GB1576479A - Foldable structure of rectangular prismatic form - Google Patents

Description

(54) IMPROVEMENTS IN AND RELATING TO A FOLDABLE STRUCTURE OF RECTANGULAR PRISMATIC FORM (71) We, TOKO CURTAIN KABUSHIKI KAISHA, No. 14-5, 1-chome, Yotsui, Fukui City, Fukui Prefecture, Japan, a Japanese corporation, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: In general, structures of a rectangular prismatic form, such as a bed, workbench, desk, or stage of known type have in the past been of fixed form with given area and height, always occupying a definite space, whether in use or not, thus not permitting use of the corresponding space for other purposes.

Therefore, a combination chair and bed capable of being expanded and contracted has recently been proposed. This consists of flexible structural means, comprising a number of arm pieces of equal length, being cross-linked so as to permit expansion and contraction thereof, the structural means also forming the top boards and side boards of such a rectangular prismatic structure. The structure is so made that it will funtion as a chair when it is contracted and as a bed when it is expanded.However, in this flexible type of a combination chair and bed, the load on the upper surface thereof is supported by the flexible structural means of cross-linked type, where the rigidity of such structural means will invariably be reduced when the structure is expanded, thereby resulting in a downward flexure due to reduced supporting strength even though the load may remain unchanged, thereby constituting a defect in the basic design concept. When such a structure is used as a bed, this flexure implies bending of the supporting surface, thus resulting in a very uncomfortable bed.

Although it would be possible to provide reinforcing members for preventing on minimizing this flexure, such reinforcing members will invariably lower the flexibility of such a structure in its expansion and contraction function and also make the construction very complex, thereby making it almost impractical to provide adequate reinforcement. Further, due to excessive load being exerted on the hinged coupling, both axles and bearings are liable to be deformed in repeated expansion and contraction movements, thus resulting in loose joints and eventually in loose structure as a whole.

This invention, being a result of new development so as to eliminate the above defects found in the foldable structure of the prior art, relates to a new foldable structure of rectangular prismatic form which employs several single units in combination, can be used as a bed, workbench, or desk, the units being capable of being folded together in minimal space when not in use, and which structure can be placed in service by easily and rapidly generating a surface with given area and height. It is therefore an object of the invention to provide a foldable structure of rectangular prismatic form whose work area and height can be varied easily and rapidly, by the use of a plurality of such single units linked together.

Still another object of this invention is to provide a foldable structure of rectangular prismatic form having its frame members and plates fitted into such frame members made of light-weight materials such as aluminium, plastics, or wire netting so as to reduce its overall weight, and at the same time to permit placing of desired colour scheme or designs so as to increase its commodity value.

A further object of this invention is to provide a foldable structure of rectangular prismatic form which can be used as a bed, workbench, or desk.

According to this invention there is provided a foldable structure of rectangular prismatic form comprising at least two single units, each single unit comprising two paral lel legs connected by a perpendicular crosspiece, a first top board hingedly connected along one of its transverse edges to said crosspiece and hingedly connected along another of its transverse edges, parallel to said one of its edges, either directly or through an intermediate hinge-bearing board to a similar first edge of a second top board, a pair of side frames, each side frame having a first side frame member hingedly connected along one of its edges to one of said legs and hingedly connected along another of its edges, parallel to said one of its edges, to a first edge of a second frame member of the side frame, the second top board of each single unit, except the final single unit of the structure, being hingedly connected along a second edge, parallel to said first edge, to the crosspiece of the other or another single unit and the second side frame members of said one single unit being hingedly connected along respective second edges thereof, parallel to their first edges, to the legs of said other or said another single unit, the final single unit having additionally two further parallel legs connected by a perpendicular crosspiece to which the second top board and second side frame members of said final single unit are respectively connected, said top boards in an unfolded position of the or each unit forming a flat surface and being supported by said side frames, the hinge connections between the legs and the side frame members and also between the crosspieces and the top boards, each comprising a part-cylindrical bearing axle on one of the hmge parts and a complementary part-cylindrical recess on the other of the hinge parts.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 represents a final single unit of foldable structure of rectangular prismatic form constructed according to this invention and shows the unit formed into its unfolded shape; Figure 2 is a perspective view of a similar final single unit of a foldable structure of rectangular prismatic form constructed in accordance with a further embodiment of the invention; Figure 3 shows a final single unit in the process of being folded, side frames thereof as well as top boards thereof being folded simultaneously.

