member 10 with the hook member 6 hooked onto the inclined piece 11b3 of the sheet fastening material 11, the hook member 6 assumes a parallel position where the straight line connecting the part of the hook member 6 that contacts the tip of the inclined piece 11b3 (the boundary between the base 6a and the inclined plate portion 6b) and the part of the hook member 6 to which the tensioning device 8 described later is connected (the lower end of the holding piece 6a2 of the base 6a) is parallel to the part of the structural member 10 that faces the hook member 6. Therefore, as shown in Figure 7, when the stabilizer 9 is brought into contact with the roof portion 10b of the structural member 10 with the hook member 6 hooked onto the inclined piece 11b3, the hook member 6 is guided by the stabilizer 9 when moving the hook member 6 downwards, allowing the hook member 6 to move downwards without wobbling relative to the structural member 10. In this context, "parallel" includes not only the case where the surface of the base 6a of the hook member 6 facing the structural member is perfectly parallel to the structural member 10, but also the case where the surface of the base 6a of the hook member 6 facing the structural member is slightly inclined with respect to the structural member 10. Furthermore, the shape of the stabilizer 9 is not particularly limited and may be, for example, a flat plate-shaped member protruding from the retaining piece 6a2 toward the structural member 10. Also, the stabilizer 9 may be provided anywhere on the hook member 6 that faces the structural member 10, for example, on the part of the main plate portion 6a1 that faces the structural member 10. Furthermore, the stabilizer 5 may be provided on the base 6a by methods other than welding.

[0078] The mounting member 7 is made of metal and, as shown in Figures 7, 8, and 9, has a hook shape with a rectangular plate-shaped base 7a that is long in width and an inclined plate portion 7b that extends diagonally upward from the lower end of the base 7a. Furthermore, the base 7a of the mounting member 7 is supported from below by a receiving piece 15b5 of the sheet fixing portion 15b when the mounting member 7 is hooked onto the upper side wall portion 15b3 of the sheet fixing portion 15b. Therefore, the inclination of the upper end of the mounting member 7 toward the frame material 10 is restricted by the receiving piece 15b5, so that the mounting member 7 can be maintained in the position where it is hooked onto the upper side wall portion 15b3.

[0079] Furthermore, as mentioned above, the gutter frame 15 is fixed to the structural member 10 by fittings not shown in the figure. Therefore, when the mounting member 7 is hooked onto the upper side wall portion 15b3 of the sheet fixing portion 15b, the mounting member 7 is attached to the structural member 10 via the gutter frame 15. The shape of the base portion 7a is not particularly limited and may be, for example, T-shaped. The width of the base portion 7a and the inclined plate portion 7b are the same and are set to be 10 cm or more, but they may be less than 10 cm. The widths of the base portion 7a and the inclined plate portion 7b may be different. The structure of the mounting member 7 is not particularly limited as long as it can be detachably attached to the structural member 10. For example, the mounting member 7 may be a clamp that can be detachably attached to the structural member 10. In this embodiment, the mounting member 7 is hooked onto the upper side wall portion 15b3 of the sheet fixing portion 15b of the gutter frame 15. However, for example, a frame material having an inclined portion to which the mounting member 7 can be hooked may be installed between the sheet fastener 11 of the structural member 10 and the gutter frame 15, and the mounting member 7 may be hooked onto the inclined portion of that frame material.

[0080] As shown in Figure 9, the tensioning device 8 is a known lashing belt comprising a belt 81 as a rope member with one end connected to a mounting member 7, and a ratchet buckle 80 as a winding device that is welded to the back side of the retaining piece 6a2 of the base 6a of the hook member 6, which is the side opposite the inclined plate portion, and which can wind up the belt 81 by a ratchet mechanism. Specifically, the ratchet buckle 80 comprises a winding shaft 80a capable of winding up the belt 81, a pair of gears 80b, 80b provided at both ends of the winding shaft 80a, a lever 80c that can rotate the gears 80b, 80b only in the winding direction of the winding shaft 80a by a ratchet mechanism, and a stopper (not shown) that prevents the reverse rotation of the gears 80b, 80b. The belt 81 is wound around the winding shaft 80a of the ratchet buckle 80, and one end is connected to the upper end of the mounting member 7. Furthermore, the ratchet buckle 80 allows the gear 80b to rotate freely by releasing the stopper, thereby disconnecting the gear 80b from the lever 80c.

