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GB2427415A - Collapsible structure with drawstring operated folding support - Google Patents

️Wed Dec 27 2006

2427415

- 1 -

A STRUCTURE

Field of the Invention

This invention relates to a structure, in particular to a collapsible structure and more 15 particularly to a collapsible structure for a bed.

Background to the Invention

There is a demand for occasional beds that can be stored and transported easily, that are quick and simple to erect and that are comfortable to sleep on. Commonly, this need is 20 satisfied by inflatable beds that are pumped up before use. However, such beds can take a relatively large amount of time and effort to inflate and are not always particularly comfortable.

This invention, at least in the presently preferred embodiments, seeks to provide a 25 structure that can be used to make a comfortable, easily erectable and transportable occasional bed.

Summary of the Invention

The invention provides a structure comprising a first panel and a second panel arranged in 30 facing relation to the first panel and biased towards the first panel. The structure further comprises a first support member hingedly connected to the first panel and hingedly connected to the second panel and having a first main hinge between its ends, whereby

movement of the first panel towards the second panel causes the first support member to fold about the first main hinge. The structure further comprises a second support member hingedly connected to the first panel and hingedly connected to the second panel and having a second main hinge between its ends, whereby movement of the first panel 5 towards the second panel causes the second support member to fold about the second main hinge. A resilient member is connected between the first and second support members and is arranged to resist relative movement of the first and second support members in opposite directions, whereby the resilient member resists the biasing of the first panel and the second panel towards each other when the support members are folded 10 in opposite directions.

According to the invention, the first and second panels are biased towards each other but are held apart by the scissor action of the support members and the restoring action of the resilient member. Thus the first (or second) panel provides a sprung surface to sleep on 15 which is created by a very simple structure.

In the preferred embodiment, the first panel can be collapsed towards the second panel by folding the support members in the same direction. In this way, the structure can be collapsed by moving one of the support members into a position where it folds in the 20 same direction as the other support member so that the resilient member no longer acts to restrain the bias of the panels towards each other. In general, in the erected structure, the resilient member acts to resist relative movement of the support members away from each other and is therefore in tension. When the folding direction of one support member is reversed, the resilient member ceases to be in tension and the structure collapses.

The first panel and/or the second panel may have a space defined therein for receiving the folded support members when the structure is collapsed. In this way, when the first and second panels come together the collapsed structure is as thin as possible. Thus, the support members may also be configured such that they do not overlap when the structure 30 is collapsed. For example one support member may be configured with a space to receive the other folded support member. In the preferred embodiment, the second support member is U-shaped when completely folded and receives the first support member between the limbs of the U-shape.

Conveniently, the support members may be formed of material cut out of the first and/or second panel. By cutting the support members from the material of the panel(s), a space for the completely folded support members is automatically created in the panel(s). In 5 addition, the support members may be manufactured conveniently with the panel(s). In this case, "cutting out" of the material does not imply any particular method of manufacture, but relates to the shape of the panels and support members. Thus, the panels and support members may be moulded into the required shape, for example.

10 Advantageously, the support members may be formed integrally with the first and/or second panels. For example, the hinges between the support members and one or both panel(s) may be formed by deforming or shaping the material of the panels. One or both support members may be formed in one of the panels and then connected to the other panel, for example by a hinge.

In one particular embodiment, each support member comprises a first limb formed integrally with the first panel joined to a second limb formed integrally with the second panel. In this case, the resilient member may be connected to the support member at the joint between the first and second limbs. This is particularly advantageous in that the 20 resilient member may be connected to the support member in single operation with the joining of the limbs of the support member.

The support members and/or the first and second panels may be composed of polypropylene. The use of polypropylene enables a lightweight structure to be created in 25 which the hinges can be formed integrally.

The resilient member may be made of any suitable material, such as rubber or elastomer. In the presently preferred embodiment, the resilient member is made of woven elastic. Conveniently, the resilient member is connected to the main hinges of the support 30 members as these undergo the greatest movement. However, the resilient member may be connected between any moving parts of the support members.

