Spring Assembly

Abstract

A coiled spring structure comprising a wire frame to which there are attached spaced pairs of longitudinally and transversely extending wires providing at their intersections end supports for the ends of coiled springs and coiled springs having end loops provided with diametrically disposed, reversely bent segments adapted to be sprung into engagement with the wires at the seats.

Parent Case Text

This application is a continuation-in-part of my pending application Ser. No. 97,733, filed Dec. 14, 1970, now U.S. Pat. No. 3,662,411.

Description

BACKGROUND OF THE INVENTION

In my copending application Ser. No. 38,266, filed May 18, 1970, now U.S. Pat. No. 3,660,854 there is shown a spring structure comprising a rigid border wire rectangular in configuration to which are secured spaced pairs of parallel wires fixed at their ends to the frame, said transversely and longitudinally extending pairs of wires being secured to each other at their crossings and providing longitudinally spaced and transversely spaced end supports for coiled springs. In the aforesaid application the wires of a pair of wires in one direction at the seats contain depressions over which the circular end loops of coils are placed and locked to the frame by locking wires which are threaded between the depressed portions and the loops transversely of the wires containing the depressions.

The aforesaid means for attaching the coils to the frame provides for excellent stability and was designed chiefly to enable shipment of the frames and springs to the customer in a less bulky condition than has been heretofore possible and at the same time enable easy assembly without making a large number of individual connections as is usually required where the springs are fastened to the wires by clips which must be applied with tools or which must be secured by spot welding and the like. The fastening means employed in the aforesid application, while a considerable improvement on the prior art, still requires the use of implements and, in fact, is somewhat extravagent in the use of wire. This invention is designed to take advantage of the structure shown in the prior application, to wit, to provide a spring assembly which may be shipped unassembled to the customer and thereafter assembled for use without embodying the need for a locking wire and/or implements to introduce and fasten the locking wire in place.

SUMMARY

As herein illustrated, the spring assembly comprises, in combination, a rectangular frame to which there are attached spaced pairs of transversely and longitudinally extending wires secured at their intersections to each other, said crossing wires providing rectangular coil-supporting seats, each seat comprising spaced parallel portions of said wires and one pair of the spaced parallel portions at each seat containing centrally located depressions, and of coiled springs having circular end loops of greater diameter than the distance between the wire portions containing the depressions, said loops containing reversely bent segments, the distance between which is less than the distance between the wire portions containing the depressions, said coiled springs being seated against the side of the frame from which the depressions extend with the reversely bent segments sprung into the depressions. The depressions are deeper than the thickness of the loops and the segments are sprung into the depressions above the bottom thereof. The distance between the wires of the pairs of wires which do not contain the depressions may be greater or lesser than the diameters of the end loops. If greater the end loops seat only against the wires containing the depressions. If lesser the end loops will seat against the wires at all four sides of the seats. When the latter construction is employed all four wires at each seat may contain depressions and the end loops may be provided with four reversely bent segments for engagement with the depressions in all four of the wires.

The invention will now be described in greater detail with reference to the accompanying drawings wherein:

FIG. 1 is a fragmentary plan view of a spring structure such as may be used for making box springs for beds of furniture, showing pairs of spaced parallel wires, the ends of which are attached to a border wire and coiled springs attached thereto;

FIG. 2 is a plan view, to much larger scale, of the structure shown in FIG. 1, showing the manner in which the coiled springs are attached;

FIG. 3 is an elevation of the upper end of a coiled spring showing the top loop;

FIG. 4 is an elevation of the coiled spring shown in FIG. 3;

FIG. 5 is a fragmentary elevation taken on the line 5--5 of FIG. 2;

FIG. 6 is a vertical section taken on the line 6--6 of FIG. 5;

FIG. 7 is a fragmentary plan view of an alternative structure wherein the end loop of a coiled spring is engaged with all four wires at a seat and is attached to two of the wires; and

FIG. 8 is a fragmentary plan view of an alternative structure wherein the end loop of a coiled spring is engaged with all four wires at a seat and is attached to all four of the wires.

Referring to the drawings (FIG. 1) the spring structure herein illustrated comprises essentially a rigid grid 10 of substantially rectangular configuration and a plurality of coil springs 12 which, as herein illustrated (FIG. 4) are of tapering construction secured to one side of the grid with their axes substantially perpendicular thereto.

The grid 10 is comprised of a rigid border wire 14 having spaced parallel sides 16 and ends 18 to which are secured a plurality of spaced pairs of parallel wires 20 and 22 disposed, respectively, transversely and longitudinally of the frame comprised of the border wire.

The frame 10 and the spaced pairs of longitudinally and transversely extending wires 20 and 22 comprise a grid to which the coils 12 are attached. The coils 12 have end loops 24 and 26, the end loops being of circular configuration, and the end loops 24 each larger than the end loops 26, -- the helix of the coil tapering from the larger loop 24 to the smaller loop 26. other crossing secured.

