US3767180A

US3767180A - Coil spring lock

Info

Publication number: US3767180A
Application number: US00153969A
Authority: US
Inventors: M Kaiser
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-06-17
Filing date: 1971-06-17
Publication date: 1973-10-23
Anticipated expiration: 1990-10-23
Also published as: CA956042A

Abstract

An upholstery spring is disclosed, consisting of a length of wire helically coiled with the end convolutions closed to define two circles. The wire ends are wrapped about the adjacent turn at points where an obtuse elbow is located. The wire end crosses inwardly against the elbow and then wraps around the wire immediately adjacent the bend, to trap one leg of the elbow between the wrapped end and the portion crossing inwardly against the elbow, thereby preventing the wire end from slipping on the adjacent turn.

Description

United States Patent 1 Kaiser Oct. 23, 1973 COIL SPRING LOCK [76] Inventor: Martin Kaiser, 66 Spencer Ave.,

Toronto 3, Ontario, Canada [22] Filed: June 17, 1971 [21] Appl. No.: 153,969

[52] US. Cl. 267/91, 267/179 [51] Int. Cl Fl6t 3/04 [58] Field of Search 267/142, 91, 179, 267/1; 5/260, 256

[56] References Cited UNITED STATES PATENTS 2,161,165 6/1939 Hirschman 267/142 2,641,758 6/1953 Levine 267/142 2,249,999 7/1941 Asaro..... 5/260 3,190,631 6/1965 Kaiser 267/179 FOREIGN PATENTS OR APPLICATIONS 1,191,747 10/1959 France 267/147 Primary Examiner-James B. Marbert At!orneySim et al.

[57] ABSTRACT An upholstery spring is disclosed, consisting of a length of wire helically coiled with the end convolutions closed to define two circles. The wire ends are wrapped about the adjacent turn at points where an obtuse elbow is located. The wire end crosses inwardly against the elbow and then wraps around the wire immediately adjacent the bend, totrap one leg of the elbow between the wrapped end and the portion crossing inwardly against the elbow, thereby preventing the wire end from slipping on the adjacent turn.

6 Claims, 3 Drawing Figures Patented Oct. 23, 1973 mmgnm INVENTOR. MARTIN KAISER gaw M gwuw Aqent con. SPRING LOCK This invention relates generally to spring-filled furniture such as mattresses, box springs, chesterfields, chairs and the like, and has to do particularly with an improved form of the conventional upright helical springs which are utilized in the construction of these items.

The conventional upright helical spring utilized in the manufacture of mattresses, chesterfields, etc. is made from a single piece of wire which is configured to define a helix of about four or five convolutions, the end convolutions being of larger diameter than the intermediate convolutions. Usually, the end convolutions are closed to form closed end coils, and the closure takes place by wrapping the wire end tightly about the wire where it begins to define the adjacent convolution. Generally speaking, the upper and lower coils are substantially circular and lie in parallel spaced-apart planes at right-angles to the spring axis.

One of the most difficult aspects of manufacturing these upright helical springs is related to the tendency of the end coils to increase in diameter upon compression of the spring and to decrease indiameter upon subsequent expansion of the spring. This tends to urge the wrapped ends of the spring wire to move along the adjacent convolution, a movement which is made easier by the fact that when the internalconvolutions of the spring are flattened the wire tends to twist within the wrapped ends.

Some attempts have been made in the prior art to overcome this difficulty by attempting to limit. the movement of the wrapped end upon the adjacent convolution, usually by joggling or bending the main wire at the point where the end is wrapped upon it.

Exemplary of the prior art in this respect is my own U.S. Pat. No. 3,190,631, issued June 22, 1,965, and entitled Coil Spring Lock. While the spring configuration disclosed in my earlier U.S. Pat. No. 3,190,631 represents an improvement over the previous techniques, I have nonetheless found some difficulty in achieving an absolutely tight andimmovable grip of the wire end on the adjacent convolution, the reason for this being that the construction in my U.S. Pat. No. 3,190,631 has the wrapped wire end coiled about a portion of wire having a bend at either end. The difficulty arises in attempting to position these two bends at exactly the right spacing so that the wrapped wire end cannot budge.

I have now discovered a construction which achieves an immovable grip of the coiled wire end on the adja cent convolution, and which at the same time obviates the necessity for one of the bends at the location on the adjacent convolution where the wire end is to be wrapped.

Essentially, the improvement I have now discovered is to provide only one bend in the adjacent ocnvolution, to bend the portion adjacent the free end of the wire obliquely inwardly within the plane of the end coil to abut the bend cross-wise, and then to coil the end of the wire about the end coil immediately adjacent the bend, in such a way that the wire end forms a helix of the opposite sense from the helix of the spring. In other words, if the spring helix is clockwise, the wire end wrapping helix is counter-clockwise.

More specifically, this invention provides an upholstery spring comprising a single length of wire having two ends and configured to define a substantially helical spring, the. helical spring including a plurality of convolutions, of which an end convolution is closed to define an end coil of substantially circular shape lying substantially in a single plane, the end coil being closed by having the respective end of the wire wrapped about the wire where the end coil merges with the adjacent convolution, the portion of the wire which links the end coil with the adjacent convolution being bent obliquely away from the plane of the end coil to define an obtuse angle at the point of merging, the portion of the wire immediately adjacent said respective end of the wire being bent inwardly in said plane so as to abut said ohtuse angle, the end of the wire being wrapped tightly in a helix of the opposite sense from the helix of the spring at least two full turns around the wire in the end coil immediately adjacent said obtuse angle.