[0081] Then, with the hook member 6 hooked onto the inclined piece 11b3 of the sheet fastening material 11 and the hook-shaped mounting member 7 hooked onto the upper side wall portion 15b3 of the sheet fixing portion 15b of the gutter frame 15, the belt 81 is wound up by repeatedly moving the lever 80c back and forth, causing the hook member 6 and the mounting member 7 to be pulled towards each other. At this time, the tensioning device 8 is positioned so that the hook member 6 is parallel to the structural member 0 by the stabilizer 9, and the downward movement of the hook member 6 is guided by the stabilizer 9 so that it follows the structural member 10. Therefore, the tensioning device 8 is positioned approximately parallel to the structural member 10 together with the hook member 6. Thus, the line of action of the load of the tensioning device 4 is parallel to the structural member 10.

[0082] Furthermore, in this embodiment, the ratchet buckle 80, which serves as the winding device for the tensioning device 8, winds the belt 81 using a ratchet mechanism. Therefore, even when the lever 80c is operated back and forth, the gear 80b rotates only in the direction of winding the belt 81. As a result, the tensioning device 8 can maintain the tension of the belt 81, and each time the lever 80c is operated back and forth, the gear 80b rotates only in the winding direction, amplifying the tension of the belt 81. This allows for a large force to be exerted while reducing the force required for a single operation of the lever 80c. By releasing the stopper and disconnecting the gear 80b from the lever 80c, the gear 80b can be allowed to rotate freely, thereby allowing the belt 81, which has been shortened by being wound onto the ratchet buckle 80, to be restored to its original length. The tensioning device 8 is not particularly limited as long as it exerts a pulling force in the direction that brings the hook member 6 and the mounting member 7 closer together. The tensioning device 8 may also be electrically powered.

[0083] Furthermore, as shown in Figure 9, one end of the belt 81 is passed through a through hole 7a1 located in the center of the upper end of the base 7a of the mounting member 7, and the two ends of the belt 81 are bundled together with a buckle 82. The overlapping portion of the belt 81 is then secured with tape 83 to prevent the buckle 82 from coming off, thereby connecting one end of the belt 81 to the mounting member 7. In this way, the belt 81 is wrapped around the winding shaft 80a of the ratchet buckle 80 in a folded state because the two ends are bundled together with the buckle 82, thus improving the tensile strength of the belt 81. However, if the tensile strength of the belt 81 is sufficient, the belt 81 may be wrapped around the winding shaft 80a without being folded. Furthermore, as shown in Figure 9, a rectangular plate-shaped reinforcing plate 84 is fixed to the upper end of the back side of the base 7a of the mounting member 7 by bolts (not shown) with the portion of the belt 81 that contacts the base 7a sandwiched between the base 7a and the reinforcing plate 84. The reinforcing plate 84 can reinforce the strength of the portion of the base 7a where the insertion hole 7a1 is provided. In addition, by sandwiching the belt 81 between the reinforcing plate 84 and the base 7a, the load on the portion of the belt 81 that contacts the edge of the insertion hole 7a1 of the base 7a can be reduced when the mounting member 7 is pulled upward by the tensioning device 8. However, if the strength of the base 7a and the belt 81 is sufficient, the reinforcing plate 84 may be omitted. Note that the above-described method of connecting the belt 81 to the mounting member 7 is just one example and is not particularly limited as long as the belt 81 does not come off the mounting member 7 when the tensioning device 8 exerts a tensile force.

[0084] Next, a construction method will be described for applying tension to the roof-side sheet S, one end of which is fixed to the upper sheet fixing frame 11a of the sheet fastener 11 provided between the top and shoulder portions of the structural members 10, in a multi-unit vinyl greenhouse H, using the jig 1A of the second embodiment.

[0085] First, in a multi-unit vinyl greenhouse H with only the roof sheet S extended, loosen the wedges 12b of all fixing brackets 12 that secure the sheet fastener 11 to the frame 10, and temporarily fix the sheet fastener 11 to the frame 10. Next, using the gutter frame 15 as a foothold, the worker hooks the hook member 6 of the jig 1A onto the lower inclined piece 11b3 of the lower sheet fixing frame 11b at the point where the sheet fastener 11 contacts the frame 10. At this time, by bringing the stabilizer 9 of the hook member 6 into contact with the frame 10, the hook member 6 is prevented from tilting toward the frame 10 due to gravity, and the hook member 6 is prevented from coming off the sheet fastener 11. In this example, the worker uses the gutter frame 15 as a foothold, but if the gutter frame 15 does not have sufficient strength to be used as a foothold, the work may be done on a stepladder.

