Abstract:
A resistance system for fitness equipment includes a frame, a resistance source such as an elastic cord, coil or any other type of spring, weight, pneumatic or hydraulic cylinders. The resistance source is mounted to a resistance block with a load support. A support disk is provided that is movably mounted to the frame and adapted to enable selective engagement with the load support. A transmission member, including a pliable member such as a cable, belt or other member, is coupled to the resistance source. Movement of the support disk enables selective engagement of the resistance source. In this way one or more individual resistance sources can be selectively engaged or disengaged to vary the resistance to the user by actuation of a dial or other actuator as directed by the user.

Description:
CROSS-REFERENCE TO RELATED APPLICATION DATA 
     Priority is claimed under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60/929,990, filed on Jul. 20, 2007, which is incorporated by reference herein; this application is a continuation-in-part of application Ser. No. 12/146,068 filed on Jun. 25, 2008 also entitled “Resistance System for Fitness Equipment.” 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to fitness equipment and, more particularly, to a system for altering the resistance in an exercise device. 
     BACKGROUND OF THE INVENTION 
     Increased convenience and efficiency are hallmarks of value in many products. Fitness equipment is no different. Resistance type fitness equipment has repeatedly been shown to provide numerous benefits including increased bone density, increased lean tissue mass and also some cardiovascular benefits. A desirable aspect of fitness equipment is the ability to change the resistance. Users need to increase resistance as they progress in an exercise program thereby the machine must be able to provide a variability in resistance settings. Ease of use and the ability to quickly change resistance are important in that some exercise programs require resistance changes with minimal down time. General ease of operation is always desirable but in fitness equipment and especially resistance or strength equipment it is highly desirable. 
     It should therefore be appreciated that there is a need for an adjustable resistance setting device that allows for actuation of a dial or other actuation system to simply, easily and reliably change the resistance settings in an exercise device. The present invention fulfills this need and others. 
     SUMMARY OF THE INVENTION 
     The present invention provides a resistance system for fitness equipment. This includes a frame, a resistance source coupled to a resistance block, a support disk movably mounted to the frame and adapted to enable selective engagement with the resistance block. A carriage may be provided that is movably mounted to the frame and coupled to the resistance source and a transmission member with a first end coupled to the carriage and a second end adapted to be engaged by a user. The transmission member can be rigid or a pliable member and in one embodiment it may be coupled to a lower portion of the carriage. The second end of the transmission member may be engaged by the user directly as by use of a handle mounted to the end of the transmission member or indirectly as would be the case when the transmission member mounts to a secondary system such as a gearbox or other transmission, of which the user engages. In another embodiment of the invention the carriage may include a handle or other user interface so that the carriage is moved directly by the user. 
     The resistance source of the resistance system may be a device selected from the group including a weight block, an elastic cord, a spring, a pneumatic cylinder or a hydraulic cylinder. The resistance source may be a single element or comprised of a plurality of resistance elements. The plurality of resistance elements may include at least one element with the resistance capacity of twice that of another resistance element. The plurality of resistance elements may include an element with twice the resistance capacity relative to the lowest resistance capacity element and every other resistance element has twice the resistance capacity of the next lower capacity resistance element. 
     The resistance block of the resistance system for exercise may include a load support adapted to be received by a disk lip on the support disk. In addition, the resistance system may further include a plurality of support disks on a common shaft, the shaft rotatably mounted to the frame. 
     In another form of the invention a method of exercise is also disclosed. This method includes providing the device as stated above and the steps of moving the support disk to engage a resistance block with the support disk and then actuating the carriage with respect to the frame so as to displace a portion of the resistance source. This provides a resistance to movement of the carriage at the user interface. 
     For the purposes of summarizing the invention and the advantages achieved over the prior art, certain advantages of the invention have been described herein. Of course, it is to be understood that not necessarily all such advantages can be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention can be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following description of the preferred embodiments and drawings, the invention not being limited to any particular preferred embodiment(s) disclosed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings, in which: 
         FIG. 1  is an isometric front view of a base of an exercise device incorporating a resistance system in accordance with the present invention. 
