Abstract:
A dual mode exercise machine which can work in a stepping mode, or in an elliptical mode, and which has an interlock mechanism which ensures that the machine cannot be placed in a condition in which neither mode is engaged.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to an aerobic exercise machine. 
         [0002]    Different types of machines exist for aerobic exercises and for muscle conditioning based on movement which is referred to, perhaps somewhat loosely, as elliptical. Some of these machines however offer only one exercise. The monotony of a single exercise can result in boredom and cause a user to discontinue the exercise. Also, repeated performance of one type of exercise is less effective than engaging in a variety of exercises. 
         [0003]    A few so-called “dual mode” exercise machines have been developed. These machines offer a second type of exercise in addition to exercise based on the so-called elliptical movement. Usually though this is at the cost of complex design and additional expenditure. A further aspect is that a somewhat laborious process is required when reconfiguring parts of the machine in order to change from one exercise mode to another. 
         [0004]    For example, a machine referred to as “SEG-1682—Two-in-one Elliptical and Stepper” (cf http://www.thane.com/service.php), has a footplate which is mounted to a slider. In a stepper mode the footplate is locked to a cross-member by means of a screw. Upon rotation of a crank the footplate is moved up and down in a vertical mode. 
         [0005]    A similar construction is embodied in a machine, also from SEG, labelled “ED-3060—Motorised Elliptical Tread”. To place the machine in an elliptical mode a screw is loosened and a footplate is moved along a slider to a defined position at which the slider is locked against movement. Rotation of a crank then causes the footplate to move in an elliptical fashion. The crank is permanently connected to the slider. 
         [0006]    A so-called “Street Bike” (origin unknown), (which is a mobile device and not a stationary exercise machine), includes a pedal mechanism wherein up/down movement imparted by a user to footpads is translated into rotational movement of a crank which has arms which are slidingly engaged with the footpads. This “Street Bike” offers only one mode of use. 
         [0007]    An object of the present invention is to provide a dual mode exercise machine which is relatively inexpensive and which has a simple construction to facilitate switching from a first exercise mode to a second exercise mode. An additional important aspect of the invention is that the exercise machine cannot readily be placed in a situation in which neither mode is engaged. This enhances the safety of use of the exercise machine. 
         [0008]    In this specification a first exercise mode is also referred to as a “stepping” mode. A second exercise mode results upon rotation of a crank around an axis. Movement is transferred from the crank via a footplate to a user. This movement may be circular or partly circular and, for the sake of convenience and in order to distinguish one mode from the other, is referred to as “elliptical” movement. 
       SUMMARY OF INVENTION 
       [0009]    The invention provides an exercise machine which includes ground-engaging support structure, a pedal arrangement which includes first and second crank members which are mounted to the support structure for rotational movement about a first axis, first and second handles which are mounted to the support structure for pivotal movement about a second axis, first and second cross members which are respectively pivotally connected to the first and second handles, first and second foot-engaging structures, mounted respectively to the first and second cross members, which are respectively engaged with, and which are movable relative to, the first and second crank members, first locking means operative to lock the first and second handles to the support structure thereby to inhibit pivotal movement of the handles about the second axis so that, upon rotational movement of the pedal arrangement, the first and second foot-engaging structures are movable to provide a first exercise action and, in response thereto, the first and second cross members are pivotally movable relative to the first and second handles, and second locking means operative to lock the first and second crank members to the first and second cross members respectively, so that, upon rotational movement of the pedal arrangement, the first and second foot-engaging structures are movable to provide a second exercise action and, in response thereto, the first and second handles are pivotally movable about the second axis. 
         [0010]    The first exercise action may be a stepping action and the second exercise action may be an elliptical action. 
         [0011]    Preferably the exercise machine includes a resistance device which acts at least against rotational movement of the pedal arrangement. 
         [0012]    The exercise machine may include first and second guides which respectively retain the first and second foot-engaging structures in engagement with the first and second crank members. 
