Abstract:
A folding treadmill offering buffering effect during folding and unfolding comprises a base that has a circular tread belt as well as a power cylinder. The power cylinder includes a pressurization chamber and an oil-air cylinder chamber, wherein the oil-air cylinder chamber is loaded with pressured air and oil of a predetermined amount. Due to velocity difference between air and oil, a phased-changeable deceleration resistance can be provided during folding and unfolding the treadmill. Further, the characteristics of the power cylinder is related to buffer and balance so as to achieve the buffering effect in both lifting and lowering of the base. Thereupon, a safe altitude of the base can be defined and a designed structure contributing to users&#39; safety can be accomplished.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to folding treadmills for indoor exercise and, more particularly, to one offering buffering effect during folding and unfolding thereof. 
         [0003]    2. Description of Related Art 
         [0004]    Treadmills are commonly used in limited spaces to provide exercise and fun by simulating outside terrain with a tread belt moving in circles. A conventional treadmill may be bulky and heavy, resulting in unnecessarily taking up more indoor space when not in use. 
         [0005]    Though some efforts have been made to develop folding treadmills, which can be folded into smaller size for convenient storage, treadmills are still bulky and heavy. Therefore, during frequent folding and unfolding operations, treadmills are apt to bring danger to users. Especially during an unfolding operation, the potential danger may even serious due to the weight of the treadmill. Once there is any carelessness, such potential danger significantly related to safety concerns may substantially harm a user. Hence, a need exits for an improved folding treadmill without the foregoing disadvantage. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention has been accomplished under these circumstances in view. 
         [0007]    In view of that conventional folding treadmills lack for buffer structures and functions, the inventor of the present invention, urged by the motive of ameliorating the prior arts, has conducted repeated research and experiments to develop a folding treadmill offering buffering effect during folding and unfolding thereof. The disclosed subject matter primarily comprises a base that has a circular tread belt as well as a power cylinder therein such that the disclosed treadmill can have the base lifted upward or drawn downward by the cylinder so as to offer a buffering effect related to the lifting and lowering motions of the base. 
         [0008]    On the other hand, in the present invention, it is also taken into consideration that if a simple “air cylinder” which implements variation of air pressure to control the stretch and retraction thereof is used as power cylinder of the present invention, since air molecules are unstable and uncontrollable, a user may be jammed accidentally when the pressure release of the air cylinder can not be stopped properly, or when the air cylinder stretches and retracts out of control to make the base fall or raise suddenly. Thus, the present invention implements the power cylinder having an oil-air cylinder chamber so as to alternately utilize oil pressure and air pressure. Thereupon, during a folding or unfolding operation of the disclosed treadmill, a phased-changeable deceleration resistance can be provided due to the velocity difference between air and oil so that safety on using the disclosed subject matter is enhanced. 
         [0009]    Moreover, the present invention provides a simplified operating method that allows a user to easily fold or unfold the disclosed treadmill by lightly pulling the base to unbalance the pressure in the oil-air cylinder chamber. Thereby, the user can enjoy the pleasure of jogging while safe folding and unfolding operations are ensured with the advantage of simplified operating method and reduced manufacturing costs. 
         [0010]    To achieve above object, the present invention provides a folding treadmill offering buffering effect during folding and unfolding operation, comprising a base that has a circular tread belt as well as a power cylinder therein. The power cylinder includes a pressurization chamber and an oil-air cylinder chamber loaded with pressured air and oil of a predetermined amount, whereby a phased-changeable deceleration resistance can be provided during folding and unfolding the treadmill due to velocity difference between air and oil and the buffering effect effective in both lifting and lowering of the base can be achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
           [0012]      FIG. 1  is a partial schematic cross sectional view of the power cylinder according to the present invention; 
           [0013]      FIG. 2  is a schematic cross sectional view of the power cylinder according to the present invention showing a stretching motion thereof; 
           [0014]      FIG. 3  is another schematic cross sectional view of the power cylinder according to the present invention showing a retracting motion thereof; 
           [0015]      FIG. 4  is a perspective view of the folding treadmill according to the present invention; 
           [0016]      FIG. 5  is a schematic drawing showing the folding motion of the folding treadmill according to the present invention; 
           [0017]      FIG. 6  provides one embodiment of the folding treadmill according to the present invention folding; and 
           [0018]      FIG. 7  illustrates another embodiment of the folding treadmill according to the present invention folding. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]    Please refer to  FIG. 1  for a partial schematic cross sectional view of a power cylinder in the disclosed subject matter of the present invention. As shown, the power cylinder  5  has internally loaded with oil pressure and air pressure. The power cylinder  5  mainly comprises a piston assembly  57  installed on a wall  531  of a cylinder body  53  thereof. The piston assembly  57  is screwed to one end of a piston shaft  52 . The body of the piston shaft  52  pierces through central shaft holes respectively belonging to a terminal bush  54 , an oil seal  55 , and an inner fixed bush  56  inside the cylinder body  53  and extends out of the cylinder body  53 . An upper end of the piston shaft  52  is connected to an upper end piece  51  for being further assembled to a proper joint position of the treadmill. 
