Support frame for making furniture

A support frame for use in furniture includes a first pair of end column members and at least one intermediate column member in spaced parallel relationship, a second pair of end column members and at least one intermediate column member in spaced parallel relationship, and at least two rows of horizontal beam members, with beam members disposed between adjacent column members. Openings are provided in the column members and beam member and metal fasteners secure them together, in tension. Additional securement may be achieved by also adhesively securing the column members and beam members together. A decorative covering may be used to encase and decorate the support frame.

BACKGROUND OF THE INVENTION 
The present invention is to a support frame formed from wooden column 
members and beam members secured together, in tension, by a metal 
fastener, for use in making furniture. 
The manufacture of furniture, such as cabinets and bookcases, has gradually 
developed to a point where customized furniture design is expensive and 
time consuming. Since the conventional "slab construction form" of 
furniture production used in all cabinetry since the late 17th century, 
which replaced the old "post and panel" construction, has faults in cost 
and time of construction, a new approach is desired. Instead of building 
furniture frames (or "carcasses") of thin sheets of wood or plywood, the 
use of slats in forming furniture has been proposed. 
The use of slats in forming furniture is shown, for example, in U.S. Pat. 
Nos. 3,722,431 and 4,127,072. 
It is an object of the present invention to provide a support frame for 
furniture that can be used to produce furniture that has conventional 
appearance and style but which is stronger and more durable than 
conventional furniture. 
It is another object of the present invention to provide a support frame 
for furniture that can be used to form customized furniture with cost 
comparable to formation of standard size furniture. 
SUMMARY OF THE INVENTION 
A support frame useful especially in making furniture is formed from a 
plurality of column members, a plurality of beam members, and metal 
fasteners, in tension, which secure the column members and beam members 
together. 
The column members include a first pair of end column members which have 
facing surfaces and at least one intermediate column member disposed in 
parallel relationship and spaced from the end column members, and a second 
pair of end column members having facing surfaces and at least one 
intermediate column member disposed in parallel relationship and spaced 
from the end column members, with the first and second pair of end column 
members and intermediate column members in spaced parallel relationship 
with each other. One of each of the pair of end column members has an 
opening, such as a horizontal slot, in at least the facing surface 
thereof, while the other of each of the pair of column members has an 
opening formed therethrough, and the intermediate column members have an 
opening, such as a horizontal slot, formed therethrough. 
The beam members are provided in at least two rows, with a plurality of 
such beam members disposed in a common horizontal plane, and with each 
beam member disposed between adjacent column members. One row is included 
at/or adjacent a top wall of the column members and a second row at/or 
spaced from a bottom wall of the column members. Each of the beam members 
have a pair of openings, such as vertical slots, formed therethrough. 
The column members and beam members are secured together to form a support 
frame for use in furniture by use of metal fasteners, in tension, which 
passes at least partially through the end column members and is seated in 
the opening therein, and passes through the openings of the intermediate 
column members and beam members. The column members and beam members may 
be secured together solely by use of the metal fasteners, in tension, or, 
additional securement may be provided by adhesively securing contacting 
surfaces of column members and beam members together.

DETAILED DESCRIPTION 
Referring now to the drawings, a support frame 1, for use in furniture, is 
shown in FIG. 1 and has a plurality of column members, a plurality of beam 
members, and metal fasteners, in tension, which secure the column members 
and beam members together. In FIG. 1, which illustrates a bookcase formed 
from a support frame 1, a first plurality of spaced column members 2 is 
provided which include a first pair of end column members 3 (3A and 3B) 
which have facing surfaces 4, and at least one (two shown) intermediate 
column member 5. A second plurality of spaced column members 2' is 
provided which includes a second pair of end column members 3' (3A' and 
3B' ) which have facing surfaces 4' and at least one intermediate column 
member 5' (two shown). The first and second plurality of column members 2, 
2' are disposed in spaced parallel relationship to each other. Each of the 
column members has a top wall 6, a bottom wall 7, side walls 8, and the 
end column members have an outer wall 9 and 9', respectively, in addition 
to the facing surfaces 4 and 4'. One of each of the first pair of end 
column members 3A and one of each of the second pair of end column members 
3A' has an opening 10 in the facing surfaces 4 and 4' thereof, while the 
other of the first pair of end column members 3B and the other of the 
second pair of end column members 3B' has an opening 11 formed 
therethrough (FIGS. 5 and 2A-2D). Each of the intermediate column members 
5 and 5' has at least a pair of openings, such as slots 12, formed 
therethrough. 
