Patent Publication Number: US-8113995-B1

Title: Elliptical exercise machine with adjustable stride

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent Ser. No. 12/985,390, filed on Jan. 6, 2011. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an exercise apparatus, and more particularly to an elliptical exercise machine with adjustable stride. 
     2. Description of the Related Art 
     Various stride adjustable elliptical exerciser machines have been proposed to meet the consumer&#39;s needs. For example, Taiwanese patent Number M286688 discloses an elliptical exerciser machine including a threaded rod and a threaded sleeve that engages the threaded rod. Relative rotation between the threaded rod and the threaded sleeve results in a change in a maximum distance between two pedals. Such a stride-adjusting arrangement, however, is complicated in structure, and is difficult to adjust. 
     SUMMARY OF THE INVENTION 
     The object of this invention is to provide a stride adjustable elliptical exercise machine that has a simple structure and that is easy to adjust. 
     Accordingly, an elliptical exercise machine of this invention includes two swing rods connected pivotally to a base, a flywheel, two supporting rods connected pivotally between the flywheel and the swing rods, two pedal rods slidable respectively on the supporting rods, and a motion transmitting device. The device includes a fixed member fixed on the base, a rotatable member locked releaseably on the fixed member at a selected angular position, two cranks connected pivotally to the rotatable member, and two links each having a first pivot portion connected pivotally to the corresponding pedal rod, a second pivot portion connected pivotally to the corresponding swing rod, and a third pivot portion connected pivotally to the corresponding crank. The links are driven by the cranks to move the pedal rods forwardly and rearwardly on the supporting rods, respectively. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of this invention will become apparent in the following detailed description of two preferred embodiments of this invention, with reference to the accompanying drawings, in which: 
         FIG. 1  is a front perspective view of the first preferred embodiment of a stride adjustable elliptical exercise machine according to this invention; 
         FIG. 2  is a rear perspective view of the first preferred embodiment; 
         FIG. 3  is a partly exploded perspective view of the first preferred embodiment; 
         FIG. 4  is a fragmentary schematic view of a link of the first preferred embodiment; 
         FIG. 5  is a schematic side view of a fixed member, a rotatable member, and a locking member of the first preferred embodiment, illustrating that the rotatable member is disposed at a first angular position; 
         FIGS. 6 and 7  are side views of the first preferred embodiment, illustrating respectively maximum and minimum distances between centers of a sliding wheel and a flywheel when the rotatable member is disposed at the first angular position; 
         FIG. 8  is a schematic side view of the fixed member, the rotatable member, and the locking member of the first preferred embodiment, illustrating that the rotatable member is disposed at a second angular position; 
         FIGS. 9 and 10  are side views of the first preferred embodiment, illustrating respectively maximum and minimum distances between centers of the sliding wheel and the flywheel when the rotatable member is disposed at the second angular position; 
         FIG. 11  is a perspective view of the second preferred embodiment of a stride adjustable elliptical exercise machine according to this invention; 
         FIG. 12  is a partly exploded perspective view of the second preferred embodiment; 
         FIG. 13  is a fragmentary schematic side view of the second preferred embodiment; 
         FIG. 14  is a view similar to  FIG. 13  but illustrating how a rotatable member is rotated counterclockwise relative to a fixed member; and 
         FIGS. 15 and 16  are side views of the first preferred embodiment, illustrating respectively maximum and minimum distances between centers of a sliding wheel and a flywheel when the rotatable member is disposed at an angular position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 and 2 , the first preferred embodiment of a stride adjustable elliptical exercise machine  100  according to this invention includes a base  1 , two swing rods  2 , a flywheel  3 , two supporting rods  4 , two pedal rods  5 , and a motion transmitting device  6 . 