The first panel and the second panel may be composed of flexurally resilient material, such as polypropylene. The panels may be connected (directly or indirectly) to each other in a peripheral region such that the panels are biased towards each other by their flexural resilience. In this way, the unfolding support members push the panels apart to form an 5 envelope between the panels. However, it is possible for the panels to be biased towards each other by other means, such as further resilient members. Connecting the peripheries of the panels has the advantage, though, of increasing the stability of the erected structure.

The structure may further comprise an externally accessible line arranged to pull the first 10 support member between a position in which it is folded in the same direction as the second support member and a position in which it is folded in the opposite direction to the second support member. Thus, the structure may be erected by pulling the line, such as a cord or strap. In the preferred embodiment, the line is provided with lugs that can move relative to the first support member but engage the first support member for erection and 15 collapse. In this way, the line does not inhibit the free movement of the first support member.

The structure may comprise a plurality of first support members hingedly connected to the first panel and hingedly connected to the second panel and each having a first main hinge 20 between their ends, whereby movement of the first panel towards the second panel causes the first support members to fold about their first main hinges. The structure may further comprise a plurality of second support members hingedly connected to the first panel and hingedly connected to the second panel and each having a second main hinge between their ends, whereby movement of the first panel towards the second panel causes the 25 second support members to fold about their second main hinges. The structure may further comprise a plurality of resilient members connected between respective first and second support members, arranged to resist relative movement of the respective first and second support members in opposite directions.

30 The first and second support members may be arranged in a plurality of rows, each row comprising a plurality of first support members and a plurality of second support members. In the preferred embodiment, the rows of support members are arranged for independent relative movement. This allows for greater comfort for the sleeper.

The invention extends to a collapsible bed comprising a structure according to the invention. However, the invention may also be used in other applications, such as sofas, furniture, sprung flooring or the like.

Brief Description of the Drawings

An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 shows a folding bed according to an embodiment of the invention in the folded 10 position for carrying;

Figure 2 shows the bed of Figure 1 in the position of use and partially erected;

Figure 3 is an exploded view illustrating the construction of the bed of Figure 1;

Figure 3A is an enlarged view of the detail of Figure 3 as indicated by the circle B in that figure;

15 Figure 4 is a sectional view along line A-A of Figure 1 illustrating the construction of the bed;

Figure 5 is an enlarged view of the detail of Figure 4 as indicated by the circle C in that figure; and

Figures 6A to 6D show a constructional unit of the bed of Figures 1 to 5.

Detailed Description of an Embodiment of the Invention

Figures 1 and 2 show a folding bed according to an embodiment of the invention. The bed is configured as a substantially planar panel which can be erected in the manner described below into a three-dimensional sprung structure as shown in Figure 2. The 25 unerected, flat bed is formed of six panels separated by fold lines 2 along which the panels can be folded together for carrying and storage, as shown in Figure 1. The folded bed is secured with removable elastic straps 4 during transport or storage. A carrying handle 6 is formed at each longitudinal end of the bed and the carrying handles 6 from each end come together when the bed is in the folded position so that the folded bed can 30 be carried easily.

As shown in Figure 3, the bed is composed of four layers: a lower structural layer 8, an upper structural layer 10, a top layer 12 and a cover layer 14. The cover layer 14 is

uppermost in the position of use and in this embodiment is composed of ribbed fabric to provide a relatively soft sleeping surface for the user of the bed. Below the cover layer 14, the top layer 12 is composed of sheet polypropylene and provides structural integrity to the upper surface of the bed. However, a plurality of transverse slits 16 are rotary die 5 cut in the top layer 12, to define respective slats 18 between adjacent slits 16. The slats 18 can move independently of each other in the vertical direction, in use, to enable the bed more easily to accommodate the contours of the sleeping user and therefore enhance comfort.

