CA1140960A

CA1140960A - Cushioning device

Info

Publication number: CA1140960A
Application number: CA000376255A
Authority: CA
Inventors: Kenneth Richardson
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-04-27
Filing date: 1981-04-27
Publication date: 1983-02-08
Also published as: JPS57192575A; EP0064359A3; EP0064359A2; AU8300582A

Abstract

ROGERS, BERESKIN & PARR C A N A D A

Title: CUSHIONING DEVICE
Inventor: KENNETH RICHARDSON

ABSTRACT OF THE DISCLOSURE

The disclosure relates to a cushioning device.
According to a preferred embodiment of the invention, the device takes the form of a trampoline and includes a hollow inflatable annulus extending about an axis and defining respective end planes generally normal to said axis, whereby the annulus can be supported on a horizon-tal surface in one of said planes with its said axis generally upright. The annulus is enclosed by a net which provides an exercise surface extending across at least part of the central opening of the annulus in the other of the said planes. The device also includes means for limiting inward expansion of the annulus.
The annulus is capable of resiliently cushioning im-pacts resulting from a person jumping on said surface, and of causing the surface to rebound subsequent to each impact.

Description

This invention relates to a cushioning device intended primarily (but not exclusi~ely) for use as a trampoline.
Traditionally, a trampoline comprises a relatively large rectangular sheet of canvas or the like supported by springs from a rigid rectangular frame having support legs at its corners. The canvas sheet provides a relatively large exercise area, allowing the trampoline to be used for gymnastic exercises.
The beneficial effects of trampoline exercising have long been - -recognized, but generally a high degree of skill and physical fitness is required for a person to be able to effectively use a trampoline. It has also been recognized that relatively simple bouncing exercises on a trampoline can nevertheless form an effective part of body toning programmes.
Small circular trampolines have been proposed for use by individuals following a body toning programme. These trampolines have a rigid circular frame of relatively small diameter (four or five feet) from which a circular sheet of canvas or the like is suspended by springs. Despite their relatively small size, these trampolines are still quite cumber-some and are not readily portable.
An object of the present invention is to provide animproved cushioning device which, according to one embodiment of the invention, takes the form of a trampoline designed primarily for use by an individual in performing bouncing or jumping exercises.
The trampoline provided in accordance with this preferred embodiment includes a hollow inflatable annulus extending about an axis and defining respective end planes ,, ~

generally normal to said axis, whereby the annulus can be supported on a horizontal surface in one of said planes with its said axis generally upright. ~eans supported by said annulus and providing an exercise surface extends across at least part of the central opening of the annulus at a spacing from said one plane. The annulus is capable of resiliently cushioning impacts resulting from a person jumping on said surface, and of causing said surface to rebound subsequent to each impact.
According to an alternative embodiment of the invention, the device may be used as a seating unit.
More broadly, the invention provides a cushioning device which includes a hollow inflatable annulus of the form defined above.
lS A primary advantage of a cushioning device of the form provided by the invention is that it can be made readily collapsible by deflating the annulus for ease of transportation and storage. Also, the degree of cushioning provided can be controlled by inflating the annulus to an appropriate extent.
In order that the invention may be more cleariy understood, reference will now be made to the accompanying drawings which illustrate a number of preferred embodiments of the invention by way of example, and in which:
Fig. 1 is a perspective view, partly broken away, of a cushioning device intended for use as a trampoline according to a preferred embodiment of the invention;

