Patent Publication Number: US-6905443-B1

Title: Gradient adjusting structure of a treadmill

Description:
BACKGROUND OF THE INVENTION 
   The present invention is related to a gradient adjusting structure of treadmill, which is able to stably support the treadmill. 
   A conventional treadmill is generally equipped with a gradient adjusting structure for changing the slope of the tread platform and enhancing exercising effect.  FIG. 9  shows an adjustment device for adjusting the height of the frame of the conventional treadmill. The adjustment device includes two linking plates  7  each of which is formed with a frame pivot hole  71 , a front support lever pivot hole  72  and a long shaft pivot hole  73 . The frame pivot hole  71  and the front support lever pivot hole  72  are respectively positioned at front end and the middle of the linking plate  7  in higher positions. The long shaft pivot hole  73  is positioned at rear end of the linking plate  7  in a lower position. Via the frame pivot holes  71 , the linking plates  7  are respectively pivotally disposed on two sides of front end of the tread frame  6 . Via the front support lever pivot holes  72 , the linking plates  7  are pivotally connected with the front support lever  5 . Then, a long shaft rod  731  is passed through the long shaft pivot holes  73  of the linking plates  7 . Finally, an adjustment mechanism  8  is pivotally disposed on the long shaft rod  731 . The operating end of the adjustment mechanism  8  transversely extends out to the tread frame  6  and is located on the locating plate  51  of the front support lever  5 . Accordingly, by means of the operating member of the adjustment mechanism  8 , when the drag worm  81  is displaced forward or rearward, the long shaft rod  731  is synchronously moved. At this time, the linking plates  7  will swing about the front support lever pivot hole  72 , whereby the height of the position of the flame pivot hole  71  is adjusted to change the support angle of the tread frame  6  so as to ascend/descend the tread frame  6 . 
   The tread frame  6  is pivotally connected with the front support lever  5  via the two linking plates  7 . The drag worm  81  of the adjustment mechanism  8  is extended/retracted to ascend/descend the tread frame  6 . Accordingly, the weight loaded on the tread frame  6  and the tread force are borne by the linking plates  7 . The force exerted onto the linking plates  7  is applied to the drag worm  81  of the adjustment mechanism  8 . When the tread frame  6  is descended to a lowest position, the drag worm  81  is extended to a longest extent. Under such circumstance, a bending stress is applied to the drag worm  81  to wear the worm  81 . A sleeve  82  is fitted on the drag worm  81  between two locating plates  51  to buffer the force applied to the drag worm  81 . However, this is not so helpful to the drag worm  81  with respect to bending stress and even the sleeve  82  will interfere with the rotation of the drag worm  81 . 
   Furthermore, the tread frame  6  is ascended/descended with the front support lever pivot holes  72  of the linking plates  7  serving as the axis. In order to lift the front end of the tread frame  6  to a certain height, the distance between the front support lever pivot hole  72  and the frame pivot hole  71  must have a certain length. Accordingly, the force arm h 1  between the front support lever pivot hole  72  and the frame pivot hole  71  of the linking plate  7  will be excessively long. When the tread frame  6  is upward pivotally folded about the frame pivot hole  71 , as shown in  FIG. 10 , the overlong force arm h 1  will increase the force applied to the front support lever pivot hole  72  of the linking plate  7 . Therefore, after folded, the tread frame  6  has poor support strength and can be hardly stably supported. 
