Patent Publication Number: US-6910236-B2

Title: Mattress leg rest section for an articulatable bed convertible to a chair position

Description:
TECHNICAL FIELD 
   The present invention relates to a mattress leg rest section for use with an articulatable bed which is convertible to a chair position and wherein the mattress leg rest section is made of compressible material secured to a retractable framework. 
   BACKGROUND ART 
   It is known to construct articulatable beds which can be convertible to a chair position and this is particularly so with respect to hospital beds. For example, such a bed is described in U.S. Pat. No. 6,427,264. Reference is also made to U.S. Pat. No. 6,141,806 which relates to a bariatric bed and in both these patents the leg section of the bed is compressible by removing air from an extendible cushion. When the bed is moved to a seating position it is necessary to compress the leg rest section and this is achieved by providing an inflatable bag which is restrained and which is extendible by pumping air in the bag and compressible by releasing air from the bag. Such extendible leg rest sections have not functioned adequately and are problematic. For example, they require an air compressor and control devices for admitting and releasing air from the inflatable bag. This equipment is costly and requires extra space for mounting under the bed. It is also noisy. Also, the bag does not provide a solid support surface as any load on the bag displaces air and makes the support surface unstable. These bags can also be punctured and they don&#39;t offer safety features which are paramount with hospital beds. These bags also often need to be adjusted by an operator. With this type of bed construction it is not possible to provide a mattress wherein all the mattress sections are located in a single fabric envelope, due to the compression of the inflatable bag when air is released. 
   SUMMARY OF INVENTION 
   It is a feature of the present invention to provide a mattress leg rest section for use with an articulated bed convertible to a chair position and which substantially overcomes the above-mentioned disadvantages of the prior art. 
   It is a further feature of the present invention to provide a mattress leg rest section which is compressible and which offers a rigid support surface when in an extended position or a compressed position and wherein all of the mattress sections can be contained in a single envelope. 
   Another feature of the present invention is to provide a compressible mattress formed from a high density soft foam piece material having an undulated surface section which is compressible and wherein the foam piece is restrained during compression and decompression. 
   According to the above features, from a broad aspect, the present invention provides a mattress leg rest section for use with an articulated bed convertible to a chair position. The mattress leg section comprises at least a compressible section formed of compressible material and having an undulated surface section defining peaks and valleys formations dimensioned such as to be compressed by compressible interconnecting means to cause the peaks formations to be displaced closer to one another within the valleys formations to shorten the mattress leg rest section. 
   According to a still further broad aspect of the present invention there is provided an articulated bed convertible to a chair position. The bed comprises a mattress formed of sections including a leg rest section. The mattress sections are secured respective to support frames. Articulating linkage means is provided to articulate the support frames. The leg rest section of the mattress is secured to a retractable support frame. Means is provided to support the support frames elevated from a floor surface. The mattress has at least a compressible section thereof formed of compressible material. Compressible interconnecting means is provided to compress the compressible material to shorten the length of the compressible section. Restraining means is provided to restrain the compressible material as it is compressed and decompressed when the support frames are displaced from a horizontal position to an articulated chair position and vice versa. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
       FIG. 1  is an example of an articulated bed support frame to which the mattress leg rest section of the present invention is secured; 
       FIG. 2  is a side view of  FIG. 1 ; 
       FIG. 3  is a fragmented plan view showing the retractable leg rest support frame in a retracted position whereas in  FIG. 1  it is illustrated in an extended position; 
       FIG. 4  is a perspective view showing the mattress sections incorporating the mattress leg rest section of the present invention; 
       FIG. 5  is a side view showing the mattress sections of  FIG. 4  secured to articulatable support frames; 
       FIG. 6  is a side view showing the articulated bed disposed in a chair position; 
       FIG. 7  is a perspective view illustrating the construction of the compressible foam piece section incorporated in the leg rest section of the mattress; 
       FIG. 8  is a plan view, partly fragmented illustrating the construction of the interconnecting telescoping members retained captive in the soft foam piece in a solid foam section under the undulated surface section thereof; 
       FIG. 9  is a fragmented section view showing the interconnection of the telescoping tubes with a bushing interposed between the tubes, and 
       FIG. 10  is a fragmented cross-section view illustrating the construction of the restraining means which is constituted by a composite fabric material tube which is glued in elongated cavities formed along the underside of the compressible foam piece section. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring now to the drawings and more particularly to  FIGS. 1  to  3  there will be described the construction and operation of an articulatable bed support frame which is known in the prior art and to which the compressible mattress leg rest section of the present invention is secured. However, these support frames may be constructed differently provided they have a retractable leg rest section to which the compressible mattress leg rest section of the present invention can be secured to. 