- 114~)~60 Fig. 2 is a plan view corresponding to ~ig. 1;
Fig. 3 is a sectional view on line III-III of Fig. 2;
Fig. 4 is a plan view corresponding to Fig. 2 but with the mat of the trampoline removed;
Fig. 5 is a sectional view on line V-V of-Fig. 4;
and, Figs. 6 to 15 illustrate alternative embodi-ments of the invention and will be more particularly described later.
Reference will first be made to Figs. 1 to 5 in describing a trampoline provided in accordance with a preferred embodiment of the invention. The trampoline includes a hollow inflatable annulus denoted 20 which supports two mats 22 and 24 providing respective exercise surfaces of the trampoline. In Figs. 4 and 5, the mats have been omltted in order to show details of an outer nylon net indicated at 26 ~by which the mats are supported), and an inner net 28 of annular form which closely surrounds the annulus and provides means for limiting radial expansion of the cross-section of annulus 20 (see later).
Referring primarily to Figs. 2 and 3, it will be seen that annulus 2G extends about an axis 30 and defines a respectlve end planes 32 and 34 generally normal to the axis.
The annulus can be supported on a surface coincident with either one of the planes 32 or 34 and with axis 30 generally upright. In other words, the annulus is reversible and can lie on either side with its opening facing upwardly. Two mats are provided so that the trampoline can be used either way up. The two mats may have different surface charac-teristics. For example, mat 22 could be a plain mat while mat 24 might have an outer (exercise) surface covered with an array of small protuberances designed to exert a "massaging"
effect on the feet of person using the trampoline. However, in this particular embodiment, the two mats are the same and are both formed from interwoven polypropylene fibres. The mats are both secured to the supporting outer net 26 by adhesive, although other fastening methods may be used (see later).
A mat made of woven polypropylene fibres has been found to be particularly suitable in this embodiment of the invention because it is pervious to air. Thus, the particu-lar trampoline shown is designed to use a relatively largediameter mat (as compared with the diameter of annulus 20) and to permit air to pass through the mat as it moves up and down in use. If the mat were not pervious to air, a "piston" effect would occur and the air trapped below the mat would severely inhibit up and down movement of the mat. Of course, in an alternative embodiment, the trampo-line could be designed to use an air-impervious mat, for example, by making the mat smaller or by providing a support for the annulus which would allow air to escape outwardly around the bottom of the annulus.
The annulus itself is capable of resiliently cushioning impacts resulting from a person jumping on either of the mats 22 and 24 and of causing the relevant mats to rebound subsequent to each impact. In this embodi-ment, the annulus is made of butyl rubber and has an outside diameter of 44 inches and an inside diameter of 24 inches. The annulus is of circular cross-section of 10 inches diameter. In Fig. 2 a valve for inflating the annulus is indicated at 36. In another embodiment, the valve could be designed to be stowed within the annulus or otherwise disguised, for example, in a carrying handle at the external diameter of the annulus. It is preferable for the annulus to be inflatable and deflatable so that the trampo-line can be collapsed for ease of transportation and storage, although within the broad scope of the invention, the annulus could of course be permanently inflated.
Referring now primarily to Figs. 4 and 5, the two nets 26 and 28 are made of nylon filaments fused together ln a crlss-cross configuration defining squares with 1 inch sides. Parts only of the two nets are shown in Fig. 4 for ease of illustration but in fact both nets are complete as shown in Fig. 1. Net 26 completely encloses the annulus and is fitted relatively tightly therearound. It is formed from an appropriate length of net which is seamed into a tube with and one end of which is closed by tying the net.
The net is then draped over the annulus and the other end of the tube is tied to a retaining ring indicated at 38 in Fig. 4. The annulus can then be inflated until the required tension is obtained in net 26. Finally, the two mats 22 and 24 are secured to the respective sides of the outer net.

~14V960 The inner net 28 is of annular form and is shaped to closely fit around and enclose the annulus itself.
The net is formed around the annulus into a tube by wrapping a generally annular shaped net section around the annulus and securing together the inner and outer circular edges of the annular net around the inner diameter of annulus 20.
This can be done by securing the edges together using suita-ble adhesive or by providing buttons or other projections on one edge which are engaged through the net along the opposite edge. In any event, the inner net 28 fits snugly around the annulus and has the effect of limiting radial expansion of the cross-section of the annulus; that is, the dimension indicated by arrow D in Fig. 5.
In practice, it has been found preferable to provide some means such as net 28 for restricting inward radlal expansion of the annulus ~that is, expansion which would have the effect of reducing the internal diameter of the annulus) whlle the annulus is being inflated. Such expansion would have the effect of closing the central opening of the annulus and thereby reducing the area which will be available for bouncing. Thus, when the annulus expands during inflation, it will eventually begin to tension the outer net and in fact the intention is that the annulus will be inflated until the outer net is tensioned to the extent appropriate for the required characteristics of the trampoline. Typically, the internal pressure of the annulus might be in the range 4 pounds to 9 pounds per square inch but this will depend on the resiliency of the material from which the annulus is made and on the personal .

