Patent Publication Number: US-10327560-B2

Title: Convertible sofa with articulated arm rests

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims benefit of U.S. Provisional Patent Application Nos. 62/108,729, filed on Jan. 28, 2015, and 62/153,786, filed on Apr. 28, 2015, and incorporates herein by reference the disclosures thereof in their entireties. 
    
    
     BACKGROUND AND SUMMARY OF THE DISCLOSURE 
     The disclosure is directed to a convertible sofa that can be selectively configured as a sofa and as a bed. More particularly, the disclosure is directed to a convertible sofa having articulated arm rests that are configured as armrests when the convertible sofa is in a sofa configuration and that fold to a generally or relatively flat configuration when the convertible sofa is in a bed configuration. 
     Convertible sofas having arm rests are known in the art. Such convertible sofas typically have either a pull-out conversion mechanism or a jackknife conversion mechanism. In either case, the armrests typically are fixed. That is, they assume a single configuration regardless of whether the convertible sofa is in a sofa configuration or a bed configuration. 
     When a typical pull-out convertible sofa is placed in the bed configuration, the resulting sleeping surface is oriented such that the arm rests flank the upper body of a user lying on the sleeping surface. As such, the arm rests may serve as side bolsters when the sofa is in a bed configuration. This may inhibit persons from entering and exiting the bed. 
     When a typical jackknife convertible sofa is placed in the bed configuration, the resulting sleeping surface is oriented such that the head and feet of a user lying on the sleeping surface are adjacent respective ones of the arm rests. As such, the arm rests may serve as head and foot boards. This may present a problem for taller users whose height exceeds the distance between the arm rests. 
     Also known are jackknife convertible sofas lacking integral arm rests. Such jackknife convertible sofas may be provided with removable, auxiliary arm rests. Such arm rests typically are made of an upholstered foam material. They can be attached to the convertible sofa when the convertible sofa is in a sofa configuration, and removed from the convertible sofa when it is to be placed in a bed configuration. This may present a problem in that the removable arm rests may clutter the space about the convertible sofa when removed there from. Also, the attachment of the arm rests to the convertible sofa may be complicated and/or unsecure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of an illustrative convertible sofa frame in a sofa configuration; 
         FIG. 1B  is a side view of an illustrative convertible sofa frame in a sofa configuration; 
         FIG. 2A  is a perspective view of an illustrative convertible sofa frame in a first configuration intermediate a sofa configuration and a bed configuration; 
         FIG. 2B  is a side view of an illustrative convertible sofa frame in a first configuration intermediate a sofa configuration and a bed configuration; 
         FIG. 3A  is a perspective view of an illustrative convertible sofa frame in a second configuration intermediate a sofa configuration and a bed configuration; 
         FIG. 3B  is a side view of an illustrative convertible sofa frame in a second configuration intermediate a sofa configuration and a bed configuration; 
         FIG. 4A  is a perspective view of an illustrative convertible sofa frame in a third configuration intermediate a sofa configuration and a bed configuration; 
         FIG. 4B  is a side view of an illustrative convertible sofa frame in a third configuration intermediate a sofa configuration and a bed configuration; 
         FIG. 5A  is a perspective view of an illustrative convertible sofa frame in a bed configuration; 
         FIG. 5B  is a side view of an illustrative convertible sofa frame in a bed configuration; 
         FIG. 6A  is a top plan view of another illustrative convertible sofa frame in a sofa configuration; 
         FIG. 6B  is a front elevation view of another illustrative convertible sofa frame in a sofa configuration; 