Figure 4 shows the final single unit of Figure 3 when folding has been completed; Figure 5 is an enlarged fragmentary sectional view of the top boards of the unit of Figure 3 showing a hinge construction thereof; Figure 6 is an enlarged fragmentary sectional view similar to that of Figure 5, showing another example of the hinge construction; Figure 7 is an enlarged fragmentary sectional view of the side frames of the unit, showing a hinge construction; and Figure 8 is a perspective view of a long interconnected structure, consisting of four single units linked to each other for use as a bed, showing a condition where some of the units are folded and the others are unfolded to provide an upper supporting surface.

A foldable structure of rectangular prismatic form according to this invention consists of a final single unit A shown in Figures 1 to 4, linked to a plurality of other single units of exactly the same form but each having only one pair of parallel legs connected by a perpendicular crosspiece. When linked together to form a continuous structure, each single unit, except the final single unit, is connected at its end without legs and a crosspiece to the legs and crosspiece of an adjacent single unit.

The final single unit A consists of two pairs of parallel legs 1 connected by a crosspiece perpendicular thereto. Each pair of legs and associated crosspiece are of rectangular form when assembled, and the two pairs of legs are spaced apart so that two flat top boards 2 can be provided between such pairs of legs 1 to form a single top surface, the boards also being foldable upwardly at respective hinges in the centre of such top surface. Two sets of two side frame members 5a, Sb, are provided between the pairs of legs to form two sides of the rectangular prismatic structure, each set of side frame members also being foldable inwardly at the hinge in the centre of each side plane. The hinge construction which permits folding between the legs 1 and top boards 2, respectively is shown in Figure 5.

Desirably between the two flat top boards 2, is located a middle hinge-bearing board 3, extending in parallel with the planes containing the legs 1. A bearing axle 3a of partcircular cross-section is formed on each side of the above hinge board 3, and a bearing 2c of circular arc cross-section, being formed on each corresponding side of the above top boards 2, is slipped fittingly onto this bearing axle 3a, both the axle 3a and bearing 2c being fully rotative. This hinge board 3 shall be so constructed that its width is made equal to or slightly larger than the total thickness of the top boards 2 that it can cover upper edges of the top boards when they are folded together as shown in Figure 4.

A bearing axle 9a of part-cylindrical form 9a is provided on both sides of the crosspiece of each pair of legs 1, the axles running parallel to the longitudinal direction of the crosspiece. One bearing 2d in the form of a recess of circular arc cross-section is provided on each corresponding side of the top boards 2 to accommodate axle 9a. Bearing 2d is slipped fittingly onto the axle 9a, joining the crosspieces and top boards rotatively together.

A bearing axle 3a of part-cylindrical form on the hinge board 3 is formed to protrude downwardly therefrom, and bearing axles 9a on the crosspieces are formed to protrude upwardly therefrom. Thus, the relative rotation of bearings 2c and 2d, which fit onto axles 3a and 9a respectively, will push the hinge board 3 upwardly. It will be easily understood that this relative movement will fold the top boards 2 towards each other, drawing the pairs of legs 1 closer together, thus folding the structure.

A shoulder 3b on each side of the hinge board 3, and a shoulder 2e on a corresponding side of each of the top boards 2 respectively constitute surfaces in abutting contact with each other, when top boards 2 are positioned to form a flat, horizontal, surface as shown in phantom in Figure 5. The presence of such abutting surfaces will permit the top boards 2 to act as a load bearing surface to adequately withstand the load applied on such a surface, thus increasing load carrying capacity and rigidity of the structure. Abutting contact surfaces of this type are provided between shoulders 2f, 9b, located underneath the hinge formed by bearing axles 9a and bearing 2d, which join the crosspieces and top boards 2 together. These contact surfaces also increase load bearing capacity and rigidity of the structure in the same manner.

Each of the top boards 2 consists of a circumferential frame 2a, which serves as a strengthening member, and a surface board 2b, which is fixed within such a frame. When the frame 2a, a strengthening member, is placed on top of the above side frames 5, in a manner to be described later, the top boards 2 will possess adequate strength to maintain themselves in a horizontal position. The frame can be fabricated from, for example, aluminium or plastics material. The surface board 2b can be of any material which will withstand and not be damaged by the load applied on the top board 2 and which will permit placement of a desired design thereon so as to increase its commodity value.

