The present invention generally relates to the field of exercise machines, and more particularly to resistance and weight training exercise machines and related methods.
A traditional weight machine generally includes a stack of weight blocks arranged in a vertical array and an engagement member to select a particular block lifts that block and all upper blocks. The use of a weight stack provides a relatively easy method to change the resistance for a particular exercise or a particular subject. However, the weight stack produces high frictional losses due to the required tracks and guide rods on either side of the blocks to control the movement of the selected blocks and ensure they do not become misaligned or disengaged. Most of the effort in friction reduction involves using lower friction bearing materials on the weight blocks starting with metal plane bearing material, plastic bearing material up to the low friction linear ball bearings. However, the high expense of linear ball bearings used for each weight block has resulted in few manufacturers migrating from the higher friction plane bearing methods. The present invention is directed to a need in the art to develop a weight resistance source for weight training machines providing reduced frictional losses while minimizing the associated expense.
In keeping with the teachings of the present invention, a weight training apparatus may comprise a track rotatably connected to a frame for rotation of the track about a first axis. A resistance block may be carried by the track at a preselected position for providing a preselected torque thereto. A movement arm may be pivotally connected to the frame for rotation about a second axis. The movement arm includes a user engagement portion for applying a resistive force to the movement arm. One embodiment may include a resistance arm for use as the user engagement portion. The resistance block and the track may be defined as forming a resistance block assembly having a center of gravity. A coupling between the movement arm and the assembly causes a rotating of the track about the first axis in response to a rotation of the movement arm about the second axis, wherein an angular movement of the center of gravity of the resistance block assembly through a first arc length results from an angular movement of the user engagement portion through a second arc length, and wherein the second arc length is greater than the first arc length for all rotations of the movement arm and the track. The center of gravity of the assembly thus desirably moves more slowly than the user contact portion.
Embodiments of the invention may include a keeper securing the resistance block to the track at the preselected position, wherein the keeper comprises drive means operable with the resistance block for movement thereof. The resistance block may be moved from one preselected position to another for one fixed weight training to another, or may be moved within a given weight training. By way of example the resistance felt by a user operating the movement arm may react to a first torque provided by the resistance block assembly during an eccentric movement and to yet another during a concentric movement. The drive means may comprise a threaded shaft, and wherein rotation of the shaft results in a linear movement of the resistance block along the track. Yet further, the drive means may comprise a crank for manually rotating the shaft or a drive motor for rotating the shaft.
In one embodiment, the resistance block is carried by the track so as to distribute its weight such that a center of gravity of the resistance block is generally aligned with a longitudinal axis of movement of the resistance block along the track. Embodiments may also include the resistance block having a plurality of weight blocks. The resistance block may be moved to locations along the track so as to provide positive and negative torque to the track. Yet further, a wheel assembly may be employed with the resistance block and the track for ease in sliding the resistance along the track from position to alternate position.
For embodiments of the invention, the coupling may comprises resistance modulating means for modifying a resistance felt by the resistance arm at various locations within the second arc length for a fixed preselected position of the resistance block on the track. By way of example, the resistance modulating means may comprise a cam, a rod, a belt, or a combination thereof. The fixed link may comprise a lift bar fixedly attached to the track, wherein the lift bar includes opposing plates in spaced relation for permitting the resistance block to pass therebetween. The lift bar may further include a link bar providing an attachment point for the coupling. Alternatively, the fixed link may be pivotally attached to the track at a third axis.
The movement arm may further comprise adjustable means for slidable movement of the resistance arm toward and away from the second axis of rotation, thus allowing a modification to the length of the second moment arm.
A seat assembly may be connected to the frame and may comprise a base support and a back support.
Features and benefits of the present invention will become apparent as the description proceeds when taken in conjunction with the accompanying drawings and photos in which:
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and prime notation is used to indicate similar elements in alternate embodiments.