10 The upper structural layer 10 is also formed of sheet polypropylene and is rotary die cut with a repeating pattern of structural elements 20, the detail of which is shown in Figure 3A. The structural elements 20 are formed in rows, with each row positioned directly below a corresponding slat 18 of the top layer 12. In this embodiment, each row comprises five structural elements 20 and there are 30 rows (five per folding panel). The

15 rows of structural elements 20 are separated by slits 22 which correspond in position to the slits 16 in the top layer 12. Again, this allows the rows of structural elements 20 to move independently of each other for enhanced comfort. The structural elements 20 will be described in more detail below. The carrying handles 6 of the bed are defined in the longitudinal ends of the upper structural layer 10.

The lower structural layer 8 is also formed of sheet polypropylene and is rotary die cut with a repeating pattern of structural elements 20, which are substantially the same as those in the upper structural layer and will be described in detail below. Each structural elements 20 in the lower structural layer 8 corresponds in position to a structural element

25 20 in the upper structural layer 10. However, in the lower structural layer 8, the rows of structural elements 20 are not separated by slits, so that the rows of structural elements 20 are joined to each other for maximum integrity and stability of the lower structural layer 8. The carrying handles 6 of the bed are defined in the longitudinal ends of the lower structural layer 10.

Between the lower structural layer 8 and the upper structural layer 10, a system of pull cords 24 is provided for erecting the bed. A respective pull cord 24 is provided for each row of structural elements 20 and the pull cords 24 are arranged into groups of five

corresponding to each folding panel. The group of five pull cords 24 is connected to a longitudinal bar 26 at each transverse end of the pull cords 24 and each bar 26 is provided with a pull strap 28 which projects from a rebate 30 defined in the edges of the lower and upper structural layers 8, 10. The pull cords 24 are provided with lugs 32 which are fixed 5 in position on the pull cords 24 and engage with the structural elements 20 during erection in a manner that will be described in more detail below. Each structural element 20 is also provided with a piece of woven elastic 34. In Figure 3, for reasons of clarity, the elastic 34 and pull cords 24 are shown for only five of the structural elements 20.

10 Figure 3A shows the configuration of a structural element 20 of the upper structural layer 10. As mentioned above, the structural element 20 is roller die-cut from sheet polypropylene. The structural element 20 comprises a first strut member 36 which is connected to the upper structural layer 10 at its proximal end by a first strut hinge 38 formed by scoring the polypropylene sheet. At its distal end, the first strut member 36 is 15 provided with a first tab 40 connected to the first strut member 36 by a first tab hinge 42, also formed by scoring the polypropylene sheet. The first tab 40 has two holes defined therein for connecting the first tab 40 to a corresponding first tab of the lower structural layer 8.

20 A second strut member 44 is defined, substantially in a U-shape, around the first strut member 36 with the limbs of the U-shaped second strut member 44 connected to the upper structural layer 10 at their distal ends by respective second strut hinges 46 formed by scoring the polypropylene sheet. At the base of the U-shape, the second strut member 44 is provided with a second tab 48 connected to the second strut member 44 by a second 25 tab hinge 50, also formed by scoring the polypropylene sheet. The second tab 48 has three holes defined therein for connecting the second tab 48 to a corresponding second tab of the lower structural layer 8.

The strut hinges and tab hinges are live hinges that may be formed by moulding and die 30 cutting, as well as scoring.

Thus, the first strut member 36 is formed by cuts through the polypropylene sheet which defines three sides of the first strut member 36. Similarly, the second strut member 44 is

formed by cuts through the polypropylene sheet which define the inside and outside of the U-shape of the second strut member 44.

The structural elements 20 of the lower structural layer 8 are substantially the same as 5 those of the upper structural layer 10. However, in the lower structural layer 8, a cord hole 52 is defined in the first strut member 36 to receive the pull cord 24.

