Abstract:
An apparatus, device, and method for measuring and displaying the amount of calories expended by a person engaged in weight lifting. The apparatus senses the displacement of a weight through the use of a sensor and a computer translates that displacement into caloric expenditure. A display provides the user with a visual report of the amount of caloric expenditure as well as other fitness parameters of the workout. The cumulative amount of calories expended over a length of time may also be provided to the user. The user can control the information displayed and the operations performed through the user interface. The apparatus and device may allow for more than one user at a time. Audible signals may be generated to inform the user about different fitness parameters.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates generally to an apparatus, device, and method for measuring the amount of calories expended by a person who is performing a physical activity. More particularly, the present invention relates to an apparatus, device and method for measuring and displaying the cumulative amount of calories expended during a weight lifting activity.  
       BACKGROUND AND SUMMARY OF THE INVENTION  
       [0002]     Providing persons who engage in physical activity with information about the intensity of their workouts has become very popular. Weight lifters, like all athletes, value the ability of knowing the details about different fitness parameters, such as how much weight they are lifting, how many repetitions they have done, and the amount of power they have expended. Fitness parameters like these are important for keeping track of athletic progress and setting workout goals.  
         [0003]     The knowledge of how many calories are expended during weight lifting and exercise in general has also become increasingly popular in today&#39;s society. For many persons, particularly those engaged in physical activity for weight-loss reasons, personal fitness goals may be set in the form of calories expended. For others, calories expended may simply serve as a guideline for the proper intensity of a workout. For all persons, knowledge of the amount of calories expended allows them to keep better track of their personal performance and fitness goals, and, ultimately, to perform better.  
         [0004]     When it comes to weight lifting and weight training, knowing the amount of calories expended through lifting weights is particularly important. For persons who engage in weight lifting for weight loss purposes, the amount of calories expended during a lifting workout may be indicative of how much fat they are burning. Persons who engage in the sports of body building and body sculpting are also particularly concerned with how many calories they are expending. Body builders and body sculptors strive to have muscular bodies and very little body fat. The less fat on a person&#39;s body, the more “sculpted” that person&#39;s body looks. Since the burning of fat is directly related to caloric expenditure, body builders and body sculptors also place a high value on having accurate knowledge of the amount of calories expended while lifting weights.  
         [0005]     Many cardiovascular exercise machines, such as elliptical trainers and treadmills, are provided with electronic monitoring devices that measure and display the amount of calories expended by the user during their use of a particular machine. However, it is much more difficult for a person engaged in weight lifting to gain even a somewhat accurate knowledge of how many calories they have expended by lifting weights. Weights do not contain electronic devices that monitor usage. Since weight lifting does not typically involve continuous activity, like most cardiovascular machines, it is difficult for a lifter to use a “rule of thumb” method and apply an average rate of caloric expenditure to their workout time to determine their caloric expenditure. Furthermore, the inherent nature of weight lifting is the ability of weights of different measure to be transferred from type of equipment to another, and placed in various combinations with each other. An example would be the ability of two 10 lb free weights to be placed on a leg press by themselves or on a barbell with two 50 lb free weights. This interchangeable nature of weights and weight lifting equipment makes it even more difficult for a weight lifter to determine their caloric expenditure. The speed with which a lifter lifts a weight affects the amount of calories burned. Depending on the lifter, this speed may vary greatly. Another factor that makes it difficult to determine caloric expenditure is that the distance a weight is lifted varies greatly depending on the lifter, the amount of weight they are lifting, the type of exercise they are engaging in and personal lifting style. For this reason the only way caloric expenditure can be accurately assessed is if it is calculated based on the distance each weight is lifted each time. This of course is a difficult and time-consuming task for any weight lifter to do. Further compounded with the fact that during a typical weight workout a lifter will use several different types of machines with different amounts of weight, the task of calculating cumulative caloric expenditure becomes virtually impossible.  
         [0006]     It is therefore desirable to have an apparatus which can measure the amount of calories expended by a lifter in displacing a weight. It is also desirable to have an apparatus which can measure the cumulative amount of calories expended during a lifting workout involving different weight exercises with various pieces of weight equipment.  