Further, it is needless to say that the top board 2 can be made of a single member, rather than consisting of two parts, i.e. frame 2a and surface board 2b.

Each pair of legs 1 and each associated connecting crosspiece comprises a channel shaped member ib fitted on a rectangular framework la. The member ib forming the crosspiece connecting a pair of legs 1 is fitted onto a horizontal upper part of the framework la whilst the members ib forming the vertical legs 1 are fitted onto vertical parts of the framework la, as shown in Figures 5 to 7. The member ib forming the crosspiece has a part-cylindrical axle 9a protruding on both sides, and is so constructed that it is fittingly slipped onto the framework la, being firmly attached thereon by means of a screw 10.The crosspiece and framework may alternatively be constructed as one unit, combining the framework la and the member 1b as an integral element, as shown in Figure 6.

Between each of the two side frame members 5 of the side frames is located a middle hinge board 6, which is positioned vertically.

A bearing axle 6a of part-cylindrical form is provided on each side of the hinge board 6, and a bearing axle Sa in the form of a recess of circular arc cross-section, formed on each corresponding end of the above side frame members 5, is fittingly slipped onto this bearing axle 6a, thereby connecting the hinge board 6 and the side frame members 5 rotatively through two hinges and permitting folding of the side frames respectively in the middle of each side plane. Together with the above arrangement, a vertically extending bearing axle axis 8a of part-cylindrical crosssection on leg members 1b will be inserted fittingly into the bearing axle Sb of circular arc cross-section at the respective adjacent ends of the side frame members 5, thereby connecting the leg and the side frames rotatively together.While the connection of such side frame members 5 through hinges is of the same construction as the case for connection of the above top boards 2 through hinges, a slight difference lies in the fact that side frames fold inwardly into the space of the structure whereas the top boards 2 fold upwardly. Moreover, rigidity of the side frame members 5 is increased when they are positioned in the same plane, by having shoulders 6b on both sides of the middle hinge board 6 in abutting contact with shoulders Sc on corresponding sides of the side frame members 5, and also by having shoulders Sd, 8b, on side frame members 5 and leg members 1b respectively, in abutting contact with each other.

The side frame members 5 are, in the exemplary embodiment shown by the drawing, of rectangular frame form, having an opening in the centre. However, it is needless to say that the frame members need not be confined to such a form only. A frame member can be made of a single board, or can consist of a rectangular frame and an inner board, the latter being fitted into the frame. Such boards in the side frame members can serve as decoration by placing desired pattern and colour schemes thereon.

In the exemplary embodiment shown in Figure 7 of the drawings, a leg member lb, having a bearing axle 8a protruding on both sides, is so constructed that it is fittingly slipped onto the framework la, being firmly attached thereon by means of a screw 11.

The member 1b should not be confined to such a form only, and an integral form com bining both the member ib and the framework la can be used.

The total length p of the two top boards 2 is equal to or smaller than the total length a of the two side frame members in Figures 1 and 2. Figure 1 shows a condition where the structure is so made to be a = ss. When such a single unit A is unfolded, both top boards 2 and side frames are unfolded and extended into a straight line. Figure 2 shows a condi tion where the structure is so made to be a p. In this case, the side frame members 5 remain in partially folded condition, while the top boards 2 are in a straight line.

As shown in Figure 1 or Figure 2, when top boards 2 are unfolded and extended into a horizontal surface, the top boards 2 are placed on and supported by the upper end of the side frames, which are located below both ends of the top boards and are in vertical position. As a result, top boards 2 con stituting upper surfaces of the unfolded structure, are maintained in a perfectly hori zontal position and adequate- structural rigid ity will simultaneously be secured. Accord ingly, this structure provides high strength against a load applied on top boards 2. As shown in Figure 2, when the structure is so made to be a > ss, where side frame mem bers 5 remain in partially folded condition, the strength against buckling will further increase, thereby providing a foldable struc ture of still larger load bearing capacity.

