Patent Publication Number: US-7211029-B2

Title: Foldaway threadmill

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is related to a kind of foldaway treadmill, particularly to a kind of foldaway treadmill which contains designed pneumatic-hydraulic cylinder possessing pneumatic-hydraulic chamber and compressing chamber, separated by piston whereon there is a draining-functioned groove, filled with air and oil of suitable proportion to provide more safe, smooth and convenient folding up and out of foldaway treadmill than conventional ones. 
   2. Description of Related Art 
   Due to improper design, the conventional foldaway treadmills have the following problems: poor performance, and lacking perfect safety design to provide safe, smooth and convenient folding up and out. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a foldaway treadmill of lower cost and less complexity, with higher safety and better convenience, including: one pair of vertical posts with two holders, projecting from base frame and interconnected by one cross bar; one base frame containing one pair of wheels and shock-proof pad; one tread base containing rotatory tread belt, powered driver, fixing switch handles, fixing tips, and one pair of wheels; and one supporting unit containing four connecting plates, three or more cross bars, one rotating axle, and one or a plurality of pneumatic-hydraulic cylinders; characterized in that, inside the said pneumatic-hydraulic cylinders, there are pneumatic-hydraulic chamber and compressing chamber, separated by piston whereon there is a draining-functioned groove, filled with air and oil of suitable proportion to provide more safe, smooth and convenient folding up and out of foldaway treadmill than conventional ones. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates sectional view of pneumatic-hydraulic cylinder. 
       FIG. 2  illustrates sectional view of pneumatic-hydraulic cylinder in extending state. 
       FIG. 3  illustrates sectional view of pneumatic-hydraulic cylinder in retracting state. 
       FIG. 4  illustrates perspective view of foldaway treadmill of the present invention. 
       FIG. 5  illustrates motion perspective view of foldaway treadmill of the present invention. 
       FIG. 6  illustrates perspective view of another embodiment of foldaway treadmill of the present invention. 
       FIG. 7  illustrates perspective view of the further embodiment of foldaway treadmill of the present invention. 
   

   LIST OF REFERENCE NUMERALS 
   
       
         5  vertical post
         51  cross bar     52  holder     
         6  treadmill base
         60  cross bars     61  rotatory tread belt     62  fixing switch handle     63  fixing tip     64  wheel of tread base     
         7  supporting unit
         71  rotating axle     72  pivoting axle     73  pivoting axle     74  first connecting plate     76  cross bar     77  second connecting plate     
         8  pneumatic-hydraulic cylinder unit
         81  upper end of pneumatic-hydraulic cylinder     82  piston rod
             821  lower end of piston rod         83  cylinder
             831  cylinder inner wall         84  upper cylinder cover     85  oil seal     86  fixing sleeve     87  piston unit
             871  piston     872  o-ring     873  washer     874  special washer     875  screw nut     876  draining-functioned groove         88  compressing chamber     89  pneumatic-hydraulic chamber     90  lower cylinder cover     91  lower end of pneumatic-hydraulic cylinder     
         10  driving roller 
         11  base frame 
         12  cross bar of base frame 
         13  shock-proof pad 
         14  wheel of base frame 
     