   As hereinshown the articulated support frame  10  comprises a backrest support frame  11 , a seat rest support frame  12 , and a retractable leg rest support frame  13 . These support frames  11 ,  12  and  13  are interconnected together through linkages  14 , as better shown in FIG.  2  and to an attachment frame  15  which is in turn secured to an elevating frame  16  hereinshown in phantom line and having floor supports or casters  17  to support the bed on a floor support surface  18 . 
   The retractable leg rest support frame  13  has a sliding frame section  19  which slides over a stationary frame section  20  to adjust the length of the leg rest support frame  13 . It is necessary to retract the sliding frame section  19  over the stationary frame section  20  to shorten the length of the retractable leg rest support frame when the support frame sections  11 ,  12  and  13  are articulated to a seating position as shown in FIG.  6 . However, when the retractable leg rest section  13  is retracted to the position of  FIG. 6 , it is necessary to retract the sliding frame section  19  to shorten the length of the retractable leg rest section  13  in order for a patient initially lying on the bed to be brought to a sitting position and being able to disembark the chair if necessary. 
   As shown in  FIGS. 1 and 3  the retractable leg rest support frame is provided with attachments  21  for fastening a compressible mattress thereto. 
   Referring now to  FIG. 4  there is illustrated the mattress sections which are securable to the frame sections. As hereinshown the mattress sections comprises a backrest mattress section  23 , a seat rest mattress section  24  and the leg rest mattress section  25  of the present invention. These sections are secured to the support frames  11 ,  12  and  13  as illustrated in  FIG. 5  with the backrest mattress section  23  secured to the backrest support frame  11 , the seat rest mattress section  24  secured to the seat rest support frame  12  and the compressible leg rest mattress section  25  secured to the retractable support frame  13 . 
   As shown in  FIGS. 5 and 6  the support frame sections are articulated by the linkages  14  and pivot connections such as identified by reference numerals  26  and guide track  27 . A piston  28  which is hydraulically or pneumatically operated causes the frame sections to be displaced to desired positions. Similarly, the sliding frame section  19  of the retractable leg rest support frame  13  can be displaced by pneumatic, hydraulic or mechanical means not shown. The bed support frames can also be lowered with respect to the floor support surface  18  by hydraulic, pneumatic, electric or mechanical means not shown but obvious to a person skilled in the art. 
   With reference now to  FIGS. 7  to  10  there will be described the construction of the mattress leg rest section of the present invention. As shown in  FIG. 7  the leg rest mattress section  25  is comprised of a high density soft foam material block  26  having an undulated surface section  27  defining peaks formations  28  separated by valleys formations  29 . These peaks and valleys formations are dimensioned such that when the block is compressed from opposed retractable ends  30  and  34 , the peaks formations  28  will be displaced closer to one another within the valleys formations whereby to compress the soft foam block  26  between its ends to shorten the block. As hereinshown the peaks and valleys are disposed in an alternating manner. 
