Patent Publication Number: US-5256124-A

Title: Body exerciser using distributed frictional brake means and central acting biasing means

Description:
RELATED APPLICATION 
     This application is a continuation-in-part of the following application Ser. No. 07/668,591 filed Mar. 13, 1991 for &#34;BODY EXERCISER USING MULTI-SURFACED, DISTRIBUTED FRICTIONAL BRAKE MEANS&#34; now U.S. Pat. No. 5,158,519 issued Oct. 22, 1992 
    
    
     In the parent application, two cranks are journaled from opposite directions into independently operating friction brakes, all operationally secured within a central housing. The friction brakes of each crank are adjusted as to friction bias, by a common frictional biasing means that includes an activation rod that extends exterior of the housing. But since the rod is disposed coaxial of the axes of rotation of the assembly, it must extend through the hub of one of the crank. In addition, in such position, the rod can be fitted with a handle which is positioned adjacent to the plane of rotation of the crank handle. In such position, the rod handle has been found to sometimes interfere with the user&#39;s arms as the cranks are worked. 
     SCOPE OF THE INVENTION 
     The present invention relates to body exercisers and more particularly to methods and means for exercising large muscles of a person in tandem or independently using such exercisers wherein resistance to movement of separately liftable and retractable cranks of such exercisers is provided by independently operating friction brakes interconnected by a centrally positioned friction biasing means. In one aspect, biasing pressure for the frictional brakes is provided by a bi-directionally acting, calibrating angled wedge block connected to an activating rod having an axis of rotation perpendicular to the axes of rotation of the cranks, such rod having a handle that extends exteriorly of the central housing midway between but in non-interfering contact with the operation of the cranks. 
     BACKGROUND OF THE INVENTION 
     In my application referenced above, two cranks are journaled from opposite directions into independently operating friction brakes, all operationally secured within a central housing. The friction brakes of each crank are adjusted as to friction bias, by a common frictional biasing means that includes an activation rod that extends exterior of the housing. But since the rod is disposed coaxial of the axes of rotation of the assembly, it must extend through the hub of one of the crank. In addition, in such extension position, the rod can be fitted with a handle which is positioned adjacent to the plane of rotation of the crank handle. In such position, the rod handle has been found to sometimes interfere with one of the user&#39;s arms as the cranks are worked. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, an exerciser is described which comprises a simple structure composed of a paucity of elements which can be readily assembled while at the same time can generate a surprisingly large, distributed resistance load (say up to 350 pounds at conventional lifting lengths) without using pulley-or cable-pressure whereby the user&#39;s limbs can be worked in both push-pull, pull only or push only replications. The exerciser comprises essentially two cranks journaled from opposite directions into independently operating friction brakes for like-independent operation of the cranks by the user. The friction brakes of each crank--while independently operatable--are interconnected by a central located friction biasing means housed within a horizontally extending, central housing. The biasing means includes an activation rod. The rod has a handle that extends exterior of the housing midway between the cranks. The biasing means generates biasing pressure via a centrally disposed wedge block attached to the rod. The wedge block includes slanted, opposed side surfaces. They contact opposed slanted end surfaces of a pair of push blocks. In operation, transverse movement of the wedge block (in response to rotation of the rod) normal to the longitudinal axis of symmetry of the central housing, causes longitudinal wedging movement of the push blocks against the stationary and rotational members of the friction brakes relative to fixed end blocks of the housing. Since each friction brake also includes a series of stackable, laterally slidable rotatable and stationary members, such squeezing pressure brings all broad vertical surfaces of these members into frictional contact--sandwich style--with each other. 
     During the exercise session, the friction biasing means of the invention generates squeezing forces at the push block in a rapid manner since transverse, rectilinear movement of the wedge block is multiplied by a factor of two at the oppositely slanted end surfaces of the push blocks. Source of such bi-directional movement is the opposite angled working surfaces of the wedge block against the end surfaces of the push blocks. Furthermore, if the housing is slotted in the vicinity of the wedge block, the rectilinear movement of the latter can also be used as an indicator of magnitude of resistance loading. In order to aid in the indication process, resistance loading values are marked on an exteriorly viewable scale adjacent to the slot through which an indication pointer operatively attached to the wedge block is viewed. 
