US2155792A - Spring cushion - Google Patents

Description

G. P. JOHNSON SPRING CUSHION April 25, 1939.

Filed Aug. 9, 1937 2 Sheets-Sheet l April 25, 1939. G. P. JOHNSON 2,155,792

SPRING CUSHION Filed Aug. 9, 1937 2 Sheets-Sheet 2 Patented Apr. 25, 1939 UNITED STATES PATENT OFFICE SPRING CUSHION.

Gustave P. Johnson, Waukegan. lil.

Application August 9, 1937, Serial No. 158.029

The present invention relates to spring cushions intended primarily for chairs, although in its broader aspects the invention is also applicable to lounges, beds, cots, and other furniture.

5 Heretofore, the vertically disposed coil springs of the spring cushion seats in upholstered chairs have generally been supported on a fabric bottom composed of a plurality of strips of fabric webbing or of a single piece of webbing secured l to the frame of the chair. Where the chair has considerable use, this fabric webbing usually deteriorates more rapidly than the remainder of the chair structure, and has a tendency to tear loose from its points of attachment to the frame l or to tear at other points of localized strain, thereby permitting some of the springs to sag or become tilted in the spring assembly. Also, it is diflicult to make a durable, lasting attachment of the lower ends of the coil springs to the webbing, and, in addition, the webbing is unsanitary because of the inability to clean the upper surface thereof. Furthermore, .in some instances, where the webbing is arranged in strips, the spring assembly or different rows of the springs may have an objectionable tendency toward side sway.

The principal object of the present invention is to avoid these objections by providing an improved spring cushion characterized by a exible metallic bottom preferably composed of a section of wire netting on which the coil springs are mounted. This wire netting has an inherent resiliency, and still is not subject to deterioration and tearing.

Another object of the invention is to provide such improved spring cushion in which the sec'- tion of wire netting has resilient attachment to the supporting frame through the medium of springs which give an additional resiliency to the entire seat. 'Ihe latter springs are preferably in the form of tension springs which can be readily hooked between the netting and the frame. A full-floating construction can be had by interposing these tension springs between both the front and rear edges of the netting and the frame, or a semi-floating construction can be had by interposing said springs between only one end of the netting and the frame. The entire cushion can be readily adjusted to accommodate users of dierent weights, or to meet any individual desire on the part of the purchaser for a greater or lesser resiliency, by merely adding to or subtracting from the total number of tension springs connecting the wire netting to 5| the frame, which operation can be readily performed without disassembling the spring cushion.

Another object of the invention is to provide an improved spring cushion of this general type in which the wire netting is of such construction that the bottom convolutions of the verti- 5 cally disposed coil springs can be "screwed" or threaded into the netting. This method of attaching the coil springs to the netting can be performed with such ease and facility that it is a great time-saving factor in the manufacture l0 of the cushion, and, in addition, such method establishes a ilxed anchorage for the springs and affords a broad base support therefor.

'I'he relatively large open mesh of the netting enables the upper surface thereof to be readily l5 cleaned with a brush.

Other objects and advantages of the invention will appear from the following detailed description of certain preferred embodiments thereof. In the accompanying drawings illustrating such 20 embodiments: w m H Figure 1 is a plan` view of the spring cushion, the wire netting being illustrated diagrammatically;

Figure 2 is a longitudinal sectional view there- 25 of taken approximately on the plane of the line 2-2 of Figure 1;

Figure 3 is a fragmentary perspective view on a larger scale, showing the wire netting in detail and illustrating the manner in which the verti- 30 cally disposed coil springs are threaded into said netting;

Figure 4 is a fragmentary vertical sectional view through a modified construction;

Figure 5 is a detail sectional view of another 35 modified construction; and

Figure 6 is a fragmentary plan view of still another modified construction.

'Ihe spring cushion comprises a supporting frame which I have illustrated in the form of a 40 box frame il constituting the base of a chair, although I wish it to be understood that any other desired form of frame may be employed. The frame illustrated comprises the two side rails or boards l2, I2, and the front and back 45 railsor boards I3, Il. The corners may be reinforced by suitable corner braces i5, and the supporting legs or feet I6 may be provided with upwardly projecting extensions I5' rigidly secured in the corners between the side and end 50 rails. The side arms and the back of the chair are preferably constructed of separate pieces suitably secured to the side and back rails of the base, although they might be formed as ex'- tensions of these base rails.

The vertically extending coil springs I8 are preferably of the double cone type. The section of wire netting I9 constituting the flexible supporting bottom for these springs preferably has its length extending from front to back of the chair for support on the front and back rails I3 ure 1 but being illustrated in detail in Figure 3.

