US2526250A

US2526250A - Zigzag spring construction having central supporting portion

Info

Publication number: US2526250A
Application number: US99952A
Authority: US
Inventors: Jr Frederick C Matthaei
Original assignee: American Metal Products Co
Current assignee: American Metal Products Co
Priority date: 1949-06-18
Filing date: 1949-06-18
Publication date: 1950-10-17
Anticipated expiration: 1967-10-17

Description

0d. 17, 1950 F, c, MATTHAEI, JR 2,526,250

ZIGZAG SPRING CONSTRUCTION HAVING CENTRAL SUPPORTING PORTION Filed June 18. 1949 2 Sheets-Sheet 1 Oct. 17, 1950 c, MATTHAEL JR 2,526,250

ZIGZAG SPRING CONSTRUCTION HAVING CENTRAL SUPPORTING PORTION Filed June 18, 1949 2 Sheets-Sheet 2 /7 77a FANS 5.

Patented oer, 17.1950

' UNITED STATE ZIGZAG SPRING CONSTRUCTION HAVIN CENTRAL SUPPORTING PORTION Frederick C.'Matthaei, Jr., Detroit, Micln, as-

signor to American Metal Products Company,

Detroit, Mich.,

a corporation of Michigan Application June 18, 1949, Serial No. 99,952

i This invention relates to spring constructions embodying sinuous or zigzag spring strips of the .type described and claimed in Kaden Reissue Patent No. 21,263. I

The use of spring constructions of the type referred to has become increasingly widespread in recent years because of their economy of manufacture and also because their inherent nature is such that they may be readily adapted to provide almost any desired combination of resiliency and conformability. The present invention provides a means for exploiting these beneficial natural characteristics in a desirable manner which is especially well suited for back cushion constructions. Thus, in its preferred form, the invention provides a resilient support for the load supporting portion of a sinuous spring strip which, when no external load is applied to the spring construction, exerts a pressure or provides a desired restraint at certain selected points so that a controlled contour is obtained. However, when the spring construction is deformed under 11 Claims. (Cl- 155-179) load, this resistance is spread from the selected I points at which it is originally concentrated to progressively increasing areas of the load supporting portion. This action of the construction is responsible for'very desirable characteristics of conformability to and rather uniform support of objects placed on the spring construction.

These and other results are achieved in the present invention by attaching the separate resilient support which is preferably also of sinuous strip construction, to a third rail that is intermediate the conventional front and rear rails. The invention also provides a clip".construction for facilitating this attachment;

Various embodiments of the invention are illus-. trated in the accompanying drawings in which:

Figure 1 is a section through a springconstruction, with the upholstery removed, embodying the invention;

Fig. 2 is an enlarged view taken on the line 2-.2 of Fig. 1;

Fig. 3 is a section taken on line 3-3 of Fig. 2;

Fig. dis a section taken on line 4-4 of Fig. 2; Figs. 5a and 5b are sections similar to Fig. 1 of a modified form of the invention;

Fig. 6 is a section similar to Fig. l of another modified form of the invention;

Fig. 7 is an enlarged view taken on line 1-1 of Fig. 6; and

Fig. 8 is a section taken on line 8-8 of Fig. "l. The spring construction shown in section in Fig. 1 has the usual supporting frame I that includes bottom and top rails 3 and 5 and interz connecting side members 1. Though only one form is shown, it will be appreciated that a pinrality of laterally spaced sinuous or zigzag spring strips 9 are connected in a suitable manner to the bottom and top rails 3 and 5. These strips are preferably pre-arched in accordance with the teachings of the Kaden Reissue Patent No. 21,263 on a smaller radius than that which they have when secured to the rails 3 and 5. They have end portions H which are bent behind the concave side of the load resisting portion is and serve as means whereby the portion I3. is resiliently connected to the rails through the medium of suitable clips Id. The end portions may be of any desired form, but preferably comprise outwardly opening V sections having arcuate legs with the convex sides facing each other, it being recognized that this construction is well adapted for back cushions.

In accordance with this invention, a third rail 2| is provided intermediate the bottom and top rails 3 and 5. This rail is preferably a, stiff but nonetheless flexible strap as shown in Figs.