         FIG. 6C  is a perspective view of another illustrative convertible sofa frame in a sofa configuration; 
         FIG. 6D  is an end elevation view of another illustrative convertible sofa frame in a sofa configuration; 
         FIG. 7A  is a top plan view of another illustrative convertible sofa frame in a bed configuration; 
         FIG. 7B  is a front elevation view of another illustrative convertible sofa frame in a bed configuration; 
         FIG. 7C  is a perspective view of another illustrative convertible sofa frame in a bed configuration; 
         FIG. 7D  is an end elevation view of another illustrative convertible sofa frame in a bed configuration; 
         FIGS. 8A-8E , respectively are perspective views of another illustrative convertible sofa frame in a sofa configuration, a first configuration intermediate a sofa configuration and a bed configuration, a second configuration intermediate a sofa configuration and a bed configuration, a third configuration intermediate a sofa configuration and a bed configuration, and a bed configuration; 
         FIGS. 9A-9E , respectively are end elevation views of another illustrative convertible sofa frame in a sofa configuration, a first configuration intermediate a sofa configuration and a bed configuration, a second configuration intermediate a sofa configuration and a bed configuration, a third configuration intermediate a sofa configuration and a bed configuration, and a bed configuration; 
         FIG. 10  is an end elevation view of a seat frame bracket of an illustrative convertible sofa frame; 
         FIG. 11  is an end elevation view of a back frame bracket of an illustrative convertible sofa frame; 
         FIG. 12  is a view of an illustrative convertible sofa frame in a sofa configuration and with cushions attached thereto; 
         FIG. 13  is a view of an illustrative convertible sofa frame in a bed configuration and with cushions attached thereto; and 
         FIG. 14  is a side elevation view of a cushion for an illustrative convertible sofa frame. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Terms of orientation, for example, front, rear, upper, lower, side, inner, outer, and the like, may be used herein to describe relative orientation of components. Such terms are to be construed in a relative sense, rather than an absolute sense, unless context clearly dictates otherwise. 
       FIGS. 1A-5B and 10-11  show an illustrative embodiment of a convertible sofa frame  10  that can be configured in a sofa configuration (see  FIGS. 1A and 1B ) or a bed configuration (see  FIGS. 5A and 5B ). The frame  10  includes articulated arm rests  12  that unfold from an armrest configuration (see  FIGS. 1A and 1B ) when the frame is in a sofa configuration to a generally flat configuration (see  FIGS. 5A and 5B ) when the frame is in a bed configuration. The frame  10  also includes a seat frame  14  and a back frame  16 . 
     The seat frame  14  includes a central portion having a front rail  14 F, a rear rail  14 R, and left and right side rails  14 S connecting the front rail  14 F to the rear rail  14 R at or near ends thereof. One or more seat springs  18  are connected to and span the space between the front rail  14 F and rear rail  14 R of the seat frame  14 . The seat springs  18  may form a base for a seat cushion (not shown) that may be disposed thereon. In other embodiments, the seat springs  18  may be connected to and span the space between opposing side rails  14 S of the seat frame  14 . In either embodiment, the seat springs could be attached to the rails  14 F,  14 R,  14 S in any suitable manner. One(s) of the seat springs  18  could, but need not, be interconnected with another (others) of the seat springs  18 . 
     The seat springs  18  are shown as conventional S-shaped seat springs. In other embodiments, the seat springs  18  could take other forms. Alternatively, the seat springs  18  could be omitted. In embodiments not including seat springs  18 , one or more generally rigid cross members (not shown) could span the space between front rail  14 F and rear rail  14 R or between opposing side rails  14 S. Such cross members could be attached to the rails  14 F,  14 R,  14 S in any suitable manner. 
