Abstract:
The present invention utilizes a split hub assembly that provides the user two modes of operation, unipedal or bipedal. Unipedal mode is when each crank is functioning independent of the other thus forcing the user to work each leg differently yet simultaneously. Bipedal simulates the normal operation of a bicycle. In the preferred embodiment, each side of the invention (left and right side for left and right legs) has its own drive system. The split hub assembly is housed between each drive system, and by using an actuator, the drive systems can be connected to provide bipedal operation, or disconnected to provide unipedal operation. This allows each side, in unipedal mode, to vary its resistance without affecting the other side in order for a patient to exercise both legs separately and favor one with a different resistance to account for an injury or recovery from surgery. The friction brakes for each drive system are controlled by a microprocessor that turns the motors in the required direction for either increasing or decreasing the tension on the brake belt. The microprocessor monitors power and performance and regulates the resistance levels to deliver either isotonic or isokinetic resistance. The resistance in bipedal mode is varied in the same manner, but the resistance is equal on each leg.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to bicycles for exercise and/or therapeutic purposes. 
     2. Description of the Related Art 
     The bicycle has been tremendously successful not only as a form of transportation, but for exercise purposes as well. The term bicycle used in this context includes road bikes as well as stationary bikes. In the marketplace, road bikes and stationary bikes have proven to be extremely successful. Literally tens of millions of both road bikes and stationary bikes are used on a regular basis which demonstrates not only the popularity of the bicycle as a machine per se, but also the general interest of the population in using machines for exercise, conditioning and therapeutic purposes. 
     In this regard, the proliferation and success of a myriad of exercise machines has been extensive over the last two decades. This proliferation coincides with an increased awareness in the community of health consciousness, physical conditioning, and a sense of well-being from exercise. 
     The road bike and stationary bike, however, have remained a very popular alternative for exercise and rehabilitation. There have been no significant technological or structural changes to the bicycle over the past decades. Inherent in the concept of the bicycle as a machine is the creation of efficiency, i.e., to reduce the workload required to perform a certain function. The stationary bicycle continues to use a single drive sprocket (may or may not include a flywheel) joined by a single axle having two cranks coupled 180 degrees out of phase with each other while utilizing various types of resistance. The resistance and work output are related to the amount of resistance applied to the cranks. Of great interest to the exercise community, both for exercise and therapeutic purposes, is the ability to maximize work output per unit time. An example of an attempt to expand work output as well as expanding the physical demands on an increased number of muscles can be seen in an aerodyme bike. The aerodyme bike requires pedaling while simultaneously exercising the upper body with the use of crank arms. 
     In reference to the muscles worked during bicycling, the extensor muscles, i.e., the quadriceps and hip extensors are essentially emphasized. During pedaling, most of the work output is created on the downstroke with momentum while the opposite pedal takes the leg through the upstroke with a much reduced work demand. Experienced professional riders learn to push and pull to maximize their workload during short bursts, but even in this regard, the upstroke pedal is still assisted by the opposite downstroke pedal. 
     Herein is where the deficiency lies. When someone with an injury in one leg wants to use a road bike or a stationary bike, one leg is dependent on the other because normal bicycles are bipedal. In other words, the injured leg can not be independently worked without the use of the other leg. Furthermore, current bicycle operations are efficient while only working specific muscle groups in the leg. Hence, the user does not have an option to simultaneously exercise both the agonist and antagonist muscles through the cycle of rotation, i.e., quad and hamstrings, hip flexors and hip extenders. 
     It would be an improvement on the current art to create a unipedal cycle wherein each leg&#39;s movement is independent of the other. This aspect would serve to expand the effectiveness of bicycling in reconditioning of an injured leg. Independent operation of the legs would also increase the work output demands per unit time but not at the expense of overstressing the joints, muscles and soft tissues. It would be counterproductive if additional injuries were created. A device that overcomes the shortcomings as just described for a road bike or stationary bike is not disclosed in the prior art. 
     SUMMARY OF THE INVENTION 
     It an aspect of the invention to provide a unipedal cycle apparatus wherein the movement of each leg is independent of the other. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that can be alternatively bipedaling. 
