Patent Publication Number: US-6910992-B2

Title: Tandem exerciser and power generator

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to tandem exercisers, kits and methods thereof, for exercising two riders simultaneously so as to work the upper and lower portions of their bodies, and more particularly to human-powered tandem apparatus that optionally converts work or motion created by the users or riders into usable electric, fluidic, or motive power. 
     BACKGROUND OF THE INVENTION 
     As is known, various types of exercising devices and machines are popular in today&#39;s society. In recent decades, as the awareness of the importance of cardiovascular, skeletal muscle and aerobic training has risen, so too has demand increased for improved exercise equipment. Gyms and health clubs typically offer a variety of sophisticated and expensive equipment, such as stationary versions of bikes, recumbent bikes, treadmills, rowers, stair climbers or steppers, ellipticals and cross-country skiing. All of this equipment is designed and manufactured to be used by only one rider or user at a time. So, even though the public has become more aware that consistent and intelligently applied exercise can slow the effects of aging and thereby lengthen life span, overcome physical and metabolic disease, control weight and pre-disease states, there is little, if any, exercise equipment that encourages mutual, simultaneous use; provides social opportunities through its face-to-face contact; as well as mutually concurrent monitoring of user exercise. Specifically, there is little, if any exercise equipment that simulates popular forms of mutual or concurrent exercise and that allows face-to-face socialization. 
     Exercising the muscles of the body to increase the overall aerobic capacity, upper and lower body strength and stamina, and lean muscle mass of a single individual by combining forward leg pedaling with arm pumping free weights is one of the types of known exercise. However, arm pumping with free weights is often cumbersome, creating storage problems of the free weights, damage to floors and walls, and possible injuries to nearby individuals. In addition, arm pumping free weights is not easily coupled for objectively measuring exercise output. Therefore, there is a need for an exercise device, apparatus or exerciser that mechanically couples both arm pumping and forward leg pedaling. There is also a need for harnessing and transmitting this exercise power and converting or transducing it into usable power. 
     The development of devices that use cycling wheels or flywheels to provide the resistance for muscle contraction eliminated the problems inherent with handling free weights, but also created new ones. Even the classic tandem bicycle built for two riders does not allow for upper body exercise, and the riders both face the direction in which they travel, thereby making it difficult to socialize and monitor the performance of the other user. The tandem bicycle further limits the view of the rider that sits directly behind the lead rider, creating a situation where the forward view for the back rider never changes. 
     In the instant invention, the concept of using an exerciser where two riders face each other, so as to mutually encourage and monitor performance and output of the other rider, yet where each rider must pedal forward, is believed to be novel. The power transmission and transduction system described herein, requires mutual forward pedaling by both face-to-face users or riders and is also believed to be novel. 
     There is therefore a need to provide a new mechanical exerciser for working the upper and lower body portions of dual riders that overcomes the problem of one rider located directly behind and out of the line-of-sight of the other rider, and thereby not working or exercising equitably. 
     It is an object of the present invention to couple the mutual forward pedaling motion generated during tandem exercise of the upper and lower portions of the bodies of dual riders. 
     It is an object of the present invention to optionally couple the forward power generated during tandem physical exercise to a generator of electrical, fluidic (gas or liquid) or motive power, that would either be concurrently used or stored for future use. 
     It is another object of the present invention to provide an integrated two-person exerciser for optionally driving larger power generators for either immediate use or storage of this power. 
     It is still another object of the present invention to provide a dual human-powered apparatus for driving a variety of different makes and styles of power generators, power components, power equipment and other motive driven apparatus. 
     It is still yet another object of this invention to provide this tandem exerciser and power generator in a easily moved, easily stored, easy to use format, that is functionally tolerant of tandem users, capable of withstanding institutional usage encountered in universities, corporations, and commercial gyms, as well as third world countries. 
     It is still yet another object of this invention to provide this tandem exerciser and power generator as components or parts packaged in a kit or kits that are shipped to the retailer and/or customer and then assembled. 