     In the illustrated embodiment, a crosstie  20  is attached to and extends between the front rail  14 F and the rear rail  14 R to mitigate or preclude flexing or bowing of the front rail  14 F toward the rear rail  14 R, for example, in response to a load placed upon the seat springs  18 . The crosstie  20  may be generally rigid or incompressible in an axial direction and generally flexible or generally rigid in a transverse direction. In the illustrated embodiment, the crosstie  20  is located midway or about midway between the opposing side rails  14 S. In other embodiments, the crosstie  20  could be located nearer one or the other of the side rails  14 S. In further embodiments, plural crossties  20  could traverse the space between the front and rear rails  14 F,  14 R, at any suitable or desired location with respect thereto. First and second longitudinal tie rods  22  similar to the crosstie  20  are attached to and extends between the left and right side rails  14 S. In the illustrated embodiment, the first longitudinal tie rod  22  is located near the rear rail  14 R, and the second longitudinal tie rod  22  is located near the front rail  14 F. In other embodiments, the longitudinal tie rods  22  could be located elsewhere. Other embodiments could include more or fewer longitudinal tie rods  22  located where desired. In an embodiment, any or all of the crossties  20  and longitudinal tie rods  22  could be omitted. 
     A seat frame extension  24  extends laterally outwardly from each side of the central portion of the seat frame  14 . The seat frame extensions  24  may be formed contiguously with one or both of the front and side rails  14 F,  14 S, or they may formed separately and attached to the central portion of the seat frame  14 . The seat frame extensions  24  are shown as generally rectangular, having a front rail  24 F, a rear rail  24 R and an outboard side rail  24 S, and having a rounded outboard front corner where the side rail  24 S joins the front rail  24 F. In other embodiments, the seat frame extensions  24  could have other shapes. Each seat frame extension  24  is shown as having a crosstie rod  26  attached to and extending between the front rail  24 F and the rear rail  24 R, proximate the side rail  24 S. Each seat frame extension  24  also is shown as including first and second longitudinal tie rods  28  extending from the side rail  24 S of the seat frame extension  24  to the corresponding side rail  14 S of the central portion of the seat frame  14 . The first longitudinal tie rod  28  is near the rear rail  24 R and the second longitudinal tie rod  28  is near the front rail  24 F. In other embodiments, the seat frame extensions  24  could include more or fewer (or no) cross ties  26  and/or longitudinal tie rods  28 . Where included, cross ties  26  and/or longitudinal tie rods  28  could be located where desired. 
     A seat frame bracket  30  is attached to each side rail  14 S of the central portion of the seat frame  14 . The seat frame bracket  30  is shown as a generally diamond-shaped plate which, as best shown in  FIG. 10 , includes an upper web  30 U offset in a laterally outward direction from a lower web  30 L by an intermediate web  301 . A lower edge of the seat frame bracket  30  runs generally parallel to the axial dimension of the side rail  14 S. A flange  30 F may extend from the foregoing edge of the seat frame bracket  30  so that the flange and adjoining portion of the lower web  30 L of the seat frame bracket “cradle” a corresponding portion of the side rail  14 S. In other embodiments, the seat frame bracket  30  could have other configurations. 
     The back frame  16  includes a central portion including an upper rail  16 U, a lower rail  16 L, and a pair of opposing left and right side rails  16 S. A plurality of stringers  34  extend between the upper rail  16 U and lower rail  16 L. The stringers  34  are shown as strips, ones of which extend between the upper rail  16 U and lower rail  16 L along a front side thereof and others of which extend between the upper rail  16 U and lower rail  16 L along a rear side thereof. In the illustrated embodiment, the stringers  34  are strips of cloth or other fabric wrapped around the upper and lower rails  16 U,  16 L and spanning the front and rear sides of the back frame  16 . The ends of each such piece of cloth or other fabric may be glued or sewn or heat staked together to form a continuous loop of material. Alternatively, each stringer  34  may be a distinct element made of, for example, a cloth, metal, plastic, or other material attached to the upper and lower rails  16 U,  16 L. In an embodiment, stringers  34  could span only the front or rear side of the back frame  16 . In another embodiment, the stringers  34  could be omitted and replaced with panels (not shown) covering substantially larger areas of the front and/or rear sides of the back frame  16 . 
