Sheet stretching device

Abstract

A sheet stretching device is provided which is capable of preventing a sheet from being slacked, with the sheet stretched over a frame, by possibly preventing unnecessary motions of a retaining member for fixedly drawing the sheet into the frame. A retaining groove (2a) is formed along the length direction of the frame on the front surface side of a frame (2). Retaining plates (4), with a rectangular cross section, to be fitted into the retaining groove are attached to the peripheral edge portion of a sheet (3). The retaining plate is formed of an elastic material and substantially equal in thickness to the width of the retaining groove. A plurality of projections (4a) at certain intervals in the depth direction of the retaining groove are formed on at least one of the inner wall surface of the retaining groove and the side surface of the retaining plate.

Claims

1. A sheet stretching device comprising: a frame; a sheet; a first retaining groove and a second retaining groove formed on a front surface side of the frame, the first retaining groove defined by an inner wall and an outer wall spaced apart by a width of the first retaining groove, the second retaining groove defined by an inner wall and an outer wall spaced apart by a width of the second retaining groove, and in each of the first retaining groove and the second retaining groove, an inner surface of the inner wall faces an inner surface of the outer wall across the width of the corresponding one of the first and second retaining grooves; and a first retaining plate fit into the first retaining groove and a second retaining plate fit into the second retaining groove, the first and second retaining plates being parallel to each other and fitted into parts of the first and second retaining grooves that are spaced apart and parallel to each other, each of the first and second retaining plates formed of an elastic material and having a rectangular cross section with a first side surface attached to a peripheral edge portion of the sheet, a second side surface opposite to the first side surface, and a thickness substantially equal to the width of the corresponding one of the first and second retaining grooves, wherein in each of the first and second retaining grooves, the first side surface of a respective one of the first and second retaining plates faces the inner surface of a respective one of the outer walls with the sheet disposed therebetween and the second side surface of the respective one of the first and second retaining plates contacts the inner surface of a respective one of the inner walls, the second side surface of one of the first and second retaining plates includes a plurality of projections formed at certain intervals in a depth direction of the corresponding one of the first and second retaining grooves, the first side surface of the one of the first and second retaining plates not including a projection, and in a state in which the first and second retaining plates are positioned to protrude from the parts of the first and second retaining grooves that are spaced apart and parallel to each other, a distance between portions of the retaining plates protruding from the retaining grooves is substantially equal to or less than a distance between the parts of the retaining grooves as a result of the elastic material compressing.

2. The sheet stretching device according to claim 1, wherein the first retaining plate is formed to be shorter than a depth of the first retaining groove, and the second retaining plate is formed to be shorter than a depth of the second retaining groove.

3. The sheet stretching device according to claim 1, wherein a through hole is formed inside each of the first and second retaining plates in a direction along a peripheral shape of the sheet.

4. The sheet stretching device according to claim 1, wherein the frame is formed in a polygonal shape.

5. The sheet stretching device according to claim 1, wherein the first and second retaining grooves are connected and form a continuous retaining groove that extends along at least one edge of the frame.

6. The sheet stretching device according to claim 1, wherein the one of the first and second retaining plates is configured to have multiple positions in a respective one of the first and second retaining grooves, the multiple positions having differing depths in the respective one of the first and second retaining grooves.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a perspective view illustrating an outer appearance of a first embodiment of the present invention.

(2) FIG. 2 is an exploded perspective view of the first embodiment of the present invention.

(3) FIG. 3 is a front view illustrating a sheet of the first embodiment of the present invention.

(4) FIG. 4 is a rear view illustrating the sheet of the first embodiment of the present invention.

(5) FIG. 5 is an enlarged cross-sectional view, taken along line V-V of FIG. 4, illustrating the first embodiment of the present invention.

(6) FIG. 6 is an enlarged cross-sectional view illustrating a main portion in the procedure of stretching a sheet according to the first embodiment of the present invention.

(7) FIG. 7 is an enlarged cross-sectional view illustrating the main portion in the procedure of stretching the sheet according to the first embodiment of the present invention.

(8) FIG. 8 is an enlarged cross-sectional view illustrating the main portion in the procedure of stretching the sheet according to the first embodiment of the present invention.

(9) FIG. 9 is an enlarged cross-sectional view illustrating a main portion according to a modified example of the present invention.

