CROSS-REFERENCE TO RELATED APPLICATION
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
This application is related to and claims priority to U.S. Provisional Application Serial No. 60/338,035, filed Nov. 13, 2001, entitled LEG EXTENSION EXERCISE APPARATUS, the entirety of which is incorporated herein by reference.
- FIELD OF THE INVENTION
- BACKGROUND OF THE INVENTION
The present invention relates to exercise equipment, and more particularly to a device for adjusting the range of motion of exercise machine moveable components.
Selectorized weight machines have been used in fitness clubs and athletic facilities for many years. These machines allow the user to select the weight to be lifted during a certain exercise or training protocol.
One type of a selectorized weight machine allows for variable-resistance along the range of motion of the exercise being performed. These selectorized, variable-resistance machines use a cam having a variable radius or cam profile. A tether, such as a wire cable, a chain, a belt, or the like is attached at one end to a weight stack and is attached at the other end to the cam. The changing cam profile varies the mechanical advantage in an attempt to approximate the change in anatomical mechanical advantage for the user at different points of a range of motion.
For example, when a user is at a “weak” point, where the user is unable to lift much weight, the cam profile will minimize the mechanical advantage that the weight stack has on the user. Similarly, at a user's “strong point”, the cam profile is configured to maximize the mechanical advantage that the weight stack has on the user. This process is accomplished by varying the radius of the cam profile such that in the ideal situation, the user is lifting as much weight he or she can at each point in the user's range of motion.
The “selectorized” aspect of selectorized, variable-resistance exercise machines allows the user to select a desired number of weight plates from a stack of plates, that the user wishes to engage or lift for a particular exercise. The desired number of plates is typically chosen by the user, by inserting a pin through a hole in a rod that passes through all of the plates, thus establishing plates above the pin as the weight load. Selectorized, variable-resistance weight machines are well known art.
Selectorized, variable-resistance weight machines are used in the rehabilitation field, as well as for exercise and training. For rehabilitation purposes, it is often important to limit the range of motion for the patient. For example, after certain knee injuries, it is important that the patient avoid loading muscles with weights at certain points in the range of motion. However, for other points in the range of motion, use of a weight machine may play an important part in the rehabilitation routine. Thus, selection of the correct start and stop point in the range of motion is critical to prevent injury. Sports medicine and rehabilitation physicians and physical therapists have long recognized that there are certain safe ranges of motion for rehabilitation for certain injuries, and that the use of selectorized variable-resistance exercise machines can aid in rehabilitation within the critical range limits.
However, when selecting a range of motion, the cam profile may provide inefficient, and sometime undesirable, loads for a selected range of motion. For example, during certain muscular joint rehabilitation therapies, maximum loading may be applied at inappropriate points, resulting in an ineffective therapy, or provide adverse results.
- SUMMARY OF THE INVENTION
Thus, there remains a need for a simple range-limiting device and adjustable cam device for exercise machines that can easily provide the appropriate range of motion and desired mechanical advantage configuration.
The subject invention provides a range-limiting device for use with an exercise machine. The range-limiting device allows a user to establish a range of motion, while maintaining the proper mechanical advantage provided by the cam assembly.
The range-limiting device includes a shaft having a cam and a lever disposed thereon. The range-limiting device is operatively connected to an exercise machine, wherein the lever is used for rotation of the shaft within the exercise machine and the cam is connected to a resistance mechanism. The radial orientation of the lever with respect to the cam is selectable, such that the effective radius of curvature of the cam with respect to the lever is automatically changed as the radial orientation is changed. Additionally, a plate is pivotally mounted about the shaft, where the plate limits the radial range of motion of the lever.
An exemplary exercise machine includes a support frame, where the shaft is pivotally mounted to the support frame. The cam is a start-positioning device, including an eccentric plate affixed to the shaft and an adjustable cam configured for receiving the eccentric plate and rotateably mounted about the eccentric plate. A cam plate is attached to the adjustable cam, wherein the cam plate is selectively engageable with the eccentric plate. The resistance mechanism is operably connected to the adjustable cam.
