SHEET STRETCHER

Abstract: A sheet setting-up device (7) is provided with a base portion (7a). The base portion (7a) has: a hole (17) for slidably receiving a bulged portion (5) formed at an outermost edge portion of a sheet (2); a slit (18) communicating with the hole (17) and capable of receiving an edge portion (11) of the sheet (2) connectingly provided to the bulged portion (5); hole (19) capable of slidably receiving another bulged portion (5) formed at an outermost edge portion of another sheet (2); and a slit (20) communicating with the hole (19) and capable of receiving an edge portion (11) of another sheet (2) connectingly provided to another bulged portion (5).

Description: This invention relates to sheet stretchers for stretching a sheet for a construction used on the site of constructing, taking down, or repairing a building or the like or at the painting site, or a sheet for the prevention of paint scattering, or a sheet for advertisement displays used in outdoor advertisements. Besides, this invention relates to sheet assemblies which are used on a construction site, or on a painting site, of constructing, taking down, or repairing a building, or at an outdoor advertisement. For example, on a construction site, a scaffolding is set up around a building and a sheet is stretched around the scaffolding. Conventionally, in such sheet stretching, unit sheets or a sheet and a scaffolding are connected by rope or wire being passed sequentially through eyelets provided in the respective sheets. The workability of stretching sheets with the rope passed through the eyelets as described above is extremely low, and much time is spent. The connection by the rope is not so satisfactory because unit sheets with eyelets must be prepared and unit sheets themselves cannot help being expensive . These problems arise similarly in sheets which are put up at a painting site or sheets for advertisement display used at the outdoor advertisement and the like. In view of the above, it is an object of the present invention to provide an sheet stretcher which is capable of stretching a sheet very easily. According to the present invention, there is provided a sheet stretcher comprising: a base; a first hole provided on the base for slidably receiving an expanded portion formed at an edge of a sheet; a first slit provided on the base and continuous to the first hole and through which the edge of the sheet continuous to the expanded portion is insertable; a second hole provided on the base for slidably receiving either an expanded portion of an attachment adjuster having an attachment plate continuous to the expanded portion or a further expanded portion formed at an edge of a further sheet; and a second slit provided on the base and formed continuous to the second hole and through which either the attachment plate of the attachment adjuster or the edge of the further sheet formed continuous to the further expanded portion is insertable, the second hole being formed opposite to the first hole and the second slit being formed opposite to the first slit; characterised by: a plurality of slots provided on the base in a line substantially parallel to the longitudinal axis of the base and into each of which a string-like member for connecting the sheet stretcher with a frame is insertable, the slots being disposed between the first and the second holes. The sheet stretcher according to the present invention may be made of any one of wood, metal and a synthetic resin. It is preferably made of hard plastics or aluminum in view of mechanical strength and lightness, and more preferably made of aluminum. The sheet stretcher in the present invention may have a cavity therein as far as hardness permits in order to lighten it. While the length of the sheet stretcher in the present invention may correspond to the length of a long side or a shorter side of the edge of the sheet to which the equipment is applied, it may instead be sufficiently shorter than the respective lengths of the long and shorter sides of the applied sheet. A plurality of such shorter stretchers may be provided to each of adjacent edges of sheets to stretch the sheets. Especially, when the length of the edge of the sheet is more than several meters, the use of a required number of sheets whose length is one meter at most to connect adjacent edges of both the sheets facilitates sheet stretching. The sheet in the present invention may be a general one obtained by extrusion of a material such as a nylon sheet or a vinyl sheet, or it may be a cloth sheet or a nonwoven fabric sheet made of natural fibers, chemical fibers or a combination of these fibers. Besides, the sheet in the present invention is not required to be completely non-cellular, and It may be a mesh-like sheet which is called a net. The