The bed is assembled by passing the pull cords 24 through the cord holes 52 of each structural element 20 of the lower structural layer 8 and fixing the lugs 32 in position on 10 the pull cords 24 so that one lug 32 is on each side of the cord hole of each structural element 20. The pull cords 24 are then connected to the bars 26 and pull straps 28 so that the loops of the pull straps 28 project from the recesses 30 in the edge of the lower structural layer 8, as shown in Figure 2. The upper structural layer 10 is then placed in position on top of the lower structural layer 8 and the longitudinal edges of the two 15 structural layers 8, 10 are bonded together, except at the recesses 30 for the pull straps 28. In addition, the transverse edges of the carry handles 6 of each layer are also bonded together.

With the two structural layers 8, 10 bonded together, their structural elements 20 lie on 20 top each other in alignment with their respective strut members 36, 44 and respective tabs 40, 48 in substantially exact superposition. One end of each piece of elastic 34 is located between the first tab 40 of each structural element 20 of the lower structural layer 8 and the first tab 40 of each structural element 20 of the upper structural layer 10 and is stitched in position using the two holes in the tabs 40, thereby connecting the two first 25 tabs 40. Similarly, the other end of each piece of elastic 34 is located between the second tab 48 of each structural element 20 of the lower structural layer 8 and the second tab 48 of each structural element 20 of the upper structural layer 10 and is stitched in position using the three holes in the tabs 48, thereby connecting the two second tabs 48. In this way, all of the first strut members 36 of the lower structural layer 8 are connected to 30 corresponding first strut members 36 of the upper structural layer 10 and all of the second strut members 48 of the lower structural layer 8 are connected to corresponding first strut members 48 of the upper structural layer 10.

The top layer 12 is bonded to the upper structural layer 10. The bonds between the top layer 12 and the upper structural layer 10 are only formed in the regions of the upper structural layer 10 that do not form the strut members 36, 44 and the tabs 40, 48, so that the strut members 36, 44 and the tabs 40, 48 are free to move away from the top layer 12.

5 The cover layer 14 is then fixed over the top layer 12.

The bed is erected by pulling each of the pull straps 28 in turn in the direction indicated by arrow D in Figure 4. When the pull straps 28 are pulled, the pull cords 26 move through the cord holes 52 of the lower first strut members 36 until the left-most (in Figure 10 4) lug 32 of each pair of lugs engages with the first strut member 36, because it is too large to pass through the cord hole 52. Further pulling of the pull strap 28 urges the lower first strut member 36 in the direction of the arrow D by the action of the lug 32 on the lower first strut member 36, so that the lower first strut member 36 rotates (clockwise in Figure 4) about the lower first strut hinge 38. The lower first strut member 36 also urges 15 the upper first strut member 36, to which it is connected at the first tabs 40, in the direction of the arrow D, so that the upper first strut member 36 rotates (anticlockwise in Figure 4) about the upper first strut hinge 38. The movement of the first strut members 36 pushes the upper structural layer 10 away from the lower structural layer 8 in a scissor action as the angle between the lower and upper first strut members 36 increases. The 20 connection between the longitudinal edges of the upper and lower structural layers 8, 10 and the flexural resilience of their polypropylene material acts to resist the pushing apart of the upper and lower structural layers 8, 10. Consequently, as soon as the first strut members 36 have passed the point at which they form a straight line perpendicular to the upper and lower structural layers 8, 10, the resistive force from the pushing apart of the 25 upper and lower structural layers 8, 10 acts to snap the first strut members 36 into the position shown in Figures 4 and 5.

In the position of Figures 4 and 5, the first strut members 36 form a strut between the upper structural layer 10 and the lower structural layer 8 that is hinged in the middle by 30 the first tab hinges 42 and at each end by the first strut hinges 38. The restorative force caused by the upper and lower structural layers 8, 10 attempting to return to a flat condition acts to push the ends of the strut (the first strut hinges 38) towards each other. Similarly, in this position, the second strut members 44 form a strut between the upper