         [0013]    Preferably the first and second locking means include an interlock mechanism which prevents the first and the second locking means from being rendered inoperative at the same time. 
         [0014]    The interlock mechanism may for example include an actuator which is engageable with the first locking means, when operative, and which is then actuable thereby to render the first locking means inoperative and which is only disengageable from the first locking means when the first locking means is operative, and which is engageable with the second locking means, when the second locking means is operative, and which is then operable to render the second locking means operative and which is only disengageable from the second locking means when the second locking means is operative. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The invention is further described by way of example with reference to the accompanying drawings in which: 
           [0016]      FIG. 1  is a side view of an exercise machine according to the invention in a first, stepper mode of operation; 
           [0017]      FIG. 2  shows the exercise machine of  FIG. 1  in a second, elliptical mode of operation; 
           [0018]      FIG. 3  shows part of the exercise machine in  FIG. 1  on an enlarged scale; 
           [0019]      FIG. 4  is a view in cross-section of the machine taken on a line  4 - 4  in  FIG. 1 ; 
           [0020]      FIG. 5 , which is similar to  FIG. 4 , is a view in cross-section of the machine taken on a line  5 - 5  in  FIG. 2 ; 
           [0021]      FIG. 6  is a perspective view from a front side of the machine in the  FIG. 2  mode; 
           [0022]      FIGS. 7 to 11  illustrate the use of an actuator key which is part of an interlock mechanism, in connection with foot-engaging structure, in changing the exercise machine from the stepper mode to the elliptical mode, and 
           [0023]      FIGS. 12 to 15  show the use of a similar actuator key, in connection with a handle of the exercise machine, in changing the exercise machine from the stepper mode to the elliptical mode. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
       [0024]      FIG. 1  of the accompanying drawings is a side view of an exercise machine  10  according to the invention in a first mode of operation.  FIG. 4  is a view in cross-section of the machine taken on a line  4 - 4  in  FIG. 1 , and  FIG. 3  illustrates in enlarged detail a portion of the machine in  FIG. 1 . 
         [0025]    Front and rear base members  12  and  14  respectively are located at extremities of a centrally positioned curved spine  16 —see  FIG. 6 . Curved supports  18  and  20  respectively extend upwardly from a small strut  22 , which is fixed to the spine close to the front base member  12 . A crosspiece  24  is fixed to upper ends of the curved supports. A curved support  30  is fixed between the crosspiece  24  and a pedestal  32  which extends upwardly from the spine  16  see  FIG. 5 . The members  12  and  14 , the spine, the supports  18  and  20 , and the support  30 , make up a stable support structure to which the various components of the machine are connected. 
         [0026]    An elongate, roughly oval, box-like structure  38  is fixed to the pedestal  32 . The structure  38  has two opposing sections  38 A and  38 B with a gap between them, which are fixed to the supports  18 ,  20  respectively (the section  36 B is largely hidden from view in  FIG. 6 ). A flywheel  44  is positioned in the gap and is mounted for rotation about an axle  46 . A friction brake pad  48  which is mounted to the support  30  can be moved by means of a screw device  50  to bear with variable force on an outer peripheral surface of the flywheel so that the force which is required to rotate the flywheel can be adjusted. 
         [0027]    A cog  52 , shown in dotted outline in  FIG. 1 , is mounted to the axle. 
         [0028]    Optionally frame components, not shown, are positioned between the supports  18  and  20  and a lower end of the support  30 . The frame components are then fixed to the pedestal  32 , in order to brace the pedestal. 
         [0029]    A pedal arrangement  60  is mounted for rotation about an axis  62  which traverses the pedestal. The pedal arrangement includes a first crank member  64  which terminates in a stub axle  66  and a second crank member  68 , on an opposed side of the pedestal, which terminates in a stub axle  70 . Each stub axle carries a respective roller  72  and  74 . The stub axle  66  and accompanying roller  72  are positioned below foot-engaging structure  80 . The roller  74  is below foot-engaging structure  82 . The arrangements are similar and thus the arrangement of the foot-engaging structure  80  only is described. 