     With further reference to  FIG. 3 , the base  1  is disposed on a supporting surface, such as the ground surface, and includes a main body  11 , and a post  12  disposed fixedly on a front end of the main body  11 . The swing rods  2  are connected pivotally to the base  11 , and are spaced apart from each other in a left-to-right direction. Each of the swing rods  2  includes a horizontal pivot rod portion  21  connected rotatably on the post  12 , an upright rod portion  22  extending perpendicularly from and disposed under the horizontal pivot rod portion  21 , and a grip portion  23  extending from and disposed above the horizontal pivot rod portion  21  and aligned with the upright rod portion  22 . As such, the grip portions  23  can be operated to pivot the upright rod portions  22  forwardly and rearwardly about the horizontal pivot rod portions  21 . 
     The flywheel  3  is disposed rotatably on a rear end portion of the base  11 . Each of the supporting rods  4  is straight, and has a front end  41  connected pivotally to a bottom end of the upright rod portion  22  of the corresponding swing rod  2 , and a rear end  42  is slightly higher than the front end  41  and connected pivotally to the flywheel  3 . The rear ends  42  of the two supporting rods  4  are connected respectively and pivotally to two opposite sides of the flywheel  3 . The pedal rods  5  are disposed respectively on top surfaces of the supporting rods  4  for permitting the feet of the user to step thereon such that, when the flywheel  3  is rotated, each of the feet is moved in an elliptical path of motion simulating natural walking or running foot movement. 
     The motion transmitting device  6  includes a fixed member  61  and a rotatable member  62 . The fixed member  61  is disposed fixedly on and in front of the post  12 , and includes two vertical sidewalls  611  spaced apart from each other in a left-to-right direction. The rotatable member  62  includes two vertical pivot walls  621  respectively adjacent to outer side surfaces of the sidewalls  611 . The pivot walls  621  are connected respectively and pivotally to the sidewalls  611  by a pivot pin unit including two pivot pins  622 . In this embodiment, each of the pivot pins  622  is a rivet. As such, the rotatable member  62  is rotatable relative to the fixed member  61  about the pivot pins  622 . The motion transmitting device  6  further includes two cranks  63  and two links  64 . The two cranks  63  have upper ends  631  connected respectively and pivotally to left and right sides of the rotatable member  61 , and lower ends  632 . In this embodiment, the upper end  631  of each of the cranks  63  is formed with a pivot hole  633 . The rotatable member  62  includes a pivot rod  623  extending through the pivot walls  621  and into the pivot holes  633  in the cranks  63 , respectively. As such, the cranks  63  are rotatable relative to the rotatable member  62  about the pivot rod  623 , and the position of the pivot rod  623  relative to the fixed member  61  can be changed by rotating the rotatable member  62  relative to the fixed member  61 . 
     Each of the links  64  has a first pivot portion  641  connected pivotally to the corresponding pedal rod  5 , a second pivot portion  642  disposed above the first pivot portion  641  and connected pivotally to the upright rod portion  22  of the corresponding swing rod  2 , and a third pivot portion  643  spaced apart from the second pivot portion  642  and connected pivotally to the lower end  632  of the corresponding crank  63 . Each of the pedal rods  5  has a pivot rod portion  51  connected pivotally to the first pivot portion  641  of the corresponding link  64  at a front end thereof, and a pedal portion  52  disposed behind and connected to the pivot rod portion  51  and having a bottom end provided with a sliding wheel  53  slidable forwardly and rearwardly on the top surface of the corresponding supporting rod  4 , such that the corresponding pedal rod  5  is rotatable about a central axis of the sliding wheel  53 . As such, when the rotatable member  62  is rotated relative to the fixed member  61 , the links  64  are driven respectively by the cranks  63  to pivot forwardly or rearwardly to change travel of the pedal portions  52  of the pedal rods  5 , thereby adjusting the user&#39;s stride. 
