Exercise devices – Having specific electrical feature – Monitors exercise parameter
Reexamination Certificate
1999-10-18
2001-07-31
Richman, Glenn E. (Department: 3764)
Exercise devices
Having specific electrical feature
Monitors exercise parameter
C482S001000, C600S595000
Reexamination Certificate
active
06267709
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an isokinetic resistance apparatus for use in exercise, rehabilitation and physical performance testing equipment.
BACKGROUND OF THE INVENTION
With an isometric resistance apparatus, muscles are caused to act against a fixed object. In contrast, with an isokinetic resistance apparatus, muscles are caused to act through a range of movement at a constant rate of speed. Principles of isokinetic resistance are potentially applicable to exercise equipment, rehabilitation equipment and physical performance testing equipment.
SUMMARY OF THE INVENTION
What is required is an isokinetic resistance apparatus.
According to the present invention there is provided an isokinetic resistance apparatus which includes a motor having an output shaft and a motor controller adapted to control power to the motor to maintain a first constant rotational speed of the output shaft. A driven shaft is coupled by a drive linkage to the output shaft of the motor, such the output shaft of the motor imparts movement to rotate the driven shaft in a first rotational direction at a second constant rotational speed. A force receiving member is coupled by a force transmitting linkage with the driven shaft. The force transmitting linkage includes a unidirectional clutch adapted to move freely about the driven shaft in a second rotational direction and engage the driven shaft in the first rotational direction. A force exerted upon the force receiving member tending to move the unidirectional clutch faster than the second constant rotational speed in the first rotational direction is transmitted through the driven shaft and the drive linkage to the output shaft of the motor. The motor controller adjusts power to the motor to compensate for such force and proportionately increase resistance to maintain the first constant rotational speed of the output shaft.
The isokinetic resistance apparatus, as described above, offers a proportional resistance to a person's input while maintaining a set rotational velocity for that motion.
Although beneficial results may be obtained through the use of the apparatus, as described above, even more beneficial results may be obtained when the first constant rotational speed of the output shaft is greater than the second constant rotational speed of the driven shaft, with a speed reduction being effected between the drive linkage. It is preferred the drive linkage utilizes one or more worm gears as there are inefficiencies inherent in a worm gear reducer. It is also preferred that this speed differential be between a range of 20:1 and 60:1. For best results, it is preferred that the range be equal to or greater than 30:1. Due to friction, most worm gears with ratios of 30:1 or higher are self locking so that the low speed driven shaft cannot backdrive the high speed output shaft regardless of the torque applied. This self-locking nature of the gear reducer is used to prevent the torque generated by the subject from increasing the speed of the driven shaft. This allows a very low power motor to resist the torque generated by the test subject.
Although beneficial results may be obtained through the use of the isokinetic resistance apparatus, as described above, in the preferred embodiment resistance can be made bidirectional. This is accomplished by coupling the force receiving member with an input shaft. A force applied to the force receiving member in a first direction rotates the input shaft in a first input direction, a force applied to the force receiving member in a second direction rotates the input shaft in a second input direction. Two force transmitting linkages are provided. A first force transmitting linkage is provided between the input shaft of the force receiving member and the driven shaft. The first force transmitting linkage includes a first unidirectional clutch adapted to move freely about the driven shaft in the second rotational direction and engage the driven shaft in the first rotational direction when force is applied to the input shaft in the first input direction. A second force transmitting linkage is provided between the input shaft of the force receiving member and the driven shaft. The second force transmitting linkage includes a second unidirectional clutch adapted to move freely about the driven shaft in the second rotational direction and engage the driven shaft in the first rotational direction when force is applied to the input shaft in the second input direction. This configuration allows for resistance in both the clockwise and counter clockwise (flexion/extension) directions, without changing rotational direction of the output shaft of the motor.
There are various technologies that can be used for torque transfer linkages without effecting overall performance. There is hereinafter described a force transmitting linkage that includes a bevelled pinion gear secured to the force receiving member that meshes with a bevelled spider gear rotatably mounted to the driven shaft. This form of linkage has been selected as it is viewed as being one of the most direct form of linkages. Alternative linkages can be devised using chains, belts, pulleys, hydraulics or various combinations of the same. The configuration described allows a relatively small motor to absorb substantially higher forces than would otherwise be possible. This allows for a comparatively small and lightweight product.
Although beneficial results may be obtained through the use of the isokinetic resistance apparatus, as described above, even more beneficial results may be obtained when a force monitor is coupled to the force receiving member. The force monitor is adapted to measure force applied to the force receiving member, and thereby provides an objective measurement of performance. There are various technologies that can be used to measure force. The one that will hereinafter be further described is a load cell technology. The load cell technology is preferred because the input shaft of the gearbox can easily be fitted with a load cell to measure torque input to create an inexpensive isokinetic dynamometer.
REFERENCES:
patent: 4628910 (1986-12-01), Krukowski
patent: 4934694 (1990-06-01), McIntosh
patent: 5830160 (1998-11-01), Reinkensmeyer
patent: 5919115 (1999-07-01), Horowitz
patent: 6155993 (2000-12-01), Scott
Jacques Gary
King Brent Warren
Moore Ken Wilbur
Tremaine Daren Paul
Canadian Space Agency
Christensen O'Connor Johnson & Kindness PLLC
Richman Glenn E.
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