Control system and method for exercise machine
An exercise machine for simulating running has a frame having a forward portion and a rear portion. A shoulder harness is connected to the forward portion of the frame for supporting the torso of the user and preventing the forward movement of the user's body. Two levers are pivotally connected to the rear portion of the frame, and a pedal assembly is connected to each lever, for receiving the foot of the user. In one embodiment, a passive means for generating a counter force is connected between the lever and the rear frame, such as an elastic band, spring, torsion bar or hydraulic cylinder. In another embodiment a hydraulic or pneumatic actuator is connected between each lever and the frame, and an active control system is operatively connected to each actuator; the active control system being configured to generate a counter force to the user according to a preselected program.
This application relates to the existing strength training equipment that simulates the motions of running. The majority of strength and resistance training weights for the counter-force. This application concerns the application of passive and active systems to replace the effect of conventional weights.
BACKGROUNDApplicant Johnston is one of the inventors of U.S. Pat. No. 5,941,804, “Exercise Machine for Simulating Running,” which patent is incorporated into this application by reference in its entirety. We use the device disclosed in U.S. Pat. No. 5,941,804 (“the runner”) to analyze the dynamics of a running machine, since the runner has been proven to be effective in training for fast runs and fast take-offs. Nevertheless, the power curve developed by the runner using weights for counter force is not ideal for training. A desirable power curve would be linear; that is, the force remains nearly constant for a given displacement of the exercise apparatus by the user. This can be accomplished by implementing control systems that replace the effect of conventional weights. Such control systems may be passive, or, they may be made active, so that the counter-force may be varied in a controlled way during the exercise.
SUMMARYWe disclose an exercise machine for simulating running, comprising a frame, the frame having a forward portion and a rear portion. A shoulder harness is connected to the forward portion of the frame for supporting the torso of the user on its ventral side, and preventing the forward movement of the user's body. Two levers are pivotally connected to the rear portion of the frame, and a pedal assembly is connected to each lever, for receiving the foot of the user. In one embodiment, a passive means for generating a counter force is connected between the lever and the rear frame, such as an elastic band, spring, torsion bar or hydraulic cylinder. In another embodiment A hydraulic or pneumatic actuator is connected between each lever and the frame; and, an active control system is operatively connected to each actuator; the active control system being configured to generate a counter force to the user according to a preselected program.
DESCRIPTION OF DRAWINGS
Some of the drawings have dimensions. The dimensions are given merely to illustrate typical embodiments and do not limit the scope of the claims.
DETAILED DESCRIPTION
The values of pedal movement to rotation angle can directly be retrieved. One can see that the maximum angle of 60 degrees brings the weight nearly horizontal to the axis of its rotation resulting in the maximum value for the force factor (maximum leverage).
The graph in
A purely passive control system can change the displacement-load relationship in a desirable direction. The embodiments discussed below use one of the following passive means for generating a counter force. The weight may be replaced by, for example, different sets of elastic bands or cylindrical springs, torsion bars or cylindrical helical springs, or pneumatic or hydraulic actuators.
Replacement of the Weights by Elastic Bands and Cylindrical Springs.
An elastic band or spring has the characteristic that the force increases as it is extended. This can be compensated for by the movement of the attachment arm (200). During the movement, the moment of the lever gets shorter, which causes a smaller elongation of the bands or springs, thus compensating the increasing spring or band load partially.
In another embodiment, a belt drive is added between two wheels, as shown in
The resulting gear ratios and resulting turn increments of the driven wheel are given in Table 1 below. One can clearly see that the second wheel (280) wheel turns in different increments than the first wheel (270), dependent on the location of the pedal lever (150). In Table 1, the increments have been calculated for constant turn increments of the primary wheel of 5 deg each.
The bands or springs (230, 240) are connected to the extension arm (200), now fixed to the axis of the second wheel (280).
When the athlete starts to stretch his leg, the driven wheel (280) turns faster than the driving wheel (270) which is directly connected to the lever (150) holding the pedals.
At the end of the movement, when the athlete's leg is stretched, the driven wheel (280) turns slower than the driving wheel (270), thus exerting more force to stretch the bands or springs. The resulting force factors are shown in the next graph in
One can clearly see that the curve is reciprocal to the gear ratio.
This shows that we have full control of the spring or exercise band (230, 240) behaviors by means of the wheels (270, 280) we select. The variables involved are the dimensions of the wheels (270, 280), the location of the attachment points (235, 245) on the frame (110), and the location of the attachment to the driven wheel (280). The latter may be made by choosing the length of the extension arm (200) appropriately, or by choosing different attachment points (210, 220).