         [0020]    Additionally, an oil-air cylinder chamber  59  is provided between the piston assembly  57  and a lower end piece  60  in the power cylinder  5  while a pressurization chamber  58  is arranged between the piston assembly  57  and the inner fixed bush  56  of the cylinder body  53 . Thereby the air and oil in the pressurization chamber  58  can be reciprocally moved between the pressurization chamber  58  and the oil-air cylinder chamber  59  by the movement of the piston shaft  52  so as to achieve the internal balance of the power cylinder  5 . 
         [0021]    The oil-air cylinder chamber  59  of the present invention accommodates pressured air and oil of a predestined amount partially filled therein so as to keep providing the piston assembly  57  with an outward pushing force. The cylinder body  53  functions as a track where the piston shaft  52  linearly moves along. When the piston shaft  52  is pushed to move drive the piston assembly  57 , a resistance generated by the pressured air and oil stored in the oil-air cylinder chamber  59  against the piston assembly  57  buffs the moving force of the piston shaft  52 . At this time, due to the resistance, the base  3  lowers with a “buffed lowering effect” so that the base  3  can be controlled from falling down suddenly and the potential danger of hurting a user can be prevented. 
         [0022]    When the moving force of the piston shaft  52  is reduced or eliminated, the piston shaft  52  can be pushed back to the initial position thereof under the restoration of the pressured air and oil in the cylinder body  53  as well as the pressure variation generated thereby. Therefore, the base  3  can be controlled by a “buffed lifting effect” and prevented from rising up sharp so that a user can be protected from being rammed and hurt. 
         [0023]    The power cylinder  5  of the present invention has the piston shaft  52  piercing through the central shaft holes respectively belonging to the terminal bush  54 , the oil seal  55 , and the inner fixed bush  56  settled at one end of the cylinder body  53 . A piston  571 , a spacer  573 , and a special spacer  574  are sequentially put around an end portion  521  of the piston shaft  52 . A nut  575  is embedded into a terminal surface of the end portion  521  so that the piston  571  can be permanently fixed to the end portion  521  of the piston shaft  52  in a screwed way. An annular groove  576  is formed on the surface of the piston  571  and an O-shaped ring  572  is assembled to the annular groove  576  such that the O-shaped ring  572  snugly contacts the wall  531  of the cylinder body  53  in an airtight manner. 
         [0024]    When the treadmill is to be folded for storage, since the pressurization chamber  58  is presently full of pressured air as well as oil and bears the weight of the base  3 , once the base  3  is slightly pulled up to depart from cushion pads  43  on a bottom brace  4  of the treadmill, internal balance of the power cylinder  5  is broken. As a result, the pressured air and oil in the pressurization chamber  58  are continuously drained into the oil-air cylinder chamber  59  through the annular groove  576  on the piston  571 , as indicated by the dotted arrow sign in the drawing. Since the size of the annular groove  576  on the piston  571  is properly designed for the purpose of controlling the velocity where the pressured air and oil are drained, and since the draining process is preset as that the pressured air is drained into the oil-air cylinder chamber  59  prior to the oil, the power cylinder  5  is filled with a buffering force gradually. While the pressure ratio and counterforce in the oil-air cylinder chamber  59  are getting increased, the piston shaft  52  of the power cylinder  5  can slowly stretch to an ultimate position. Simultaneously, the piston shaft  52  gets lubricated so as to keep moving smoothly. Consequently, the base  3  of the treadmill is lifted slowly until it arrives the position alongside two upright supports  2  of the treadmill. The stretch motion of the power cylinder  5  can be seen clearly in  FIG. 2 . 