Such type of netting has a substantial degree -of resiliency or elasticity without deformation, particularly in the direction of its length. One of the features of my invention is the employment of chain link netting in which the mesh, thickness of wire, and interlooped relation of the strands are such that there is a substantial spacing between the upper and lower portions of the wire loops, and all so related that the lower convolutions I8' of the coil springs Il can be readily screwed or threaded into the netting, as illustrated in Figure 3. That is to say, the mesh of the netting is of sufficient size, and the successive loops formed in each strand ISa are so proportioned and shaped, that the upper strand portions or loop portions Ib and the lower strand portions or loop portions I9c lie in separate horizontal planes which are spaced apart vertically a ysubstantial distance, viz, at least equal to the thickness of the wire in the cushion springs Il. By virtue of this construction, the bottom convolution I8' of each cushion spring I3 can be rotated to pass freely in a substantially horizontal plane between the lower surfaces of the upper strand or loop portions Ish and the upper surfaces of the lower strand or loop portions lic without requiring any laborious mechanical operation, such as bending, kinking or otherwise deforming either the spring convolutions or the strands of the netting. It should also be noted that because the cushion springs Il are of the conical type, it follows that the lower convolutions I8' progressively decrease in diameter upy wardly toward the intermediate or upper portion of each spring. Hence, by merely rotating the cushion spring within the netting, the progressively decreasing diameter of its bottom convolution exerts a contracting or tightening action on all of the strands Isa through which said convolution is threaded, which tightening action can easily be made very firm, if desired, thereby establishing a locked or clamped relation between the cushion spring and the netting. so that disengagement of the spring is prevented and, also, so that rattling or metal-to-metal sound is avoided as the load on the cushion spring is shifted or varied. By avoiding the necessity of kinking, bending or otherwise deforming either the spring convolutions or the strands of the netting, the operation of threading or rotating the spring convolutions into the netting can be quickly and easily performed, thereby minimizing the labor item of securing the springs to the flexible bottom; and, furthermore, by such method of attachment the springs are flxedly held against displacement and are given a broad base of supporting contact on the flexible bottom by reason of their engagement with a multiplicity of the strands I 9a at a plurality of widely spaced points. 'lhe substantial degree of vertical spacing which exists between the plane of the upper portion IIlb of each strand loop andthe plane of the adiacent lower portion IIlc of the strand loop, gives a further advantage beyond the advantage of facilitating the threading of the lower spring convolutions I8 into the netting, namely, that of affording a considerable degree of rolling freedom between adjacent strands. That is to say, the side portions iSd-Nd of each strand loop, which establish interconnection between adjacent strands, are shaped or bent on a curvature such that the inner radius of each such side loop portion is at least equal to or larger than the radius of the wire constituting the cushion springs Il. Hence, the contact between the cylindrical surfaces of these side loop portions Ild-Iad is of relatively small area, normallyY approximating that of a point contact,and the side 100D portions of each interconnected pair of loops can be rolled or rocked in either direction relatively to each other. Consequentlv.` the netting can be freely warped or twisted into different planes without permanently stretching or distorting the netting. By thus enabling the netting to adapt itself more readily and more resiliently to a shifting or unevenly distributed load, the flexibility and comfort of the spring cushion is increased.

The above mentioned points of contact between the springs and the strands I9a are indicated in Figure 3 at a, b and c. It will be noted that it is the pressure exerted by the netting edgewise against the coil I8' at these points which determine the limit of the rotation of the spring dur ing its insertion, and that these points of support between the spring and netting are lnecessarily closely adjacent the crossing points, at iSd,

,where the netting strands have their abovementioned rolling or rocking freedom. At the other points the strand portions are by virtue of their spacing not held tightly to the spring. The entire netting is free to flex 'downwardly as the springs 21 yield, as indicated in Figure 4, without being materially restrained bythe lower coils I8' of the several springs. This adds materially to the ilexibility to the seat bottom, as will be readily apparent from Figure 4, for otherwise the ilexibility of the netting wouldbe limited to portions outside the spring bases, and from Figure 1 it will be seen that the spring bases occupy the major portion of the netting.

' In the semi-floating construction illustrated in Figures 1 and 2, the front strand of the wire webbing I9 has its successive loops laced through holes 2l in an attaching bar 22, which is secured by'nails or screws 23 to the front rail I3 of the frame. This laced attachment of the wire webbing to the bar `22 assures an equal distribution of the load transmitted from the webbing to the bar, and also prevents shifting of the loops of the end strand or distortion of this end strand.

