Exercise apparatus
An exercise apparatus comprising a rigid movable booster bar having two flexible elastic elements attached to the booster with an attachment. The attachments are spaced from each other and configured to allow winding the elastic element upon the booster bar by rotating the booster bar. Each flexible elastic element comprises at least two stages of flexible shock cords, with the stages disposed serially along the length of the flexible element, with adjacent stages having a different elastic stiffness.
(Not applicable)
FEDERAL RESEARCH STATEMENT(Not applicable)
BACKGROUND OF INVENTIONThe use of exercise machines has proliferated in the last decade or so. In general there are two main classifications of such machines—those primarily intended for use in a commercial sports center and those primarily intended for use in the home. Those intended primarily for use in a sports center are quite complex, are structurally heavy and bulky, are usually attached to the floor or the wall, and oftentimes have a complicated arrangement of levers, pulleys, weights, etc. Normally they may also be adjustable for different users having different physical strengths. Those intended primarily for the home are simpler, lighter, much less expensive but still adjustable to some degree.
One such exercise machine comprises flexible elastic shock cords, usually two, which are stretched by a force exerted by the user. As a cord is stretched more and more, the force required to stretch it increases more and more. One end of the shock cord is attached to a fixed structure and the other end attached to a booster bar adapted to be moved by the user's arms or legs as the cord is stretched by the user. As a natural consequence of the size of the user the stretched length of the shock cord will be substantially constant for a given user but will be different for a different user. Also as a natural consequence of the physical characteristics of shock cords the force-length curve is an inverse exponential when the force is displayed as the abscissa. Thus the maximum force required for a given user to stretch his arms or his legs to their fullest extent depends on the characteristics of the shock cord and also on the ratio of the stretched length to the unstretched length of the shock cords. Since a different user having a different physical size or strength will require a different ratio of stretched length to unstretched length it becomes necessary to provide some means for shortening or lengthening the unstretched length. This is normally effected by means of clamps; however the clamps oftentimes damage the shock cord and thus make the shock cord essentially unusable after a given number of adjustments.
In U.S. Pat. No. 5,125,649, to Conrad Fuller (Fuller) (incorporated hereby by reference) is an exercise machine with a booster bar that mitigates the problems of adjustment found in previous systems, where the stretched and unstretched length of the shock cord are adjusted by the user without the use of clamps or tools. In the Fuller system a booster bar is attached to pair of flexible elastic shock cords, which have their other ends attached to fixed structural members. The user exercises his arms or his legs by repeatedly pushing against the booster bar, thus stretching and unstretching the shock cords. The unstretched (and thus the stretched) length of the shock cords is adjusted by rotating the booster bar about its axis, thus winding or unwinding, the shock cords around the booster bar. This, in turn, adjusts the force required to stretch the shock cords to a given dimension.
However, the Fuller system is still not adequate in providing an exercise machine that can be used by different users of different size and with different strengths. This is due to the force-length properties of braided shock cords, which as mentioned in the Fuller patent can be represented as an inverse exponential curve. Basically as the cord is stretched, the stretching or return force is approximately constant or increases proportionally at a modest rate. But, as the maximum stretching length for the cord is approached, the return force increases much more rapidly, where (at least as perceived by the user) even significant increases in the force will not cause the cord to stretch further. Thus, the perceived effect by the exerciser is a movement that is suddenly or abruptly stopped. In other words, as the cord is stretched, the user at first perceives a constant or modest increase in force as determined by the stiffness of cord until a point is reached where the stretching or return force increases rapidly with no or little increase in the stretching length. At this point the exerciser perceives an abrupt stop and cannot continue extending the cord.
Basically, a braided shock cord will extend, depending on the particular cord construction, up to 100% or more of its unstretched length, until it reaches a this “abrupt stop” point where under higher and higher forces it will stretch only a small amount.
As described in the Fuller patent, the length of the shock cords can be adjusted by wrapping them around the booster bar. However, when fully unwound to lengthen stretching cord and allow the user to stretch the cords a greater distance before reaching the abrupt stop, the initial force and the force over the most of the length of the stretching is also reduced, which reduces the exercise effect. To increase the force and the exercise effect, the stretched length of the shock cord can be shortened by wrapping the cord around the booster bar. But if the stretching length is shortened too much this will prevent the user from extending the cord to the length required for the exercise. This is because the user is attempting to stretch the shortened shock cord beyond its design and the “abrupt stop” is encountered before the exercise movement is completed.