[0086] Furthermore, the mounting member 7 is attached to the upper side wall portion 15b3 of the sheet fixing portion 15b of the gutter frame 15 by hooking the hook-shaped mounting member 7 of the jig 1A, thereby connecting the mounting member 7 to a position lower than the sheet fastener 11 of the structural member 10 via the gutter frame 15. In this way, the jig 1A is installed between the sheet fastener 11 and the gutter frame 15.

[0087] In this embodiment, the tensioning device 8 of the jig 1A is a lashing belt comprising a belt 81 with one end connected to the mounting member 7, and a ratchet buckle 80 connected to the hook member 6 as a winding device capable of winding up the belt 81 by a ratchet mechanism. Therefore, the weight of the tensioning device 8 is lighter compared to the case where the tensioning device 4 is a lever hoist equipped with a chain 40, as in the jig 1 of the first embodiment. Consequently, the overall weight of the jig 1A is also lighter, making it easier for workers to handle the jig 1A when working in unstable places such as the gutter frame 15 or a stepladder. Thus, if the tensioning device 8 is a lashing belt, the work of installing the jig 1A between the sheet fastener 11 and the gutter frame 15 becomes easier. In addition, the size of the jig 1A can be adjusted by adjusting the length of the belt 81 of the tensioning device 8. Therefore, since the size of the jig 1A can be adjusted appropriately according to the size of the installation space, the jig 1A can be installed even in narrow spaces such as between the sheet fastener 11 installed between the top and shoulder of the structural member 10 in the valley of the greenhouse H and the gutter frame 15 installed in the valley of the greenhouse H.

[0088] Then, with the jig 1A set up in this manner, the lever 80c of the ratchet buckle 80 is operated back and forth multiple times to wind the belt 81 onto the winding shaft 80a. As a result, the length of the belt 81 positioned between the hook member 6 and the mounting member 7 is shortened, and the tensioning device 8 exerts a pulling force in the direction that brings the hook member 6 and the mounting member 7 closer together. Here, the mounting member 7 is connected to the structural member 10 via a gutter frame 15 that is firmly fixed to the structural member 10, whereas the sheet fastener 11 to which the hook member 6 is hooked is only temporarily fixed to the structural member 10. Therefore, when the tensioning device 8 exerts a pulling force in the direction that brings the hook member 6 and the mounting member 7 closer together, the sheet fastener 11 to which the hook member 6 is hooked moves downward along the structural member 10. As a result, one end of the roof-side sheet S fixed to the sheet fastener 11 is also pulled downward, so a large tension is applied to the roof-side sheet S.

[0089] Thus, in this embodiment, the hook member 6 is hooked onto the lower inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastener 11 which is positioned outside the frame 10. As a result, the jig 1A can be installed on the outside of the greenhouse H. Therefore, the worker can operate the lever 80c of the tensioning device 8 of the jig 1A while checking from the outside of the greenhouse H whether the sheet S on the roof side is sagging, thus facilitating the sheet tensioning work.

[0090] Furthermore, as mentioned above, the tensioning device 8 of this embodiment includes a belt 81 as a rope member with one end connected to the mounting member 7, and a ratchet buckle 80 as a winding device connected to the hook member 6 and capable of winding up the belt 81 by a ratchet mechanism. This allows for the exertion of a large force while reducing the force required to operate the lever 80c of the ratchet buckle 80 in a single operation. Therefore, the burden on the worker when applying tension to the roof-side sheet S can be greatly reduced, and a large tension can be applied to the roof-side sheet S regardless of the material or strength of the sheet S.

[0091] Here, if the hook member 6 could tilt freely relative to the frame member 10, the hook member 2 would be subjected to tensile load in a position tilted at an angle relative to the frame member 10, and depending on the strength of the sheet fastener 11, there is a risk that the sheet fastener 11 may deform. In particular, if the force exerted by the tensile device 8 is large, as in this embodiment, the load on the sheet fastener 11 will also be large.

