Abstract:
An exercise apparatus includes a frame designed to rest upon a floor surface, at least one crank rotatably mounted on the frame, and a discrete connector link having a first portion rotatably connected to each crank. A second portion of each connector link is constrained to move in reciprocal fashion relative to the frame, and a third portion of each connector link supports a foot platform. As a result, each foot platform is constrained to move through a generally elliptical path in response to rotation of each associated crank.

Description:
This is a continuation of U.S. patent application Ser. No. 09/300,545, filed on Apr. 27, 1999 (U.S. Pat. No. 6,387,017), which is a continuation of U.S. patent application Ser. No. 08/914,206, filed on Aug. 19, 1997 (U.S. Pat. No. 5,897,463), which is a continuation of U.S. patent application Ser. No. 08/497,377, filed on Jun. 30, 1995 (U.S. Pat. No. 5,707,321). 
    
    
     BACKGROUND OF THE INVENTION 
     The prior art is replete with many categories of exercise machines designed to exercise all major muscle groups of the human body. The most popular machines provide motion similar to activities such as bicycling, skiing, walking or stepping. The popularity of these machines is due to the effective low impact form of exercise enabled, as well convenience and time saving advantages. 
     In reference to machines such as stationary bicycles and steppers which involve the lower body, and cause the operators feet to move under resistance along constrained arcuate paths, evolving bicycle and stepper machine designs continue to incorporate foot motion paths of arcuate forms which are circular by definition. With bicycle machines, the circular path is caused by the simple relationship of the distance between the foot pedal and the pedal crank shaft. This constancy of motion is artificial to the human body, and is not considered by the inventor to be optimum during exclusive use for long term muscular development and conditioning. Bicycle machines do however offer a continuous motion which is preferable in order to ensure machine usage. 
     In reference to stepper machines, the arcuate path that the foot platforms travel about is a simple function of the distance between the foot platform and the pivot point of the platform support member. The stop and go motion of conventional steppers, in conjunction with the somewhat linear foot path, is considered by the inventor to be less ergonomic than the four bar stepper design of the present invention. 
     If one studies the motion paths of human feet during an activity such as walking or running, it will readily be observed that they travel along paths more accurately described as teardrop shaped. Whereas in the case of hill or stair climbing, the motion of ones feet closely resembles an ellipse or oval. The present invention provides a means to satisfactorily produce either motion, teardrop or elliptical, and does so in an efficient and economical way. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention provides a means to generate a number of characteristically distinct closed curves by using an arrangement of linkages. In all of the embodiments of this invention, the motion output of the linkages occurs at the foot pedals or foot platforms. Output of the linkages is also illustrated in several figures to additionally interface with a persons arms or hands in order to exercise upper body muscles. 
     Generally, the dynamic linkage portion of the mechanism may be described as containing three pin connected links, and in most of the illustrated embodiments, these link assemblies are interconnected by a common crank shaft. In this text, the general terms for these three dynamic links are crank, connector, and rocker. The frame of the machine serves as a fourth stationary link. The length of each of these four links, in combination with the arrangement in which they are pinned together, establishes the desired output exercise curve. 
     The first link is the shortest of the four links and is referred to as a crank link. The crank link is not to be considered figuratively as a drive link because this link receives force and is caused to rotate due to actions of the machine operator. It is possible however to drive this crank link independently by a motor or such if the design of a powered exercise machine is desired. 
     In the embodiments which provide a common crank shaft between a right and a left foot or hand receiving member, the attached cranks are diametrically opposed as to operate out of phase with respect to each other by 180 degrees. This phase difference of 180 degrees is not directly equatable to the relative positions of the foot platforms due to differences of instantaneous velocity or accelerations of the foot platforms at different path points. For the linkage system shown in the first figure, the platforms are positionally maintained out of phase by approximately 180 degrees, and the operator would not sense an imbalance of platform velocity or acceleration. 