expanded portion of the sheet may an expansion integral with an edge of a sheet itself. Alternatively, it may be one formed by rolling up an edge of a sheet itself. Alternatively, it may be one formed by inserting a rope into a loop made at an edge of a sheet by folding and seaming. The expanded portion of the sheet is not required to be formed on the overall edge of the sheet. It is only required to be formed at least at adjacent edges of sheets in connection with the sheet stretcher used. Alternatively, the sheets are not required to have corresponding continuous expanded portions through the whole length of the adjacent edges of the sheets, but they may have at least discrete expanded portions along the adjacent edges of the sheets. The sectional shape of the expanded portions may be, circular, triangular, rectangular or more polygonal. The first and the second holes in the present invention may be a through hole which opens to the outside at each end. Alternatively, they may be a hole of which at least one end is open to the outside to receive the corresponding expanded portion, and therefore, it may be a hole closed at the other end. The sectional shape of the first and the second holes may be circular, triangular, rectangular or more polygonal in connection with the shape of the expanded portion of the sheet or in the connection with the shape of the sheet removal preventer surrounding the edge of the sheet or in connection with the shape of the expanded portion of the attachment adjuster. The widths of the first and the second slits are required to be such that the expanded portion of the sheet is not removed through the slit. If the slit is too narrow, the freedom of the sheet will be lost, sheet stretching will be difficult, or the edges of the sheet may be damaged. In order to prevent damage to the edges of the sheet, that portion of the sheet stretcher which defines the slits is required to be smooth. The sheet assembly which is assembled by using the sheet stretcher in the present invention is not limited to applied to the building construction, but, for example, it may be applied on the painting site or to the advertisement display. In order to securely connect a long sheet stretcher to the frame without tilt and lowering its mechanical strength, a plurality of slots are preferably disposed discretely in the stretcher along its long side. As the string-like member inserted into the present slots, rope, wire, or a belt with a buckle may be exemplified, but other string-like members may be usable, of course. In the present invention, the expanded portion of the sheet is inserted and received in the first hole in the sheet stretcher, the expanded portion of a further sheet is inserted and received in the second hole in the sheet stretcher. This work is made further for still further sheet stretchers and other sheets prepared to thereby obtain an sheet assembly. When each sheet stretcher is connected to a frame for stretching a sheet through connecting means, the sheet assembly is held firmly to the frame, and as a result, the center of the sheet assembly is prevented from being swelled in wind and so on. For example, when the sheet assembly is successively heightened in accordance with the increasing height of a high-rise building under construction by stretching sheets sequentially upwards in accordance with the progress of construction of the building, the string-like member inserted Into the slots is connected to the frame and the uppermost sheet stretcher during the construction is attached temporarily to the frame. After this temporary attachment, when another sheet is put up above the sheet stretched so far, the temporary attachment is released and a new sheet is applied to the sheet stretcher. The present invention will be described hereinafter in more detail with reference to exemplary embodiments and the accompanying drawings, in which: Fig. 1 is a front view of a sheet assembly described for reference which is assembled by using a sheet stretcher; Fig. 2 is a sectional view taken along the line II - II shown in Fig. 1; Fig. 3 is a sectional view taken along the line III - III shown in Figs. 1 and 4; Fig. 4 is a front view of another sheet assembly described for reference which is assembled by using another sheet stretcher; Fig. 5 is a front view of the essential part of a sheet assembly which is assembled by using an attachment adjuster; Fig. 6 is a sectional view taken along the line VI - VI shown in Fig. 5; Fig. 7 is a front view of a sheet assembly which is assembled by using a sheet stretcher of a preferred embodiment of the present invention; Fig. 8 is a sectional view taken along the line X III - X III shown in Fig. 7; Fig. 9 illustrates in sectional view connection to a frame by the use of the sheet stretcher