The load resistance may also be provided by one or more torsion bars in place of springs or elastic bands. The general connection of a torsion bar is shown in
Another passive control system is shown in
All of the above systems have one in common: they are resistance training equipment and the resistance can only be pre-set before the athlete starts with the exercises. An active control system makes it possible to actively control the counter force and vary it over the total range of movement. Active control systems for exercise equipment are discussed in pending U.S. patent application, Ser. No. 10/032,993, “Exercise Recording and Training Apparatus,” published on Jul. 11, 2002 under pub. No. US 2002/0091031 A1, now U.S. Pat. No. 6,659,913. patent application Ser. No. 10/032,993 is incorporated into this application by reference in its entirety.
The pneumatic cylinders may be substituted by other equivalent active control components, such as hydraulic cylinders or linear electric motors.
Claims
1. An exercise machine for simulating running, comprising:
- a frame, the frame having a center portion and a rear portion,
- two levers pivotally connected to the rear portion of the frame,
- a pedal assembly connected to each lever arm, for receiving the foot of the user,
- an extension arm connected to each lever at the pivotal connection of the levers to the rear portion of the frame; and,
- a passive means for generating a counter force; the passive means connected between each extension arm and the rear frame.
2. The exercise machine of claim 1 where the means for generating a counter force is at least one elastic band connected between each extension arm and the rear frame.
3. The exercise machine of claim 2 where the attachment points of the elastic band to the extension arm and the rear frame are selectively variable.
4. The exercise machine of claim 1 where the means for generating a counter force is at least one elastic band connected between each extension arm and the rear frame and further comprising:
- a circular sheave connected to the lever arm concentric with the pivot of the lever arm; and,
- the elastic band configured to seat in the groove of the circular sheave as the circular sheave rotates.
5. The exercise machine of claim 1 where the means for generating a counter force is at least one elastic band connected between each extension arm and the rear frame and further comprising:
- an eliptical sheave connected to the lever arm concentric with the pivot of the lever arm; and,
- the elastic band configured to seat in the groove of the eliptical sheave as the eliptical sheave rotates.
6. The exercise machine of claim 1 where the means for generating a counter force is at least one spring connected between each extension arm and the rear frame.
7. An exercise machine for simulating running, comprising:
- a frame, the frame having a center portion and a rear portion,
- two levers pivotally connected to the rear portion of the frame,
- a pedal assembly connected to each lever arm, for receiving the foot of the user,
- a passive means for generating a counter force; the passive means connected between the levers and the rear frame.
8. The exercise machine of claim 7 where the passive means for generating a counter force is a torsion bar.
9. The exercise machine of claim 7 where the passive means for generating a counter force is a flat spring.
10. An exercise machine for simulating running, comprising:
- a frame, the frame having a center portion and a rear portion,
- two levers pivotally connected to the rear portion of the frame,
- a pedal assembly connected to each lever arm, for receiving the foot of the user,
- a first eliptical wheel connected coaxially with the pivot of the lever;
- a second eliptical wheel connected rotabably to the rear frame;
- the first and second eliptical wheels rotatably connected by a belt;
- the first and second eliptical wheels postitioned so the their long axes are perpendicular;
- a passive means for generating a counter force; the passive means connected between the first eliptical wheel and the rear frame.
11. The exercise machine of claim 10 where the a passive means for generating a counter force is a torsion bar.
12. The exercise machine of claim 10 where the passive means for generating a counter force is a flat spring.
13. The exercise machine of claim 1 where the passive means for generating a counter force is a pneumatic cylinder.
14. An exercise machine for simulating running, comprising:
- a frame, the frame having a center portion and a rear portion,
- two levers pivotally connected to the rear portion of the frame,
- a pedal assembly connected to each lever arm, for receiving the foot of the user,
- an extension arm connected to each lever at the pivotal connection of the levers to the rear portion of the frame; and,
- an active means for generating a counter force; the active means connected between each extension arm and the rear frame.
15. The exercise machine of claim 14 where the active means for generating a counter force further comprises:
- a pneumatic cylinder;
- a pressure sensor connected to the pneumatic cylinder;
- a pressure control valve connected to the pneumatic cylinder;
- a displacement sensor connected to the pneumatic cylinder;
- the pressure sensor, the pressure control valve and the displacement sensor connected to a computer;
- the computer executing a stored program for: measuring and displaying on the computer the displacement of the cylinder; measuring and displaying on the computer the pressure in the pneumatic cylinder; and, according to the stored program, computing and displaying on the computer the counter force generated when the exercise machine is operated.
16. The exercise machine of claim 15, further comprising:
- a pressure amplifier connected between a source of pressure and the pressure control valve.
17. The exercise machine of claim 15, further comprising:
- a position-limit valve connected between a source of pressure and the control valve.
Type: Application
Filed: Sep 7, 2005
Publication Date: Mar 8, 2007
Inventors: Allen Johnston (Tuscaloosa, AL), Eike Mueller (Pan Yu)
Application Number: 11/220,798
International Classification: A63B 21/06 (20060101); A63B 21/08 (20060101);