         [0030]    Two elongate handles  84  and  86  respectively are fixed at respective pivot points  88  and  90  to the crosspiece  24 . At lower ends the handles are pivotally connected at respective points  92  and  94  to cross members  96  and  98 . The foot-engaging structures  80  and  82  are attached to respective upper surfaces of opposed ends of the cross members  96  and  98 . 
         [0031]    Each foot-engaging structure has a flat platform  100  with small upstanding peripheral flanges  102 , which help to retain a user&#39;s foot engaged with the platform. The roller  72  is positioned on a lower side of the cross member  96  and is held engaged with the lower surface by means of a guide rod  106  which extends in a longitudinal direction of the cross member so that the roller  72 , constrained by the crank member  64 , can move freely to and fro on the underside of the cross member  96 . 
         [0032]    A bracket  108  is fixed to a side of the cross member at a selected location and extends downwardly. The bracket is shaped so that it does not interfere with movement of the roller—see  FIG. 5 . The bracket has a central fixing formation  110  in the form of a hole or passage. 
         [0033]    On an opposing side the foot-engaging structure  82  has a platform  120  with peripheral formations  122 , a guide rod  126 , and a bracket  128  which has a hole  130 . 
         [0034]    A cog  140 , shown in dotted outline in  FIG. 1 , is mounted to an axle which extends through the axis  62  and to which the crank members  64  and  68  are fixed. A chain  142 , located inside the structure  38 , connects the cog  140  to the cog  52 . 
         [0035]    The front base member  12  has two apertures  150  and  152  at opposing ends which directly underlie lower ends of the handles  84  and  86  respectively. Locking pins  154  and  156  are respectively positioned inside these lower ends. The pins are movable, in a controlled and regulated way by means of an actuator key as is described hereinafter between elevated positions in which the handles can move freely past the front base member and lowered positions at which the pins are engaged with the base members. Leading ends  162  of the pins, see  FIG. 1 , are tapered to facilitate entry of the pins into the holes  150  and  152  respectively. 
         [0036]    With the exercise machine in the mode shown in  FIG. 1 , referred to herein as a stepping mode, the pins  154  and  156  are respectively engaged with the holes  150  and  152 . The handles are thus effectively locked to the supporting structure and are constrained against pivotal movement around the respective pivot points  88  and  90 . The pedal arrangement  60  on the other hand can be actuated by a user who is standing on the foot-engaging structures  80  and  82  and who grips upper ends of the handles  84  and  86 . When pedal action takes place the rollers  72  and  74  rotate about the axis  62 . The two platforms  100  and  120  do not rotate with the stub axles for they are fixed to the respective cross members  96  and  98  which can pivot about the respective points  92  and  94 . The platforms thus rise and fall in respective vertical planes as the rollers are rotated, by the crank members, about the axis  62 . This offers the user a stepping-type action with the user&#39;s feet moving substantially in vertical planes up and down. 
         [0037]    To convert the machine to the second, elliptical mode, shown in  FIG. 2 , the locking pins  154  and  156  are raised and are held in elevated positions in a manner which is described hereinafter. The stub axles are then aligned with the corresponding holes  110  and  130  in the respective brackets  108  and  128  and, by using interlock mechanisms  162  and  164 , only notionally shown in  FIG. 5 , the stub axles are locked to the corresponding cross members  96  and  98 . 
         [0038]    When a user exerts a pedalling action the platforms  100  and  120  are rotated about the axis  62 . The path which each platform follows is usually not truly circular and, for convenience at least, is referred to herein as an elliptical path. This type of movement is permitted because the handles, and hence the cross-members, are detached from the front base member. The handles move to and fro, reciprocating in each instance about the respective pivot points  88  and  90 . The user&#39;s feet rest on the respective platforms which are pivotally linked to the handles  84 ,  86  via the cross pieces  94  and  96 . The feet are thus subjected to a compound motion which is a combination of the rotational crank movement and a sliding/reciprocating motion which is coupled to the reciprocating movement of the handles. 