A partial solution is to use shock cords of different elastic, i.e., stiffness, properties. “Stiffness” or “stiff” is a measure of the amount of elastic return force obtained for a given amount of stretching. For a strong person, a machine with stiffer cords is chosen so that the stretching force is high at the beginning during the stretch. Because the cord does not have to be shortened excessively, and the abrupt stop isn't reached during exercise movements, the person is allowed to stretch to the desired length for the exercise. A weak person could not use such a machine, because, even when the cords are fully unwound to the full length, the stretching force is too high, and he would only be able to successfully accomplish few or none of the exercises. For the weak person, a machine with less stiff or compliant shock cords would be suitable. However, the strong person would not find this machine suitable, because she would be able to extend the cords as far as she can extend her limbs without feeling adequate increase in the stretching force. Winding the cords around the booster bar to increase the force, may result in insufficient stretching length where the abrupt stop will likely be reached during routine exercises. Exercises with long stretches then become difficult or impossible.
In summary, the Fuller machine has the ability to change the stretching length of the shock cord, which enables a person to vary the stretching force and to do a variety of exercises, from short stretches to long stretches. But, the advantage is not fully met if the stiffness of the shock cords does not well match with a user's size and strength. This is a particular problem as the user becomes stronger over time, requiring the user to obtain a new machine or rebuild the old one.
SUMMARY OF INVENTIONAn aspect of the present invention is an exercise apparatus comprising a rigid booster bar with two flexible elastic elements attached to the booster with an attachment. The attachments are spaced from each other and configured to allow winding the elastic element upon the booster bar by rotating the booster bar. Each flexible elastic element comprises at least two stages of flexible shock cords, with the stages disposed serially along the length of the flexible element, with adjacent stages having a different elastic stiffness.
The present invention is an apparatus that improves upon the Fuller machine by extending the range of user size and strength that can be matched to a particular apparatus. Any one apparatus is optimal for a wider range of user size and strength. The apparatus of the present invention can be used like the Fuller machine, by stretching and unstretching flexible elastic elements by means of a booster bar, and the user can change the stretching length of the elastic elements by wrapping same upon the booster bar. However, the present apparatus has replaced the shock cords in Fuller machine with improved flexible elastic elements that have a more optimum force-length curve. In addition, the apparatus of the present invention, because of its unique construction, can be used in different ways.
The improved elastic elements can be wound and unwound upon the booster bar to adjust force, but with a small or minimal amount of winding required to obtain a higher stretching force. This leaves a larger stretching length and lessens the probability that the abrupt stop will be reached during an exercise movement. The cord can be stretched to high stretching forces without encountering an abrupt stop, even in exercises requiring high force and a long stretch.
Not only is the abrupt stop essentially eliminated, but the force-length profile is improved. During a stretch, higher forces are obtained at a slower rate. In addition, the stretching force encountered in an exercise movement is over a wider range, allowing a user to start the stretch at a lower force and stretch up to and sustain a higher force, a force that cannot be sustained if the high force comes on quickly or abruptly. This allows a user to sustain higher forces and gain more strength building benefit than in previous devices. In previous devices, one could not gradually obtain a high stretching force when starting a low stretching force, because the abrupt stop would be reached before the high force was obtained.
In addition, for any given apparatus a stronger user will be able to derive more exercise and obtain and sustain higher forces, and a weaker user has lower forces available that allows accomplishment of more exercises. Both weaker and stronger users benefit from the better force-length profile. Thus, it is possible by practice of the invention that a single apparatus can be provided that better meets the needs of a person as he grows stronger, and be more easily adjusted for wider variety of people, including children, adults, athletes, sedentary persons, and persons with physical disabilities.
The apparatus of the present invention achieves the above advantages in part by having a rigid booster bar with a flexible elastic element constructed with multiple stages of braided elastic stretch cords attached to each end. By “staged”, is meant that the length of each stretch cord is subdivided into at least two regions or stages. Each stage is constructed with one or more braided shock cords, such that each adjacent region has a different stiffness from its neighboring or adjacent stages. Thus the stages are attached in series end to end such that the stiffness of the elastic element changes from stage to stage. This contrasts with the Fuller machine where the elastic cords are designed with essentially the same stiffness for their entire length.
Because the flexible elastic element is staged, with high stretch force a high elongation can be obtained without encountering an abrupt stop. This is in part to the fact that the large stretching forces can be obtained with a minimum of wrapping around the bar, allowing more of the length of the elastic element to be stretched.
