Moving seat chair for exercise and rehabilitation

Abstract

A chair with a seat that moves on a curved motion mechanism in an arc relative to a base to provide flexion and extension of the knee when the user swings the seat back and forth. Telescoping structures adjust to fit different size users. A footrest in front of the chair allows the user to push against it with their feet, thus creating the swinging motion.

Description

STATEMENT REGARDING FEDERALLY FUNDED RESEARCH

No federal funds were used in the development of this invention

FIELD OF THE INVENTION

The present invention relates to exercise and rehabilitation equipment, and active sitting chairs.

BACKGROUND

The initial challenges that knee injury patients encounter involve regaining flexion and extension of the knee and reduction of swelling. A widely used approach is for the patient to lie on his/her back with their leg strapped into a knee continuous passive motion machine, such as those provided by Artromot®-E (Flexmate K500 Knee CPM, Artromot® K4 and Artromot® K3) and Optiflex (Optiflex³ knee) which guides the knee through flexion and extension. Lying on one's back is good early in the rehabilitation process, because it elevates the knee to reduce swelling. Also, the passive motion allows users to regain motion with minimal effort. However, soon after surgery patients are mobile and motion of the knee improves venous circulation; an upright posture machine is desirable for an active patient. This invention eliminates the need for lying on one's back and being strapped to a continuous passive motion machine by providing a device which will guide the user in practicing flexion and extension technique, yet enable a user to sit upright and extend and flex the knee with minimal assistance. In addition, due to the center of rotation in relation to the user, more natural flexion and extension of the knee is achieved. Finally, the user's body motion is restricted to generally one plane, thus eliminating risks associated with side-to-side motion of the body relative to the foot.

There are many “active sitting” devices ranging from simple inflated balls to chairs mounted on top of coil springs that allow a user to plant their feet on the floor and then move their buttocks in various motions. Such devices are intended to strengthen a person's core muscles. They are not, however, appropriate for rehabilitation because the body is too weak to maintain itself on these nominally unstable devices.

Another important area of applicability is keeping athletes limber or warmed up, particularly between events, when they would otherwise be sitting idle waiting for their turn to perform.

The apparatus created by following the criteria set forth is named Kneeflexer. This apparatus consists of three primary components-a base, a curved motion mechanism, and a seat. A stool, ramp, or other structure can also be used in conjunction with the feet. A user sits in the seat while the feet are supported by the floor or a structure in front of the base and seat. The motion of the seat is guided in an arc by the curved motion mechanism whose motion is about an essentially fixed point above the plane of the seat. The Kneeflexer provides guided motion so the user cannot lose control and get hurt. This device, due to its structure, also allows the user to use it as a piece of active furniture.

OBJECTS OF THE INVENTION

An object of the present invention, accordingly, is to guide the user in practicing flexion and extension of the leg joints while sitting upright.

A further object of the invention is to provide a curved motion path for a seat where the center of rotation is above the plane of the seat and is essentially a fixed point.

A further object is to position the user's leg so that the knee(s) can flex and extend through a guided range of motion.

A further object is to support the weight of the user so that no unwanted load is added to the knee.

A further object is the ability to restrict motion to generally one plane so that the user properly moves the knee.

A further object is to use adjustable structures so that the equipment can be adjusted to accommodate different size users.

A further object is that weight can be added to the equipment to increase resistance to motion.

A further object is that spring(s) can be added to the equipment to increase resistance to motion.

A further object is that a dashpot (for example, damper, shock absorber) can be added to the equipment to increase resistance to motion.

A still further object is to provide range of motion stops to limit the travel arc of the seat.

SUMMARY

The Kneeflexer consists of three primary components-a base, a curved motion mechanism, and a seat. A footrest, which may be attached to the base, can also be placed under the feet to change the type of motion the joint experiences. The curved motion mechanism radius of curvature is generally about one meter so its center of rotation is generally at a point near the head of a typical user, although different radii of curvature rails could be used for different size chairs. Thus when moving, the user's head does not appreciably translate, and they can more easily stay focused on a computer monitor, for example, while using the device. A user sits in the seat while the feet are supported by the floor or a ramp or platform or other structure in front of the base and seat. The Kneeflexer also allows the user to use it as a piece of active furniture for use by healthy people who want to exercise by moving while sitting, or by athletes who want to remain limber and warmed up between events.

DRAWINGS

The invention will now be described with reference to the accompanying drawing in which:

FIG. 1 is an isometric drawing of the structure with attached foot support;

FIG. 2 is an isometric drawing of the structure without attached foot support;

FIG. 3 is an isometric drawing of the structure with added resistance elements;

FIG. 4 is a side drawing of the structure with added resistance elements;

FIG. 5 is an exploded view isometric of the structure;

FIG. 6 shows a user operating the Kneeflexer with the knee in extension;

FIG. 7 shows a user operating the Kneeflexer with the knee in flexion;

FIG. 8 shows the Kneeflexer in the back position, for knee extension;

FIG. 9 shows the Kneeflexer in the front position, for knee flexion;

FIG. 10 shows the Kneeflexer with an inclined foot support;

FIG. 11 shows a user operating the Kneeflexer with an inclined foot support.

