A bed base structure

Abstract: A bed base structure (2) for an adjustable bed (1) comprises plural parallel support strips (8); each of the support strips (8) is sequentially connected to an adjacent strip (8) to allow bending; and each of the strips (8) has a tongue (9) extending along one edge and a groove (9) in the opposite edge to allow interengagement of adjacent strips (8) by loosely engaging the tongue (9) of one strip into the groove (10) in the other. by providing a restricted slot opening (12) and an enlarged head (11) on the tongue (9) adjacent strips (8) hold themselves together once interengaged.

Description: The present invention relates to a bed base structure which can be bent to a proper curvature while allowing a user to continue feeling relaxed even though the bed base is partially raised. Many recent beds are equipped with a bed base lifting or adjusting mechanism, and various mechanisms are available. An ordinary adjustable bed base has a back portion simply connected to a central portion, which in turn is simply connected to a leg portion. When the back portion is raised, the joint between the back portion and the central portion acts as a pivot, (i.e forming an actual fulcrum), while when the leg portion is raised, the joint between the waist and leg portions also acts as a pivot. Therefore, as the back portion is raised forming an angle, the angular space between the back and central portions near the joint is narrowed, and unless the angle fits the body of the user in the bed, the waist, abdomen, and underside of the user's legs are uncomfortably pressed by the mattress. The present invention offers a solution to the above problem and seeks to provide a bed base structure which can be adjusted to adopt appropriate curves to provide a smooth curvature at the bent portions of the bed so as to minimize any displeasing pressure points for the user. Other bed base structures are known. For example FR 2608420 described a bed base comprising a plurality of interconnected slats which are held together by tongue and groove couplings allowing the slats to be separated from one another for transport or storage purposes. This structure, however, is aimed at providing a rigid, flat, substantially continuous support surface. According to the present invention there is provided a bed base structure for an adjustable bed in which at least a portion thereof comprises a plurality of elongate support strips connected together along opposite parallel edges thereof, each strip having an elongate groove in one face and an elongate tongue projecting from the opposite face with the relative dimensions of the tongue and the groove being such that two adjacent such strips can be held together by loose inter engagement of the tongue of one strip with the groove of the other characterised in that the relative shapes and dimensions of the tongues and grooves are such as to allow relative turning of one strip in either directional sense, about an axis parallel to its length, with respect to the other strip up to a maximum determined by the relative dimensions of the tongue and the groove, whereby to allow the bed base to be adjusted to include curved portions thereof for supporting convexly or concavely curved parts of the body of a user. The present invention also provides a bed base structure in which the tongues and the grooves are so formed as to allow the linked strips to be movable transverse their length allowing the length of the bed in the longitudinal direction to be adjusted. When the bed base structure is raised at the back and knee portions, the strips are raised forming a gentle curve. Since the strips have their tongues loosely engaged with the grooves of the adjacent support strips, the strips can lie at an angle to one another about their respective longitudinal axes. Therefore, if the shape of the tongues and slots or their dimensions are changed the maximum bending angle can be varied, and if the number of the strips is changed, the length of the curved section of the bed base can be varied. Preferably each groove has a restricted opening slot along its length which is narrower than the width of the main part of the groove, and each tongue has an enlarged head portion which is wider than the main part of the tongue, the said restricted opening slot being narrower than the said enlarged head of the tongue such that a tongue within a groove is held trapped loosely within the groove against removal through the said restricted opening slot. In the preferred embodiment the relative dimensions of the said tongue and the said groove are such as to allow relative movement between adjacent interconnected strips parallel to the depth of the groove, whereby to allow adjustment in the length of the bed base structure. Figure 1 is a side view of a bed having a bed base structure formed as an embodiment of the present invention; Figure 2 is an enlarged sectional view showing the support strips at a bendable portion of the bed base structure of Figure 1; Figure 3 is a perspective view of a support strip of the embodiment of Figures 1 and 2; Figure 4 is an enlarged sectional view showing another form of of the support strips; Figure 5 is an illustration showing a further embodiment where the entire bed base structure is covered with a flexible sheet; Figure 6 is an illustration showing a further embodiment where a flexible sheet is laid on the upper surface of the bed base structure; and Figure 7 is an illustration showing an embodiment where a mattress is caught in the gaps of the bed base structure. The bed base structure of the present invention is described below with reference to the attached drawings. Figure 1 shows a bed 1 having a bed base 2 formed as an embodiment of the present invention. The bed 1 can be raised at the back and knee portions by an electric actuator 3 provided below the bed base 2. The actuator 3 is provided with 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 bed base 2 on the underside at the back portion, through rollers 6, and the knee raising arms 5 contact the underside of the bed base 2 at the portion near the user's knees through rollers. In this bed 1, the bed base 2 has a plurality of substantially rigid transverse support strips 8 connected at the bendable portion between the back and central portions of the bed base 2 and at the bendable portion corresponding to the user's knees. Each of the support strips 8 has a tongue 9 projecting from one face and an elongate groove 10 formed in the opposite face. The groove of each support strip is engaged with the tongue of the adjacent support strip. Each of the tongues 9 has an enlarged head 11 in this embodiment formed as a T-Section and each of the corresponding grooves 10 has a restricted opening slot 12. The bottom strips 8 may be molded and may be either hollow or solid. They may be made of wood or any other suitable material. In the bed 1 with the above bed base structure, if the actuator 3 moves so as to raise a part of the base 2, the plural support strips 8 are raised to form a gentle curve. Since the support strips 8 have their tongues 9 loosely engaged in the grooves 10 of the adjacent strips 8, when the strips 8 are raised, they are able to be inclined to the adjacent strips 8 (see Figure 2). When the bed base structure is raised at both the back and knee portions the plural support strips 8 at the bendable portions form respective gentle curves. As a result, the user's waist, abdomen, and the underside of the user's legs are not comfortably pressed by the mattress 13. The support strips 8 can all be standard size and are of simple structure. Therefore, they can be easily mass-produced which is advantageous in view of manufacturing costs. To connect the support strips 8 together the tongue 9 of one of the strips 8 is slid, from one end, into the groove 10 of another strip 8. In this way, a predetermined number of the strips 8 of the bed base can be connected together to form the bendable portions of the bed base. If the shape or size of the tongues 9 and the grooves 10 are changed, the maximum curvature at a bend can be adjusted, and if the number of strips is changed, the overall length of the bed base can be adjusted. Further, if one of the bottom strips 8 becomes broken during use, only the broken strip 8 need be changed to allow for easy maintenance. The strips 8 can also be formed as shown in Figure 4. In this case the tongues are longer than in the embodiment of Figure 2 and the grooves 10 are deeper. The bottom bed base structure having the strips 8 can not only be bent to a curve but also adjusted in length in the longitudinal direction of the bed. The critical condition to allow much longitudinal adjustment is that the depth of the groove must be greater then the thickness or "height" of the enlargement of the tongue by which it is retained within the restriction (in this embodiment the T-Shape head 11), and the height of the tongue 9 must be greater than the thickness of the material defining the restrictions at the entrance slot 12 of the groove 10. In the present invention, when the bed base structure is bent, a mattress 13 is placed on the bed base structure might be caught in the gaps 16 formed between adjacent strips (see Fig. 7). To prevent this, the entire bed base may be covered with a flexible sheet 14 (see Fig.5) or a flexible sheet 14 may be attached to the upper surface of the bed base structure (see Fig.6) The symbol 15 in Fig.6 identifies means for fixing or attaching the flexible sheet 14 to the bed base structure. When the bed base structures of Figure 2 and Figure 4 are bent, the gaps 16 formed on the upper side are pinched together. It may also happen that dust and dirt are collected in the gaps 16. However, if a flexible sheet 14 is provided, the accumulation of dust can be reduced or prevented. A flexible sheet 14 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 has the following advantages: Since a plurality of strips of the same form are connected to allow bending, the bed can have a bed base structure which can be raised at the back and knee portions without causing any uncomfortable pressure. Since the strips are all the same shape, they can be easily mass-produced with advantageous manufacturing costs. By choosing the shape and proportions of the tongues and grooves in the support strips it is possible to determine the maximum curvature which the bed can adopt, and the length of the bed base can be made adjustable by arranging for the length of the tongues and the depths of the grooves to be such that, relative movement of interconnected strips parallel to the length of the bed base can take place.