of the preferred embodiment shown in Fig. 8; Fig. 10 is a front view of another sheet usable with embodiments of the present invention; Fig. 11 is a front view of another sheet usable with embodiments of the present invention; Fig. 12 is a sectional view of a sheet stretcher in which a sheet removal preventer is used; Fig. 13 is a sectional view of another sheet stretcher in which a sheet removal preventer is used; Fig. 14 is a detailed explanatory view of the sheet removal preventer shown in Figs. 12 and 13; and Fig. 15 is a sectional view of another sheet stretcher described for reference. Referring to Figs. 1-3, a sheet assembly 1 which is put up so as to surround a scaffolding as the frame at the construction site comprises many unit sheets 2. In the respective sheets 2 their upper and lower edges are folded and seamed respectively at a position 3, and a rope 4 is inserted into the thus formed respective edge loops to form expanded portions 5. In the sheet assembly 1, first sheet stretchers 6 extending horizontally are applied between an upper edge of the uppermost sheet 2 and a horizontal member of a scaffolding (not shown) concerned as well as between a lower edge of the lowermost sheet 2 and a horizontal member of the scaffolding concerned. A second sheet stretcher 7 extending horizontally is applied between a lower edge of an upper sheet 2 and an upper edge of a lower sheet 2. The sheet stretcher 6 comprises a semicylindrical portion 8 and an attachment plate 9 formed integral with the semicylindrical portion 8. The semicylindrical portion 8 has through its overall length a first through hole 10 which slidably receives the expanded portion 5 formed at the edge of the sheet 2 as well as a first slit 12 communicating with the through hole 10 and through which an edge portion 11 formed continuous to the expanded portion 5 of the sheet 2 is insertable. An attachment plate 9 formed integral with the opposite side of the semicylindrical portion 8 from the slit 12 has slots 13 at a plurality of positions. Wire or rope 14 wound around the horizontal member of the scaffolding is inserted into the slots 13, so that the sheet stretcher 6 is attached to the horizontal member of the scaffolding. The sheet stretcher 7 comprises two semicylindrical portions 15 and 16 formed integral with each other. The semicylindrical portion 15 has through its overall length a first through hole 17 which slidably receives the expanded portion 5 formed at the lower edge of the upper sheet 2 as well as a first slit 18 formed continuous to the through hole 17 and through which the edge portion 11 formed continuous to the expanded portion 5 of the upper sheet 2 is insertable. The semicylindrical portion 16 has through its overall length a second through hole 19 formed on the opposite side of the stretcher 7 from the slit 18 to slidably receive the expanded portion 5 formed at an upper edge of the lower sheet 2 as well as a second slit 20 formed continuous to the through hole 19 and opposite to the slit 18, and through which the edge 11 continuous to the expanded portion 5 of the lower sheet 2 is insertable. The sheet stretcher 7 connects the upper and lower sheets 2 at their edges such that the through holes 17 and 19 receive the expanded portions 5 of the upper and lower sheets 2, respectively. In the sheet assembly 1 a sheet 2 with eyelets 21 in its right and left edges is used, the adjacent right and left sheets 2 are connected to each other at their edges with wire or rope 22 inserted into the adjacent eyelets 21. The left and right edges of the leftmost and rightmost sheets 2 are connected to vertical members of the scaffolding through the rope 22. The sheet assembly 1 thus composed is framed around the scaffolding in the construction site as described above, thereby preventing the building materials from falling downwards on a road during construction due to carelessness. In the sheet stretchers 6 and 7 applied to the sheet assembly 1, many sheets 2 can be put up very easily in a short time to assemble the sheet assembly 1 just by inserting the expanded portions 5 of the sheets 2 into the through holes 10, 17, and 19 successively through from the ends of the stretchers. While adjacent right and left sheets 2 with eyelets 21 in their right and left edges are connected by the rope 22 to each other and the leftmost and rightmost sheets 2 are connected to the respective associated vertical members of the scaffolding in the sheet assembly 1, rectangular sheets 2 which have cutouts at their four corners as well as expanded portions at their right and left edges as shown in Fig. 4 may be prepared, every adjacent right and left sheets are connected by sheet stretchers 7, and the leftmost and rightmost sheets 2 are connected to the respective associated vertical