US 3633228 A
A pocket spring upholstery assembly comprised of helical springs each encapsulated in a shell of flexible foam plastic and all mutually interconnected by an integral web of the same material. The web has a thickness less than the axial heights of the springs permitting independent movement between the springs under normal load.
Description (OCR text may contain errors)
United States Patent  Inventor Milton Zysman Toronto, Ontario, Canada Appl. No. 30,890
[  Filed Apr. 22, 1970  Patented Jan. 11, 1972 Primary Examiner-Casmir A. Nunberg Att0rneyLeon Arthurs .n h r mm &S
cu mo FF 6 e n g spring upholstery assembly comprised encapsulated in a shell of flexible foam terconnected by an integral web of b has a thickness less than the axial permitting independent movement d a l d m r m .m w a V. d fl fl mm n .K a .lU cau s Oe o tm A rer .imflmmw TP e dm h ln 0 wam n m ka mw m w m fhMee AoPt-nb 3 0 m SIN/5.1 BWSH Lm 5 2 n u H4 /6 .mn h, Hm HU "7 n Y m m mm n L "W B n M E s n "h S u m m A n n F N u T m m m3 mm u n w m m m m m P m m m U ,m m & s n mm m 8 C R M P L .m S9U h F 1 1 1 4 2 1 0 U 5 U n t PATENTEB JAN] 1:972 3,833,22
INVENTOP MlLTON ZYSMHN ATTORNE SPRING UPHOLSTERY ASSEMBLY This invention relates to a spring upholstery assembly suitable for use in bedding, chair seats and backs, and like articles of furniture.
Prior art spring upholstery assemblies as used, for example, by the bedding industry in the production of mattresses have included interconnected coil spring assemblies wherein adjacent springs have been connected adjacent their ends and/or intermediate thereof by stringers or hog rings and have also included what have become known as pocketed springs. Some pocketed spring assemblies have been characterized in that adjacent springs in the assembly have not usually been connected together at their ends or intermediate thereof by the conventional hog rings but have only been interconnected by interstitching between adjacent fabric pockets within which the individual springs are located. Also known in the prior art are mattresses constructed of a foamed elastomeric material some of which have been provided with metal coil springs totally embedded therein. However, such mattresses comprised of a combination of metal coil springs embedded in a foamed elastomer have not attempted to emulate the various advantages sought by a pocketed spring mattress, which advantages have included attempts to provide an independent spring action as between adjacent springs of the assembly. That is to say, a pocketed spring assembly generally seeks to provide a structure wherein any one spring, or group of adjacent springs, may be deformed into compression without unduly disturbing adjacent uncompressed springs of the assembly.
It is accordingly a broad object of the present invention to provide a spring upholstery assembly having the advantageous characteristics generally sought to be provided by a pocketed spring assembly but which utilizes a foamed elastomeric encapsulation for the springs proper dispensing with the fabric type of pockets of prior art spring assemblies.
It is a further object of the invention to provide such a spring upholstery assembly wherein the foamed elastomeric material serves to support and maintain metal coil springs of the assembly for action independently one of another without significant interference with the inherent spring characteristics. However, it is a related object of the invention to provide such a spring upholstery assembly wherein, if desired, the inherent spring characteristics may, in fact, be modified by the encapsulating foamed elastomer by selecting a foam of appropriate density.
It is a yet further object of the invention to provide a spring upholstery assembly as aforesaid wherein the individual coil springs constituting the assembly may expediently be interconnected only by the material of the encapsulating foamed elastomer intermediate the ends of the springs for procuring an independent spring action as between adjacent springs of the assembly.
In a preferred form of the invention, there is provided a spring upholstery assembly including a plurality of coil springs located in side-by-side relationship, each of which is encapsulated in a foamed elastomeric material and wherein each spring proper is interconnected to an adjacent spring by the said encapsulating material at positions intermediate the ends of the springs, the said ends, at least, of each spring being free for independent movement relative to the ends of adjacent springs.
Each encapsulated spring is preferably of barrel-shaped configuration, the largest diameter parts of which are interconnected to adjacent encapsulated springs and it is also preferred that the interior of each encapsulated spring is cored whereby each spring may be freely compressed without any significant interference from the encapsulating material. Furthermore, it is preferred that the complete encapsulated spring assembly be cast as a unit from a foam plastic material such as flexible urethane.
Other objects of the invention will become apparent from the hereinafter following description of the elements, parts and principles thereof given herein solely by way of example with reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views and wherein:
FIG. 1 is a partly sectioned top perspective view of a mattress incorporating the spring upholstery assembly of the invention;
HO. 2 is a top plan view, partly in section, of a row of encapsulated springs of the instant spring assembly, and
FIG. 3 is a side elevation, partly in section, of a part of the instant spring assembly.
