US2731075A

US2731075A - Spring construction

Info

Publication number: US2731075A
Authority: US
Publication date: 1956-01-17
Anticipated expiration: 1973-01-17

Description

Jan. 1 7, 1956 H. C. FLINT SPRING CONSTRUCTION Filed Aug- 2, 1949 F Tw'ZIVEXi 2,731,075 -Patented Jan. 17, 1956- SPRING CONSTRUCTION Hyland C. Flint, Birmingham, Mich., assignor to American Metal Products Company, Detroit, Mich., a corporation of Michigan Application August 2, 1949, Serial No. 108,133

Claims. (Cl. 155-479) This invention relates to spring constructions embodying a plurality of prearched, sinuous, or zigzag spring strips of the type disclosed and claimed in Kaden Reissue Patent No. 21,263 and, in particular, refers to such a spring per se.

Sinuous spring strips of the type indicated have become increasingly popular in recent years for use in spring cushion constructions because, among other reasons, of the ease with which they can be adapted to provide various cushioning characteristics. For example, as shown in a copending application, Serial No. 89,114, filed April 22, 1949, now Patent No. 2,698,651, issued November 30, 1954 of the present inventor, entitled Zigzag Spring Unit Having a Closed Supporting End,

there are disclosed a number of spring strip constructions which provide varying types of conformability to objects placed thereon. This is accomplished by bolstering up desired sections of the spring strips through the medium of additional resilient supports attached thereto. There are instances, however, where, instead of stiffening the spring strip, as in the invention of the application just mentioned, it is desired to soften the spring.

This, for example, is the case when the convex bodyengaging portion of the spring substantially intersects or is slightly below and facing the rail. In such a case,

limitations on the depth of the spring construction nor;

mally prevent the use of conventional types of resilient supports for the end of the strip and it therefore is necessary to resort to means such as provided by this invention for attaching the strip to the rail in such a manner that the spring is softened.

The general object of this invention is, therefore, to provide means for softening sinuous spring strips of the type referred to.

A more particular object is to provide means for attaching the arcuate seating portion of a sinuous spring to a rail which furnishes increased flexing and softness and also permits the convex side of the seating portion to substantially intersect or face the rail.

These and other objects of the invention are accomplished by a sinuous spring strip construction having a deformable section or buckle adjacent the end which is to be fixed to the cross rail. The buckle is preferably substantially V-shaped and defined by side portions which are movable relative to each other so as to provide the necessary increase in flexing required to soften the spring strip.

Various forms of the invention are shown by way of illustration in the accompanying drawings, in which:

Figure 1 is a side elevation of one form of spring strip embodying the invention which is attached at each end to the usual cross rails that are shown in section;

Fig. 2 is an enlarged view of the portion of the spring strip of Fig. 1 included within the circle 2;

' Fig. 3 is a partial plan view of the spring strip of Fig. 1 and shows the sinuous or zigzag construction; and

Figs. 4, 5, 6 and 7 are views similar to that of F1g. 2

of modified forms of the invention.

The spring strip 1 of Figs. 1 and 2 has a web portion 3 which is supported underneath one end by a conventional outwardly opening V section 5 formed in the spring strip and is attached to the rail 7 by insertion of the straight portion of the last of the adjacent, oppositely presenting loops 9 in a clip 11 of conventional form that is secured to the rail 7. Spacer loops 13 may be provided between the support 5 and the web and also at the apex of the support 5 to increase the depth of the spring construction. .If desired, a helper spring 15 may be clipped at its ends to the web 3 after prearching on substantially the same radius as the web so that it lies in juxtaposition to the strip 1 and thereby increases the stiifness of the central portion of the web 3.

In accordance with this invention, means are provided to increase the permissible flexing, particularly in a longitudinal direction, of the other end or" the spring, this end being attached to the rail 17 in such a manner that the convex upper face of the web or seating portion 3, if extended, would intersect the rail. This end of the spring is rigidly aflixed to the top of the rail 17, preferably by insertion of an entire single loop 9 in clip 19 having a form which is described and claimed in a copending application Serial No. 88,293, filed April 19, 1949, now Patent No. 2,695,658, issued November 30, 1954, of the present inventor, entitled Spring Supporting Clip Having Locking Tongue. Between the member 9 which is mounted in the clip 19 and the web 3, a buckle 21 is formed in the strip 1. In the present embodiment, the buckle comprises an upwardly opening V having its apex below the rail 17. The buckle 21 has an outer side portion or leg 23 which is somewhat shorter than the inner leg 25; for the sake of illustration, it be ing shown as consisting of two loops 9 While the inner leg 25 consists of three loops 9. By virtue of this construction the application of a load P to the web 3 causes the angle included between the legs 23 and 25 to increase. This, of course, increases the effective length of the strip 1 and to this extent decreases its resistance to the load P and increases the strips softness. The expansion of the angle between legs 23 and 25 is accommodated inmost part by twisting or torsion of three rectilinear leg portions of the loop 9, viz., at the point 27 where the leg 25 connects with the web 3, the point 29 where the legs 23 and 25 intersect, and the point 31 where the leg 23 connects with the loop 9 that is inserted in the clip 19. As a result of this twisting, the point 29 is pivoted outwardly about the point 31 to flatten the spring 1 and permit the convex surface of the web 3 to drop well below and face the top of the rail 17.

