US2794493A - Spring base for seat cushions - Google Patents

Description

June-4, 1957 j. s. PLATT 2,794,493

, SPRING BASE FOR SEAT cushion; Filed Dee. 21, 1255s 7 2 ants-sheet 1' INVENITOR. Jai 61 flaff 7 United States atent G SPRING BASE FOR SEAT CUSHIONS John G. Platt, Carthage, Mo., assiguor to 'Flex-O-Lators, Inc., Carthage, Mo., a corporation of Missouri Application December 21, 1955, Serial No. 554,531

2 Claims. (Cl. 155179) This invention relates to new and useful improvements in furniture Seating, and relates more particularly to the spring bases for seat cushions.

The principle object of the present invention is the provision of a spring base for seat cushions having novel means whereby the relative softness or firmness of the cushion may be varied adjustably to suit the preference of the individual user.

' Another object is the provision of a spring base of the character described wherein the relative yieldability of different portions of the same cushion may be adjusted.

A further object is the provision of a spring base of the character described wherein the adjustment of the firmness of the springs is accomplished substantially without variation of the normal tension of the springs, whereby to avoid the overloading, permanent setting-and fatigue of the springs which might otherwise result from the adjustments. These objects are accomplished by supporting the cushion by means of cantilever type springs fixed in the seatframe and extending generally parallel to the cushion surface, and by providing rigid supports beneath said springs at an adjustably variable distance from the fixed ends thereof.

Other objects are simplicity and economy of construction, efficiency and dependability of operation, and adaptability of the spring structure involved to be applied to pre-existing types of seating with a minimum of alteration thereof.

With these objects in view, as well as other objects which will appear in the course of the specification, reference will be had to the drawing, wherein:

Fig. l is a top plan view of a spring base for a chair embodying the present invention, with the upholstery layers omitted, being a sectional view taken on line I--I of Fig. 2, and

Figs. 2 and 3 are sectional views taken respectively on lines II-II and III-III of Fig. 1.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies to the main frame of a chair, shown fragmentarily and including front corner uprights 4 and 6, rear corner uprights 8 and 10, side rail 12 interconnecting and fixed to corner uprights 4 and 8, side rail 14 interconnecting and fixed to corner uprights 6 and 10, and a horizontal back rail 16 interconnecting and fixed to rear corner uprights 8 and 10. Said frame carries a floor-engaging leg 18 at each corner thereof. The back and arm structures of the chair, not shown, may be carried by the corner uprights, but form no part of the present invention.

The seat frame 20 is substantially rectangular in form, comprising a front rail 22 extending between and detachably secured at its opposite ends to front uprights 4 and 6 by bolts 24, a rear rail'26 extending between and detachably secured at its opposite ends to rear uprights 8 and 10 by bolts 28, and a pair of parallel side rails 27 and 29 extending between said front and rear rails and aflixed thereto in spaced apart relation. It will be understood that the specific construction of the main frame and seat frame as shown are exemplary only, except those structural features thereof used and useful in the support and adjustment of the spring elements hereinafter described.

Seat frame 20 carries a plurality of generally planar spring units 30 disposed in vertical planes extending from front to rear of the seat and spaced regularly across the width of the seat. Each of said spring units comprises a single length of spring wire having a horizontal reach 32 disposed above and parallel to the plane of seat frame 20, inwardly and downwardly sloping reaches 34 and 36 connected at their upper ends to the ends of reach 32'by bends 38, outwardly extending horizontal reaches 40 and 42 connected at their inner ends to reaches 34 and 36 by bends 44, the extreme outer end portions of each of reaches 40 and 42 being received in a transverse slot 46 formed in the upper edge of front rail 22 or rear rail 26, as the case may be, and being bent downwardly as indicated at 48 to fit into a vertical socket 50 drilled in said rail. The insertion of the spring ends into sockets 50 prevents the spring units from tilting laterally out of their planes, and the disposition of reaches 40 and 42 in rail slots 46 prevents the spring ends 48 from pivoting in sockets 50. Said spring ends are secured against rising out of said sockets by a pair of bars 52 and 54 laid re-.

spectively along the upper edges of rails 22 and 26 and secured thereto by screws 56.

The central horizontal reaches 32 of the spring units form the supporting surface for the padding and upholstery layers (not shown), said upholstery layers having their edges drawn downwardly and tacked or otherwise suitably secured to the seat frame rails. Reaches 32 are joined together by a pair of cross Wires 58 and 60 disposed respectively at the forward and rearward ends of reaches 32 andextending transversely thereto. Said cross wires are joined to each of the spring units by a suitable clip 62. It will be seen that the end portions of said cross wires are bent into the vertical planes of the outer most spring units 30 for connection thereto, and that the bend portions 38 of the intermediate spring units are bent into the vertical planes of the cross wires for connection thereto. It will of course be understood that additional cross wires could be added intermediate wires 58 and 60 if needed.