         [0025]    When the treadmill is to be unfolded for use, once the base  3  is slightly pulled downward to depart from the position alongside the upright supports  2 , the piston shaft  52  of the power cylinder  5  can be retracted into the oil-air cylinder chamber  59  under the weight of the base  3 . When the internal space of the oil-air cylinder chamber  59  is compressed by the piston shaft  52 , the pressured air and oil therein is inversely forced toward the pressurization chamber  58  through the annular groove  576  on the piston  571  in a continuous and slow manner, as indicated by the dotted arrow sign in the drawing. The base  3  of the treadmill keeps lowering continuously and slowly until pressure balance between the oil-air cylinder chamber  59  and pressurization chamber  58  is achieved. At the time that the pressure balance between the oil-air cylinder chamber  59  and pressurization chamber  58  is achieved, the base  3  of the treadmill arrives a safe altitude. Then, since the pressure in the oil-air cylinder chamber  59  can not rival the pressure caused by the weight of the base  3 , most of the oil and modicum of the pressured air remained in the oil-air cylinder chamber  59  are continuously drained into the pressurization chamber  58  through the annular groove  576  on the piston  571 . At this time, since the oil takes the most part of the remains in the oil-air cylinder chamber  59  and the velocity where the oil flows to the pressurization chamber  58  through the annular groove  576  on the piston  571  is relatively slower than that of the air, the present velocity of draining the remains is substantially lower than that before the base  3  arrives the safe altitude. Thereupon, a second phase of the movement of the base  3  of the treadmill is realized and the base  3  keeps lowering slowly until all pressure in the oil-air cylinder chamber  59  is drained out. By design under accurate calculation, the base  3  of the treadmill can at this time right touch the cushion pads  43 . As the pressure now in the pressurization chamber  58  cannot rival the pressure caused by the weight of the base  3 , the base  3  keeps lowering until its stably on the cushion pads  43 . By the resistance generated from the pressured air and oil against the piston assembly  57 , the moving force of the piston shaft  52  can be buffered and consequently the “buffed lowering effect” is achieved so that the base  3  can be controlled from falling down suddenly and the potential danger of hurting the user can be prevented. The above retracting motion of the power cylinder  5  is illustrated in  FIG. 3 . 
         [0026]    During the base  3  of the treadmill lowering toward the bottom brace  4 , if a user lightly pushes the lowering base  3  upward, the pressure ration between the oil-air cylinder chamber  59  and the pressurization chamber  58  inside the power cylinder  5  can be impacted and the pressure start to move inversely so that the base  3  of the treadmill can automatically return back to the position alongside the upright supports  2  of the treadmill slowly and the treadmill can get folded again. 
         [0027]    Please refer to  FIG. 4  for the perspective view of the folding treadmill according to the present invention. As clearly shown in the drawing, the disclosed subject matter is formed by some bent steel planks. The upright supports  2  are installed at both sides of the treadmill, respectively, and connected with a horizontal frame  11  of the base  3 . A wheel  44  is arranged at each side of the horizontal frame  11  for convenient moving of the treadmill. And a handrail  22  is arranged on each said upright support  2 . A connecting rod  21  is arranged perpendicular to the tops of the upright supports  2  for connecting the two upright supports  2 . Further, a circular tread belt  31  is assembled to the base  3 . A handle  32 , a positioning block  33  and a wheel  34  are provided at each end of a horizontal rod under the tread belt  31 , for being used during folding or unfolding the folding treadmill of the present invention. In the case that the treadmill is an electric one and requires a driving device  10  for driving the tread belt  31  so as to provide a user with particular exercise intensity, the driving device  10  may be deposited at one side of the base  3 . Otherwise, the driving device  10  can be omitted. Moreover, the base  3  is connected with the bottom brace  4  by means of a supporting frame  41  and a pivot shaft  42 . One said power cylinder  5  is provided at a proper position on each side of the bottom brace  4 . The upper end pieces  51  and lower end pieces  60  are fastened to proper positions on the treadmill so as to provide the resistance to the lifting or lowering motions of the base  3  in order to buffer the moving speed thereof. Additionally, the cushion pads  43  are provided near the positions where the bottom brace  4  joints the horizontal frame  11  for bearing the base  3  of the treadmill. Thereupon, the pivot shaft  42  pivots to facilitate smooth movement of the base  3 . 