1~4~60 _ -- 8 preference of the user. In any event, as the annulus begins to tension the outer net, the resistance provided by that net will have the effect of tending to cause the annulus to expand inwardly as inflation continues~
It may be possible to limit inward expansion of the annulus by using a specially designed annulus, for example, one which has walls which are thicker around the ~nternal circumference of the annulus than around the outer circumference. However, this form of annulus may be expen-sive to manufacture and, for this reason, it may be preferred to use an annulus having uniform wall thickness. Inward radial expansion could then be controlled by a rigid inner "hub" inside the annulus (see Figs. 9 and 10) but this has the disadvantage that the annulus is not then completely collapsible. Another possibility would be to provide rigid rings extending around the end circumference of the annulus, but again the problem of non-collapsibility remains.
It has been found preferable to control inward radial expansion of the annulus by limiting radial expansion of the annulus cross-section (dimension D in Fig. 5) such as the inner net 28. In this way, it has also been found possible to exercise some control over the "bounce" provided by the trampoline and prevent it from becoming too soft.
Thus, it may not be possible to control the resiliency and "bounce" of the trampoline entirely by varying the inflation pressure of annulus 20. If the pressure is increased to reduce the resiliency, the trampoline becomes 'Ihard'' and 1~4(~960 g "lifeless". Conversely, if the pressure is reduced too far the annulus becomes too soft and the trampoline may tend to "throw" a person who jumps anywhere but directly in the centre of the trampoline; in other words, the trampoline becomes unstable.
Net 28 has been found to provide a particularly expedient means for limiting inward expansion of annulus 20 but other means may alternatively be used; examples of such other means will now be described with reference to Figs. 6 to 10.
Figs. 6, 7 and 9 are plan views showing three alternative means which may be employed to prevent inward radial expansion of the annulus of a cushioning device of the form provided by the invention. Figs. 8 and 10 are cross-sectional views taken respectively on lines VIII-VIII
of Figs. 7 and on line X-X of Fig. 9.
In each of Figs. 6 to 10, the annulus itself is generally denoted by reference numeral 20. In the embodiment of Fig. 6, the annulus is wrapped by straps 40 of a material capable of stretching in one direction only (for example~a knitted material having inextensible filaments extending in one direction). The material is arranged so that the straps 40 are inextensible in the direction extend-ing circumferentially around the cross-section of the annulus but can stretch in the circumferential direction of the annulus. In this way, the annulus can grow radially outwardly while the cross-section of the annulus remains substantially constant. The straps 40 may be formed from 114~960 a continuous len~th of material spirally wound around the annulus or individual straps may be used.
It will of course be understood that an outer net or other expedient will be used externally of the straps 40 but has been omitted for clarity of illustration.
Referring now to Figs. 7 and 8, in this embodiment expansion of the cross-section of the annulus is controlled by a "glove" generally denoted by reference numeral 42. This glove is made of a material which is substantially inextensible and is shaped to enclose annulus 20. The glove is formed with a series of slits or openings, some of which are indi-cated at 44, which allows the glove to have an external circumferential dimension greater than its internal circum-ferential dimension sufficient to fit snugly around annulus 20. For ease of illustration, only some of the slits 44 have been shown in Fig. 7 but it will of course be understood that the slits will extend right around the glove. A zip fastener 46 extends around the inner circumference of glove 42 and provides a means by which the glove may be fitted to and removed from the annulus. In other embodiments, zip fastener 46 could of course be replaced by snaps or other fasteners.
Figs. 7 and 8 also illustrate an alternative method by which the nets providing exercise surfaces may be supported from annulus 20. While this featuxe has been specifically illustrated in conjunction with the glove 42, it is to be understood that it may be used with other forms of inner expansion control means. In this embodiment, only one net is shown and is indicated by reference numeral ~14~ 60 48. The mat is su~pcrted by a plurality of straps 50 each of which has an inner end sewn to mat 48 and which extends radially outwardly of mat 48 and around annulus 20. At the underside of the annulus as seen in Fig. 7, the straps may be sewn to a second similar mat or to some other form of anchoring means. Alternatively, the straps could extend right around below the annulus and be attached ~o mat 48 at the opposite ends. In the particular embodiment illustrated in Fig. 7, it is to be noted that the straps 50 are specifi-cally positioned over the slits 48 in the glove 42 so thatannulus 20 can to some extent expand through the slits and act directly on the straps 50 for tensioning mat 48.
Figs. 9 and 10 illustrate a further alter~
native embodiment in which inward radial expansion of annulus 20 is prevented by a rigid inner hub 52 around which the annulus extends. It will be noted from Fig.
10 that the hub 52 is of arcuate shape in cross-section so as to conform generally to the curvature of annulus 20. The annulus is merely placed around the hub and inflated and i6 not secured to the hub.
The particular form of the trampoline provided by the invention has many advantages compared with prior art trampolines including collapsibility and ready porta-bility. The characteristics of the trampoline can be readily varied at will by varying inflation of the annulus.
In addition, it has been found in practice that the tramp-oline provides a "ride" which is particularly pleasing.
Not only does the inflated annulus provide cushioning but ., 114~960 the particular design of the tr~mpoline provides for added resiliency which has been found to gi~e the user a "floating"
feeling and be particularly useful in body toning e~ercises.
Referring particularly to Fig. 3, it will be appreciated 5 that an impact downwardly in the direction of arrow A on to mat 22 will have the effect not only of partially com-pressing the annulus, but the tension forces engendered in the upper surface of the outer net 26 at the time of impact, will cause the annulus 20 to tend to "roll" inwardly as lO indicated by arrow B. In other words, the annulus will not only be compressed axially, but will also be torsionally stressed or "rolled" inwardly which will have an additional effect on the "bounce" of the trampoline. When the user reaches the bottom of the bounce both the air pressure within 15 the annulus and the resilient nature of the walls of the annulus will cause the components of the trampoline to tend to restore towards their original conditions providing for a rebound effect on the user.
Reference will now be made to Figs. 11 to 15 in 20 describing further features of the invention. Fig. 11 is a perspective view of a stand which may be used in conjunc-tion with a cushioning device of the form provided by the invention; in Figs. 12 and 13, the device and stand are shown in use together forming a seating unit, while in 25 Figs. 14 and 15 the stand is used as a support during use of the cushioning device as a trampoline. In each of Figs.
12 to 15, the cushioning device is generally indicated by reference numeral 54 and the stand is denoted as 56.