     In the illustrated embodiment, first and second longitudinal tie rods  36  are attached to and extend between the left and right side rails  16 S. The first longitudinal tie rod  36  is near the upper rail  16 U, and the second longitudinal tie rod  36  is near the lower rail  16 L. A crosstie  35  similar to crosstie  20  extends between the upper and lower rails  16 U,  16 L. Other embodiments could include additional tie rods extending between the side rails  16 S or between the upper and lower rails  16 U,  16 L. Further embodiments could include fewer or no tie rods or crossties in the back frame  16 . The back frame crossties and tie rods could be located where desired. 
     A back frame extension  40  extends laterally outwardly from each side of the central portion of the back rest frame  16 . The back frame extensions  40  as shown are identical to the seat frame extensions  24 . In other embodiments, the back frame extensions  40  could be configured in other ways. 
     In an embodiment, the seat frame extensions  24  and/or back frame extensions  40  may be integral with the seat frame  14  and/or the back frame  16 , respectively, rather than discrete elements. 
     A back frame bracket  32  is attached to each side rail  16 S of the central portion of the back frame  16 . Each back frame bracket  32 , as shown, may include a forward web  32 F, a rearward web  32 R, and an intermediate web  32 I. As illustrated, the back frame bracket  32  is the inverted mirror image of the seat frame bracket  30 . In other embodiments, the back frame bracket  32  could have other configurations. A rear edge of the back frame bracket  32  runs generally parallel to the axial dimension of the side rail  16 S. A flange  32 FL may extend from the foregoing edge of the back frame bracket  32  so that the flange and adjoining portion of the back frame bracket “cradle” a corresponding portion of the side rail  16 S. 
     Each arm rest  12  includes a forward portion  42  and a rearward portion  44 . The forward portion  42  includes a lower rail  42 L, an upper rail  42 U and a pair of opposing left and right side rails  42 S. The rearward portion  44  similarly includes a front rail  44 F, a rear rail  44 R and a pair of opposing left and right side rails  44 S. 
     The rear rail  24 R of each seat frame extension  24  is connected to the lower rail  42 U of the forward portion  42  of the corresponding arm rest  12  by a first hinge  46 . The first hinge  46  is configured so that a forward-facing side or surface of the forward portion  42  of the arm rest  12  may fold toward an upward-facing side or surface of the seat frame extension  24 . The upper rail  42 U of the forward portion  42  of the arm rest  12  is connected to the front rail  44 F of the rearward portion  44  of the arm rest by a second hinge  48 . The second hinge  48  is configured so that a rearward-facing side or surface of the forward portion  42  of the arm rest  12  may fold toward a downward-facing side or surface of the rearward portion  44  of the arm rest  12 . The rear rail  44 R of the rearward portion  44  of the arm rest  12  is connected to the lower rail  36 L of the back frame extension  36  by a third hinge  50 . The third hinge  50  is configured so that an upward-facing side or surface of the rearward portion  44  of the arm rest  12  may fold toward a forward-facing side or surface of the back frame extension  36 . 
     Each of the hinges  46 ,  48 ,  50  is shown as a conventional hinge having first and second leaves joined in pivotal relationship by a hinge pin. In other embodiments, any suitable form of hinge could be used. 
     As best shown in  FIGS. 4B and 5B , each seat frame bracket  30  is pivotally connected to a corresponding back frame bracket  32  via a first pivot pin PP 1  at first pivot point P 1 . Each of the seat frame bracket  30  and back frame bracket  32  define a corresponding aperture for receiving the first pivot pin PP 1 . The first pivot point P 1  is selected so that the seat frame  14  and the back frame  16  may lie generally (though not necessarily absolutely) flat or horizontal when the convertible sofa frame  10  is in the bed configuration. See  FIGS. 5A and 5B . The first pivot point P 1  also is selected so that the seat frame  14  and back frame  16  may be disposed generally (though not necessarily absolutely) perpendicular to each other when the convertible sofa frame  10  is in a sofa configuration to allow for a comfortable seating position. See  FIGS. 1A and 1B  (wherein the angle between the upward-facing side or surface of the seat frame  14  and the forward-facing side or surface of the back frame  16  is slightly greater than 90°). 