         [0007]     The present invention is claimed as an apparatus, device, and method for measuring the amount of calories expended by a person while lifting a weight. The apparatus of the present invention is comprised of a sensor that detects the relative displacement of the weight being lifted, a computer that calculates the amount of calories expended in lifting the weight, and a display that allows the user to see the amount of calories expended. The present invention is also the device that computes and displays the amount of caloric expenditure to a user. The method of determining caloric expenditure during weight lifting through the use of a sensor, computer, and display are also claimed as the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     A better understanding of the present invention will be obtained when reference is made to the accompanying drawings, wherein identical parts are identified by identical reference numerals, and wherein:  
         [0009]      FIG. 1  is a schematic illustration of the various components of an embodiment of the present invention as associated with a free weight;  
         [0010]      FIG. 2  is a schematic illustration of a second embodiment of the present invention as associated with a dumbbell;  
         [0011]      FIG. 3  is a schematic illustration of a third embodiment of the present invention as associated with a barbell and squat rack;  
         [0012]      FIG. 4  is a schematic illustration of a fourth embodiment of the present invention as associated with a home gym;  
         [0013]     FIGS.  5  is a front perspective view of an embodiment of the string sensor of the present invention;  
         [0014]      FIG. 6  is a right perspective view of an embodiment of the potentiometric mechanism and infrared system removed from the string sensor of the present invention;  
         [0015]      FIG. 7  is a left perspective view of an embodiment of the potentiometric mechanism and infrared system removed from the string sensor of the present invention;  
         [0016]      FIG. 8  is a front elevational view of an embodiment of the display console of the present invention;  
         [0017]      FIG. 9  is a rear elevational view of an embodiment of the display console of the present invention; and  
         [0018]      FIG. 10  is a block diagram illustrating the flow of information within the apparatus of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0019]      FIG. 1  illustrates an exemplary embodiment of the apparatus of the present invention. In the example illustrated, the apparatus is associated with a free weight  100  that may be lifted by a user. The apparatus includes a string sensor  10 , which contains means for sensing and communicating the displacement of a free weight  100  relative to the sensor  10 . The string sensor  10  is contained within a sensor housing  12 . In a preferred embodiment the sensor housing  12  is made of plastic, although in other embodiments other materials may be used. In many embodiments the components of the string sensor  10  will be sized so that the entire string sensor  10  and sensor housing  12  is portable and can easily be moved to different pieces of weight equipment by a user.  
         [0020]     In the illustrated embodiment of  FIG. 1  the string sensor  10  is physically connected to the free weight  100  by a string  14  that is attached to the free weight  100  by an attaching means  16 . In the illustrated embodiment of  FIG. 1  the attaching means  16  is a hook and loop fastener, such as commercially available VELCRO. However, in other embodiments of the present invention the attaching means  16  may be of a different form, including hooks, adhesives, magnets, and strappings made of various materials. In the exemplary embodiment of  FIG. 1  the string  14  is attached to the free weight  100  through the bar  110 . However, depending on the type of weight being lifted and the preference of the user, in other embodiments of the present invention the string  14  may be attached to any part of a weight or connected part that moves when the weight is lifted. Examples include the weight itself, weight handles, pins, weight plates, and weight bars.  
         [0021]     A computer  18  receives signals from the string sensor  10  and performs calculations of various fitness parameters based on those signals. As shown in  FIG. 1 , the string sensor  10  and computer  18  may be interconnected through a cable  20  that allows the string sensor  10  to communicate signals to the computer  18 , and may also provide power to the string sensor  10 . The cable  20  may also serve as a power source for the string sensor  10 . In a preferred embodiment of the invention the cable  20  is sufficiently long so that the string sensor  10  may be placed at a distance away from the computer  18 . However, in other embodiments of the present invention the computer  16  and the sensor  10  may be connected by a much shorter cable, or connected together in one device. In some embodiments of the present invention the string sensor  10  and computer  18  may not be attached by a cable  18 . In these embodiments, the computer  18  and string sensor  10  may communicate by other means. Examples of wireless ways in which the computer  18  and string sensor  10  may communicate include infrared or wireless technology, such as BLUETOOTH wireless technology which is commercially available from BLUETOOTH SIG, INC.  