         [0039]    In each mode the user exerts energy on the exercise machine via the pedal arrangement. In the elliptical mode the user additionally is able to input energy via the handles  84  and  86 . 
         [0040]    Rotational movement of the pedal arrangement is translated into rotational movement of the flywheel via the cogs  140  and  52  and chain  142 . The flywheel thus exerts a resistance force which opposes movement of the pedal arrangement. The resistance force can be varied by means of the friction brake pad  48  to suit the requirements of an exerciser. 
         [0041]    In the aforegoing description the stepping mode ( FIG. 1 ) is produced by locking the handles to the front base member  12 . The elliptical mode is achieved by fixing the stub axles, at selected positions, to the platforms  100  and  120 , via the cross-members  96  and  98 . If the handles are locked to the front base member and if the stub axles are fixed to the cross-members then no movement of the machine&#39;s components is possible. On the other hand if the handles are disengaged from the front base member and, at the same time, the stub axles are disengaged from the platforms, then a potentially dangerous situation exists for movement of components of the exercise machine can take place in an unguided or unrestricted manner. To prevent this from occurring it is preferred to make use of an interlock mechanism which ensures that it is not possible for the handles to be freely pivotally movable about the pivot points  88  and  90  and, at the same time, for the rollers to be movable to and fro on the undersides of the respective platforms.  FIGS. 7 to 15  illustrate how this type of interlocking capability is achieved. 
         [0042]      FIGS. 7 to 11  illustrate in detail the operation of the interlock mechanism  162  in a zone of the exercise machine which lies in a circled area marked IM. The interlock mechanism  162  is based on the use of an actuator key  180  which is shown in perspective in  FIG. 7 . The key has a shaft  182 , a handle  184  fixed to one end of the shaft and a sleeve  186  fixed to an opposing end of the shaft. A pin  188  is fixed to and projects from the sleeve. A six-sided member  190  extends from an end of the sleeve which is remote from the handle  184 . 
         [0043]      FIG. 8  shows the actuator key engaged with an interlock component  192  which projects from the bracket  108 . In this arrangement the machine  10  is in a stepper mode.  FIGS. 10 and 11  show two successive stages in the use of the actuator key when the exercise machine is converted from the stepper mode to the elliptical mode. 
         [0044]    The interlock component  192  comprises a tube  194  which is formed with two hook-shaped slots  200  and  202  respectively (see  FIG. 9 ). The pin  162  is replaced by a short rod  204  which is slidably positioned inside the tube  194 . A spigot  206  extends from the rod. The rod is movable in a direction  208  ( FIG. 10 ) against the action of a spring, not shown, mounted internally in the tube  194  to a position at which the roller is locked to the bracket  108 . 
         [0045]    The slot  202  has a short limb  202 A, a long limb  202 B and a bridging section  202 C. With the spigot  206  in the short limb the rod  204  is kept projecting to a maximum extent from the tube and the bracket  108  is thereby coupled to the roller  72  (not shown). If the spigot  206  is moved to the long limb  202 B then, under the action of the internal spring referred to, the rod  204  is movable inside the tube  194  in a direction  210  which is opposite to the direction  208 . The rod is thereby retracted and the roller is thereby disengaged from the bracket. 
         [0046]    The slot  200  has a long limb  200 A, a short limb  200 B and a bridging section  200 C. When the actuator key is engaged with the tube  194  the pin  188  is guided for movement along the long limb  200 A and then, with rotatable movement of the actuator key, through the bridging section  200 C. The pin can then be retracted slightly, while remaining captive to the tube, with the pin  188  moving inside the short limb  200 B. 
         [0047]    An end of the rod  204  which is positioned inside the tube  194  has a six-sided socket  208  which is of complementary shape to, and which is engageable with, the member  190 . This allows rotational movement of the actuator key to be transferred to the rod  204 . 