     On those linkage mechanisms which generate pedal path curves where significant imbalance is present, it is not to be considered a disadvantage. When one considers the motion one&#39;s feet experience on your average walk or hike on rough ground, the feet experience quite random, unequal, and unsynchronous paths and velocities. The inventor, having traversed uncounted miles of rough forested terrain, can speak with authority as to the physical benefits derived from such variable and random action. 
     Although the most popular application of this invention would subject both feet along separate elliptical paths on two foot platforms out of phase with respect to each other by 180 degrees, another embodiment, intended primarily for a recumbent style exercise machine provides only one, relatively wide foot platform. In this embodiment the user reclines on a sloped bench and pumps the foot platform throughout an elliptical path with both feet side by side in a continuous, momentum gaining manner. This form of exercise is intended to be similar to squatting and standing exercises while eliminating strain and potential injury to back muscles. 
     Continuing now, the second link, referred to as a connector link, is rotatably attached to both the crank and the rocker. The foot platforms and/or hand receiving members are also rotatably attached to this connector link such that a total of at least three pin joints are always present and utilized at the connector link. The connector link cyclically translates while rotating a limited amount during machine operation. 
     The third link, referred as a rocker, is attached to the frame or stationary link at one end, and to the connector link at its opposite end. This rocker link will never completely revolve, but rather swing back and forth a limited amount. 
     The stationary link or fourth link rotatably secures the crank and the rocker to the machine frame. 
     In the preferred embodiment, the connector link is rotatably mounted at one distal end to the crank, and at an opposite distal end to a foot platform. Offset and between these opposite distal ends the crank is rotatably secured. 
     In order to ensure smoothest operation while cycling the foot platforms, particularly while they are at their minimum and maximum defection point, a flywheel may be coupled to the crankshaft. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be further described in conjunction with the accompanying drawings, which illustrate preferred embodiments, and wherein: 
     FIG. 1 is a perspective view of the first embodiment which incorporates means to drive a flywheel, and will be pedaled while the operator is seated. 
     FIG. 2 is a side view of the first embodiment and illustrates the linkages at different positions during the cyclic action. 
     FIG. 3 ( 3   a - 3   e ) are side views of four bar linkages which produce characteristically distinct and useful motion paths at the foot platforms. 
     FIG. 4 is a side view of an exercise machine and incorporates pivoting pedals upon the linkage mechanism of the first embodiment. 
     FIG. 5 is a side view of an exercise machine which utilizes a linkage system of the first embodiment, and also utilizes a separate linkage system connected to the foot platforms in order to maintain the platforms parallel and horizontal. 
     FIG. 6 is a side view of the first embodiment which incorporates a duplicate set of the four bar mechanism in order to maintain the foot platforms parallel and horizontal. 
     FIG. 7 is a perspective view of the dual linkage system shown in FIG.  6 . 
     FIG. 8 is a perspective view of the four bar mechanism of the first embodiment and shows two four bar mechanisms connected to one relatively wide platform for use with both feet when the operator is reclined. 
     FIG. 9 is a side view of an exercise machine which incorporates a four bar mechanism similar to FIG. 3 a.    
     FIG. 10 is a side view of an exercise machine which incorporates a four bar mechanism similar to FIG. 3 b.    
     FIG. 11 is a side view of an exercise machine which incorporates a four bar mechanism similar to FIG. 3 b,  and has a crank positioned for supplemental upper body exercise while the operator is seated. 
     FIG. 12 is a side view of an exercise machine which incorporates a four bar mechanism similar to FIG. 3 c.    
     FIG. 13 is a side view of another exercise machine which incorporates a four bar mechanism similar to FIG. 3 c  and has a crank positioned in close proximity to a seated operator to provide supplemental and optional upper body exercise. 