One embodiment of this invention is shown in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which:

FIG. 1 is a perspective view of a completed upright helical spring incorporating the improvement of this invention;

FIG. 2 is a plan view of the lower end coil and a portion of the adjacent convolution of the spring of FIG. 1; and

FIG. 3 is an elevational view of the lower end coil shown in FIG. 2.

Attention is first directed to FIG. 1, which shows an upholstery spring 10 which is made from a single length of wire 11 configured to define substantially a helix of which the middle convslutions 12 are of smaller diameter than the end convolutions l4 and 16. The wire 11 has two

ends

17 and 18. The end 17 is brought against and wrapped around the wire 1 1 to define an upper end coil 20, while the end 18 is brouhgt against and wrapped around the wire 11 to define a lower end coil 22. The end coils 20 and 22 are substantially circular and lie substantially in spaced-apart parallel planes.

As can be seen in the Figures, the portion of the wire 11 which links the lower end coil 22 with the adjacent convolution 23 is bent obliquely upwardly from the plane in which the lower end coil 22 is located, and defines an obtuse angle in a vertical plane at the point where the end coil 22 merges with the adjacent convolution 23. The obtuse angle is indicated by the number 25 in FIG. 3 and the location of the bend is labelled with the number 27. The bend at 27 is not a precise sharp bend, as this would weaken the spring material. The bend at 27 is in fact a curve with a very small radius, but is sharp enough to be spoken of as a bend. The portion of the wire immediately adjacent the end 18, generally indicated by the numeral 30 is bent inwardly in the plane of the lower end coil 22 so as to abut the obtuse angle elbow at the point 27 in a cross-wise fashion. This is clear from FIGS. 2 and 3, which show the portion 30 bending toward the centre of the circular bottom coil 22 and cutting directly across and against the elbow at the point 27. Then, the end of the wire passes inwardly, upwardly and tightly around the part of the wire in the lower end coil 22 which is immediately adjacent the elbow at 27. It will be noted that the end 18 is wrapped at least two full turns, and that these turns are tightly wrapped against each other. Furthermore, the direction of wrapping the end 18 in a helix has the opposite sense from the helix of the spring 10. This latter feature isessential to this invention. It will be noted in the embodiment shown that the helical spring of FIG. 1 is a clockwise helix, while the wrapping of the end 18 is a counter-clockwise helix.

Naturally, if the helical spring 10 were a counterclockwise helix, the wrapping of the end 18 would be a clockwise helix.

The identical attachment configuration takes place at the upper end coil 20, but because this is identical it has not been shown in separate Figures. It will be noted, however, that the helical wrap of the end 17 is also counter-clockwise, the same as that of the end 18.

Because the

ends

17 and 18 are wrapped tightly up against the elbows, such as the elbow 27 in the lower end coil 22, and because the wire immediately adjacent the end is bent inwardly to cut across the elbow, the join between the

ends

17 and 18 and the wire 11 is impossible to move with respect to the wire 11. Looking at FIGS. 2 and 3, the portion 30 of the wire prevents the point of attachment from sliding leftwardly (as viewed in FIG. 3) along the wire 11, while the wrapped coils of the end 18, hard up against the elbow at 27, prevent the point of attachment from sliding to the right.

It is thus seen that the construction herein disclosed requires only a single bend at the point of attachment, but yields a very secure joint.

In order to compensate for the inward bend at 30 in FIGS. 2 and 3, the portion 32 of the lower end coil 22 (immediately adjacent the elbow at 27) should be bent slightly inwardly and straightened to some extent. It will be noted in FIG. 2 that this inward bending does not cause the coil 22 to depart seriously from circularity.

What I claim as my invention is:

1. An upholstery spring comprising a single length of wire having two ends and configured to define a substantially helical spring, the helical spring including a plurality of convolutions, of which an end convolution is closed to define an end coil of substantially circular shape lying substantially in a single plane, the end coil being closed by having the respective end of the wire wrapped about the wire where the end coil merges with the adjacent convolution, the portion of the wire which links the end coil with the adjacent convolution being bent obliquely away from the plane of the end coil to define an obtuse angle at the point of merging, one arm of the obtuse angle lying in said plane, the portion of the wire immediately adjacent said respective end of the wire being bent inwardly in said plane so as to abut said obtuse angle, the end of the wire being wrapped tightly in a helix of the opposite sense from the helix of the spring at least two full turns around the wire in the end coil immediately adjacent said obtuse angle.

2. An upholstery spring as claimed in claim 1, in which both end convolutions are closed to define end coils, the end coils lying in spaced parallel planes.

3. An upholstery spring as claimed in claim 2, in which the convolutions intermediate the end coils are of smaller diameter than the end coils.

4. An upholstery spring as claimed in claim 1, in which the helix of the spring is a clockwise helix while the helix of the wrapped wire end is a counterclockwise helix.

5. An upholstery spring as claimed in claim 1, in which the portion of the end coil immediately adjacent the obtuse angle is bent slightly inwardly away from circularity and is substantially straight.

6. An upholstery spring as claimed in claim 3, in which the helix of the spring is a clockwise helix, and in which the portion of the end coil immediately adjacent the obtuse angle is bent slightly inwardly away from circularity and is substantially straight.

Claims

4. An upholstery spring as claimed in claim 1, in which the helix of the spring is a clockwise helix while the helix of the wrapped wire end is a counter-clockwise helix.