Ihe opposite edge of the wire netting has a stiffening rod. 25 extending through the loops of the end strand, the extremities vof this rod being bent rearwardly as indicated at 25' to prevent displacement of the rod. Hooked between this end of the netting and another attachment bar 22a are a plurality of helical tension springs 21, the latter being stretched slightly to impose a continuous tension on the netting. 'I'he attachment bar 22a can be a duplicate of the other attachment bar 22, being secured to the rear frame rail I4 by the nails or screws 23a. and being provided with a plurality of closely spaced holes 2Ia in which the hook extremities at the rear ends of the tension springs are engaged, the hook extremities at the front ends of said springs being engaged over the stiffening rod at points within the loops of the netting.

'Ile connections are established between the upper ends of the compression springs in any suitable manner, although I preferably employ the conventional cords 28, as illustrated. The ends of these cords are anchored to the side and end rails of the frame by the nails or brads 25. When the chair seat is to have a yieldable front edge, the tie connections for the springs disposed along the front edge of the frame are so arranged that these springs are inclined forwardly in order to dispose their upper' ends substantially even with the front edge of the frame. A conventional pad secured over the upper ends of the compression springs I8 is indicated in dotted lines at 3|, and the upholsterlng material which encloses the spring cushion is indicated in dotted lines at 32. An upper cushion, either removable or fixed, is indicated in dotted lines at 33.

By virtue of the spring attachment of the wire netting to the supporting frame, it will be evident that the spring cushion will have the combined resiliency of the compression springs I8 and the tension springs 21. The cushion can be readily adjusted to accommodate different weights or to have a greater or lesser degree of resiliency by adding or subtracting tension springs 21 between the stiffening rod 25 and attachment bar 22a, two such additional springs being indicated in dotted lines in Figure l. It is also possible to distribute the tension springs so as to concentrate a greater part of the tension either at the center or at the edges of the webbing, if such is desired. 'I'he resilient attachment of the wire netting to the frame through the medium of the tension springs 21 prevents the netting from being distorted or stretched out of shape by any sudden or abnormal load. The netting has suficient transverse stiness to prevent objectionable side sway. It will be observed that in the preferred embodiment above described it is only the' front and rear edges of the chain-link netting which have supported attachment to the main frame Il. Hence, the maximum tensile stresses are along substantially parallel lines extending between the front and back edges of the section of netting, which means that these stresses are substantially at right angles to the direction of the transverse wire strands |9a which make up the netting. Therefore, in this preferred embodiment there are no strands in the netting extending in the direction of maximum tensile stress. 'I'his is advantageous because strands extending in the direction of maximum tensile stress resist with their full tensile strength any resiliency of the netting, and if such strands have loops formed therein these loops tend rather quickly to stretch out into a straight line so that the netting quickly assumes a permanent sag. I have found that a greater degree of resiliency is obtained, with less likelihood of the netting assuming a permanent sag, when the side edges of this chain-link netting are left free of connection with the supporting frame Il, so that all of the load is sustained in a direction substantially at right angles to the strands |90, whereby the intermediate portion of the netting is left vfree to contract and expand laterally in its transverse dimension with change of load. However, I also consider it to be within the scope of my invention to interpose relatively light tension springs between the side edges of the netting and the frame so long as the major portion of the load is sustained in a 'direction substantially at right angles to the individual strands Ia. 'Ihe relatively large radius of curvature of the interconnecting side loop portions lad-nd, previously described, also ugments the resiliency of the netting to stresses acting in a direction substantially at right angles to the general length of the individual strands.

My improved spring assembly may be disposed at any desired height relatively to the frame to accommodate frames of different heights or to provide for different heights of the seat in the chair. In Figure 4 I have illustrated the spring assembly lowered the depth of the frame. For such arrangement, the attachment bars 22 and 22a are merely transposed from the top edges to the bottom edges of the front and rear frame rails I3, i4. In Figure 5 I have illustrated the spring assembly as being attached to the frame- |I at a point intermediate the top and bottom edges of the frame. In this arrangement, the attachment bars are in the form of angle bars |22 and |22a which have their vertical flanges secured to the inner surfaces of the front and rear frame rails i3, Il,

As previously remarked, the spring assembly may have a full-oating mounting in the frame I by connecting both ends of the wire netting to said frame through the medium of tension springs 21. Such an arrangement is illustrated in Figure 4, both ends of the netting being provided with stiffening rods 25 to which the inner ends of the tension springs are connected. Such fullfloating mounting disposes the front row of compression springs |8 a greater distance from the front edge ofl the chair, which makes this embodiment more adaptable to a solid-front chair,

. but it will be understood that these front springs might be cocked forwardly or otherwise arranged to dispose their upper ends in proximity to the front edge of the chair where it is desired to employ such mounting in a chair having a yieldable front edge.

