A bed base structure

Abstract: The present invention provides a bed base structure (2) for an adjustable bed (1), that is one having a mechanism (3) for raising a back and/or a leg portion to an inclined position. The hinge portions of the structure are formed by a plurality of parallel transverse support strips (8), each strip having coupling groves (10), located in opposing faces thereof. The strips (8) are sequentially connected by coupling members (9), each coupling member (9) having portions (11) corresponding in shape to the coupling grooves along opposite edges, which can be incorporated as components of the bed base structure.

Description: The present invention relates to a bed base structure for an adjustable bed which can be bent to a smooth curve allowing a user to continue feeling relaxed even though bed base is partially raised. Many recently manufactured beds are equipped with an adjustment mechanism, and various mechanisms are available. One known adjustable bed has a back portion simply connected by a hinge to a central portion. The central portion and a leg portion are also simply connected by a hinge. When the back portion is raised the junction between the back and central portions acts as a pivot and likewise, when the leg portion is raised, the junction between the central portion and the leg portion also acts as a pivot. As the back portion is raised, the angular space between the back and central portions near the junction becomes smaller and unless the angle fits the body of the user in the bed, the waist, abdomen, and underside of the user's legs may be uncomfortably pressed by the mattress. The present invention seeks to provide a solution to the above problem by providing a bed base structure for a bed which can be bent in appropriate curves to provide gentle curvature at the bent portions of the bed so as to minimise any displeasing pressure points for the patient or user. According to the present invention there is provided a bed base structure for an adjustable bed, characterised in that it includes a support portion which can be flexed into a curve, comprising a plurality of transverse support strips each having coupling grooves formed in opposite faces thereof, adjacent pairs of support strips being interconnected by respective coupling members having elongate ribs engaged in respective said grooves in such a way as to hold the said adjacent support strips together while allowing relative turning movement thereof about an axis parallel to the length of the strip. Each said groove may have a narrow elongate slot opening defined by opposite lips which retain the rib of the connector member against escape from the groove. The said elongate ribs of each coupling member may have a curved bulbous form in cross section, in which case the said grooves in the support strips preferably have a correspondingly curved arcuate cross section whereby to allow the coupling member to turn smoothly in the groove through a limited angle about an axis parallel to the length of the groove. Alternatively, however, the said grooves in the said support strips may have a generally rectangular cross section, in which case the said ribs of the said coupling members may be generally T-shaped flanges adapted to be engaged within the grooves and to be retained by the lips defining the said narrow slot opening. Regardless of the form of the grooves and/or the ribs on the coupling members, the depth of the groove may be such as to allow relative movement of two interconnected support strips towards or away from one another whereby to allow variation in the length of the said bed base structure. Features allowing such adjustment include the thickness of the lips defining the narrow entrance slot to the grooves, the width of the connector member itself, the depth of the groove within which the ribs are housed, and the thickness of the rib in the direction of the width of the connector member. The said coupling members may be made of an elastic or resilient material, or may be rigid. Likewise the support strips may be plastics material or wood, or even an extruded light alloy of a metal such as aluminium. All the support strips may be the same size as one another and all the coupling members may be the same size as one another. This simplifies and economises on manufacture. The coupling members may be made of a rigid or resilient plastics material, an elastomer or wood. At least one flexible sheet covering may extend over at least the bendable portions of the bed base structure defined by the transverse support strips, at least on one of the upper or lower surfaces thereof. Embodiments of the invention may have covering strips on both surfaces. The present invention also comprehends an adjustable bed incorporating a bed base structure according to the present invention and a mattress carried by the said base structure. One embodiment of the present invention will now be more particularly described, by way of example, with reference to accompanying drawings, in which Figure 1 is a side view of an adjustable bed having a bed base structure formed as an embodiment of the present invention; Figure 2 is an enlarged sectional view showing a bendable portion of the bed base structure shown in Figure 1; Figure 3 is a perspective view of a transverse support strip and coupling member suitable for use in the bendable portions of Figure 2; Figure 4 is an enlarged sectional view of two alternative forms of transverse strip and coupling members suitable for use in the embodiment of the invention shown in Figure 2; Figure 5 is a sectional view of the bendable portions of a further embodiment of the present invention; Figure 6 is a sectional view of another embodiment in which the bed base structure is covered with a flexible sheet; Figure 7 is sectional view of another embodiment, in which a flexible sheet is attached to the upper surface of the bed base structure; Figure 8 is a sectional view showing how a mattress may be trapped in the gaps between adjacent support strips of a bed base structure. Referring now to the drawings, a bed 1 has a plurality of transverse support strips 8 