members of the scaffolding by the sheet stretcher 6 and rope 14 to compose a sheet assembly 31. Such construction needs neither eyelets of the sheets 2 nor work for connecting the sheets 2 to each other by rope or wire. In this case, either an additional expanded portion 32 is required to be formed on the sheet 2 or the above-mentioned sheet stretcher 7 with through holes 17 and 19 shut at one end is required to be used, in order to prevent the sheet stretcher 7 that connects adjacent right and left sheets from falling. In the sheet assembly 31 the separate sheet stretchers 6 and 7 are used in each sheet 2. Such use of the separate respective sheet stretchers 6 and 7 can improve workability. While the sheets 2 are attached to the horizontal and vertical members of the scaffolding through the sheet stretchers 6 with the slots 13 in the sheet assemblies 1 and 31, two attachment adjusters 44 each comprising an expanded portion 41 and an attachment plate 43 continuous to the expanded portion 41 and having a slot 42 may be prepared, and the respective expanded portions 41 of the attachment adjusters 44 may be inserted into the through holes 17 in the sheet stretchers 7 from one end of the sheet stretchers 7 to make the adapter plates 43 extend through the slits 18 so as to make the expanded portions 41 of the attachment adjusters 44 slidably received in the through holes 17. The uppermost, lowermost, rightmost and leftmost sheets 2 may be attached to the scaffolding by inserting rope 14 into the slot 42 and winding the rope 14 around the horizontal or the vertical member of the scaffolding. The use of such attachment adjuster 44 is preferable as the case may be because the position of attachment of the sheets to the scaffolding through the rope 14 can be adjusted since the adjuster is slidable relative to the sheet stretcher 7, that is, in the direction A, as shown in Figs. 5 and 6. Besides, a slit 45 and a cavity 46 communicating with the slit 45 may be formed in the expanded portion 41 of the attachment adjuster 44 in order to lighten the adjuster. While two attachment adjusters 44 are used for the connection of the sheet to the scaffolding in the present embodiment, one or more than three adjusters may instead be used for connection to the scaffolding. As mentioned above, the uppermost part of each of the sheet assemblies 1 and 31 is connected to the scaffolding horizontal member through the sheet stretcher 6 in the embodiments shown in Figs. 1 and 4. In such sheet assemblies 1 and 31, when a higher sheet assembly is to be assembled by putting up another sheet 2 above the assembly, the sheet stretcher 6 must be removed and a new sheet stretcher 7 must be used instead. Therefore, a sheet stretcher 7 according to the present invention, such as is shown in Figs. 7 and 8, may be used. In the sheet stretcher 7 shown in Figs. 7 and 8, a plurality of slots 125 through which the string-like member connecting the sheet stretcher 7 to the frame is insertable are discretely formed between the through holes 17 and 19 in and along the longitudinally extending sheet stretcher 7 as well as a plurality of circular holes 126 are formed in correspondence to the eyelets 21. Such sheet stretcher 7 is used beforehand on top of each of the sheet assemblies 1 and 31 instead of the sheet stretcher 6. As shown in fig. 9, a lashing belt 150 with a buckle 151 is then wound around a scaffolding horizontal member 152 and inserted into the slot 125 to thereby connect the uppermost sheet stretcher 7 to the scaffolding horizontal member 152. When the sheet assembly is heightened gradually in correspondence to the increasing height of a high-rise building in the middle of construction by using sheet stretchers 7 and sequentially stretching the sheets 2 upward gradually in accordance with the progress of construction of the high-rise building, the lashing belts 150 inserted into the slots 125 are connected to the frame to attach the uppermost sheet stretcher 7 in the middle of construction to the frame temporarily. When the sheet 2 is to be stretched further upward after that temporary attachment, the temporary attachment can be removed and a new sheet 2 is applicable at once. In a similar way, the uppermost sheet stretcher 7 can be connected to the scaffolding horizontal member without using an attachment adjuster 44 such as is shown in Fig. 5. Alternatively, a sheet stretcher 7 with a slot 125 may be used instead of the lowermost sheet stretcher 6 in each of the sheet assemblies 1 and 31. In that case, a lashing belt 150 with a buckle 151 may be inserted into the slot 125 in the sheet stretcher 7 as described above, and the present lowermost sheet stretcher 7 may be connected to the scaffolding horizontal member to assemble the sheet assembly. While the corners of the sheet 