In accordance with this invention the pairs of wires 20 and 22 are secured at their ends to the border wire by suitable means, for example by welding, by clips or by twisting the end portions of the wire about the border frame and are secured to each other at their intersections by welding so as to provide a dimensionally stable structure wherein the wires are not permitted to move to any substantial degree relative to each other except by limited flexing beteen points of welding. As thus constructed, the crossing pairs of wires provide rectangular coil and seats against which the ends of the coils are adapted to be secured. For the purpose of seating and securing the coils the parallel wires in one direction, at least, are closer to each other than the wires in the other direction, the spacing being determined by the diameter of the larger loops 24 of the coils which are to be seated against the grid. As herein illustrated (FIGS. 1 and 2) the wires 20 are fastened to the border wire so that the distance between them is less than the diameter of the loops 24. The distance betwen the wires 22 is greater than the diameter of the loops.

To secure the coils to the grid at the seats the wires 20 are provided at midlength with depressions 28 (FIGS. 2 and 5) and the loops 24 of the coils are provided with diametrically disposed, reversely bent segments 30 for engagement within these depressions 28. As illustrated, each depression comprises spaced, downwardly extending legs 32--32 and a connecting member 34. The distance between the outer sides of the legs 32--32 is substantially equal to the length of the cord subtending the portion of the loop 24 which underlaps the wires 20 so that when the loop is placed against the seat the depression extends through the loop and has a depth at least as great as the thickness of the wire of the loop and preferably somewhat greater as shown in FIG. 5.

The reversely bent segments 30 of the loop 24 are diametrically disposed with the distance between the inner sides of the bent portions 36 corresponding substantially to the distance between the outer sides of the legs 32 and with the distance between the apices 38 of the segments being less than the distance between the inner sides of the wires 20. These segments lie in the plane of the loop in the form of crimps or ears which extend radially inwardly toward the center of the loop with their inner extremities lying on a circle of smaller diameter than that of the loop. As illustrated, the extremities of the ears extend inwardly beyond the grid wires with which they are engaged and preferably far enough so that the center lines of the grid wires lie between the bottoms of the curves at the bases of the crimps and the bottoms of the curves at the apices of the crimps.

As thus provided the coils are attached to their seats by placing the loops 24 over the depressions, distending the loop 24 diametrically to separate the apices 28 sufficiently to clear the outer sides of the wires 20 and then allowing the loop to contract to its normal configuration so as to move the segments toward each other into the depressions above the bottoms as shown in FIGS. 2 and 5, thus interlocking the loop and the wires. Lateral movement in the direction of the wires 20 is prevented by the reverse bends 36 in the loop which partially encircle the vertically disposed legs 32.

If a strong and resiliently elastic or spring wire is employed for making the coils, attachment of the coils by the means described above becomes extremely simple and provides a very stable and durable structure even under abusive treatment.

In the preferred construction of the spring assembly the wires of the spaced pairs of wires are at a different spacing, and although the coil end seats are rectangular they are not square, that is the distance bteween one pair is less than that of the other pair and as also pointed out the distance between one pair necessarily had to be less than the diameter of the larger loop 24 of the coil. Optionally, as illustrated in FIG. 7, the frame may have spaced pairs of longitudinally and transversely extending wires wherein the wires of the pairs of wires 20' and the wires of the pairs of wires 22' are at the same distance apart and this distance is less than the diameter of the loop 24' so that portions of the loop 24' underlap the wires 20' and 22' at all four sides of the seat. As thus constructed, the wires 20' may be provided with depressions 28' and the loops 24' with reversely bent segments 30' for engagement with the depressions 28'. The portions of the loops 24' overlapping the wires 22' may merely rest against these wires and provide for additional stability. On the other hand, the wires 22', as shown in FIG. 8, may also be provided with depressions 28' and the loop 24' of the coil may be provided with additional reversely bent segments 30' for interengagement with these depressions so as to lock the loops to the wires at all four sides. The latter structure requires, of course, the added operations of making depressions in the wires of both pairs of wires and making four segments and involves an additional operation in assembling in that the segments of each pair must be engaged with depressions in the wires; however, it has the compensating factor that an extremely rugged and durable structure is obtained.

As heretofore pointed out, the structure, as thus made up, is especially designed to enable shipping the frame and coils prior to assembly with a very considerable saving in shipping costs and yet enables assembly for use at its destination by the simple expedient of snapping the coils to their respective seats without need for welding equipment or special tools.

Also the structure as thus made up is much firmer than the conventional spring assembly and enables the customer, that is the mattress manufacturer, to construct the assembly with whatever number of coils are desirable for the particular use proposed and/or as specified by his customers.

It should be understood that the present disclosure is for the purose of illustration only and that this invention includes all modifications and equivalents falling within the scope of the appended claims.

Claims

I claim:

1. A coiled spring for attachment to a grid in the formation of a spring assembly, said coiled spring having at one end an end loop of circular configuration and between the ends intermediate circular windings of substantially smaller diameter than said end loop; characterized in that said end loop has diametrically spaced, aligned, radially, inwardly projecting ears lying in the plane of the loop, said ears being of such length that the distance between the inner extremities thereof is greater than the diameter of the largest of the subjacent intermediate windings.

2. A coiled spring comprising end loops of circular configuration joined by a plurality of intermediate convolutions arranged along an axis perpendicular to the end loops, the loop at one end being tied to the subjacent convolutions and containing diametrically spaced, aligned, radially, inwardly projecting ears extending inwardly therefrom in the plane of the end loop, characterized in that the inner extremities of the ears lie on a diameter which is less than that of the end loop and greater than that of the subjacent intermediate loops.