     From the preceding discussion, it is seen that the invention has as its objects, inter alia, the provision of an improved exerciser composed of few and simple elements which can be assembled easily at low cost but which has versatility wherein large resistance loads to movement via one or the other crank arms can be generated whereby the larger muscles of the user can be worked in both push-pull, pull only or push only replications. Other objects of the invention will become apparent from the following more detailed description and accompanying drawings in which: 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 and 2 are side and front elevational views of the exerciser of the invention partially exploded to illustrate various handle configurations attachable to two cranks journaled from opposite directions into a central housing that is affixed to a permanent support structure, such as an exercise bench; 
     FIG. 3 is an enlarged section taken along line 3--3 of FIG. 2 to illustrate friction braking means and a friction biasing means in more detail, each braking means including a series of rotatable and stationary members having broad frictional contact, the rotatable members attached to and rotatable with the cranks about a common axis of rotation but having bi-directional biasing pressure applied thereto via the mid-located friction biasing means, the latter including a transversely movable wedge block attached to an activation rod having an axis of symmetry normal to the axes of rotation of the crank arms, the wedge block having oppositely sloped surfaces in sliding contact with oppositely slanted end surfaces of a pair of push blocks at the ends of the rotatable and stationary members of the braking means, such biasing pressure being provided by the transverse movement of the wedge block being translated into longitudinal movement of the push blocks against the braking members and thence against fixed end walls of the central housing; 
     FIG. 4 is a detail side view of a portion of the central housing of FIGS. 1-3 in the vicinity of the centrally positioned friction biasing means illustrating how the amount of friction force being applied to the crank arms is indicated to the user; 
     FIG. 5 is a detail end view of the crank arm exiting from one of the fixed end blocks of the central housing of FIG. 2; 
     FIGS. 6 and 7 are front elevational and side detail views, respectively, of a rotatable member of each braking means of FIG. 3; 
     FIGS. 8 and 9 are front elevational and side detail views, respectively, of a stationary member of each braking means of FIG. 3; 
     FIGS. 10 and 11 are front elevational and detail side views, respectively, of one of the pair of push blocks of FIG. 3; 
     FIGS. 12 and 13 are front elevational and detail side views, respectively, of an end block of the housing of FIG. 3; 
     FIGS. 14 and 15 are front elevational and side detail views, respectively, of each crank arm including ratcheting means therefor; 
     FIGS. 16 and 17 are front elevational and side detail views, respectively, of the wedge block of the biasing means of FIG. 3. 
    
    
     PREFERRED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 
     FIGS. 1 and 2 are side and front views of the exerciser 2 of the invention. The exerciser 2 comprises a simple structure composed of elements which can be readily assembled while at the same time can generate a large resistance load without using pulley- or cable-pressure. In that way the larger muscles of the user can be worked in both push-pull, pull only or push only replications. 
     In more detail, the exerciser 2 is comprised essentially of two cranks 8a, 8b and independently operating friction means 9 (see FIG. 2) housed within a central housing 10. Each crank 8a, 8b is L-shaped and comprises a forearm 5, a lateral arm 6 and ratcheting mechanism 4. The forearm 5 and lateral arm 6 are interconnected via the rachet mechanism 4. The forearm 5 includes an end 11 remote from the central housing 10 connectable to a series of action arms generally indicated at 14 to permit different muscles of the user to be worked. For example, (i) an L-shaped arm-handle 14a is shown and is used for arm lifts, arms curls and arm stretches above a floor 15 using a goose-necked attachment 16 attached to an exercise bench 17 composed of flat support 18a, legs 18b, plastic ticking 19a and cover 19b overlaying the support 18a, the attachment 16 extending over a portion of the horizontal extent of bench 17. Note in the embodiment of item (i) that handle 14a&#39; is parallel to the floor 15 and is operated either over limited arcuate ranges, say 90 degrees or over a full 360 degree rotation; and (ii) a second embodiment in which leg brackets 14b (shown in FIGS. 1 and 2 in phantom line) are located below the exercise bench 17) and are operated over limited arcuate ranges for leg extensions and curls. However, it should be noted that a separate L-shaped arm-handle could be added to the above-disclosed embodiments without undue experimentation, e.g., adjacent to a seat of an automobile in which the handle is perpendicular to the floor to emulate a gear-shift lever of a race car. 
     A separate lateral arm 6 of each crank 8a, 8b has a major portion (not shown) positioned within the central housing 10, such portion extending therein from an opposite direction indicated by arrows 1, 3. The ends of the arms 6 are journaled interior of the friction braking means 9 within the central housing 10 as explained below. 
     FIG. 3 shows the friction braking means 9 in more detail. 