     It is another aspect of the invention to provide a unipedal cycle apparatus where both legs must work fully throughout each pedal revolution. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that has the ability to work each leg independently. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that increases work output over bipedal cycles. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that increases work output without overstressing the joints, muscles and soft tissues. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that is used for exercise purposes. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that is used for conditioning. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that is used for therapeutic purposes. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that provides isotonic (same force) resistance. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that provides isokinetic (same speed) resistance. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that specifically addresses aerobic repetitive cyclic exercising of the hamstrings. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that specifically addresses aerobic repetitive cyclic exercising of the hip flexors. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that works the hamstrings and hip flexors on the upstroke of the pedaling motion. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that increases muscle strength without the risk of tightening and overstrengthing. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that does not promote muscle injury. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that works the abdominals muscles. 
     It is another aspect of the invention to provide a unipedal cycle apparatus to exercise both the agonist and antagonist muscles through the cycle of rotation. i.e., quad and hamstrings, hip flexors and hip extenders. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that is inherently safe. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that is user friendly. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that has an adjustable crank arm to lessen or increase the range of motion of the leg in pedaling. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that has adjustable pedals to alter demands on the different muscles being exercised. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that has an adjustable seat that be adjusted vertically thereby allowing for a variation of leg length and that be adjusted horizontally thereby allowing for different positioning fore and aft relative to the hub. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that is adaptable to any variety of resistance methods such as electromagnetic, friction belt, disc brake and hydraulic and a variety of resistance controls such as isotonic and isokinetic. 
     It is another aspect of the invention to provide a unipedal cycle apparatus that works each leg indendently with varying resistance. 
     It is a final aspect of the invention to provide a unipedal cycle apparatus that can be applied to either a stationary or road bicycle. 
     The invention is a pedal apparatus having a left pedal attached to a left crank and a right pedal attached to a right crank wherein the pedal apparatus comprises a left drive system connected to the left crank and a right drive system connected to the right crank such that the left drive system is substantially identical to the right side drive system and wherein a pedalling resistance on the left pedal can be set independently of a pedalling resistance on the right pedal. The pedal apparatus further comprises a split hub assembly having two central axles, wherein one axle is connected to the left side drive system and the other axle is connected to the right side drive system, such that the split hub assembly is selectively operable by the user as a bipedal apparatus having the left pedal and the right pedal rotating synchronously thus causing the invention to behave as a standard pedal apparatus. The split hub assembly utilizes a plunger and an activation rod wherein the user activates the rod to cause the plunger to lock together the right and left drive assemblies whereby the left pedal and the right pedal rotate synchronously. The drive system further comprises a left brake system whereby the brake system provides resistance to the left drive system and a right brake system whereby the right brake system provides resistance to the right drive system. An electronics module independently reads encoded data from the left drive system and from the right drive system whereby the data is translated into measurements of power, distance traveled and speed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a stationary unipedal cycle apparatus. 
     FIG. 2 is a right side view of the stationary unipedal cycle apparatus. 
     FIG. 3 is a left side view of the stationary unipedal cycle apparatus with the front and rear encoder protective shields removed. 
     FIG. 4 is an cross-sectional view of the split hub assembly of the stationary unipedal cycle apparatus. 
     FIGS. 5A-5C illustrate a flow diagram of the software routine run by the electronics module. 
     FIG. 6 is the optical encoder circuit used to provide the optical data necessary for the Motorola 68HC11 microprocessor to perform measurement of the user&#39;s Power, Distance and Speed values. 
     FIG. 7 is the motor driver circuit. 
     FIG. 8 is the switching circuit utilized to receive push-button entries for rider requests/feature selections. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is an isometric view of stationary unipedal cycle apparatus  10 . In the preferred embodiment, each side of stationary unipedal cycle apparatus  10  has its own pedal, crank, drive system and flywheel. The present invention utilizes a split hub assembly to give it the ability to offer two modes of operation: unipedal or bipedal. Unipedal mode is when each crank is functioning independent of the other. Bipedal simulates the normal operation of a bicycle. 
     In addition to the concept of apparatus  10  being applied to the stationary bike as described herein, the unipedaling concept can also be applied to a road bike. The concept of the foot pedal and foot crank provides the user independent leg resistance for a tailored exercise/rehabilitation program can likewise be extended to the user&#39;s arms via the addition an arm pedal and arm crank to provide the user independent arm resistance for a tailored exercise/rehabilitation program while simultaneously exercising the legs. In other words, apparatus  10  could be configured as an aerodyme bike, except with the added benefit of the user&#39;s legs and arms being able to be independently worked with a varying resistance applied to each crank. 