     With further reference to  FIG. 4 , in this embodiment, each of the links  64  includes an inverted L-shaped first rod member  644  and a second rod member  645 . Each of the first rod members  644  includes a lower rod body  646  having the first pivot portion  641  at a bottom end thereof, and an upper rod body constituting the second pivot portion  542  and extending perpendicularly from a top end portion of the lower rod body  646 . The upright rod portion  22  of each of the swing rods  2  is formed with a horizontal pivot hole  221  permitting the second pivot portion  642  of the corresponding link  64  to extend therethrough, so that the corresponding link  64  can rotate relative to the corresponding upright rod portion  22 . The second rod member  645  of each of the links  64  has the third pivot portion  643  at an upper end thereof, and a non-circular horizontal engaging hole  647  at a bottom end thereof. An engaging block  648  is disposed fixedly on an end of each of the second pivot portions  642 , has a non-circular cross-section, and is received fittingly within the engaging hole  647  in the corresponding second rod member  645 , so that the corresponding second pivot portion  642  is connected fixedly to the bottom end of the corresponding second rod member  645 . As such, when the second rod members  645  are activated respectively by the cranks  53 , the first rod members  644  co-rotate respectively with the second rod members  645 . In this embodiment, the first and second rod members  644 ,  645  of each of the links  64  form an angle θ therebetween. The angle θ is an obtuse angle. 
     With further reference to  FIG. 5 , the fixed member  61  further includes a curved wall  612  interconnecting the sidewalls  611 , and the rotatable member  62  further includes a curved wall  624  interconnecting the pivot walls  621 . A positioning unit is disposed for maintaining the rotatable member  62  at a desired position relative to the fixed member  61 . The positioning unit includes a plurality of curvedly arranged positioning holes  613 , a through hole  625 , and a locking member  65 . The positioning holes  613  are formed through the curved wall  612 , are vertically spaced apart from each other, and are spaced apart from a common axis of the pivot pins  622  by the same distance (i.e., the positioning holes  613  are arranged in a circumferential direction with respect to the common axis of the pivot pins  622 ). The through hole  625  is formed in the curved wall  624  of the rotatable member  62 . The locking member  65  extends through the through hole  625  in the rotatable member  62  to engage a selected one of the positioning holes  613  in the fixed member  61 , thereby locking the rotatable member  62  releaseably on the fixed member  61  at a selected one of a plurality of angular positions. 
     In this embodiment, the through hole  625  in the rotatable member  62  is a threaded hole. The locking member  65  has a rotary knob portion  651  exposed outwardly of the rotatable member  62  for manual operation, a threaded rod portion  652  engaging the through hole  625  in the rotatable member  62  and having an end connected to the rotary knob portion  651 , and an engaging rod portion  653  connected to an opposite end of the threaded rod portion  652  and engaging the selected positioning hole  613  in the fixed member  61  to lock the rotatable member  62  on the fixed member  61 . The rotary knob portion  651  can be operated to remove the engaging rod portion  653  from the selected positioning hole  613  to thereby release the rotatable member  62  from the fixed member  61 . 
     One of the swing rods  2 , one of the supporting rods  4 , one of the pedal rods  5 , one of the cranks  63 , and one of the links  64  at the same side (i.e., the left side) will be described in the succeeding paragraphs. 
     With particular reference to  FIGS. 5 ,  6 , and  7 , when the locking member  65  is inserted into the third (counted from the top) positioning hole  613  so that the rotatable member  62  is disposed at a first angular position, as shown in  FIG. 5 , each of the pedal rods  5  is movable between a front limit position whereat the centers of the sliding wheel  53  the flywheel  3  are spaced apart from each other by a maximum distance (D 1 ) (see  FIG. 6 ), and a rear limit position shown in  FIG. 7  whereat the centers of the sliding wheel  53  and the flywheel  3  are spaced apart from each other by a minimum distance (D 2 ) (see  FIG. 7 ). When the rotatable member  62  is disposed at the first angular position, D 1  is 578 mm, and D 2  is 163 mm. As a consequence, the travel of the pedal portion  52  is D 1 −D 2 =578 mm−163 mm=415 mm (approximately 16 inches). 