     FIG. 14 is a side view of an exercise machine which incorporates a four bar mechanism similar to FIG. 3 b,  and also allows for supplemental upper body exercise motion. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIG. 1, the linkage mechanism consists of three dynamic links. The first foot platform  2  is rotatably secured to first connector link  4  at first first foot platform joint  24 . The first crank radius  6  rotates with crank axle  8 . Crank axle  8  is rotatable secured to the machine frame. The end of first crank radius  6  is rotatably connected to the first connector link  4  as to cause that point of first connector link  4  to travel along a circular path. A first rocker link  10  is rotatably secured at one end to a distal end of first connector link  4 , and at the opposite end to a portion of the machine frame  12 . First foot platform  2  is illustrated at its uppermost position, and will be caused to travel along first elliptical path  3  as first crank radius  6  rotates one revolution. 
     At the opposite side of the machine, second crank radius  18  is secured to crank axle  8  at a diametrically opposite orientation of first crank radius  6 . Second connector link  16  is rotatable secured to second rocker link  20  and to second foot platform  14 . Second rocker link  20  pivots about a pin joint secured to a portion of the stationary machine frame  22 . Because the first and second cranks are orientated 180 degrees opposite, the second foot platform  14  illustrated at the lowermost position of second elliptical path  15  will be maintained approximately 180 degrees out of phase with the first foot platform  2  throughout the cyclic action. Crank pulley  26  may be installed to transmit torque to and from pulley  30  and pulley shaft  32  if a flywheel and/or upper body crank arms are to be installed. A V-belt  28  is illustrated between crank pulley  26  and pulley  30 , however a suitable sprocket or timing pulley may be used with a roller chain or timing belt respectively. 
     Referring now to FIG. 2, the three dynamic links are illustrated at multiple positions along the cyclic motion in dashed lines. Crank link  36  rotates once about crank shaft  38  for each complete cycle of the coupled connector link  34  and rocker link  44 . Connector link  34  is near the bottom of its cycle, and preferably causes a connected (unillustrated) foot platform to travel along an elliptical path in a counter clockwise direction as the operator faces to the left. In this regard, the linkage mechanism may be operated in either direction unless additional mechanical elements such as one way clutches or bearings are incorporated into the design. 
     Directing attention now to FIG. 3, five variations of four bar linkages are shown which will cause a foot platform to travel about a closed curve useful when performing exercises. Variations in the shape of the closed curves may be achieved by modifying link lengths and rearranging the points of rotation. By so doing, the curves may approximate near perfect ovals to the aforementioned tear drop shape. 
     Beginning at FIG. 3 a,  rocker link  54  and crank radius  48  are rotatably secured to the base at  56  and  50  respectively. Both base points are positioned approximately in line and perpendicular to the major axis of the elliptical path  60  formed as the foot platform joint  58  of connector link  52  traverses through its cyclic action. 
     Referring now to FIG. 3 b,  crank radius  62  revolves about a point fixed to the machine frame or base  64 . Rocker link  68  oscillates about a different point of the machine frame or base  70 . Coupled between crank radius  62  and rocker link  68  the connector link  66  defines the motion path  74  of the foot platform mounting joint  72 . The arrangement and proportions of the dynamic links shown in FIG. 3 b  enables the operator to stand and supplementally rotate the crank radius  62  by hand. A portion of the connector link of FIG. 3 b  is always positioned between the base points. 
     Referring now to FIG. 3 c,  crank radius  76  is rotatable secured to base  78 , and rocker link  82  pivots about base  84 . The elliptical path  88  created at foot platform joint  86  during the cyclic motion of connector link  80  is of a relatively high length to width ratio. Base points are located relatively parallel to the major axis of the depicted ellipse. 
     Directing attention now to FIG. 3 d,  rocker link  94  pivots about base  98  and is rotatably secured to connector link  96 . Crank radius  90  revolves about a point fixed on base  92  and causes foot platform joint  100  to define a closed curve  102  resembling the capital letter ‘D’. Although FIG. 3 d  is similar to the linkage shown in FIG. 3 c,  minor changes to the crank and the connector in conjunction with substantially shortening and repositioning the rocker results in a characteristically distinct curve. 