BRIEF DESCRIPTION OF THE DRAWINGS
The plate is an end-positioning device configured to be selectively engageable with the support frame, where the end-positioning device can be used to adjust the stop position of the lever. The end-positioning device and start-positioning device are used in conjunction to vary the start and stop positions of an exercise movement, while maintaining the correct mechanical advantage for the range.
A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
FIG. 1 is a perspective view of the range-limiting device of the subject invention;
FIG. 2 is a perspective view of a leg extension machine of the subject invention;
FIG. 3 is a front view of a leg extension machine of the subject invention;
FIG. 4 is a side view of a leg extension machine of the subject invention;
FIG. 5 is a left side perspective view of the start-positioning device of the subject invention;
FIG. 6 is a right side perspective view of the start-positioning device of the subject invention; and
DETAILED DESCRIPTION OF THE INVENTION
FIG. 7 is a perspective view of a leg curl machine for the subject invention.
The subject invention provides a range-limiting device for use with an exercise machine. As described herein, the range-limiting device allows a user to establish a range of motion, while maintaining a selected mechanical advantage provided by the cam assembly.
As shown in FIG. 1, the range-limiting device 10 includes a shaft 12 having a cam 16 and a lever 18 disposed thereon. The range-limiting device 10 is operatively connected to an exercise machine, where the lever 18 is used for rotation of the shaft 12 within the exercise machine and the cam 16 is connected to a resistance mechanism. The radial orientation of the lever 18 with respect to the cam 16 is selectable, such that the effective radius of curvature of the cam 16 with respect to the lever 18 is automatically changed as the radial orientation is changed. Additionally, a plate 14 is pivotally mounted about the shaft 12, where the plate 14 limits the radial range of motion of the lever 18. The radial orientations of the plate 14 and cam 16 are independently selectable, such that the reference points R1 and R2 are selectively rotateable with respect to each other. The particular orientation and spacing of the plate 14, cam 16, and lever 18 on the shaft 12 is for illustrative purposes only, and can vary depending on the structural requirements of the exercise machine in which the range-limiting device 10 is being employed.
The range-limiting device 10 can be more fully understood when described in conjunction with an exemplary exercise machine. As shown in FIG. 2, the exemplary exercise machine is a leg extension machine 20, having a support frame 22 on which a user support structure 24 is mounted. The user support structure 24 includes a seat surface 26 and an adjustable backrest 28. The adjustable backrest 28 can be adjusted in a forward and rearward direction, such that once the backrest 28 is in the appropriate position, the backrest 28 is secured in position by the backrest adjustment mechanism 30.
An input assembly 32 is positioned in front of the seat 26, and mounted to the support frame 22 for rotation about a horizontal axis A-A, as defined by the range-limiting device 10. The input assembly 32 includes a padded member 34 for a user's lower shins. A horizontal arm 38 is disposed between the vertical arm 36 and a curved offset arm 40, where the curve offset arm 40 is affixed to the range-limiting device 10, such that the padded member 34 is positioned in proximal relation to the seat 26. (See also FIG. 3) A counterweight 42 is attached to the range-limiting device 10 to balance the input assembly 32 about the horizontal axis A-A.
As shown in FIG. 3, the input assembly 32 includes an adjustable vertical arm 44, such that the padded member 34 can automatically be positioned correctly on the lower shins of a user. The adjustable vertical arm 44 is slideably mounted within a collar element 48, such that the adjustable vertical arm 44 freely floats within the collar element 48. As the user is positioned within the exercise machine, the padded member 34 is automatically positioned against the user's shins. Optionally, the adjustable vertical arm 44 can be secured in position with locking element 50. A handle element 52 is affixed to the adjustable vertical arm 44 to aid in sliding the adjustable vertical arm 44 through the collar element 42.