     Each seat frame bracket  30  and back frame bracket  32  is pivotally connected to a corresponding mounting bracket  52  through a corresponding linkage, as will be discussed further below. The mounting bracket  52  is shown as a structural angle having an elongated side flange  52 S and an elongated base flange  52 B generally perpendicular to the side flange. The side flange  52 S defines a plurality of apertures for receiving pivot pins, as will be discussed further below. The base flange  52 B defines a plurality of apertures for receiving fasteners (not shown) that may be used, for example, to secure the mounting bracket  52  to a structure, for example, the floor of a recreational vehicle. Frame supports  62  extend inwardly from the side flange  52 S and/or base flange  52 B of the mounting bracket  52 . The frame supports  62  provide support for the seat frame  14  and back frame  16  when the seat frame  14  and/or back frame  16  are in a generally horizontal or flat orientation. For example, the seat frame  14  may rest upon the forward pair of frame supports  62  when the convertible sofa is in the sofa configuration or the bed configuration (but typically not when the convertible sofa is being reconfigured between these two configurations), and the back frame  16  may rest upon the frame supports  62  when the convertible sofa is in the bed configuration. The frame supports are shown is U-shaped channels but could be embodied in various other ways, for example, as bars or pins. 
     Each seat frame bracket  30  is pivotally connected by a second pivot pin PP 2  at a second pivot point P 2  to a first end of a corresponding first link  54 . Each first link  54  is shown as dogleg-shaped (shaped like a splayed letter “V”), but it could have other shapes allowing for the placement of three apertures therein in a non-linear arrangement. The second end of each first link  54  is pivotally connected by a third pivot pin PP 3  at a third pivot point P 3  to the side flange  52 S of the corresponding mounting bracket  52 . 
     Each back frame bracket  32  is pivotally connected by a fourth pivot pin PP 4  at a fourth pivot point P 4  to a first end of a corresponding second link  56 . Each second link  56  is shown as dogleg-shaped, but it could have other shapes allowing for the placement of three apertures therein in a non-linear arrangement. The second end of each second link  56  is pivotally connected by a fifth pivot pin PP 5  at a fifth pivot point P 5  to the side flange  52 S of the corresponding mounting bracket  52 . 
     Each first link  54  is pivotally connected to the corresponding second link via a corresponding third link  58 . More specifically, a first end of each third link  58  is pivotally connected by a sixth pivot pin PP 6  at a sixth pivot point P 6  to the first link  54 . As illustrated, the sixth pivot point P 6  is located at or about the crux  54 C of the dogleg of the first link  54 . In other embodiments, the sixth pivot point P 6  could be located at a suitable location not collinear with the second and third pivot points P 2  and P 3 . The second end of each third link  58  is pivotally connected by a seventh pivot pin PP 7  at a seventh pivot point P 7  to the corresponding second link  56 . As illustrated, the seventh pivot point P 7  is located about midway between the fourth pivot point P 4  and the crux  56 C of the dogleg of the second link  56 . In other embodiments, the seventh pivot point P 7  could be located at another suitable location not collinear with the fourth and fifth pivot points P 4  and P 5 . 
     In operation, the sofa frame  10  may be placed in a sofa configuration wherein the seat frame  12  and rearward portion  38  of the arm rest  12  are generally (though not necessarily absolutely) horizontal, and the back frame  16  and forward portion  36  of the arm rest  12  are generally (though not necessarily absolutely) vertical. See  FIGS. 1A and 1B . 
     The sofa frame  10  may be converted to a bed configuration by lifting, pulling forward, and lowering the front end of the seat frame  12  through a sequence as shown, for example, in  FIGS. 2A and 2B  through  FIGS. 5A and 5B , as discussed further below. 