Referring first to Fig. 11, the stand has a three-legged form generally similar to an easel and comprises a front frame 58 which is generally of inverted U-shape and which defines the two front legs of the stand. A third, telescopic leg extends downwardly from the top of frame 58 and is denoted 60. Hand grips 62 are provided on either side of the point of attachment of leg 60 to frame 58.
These hand grips may be omitted where the stand is used solely as part of a seating unit. A nylon cord 64 is secured between the legs of the stand for controlling their spread.
Two short arms 66 and 68 protrude forwardly from the respect-ive legs of frame 58 and a sling 70 extends between the arms and forms a support for the cushioning device 54 as best shown in Figs. 12 and 13. In the embodiment of Figs.
14 and l5, these arms 66 and 68 and slings 70 are omitted.
Referring to Figs. 12 and 13, it will be seen that the cushioning device 54 is supported on sllng 70 against the legs of frame 58. The cushioning devlce itself is essentially of similar form to the device as shown in Figs. 1 to 5 in that it comprises an annulus 20, an outer net 26, and an inner net 28. The device has an inner mat 22 only and the device is placed so that the mat 22 is disposed at the side of the device which is in contact wlth stand 56. The portion of the outer net 26 at the opposite side of the device is relaxed and hangs loosely inside the space at the centre of annulus 20 and is indicated by reference numeral 26a in Fig. 13. This relaxed portion ~.

