Patent Publication Number: US-9414688-B2

Title: Convertible sofa-bed

Description:
This invention relates to convertible sofa-beds and in particular a convertible sofa-bed used in recreational vehicles and the like. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Convertible sofa-beds are highly desirable in applications where living space is limited, such as with recreational vehicles. Convertible sofa-beds typically include a base structure and a plurality of upholstered platform sections, which form the seat and backrest and can be manually shifted relative to the base frame between a sofa configuration and a bed configuration. Heretofore, pivots, hinges, linkages and tracks are used to convert the platform sections between the folded sofa and unfolded bed positions. 
     The convertible sofa-bed embodying this invention includes a base, a sliding and pivoting seat, a fold-out extension pivotally connected to the seat, and a fold-down seat back pivotally mounted to the base. The seat is pivotally connected to a pair of slides that ride on side rails mounted to the base, which allow the seat to manually shift between a horizontal seat position over the base and a horizontal bed position spaced from the base. The seat is also pivotally connected to the slide by a ball joint that allows the seat to pivot upward so that the extension can be unfolded from beneath the seat. The ball joint connection between the slides and seat frame prevents the seat from binding when shifted between the seat position and the bed position even if the seat is not perfectly square with respect to the side rails as it is manually lifted and moved. 
     The above described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may take form in various system and method components and arrangement of system and method components. The drawings are only for purposes of illustrating exemplary embodiments and are not to be construed as limiting the invention. The drawings illustrate the present invention, in which: 
         FIG. 1  is a perspective view of an exemplary embodiment of the convertible sofa-bed of this invention shown in the sofa orientation; 
         FIG. 2  is a perspective view of the convertible sofa-bed of  FIG. 1  shown in the bed orientation; 
         FIG. 3  is a top view of the convertible sofa-bed of  FIG. 1  with a portion of the cushions cut away to shown the internal frames; 
         FIG. 4  is a partial exploded view of the side rails and slides used in the convertible sofa-bed of  FIG. 1 ; 
         FIG. 5  is a perspective view of the slides used in the sofa-bed of  FIG. 1 ; 
         FIG. 6  is a top view with a portion cut away of the slide of  FIG. 5 ; 
         FIG. 7  is an end sectional view of the slide of  FIG. 5  taken along line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a partial end view of the rail and slide mechanism affixed to the seat frame as used in the convertible sofa-bed of  FIG. 1 ; 
         FIG. 9  is a top view with portions cutaway of the rail and slide mechanism affixed to the seat frame as used in the convertible sofa-bed of  FIG. 1 ; 
         FIG. 10  is a side view of the internal frames used in the convertible sofa-bed of  FIG. 1  shown in an intermediate orientation with the seat lifted; 
         FIG. 11  is a side view of the internal frames used in the convertible sofa-bed of  FIG. 1  shown in the bed orientation. 
         FIG. 12  is a top view of the internal frames used in the convertible sofa-bed of  FIG. 1  showing the seat frame square with the base frame; 
         FIG. 13  is a top view of the internal frames used in the convertible sofa-bed of  FIG. 1  showing the seat frame slightly misaligned with the base frame during conversion between the sofa and bed orientations; 
         FIG. 14  is another top view of the internal frames used in the convertible sofa-bed of  FIG. 1  showing the seat frame slightly misaligned with the base frame during conversion between the sofa and bed orientations; and 
         FIG. 15  is a top view of an alternative embodiment of the ball joint connection used with the slide and the seat frame. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical, structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the invention, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. 