[0092] In contrast, in this embodiment, the stabilizer 9 is brought into contact with the roof portion 10b of the structural member 10, and the hook member 6 is hooked onto the lower inclined piece 11b3 of the lower sheet fixing frame 11b of the sheet fastener 11, and the sheet fastener 11 is pulled downward by the force of the tensioning device 8. As described above, when the stabilizer 9 is brought into contact with the roof portion 10b of the structural member 10 with the hook member 6 hooked onto the inclined piece 11b3 of the sheet fastener 11, the hook member 6 is positioned in a parallel position such that the straight line connecting the part of the hook member 6 that contacts the tip of the inclined piece 11b3 (the boundary between the base portion 6a and the inclined plate portion 6b) and the part of the hook member 6 to which the tensioning device 8 described later is connected (the lower end of the holding piece 6a2 of the base portion 6a) is parallel to the part of the structural member 10 that faces the hook member 6. Therefore, since the hook member 6 is stably supported by the stabilizer 9 so as not to tilt relative to the frame 10, the hook member 6 can move parallel to the frame 10. Thus, even if the load of the tensioning device 8 is applied at an angle, the hook member 6 can move parallel to the frame 10, and the sheet fastener 11 can be pulled down along the frame 10. As a result, the sheet fastener 11 can be moved downward relative to the frame 10 without placing an excessive load on the sheet fastener 11. Therefore, by using the jig 1A, even if the hook member 2 is hooked onto the sheet fastener 11, the sheet S can be stretched without slack without damaging the sheet fastener 11.

[0093] Furthermore, when the sheet fastening material 11 is pulled downward by the tensioning device 8, a large force acts on the portion of the sheet fastening material 11 where the hook member 6 of the inclined piece 11b3 of the lower sheet fixing frame 11b contacts. As mentioned above, the width of the main plate portion 6a1 of the base portion 6a and the width of the inclined plate portion 6b of the hook member 6 are set to be 10 cm or more. Therefore, the width of the boundary portion between the base portion 6a and the inclined plate portion 6b, which is the portion of the hook member 6 that contacts the inclined piece 11b3, and the width of the inclined plate portion 6b are also 10 cm or more. Thus, if the width of the portion of the hook member 6 that contacts the inclined piece 11b3 is 10 cm or more, compared to the case where the width of the portion of the hook member 6 that contacts the inclined piece 11b3 is less than 10 cm, it is possible to avoid the concentration of load from the hook member 6 on a portion of the inclined piece 11b3 of the sheet fastener 11, thereby suppressing excessive load on the inclined piece 11b3 of the sheet fastener 11.

[0094] Furthermore, in this embodiment, the mounting member 7 is formed in a hook shape with a base portion 7a and an inclined plate portion 7b, and the hook-shaped mounting member 7 is hooked onto the upper side wall portion 15b3 of the sheet fixing portion 15b of the gutter frame 15. Therefore, when the tensioning device 8 exerts force, a large force is also acted on the upper side wall portion 15b3 of the sheet fixing portion 15b. Similar to the hook member 6, the mounting member 7 is set so that the width of both the base portion 7a and the inclined plate portion 7b is 10 cm or more. Accordingly, the width of the boundary portion between the base portion 7a and the inclined plate portion 7b, which is the part that comes into contact with the upper side wall portion 15b3 of the mounting member 7, and the width of the inclined plate portion 7b are also 10 cm or more. Thus, if the width of the portion of the mounting member 7 that contacts the upper side wall portion 15b3 is 10 cm or more, compared to the case where the width of the portion of the mounting member 7 that contacts the upper side wall portion 15b3 is less than 10 cm, it is possible to avoid the concentration of load on a portion of the upper side wall portion 15b3 of the sheet fixing portion 15b on the gutter frame 15 from the mounting member 7, and thus it is possible to suppress excessive load on the upper side wall portion 15b3 of the sheet fixing portion 15b. However, if the strength of the sheet fixing portion 15b is insufficient even if the width of the portion of the mounting member 7 that contacts the upper side wall portion 15b3 is 10 cm or more, or if the gutter frame 15 is not provided with a sheet fixing portion 15b, the mounting member 7 may be made into a clamp that can be attached to and detached from the structural member 10, and the mounting member 7 may be directly attached to a position lower than the sheet fastener 11 on the structural member 10.

[0095] Next, although not shown in the diagram, similar to the construction method using jig 1 in the first embodiment, after lowering the sheet fastener 11 to a predetermined position using jig 1A, screws are driven into the contact piece 11b1 that abuts against the structural member 10 on the lower sheet fixing frame 11b of the sheet fastener 11 using a screw gun 14 to fix the sheet fastener 11 to the structural member 10. This prevents the sheet fastener 11 from moving upward due to the increased tension of the roof-side sheet S after the jig 1A is removed.