         [0028]      FIG. 5  illustrates the folding motion of the folding treadmill according to the present invention. When the treadmill is to be folded for storage, since the pressurization chamber  58  is presently full of pressured air as well as oil and bears the weight of the base  3 , once the base  3  is slightly pulled up to depart from the cushion pads  43  on a bottom brace  4 , the pressured air and oil in the pressurization chamber  58  are continuously drained into the oil-air cylinder chamber  59  through the annular groove  576  on the piston  571 . Since the size of the annular groove  576  on the piston  571  is properly designed for the purpose of controlling the velocity where the pressured air and oil are drained, and since the draining process is preset as that the pressured air is drained into the oil-air cylinder chamber  59  prior to the oil, the power cylinder  5  is filled with the buffering force gradually. While the pressure ratio and counterforce in the oil-air cylinder chamber  59  are getting increased, the piston shaft  52  of the power cylinder  5  can slowly stretch to the ultimate position. Simultaneously, the piston shaft  52  gets lubricated so as to keep moving smoothly. Consequently, the base  3  of the treadmill is lifted slowly until it arrives the position alongside upright supports  2  of the treadmill. The stretch of the power cylinder  5  can be seen clearly in  FIG. 2 . 
         [0029]    When the treadmill is to be unfolded for use, once the base  3  is slightly pulled downward to depart from the position alongside the upright supports  2 , the piston shaft  52  of the power cylinder  5  can be retracted into the oil-air cylinder chamber  59  under the weight of the base  3 . When the internal space of the oil-air cylinder chamber  59  is compressed by the piston shaft  52 , the pressured air and oil therein is inversely forced toward the pressurization chamber  58  through the annular groove  576  on the piston  571  in a continuous and slow manner. The base  3  of the treadmill keeps lowering continuously and slowly until the pressure balance between the oil-air cylinder chamber  59  and pressurization chamber  58  is achieved. At the time that the pressure balance between the oil-air cylinder chamber  59  and pressurization chamber  58  is achieved, the base  3  of the treadmill arrives the safe altitude. Then, since the pressure in the oil-air cylinder chamber  59  can not rival the pressure caused by the weight of the base  3 , most of the oil and modicum of the pressured air remained therein are continuously drained into the pressurization chamber  58  through the annular groove  576  on the piston  571 . At this time, since the oil takes the most part of the remains in the oil-air cylinder chamber  59  and the velocity where the oil flows to the pressurization chamber  58  through the annular groove  576  on the piston  571  is relatively slower than that of the air, the present velocity of draining the remains is substantially lower than that before the base  3  arrives the safe altitude. Thereupon, the second phase of the movement of the base  3  of the treadmill is realized and the base  3  keeps lowering slowly until all pressure in the oil-air cylinder chamber  59  is drained out. By design under accurate calculation, the base  3  of the treadmill can at this time right touch the cushion pads  43 . As the pressure now in the pressurization chamber  58  cannot rival the pressure caused by the weight of the base  3 , the base  3  keeps lowering until it sits stably on the cushion pads  43 . After the base  3  of the treadmill is successfully positioned on the cushion pads  43  of the bottom brace  4 , a user can utilize the wheels  44  at the horizontal frame  11  and the wheels  34  at the ends of the base  3  to easily move and reposition the treadmill, for example, placing the treadmill by a window, in a balcony or at any other convenient or desired locations. Then the user can pull the handle  32  downward to make the position blocks  33  protrude and snugly contact the ground so that the disclosed subject matter can be firmly positioned on the ground. Afterward, the driving device  10  on the treadmill can be started and the user can take jogging with the treadmill. 
         [0030]    During the base  3  of the treadmill lowering toward the bottom brace  4 , if a user lightly pushes the lowering base  3  upward, the pressure ration between the oil-air cylinder chamber  59  and the pressurization chamber  58  inside the power cylinder  5  can be impacted and the pressure start to move inversely so that the base  3  of the treadmill can automatically return back to the position alongside the upright supports  2  of the treadmill slowly and the treadmill can get folded again. 
         [0031]    According to  FIG. 6 , in one concept of the present invention, for implementing the minimum amount of components, the present invention may use a single power cylinder  5  to perform the folding or unfolding motions as described previously and the user&#39;s safety can be also protected. 
         [0032]    As shown in  FIG. 7 , the power cylinders  5  can be also installed to the treadmill in a reverse direction with respect to the direction shown in  FIG. 4  and same efficiency can be achieved. Further, the power cylinders  5  may be of various types or implemented in other diverse ways so as to provide more flexible practicability. 
         [0033]    Although a particular embodiment of the invention has been described in detail for purposes of illustration, it will be understood by one of ordinary skill in the art that numerous variations will be possible to the disclosed embodiments without going outside the scope of the invention as disclosed in the claims.