1~4~:)960 of the net provides a "pocket" in which a person can sit, whereby the cushioning device and stand form a seating unit.
Relaxation of the outer portion 26a of net 26 is possible because a tension control band indicated at 72 is incorporated in the outer net. This band takes the form of a wire or cord woven into the outer net and tightened about annulus 20 so that the portion of net 26 which carries mat 22 cannot pull around the annulus while the outer portion 26a can be relaxed. Tension in this outer portion of the net is released by detaching the net from the retaining ring 38 (Fig. 4). In this embodiment, the ring will take the form of a length of cord or rope which can be simply released to relax the outer portion of the net.
Figs. 14 and 15 are side and plan views respect-ively showing the stand 56 (without the arms 66 and 68 or 81ing 70) ln association with a trampoline 54 of the form provided by the invention. The trampoline is placed between the two front legs of the stand and the person using the trampoline can grasp the stand at the position of the hand grips 62 and use the stand as a support. It is thought that this facility of using the stand as a support will be particularly useful for people learning to use the trampoline or for people havlng a physical disability. For example, the stand/trampoline combination could be used as a rehabi-litation apparatus for people recovering from injuries.
It will of course be appreciated that the preceding description relates to specific embodiments of the invention and that many modifications are possible within the ~road scope of the invention (in addition to or instead of the modifications referred to above). For example, the particular materials and dimensions referred to are given merely by way of example and may vary in practice. The annulus may be made of any appropriate material having a resilient memory.
In the embodiments described with reference to the drawings, the cushioning device is referred to as having two mats (22 and 24) and reference is also made to the possibility of using a single mat only. In another embodiment, the mats could be omitted entirely (for example, where the cushioning device is to be used as part of a seating unit). Where the mats are omitted and the device is to be used as a trampo-line, the outer net or equivalent may itsélf provide the exercise surface(si of the trampoline. Where one or more mats are provided, they need not be necessarily secured to the outer net by adhesive as described above. Each mat could ln fact be made as two layers positioned on respect of the opposite sides of the outer net and stitched together through the net. Another possibility would be to clip the mat onto the net; in this event, the mat could be designed to be reversible. Where a single mat is provided, it may be desirable to provide a movement control band such as that indicated in ghost outline at 74 in Fig. 3 to prevent the annulus "rolling" inside out when the top mat (22) is subjected to impacts in the direction of arrow A.- This movement control band may simply take the form of a sub-stantially inextensiblé cord or rope woven into the inner ~14~960 net 28.
In describing Fig. 2, reference was made to a valve 36 for inflating the annuIus. It will of course be understood that the position of the valve may vary.
Where the annulus is completely enclosed in an open woven material, the valve can be placed on the outer circumference of the annulus. Alternatively, if access is available to the inner circumference of the annulus, the valve may be placed on that circumference, for example, midway between the mats. In any event, the valve should be accessible so that the internal pressure of the annulus can be varied when the cushioning device is in use.
It should finally be noted that reference in this application to an "annulus" is to be construed broadly as lndicatlng generally a closed geometric figure. In other words, the "annulus" need not be strlctly circular.
For example, an oval annulus could be used or the annulus could have the general shape of a rectangle with rounded corners.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS-

1. A cushioning device in the form of a trampoline, the device comprising:
hollow inflatable annulus extending about an axis and defining respective end planes generally normal to said axis whereby the annulus can be supported on a horizontal surface in one of said planes with its said axis generally upright;
means supported by said annulus and including a first portion defining an exercise surface and extending across at least part of the central opening of the annulus generally in the other of said planes, and a second portion which is flexible and which extends around the annulus so that said exercise surface portion can be tensioned by varying the inflation pressure of the annulus; and, means limiting inward radial expansion of the annulus;
the annulus being capable of resiliently cushioning impacts resulting from a person jumping on a said surface and of causing the said surface to rebound subsequent to each impact, and said means providing an exercise surface being adapted to permit movement of air through the central opening of the annulus caused by depression and rebounding of said surface.

2. A device as claimed in claim 1, wherein said means providing an exercise surface comprises a net en-closing said annulus and extending across the central opening thereof in said end planes whereby said net can be tensioned to control rebounding of said surface by varying the inflation pressure of said annulus.

3. A device as claimed in claim 2, further com-prising a mat secured to said net in one of said planes and defining said exercise surface.

4. A device as claimed in claim 3, wherein two said mats are provided and are secured to portions of said net in each of said planes.

5. A device as claimed in claim 3, wherein the or each said mat is pervious to air.

6. A device as claimed in claim 1, wherein said means limiting inward radial expansion of said annulus comprises a net of annular form enclosing said annulus and dimensioned to closely fit said annulus when it has been inflated to a nominal size.

7. A device as claimed in claim 1, wherein said annulus is made of butyl rubber.

8. A device as claimed in claim 3, 4 or 5, wherein the or each said mat comprises interwoven polypropylene fibres.

9. The combination of a device as claimed in claim 1 and an exercise stand adapted to be used as a support by a person jumping on said device.

10. The combination of:
a cushioning device comprising: a hollow inflatable annulus extending about an axis and defining respective end planes generally normal to said axis;
a net enclosing said annulus and extending across the central opening thereof in said end planes, said net including first and second portions in said respective planes, and wherein one of said portions is capable of being relaxed while the other portion remains tensioned; and, a stand capable of supporting said cushioning device in an inclined position with said relaxed net portion at the outer side of the device, whereby the combination can be used as a seating unit.