[0096] In this embodiment, the hook member 6 is configured such that the vertical width of the main plate portion 6a1 of the base portion 6a is 5 cm or more. The ratchet buckle 80 of the tensioning device 8 is welded to the back side of the retaining piece 6a2 of the base portion 6a, but nothing is provided on the back side of the main plate portion 6a1 of the base portion 6a. In other words, on the back side of the base portion 6a of the hook member 6, which is the side opposite the inclined plate portion, there is an unobstructed workspace of at least 5 cm from the upper end to the lower end of the base portion 6a. Therefore, even when the hook member 6 is hooked onto the inclined piece 11b3 of the sheet fastening material 11, it is possible to drive screws into the contact piece 11b1 of the lower sheet fixing frame 11b with a part of the screw driver 14 positioned within the unobstructed workspace. Thus, the worker can easily use the screw driver 14 to screw the contact piece 11b1 of the lower sheet fixing frame 11b to the frame material 10. The size of the workspace provided on the back side of the base 6a can be appropriately determined by the size of the screw gun 14 used for driving the screws. However, the vertical width of the main plate portion 6a1 of the base 6a that constitutes the workspace may be less than 5 cm. Also, if the sheet fastener 11 in its temporarily fixed state does not move upward even when the tension of the sheet S on the roof side increases, the step of screwing the sheet fastener 11 to the frame 10 may be omitted.

[0097] By performing the above operations at each contact point between the sheet fastener 11 and the structural member 10, one end of the roof-side sheet S is pulled downward evenly, and a large tension is applied to the portion of the roof-side sheet S from the top of the structural member 10 to one end. The order in which the contact points between the sheet fastener 11 and the structural member 10 are lowered is not particularly limited. Jigs 1A may be installed at some or all of the contact points between the sheet fastener 11 and the structural member 10 to lower multiple contact points between the sheet fastener 11 and the structural member 10 at once.

[0098] Finally, the sheet fasteners 11 are fixed to the frame members 10 by re-driving the wedges 12b of each fixing bracket 12 that had been loosened. Note that the wedges 12b may be re-inserted each time the contact point between the sheet fastener 11 and the frame members 10 is lowered.

[0099] Furthermore, the sheet fastener 11 (not shown), to which the other end of the roof-side sheet S is fixed, is also lowered along the frame 10 using the same procedure. This causes the other end of the roof-side sheet S to be pulled downward evenly, and a large tension is applied to the portion of the roof-side sheet S from the top of the frame 10 to the other end.

[0100] When the pair of sheet fasteners 11, 11 positioned on both the left and right sides of the frame 10 are lowered by the jig 1A, a large tension is applied to the entire roof-side sheet S, preventing it from sagging. Therefore, even if the roof-side sheet S is buffeted by the wind, flapping is prevented, thus preventing the roof-side sheet S from rubbing against the frame 10 and deteriorating. Consequently, the lifespan of the roof-side sheet S is extended.

[0101] In particular, since rigid sheets such as fluorine film are very expensive, when the roof sheet S is made of a rigid sheet, the benefit of extending the lifespan by applying a large tension to the roof sheet S using jig 1A is especially significant. Furthermore, when a large tension is applied to the roof sheet S, wrinkles are eliminated from the roof of the greenhouse H, thus improving the aesthetic appearance of the greenhouse H.

[0102] In this example, all contact points of the sheet fastener 11 with the structural members 10 are lowered using the jig 1A. However, if sufficient tension can be applied to the sheet S on the roof side, only a portion of the contact points of each structural member 10 on the sheet fastener 11 may be lowered using the jig 1A. Alternatively, only one of the pair of sheet fasteners 11, 11 positioned on both the left and right sides of the structural member 10 may be lowered using the jig 1A.

[0103] Furthermore, the jig 1A of the second embodiment can also be used in place of the jig 1 of the first embodiment to lower the sheet fastener 11, which is provided on the shoulder portion of the frame material 10, along the support portion 10a of the frame material 10.