     It is still yet another object of this invention to provide a method or methods for simultaneous tandem exercising and power generation. 
     The aforementioned background has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention as will be described. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the following illustrations, and the written disclosure of the Detailed Description of the Invention. 
     SUMMARY OF THE INVENTION 
     These and other objects of the invention are provided in a tandem exerciser for working the upper and lower bodies of two facing, forward pedaling riders, and for transmitting and transducing the motive power thereby generated into useful electrical, fluidic or mechanical power. 
     In the preferred embodiment, the tandem exerciser includes a frame, a suspended flywheel, two facing seats, and structural elements for supporting both ends of the frame. A power transmission and transduction system is comprised of a chain-and-sprocket system coupled to the flywheel, where the flywheel is belt coupled to a power generator producing twelve-volt D.C., A.C. electricity, or driving an air compressor, fluid pump, or other motive-powered systems. 
     A proximal pedal crank is chain coupled to a distal pedal crank, through two sprocket wheels coupled together by a synchronizing bicycle chain. This chain is twisted slightly less than one-hundred-eighty degrees, and mounted on the opposing sprocket wheels that are oppositely offset from the vertical plane of the frame. This offset prevents the chain from physically contacting and damaging itself. It also allows both pedal cranks to be forward pedaled by their respective facing riders. An alternating handlebar crank is also mechanically coupled to the distal pedal crank thereby harnessing exercise from the upper bodies of both riders. 
     This unique facing, forward pedaling feature of this invention allows tandem riders or users to closely monitor the exercise rate, or work level of the other user. Encouragement and other social action can then take place in a face-to-face manner. 
     The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner of modifying the invention as will be described. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the following Detailed Description of the Invention, which includes the preferred embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the present invention. 
         FIG. 2  is a simplified side view of the forward directional drive from the pedal cranks of the present invention. 
         FIG. 3  is a front sectional view taken generally along line  3  of  FIG. 1 , of the present invention. 
         FIG. 4  is a front sectional view taken generally along line  4  of  FIG. 1 , of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 U.S.C. §112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. 
     The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts and members, which will be exemplified in the construction hereinafter described, and of which the scope will be indicated by the appended claims. 
     Referring now to the drawings, and specifically to  FIG. 1  thereof, a tandem exerciser is generally designated  10  and includes frame  12  having proximal and distal ends, and near and far sides. Frame  12  is suspended between front wheel assembly  14  and flywheel  16 . The flywheel  16  is suspended above the floor surface by gantry  18 , which is the distal end portion of frame  12  attaching to, and supporting flywheel  16 . The exerciser  10  also includes proximal saddle or seat  20 , and distal saddle or seat  22 , which allows tandem riders to directly face each other while exercising by forward leg pedaling and alternating arm pumping. 
     Continuing with  FIG. 1 , handlebar crank  24  is located on both near and far sides of frame  12 . The handlebar crank  24  is constructed of two substantially vertical crank members  26 ,  28  described as columns or tubes, which alternately pivot or rock about their attachment at the opposing ends or end portions of perpendicular cross member  30 . This cross member  30  is fixedly attached to the upper third portion of vertical frame column  32  or head tube that is centrally located on frame  12 . The upper portions of the bilateral handlebar crank  24  includes handlebars  34 ,  36  extending toward the first or proximal rider sitting on proximal seat  20  and the opposing handlebars  38 ,  40  extending toward the second or distal rider sitting on distal seat  22 . These handlebars  34 ,  36 ,  38 ,  40  extend upward and towards the upper body, shoulders or arms of the seated riders, respectively. Handlebars  36 ,  40  on the nearest side of frame  12 , and handlebars  34 ,  38  on the furthest side of frame  12  are constructed to generally resemble a “Y”-shaped, “V”-shaped or “U”-shaped outline or form. These shapes are meant as typical examples, and shall not be construed as limiting. 
