US 2371788 A
Description (OCR text may contain errors)
P. WEEBER March 20, 1945.
CUSHION Filed Aug.
Paul, 11/6656) atenfed Mar. 20, 1945 UNITED STATES PATENT OFFICE This invention relates to cushions, pads, mats,
I and the like, and among other objects aims to provide an article of this character having improved resiliency and other desirable qualities.
The nature of the invention may be readily understood by reference to one illustrative cushion embodying the invention and shown in the accompanying drawing.
In said drawing: M
Fig. 1 is a perspective view of a portion of a cushion.
Fig. 2 is a fragmentary elevation illustrating the assembly of a cushion and showing'a different construction. i
Fig. 3 is a stress diagram on a larger scale illustrating the operation of th cushion in use.
The invention may advantageously be illustrated as embodied in a sponge rubber seat cushion. Within practical limits of economical use of sponge rubber" it has not been possible heretofore to produce cushions which are comfortable for persons of all weights. A cushion com fortable for alight weight person would crush down for a heavy person. On the other hand, if the cushion be satisfactory for a heavy person it will be uncomfortably hard for a light weight person. Coring out of the cushion to provide A portion of the force applied to the upper face of the cushion in the region of the upper tier ofch'annels II is transmitted downwardly through the cushion along diagonal lines directed toward the channels in a lower tier. This is illustrated diagrammatically in Figure 3. Such diagonal forces have a horizontal component which applies tension to the material I4 lying between adjacent channels ID in the lower tier I 3. In effect the upper and lower tiers of staggered channels create a structure comprising a series of triangular trusses indicated by dotted lines l5, Fig.3. The vertical component of the aforesaid diagonal forces tends also to bend or flex the diagonal elements I8 of the truss. Thus, in resisting forces applied to the upper surface of the cushion, the ordinary compressive resili- I ence of the material is supplemented by its reventilating or cooling channels (when the article is used as a seat cushion or the like) increases the softness of the cushion and affords a means by which the desired softness may be attained. However, heretofore cushions of this character were not uniformly soft or resilient. Some regions are harder than others, and after a time the hard regions are perceptible and become uncomfortable. All of these objections might be eliminated by the use of a very deepcushion, but
such a cushion would be prohibitively expensive andotherwise impractical.
In the illustrative cushion-the proper degree of cushioning for persons of different weights is attained without development of objectionable harder and softer regions. 'To prevent undue softness in the region where the cushion is cored out, a truss-like structure is developed which employs elastic properties in the'material not heretofore utilized. The illustrative cushion is provided with a series of longitudinal cores or channels III of elliptical section arranged in staggered relation. In the present instance the cushion is provided withtwo tiers H and I3 of cores, but additional tiers may be used if necessary. These cores or channels may advantageously be formed by coring the mold in which the material is cast. 1
silience in tension and its resilience in bending. A corollary reaction occurs in the material I! lying between each of the channels in the upper tier, such material being placed in compression. The elliptical contour of the top of each of the channels l0 substantially improves the uniformity of deflection over the entire area of the a cushion, as compared with channels of other section.
By utilizing the resilience of the material in tension and bending as well as in compression, excessively soft regions opposite the channels are substantially eliminated. Similarly, the regions between the channels are not relatively harder since they have additional stresses imposed thereon. It is possible with the use of sponge rubber with the arrangement of channels above described to approach the softness of the much .moreexpensive so called foam rubber without crushing down under a person's weight to the point of being uncomfortable. The resilience of the pad may be adjusted for different weights to be cushioned by varying the size'and spacing of the staggered passages.
Communicating with the channels 7 II) are transverse passages l8 which cooperate toventilate and cool the cushion. To prevent complete closing .of the longitudinal channels, auxiliary grooves I9 may be formed in the channels. These remain open and allow ventilation even though the compression of the cushion be such as to close the main channel at one or more points. The grooves I 9, located as they are adjacent the regions of greater rubber thickness,
tend to soften the rubber in these regions, thereby contributing to greater uniformity of defiection.
\ be cushioned.
