Abstract:
A sofa bed is convertible to a bunk bed using front and rear links coacting with front and rear cylinders to lift a bunk frame from the sofa position, in which it is used for seating, to a bunk bed position where seat cushions are used on the bunk and a mattress is available for a lower bunk, the cylinders being lockable and a brace and latter are deployable and lockable to secure the bunk.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims priority on Provisional application Ser. No. 62/259,956 filed Nov. 26, 2015, having the same title and inventor as the present application and having attorney docket No. CU-72546. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The present invention relates generally to a furniture assembly, and more particularly, to a sofa bed convertible into a bunk bed having a mechanism being compact and particularly adaptable to placement in vehicles or dimensionally limited locations. 
         [0004]    BACKGROUND 
         [0005]    A sofa usually has a seating surface, a back surface, and arms, while a bunk bed has a plurality of sleeping surfaces oriented with at least a portion of a top sleeping surface vertically displaced above a lower sleeping surface. The convertible bunk bed stores the bed in the area above the seating surface. In the prior art EP2110054 (A1) “Mechanism for bunk beds and sofa-bed comprising this mechanism” appears to use curved links to enable a bunk bed to be moved vertically to a position above the lower bed. In the prior art CN202553068 (U) “Novel dual-use sofa” the arms of the sofa are pivoted so that the top bunk is inverted when the sofa is in the seating position and when rotated 180 degrees upwardly so that the frame inverts to present the opposite surface for sleeping. 
         [0006]    The former utilizes a mechanism of some complexity for ease of deployment, but lacks a desirable level of rigidity and support when in the bunk bed position. The latter requires a substantial range of motion for movement of significant mass in directions atypical to the user. 
         [0007]    In the prior art U.S. Pat. No. 405,495 “Foldable Bunk Bed Assembly” a hinged outer portion of a seat back converts to upper bunk but requires mounting on a wall or bulkhead. U.S. Pat. No. 7,360,261 “Sofa” hinges the seat back to the seat back frame pivoting upward to a bunk bed position. U.S. Pat. No. 4,592,101, “Sofa-bunk bed combination with pivotable cushion” pivots and elevates the seat back to be used as the top bunk. Published application CN202553068U “Novel dual-use sofa” has a hinged front and rear portion with overlapping platforms in which the front portion rotates forwardly and upwardly and inverts, the upper inverted platform forming the bunk bed and the lower platform forming the lower bed. Published application EP2110054 (A1) “Mechanism for bunk beds and sofa-bed comprising this mechanism” uses complex linkage to raise and invert a lower seat platform so that when inverted and fully raised it forms a top bed in a bunk bed. 
         [0008]    The present invention solves problems in the prior art described above. The sofa convertible to a bunk bed described herein provides a superior sleeping surfaces in a more compact footprint and range of motion, while additionally providing structure for mounting in vehicles and clearance for mounting such securement apparatus as seat belts and harness over that of the prior art sofa bunk beds. Links acting in combination with pneumatic cylinders or other telescoping struts provide mechanical advantage and locking for a trussile support mechanism. The frame design additionally incorporates guards and ladders in a unitary assemblage. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1  is a front elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position. 
           [0010]      FIG. 2  is a side elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position. 
           [0011]      FIG. 3  a perspective view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position. 
           [0012]      FIG. 4  is a front elevational view of an embodiment of the sofa convertible to a bunk bed in the sofa position. 
           [0013]      FIG. 5  is a side elevational view of an embodiment of the sofa convertible to a bunk bed in the sofa position. 
           [0014]      FIG. 6  is a top plan view of an embodiment of the sofa convertible to a bunk bed with the front guard undeployed. 
           [0015]      FIG. 7  is a perspective view of an embodiment of the sofa convertible to a bunk bed in the sofa position. 
           [0016]      FIG. 8  is a perspective view of an embodiment of the sofa convertible to a bunk bed in the mid-position. 
           [0017]      FIG. 9  is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the sofa position. 