     The two riders control and manipulate handlebars  34 ,  36 ,  38 ,  40  by grasping handles  42 ,  44 ,  46 ,  48 , respectively. During exercise the two riders alternately pump their arms by extending and contracting their arms against handles  42 ,  44 ,  46 ,  48  thereby moving handlebars  34 ,  36 ,  38 ,  40  and vertical crank members  26 ,  28  which alternately and longitudinally pivot both sides of handlebar crank  24 . The distance between the human riders and handles  42 ,  44 ,  46 ,  48  and handlebars  34 ,  36 ,  38 ,  40  allows for a comfortable and efficient range of motion for the arms and shoulders of each rider. Upper body, shoulder and arm pumping applied by the tandem riders to the handlebar crank  24  is then transmitted and transduced into forward pedaling rotation of distal pedal crank  50 . This movement transduction occurs at the bottom end of vertical crank members  26 ,  28  which are pivotally coupled to generally horizontal handlebar crank arms  52 ,  54  extending towards and pivotally coupled to the end portions of the respective pedal crank arms  56 ,  58 . 
     The distal pedal crank  50  is constructed of pedal crank arms  56 ,  58  with pedals  60 ,  62  respectively attached thereon. First or outer sprocket wheel  64  and second or inner sprocket wheel  66  are centrally attached to pedal crank  50  which is coupled to frame  12  so as to allow rotation. Both distal sprocket wheels  64 ,  66  are located on the far side of frame  12 . 
     The proximal pedal crank  68  is constructed of pedal crank arms  70 ,  72  with pedals  74 ,  76  respectively attached thereon. Sprocket wheel  78  is centrally attached to pedal crank  68  which is coupled to frame  12  so as to allow rotation. The proximal sprocket wheel  78  is located on the far side of frame  12 . 
     The frame  12  normally lies in a generally vertical plane and includes upper frame members  80 ,  82  that are laterally spaced, longitudinally and downwardly extending in the opposing proximal and distal directions. Below the upper frame members  80 ,  82  are intermediate frame members  84 ,  86  that are also laterally spaced, longitudinally and downwardly extending in the opposing proximal and distal directions. 
     These frame members  82 ,  84 ,  86 ,  88  as well as all other frame members, are described as columns or tubes, by way of example and not limitation, whose thickness and density are determined by individual requirements of strength and weight, thereby requiring some members to be substantially solid or hollow cross-sectionally. All the individual members or pieces used in the construction of frame  12  may also have various cross-sectional shapes, by way of example and not limitation, such as circular, oval, elliptical, triangular, rectangular or square and perform their function with equal effectiveness. Typically, the outer diameters of the frame members may vary generally between 0.875 to 3.5 inches, by 0.125 inch increments. 
     All of the hardware of the tandem exerciser  10 , especially frame  12  and its component members, columns or tubes may be made substantially of any rigid metal or combinations of metal, such as steel, Chromoly steel, iron and chromium and/or nickel-containing alloys, as well as aluminum, titanium or other weldable or heat-joinable metals. All component members of frame  12  may also be made lightweight by incorporating materials such as carbon-graphite fiber and/or metal-matrix composites, in whole or part. 
     The opposing longitudinal upper and intermediate frame members  80 ,  82 ,  84 ,  86  are connected at their centrally directed ends to generally upstanding vertical frame column  32 , also referred to as head tube. Support post  88  is inserted into and is positionally secured to the upper end of head tube  32  by welding or post collar. This support post  88  is used for mounting at least one display meter or monitor. 
