Folding futon support

A convertible sofabed particularly designed for use with a futon-type mattress. The sofabed includes a back frame and seat frame elements pivotally connected together and pivotally mounted on a pair of rigid end frame members to facilitate shifting the back frame and the seat frame units from sitting to sleeping position.

BACKGROUND OF THE INVENTION 
A number of different folding or convertible sofabeds have been designed in 
the past. These are exemplified in the following U.S. Pat. No. 3,905,053, 
issued Sep. 16, 1975 to VUCHELICH; U.S. Pat. No. 4,642,823, issued Feb. 
17, 1987 to WIGGINS; U.S. Pat. No. 4,829,611, issued May 16, 1989 to 
FIREMAN; U.S. Pat. No. 4,996,730, issued Mar. 5, 1991 to FIREMAN. All of 
these prior art references show convertible sofabed constructions. However 
none shows a convertible sofabed embodying this invention. 
SUMMARY OF THE INVENTION 
This invention is particularly adapted to provide an extremely durable 
structurally sound easily convertible sofabed construction particularly 
designed for use with a unitary futon mattress member. The seat and back 
units of the sofabed are hinged together and include floor engaging base 
members for supporting the sofabed when the back is in upright seating 
position as well as when the unit is extended out into sleeping position. 
The assembly provides a combined link and roller mechanism which easily 
moves the back and seat sections from one position to the other while 
providing rigid floor supporting structure members for the two sections in 
both positions.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Futons are cushions which have sufficient padding to eliminate the use of 
springs and are frequently used as a mattress for sleeping on the floor. 
It is apparent that providing a folding seat arrangement is more 
convenient and comfortable for use as a bed than having to remove the 
futon mattress pad from a fixed sofa frame and laying it out on the floor. 
The present invention provides a folding seat framework for supporting the 
futon pad when the same is being used as a seat and then providing a 
simple yet rigid fold-out flat support for the futon when used as a bed 
raised above the floor. 
The enclosed drawings show a pair of rigid end supporting frames F, each of 
which is provided with front legs 5 and rear legs 6 and a top supporting 
arm structure 7 with an intermediate connecting frame member 8. The front 
legs 5 have a front longitudinal crossbar 5a extending therebetween and 
rigidly fixed thereto. The rear legs 6 also have a rear crossbar 6a 
disposed at a higher elevation than the front crossbar 5a and being 
rigidly connecting the end frame units F to form a stationary rigid 
supporting frame assembly. 
A back unit B has center frame member 9 and a pair of end frame members 10. 
All of the frame members 9 and 10 have their lower ends 9a and 10a 
respectively supported on the floor when in upright sofa position as shown 
in FIGS. 1 and 2. A plurality of spaced-apart cross slats 10b extend 
continuously between the two end frame members 10 and across the center 
frame member 9 of the back unit B which is pivotally connected to the end 
frames F by pivot links 12. By running the spaced slats 10b from side to 
side the futon is held against sliding off the sofa unit. 
The pivot links 12 pivotally connect the end members 10 of the back unit B 
with the stationary supporting end frames F as by pivotal connections 12a 
and 12b. The links 12 permit the back frame unit B to swing down from 
inclined sitting position shown in FIG. 2 into horizontal sleeping 
position shown in FIG. 3. A stabilizing roller 15 is rotatably mounted on 
the outside of each of the end frame members 10 of the back B and rolls on 
a track 16a formed by a cleat 16 fixed to the inside of each of the end 
frame members 8. 
A seat frame unit S has a center frame member 17 and a pair of end frame 
members 18. The rear frame members 9 and 10 are respectively connected to 
the frame members 17 and 18 by the pivot pins 18a. The pivot pins 18a are 
spaced upwardly from the lower ends 10a of frame members 9 and 10 which to 
engage the floor when in retracted sitting position to provide direct 
support for the seat. A plurality of spaced apart slats 18b extend across 
the seat units between the end frame members 18 and rigidly connect the 
same. These spaced slats 18b run from side to side and combine with the 
back slats 10b to prevent the futon from sliding off the seat unit. A face 
plate 18d extends above the plane defined by the slats 18b of the seat to 
engage the front edge position of the futon and assists the spaced slats 
in preventing the futon from sliding off the seat section when in use. The 
front ends of the seat frame members 18 have retractable legs 20 pivotally 
mounted thereon by pivot pins 20b. A cross member 20a rigidly 
interconnects the pivoted legs 20, as best shown in FIG. 3 and extends 
outwardly beyond both legs 20 to form stop elements 20c which engage the 
lower edges of the end frame members 18 of the seat S when the legs are in 
retracted position as shown in FIG. 2. The cross member 20a engages the 
top rear edge of the cross bar 5a which extends between the front of the 
end frame F. 
The frame assemblies B and S are shown in retracted sitting position in 
FIG. 2 wherein the member 20a of the leg assembly 20 engages the back edge 
of the top of the crossbar 5a to positively position and anchor the seat 
and back assemblies S and B in sitting position. The rollers 15 also abut 
the back ends of the roller track 16a to combine with the links 12 and 
cross member 20a to anchor the seat and back assemblies S and B in sitting 
position. When it is desired to shift the assembly into horizontal 
sleeping position, as shown in FIG. 3 the front edge of the seat frame 
assembly S is lifted to raise cross-member 20a above the crossbar 5a and 
the seat assembly S is then pulled forwardly. This automatically swings 
the back unit B down into horizontal position and the rollers 15 move 
horizontally forwardly on the track 16a. The forward end of each cleat 16 
has a raised portion 16b to raise each roller 15 and elevate the seat back 
B into flat horizontal alignment with the seat assembly S. This roller and 
link mechanism makes it very easy to shift the seat and back units from 
one position to the other and provides a positive positioning of both 
units in both positions. A pair of elevating support elements 18c engage 
the top edge of the front crossbar 5a and are supported thereon, as shown 
in FIG. 3, to elevate the intermediate portion of the frame units into 
horizontal alignment when the units are in sleeping position. This permits 
the front edge of the seat frame unit to be disposed at a lower elevation 
for sitting position than for sleeping position. The legs 20 will of 
course be swung down into vertical position as shown in FIG. 2 to support 
the front edge of the seat frame unit S when in horizontal sleeping 
position.