     FIG. 2 is a right side view of stationary unipedal cycle apparatus  10 . When describing operation of the drive system of apparatus  10 , forward motion will be considered in a clockwise direction when looking at apparatus  10  form the right side. This forward motion applies energy directly into apparatus  10 . A counter-clockwise motion does not apply energy into apparatus  10 . 
     All components of the invention are mounted to support frame  5 . Support Frame  5  is made out of tubular steel. The drive system components for the right side are functionally identical to the drive system components of the left side except for axles  60 / 62  and plunger  52 , which will be discussed in greater detail within the following paragraphs. Drive system components for the right side consist of the following items: pedal  24 , crank  48 , drive sheave  16 , drive belt  32 , idler pulley  28 , idler tensioner  94 , flywheel  20  and flywheel sheave  44 . Drive sheave  16  has a seventeen inch diameter and is constructed out of aluminum. Circular cut-outs  7  in drive sheave  16  help to reduce the overall weight of apparatus  10 . Drive belt  32  is an eight rib PolyV belt. The diameter of the remaining components, where applicable, are two and one half inches for idler pulley  28 , eight inches for flywheel  20  which is constructed out of cast steel, and two inches for flywheel sheave  44 . 
     An applied force on right pedal  24  turns crank  48  in a clockwise direction. Crank  48  is affixed to right axle  62  of split hub assembly  100 . An adjustable pedal  24  would allow the user to alter demands on the different muscle groups being exercised. Also, an adjustable crank  48  would allow the user to lessen or increase the range of motion of the limb in pedaling. An adjustable seat (not shown) to apparatus  10  would not only allow a variation of the user&#39;s leg length, but also in the possible positions over pedals  22 / 24 , thus changing the movements and demands of the user while pedaling. 
     A detailed description of split hub assembly  100  and its components will be discussed within when reference is made to FIG.  4 . As right axle  62  is turned about its axis of rotation in the forward clockwise direction, roller clutch bearings  64  (reference FIG. 4) are engaged to rotate right drive sheave  16  about the same axis. Drive belt  32  is wrapped tightly around drive sheave  16 , idler pulley  28  and flywheel sheave  44 . As drive sheave  16  moves forward, drive belt  32  rotates flywheel sheave  44  in a clockwise direction, which likewise rotates flywheel  20  in a clockwise direction. A forward moving drive belt  32  serves to rotate right flywheel  20  at a ratio of 8.5 to 1. 
     Two optical encoder disks  63  and  65  are used to provide optical data for the onboard electronics; right axle encoder disk  63  is located on the outboard side of right axle  62  while right flywheel encoder disk  65  is located on the outboard side of flywheel  20 . Optical encoders  63  and  65  are not shown in FIG. 2 due to their positioning behind front and rear protective encoder shields  15  &amp;  17 . Because of the symmetry between the right and left sides of apparatus  10 , a representation of optical encoder disks  63  and  65  can be seen in FIG. 3 by referencing left axle encoder disk  66  and left flywheel encoder disk  67 . The left side protective encoder shields have been removed for the purpose of illustrating location of optical encoder disks  66  and  67 . 
     Idler puller  28  serves to provide continuity between drive sheave  16  and flywheel sheave  44  by allowing tensioning adjustment to drive belt  32 . Tension is increased to drive belt  32  by loosening tensioner nut  23  and rotating tensioner handle  29  in a clockwise direction until the desired tension level is reached. Tightening tensioner nut  23  ensures that the tension in drive belt  32  is maintained. Machined slot  11  in idle tensioner  94  allows for adequate adjustment. Idler pulley  28  is affixed to a frictionless bearing which encloses a small shaft (not shown) that is part of idler tensioner  94 . The entire assembly is fastened to diagonal cross member  6  of apparatus support frame  5 . 