defining a bendable portion or junction, between a back portion and a central portion of a bed base structure 2, and between the central portion and a leg portion. In the embodiment illustrated in Figures 2 and 3 each of the transverse support strips 8 has a groove 10 formed in each of two opposite faces along the whole of the length of the strip. Each groove also has a curved arcuate form in cross section with a narrow entrance slot 20 defined by two opposite lips 21. Adjacent support strips 8 are linked by respective coupling members each in the form of a flat strip having two enlarged ribs or bulbous portions 11 along opposite edges. The bulbous portions 11 are fitted in the coupling grooves 10 of adjacent support strips 8 to connect them together and are trapped in the grooves 10 by the lips 21 defining the narrow entrance slot. The support strips 8 may be moulded plastics and may be either hollow or solid. They may also be made of wood. The coupling members 9 may be made of rigid or resilient material. As a result of using the above described support strips and coupling members at the bendable portions of the adjustable bed, the bed base does not cause displeasing pressure points on a user and can be flexed smoothly into a gently radi-ussed curve. If the back or leg portions of the bed base are raised the support strips form a gentle curve. The coupling members 9 for mutually connecting the support strips 8 are able to turn smoothly without any resistance in the coupling grooves allowing the support strips 8 to be raised to form predetermined angles with respect to one another. The maximum curvature can be varied by varying the width of the coupling members and the form of the coupling grooves (and thus the interval between adjacent support strips 8). The length of the curved portion can be varied by varying the number of support strips in the array. Although they may be rigid, if the coupling members 9 are made of an elastic or resilient material, the bed base can be bent more smoothly, and even if a heavy load is applied, the bed base remains resilient. Figure 1 shows an adjustable bed 1 having the bed base structure of the present invention. A back portion and a knee portion may be raised by an electric activator 3 provided below the base 2. The activator 3 has back-raising arms 4 for raising the back portion, and knee-raising arms 5 for raising the knee portion. The back-raising arms 4 contact the base 2 on the underside at a position corresponding to the back portion, through rollers 6, and the knee-raising arms contact the bottom 2 on the underside at a position near the knee joint of a user's legs, through rollers 7. In this bed 1, the bendable portion between the back and central portions of the base 2 and the bendable portion for raising the patient's legs are formed by respective arrays of parallel support strips 8 and coupling members 9 connecting the strips 8. Each of the support strips 8 has coupling grooves 10, in the form of circular arcs when viewed in cross section, located in the opposite faces of the strip 8 and extending in the longitudinal direction of the strip throughout its length. In the embodiment shown in Figures 2 and 3, each of the coupling members 9 has bulbous portions 11 corresponding to the coupling grooves, at opposite edges of the coupling member. The bulbous portions 11 are fitted into the coupling grooves 10 of the support strips 8 forming a sequential connection of the strips 8 and maintained by the lips 21 defining the narrow entrance slot 20. The strips 8 may be moulded plastics and may be hollow or solid. They may also be made of wood. The coupling members 9 may be made of an elastic or resilient material or may be rigid. To adjust the bed 1 with the above base structure, the activator 3 is started to partially raise the base 2 causing the support strips 8 to be raised, forming a gentle curve. The bulbous portions 11 along the edges of the respective coupling members 9 connecting the support strips 8 can slide smoothly within the grooves 10 without any resistance due to the curved shape of the circular arcs when viewed in cross section. The respective support strips 8 can thus turn in relation to one another up to a maximum predetermined angle against the adjacent support strip 8. If the coupling members 9 are made of an elastic or resilient material, the curve is formed more smoothly, and even when a heavy load is applied, the base remains resilient. Thus, when the bed base is raised at the back and knee portions, the support strips are raised to form a gentle curve. As a result the waist, the abdomen, and the underside of the user's or patient's legs at the bent portions are not uncomfortably pressed by the mattress. Further, since the support strips 8 and the coupling members 9 can be standardised and are simple in structure, they can be easily mass-produced with an attendant manufacturing cost advantage. To connect the support strips 8 together one of the bulbous portions 11 of a coupling member 9 is slid into the corresponding coupling groove 10 of a support strip 8 with the web of the coupling strip engaged in the narrow entrance slot 20 of the groove 10. Then, the other bulbous portion 11 of the coupling member 9 is slid into the corresponding coupling groove 10 of another strip 8. In this way, a predetermined number of strips 8 are sequentially connected to form the bendable portion of the bed base structure. If the width of the coupling members 9 and the form of the coupling grooves are changed, the shape of the bend can be adjusted. Likewise, if the number of strips 8 is changed, the length of the curve can be adjusted. Moreover, if one of the strips 8 or coupling members 9 becomes broken during use, the broken strip 8 or coupling member 9 only can be exchanged for easy maintenance. The strips 8 and coupling members 9 may also be formed as shown in Figure 5. In this embodiment, each of the strips 8 has rectangular coupling grooves 13 located in the opposite faces of the strip extending in the longitudinal direction thereof. Each groove has a narrow entrance slot 12 defined by opposite lips 22. Each of the coupling members 