[0001]     This Application is a Continuation-In-Part of application Ser. No. 10/657,645, filed Sep. 8, 2003 (now abandoned), of the same title and inventorship. 
     
    
     BACKGROUND OF THE INVENTION AND PRIOR ART  
       [0002]     This invention relates in general to glider type exercise equipment, such as the equipment described and claimed in the inventor&#39;s U.S. Pat. Nos. 5,795,268, 5,857,940, D390,628 and D403,033, and in particular to a novel suspension system for such equipment. The patented exercise gliders feature very low impact in a device that simulates a full range of natural striding motion, including aggressive striding, for achieving both upper and lower body workouts.  
         [0003]     With the patented exercise devices, a full range of striding motion is very closely simulated while impact on the user&#39;s body is practically eliminated. Significantly, the aerobic effect experienced is readily controllable by merely accelerating the striding action and lengthening the stride, precisely as can be done when aggressively striding over a stationary surface. However, unlike striding, with the inventive device a user can lean backward and forward to transfer significant weight to his arms, chest and back without loss of balance or control. This not only increases the aerobic effort and enables an upper body workout, but also varies the muscle groups that are being exercised.  
         [0004]     The spring suspension system of the present invention incorporates a shock absorbing arrangement that adds a slight cushion effect to the rear of each foot platform for enhancing the gliding action. Essentially, springs permit the heel ends of the foot platforms to move up and down (within defined limits) to resiliently modify the radial paths traversed by the foot platforms. The effect is to further reduce the stress on both the user&#39;s body and the exercise machine structure. The novel suspension system is achieved with a simple, low cost, shock absorbing arrangement that may be readily added to the patented gliders.  
       OBJECTS OF THE INVENTION  
       [0005]     A principal object of the invention is to provide a novel suspension system for a low impact glider exercise apparatus.  
         [0006]     Another object of the invention is to provide a novel glider exercise apparatus.  
         [0007]     A further object of the invention is to provide an improved suspension system for a low impact glider exercise apparatus. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     These and other objects and advantages of the invention will become apparent upon reading the following description in conjunction with the drawings, in which:  
         [0009]      FIG. 1  is a perspective of a fold-away low impact glider apparatus incorporating the novel suspension system of the invention;  
         [0010]      FIG. 2  shows one version of a spring cage of the invention;  
         [0011]      FIG. 3  is a side elevation of the spring cage of  FIG. 2 ;  
         [0012]      FIG. 4  is a plan view of the spring retainer of the spring cage of  FIG. 2 ;  
         [0013]      FIG. 5  is a cross section of the spring retainer of  FIG. 4 , taken along the line  5 - 5 ;  
         [0014]      FIGS. 6 and 7  are views of the base  45  of the  FIG. 2  spring cage;  
         [0015]      FIG. 8  is a enlarged partial cross section taken along line  8 - 8  of  FIG. 1  illustrating the attachment of the spring cage to the rear leg of the glider apparatus;  
         [0016]      FIG. 9  is an enlarged partial cross section taken along line  8 - 8  of  FIG. 1  illustrating a second, preferred version of a spring cage of the invention and its attachment to the glider apparatus;  
         [0017]      FIGS. 10 and 11  are two views of the preferred spring cage of  FIG. 9 ;  
         [0018]      FIGS. 12 and 13  illustrate the normal and extended positions of the preferred form of suspension system of the invention;  
         [0019]      FIGS. 14-18  are views of the pinch guard  86  of the spring cage of  FIG. 9 ;  
         [0020]      FIGS. 19 and 20  illustrate the rubber bushings of the spring cage of  FIG. 9 ; and  
         [0021]      FIGS. 21 and 22  illustrate the bushing separators. 
     
    
     SUMMARY OF THE INVENTION  
       [0022]     The invention comprises a shock absorbing spring cage in the link that supports the swingable foot platform from the frame of a glider type exercise machine.  
       DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]     Referring to  FIG. 1 , a glider type exercise apparatus  10  as shown in the above-mentioned patents includes a fold-away frame consisting of front legs  12 , 13  and rear legs  14 , 15  that are arranged for swingably supporting a pair of foot platforms  20 , 21 . A pair of swing arms,  16 , 17 , pivotally supported on a cross member  18  of the frame, is pivotally connected to the toe ends of foot platforms  20 , 21 , respectively. The heel ends of foot platforms  20 , 21  are coupled by heel end pivots  34 , 35  to a pair of links  24 , 26 , respectively. The links  24 , 26  are in turn coupled, via spring cages  36 , 38  to a pair of rear pivots  30 , 31  on legs  12 , 13 , respectively. While the links  24 , 26  may be rigid, in the preferred embodiments of the apparatus, the links comprise steel cables. The apparatus functions, in a well-known manner to enable a user standing on the foot platforms and grasping the swing arms to engage in an aerobic upper and lower body workout with minimal impact to his body.  
         [0024]      FIGS. 2-7  illustrate various features of one version of spring cage  36  of the invention, it being understood that spring cage  38  is a mirror image thereof. A top plate  40 , preferably made of steel, is welded to the upper ends of a pair of steel tie rods  43 , 44  that are welded at their lower ends to a steel base plate  45  ( FIGS. 6 and 7 ) to form a generally cylindrical structure. Top plate  40  includes a hole  41  for pivotal mounting to rear pivot  30  and a small hole  42  for attaching the upper end of a tension spring  50 . The lower end of tension spring  50  is connected to an intermediate member  52 , preferably made of steel, that serves as a coupler for the upper end of link  24 . In practice, link  24  is a cable having a threaded stud secured to its upper end for secure engagement with intermediate member (cable coupler)  52 . A compression spring  54 , which encircles link  24 , has its lower end seated in a spring retainer  55  ( FIGS. 4 and 5 ). A polyurethane washer  53  is positioned atop compression spring  54  and serves to cushion the impact between intermediate member  52  and compression spring  54  upon elongation of tension spring  50 . A plastic shield  56  covers the major portions of spring cage  36 .  
