US 3512190 A
Description (OCR text may contain errors)
May 19, 1970 I F. BUFF' 3,512,190
CUSHION CONSTRUCTION Filed July 24, 1967 Tiq.2.
I N VEN TOR. 0 960 50/;
3,512,190 CUSHION OONSTRUCTION Fred Buff, Paramus, N.J., assignor, by mesne assignments, to Tenueco Chemicals, Inc., a corporation of Delaware Filed July 24, 1967, Ser. No. 655,341 Int. Cl. A47c 23/00, 25/00, 27/00 US. Cl. 5-345 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to foamed polyurethane cushions. More particularly it relates to foamed polyurethane cushions which are characterized by a particular structure such that when a body of irregular contour is placed upon its functional surface the surface will be irregularly deflected to substantially reproduce the contour.
The term cushions is used in this specification and in the appended claims in its broadest sense and includes all kinds of articles which are used to impart softness to stools, benches, chairs, lounges, beds and the like. More specifically, it includes pillows, pads, mattresses and similar articles.
It is well-known to produce cushions from foamed polyurethane. Normally these cushions are merely resilient pads of any desired outer configuration in which either the upper or the lower surface may serve as the functional surface. The term functional surface is intended to designate the surface which is faced upward and is to be in contact with the user of the cushion.
There are many advantages to foamed, flexible polyurethane as used in cushions. These are well-known to those skilled in the art. There are also certain disadvantages which the art has striven to overcome. One of these is that foamed, flexible polyurethane has a relatively high load bearing capacity at low load. The result of this is that there is an initial resistance from the cushion when an individual first contacts it. Many manufacturers and users regard initial hardness as highly undesirable.
Another problem which is especially noticeable with polyurethane mattresses is that they manifest the socalled hammock effect. Thus when an individual is re clining on a mattress the torso depresses it a relatively greater amount than the head and feet. This causes the pad to take the shape of a hammock, and also causes the head and feet to be inadequately supported. This hammock-like effect is particularly undesirable when two individuals are reclining on the same mattress and causes both individuals to move toward the center portion of the mattress.
In accordance with this invention a new one piece cushion construction is provided which substantially al leviates the above mentioned disadvantages particularly the hammock-like effect with polyurethane mattresses. The invention provides flexible, foamed polyurethane cushions in which the functional surface is characterized by a plurality of individual segments positioned adjacent each other in contiguous relationship. Each segment is substantially independently movable with respect to adjacent segments.
The segments which may be regarded as adjacent pillars of solid flexible polyurethane foam rising from a common base of solid flexible polyurethane foam are in contiguous or touching relationship. With the exception of the segments on the perimeter of the pad, each segment is surrounded by neighboring segments. It is surprising to find that, despite their contiguous relationship, each segment is capable of acting substantially independently of neighboring segments. It would have been expected that frictional forces at the interface between adjacent segments would cause appreciable response in all of them as a result of a load applied to any one of them. In fact, in prior attempts to solve these problems, adjacent segments have been separated by grooves, slots or wedges so as to avoid interfacial friction. This type of construction is expensive and is wasteful of polyurethane.
The foamed cushions of this invention are formed merely by forming slit lines in the functional surface. These are most conveniently formed with hot Wires which burn their way through a portion of the slab. One wire can be used, but it is most convenient to prepare a frame with a number of fine wires formed to the configuration desired in the final product. With this arrangement the cushion can be formed with a minimum of manipulative operations. Once the out has been made, the natural resilience of the polyurethane allows the individual segments to expand so that adjacent sides come in contact with each other.
One result of this construction is that the initial hardness of the polyurethane is substantially reduced because each increment of the load is resisted by a relatively small surface area. Another is that the hammock-like elfect in mattresses is mitigated since each segment acts 'as a spring which is independent of the other segments.
Thus when a body of irregular contour is placed on the surface of the mattress, each segment will be deflected independently to support proportionately the particular increment of body weight which is applied to it.