Referring initially to
With continued reference to
As illustrated herein by way of example with reference to
In one embodiment, and as illustrated with reference to
For alternate embodiments of the invention, the coupling 38 may comprise a resistance modulator 72 for modifying a resistance felt by the resistance arm 34 at various locations within the second arc length 42 for a fixed preselected position of the resistance block 20 on the track 12, or at varying locations along the track for operations where the resistance block is moving as a result of the motor drive 56 continually or intermittently relocating the resistance block during a desirable exercise. By way of example, the resistance modulator may comprise a cam 74 (as illustrated with reference to
With reference again to
As illustrated with reference again to
By way of further example, and with reference again to
With reference again to
An attachment to the track may be a flexible tensile member such the strap 88 above described or may be a chain or rigid member to transmit a force to the movement arm 28. The threaded shaft 52 secures the resistance block 20 at the preselected position 26. To adjust the position of the resistance block 20 along the track 12, the threaded shaft 52 is rotated and the resistance block 20 is moved along the side plates to a desired location.
With reference again to
The resistance modulator 72 may change the resistance so that the user is presented with enough resistance to be challenged but not enough resistive force to overcome to prevent completion of a desired exercise movement. The seated leg extension machine illustrated as the apparatus 10 may have a resistance profile that increases from the beginning of the exercise, progresses to a maximum when the knee joint forms an approximate 90 degree angle, and decreases to below the starting resistance at the end of the exercise. As above described and as illustrated by way of example with reference to
By way of example with regard to use or operation of the apparatus 10, 11, in selecting a desired level of resistance, a minimum level of resistance may be attained by positioning the resistance block 20 at the zero position, in which the center of mass of the track and resistance block generally coincides with the first fulcrum 16 (see
By way of example with regard to a weight training program, the track carrying the resistance block accepts work from the user to rotate upward in a gravitational field, increasing the potential energy of the weight provided and thus the resistance provided to the user. On the return movement or eccentric portion of an exercise, the potential energy is returned to the user who expends work to lower the weight under control. Minimal frictional loss occurs during the movement of the track during a repetition cycle, as the weight only generates friction at the first fulcrum 16, which may be anti-friction ball bearings of appropriate size, for example. Such a weight resistance structure produces noticeably less friction than multiple plane bearings sliding along twin guide rods. Moreover, the leg extension machine of apparatus 10 illustrated in
The torque that exercisers can transmit to an arm or pad of a machine varies with the movement of limb within the range of motion. The muscles that extend the leg at the knee (quadriceps) are able to produce 65% to 85% of the peak torque that occurs when the Tibia is approximately at right angles to the Femur. From this peak, the produced torque smoothly decreases to about 30% to 50% of the peak in the fully extended position. The resistance modulator 72 such as the cam and belt, cam and follower or linkage system as earlier described, may be such so as to provide a resistance to the user that matches the torque that the user can produce at a particular point in the range of motion. This means that the resistance provided by the apparatus 10, 11 is lower where the user produces less torque and is proportionally greater where the user is strongest. The torque that users can produce at various angles within the range of movement can be measured and averaged to come up with a machine resistance profile. These profiles vary for each muscle group and limb exercised as well as for the position of the users' body during the exercise. For instance, the torque and the range of motion of the hamstrings vary slightly when the hips and trunk are flexed or straight.
The resistance presented by a weight training machine must be less than the torque that the user can supply or the user will not be able to complete the repetition. In order to stimulate muscle growth however, the resistance should be challenging enough so that the body tends to rebuild. Ideally then, the resistance should be just slightly lower than the user's torque capacity at each angle in the range. This will ensure that the exercise can be completed through the full range of motion and the effort will be close to the maximum level that the user can apply at the strongest areas as well as the weaker angles.
One basis for designing a resistance modulation profile includes the law of conservation of energy. For weight training machines, the mechanical work input by the user equals the change in potential energy of the weight mass plus the friction plus kinetic energy. All other energy sources and sinks are neglected as inconsequential. In order for the resistance profile of the machine to be accurately presented to the user, the friction and kinetic energy component of the machine should be reduced to the greatest practical extent, as is the case from the embodiment of the invention herein described. The track and resistance block forming a resistance module based on a pivoting lever is inherently low in friction in comparison to weight stacks with guide rods, typically seen in the art. Keeping the distance traveled by the module center of mass less than the distance traveled by the engaging body part reduces the velocity of the resistance mass. The low velocity reduces kinetic energy content of the movement which is related by ½mv2. The m is mass and velocity is v. Because the friction and kinetic components of the repetition are reduced, the work added by the user more closely follows the resistance profile designed into the machine.