     As shown, the friction braking means 9 is housed interiorly of upright side walls 21 of central housing 10. Relative to either horizontal axis of symmetry 23 of the housing 10 or with regard to a vertical plane of action A1--A1 that bisects friction biasing means 20 of the invention, the side walls 21 are of square cross section. Thus, along the axis of symmetry 23, different sectioned elements of the braking means 9 can be given the capability of rotation about such axis 23 merely because of their shape relative to that of the lateral arm 6. 
     For example, the braking means 9 includes a first group of members generally indicated at 25 offset in the longitudinal direction relative to the action plane A1--A1. (A second group of members identical to the first group 25 is offset from the action plane A1--A1 but is not shown in the interest of brevity since description of one suffices for the other.) The first and second groups are associated with independent movement of the lateral arms 6 about the axis of symmetry 23. 
     The group 25 includes a series of interiorly disposed rotatable members 26 and stationary members 27. In this regard, the group 25 is subdivided into sets, each set comprising a rotating member 26 and a pair of stationary members 27 in side-by-side sandwich contact along broad surfaces 28 parallel to the vertical plane of action A1--A1. Each set defines a finite length and together form a distributed loading so as to provide a distributed loading that smoothly resists the rotation of the arms 6. In this regard at least 6-10 separate sets are needed to act in concert relative to movement of each arm 6 while 7-9 sets per group are preferred. Of course, the function of broad contact between the members 26, 27 is to provide a smooth resistance to rotary movement of the lateral arms 6. In this regard, the stationary members 27 are covered with a material to provide smooth braking action and as previously mentioned, are positioned--sandwich style--about the rotatable members 26 to resist movement of the latter in concert with rotation of the lateral arms 6 about axis of symmetry 23. 
     Within each set, the rotating member 26 is operatively positioned about the lateral arm 6 in the manner shown in FIG. 5. As shown, the rotating member 26 is annularly shaped and includes a central opening 24 of square cross section defining an axis of symmetry coincident with axis of symmetry 23 of the housing. Because the central opening 24 of the rotating member 26 is constructed to have full edge contact with side wall 29 of the arm 6, the member 26 rotates in concert with lateral arm 6 about an axis of rotation coincident with the axis of symmetry 23. 
     Still referring to FIG. 5, the stationary members 27 each include a central opening 30 of circular cross section defining a diameter D having a center of formation coincident with the axis of symmetry 23. Note in this regard that central opening 30 is larger than imaginary circle 33 generated by the rotation of corners 34 of the lateral arm 6 about axis of symmetry 23. Each stationary member 27 also has a large transverse length that places such member 27 in direct contact with the central housing 10 as explained below. Note further that since the distribution of the sets of members 26, 27 must be such that the broad surfaces 28 of each are placed side-by-side sandwich contact with adjacent members, the members 26, 27 are formed into a single integrated unit operating in response to rotation of arm 6 about axis of symmetry 23. 
     Returning to FIG. 3, note that at the interior ends of the unitary combination of members 26, 27 described above are provided by a pair of push blocks 36, 37. And alternately, the exterior ends of such unitary combination of members 26, 27 are provided by end blocks 22 (see FIG. 2) attached to the central housing 10 by screws. 
     Returning to FIG. 3, changes in braking power are easily achieved via friction biasing means 20. It comprises a threaded rod 29 having an axis of rotation coincident with action plane A1--A1 and normal to the axis of symmetry 23 of the central housing 10, and generates simultaneous bi-directional movement of the member groups including group 25 relative to the vertical plane A1--A1. That is, the friction biasing means 20 permits longitudinal adjustment--in opposite directions--of push blocks 36, 37 relative to the end blocks 22 (see FIG. 2) fixed to the central housing 10. Since the push blocks 36, 37 are movable, they can bring members 26, 27 into squeezing contact with each other against the fixed end blocks 22. 
     In detail, note that threaded rod 29 attaches to a handle 31 that is also bisected by vertical action plane A1--A1. The handle 31 includes a hub 32 having a threaded cavity (not shown) into which rod 29 is threadably inserted. At its opposite end 35, the rod 29 extends through and into a central wedge block 38. The wedge block 38 includes a central cavity 39 having a side wall 40 that is slightly larger in diameter than that of the rod 29. At end wall 41, the side wall 40 is enlarged to form end cavity 42 into which nut 43 is fixedly placed. The nut 43 also has a threaded side wall to engage the threads of the rod 29. As shown, the wedge block 38 includes parallel top and bottom surfaces 44, 45 and non-parallel side walls 46, 47 slanted toward the handle 31. 