     Referring now to the drawings,  FIGS. 1-6  illustrate an exemplary embodiment of the convertible sofa-bed of this invention, which is designated generally as reference numeral  100 . Convertible sofa-bed  100  can be manually moved between a sofa orientation ( FIG. 1 ) and a bed orientation ( FIG. 2 ). Sofa/bed  100  includes a base  110 , a sliding and pivoting seat  150  and a fold-out extension  160 , and a fold-down seat back  170 . Seat  150  is pivotally connected to a pair of slides  130  that ride on side rails  120  mounted to base  110  that allow the seat to be manually shifted between a horizontal seat position over the base ( FIG. 1 ) and a horizontal bed position spaced from the base ( FIG. 2 ). In addition, seat  150  is pivotally connected to slides  130  by a ball joint  140  that allows the seat to pivot upward so that extension  160  can be unfolded from beneath the seat. Extension  160  is pivotally connected to the seat to be manually pivoted between a storage position folded under the seat within the base  110  when the sofa-bed  100  is in the sofa orientation and a extended position unfolded from the seat ( FIG. 2 ) when the sofa-bed is in the bed orientation. Seat back  170  is connected to sofa base  110  for pivotal movement between a raised upright position ( FIG. 1 ) and lowered prone position ( FIG. 2 ). In the sofa orientation, seat  150 , extension  160  and back rest  170  are supported atop the base in a generally co-planar relation. In the sofa orientation, back rest  170  is pivoted upright, seat  150  is shifted rearward and bed extension  160  is disposed within sofa base  110  folded underneath the seat. 
     Sofa base  110 , seat  150 , extension  160  and back rest  170  each have an internal frame  112 ,  152 ,  162  and  172 , respectively. These internal frames are typically constructed from welded lengths of metal tubing and channel with various bracketed reinforcements. In other embodiments, the base frame may be constructed of wood or other suitable materials. Seat frame  52  and extension frame  162  each includes a pair of hinge brackets  154  and  164 . Extension frame  162  is pivotally connected to seat frame  152  by fasteners  156  that extend through aligned bores in hinge brackets  154  and  164 . Hinge bracket  164  also act as stop blocks, which hold extension frame  162  in longitudinal alignment with seat frame  152  when unfolded. Seat frame  152  includes a pair of slide brackets  148 . Seat back frame  122  is pivotally connected to a cross member  126  of base frame  112  by a pair of hinges  174 . Although hinges are shown in this embodiment, any method of pivotal connection can be incorporated. 
     Side rails  120  are mounted at opposite ends of base frame  112  by any suitable means, such as screws or welds. Side rails  120  are typically lengths of square metal tubing or C-channel cut or bent to have inward facing longitudinal slots  121 . Rails  120  act as tracks for slides  130 . A slide  130  is carried within each side rail  120  for traverse movement along the length of the rails. Slides  130  are typically fashioned or formed from a block of low friction material, such as Teflon and configured to conform to geometric configuration of side rails  120 . Each slide  130  also has a counter sunk through bore  131 . Seat frame  152  is pivotally connected to each slide  130  by a bolt  140  extending through counter suck bore  131 . Bolt  140  includes a bolt head  142  and an elongated threaded shaft  144 . As shown in  FIGS. 8 and 9 , bolt head  142  is disposed within counter sunk bore  131  and thread shaft  144  extends through a bore in slide bracket  148  and is secured by a lock nut  146 . Bolt  140  allows seat  130  to be manually raised and lowered relative to the sofa base  110 . In addition, counter sunk bore  131  and bolt  140  act as a ball joint and each are dimensioned to provide a measure or angular play so that seat  150  does not bind when moving between the seat position and the bed position ( FIGS. 12-14 ). As shown, bolt head  142  seats against a shoulder  137  formed in counter sunk bore  131 . The diameter of the bore walls and the shaft are dimensions to provide sufficient play and movement so that slides  130  will travel smoothly along side rails  120  even if seat frame  152  is not perfectly square with respect to the side rails as it is manually lifted and moved. 
       FIG. 15  shows an alternative embodiment of the ball joint provided by a slide  230  and a specialized connector  240 . Slide  230  again has a threaded countersunk bore  231 . Connector  240  has a round head  292  and threaded shaft  244 . Head  292  is seated within the counter sunk bore  231  of slide  230 . Bore  231  has concave inner shoulders  237 , which form a joint socket or seat to accommodate head  192 . Bore  231  is enclosed by a thread plug  248 , which seats against head  242  and prevents lateral movement of connector  240  within bore  231 . 
