Swinging seat with improved spring suspension

Abstract

A swinging seat includes suspension members having coil springs of nonlinear response so that the seat has a desirable bouncy feel for a wide range of weights supported on the seat. The springs in one embodiment are barrel shaped having coils of maximum diameter at the middle and coils of minimum diameter at the opposite ends of the spring.

Description

FIELD OF THE INVENTION

[0002] The invention relates to swinging seats such as porch swings or the like and an improved spring suspension system therefore.

BACKGROUND OF THE INVENTION

[0003] Porch swings are a fixture of leisurely living. Many people find the slow, gentle swinging action of a porch swing to be very soothing. As a general rule, porch swings that are commercially available are furnished with a pair of ordinary chains, or “S” hooks, for suspending the swing from the porch ceiling. The chains, or “S” hooks, are inextensible and hence do not provide any bounce or springiness to the suspension of the swing.

[0004] It is also known to include coil tension springs in the suspension of swinging seats to provide such springiness. Representative examples of such seats are shown in U.S. Pat. Nos. 1,390,502, 3,256,016, 4,138,104, 5,564,987, and 5,984,792

[0005] In copending application U.S. patent application Ser. No. 09/569,539, which is commonly assigned, a variable tension spring is described which greatly enhances the comfort of a swinging seat or related device. While this greatly improves the comfort level of a swinging seat further improvements, allowing for comfort over a greater weight range, are still desirable. This is provided by the present invention.

SUMMARY OF THE INVENTION

[0006] The present invention seeks to improve upon the types of swinging seats disclosed in the aforementioned patents. In accordance with the present invention, a porch swing or the like is suspended from a pair of suspension members each of which includes a coil spring having two or more different zones providing two or more different initial spring constants. A first zone of the spring provides a relatively low initial spring constant so that the springs are sufficiently stretched to provide the desired amount of bounce or springiness to the seat when a person of relatively low weight such as a child is sitting on the seat. The second zone provides a relatively high initial spring constant so that when a heavier person, or more than one person, sits on the seat the total elongation of the spring is significantly less than it would be if the entire spring had the spring constant of the first zone. Accordingly, the springs provide a desired amount of stretch and springiness for a much wider range of weights supported on the seat than a conventional spring having a single spring constant. In other words, the springs have a nonlinear spring constant, rather than a linear spring constant as a typical coil spring has.

[0007] Preferably, the springs are barrel shaped having a maximum coil diameter at the middles of the springs and tapering to minimum coil diameters at the two ends of the springs. The largest coils at the middle of the spring provide a relatively low initial spring constant (i.e., the spring constant that applies when the coils are stretched apart starting from an unstretched condition). The smallest coils at the ends of the spring provide a relatively high initial spring constant, and thus will not begin to stretch to any significant extent until the largest coils have already undergone a large degree of stretching.

[0008] In a preferred embodiment the coil spring is provided in a variable leverage suspension device which allows the coil spring to be combined with additional coil springs, or a link, for further extending the weight range over which the seat can comfortably accommodate individuals of varying weights.

[0009] Provided is a swinging seat with resilient suspension. The swing comprises a seat having at least a bottom for supporting one or more persons sitting thereon and a pair of suspension members having lower ends attached to opposite ends of the seat and upper ends adapted to be attached to a ceiling structure for suspending the seat therefrom. The swing has at least one adjustable tension suspension device between the suspension members and the ceiling structure wherein the adjustable tension suspension device comprises a spring tension adjuster, a spanner and at least one coil spring there between.

[0010] Another embodiment is provided in a swinging seat with resilient suspension. The swinging seat comprises a seat having at least a bottom for supporting one or more persons sitting thereon and a pair of suspension members having lower ends attached to opposite ends of the seat and upper ends adapted to be attached to a ceiling structure for suspending the seat therefrom. The swinging seat further comprises at least one adjustable tension suspension device between the suspension members and the ceiling structure wherein the adjustable tension suspension device comprises a spring tension adjuster, a spanner and a coil spring there between. The coil spring has a plurality of coils defining at least first and second zones of differing initial spring constant, the first zone being formed by coils providing a first initial spring constant when said coils are initially stretched, the second zone being formed by coils providing a second initial spring constant substantially greater than the first initial spring constant when said coils are initially stretched, whereby the two zones provide a desired level of resilience for a wide range of weights supported on the seat.