A first row of beam members 13 (FIGS. 1 and 3) is provided, which is 
disposed in a substantially common horizontal plane at/or adjacent the top 
walls 6 of the column members 3 and 3', with ends 14 of each of the beam 
members 13 disposed between adjacent column members 3 and adjacent column 
members 3'. A second row of beam members 15 is provided, which is disposed 
in a substantially common horizontal plane at a location at/or spaced from 
the bottom walls 7 of the column members 3 and 3', with ends 16 of each of 
those beam members 15 also disposed between adjacent column members 3 and 
adjacent column members 3'. 
The beam members 13 and 15 have a pair of openings formed therethrough, 
such as slots 17, formed in the bottom wall 18 thereof, adjacent the ends 
14 and 16 respectively. 
A metal fastener 19 is used to secure the end column members 3, 3' and 
intermediate column members 5, 5', and beam members 13 and 15 together as 
a unit. The metal fastener 19, such as a threaded bolt 20 with a head 21 
at one end and a threaded section 22 at the other end is provided with a 
nut 23 that threadedly engages with threaded section 22. As shown in FIG. 
5, the head 21 of the bolt 20 is seated in opening 10 in end column member 
3A and passes through alternating beam members 13 and intermediate column 
members 5 (through openings 17 in the beam members 13 and openings 12 in 
the intermediate column members 5) and into opening 11 in end column 
member 3B. The nut 23 is then threaded on threaded section 22 of the bolt 
20 and by tightening the nut 23, the column members 3 (3A, 3B), 5 and beam 
members 13 are secured together under tension. A similar securement is 
achieved between end column members 3'A and 3'B and the intermediate 
column members 5 and beam members 13 and 15. 
The use of the metal fastener, in tension, to hold the column members and 
beam members together, causes an opposing compression force (in the wooden 
column and beam members) normal to the contacting surfaces of the beam 
members and column members. This creates a "friction connection" at each 
contacting surface. As illustrated in FIG. 6A, an adhesive 24 may be 
applied to the contacting surfaces so as to increase the strength of the 
joint. 
Typically, it has been found that a plurality of spaced column members 
should be provided for every four feet in length of the beam members. 
Where the length of the beam members is four feet or less, only two sets 
of column members are needed, a first plurality or set at one end of the 
beam members and a second plurality or set at the other end of the beam 
members. Where larger beam members are used, at least one set, or 
plurality, of supplemental column members 36 may be supplied, spaced from 
and disposed between the plurality of column members at one end of the 
beam members and the plurality of column members at the other end of the 
beam members, which beam members would be one piece beam members. 
The use of various decorative coverings, such as plywood or a veneer, to 
encase and decorate the support frame is shown in FIGS. 6, 6A, 6B, 6C and 
8. In FIG. 6, a layer of veneer 25 is applied over end walls 26 of the 
beam members 13 and 15 and side walls 8 of intermediate column members 5, 
with the outer surface 27 of the layer of veneer 25 flush with the side 
walls 8 of the end column members 3A and 3B. In FIG. 6A, a recess 28 is 
provided in each of the end column members 3A and 3B and the ends 29 of 
the veneer 25 fit into the recesses 28 with the outer surface 27 of the 
veneer 25 flush with only a portion of the side walls of the end columns 
3A and 3B. FIG. 6B shows the use of spacer column members 30 between end 
column members 3A and 3B and a beam member 13 or 15, with a veneer 25 
covering the side walls 31 of the spacer column members 30, the side walls 
8 of the intermediate column members 5, and the ends 26 of the beam 
members 13, with the outer surface 27 of the veneer 25 flush with the side 
walls 8 of the end column members 3A and 3B. In FIG. 6C, grooves 32 are 
formed in the facing surfaces 4 of the end column members 3A and 3B and 
the ends 33 of the veneer 25 are seated in the grooves 32, with a 
decorative surface 34 formed on the side walls 8 of the end column members 
3A and 3B. While such veneer are shown in FIGS. 6-6C as at the end of the 
support frame with end column members 3A and 3B, the same are typically 
also provided on the end with end column members 3A' and 3B'. 