         [0022]     Information processed by the computer  18  of the present invention may be communicated to a user through a display  22  that is part of a larger display console  24 . In the preferred embodiment of the present invention, and as shown in  FIG. 1 , both the computer  18  and display  22  are contained in the display console  24 . However, in other embodiments of the present invention the computer  18  may be located outside of the display console  24 . For example, the computer  18  may be contained within the sensor housing  12  along with the string sensor  10 , and may communicate to the display console  24  through a cable or wireless means. In other embodiments of the present invention, the computer  18  is contained within the sensor housing  12  and the display  22  is integrated into the outside of the sensor housing  12 . In this embodiment of the present invention, the invention consists of one portable unit, and there is no separate display console  24 .  
         [0023]     In the preferred embodiment of the present invention the display console  24  is portable and can be easily transported by the user. As shown in the illustrative embodiment of  FIG. 1 , the display console  24  may be placed on a stand  120  or placed in another location in the vicinity of the user as desired. In a preferred embodiment of the present invention the display console  24  is located near the user and is positioned so that the display  22  may be easily seen by the user. In some embodiments of the present invention the display console  24  may be mounted on a weight, weight machine, or other structure in the vicinity of the user so that it may be easily viewed by the user while they lift the weight. This may be done by placing the display console  24  in a console holder  26  located on a machine. In other embodiments of the present invention the display console  24  may be mounted through the use of straps, magnets, hooks, hook and loop fasteners, adhesives, or other mounting means.  
         [0024]      FIG. 2  illustrates an embodiment of the present invention as associated with a dumbbell and a weight bench. The string sensor  10  is located on the floor at the base of the weight bench  140 . The attaching means  16  for the string is a magnet that has been placed onto the side of the dumbbell  130 .  
         [0025]     In the schematic illustration of  FIG. 3  the present invention is associated with a barbell  150  and a squat rack  160 . The string sensor  10  is located at the based of the squat rack  160  and the string  14  is attached to the bar of the barbell  160 . The attaching means  16  is a magnet that has been placed onto the side of the barbell  150 . The display console  24  is mounted to the side of the squat rack  160 .  
         [0026]     In the schematic illustration of  FIG. 4  the present invention is associated with a home gym  170 . The string sensor  10  is located at the base of the home gym  170  and the display console  24  is located in a console holder  26  which as been attached to the home gym  170 . The attaching means  16  of the string is a magnet. In the illustrative embodiments of  FIG. 4  there is no cable  20  connecting the display console  24  to the string sensor  10 .  
         [0027]     The present invention can be associated with various types of exercise equipment other than those illustrated in the exemplary embodiments of  FIGS. 1-4 . The present invention can be used in association with virtually any type of weight equipment including various home gyms, flex-rod machines weight bars, dumbbells, circuit machines, hydraulic machines, and plate loaded machines.  
         [0028]      FIG. 5  is a front perspective view of the string sensor  10  as shown in  FIG. 1 . In a preferred embodiment, the string sensor  10  includes a potentiometric mechanism  28  and an infrared sensor system  30 , which are contained inside the sensor housing  12  and therefore not depicted in  FIG. 5 . Although in a preferred embodiment the sensor housing  12  has a cylindrical shape similar to the shape of the potentiometric mechanism  28  contained within, in other embodiments of the present invention the sensor housing  12  may have a variety of shapes. For example, the sensor housing may be shaped like a box.  
         [0029]     As shown in the perspective view of  FIG. 6 , in a preferred embodiment of the present invention the potentiometric mechanism  28  is comprised of a reel  32  which is supported on a shaft  34  by bearing mechanisms  36 . The shaft  34  is rotatably supported by the sensor housing. As shown in  FIG. 5  the shaft  34  may extend through the side of the sensor housing  12 . However, in other embodiments the shaft may be supported by other types of support elements. As shown in  FIGS. 5 and 6 , the string  14  of the string sensor  10  extends through an opening  38  in the sensor housing  12  and is wound around the reel  32 . When a sufficient amount of tension is applied to the outer end  40  of the string  14 , the reel  32  rotates and the string  14  is unwound from the reel  32 . In a preferred embodiment of the present invention, the inner end of the string  14  is attached to the reel  32  to prevent the complete removal of the string  14  from the reel  32 . In a preferred embodiment of the present invention, the string  14  is no more than seven feet long and less than a half inch in diameter. However, in other embodiments of the present invention the string  14  may be of a longer length or larger thickness. In a preferred embodiment of the present invention the string  14  is also made out of a material that can support high tension such as multi-strain steel. However, in other embodiments different materials may be used. In some embodiments of the present invention the potentiometric mechanism  28  may include a ratchet wheel  44  and corresponding pawl  46  that ensure that the reel  32  rotates in only one direction while a weight is being lifted.  