         FIG. 2  is a detail of the top section of the base of an exercise device of  FIG. 1  along line  2 - 2 . 
         FIG. 3  is a front view of the base of the exercise device of  FIG. 1 . 
         FIG. 4  is a detail of the top portion of the device shown in  FIG. 3  along line  4 - 4 . 
         FIG. 5  is a front isometric view of the device of  FIG. 1  shown with the covers removed. 
         FIG. 6  is a detail of the top, center portion of the device shown in  FIG. 5  along line  6 - 6 . 
         FIG. 7  is a top view of the exercise device of  FIG. 1   
         FIG. 8  is a sectioned view of the exercise device in  FIG. 7  sectioned along line  8 - 8 . 
         FIG. 9  is an isometric view of the support disk assembly of the exercise device of  FIG. 1 . 
         FIG. 10  is an isometric view of a resistance block of the exercise device of  FIG. 1   
         FIG. 11  is a detail view of the top portion of the resistance block of  FIG. 10  along line  11 - 11 . 
         FIG. 12  is a front view of the dial knob of  FIG. 1 , with a dial face showing an example of the resistance settings. 
         FIG. 13  is an isometric front view of a variation of the exercise device of  FIG. 1  with the elastic cords removed and replaced with a weight system. 
         FIG. 14  is an isometric rear view of the exercise device of  FIG. 13 . 
         FIG. 15  is a front isometric view of the exercise device of  FIG. 13  shown in use when the system is actuated. 
         FIG. 16  is a rear isometric view of the exercise device shown in  FIG. 15  with the rear block cover in place. 
         FIG. 17  is a front isometric view of a variation of the exercise device shown in  FIG. 1  with a pin-in-disk system. 
         FIG. 18  is a detail view of the pin-in-disk system shown in  FIG. 17  along line  18 - 18 . 
         FIG. 19  is a detail view of a single disk and a modified resistance block as shown in  FIG. 18  along line  19 - 19 . 
         FIG. 20  is an isometric view of the pin-in-disk assembly as shown in  FIG. 17 . 
         FIG. 21  is a detail view of a portion of a disk shown in  FIG. 20  along line  21 - 21 . 
         FIG. 22  is a front isometric view of a modified resistance block adapted for use with the pin-in-disk system of  FIG. 17 . 
         FIG. 23  is a detail view of the top portion of the resistance block of  FIG. 22  along line  23 - 23 . 
         FIG. 24  is a break out isometric view of an embodiment of the invention in which the disk assembly is mounted on the movable carriage. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the figures, and particularly to  FIGS. 1-12 , there is shown a first embodiment of a base of an exercise device  20 . In this embodiment, device  20  includes a frame  22  and two rails  24 . The rails  24  enable proper tracking of the carriage  26  relative to the frame  22 . In this embodiment this is accomplished by four carriage rollers  28  mounted to each of four corners of the carriage  26  and rolling on the rails  24 . The specifics of this tracking system are not considered critical to the novelty of the invention. It is understood that this is one embodiment of this assembly but other methods such as linear bearings, linear slides and glide bushings could also be used without taking away from the spirit of the invention. 
     Two bearings  30  are supported on the frame  22  and more clearly shown in  FIGS. 2 and 4 . These bearings  30  provide a means for movable support of a support disk assembly  32  on the frame  22 . In this embodiment the support disk assembly  32  is comprised of five support disks, each with at least one disk lip  34 . A first disk  36  includes a plurality of disk lips  34  spaced about the perimeter of the disk  36 . The purpose of each disk lip  34  is to engage with a portion of a resistance block  38 . When the disk lip  34  engages a block lip  40 , that resistance block  38  is supported by the frame  22  through the support disk assembly  32 . A carriage  26  can be displaced down by applying tension to a cable  42 . A resistance against this movement is provided by resistance cords  44  secured to a resistance block  38 , in which the disk lip  34  and block lip  40  are engaged. Any resistance blocks  38  in which their respective disk lip  34  is not engaged with a block lip  40  will be allowed to freely move down with the carriage  26  when tension is placed on the cable  42 . The cords  44  that are not supported by a disk lip  34  will not be elongated and therefore not add any tension to the cable  42 , as can be also seen in  FIGS. 5 and 6 . 
