Chair frame

A chair frame that includes a seat portion, a seat back portion extending upwardly from the seat portion, a plurality of legs depending from the seat portion, and bracing extending from the plurality of legs. The seat portion includes a front seat rail, a rear seat rail, and a pair of side seat rails that form a continuous rectilinear configuration for the seat portion. The seat back portion includes a pair of stiles and a back rail, and together with the rear seat rail, forms a continuous rectilinear configuration for the seat back portion. The plurality of legs include a pair of front legs and a pair of back legs. The bracing includes a rear stretcher and a pair of diagonal braces. Each diagonal brace extends from the free terminal end of an associated rear leg to the midpoint of the front seat rail, and together with the rear stretcher of the bracing, forms a triangular configuration for the bracing.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a frame. More particularly, the present 
invention relates to a chair frame. 
2. Description of the Prior Art 
Leaning back in a chair with conventional parallel horizontal bracing to 
strengthen the legs is likely to lead to the fracturing of the joint 
between the seat and the back of the chair. 
There exists, therefore a need for bracing to strengthen the legs of chair 
that will prevent fracturing between the seat and the back of the chair 
when leaning back in the chair. 
Numerous innovations for chairs have been provided in the prior art that 
will be described. Even though these innovations may be suitable for the 
specific individual purposes to which they address, however, they differ 
from the present invention in that they do not teach bracing to strengthen 
the legs of chair that will prevent fracturing between the seat and the 
back of the chair when leaning back in the chair. 
A FIRST EXAMPLE, U.S. Pat. No. 3,901,551 to Wiesner teaches a stressed 
structure assembly providing support for a predetermined maximum weight, 
such as a chair having a framework supporting a seat. Framework members 
are assembled so that each member is in pure compression or tension. 
Framework member configuration is of comparatively light cross section due 
to the absence of necessity for supporting bending stress. The framework 
includes means for supporting the assembly on a surface which is 
conformable to irregularities in the surface. 
A SECOND EXAMPLE, U.S. Pat. No. 4,014,591 to Gittings teaches a collapsible 
chair providing a lightweight, strong, and sturdy chair when unfolded and 
providing a compact elongated structure when collapsed. The collapsible 
chair includes a fabric seat supported in suspended relationship at four 
corners by a frame assembly comprised of a plurality of legs pivotably 
connected together. The frame assembly includes a pair of pivotal crossed 
rear brace legs and a pair of pivotal crossed front brace legs joined by a 
pair of brace leg assemblies which define the opposite sides of the frame. 
The pair of brace leg assemblies each include three pivotally connected 
brace legs, two of these brace legs of each pair of assemblies being 
connected by a pivotable stop link which permits relative pivotal movement 
of these brace legs and provides a means for restraining the three brace 
legs in their proper positions when the chair is in its open position. The 
ends of the pivotally crossed rear brace legs and the ends of the 
pivotally crossed front brace legs are pivotally joined to the side frame 
assemblies by angular brackets which permit simultaneous relative pivotal 
movement of the two connected brace legs about perpendicular axes, and 
thereby facilitating collapse of the chair in two dimensions 
simultaneously to form an elongated compact assembly of nearly parallel 
brace legs. 
A THIRD EXAMPLE, U.S. Pat. No. 4,359,244 to Koehm teaches a folding chair 
having a frame which permits said chair to be easily and conveniently 
folded into a compact configuration that facilitates both the storage and 
transport thereof. The frame of the instant folding chair includes a 
triangular-shaped seat support structure and an arrangement of legs that 
are spaced relative to one another in positions that correspond to the 
vertices of a triangle. By virtue of particular coupling assemblies, the 
structural members of the folding chair of the present invention are 
adapted to be moved in one or both of two perpendicular directions. 
Accordingly, the chair may be folded so that the structural members 
thereof can be arranged in substantially parallel alignment with one 
another and generally in a single plane. 
A FOURTH EXAMPLE, U.S. Pat. No. 4,585,270 to Singer teaches a substantially 
rigid support structure for a piece of furniture, having a pair of 
transversely spaced struts in substantially fixed relationship to each 
other, the axes of the struts being inclined with respect to the 
horizontal, an integral rigid member having two upper ends spaced from 
each other and two lower ends spaced from each other and being oppositely 
inclined with respect to the horizontal and positioned intermediate the 
struts, and a plurality of tension members interconnecting the struts and 
the rigid member to form a substantially rigid structure. 