         [0030]     In a preferred embodiment of the present invention, and as shown in  FIG. 6 , the reel  32  is spring loaded  48  to allow for automatic retraction. In other embodiments of the present invention different mechanisms may be used for automatic retraction. Automatic retraction allows the present invention to be utilized during weight exercises that involve repetitive motions. An example of this would be the repetitive lifting and lowering of a dumbbell by a user doing an arm curl, the apparatus of which is shown in  FIG. 1 . When the dumbbell  130  is raised, and moves in a direction away from the string sensor  10 , tension is applied on the string  14  which causes the reel  32  to rotate and unwind the string  14 . The unwinding of the string  14  continues until the user has raised the dumbbell  130  to its farthest position relative to the string sensor  10 . At this point, the amount of tension on the reel  32  is insufficient to rotate the reel  32  any further, but strong enough to prevent the string  14  from being retracted. When the dumbbell  130  is lowered, and the tension on the string  14  is relieved, the reel  32  retracts the string  14 . In doing so, it reduces the slack in the string  14 . The automatic retraction continues until the dumbbell  130  reaches its closest point relative to the string sensor  10 . In a preferred embodiment of the present invention the automatic retraction of the string  14  will cease once the reel  32  has spooled a predetermined amount of string  14 . This prevents the string  14  from being completely retracted into the sensor housing  12  and completely spooled around the reel  28 . It is also preferable that a certain length of string  14  remain outside of the sensor housing  12  so that it may be easily accessed by the user.  
         [0031]     As shown in the perspective view of  FIG. 7 , the infrared sensor system  30  of the string sensor  10  is comprised of an encoding disk  50 , an infrared emitter  52 , an infrared sensor  54  that has at least one receiver, and a substrate circuit  56 . The encoding disk  50  is attached to one side of the reel  32  in such a way that it rotates at the same speed as the reel  28 . The substrate circuit  56  is located over the encoding disk  50  in such a way that the infrared emitter  52  and sensor  54 , both of which are attached to the substrate circuit  56  are located on either side of the encoding disk  50 . In a preferable embodiment of the present invention, the substrate circuit  56  is a printed circuit board (PCB). However, in other embodiments of the present invention different types of circuits may be used. As shown in  FIG. 7 , the infrared sensor  54  is located in a position directly across the encoding disk  50  from the infrared emitter  42 . In a preferred embodiment, the infrared sensor  44  and emitter  42  should be positioned such that when the encoding disk  50  is rotating the infrared sensor  54  can receive the corresponding pulses of infrared light from the infrared emitter  52 . The substrate circuit  56  can then translate these pulses into electronic signals which are sent to the computer  18  to be used for determining the relative displacement of the weight being lifted to the string sensor and the related fitness parameters. In a preferred embodiment of the present invention, the infrared sensor  54  has two receivers that produce two independent signals. Depending on which signal is received first by the computer, the computer is able to determine whether the reel is rotating in a clockwise or counterclockwise fashion. The signals from the infrared sensor are communicated to the computer via a Schmidt circuit, which translates the original signals into square wave signals which may be read by the computer  18 . However, in other exemplary embodiments of the present invention different forms of circuitry may be used.  
         [0032]     In an exemplary embodiment of the present invention, the string sensor may include an accelerometer instead of a potentiometric mechanism  28  and infrared sensor system  30 . In this embodiment, the sensor housing, containing the accelerometer, may be attached to the weight. The accelerometer may communicate data to the computer  18  regarding the movement of the weight while it is being lifted. The computer  18  may then use the data from the accelerometer to calculate the displacement of the weight and the related fitness parameters, such as caloric expenditure.  