     In  FIG. 3  a front view of the mechanism is shown. The support disk assembly  32  includes five disks, each with a corresponding resistance block  38  and cord. In this embodiment the resistance cords  44  are configured according to the formula: T N =(T N-1 )*2. As an example, if T 1 =F, then T 2 =T 1 *2 and T 3 =T 2 *2 and so on, where T 1  through T N  are the tensions generated by elastic properties of the associated cords  44 . The lowest tension (F) is represented by T 1 . Each higher tension is represented by the following higher numbers, in this case T 2 , T 3  through T 5 . Each higher resistance cord (T 2 , T 3 , etc) provides twice the tension of the cord of the preceding lower tension (i.e. T 3 =T 2 *2). This provides a system with 2 N  number of increments or (2 N −1) number of increments when not counting zero resistance, where “N” is the number of cords and the value of the increments is the value of T 1  (or F). For example, a four 
                                                           TABLE 1               T 1  (10 lbs)   T 2  (20 lbs)   T 3  (40 lbs)   T 4  (80 lbs)   Total Force                                —   —   —   —   0       10   —   —   —   10       —   20   —   —   20       10   20   —   —   30       —   —   40   —   40       10   —   40   —   50       —   20   40   —   60       10   20   40   —   70       —   —   —   80   80       10   —   —   80   90       —   20   —   80   100       10   20   —   80   110       —   —   40   80   120       10   —   40   80   130       —   20   40   80   140       10   20   40   80   150                    
cord system with 10 pounds as the first cord would have 15 increments (2 4 −1=15) or 16 increments counting zero. One example of the cords and loads are presented in Table 1.
 
     With every increase in the number of cords the total number (including zero tension) of load combinations doubles. With 5 cords there are 2 5  or 32 combinations. With six cords counting zero there are 2 6  or 64 combinations. Whatever increment value is chosen to start (T 1 ) will be the tension or force increment. For example if T 1 =5 pounds, then the range would be 0 to 75 pounds with four cords in this arrangement. If T 1 =20 pounds then the sixteen increments of resistance would be 0 to 300 pounds. By adding one 160 pound cord as the fifth (T 5 ) to the previously mentioned four cord system with ten pound increments, the range would be 0 to 310 pounds with thirty-two different settings in ten-pound increments. In the system as described, a great deal of variety and range in resistance can be achieved with a small number of resistance cords. This system is disclosed with resistance cords only, but the same system can be used with a number of resistance sources including weights, springs, pneumatic and hydraulic cylinders, or any spring material and configuration which allows for the storage of mechanical energy stretching, bending, twisting or other physical deformation. 
     The disks of the assembly  32  in  FIGS. 3 and 4  are positioned with the associated highest resistance cord  46  nearest the center of the carriage  26 . This is desirable in that it minimizes the load in the tracking system of the carriage  26  but is not mandatory to the function of the invention. The fifth disk  48  has a common shaft  50  with the first disk  36 . Likewise the second disk  52 , third disk  54  and fourth disk  56  are also continuous with the shaft  50 . A shaft gear  58  is also continuous with the shaft  50 , thereby movement of the shaft gear  58  results in rotation of the shaft  50  and all the disks ( 36 ,  48 ,  52 ,  54  and  56 ). In this embodiment a knob gear  60  is provided that drives the shaft gear  58 . This is done to allow access to the knob  82  at the front of the device  20 . The location and for that matter, the presence of the shaft gear  58  and knob gear  60  are not mandatory but provided here as one embodiment of the invention. Another embodiment eliminates the shaft gear  58  and knob gear  60  and may provide a knob  82  on one or both ends of the shaft  50 , so that the user may rotate the shaft  50  directly. In a comparable manner, a drive system such as an electric motor, may be attached directly to the shaft  50  or any gear  58 . In this way the shaft  50  can be actuated by the push of a button somewhere on the machine or even remotely by wired or wireless connection including radio frequency (RF), infrared or any other communication known in the art. Any method of rotating the disks ( 36 ,  48 ,  52 ,  54  and  56 ) can be used to accomplish selection of the desired resistance. 