[0104] As described above, the jig 1A of this embodiment applies tension to the sheet S of a vinyl greenhouse H, which is a simple structure comprising a plurality of arch-shaped or mountain-shaped structural members 10 arranged in a line along the depth direction, a pair of sheet fasteners 11, 11 arranged on both sides of the top of the structural members 10 and stretched between the structural members 10 along the depth direction, and a sheet S that forms a roof with one end fixed to one sheet fastener 11 and the other end fixed to the other sheet fastener 11, and the sheet fasteners 11 each having a contact piece 11b1 that abuts against the structural members 10 and an inclined piece 11b3 that slopes upward from the lower end of the contact piece 11b1. Furthermore, the jig 1A of this embodiment includes a hook member 6 that can be hooked onto the inclined piece 11b3, a mounting member 7 that can be attached to and detached from the frame material 10 at a position below the sheet fastening material 11, and a tensioning device 8 which has one end connected to the hook member 6 and the other end connected to the mounting member 7 and can pull in a direction that brings the hook member 6 and the mounting member 7 closer together. The hook member 6 has a stabilizer 9 that, when the hook member 6 is hooked onto the inclined piece 11b3 and comes into contact with the frame material 10, positions the hook member 2 in a position where the straight line connecting the part of the hook member 6 that comes into contact with the tip of the inclined piece 11b3 and the part of the hook member 6 to which the tensioning device 8 is connected is parallel to the part of the frame material 10 that faces the hook member 2.

[0105] With the jig 1A configured in this way, the hook member 6 is hooked onto the lower inclined piece 11b3 of the sheet fastener 11 which is positioned outside the frame 10, so the jig 1A can be installed on the outside of the greenhouse H. Therefore, the worker can operate the lever 80c of the tensioning device 8 of the jig 1A while checking from the outside of the greenhouse H whether the sheet S on the roof side is sagging, thus making the sheet tensioning work easier.

[0106] Furthermore, when the stabilizer 9 is brought into contact with the structural member 10 while the hook member 6 is hooked onto the inclined piece 11b3 of the sheet fastener 11, the hook member 6 is positioned such that the straight line connecting the part that contacts the tip of the inclined piece 11b3 and the part to which the tensioning device 8 is connected is parallel to the part of the structural member 10 that is opposite to the hook member 6. Therefore, the hook member 6 is stably supported by the stabilizer 9 so as not to tilt relative to the structural member 10, and the hook member 6 can move parallel to the structural member 10. Thus, even if the load of the tensioning device 8 acts at an angle, the hook member 6 can move parallel to the structural member 10, and the sheet fastener 11 can be pulled down along the structural member 10. Therefore, the sheet fastener 11 can be moved downward relative to the structural member 10 without putting an excessive load on the sheet fastener 11. As a result, by using the jig 1A, even if the hook member 6 is hooked onto the sheet fastener 11, the sheet S can be stretched without slack without damaging the sheet fastener 11.

[0107] Furthermore, in the jig 1A of this embodiment, the hook member 6 has a plate-shaped base 6a and an inclined plate portion 6b extending diagonally downward from the upper end of the base 6a, and a workspace free of obstacles is provided on the side of the base 6a opposite the inclined plate portion, extending from the upper end to the lower end of the base 6a for at least 5 cm. With the jig 1A configured in this way, even when the hook member 6 is hooked onto the inclined piece 11b3 of the sheet fastener 11, it is possible to drive screws into the contact piece 11b1 of the sheet fastener 11 with a screw driver 14 while positioning a part of the screw driver 14 within the workspace on the side of the base 6a opposite the inclined plate portion. Therefore, after lowering the sheet fastener 11 along the frame 10 with the jig 1A, it is easy to screw the contact piece 11b1 of the sheet fastener 11 to the frame 10 using the screw driver 14 to prevent the sheet fastener 11 from rising due to the tension of the sheet S on the roof side. However, the vertical width of the workspace may be less than 5 cm.

[0108] Furthermore, the hook member 6 in this embodiment is made of metal and has a plate-shaped base 6a and an inclined plate portion 6b that extends diagonally downward from the upper end of the base 6a, with the width of the boundary portion between the base 6a and the inclined plate portion 6b and the width of the inclined plate portion 6b each being 10 cm or more. In the jig 1A configured in this way, since the width of the boundary portion between the base 6a and the inclined plate portion 6b, which is the part of the hook member 6 that contacts the inclined piece 11b3, and the width of the inclined plate portion 6b are 10 cm or more, it is possible to avoid the concentration of load from the hook member 6 on a part of the inclined piece 11b3 of the sheet fastener 11 compared to the case where the width of the part of the hook member 6 that contacts the inclined piece 11b3 is less than 10 cm, and thus it is possible to suppress excessive load on the inclined piece 11b3 of the sheet fastener 11. However, the width of the boundary portion between the base 6a and the inclined plate portion 6b and the width of the inclined plate portion 6b may each be less than 10 cm. Furthermore, the shape of the hook member 6 is not particularly limited as long as it can be hooked onto the inclined piece 11b3 of the sheet fastening material 11. In this embodiment, the material of the hook member 6 is not particularly limited as long as it does not break when the hook member 2 is pulled by the tensioning device 4 while hooked onto the inclined piece 11b3 of the sheet fastening material 11.