     Referring now to FIG. 3 e , crank radius  104  revolves about a point fixed to base  106 , and causes distal end of connector, link  108  to translate about a circular path. At the opposite distal end of connector link  108  is rotatably secured rocker link  110  as rocker link  110  oscillates about a point fixed to base  112 . The elliptical path  114  may be defined at a point directly between the opposite distal ends of connector link  108 . 
     Directing attention now with FIG. 4, a linkage system characteristic of the first embodiment is shown. The operator will stand with one foot on the first foot platform  126 , and with the opposite foot on the second foot platform while treading them about the elliptical path  134 . If the foot platforms are to remain level throughout the cyclic action, they must be able to pivot a total range of approximately 38 degrees relative to the connector links, or  19  degrees from a neutral position relative to the connector link. It may be preferable to incorporate rotational stops at the pin joint connecting each of the foot platforms limiting the rotational freedom to a total of 38 degrees in order to facilitate operation. 
     First crank radius  116  and first rocker link  124  are rotatably secured to the machine frame  130 , and also rotatably secured to first connector link  122 . Second crank radius  118  is rigidly fixed to and symmetrically opposite first crank radius  116 . Handle grips  132  are fixed to the machine frame  130  as a safety aid. Pulley  120  is nonrotatably secured to the first and/or second cranks  116  and  118  respectively and will transmit torque to and from flywheel  128 . Additionally, although not illustrated in any of the figures, drag resistance may be incorporated at the machine in any of the embodiments, by installing a band brake upon the flywheel, or hydraulic linear dampers or rotational dampers at any of the dynamic links. 
     Concluding on FIG. 4, datum lines  125  shown in broken lines illustrates the effective connector link  122  shape, and compares with link mechanism shown in FIG. 3 a.  Note that by establishing a segment line between the connector link foot platform journal (first third connector link joint) to the connector link rocker journal (first second connector link joint), followed by establishing a perpendicular line to the connector link crank journal (first first connector link joint), the perpendicular line will intersect the segment line between the segment line endpoints. 
     Directing attention now to FIG. 5, the linkage system of the first embodiment is shown with an independent means to maintain the foot platforms  136  and  138  parallel and horizontal. Crank radius  145  is rotatably secured to first and second connector link  144  and  140 , and revolves about a fixed point on the machine frame  148 . First and second rocker  146  and  142  share a common axis of rotation to the machine frame, and are connected at their opposite ends to first and second connector links  144  and  140  respectively. The platforms are maintained parallel by the geometrical relationships between the pair of identical orientations members  150 , the eight identical rigid bars  152 , and the constant pin joint hole patterns on the orientation members  150  and at the machine frame  148 . The datum lines  147  also compare with FIG. 3 a  of the first embodiment. 
     Referring now to FIG. 6, the linkage configuration of the first embodiment is shown in duality in order to provide a means to maintain the first and second foot platform  154  and  174  parallel and horizontal. The first foot platform  154  is rotatably secured at a first first foot platform joint  158  and at a third first foot platform joint  156  to a first connector link  162  and third connector link  160  respectively. Four rocker joints are also shown, with each pair of identically orientated rockers corresponding to one of the two foot platforms. In this embodiment (and also that of FIG.  2 ), the rockers pivot about a point fixed on the machine frame  178  for a total range of approximately thirty six degrees. The first rocker link  166  and third rocker link  164  have pivoted within eleven degrees of their forward most position while the connected platform is approximately at the apex of its travel. The relative positions between the rotation axes of first crank radius  170  and third crank radius  168  are identical to the relative positions between the axes of rotation of the pin joints present at each of the two foot platforms. 
     In order to give the machine inertial characteristics, a flywheel drive pulley  172  is fixed to one of the cranks wherein the drive pulley  172  rotational axis is co-axial with the associated crank rotational axis. 