     The brake system of apparatus  10  utilizes a resistance that is provided to the right side drive system via friction band brake  36 . As brake band  36  is tightened, the torque required to rotate drive sheave  16  is increased. Brake band  36  is wrapped around brake rim  49 . Brake rim  49  is a fifteen inch diameter by three quarter inch wide aluminum rim fastened to the inside of drive sheave  16  such that the two rotate as one unit. One end of brake band  36  is fastened to brake cylinder  41 . Brake cylinder  41  is an aluminum cylinder centered around and secured to the shaft of right DC gear motor  40  (shown in FIG.  3 ). The opposite end of brake band  36  is fastened securely to an adjustable brake band anchor  37 . Anchor  37  can be adjusted with a tensioner screw (not shown) to provide fine changes in brake band tension. Anchor  37  is attached to left motor support bracket  43 . When right gear motor  40  shaft is rotated clockwise by an electrical signal, brake cylinder  41  is also rotated clockwise, thus causing brake band  36  to tightened around brake rim  49 /drive sheave  16 . 
     FIG. 3 is a left side view of stationary unipedal cycle apparatus  10  with the front and rear protective shields removed. All left side components are functionally identical to the right side components, except for axles  60  and  62  and plunger  52 , which will be described in greater detail when reference is made to FIG.  4 . When describing operation of the left drive system of apparatus  10  as viewed from the left side, forward motion is in a counter-clockwise direction. Thus, forward motion is opposite that of the direction as viewed from the right side. This forward motion applies energy directly into apparatus  10 . A clockwise motion does not apply energy into apparatus  10 . 
     The drive system components for the left side consist of the following: pedal  22 , crank  46 , drive sheave  14 , drive belt  30 , idler pulley  26 , idler tensioner  94 , flywheel  18  and flywheel sheave  42 . Drive sheave  14  has a seventeen inch diameter and is constructed out of aluminum. Circular cut-outs  7  in drive sheave  14  help to reduce the overall weight of apparatus  10 . Drive belt  30  is an eight rib PolyV belt. The diameter of the remaining components, where applicable, are two and one half inches for idler pulley  26 , eight inches for flywheel  18  which is constructed out of cast steel, and two inches for flywheel sheave  42 . 
     An applied force on left pedal  22  turns crank  46  in a counter-clockwise direction. Crank  46  is affixed to left axle  60  of split hub assembly  100 . An adjustable pedal  22  would allow the user to alter demands on the different muscle groups being exercised. Also, an adjustable crank  46  would allow the user to lessen or increase the range of motion of the limb in pedaling. An adjustable seat (not shown) to apparatus  10  would not only allow a variation of the user&#39;s leg length, but also in the possible positions over pedals  22 / 24 , thus changing the movements and demands of the user while pedaling. 
     A detailed description of split hub assembly  100  and its components will be discussed within when reference is made to FIG.  4 . As left axle  60  is turned about its axis of rotation in the forward counter-clockwise direction, roller clutch bearings  64  (reference FIG. 4) are engaged to rotate left drive sheave  14  about the same axis. Drive belt  30  is wrapped tightly around drive sheave  14 , idler pulley  26  and flywheel sheave  42 . As drive sheave  14  moves forward, drive belt  30  rotates flywheel sheave  42  in a counter-clockwise direction, which likewise rotates flywheel  18  in a counterclockwise direction. A forward moving drive belt  30  serves to rotate left flywheel  18  at a ratio of 8.5 to 1. 
     Two optical encoder disks  66  and  67  are used to provide optical data for the onboard electronics; left axle encoder disk  66  is located on the outboard side of left axle  60  while left flywheel encoder disk  67  located on the outboard side of flywheel  18 . The left side encoder shields have been removed for the purpose of illustrating location of the optical encoder disks. With the left shields in place, they are identical to front and rear protective encoder shields  15  &amp;  17 , as shown in FIG.  2 . 
     Idler puller  26  serves to provide continuity between drive sheave  14  and flywheel sheave  42  by allowing tensioning adjustment to drive belt  30 . Tension is increased to drive belt  30  by loosening tensioner nut  21  and rotating tensioner handle  27  in a counterclockwise direction until the desired tension level is reached. Tightening tensioner nut  21  ensures that the tension in drive belt  30  is maintained. Machined slot  12  in idler tensioner  92  allows for adequate adjustment. Idler pulley  26  is affixed to a frictionless bearing which encloses a small shaft (not shown) that is part of the idler tensioner  92 . The entire assembly is fastened to diagonal cross member  6  of apparatus support frame  5 . 