     In this embodiment the resistance blocks  38  are similar in construction in each position and adjacent to each disk ( 36 ,  48 ,  52 ,  54  and  56 ). Each resistance block  38  is attached to a resistance cord. As previously noted, the heaviest cord  46  is associated with the fifth disk  48 . The lightest cord, cord one  62 , is associated with the first disk  36 , cord two  64  is associated with the second disk  52 , cord three  66  with the third disk  54  and cord four  68  with the fourth disk  56 . Each of the cords ( 46 ,  62 ,  64 ,  66  and  68 ) is secured to the carriage  26  at the bottom rail  70 . Orientation of the support disk assembly  32  provides selective engagement of any or all of the resistance blocks  38  and associated cords ( 46 ,  62 ,  64 ,  66  and  68 ) to the frame through the disks ( 36 ,  48 ,  52 ,  54  and  56 ). Power is transferred to the carriage  26  by the user through the cable  42 . In this embodiment the resistance block cover  72  provides additional movable support of the resistance blocks  38  as they are guided by the slots  74 . This is one of any number of structural elements that may be used to guide the blocks  38  as they travel relative to the frame  22 . 
     More detail of the device  20  is shown in  FIGS. 5 and 6  in which the resistance block covers  72  (front and back) have been removed. In this view, the carriage  26  is shown with the carriage recoil bar  76  positioned under the block rail  78  or any other portion of the resistance block  38 . When a resistance block  38  is not engaged with the associated disk ( 36 ,  48 ,  52 ,  54  or  56 ), that resistance block  38  will move down with the carriage  26  as actuated by the cable  42 . These non-engaged resistance blocks  38  will be supported by the carriage recoil bar  76  and therefore be moved back up to the disk assembly  32  when the tension is decreased from the cable  42  and the carriage moves back to its original or non-tensioned position. An optional recoil cord (not shown in this figure) may be used to pull the carriage back to the top (starting position as shown here) if no cords are used. 
     The engagement of the fifth disk  48  with the associated resistance block  38  is illustrated in  FIG. 6 . Each disk ( 36 ,  48 ,  52 ,  54  and  56 ) includes a disk lip  34  that enables selective engagement with the block lip  40  of the resistance block  38 . The disks ( 48 ,  56 , etc.) are moved in this embodiment by actuation of the knob  82 , which is mounted to the knob gear  60 . The knob gear  60  is in this embodiment is a beveled gear that mates with the shaft gear  58  that is continuous with the shaft  50 . Thereby actuation of the knob  82  in a clockwise direction  84  causes rotation of the support disk assembly  32  in a clockwise direction  86  when viewed from the right of the machine  20  as is indicated by the arrows ( 84  and  86 ). Rotation of the shaft  50 , and therefore the combination of disks ( 36 ,  48 ,  52 ,  54  and  56 ) such that any of the associated disk lips  34  engage with their respective block lips  40  of the resistance blocks  38 , that block  38  (or combination of multiple blocks  38 ) will have one end of the cord  44  that is secured to that particular block  38  fixed to the frame  22  by way of the disk assembly  32 . In this embodiment the cable  42  is coupled to the carriage  26  at the opposite end relative to the blocks  38 . Also secured to this end of the carriage  26 , are the end of the cords  44  which are opposite to the end of the cords  44  where the blocks  38  are located. The resistance to movement of the carriage  26  by way of the cable  42  is proportionate to which blocks  38 , and therefore which cords  44 , have their blocks  38  held by engagement with the disk assembly  32 . 