     Referring now to FIG. 7, a perspective view is shown of the dual linkage mechanism shown in FIG. 6 corresponding to the first embodiment. First connector link  184  and third connector link  186  are rotatably secured at first foot platform  182  left and right sides, or first first foot platform joint  193  and third first foot platform joint respectively. The first connector link  184  is rotatably secured to first crank radius  194 . First crank radius  194  is rigidly connected to second crank radius  200  at crank axle  198 . Both cranks have a crank radius established diametrically opposite. Crank axle is supported at each side of crank pulley  185  by crank support plate  183 . If desired, the crank pulley could be secured to rotate with any of the four cranks: first crank radius  194 , second crank radius  200 , third crank radius  196 , or fourth crank radius  181 . Continuing with the illustrated pulley  185 , the crank support plates  183  are stationary with the machine frame. Flywheel pulley  189  is attached to flywheel shaft  191  and is driven via flywheel belt  187 . Second foot platform  202  second motion path  197  lies in a plane parallel to the first motion path  195  of first foot platform  182 . The first foot platform  182  is shown approximately at its uppermost position, and second foot platform  202  is shown approximately at its lowermost position. First crank radius  194  is of the same crank length as all other crank lengths. The dual linkage mechanism is secured to the stationary machine frame at a total of eight separate points, and four distinct rotational axis. First rocker link  190  and third rocker link  188  are orientated identically, and are rotatably secured to stationary base points symmetrical with their left side counterparts. Fourth rocker link  203  is rotatably connected to fourth connector link, and fourth connector link is rotatably connected to second second foot platform joint  199 . Second first foot platform joint is directed into the paper, and is not visible in this figure. 
     Directing attention now to FIG. 8, a singular first foot platform  204  is designed of proper width as to receive both feet of the user. The linkage mechanism is of a similar design of the first embodiment. The operator may power this mechanism while in a semi-reclined position, and pump the singular first foot platform  204  in a motion similar to what would be experienced when performing knee bends or standing/squatting exercises. The pad that the operator is resting upon shall preferably be inclined ten or twenty degrees. Third crank radius  208  is rotatably secured to both the unillustrated machine frame and to third connector link  206 . Third connector link distal end  212  is rotatably secured to third rocker link  210 . First rocker link  214  is rotatably secured to the machine frame at pin joint  216 , and also to first connecter link  218 . The foot platform will translate about a first path  205  while maintaining constant angular orientation with respect to the machine frame. Crank shaft  222  is rotatable secured to the machine frame and supports both the first crank radius  220  and a flywheel drive pulley  224 . The flywheel  226  is driven by flywheel drive pulley  228  via flywheel endless drive member  227 . The flywheel endless member may be a standard V-belt, a timing belt or synchronous belt, a flat or round belt, or a roller chain. A flywheel is particularly desirable in this version of the first embodiment because the momentum of the flywheel  226  may be necessary to power the foot platform during return motion toward the operator. Shown also in this figure is a compression spring  211  to always return and park the first foot platform  204  toward the operator past both cranks top dead center position when the exercise machine is idle. This will bias the mechanism to a starting position and enable the foot platform to readily move in the correct direction upon machine startup during applied foot compression force against first foot platform  204 . This compression spring  211  need have only a relatively low spring constant to serve this function, although if distinct and adjustable force characteristics are desired to be incorporated, the spring constant could be increased appreciably such that a flywheel need not be present. In this regard, a spring of significant constant may be present; particularly on embodiments which do not have the foot platforms coupled together at a common crank axis (platforms may be cycled independently) in order to supplement or replace the flywheel. The spring may be secured at one end to the machine frame, and at the opposite end to any suitable anchor point upon the mechanism including one or more of the cranks, rockers, connector links, or even upon the foot platforms. For example, if a spring is incorporated into the linkage on FIG. 7 to assure return of the foot platforms, then the cranks  194  and  200  would not need to be physically connected. 
     It may be noted that reference is made of ‘first’ and ‘third’ members in FIG. 7 in order to be consistent with the text. In this respect, text reference to ‘first’ and ‘third’ always corresponds to the first foot platform, and text reference to ‘second’ and ‘fourth’ always corresponds to the second foot platform, if the referenced members exist in the figure. Also, although this figure shows ‘third’ members, it would still function well if only ‘first’ members were present, properly resulting in a foot platform mounted rotatably to the connector link. This foot platform would then function much like one oversized bicycle pedal. 