structural layer 10 and the lower structural layer 8 that is hinged in the middle by the second tab hinges 50 and at each end by the second strut hinges 46. Again, the restorative force caused by the upper and lower structural layers 8, 10 attempting to return to a flat condition acts to push the ends of this strut (the second strut hinges 46) towards each 5 other. As the first and second strut hinges 38, 46 are pushed towards each other by the action of the upper and lower structural layers 8, 10, scissor action causes the first and second tab hinges 42, 50 (and the first and second tabs 40, 48) to move away from each other. However, the first tabs 40 are connected to the second tabs 48 by the elastic 34, which has a length such that it is taut in the position of Figures 4 and 5. Thus, the 10 extension of the elastic 34 counteracts the restorative force caused by the upper and lower structural layers 8, 10 attempting to return to a flat condition by preventing the first and second tabs 40, 48 from moving apart.

In this position, the structure of the bed is in equilibrium and forms a stable three-15 dimensional structure. A single structural element 20 in this position is shown in Figure 6A. As illustrated in Figure 6B, if additional downward force is applied to the upper structural layer 10, the scissor action of the first and second struts stretches the elastic 34 further, which resists the collapse of the structure. In this way, the structural elements 20 of the bed can be resiliently compressed from above, just like bed springs, to provide a 20 comfortable sleeping surface. Furthermore, as explained above, the rows of structural elements can move independently of each other because of the slits 16, 22 in the upper structural layer 10 and the top layer 12. This provides further enhanced comfort.

To collapse the bed, the pull straps 28 at the opposite side of the bed are pulled, in turn, in 25 the opposite direction to the arrow D in Figure 4. When the pull straps 28 are pulled, the pull cords 26 move through the cord holes 52 of the lower first strut members 36 until the right-most (in Figure 4) lug 32 of each pair of lugs engages with the first strut member 36, because it is too large to pass through the cord hole 52. Further pulling of the pull strap 28 urges the lower first strut member 36 in the opposite direction to the arrow D by the 30 action of the lug 32 on the lower first strut member 36, so that the lower first strut member 36 rotates (anticlockwise in Figure 4) about the lower first strut hinge 38. The lower first strut member 36 also urges the upper first strut member 36, to which it is connected at the first tabs 40, in the opposite direction to the arrow D, so that the upper

first strut member 36 rotates (clockwise in Figure 4) about the upper first strut hinge 38. The movement of the first strut members 36 pushes the upper structural layer 10 away from the lower structural layer 8 in a scissor action as the angle between the lower and upper first strut members 36 increases. Again, as soon as the first strut members 36 have 5 passed the point at which they form a straight line perpendicular to the upper and lower structural layers 8, 10, the resistive force from the pushing apart of the upper and lower structural layers 8, 10 acts to snap the first strut members 36 back into their flat position, as shown in Figures 6C and 6D.

10 Although an embodiment of the invention has been described by reference to the accompanying drawings, this should not be considered as limiting the scope of the invention as defined in the attached claims. It will be apparent to those skilled in the art that variations of the construction and materials of the invention are possible without departing from the scope of the invention. For example, it is not necessary for the tabs to 15 be connected by stitching. Other connection methods, such as for example riveting could also be used. Similarly, riveting could also be used to connect the edges of the lower and upper structural layers. Furthermore, the exact geometry of the structural elements may vary without departing from the scope of the invention.

20 In summary, a collapsible structure for a folding bed has a first panel and a second panel arranged in facing relation to the first panel. The panels are biased towards each other by the connection of their peripheral edges. A first support member is connected by a hinge to the first panel and by another hinge to the second panel. The first support member has a first main hinge between its ends, such that movement of the first panel towards the 25 second panel causes the first support member to fold about the first main hinge. A second support member is similarly configured between the first panel and the second panel. An elastic member is connected between the first and second support members to resist relative movement of the first and second support members in opposite directions. In this way, the elastic member resists the biasing of the first panel and the second panel towards 30 each other when the support members are folded in opposite directions. The first panel can be collapsed towards the second panel by folding the support members in the same direction. The structure provides a lightweight temporary bed that is easily erectable.