(10) FIG. 10 is an enlarged cross-sectional view illustrating a main portion according to another modified example of the present invention.

DESCRIPTION OF EMBODIMENTS

(11) A description will next be given of a first embodiment of the present invention with reference to the drawings.

(12) In the figures, reference numeral 1 denotes a billboard to which this embodiment is applied and which is provided with a rectangular frame 2, and a sheet 3 that is stretched across the front surface of the frame 2 so as to cover a portion surrounded by the frame.

(13) As shown in FIG. 2, the front surface of the frame 2 is provided with a retaining groove 2a formed along the length direction, and as shown in FIG. 6, the retaining groove 2a is formed with a substantially constant width along the total length of the frame 2 and thus formed in the same rectangular shape as the frame 2.

(14) The sheet 3 is formed of cloth or a resin film, and has similitude relations with and slightly larger in shape than the rectangular shape defined by the retaining groove 2a. For example, preferredly employed as the sheet 3 is a sheet with a logo or ads printed, a plain sheet, a cloth sheet, or a decorative pattern sheet.

(15) Then, as shown in FIG. 2 to FIG. 4, the rear surface of the sheet 3 is provided with four retaining plates 4 fixedly attached thereto along each side of the peripheral edge portion thereof.

(16) For example, these retaining plates 4 are formed of an elastic material such as a silicone resin, and the distance between opposing parallel retaining plates 4 is set to be substantially equal to or less than the distance between opposing parallel retaining grooves 2a among those formed in 10 the frame 2. For example, as shown in FIG. 2, opposing retaining grooves 2a include parts 2b that are spaced apart and parallel to each other. Two of the retaining plates 4 provided along opposite edge portions of the sheet 3 are inserted into the parts 2b of retaining grooves 2a. For example, the retaining plates 4 can be formed of cardboard, corrugated cardboard, or foam materials.

(17) Furthermore, the thickness of each of the retaining plates 4 is substantially the same as the width of the retaining groove 2a, and as shown in FIG. 5, a plurality of projections 4a at certain intervals in the width direction (the right-and-left direction in FIG. 5) are formed on one side in the thickness direction.

(18) As shown in FIG. 5, on the side on which no projections 4a are formed, such retaining plates 4 are fixedly attached to the peripheral edge portion of the sheet 3 with an adhesive 5 such as double-sided tape.

(19) Note that methods for attaching the sheet 3 to the retaining plates 4 are conceivable to include, in addition to sewing, a method using a stapler, a method utilizing adhering, fusing, or melting, and a method using a structural function for sandwiching the plate.

(20) Next, referring to FIGS. 6 and 7, a description will be given of the steps of stretching the sheet 3 over the frame 2 according to this embodiment that is configured as described above.

(21) First, as shown in FIG. 6, the peripheral edge portion of the sheet 3 is bent so that the retaining plate 4 is located on the rear surface side, and then the retaining plate 4 is inserted into the retaining groove 2a of the frame 2.

(22) Next, the retaining plate 4 is further pushed into the retaining groove 2a until, as shown in FIG. 7, part of the retaining plate 4 is positioned to be protruded from the retaining groove 2a.

(23) Here, when the distance between the retaining plates 4 is set to be less than the distance between the retaining grooves 2a, the difference therebetween is accommodated by the elastic deformation of the protruded portion of the retaining plate 4 as shown in FIG. 7.

(24) On the other hand, the portion other than the protruded portion is pushed into the retaining groove 2a so as to be pushed under pressure against both the inner walls of the retaining grooves 2a.

(25) Here, one side surface of the retaining plate 4 is brought into contact with one inner surface of the retaining groove 2a in conjunction with the sheet 3, and the other side surface is brought into contact with the inner wall of the retaining groove 2a via the plurality of projections 4a at a plurality of points at certain intervals in the depth direction.

(26) If an external force is applied in the depth direction of the retaining groove 2a, this configuration causes the retaining plates 4 to be moved so as to be dislodged therefrom. However, an external force in a direction other than the depth direction would cause the retaining plates 4 to hold the positions thereof.

(27) Thus, the retaining plates 4 are secured with reliability to the position protruded from the retaining groove 2a, allowing the protruded portion to be held in an elastically deformed state.