The spring strip 41 shown in Fig. 4 has a buckle 43 between the web 45 and the endmost loop 47 which is substantially V-shaped and opens downwardly. In this embodiment the rectilinear end portion of the end loop 47 is pivotally secured to the underside of a rail 49 by means of a suitable clip 51 which also has a horizontal shoulder 53 against which the balance of the loop 47 abuts. The outermost leg 55 of the buckle 43 extends more or less vertically from the loop 47 and in this case is of substantially the same length as the inner leg 5?. Upon application of a load to the web 45, the buckle 43 will open as shown in dotted lines in Fig. 4 and the spring will pivot about the clip 51, the combination of these effects providing substantial deflection of the web 45.

In the embodiment of Fig. 5, the spring strip 61 has a web 63 that includes a buckle 65. The buckle 65 may also be V-shaped, but in this case it opens outwardly so that the apex and also a side portion are disposed above a portion of the web 63. The upper leg 67 of the buckle 65 is, in unstressed position, substantially horizontal and connects with a loop 9 that is rigidly secured to the rail 69 by means of a clip 19. The other leg 71 of the buckle 65 extends upwardly and inwardly from a loop "/3 that is formed outwardly and upwardly from the convex surface defined by the web 63. Upon application of the load to the Web 63, the spring 61 is deflected elastically to the dotted-line position of Fig. 5. Expansion of the buckle 65 and twisting of the end portions thereof that are connected to the endmost loop in clip 19 and to the loop 7.3, as well as twisting of the rectilinear loop portion forming the apex of the buckle, provide a substantial increase in the permissible flexing over that obtainable with a continuous web construction, and further permits the convex surface of web 63 to lie well below and face a plane through the front and rear rails.

In the embodiment shown in Fig. 6, the spring strip 81 has a web 83 which is connected through the buckle 85 to an upper and outer portion of the rail 87 by means of a clip 19 which rigidly holds the endmost loop 89. The buckle 85 is V-shaped with the apex above the web 83 and opens downwardly on the rail 87. The outer leg 91 of the buckle 85 lies in the plane of the endmost loop 89, and the inner leg 93 intersects the web 83 in a slightly obtuse angle. As will be apparent from the dotted-line position of the spring in Fig. 6, which shows its conformation after a load is applied thereto, the buckle 85 is in this form contracted or closed by the application of the load. As far as the web 83 is concerned, contraction of the buckle 85 has the same result as expansion of the buckles described in the preceding embodiments, i. e., increases the effective length of the strip 81 and thus decreases the resistance to the load.

In the embodiment of Fig. 7, the strip 101 has a web 103 which is connected to the rail 105 through a U or talon-shaped buckle 107 having its apex or heel portion above the web 103 and embracing the rail 105. The endmost loop of the strip 101 is secured by a clip 19 to the underside of the rail 105. As evidenced by the dotted-line position of the strip 101 (Fig. 7), application of the load causes increased flexing of the strip due to contraction of the buckle 107. In this particular embodiment the buckle 107 also serves to provide a resilient enclosure for the rail 105.

From the foregoing illustration of the various forms of the invention it will be realized that the buckles, by virtue of their ability to expand and contract, endow the strips with an additional amount of deflection under load which results in softening of the strip ends that are adjacent to the rigid rails. While it is ordinarily the endmost portions of the strips which require increased flexing such as provided by the buckles, it will be recognized that they may be used in intermediate portions of the spring, if desired, Without departing from the spirit of the invention. Other forms of buckles, as well as other modifications of the invention, will appear to those in the art; hence it is not desired to limit it to the specific details shown here by way of illustration.

What is claimed is:

1. A sinuous or zigzag spring strip having a convex load-supporting portion and a substantially V-shaped buckle formed in the strip, the apex above the convex portion and the mouth thereof facing the convex portion, the buckle being disposed adjacent to a rear rail element of a support when the spring strip is assembled thereon, the buckle permitting longitudinal extension and vertical deflection of the load supporting portion of the spring strip.

2. A sinuous or zigzag spring strip having a convex load-supporting portion and a talon-shaped buckle formed in the strip with the base thereof above the convex portion, said buckle being disposed adjacent to a rail element of a support when the spring strip is mounted thereon, the buckle permitting longitudinal extension and vertical deflection of the load supporting portion of the spring strip.

3. In a spring seat construction, the combination of a horizontal rear rail, a prearched zigzag spring strip having a load bearing portion extending over a substantial portion of the length of the strip and also having a rear support portion fixedly secured to the rail formed in continuation of the load bearing portion, the rear section of said load bearing portion being substantially no higher than a horizontal plane through the rear rail, said rear support including a deformable buckle enabling said load bearing portion to move lengthwise toward the rear rail as Well as transversely when load is applied thereto, said buckle comprising a portion of the strip bent at an angle to the plane of said rear section and then reversely bent to extend back toward said plane, said buckle portion having an apex located on one vertieal side of the rear section and an expansible and contractible mouth located substantially in the plane of the rear section, said buckle portion being bent at an included angle of more than degrees with respect to the plane of said rear section and extending only rearwardly from said rear section.

4. The invention set forth in claim 3 wherein said apex is spaced vertically above the plane of the rear section.

5. The invention set forth in claim 3 wherein said apex is spaced vertically below the plane of said rear section.

References Cited in the file of this patent UNITED STATES PATENTS 2,125,987 Braun Aug. 9, 1938 2,177,175 Freund Oct. 24, 1939 2,257,633 Bank Sept. 30, 1941 2,285,827 Neely June 9, 1942 2,526,183 Williams et a1 Oct. 17, 1950 FOREIGN PATENTS 206,149 Switzerland Oct. 16, 1939 210,373 Great Britain Jan. 31, 1924