     As shown in FIGS. 16 and 17, the non-parallel walls 46, 47 of the wedge block 38 are seen not to intersect the top and bottom surfaces 44, 45 at 90 degrees. Instead, the side surfaces 46, 47 slant whereby the included angle B between the bottom wall 45 and the side walls 46, 47 is greater than 90 degrees while included angle C between the top wall 44 and the side walls 46, 47 is less than 90 degrees. Since such pairs of like included angles are equal to each other, i.e., angle B=angle B and angle C=angle C, the slanted side walls 46, 47 define planes 48, 49 which intersect the action plane A1--A1 at point P. Also intersecting one or the other of the planes 48, 49 is a series of discs 50a, 50b and 51a, 51b. The discs 50a, 50b and 51a, 51b are constructed of a low friction material such as Teflon, a trademark of DuPont. The discs 50a, 50b attach to side wall 46 at a common height relative to bottom wall 45, and the discs, 51a, 51b attach to side wall 47 at the same common height. Functions of the discs 50a, 50b and 51a, 51b: limit the application of squeezing forces over a highly accurate and easily repeatable application area vis-a-vis the push blocks 36, 37 of FIG. 3. 
     As shown in FIG. 17, the wedge block 38 also includes front and back walls 52, 53 which are parallel to each other and normal to top and bottom walls 44, 45. Note that the front and back walls 52, 53 are constructed such that they snugly fit within and in contact with the side walls of the central housing 10. Hence movement of the wedge block 38 in the transverse direction as indicated by arrow 54 (FIG. 3) is prevented. 
     Note that cross sections of the wedge block 38 taken in directions right angles to each other define tetragonals of different classes. The transverse and vertical cross sections, for example, are rectangular, while the longitudinal cross section is rhomboidal. 
     During adjustment as indicated in FIG. 3, the rod 29 is rotated relative to wedge block 38 which because of its mode of connection via the nut 43, converts rotatory movement into rectilinear travel of the wedge block 38 coincident with the action plane A1--A1. The direction of rectilinear movement is a function of clockwise or counterclock rotation of the rod 29. The wedge block 38 is prevented from rotation due to close proximity to the side walls 21 of the housing 10 (see FIG. 3) in the transverse direction indicated by arrow 54. In the longitudinal direction indicated by arrow 55, the slanting side walls 46, 47 wedge against oppositely slanted back walls 56 of the push blocks 36, 37. As the wedge block 38 is provided with a particular direction of rectilinear movement, say in the direction of arrow 57, such movement is translated in longitudinal movement of the pair of push block 36, 37 thereby increasing the braking load on all sets of members 26, 27. This loading is reflected in increased resistance to rotation of the lateral arms 6. 
     That is, the force required to rotate each lateral arm 6 is evenly distributed within the member groups 25. After the push blocks 36, 37; member groups 25 and the end blocks 22 of the housing 10 (FIG. 2) become welded together into a single unit, angular movement of the lateral arms 6 (and hence movement of the rotatable members 26 relative to stationary member 27) is directly related to the force needed to rotate one or both of the arms 6 about the axis of symmetry 23. 
     Furthermore, if one of the side walls 21 of the housing 10 is provided with a slot 60 (see FIG. 4) in the vicinity of the wedge block 38, the rectilinear movement of the block 38 can be indicated as an indicator of magnitude of resistance loading of the friction braking means 9. In order to aid in the indication process as shown in FIG. 4, resistance loading indicia 61 are marked on an exteriorly viewable scale 62 adjacent to the slot 60. A pointer 63 is pivotally attached to the wedge block 38 and includes a central pivot pin 64 adjacent to the slot 60 wherein angular movement of the pointer 63 relative to the scale 62 indicates brake loading of the friction braking means 9. 
     FIGS. 6 and 7 are front elevational and side detail views, respectively, of a rotatable member 26 of FIG. 3 showing the latter in more detail. 