     In  FIGS. 2A and 2B  the forward portion of the seat frame  14  has been pulled forward and raised through an initial distance and arc compared to the configuration shown in  FIGS. 1A and 1B . Consequently, (1) the upward facing side or surface of the seat frame  14  has been folded toward the forward-facing side or surface of the back frame  16 , (2) the forward-facing side or surface of the forward portion of the arm rest  12  has been folded toward the upward-facing side or surface of the seat frame extension, (3) the rearward facing side or surface of the forward portion of the arm rest  12  has been folded toward the downward-facing side or surface of the rearward portion of the arm rest  12 , (4) the upward-facing side or surface of the rearward portion of the arm rest  12  has been folded toward the forward-facing side or surface of the back frame extension, (5) and the first ends of the first and second links  54  and  56  have pivoted toward the front of the mounting bracket  52 . 
     In  FIGS. 3A and 3B , the forward portion of the seat frame  14  has been pulled forward and raised through an additional distance and arc compared to the configuration shown in  FIGS. 2A and 2B . Consequently, (1) the upward facing side or surface of the seat frame  14  has been folded further toward the forward-facing side or surface of the back frame  16 , (2) the forward-facing side or surface of the forward portion of the arm rest  12  has been folded further toward the upward-facing side or surface of the seat frame extension, (3) the rearward facing side or surface of the forward portion of the arm rest  12  has been folded further toward the downward-facing side or surface of the rearward portion of the arm rest  12 , (4) the upward-facing side or surface of the rearward portion of the arm rest  12  has been folded further toward the forward-facing side or surface of the back frame extension, (5) and the first ends of the first and second links  54  and  56  have pivoted further toward the front of the mounting bracket  52 . 
     In  FIGS. 4A and 4B , the forward portion of the seat frame  14  has been pulled further forward and lowered compared to the configuration shown in  FIGS. 3A and 3B . Consequently, (1) the upward facing side or surface of the seat frame  14  has been unfolded away from the forward-facing side or surface of the back frame  16 , (2) the forward-facing side or surface of the forward portion of the arm rest  12  has been unfolded away from the upward-facing side or surface of the seat frame extension, (3) the rearward facing side or surface of the forward portion of the arm rest  12  has been unfolded away from the downward-facing side or surface of the rearward portion of the arm rest  12 , (4) the upward-facing side or surface of the rearward portion of the arm rest  12  has been unfolded away from the forward-facing side or surface of the back frame extension, (5) and the first ends of the first and second links  54  and  56  have pivoted further toward the front of the mounting bracket  52 . 
     In  FIGS. 5A and 5B , the forward portion of the seat frame  14  has been pulled further forward and further lowered compared to the configuration shown in  FIGS. 4A and 4B . Consequently, (1) the upward facing side or surface of the seat frame  14  has been unfolded further away from the forward-facing side or surface of the back frame  16 , (2) the forward-facing side or surface of the forward portion of the arm rest  12  has been unfolded further away from the upward-facing side or surface of the seat frame extension, (3) the rearward facing side or surface of the forward portion of the arm rest  12  has been unfolded further away from the downward-facing side or surface of the rearward portion of the arm rest  12 , (4) the upward-facing side or surface of the rearward portion of the arm rest  12  has been unfolded further away from the forward-facing side or surface of the back frame extension, (5) and the first ends of the first and second links  54  and  56  have pivoted further toward the front of the mounting bracket  52 . In the  FIGS. 5A and 5B  configuration, all of the seat frame  14 , the back frame  16 , the forward portion of the arm rest  12 , and the rearward portion of the arm rest  12  are in a generally (though not necessarily absolutely) flat or horizontal configuration. In an embodiment, at least the seat frame  14  and the back frame  16  may be in an absolutely flat or horizontal configuration when the convertible sofa frame  10  is in the bed configuration. 
     The convertible sofa frame  10  can be converted from the bed configuration of  FIGS. 5A and 5B  to the sofa configuration of  FIGS. 1A and 1B  through a reverse procedure. 