     Continuing with  FIG. 1 , voltage meter  90  and reflective mirror  92  are pivotally or hingeally mounted to the upper end of support post  88 . The mirror  92  is reflectively juxtaposed to dial or face of the voltage meter  90  so as to allow the proximal rider to view voltage output as a type of performance output during exercise. Actual pedaling of the tandem exerciser  10  has yielded sustained voltages measured at seventeen volts D.C. by the voltage meter  90 . The voltage meter  90  may be one or more analog meters, measuring zero-to-eighteen volts D.C., such as the Sunpro CP8205 Voltmeter from Actron (Cleveland, Ohio). Alternatively, one or more analog meters that measures volts A.C., or one or more digital display meters that measures and displays volts A.C. or D.C. may be used. Another approach, by way of example and not limitation, would be to use one or more digital display performance meters that measures exercise work output and then instantly calculates and displays distance traveled, calories burned, watts produced, actual time, exercise time, single and/or dual heart rates and/or other indications of work, exercise or performance output. Such digital display meters may be obtained from Concept2, Inc. (Morrisville, Vt.), Nielsen-Kellerman (Chester, Pa.) or Kettler (San Antonio, Tex.), or other manufacturers of these standard performance meters used with many well known stationary exercise systems. Alternatively, the meter may be measuring and displaying fluidic power or potential power from either air compressors, in units of PSI, Bar, Kg/cm 2 , or KPA, or liquid pumps or motive power in revolutions per unit time. Either meter used would be connected electrically, optically or fluidically to one or more identical sensors or to different types of sensors measuring air pressure, fluid pressure, electrical output, or revolutions per unit time from the flywheel  16 , either directly or indirectly. 
       FIG. 1  further teaches that the downward end of vertical frame column  32  is connected generally midway between the ends of horizontal frame member  94 . Frame member  94  may also be referred to as cross tube or crossbar of frame  12 . The proximal end of crossbar  94  is rigidly connected to bottom bracket shell  96  located at the proximal end of frame  12 , through which the hub assembly  98  is secured and the proximal pedal crank  68  revolves. The distal end of crossbar  94  is rigidly connected to another bottom bracket shell  100  located at the more distal end of frame  12 , through which hub assembly  102  is secured and the distal pedal crank  50  revolves. 
     Extending frame member  104  projects longitudinally and in the proximal direction from bottom bracket shell  96  and generally bends downward and connects into front wheel assembly  14  that is used to support the proximal end of tandem exerciser  10 . This front wheel assembly  14  facilitates the roll-away and storage of the tandem exerciser  10  when not in use. The extending frame member  104  may be permanently fixed in position using welding methods, or alternatively, be adjustably secured in both longitudinal length and rotation using post collar. The front wheel assembly  14  is constructed from wheel  106 , axle  108 , and wheel bracket  110 . The front wheel assembly  14  is reinforced and secured to the horizontal frame member  94  by at least one strut  112  or stays. 
     Collapsible kickstand  114  is connected through hinge assembly  116  to pylon  118  projecting downward from the horizontal frame member  94 . The kickstand  114  is engaged after the tandem exerciser  10  is rolled to a desirable location, but before the riders mount their facing seats  20 ,  22 . Kickstand  114  is shaped as an inverted “T” in order to provide overall mechanical stability and safety during exercise, or productive use. Other kickstand formats or shapes may be used such as “A”-shaped, or inverted “Y” or “U”-forms. These shapes are meant as typical examples, and shall not to be construed as limiting. 
     At the proximal end of frame  12 , generally upstanding seat column  120 , also referred to as seat tube, is rigidly and fixedly secured to the proximal end of the upper frame column  80  and to bottom bracket shell  96 . The proximal ends of both the intermediate frame column  84  and crossbar  94  are also rigidly and fixedly attached to bottom bracket shell  96 . Seat  20  is adjustably connected to seat post  122  which telescopes within seat column  120 . Seat post  122  is vertically, horizontally and rotationally secured within seat column  120  by use of seat post collar  124  that may be tightened or expanded by turning an adjustment screw in the collar ends. Alternatively, seat post collars that use quick-release mechanisms and levers may also be used to secure seat post  122 . 