To facilitate the formation and assembly, the cushion may advantageously be molded in two parts 20 and 2|, being divided along the dotted line 22. This method of manufacture simplifies removal of the mold cores which form the channels I and passages l8. Additional variation in the resilience of the cushion may be obtained by forming sections of different textures of sponge rubber, one being softer than the other. Cushions may be made with two soft sections, two harder sections, or' one soft and one harder section. In the latter case the cushioning action is somewhat different when the soft section is uppermost from that when a harder section is uppermost; a light weight person will use the cushion with the softer section uppermost since it will permit greater local deflection under the lighter weight, thereby contributing to greater comfort.
. In this connection it should be understood that comfortable cushioning involves factors not encountered with static loads or uniform weight distribution. A person's weight is constantly shifting, the distribution of weight is not uniform,
and lack of uniform softness (i; e. lack ofuniformity of deflection of the cushion) eventually causes discomfort. It is important therefore. that the cushion be designed to deflect.substantially under a given weight without, however,
deflecting so far as to crush down and thereby substantially loose its cushioning resilience at any point. Heretofore these characteristics have been possible only in very deep and prohibitively expensive cushions.
Upon assembly, the upper and lower sections 20 and 2! maybe cemented together along their contacting surfaces. Interlocking tongues and grooves 23 and 24 may be formed at various points on the engaging surfaces of the respective upper and lower sections to locate the sections in proper register relative to each other.
It is desirable in practice to fabricate pads with. .a series of different sized cores or channels l0. These, together with sections of difierent sponge rubber textures make possible the selection of cushion of the proper softness for the weight to be cushioned.
The foregoing features may be embodied in cushions, mats, and pads for various uses. For th ordinary seat cushion the assembled sections in unstressed condition should be about 1 /2 inches thick. For deeper mats and pads an additional tier of channels Ill staggered relative to those of the adjacent tier may be employed. For cushioning heavier pressures, less soft, material than the sponge rubber for seat cushions .may be employed and the channels and passage appropriately adjusted to the character of the load to Obviously the invention is not limited to the details of the illustrative cushion since these may be variously modified. Furthermore, it is not indispensable that all features of the invention be used conjolntly since various features may be used to advantage in different combinations and subcombinations.
Having described my invention, I claim:
1. A seat cushion or the like comprising in combination a pad of resilient cellular rubber or like material, said pad having extending therethrough a series of rows of channels of substantial size, the channels in-each row staggered with respect to those ,of the adjacent row, said cushion being subdivided longitudinally into halves along diagonal lines connecting adjacent staggered channels so thata cushion having different rubber textures in the respective halves may be assembled, and means for connecting said halves together.
2. A seat cushion or the like comprising in combination a pad of sponge rubber of limited thickness, said pad havingtherein a plurality of tiers of longitudinally extending parallel channels of substantial section, the channels in one tier being staggered with respect tothose of the adjacent channel so that no portion of a channel of one tier is directly above any portion of a channel of an adjacent tier, said cushion being subdivided longitudinally into halves along diagonal lines extending from channels in one tier to adjacent channels in another tier whereby a composite cushion may be assembled from halves made of sponge rubber textures of a softness appropriate to cushion the load to be imposed thereon.
3. A seat cushion or the like comprising in combination a pad of sponge rubber of limited thickness, said pad having therein a plurality of tiers of longitudinally extending parallel channels of substantial section, the channels in one tier being staggered with respect to those of the adj acent channel so that no portion of a channel of one tier is directly above any portion of a channel of an adjacent tier, and auxiliary grooves of relatively small size in the channel walls to maintain longitudinal ventilating passages in the event said channels be closed by the load imposed onthe cushion.
4. A seat cushion or the like comprising in combination a pad of sponge rubber of limited thickness, said pad having therein a plurality of tiers of longitudinally extending parallel channels of substantial section, the channels in one tier being staggered with respect to those of the adjacent channel so that no portion of a channel of one tier is directly above any portion of a channel of an adjacenttier, said cushion also having a plurality of ventilating passages extending from each channel to the surface of the cushion, and auxiliary grooves of relatively small size closed by the load imposed on the cushion.