A FIFTH EXAMPLE, U.S. Pat. No. 4,614,378 to Picou teaches a portable 
reversible chair apparatus with pivotal connections enabling the device to 
be converted from a "posture" chair configuration to a conventional chair 
configuration simply and quickly. While the device is in the "posture" 
chair configuration adjustments are possible that allow users of different 
size to select the seat angle and the seat to knee rest distance which is 
most comfortable for them. The knee rest is designed to flex in the 
vertical plane allowing the seated user to shift weight and position 
comfortably and safely. The critical joints of the chair pivot thus 
eliminating racking of joints. Rigidity is derived from triangulation 
rather than from the size of the joints. The device is very stable due to 
its large base and sits well on an uneven surface because it rests on 
three points rather than the traditional four. 
A SIXTH EXAMPLE, U.S. Pat. No. 4,652,047 to Chan teaches a folding chair 
provided with 8 rods, 4 of which stand vertically a distance apart 
defining the four corners of the chair and four of which are diagonally 
crossed and pivotally secured to each other near their midpoints. The 
lower end of each diagonal rod is connected to the lower portion of a 
vertical rod and the upper end of the diagonal rod is connected to the 
upper portion of the vertical rod located at the corner diagonally 
opposite the first vertical rod. A seat bottom comprised of flexible 
material and two bracing rods is supported at four corners where the upper 
ends of the diagonal rods meet the vertical rods. Arm and back supports of 
a flexible material are supported by portions of the vertical rods 
extending upward beyond the seat level. Each vertical rod is connected to 
a diagonal rod in two locations. In the first embodiment, one connection 
is a releasable joint and the other connection is pivoted joint. In the 
second embodiment, two pivoted joints on each vertical rod are allowed to 
move towards and away from each other by means of an expanding and 
contracting rod. Both of these constructions permit the chair to be 
collapsed into a compact linear storage configuration in which the 
diagonally crossed rods pivot into a position alongside one another while 
the vertical rods assume a position alongside the diagonal rods. 
A SEVENTH EXAMPLE, U.S. Pat. No. 5,718,473 to Lynch, Jr. teaches a folding 
chair that comprises a front, scissors-like X-structure formed by two 
pivotally coupled rigid members, the lower ends of which form front feet 
and the upper ends of which form front seat corners of the chair. Rearward 
the scissors structure, and inverted Y-structure includes a pair of 
downwardly depending rear legs diverging from a central hinge to form rear 
feet and a stile pivotally coupled to the hinge and extending upwardly 
opposite the legs. Two spindles link the front feet to an apex coupled to 
the hinge by a tether, and two lateral braces link the rear feet to the 
front sear corners, the braces and the spindles being pivotally coupled 
together where they cross. The stile opposite the hinge includes a 
transverse rail from which is suspended a hammock seat extending downward 
to the front seat corners on the scissors structure. The chair folds to a 
tight bundle for carrying, the hammock seat doubling as a shoulder sling. 
The chair quickly deploys by spreading the front feet, thereby causing the 
rear feet to spread apart and to extend rearwardly from the front feet. 
The stile, folded downwardly between the rear legs for carrying, pivots 
upwardly at the hinge and latches into place to support the upper end of 
the hammock. 
It is apparent that numerous innovations for chairs have been provided in 
the prior art that are adapted to be used. Furthermore, even though these 
innovations may be suitable for the specific individual purposes to which 
they address, however, they would not be suitable for the purposes of the 
present invention as heretofore described. 
SUMMARY OF THE INVENTION 
ACCORDINGLY, AN OBJECT of the present invention is to provide a chair frame 
that avoids the disadvantages of the prior art. 
ANOTHER OBJECT of the present invention is to provide a chair frame that is 
simple and inexpensive to manufacture. 
STILL ANOTHER OBJECT of the present invention is to provide a chair frame 
that is simple to use. 