     A bumper  60  may be provided at the rear of the forward portion  42  of the arm rest  12  or the front of the rearward portion  44  of the arm rest. The bumper  60  may be configured to bias apart the forward and rearward portions  42 ,  44  of the arm rest  12  when the convertible sofa frame is in the bed configuration to preclude “locking” of the forward and rearward portions of the arm rest. As such, the bumper  60  may aid in transitioning the forward and rearward portions  42 ,  44  of the arm rest  12  from the “flat” configuration to the “arm rest” configuration when the convertible sofa  10  is transitioned from the bed configuration to the sofa configuration. Bumper  60  may be a resilient structure, for example, a resilient rubber structure or a spring. In other embodiments, the bumper  60  may be omitted. In further embodiments, another form of biasing mechanism may be provided in place of or in addition to the bumper  60 . For example, a torsion spring (not shown) may be provided in connection with the pivotal connection between the front portion of the arm rest and the rear portion of the armrest and configured to bias the front portion of the arm rest and the rear portion of the armrest away from their configuration when the convertible sofa frame is in the bed configuration. 
     As shown in  FIG. 12 , a biasing mechanism, for example, a spring  60  connected between the mounting bracket  52  and the first link  54 , may be provided to assist a user in pulling the seat frame  14  forward with respect to the mounting bracket  52 , for example, when reconfiguring the convertible sofa frame  10  from the sofa configuration to the bed configuration, as described above. A similar biasing mechanism may be provided in connection with the convertible sofa frame  10 . 
     As shown in  FIGS. 12 and 13 , cushions  62 ,  64 ,  66  may be provided atop the seat frame  14  (and extensions  24  thereof), the back frame  16  (and extensions  40  thereof), and the arm rests  12  of the convertible sofa frame  10 . Any or all of cushions could be made of ticking or a resilient foam material. 
     As shown in  FIG. 14 , the underside of the cushions  66  atop the arm rests  12  (that is, the side of the cushions  66  abutting or adjacent to the arm rests) may be formed to accommodate portions of the arm rests that may extend above the plane of the upper surface of the seat frame  14  and the forward surface of the back frame  16  when the convertible sofa frame  10  is in the bed configuration, as suggested in  FIG. 5B  (and in  FIG. 7D , discussed below). For example, the underside of the cushions  66  could be partially hollowed out or formed to define a cavity  68  receiving such portions of the arm rests  12 . 
     The cushions  62 ,  64  could be formed to define one or more cavities similar to the cavity  68  of the cushion  66  as might be necessary or desired to accommodate any portion of the seat frame  14  and/or back frame  16  that might extend above the plane of the upper surface of the seat frame  14  and the forward surface of the back frame  16  when the convertible sofa frame  10  is in the bed configuration. 
     Also, the cushions  62 ,  66  could be tapered from front-to-back (that is, in a direction from the front of the convertible sofa frame toward the rear of the convertible sofa frame) to counter a less-than-horizontal orientation of the seat frame  14  and/or back frame  16  when the convertible sofa frame  10  is in the bed configuration. 
     In an embodiment, two or more of the cushions  62 ,  64 ,  66  could be embodied as a single cushion covering two or more of the seat frame  14 , the back frame  16 , and the arm rests  12 . Also, any or all of the cushions  62 ,  64 ,  66  could be embodied as a plurality of cushions. 
       FIGS. 6A-9E  show another illustrative convertible sofa frame  10 ′. The convertible sofa frame  10 ′ is similar in structure and operation to the convertible sofa frame  10 . Features of the convertible sofa frame  10 ′ having analogous counterparts in the convertible sofa frame  10  may be identified in the drawings by similar, primed reference characters. For example, the convertible sofa frame  10 ′ includes a seat frame  12 ′ analogous to the seat frame  10  of the convertible sofa frame  10 . Although the convertible sofa frame  10 ′ is similar in structure and operation to the convertible sofa frame  10  in many regards, the two differ as follows. 