2 are cut out in the form of a square in the embodiment shown in Fig. 4 the corners 81 of the sheet 2 may be cut out in the form of a triangle only to the degree that the sheet stretcher 7 and the like can be attached to it to form the sheet 2, as shown in Fig. 10. By this construction, the members not covered with the sheet 2 are minimized in area. The sheet 2 may be the one in which many eyelets 21 are formed at equal intervals without expanded portions along the vertical sides thereof, as shown in Fig. 11. When the sheet stretcher 7 with circular holes 126 as shown in Fig. 7 is used, the sheets 2 and the sheet stretcher 7 is preferably connected beforehand by inserting binding lashings such as wire or rope into the eyelets 21 in the sheet 2 and the hole 126 in order to prevent the occurrence of a situation where the sheets 2 would be flapped in wind while the sheet assembly is being assembled, and hence the expanded portion 5 would be removed from the sheet stretcher 7 and the sheet stretcher 7 would fall. As described above, the holes 126 are applicable for the temporary attachment of the sheets 2 to the sheet stretchers 7. When a sheet 202 is used whose thickness of the loop-like edge portion 5 is almost the same as the total thickness of the sheets overlapped at the position 3, as shown in Figs. 12 and 13, a sheet removal preventer 251 is preferably disposed closely in each of the through holes 10, 17, and 19 in the sheet stretchers 6 and 7 around the edge 5 of the sheet 202. The sheet removal preventer 251 comprises a flexible body 252 made of hard or soft vinyl chloride and a bendable metal plate-like core 253 which is buried in the body 252. In the body 252, a plurality of protuberances of teeth 254 is formed at positions where the body 252 touches the surfaces of the sheet 202, especially at positions in the vicinity of the slits 12, 18 and 20 where it touches the sheet 202. The sheet removal preventer 251 prevents the edges 5 of the sheets 202 from being removed from the through holes 10, 17 and 19 through the slits 12, 18 and 20 due to tension exerted on the sheets 202 in the direction A or B. The section of the sheet removal preventer 251 is almost trapezoidal, as shown in Fig. 14, before it is applied to the edge portion 5 of the sheet 202. Therefore, the shape of both sides 255 and 256 of the preventer placed at the position of each of the slits 12, 18 and 20 is wedge-like after it is attached to each of the through holes 10, 17 and 19 in the sheet stretchers 6 and 7. The sheet removal preventer 251 is bent in the opposite directions C to hold and wrap the edge 5 of the sheet 202, as shown in Fig. 14. It is attached to each of the through holes 10, 17 and 19 in the sheet stretchers 6 and 7 with its gripped state being maintained. A semicircular groove 257 as well as a V-like groove 258 may be formed on the body 252 in order to facilitate its bending in the direction C as well as the insertion of the preventer into the through holes 10, 17 and 19 by forming the shape of the preventer after bending so as to correspond to the shape of each of the through holes 10, 17 and 19 in the sheet stretchers 6 and 7. The core member 253 buried in the body 252 holds the shape of the bent preventer 251, so that the holding of the edge 5 of the sheet 202 by the preventer 251 is thereby maintained positively. According to the sheet stretchers 6 and 7 applied to the present sheet assembly 1, only by inserting the sheet removal preventers 251 holding the edges 5 of the sheets 202 gradually into the through holes 10, 17 and 19 at one end to cause the edges 5 of the sheets 202 to be received in the thorough holes 10, 17 and 19, many sheets 202 are stretched very easily in a short time to assemble a sheet assembly. Even if tension is exerted on the sheet 202 in the directions A and B in this assembly, the undesirable removal of the edges 5 of the sheets 202 from the through holes 10, 17, and 19 through the slits 12, 18 and 20 is avoided and a result, the stretched state of the sheets 202 is maintained positively because the edges 5 of the sheets 202 are held firmly by the preventers 251 used in the respective sheet stretchers 6 and 7. Especially, in the sheet removal preventer 251 having both wedge-like sides 255, 256 and teeth 254 of the present embodiment, even if the edges 5 of the sheets 202 are intended to move away from the through holes 10, 17 and 29 through the slits 12, 18 and 20 by the tension exerted on the sheet 202 in the directions A and B, they are pressed strongly by the sheet stretchers 6 and 7 so that both the wedge-like sides 255 and 256 may be closer to each other at the positions of the slits 12, 18 and 20 with the edges 11 of the sheets 202 being bitten firmly by the teeth 254. As a result, the edges 5 of the sheets 202 