BRIEFLY STATED, YET ANOTHER OBJECT of the present invention is to provide a 
chair frame that includes a seat portion, a seat back portion extending 
upwardly from the seat portion, a plurality of legs depending from the 
seat portion, and bracing extending from the plurality of legs. The seat 
portion includes a front seat rail, a rear seat rail, and a pair of side 
seat rails that form a continuous rectilinear configuration for the seat 
portion. The seat back portion includes a pair of stiles and a back rail, 
and together with the rear seat rail, forms a continuous rectilinear 
configuration for the seat back portion. The plurality of legs include a 
pair of front legs and a pair of back legs. The bracing includes a rear 
stretcher and a pair of diagonal braces. Each diagonal brace extends from 
the free terminal end of an associated rear leg to the midpoint of the 
front seat rail, and together with the rear stretcher of the bracing, 
forms a triangular configuration for the bracing. 
The novel features which are considered characteristic of the present 
invention are set forth in the appended claims. The invention itself, 
however, both as to its construction and its method of operation, together 
with additional objects and advantages thereof, will be best understood 
from the following description of the specific embodiments when read and 
understood in connection with the accompanying drawing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the figures, in which like numerals indicate like parts, and 
particularly to FIG. 1, the chair frame of the present invention is shown 
generally at 10. 
The configuration of the chair frame 10 can best be seen in FIGS. 1-5, and 
as such, will be discussed with reference thereto. 
The chair frame 10 comprises a seat portion 12, a seat back portion 14 
extending upwardly from the seat portion 12, a plurality of legs 16 
depending from the seat portion 12, and bracing 18 extending from the 
plurality of legs 16. 
The seat portion 12 comprises a front seat rail 20 that has a pair of 
terminal ends 22 and a midpoint 24 that is midway between the pair of 
terminal ends 22 of the front seat rail 20. 
The seat portion 12 further comprises a rear seat rail 26 that has a pair 
of terminal ends 28 and is spaced behind the front seat rail 20 of the 
seat portion 12. 
The seat portion 12 further comprises a pair of side seat rails 30. Each 
side seat rail 30 of the seat portion 12 extends from an associated 
terminal end 22 of the front seat rail 20 to an associated terminal end 28 
of the rear seat rail 26 so as to form a continuous rectilinear 
configuration for the seat portion 12. 
The seat back portion 14 comprises a pair of stiles 32. Each stile 32 of 
the seat back portion 14 extends upwardly from an associated terminal end 
28 of the rear seat rail 26 to a terminal end 34. 
The seat back portion 14 further comprises a back rail 36 that extends from 
the terminal end 34 of one stile 32 to the terminal end 34 of the other 
stile 32, and together with the pair of stiles 32 of the seat back portion 
14 and the rear seat rail 26 of the seat portion 12, forms a continuous 
rectilinear configuration for the seat back portion 14. 
The plurality of legs 16 comprise a pair of front legs 38. Each front leg 
16 depends from an associated terminal end 22 of the front seat rail 24. 
The plurality of legs 16 further comprise a pair of rear legs 40. Each rear 
leg 40 depends from an associated terminal end 28 of the rear seat rail 24 
to a free terminal end 42, and is collinear with an associated stile 32 of 
the seat back portion 14. 
The bracing 18 comprises a rear stretcher 44 that extends from the free 
terminal end 42 of one rear leg 40 to the free terminal end 42 of the 
other rear leg 40. 
The bracing 18 further comprises a pair of diagonal braces 46. Each 
diagonal brace 46 of the bracing 18 extends from the free terminal end 42 
of an associated rear leg 40 to the midpoint 24 of the front seat rail 20, 
and together with the rear stretcher 44 of the bracing 18, forms a 
triangular configuration for the bracing 18. 
The triangular configuration effectively triangulates the seat portion 12. 
Upon tilting back on the pair of rear legs 40, the pair of diagonal braces 
46 compress by virtue of the seat portion 12. The joints between the front 
seat rail 24, the diagonal braces 46, and the pair of rear legs 40 are 
strengthened by being forced together. This prevents the seat portion 12 
from breaking downwards at its critical joint with the seat back portion 
14. The triangular configuration also prevents wracking (side-to-side 
twisting) of the seat portion 12. The rear stretcher 44 limits the effect 
of someone tilting the chair to the side while seated. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of 
constructions differing from the types described above. 
While the invention has been illustrated and described as embodied in a 
chair frame, however, it is not limited to the details shown, since it 
will be understood that various omissions, modifications, substitutions 
and changes in the forms and details of the device illustrated and its 
operation can be made by those skilled in the art without departing in any 
way from the spirit of the present invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute characteristics of the 
generic or specific aspects of this invention.