     The seat frame extensions  24 ′ of the convertible sofa frame  10 ′ are shown as extending from the front rail  14 F′ to the rear rail  14 R′ of the seat frame  14 ′ thereof, whereas the seat frame extensions  24  of the convertible sofa frame  10  are shown as extending from the front rail  14 F of the seat frame  14  to a point forward of the forward portion  36  of the corresponding arm rest  12 . Similarly, the back frame extensions  40 ′ of the convertible sofa frame  10 ′ extend from the upper rail  16 U′ to the lower rail  16 L′ thereof, whereas the back frame extensions  40  of the convertible sofa frame  10  are shown as extending from the upper rail  16 U of the back frame  16 ′ to a point upward of the rearward portion  38  of the corresponding arm rest  12 . The seat frame extensions  24 ′ and back frame extensions  40 ′ of the convertible sofa frame  10 ′ may be integral with the seat frame  14 ′ and back frame  16 ′ thereof, rather than discrete elements. 
     Consequently, the pivot mechanisms or linkages (including the first link  54 ′, the second link  56 ′, and the third link  58 ′) connecting the seat frame  14 ′ to the back frame  16 ′ of the convertible sofa frame  10 ′ are outboard of the respective arm rests  12 ′, whereas the corresponding pivot mechanisms or linkages (including the first link  54 , the second link  56 , and the third link  58 ) of the convertible sofa frame  10  are inboard of the respective arm rests  12 . 
     Also, the forward portions  36 ′ of the arm rests  12 ′ of the convertible sofa frame  10 ′ are embodied as structural channels, each having a web  36 W and opposing parallel flanges  36 F extending in the same direction from opposite sides of the web, whereas the forward portions  36  of the arm rests  12  of the convertible sofa frame  10  are embodied as space frames made of tubular structures. The rearward portions  38 ′ of the arm rests  12 ′ of the convertible sofa frame  10 ′ are similarly embodied as structural channels, each having a web  38 W and opposing parallel flanges  38 F extending in the same direction from opposite sides of the web. 
     Further, the forward portions  36 ′ of the arm rests  12 ′ and the rearward portions  38 ′ of the arm rests of the convertible sofa frame  10 ′ are interconnected by pivot pins  56 PP extending through apertures (not shown) defined by the corresponding flanges  36 W,  38 W thereof near the adjoining ends thereof, whereas the corresponding portions of the convertible sofa frame  10  are connected by leaf-type hinges. As shown, the flanges of the forward end of the rearward portion  38 ′ of the arm rest  12 ′ overlap the flanges of the rearward end of the forward portion  36 ′ of the arm rest  12 ′. In another embodiment, the flanges of the rearward end of the forward portion  36 ′ of the arm rest  12 ′ could overlap the flanges of the forward end of the rearward portion  38 ′ of the arm rest  12 ′. 
     Moreover, the rearward portions  38 ′ of the arm rests  12 ′ of the convertible sofa frame  10 ′ are connected to the back frame  16 ′ thereof by pivot pins extending through the flanges of the rearward portions of the arm rests and corresponding brackets mounted to the back frame, whereas the rearward portions of the arm rests of the convertible sofa frame  10  are connected to the back frame extensions  40  thereof by leaf-type hinges. The forward portions  36 ′ of the arm rests  12 ′ are pivotally connected to the seat frame  14 ′ of the convertible sofa frame  10 ′ in a similar manner. 
     The convertible sofa frame  10 ′ is operable in the same manner as the convertible sofa frame  10 . 
     The convertible sofa frame  10 ′ may be provided with cushions similar to the cushions  62 ,  62 ,  66  described above in connection with the convertible sofa frame  10 . 
     The embodiments shown and described herein are illustrative and are not to be construed to limit the scope of the appended claims. Features shown a given embodiment may be included in another embodiment to the extent possible.