     The brake system of apparatus  10  utilizes a resistance that is provided to the left side drive system via a friction band brake. As brake band  34  is tightened, the torque required to rotate drive sheave  14  is increased. Brake band  34  is wrapped around brake rim  47 . Brake rim  47  is a fifteen inch diameter by three quarter inch wide aluminum rim fastened to the inside of drive sheave  14  such that the two rotate as one unit. One end of brake band  34  is fastened to brake cylinder  39 . Brake cylinder  39  is an aluminum cylinder centered around and secured to the shaft of a DC gear motor  38  (shown in FIG.  2 ). The opposite end of brake band  34  is fastened securely to an adjustable brake band anchor  35 . Anchor  35  can be adjusted with a tensioner screw (not shown) to provide fine changes in brake band tension. Anchor  35  is attached to right motor support bracket  45 . When left gear motor  38  shaft is rotated clockwise by an electrical signal, brake cylinder  39  is also rotated clockwise, thus causing brake band  34  to tightened around brake rim  47 /drive sheave  14 . 
     Electrical signals are sent to gear motors  38  and  40  from a printed circuit board located beneath power shield  19 . Layout of the printed circuit board is well known in the art. These signals are the direct result of a computer-controlled function to increase or decrease the resistance in drive sheaves  14 / 16 . The rider controls the application and magnitude of the resistance with entry buttons located on display console  90 . The rider may also choose to independently adjust resistance to one side or the other, or simultaneously adjust resistance to both drive sheaves  14 / 16 . 
     FIG. 4 is an cross-sectional view of split hub assembly  100  of stationary unipedal cycle apparatus  10 . Hub assembly  100  is capable of providing two modes of operation: bipedal or unipedal mode. The bipedal mode involves the rider pedaling apparatus  10  as one would a traditional bicycle. In this mode, plunger  52  is engaged causing left and right cranks  46  and  48  to be physically connected and positioned  180  degrees from each other. Both left and right drive sheaves  14  and  16  are propelled as a single unit by the downward strokes of each leading leg. 
     In the unipedal mode, plunger  52  is dis-engaged allowing the left and right pedals  22  and  24  to turn independently. In this mode, the left and right drive sheaves  14  and  16  are likewise propelled independently by the forward downstroke and the aft upstroke of each leg. 
     Split hub assembly  100  consists of two central thirty millimeter steel axles  60  and  62 . Each axle is enclosed by a one-way roller clutch bearing  64  (part number INA HFL 3030), and complimentary radial bearings  82  (part number INA HK 3012) which in turn are housed within drive shaft  56 . Left and right drive sheaves  14  and  16  are threaded onto the outside end of drive shaft  56 . Each drive shaft is housed within a set of double row angular contact bearings  76  (part number NTN 5210AZZ), which are enclosed within hub housing  51 . Hub housing  51  is a custom machined steel housing. Hub housing  51  is attached to diagional cross member  6  via hub bracket  50 . Central square cavity  105  is common to each axle. Spring loaded plunger  52  enters through right axle  62  through common cavity  105  to engage left axle  60  when actuated. Thus, left and right axles  60  and  62  may be “connected” or “disconnected” by the manual insertion or retraction of plunger  52  into or out of the left side cavity  105  located along the axis of rotation. 
     In the unipedal mode, hub assembly  100  is disconnected and plunger  52  rests solely in right axle  62 . This permits left axle  60  to rotate independently of right axle  62 . Clockwise (forward) rotation of right pedal  24  causes the forward rotation of right crank  48  and right axle  62 . With forward rotation of right axle  62 , one-way roller clutch bearings  64  engage right drive sheave  16 , causing it to also rotate in a clockwise direction. The identical sequence is followed for counterclockwise (forward) rotation of left pedal  22 , with the appropriate left side components. With either side, reverse pedaling results in no movement of associated drive sheave  14  or  16 . This is a result of one-way roller clutch bearings  64  which “free wheel” when either axle  60  or  62  is rotated in a reverse direction. 
     In the bipedal mode, split hub assembly  100  is connected by moving plunger  52  forward in central cavity  105  by manually actuating plunger actuator rod  54  so that plunger  52  engages both left and right axles  60  and  62 . This action permits both left and right drive sheaves  14  and  16  to rotate together as if axles  60  and  62  were a single unit. In this mode, as with the unipedal mode, roller clutch bearings  64  permit both drive sheaves  14  and  16  to rotate together in the forward direction but do not cause them to rotate in the reverse direction. 