When the displacement of the center of mass of the resistance module over the repetition cycle is less than the resistance arm, by way of example, the velocity or acceleration is correspondingly less than that of the resistance pad and may not contribute large kinetic energy effects in addition to the inherent resistance profile. The resistance module may include the center of mass of the resistance module positioned along the side bars of the track such as at the maximum position, for example, and displacing a distance less than the resistance arm over the repetition cycle. Thus, for all resistance levels, the kinetic energy effects may be minimized. A less desirable configuration may include a small mass displacing a larger distance than the resistance arm, resulting in a higher travel velocity and high kinetic energy effects. The typical design for weight training systems have the distance traveled by the engagement pad or handle equal to or less than the distance traveled by the mass center of the resistance weight. The resistance module has the center of mass traveling less than the distance of the engagement handles and pads. Consider a distance traveled by the resistance arm or handles of an alternate apparatus, by way of example, to be Dh and the distance of travel of the weight module center of mass to be Dwt. The resistance module will follow the equation Dh/Dwt<1.
A repetition cycle may involve a concentric portion where the tension of the muscle and the direction of movement are the same, and an eccentric portion where the tension of the muscles and the direction of movement of the muscles are in opposite directions. During a biceps curl, for example, the concentric portion of the exercise may be lifting the weight and the eccentric portion may be lowering the weight.
The eccentric portion of a repetition in current weight training machines may involve less resistance due to frictional loss of the machines. However, the frictional loss of such machines may add to the resistance during the concentric portion of the repetition cycle. Thus, the frictional loss may add to the concentric resistance when lifting the weight and subtract from the eccentric resistance when lowering the weight. Thus, the eccentric portion of the repetition cycle may be less effective than the concentric portion.
The resistance module may provide a consistent level of resistance throughout the repetition cycle by supplying additional resistance during the eccentric portion to offset frictional loss. Increasing the resistance during the eccentric portion may be accomplished through moving the resistance block 20 away from the first fulcrum 16 when the user begins the lowering part of the exercise. By lengthening the distance the resistance block 20 can travel by 20%, for example, or decreasing the maximum concentric travel by 20%, for example, the muscles may encounter greater resistance in the eccentric portions of the repetition cycle. Upon the user beginning the concentric portion, the resistance block 20 may have returned to its initial position on the track 12.
The ability of the user to generate torque at a particular limb angle may be used to generate the resistance curve that is designed into the cam, lever or other resistance modulator 72 providing a modulating effect. The match between the programmed resistance curve and the user's ability to generate torque should be similar to accomplish an efficient exercise. If the match is not sufficiently similar, the user may not be able to exercise in a portion of the repetition range, nor be sufficiently challenged in a portion of the repetition range.
The resistance block 20, as above described, may be moved along the track 12 using the drive motor 56 controlled to adjust the position of the resistance block 20 to a particular position at the beginning of an exercise when a minimum amount of control is used. By increasing the amount of control, the motor may move the resistance block to the endpoints of the exercise to increase the eccentric phase of the exercise and decrease the concentric phase.
Consider a workout with increased eccentric phase resistance to include the following steps:
1. Set eccentric phase resistance level (may enter on a keypad 106 forming a portion of a controller 108, as illustrated with reference again to
2. Set concentric phase resistance level (enter on keypad)
3. Set range of motion (complete repetition with ½ concentric resistance, end points recorded)
4. Machine sets concentric value (moves weight block to position)
5. Machine signals ready to start (screen text, audio cue)
6. Start exercise
7. At the end of the range, pause under load for 2 seconds (weight moves to eccentric value)
8. Lower weight under control
9. Immediately begin to lift weight (weight moves to concentric value)
10. Repeat steps 6-9 (machine records repetition and time of exercise)
11. Exercise recording and weight changes stop when the range decreases to 80%
The eccentric and concentric resistance levels can also be set by entering either the concentric level or the eccentric level and entering the percentage increase of the eccentric over the concentric resistance levels. An increase of 2% to 5% would be equivalent to completely removing friction out of the exercise machine. In this case the addition of machine friction to the concentric movement and the subtraction of the machine friction from the eccentric movement would be offset exactly by the additional resistance for the eccentric movement. The eccentric strength level is commonly thought to be 40% greater than the concentric strength level. This could be the default setting for the machine when using the increased eccentric mode. Otherwise the percentage of increase would be entered by the user or trainer.