When the structure is folded, top boards 2 are firstly lifted upward and side frame members 5 pushed inwardly, and thereafter, as shown in Figure 3, as top boards 2 are further lifted upward, the side frame mem bers 5 are folded simultaneously with top boards 2, and the whole structure is folded into a flat shape as shown in Figure 4. In this folded condition, the space occupied by the folded structure becomes extremely small, thereby making the large space previously occupied by the structure almost fully avail able as a free space, permitting effective use of the space otherwise occupied by the extended structure.As shown in Figure 2, when the structure is so make to be a > since side frame members 5 are already in partially folded condition, it is no longer necessary to firstly push side frame members 5 inwardly, as is the case for a previously described structure where a = ss, thereby permitting folding operation of the entire structure by simply lifting top boards 2 upwardly.

Figure 8 shows a long bed structure having desired length (and height), formed by link ing together four single units A, one of which is a final single unit as previously described in Figures 1 to 7 and the other three of which have only one pair of parallel legs connected by-a cross-piece.

As already described, a continuous structure is formed by each single unit, except the final single unit, being connected at its end without a pair of legs connected by a crosspiece, to the pair of legs and crosspiece of an adjacent single unit. This is shown in Figure 8 and it can also be appreciated therefrom that the single unit adjacent the final single unit is connected at its end without a pair of legs and a crosspiece, to one of the two pairs of legs and crosspiece of the final single unit.

Bearing axle 2d on top board 2 and bearing axles Sb on side frame members 5 at one end of each single unit, except the final single unit, will be fittingly slipped onto bearing axles 9a and 8a respectively protruding from the legs 1 and connecting crosspiece of an adjacent unit.

Further shown in the drawing are castors 12 on the legs 1 and juncture boards 13, the latter covering the ends of hinge boards 3, 6, so as to make respective ends neatly finished and also to provide protection against possible damage due to their being hit by other objects.

When these units are made into a bed structure, the surface board 2b to be fixed in the centre of top board 2 can be of perforated board or wire netting so as to improve its quality as a bed. Further, on the crosspieces forming the ends of the bed structure, a head board and a foot board may be respectively fitted.

WHAT WE CLAIM IS: 1. A foldable structure of rectangular prismatic form comprising at least two single units, each single unit comprising two parallel legs connected by a perpendicular crosspiece, a first top board hingedly connected along one of its transverse edges to said crosspiece and hingedly connected along another of its transverse edges, parallel to said one of its edges, either directly or through an intermediate hinge-bearing board to a similar first edge of a second top board, a pair of side frames, each side frame having a first side frame member hingedly connected along one of its edges to one of said legs and hingedly connected along another of its edges, parallel to said one of its edges, to a first edge of a second frame member of the side frame, the second top board of each single unit, except the final single unit of the structure, being hingedly connected along a second edge, parallel to said first edge, to the crosspiece of the other or another single unit and the second side frame members of said one single unit being hingedly connected along respective second edges thereof, parallel to their first edges, to the legs of said other or said another single unit, the final single unit having additionally two further parallel legs connected by a perpendicular crosspiece to which the second top board and second side frame members of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (1)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   such a form only, and an integral form com bining both the member ib and the framework la can be used.

   The total length p of the two top boards 2 is equal to or smaller than the total length a of the two side frame members in Figures 1 and 2. Figure 1 shows a condition where the structure is so made to be a = ss. When such a single unit A is unfolded, both top boards 2 and side frames are unfolded and extended into a straight line. Figure 2 shows a condi tion where the structure is so made to be a p. In this case, the side frame members 5 remain in partially folded condition, while the top boards 2 are in a straight line.

   As shown in Figure 1 or Figure 2, when top boards 2 are unfolded and extended into a horizontal surface, the top boards 2 are placed on and supported by the upper end of the side frames, which are located below both ends of the top boards and are in vertical position. As a result, top boards 2 con stituting upper surfaces of the unfolded structure, are maintained in a perfectly hori zontal position and adequate- structural rigid ity will simultaneously be secured. Accord ingly, this structure provides high strength against a load applied on top boards 2. As shown in Figure 2, when the structure is so made to be a > ss, where side frame mem bers 5 remain in partially folded condition, the strength against buckling will further increase, thereby providing a foldable struc ture of still larger load bearing capacity.