[0011] Yet another embodiment is provided in a method for converting a swing to an adjustable tension suspension swing. The method comprises removing a suspension device between the swing and a fitting and inserting an adjustable tension suspension device between the swing and the fitting. The adjustable tension suspension device comprises a spring tension adjuster, a spanner and a coil spring there between. The coil spring has a plurality of coils defining at least first and second zones of differing initial spring constant, the first zone being formed by coils providing a first initial spring constant when said coils are initially stretched, the second zone being formed by coils providing a second initial spring constant substantially greater than the first initial spring constant when said coils are initially stretched, whereby the two zones provide a desired level of resilience for a wide range of weights supported on the seat.

[0012] A particularly preferred embodiment is provided in a kit for converting a swing to an adjustable tension suspension swing. the kit comprises at least one spring tension adjuster, at least one spanner and at least one coil spring for inserting there between. The coil spring has a plurality of coils defining at least first and second zones of differing initial spring constant, the first zone being formed by coils providing a first initial spring constant when said coils are initially stretched, the second zone being formed by coils providing a second initial spring constant substantially greater than the first initial spring constant when said coils are initially stretched, whereby the two zones provide a desired level of resilience for a wide range of weights supported on the swing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and other objects, features, and advantages of the invention will become more apparent from the following description of certain preferred embodiments thereof, when taken in conjunction with the accompanying drawings.

[0014] FIG. 1 is a perspective view of a porch swing in accordance with an embodiment of the invention.

[0015] FIG. 2 is a sectioned side elevation of a spring in accordance with one embodiment of the invention.

[0016] FIG. 3 is a graph illustrating the nonlinear response characteristic of the spring of FIG. 2.

[0017] FIG. 4 is an embodiment of the present invention wherein the swing is suspended by a device of the present invention.

[0018] FIG. 5 is a detailed view of an inventive suspension system of the present invention.

[0019] FIG. 6 is a detailed view of another inventive suspension system of the present invention.

[0020] FIG. 7 is a prior art swing suspension device wherein the swing is suspended by an inextensible coupler represented as an “S” hook.

[0021] FIGS. 8, 9 and 10 illustrate the inventive swing suspension device in various configurations for various levels of stiffness.

[0022] FIG. 11 illustrates an embodiment of the present invention whereby existing swings can be modified to include the inventive swing suspension device.

DETAILED DESCRIPTION OF THE DRAWINGS

[0023] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

[0024] FIG. 1 shows a porch swing 10 in accordance with an embodiment of the present invention. The swing 10 includes a seat 12 having a bottom 14, a back 16, and two arm rests 18. An uppermost extent in the form of a suspension chain 20 is attached to each of the opposite ends of the seat 12. At some point in each suspension chain 20, preferably at the top end of the chain, a coil spring 22 is disposed. In the illustrated embodiment, the coil springs 22 have their lower ends attached to the top ends of the chains; the upper ends of the springs 22 are attached to suitable fittings 24 fixed to a ceiling or other structure.

[0025] FIG. 2 depicts one embodiment of a spring 22 in accordance with the invention. The spring 22 provides a nonlinear force-displacement characteristic so that the swing will have a desirable bouncy feel for a wide range of weights supported on the seat. To this end, the spring 22 is formed from a wire 40, preferably of constant wire diameter, that is wound about an axis so as to form coils of different diameters in different zones of the spring. A middle zone Z1 of the spring has coils of a maximum diameter Dmax. Opposite end zones Z2 have coils of a minimum diameter Dmin. Advantageously, the coil diameter gradually decreases from the middle zone to the end zones. In a preferred embodiment, the coil diameter decreases by about half the wire diameter from each coil to the next adjacent coil.