   SUMMARY OF THE INVENTION 
   It is therefore a primary object of the present invention to provide a gradient adjusting structure of a treadmill including a base seat and a tread platform mounted between two columns of the base seat. The bottom of front end of the tread platform has at least one stop block. The gradient adjusting device has two symmetrical adjusting members and a telescopic rod. Each adjusting member has a first and a second ends containing a certain angle and outward extending. The center of the adjusting member is pivotally connected with inner face of the column near bottom end thereof. The first ends of the adjusting members are respectively pivotally connected with two sides of front end of the tread platform. A transverse beam is fixed between the second ends of the adjusting members and positioned under the bottom of front end of the tread platform, whereby the stop block of the tread platform can abut against the transverse beam. One end of the telescopic rod is pivotally connected with one side of the transverse beam, while the other end of the telescopic rod is pivotally connected with the bottom of the tread platform. When the tread platform is lowered to the bottom, the stop blocks of the bottom of front end of the tread platform will abut against the transverse beam of the adjusting members so as to support the tread platform. Accordingly, the weight loaded on the tread platform and the tread force are shared by the transverse beam with the tread platform. Also, the bending stress exerted onto the telescopic rod is minimized to prevent the telescopic rod from being worn. 
   It is a further object of the present invention to provide the above gradient adjusting structure of the treadmill in which when the rear end of the tread platform is upward folded about the pivot sections between the adjusting members and the columns of the base seat, the first ends of the adjusting members pivotally connected with the tread platform are upward swung along with the tread platform. Accordingly, the force arm between the pivot sections of the adjusting members pivotally connecting with the columns and the tread platform is shortened. Therefore, the folded tread platform can be stably supported. 
   The present invention call be best understood through the following description and accompanying drawings wherein: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective assembled view of the present invention; 
       FIG. 2  is a perspective exploded view of the present invention; 
       FIG. 3  is a side view of the present invention, in which the tread platform is not ascended/descended; 
       FIG. 4  is a side view of the present invention, in which the tread platform is ascended; 
       FIG. 5  is a side view of the present invention, in which the tread platform is folded; 
       FIG. 6  is a side view of the present invention, in which the stop block of front end of the tread platform abuts against the transverse beam; 
       FIG. 7  is a side view of a second embodiment of the present invention, showing a manually operable gradient adjusting structure; 
       FIG. 8  is a side view of the second embodiment of the present invention, showing the operation of the manually operable gradient adjusting structure; 
       FIG. 9  shows a height adjustment device for tread frame of a conventional treadmill; and 
       FIG. 10  is a view according to  FIG. 9 , showing that the tread frame of the conventional treadmill is folded. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Please refer to  FIGS. 1  to  3 . The present invention is related to a gradient adjusting structure of a treadmill including a base seat  1 , a tread platform  2  and a gradient adjusting device  3 . 
   The left and right sides of the base seat  1  respectively have two sidebars  11 . An upward extending column  12  is disposed at front end of each side bar  11 . A handle  13  is disposed at top end of the column  12 . A controlling panel  14  is mounted between the two handles  13  for a user to hold when treading. The controlling panel  14  is for the user to control and adjust the treading speed and slope of the tread platform  2 . One end of each of two support levers  15  is pivotally connected with rear end of the side bar  11 . The other end of the support lever  15  is pivotally connected with one side of the middle section of the tread platform  2 . 
   The front end of the tread platform  2  is mounted between the two columns  12  of the base seat  1 . A tread belt  21  is disposed in the tread platform  2 . The tread belt  21  is driven by a motor  22  to circularly rotate. The bottom of front end of the tread platform  2  has at least one stop block  23 . In this embodiment, two stop blocks  23  are respectively disposed on two sides of the bottom of front end of the tread platform  2 . The stop block  23  has a stop face  231  facing rear end of the tread platform  2 . The bottom of middle section of the tread platform  2  has a pivot seat  24 . 
   The gradient adjusting device  3  has two symmetrical adjusting members  31  and a telescopic rod  32 . Each adjusting member  31  has a first and a second ends  311 ,  312  containing a certain angle and outward extending. The center of the adjusting member  31  is pivotally connected with inner face of the column  11  near bottom end thereof. The first ends  311  of the adjusting members  31  are respectively pivotally connected with two sides of front end of the tread platform  2 . A transverse beam  313  is fixed between the second ends  312  of the adjusting members  31  and positioned under the bottom of front end of the tread platform  2 . The transverse beam  313  has an abutting face  3131  corresponding to the stop face  231  of the stop block  23  of the tread platform  2 . The other face of the transverse beam  313  opposite to the abutting face  3131  has a pivot seat  3132  pivotally connected with one end of the telescopic rod  32 . The other end of the telescopic rod  32  is pivotally connected with the pivot seat  24  of the bottom of the tread platform  2 . The telescopic rod  32  is driven by a power source  321  to extend/retract. In this embodiment, the telescopic rod  32  is a worm and the power source  321  is a lifting motor. 