     A top view of the device  20  is shown in  FIG. 7  illustrating the position of the section line  8 - 8 . This partial section view is shown in  FIG. 8  with the resistance block covers  72  removed for clarity. In this view it can be seen that the resistance blocks  38  are selectively engaged with the disks ( 36 ,  52 ,  48 ,  56  and  54 ), which are positioned adjacent to each block  38 . The blocks  38  are mounted to the appropriate cords ( 62 ,  64 ,  46 ,  68  and  66 ) by a crimp  88  that may be positioned through a hole in a block bracket  90 . The block bracket  90  is fastened to the resistance block  38  by a pin  92  or similar fastening device. The opposite end of each cord ( 62 ,  64 ,  46 ,  68  and  66 ) is fastened to the end of the bottom rail  70  of the carriage  26  by a second crimp  94 . The cable  42  may also be mounted to the bottom rail  70  by a cable crimp  96 , thus enabling displacement of the carriage  26  from the support disk assembly  32  by tension applied to the cable  42 . Any resistance blocks  38  which are secured to the adjacent disk of the support disk assembly  32  will maintain the upper position of the associated cords ( 62 ,  64 ,  46 ,  68  and  66 ) relative to the frame  22  while the lower end of that cord will move away from the support disk assembly  32 , stretching those cords and providing resistance to movement of the carriage  26 . It is understood that the invention may be positioned in any number of orientations relative to the user. This is only one version where the blocks  38  move in a vertical plane and are initially positioned near the upper portion of the frame  22 . Varying the combination of cords ( 62 ,  64 ,  46 ,  68  and  66 ) as per their selective engagement with their respective disks ( 36 ,  52 ,  48 ,  56  and  54 ) will vary the force in the cable  42  similar to that noted in Table 1, only as shown here with twice the number of variations or thirty-two settings for five cords rather than sixteen settings for four cords as previously noted. 
     The support disk assembly  32  of this embodiment is shown in  FIG. 9 . In this embodiment each disk has at least one disk lip  34 . The first disk  36  has sixteen disk lips  34 , the second disk  52  has eight disk lips  34 , the third disk  54  has four lips and the fourth disk  56  has two lips  34 . The fifth disk  48  is shown to have one disk lip  34  that covers substantially half of the perimeter of the disk  48 . Each of the disks is coupled to the shaft  50  for rotation therewith. This may be a molded part or a series of metal parts that are welded or assembled of this or other materials to create this assembly  32 . The shaft gear  58  is also securely mounted to the shaft  50  by any method known in the art. 
     A variation to the invention as presented in  FIG. 9  is to provide a series of disks that are similar in the size and general construction of the disk lip  34  but with the initial gap  98  positioned out of phase and in a set order. By doing this, resistance cords can be sequentially added with a set rotational displacement of the support disk assembly  32 . In this variation and all forms of the invention, the resistance cords ( 62 ,  64 ,  46 ,  68  and  66 ) may be one tension or provided in different tensions. Also the disk portions may be half disks, quarter disks or any other portion of a full disk. Or, instead of disks, a wheel structure may be used with a hub and spokes supporting a rim. And, the rim could be annular or segmented with a rim portion at the end of each spoke. 
     A resistance block  38  is shown in  FIG. 10  with more detail in  FIG. 11 . In this embodiment, the block  38  may include a block rail  78  which is a protrusion or other structural feature that allows guided communication with the slots  74  in the resistance block cover  72  ( FIG. 3 ). This optional structure  78  may have many numbers of variations in size, structure and orientation to the block  38 . The block lip  40  on the upper portion of the block  38  is adapted to receive the disk lip  34  to offer support to the resistance block  38  or to allow the resistance block  38  to pass through the gaps  98  between the disk lips  34 . In this embodiment the disk lips  34  include a disk flange  100  that is positioned adjacent to the wall  102  of the resistance block  38 . A block flange  104  may be used to provide stable support of the resistance block  38  under load when supported on a disk of the support disk assembly  32 . It is understood that many variations to the disk lips  34  and block lips  40  can be made. Inserts and detents can be added to the disk assembly  32  to provide more secure indexing of the components and reduce the likelihood of inadvertent movement relative to one another when one or more of the cords ( 62 ,  64 ,  46 ,  68  and  66 ) are stretched and therefore the system is under load. 