(28) This allows the sheet 3 to be stretched while being provided with tension by the elasticity of the retaining plates 4.

(29) As a result, when stretched, the sheet 3 is normally provided with tension and prevented from being slacked, and maintains the effects of design thereof.

(30) On the other hand, more tension may need to be applied to the sheet 3, for example, when the sheet 3 is slacked due to the elongation of the sheet 3. In this case, as shown in FIG. 8, this need can be satisfied by further pushing the retaining plates 4 into the retaining groove 2a.

(31) Such a manipulation causes the protruded portion of the retaining plates 4 to be pushed into the retaining groove 2a, and thereby pushed outwardly.

(32) As a result, the tension given to the sheet 3 is increased to thereby eliminate the slack.

(33) Then, adjusting the position of the retaining plate 4 being pushed in enables the tension given to the sheet 3 to be adjusted, thus facilitating adjustment of the tightness of the sheet 3.

(34) On the other hand, as described above, the retaining plates 4 are effectively prevented from being moved by an external force, such as the tension, in a direction intersecting the depth direction of the retaining groove 2a, but can be relatively easily moved by an external force in the depth direction of the retaining groove 2a because of the reduction of frictional resistance caused by the presence of the projections 4a.

(35) Thus, the retaining plates 4 can be relatively easily extracted or inserted, thereby enabling replacement of the sheet 3 in a simplified manner.

(36) Note that the various shapes and sizes of each of the components illustrated in the embodiment were shown only as an example, and thus may be modified in a variety of ways according to design requirements.

(37) For example, in the embodiment, such an example was shown in which the projections 4a are formed on the retaining plate 4. However, the projections 4a may be formed on the inner wall of the retaining groove 2a, or alternatively, may also be formed on both the retaining plate 4 and the retaining groove 2a.

(38) Furthermore, in the embodiment, the rectangular frame 2 was illustrated as an example. However, the frame 2 may also be formed in a triangular shape, in a polygonal shape with five or more corners, or alternatively in a circular shape.

(39) Furthermore, as shown in FIG. 9, it is also possible to form through holes 4b in the retaining plate 4.

(40) This enables fine adjustments of the tension given to the sheet 3 by reducing the elastic modulus of the retaining plate 4.

(41) Furthermore, as shown in FIG. 10, one side portion of the retaining plate 4 may also be provided with a reduced-thickness portion 4c.

(42) Such a structure enables the retaining plate 4 and the sheet 3 to be connected to each other at the reduced-thickness portion 4c using a fixing member 6 such as a stapler.

(43) That is, if the retaining plate 4 is increased in thickness when using the fixing member 6 like a stapler, the fixing member 6 will be less prone to being penetrated through the retaining plate 4, allowing the retaining plate 4 to be connected with difficulty.

(44) In this context, forming the reduced-thickness portion 4c described above facilitates penetration of the fixing member 6 like the stapler to thereby enable connection with the fixing member 6.

(45) The retaining plate 4 and the sheet 3 are connected to each other with the fixing member 6 that penetrates therethrough, thereby significantly improving the connection strength therebetween.

(46) Note that for materials of the retaining plate 4, a plurality of materials can be used, thereby achieving cost reduction and high productivity. Examples thereof may include applying a resin to cardboards, enabling domestic sewing machines to sew cloth attached to a resin, applying a resin to cloth itself, or combining a push support vinyl chloride plate material with a foaming material.

(47) Furthermore, in the aforementioned embodiments, such an example was illustrated in which the frame is provided with the retaining groove 2a, and the retaining plates 4 with the sheet 3 attached thereto are inserted into the retaining groove 2a, thereby stretching the sheet 3. It is also possible to employ such a structure in which the retaining groove 2a may be provided, for example, on a wall surface, and the retaining plates 4 with the sheet 3 attached thereto are inserted into the retaining groove on the wall surface, thereby stretching the sheet 3. Furthermore, without being limited to the wall surface, for example, it is also possible to employ such a structure in which the retaining groove 2a may be provided on the surface of a rectangular plate material, and the sheet 3 is stretched over the surface of the plate material.

REFERENCE SIGNS LIST

(48) 1 billboard 2 frame 2a retaining groove 3 sheet 4 retaining plate 4a projection 4b through hole 4c reduced-thickness portion 5 adhesive 6 fixing member