     FIGS. 3 and 4  show the gradient adjusting operation of the tread platform of the present invention. The power source  321  controls tile telescopic rod  32  to retract so as to pull the transverse beam  313  of the second ends  312  of the adjusting members  31  to move rearward. The front end of the tread platform  2  is upward lifted about the pivot sections between the adjusting members  31  and the columns  12  of the base seat  1 . Accordingly, the slope of the tread platform  2  on the base seat  1  can be adjusted. Reversely, when lowering the tread platform  2 , the power source  321  controls the telescopic rod  32  to extend forward so as to push the transverse beam  313  forward. At this time, the front end section  22  of the tread platform  2  is lowered. When the tread platform  2  is lowered to the bottom, the stop faces  231  of the stop blocks  23  of the bottom of front end of the tread platform  2  will abut against the abutting face  3131  of the transverse beam  313  of the adjusting members  31  so as to support the tread platform  2 . 
     FIG. 5  shows the folding operation of the tread platform of the present invention. When folding the treadmill, the rear end of the tread platform  2  is upward folded about the pivot sections between the adjusting members  31  and the columns  12  of the base seat  1  so as to minify the volume of the treadmill and facilitate storage thereof. When the rear end of the tread platform  2  is upward folded, the two support levers  15  of the base seat  1  will be extended along with the tread platform  2  to support the folded tread platform  2 . 
   When the tread platform  2  is lowered to the bottom, the stop faces  231  of the stop blocks  23  of the bottom of front end of the tread platform  2  will abut against the abutting face  3131  of the transverse beam  313  of the adjusting members  31  so as to support the tread platform  2  as shown in FIG.  6 . When the telescopic rod  32  is extended to a longest extent to make the tread platform  2  lowered to the bottom, the weight loaded on the tread platform  2  and the tread force are shared by the transverse beam  23  with the tread platform  2 . Accordingly, the bending stress exerted onto the telescopic rod  32  is minimized to prevent the telescopic rod  32  from being worn. 
   Furthermore, when the rear end of the tread platform  2  is upward folded about the pivot sections between the adjusting members  31  and the columns  12  of the base seat  1 , the first ends  311  of the adjusting members  31  pivotally connected with the tread platform  2  are upward swung along with the tread platform  2 . Accordingly, the force arm h 2  between the pivot sections of the adjusting members  31  pivotally connecting with the columns  12  and the tread platform  2  is shortened. Accordingly, the folded tread platform  2  can be stably supported. 
   In the above embodiment, the telescopic rod  32  is driven to extend/retract by means of electric measure so as to ascend/descend the front end of the tread platform  2 . Alternatively, the front end of the tread platform  2  can be manually ascended/descended. As shown in  FIGS. 7 and 8 , in a second embodiment of the present invention, a seat body  25  is disposed on top face of front end of the tread platform  2 . The telescopic rod  32  of the gradient adjusting device  3  is pivotally disposed on the seat body  25 . A threaded seat  33  is pivotally disposed on the pivot seat  3132  of the transverse beam  313  of the adjusting members  31 . The threaded seat  33  has an inner thread hole  331  in which one end of the telescopic rod  32  is screwed. The other end of the telescopic rod  32  is provided with a rotary wheel  34 . By means of rotating the rotary wheel  34 , the telescopic rod  32  drives the threaded seat  33  to ascend or descend. Accordingly, the two adjusting members  31  are driven to swing about the pivot sections between the adjusting members  31  and the columns  12 . Therefore, the tread platform  2  can be manually operated to ascend or descend. 
   The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.