Abstract:
A folding treadmill positioning structure includes a base frame, a treadmill platform, a first linkage connected between the base frame and the treadmill platform at the front side and defining a retaining portion, and a positioning device set, which includes a constraint member movably arranged on the rear side of the treadmill platform, a retaining member pivotally mounted on the front side of the treadmill and a connection member connecting the constraint member and the retaining member. When the treadmill platform is moved to the received position, the retaining member is forced into engagement with the retaining portion, locking the treadmill platform in the received position.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a folding treadmill and more particularly, to the positioning structural design of a folding treadmill. 
         [0003]    2. Description of the Related Art 
         [0004]    A prior art folding treadmill positioning structure is known comprising a base frame, a treadmill platform connected with the base frame and a positioning device set. The positioning device set comprises a lever, a stop member and a linking member connecting the lever and the stop member. The lever and the stop member are respectively disposed at the rear side and front side of the treadmill platform. The stop member is stopped against a stop portion of the base frame. The lever is operable to move the stop member away from the stop portion of the base frame, allowing the treadmill platform to be biased relative to the base frame and then received or set in horizontal. 
         [0005]    According to the aforesaid prior art design, when the treadmill platform is received, the stop member that is disposed at the front side of the treadmill platform is stopped against the base frame, holding the treadmill platform in the received position. At this time, the weight of the treadmill platform is simply supported on the stop member. After a long use of the treadmill, the stop member may be unable to support the treadmill platform firmly in the received position and may be disengaged from the stop portion of the base frame accidentally, causing the treadmill platform in to fall from the received position. This drawback bothers the user in using the treadmill. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a folding treadmill positioning structure, which enhances positive positioning, avoiding falling of the treadmill platform from the received position. 
         [0007]    It is another object of the present invention to provide a folding treadmill positioning structure, which facilitates receiving and positioning the treadmill platform. 
         [0008]    To achieve these and other objects of the present invention, a folding treadmill positioning structure comprises a base frame, a treadmill platform, a first linkage, and a positioning device set. 
         [0009]    The first linkage is connected between the base frame and the front side of the treadmill platform. The first linkage comprising a retaining portion. The positioning device set comprises a constraint member movably arranged on the rear side of the treadmill platform, a retaining member pivotally mounted on the front side of the treadmill platform and a connection member connecting the constraint member and the retaining member. 
         [0010]    Subject to the aforesaid technical features, the treadmill platform can be biased relative to the base frame between an operating position and a vertical received position. When the treadmill platform is moved to the received position, the retaining member is forced into engagement with the retaining portion, locking the treadmill platform in the received position. Further, the user can bias the constraint member to move the retaining member away from the retaining portion, allowing the treadmill platform to be moved to the operating position. Thus, the invention facilitates receiving and positioning the treadmill platform. 
         [0011]    Other and further benefits, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is an elevational view of a folding treadmill positioning structure in accordance with the present invention. 
           [0013]      FIG. 2  is an elevational view of a part of the present invention, illustrating the relationship between the constraint member of the positioning structure and the treadmill platform. 
           [0014]      FIG. 3  is an exploded view of the component parts of  FIG. 2 . 
           [0015]      FIG. 4  is a perspective view of a part of the present invention, illustrating the relationship between the retaining member of the positioning structure and the treadmill platform. 
           [0016]      FIG. 5  is an exploded view of the component parts of  FIG. 4 . 
           [0017]      FIG. 6  is an oblique right side view of the present invention, illustrating the treadmill in the operative position. 
           [0018]      FIG. 7  is an oblique right side view of the present invention, illustrating the treadmill in the received position. 
           [0019]      FIG. 8  is a sectional side view of a part of the present invention, illustrating the treadmill in the received position before biasing of the constraint member of the positioning structure. 
           [0020]      FIG. 9  is a sectional side view of a part of the present invention, illustrating the treadmill in the received position before biasing of the constraint member of the positioning structure and the retaining member engaged with the retaining portion of the left first link. 
           [0021]      FIG. 10  is a sectional side view of a part of the present invention, illustrating the treadmill in the received position and the constraint member of the positioning structure biased. 
           [0022]      FIG. 11  is a sectional side view of a part of the present invention, illustrating the treadmill in the received position before biasing of the constraint member of the positioning structure and the retaining member disengaged from the retaining portion of the left first link. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Referring to  FIGS. 1˜5 , a folding treadmill positioning structure  10  in accordance with the invention is shown comprising a base frame  20 , a treadmill platform  30 , a first linkage  40 , a second linkage  50  and a positioning device set  60 . 
         [0024]    The base frame  20  comprising a left frame bar  21  and a right frame bar  22  arranged in parallel, and a rear frame bar  23  connected between the left frame bar  21  and the right frame bar  22 . The left frame bar  21  defines therein a left sliding groove  211 . The right frame bar  22  defines therein a right sliding groove  221  that faces the left sliding groove  211 . 
         [0025]    The treadmill platform  30  is a rectangular frame member comprising opposing left side bar  31  and right side bar  32 , opposing front side bar  33  and rear side bar  34 , and a left connection member  311  and a right connection member  321  respectively perpendicularly extended from the left side bar  31  and the right side bar  32  adjacent to the front side bar  33 . According to this embodiment, the left connection member  311  and the right connection member  321  are thin plate members. As shown in  FIGS. 2 and 3 , the rear side bar  34  comprises a first locating member  35  that is formed of a substantially U-shaped thin plate member and comprises a locating hole  351  on each of the two distal ends thereof, and a downwardly protruding positioning portion  352  and a rectangular opening  353  at one side of the downwardly protruding positioning portion  352 . The treadmill platform  30  further comprises a plurality of connection ribs, for example, a first connection rib  36 , a second connection rib  37  and a third connection rib  38  transversely connected between the left side bar  31  and the right side bar  32  in a parallel manner and spaced from one another. The first connection rib  36  is connected between the distal end of the left connection member  311  and the distal end of the right connection member  321 . As shown in  FIG. 4  and  FIG. 5 , the first connection rib  36  comprises a second locating member  39  that is an integral rectangular open frame located on the first connection rib  36 . The second locating member  39  comprises two opposing lugs  391  respectively backwardly extended from the left and right sides thereof, a second locating hole  392  formed in each of the two lugs  391 , a through hole  393  located on the forwardly protruding top wall thereof and an elongated slot  394  located on the forwardly protruding top wall and forwardly extending from the through hole  393 . 