         [0033]     In a preferred embodiment of the present invention, and as shown in  FIGS. 1-4 , the string sensor  10  is located below the weight that is being lifted by the user, such as on the ground or otherwise at the base of a piece of weight equipment. However, in other embodiments of the present invention the string sensor  10  may be located in a different direction relative to the weight being lifted. In some exemplary embodiments the string sensor  10  may be mounted to a piece of weight equipment or other structure. The mounting means for attaching the sensor  10  may include magnets, hook and loop fasteners, adhesives, strappings, hooks, clips, or other means. It is preferable that the sensor  10  be attached to a structure that will remain stationary while the user is lifting the weight. This ensures that the sensor  10  will accurately detect the relative displacement of the weight being lifted, and that the invention as a whole can provide the user with accurate information about their weight lifting. Both the squat rack  160  in  FIG. 3  and the home gym in  FIG. 4  are examples of structures that the string sensor  10  may be attached to.  
         [0034]      FIG. 8  is a front elevational view of an embodiment of the display console  24  of the present invention. As shown in  FIG. 8 , the display  22  is a liquid crystal display (LCD) panel. -However, in other embodiments the display  22  may be a light emitting diode (LED) display, fluorescent panel, or other form of display. In this embodiment several parameters of the user&#39;s workout are visually displayed. One of these parameters is the amount of calories expended  58 . In a preferred embodiment of the present invention the display  22  will provide the user with the cumulative amount of calories burned during a workout, and not just those expended in lifting a certain weight one time. Other parameters of the user&#39;s workout may also be shown on the display include the amount of weight being lifted  60 , the power necessary for lifting a weight a certain distance  62 , the power factor of the lift  64 , the amount of time the user has been lifting weights  66 , or the body weight of the user  68 . The exemplary values of the parameters shown in  FIG. 8  were calculated for a person weighing approximately 190 lbs who lifts a 200 lb one time. Some embodiments of the present invention may visually display information for more than one user at a time.  
         [0035]     As shown in  FIG. 8 , in a preferred embodiment of the present invention the display console  24  may contain a user interface  70 . The user interface  70  allows the user to interact with and control the calculations of the computer  18 . The user interface  70  may include keys  72  that allow the user to control the calculations of the computer  18 , the display of information, and allow different users of the display console to obtain their personal information. For example, the keys  72  may allow a user to input the amount of weight they are lifting, or allow the user to turn the display console  24  on and off. Other embodiments of the present invention may have different types of user interfaces  70  that allow the user to interact with the apparatus through other means. Examples include touch screens, buttons, and keypads.  
         [0036]      FIG. 9  is a rear perspective view of the display console as embodied in  FIG. 8 . As shown in  FIG. 9 , the user interface includes an audio system for generating audible signals. The display console  24  has at least one speaker  74  for providing audible signals to the user, and the computer  18  contains the necessary electronic components for creating audio signals. Although the speaker  74  is located on the backside of the display console  24  in the embodiment of  FIG. 7 , in other embodiments the speaker may be located elsewhere on the display console  24 . Audible signals allow a user to obtain information about their weight lifting parameters without having to look directly at the display console  24 . For example, the computer  18  may calculate the proper amount of rest time between repetitions and communicate these rest times to the user using audible signals. This may provide the user with more freedom in movement, allow them to focus more on their weight lifting, and be more conducive overall to the setting and atmosphere of weight lifting.  
         [0037]      FIG. 10  is a block diagram of an embodiment of the communication of information involved in the present invention. As depicted, the computer  18  receives information from the string sensor  10  regarding the displacement of a particular weight relative to the string sensor  10 . The computer  18  calculates several fitness parameters based that information as well as information which may be entered by the user through the user interface  70 . For each weight that is lifted in association with the present invention, the computer  18  needs to know how large the weight is in order to calculate many of the fitness parameters. In a preferred embodiment of the present invention, the user will enter the amount of weight being lifted through the user interface  70 . However, it is also possible that the computer will receive information about the amount of weight being lifted through other means. For example, in one embodiments of the present invention, as associated with weight equipment that has a weight stack, the string sensor  10  will be able to determine how much weigh is being lifted, depending on the amount of string  14  located outside of the sensor housing  12  at the beginning of the lift. For example, if each weight on the stack is 2 inches thick and weighs 10 lbs, when the string sensor is associated with a 60 lb lift from the stack, approximately 6 inches of string will be outside the sensor housing  12  at the beginning of the lift. As long as the computer  18  is given information on the amount of weight in one unit of weight on the stack, signals from the string sensor  10  can be used to determine changes in the amount of weight being lifted.  