A spring upholstery assembly in accordance with the invention may take the form of the mattress M illustrated herein in the accompanying drawings wherein the desired resilience and support is primarily imparted to the mattress by a plurality of side-by-side metal coil springs 10, each encapsulated in a resilient elastomeric material 12 forming a pocket P for the spring 10 and the springs being resiliently interconnected together at 14 in such manner as to support one another and whereby each spring 10 may act substantially independently of its immediate neighbors.
It is worth noting at this juncture that the elastomeric material 12, which is preferably a flexible foamed urethane, may be of sufficiently low density that, despite the encapsulation of the springs 10, it need not contribute significantly to the actual spring action. That is to say, the inherent characteristics of the springs 10 may be substantially unimpaired by the encapsulating material 12 but, at the same time, since it is expedient that the resilient interconnection 14 is comprised of a web of the encapsulating material integral therewith, it should be realized that the said material must be of sufficient density to maintain the springs 10 in side-by-side relation in their desired upstanding position relative to one another.
Of course, the foregoing remarks do not preclude the possibility of selecting a density for the encasing material 12 which is greater or lesser as between different types of spring upholstery assembly so that the encapsulating material 12 can, in fact, have some effect on the spring characteristics, However, despite the foregoing, it may be generally preferred that the encasing material characteristics do not, in fact, contribute significantly to the overall spring action.
Thus, in a spring upholstery assembly, according to the invention, variations in resilience of the individual pocketed springs as between one such assembly and another may conveniently be accomplished by selecting appropriate springs proper. For example, the springs 10 illustrated herein may be chosen to be heavy-duty springs (as represented at 10a in FIG. 3) whereby the resilience of each pocketed spring is stiffened providing a firmer support as compared with the lighter gauge springs illustrated at 10.
As illustrated herein, each spring acts independently of its neighbors in the general manner of a pocketed spring by virtue of the fact that adjacent springs 10 are only interconnected intermediate their ends as at 14 whereby free independent movement of any one spring relative to another is procured. Such an independent action as aforesaid is obtained, in the embodiment illustrated herein, by encapsulating each spring in a substantially barrel-shaped cored enclosure, the largest diameter part of which is integrally connected to the encapsulating material of the adjacent springs by the aforesaid web connection 14. Thus, adjacent pockets P are interconnected only at their central portions by the web 14; there being no further interconnection such as by hog rings or the like between the springs proper 10.
As illustrated in FIG. 3, the web interconnection 14 has a length which is approximately equal to one-third of the overall axial length of each pocket P. However, should it be desired to vary the overall characteristics of the spring assembly, it may be desired to vary the length of the web 14 between certain limits as illustrated diagrammatically herein in FIG. 3 by full and dotted outline of the web 14. It should also be noted herein that the thickness of the encapsulating material 12 around adjacent springs 10 combined with the barrel-shaped configuration of each pocket P enables the springs proper l0 to be spaced a finite distance apart from one another. Such an arrangement precludes the possibility of adjacent springs from coming into contact with one another under compression whereby the possibility of inadvertent interlocking between adjacent springs 10 is obviated; such an arrangement also contributing in some part to an effective soundproofing of the overall spring assembly.
It is preferred that each pocket P is fully cored from one end to the other as will be clearly seen from FIGS. 2 and 3 of the drawings. Such a construction further enables compression of each spring 10 without significant contribution to the spring action from the encapsulating material 12 since said material is able to be compressed outwardly on both sides of the spring convolutions as the spring 10 is compressed and the convolutions brought closer together. Since it is desired that each spring 10 be fully supported by the encapsulating material 12, it is expedient that the said spring 10 in each pocket P be completely invested by the material 12; that is to say, the material should enter between the spring convolutions and fully encapsulate them both radially inwardly and outwardly thereof.
Such investiture of the spring convolutions is conveniently attained by casting the elastomeric material 12 comprising the spring encapsulation and interconnections 14 in situ in a mould which already contains the springs proper 10. Alternatively, interconnected pockets may be cast in a suitable mould and the metal springs 10 then inserted within the cored pockets. However, with utilization of the latter technique, the springs 10 would have to be spirally twisted to reduce their overall diameter before insertion into their respective pockets, subsequent release of the springs enabling them to attain their unstressed condition with consequent radial expansion thereof causing them to press into the interior pocket sides of the cast material effectively to encapsulate the spring convolutions as desired.