     Referring now to FIG. 9, datum lines  254  indicate a linkage arrangement corresponding to FIG. 3 a  of the first embodiment. First rocker joint  246  and second rocker joint  248  are rotatably secured to machine frame  250  at a common axis. First connector link  232  and second connector link  234  are rotatably secured to first crank radius  236  and second crank radius  238 . First and second cranks  236  and  238  have collinear rotational axes  240  about a point stationary with the machine frame  242 . The reader will note that on all of the embodiments illustrated, the paired first and second and/or third and fourth cranks revolve, and are represented as rigid members sharing a one axis of rotation. These revolving cranks may therefore be replaced by a disk, wheel, or even a flywheel with pin joints established at diametrically opposite positions if dimensional mounting constraints allow. The elliptical path  230  of the unillustrated foot platforms is situated to be readily engageable with the operators feet when the operator is positioned in seat  252 . 
     Directing attention now to FIG. 10, a closed curve is shown which will produce a motion at the foot platforms which represents an ellipse of relatively sharp proportions. The datum lines  278  are characteristic of the mechanism shown in FIG. 3 b  of the second embodiment. The linkage mechanism may be operated while one is standing. First and second foot platforms  256  and  266  respectively may be rigid with first and second connector links  258  and  259  respectively. First cranks radius  262  and second crank radius  274  are rotatably secured at rotational joint  264  attached to machine frame  276 . Corresponding to the first connector link, pin joint  260  allows full rotation of first connector link  258  relative to first crank radius  262 . First rocker link  270  and second rocker link  272  are rotatably attached to first and second connector links  258  and  259  respectively, and are also rotatably secured to machine frame  282  while sharing a common rotational axis. 
     Referring now to FIG. 11, a linkage mechanism is shown with datum lines  301  indicating an arrangement similar to FIG. 3 b.  Foot platforms are rotatably secured to first and second connector links  292  and  290  at bearings  288  and  286  respectively. First and second rocker joints  296  and  294  share a common rocker rotational axis  298  at a portion of the machine frame  300 . Crank  306  has pin joints symmetrically opposite each side of crank rotation axis  302 . Crank rotational axis does not translate with respect to machine frame  304 . In this embodiment the operator will be positioned in seat  308  and crank the unillustrated foot pedals along the illustrated elliptical path  284 . 
     Note that in this embodiment, first and second connector links  292  and  290  may have attached handle bars  297  and  295  respectively which may be moved throughout a closed handle bar curve  299  generated at the handle bar attachment point. In this configuration, the user cyclically forces the foot platforms throughout their elliptical path while simultaneously exercises the upper body by forcing the handle bar throughout its elliptical path  299  during the use of ones&#39; arms and hands. By attaching the handles closer to the rocker joints than the attachment point of the foot platforms are to the rocker joints, the closed curve path  299  generated at the handle bar is relatively smaller than the closed curve path  284  generated at the foot platforms. An upper and lower body exercise machine such as this would be operated by alternatingly pushing with ones feet and pulling with ones arms. In describing this motion, as the operator faces the machine and the two somewhat horizontal elliptical paths, the operator will pull with his/her right arm at the lower region of the handle bar path  299  while freely returning his right foot at the lower portion of the right foot pedal path  284 , followed by returning his/her right hand forward at the upper half of the handle bar path  299  and pushing his/her right foot at the upper half of the foot pedal path  284 . The left side of the operators body would be out of phase with the right side by 180 degrees. 