  
   DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENTS 
   The present invention provides a foldaway treadmill of lower cost and less complexity, with higher safety and better convenience, by means of utilizing designed pneumatic-hydraulic cylinder which contains pneumatic-hydraulic chamber and compressing chamber, separated by piston whereon there is a draining-functioned groove, filled with air and oil of suitable proportion, to supply smooth and modified buffering force when folding up or out foldaway treadmill of the present invention by just lifting or pulling down treadmill slightly, and consequently more safe, smooth and convenient folding up and out of foldaway treadmill than conventional ones. 
   As illustrated in  FIG. 4 , foldaway treadmill of the present invention is made of steel tubes, which contains vertical posts  5 , base frame  11 , tread base  6 , supporting unit  7 , pneumatic-hydraulic cylinder unit  8 , driving roller  10 . 
   The each said vertical post  5  projects upwards from each front end of base frame  11 , with a cross bar  51  interconnecting right and left vertical post  5 , and with each vertical post  5  having a holder  52 . 
   The said tread base  6  includes: a plurality of cross bars  60  interconnecting both longitudinal sides of tread base  6 , one rotatory tread belt  61 , two fixing switch handles  62  located at each rear end of tread base  6 , two fixing tips  63  which extruding out to contact ground and keep the whole setup firmly positioned when pulling down fixing switch handles  62 , and two wheels  64  located at each rear end of tread base  6 . 
   The said supporting unit  7  includes: one cross bar  76 ; one rotating axle  71 ; a plurality of pivoting axles  72 ,  73 ; two first connecting plates  74 , each front end of which is pivoted to the corresponding front end of tread base  6  with the said rotating axle  71  spanning through both pivoting holes, and each rear end of which is pivoted to corresponding end of cross bar  12  which interconnects both rear ends of base frame  11 ; two second connecting plates  77 , each upper end of which is pivoted to the corresponding front end of tread base  6  with the said rotating axle  71  spanning through both pivoting holes, and each lower end of which is pivoted to corresponding front end of base frame  11  with the said pivoting axle  72  spanning through both pivoting holes; two said pneumatic-hydraulic cylinder unit  8 , each upper end  81  of which is pivoted to the suitable position of each said tread base  6 &#39;s longitudinal side, and each lower end  91  of which is pivoted to corresponding end of said pivoting axle  73  spanning between two first connecting plates  74 ; the said cross bar  76  interconnecting two front end of said first connecting plates  74 . 
   As illustrated in  FIG. 1 , the said pneumatic-hydraulic cylinder  8  includes: a cylinder body  83 ; piston rod  82 ; piston unit  87  engaged to piston end  821 , through which piston  871 , washer  873 , special washer  874  are mounted, and to which a nut  875  threadedly engaged; an annular groove  876  on piston&#39;s column face, to which an o-ring  872  is engaged with inner wall  831  of cylinder body  83  air-tightly contacted. 
   The piston rod  82  extends through the central holes of upper cylinder cover  84 , oil seal  85 , fixing sleeve  86 , with the rod end connecting upper end element which connects to a suitable position of the said treadmill alternatively. 
   The said pneumatic-hydraulic cylinder  8  has a pneumatic-hydraulic chamber  89  located within a space between the said piston unit  87  and lower end cover, and a compressing chamber  88  located within a space between the said piston unit  87  and fixing sleeve  86 , with drainage between each other to achieve balance of compressed air and oil of preset quantity during moving of piston rod  82 . 
   When folding up the foldaway treadmill of present invention (at this moment, the said compressing chamber  88  full of compressed air and oil of preset quantity under load of tread base  6 &#39;s weight), just lifting up the said tread base  6  slightly from shock-proof pad  13  will make compressed air and oil of preset quantity inside compressing chamber  88  drain through groove  876  on piston  871  into pneumatic-hydraulic chamber  89 , as indicated by arrows in  FIG. 2 . 
   As the gap of said groove  876  is designed to regulate speed of draining, the said tread base  6  will rise slowly and smoothly until touching said cross bar  51  of the said vertical post  5 . 
   When one wants to use foldaway treadmill of the present invention and folds it out, just pulling away said tread base  6  slightly from said cross bar  51  of the said vertical post will make piston rod  82  squeeze space of pneumatic-hydraulic chamber  89 , and compressed air and oil of preset quantity drains through groove  876  into compressing chamber  88 , as indicated by arrows in  FIG. 3 . 
   As illustrated in  FIG. 5 , before reaching pressure balance, the said tread base  6  continues to descend slowly and smoothly. Once all the air in pneumatic-hydraulic chamber  89  exhausted, the said tread base  6  reaches the safe positioning point, and at this moment, what remains inside the said pneumatic-hydraulic chamber  89  is all oil, and the oil will continue to drain into the said compressing chamber  88  through the said groove  876  under the load of the said tread base  6 &#39;s weight. 
   As the draining speed of oil through groove  876  is less than air, after the said safe positioning point, the said tread base  6  will descend even more slowly than before the said safe positioning point, and there is a second stage of even more slow folding after the said safe positioning point until all the oil inside the said pneumatic-hydraulic chamber  89  is exhausted completely and the said tread base  6  contacts the said shock-proof pad  13 . By deliberately calculating, on the said tread base  6 &#39;s contacting the said shock-proof pad  13 , all the oil inside the said pneumatic-hydraulic chamber  89  is just exactly exhausted completely, and the said tread base  6  stays firmly on the said shock-proof pad  13 . 
   If the oil inside the said pneumatic-hydraulic chamber  89  is exhausted before the said tread base  6  contacting the said shock-proof pad  13 , there is a gap between the said tread base  6  and the said shock-proof pad  13 , and it will make structure of supporting unit damaged easily. 
   There are wheels  14  in the rear ends of base frame, and wheels  64  in the rear ends of tread base, once the foldaway treadmill of the present invention folded out, the said treadmill can be moved to suitable place, and then can be positioned firmly with fixing tips extruding out by pressing down fixing switch handles  62 . 
   As illustrated in  FIG. 6 , the foldaway treadmill of present invention may also utilizes only one pneumatic-hydraulic cylinder to achieve smooth folding up and out. 
   As illustrated in  FIG. 7 , the foldaway treadmill of present invention may also utilizes pneumatic-hydraulic cylinders fixed in reverse direction to achieve the same object of folding up and out smoothly. 
   While the present invention has been described with reference to the preferred embodiments thereof, it is to be understood that modifications and variations may be easily made without departing from the spirit of this invention which is defined by the appended claims.