1, 5a, and,5b but, if desired, it may be a nonfiexible member such as the outwardly opening channel illustrated in Fig. 6. Resilient means are interposed between the load re:isting portion l3 of the strip 9 and the rail 2| to stiffen the intermediate areas of the portion l3 while at the same time endowing it with desired conformability characteristics. This means preferably comprises a second sinuous spring strip 23.

Various forms of sinuous strip 23 may be employed in the practice of the invention. Preferably, however, the strip 23 has a shape which may be roughly described as elliptical or oblate so that in side elevation the strip'23 resembles a football. Thus, the strips 23 have arcuate portions 25 that are secured to the rail 2 so that the concave sides are facing the concave sides of the load resisting portions l3 of the strips 9. Extending from the arcuate portions 25 are arms that are preferably bent inwardly toward each other from the grneral surface defined by the portions 25, though they may be formed into other shapes if desired, and which serve as n'rans .to

connect the arcuate portion 25 to the load resisting portionl3 and effect a control of the contour of the portion I3 as desired.

In Fig. 1, the arms-21 are secured by a clip 29 to substantially the same point on the load resisting portion l3. In this case the arms are of substantially equal length and are arcuate with the convex side facing the concave side of the portion Hi. In this, as well as in the other forms to be described,'the arms are preferably form so that they must be elastically deformed or prestressed in assembly. Thus, the arms 21 make a larger acute angle with the arcuate portion 23 in the free state as indicated by the dotted lines in Fig. 1, than after assembly of the spring unit with the frame I.

It will be recognized that upon the application of a load to the unit of Fig. 1, the arms 21 tend to flatten out so that the angularity between the arms 21 and the portion |3 decreases in proportion to the load. As the load increases the angularity decreases and progressive engagement occurs outwardly from the clip 23 between the portion i3 and the arms 21 with the result that the initial resistance which was concentrated at the clip is is spread out over a gradually increasing length of the portion I3. This reaction provides a type of conformability which is especially desirable in back cushion constructions.

Figs. a and 5b show that the arms need not be secured to the same point in the portion l3 nor be of the same lengths. The arm 3| is somewhat shorter than the arm 33' and is secured to the portion |3 by a clip 35 which is longitudinally spaced from the clip 31 attaching arm 33 to the portion l3. The arm 3| will thus furnish a slightly stiffer resistance to loads applied in the area of clip 33 than will arm 33 to loads near clip 31 though it will be apparent that both will provide the mechanism of progressive pickup that has just been described in connectionwith the arms 21 of Fig. 1.

Fig. 6 shows a further modification in which there is one arm 3| that, like arms 3| and 33, is bent inwardly toward the arcuate portion 23 and has a convex side facing the portion II, the arm being secured to the portion lit by the clip 32.

The other arm 33, however, has a portion 35 which is bent inwardly toward the arm 3| and then a portion 31 which is reversely bent outwardly and secured at its end by the clip 39 to the portion i3. Preferably, the portion 35 has a convex side facing the portion l3 and the portion 31 has a concave portion which faces the portion l3. The arm 33 provides a different type of resistance than the arm 3|, one difference being its failure to pick up the portion |3 as the load increases, which makes this particular form of spring 23 desirable in certain applications. It is to be noted that the arm 43 is especially capable of providing a greater depth to the spring 23. i. e., it allows a greater distance between the portions l3 and 23 with no sacrifice in the stiffness of the support.

In the modifications of Figs. 1, 5a, and 5b wherein the second or support springs 23 are attached to flexible rail straps 2|, it will be appreciated that the latter furnishes an added degree of resilient support to the portions |-3 of the strips 3. The rails 2| are secured by welding or similar means to the side members 1. If desired, the rail 2| may be arched inwardly of frame I as shown in Fig. 5a, to decrease the required depth of the spring 23.