Referring again to FIG. 2, a weight stack brace 54 is attached to the support frame 22 by beams 50 a and 50 b and secondary support frame 58, such that the weight stack 60 is easily accessed by a user seated in the seat 26. Weight stack pulleys 62 a and 62 b are mounted to the top of the weight stack brace 54, with pulley 62 a being aligned with the range-limiting device 10 and pulley 62 b being aligned with the weight stack 60. Rails 64 are mounted vertically within the weight stack brace 54, where the individual plates of the weight stack 60 are slideably mounted to the rails 64 and provide a resistance to the exercise.
The weight stack 60 is selectively connected to one end of a cable 70 by inserting a pin in one of a plurality of holes in a lifting post 68 that passes vertically through the plates, as is well known in the art. For example, the weight stack 60 is formed by a stack of rectangular, brick-shaped plates 66. Each plate 66 further has at least one horizontal channel or hole, wherein a pin may be disposed to slideably engage any of a series of horizontal channels which are vertically oriented on the lifting post 68 in a spaced apart manner to match the vertical spacing of the stacked weight plates 66. The pin thereby engages a portion of the stack of weight plates 66, such that when vertical force is applied to the lifting post 68, the selected stack of weight plates 66 is moved upwards to create a resistance. Typically, the weight stack 60 apparatus is oriented such that the further down the pin is entered into the lifting post 68, the greater the number of plates 66 are engaged, thereby increasing the resistance of the machine.
The cable 70 extends up from the weight stack 60 and an intermediate portion of cable 70 extends over pulleys 62 a and 62 b. The second end of the cable 70 is connected to the range-limiting device 10, thereby inhibiting rotation of the range-limiting device 10
Additionally, the weight stack 60 can be connected to the range-limiting device 10 by other means known in the art, including, but not limited to, belts, cables, chains, or tethers, so as to inhibit rotation thereof.
In alternative embodiments, other mechanisms for providing resistance, such as friction fittings, springs, elastic bands, pneumatic or electromagnetic resistance, or an air resistance fan could be employed (either alone or in combination) and still practice the invention. Additionally, free weights could be operably engaged to the input assembly 32 to resist the movement.
As shown in FIG. 2, the range-limiting device 10 includes a horizontal shaft 72, defining the horizontal axis of rotation A-A, the horizontal shaft 72 being pivotally connected to the support frame 22 and the secondary support frame 58. An end-positioning device 78 and a start-positioning device 90 are affixed to the horizontal shaft 72. The end-positioning device 78 includes a detent plate 80 having a horizontal stop 81, a handle element 82, and defining a plurality adjustment holes 84. (See also FIGS. 3 and 4). The detent plate 80 is rotateably affixed about the horizontal shaft 72 and affixable to the support frame's stop arm 86 by the engagement of stop pin 88 to one of the detent plate's adjustment holes 84. The detent plate's vertical stop 81 is positioned for engagement of the curved offset arm 40, where the horizontal stop 81 limits the angle of rotation of the input assembly 32.
To adjust the input assembly's 32 stop position, the user grasps the handle element 82 and disengages the stop pin 88 from the detent plate 80, rotating, pushing or pulling, the detent plate 80, about the horizontal shaft 72, to the desired stop position. The stop pin 88 is reengaged with the detent plate 80, securing the horizontal stop 81 in the desired stop position.
The detent plate's adjustment holes 84 are equally spaced, and marker designations, such as the numbers “0” through “15,” are used to identify the stop locations. The adjustment hole 84 locations “0” represent the approximate full range of motion (as that term is understood by therapists and clinicians) for various exercise and rehabilitation protocols. Use of the “0” designation allows the therapist or clinician to quickly set the input assembly of the machine to the full range of motion.
As shown in FIGS. 5 and 6, the start-positioning device 90 is affixed to the horizontal shaft 72, and includes a cam 92, eccentric plate 94, and a cam plate 96. The cam 92 is configured to receive the eccentric plate 94, such that the eccentric plate 94 is rotateable within the cam 92. The cam plate 96 is attached to the cam 92, sealing the eccentric plate 94 within the cam 92, such that the cam 92 and cam plate 96 are rotateable about the eccentric plate 94. The eccentric plate 94 includes a cam pin 100 for engaging the cam plate's adjustment holes 98. The eccentric plate 94 is attached to the horizontal shaft's offset mounting arm 104, such the axis of rotation of the eccentric plate 94 is offset from the eccentric plate's central axis.