[0026] The middle zone Z1 has a relatively low initial spring constant. The end zones Z2 have a relatively high initial spring constant. The coils between the middle zone and the end zones have spring constants intermediate between those of the middle and end zones. The result is a spring having a nonlinear spring rate. FIG. 3 depicts in diagrammatic form the type of nonlinear spring rate provided by the spring.

[0027] In a preferred embodiment of the invention, the spring 22 is formed of 0.218 inch diameter music wire wound to form about 26 coils having a maximum coil diameter of about 1.8 inches at the middle and minimum coil diameters at the two ends of about 1.25 inches, and a length of about 6 inches. The coil diameter decreases by about half the wire diameter from each coil to the next adjacent coil. The following table provides representative force-displacement data for a spring having such a configuration:

         Total
Force    Elongation
(pounds) (in)
25       0.545
50       1.035
75       1.455
100      1.830
125      2.180

[0028] The elongation of 0.545 inches at 25 pounds load is indicative of the spring rate of the largest coils at the middle of the spring. If the entire spring were made up of coils of this diameter, it would be expected that the elongation of the spring at 125 pounds load would be about five times that at 25 pounds load, or about 2.73 inches. It will be noted, however, that the spring elongation at 125 pounds load is actually only about 2.18 inches because of the higher spring constant provided by the smaller coils at the ends of the spring.

[0029] A swing suspended in accordance with an embodiment of the present invention is illustrated in FIG. 4. In FIG. 4, the swing 10, seat 12, bottom 14, back 16, arm rests 18 and suspension chain 20, are as previously described.

[0030] Between the suspension chains 20 and the fittings 24 is an adjustable tension suspension device in accordance with an embodiment of the present invention. The adjustable tension suspension device comprises an upper spring tension adjuster 30 suspended from the fitting 24 at a predetermined location along the length between a first coil spring 22 and a second coil spring 22′. By suspending the upper spring tension adjuster 30 centrally between the two coil springs force is applied to the springs equally and the force required to elongate the springs is higher than with a single coil spring. As the upper spring tension adjuster is suspended towards one coil spring, or the other, the force is disproportionally applied to the closest spring. The closest spring then begins to elongate followed by elongation of the furthest spring. As would be apparent the spring tension adjuster can be suspended in close proximity to a coil spring to approximate a single spring at lower weights.

[0031] The emobodiment illustrated in FIG. 4 can comprise coil springs of equal spring constant on either side of the adjustable tension suspension device or the two coil springs can be of differing spring constants to allow for a wider range of control. In one embodiment the upper spring tension adjuster is preferably closest to the coil spring with the lower spring constant thereby allowing the coil spring with the lower spring constant to elongate initially. The coil spring with the higher spring constant would then elongate with additional force.

[0032] A lower spanner 31 is provided between the lower extent of the two coil springs. The chain 20 is then suspended from the lower spanner. The chain may be suspended from a fixed location, preferably the center, of the lower spanner or the lower spanner may be adjustable to thereby form a lower spring tension adjuster. The same benefit can be obtained by having the upper spring tension adjuster have a fixed suspension location used in combination with a lower spring tension adjuster.

[0033] An alternate embodiment is illustrated in FIG. 5. In FIG. 5, the adjustable spring tension device comprises a single coil spring 22 between an upper spring tension adjuster 30 and a lower spring tension adjustor 31 while the opposite end is maintained at a fixed distance by a link, 32. It would be apparent that the closer the suspension locations are to the spring the lower the downward force required to elongate the spring a given amount. Suspension locators, 33, are provided along the upper and lower spring tension adjusters to insure that the suspension location remains fixed in use. A notch is a particular preferred suspension locator due to the simplicity in manufacturing and use. Protrusions, preferably separated to avoid sliding along the spring tension adjuster, are equally suitable for demonstration of the present invention.

