Abstract:
A weight stack including a stack of weight plates received in a holder cage to move with the cage along guide rods. A selector pin is received through the cage in a passage in a selected weight plate to connect them for movement as a unit. The weight plates are contained in proper alignment within the cage by stationary members received within the cage at appropriate edge portions of the weight plates.

Description:
OBJECTS OF THE PRESENT INVENTION  
       [0001]     The present invention relates to weight stacks for exercise machines and has for one of its objects the provision of a novel and improved weight stack for use with machines for exercising and/or testing muscles of the human body.  
         [0002]     Another object of the present invention is to provide a weight stack that reduces friction resulting from the moving weights during an exercise as compared to conventional weight stacks that employ a center guide rod for aligning the plates.  
         [0003]     Another object of the present invention is to provide a weight stack that will achieve the above objects and yet may be manufactured with conveniently available parts and easily operated in practice with new, or standard or conventional exercise machines.  
       SUMMARY OF PREFERRED EMBODIMENT OF THE PRESENT INVENTION  
       [0004]     In summary, a preferred embodiment of the present invention includes a plurality of weights stacked on a stationary surface and enclosed within a surrounding cage. The cage is movable vertically within a stationary frame to raise and lower one or more of the weights. A connecting pin received through the cage and into a selected weight serves to connect the cage and one or more selected weights so that the selected weights will be raised and lowered when the cage is raised and lowered by any suitable means including a cable or strap or linkage connected to the cage and driven by an exerciser either directly or through a movement arm driven by the exerciser. 
     
    
     DRAWINGS  
       [0005]     Other objects of the present invention will become apparent from the following more detailed description taken in conjunction with the attached drawings in which:  
         [0006]      FIG. 1  is a perspective view of a leg press exercise machine incorporating a weight stack constituting a preferred embodiment of the present invention;  
         [0007]      FIG. 2  is a view similar to  FIG. 1  but with the weights in a raised position;  
         [0008]      FIG. 3  is a perspective view of a cage and support frame included in the weight stack but excluding the weights for clarity; and  
         [0009]      FIG. 4  is a view similar to  FIG. 3  but with certain parts omitted for clarity.  
     
    
     DETAILED DESCRIPTION  
       [0010]     Referring now to the drawings in detail there is shown for illustrative purposes only a leg press exercise machine including a weight stack generally designated  10  constituting a preferred embodiment of the present invention. In the specific embodiment shown, the weight stack serves as a resistance in connection with a leg press exercise machine however it will be understood that the weight stack may be used in conjunction with any other exercise machine or even alone where it is driven directly by an exerciser who lifts and lowers the weights through a cable or other connecting means.  
         [0011]     The leg press machine in the specific embodiment shown includes a carriage  12  slidable along rails  14  fixed on a base  16 . The exerciser is positioned on a seat (not shown) fixed to a seat base  18  on carriage  12  with the exerciser&#39;s feet engaging a stationary footrest  20  fixed to one side of the weight stack frame  22 . In the specific embodiment shown, footrest  20  is connected to the weight stack frame by two pairs of horizontal arms  24  while vertical legs  28  connected to the arms  24 , 26  are supported on a base  30  fixed to one side of the weight stack frame.  
         [0012]     When the exerciser seated on the carriage  12  exerts pressure with the legs on the footrest  20 , the carriage slides rearwardly on the rails  14  from the position shown in  FIG. 1  to the position shown in  FIG. 2 . A cable or strap  32  connected to the front  34  of the carriage also moves rearwardly with the carriage. Strap  32  is trained about a pulley  36  and extends upwardly to and about a pulley  37  on the top frame piece  11  and then downwardly to the top of the weight stack to raise one or more weights as will be further described. When the exerciser relieves pressure on the footrest, the weights will descend and draw the carriage back to the start position shown in  FIG. 1 .  
         [0013]     In accordance with the present invention, the weight stack includes a weight holder shown in the form of a cage generally designated  40  including a bottom frame  42  having a rectangular shape including opposite parallel sides  44  and ends  46  as best shown in  FIGS. 3 and 4 . The opposite ends  46  have rollers  48  engaged on vertical guide rods  50  extending between the upper and lower frame portions  11  and  13  of the weight stack frame to which they are fixed. In the specific embodiment shown the cage  40  includes opposite sides  52  shown as elongated vertical bars fixed at their lower ends to the bottom frame  42  and at their upper ends to a top piece or yoke  54 . The latter has rollers  56  journalled in its opposite ends engaged on rods  50 . It will then be see that the cage  40  which includes the bottom frame  42 , side bars  52  and yoke  54  is slidable vertically along guide rods  50  in response to horizontal movement of the carriage  12  which is transmitted to the cage via the strap  32  which connects to the yoke  54  at pin  58 .  
         [0014]     In the specific embodiment shown the weights are rectangular plates  60  stacked within the cage  40  on a horizontal surface preferably a platform  62  fixed on the lower frame piece  13 . Weight plates  60  are contained in alignment within the cage by four right-angle bars or angle irons  64  fixed to the weight stack frame through spacer members fixed to the vertical frame portions  15 , and foot members  68  fixed to the lower frame piece  13  as best shown in  FIG. 3 . Spacer members  66  are provided with recesses to receive the guide rods  50 .  
         [0015]     Weight plates  60  are connected to the cage  48  by a selector pin received through one of a plurality of apertures  72  spaced along the vertical bars  52  of the cage in alignment with passages in the sides of the weight plates  60 .  FIG. 2  shows the selector pin  70  in the third-from-the-top weight plate  60  and the uppermost three weight plates raised above the stack in response to the movement of the carriage  12  rearwardly. When the exerciser relieves pressure on the footrest, the raised weight plates  60  will descend to the stack as the carriage moves forwardly to the start position. To change the resistance, the selection pin  70  is simply repositioned in another weight plate through the use of the apertures  72  in the vertical bars  52  of the cage.  
         [0016]     It will thus be seen that the present invention eliminates the need of a conventional center stack pin received through apertures in the weight plates and the attendant friction produced from this system which of course is common place in the art. At the same time the present invention provides a sturdy and reliable weight stack that is easy to operate while also being susceptible to economical manufacture for use with standard or new exercise machines.  
         [0017]     Although one preferred embodiment of the present invention has been shown and described above, it will be appreciated that various other embodiments will be apparent to those of ordinary skill in the art but without departing from the scope of the present invention which is indicated in the appended claims.