Another embodiment of the present support frame is illustrated in FIG. 8 
which shows the use of spacer blocks S between some adjacent beam members 
13 and 15, in place of column members, enlarging the spacing between the 
beam members. Such spacer blocks may be used for a more "open" look or in 
cases where all of the beam members are not required for the loads applied 
to the support frame and a savings in material cost is to be achieved. 
In FIG. 9, a decorative covering 25 is shown at both ends of a support 
frame 1, a decorative covering 25A is shown across the top of the support 
frame 1, covering beam members 13, and a decorative covering 25B is shown 
across the top of beam members 15. Also, an additional row 35 of beam 
members is shown with a decorative covering 25C across the top thereof. 
The present invention revolutionizes the concept of a cabinet's carcass or 
support frame and introduces a completely new jointing method. 
The present support frame is an exceptionally strong, materials-efficient 
rigid frame structure which, in one variation, also serves as the 
cabinet's perfectly presentable and attractive exterior without any 
embellishments and, in another variation, serves as a hidden structure 
encased in a decorative covering such as plywood or a wood veneer (which 
covering further increases the unit's strength, rigidity and load carrying 
capacity by creating a composite beam). 
The present support frame enables the advantages of repetitive production 
methods to be applied in the production of unique custom-designed 
cabinets, with hundreds of thousands of possible combinations of width, 
depth, height, geometry, shape, and shelf height. The nature of the 
support frame construction and jointing detail means that it is not 
necessary to "rethink" the design of each different cabinet--as must be 
done in conventional slab construction. Simple adjustments in (a) the 
number of beam members and intermediate column members (to achieve desired 
cabinet depth); (b) the cutting lengths of standard members (to determine 
cabinet width and height); and (c) the number and spacing of openings in 
beam members and column members are all that is needed to create cabinets 
of unique sizes and shapes. 
The present support frame maximizes the inherent strength of the raw 
materials--resulting in materials cost savings (for a given load carrying 
capacity) or greater load carrying capacity and shelf spans (for a given 
number of board feet of materials)--or a combination of the two--i.e. a 
stronger cabinet which uses less raw materials than the conventional slab 
design. 
The present support frame reduces the man-hours of labor required to 
produce a cabinet of any given size and shape and enables the production 
of cabinets to be performed by workers with minimal training and skills. 
The present support frame enables a production facility to be directly and 
immediately responsive to the special needs of each individual 
customer--with no cost premium. The present support frame's simplicity and 
use of standard identical members to build any cabinet enables the shop 
owner to build the exact cabinet any customer desires--in size, shape and 
style. The customer can also select the wood of choice and the exterior 
treatment or decorative covering of choice--with no cost penalties 
associated with "non standard" production. No longer must the customer 
adapt to the manufacturing facility. Now, the manufacturing facility can 
adapt to the customer. The present support frame makes it possible for the 
manufacturing facility to serve each customer--with no premium in cost for 
creating the exact shape and size the customer specifies. 
The present support frame is eminently suited to the use of CADD/CAM 
programming and automation, which will result in additionally reduced 
labor costs. This, however, is not a prerequisite and the manual process 
is ideal for small local production shops. The investment in equipment is 
very small. The only machines needed are a radial arm saw (or table saw) 
and a drum sander. A large capital investment is not required and this 
results in savings in financing costs--and enables committed people 
without a lot of money to start a business. 
Corner cabinets and cabinets of unusual shape (such as trapezoids) are an 
especially well suited use of the present support frame. Corner cabinets 
are simple to build--to any size. Corner units are built by prefabricating 
planks built up of beam members. These planks are cut and slotted on a 
45-degree angle. (This 45 degrees can be varied to any angle to suit any 
special space.) 