are surely prevented from being removed from the through holes 10, 17 and 19 through the slits 12, 18 and 20. While in the above embodiment the edge 5 of the sheet 202 is prevented from being removed from the though hole 10 and so on only by the sheet removal preventer 251. In addition, a staple extending through both the sides 255, 256 and the edge portion 11 of the sheet 202 is applicable. Such use of the staple serves to securely prevent the sheet from removal. While the rope 14 is inserted into the holes 13 and 42 to attach the sheet to the scaffolding in the above embodiments, instead of this, hooks or the like provided on a belt with a buckle may be hooked in the hole 13 and 42 to attach the sheet to the scaffolding. Alternatively, a given tension may be added to the sheet 2 so that the sheet 2 may be put up in a tense state by using a belt with a buckle 24 as shown in Fig. 7. A sheet stretcher 301 having semicircular grooves 302 on each side of the central portion thereof as well as a rectangular cavity 303 at the center thereof through the overall length thereof, as shown in Fig. 15, may be used to assemble the sheets. The sheet stretcher 301 in the present embodiment is lightened, excellent in appearance as well as easy to dealt with. According to the present invention as described above, the sheet stretcher has a first hole which slidably receives a expanded portion formed in the edge of the sheet and a first slit communicating with the first hole and through which the edge portion of the sheet formed continuous to its expanded portion is insertable, so that the sheet assembly is obtained in a short time just by Inserting the expanded portion of the sheet into the first hole. Since each sheet stretcher is connected to a sheet stretching frame through the connecting means, the sheet assembly is held firmly to the frame. As a result, a possible swell in the center of the sheet assembly due to a wind and so on is prevented. According to the sheet stretcher wherein a slot through which a string-like member which connects the sheet stretcher to the frame is insertable is disposed between the first and the second holes, and, for example, if the sheet assembly is heightened in correspondence to the increasing height of a high-rise building in the middle of construction by gradually stretching the sheets upwards in accordance with the progress of construction of the high-rise building, its temporary attachment is released and the uppermost sheet stretcher as it is can be used to thereby reduce the working time greatly. In the sheet assembly including the sheet removal preventer disposed in the first hole so as to surround the edge of the sheet in order to prevent the edge of the sheet from being removed from the first hole through the first slit, and even if a sheet with no expanded portion at one end is used, the stretched state of the sheet is maintained securely, and the proper function of the sheet assembly is fulfilled securely without the appearance of the sheets being impaired.

Claims: A sheet stretcher comprising: a base (7a); a first hole (19) provided on the base for slidably receiving an expanded portion (5) formed at an edge (11) of a sheet (2); a first slit (20) provided on the base and continuous to the first hole and through which the edge of the sheet continuous to the expanded portion is insertable; a second hole (17) provided on the base for slidably receiving either an expanded portion (41) of an attachment adjuster (44) having an attachment plate (43) continuous to the expanded portion or a further expanded portion (15) formed at an edge (11) of a further sheet (2); and a second slit (18) provided on the base and formed continuous to the second hole and through which either the attachment plate of the attachment adjuster or the edge of the further sheet formed continuous to the further expanded portion is insertable, the second hole being formed opposite to the first hole and the second slit being formed opposite to the first slit; characterised by: a plurality of slots (125) provided on the base in a line substantially parallel to the longitudinal axis of the base and into each of which a string-like member (14, 150) for connecting the sheet stretcher with a frame is insertable, the slots (125) being disposed between the first and the second holes. A sheet stretcher according to claim 1 wherein the base (7c) is substantially rectangular in cross-section and the slots (125) are disposed in a central portion of the base between the first and second holes, passing through the base.

Inventors: SUZUKI TERUO, SUZUKI, TERUO, SUZUKI, TERUO 1-1006, IRIFUNE 6-CHOME
Applicants: SCS PROMOTION CO LTD, SCS PROMOTION COMPANY LIMITED
Application year: 1991
Main classification: E04G21
IPC codes: E04G21, E04G5, G09F15, E04H15, F16B5