Not applicable
The present invention relates to mechanical devices for applying beneficial stress to the body for prevention of osteoporosis or stimulation of muscle and tissue.
Bones in the human body are subject to constant remodeling in response to stresses that promote bone formation. Such stresses may occur during natural physical activity or exercise.
One possible treatment for osteoporosis or bone loss may be machines which apply stress to a patient, for example, by means of the patient standing on a vibrating platform that simulates the stresses that would occur through natural activities. Such machines may be useful for those who are unable otherwise to obtain sufficient physical activity or as a method of supplementing physical activity in a more concentrated manner.
An early device, described in U.S. Pat. No. 5,046,484 issued to C. Andrew L. Basset provides a platform that is periodically raised by means of the action of a cam and then dropped abruptly to simulate the natural footfall of an individual. In this case, the stress is caused by rapid deceleration of the platform at the bottom of its travel. The impact rate may be determined by measuring a natural rate of heel strikes when a patient is walking and is determined by the regular rotational speed of the motor.
U.S. Pat. No. 6,659,918 issued to Hans Schiessl uses a crank arm to impart a simple harmonic motion to a similar platform at a frequency dictated by the rotational speed of a motor.
U.S. Pat. No. 5,273,028 issued to Kenneth J. McLeod describe an alternative drive mechanism in which the platform is mounted on springs and driven at a resonant frequency by an electromagnetic actuator or rotating eccentric mass. Such systems provide a single excitation frequency to the platform whose ultimate movement is determined by the resonance of the system including the spring constant of the springs and the mass of the patient.
The present inventor has recognized that the body is a complex system of resonant structures having linear and nonlinear elements. For example, lower lumbar vertebrae and hip joints are parts of different resonant structures and thus have different resonant responses. For this reason, inducing desirable levels of stress or muscle activity in different structures may require excitation simultaneously at two or more frequencies at different controlled amplitudes. Current systems which provide a single frequency of excitation, or in the case of an impact system, a single band of frequencies whose amplitudes are essentially uncontrollable, may provide less than optimal excitation of body structures.
Specifically then, the present invention provides an apparatus for mechanical stimulation of the body, including a footplate for receiving feet of a standing person and a actuator attached to the footplate to impart a pattern of vertical motion to the footplate consisting of periodic accelerations at predetermined different times with predetermined different amplitudes.
It is therefore one is an object of the invention to apply substantial energy at multiple different frequencies of vibration to a person as determined by the actuator.
The accelerations may be in a frequency range from 10-100 hertz.
Thus, it is an object of the invention to provide a system that may provide frequencies thought to be desirable for the stimulation of bone strength.
The apparatus may include an adjustment means for changing the time between the periodic accelerations and thus a frequency range of the accelerations.
It is thus an object of the invention to provide a system that allows adjustment of the stimulation frequency.
The actuator may produce a predetermined displacement of the footplate independent of the weight of a body.
It is thus an object of the invention to provide a system that may work with a variety of different patients without adjustment of springs or weights.
The periodic accelerations may be selected to accommodate different resonant modes of different structures of the body.
It is thus an object of the invention to provide a system that recognizes that the body is composed of loosely coupled different resonant structures.
The actuator may include at least one cam having a non-circular profile.
It is thus an object of the invention to provide a flexible, yet simple method of providing an arbitrary multi-frequency excitation pattern to the footplate.
The invention may include cam followers attached to the footplate and resting against multiple synchronously rotated and phased cams.
It is thus an object of the invention to provide a system that minimizes the mass and structure on the moving footplate.
The cam followers may be compliant to control the acceleration of the footplate.
It is thus an object of the invention to reduce high frequency components to the patient, such as may provide for less therapeutic benefit.
The invention may provide a speed-controllable motor for adjustment of the time between the periodic accelerations.
Thus, it is an object of the invention to provide an absolute frequency control independent of the particular patient.
These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention.
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A set of four cams 22 rotating about horizontal axes may be positioned near each of the four corners of the plate 32, beneath the plate 32. Shafts 44 of the cams are mounted for free rotation on bearings and pillow blocks (not shown). The shafts 44 have timing belt pulleys 48 interconnected by a timing belt 46 fitting about timing belt pulleys 48 on each of the shafts 44 so that the cams 22 turn in unison and in the same phase, meaning that the relative position of each cam 22 is the same at all times.
A separate timing pulley 48 on one shaft 44, not visible in
At all times during operation, the height of the footplate 14 is determined by the abutment of the outer periphery of the cams 22 with cam followers 20 positioned at the lower surface of plate 32 and resting on each of the cams 22. The cam followers may include a lower wear surface 56 reducing the friction between the cams 22 and the cam followers 20 when the cams 22 are rotating. Above the wear surface 56, the cam followers 20 may be composed on an elastomeric foam 58 serving as a spring element between the plate 32 and the cams 22 providing some attenuation of the peak forces applied to the footplate 14 and high frequency vibration as may be desired.
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It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.
This application claims the benefit of U.S. provisional application 60/867,719 filed Nov. 29, 2006 hereby incorporated by reference.
Number | Date | Country | |
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60867719 | Nov 2006 | US |