     Split hub assembly  100  consists of two sets of drawn cup roller clutch bearings  64  that provide the one way rotation of drive shafts  56  on either side. Assembly  100  also contains thrust needle roller bearings  78  (part number Torrington FNTA 3047), radial needle roller bearings  82 , double row angular contact bearings  76 , thrust washers  80  (part number Torrington FTRA 3047), wave springs  68  (part number Smalley SSR 0162) and  70  (part number Smalley SSB 0354), and retaining clips  72  (Rotoclip Part No. SH-118) and  74  (Rotoclip Part No. HO-354) for each of axles  60  and  62 . All components are contained in a single steel housing  50  which is welded directly to the bicycle frame via hub bracket  51 . 
     An electronics module is contained within display console  90 . The electronics module reads optically encoded data from spinning flywheels  18  and  20  and spinning axles  60  and  62 . This data is then translated into measurements of Power (in Watts), Distance traveled, and Speed (both RPM and miles per hour), which can be displayed via light emitting diodes (LEDs) contained in display console  90 . Functioning in an isotonic (same force) resistance mode, the electronics module serves to energize two identical gear motors  38  and  40 , which are coupled to two respective brake bands  34  and  36  that are wrapped around respective drive sheaves  14  and  16  allowing resistance to be applied to each leg simultaneously or individually, according to the needs of the rider. The gear motors contain encoders which provide the means for controlling and producing fine rotational movement. Functioning in an isokinetic (same speed) resistance mode, the electronics module maintains the rider&#39;s speed by automatically adjusting gear motor&#39;s  38  and  40  resistance several times a second. If the rider is pedaling in unipedal mode, the resistance levels for each leg will vary according to the output of each leg such that the same speed is maintained if in an iso-kinetic mode. Appropriate gear levels are also displayed to the user via display console  90  from Level 0 to Level 10. In addition, an elapsed timer circuit provides a resettable clock. 
     FIG. 5 is a flow diagram of the software routine run by the electronics module. At the heart of the electronics module is the Motorola 68HC11 microprocessor (not shown); 37 I/O ports are utilized to receive pulse data and push-button entries, to energize motors  38  and  40 , and to light up LED displays. Software written in C is programmed to run in a while-forever loop. The software continuously polls the I/O ports for user requests. 
     A software interrupt routine is performed once per second to retrieve data from the opto sensors  63  and  66  located at drive sheaves  14 / 16  and the opto sensors  65  and  67  located at flywheels  18 / 20 . Once “fresh” data is entered, the Power &amp; Velocity calculations take place. If a gearing operation occurs immediately prior to the 1-second interrupt flag, data is not collected so as not to disturb the motor actuation. 
     FIG. 6 is the optical encoder circuit used to provide the optical data necessary for the Motorola 68HC11 microprocessor to perform measurement of the user&#39;s Power, Distance and Speed values. The optical encoder circuit is also used to determine gear levels of apparatus  10  which are visual indicators of reistance levels to each leg. Opto-interrupter sensors (not shown) are mounted to each drive sheave  14  and  16  and each flywheel  18  and  20  in order to provide the optical data to the 6811 microprocessor. The gear levels are determined via optical encoders (not shown) encased within the gear motors. As the motor shaft turns, pulse data is sent to the 6811 microprocessor through the same ports as the Power/Velocity sensors, however, the data is sent through a different channel via a digital switch integrated circuit. 
     As previously described, four optical encoder disks (two on each side) are used to provide optical data for the on-board electronics via the opto-interrupter sensors; left axle encoder disk  66  is located on the outboard side of left axle  60  while left flywheel encoder disk  67  is located on the outboard side of flywheel  18 ; and right axle encoder disk  63  is located on the outboard side of right axle  62  while right flywheel encoder disk  65  is located on the outboard side of flywheel  20 . Each optical encoder disk consist of a 60-line code that is used to provide the optical data necessary for the electronics module to perform measurement of Power, Distance and Speed. 