Consider a maximum effort workout to comprise the following steps:
1. Set range of motion with moderate speed full repetition (speed 3-8 second lift, 2-5 second pause-6-10 second lower and end points recorded)
2. Set concentric resistance to 1 RM or slightly lower (1 Repetition maximum or 5% to 10% lower)
3. Machine sets concentric value (moves weight block to position)
4. Machine signals ready to start (screen text, audio cue)
5. Start exercise
6. Machine records complete repetitions that are full range within 80%-90%.
7. Machine lowers weight until the range is within 80%-90% of the original
8. When concentric values are lower than the 1 RM by 20%40%, the increased eccentric resistance workout steps begin steps 8-9-10
9. When either concentric or eccentric phases are below 80%-90% of the range, the weight lowers until the range is restored.
10. Machine records full range repetitions and time of the exercise
11. Workout ends at selected repetition, time or percentage of starting weight.
An additional variation of a standard workout keeps the same resistance setting for the concentric and eccentric phases. This variation is similar to having a trainer or spotter assist the exerciser complete the last several repetitions.
A concentric workout with maximum effort finish may comprise:
1. Set concentric phase resistance level
2. Set range of motion
3. Machine sets concentric value (moves weight block to position)
4. Machine signals ready to start (screen text, audio cue)
5. Start exercise
6. Pause at the end of the range
7. Lower weight under control
8. Immediately begin to lift weight
9. Repeat steps 6-9 (machine records repetition and time of exercise)
10. When range of motion falls below 80%-90% of the recorder ROM, the weight reduces until the ROM is restored.
11. Reduction of weight continues for either a set number of additional repetitions or until the weight is a certain percentage of the original weight setting.
The increased eccentric phase workout can have the maximum effort finish as well. Consider the following.
1. Set eccentric phase resistance level
2. Set concentric phase resistance level
3. Set range of motion
4. Machine sets concentric value (moves weight block to position)
5. Machine signals ready to start (screen text, audio cue)
6. Start exercise
7. At the end of the range, pause under load for 2 seconds (weight moves to eccentric value)
8. Lower weight under control
9. Immediately begin to lift weight (weight moves to concentric value)
10. Repeat steps 6-9 (machine records repetition and time of exercise)
11. When either concentric or eccentric phases are below 80%-90% of the range, the weight lowers until the range is restored
12. Reduction of weight continues for either a set number of additional repetitions or until the weight is a certain percentage of the original weight setting
Yet further, the controller 108 may include a full servo feedback system may be used, for example, to control the position and velocity of the resistance block and enable the machine to superimpose a correction to the “hardwired” resistance curve that would enable an ideal match between the subject's ability and the machine's resistance. Such a hybrid electro-mechanical machine's primary resistance may be supplied by the resistance block being lifted and lowered while the servo-mechanics may shape the resistance to the user by making small change to the design in average resistance provided by the cam or levers. This system may differ from pure electronic exercise devices that use servo motors for resistance. The systems for electronic resistance machines may be very fast, accurate and generate great amounts of torque.
In an exemplary embodiment, a hybrid electro-mechanical system may only need the power and control to move a 100-400 pound mass along a low friction linear guide rod rather than having to generate up to 1000 to 1500 ft-lb of work in less than 90 degrees of movement arm rotation.
Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings and photos. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and alternate embodiments are intended to be included within the scope of the claims supported by this specification.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/826,395 filed Sep. 21, 2006, the disclosure of which is hereby incorporated herein in its entirety by reference.
Number | Date | Country | |
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60826395 | Sep 2006 | US |