     If both feet are placed upon one platform, and only one crank, rocker, and connector link exists on the machine, the exercise machine has operational characteristics unique to the exercise industry. An upper and lower body exercise machine such as this would be operated by alternatingly pushing both feet and pulling with both arms. In describing this motion, as the operator faces the machine and the two horizontal elliptical paths, the operator will pull with both arms at the lower region of the top ellipse while freely returning both feet at the lower portion of the bottom ellipse. This action will be followed by returning both hands forward at the upper half of the top ellipse while pushing both feet at the upper half of the bottom ellipse. This action is not to be confused with a rowing machine action for the following three reasons: (1) the upper body and the lower body is exercised at a phase difference of 180 degrees, as opposed to the rowing machine which stresses both the upper and lower body simultaneously; (2) most rowing machines do not include a flywheel; and (3) continuous cyclical motion exists with the present invention as opposed to the stop and go or continuously reversing action of a rowing machine. 
     Continuing now with FIG. 12, a third embodiment is shown with datum lines  336  similar to both FIG. 3 c  and FIG. 3 d.  In these figures, if a segment line is established between the connector link crank journal (first first connector link joint) to the connector link foot platform journal (first third connector link joint), and then a perpendicular line is drawn passing through the connector link rocker journal (first second connector link joint), the perpendicular line will intersect the segment line between the segment line endpoints. 
     As further shown on FIG. 12, the proximity of the crankshaft  324  enables the operator to stand while optionally rotating the handle grips  326  of crank  322  by hand. Crank  322  is rigid between the rotational axis of the upper distal ends of first connector link  320  and second connector link  330 , and rotatably secures the upper distal ends of the connector links as they revolve about the crank rotational axis. First and second rocker links  318  and  316  share a common rotational axis fixed to the machine frame  315  thereby allowing the required pivoting or oscillating motion. First and second foot platform  312  and  310  respectively travel along the now familiar elliptical path  314  during crank rotation. Crank pulley  328  may be of sufficient size and mass as to adequately serve as a flywheel, or may drive a flywheel  332  rotatably secured to the machine frame  315 . 
     Directing attention now to FIG. 13, datum lines  350  depict a linkage system similar to FIG. 3 c.  This is another arrangement of linkages which allows the operator to be seated while exercising both the upper and lower body, without the necessity of additional mechanical elements such as pulleys or actuators to bring working curves within proximity of both the upper and lower body. Crank  342  rotates about a point fixed to machine frame  344 , and connects at opposite crank radii to first and second connector links  341  and  340 . First and second rockers  338  and  346  pivot about a point fixed to the machine frame  348 , and are physically placed at each side of the operator as to not interfere with the operators leg motion. Elliptical path  352  is generated at pin joints  336  and  337 . 
     When the operator is positioned in seat  354 , both the foot pedals and the hand grips may be adjusted to fit the operator properly. This may be accomplished by changing the distance between the machine frame and the seat  354 , and/or changing the orientation and/or shape of the elliptical path(s). To change the orientation or angle between the major axis of the elliptical path relative to a horizontal plane, simply rotate the machine frame including portions  344  and  348  about which the cranks and rockers are rotatably secured. To change the shape of the elliptical path, two of the simplest methods is to change the distance between the two machine frame regions  344  and  348  resulting in a new centerline distance between the machine frame secured rotational axes of the cranks and rockers, or alternatively adjust and change the length of any or all of the three dynamic links (cranks, connector links, and rockers). 
     Referring finally now to FIG. 14, datum lines  382  most closely represent the linkage mechanism of FIG. 3 a.  Crank  370  revolves about a point fixed to the machine frame  372 , and rotatably secures first and second proximate connector link regions  366  and  368 . First and second rocker links  376  and  374  pivot about a point fixed relative to a portion of machine frame  378 . First and second connector links  364  and  362  are rotatably secured to the crank  370  and to first and second rocker  376  and  374 . The operators feet may exert force directly on perpendicular shafts  360  and  358 , or upon unillustrated rotatable foot pedals rotatably joined at shafts  360  and  358 . The operator seat  380  may be positions for optimum comfort while cycling his/her feet along the elliptical path  356 . Again, as with all embodiments, the elliptical path may also be customized to preferences of the operator. 
     Thus, an improved exercise machine is shown which provides the operator with motions or combinations of motions which are new in the art. While preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims.