Elliptical exerciser

Abstract

An elliptical exerciser comprising a frame, a crank assembly providing a crank axis fixed with respect to frame above the horizontal surface, crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from crank axis, left and right pedal members having rear portions connected with left and right cranks respectively, left and right rollers mounted on frame for rotation about a single rolling axis parallel with respect to crank axis in a forward position above the horizontal surface a distance less than the distance of crank axis above horizontal surface, left and right pedal members having straight downwardly facing surfaces rollingly supported on left and right rollers respectively, left and right pedal members providing left and right foot supporting structures of improved construction enabling a user to impart cyclical movements to the pedal members resisted by a variable resistance assembly, each cyclical movement including (1) a downward moving stroke wherein the ball of the user's foot moves forwardly along a first curved path merging into a relatively small generally arcuate end path and from generally arcuate forward end path rearwardly along a second curved path symmetrical to first path with respect to an axis of symmetry and (2) an upward return stroke wherein the ball of the user's foot moves rearwardly from second path rearwardly along a third curved path different from second path merging into a relatively large generally arcuate rearward end path and from generally arcuate rearward end path forwardly along a fourth curved path symmetrical to first path with respect to the aforesaid axis of symmetry, axis of symmetry extending downwardly and forwardly and having an extent between end paths which is generally equal to the distance between the parallel rotational axis provided by cranks and at least three times greater than the extent from a juncture between fourth and first curved paths to a juncture between third and second paths, the distance between crank axis and rolling axis, being at least three times greater than the distance between the parallel rotational axes provided by cranks.

1 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a rearward position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced approximately 180° with respect to one another,    left and right pedal members having rear portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a single rolling axis parallel with respect to said crank axis in a forward position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at forward end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    each crank having a crank radius within an operative range of between 6″ and 14″,    said crank axis being spaced above said horizontal surface within an operative range of between 15″ and 23″,    said rolling axis being spaced horizontally forwardly from the crank axis within an operative range of between 52.25″ and 68.25,″ and spaced vertically downwardly from the crank axis within an operative range of between 8.375″ and 16.375.″   
     
     
         2 . An elliptical exerciser as defined in  claim 1 , wherein said rollers are of equal radius within an operative range of 0.125″ and 3.0″, the forward distance from each rearward rotational axis to the fixed position on the upwardly facing surface of the respective pedal member where the ball of the foot is supported being greater than one half the length of the respective pedal member and within an operative range of between 36.25″ and 44.25″.  
     
     
         3 . An elliptical exerciser as defined in  claim 2 , wherein each cyclical movement includes (1) a downward moving stroke wherein the ball of the user's foot moves forwardly along a first curved path merging into a relatively small generally arcuate end path and from said generally arcuate forward end path rearwardly along a second curved path symmetrical to said first path with respect to an axis of symmetry and (2) an upward return stroke wherein the ball of the user's foot moves rearwardly from said second path rearwardly along a third curved path different from said second path merging into a relatively large generally arcuate rearward end path and from said generally arcuate rearward end path forwardly along a fourth curved path symmetrical to said third path with respect to the aforesaid axis of symmetry, 
 said axis of symmetry extending downwardly and forwardly and having a length between said end paths which is generally equal to the distance between the parallel rotational axes provided by said cranks and at least three times greater than the width from a juncture between said fourth and first curved paths to a juncture between said third and second curved paths, the distance between said crank axis and said rolling axis being at least three times greater than the distance between the parallel rotational axes provided by said cranks.    
     
     
         4 . An elliptical exerciser as defined in  claim 3 , wherein said selectively variable resistance assembly is driven by said crank assembly and is housed within a casing, said left and right foot supporting structures being disposed forwardly of said casing throughout the movements thereof and spaced laterally apart an optimum distance.  
     
     
         5 . An elliptical exerciser as defined in  claim 4 , wherein said frame inc forward frame portion defining said rolling axis thereon and a separate rearward frame portion defining said crank axis thereon, said frame portions being mounted with respect to another for selective movement into one of a series of fixed operative positions wherein the horizontal distance between said crank axis and said rolling axis is disposed at a selected distance within a range of different distances.  
     
     
         6 . An elliptical exerciser as defined in  claim 5 , wherein each foot supporting structure includes upstanding barrier structure configured to prevent the users foot from moving forwardly with respect to the respective upwardly facing surface when in a toe engaging operative position, each upstanding barrier structure being mounted on the respective pedal member for selective movement with respect to the respective upwardly facing surface into a selected toe engaging operative position within a range of toe engaging operative positions spaced different distances from the respective parallel rotational axis.  
     
     
         7 . An elliptical exerciser as defined in  claim 6 , wherein each upstanding barrier structure is mounted for movement into an oppositely facing longitudinally spaced heel engaging position.  
     
     
         8 . An elliptical exerciser as defined in  claim 7 , wherein said left and right pedal members have left and right handle levers respectively associated therewith, said left and right hand levers having (1) upper end portions defining left and right handles respectively to be gripped by left and right hands respectively of a user, (2) mid-portions pivotally mounted on said frame about a common transverse pivotal axis, and (3) lower portions disposed below said mid-portions, and left and right connecting links pivoted at forward ends thereof to the lower portions of said left and right handle levers respectively and at rearward ends thereof to intermediate portions of said left and right pedal members respectively.  
     
     
         9 . An elliptical exerciser as defined in  claim 4 , wherein said left and right foot supporting structures include inner foot retaining walls, the lateral spacing of said left and right foot supporting structures being approximately 60 mm between said inner walls.  
     
     
         10 . An elliptical exerciser as defined in  claim 9 , wherein said optimum lateral spacing is less than the widest lateral dimension of said casing.  
     
     
         11 . An elliptical exerciser as defined in  claim 10 , wherein the lateral space between said foot supporting structures is devoid of interfering structure in any position of movement of said pedal members.  
     
     
         12 . An elliptical exerciser as defined in  claim 2 , wherein said rollers have a radius within a preferred range of 0.31″ and 1.30″, the forward distance from each rearward rotational axis to the fixed position on the upwardly facing surface of the respective pedal member where the ball of the foot is supported being within a preferred range of between 38.25″ and 42.25″.  
     
     
         13 . An elliptical exerciser as defined in  claim 12 , wherein said rollers have a radius of approximately 0.81″, the forward distance from each rearward rotational axis to the fixed position on the upwardly facing surface of the respective pedal member where the ball of the foot is supported being approximately 40.25″.  
     
     
         14 . An elliptical exerciser as defined in  claim 1 , wherein each crank has a crank radius within a preferred range of between 8″ and 12″, said crank axis being spaced above said horizontal surface within a preferred range of between 17″ and 21″, said rolling axis being spaced horizontally forwardly from the crank axis within a preferred range of between 56.25″ and 64.25″ and spaced vertically downwardly from the crank axis within a preferred range of between 10.375″ and 14.375″.  
     
     
         15 . An elliptical exerciser as defined in  claim 14 , wherein each crank has a crank radius of approximately 10″, said crank axis being spaced above said horizontal surface approximately 19.7″, said rolling axis being spaced horizontally. forwardly from the crank axis approximately 60.25″ and spaced vertically downwardly from the crank axis approximately 12.375″.  
     
     
         16 . An elliptical exerciser as defined in  claim 1 , wherein said frame includes a forward frame portion defining said rolling axis thereon and a separate rearward frame portion defining said crank axis thereon, said frame portions being mounted with respect to another for selective movement into one of a series of operative positions wherein the horizontal distance between said crank axis and said rolling axis is disposed at a selected distance within a range of different distances.  
     
     
         17 . An elliptical exerciser as defined in  claim 16 , wherein said forward and rearward frame portions are telescopically interrelated.  
     
     
         18 . An elliptical exerciser as defined in  claim 1 , wherein each foot supporting structure includes upstanding barrier structure configured to prevent the users foot from moving forwardly with respect to the respective upwardly facing surface when in a toe engaging operative position, each upstanding barrier structure being mounted on the respective pedal member for selective movement with respect to the respective upwardly facing surface into a selected toe engaging operative position within a range of toe engaging operative positions spaced different distances from the respective parallel rotational axis.  
     
     
         19 . An elliptical exerciser as defined in  claim 18 , wherein each upstanding barrier structure is mounted for movement with respect to the associated upwardly facing surface into an oppositely facing heel engaging position.  
     
     
         20 . An elliptical exerciser as defined in  claim 19 , wherein each foot engaging structure includes a platform defining the respective upwardly facing surface.  
     
     
         21 . An elliptical exerciser as defined in  claim 20 , wherein each platform has a periphery open at an outer side with an upstanding structure extending throughout the remainder thereof.  
     
     
         22 . An elliptical exerciser as defined in  claim 21 , wherein each platform is formed with a longitudinal slot extending through the respective upwardly facing surface and a series of longitudinally spaced downwardly facing teeth on opposite sides of said slot, each upstanding barrier structure comprising a barrier assembly including a curved upper barrier member extending on opposite sides of said slot above the respective upwardly facing surface and having a portion slidable in said slot, a central fastener member slidably mounted in said upper barrier member and extending downwardly therefrom through said slot, a lower member extending on opposite sides of said slot connected with said fastener member, said lower member including a series of longitudinally spaced upwardly facing teeth configured to interengage with said downwardly facing teeth to establish the fixed relationship, a pusher member fixed to an upper end of said fastener member above said barrier member and a spring acting between said pusher member and said barrier member so as to resiliently bias the teeth of said lower member upwardly into interengaging relation with the teeth of said platform and the lower portion of said barrier member into confined sliding relation within said slot, said spring bias enabling: (1) a combined downward manual push and longitudinal movement on said pusher member to effect longitudinal movement of said barrier member with the lower portion thereof in sliding relation to said slot and the teeth of said lower member disengaged from the teeth of said platform, and (2) a combined vertical and rotational movement of said barrier member to effect rotational movement of the barrier member into and out of the 180° turned positioning thereof.  
     
     
         23 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a rearward position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced approximately 180° with respect to one another,    left and right pedal members having rear portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a forward position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at forward end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    each cyclical movement including (1) a downward moving stroke wherein the ball of the user's foot moves forwardly along a first curved path merging into a relatively small generally arcuate end path and from said generally arcuate forward end path rearwardly along a second curved path symmetrical to said first path with respect to an axis of symmetry and (2) an upward return stroke wherein the ball of the user's foot moves rearwardly from said second path rearwardly along a third curved path different from said second path merging into a relatively large generally arcuate rearward end path and from said generally arcuate rearward end path forwardly along a fourth curved path symmetrical to said third path with respect to the aforesaid axis of symmetry,    said axis of symmetry extending downwardly and forwardly and having a length between said end paths which is generally equal to the distance between the parallel rotational axes provided by said cranks and at least three times greater than the width from a juncture between said fourth and first curved paths to a juncture between said third and second paths, the distance between said crank axis and said rolling axis, being at least three times greater than the distance between the parallel rotational axes provided by said cranks.    
     
     
         24 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a rearward position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced approximately 180° with respect to one another,    left and right pedal members having rear portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a forward position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at forward end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly driven by said crank assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    a casing housing said variable resistance assembly    said left and right foot supporting structures being disposed forwardly of said casing throughout the movements thereof and spaced laterally apart an optimum distance.    
     
     
         25 . An elliptical exerciser as defined in  claim 24 , wherein said left and right foot supporting structures include inner foot retaining walls, the lateral spacing of said left and right foot supporting structures being approximately 60 mm between said inner walls.  
     
     
         26 . An elliptical exerciser as defined in  claim 25 , wherein said optimum lateral spacing is less than the widest lateral dimension of said casing.  
     
     
         27 . An elliptical exerciser as defined in  claim 26 , wherein the lateral space between said foot supporting structures is devoid of interfering structure in any position of movement of said pedal members.  
     
     
         28 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced approximately 180° with respect to one another,    left and right pedal members having first end portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at second end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    said frame including a forward frame portion defining said rolling axis thereon and a separate rearward frame portion defining said crank axis thereon, said frame portions being mounted with respect to another for selective movement into one of a series of operative positions wherein the horizontal distance between said crank axis and said rolling axis is disposed at a selected distance within a range of different distances.    
     
     
         29 . An elliptical exerciser as defined in  claim 28 , wherein said forward and rearward frame portions are telescopically interrelated.  
     
     
         30 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced approximately 180° with respect to one another,    left and right pedal members having first portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at second end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    said left and right pedal member have left and right handle levers respectively associated therewith, said left and right hand levers having (1) upper handle portions respectively to be gripped by left and right hands respectively of a user, (2) mid-portions pivotally mounted on said frame about a common transverse pivotal axis, and (3) lower portions disposed below said mid-portions, and left and right connecting links pivoted at forward ends thereof to the lower portions of said left and right handle levers respectively and at rearward ends thereof to intermediate portions of said left and right pedal members respectively.    
     
     
         31 . An elliptical exerciser as defined in  claim 30 , wherein each connecting link is selectively adjustably pivoted to the lower end portion of the respective handle lever and to the respective pedal member so as to selectively vary the fore and aft position of movement of the respective handle portion.  
     
     
         32 . An exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface;    an exercising mechanism on said frame including left and right pedal assemblies constructed and arranged to enable a user to apply thereto repeated generally elliptical cyclical movements providing exercise to the user;    each of said pedal assemblies including a generally upwardly facing foot supporting surface and an upstanding barrier structure constructed and arranged when in a toe engaging operative position to be engaged by a toe area of a user to prevent forward movement of the users foot therebeyond;    said barrier structure being incorporated within the respective pedal assembly so as to be selectively movable with respect to the respective foot supporting surface into a selected toe engaging operative position within a range of toe engaging operative positions.    
     
     
         33 . An exerciser as defined in  claim 32 , wherein said exercising mechanism includes a rearward crank mounting assembly and a forward mounting assembly for said left and right pedal assemblies constructed and arranged to cause said left and right pedal assemblies to undergo repeated generally elliptical cyclical movements.  
     
     
         34 . An exerciser as defined in  claim 33 , wherein said crank mounting assembly provides a crank axis fixed with respect to said frame in a rearward position above the horizontal surface, said crank mounting assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced 180° with respect to one another, said left and right pedal members having rear portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof, 
 said forward mounting assembly comprising left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a forward position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface, said left and right pedal members having straight downwardly facing surfaces at forward end portions thereof rollingly supported on said left and right rollers respectively, and a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members.    
     
     
         35 . An exercise as defined in  claim 34 , wherein each cyclical movement includes: (1) a downward moving stroke wherein the ball of the user's foot moves forwardly along a first curved path merging into a relatively small generally arcuate end path and from said generally arcuate forward end path rearwardly along a second curved path symmetrical to said first path with respect to an axis of symmetry and (2) an upward return stroke wherein the ball of the user's foot moves rearwardly from said second path rearwardly along a third curved path different from said second path merging into a relatively large generally arcuate rearward end path and from said generally arcuate rearward end path forwardly along a fourth curved path symmetrical to said third path with respect to the aforesaid axis of symmetry.  
     
     
         36 . An exerciser as defined in  claim 32 , wherein each of said barrier structures is incorporated within the respective pedal assembly for combined 180° rotational and longitudinal movements into a rearward heel engaging operative position wherein the barrier structure is operable to be engaged by a heel area of a users foot to prevent rearward movement therebeyond.  
     
     
         37 . An exerciser as defined in  claim 36 , wherein each foot engaging structure includes a platform having a periphery open at an outer side thereof and having structure extending upwardly along a remaining portion of the periphery thereof including an inner side thereof.  
     
     
         38 . An exerciser as defined in  claim 37 , wherein each peripheral structure extends continuously from the inner side thereof upwardly along front and rear ends of the periphery of each platform.  
     
     
         39 . An exerciser as defined in  claim 38 , wherein each platform is formed with a longitudinal slot and a series of longitudinally spaced downwardly facing teeth on opposite sides of said slot, each upstanding barrier structure comprising a barrier assembly including a curved upper barrier member extending on opposite sides of said slot and having a portion slidable in said slot, a central fastener member slidably mounted in said upper barrier member and extending downwardly therefrom through said slot, a lower member extending on opposite sides of said slot connected with said fastener member, said lower member including a series of longitudinally spaced upwardly facing teeth configured to interengage with said downwardly facing teeth to establish said retained relationship, a pusher member fixed to an upper end of said fastener member above said barrier member and a spring acting between said pusher member and said barrier member so as to resiliently bias the teeth of said lower member upwardly into interengaging relation with the teeth of said platform and the lower portion of said barrier member into confined sliding relation within said slot, said spring bias enabling: (1) a combined downward manual push and longitudinal movement on said pusher member to effect longitudinal movement of said barrier member with the lower portion thereof in sliding relation to said slot and the teeth of said lower member disengaged from the teeth of said platform, and (2) a combined vertical and rotational movement of said barrier member to effect rotational movement of the barrier member into and out of oppositely facing positioning thereof.  
     
     
         40 . An exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface;    an exercising mechanism on said frame including left and right pedal assemblies constructed and arranged to enable a user to apply thereto repeated generally elliptical cyclical movements providing exercise to the user;    each of said pedal assemblies including a generally upwardly facing foot supporting surface and an upstanding barrier structure constructed and arranged in a forward position to be forwardly engaged by a toe area of a user and in a rearward position to be rearwardly engaged by a heel area of a user, each barrier structure being incorporated within the respective pedal assembly so as to be movable between said forward and rearward positions by a combination of 180° rotational and longitudinal movements.    
     
     
         41 . An exerciser as defined in  claim 40 , wherein each foot engaging structure includes a platform having a periphery open at an outer side thereof and having structure extending upwardly along a remaining portion of the periphery thereof including an inner side thereof.  
     
     
         42 . An exerciser as defined in  claim 41 , wherein each peripheral structure extends continuously from the inner side thereof upwardly along front and rear ends of the periphery of each platform.  
     
     
         43 . An exerciser as defined in  claim 42 , wherein each platform is formed with a longitudinal slot and a series of longitudinally spaced downwardly facing teeth on opposite sides of said slot, each upstanding barrier structure comprising a barrier assembly including a curved upper barrier member extending on opposite sides of said slot and having a portion slidable in said slot, a central fastener member slidably mounted in said upper barrier member and extending downwardly therefrom through said slot, a lower member extending on opposite sides of said slot connected with said fastener member, said lower member including a series of longitudinally spaced upwardly facing teeth configured to interengage with said downwardly facing teeth to establish said retained relationship, a pusher member fixed to an upper end of said fastener member above said barrier member and a spring acting between said pusher member and said barrier member so as to resiliently bias the teeth of said lower member upwardly into interengaging relation with the teeth of said platform and the lower portion of said barrier member into confined sliding relation within said slot, said spring bias enabling: (1) a combined downward manual push and longitudinal movement on said pusher member to effect longitudinal movement of said barrier member with the lower portion thereof in sliding relation to said slot and the teeth of said lower member disengaged from the teeth of said platform, and (2) a combined vertical and rotational movement of said barrier member to effect rotational movement of the barrier member into and out of oppositely facing positioning thereof.  
     
     
         44 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced about 180° with respect to one another,    left and right pedal members having first end portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at second end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    each of said downwardly facing surfaces including laterally spaced planar portions having a differently shaped intermediate portion therebetween,    each of said rollers including laterally spaced cylindrical surfaces rollingly mating with the laterally spaced planar surfaces of a respective downwardly facing surface and a differently shaped intermediate portion therebetween rollingly mating with the differently shaped intermediate portion of a respective downwardly facing surface,    said differently shaped intermediate portions including projections and recesses.    
     
     
         45 . An elliptical exerciser as defined in  claim 44 , wherein the cross-sectional configuration of each projection and cooperating recess is of arcuate shape.  
     