     As shown, the rotatable member 26 has the central opening 24 previously mentioned in regard to FIG. 5. It is of square cross section to snugly fit over and attach to the arm 6 of FIG. 3. Such opening 24 is defined by a side wall 65. At the circumferential outer surface of side wall 65 is circumferential surface 66; but note that the side wall 65 in constructed in three plys, viz., a metallic central support 67 sandwiched between disc members 28a. The latter provide the transversely extending broad surfaces 28 for the rotatable member 26 for functioning in the manner previously described. While the central support 67 is preferably constructed of steel, the disc members 28a are preferably constructed of a plastic material such as Teflon, a trademark of DuPont Company, such disc members 28a contributing to the smooth braking resistance to rotation previously mentioned. Note the transverse position of the broad surfaces 28: extending from opening 24 to the circumferential surface 66. Also as previously mentioned, the opening 24 is sized to fit at the exterior surface of the lateral arm 6 of FIG. 5 so that action is in concert. The diameter D1 defined by circumferential surface 66 is less that the distance between opposed side walls of the central housing 10 so that as rotation of the former occurs, interference with the latter cannot occur, see FIG. 5. 
     FIGS. 8 and 9 are front elevational and side detail views, respectively, of a stationary member 27 of FIG. 3. 
     As shown, the stationary member 27 includes the broad surfaces 28 previously mentioned, placed in contact with like surfaces of the rotatable member 26 (viz., into contact with Teflon discs 28a of FIG. 7). The result is an unexpected effect by which braking resistance can be generated between these members. In this regard, the stationary member 27 is constructed in a single ply of material such as polypropylene, (see FIG. 9). While any plastic material may be employed, it has been found that the most advantageous is polypropylene because the latter provides excellent braking resistance, and at the same time the polypropylene does not fuse under lateral pressure with the Teflon discs 28a of the rotatory member 26. 
     The stationary member 27 includes a side wall 70 and interior opening 30 of circular cross section of diameter D. The significance of the diameter D as occurring with reference to FIGS. 3 and 5, has been previously discussed. 
     In the radial direction from the opening 30, the side wall 70 has outer termini. These outer termini are seen to include separate horizontal surfaces 71 at right angles to vertical surfaces 72. The surfaces 71, 72 define a square transverse cross section for the side wall 70. At right angles to the surfaces 71, 72 are the broad surfaces 28 by which braking resistance to rotation is obtained as previously explained. 
     Note the position of the broad surfaces 28: between the opening 30 and the terminating surfaces 71, 72. Also as previously mentioned, the opening 30 is sized to clear rotation of lateral arm 6 about the axis of symmetry 23 of FIG. 5. 
     FIGS. 10 and 11 are front elevational and side detail views, respectively, of push blocks 36, 37 of FIG. 3. 
     As shown, each push block 36, 37 includes the slanted end surface 56 opposite in slant to the surfaces 46, 47 of the wedge block 38 (FIG. 3) previously mentioned. Each push block 36, 37 includes a central cavity 75 of circular cross section that terminates adjacent to its slanted end surface 56. The central cavity 75 defines a side lip 76 having terminating lateral cavity 75 defines a side lip 78 having a terminating lateral surface 77 that is placed in contact with the broad surface 28 (see FIG. 3) of the adjacently positioned stationary member 27. Within the central cavity 75 is positioned a bushing 78 of pliant material. As shown best in FIG. 10, the bushing 78 includes a central opening 79 of square cross section and a circumferential edge 80. Within the central opening 79 of the bushing 77 the lateral arm 6 of FIG. 3 can be journaled. With rotation of the latter, such pliant bushing 78 also rotates about the axis of symmetry of the central housing 10 as previously mentioned, while the push block 36 or 37 remains stationary. The pliant bushing 78 is also provided with annular side wall 81 to more easily accommodate such rotation without bushing breakdown. The bushing 78 is preferably formed of a material of low frictional coefficient. In this regard, any low frictional material may be employed, but the most advantageous has been found to be plastic because the latter provides excellent lubricating characteristics and at the same time the plastic does not fuse together under pressure. 
     FIGS. 12 and 13 are front elevational and side detail views, respectively, of end blocks 22 of FIG. 3. 
     As shown, each block 22 includes first and second broad surface 85. After assembly, one such broad surface 85 is placed in contact with the surfaces 28 of a stationary member 27 as previously explained. Each end block 22 has an interior opening 86 of circular cross section defining a side wall 87 that is enlarged at shoulder 87a to define a larger cavity 87b into which a pliant bushing 88 is inserted. The pliant bushing 88 is provided with an opening 89 that is square in cross section into which the lateral arm 6 of FIG. 3 can be journaled. With rotation of the latter, such pliant bushing 89 also rotates, while the end block 22 remains stationary. The pliant bushing 89 is formed of a material of low frictional coefficient. In this regard, any, low frictional material may be employed, but the most advantageous has been found to be plastic because the latter provides excellent lubricating characteristics and at the same time the plastic does not fuse under pressure. 