It will be seen that each of the reaches 40 and 42 of the spring units constitutes a cantilever spring fixed at one end in the seat frame, and having a free end at the bend 44. Reaches 40 and 42 are also approximately parallel to the seating surface of the cushion and are preferably so installed that this parallelism will occur after whatever pre-stressing of the springs is caused by the installation of the padding and upholstery. The cantilever springs 40, which are disposed along the front edge of the seat and afiixed in front rail 22, are supported by a horizontal bar 64 extending transversely thereto and parallel to front rail 22, and cantilever springs 42 are supported by a horizontal bar 66 extending transversely thereto and parallel to rear rail 26. Each of the springs is supported in a groove 68 formed transversely in the upper edge of the associated support bar. The bottom of each of said grooves is formed arcuately in the plane of the spring unit, in order to support the spring smoothly regardless of the flexure of the spring reach supported therein as best shown in Fig. 2. Each end of each of the support bars 64 and 66 is provided with a tongue 70 (Fig. 3), said tongues being slidably carried in a pair of grooves 72 formed respectively in the inner faces of side rails 27 and 29 of the seat frame.

It will thus be seen that support bars 64 and 66 may be moved adjustably along the length of the cantilever springs 40 and 42 supported thereby, and will vary the '3 effective lengths thereof. The effective length. of the cantilever springs, for practical purposes, is the length thereof between the support bar and the free end of the spring- (at bend 4 l Thus when: the: support barslare; moved inwardly so as. to be disposed at or 'adjacentbends 44, as. in Fig. 2, the cantileverspi'ings '40 and'i willhave; a-minimumeifective l'engtha'nd hence a. maximumijdegfee' of, stiffness, and the seat will have its maximum degree of firmness. Conversely, when thesupport bars- Q64 and 66 aremoved relatively outwardly toward front and rear rails 22 and 26, the effective length andLyieldabiIity of cantilever springs 40 and 42'arefincreased', and the seat will be-relatively soft and yieldable. It is also apparent that support has, 64' and 66 may be adjusted'independ ently, so that the relativeyieldability of the front and rear portions of the sear may be adjusted to the users preference. The adjustment is rapid, and easy, since the bars 64 and 66'are easily accessible fromthe bottom of the chair. g 7

It is of course true that even with the support bars positioned directly beneath bends 44, and thence with the seat having its maximum degree of hardness, the spring reaches 34 and 36 still'provide some yieldability. However, the: adjustability is provided substantially entirely by varying the effective lengths of the spring reaches 40' and 42, and theyieldability of reaches 34 and 36 is con- I sidered of minor importance in this inventiomand they could be of dilferent degrees of rigidity without affecting the. main concepts involved. In fact, insofar as certain of the broader concepts involved are concerned, the portions of the spring units above bends 44 may be considered as mere supporting superstructure which could be of nearly any design. This generalization, however, does not 'apply to the features of the spring structure which provide substantially independent support for the front and rear edges of the seat. I

It is also considered important that the adjustment of the yieldability of the cushion is accomplished substantially without varying the normal tension of the spring units. This eliminates to a large degree any overloading of the springs, or any permanent deformation or fatiguing thereof, which. might occur if the adjustment were accomplished by varying the spring tension.

While I have shown and described 'a specific embodiment of my invention, it will be apparent that many minor changes of structure and operation could be made without departing from the spirit of the invention as defined by the scope of the appended claims.

What I claim as new and desire to protect by Letters Patent is:

l. A spring base for seat cushions, said base comprise...

ing a rigid seat frame, aplurality of spring units each comprising a, length of spring wire and disposed in a vertical plane extending from front to rear of said frame, each of said units having a central portion disposed generally horizontally above said frame, generally horizontal end portions extending horizontally forwardly and rearwardly in the plane of said frame and secured at their extreme ends'in said frame, and angled. portions connecting said end portions to said central portion, the central portions of all of said units forming a cushion supporting surface, and a pair of support members carried by said frame, one of said support members engaging and supporting the forward end portions of all of said spring.

units, and the other of said support members engaging and supporting the rearward end portions of all of said spring units, said support members. being movable horizontally in said frame whereby to. engage said spring units at variable distances from the fixed ends thereof:

2. The structure as recited in claim lwherei'n said frame includes. side rails parallel to the planes of said spring units, and wherein said support members comprise a pair of bars extending transversely beneath said springs and each having its 'ends'disposed slidably in a pair of horizontal grooves formed respectively in the confronting faces of said side rails.

References Cited in the file of; this patent UNITED STATES PATENTS Gibbons Apr. '20; 1948

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