     At the distal end of frame  12 , another generally upstanding seat column  126 , also referred to as seat tube, is rigidly and fixedly secured to the distal end of the upper frame column  82  and to bottom bracket shell  100 . The distal ends of both the intermediate frame column  86  and crossbar  94  are also rigidly and fixedly attached to bottom bracket shell  100 . Seat  22  is adjustably connected to seat post  128  which telescopes within seat column  126 . Seat post  128  is vertically, horizontally and rotationally secured within seat column  126  by use of another seat post collar  124  that may be tightened or expanded by turning an adjustment screw in the collar ends. Again, an alternative approach may utilize seat post collars that incorporate quick-release mechanisms and levers to secure seat post  128 . 
     As illustrated in  FIG. 1 , the proximal and distal seat columns  120 ,  126  may both be inclined rearwardly away from the respective ends of frame  12 , for the comfort and proper foot placement of the users or riders. 
     Continuing with  FIG. 1 , the tandem exerciser  10  is suspended and supported at the distal end of frame  12  by a portion of the frame  12  designated as gantry  18 . This gantry  18  also attaches to, and supports flywheel  16  by connection to rotatable axle  130 . At least two chain stays  132  extends bilaterally, longitudinally and distally from the bottom bracket shell  100  and adjustably connects at their respective distal ends to the respective ends of axle  130  of flywheel  16 . These chain stays  132 , as well as other gantry members, are secured to their respective ends of axle  130  by axle nut  134 . At least two gantry-seat frame members  136  or columns are fixedly attached to the upper portion of seat column  126  and extend downward in a distal direction and outward relative to the vertical plane of frame  12  toward a fixed connection with the opposing ends of perpendicular base member  138  of gantry base frame  140 . At least one seat stay  142  on each side of frame  12  fixedly connects to the upper portion of each gantry-seat frame member  136  and extends downward so as to adjustably connect to the respective opposing ends of flywheel axle  130 . 
     Socket box  144  that includes electrical socket and toggle switch, is attached between the upper portions of gantry-seat frame members  136 . Alternatives to the electrical socket would include, but shall not be limited by, one or more twelve-volt D.C. output sockets, one or more A.C. output sockets, and/or one or more one-hundred-twenty volt A.C. sockets or outlets. The sockets or outlets are electrically connected to power generator  146  and/or to a twelve-volt battery or batteries electrically connected in series. 
     At least one pair of gantry-axle frame members  148  extend downwards and angularly outward from each end of the flywheel axle  130 . Each pair of gantry-axle frame members  148  are fixedly connected on their side of frame  12 , respectively, to about the middle third-portion of longitudinal base members  150  of gantry base frame  140 . 
     Longitudinal columns  152  extend angularly upward in the distal direction from the respective proximal ends of the two longitudinal base members  150  of gantry base frame  140 . Each longitudinal column  152  contains handle post  154  that adjustably telescopes so that the user can control the leverage needed to lift and roll-away the tandem exerciser  10 . At the distal ends of each handle post  154  are grip handles  156 . 
     Flywheel  16  is weighted near the outer rim or perimeter by using semicircular metal plate segments  158  securely attached to like metal plate segments on the opposing side of flywheel  16 . Each metal plate segment  158  weighs between six and twenty-four pounds, with a typical weight of about twelve pounds. Foam rubber or other compressable material may be used to cushion and inhibit the plate segments  158  from rattling and/or shaking loose during use of the tandem exerciser  10 . The added weight or mass of between eight-to-twenty-four plates further serves to regulate or equalize the rotational motion of the flywheel  16  by increasing the inertia of the flywheel  16  during use. Alternatively, the flywheel  16  may be a one-piece metal wheel machined or molded from a single metal or metal alloy, and resulting in a wheel approximately equivalent in total weight as the aforementioned flywheel  16 . 
     Power generator  146  is secured by mounting bracket  160  to the perpendicular base member  138  of the gantry base frame  140 . The power generator  146  is operationally coupled to the outer rim of flywheel  16  by flexible circular belt  162 . In this embodiment, the belt  162  is eighty-four inches in circumference. This length is meant to be exemplary, and is not to be construed as limiting because the circumference of flywheel  16  and the coupling distance to power generator  146  will effect the actual circumference of belt  162 . This circular belt  162  may be made of natural or synthetic materials. Commercially available examples of this circular belt  162  would include, but not be limited by, one or more conventional V-belts, drive belts or serpentine belts. Such belts are available from DAYCO (Tulsa, Okla.) and many other manufacturers and suppliers known to those skilled in the art. Primitive alternatives may include natural or synthetic rope, chain or gut materials fashioned into a makeshift belt. Alternatives to the belt system of power transmission and transduction would include direct gear-to-gear, or chain-and-sprocket systems. 
     The power generator  146  may be either twelve-volt D.C. generator, alternator (A.C. generator), air compressor or fluid pump. The twelve-volt D.C. electrical power may be stored in one or more twelve-volt batteries electrically connected by electrical cable  164  in series to the D.C. generator. The electrical power could also be stored in capacitors. The power generator  146  may be variously sized to match the work output from the tandem riders. An alternative to using an alternator would be to use a one-hundred-forty watt inverter that could be plugged into the twelve-volt D.C. socket of the socket box  144  and then produce one hundred twenty watts A.C. Such an inverter is available from RadioShack (Fort Worth, Tex.) as product number 22-145. 
     Alternatively, the motive power of the flywheel  16  itself may be directly harnessed and transduced for rotating or turning of various mechanically-powered equipment that mills, cuts or grinds various materials or objects. 
     Now turning mostly to  FIG. 2 , chain-and-sprocket system  166  is generally designated and is used to capture the work from two riders that are exercising their upper and lower bodies. This chain-and-sprocket system  166  is a portion of the overall power transmission and transduction system seen in  FIG. 1  that may also incorporate flywheel  16 , belt  162 , and various power generators  146 . As  FIG. 2  teaches, this chain-and-sprocket system  166  is used to uniquely and simultaneously transmit and transduce power from the arm and leg pumping and forward leg pedaling from both the proximal and distal tandem riders. 
     As illustrated, in  FIG. 2 , this chain-and-sprocket system  166  is constructed from proximal sprocket wheel  78  fixedly coupled to pedal crank  68  having crank arms  70 ,  72  located bilaterally. Both crank arms  70 ,  72  are turned at the point of the attached pedals  74 ,  76  by the forward pedaling feet of the proximal rider. The proximal end of synchronizing chain  168  is engaged to a portion of about thirty-nine individual sprockets  170  or teeth, as seen in  FIG. 1 , and located around the perimeter of sprocket wheel  78 . The number of sprockets per any sprocket wheel in the instant invention is only exemplary, and is not meant as limiting. This synchronizing chain  168  is then twisted or turned slightly less than one-hundred-eighty degrees at the distal end of chain  168 , and then typically engaged at the distal end to a portion of about thirty-nine sprockets  172 , as also seen in  FIG. 1 , located on the perimeter of inner sprocket wheel  66  which is fixedly coupled to outer sprocket wheel  64 . This synchronizing chain  168  now resembles a figure-eight laid on its side, as illustrated in FIG.  2 . It is this twist and figure-eight feature of the synchronizing chain  168  that allows both riders to pedal forward, relative to themselves and the direction in which they sit, as noted by the direction of arrows  174 ,  176  in FIG.  2 . Opposing rotations of the proximal and distal sprocket wheels  78 ,  66  are noted by arrows  178 ,  180 . Specifically, arrow  178  shows the clockwise rotation of sprocket wheel  78 , while arrow  180  shows a counterclockwise rotation of sprocket wheel  66 . Arrows  182 ,  184  illustrate the direction of chain uptake by the respective sprocket wheels  78 ,  66 . Without this twisted chain  168 , one of the riders would have to pedal backwards which is not efficient, nor equitable for the forward pedaling rider. 