   When the structure is folded, top boards 2 are firstly lifted upward and side frame members 5 pushed inwardly, and thereafter, as shown in Figure 3, as top boards 2 are further lifted upward, the side frame mem bers 5 are folded simultaneously with top boards 2, and the whole structure is folded into a flat shape as shown in Figure 4. In this folded condition, the space occupied by the folded structure becomes extremely small, thereby making the large space previously occupied by the structure almost fully avail able as a free space, permitting effective use of the space otherwise occupied by the extended structure.As shown in Figure 2, when the structure is so make to be a > since side frame members 5 are already in partially folded condition, it is no longer necessary to firstly push side frame members

   5 inwardly, as is the case for a previously described structure where a = ss, thereby permitting folding operation of the entire structure by simply lifting top boards 2 upwardly.

   Figure 8 shows a long bed structure having desired length (and height), formed by link ing together four single units A, one of which is a final single unit as previously described in Figures 1 to 7 and the other three of which have only one pair of parallel legs connected by-a cross-piece.

   As already described, a continuous structure is formed by each single unit, except the final single unit, being connected at its end without a pair of legs connected by a crosspiece, to the pair of legs and crosspiece of an adjacent single unit. This is shown in Figure 8 and it can also be appreciated therefrom that the single unit adjacent the final single unit is connected at its end without a pair of legs and a crosspiece, to one of the two pairs of legs and crosspiece of the final single unit.

   Bearing axle 2d on top board 2 and bearing axles Sb on side frame members 5 at one end of each single unit, except the final single unit, will be fittingly slipped onto bearing axles 9a and 8a respectively protruding from the legs 1 and connecting crosspiece of an adjacent unit.

   Further shown in the drawing are castors 12 on the legs 1 and juncture boards 13, the latter covering the ends of hinge boards 3, 6, so as to make respective ends neatly finished and also to provide protection against possible damage due to their being hit by other objects.

   When these units are made into a bed structure, the surface board 2b to be fixed in the centre of top board 2 can be of perforated board or wire netting so as to improve its quality as a bed. Further, on the crosspieces forming the ends of the bed structure, a head board and a foot board may be respectively fitted.

   WHAT WE CLAIM IS: 1. A foldable structure of rectangular prismatic form comprising at least two single units, each single unit comprising two parallel legs connected by a perpendicular crosspiece, a first top board hingedly connected along one of its transverse edges to said crosspiece and hingedly connected along another of its transverse edges, parallel to said one of its edges, either directly or through an intermediate hinge-bearing board to a similar first edge of a second top board, a pair of side frames, each side frame having a first side frame member hingedly connected along one of its edges to one of said legs and hingedly connected along another of its edges, parallel to said one of its edges, to a first edge of a second frame member of the side frame, the second top board of each single unit, except the final single unit of the structure, being hingedly connected along a second edge, parallel to said first edge, to the crosspiece of the other or another single unit and the second side frame members of said one single unit being hingedly connected along respective second edges thereof, parallel to their first edges, to the legs of said other or said another single unit, the final single unit having additionally two further parallel legs connected by a perpendicular crosspiece to which the second top board and second side frame members of

   said final single unit are respectively connected, said top boards, in an unfolded position of the or each unit forming a flat surface and being supported by said side frames, the hinge connections between the legs and the side frame members and also between the crosspieces and the top boards, each comprising a part-cylindrical bearing axle on one of the hinge parts and a complementary part-cylindrical recess on the other of the hinge parts.

   2. A foldable structure as claimed in claim 1 wherein in a single unit the total length of the two top boards alone or of the two top boards and the hinge-bearing board is equal to or smaller than the total length of the two side frame members of the single unit.

   3. A foldable structure as claimed in claim 1 or claim 2 wherein a plurality of single units are linked together to provide a flat surface having a suitable area for use as a bed, the bed being equipped with a head board and a foot board, such head board and foot board being fitted above the crosspieces which form the ends of the bed.

   4. A foldable structure as claimed in any one of the claims 1 to 3 wherein the top boards and side frame members have respective shoulders which come into abutting contact with shoulders at their respective associated bearing axles when the units are unfolded.

   5. A foldable structure of rectangular prismatic form substantially as hereinbefore described with reference to as shown in Figures 1 to 7 or Figure 8 of the accompanying drawings.