     A typical application of the display  106  is shown in  FIG. 12 . The knob  82  is positioned central to an indication display  108 . The indication display  108  includes a plurality of indexing graphics such as tick marks  110  and some if not all of the load increments noted in text  112 . Movement of the knob  82  to any position will be noted by a tick mark  110 . That actuation rotates the shaft  50  of the support disk assembly  32  altering the engagement of the disks ( 36 ,  52 ,  48 ,  56  and  54 ) with the resistance blocks  38  and associated cords ( 62 ,  64 ,  46 ,  68  and  66 ), thus altering the tension in the cable  42  as to be overcome by the user. 
     As previously noted, in an alternative embodiment the knob  82  may be mounted directly to the shaft  50  of the support disk assembly  32  on one or both ends of the shaft  50 . This eliminates the need for the gears ( 58  and  60 ) and in some situations could be desirable while maintaining the function as described herein. 
     Indexing of the knob  82 , and therefore the support disk assembly  32  to be properly positioned can be accomplished in a number of methods. A spring loaded washer with an indent for every position (in this embodiment thirty-two positions) can be positioned under the knob  82  or at any place on the support disk assembly  32 . In this embodiment the gears ( 58  and  60 ) have 32 teeth so a flexible element offering interference, such as a leaf spring, can be positioned to allow movement of the assembly  32 , but guide it to settle at any one of the  32  settings, as opposed to settling between two settings (tick marks  110 ). It is understood that the detail of the load increments, methods of indexing and graphic design can change without altering the spirit of the invention. 
     With reference to  FIGS. 13 and 14 , the device  20 ′ is shown employing an alternate resistance system. In this embodiment the resistance cords  44  have been replaced with the weight blocks  114 . The carriage  26 ′ has been slightly modified to include a series of pulleys  116  mounted at the lower end. A weight cable  118  connects the individual weight blocks  114  to the carriage  26 ′ by way of the respective pulley  116 . A recoil spring  120  connects the bottom of the carriage  26 ′ to the top of the frame  22  at the spring bracket  122 . This spring  120  provides lift to the carriage  26 ′ to bias it toward the elevated position shown so that the top of the modified resistance blocks  38 ′ are properly located so as to enable selective engagement with the support disk assembly  32  as previously described. In this position shown, the system is at rest, with no tension in the cable  42 . 
     In  FIGS. 15 and 16  the device  20 ′ of the previous figures is shown in one example of an activated state, where tension has been applied to the cable  42  to cause the carriage  26 ′ to be displaced down toward the bottom of the frame  22 . This action increases the distance between the pulleys  116  at the bottom of the engaged modified resistance blocks  38 ″ and the bottom frame member  124  of the carriage  26 ′ for only those engaged resistance blocks  38 ″ that are attached to their respective disks of the disk assembly  32 . The unengaged modified resistance blocks  38 ′ are not attached to their respective disks of the disk assembly  32  and follow with the carriage  26 ′ as it moves away from the disk assembly  32 , as they may be supported by the bottom frame member  124 . This bottom frame member  124  is analogous in function to the carriage recoil bar  76  ( FIG. 5 ) in that it supports the unengaged resistance blocks  38 ′. When the carriage  26 ′ is drawn down by the tension applied to the cable  42 , any pulley  116  that remains elevated displaces the respective weight block  114  up by way of the respective tight weight cable  118 . The slacked weight cables  118 ′ attached to weight blocks  114  that are not elevated, go slack in this process. Orientation of the disk assembly  32  selects which resistance blocks  38 ′ remain elevated and which move with the carriage, thereby altering the combination of which of the weight blocks  114  are elevated and which are not elevated when the carriage  26 ′ is moved. The combination of the mass of the weight blocks  114  lifted at any time determines the tension in the cable  42 . 
     In these views, the weight blocks  114  are shown to be different sizes. This allows for a different amount of resistance settings. For example, if the weight block number one  126  with the greatest mass is twice that of weight block number two  128 , which has twice the mass of weight block number three  130  and this continues for weight block number four  132  being twice the mass of weight block number five  134 , the sequence of resistance combinations noted with the cords can also be achieved with this combination of weight blocks  114 . This is not mandatory for the function of the device  20 ′, but in some cases it may be desirable to provide the greatest number of resistance combinations in equal increasing increments with the least number of weight blocks. 