Various means may be employed to secure the arcuate portions 23 of the springs 23 to the rails 2|.' Preferably, however, pockets 3| are formed in the rails by slitting laterally spaced sections and then upsetting the intermediate portion. The pockets 3| each receive one loop 33 of a sinuous strip 23 and may have the side portions thereof spaced slightly less than the straight portions of the loop so that the latter is slightly compressed and therefore tends to retain itself by spring pressure in the pocket. The pockets, of course,

prevent longitudinal shifting of the spring 23 and as Just mentioned, spring pressure due to compression of the loop 33 may tend to prevent lateral shifting such as takes place if the springs work themselves out of the pockets 3|. Further means may be employed to prevent such lateral shifting. For example, in the rail 2| of Figs. l-5b. upstruck ears 63 are formed on the rail 2| to engage the outsides of the curved portions of the loops adjacent the loop 33. These ears rise only slightly above the surface of the rail so that they do not interfere with insertion of the loops 33 into the pockets. Nonetheless, they effectively prevent, by abutment, undesired removal of the loops from the pockets. Figs. 6-8 show another means for preventing lateral shifting of the springs 23 comprising a dimple 31 formed in the pocket 3| after the loop 63 is inserted therein.

The foregoing description will serve to illustrate to those in the art the manner in which the principles of the invention are embodied into actual spring constructions and some of the advantages thereof. It is evident that various modiilcations may be made in the specific structures shown hence it is not intended to limit the scope of the invention thereto.

What is claimed is:

1. In a spring construction, the combination of a supporting frame including a pair of oppositely disposed parallel rails and an intermediate rail disposed between the first mentioned rails, a plurality of laterally spaced sinuous spring strips having arcuate load resisting portions and end portions bent behind the concave side of the load resisting portions and secured to the first mentioned rails, auxiliary sinuous spring strips between the load resisting portions and the central rail, said central rail having laterally spaced pockets formed therein each receiving a loop of an auxiliary strip to prevent longitudinal shifting of said strips relative to the rail, upstruck ears formed in the rail and engaging the curved portions of loops adjacent to the loop in each pocket to prevent removal of the loops from the pockets and thus lateral shifting of the auxiliary strips, and means securing the auxiliary strips to the load resisting portion.

2. In a spring assembly including a frame having spaced longitudinal members joined by side members. a plurality of zigzag spring strips spanning said longitudinal members providing a load supporting area, second spring strips ellipticallike in shape, each having an arcuate forwardly presenting lower portion from which two reverse- 1y bent arms projecting toward each other extend for attachment to the rearward side of a first said spring strip in longitudinal alignment therewith, and a cross element spanning the side members of the frame between said longitudinal members for engaging the rearmost portion of said second spring strips, said second spring strips supported by said cross element providing support for the central portion of said first spring strips the degree of which is controlled by the position of the ends of said reversely bent arms when attached.

3. In a spring construction, the combination of a supporting frame including substantially parallel spaced-apart supporting rails joined to side rails, a flexible striplike element spanning said side rails between said spaced-apart rails, a plurality of laterally spaced sinuous spring strips having load resisting portions and end portions bent behind the load resisting portions and secured to the spaced-apart rails, and a plurality of ,arched sinuous springstrips each having a load re-' sisting ortion and arms bent therefrom and disposed forwardly thereof to form a second load resisting portion when secured to the load resistof said first spring strips when the resisting portions of the second ing portion first said load spring strips are secured to the striplike element with the spring strips disposed in parallel relation to each other.

lel relation therewith, a plurality of laterally spaced sinuousspring strips having arcuate load resisting portions and end portions bent behind the concave side of the load resisting portions and secured to the spaced-apart rails, and arcuate elongated sinuous spring members having the ends reversely bent to form elliptical elements operatively connecting each load resisting portion of the first spring strips to the striplike element, with the elliptical elements disposed lengthwise of and in vertical alignment with the said spring strips.

5. In a spring construction, the combination of a supporting frame including a pair of oppositely disposed parallel rails and anintermediate rail disposed between the first mentioned rails, a plurality of laterally spaced sinuous spring strips having arcuate load resisting portions and end portions bent behind the concave side of the load resisting portions and secured to the first men-- tioned rails, and sinuous spring members operatively connecting the load resisting portions to the intermediate rail, each'of said members comprising an integralsinuous spring strip having an arcuate portion secured to the intermediate rail with the concave side facing the load resisting portion ofa spring strip and arms bent at the ends of the arcuate portion and extending toward and secured to the load resisting portion.