Instead of using plywood to build a cabinet's support frame, the support 
frame is constructed of solid wood columns and beams, which are built-up 
laminations of "column members", and "beam members". The beam members and 
column members are all of one standard uniform cross-section. 
For bookcases of constant depth, all column members are identical in length 
and all other aspects, and all beam members are identical in length and in 
all other aspects. This duplication of members makes design, production 
and assembly exceptionally simple and almost error-proof. 
The beam members and column members are connected by exceptionally strong 
"moment connections" (i.e. connections which transfer bending moments, as 
opposed to the joints of the conventional plywood cabinetry which are 
incapable of carrying bending moments). 
The support frame is exceptionally strong and possesses inherent lateral 
stability, without any need to add a front face or back. This support 
frame can be constructed without skilled labor and no special expertise is 
required to design support frames in this way. 
Although the present invention is not restricted to any particular 
materials cross-sectional dimensions, prototypes have used column members 
and beam members of rectangular cross-section, 1.5 inches by 1.0 inches. 
The resulting support frame sides, top and bottom (and interior shelves, 
where applicable) are thus double the thickness of conventional cabinets' 
plywood (or wood) thickness. This results in more than double the bending 
capacity. (The voids between members result in a capacity 50% of that of 
solid 1.5 inches thick lumber. The "moment connections" of the beams to 
the columns result in a reduction in maximum bending stresses due to the 
limitation on the rotation of the beam members at the beam-column 
connections--which approach the rigidity of a "fixed end" connection). 
Although the present support frame is dramatically stronger than a 
conventional cabinet support frame, the same quantities of raw materials 
are used (for a cabinet of the same dimensions). Although the materials 
are twice as deep in section (two times thicker), void spaces are provided 
between members to cut material requirements in half. Adding the materials 
required for the face frame and back of a conventional bookcase, a 
conventional bookcase requires more material than does the present 
construction. By virtue of the spaces between adjacent members, the 
material requirements are exactly one half of those of a bookcase (of the 
same overall dimensions) built of solid lumber of the same thickness. 
The present invention makes designing and building cabinets simple, and 
results in better, stronger, more durable cabinets, while reducing the 
cost of cabinets. 
There are variations of the support frame's basic design concept--all of 
which are encompassed within the present invention. 
1. The connections may be glued or non-glued. (Non-glued units can be 
knocked-down for relocation, transported in compact bundles of members and 
easily reassembled at a new site.) 
The unglued connection relies on friction (generated by the normal force of 
the prestressing bolt) for moment carrying capacity. Although the surface 
area acted upon by friction is large, due to the large number of 
interlocking "fingers" ("members"), the glued connection has greater 
strength and the unglued design is only recommended when customers plan to 
dismantle the units for moving--so that the units take up a fraction of 
the space they take when assembled. 
The connection's great moment carrying capacity (glued or unglued) is 
developed through the large contact area of the beam members and the 
column members. 
The connection provides three load transfer paths: 
a. The prestressing bolt acts as a dowel--and can carry all shear loads in 
dowel action. 
b. Even if the glue did not perform, the friction developed by the 
prestressing bolt would carry all shear loads. 
c. The glue carries shear and bending moments through the joint. 
2. The support frame may be exposed or covered. 
This is a matter of personal preference. Although added strength is 
achieved by the addition of a decorative covering of plywood or solid wood 
veneer, the uncovered support frame is already exceptionally strong. Many 
people aesthetically prefer the open uncovered support frame. It is an 
attractive, functional look, similar to the popular "Mission" style of 
furniture. 
Even with the addition of a 1/4 inch plywood decorative covering to give 
the cabinet the appearance of solid 1.5 inches thick lumber, the materials 
cost are no greater than those of conventionally designed cabinets of the 
same overall dimensions. Structurally, the plywood or veneer and the 
members to which it is glued form a "composite member". This cabinetry is 
"structurally engineered" to get the most out of the raw materials in 
carrying capacity--much as a tree does in nature.