     Another embodiment of the invention is shown in  FIGS. 17-19 . Here the device  20 ″ is shown with a cord resistance as compared to the weight blocks, but both forms of resistance could be used in this embodiment. The variation is in the modified disk assembly  32 ′. A detail of the modified disk assembly  32 ′ is shown in  FIG. 18  and a detail of the interaction of the pin-in-disk system disk  136  is illustrated in  FIG. 19 . Referring to the drawings, the disk assembly  32 ′ has been altered to include a substantially flat plate  138  with one or more pins  140  protruding from one or both sides of the plate  138 . In this embodiment the pins  140  extend from both sides of the plate  138 , as this is considered more desirable for load bearing characteristics as opposed to a cantilevered load on only one side. In some situations for clearance or assembly considerations, it may be desirable to have the pins  140  extend from only one side of the plate  138 . That will be considered an understood variation of the disclosed invention. 
     The pin  140  is similar to the disk lip  34  of the previous embodiment of the invention  20 . In this case the pin  140  provides the supportive surface necessary to engage with a recess in the block lip  40 ′. The curved surface of the pin  140  may provide a built in “self centering” or indexing feature that also helps prevent unintentional removal of the pin  140  from the block lip  40 ′. More detail of this engagement is shown in the following figures. 
     With reference to  FIGS. 20-23 , the pin-in-disk system disk assembly  32 ′ and the resistance block  38 ′″ are shown in detail. The disk assembly  32 ′ includes one or more plates  138  which are each mounted to the shaft  50 . Each plate  138  includes one or more pins  140  that extend from a surface of the plate  138 . As a common and economical form of manufacturing, the plates  138  can be constructed of steel, aluminum, plastics or like material with holes for the shaft  50  and the pins  140 . The shaft  50 , pins  140  or any combination can be press fit or positioned and welded or otherwise fastened into the proper configuration, or they may be molded or casted as one part. As previously noted, a shaft gear  58  can also be positioned on the shaft  50  to enable rotational actuation of the disk assembly  32 ′. In all embodiments, the shaft gear  58  is used only if the orientation of the shaft  50  is desired to be different from the orientation of the axis of the knob  82 . A knob  82  can also be placed on one or both ends of the shaft  50  and this gear  58  would then be eliminated. 
     The resistance block  38 ′″ is similar in construction to the previously noted embodiments of the invention with, in this embodiment, a modification to the upper section including the block lip  40 ′. In this embodiment, the block lip  40 ′ includes a center recess  142  adapted to accept the edge of the disk  138  and adjacent pin  140  to pass there through. If a pin  140  is positioned within the center recess  142  and the block  38 ′″ is displaced, the pin  140  will be received by the upper structure of the block lip  40 ′ and secured to the disk assembly  32 ′ by the pin  140 . 
     The shape of the contact area  144  of the block lip  40 ′ is shown to be concave. This is to provide a self centering feature of the pin  140  when engaged with the block lip  40 ′. The dimensions of many aspects of the block lip  40 ′ are subject to design variation. The displacement of the center of the contact area  144  relative to the adjacent outside edges of the block lip  40 ′ provides an obstruction to disassociation of the pin  140 , and therefore the disk assembly  32 ′, relative to the block  38 ′″ when a load is applied to the block  38 ′″. This feature helps “lock” the position of the disk assembly  32 ′ when it is in a loaded (cords tensioned, weight blocks lifted, or any other tension system engaged) condition thereby helps to reduce the likelihood of a weight block  38 ′″ (for example) from falling when loaded. This system can be incorporated in some form in all embodiments of the invention. 
     Another variation of the invention is shown in  FIG. 24 . In this form, the carriage  26 ″ is shown slightly displaced as is the case when the cable  42  is slightly tensioned. As noted earlier, the orientation of the carriage  26 ″ in all embodiments of the invention can be varied. When resistance cords ( 62 ,  64 ,  46 ,  68  and  66 ), as shown here, are used as a resistance source, or any other non-gravity based resistance source, the orientation relative to gravity makes no difference and though the carriage  26 ″ is shown to actuate in a vertical plane, it is understood that this is not necessary to the function of the invention and is shown here as one example of that embodiment. 