[0034] An alternative embodiment is illustrated in FIG. 6. In FIG. 6, the upper spring tension adjuster 30 and lower spacer 31 are connected by two coil springs 22 as described and illustrated previously. Optional arrest links 34 are provided parallel to each spring. The arrest link prohibits the spring from elongating beyond the length of the arrest link. The arrest link is particularly preferred in an embodiment comprising two coil springs of differing spring constant. The coil spring with the lower spring constant can extend first up till the point where further extension is prohibited by the length of the arrest link. The coil spring with the higher spring constant can extend concurrent with the extension of the lower spring constant coil spring or it can initiate elongation concurrent with the coil spring of lower spring constant reaching the maximum elongation allowed by the arrest link. In one embodiment the arrest length is interior to the coil spring for aesthetic purposes.

[0035] A particularly common swing suspension device of the prior art is illustrated in FIG. 7. In FIG. 7, the upper extent 35 of a swing comprises a hook 36 which is connected to a fitting 24 by an “S” hook 37. The hook typically threadably engages with a pin inserted through the upper extent perpendicular to the hook. By replacing the pin with a similarly threaded spanner the “S” hook can be replaced with a spring suspension device of the present invention.

[0036] An embodiment of the present invention is illustrated in FIGS. 8-10 wherein the various configurations are shown. In FIG. 8, the upper spring tension adjuster, 30, is suspended from a fitting, 24, in a centrally located suspension locator 33 thereby encouraging downward force on the swing to be applied to both spring coils equally. This configuration would provide the most resistance to elongation of the coil springs and therefore provide the most firm feel and be suitable for heavier individuals. A spanner 31 receives the lower end of the coil spring 22. The hook 36 is preferably threadably engaged with the spanner 31 interior to the upper extent 35. In FIG. 9, the upper spring tension adjuster 30 is suspended in an intermediate located suspension locator 33. As downward force is applied to the swing the coil spring closest to the fitting, or the rightward spring in the illustration, would begin to elongate prior to the further, or leftmost, coil spring elongation. This would provide a softer feel than the configuration of FIG. 8. In FIG. 10, the locator closest to the end of the upper spring tension adjuster 30 is utilized thereby further relying on one coil spring initially with more downward force required to initiate elongation of the second coil spring. The configuration in FIG. 10 would provide a softer feel than the configuration illustrated in FIG. 9.

[0037] A kit for converting an existing swing to a swing comprising the adjustable spring tension device of the present invention is illustrated and will be described with reference to FIG. 11. In FIG. 11 the kit comprises a multiplicity of coil springs 22 and a multiplicity of spring tension adjusters 30. The kit could be implemented by replacing an “S” hook 37 with two spring tension adjusters and coil springs 22 there between. In another embodiment the hook 36 and optional washer 42 can be removed from the pin 41. The pin 41 can then be replaced by the spanner 31 and springs provided between the spanner and spring tension adjuster 30 as would be apparent from the teachings herein. Optional but preferred spring end caps 43 can be provided for covering the end of the spring wire.

[0038] The invention thus provides a unique swinging seat having a desirable bouncy feel for a wide range of weights so that persons of widely differing sizes and ages from children to adults can enjoy the soothing support that the seat provides.

[0039] Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings.

[0040] Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A swinging seat with resilient suspension, comprising: a seat having at least a bottom for supporting one or more persons sitting thereon; and a pair of suspension members having lower ends attached to opposite ends of the seat and upper ends adapted to be attached to a ceiling structure for suspending the seat therefrom; at least one adjustable tension suspension device between said suspension members and said ceiling structure wherein said adjustable tension suspension device comprises a spring tension adjuster, a spanner and at least one coil spring there between.

2. The swinging seat of claim 1 wherein said coil spring has a plurality of coils defining at least first and second zones of differing initial spring constant, the first zone being formed by coils providing a first initial spring constant when said coils are initially stretched, the second zone being formed by coils providing a second initial spring constant substantially greater than the first initial spring constant when said coils are initially stretched, whereby the two zones provide a desired level of resilience for a wide range of weights supported on the seat.