     With particular reference to  FIGS. 8 ,  9 , and  10 , when it is desired to slightly increase the travel of the pedal rod  5 , the locking member  65  is first operated to separate from the third positioning hole  613 . Next, the rotatable member  62  is rotated relative to the fixed member  61  in a counterclockwise direction (I) (see  FIG. 8 ) to align the locking member  65  with the fourth (counted from the top) positioning hole  613 . Afterwards, the rotary knob portion  651  is operated to engage the engaging rod portion  653  with the fourth positioning hole  613  to thereby lock the rotatable member  62  on the fixed member  61  at a second angular position. During counterclockwise rotation of the rotatable member  62 , the third pivot portion  643  is pivoted downwardly about the second pivot portion  642  to thereby rotate the first rod member  644  in a direction (II), thus moving the pedal rod  5  forwardly on the supporting rod  4 . Hence, an angle formed between the link  64  and the upright rod portion  22  of the swing rod  2  and, thus, the travel of the pedal rod  5  are increased. In this embodiment, when the rotatable member  62  is disposed at the second angular position, the travel of the pedal rod  5  is about 17 inches. To reduce the travel of the pedal rod  5 , the locking member  65  can be operated to engage the first or second (counted from the top) positioning hole  613 . 
     In this embodiment, when the locking member  65  engages the first positioning hole  613 , the travel of the pedal portion  52  is about 14 inches; when the locking member  65  engages the second positioning hole  613 , the travel of the pedal portion  52  is about 15 inches; when the locking member  65  engages the fifth positioning hole  613 , the travel of the pedal portion  52  is about 18 inches; when the locking member  65  engages the sixth positioning hole  613 , the travel of the pedal portion  52  is about 19 inches; and when the locking member  65  engages the seven positioning hole  613 , the travel of the pedal portion  52  is about 20 inches. 
     Alternatively, the number and positions of the positioning holes  613  may be changed. In addition, the positioning holes  613  may be replaced with a plurality of positioning grooves. If this occurs, the rotatable member  62  may be provided with a spring-biased engaging member or ball that is engageable within a selected one of the positioning grooves. 
       FIGS. 11 ,  12 , and  13  show the second preferred embodiment of a stride adjustable elliptical exercise machine  200  according to this invention, which is similar in construction and operation to the first preferred embodiment except for the motion transmitting device  6 ′. 
     The motion transmitting device  6 ′ further includes a driving mechanism  7  for driving rotation of the rotatable member  62 ′ relative to the fixed member  61 ′, and a control module  8  disposed on a top end of the post  12  of the base  1  and electrically connected to the driving mechanism  7  such that travel of the pedal portions  52  of the pedal rods  5  can be adjusted through operation of the control module  8 . 
     The driving mechanism  7  is located above the fixed member  61 ′, and includes a housing  70  disposed fixedly between two supporting plate portions  121  of a U-shaped bracket that is secured on the post  12 . The driving mechanism  7  further includes a horizontal pivot shaft  71  disposed on the rotatable member  62 ′, and a movable member  72  having a bottom end sleeved rotatably on the pivot shaft  71 . The pivot shaft  71  includes a bolt  711  and a nut  712  engaging the bolt  711 . The bolt  711  extends through holes  626  in the pivot walls  621  and a hole  722  in a bottom end sleeve portion  721  of the movable member  72 . The nut  712  engages an end of the bolt  711 , and abuts against one of the pivot walls  621  for locking the bolt  711  on the rotatable member  62 ′. As such, the movable member  72  is rotatable about the pivot shaft  71 . 