It will be appreciated that either of the above techniques enables the spring upholstery assembly to be produced as a single-composite unit or, alternatively, it may be cast in sections for subsequent adhesive interconnection. lt is also worth noting that, since the only interconnection between adjacent pockets P is by the integral web 14, scrap sections of a cast assembly may be cut out and a new section adhesively secured into position thereby reducing the total amount of waste per cast unit.
In the mattress embodiment described and illustrated herein, the mattress M would normally be completed by the provision of a firm edging and ticking cover and also top and bottom pads between the ends of the pockets P and the cover. In this connection, it is contemplated that the aforesaid firm edging may be cast integrally with the composite spring assembly and formed of a foam material which is of a somewhat higher density than the encapsulating material 12 and consequently more rigid to provide firm edge support to the mattress M. Also, in this connection, it may be noted that the instant construction, being comprised of a plurality of interconnected pockets P, lends itself to the casting of a variable density encapsulating material 12 throughout the spring assembly as a whole since the mould for each pocket P would be of substantially cup-shaped configuration initially retaining the casting material therein without substantial flow to adjacent cup moulds prior to the actual foaming step.
A further advantage of the composite spring upholstery assembly according to the instant invention is that, since the only interconnection between adjacent springs 10 is by means of the resilient web connection 14, the assembly as a whole may be flexible greatly facilitating its ready transportation from place to place and also facilitating its storage in a flexed condition such as may be required, for example, in a folding bed assembly.
Also, it is contemplated that top and/or bottom pads may be provided integral with the spring upholstery assembly; such pads being cast of a similar foamed elastomeric material to the encapsulating material 12. Such integral pads need not detract from the independent spring action contemplated by the invention since the pads may be of an extremely low density foam and readily stretchable so that only localized deformation thereof would occur when any one or a localized group of the pockets P was depressed.
Thus there is provided, by the instant invention, a spring upholstery assembly including a plurality of helical upholstery springs assembled in erect side-by-side spaced-apart relation with one another; a resilient web integrally interconnecting said springs and holding them in said assembly, the web thickness being less than the axial heights of the springs whereby portions of said springs project through said web; and resilient investment of the said projecting spring portions merging integrally with said web, said invested projecting spring portions being hollow over at least a part thereof; the resilience of said investment being insufficient to prevent compression of said projecting spring portions independently of one another under normal load but being sufficient nevertheless to restrict deflection thereof out of the erect sideby-side relation aforesaid.
Also, and as illustrated herein by chain-dotted line in FIG. 3, each web interconnection 14 may extend continuously through the interior of the encapsulated springs which it joins together. Such an arrangement will provide an opposed pair of hollow interior cavities at the respective ends of each spring without, of course, detracting from the independent characteristics of each spring in the assembly as hereinbefore described.
l. A spring upholstery assembly including:
a plurality of helical upholstery springs respectively invested in a resilient elastomeric material and assembled in erect side-by-side spaced-apart relation with one another;
a resilient web merging with the investment of said springs integrally interconnecting and holding them in said assembly, the web thickness being less than the axial heights of the springs whereby at least one end of each said spring projects through said web in detached relation to the ends of adjacent springs;
said invested projecting spring ends being hollow over at least a part thereof; the resilience of said investment being insufficient to prevent compression of said projecting spring ends independently of one another under normal load but being sufficient nevertheless to restrict deflection thereof out of the erect side-by-side relation aforesaid under said normal load.
2. A spring upholstery assembly as claimed in claim 1 wherein:
said investment encapsulates each respective spring in the form of a generally cylindrical hollow shell extending axially of at least a part of said spring.
3. A spring upholstery assembly as claimed in claim 2 wherein:
said investment extends over the complete axial dimension of each respective spring.
4. A spring upholstery assembly as claimed in claim 3 wherein:
said web interconnects the said springs intermediate their ends.
5. A spring upholstery assembly as claimed in claim 1 wherein:
said investment on each spring has an exterior configuration of generally barrel-shaped form tapering from the ends to a central zone thereof and said web interconnects said central zone, at least, of adjacent springs.
6. A spring upholstery assembly as claimed in claim 1 wherein:
said web and investment are formed of a material having a resilience sufficient to modify the inherent characteristics of the springs during compressive movement thereof under load.
7. A spring upholstery assembly as claimed in claim 6 wherein:
said material comprising said web and investment is a flexible foam plastic. 8. A spring upholstery assembly as claimed in claim 1 wherein:
said web extends continuously through the said assembly of 5 springs providing an opposed pair of hollow interior cavities at the respective ends of each spring.