referring now to the drawings and the embodiments illustrated therein , an exerciser or apparatus embodying the present invention is shown in the attached figures and is generally referred to as numeral 20 ( fig1 ). exerciser 20 includes an upright frame 22 upon which upper and lower mechanisms 24 and 26 , respectively , are supported . a motor 28 operates primary endless drive chain 30 and secondary endless drive chain 32 to drive mechanisms 24 and 26 at a coordinated and variable speed ( fig4 ). upright frame 22 ( fig1 and 4 ) is a rigid framework constructed of tubular beams for strength . frame 22 includes a planar base 34 made of two side members 36 and front and rear cross members 40 , 42 which are interconnected to form a rigid support structure . side members 36 have protruding portions 44 that extend forward of front cross member 40 . primary side upright members 48 , 50 attach to the forward end of protruding portions 44 and extend diagonally upwardly and rearwardly a vertical distance above the height of a typical person and at a angle which promotes the comfortable operation of exerciser 20 , as discussed below . a pair of support beams 52 extend between side members 36 of base 34 and upright members 48 , 50 to rigidly fix the angular position of upright members 48 , 50 . a rearwardly offset middle cross member 56 and a top cross member 58 rigidly interconnect upright members 48 , 50 to complete the rigid frame . upper mechanism 24 includes upper and lower axles 60 and 62 which extend horizontally between upright members 48 , 50 and attach to upright members 48 , 50 for rotational movement within bearings 64 , 66 , 68 and 70 . bearings 64 , 66 , 68 and 70 may attach to the front of upright members 48 , 50 to facilitate assembly and to establish a proper angle for mechanism 24 , but alternative designs are possible . upper bearings 64 and 66 are slideably adjustable by adjustment mechanisms 65 and 67 on upright members 48 , 50 so that endless chains 72 , 74 which extend between axles 60 , 62 on sprockets 76 , 78 , 80 and 82 can be properly tightened . lower axle 62 further includes a secondary drive chain 32 ( fig4 ) for powering upper mechanism 24 . a safety shield 92 is positioned between upright members 48 , 50 and between axles 60 and 62 ( fig1 ). it is contemplated that shield 92 will include upper and lower portions 93 that cover axles 60 , 62 , although several alternative arrangements are possible . for example , lower axle 62 could be constructed with a split shaft so that the central area is entirely open ( i . e . similar to axles 98 and 100 of lower mechanism 26 ). side shields 94 ( fig1 ) are positioned around the front of endless chains 72 , 74 as they extend along the useful segment of the path of rungs 88 to protect against accidental rubbing or contacting of chains 72 , 74 . these shields increase both the safety and aesthetics of upper mechanism 24 . hand supports or rungs 88 attach between endless chains 72 , 74 by use of brackets 90 ( fig7 ). rungs 88 have a diameter which is conducive for grasping by the hands of an operator . sprockets 76 , 78 , 80 and 82 are properly sized so that endless chains 72 , 74 and specifically rungs 88 have a clearance for an operator &# 39 ; s fingers between them and shield 92 as rungs 88 traverse downwardly in front of shield 92 . rungs 88 establish a path as they travel in an oblong pattern diagonally downwardly from axle 60 to axle 62 in front of shield 92 during a useful segment , around lower axle 62 , upwardly behind shield 92 , and around upper axle 60 . in the preferred embodiment , six to eight round rungs are used , although it is contemplated that various numbers and shapes of rungs can be used . lower mechanism 26 is adapted for use with an operator &# 39 ; s lower body . lower mechanism 26 includes an upper axle 96 and right and left lower axles 98 and 100 . upper axle 96 extends horizontally between and is rotationally mounted within bearings 102 , 104 , which are adjustably mounted on the backside of upright members 48 , 50 as shown . bearings 102 and 104 are slideably adjustable by adjustment mechanisms 103 and 105 . lower axles 98 and 100 are axially aligned and rotationally mounted within bearings 103 , 105 which are mounted on upright members 48 , 50 near a lower end thereof . by mounting upper axle 96 on the backside of upright members 48 , 50 and lower axles 98 , 100 on the front side thereof , lower mechanism 26 is oriented at a smaller angle from horizontal than upper mechanism 24 . thus , lower mechanism 24 is better adapted for use by the operator &# 39 ; s lower body , as discussed below . it is contemplated that lower axles 98 and 100 will be foreshortened to leave an open area between them to eliminate an area that may serve