         [0048]      FIG. 8  shows the actuator key with the pin  188  in the short limb  200 B. The spigot  206  is in the long limb  202 B. This means that the rod  204  is in a retracted position and the roller  72  can be moved to and fro below the platform  100 . 
         [0049]      FIG. 10  illustrates the actuator key pushed, in the direction  208 , inwardly towards the platform. The pin  188  is moved to an extreme position inside the short limb  200 B and the spigot  206  is moved by the same amount inside the long limb  202 B. As shown in  FIG. 11  the actuator key is then rotated in an anticlockwise direction. The pin  188  then moves in the bridging section  200 C and the spigot  206  moves in the bridging section  202 C. 
         [0050]    When the actuator key  180  is moved inwardly the rod  204  is moved to couple the roller  72  to the bracket. When the pin  188  reaches the long limb  200 A it is possible for the actuator key to be withdrawn from the tube  194 . The rod  204  is not free to move in the same direction i.e. to a retracted position, because its movement is prevented by the spigot  206  engaging with a limiting surface of the short limb  202 A. The rod  204  is thus held in a position at which the roller is fixed to the bracket i.e. the machine is now in an elliptical mode. 
         [0051]    It is apparent that the actuator key can only be disengaged from the tube  194  when the rod  204  is in an operative position i.e. with the machine in an elliptical mode. 
         [0052]    The aforegoing description relates to one side of the exercise machine only. Corresponding movements are carried out on the interlock mechanism  164 , on the opposing side of the machine, which is based on the use of a second actuator key  180 A which in all material respects is the same as the actuator key  180 . 
         [0053]      FIGS. 12 to 15  show the use of the actuator key  180 A on the opposing side, to release the handle  86  so that it is free to pivot about the pivot point  90  when elliptical-type movement takes place. 
         [0054]    A lower end of the handle  86 , which is tubular, is formed with an elongate slot  220 . At one end the slot terminates in a hook-shaped formation which defines a short slot  224  and a transverse slot  226 . A tubular locking pin  156  projects from a lower end of the handle. This construction is shown, in context, in  FIG. 6 . 
         [0055]    In  FIG. 12  the pin  156  is engaged with the hole  152  in the front base member  12 . The actuator key  180 A is then aligned with an enlarged lower end  228  of the slot  220  and is inserted into the slot ( FIG. 13 ). The actuator key passes through a corresponding aperture  230  which is formed through a wall of the pin  156 . This pin is biased downwardly by means of a spring, not shown, located inside the handle. 
         [0056]    The actuator key  180 A is then raised ( FIG. 14 ) and moves along the elongate slot  220 . The pin  156  is also raised and is thereby disengaged from the hole  152 . At an upper limiting position the actuator key is moved along the transverse slot  226  to the short slot  224  and allowed to descend slightly. The actuator key is then held at an elevated position and the locking pin is also kept elevated ( FIG. 15 ). It is not possible for the actuator key to be disengaged from the handle unless the locking pin is again engaged with the hole  152 . A similar process is carried out on the other handle when the exercise machine is converted to the elliptical mode. 
         [0057]    In summary and referring only to one side of the exercise machine, a single locking key is used to secure the handle to the front base member or to fix the roller to the bracket. The key can only be disengaged from the handle when the handle is engaged with the front base member. Similarly the key can only be disengaged from the bracket if the roller is engaged with the bracket. When conversion of the exercise machine from the stepper mode to the elliptical mode takes place the roller is first fixed to the bracket—this is while the handle is fixed to the front base member. With the roller fixed to the bracket the actuator key is removable and can then be used to release the handle from the front base member. The actuator key is then kept engaged with the handle. If conversion to the stepper mode is to take place the handle is first locked to the front base member and when this occurs the actuator key can be removed from the handle. Thereafter the actuator key is used to release the roller from the bracket but, when this occurs, the key is held captive as shown in  FIG. 8 . The key also has an unusual shape at its operative end i.e. the six-sided member and the projecting pin  188 . It is therefore not possible, at least under normal conditions of usage, for the handle to be released from the front base member and at the same time for the roller to be released from the bracket.