The preferred configuration for the functional surface is a checkerboard pattern in which each segment is square shaped i.e. is a rectangle with sides of equal length. This is preferred because it gives satisfactory results and is inexpensive to prepare. The segments can be formed, however, with triangular configurations or with arcuate, suitably circular, peripheries. The cross-section, or average cross-section of the segments can vary from about two inches to about four inches. Normally the depth of the segments will be from about thirty-three to about fifty percent of the total depth of the cushion which, in a mattress, is normally four to six inches. For example, a suitable bed mattress can be prepared in accordance with this invention from a foam slab about fifty-four inches wide by seventy-five inches long and four inches deep, by forming a plurality of square segments each of three inches on the side and two inches deep. It is not essential that all of the segments be of uniform dimensions. In fact, for mattresses with a high degree of comfort it is desirable that each segment on the functional surface under the heavier portions of the body have a larger total area than each segment under the lighter parts of the body. Nor is it essential that all slit lines are of uniform depth. In fact, with some methods of manufac- :ture, it may be more economic or practical to have the slit lines in one direction deeper than those in another direction.
'The polyurethane used in the manufacture of the foamed cushions of this invention can be prepared in the usual manner by reaction between polyethers or polyesters containing free hydroxyl groups and a polyisocyanate such as toluene diisocyanate in the presence of an activator mixture containing water, an emulsifier and an amine catalyst. The foam mixture may contain an auxili- 3 ary foaming agent such as a halogenated hydrocarbon. The polyurethanes used in the invention are conventional materials of the type usually used in the preparation of prior art cushions, but because of the unique, novel construction of the mattress the foam has taken on a new and useful quality.
The invention may be better understood by reference to the accompanying drawings forming a part of the specification wherein:
FIG. 1 is a top view of a mattress constructed in accordance with this invention; and
FIG. 2 is a sectional view taken along line 2-2 of FIG. 1.
Description of the drawings A suitable bed mattress can be prepared in accordance with this invention from a polyurethane foam slab 1, the functional surface of which is divided into segments 3 by slit lines 4 and 5. As aforesaid, the preferred configuration for the functional surface is a checkerboard pattern in which each segment 3 is square shaped. The
' segments can be formed, however, with triangular configurations or with arcuate, suitably circular, peripheries.
As seen in FIG. 2, the slit lines 4 and 5, which define segments 3, may be of unequal depth. With some methods of manufacture, it may be more economical or practical to have the slit lines 4 in one direction deeper than the slit lines 5 in another direction. Normally, the depth of the segments 3 should be from about thirty-three to about fifty percent of the total depth of the slab 1 as described above.
Many apparent variations of this invention are possible without departing from the spirit or scope thereof. *It is specifically intended that all such variations be included within the following claims.
What is claimed is:
1. A flexible, one piece foamed polyurethane cushion, the functional surface of which is characterized by a plurality of individual, compressible segments of solid flexible polyurethane foam positioned adjacent each other in contiguous relationship, each segment being substantially independently movable with respect to adjacent segments, the said segments rising from a common base of flexible polyurethane foam.
2. A cushion as in claim 1 in which the individual segments are rectangular.
3. A cushion as in claim 2 in which the sides of the rectangle are of equal length.
4. A cushion as in claim 1 in which the individual segments are triangular.
5. A cushion as in claim 1 in which the edges of the individual segments are arcuate.
6. A cushion as in claim 5 in which the arcuate edges form a circle.
7. A flexible, one piece foamed polyurethane mattress, the functional surface of which is characterized by a plurality of individual, rectangular compressible segments of solid flexible polyurethane foam positioned adjacent each other in contiguous relationship, each segment being substantially independently movable with respect to adjacent segments, the said segments rising from a common base of flexible polyurethane foam, the total thickness of the mattress being from about four to about six inches, the depth of the segments being from about thirty-three to about fifty percent of the total thickness, the sides of the rectangle being from about two to about four inches.
8. A mattress as in claim 7 in which the sides of the rectangle are of equal length.
References Cited UNITED STATES PATENTS 2,315,391 3/1943 Blair 536l 3,222,697 12/1965 Scheermesser 5-36l BOBBY R. GAY, Primary Examiner A. M. CALVERT, Assistant Examiner US. Cl. X.R. 5-361