to bruise the operators ankles . endless chains 106 and 108 extend around sprockets 110 , 112 , 114 and 116 located on axles 96 , 98 and 100 , and can be tightened by movement of slideably adjustable bearings 102 , 104 on upright members 48 , 50 . sprockets 110 , 112 , 114 , and 116 of lower mechanism 26 are larger than sprockets 76 , 78 , 80 , and 82 of upper mechanism 24 to facilitate movement of platforms 118 around lower mechanism 26 . foot supports or platforms 118 extend horizontally between and attach to endless chains 106 , 108 by use of brackets 90 . an angle iron 122 extends between brackets 90 and attaches under platforms 118 to properly horizontally orient the upper surface 124 of platforms 118 during its useful segment of movement 123 . platforms 118 establish a path as they travel in an oblong pattern diagonally downwardly from upper axle 96 , around aligned lower axles 98 and 100 , upwardly toward upper axle 96 , and around axle 96 . it is contemplated that platforms 118 can be made of several different materials , but in the preferred embodiment will be made of a reinforced plastic material . flexible sheets 126 are attached to the bottom 125 of and between platforms 118 to form a barrier to the operators feet and legs to prevent them from entering the area between and behind platforms 118 during their movement through the useful segment 123 of their path ( fig6 ). sheets 126 also improve aesthetics by closing off the area behind lower mechanism 24 . sheets 126 flexes and folds as needed as platforms 118 move around lower mechanism 24 . during the diagonal downward movement of platforms 118 , sheets 126 are stretched tightly enough to reduce the chance of objects being put into and between platforms , but loosely enough to prevent binding of endless chains 106 , 108 . it is contemplated that sheets 126 could be replaced with a hinged configuration such as is often used in escalators . inner side shields 128 ( fig1 ) cover endless chains 106 , 108 along the forward edge of upright members 48 , 50 to protect against rubbing or contacting of chains 106 , 108 . these shields increase both safety and aesthetics . lower mechanism 26 is positioned at a smaller angle to horizontal than upper mechanism 24 so that lower mechanism 26 provides clearance for the knees of a user during the useful segment of travel by platforms 118 along their respective path . in the preferred embodiment , this angle is between about 45 ° and 60 °, which is similar to the rise of steps in bleachers and the like . the angle of upper mechanism 22 to horizontal is between about 60 and 75 °, which is similar to the angle of a ladder propped against a wall . it is contemplated that various angles can be used , and also that exerciser 20 can be made to allow adjustment of the angles as desired , by adjusting the angle of the base relative to the floor , or support surface , or by shimming any of the bearings inwardly or outwardly such as is shown by arrows a and b in fig4 . a powering mechanism includes a motor 28 fastened to base 34 . in the embodiment shown , motor 28 is a dc motor which drives a worm - gear speed reduction device 13 which rotates a drive sprocket 134 . motor 28 is a variable speed 1 / 3 hp dc motor operating at 1750 rpm . speed reduction device 132 is a worm - gear reducer operating at 30 : 1 reduction rate , while sprockets 134 , 138 , 140 and other sprockets on upper and lower mechanisms 24 , 26 are matched and sized to achieve the speed desired . a one - way friction clutch 133 attached to device 132 prevents the weight of a person on the exerciser from driving the platforms 118 and motor 28 at a speed faster than is desired . an endless primary drive chain 30 extends from sprocket 134 to sprocket 138 and drives axle 96 . motor 28 is adjustably positionable to tighten chain 30 . in addition to driving lower mechanism 24 , axle 96 supports a drive sprocket 140 and endless secondary drive chain 32 operably connected to drive axle 62 . a tensioning device 144 attached to upright member 50 maintains the necessary tension on endless chain 32 . similar tensioning devices could be used on the other endless chains as may be required . a control panel 146 is mounted to one side of upper mechanism 22 on brackets 148 at a convenient height for use by an operator positioned on exerciser 20 . the control panel 146 shown , houses a control circuit 147 ( fig8 ) including an on / off switch 150 , a variable speed control 152 , and a timer 154 . speed control 152 is a rheostat which cooperates with dc motor 28 to controllably vary the speed of rungs 88 and platforms 118 . timer 154 allows a person using exerciser 20 to time their workout . it is contemplated that control panel 146 could include various readouts and mechanisms ( not shown ) such for measuring speed , pulse rate , calories burned , and the like . it is also contemplated that a programmable device 156 could be used to preset an exercise routine such as a warm - up speed for a few minutes , a faster intermediate speed for several minutes , and a warm - down speed . having described the components and parts of the preferred embodiment of the exerciser , its use and operation should be obvious to one skilled in the art . briefly , exerciser 20 is positioned in a convenient location and is plugged into an electrical outlet . an operator desiring to use exerciser 20 first makes sure the unit is turned off , the variable speed is turned to a slow speed , and the rungs 88 and platforms 118 are not moving . the operator then steps onto a platform 118 and grasps a rung 88 . the on / off switch 150 is flipped to the &# 34 ; on &# 34 ; position , and variable speed control 152 is rotated until rungs 88 and platforms 118 begin to move . the operator begins to grasp successive rungs 88 in a hand - over - hand motion as the rungs are presented in front of the operator , and simultaneously begins to step on successive platforms 118 also presented in below the operator . since both the arms and legs of the operator are active , the operator &# 39 ; s body is in &# 34 ; total suspension &# 34 ; such that the operator cannot become lazy or &# 34 ; cheat &# 34 ; by supporting part of their weight on a safety rail or other devices . at the same time , the operator is in control and need not fear falling since both the hands and feet can be actively used to stay in a balanced position . further , since the operator &# 39 ; s arms and legs are used , the exercise provided is a full body exercise which is aerobically balanced . if the operator desires a more vigorous pace , the speed of rungs 88 and platforms 118 are increased by use of variable speed control 152 . also , timer 154 indicates the length of time remaining in the workout . if an operator should stumble or not keep up , shields 92 , 94 , 128 and flexible sheets 126 help reduce the risk of undesirable entanglement with rungs 88 and platforms 118 . additionally , shield 92 is designed with a blunted lower end 93 ( fig1 ) which tends to gently force an operator &# 39 ; s wrist off of rungs 88 as rungs 88 move around axle 62 from the front to the rear , thus causing the operator to release their grasp of rungs 88 during this movement . platforms 118 also tend to tip as they round lower axle 98 , which deposits the operator onto the floor is the operator does not move to the next platform in time . in a first alternative embodiment , an exerciser 20 &# 39 ; includes one or more photocells 156 ( fig9 ). photocells 156 could be positioned at the lower end of upper or lower mechanisms 24 , 26 to sense if the operator is falling behind and is therefore lower on exerciser 20 than is desired . photocell 156 could be electrically connected to slow down or turn off the exerciser depending upon safety devices utilized or deemed necessary . it is contemplated that photocells 156 could also be placed in other positions . in a second alternative embodiment , an exerciser 20 &# 34 ; includes a pair of hinges 158 ( fig1 ) between upper 10 and lower portions of upright members 48 , 50 . hinges 158 would be positioned on the front side of upright members 48 , 50 so that upper mechanism 22 could be folded forwardly onto lower mechanism 24 in a compact arrangement for shipping . when ready for use , lower mechanism 24 would be tipped upwardly into position and locked rigidly in place by latches 162 on the backside of upright members 48 , 50 . endless chain 32 would then be installed between drive sprocket 140 and axle 62 to ready exerciser 20 for use . changes and modifications in the specifically described embodiment can be carried out without departing from the principals of the invention , which is intended to be limited only by the scope of the appended claims , as interpreted according to the principals of patent law including the doctrine of equivalents .
an exerciser provides low impact exercise for the upper and lower body of an operator . the apparatus includes an upper portion having moving rungs simulating a hand - over - hand motion to exercise one &# 39 ; s upper body and a lower portion having moving platforms simulating a stair - like climbing motion to exercise one &# 39 ; s lower body . the upper and lower portions are oriented at different angles to maximize user comfort , the angle of the lower portion in particular providing clearance for one &# 39 ; s knees during use . the exerciser also includes a variable speed control to adjustable vary the speed of the moving rungs and platforms , thereby adapting to the needs of various users .