9 has two longitudinal ribs 14 at opposite longitudinal edges thereof which are trapped in the grooves 13 by the lips 22 defining the narrow entrance slots 12. The depth of the grooves 13, and thickness of the ribs 14 are such that, together with the overall width of the connector strip 9, the adjacent support strips 8 are relatively movable towards and away from one another so that the overall length of the bed base 1 can be varied. Further, if the coupling members 9 are made of an elastic or resilient material, the overall length of the bottom can be adjusted more flexibly with the bed base remaining resilient. In the present invention, when the bed base structure is bent, a mattress 15 placed on the bed base might be caught in the gaps 18 formed between adjacent support strips (see Figure 8). To prevent this, the entire bed base may be covered with a flexible sheet 16 (see Figure 6) or a flexible sheet 16 may be attached to the upper surface of the bed base structure (see Figure 7). The symbol 17 in Figure 7 shows means for fixing or attaching the flexible sheet 16 to the bed base structure. When the bed base structures in figure 2 and Figure 5 are bent, the gaps 18 formed on the upper side are pinched together. It may happen that dust and dirt may collect in the gaps 18. However, if a flexible sheet 16 is provided, the accumulation of dust can be reduced or prevented. A flexible sheet 16 is preferably provided to permit easier cleaning. Further, it also prevents anything from being caught in the gaps formed during bending which might impair the function of the bed base structure. As described above, the present invention offers the following advantages: Since support strips of the same form connected by coupling members are used to form the bendable portions of the bed base, this does not cause any feeling of displeasing pressure to a patient when the structure is raised at the back or knee positions. Since all of the support strips and all of the coupling members are of the same shape and form, they can be standardised so that they can be easily mass-produced, resulting in advantageous manufacturing economy. In embodiments in which the coupling members have bulbous ribs engaged with coupling grooves having an arcuate circular cross section, the flexing parts of the bed base can move very smoothly when adjustments are being made to the back or knee portions. The maximum curvature can be determined by the choice of shape and dimensions of the coupling grooves, the connector strip and its ribs. If the number of the support strips connected together is changed, the length of the bed base structure can be changed in the longitudinal direction. If the coupling members are made of an elastic or resilient material, the bed base can be bent more smoothly, and even if a load is applied, the bottom remains resilient. If a strip is broken during use, the broken strip can readily be changed allowing for easy maintenance. If a flexible sheet is used to cover the bed base structure, it is easier to clean and materials are prevented from impeding the function of the structure during bending.

Claims: A bed base structure (2) for an adjustable bed (1), characterised in that it includes a support portion which can be flexed into a curve, comprising a plurality of transverse support strips (8) each having coupling grooves (10) formed in opposite faces thereof, adjacent pairs of support strips (8) being interconnected by respective coupling members (9) having elongate ribs (11) engaged in respective said grooves (10) in such a way as to hold the said adjacent support strips (8) together while allowing relative turning movement thereof about an axis parallel to the length of the strip (8). A bed base structure (2) according to Claim 1, characterised in that each said groove (10) has a narrow elongate slot opening (20) defined by opposite lips (21) which retain the rib (11) of the connector member (9) against escape from the groove (10). A bed base structure (2) according to Claim 1 or Claim 2, characterised in that the said elongate ribs (11) of each coupling member (9) have a curved bulbous form in cross section and the said grooves (10) in the support strips (8) have a correspondingly curved arcuate cross section whereby to allow the coupling member to turn smoothly in the groove (10) through a limited angle about an axis parallel to the length of the groove. A bed base according to Claim 1 or Claim 2, characterised in that the said grooves (12) in the said support strips (8) have a generally rectangular cross section and the said ribs (14) of the said coupling members (9) are generally T-shape flanges adapted to be engaged within the grooves (12) and to be retained by the lips (22) defining the said narrow slot opening. A bed base according to any preceding Claim, characterised in that the depth of the grooves is such as to allow relative movement of two interconnected support strips (8) towards or away from one another whereby to allow variation in the length of the said bed base structure. A bed base structure according to any preceding Claim, characterised in that the said coupling members (9) are made of an elastic or resilient material. A bed base structure according to any preceding Claim, characterised in that all said support strips (8) and/or all said coupling members (9) are the same size as one another. A bed base structure according to any preceding Claim, characterised in that the said coupling members (9) are made of a rigid or resilient plastics material, an elastomer or wood. A bed base structure according to any preceding Claim, characterised in that there is provided at least one flexible sheet (16) covering at least the bendable portions defined by the transverse support strips (8) at least on one of the upper or lower surfaces thereof. An adjustable bed incorporating a bed base structure according to any preceding Claim and a mattress carried by the said bed base structure.

Inventors: SHIRAI KUNITO, SHIRAI, KUNITO
Applicants: PARAMOUNT BED KK, PARAMOUNT BED COMPANY LIMITED
Application year: 1993
Main classification: A47C23
IPC codes: A47C20, A47C31, A47C23, A61G7