       FIGS. 3 and 4  illustrate how the twist to the synchronizing chain  168  is maintained. In  FIG. 3 , the proximal sprocket wheel  78  is mounted off the vertical plane  186  and slightly negative, as indicated by line  188 . The degree of angle offset is between about negative one-half and negative ten degrees. In  FIG. 4 , the distal sprocket wheel  66  is also mounted slightly off the vertical plane  186  but slightly positive, as indicated by line  190 . The degree of angle offset is between about positive one-half and positive ten degrees. This results in both sprocket wheels  78 ,  66  being angled in opposite directions relative to the other. It also results in a relative difference in combined sprocket wheel angle of between about one and twenty degrees. This combined angle offset to the sprocket wheels  78 ,  66  is sufficient to generally prevent the sides or lengths of chain  168  from scrapping, cutting or otherwise physically contacting or damaging themselves during their close proximity at the center of the figure-eight loop. 
     Returning to  FIG. 1  to illustrate the power transmission and transduction system, exercise power is transmitted to flywheel  16  in the following manner. Both first and second sprocket wheels  64 ,  66  are fixedly coupled to pedal crank  50  having crank arms  56 ,  58  located on either side of frame  12 . Both crank arms  56 ,  58  are turned at the point of the attached pedals  60 ,  62  by the forward pedaling feet of the distal rider. Additionally, both tandem riders mutually and concurrently turn the first and second sprocket wheels  64 ,  66  by applying exercise motion to the handlebar crank  24  that is coupled to crank arms  56 ,  58 . Furthermore, the proximal rider also pedals forward and turns proximal sprocket wheel  78  that is operationally coupled by the twisted synchronizing chain  168  to the second sprocket wheel  66 , which turns the fixedly coupled first sprocket wheel  64 . 
     Continuing with  FIG. 1 , some portion of about fifty-two sprockets  192  of the first sprocket wheel  64  are operationally engaged to “drive chain”  194 . This “drive chain”  194  then engages and turns freewheel  196  that is coupled to the flywheel axle  130 , which in turn spins flywheel  16 . Freewheel  196  has between one to eight fixed or interchangeable sprocket wheels, which allows a corresponding number of gear ratios. Freewheel  196  with five sprocket wheels, as an example, would typically include fourteen, seventeen, twenty, twenty-four and twenty-eight sprockets. However, freewheel  196  would not be limited by only these sprocket combinations, or number of sprockets per sprocket wheel, because of the interchangeability of freewheel  196 . The sprocket wheels of the freewheel  196  are selected and chain-engaged by conventional derailer system  198  manipulated by either rider by use of gear lever  200  connected by cable to the derailer  198 . 
     A kit or kits would contain the parts and/or components of tandem exerciser  10  and optionally a power generator  146 . Such kit or kits would contain a completed frame, partially assembled frame or individual frame members that would be assembled into a completed frame. The kit or kits would also contain a power train, or power transmision and transduction system that would include handlebar crank  24  or individual crank members that would be assembled into handlebar crank  24 , chain-and-sprocket system  166  that includes single sprocket wheel  78 , dual sprocket wheel combination  64 ,  66 , at least two pedal cranks  50 ,  68 , a plurality of pedals  60 ,  62 ,  74 ,  76 , at least two chain assemblies  168 ,  194 , flywheel  16 , and belt  162  that couples the flywheel  16  to power generator  146 . The power generator  146  may be twelve-volt D.C. electrical generator, A.C. electrical power generator, combinations of D.C. generator and inverter, air compressor, gas pump, fluid pump, liquid pump, water pump, or other mechanically powered equipment for cutting, milling or grinding that is well known in the art. 
     Having described the preferred embodiment for the apparatus of the present invention, it will be apparent to one skilled in the art that other embodiments are also easily adapted by using the concepts discussed above. Accordingly, the invention should be limited only by the spirit and scope of the appended claims.