         [0025]     As more clearly shown in  FIGS. 4 and 5 , spring retainer  55  includes a pair of edge notches  59 , 60  that partially encircle the round circumferences of tie rods  43 , 44 . The spring retainer has a central orifice  57  through which link  24  freely passes and a circular recess  58  for receiving the bottom end of compression spring  54 . Spring retainer  55  is preferably made of a plastic material and is dimensioned such that it is a force fit between tie rods  43 , 44 .  
         [0026]      FIGS. 6 and 7  show details of base plate  45 , in particular the end notches  47 , 48  which are welded to the ends of tie rods  43 , 44 , respectively and the central orifice  46 , through which link  24  freely passes.  
         [0027]     In  FIG. 8 , details of the pivotal attachment of the spring cage to the upper (rear) part of front leg  12  are shown. Pivot  30  comprises a cylindrical pin  62  which passes through leg  12  and includes an axle portion  64 . A screw  63  engages pin  62  with washer  66 . A contoured spacer  67 , through which pin  62  passes, engages the circular periphery of leg  12  and presents a flat surface that engages a plastic washer  68 . A bearing  61 , having a stepped diameter for engaging hole  41  in top plate  40  and an inner, hole-engaging axle portion  64 , centers the spring cage  36  on pin  62 . A plastic cover  70  has a stepped orifice  71  for accepting a washer  66 , with everything being secured together by the screw head  65 . The arrangement enables free pivotal movement of spring cage  36  about pin  62 , thus defining the rear pivot  30 .  
         [0028]      FIGS. 9-13  illustrate another, preferred, form of shock absorbing arrangement of the present invention. Spring cage  36  in this embodiment comprises a frame having an upper plate  80 , a lower plate  85  and a pair of steel tie rods  81  and  82  welded together in a manner similar to that previously described in connection with  FIGS. 2 and 3 . The shock absorbing arrangement in this preferred embodiment differs in that compression rubber bushings  84  ( FIGS. 19,20 ) and plastic spacers  83  ( FIGS. 21 and 22 ) are provided, rather than a combination of tension and compression springs. The end of link  24 , which is preferably a cable, is secured to a cylindrical rod  24   a  that includes a threaded end  24   b  to which a nut  24   c  is attached. Bushings  84  and spacers  83  are stacked around rod  24   a  and supported between lower plate  85  and a pinch guard  86  ( FIGS. 14-18 ). Normally, the stack of bushings  84  is undistorted as shown in  FIG. 12 , but when load is applied to link  24 , bushings  84  compress, as illustrated by the bulging in  FIG. 13 . The bushings  84  may be of any suitable material such as rubber or polyurethane, whereas the spacers  83  and pinch guard  86  are preferably molded of plastic. A decorative cover, consisting of an inner portion  90  and an outer portion  91 , is also molded of plastic.  
         [0029]     A gap  89 , of variable length, exists between the bottom of upper plate  80  and threaded end  24   b  of rod  24   a . Pinch guard  86  not only secures the top of the stack of bushings, but substantially blocks access to gap  89  at all times, thus precluding inadvertent admission of objects into this gap. Referring to  FIGS. 14-18 , pinch guard  86  includes a pair of broad wings  86   a  and  86   b  that extend upward from a base  86   c . Base  86   c  is molded with a depending collar  86   d , having an inner diameter sized to fit over rod  24   b , an outer diameter sized to fit within bushing  84  and forming a hexagonally-shaped aperture  86   e  for captivating nut  24   c . Its ends are formed with semicircular cutouts  86   f  and  86   g  for sliding engagement with the spring cage tie rods  81  and  82 , respectively ( FIG. 10 ).  
         [0030]     Each rubber bushing  84 , as illustrated in  FIGS. 19 and 20 , is of cylindrical shape and includes a circular opening  84   a  for receiving either pinch guard  86  or the spacers  83 . As shown in  FIGS. 21 and 22 , each spacer  83  includes a circular base  83   a , slightly larger than the outer diameter of bushing  84 , and upper and lower collars  83   b  and  83   c  that are dimensioned to fit in circular opening  84  of bushing  84  and around rod  24   a  It will be appreciated by those skilled in the art that the spring cage may be located anywhere in the link, although its placement as shown at rear pivot  30  is preferred. In the first-described embodiment of the invention tension spring  50  has an overall length of 3.375 in. and a spring rate of 76 lbs/in. and compression spring  54  has an overall length of 1.5 in. and a spring rate of 108 lbs/in. In the second-described, preferred embodiment of the invention, the bushings are cylindrical, each having a 1.00 inch outer diameter, a 0.375 inch inner diameter and a 1.00 inch length. The rubber material has a hardness of 70 Shore A.  
         [0031]     What has been described is a novel suspension system for a glider type exercise device that further reduces the stress on the user&#39;s body and the exercise apparatus when in operation provides a low impact simulation of walking and striding, including aggressive striding, and aerobic upper and lower body exercises. It is recognized that numerous changes to the described embodiment of the invention will be apparent to those skilled in the art without departing from its true spirit and scope. The invention is to be limited only as defined in the claims.
A glider device includes a pair of swingably mounted foot platforms pivotally supported by links at their heel ends. A spring cage, in one embodiment, includes a tension spring in each link to resiliently support the heel end of the foot platform. The spring cage limits displacement of the tension spring and includes a compression spring that cushions the displacement of the tension spring. In the a second, preferred embodiment, a stack of rubber bushings is supported in the spring cage and compress and decompress to provide a cushioning action to the foot platform.