In lieu of the stiifening rods' 25, it may be desirable to employ perforated bars or straps 35 similar to the attachment bars 22, 22a. Such construction is illustrated in Figure 6, each bar 35 having a rowA of closely spaced apertures 36 through which the end strand of the netting is laced. The tension springs 21 may be hooked into intermedlately spaced apertures 31, or the apertures 36 may be made sumciently large to alsol receive the hook ends of these springs.

While I have illustrated and described what I regard to be the preferred embodiments of my invention, nevertheless it will be understood that such are merely exemplary, and that numerous modifications and rearrangements can be made therein, and that all or certain features of the invention can also be employed in other furniture such as lounges, beds, cots, etc., without departing from the essence of the invention.

I claim:

1. A resilient bottom unit for a chair, bed, or the like having a frame, comprising a section of wire netting adapted to be carried by said frame and having interlaced strands including vertically spaced upper and lower strand portions, and a plurality of cushion springs each having their lower convolutions extending between the upper and lower strand portions of a plurality of said strands, the vertical spacing between said upper and lower strand portions being at least equal to the thickness of the wire in said cushion springs, whereby said lower convolutions of the springs can be readily rotated into position between said upper and lower strand portions without requiring 'I5 supported by, said frame and including vertically spaced upper and lower strands having inter, laced loops, the portions of the loops which interconnect adjacent strands being formed on a curvature of sufficiently large radius to permit relative rolling motion between said loops-in either direction at their points of engagement. and a plurality of cushion springs having their lower convolutions extending between and rotatably threaded into position between the upper and lower portions of the loops of adjacent strands and interlocked generally edgewise therewith adjacent said points of relative rolling motion, the vertical spacing between said upper and lower portions of the loops being suilicient' to accommodate said springs without requiring; deformation of said spring convolutions or of s'ald loop portions, and to provide for flexing of said netting relative to the springs at said points.

3. In a spring cushion for chairs and the like having a frame provided with front and back rails, a length of chain-link wire netting extending between said rails with the strands of said netting extending transversely of said frame and interlaced together to provide axes of relative flexing movement extending transversely of said frame, a rigid attachment barconnected with one of said rails and to one edge of said netting, a rigid stiiening member attached to the other end of the length of netting, tension springs extending generally at right angles to said strands and connected to the opposite rail and to said stiifening member, and upwardly extending coil springs having their lower ends carried by said wire netting, said netting flexing freely about said transverse axes as said tension springs yield when the load transferred by said coil springs to said netting is taken up by said tension springs.

4. In a spring cushion for chairs and the like having a frame provided with front and back rails, a length of chain-link wire netting extending between said rails with the strands of said netting extending transversely of said frame and interlaced together to provide axes of relative iiexing movement extending transversely of said frame, a rigid attachment bar connected with one of said rails, the loops of the strand at one edge of said netting receiving said attachment bar, successive loops being formed so that the upper and lower strand portions are spaced apart vertically, the portions of the loops which interconnect adjacent strands being formed on a curvature of sumciently large radius to permit relative rolling motion between said loops in either direction at their points of engagement, a rigid stiffening rod extending through the loops of the strand at the other end of the length of netting, tension springs extending generally at right angles to said strands and connected to the opposite rail and to said stiffening rod, and a plurality of cushion springs having their lower convolutions extending between and. rotatably threaded into position between the upper and lower portions of the lodps of adjacent strands and interlocked generally edgewise therewith adjacent said points of relative rolling motion.

5. In a spring cushion for chairs and the like having a frame provided with rails, a length of chain-link wire netting extending between opposite rails with the strands of said netting extending transversely 'of the length of the netting and interlaced together to provide axes of relative flexing movement extending transversely of said netting, a rigid attachment bar connected with each of said opposite rails, a rigid stiiiening rod at each end of the netting and extending through the loops of the strand at that end, tension springs extending generally at right `angles to said strands and connected to each of said attachment bars and to the associated stiffening rods. and upwardly extending coil springs having their lower ends carried by said wire nettingI said netting flexing freely about said transverse axes as said tension springs yield when the load transferred by said coil springs to said netting is taken up by said tension springs.

6. In a spring cushion for chairs and the like having a frame provided with rails, a length of chain-like wire netting extending between opposite rails with the strands of said netting extending transversely of the length of the netting and interlaced together to provide axes of relative flexing movement extending transversely of said netting, means connecting one margin of said netting to one of said rails, a perforated connecting bar, the opposite margin of said netting having its end strand laced through the perforations in said connecting bar, tension springs extending generally at right angles to said strands and connected to the opposite rail and said connecting bar, and upwardly extending coil springs having their lower ends carried by said wire netting, said netting flexing freely about said transverse axes as said tension springs yield when the load transferred by said coil springs to said netting is taken up by said tension springs.

GUSTAVE P. JOHNSON.

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