In addition, as the flexible element is stretched, the lengthening or elongation is not distributed evenly along it length. During a stretch all of the stages will begin to elongate, but the less stiff stages will initially stretch more than the stiffer stages. As the less stiff stages approach their maximum elongation, more elongation will then occur in stiffer stages. Thus, elongation is serially transferred from the less stiff stages to the stiffer stages, with the stiffest stages being the last to sustain significant elongation. The stiffest stage is designed to sustain the maximum design force of the equipment without reaching its maximum elongation required for exercise. Thus, at any elongation during exercise, there are always one or more stages that have not reached maximum elongation, thus eliminating an abrupt stop.
Furthermore, at the beginning of the stretch the force is mostly determined by the least stiff or most compliant stage, but the elastic element can be stretched to a high final force as determined by the stiffest stage. By the staged system a rather even force profile can be provided that extends from a low stretching force of stiffness to a stiffness, and this profile can be predetermined by the selection of different stiffnesses of multiple stages.
Reference is now made to
The stages are constructed of braided elastic cords 23, also known as “shock cords”, or “bungee cords”. These cords have an inner core of an elastomer, such as latex, covered with a braided sheath. Shock cords are widely available in various diameters and stiffness. Any diameter can be used. Diameters between ¼ and ½ inches have been found suitable.
A stage may comprise one shock cord or multiple shock cords attached together in parallel. Multiple shock cords in a stage may be of the same stiffness and diameter or different stiffness and diameter. In addition, the thickness and diameter of shock cords in the different stages may be the same or different.
A requirement of the present invention is that the elastic element comprise at least two adjacent stages that have a different stiffness. The varying stiffness of the stages can be provided by changing the number of shock cords in the stages. Thus, for example, a first stage may comprise one shock cord, a second stage or two shock cords, and third stage or three shock cords. The stage may be in any order. It is preferred that the stage with fewer shock cords be adjacent to the booster bar to ease the wrapping of the elastic element around the bar easier. However, putting stiffer stages adjacent the booster bar is also contemplated. In the table below is shown various illustrative combinations, showing the number of shock cord strands in each stage, with the first being at the near end 18 nearest to the booster bar. Also in the Table, there are references to Figures illustrating that particular combination.
The stiffness can also changed by changing the stiffness of the cords used in the stages. Thus, for example, a two-stage flexible element can be constructed with ¼ in. cord in stage 1, and ½ inch cord in stage two. Referring to
There must be at least two stages having different stiffness in an elastic element. The more stages, the more even will be force-length profile, but the number of stages is limited by practical construction limitations. More stages may be recommended where there is a large difference between the number of cords between the most compliant and the stiffest stage. The length of the stages can be any suitable length. The stages may of the same length or one stage may be lengthened or shortened relative to the others.
Where there are three or more stages, stages may have the same or different stiffness as long as there are at least two stages that are adjacent and have different stiffness. Combined length of the stages, or the total length of an elastic element is consistent with the nature of the exercises to be performed, the size of the user and the construction of the opposing element. For an exercise device as in
The stages are attached to each other end to end in series by a suitable attachment system 21. Methods for attaching cords to one another at the ends of the stages can be any suitable method, and include any combination of: tying with knots, thermally fusing, gluing, molding together without or with separate elements, sewing, using crimped or other metal fasteners, wrapping or fixing material around the cords (e.g., wire ties, tape, string, shrink-wrap, wire). One or more shock cords can be continuous through adjacent stages. For example, a single cord may extend through all of the stages, or through two or more stages. (See
The attachment to the booster bar may be the same as in the Fuller machine. The attachment is preferably placed so that the elastic elements can be wound upon a region of the booster bar between the attachments, with handgrips outside of the attachments at the ends of bar, as illustrated in
The near ends 18 of the elastic elements 15 are attached to the booster bar 13, by a fixed attachment 17 to permit winding, so that the stretched length of the elastic element can be adjusted by rotating the booster bar and thus winding cords of the stages around the booster bar to any degree desired. The attachment may also optionally include a length of nonstretching flexible cord between the cord and the booster bar.
Optionally, handgrips 37 (
The booster bar may be any suitable bar-like structure of suitable strength and dimension that functions as described. The bar may be solid or tubular, and may be of metal (aluminum, steel, aluminum, etc.) wood, polymeric materials (fiber reinforced polymers, engineering plastics, etc.) or any other suitable material. The bar may a single unit, assembled from separate parts, or may be constructed to allow disassembly into smaller parts for transport. This may be by means of telescoping tubes or the like. The cross-section is circular, or non-circular (oval, polygonal, polygonal with rounded edges, ridged, knurled, etc.), but sufficiently round to allow winding of the elastic members around the booster bar.