     Given the foregoing, in this embodiment, the carriage  26 ″ is guided by four carriage rollers  28  that articulate with a rounded edge of the vertical members  146  of the frame  22 ′. The round edges of the vertical members  146  are similar to the rails  24  of  FIG. 1  in that they provide a guided support surface for the carriage  26 ″ by way of the carriage rollers  28 . In this embodiment relative to the previous is, in this view, the disk assembly  32  is rotatably mounted to the carriage  26 ″. As the cable  42  is actuated by the handle  148  and pulled over the pulley  150 , the carriage  26 ″, with the disk assembly  32 , moves vertically. The cords ( 62 ,  64 ,  46 ,  68  and  66 ) have one end secured to the slide blocks  38 , as previously disclosed, and the other end is secured to the bottom frame member  152  by the crimps  94 . A break out of the bottom frame member  152  shows the crimp  94  on the highest resistance cord  46 . The rest of the cords ( 62 ,  64 ,  68  and  66 ) would have a similar fastening system to keep one end stationary with respect to the frame  22 ′ 
     As noted, the carriage  26 ″ is slightly actuated and therefore the cords ( 62 ,  64 ,  46 ,  68  and  66 ) are slightly tensioned as would be the case if all five slide blocks  38  are supported by the associated disks of the disk assembly  32  and the cable  42  is tensioned by pulling on the handle  148 . The cable  42  is secured to the carriage  26 ″ at the cross bar  154 . When the tension in the cable  42  is relaxed and the carriage  26 ″ is lowered, the slide blocks  38  are supported on the recoil bar  76 ′. In this embodiment the recoil bar  76 ′ is mounted to the frame  22 ′, but still offers support for the slide blocks  38  when the system is at rest (no tension in the cable  42 ) and also for any slide block  38  and associated cord ( 62 ,  64 ,  46 ,  68  and  66 ) that is not engaged with the associated disk of the disk assembly  32  when the carriage  26 ″ is actuated. As before, the recoil bar  76 ′ provides sustained positioning of the slide blocks  38  that are not engaged during movement of the carriage  26 ″ and in doing so allows for selective engagement when the carriage  26 ″ is returned to its resting position. 
     In all embodiments of the invention as shown and described herein, a rotary mounted engagement mechanism (disk assembly  32 ) is used to selectively engage one or more blocks  38  and their respective forms of resistance, including a cord  44  ( FIGS. 1-8 ) or other elastic element or a weight block  114  ( FIGS. 13-16 ). The engagement mechanism (disk assembly  32 ) is rotatably mounted to the frame ( FIGS. 1-8  and  13 - 17 ) or rotatably mounted to the carriage ( FIG. 24 ). In either case the disk assembly  32  enables the blocks  38  to be “directly” engaged or disengaged in a non-sequential order. For the purposes of this disclosure the term “sequential” is defined as “in order from a first end to a second end”. Therefore “direct” or “non-sequential” engagement of the block  38  mounted to the (middle positioned) heaviest cord  46  with the fifth disk  48  in  FIG. 8  is done “directly” without the necessity of any portion of the disk assembly  32  passing through any of the adjacent blocks  38 . This direct engagement is therefore “non-sequential” in that no portion of the disk assembly  32  must first pass through or engage the adjacent blocks  38  before the block  38  associated with the desired cord  46  is reached. The direct engagement is accomplished by the existence of a disk ( 48  for example) that is unique to each block  38 . This direct engagement reduces the probability of inadvertent engagement of a portion of the engagement mechanism with a block  38  not desired to be engaged when using a sequential engagement mechanism. The disk assembly  32  may be actuated as one structure, thereby providing all the combinations of resistances noted herein by the movement of one element. This provides efficiency and ease of use. 
     The foregoing detailed description of the present invention is provided for purposes of illustration and it is not intended to be exhaustive or to limit the invention to the particular embodiments shown. The embodiments may provide different capabilities and benefits, depending on the configuration used to implement key features of the invention.