           [0018]      FIG. 10  is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the mid-position. 
           [0019]      FIG. 11  is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position taken on line A-A of  FIG. 1 . 
           [0020]      FIG. 12  is a perspective view of an embodiment of the sofa with mattress and cushions shown. 
           [0021]      FIG. 13  is a perspective view of an embodiment of the sofa with mattress and cushions shown with the bunk configured for sleeping. 
           [0022]      FIG. 14  is a perspective view of an embodiment of the sofa back cushion.  FIG. 1  is a front elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position. 
           [0023]      FIG. 15  is a side elevational view of an embodiment of the sofa having a first alternative track and gas cylinder pivot location. 
           [0024]      FIG. 16  is a side elevational view of an embodiment of the sofa having a second alternative track and gas cylinder pivot location. 
           [0025]      FIG. 17  is a side elevational view of an embodiment of the sofa having a third alternative track and gas cylinder pivot location. 
           [0026]      FIG. 18  is a side elevational view of an embodiment of the sofa having a fourth alternative track and gas cylinder pivot location. 
       
    
    
       [0027]    Terms such as front, side, rear, left and right as may be used herein are relative terms referring to the sofa convertible to a bunk bed and are not limited to its mounting, installation or arrangement to any particular position or space in a room or vehicle or to which direction a person is oriented on the sofa or bed. Unless otherwise qualified left and right refer to the point of view of a person sitting on the sofa. 
       DETAILED DESCRIPTION 
       [0028]    Referring to the drawings, the sofa bed  10  of this invention is generally shown. The sofa bed  10  includes base frame assembly  12  with side frames  14  and  16  interconnected by rear transverse frame  18  and front transverse frame  20 . Side frames  14  and  16  may be formed of perimetrical frame members, solid plates  22 ,  24 , or a combination. Each plate  22 ,  24  is formed and arranged so as to have an angled, straight tracks or guide slots  26 ,  28 . 
         [0029]    Advantages to using solid sheet or plate could include the substantial elimination of components requiring assembly; the ability to be formed through automated manufacturing means such as laser cutting or other appropriate machining, and the elimination of braces between the tracks or guide slots  26 ,  28  which can be more easily maintained in position by the presence of the solid web between them. 
         [0030]    The upper bunk frame  30  is formed with a lower perimetrical frame  32  and a rear guardrail assembly  34 . On each side is a side guard  36 ,  38 . 
         [0031]    Upper bunk frame  30 , when deployed in the bunk bed position is primarily supported by right and left front links  40 ,  42  and right and left rear links  44 ,  46 . The right and left front links  40 ,  42  are dynamically actuated and statically fixed (when locked) by right and left front cylinders,  48 ,  50 . The right and left rear links  44 ,  46  are dynamically actuated and statically fixed (when locked) by right and left rear cylinders,  52 ,  54 . Cylinders  48 ,  50 ,  52 ,  54  are preferably pneumatic cylinders but equivalents such as hydraulic cylinders, or spring, screw or rack and pinion mechanisms could be used to perform the function of assisting in raising bunk bed frame  30  and maintaining it in the bunk bed position  56 . 
         [0032]    In the bunk bed position  56  ladder  58  is rotated to a vertical position and locked, front brace  60  is rotated to a vertical position and locked with locking mechanism  64 . Front guard  62  is rotated to a vertical position and locked with locking mechanism  64 . Extending upwardly from side frames  14  and  16  are tabs  66 ,  68 . These may be formed with frame members or plate or a combination. 
         [0033]    In an embodiment, here described with reference to left links  42 ,  46  and cylinders  50 ,  54 , which are shown in the sectional views of  FIG. 10, 11 and 12 , left front link  42  has a top pivot  70  and bottom pivot  72 . Left rear link  46  has a top pivot  74  and a bottom pivot  76 . Left front cylinder  50  has an upper pivot connects at link bottom pivot  72  and a lower cylinder pivot  82 . Left rear cylinder  54  has an upper pivot  84  and a lower pivot  84 . The relative terms top, bottom, upper and lower refer to the orientation of the components when in the bunk bed position. 