     FIGS. 14 and 15 are front elevational and side detail views, respectively, of a crank 8a or 8b in combination with the ratchet mechanism 4 of FIGS. 1-3. 
     Each crank 8a, 8b is L-shaped and comprises forearm 5 and a lateral arm 6, the forearm 5 and lateral arm 6 being interconnected via the rachet mechanism 4. The forearm 5 includes an end 11 remote from the central housing 10 that is connectable to one of a series of action arms--separately--such as a L-shaped arm-handle 14a used for arm lifts, arms curls and arm stretches that can be operated over limited arcuate ranges, say 90 degrees to full 360 degrees rotation. 
     Each lateral arm 6 defines an axis of symmetry 90 coincident with the axis of symmetry of the housing 10 which permits the ratchet 4 including the forearm 5 and arm-handle 14a to rotate about axis 90 in limited or full 360 degree rotation. In this regard, the ratchet 4 is provided with a pair of tear-drop shaped plates 92, 93 sandwiching a central gear 94. Each plate 92, 93 is provided with a central opening 95 of diameter D2 defining a side wall 96 into which a pliant bushing 97 is inserted. The pliant bushing 97 is also provided with an opening 98 that is square in cross section matched in shape and dimensions to those of lateral arm 6 so as to fixedly receive same. The gear 94 is also provided with an opening 99 that is square in cross section also matched in shape and dimensions to those of the lateral arm 6. But note that when the plates 92, 93 are rotated by forearm 5, each pliant bushing 97 of each plate 92, 93 also rotates about the axis 90, while the lateral arm 6 remains stationary assuming the gear 94 is not ratchetly engaged. But when the gear 94 is ratchetly attached to the plates 92, 93 via engagement of pawls 100 and 101 with the gear 94, rotation of the plates 92, 93 and gear 94 cause rotation of the lateral arm 6. Note in FIG. 14 that the pawls 100, 101 are rotatable about pins 102, 103 but are kept in contact with the gear 94 via C-shaped spring 104. In order to dislodge one or other of the pawls 100, 101 from contact with the gear 84, the ratchet 4 of the invention is provided with a release trigger 106 pivotable about pin 107 to bring cam surface 108 thereof into contact with such pawl 100, 101. Thus with the release trigger 106 in the mid-position, the lateral arm 6 is rotated in concert with either clockwise or counter-clockwise movement of the forearm 5 so that the invention provides a super-set function of exercise. But if the release trigger 106 is rotated clockwise in FIG. 14, the cam 108 releases pawl 100 from the gear 94. Hence counter-clockwise rotation of forearm 5 and arm-handle 14a causes rotation of the lateral arm 6 but the arm 6 is stationary when the forearm 5 is rotated in clockwise direction in FIG. 14, the pawl 101 sliding over the gear 94. And if the release trigger 106 is rotated counter-clockwise in FIG. 14, the cam 108 releases pawl 101 from the gear 94. Hence clockwise rotation of forearm 5 and arm handle 14a causes rotation of the lateral arm 6 but the arm 6 is stationary when the forearm 5 is rotated in counter-clockwise direction in FIG. 14, the pawl 100 sliding over the gear 94. 
     The pliant bushing 97 is formed of a material of low frictional coefficient. In this regard, any low frictional material may be employed, but the most advantageous has been found to be plastic because the latter provides excellent lubricating characteristics and at the same time the plastic does not fuse under pressure. 
     Thus, the ratchet mechanism 4 of the invention permits the forearm 5 and arm-handle 14a to be operationally attached to the lateral arm 6 in a variety of operational modes, say both rotary directions about axis 90, in a clockwise direction only or in a counter-clockwise direction only. 
     The above description contains several specific embodiments of the invention. It is not intended that such be construed as limitations on the scope of the invention, but merely as examples of preferred embodiments. Persons skilled in the art can envision other obvious possible variations within the scope of the description. For example, various handle configurations can also be attached to the forearm 5 (via spring-driven pins 110 of FIGS. 14 and 15 that penetrate openings 111 after the handle 113 has been inserted interior of the forearm 5). Such operations permit the user to perform various pushing, pulling exercising for strengthening the arms, shoulders, back, legs, and other parts of the body, particularly for professional athletes including weight lifters, body builders, football, baseball and basketball players, golfers, and race car drivers. Hence the scope of the invention is to be determined by the appended claims and their legal equivalents.