[0109] Furthermore, in the jig 1A of this embodiment, the tensioning device 8 has a belt 81 with one end connected to a mounting member 7, and a ratchet buckle 80 connected to a hook member 6 as a winding device that can wind up the belt 81 by a ratchet mechanism. With the jig 1A configured in this way, the tension of the belt 81 can be amplified by operating the ratchet buckle 80 to wind up the belt 81 while maintaining the tension of the belt 81. Therefore, the tensioning device 8 can exert a large force while reducing the force required to operate the ratchet buckle 80 in a single operation. Consequently, the burden on the worker when applying tension to the roof-side sheet S can be greatly reduced, and a large tension can be applied to the roof-side sheet S regardless of the material or strength of the roof-side sheet S. In addition, since the tensioning device 8 is a lashing belt equipped with a belt 81 and a ratchet buckle 80 and is lightweight, the overall weight of the jig 1A is also reduced. Consequently, the jig 1A is easier for workers to handle even when working in unstable locations. Furthermore, the size of the jig 1A can be adjusted by adjusting the length of the belt 81. Therefore, the size of the jig 1A can be appropriately adjusted according to the size of the installation space, thus improving the versatility of the jig 1A. In addition, in the tensioning device 8, one end of the belt 81 may be connected to the hook member 6 and the ratchet buckle 80 may be connected to the mounting member 7. However, the structure of the tensioning device 8 is not particularly limited as long as it exerts a pulling force in the direction that brings the hook member 6 and the mounting member 7 closer together.

[0110] Furthermore, the construction method using the jig 1A of this embodiment includes the steps of hooking the hook member 6 onto the inclined piece 11b3 of the sheet fastening material 11, attaching the mounting member 7 to the frame material 10 at a position below the sheet fastening material 11, and moving the sheet fastening material 11 downward along the frame material 10 by pulling the hook member 6 and the mounting member 7 in a direction that brings them closer together using the tensioning device 8 while the stabilizer 9 is in contact with the frame material 10.

[0111] With this construction method, the hook member 6 is hooked onto the lower inclined piece 11b3 of the sheet fastener 11, which is positioned on the outside of the frame 10, so that the jig 1A can be installed on the outside of the greenhouse H. Therefore, the worker can operate the tensioning device 8 of the jig 1A while checking from the outside of the greenhouse H whether the sheet S on the roof side is sagging, thus making the sheet tensioning work easier.

[0112] Furthermore, when the stabilizer 9 is brought into contact with the structural member 10 while the hook member 6 is hooked onto the inclined piece 11b3 of the sheet fastener 11, the hook member 6 is positioned such that the straight line connecting the part that contacts the tip of the inclined piece 11b3 and the part to which the tensioning device 8 is connected is parallel to the part of the structural member 10 that is opposite to the hook member 6. Therefore, the hook member 6 is stably supported by the stabilizer 9 so as not to tilt relative to the structural member 10, and the hook member 6 can move parallel to the structural member 10. Thus, even if the load of the tensioning device 8 acts at an angle, the hook member 6 can move parallel to the structural member 10, and the sheet fastener 11 can be pulled down along the structural member 10. Therefore, the sheet fastener 11 can be moved downward relative to the structural member 10 without putting an excessive load on the sheet fastener 11. As a result, by using the jig 1A, even if the hook member 6 is hooked onto the sheet fastener 11, the sheet S can be stretched without slack without damaging the sheet fastener 11.

[0113] Furthermore, although a vinyl greenhouse H was described as an example of a simple structure in this embodiment, the simple structure may be a greenhouse or a simple warehouse, etc. If the simple structure is a warehouse, the sheet covering the roof side may be a sheet made of a light-blocking material or a heat-insulating material. Such sheets made of light-blocking materials or heat-insulating materials may be even less stretchable than rigid sheets made of polyester film, fluoropolymer film, etc. In the jigs 1,1A of this embodiment, the tensioning devices 4,8 are equipped with a winding device that winds up the chain 40 or belt 81 as a rope member with a ratchet structure, and since it is possible to exert a large force while reducing the force required to operate the winding device, sufficient tension can be applied even to sheets made of light-blocking materials or heat-insulating materials that are very difficult to stretch.