     
         46 . An elliptical exerciser as defined in  claim 45 , wherein the cross-sectional configuration of each projection and cooperating recess is of rectangular shape.  
     
     
         47 . An elliptical exerciser as defined in  claim 46 , wherein each projection and cooperating recess comprises parallel projections and cooperating parallel recesses.  
     
     
         48 . An elliptical exerciser as defined in  claim 44 , wherein said projections are formed as elongated intermediate portions of said downwardly facing surfaces and said recesses are formed as annular intermediate portions of said rollers.  
     
     
         49 . An elliptical exerciser as defined in  claim 44 , wherein said projections are formed as annular intermediate portions of said rollers and said recesses are formed as elongated intermediate portions of said downwardly facing surfaces.  
     
     
         50 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a rearward position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced about 180° with respect to one another,    left and right pedal members having first end portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at second end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    said downwardly facing surfaces being planar intermediate horizontal surfaces having vertical surfaces on opposite sides thereof,    said rollers including rollers rollingly contacting said horizontal surfaces and rollers rollingly contacting said vertical surfaces.    
     
     
         51 . An elliptical exerciser as defined in  claim 50 , wherein said vertical surfaces face toward one another.  
     
     
         52 . An elliptical exerciser as defined in  claim 50 , wherein said vertical surfaces face away from one another.  
     
     
         53 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced about 180° with respect to one another,    left and right pedal members having first end portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at second end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    said downwardly facing surfaces including side portions extending downwardly and inwardly toward a lower central portion, said rollers including a roller rollingly engaging each of said side portions.    
     
     
         54 . An elliptical exerciser as defined in  claim 53 , wherein said side portions are convexly arcuate in cross-section.  
     
     
         55 . An elliptical exerciser as defined in  claim 53 , wherein said side portions are straight in cross-section.  
     
     
         56 . An elliptical exerciser comprising: 
 a frame constructed and arranged to be stably supported on a horizontal surface,    a crank assembly providing a crank axis fixed with respect to said frame in a position above the horizontal surface,    said crank assembly including oppositely extending left and right cranks providing parallel rotational axis spaced equidistantly from said crank axis and displaced about 180° with respect to one another,    left and right pedal members having first end portions connected with said left and right cranks respectively for rotational movement about the respective rotational axis thereof,    left and right rollers mounted on said frame for rotation about a rolling axis parallel with respect to said crank axis in a position above the horizontal surface a distance less than the distance of said crank axis above said horizontal surface,    said left and right pedal members having generally downwardly facing surfaces at second end portions thereof rollingly supported on said left and right rollers respectively,    said left and right pedal members providing left and right foot supporting structures defining generally upwardly facing surfaces between the forward and rearward ends of said pedal members, each being in an operatively fixed position with respect to the respective pedal member to support the ball of a user's foot so as to enable a user to apply repeated generally elliptical cyclical movements to said left and right pedal members, and    a selectively variable resistance assembly constructed and arranged to provide a selected resistance within a range of resistances to the cyclical movements of said left and right pedal members,    each of said pedal members being formed as a tube,    each respective downwardly facing surfaces comprising an arcuate segment of a cylindrical periphery of a tube,    said arcuate segments having roller surfaces in rolling engagement therewith.    
     
     
         57 . An elliptical exerciser as defined in  claim 56 , wherein each arcuate segment has a pair of rollers with perpendicular roller axes in rolling engagement therewith.  
     
     
         58 . An elliptical exerciser as defined in  claim 56 , wherein each roller in rolling engagement with an arcuate segment has a grooved peripheral surface rollingly mating therewith.  
     
     
         59 . An elliptical exerciser as defined in  claim 24 , wherein said casing is a housing having open sides to accommodate the movement of said left and right cranks, said open sides being substantially closed by disks which rotate about the crank axis by the movement of the cranks.  
     
     
         60 . An exerciser as defined in  claim 28 , wherein said frame includes rearwardly extending rollers on a rearward end thereof position to engage the floor when the forward end of the frame is tilted upwardly so as to render the frame rollingly portable.