   In order to compress the soft foam block there is provided compressible interconnecting means in the form of a pair of rigid connecting members  33  and  34  which are interconnected together by interconnecting telescoping means in the form of telescoping tubes  35  and  36 . The tube  36  slides into tube  35  and the tubes are displaceable in translation with respect to one another to compress and decompress the soft foam block  30 . As hereinshown the tubes are aluminum tubes and are separated by a nylon tubular bushing  37  as shown in  FIG. 9  to prevent friction and wear of the tubes. There are 3 hollow telescoping aluminum tubes  35  as shown in  FIG. 8  but it is to be understood that there could be 2 or more than 3 of these tubes. These telescoping tubes are connected to the rigid connecting members  33  and  34  by suitable means such as fasteners or welding attachments  38  and the tubes are disposed between transverse rigid connecting members as hereinshown. The rigid connecting members  33  and  34  are retained parallel to one another and have attachment means in the form of through bores  39  for connecting to the attachments  21  of the sliding frame section  19  and stationary frame section  20  of the retractable leg rest support frame  13 . Fasteners, not shown, are used to interconnect the connecting members  33  to their respective attachments  21 . 
   It is pointed out that the rigid connecting members  33  and  34  are secured to the connectable ends  31  and  30  respectively and this securement can be achieved in many ways. For example as shown in  FIG. 8  opposed ends of the foam block  26  may be glued, such as shown at  40 , to a flat top surface of these rigid connecting members. On the other hand, these rigid connecting members may be provided with a transverse vertical connecting flange  42  to abut the end walls  41  of the block and that could be glued to the lower portion of the end wall. Longitudinal channels or cavities  46  are also formed in the solid bottom section  45  of the block whereby to accommodate the telescoping tubes  35  therein. These telescoping tubes are retained captive in a respective one of the cavities  46  and the reason for this is to prevent buckling of the foam block when compressed. It is important that when the foam block is compressed that it is maintained in a substantially common horizontal plane in order to cause the peaks formations to compress against one another and deform, with the valleys allowing for the maximum desired compression, which is dependent on the length of displacement of the sliding frame section  19  of the retractable leg rest support frame  13 . It is also pointed out that the connectable ends  30  at opposed ends of the soft foam block  26  may have solid sections of the high density soft foam. 
   With reference now to  FIG. 10  there will be described the restraining means that retains the compressible material in a substantially uniform plane as it is compressed and decompressed. This restraining means is constituted by a fabric material tube  50  which is hereinshown as a double layer material tube having an outer neoprene layer  51  and an inner nylon layer  52  which are secured together such as by gluing or stitching to form the elongated material tube  50 . The reason for the outer neoprene material is that such material has excellent adherence properties when glued to another surface. As hereinshown this tubular material is glued inside the channels  46  by the application of glue spots  47  within the channel. Glue spots may be provided under the peaks formations  28  and at the ends and the glue must permit the material tube  50  to also compress. When the fabric tube is glued the telescoping tubes are disposed therein whereby the tube  50  can retain its shape during the time the glue sets. Of course there may be sufficient glue to fill the interstices  53  within the channel under the peaks formations. The glue also needs to have flexibility during compression and decompression of the foam block  26 . Therefore, it can be seen that the foam block is attached to the telescoping tubes  35  and the frames  33  and  34  through the fabric sleeve. The inner nylon sleeve  52  provides excellent frictional characteristics with the outer surface  35 ′ of the outer tube  35 . 
   As shown in  FIG. 6  the leg rest mattress section  25  as well as the backrest section  23  and seat rest section  24  are all disposed within a single envelope or bed sheet  55  and during compression this envelope is squeezed within the valleys formations  29  of the leg rest mattress section  25 . When decompressing, it is released. Accordingly, it is not necessary to have different envelopes for each of the mattress sections. 
   Although the articulated bed as hereinshown and described is primarily for hospital use it is also pointed out that the mattress leg support section of the present invention can be used on articulated beds not intended for hospital patients. For example, it could be secured to wheelchair structure of the type as shown in aforementioned U.S. Pat. No. 6,141,806 or other chair/bed designs and wherein a bed ridden person can convert his bed to a chair and displace himself on wheels which are actuated by the hands of the patient. The bed can also be disposed at various intermediate positions, from a seated position to a horizontal bed position, for purposes of relaxation or for any other purpose. Accordingly, it is not intended to limit the use of the mattress leg rest section as herein described. 
   It is within the ambit of the present invention to cover any obvious modifications of the embodiments described herein, provided such modifications fall within the scope of the appended claims.