         [0026]    The first linkage  40  comprises a left first link  41  and a right first link  42  respectively and pivotally connected between the rear frame bar  23  and the left connection member  311  and right connection member  321 , and a left retractable rod member  43  and a right retractable rod member  44  respectively pivotally connected between the left first link  41  and right first link  42  and the second connection rib  37 . As shown in  FIG. 10 , the left first link  41  has a part of the body thereof forming a retaining portion  412  that is provided with a retaining ring  413 . 
         [0027]    The second linkage  50  comprises a left second link  51  and a right second link  52  respectively and pivotally connected with one end thereof to the left connection member  311  and the right connection member  321 , and a transverse rod member  53  connected between the other end of the left second link  51  and the other end of the right second link  52  and slidably coupled to the left sliding groove  211  and the right sliding groove  221 . 
         [0028]    Thus, as shown in  FIG. 6  and  FIG. 7 , by means of the first linkage  40  and the second linkage  50 , the treadmill platform  30  can be biased relative to the base frame  20  between a horizontal operating position P 1  and a vertical received position P 2 . When the treadmill platform  30  is moved to the horizontal operating position P 1 , the treadmill platform  30  is kept in a substantially parallel manner relative to the base frame  20 . At this time, the left retractable rod member  43  and the right retractable rod member  44  (not shown) are retracted to the shortest length, and the transverse rod member  53  is moved to the front end of the left sliding groove  211  and the front end of the right sliding groove  221  (not shown). When the treadmill platform  30  is moved to the vertical operating position P 2 , the treadmill platform  30  is kept in a substantially vertical manner relative to the base frame  20 . At this time, the left retractable rod member  43  and the right retractable rod member  44  (not shown) are extended to the longest length, and the transverse rod member  53  is moved to the rear end of the left sliding groove  211  and the rear end of the right sliding groove  221  (not shown). 
         [0029]    The positioning device set  60  comprises a constraint member  61 , a retaining member  62 , and a connection member  63  connecting the constraint member  61  and the retaining member  62 . 
         [0030]    According to this embodiment, the constraint member  61  is a thin plate member having an axle hole  611  located on one side thereof and a downwardly projecting positioning portion  612 . A first pivot pin  613  is inserted through the locating holes  351  of the first locating member  35  and the axle hole  611  to pivotally connect the constraint member  61  to the first locating member  35 . Further, a first elastic member  614  is set between the constraint member  61  and the first locating member  35 . According to this embodiment, the first elastic member  614  is a coil spring having two distal ends thereof respectively connected to the positioning portion  612  of the first elastic member  614  and the positioning portion  352  of the first locating member  35  and adapted for returning the constraint member  61  after the constraint member  61  having been biased. 
         [0031]    The retaining member  62  comprises a hook  621  located on one end thereof, an angled connection portion  622  located on the other end thereof, and an elongated slot  623  located on the angled connection portion  622 . The elongated slot  623  extends to the distal end edge of the angled connection portion  622 , forming an opening. The retaining member  62  further comprises a barrel  624  located on the middle between the hook  621  and the angled connection portion  622 , an extension portion  625  disposed adjacent to the barrel  624 , a second pivot pin  626  that is inserted through the second locating hole  392  of each of the two lugs  391  and the barrel  624  to pivotally connect the retaining member  62  to the second locating member  39 , and a second elastic member  627  sleeved onto the barrel  624 . As shown in  FIG. 4 , the second elastic member  627  according to the present preferred embodiment is a torsional spring having two opposite ends thereof respectively stopped against the extension portion  625  and the first connection rib  36  for enabling the retaining member  62  to be returnably biasable relative to the second locating member  39 . 
         [0032]    The connection member  63  according to the present preferred embodiment is a steel cable, having its one end inserted through the rectangular opening  353  of the first locating member  35  and connected to the constraint member  61  and its other end inserted in proper order through the through hole  393  of the second locating member  39  and the elongated slot  623  of the retaining member  62  and then secured to the angle of the angled connection portion  622  by a retainer  631 . 
         [0033]    Subject to the aforesaid technical features, as shown in  FIGS. 8˜11 , the hook  621  of the retaining member  62  is hooked up with the retaining ring  413  at the retaining portion  412  of the left first link  41  when the treadmill platform  30  is in the vertical received position P 2 , and therefore the treadmill platform  30  is locked in the vertical received position P 2  and prohibited from biasing relative to the base frame  20 . When the user biases the constraint member  61  upwards, the connection member  63  will be forced to move the retaining member  62 , thereby disengaging the hook  621  from the retaining ring  413  for allowing movement of the treadmill platform  30  relative to the base frame  20 . 
         [0034]    Therefore, subject to the interlocking structural design of the retaining member and the retaining portion, the invention achieves a better positioning effect, preventing the treadmill platform from falling from the vertical received position accidentally. Further, the user simply needs to apply a pressure to the constraint member when moving the treadmill platform from the operating position to the received position, and the treadmill platform will be locked in the received position positively when the user releases the hands from the treadmill platform and the constraint member after the treadmill platform reaches the received position. 
         [0035]    Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.