         [0038]     The parameters which may be calculated by the computer  16  include the amount of calories expended and the power generated in displacing the weight. Power generated and calories expended are related by the formula: 
 
 K   cal   =W× 0.011833 
 
 wherein K cal =kilocalories expended and W=power in watts. Power is determined from the equation: 
 
 W=F ×((1.35)/((12/ D )× t )) 
 
 where F=the weight lifted in pounds, D=the distance the weight is lifted in inches, and t=the amount of time it takes to lift the weight in seconds. An exemplary embodiment of the present invention will also calculate the “Power Factor” of the lift. This is a measurement of the amount of power generated in a lift per body weight. The formula is: 
 
 PF=W/B  
 
 where W=power in watts and B is the body weight of the lifter in pounds. 
 
         [0039]     Furthermore, some embodiments of the present invention may calculate additional fitness parameters for the user, including the number of repetitions incurred by the user during the lifting of a specific weight or the rest time between instances of lifting a weight.  
         [0040]     In an exemplary embodiment of the present invention, the computer  18  may store information about each instance of a displacement of a weight during a particular time period. For example, the computer  18  may store information during the course of a user&#39;s entire weight lifting workout. The computer  18  may then access these stored values in order to calculate cumulative fitness parameters, such as the cumulative amount of calories burned, or the cumulative amount of power generated over a specified time. The computer  18  may also calculate averages of fitness parameters over a particular time period. These may include the average amount of calories expended per minute during a workout, or the average amount of power expended. In some embodiments of the present invention the computer  18  may retrieve information pertaining to past workouts, and use it to provide the user with comparative data regarding past and current workouts. An example would be providing the user with a bar graph showing the user&#39;s caloric expenditure per workout over the past month. All fitness parameters and information calculated by the computer  18  may be communicated to the user via the display  22  and audio systems  76  of the display console  24 . In some embodiments of the present invention the computer  18  may calculate, store, and retrieve information for more than one user.  
         [0041]     In an exemplary embodiment of the present invention the computer may also be connected to a printer  78 . The printer  78  may provide the user with a paper copy of the information that has been calculated by the computer  18 . For example, the printer  78  may print out summaries of different fitness parameters of the user&#39;s workout, or may print out what information is shown on the display  22 . The user may control what information is printed through the user interface  60 .  
         [0042]     In an exemplary embodiment of the present invention the computer  18  may also be able to save and retrieve information from a portable storage device  80 . This may allow the user to upload saved data from the present invention onto a different computer, such as a home computer. In addition, different users who wish to share the same display console  24  can access their past fitness parameter data by uploading the data from the portable storage device  80  onto the display console  24 . Examples of portable storage devices include floppy disks, hard disks, cds, USB memory sticks, storage disk for the user. In the illustrated exemplary embodiment of  FIG. 9 , a USB port located on the back of the display console  24  allows a user to upload information onto a USB memory stick.  
         [0043]     In an exemplary embodiment of the present invention, the apparatus may consist of more than one string sensor, and one central computer  18  that is separate from and communicates with more than one display console  24  over a network. In this embodiment the string sensors may be integrated into the weight equipment. The central computer  18  has the ability to receive signals from each string sensor  10  when the respective weights are being lifted, and can relay that information to the display console  24  being used by the user of that particular weight.  
         [0044]     In a preferred embodiment of the present invention, the string sensor  10  is powered through the cable  20 , which receives power from batteries contained in the display console  24 . In a preferred embodiment the batteries are rechargeable and are charged by a detachable AC/DC power cord  84  that can be plugged into the display console  24  as necessary. However, in other embodiments of the present Invention the apparatus may be powered by other means. For example, in embodiments where the string sensor  10  and display console are not connected by a cable  20 , the string sensor  10  may directly receive power through an AC/DC power cord  84 . In other embodiments of the present invention different parts of the apparatus may receive power through different combinations of batteries and power cords.  
         [0045]     The preferred embodiments herein disclosed are not intended to be exhaustive or to unnecessarily limit the scope of the invention. The preferred embodiments were chosen and described in order to explain the principles of the present invention so that others skilled in the art may practice the invention. Having shown and described preferred embodiments of the present invention, those skilled in the art will realize that many variations and modifications may be made to affect the described invention. Many of those variations and modifications will provide the same result and fall within the spirit of the claimed invention. It is the intention, therefore, to limit the invention only as indicated by the scope of the claims.