The cam 92 and cam plate 96 have a variable radius profile which changes the mechanical advantage over the range of motion. The shape of the cam 92 and cam plate 96 attempt to match the change in anatomical mechanical advantage at each point in the range of motion. The cam's 92 profile depends upon the type of exercise or rehabilitation protocol contemplated (e.g., leg extension, leg curl, arm curl, shoulder press, etc.) The manner in which the cam profile is established is well known to those skilled in the art.
The inputs assembly's 32 start position is adjusted by disengaging the input assembly 32 from the cam 92 and rotating, pushing or pulling, the input assembly 32 to the desired start position and reengaging the cam 92. To disengage the input assembly 32 from the cam 92 the eccentric plate's cam pin 100 is disengaged from the cam plate 96, allowing eccentric plate 94 to rotate within the cam 92 and cam plate 96. The input assembly 32 is secured in the desired start position by the cam pin 100 reengaging the cam plate 96, securing the eccentric plate 94 to the cam 92 and cam plate 96.
As noted above, the eccentric plate 94 is attached to the horizontal shaft's offset mounting arm 104, such the axis of rotation of the eccentric plate 94, is offset from the eccentric plate's central axis. Accordingly, as the eccentric plate 94 rotates within the cam 92 the radial positioning of the cam 92 about the horizontal shaft 72 is changed, changing the effective radius of curvature of the cam 92 with respect to the input assembly 32. The automatic change in the effective radius of curvature of the cam 92 provides an automatic change in the mechanical advantage over the adjusted range of motion, thus providing the correct anatomical mechanical advantage for the adjusted range of motion.
When the cam 92 is disengaged from the eccentric plate 94, the cam 92 is free to rotate in response to the tension in the cable 70. As shown in FIG. 6, the rotation of the cam 92 is limited by the cam stop 108 affixed to the secondary support frame 58 and the cam follower 106 attached to the cam plate 96, where the cam follower 106 engages the cam stop 108, preventing the cam 92 from rotating in response to the tension on the cable.
The cam plate's adjustment hole 98 locations are equally spaced, and marker designations, such as the numbers “0” through “15,” are used to identify the locations. The adjustment hole 98 locations “0” represent the approximate anatomical zero point (as that term is understood by therapists and clinicians) for various exercise and rehabilitation protocols. The cam plate's adjustment holes' 100 numbers enable the therapist or clinician to quickly set the input assembly 32 to the anatomical zero position.
In an exemplary method of use, the end-positioning device 78 and the start-positioning device 90 are used in conjunction to adjust the exercise start and stop positions. Initially, the user adjusts the start position as noted above. In doing so, the effective radius of curvature of the cam 92 is changed, providing the appropriated mechanical advantage for the new start position. The user can then adjust the stop position as noted above, thereby provided a limited range of motion for the exercise.
Referring now to FIG. 7, the present invention is shown in the context of a leg curl machine 110. In the leg curl machine 110, an input assembly 112 is provided with two spaced pads for receiving a portion of the legs below the knees. The upper pad 114 engages the top of the legs just above the knees while the lower pad 116 engages the back of the legs just above the ankle area, wherein the lower pad 116 is mounted for rotation about a horizontal axis as defined by the range-limiting device 10. To perform the exercise, the user places pressure on the lower pad 116 with his legs to rotate the movement arm about the movement arm axis during which time the upper pad 114 serves to maintain the proper position of the legs with the knees generally aligned with the pivotal axis of the movement arm.
The above-described exercise machines are only exemplary embodiments and should not be considered limiting to the types of exercise machines the range-limiting device 10 can be incorporated into. For example, the range-limiting device 10 can be used in a variety of push or pull exercise machines, including but not limited to, chest press machines, rowing machines, pull-down machines, back extension machines, arm extension and curl machines.
It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention, which is limited only by the following claims.