[0114] 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]

[0115] 1,1A...Jig, 2,6...Hook member, 3,7...Mounting member, 4,8...Tensioning device, 5,9...Stabilizer, 10...Frame material, 11...Sheet fastener, 11b1...Contact piece, 11b3...Inclined piece, 20a,6a...Base, 20b,6b...Inclined plate section, 40...Chain (rope member), 81...Belt (rope member), 41...Winding device, 80...Ratchet buckle (winding device), H...Greenhouse (simple structure), S...Sheet

Claims

1. A jig for applying tension to a sheet of a simple structure comprising: a plurality of arch-shaped or mountain-shaped structural members arranged in a line along the depth direction; a pair of sheet fasteners arranged on both sides of the top of the structural members and spanning between the structural members along the depth direction; and a sheet that forms a roof, with one end fixed to one sheet fastener and the other end fixed to the other sheet fastener, wherein the sheet fasteners each have a contact piece that abuts against the structural members and an inclined piece that slopes upward from the lower end of the contact piece, A hook member that can be hooked onto the inclined piece, A mounting member that can be attached to and detached from the frame at a position below the sheet fastening material, The device comprises a tensioning device having one end connected to the hook member and the other end connected to the mounting member, which can be pulled in a direction that brings the hook member and the mounting member closer together. The hook member has a stabilizer that, when the hook member is hooked onto the inclined piece and brought into contact with the aggregate, positions the hook member in a position such that the straight line connecting the portion of the hook member that contacts the tip of the inclined piece and the portion of the hook member to which the tensioning device is connected is parallel to the portion of the aggregate facing the hook member. A jig characterized by the following features.

2. The hook member has a plate-shaped base and an inclined plate portion extending diagonally downward from the upper end of the base. A workspace free of obstacles is provided on the side of the base that is not inclined, extending at least 5 cm from the upper end to the lower end of the base. The jig according to claim 1.

3. The hook member is made of metal and has a plate-shaped base and an inclined plate portion that extends diagonally downward from the upper end of the base. The width of the boundary between the base and the inclined plate and the width of the inclined plate are both 10 cm or more. The jig according to claim 1.

4. The tensioning device comprises a cable member, one end of which is connected to either the hook member or the mounting member, and a winding device, which is connected to the other end of the hook member or the mounting member and capable of winding up the cable member by a ratchet mechanism. The jig according to claim 1.

5. The aforementioned cable member is a belt, The winding device is a ratchet buckle capable of winding the belt by a ratchet mechanism. The jig according to feature 4.

6. A construction method for applying tension to a sheet of a simple structure using a jig, comprising: a plurality of arch-shaped or mountain-shaped structural members arranged in a line along the depth direction; a pair of sheet fasteners arranged on both sides of the top of the structural members and spanning between the structural members along the depth direction; and a sheet that forms a roof, with one end fixed to one sheet fastener and the other end fixed to the other sheet fastener, wherein the sheet fasteners each have a contact piece that abuts against the structural members and an inclined piece that slopes upward from the lower end of the contact piece, The aforementioned jig is A hook member that can be hooked onto the inclined piece, A mounting member that can be attached to and detached from the frame at a position below the sheet fastening material, The device comprises a tensioning device having one end connected to the hook member and the other end connected to the mounting member, which can be pulled in a direction that brings the hook member and the mounting member closer together. The hook member has a stabilizer that, when the hook member is hooked onto the inclined piece and comes into contact with the aggregate, positions the hook member in a position such that the straight line connecting the portion of the hook member that contacts the tip of the inclined piece and the portion of the hook member to which the tensioning device is connected is parallel to the portion of the aggregate facing the hook member. The process of hooking the hook member onto the inclined piece of the sheet fastening material, The steps include: attaching the mounting member to the frame at a position below the sheet fastening member; The process includes the step of bringing the stabilizer into contact with the structural member, and using the tensioning device to pull the hook member and the mounting member in a direction that brings them closer together, thereby moving the sheet fastening member downward along the structural member. A construction method characterized by the following features.

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