PREFERRED EMBODIMENT(S) OF THE INVENTION

FIGS. 1 and 2 show preferred embodiments of the invention which is made from metal, which the frame of can be extruded as a tube and then cut and bent as is well-known to those skilled in the art of metallic product manufacture. The Kneeflexer 1 has a curved bearing rail 4, bottom structure 2 with left and right sides 2a and 2b and back side 2c. Structure 3 is attached to structure 19, which in turn is attached to structure 5, which supports structure 2, which supports the user. Structure 5 acts as a bearing carriage to guide and support the curved bearing rail 4, at the bottom of structure 2 and it connects to structure 3 via structure 19. Resistance to motion may be increased by adding mass to sides 2a, 2b and/or 2c; resistance may also be increased by adding a spring or dashpot between structure 2 and structure 3. Fastener 6 provides security to lock the structural elements in a range of positions suitable for all users. It is shown as a pin, but could be a clamp or other fastening device. In addition, FIG. 1 shows a foot support structure 9, which is adjustable in height and angular position by extending and rotating tubes, which can be pinned in place once adjusted, as is common with exercise equipment. The user's feet push off the bar.

FIG. 3 shows an isometric view of the invention with added resistance elements. Structures 10a and 10b are resistance elements such as springs or dampers attached to structure 2 and structure 3. Structure 11a, 11b and 11c are posts for mass resistance elements 12 (weights) that may be added to resist motion.

FIG. 4 shows a side view of the invention with added resistance elements 10a and 10b (e.g., springs or elastomer bands); these are attached to post structures 13a and 13b on structure 2 and post structure 13c on structure 3.

FIG. 5 shows an exploded view of the Kneeflexer 1. Structure 5 supports curved bearing rail 4 to securely hold structure 2. Structure 19 fits into hole 14 on structure 3. Fastener 6 fits into hole 16a on structure 3 and any one of holes 16b on structure 19. The result is a sturdy adjustable frame and seat assembly.

FIG. 6 shows a user 15 seated in structure 2. The Kneeflexer 1 is in the back position and the knee 7 of user 15 is in extension. The user's foot 17 is placed on foot rest, structure 18.

FIG. 7 shows a user 15 seated in structure 2. The Kneeflexer 1 is in the front position and the knee 7 of user 15 is in flexion.

FIG. 8 shows structure 2 in the back position.

FIG. 9 shows structure 2 in the front position.

FIG. 10 shows Kneeflexer 1 with an inclined foot support 8.

FIG. 11 shows a user 15 seated in structure 2. The foot 17 of the user is placed on an inclined foot support 8. The inclined surface provides a continually variable elevation that enables the user to easily select the desired position for operating the chair.

Not shown is a brake, such as a simple lever, that locks the chair into position so it does not move when the user first sits in the chair. This will prevent the chair from moving and startling the user, particularly first-time users. Such brakes are well-known to those skilled in the art of wheelchairs and exercise equipment. In addition, or alternately, pins or bumpers can be removably attached to structure 2 or other elements of Kneeflexer 1 to limit range of motion.

As an example of the use and benefits of the Kneeflexer, consider the following discussion by one of the inventors, Randy Gelo:

“I am 41 years old, and a full-time karate instructor in my own school (dojo). I teach many children how to use karate as a source of inner peace and strength. In addition, I teach women's self-defense classes and special defense classes for the local police. When I was 16 I got hurt in a high school football game. Shortly afterwards, a surgeon took out the cartilage from the outside of my right knee; I had split the cartilage in half. From then until my knee replacement in Sept. 2003 I have had four surgeries on the knee. My pain was so bad that the doctor could not imagine how I could even walk because bone was grinding on bone. My ability to teach karate was in jeopardy because I could no longer demonstrate moves to my students. That is when I decided to seek a knee replacement.

“After knee replacement surgery, I could not find anything that would help me to regain flexibility in my knee. Obtaining full extension, which is needed for a normal lifestyle, was a major problem. My knee had simply frozen up with less than 30 degrees of flexion. I had to go back for surgery to have my knee manipulated into full flexion. Afterwards, although I had therapy every day, it did not help much. I had the CPM [prior art, commercially available] machine at my home; I used it every day for 4-6 hours a day for two months. It made very little difference in the flexion of my knee.

“I also had pool therapy; yet still, I barely got to about 100 degree flexion by forcing my leg to bend. After the completion of my therapy sessions, I had 102 degree bend, but only by forcing the leg to bend. I could not bend the leg using my own leg muscles. It took months before I could even ride a stationary bike, nothing seemed to work. The knee wants to enable the leg to bend about 80 degrees while pedaling a bike; I tried forcing the knee with squats and trying to sit on my shins. This created a lot of pain with no improvement.

