US2294706A - Bale of springs - Google Patents

Description

p 1942- 4 F. R. ZIMMERMAN 2,294,706

BALE OF SPRINGS Filed May 8, 1939 Patented Sept. 1, 1942 i1 siren STAT 1 price 3 Claims.

The main object of the present invention is to provide a method for preserving the uniform resiliency of a flat spring ribbon of either the ordinary unbroken type-exemplified in clock springs, or the skeleton type exemplified by wire bent to zig-zag form used extensively in the upholstery art.

A further object of the invention is to so carry out the method of this invention as to facilitate the baling of a plurality of bent fiat springs of the same or different lengths to provide a substantially cylindrical bale thereof wherein the component elements are slightly nested into each other.

It has been the common practice in the art to which the invention relates to form long flat strips of resilient ribbon stock into spiral rolls simulating a fully contracted clock spring with the portions of the flat springs in the innermost portion of the roll of appreciably smaller radius than the outer portions, the radii of the several convolutions of the roll increasing progressively from its inner to its outer portion.

It has been common practice to first form the rolls of the metal strips and then subject said rolled-up strips to heat treating to set the metal at the same time that it is hardened.

Thus when the metal is unrolled and cut into lengths, the pieces first cut from the roll possess a far longer radius of curvature than those out from the inner portion of the roll.

In the upholstery art the fiat springs of given length are initially set on a short radius and are forcibly expanded to a long radius as their ends are suitably anchored to opposite rails of a furniture unit, such as a seating unit, furniture back, or box springs for beds, the said springs being arched over the open spaces between the elements or rails to which the ends of the same are anchored.

The difference in the initial radius of the springs so cut from the roll obviously changes their respective load-resisting characteristics when they are expanded to form the aforesaid arches of equal length and height.

The only advantage in disposing the long strip in clock-spring like rolls is compaction thereof to occupy minimum space and reduce transportation costs and also to effect economy of storage space, but these advantages are outweighed by the aforesaid disadvantages.

In the accompanying drawing, illustrating a bale of springs constructed in accordance with the method of this invention,

wire taken on the horizontal plane of the axis of the bale.

Fig. 2 is a fragmentary detail sectional view of the same on an enlarged scale taken on the line 22 of Fig. 1.

Fig. 3 is a fragmentary transverse sectional view of the bale, on an enlarged scale, taken on the line 3-3 of Fig. 1.

Fig. 4 is an end elevation of a bale -of flat strip or ribbon stock made in accordance with the method of this invention.

Fig. 5 is a fragmentary side elevation of the same partly in central vertical section.

Referring first to Fig. 5, it will be noted that the flat spring or ribbon stock I is wound helically on a light or small pitch about an axis to form a substantially cylindrical bale 2 wherein the ribbon l is disposed in successive coils, each of which overlaps the next preceding coil over substantially half the width of said ribbon stock. In the instance illustrated in Fig. 5, the bale is composed of a single strip or ribbon of said material, but the bale may be composed of a plurality of strips of ribbon stock I to form a plurality of short bales, each of which is nested at one or both ends into or over contiguous similar small bales.

The customary practice in the art is to first bend the ribbon of metal about an axis so that every point in the stock is substantially equidistant from the said axis. Upon completion of a bale of stock of given length, the whole bale is suitably heat treated to harden and set the Fig. 1 is a plan section of a bale of zig-zag ribbon stock while the same is maintained in the condition to which it has been previously bent, as aforesaid.

If the ensuing bale is composed of a single strip of ribbon stock, then given lengths of said stock will be unwound from the bal and cut from the latter for use in the production of furniture units, such as spring assemblies wherein the strips of the ribbon stock are secured at their ends to a suitable frame, as for example, the frame of a chair seat. In so doing, the substantially circular strips of the ribbon stock are increased accordingly in radius to provide relatively shallow arches which span the opening in the frame to which the ends of the strips of stock are suitably secured.

By bending all of the strips and setting them at the same initial small radius, it will be obvious that when said strips are incorporated into a seating unit, for example all of them will offer the same degree of resistance to load and thus provide a composite unit wherein a number 01 said strips are disposed side by side, which is of uniform load-resisting capacity throughout the area occupied by said strips.

In baling the substantial equivalent of flat strips of metal, exemplified by a wire or wires 3 bent to zig-zag form, as clearly illustrated in Fig. 1, the same method of bending the skeleton flat springs thus formed of said Wire to form a helix is followed. Said bale comprises a succession of helical coils 4 of small pitch wherein the opposed substantially cylindrical faces of each coil 3 of said wire are disposed at an incline of very few degrees to the axis of the bale.

In the instance illustrated, for example, the coils overlap each other a distance equal to about half the width of strip of zig-zag wire and in such case, the inclination of the inner and outer faces of the strip to the axis of the bale will be only a very few degrees. The extent of the overlap of each coil of the helix upon the next succeeding coil or convolution may be changed and varied as desired, but should be uniform throughout the length of the bale.

This slight inclination of said inner and outer faces of the strip to the axis of the bale does not in any manner affect relative positions of said flat faces of the strips to become flush with each other when mounted upon a frame, such as a chair seat, as aforesaid, so that both side edges of each strip, when mounted upon a chair seat, or the like, will be horizontally aligned with each other in the direction parallel with the axis of the arc or arch of the several springs so mounted upon a frame.

A further advantage of the structure lies in the fact that by bending the strip or strips to a relatively small radius, compared to that of the arches of a chair seat subsequently formed thereby, a compact bale of the strips is formed which may be of such length as to equal, for example, the width of a freight car or truck in which the bales are to be transported.

Generally speaking, furniture manufacturers order the springs cut to given lengths and to be delivered to them in such lengths. An order may specify one-thousand springs of one length, two-thousand of another, etc. The method of bending and baling the strips is accomplished easily by a machine which also disposes the strips or springs into the nested relation to each other which forms the bale.

In many instances the strips are so short as to approximate in length the circumference of the bale while other strips are of a length equal to several times the circumference of the bale. By bending the strips of all different lengths to the same helical contour and diameter, the baling thereof as well as maintenance of uniform resiliency is facilitated.

I claim as my invention:

1. A substantially cylindrical bale of springs of the type specified comprising a series of armate and slightly and equally helical springs nested consecutively into each other, the average diameter and pitch of all of said springs being the same and the flat faces thereof extending equi-angularly to a common axis.

2. A substantially cylindrical bale of springs of the type specified comprising a series of helical springs of equal pitch nested consecutively into each other, one side of each of said springs being of smaller radius than the other side edge of the same of a distance substantially equal to three times the thickness of the metal of which the spring is composed.

3. A flat sinuous wire spring of helical contour and uniform pitch and average diameter throughout its length and having its fiat faces disposed equiangularly to the axis of the helix formed thereby, the pitch of the latter and the angle of said faces to said axis being such that the inner and outer faces of the spring overlap each other over substantially half the width of the spring.

FRED R. ZIMMERMAN-

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