The structure and placement of the opposing member and of booster bar are such to work the elastic elements while performing an exercise movement. The opposing member for an exercise can be placed, for example, under one or both feet (
An opposing member may be any suitable structure, including those illustrated herein, and the structures disclosed in Fuller, U.S. Pat. No. 5,125,649. As an example, the opposing member 25 may also be a flexible sling (
Any configuration of booster bar, elastic elements, opposing member, and respective attachments are contemplated as long as the booster bar and opposing member are held in a moving or fixed positions to oppose each other in a stretching exercise movement. For example, the booster bar can be held in the hands, with an opposing member sling under a foot or feet (
The shock cords are preferably seized, fused, taped, or the like, at each end to prevent unraveling. The near ends of the elastic elements are also preferably attached to the booster bar by a system that guards against sharp edges or pressure points bearing against the elastic elements which could cause chafing, which provides positive configurations for preventing the shock cords from pulling away from the booster bar regardless of the force exerted by a user, for preventing relative circumferential movement between the booster bar and the point of attachment of the shock cords to the booster bar, and allowing a user to at least partially wind the shock cords around the booster bar by rotating the booster bar about its long axis.
An exemplary configuration comprises a booster bar which is hollow, at least near its ends, with a hole near each end passing through the wall. The near ends of the shock cords are threaded through respective holes and out through the open ends of the booster bar; providing a first knot at the near end of each shock cord. Each shock cord is pulled back such that the first knot is positioned inside the booster bar adjacent the hole; and a second knot is tied in each shock cord at a position adjacent the booster bar. As a variation, each shock cord, after having its first knot pulled back inside the booster bar, is looped around the booster bar, and passed under itself, thus providing the second knot.
An alternate method comprises utilizing a booster bar which bar has a hole, near each end, passing completely through the bar; threading the near ends of the shock cords through respective holes; providing a first knot at the near end of each shock cord adjacent the hole, and tying a second knot in each shock cord at a position adjacent the booster bar. The same variation as noted above may also be used in this configuration.
The distal ends 26 are attached to the opposing element by any suitable method, and can comprise knots, loops, metal or polymeric ties, rings or ties, sewing, wrapped tape, and the like.
It is also contemplated for each elastic element to join two, or more, elastic elements into a single elastic element. Such a multiple flexible element would comprise multiple elements at each end of the booster bar attached in a parallel arrangement.
While this invention has been described with reference to certain specific embodiments and examples, it will be recognized by those skilled in the art that many variations are possible without departing from the scope and spirit of this invention, and that the invention, as described by the claims, is intended to cover all changes and modifications of the invention which do not depart from the spirit of the invention
Claims
1. An exercise apparatus comprising: each flexible elastic element comprising at least two stages of flexible shock cords, with at least two stages having a different stiffness, the stages attached to each other end to end so that they are disposed serially along the length of the flexible element, a distal end of each flexible element configured for a moving or fixed attachment to allow stretching of the flexible element.
- a rigid movable booster bar;
- two flexible elastic elements, each attached to the booster bar at a near end with an attachment, the attachments spaced from each other and configured to allow winding the elastic element upon the booster bar by rotating the booster bar, to allow a gripping region on the booster bar,
2. An exercise apparatus as in claim 1 wherein the stages comprise one or more flexible shock cords.
3. An exercise apparatus as in claim 2 wherein two stages with different stiffness have a different number of shock cords.
4. An exercise apparatus as in claim 2 wherein two stages with different stiffness comprise shock cord strands of a different stiffness.
5. An exercise apparatus as in claim 1 wherein a distal end of each flexible element is attached to a fixed object.
6. An exercise apparatus as in claim 1 wherein a distal end of each flexible element is attached to an opposing member.
7. An exercise apparatus as in claim 6 wherein the opposing member is movable.
8. An exercise apparatus as in claim 6 wherein the opposing member is fixed.
9. An exercise apparatus as in claim 6 wherein the opposing member is a flexible strap with the distal ends attached to either end of the strap.
10. An exercise apparatus as in claim 9 wherein the flexible strap is elastic or non-elastic.
11. An exercise apparatus as in claim 6 wherein the opposing member is a nonflexible bar or platform.
12. An exercise apparatus as in claim 11 wherein the opposing member is configured the same as the booster bar.
13. An exercise apparatus as in claim 1 wherein the stages are attached to each other by one or more of knots, sewing, glue, fusion, clamps, ties, tape wrapping, and molded structures.
Type: Application
Filed: Jun 9, 2006
Publication Date: Dec 13, 2007
Inventor: Conrad R. Fuller (Salt Lake City, UT)
Application Number: 11/450,114
International Classification: A63B 21/02 (20060101);