“I tried using a yoga ball (a 3 ft. exercise ball). There was no stability and it was dangerous because there was no support when I reached my limit or end of flexion. A rocking chair worked a little in the beginning, except it was very limited in the amount of flexion I could obtain. I was lucky to bend my knee 45 degrees in either a rocker or glider chair.

“Then, in discussions with my co-inventors, we came up with the idea for the Kneeflexer. It has some resistance, caused by gravity, to help build strength with the flexibility. You are relaxed as you use it and you can control the motion with your other leg. The natural swinging (pendulum) motion can be increased ever so slowly to coax the leg into flexion, and the use of my own leg muscles to create the motion helps to strengthen them.

“With the prototype Kneeflexer, I first used a chair to prop my feet up as I used the machine. Adjusting the height affects the knee a little differently so I started using a step stool. It worked pretty well. It did not work my ankles right; I had the hardest time picking my toes up off the ground (with my foot on the ground). I then built a ramp that is adjustable. It works the ankles and the hips as well as the knee. The higher the incline the more the ankle and hip work (both flexion and extension). This combination works the best. Start with your foot near the top of the ramp, which works your extension of the knee joint and hamstring muscles in the back of the leg. As you lower the foot closer to the bottom of the ramp, you work on flexion of the knee and the quad muscles also the ankle joint and calf muscles. I use this position the most. As I warm up I start using only the one leg, and I put the other foot lower to help slightly and it also flexes that knee to a higher degree. Also, when you come forward on the Kneeflexer, try to lift your knee high on your toes; this moves the knee very effectively. The last position is about half way up the ramp and as I come forward I lift my knees as high as I can, going up on my toes. This also works on the flexion of the knee, just a little differently.

“I work on extension, first (foot at the top of the ramp). Then lower the foot on the ramp and work on flexion, find the place that pulls a little after a short time, you will be able to lower the foot and have more flexion. Now, move your foot up again and start working on lifting the knee up and go on your toes at the top of your move forward. I usually do each position for 5-10 minutes at a time, twice a day. At night I use the machine as I watch TV. I have used the machine two hours straight without much fatigue.

“The result has been nothing short of amazing. I now have full flexion and extension range in the knee, and I am once again highly effective as a karate instructor. My doctor cannot believe the rapid progress I have made with the Kneeflexer.”

Although the preferred embodiment shows a curved motion mechanism (curved bearing rail) directly under the seat of the chair, what is most important is that the center of rotation is up near the user's head; hence a curved motion mechanism could also be placed at the level of the base, or it could be a revolute joint on a frame that extends from the base to generally the level of the user's head. In addition, the bearing rail of the curved motion mechanism can be moving or fixed, attached to the base or chair respectively, with the bearing carriage fixed or moving accordingly. Alternately, the bearing rail could be replaced by other mechanisms providing generally the same motion; for example, a trolley system of wheels acting on a curved rail.

Further modifications of the invention will also occur to persons skilled in the art, and all such are deemed to fall within the spirit and scope of the invention as defined by the claims.

Claims

1. A moving seat chair comprising: a base, a curved motion mechanism with generally between about 20-40 degrees of angular motion, a seat.

2. The moving seat chair of claim 1 where the curved motion mechanism is comprised of: A bearing rail, a bearing carriage that moves on the rail

3. The moving seat chair of claim 2 where the bearing rail is attached to a structure mounted to the seat, and the bearing carriage is attached to a post attached to the base.

4. The moving seat chair of claim 2 where the bearing carriage is attached to a structure mounted to the seat, and the bearing rail is attached to the base.

5. The moving seat chair of claim 1 where the curved motion mechanism is comprised of one or more individual curved sections.

6. The moving seat chair of claim 1 where the curved motion mechanism's radius of curvature is constant.

7. The moving seat chair of claim 1 where the curved motion mechanism's radius of curvature varies.

8. The moving seat chair of claim 1 with weight support structures, and weights on the weight support structure.

9. The moving seat chair of claim 1 with springs generally attached to the seat and to the base.

10. The moving seat chair of claim 1 with dampers generally attached to the seat and to the base.

11. The moving seat chair of claim 1 with a foot-support structure in front of the chair.

12. The moving seat chair of claim 1 with an adjustable length structure between the base and the chair.

13. The moving seat chair of claim 1 with adjustable range of motion stops.

14. A chair comprising a seat, a rail support structure, one or more curved bearing rails attached to the rail support structure, one or more bearing carriages which move on the curved rails, and a base frame that supports the chair above the ground.

15. The chair as claimed in claim 14 where the bearings are ball or roller element bearings.

16. The chair as claimed in claim 14 where the bearings are sliding contact bearings.

17. The chair as claimed in claim 14 where the bearings are wheels which roll on the curved rails.

18. The chair as claimed in claim 14 with a ramp, stool, or step near the chair for the user to place their foot on to achieve different ranges of motion.

19. The chair as claimed in claim 14 with a brake to hold the chair in position while the user sits in it.

20. The chair as claimed in claim 14 where the support frame is adjustable in height.