     The driving mechanism  7  further includes a stud  73  and a driving motor  74 . The stud  73  has a threaded rod portion  731  extending rotatably through the housing  70  so that the stud  73  is rotatable relative to the base  1 , and a gear portion  732  disposed on a top end of the threaded rod portion  731  and in the housing  70 . A rod body  723  of the movable member  72  is formed with a threaded hole  724  that is open outwardly and that engages the threaded rod portion  731  of the stud  73 . As such, the stud  73  engages threadably a top end of the movable member  72 . The driving motor  74  is disposed within the housing  70 , and includes a driving gear  741  meshing with the gear portion  732  of the stud  73 . A transmission line  75  is disposed for connecting the driving motor  74  electrically to the control module  8 . The control module  8  is operable to activate the driving motor  74  so as to drive rotation of the stud  73  in a positive or reverse direction, thereby resulting in downward or upward movement of the rod body  723  of the movable member  72 . When the rod body  723  of the movable member  72  is moved downwardly, the movable member  72  pushes downwardly and rotates the rotatable member  62 ′ relative to the fixed member  61 ′ about the pivot pins  622  in a counterclockwise direction to increase the travel of the pedal portions  52  of the pedal rods  5 . When the rod body  723  of the movable member  72  is moved upwardly, the movable member  72  pulls upwardly and rotates the rotatable member  62 ′ relative to the fixed member  61 ′ about the pivot pins  622  in a clockwise direction to reduce the travel of the pedal portions  52  of the pedal rods  5 . 
     The movable member  72  further includes a curved plate body  725  extending from a bottom end of the rod body  723 . The sleeve portion  721  is disposed at a bottom end of the curved plate body  725 . Since the curved plate body  725  is resilient, rotational angle of the rotatable member  62 ′ can be increased, and the distance traveled by the rod body  723  of the movable member  72  can be reduced. 
     Referring to  FIGS. 14 ,  15 , and  16 , when it is desired to increase travel of the pedal portions  52  of the pedal rods  5 , through operation of the control module unit  8 , a control signal is emitted from the control module unit  8  to the driving mechanism  7  via the transmission line  75 , such that the driving motor  74  is activated to drive positive rotation of the stud  73 . During positive rotation of the stud  73 , the rod body  723  of the movable member  72  is moved downwardly in a direction (III) (see  FIG. 14 ), so that the curved plate body  725  cooperates with the sleeve portion  721  and the pivot shaft  71  to rotate the rotatable member  62 ′ relative to the fixed member  61 ′ about the pivot pins  622  in a counterclockwise direction (I) (see  FIG. 14 ), thereby resulting in rotation of the link  64  about a central axis of the second pivot portion  642  of the link  64  in a clockwise direction (II) (see  FIG. 15 ) and forward movement of the pedal rod  5 . Consequently, travel of the pedal portions  52  of the pedal rods  5  is increased. 
     When it is desired to reduce travel of the pedal portions  52  of the pedal rods  5 , through operation of the control module unit  8 , a control signal is emitted from the control module unit  8  to the driving mechanism  7  via the transmission line  75 , such that the driving motor  74  is activated to drive reverse rotation of the stud  73 . During reverse rotation of the stud  73 , the rod body  723  of the movable member  72  is moved upwardly, so that the curved plate body  725  cooperates with the sleeve portion  721  and the pivot shaft  71  to rotate the rotatable member  62 ′ relative to the fixed member  61 ′ about the pivot pins  622  in a clockwise direction (I), thereby resulting in rotation of the link  64  about the central axis of the second pivot portion  642  of the link  64  in a counterclockwise direction and rearward movement of the pedal rod  5 . Consequently, travel of the pedal portions  52  of the pedal rods  5  is reduced. 
     In view of the above, the elliptical exercise machine  100 ,  200  of this invention has a simple structure, and is easy and convenient to adjust the stride. Thus, the object of this invention is achieved. 
     With this invention thus explained, it is apparent that numerous modifications and variations can be made without departing from the scope and spirit of this invention. It is therefore intended that this invention be limited only as indicated by the appended claims.