Claims: A bed base structure for an adjustable bed in which at least a portion thereof comprises a plurality of elongate support strips (8) connected together along opposite parallel edges thereof, each strip (8) having an elongate groove (10) in one face and an elongate tongue (9) projecting from the opposite face with the relative dimensions of the tongue (9) and the groove (10) being such that two adjacent such strips (8) can be held together by loose interengagement of the tongue (9) of one strip with the groove (10) of the other characterised in that the relative shapes and dimensions of the tongues (9) and grooves (10) are such as to allow relative turning of one strip (8) in either directional sense, about an axis parallel to its length, with respect to the other strip (8) up to a maximum determined by the relative dimensions of the tongue (9) and the groove (10), whereby to allow the bed base to be adjusted to include curved portions thereof for supporting convexly or concavely curved parts of the body of a user. A bed base structure according to claim 1, characterised in that each groove (10) has a restricted opening slot (12) along its length which is narrower than the width of the main part of the groove (10), and each tongue (9) has an enlarged head portion (11) which is wider than the main part of the tongue (9), the said restricted opening slot (12) being narrower than the said enlarged head (11) of the tongue such that a tongue (9) within a groove (10) is held trapped loosely within the groove (10) against removal through the said restricted opening slot (12). A bed base structure according to Claim 2, characterised in that the relative dimensions of the said tongue (9) and the said groove (10) are such as to allow relative movement between adjacent interconnected strips (8) parallel to the depth of the groove (9), whereby to allow adjustment in the length of the bed base structure (2). A bed base structure according to any preceding Claim, further comprising a flexible sheet (14) covering at least one surface of the said elongate strips (8). A bed base structure according to any preceding Claim, characterised in that the said strips (8) have four faces and each strip has a tongue (9) formed on one face and a groove (10) formed in an opposite face, and wherein said strips (8) are sequentially connected and secured by locking engagement of said tongue (9) of one strip with said groove (10) of an adjacent strip, and wherein said tongue (9) is sufficiently smaller than said groove (10) as to facilitate movement of the tongue (9) in said groove (10) and flexure between each strip (8) such that when any section of the bed is raised a gentle curve is formed.

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