3. The seat of claim 2, wherein the coils in said first and second zones are wound helically about an axis of the spring and the coils in said first zone are wound at a diameter from the axis that is substantially greater than that at which the coils in said second zone are wound.

4. The seat of claim 1 wherein said spring tension adjuster comprises suspension locators for position said coil spring along said spring tension adjuster.

5. The seat of claim 4 wherein said suspension locators are notches.

6. The seat of claim 1 comprising two said coil springs between said spring tension adjuster and said spanner.

7. The seat of claim 6 wherein said two coil springs each have a different spring constant.

8. A swinging seat with resilient suspension, comprising: a seat having at least a bottom for supporting one or more persons sitting thereon; and a pair of suspension members having lower ends attached to opposite ends of the seat and upper ends adapted to be attached to a ceiling structure for suspending the seat therefrom; at least one adjustable tension suspension device between said suspension members and said ceiling structure wherein said adjustable tension suspension device comprises a spring tension adjuster, a spanner and a coil spring there between; and wherein said coil spring has a plurality of coils defining at least first and second zones of differing initial spring constant, the first zone being formed by coils providing a first initial spring constant when said coils are initially stretched, the second zone being formed by coils providing a second initial spring constant substantially greater than the first initial spring constant when said coils are initially stretched, whereby the two zones provide a desired level of resilience for a wide range of weights supported on the seat.

9. A swing comprising an adjustable tension suspension device comprising: a spring tension adjuster, a spanner and a coil spring there between; and wherein said coil spring has a plurality of coils defining at least first and second zones of differing initial spring constant, the first zone being formed by coils providing a first initial spring constant when said coils are initially stretched, the second zone being formed by coils providing a second initial spring constant substantially greater than the first initial spring constant when said coils are initially stretched.

10. The swing of claim 9 wherein said coil spring is positioned along said spring tension adjuster.

11. The swing of claim 9 comprising a second coil spring.

12. The swing of claim 9 comprising a link between said spring tension adjuster and said spanner.

13. The swing of claim 12 wherein said link is an arrest link.

14. The swing of claim 9 wherein said spanner is a spring tension adjuster.

15. A method for converting a swing to an adjustable tension suspension swing comprising: removing a suspension device between said swing and a fitting; inserting an adjustable tension suspension device between said swing and said fitting wherein said adjustable tension suspension device comprises: a spring tension adjuster, a spanner and a coil spring there between; and wherein said coil spring has a plurality of coils defining at least first and second zones of differing initial spring constant, the first zone being formed by coils providing a first initial spring constant when said coils are initially stretched, the second zone being formed by coils providing a second initial spring constant substantially greater than the first initial spring constant when said coils are initially stretched, whereby the two zones provide a desired level of resilience for a wide range of weights supported on the seat.

16. The method for converting a swing to an adjustable tension suspension swing of claim 15 further comprising: attaching a second coil spring between said spring tension adjuster and said spanner.

17. The method for converting a swing to an adjustable tension suspension swing of claim 15 further comprising: attaching a link between said spring tension adjuster and said spanner.

18. A kit for converting a swing to an adjustable tension suspension swing comprising: at least one spring tension adjuster, at least one spanner and at least one coil spring for inserting there between; and wherein said coil spring has a plurality of coils defining at least first and second zones of differing initial spring constant, the first zone being formed by coils providing a first initial spring constant when said coils are initially stretched, the second zone being formed by coils providing a second initial spring constant substantially greater than the first initial spring constant when said coils are initially stretched, whereby the two zones provide a desired level of resilience for a wide range of weights supported on the swing.

19. The kit of claim 18 further comprising a link.

20. The kit of claim 19 wherein said link is an arrest link.

21. The kit of claim 18 wherein said coil spring is positionable along said spring tension adjuster.