6. In a spring construction, the combination of a supporting frame including a pair of oppositely disposed parallel rails and an intermediate rail disposed between the first mentioned rails, a plurality of laterally spaced sinuous'spring strips having arcuate load resisting portions and end portions bent behind the concave side of the load resisting portions and secured to the first mentioned rails, and sinuous spring members operatively connecting the load resisting portions to theintermediate rail, each of said members comprising an integral sinuous spring strip having an arcuate portion secured tothe intermediate rail with the concave side facing the load supporting portion of a spring strip and arms bent at the ends of the arcuate portion and extending toward and secured to the load resisting portion, said arms being secured to substantially the same I point-on the load resisting portion.

7. In a spring construction, the combination of disposed parallel rails and an intermediate rail disposed between the first mentioned rails, a plurality of laterally spaced sinuous spring strips having arcuate load resisting portions and end 1 a supporting frame including a pair of oppositely portions bent behind the concave side of the load resisting portions and secured to the first mentioned rails, and sinuous spring members operatively connecting the load resisting portions to the intermediate rail, each of said members comprising an integral sinuous spring strip having an arcuate portion secured to the intermediateing portion of a spring strip and arms bent at toward and secured to the load resisting portion, said arms being arcuate with the convexsides facing the load resisting portion.

8. In a spring construction, the combination of a supporting frame including a pair of oppositely disposed parallel rails and an intermediate rail disposed between the first mentioned rails, a plurality of laterally spaced sinuous spring strips having arcuate load resistin portions and end portions bent behind the concave side of the load resisting portions and secured to the first mentioned rails, and sinuous spring members operatively connecting the load resisting portions to the intermediate rail, each of said members comprising an integral sinuous spring strip having an arcuate portion secured to the intermediate rail with the concave side facing the load resisting portion and arms bent at the ends oi the arcuate portion and extending toward and secured to the load resisting portion, said arms being arcuate with the convex sides facing the load resisting portion and said arms being secured to substantially the same point on the load resisting portion whereby said spring members are generally elliptical or oblate in side elevation.

9. The combination with a frame, of sinuous spring strips made of wire having U-shaped looped portions and carried by said frame, said frame having spaced struck-out pockets each snugly receiving a u-shaped loop of a spring strip, and deflected portions for retaining the loops in the pockets, each of said pockets having upstanding side portions engagin the sides of the loop received in said pocket and a continuous located-with respect to a pocket as to permit the a relative movement of the loop across the deflected portion into the pocket.

10. In a sprin assembly including a frame having longitudinally spaced members joined by side members, a plurality of zigzag spring strips spamiing said longitudinal members providing a load resisting area, second spring strips ellipticallike in shape each having an arcuate central portion from the opposite ends of which. two reversely bent arms projecting toward each other extend and are attached to an intermediate portion of the zigzag strip in alignment with such arms, a cross element spanning the side members of the frame and enga ing the central portions of said second spring strips, said second spring strips supported by said cross element providing support for the central portionv of said first strips, the degree of which is controlled by the position of the ends of said reversely bent arms, means for attaching said reversely bent arms to the first said spring strips, and means for attaching strip, and deflected portions retaining the loops in the pockets, each of said pockets having upstanding side portions engaging the sides of the loop received in said pocket and a continuous laterally extending web joining the tops of said side portions, the deflected portion associated rail with the concave facing the load resist macaw Number being so located with respect to said pocket as 134,490 to permit the relative movement of the 1009 2,185,036 across the deflected portiondurinz insertion into 2,214,138

said pocket. v 5 2,244,469 FREDERICK C. MA'I'IHAEI. Jl. 2,257,883 2,330,908 REFERENCES CITED 2364A99 The following references are of record in the 89 file of this patent: 10 2,480,667

UNITED STATES PATENTS Number Name Date Number 118,782 Biakeney Sept. 12, 1871 574 180,788 Brooks Aug. 27, 1872 15 373,788

8 Name Date Hawk Dec. 31, 1872 Mouse Dec. 28,1939

June 3, 1941 Banks Sept. 90, 1941 Neely Oct. 5, 1943 Wolofeki Dec. 5, 1944 Deutech May 8, 1945 Neely Aug. 30, 1949 FOREIGN PATENTS Country Date Great Britain 0t 1877 Great Britain June 2, 1932