         [0034]    Front link bottom pivot  72  is formed and arranged to slide in guide slot  28  thereby providing the range of motion needed to permit the bunk frame  30  to move vertically, while also remaining in a substantially horizontal orientation. Rear link bottom pivot  76  is mounted to tab  68  in a fixed location so as to permit link  46  to rotate about pivot  76  front link top pivot  70  and rear link top pivot  74  are mounted in fixed front and rear locations on upper bunk frame  30 . 
         [0035]    Left front cylinder  50  is mounted with front cylinder lower pivot  82  in a fixed location on plate  22  and front cylinder upper pivot connected at front link bottom pivot  72 . As pivot  72  slides in angled slot  28  pivot  84  causes compression of cylinder  50 , however as bunk frame  30  is moved first upwardly and frontwardly and then continuing upwardly and rearwardly, cylinder  50  extends to aid in raising frame  30  to the bunk bed position  56 . This movement works together with rear cylinder  54  and rear link  46  through mounting rear cylinder lower pivot  84  on tab  68  with rear cylinder upper pivot  84  mounted to the median portion of rear link  46 . These references refer to the sectional views and the opposite side will be a mirror image of that shown and described. 
         [0036]    As frame  30  is moved from the sofa position toward the mid position, left rear cylinder  54  compresses slightly, but as link  46  passes the axis of cylinder  54 , then cylinder  54  urges link  46  upward toward bunk bed position  56 . In bunk bed position  56  each of right and left front cylinders,  48 ,  50  and right and left rear cylinders,  52 ,  54  may be locked. At this time the ladder  58  and brace  60  are also locked at lock mechanisms  64 . The bed is converted to a sofa in substantially the reverse manner. 
         [0037]    The geometry of links right and left front links  40 ,  42 , right and left rear links  44 ,  46  and their respective front link top pivot  70  front link bottom pivot  72 , rear link top pivot  74 , rear link bottom pivot  76 , front cylinder upper pivot  80 , front cylinder lower pivot  82 , rear cylinder upper pivot  84  and rear cylinder lower pivot  86  is such that manual deployment may be accomplished as described, while alternative cylinders and other actuators and controls could be utilized for automatic deployment. 
         [0038]    The mattress  90  shown in  FIGS. 3, 11, 12 and 13  and the cushions shown in  FIGS. 12 and 13  can advantageously be arranged so that the mattress  90  remains in the same position, either under the frame  30  when in the sofa position or available for sleeping in the bunk bed position  56 . Seat cushion  92  may be thick enough to serve as a top mattress on the top bunk, or seat back cushion  94  could be formed in a foldable manner and unfolded from the sofa seat back configuration to a sleeping configuration. Cushion  92  could remain and be combined with cushion  94  for double the thickness. 
         [0039]    In the alternative embodiments shown in  FIGS. 15, 16, 17 and 18  sectional views at section A-A of  FIG. 1 , different configurations of tracks and links provide properties that may be tailored to specifically desired performance relative to the movement, compactness, strength and mechanical rigidity, noting sofa bed  10  right side frame  14  solid plates  22  guide slot  28  right front link  40  right rear link  44 , right front cylinders  48  and right rear cylinder,  54  generally formed and arranged as described above but with specific variations controlling the movement of the bunk bed assembly as it is raised and lowered. In  FIG. 15  and  FIG. 16  slot  28  has a lower straight portion, a forwardly curving intermediate portion and an upwardly curving upward portion.  FIG. 16  has increased size component sections and reinforcing members on plate  22 .  FIGS. 17 and 18  have some of the components removed for clarity, but show slot  28  in different configurations.  FIG. 17  shows slot  28  in a nearly vertical orientation, with a generally straight lower portion an intermediate curve and a generally straight upward portion. In  FIG. 18  slot  28  has a near vertical lower portion a forwardly curving intermediate portion and a straight upper portion.