     During the 1-second interrupt, a 0.32 second window is opened for either the left or right side&#39;s drive sheave  14 / 16  and the left or right side&#39;s flywheel  18 / 20  (according to which side has requested data). Sequentially, the number of pulses that are sensed in the allotted time are entered into variables, and manipulated in the main routine to arrive at an RPM value. Next, an instantaneous Power value is calculated by 
     
       
           P =( I*alpha*omega )  
       
     
     where I is the flywheel Moment of Inertia, alpha is the difference in sequential angular velocity measurements, and omega is the current angular velocity in radians/second. This instantaneous Power value is added to all previous Power measurements to arrive at a current total value in watts. Note that in the event of a deceleration, negative Power is added to reduce the overall Power value. In addition, the current gear level is taken into account to increase the added Power by a certain factor related to the amount of added Torque the rider adds to the system via drive sheaves  14 / 16 . 
     Distance is measured by the number of pulses that are counted continuously through the 6811&#39;s pulse accumulator. Knowing the physical parameters of the rotating flywheel allows a direct calculation of tenths of a mile from the number of pulses, assuming a standard 26″ diameter wheel is spinning in place of the flywheel. Likewise, Velocity is measured directly from the pulse data in RPM, and converted to miles/hour (mph) via software. 
     The gear levels of apparatus  10  are likewise determined via optical encoders encased within the gear motors. As the motor shaft turns, pulse data is sent to the 6811 microprocessor through the same ports as the Power/Velocity sensors mentioned above, however, the data is sent through a different channel via a digital switch integrated circuit. The 6811 microprocessor can dictate exactly how far the motor/brake band system rotates (thereby increasing or decreasing resistance) due to the pulse data received from the optical encoders. The lowest gear level (0) is determined by a contact sensor (not shown) mounted directly to the bike frame to act as a limit switch. 
     FIG. 7 is the motor driver circuit used by the Motorola 68HC11 microprocessor to provide forward and reverse directional inputs to motors  38  and  40 . Motors  38  and  40  are twelve volt DC gear motors having a maximum torque of sixty inches/pound and a constant 10.7 RPM. A driver circuit uses two motor driver (i.e. LM 18293) chips in an H-bridge configuration allowing for forward and reverse directions. No changes to the flywheels would be required in order to reverse pedal but the roller clutches bearings  64  do not permit reverse pedalling and would need to be changed using techniques well known in the art. A user pedalling in a reverse direction adds a different demand profile on the user&#39;s muscles being worked. Over-current protection is required. 
     FIG. 8 is the switching circuit contained within display console  90  and utilized by the Motorola 68HC11 microprocessor to receive push-button entries for rider requests/feature selections. The push-button entry module allows the rider to view Power and Velocity data from either the left or the right side. Other rider entries may include any of the following: Gear UP, Gear DOWN, Gear Reset (to Level 0), Timer Reset, Odometer Reset, Simultaneous Gear Shift, and Individual Gear Shift (L/R). 
     All data is displayed using numerical format 7-segment standard or 14-segment alphanumeric LED displays. In the 14-segment option, messages are displayed to prompt the rider for entries. These “data windows” display the following: Power (in Watts or Kcal/Hr), Distance Traveled (in miles/km), Elapsed Time, Gear Level (0-10), and Velocity (in RPM or MPH). In addition, LEDs are utilized to indicate the following: Units for Power/Velocity/Distance, BI-Pedal operation, UNI-Pedal operation, Simultaneous Shift Mode, Individual Shift Mode (L/R), and Power On. 
     The electronics module also incorporates software routines for special program features such as hill-climbing patterns, hill/valley combinations, and other workout routines. These programs are highlighted by LED arrays which keep track of the pace and location of the rider within the routine. 
     All the electronics of apparatus  10  are powered by a Zenith ZPS-30 watt 12 v/5 v switching power supply capable of two and three amps peak, respectively. This unit is UL listed. 
     The detail described here is transmutable with other similar components. The Motorola 6811 microprocessor may be replaced with an Intel or other capable microprocessor having any number of I/O ports. Any motor driver chip may be used as long as it is capable of drawing the required current to energize the gear motors. Likewise, gear motors  38  and  40  may be replaced with higher torque-output motors having a different torque ceiling and RPM than that specified herein. The encoders used to collect pulse data may be made with higher (or lower) resolution, depending on the brake band resistance values required. The selected power supply may be replaced by another source having varying 12 v/5 v output values. 
     While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.