     Extension  140  also includes a pair of folding legs  144 . Folding legs  144  support extension  140  when sofa/bed  100  is in its horizontal bed position ( FIG. 2 ) and fold flat against extension frame  142  when the sofa/bed  100  is in its sofa position ( FIG. 1 ). Folding legs  148  are pivotally mounted to bed extension frame  152  by hinges (not shown). In the sofa orientation, the legs  148  are folded beneath the extension frame  142 . In the bed orientation, the legs  148  are extended as shown to support extension  140  which extends from seat  130 . Legs  148  are preferably formed of metal, in a tubular form, or any other material sufficient to support weight borne by the convertible sofa-bed  100  when in the bed orientation. Legs  148  are locked into their deployed position by any suitable mechanism, such as a snap key or other mechanical lock (not shown). 
     As best shown in  FIG. 3 , sofa-bed  100  also includes lock mechanism  180  mounted to extension frame  162 , which holds and locks seat  150  and extension  160  in the bed orientation. Lock mechanism  180  may be of any conventional design and function. As shown, lock mechanism  180  includes a locking part  182  mounted to the bottom of seat frame  152  that restrictively engages both the seat frame  152  and the extension frame  162 . Locking part  182  is operatively connected to a pull knob  186  by a cable  184 . Mannually pulling knob  186  deactivates locking part  182  and allows seat  150  and extension  160  to be manually moved from the bed orientation to the sofa orientation. 
     As shown, base frame  112  is covered with a padded upholstery of cloth, leather or vinyl. Seat, extension and beck bask frames  152 ,  162  and  172  supports removable cushions  131 ,  141  and  151 . Seat, extension and seat back frames  152 ,  162 ,  172  includes a plurality of suspension bands that form a platform on which cushions or padded upholstery are supported. While the spaced bands are illustrated in the drawings, other embodiments of the internal frame may includes a solid surface platform, wire supports, springs and any other means of supporting the cushions and padded upholstery. Cushions  151 ,  161  and  171  are of conventional construction and typically fashioned of a medium or high density foam body covered in cloth, vinyl or leather with a zipper or other suitable closure to allow replacement of the foam body. Removable cushions may be secured to their respective frames using hook and loop fasteners, snaps, or any other suitable method, which prevents the cushions from shifting atop the cushion frame as the sofa/bed is moved between the sofa and bed positions. Otherwise, the cushions may simply be placed atop the frames. While cushions  151 ,  161  and  171  are illustrated as removable cushions supported by atop or against frames  152 ,  162  and  172 , in alternative embodiments, one or more of the cushions may be affixed directly to the frames or the internal frames simply covered with an padded upholstery, as desired. 
     To move sofa-bed  100  from the sofa orientation ( FIG. 1 ) to the bed orientation ( FIG. 2 ), seat  150  is lifted upward and slid forward. With seat  150  lifted and slid forward, extension  160  can be pivoted outward and legs  166  unfolded. Typically, locking part  182  activates once extension  160  is fully unfolded. Once legs  166  are unfolded, seat  150  and extension  160  can be lowered and seat back  170  pivoted downward into its lowered position. To return sofa/bed  100  from the bed orientation ( FIG. 2 ) to the sofa orientation ( FIG. 1 ), seat back  120  is first manually raised to its upright position. Next, lock mechanism  180  is deactivated to allow extension  160  to be stowed under seat  150 . Seat  150  is manually raised pivoting upward away form sofa base  110 . Extension legs  166  are folded under extension frame  162  and extension  160  is pivoted back under seat  150 . Once extension  160  is stowed, seat  150  is lowered and slid back over sofa base  110  to its sofa position. 
     One skilled in the art will note several advantages of the convertible sofa-bed embodying this invention over conventional convertible sofa-beds. The use of rail mounted slides allows the seat to glide smoothly between the sofa and bed positions with little manual force. In addition, the use of ball joint connection between the slides and seat frame not only allows the seat to pivot upward to give access to the extension but reduces any binding when the seat is moved between the sofa and bed position. Reducing the binding that occurs when the seat is not perfectly square to the rails further improves the ease of operation. 
     It should be apparent from the foregoing that an invention having significant advantages has been provided. While the invention is shown in only a few of its forms, it is not just limited but is susceptible to various changes and modifications without departing from the spirit thereof. The embodiment of the present invention herein described and illustrated is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is presented to explain the invention so that others skilled in the art might utilize its teachings. The embodiment of the present invention may be modified within the scope of the following claims.