Patent Publication Number: US-6669606-B2

Title: Weight selection methods and apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 09/300,546, filed on Apr. 27, 1999, which discloses subject matter entitled to the filing dates of U.S. Provisional Application Nos. 60/108,768 and 60/119,014, filed on Nov. 17, 1998, and Feb. 8, 1999, respectively, and this application also discloses subject matter entitled to the filing date of U.S. Provisional Application No. 60/171,813, filed on Dec. 21, 1999. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to exercise equipment and more particularly, to weight selection methods and apparatus. 
     BACKGROUND OF THE INVENTION 
     Various weight selection methods and apparatus have been developed to provide adjustable resistance to exercise. In the case of free weights, for example, weight plates are typically mounted on opposite ends of a bar. In relatively advanced systems, the bar is stored in proximity to the weight plates, and a selection mechanism is provided to connect a desired amount of weight to the bar. Some examples of patented barbell/dumbbell improvements and/or features are disclosed in U.S. Pat. No. 4,284,463 to Shields (discloses a dumbbell assembly having opposite side weights which are maintained in alignment on a base and selectively connected to a handle by means of cam driven pins on the weights); U.S. Pat. No. 4,529,198 to Hettick, Jr. (discloses a barbell assembly having opposite side weights which are maintained in alignment on respective storage members and selectively connected to a handle by means of axially movable springs); U.S. Pat. No. 4,822,034 to Shields (discloses both barbell and dumbbell assemblies having opposite side weights which are maintained in alignment on a shelf and selectively connected to a handle by means of latches on the weights); U.S. Pat. No. 5,769,762 to Towley, III et al. (discloses a dumbbell assembly having a plurality of interconnected opposite side weights which are stored in nested relationship to one another and selectively connected to a handle by various means); and U.S. Pat. No. 5,839,997 to Roth et al. (discloses a dumbbell assembly having opposite side weights which are maintained in alignment on a base and selectively connected to a handle by means of eccentric cams on a rotating selector rod. Despite these advances and others in the field of weight selection, room for improvement remains. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention is to provide weight selecting members that are rotatable into engagement with respective weight plates to provide adjustable resistance to exercise movement. In a preferred application, the weight selecting members are mounted on a rod that extends horizontally and is movable radially into and out of a horizontal array of weights. On one embodiment, the weight selecting members are rigidly secured to the rod and rotate together therewith. On another embodiment, the weight selecting members are rotatably mounted on the rod and rotate relative thereto. Additional features and/or advantages of the present invention will become apparent to those skilled in the art from the more detailed description that follows. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING 
     With reference to the Figures of the Drawing, wherein like numerals represent like parts and assemblies throughout the several views, 
     FIG. 1 is a side view of an exercise dumbbell constructed according to the principles of the present invention; 
     FIG. 2 is partially sectioned side view of one end of the dumbbell of FIG. 1; 
     FIG. 3 is an end view of a knob on the dumbbell of FIG. 1; 
     FIG. 4 is an opposite side view of the knob of FIG. 3; 
     FIG. 5 is a side view of one end of a shaft on the dumbbell of FIG. 1; 
     FIG. 6 is an end view of the shaft of FIG. 5; 
     FIG. 7 is a side view of a first weight engaging member on the dumbbell of FIG. 1; 
     FIG. 8 is an end view of the weight engaging member of FIG. 7; 
     FIG. 9 is a side view of a second weight engaging member on the dumbbell of FIG. 1; 
     FIG. 10 is an end view of the weight engaging member of FIG. 9; 
     FIG. 11 is a side view of a third weight engaging member on the dumbbell of FIG. 1; 
     FIG. 12 is an end view of the weight engaging member of FIG. 11; 
     FIG. 13 is a top view of three adjacent weights on the dumbbell of FIG. 1; 
     FIG. 14 is an end view of one of the weights shown in FIG. 13; 
     FIG. 15 is a side view of the weight of FIG. 14; 
     FIG. 16 is an opposite end view of the weight of FIG. 14; 
     FIG. 17 is a partially sectioned top view of the weights of FIG. 13 resting on a cradle constructed according to the principles of the present invention; 
     FIG. 18 is a partially sectioned side view of the weights and cradle of FIG. 17; 
     FIG. 19 is an end view of the cradle of FIG. 17 without the weights; 
     FIG. 20 is a top view of another dumbbell constructed according to the principles of the present invention; 
     FIG. 21 is a side view of the dumbbell of FIG. 20; 
     FIG. 22 is a side view of a weight selector on the dumbbell of FIGS. 20-21; 
     FIG. 23 is an end view of the weight selector of FIG. 22; 
     FIG. 24 is a side view of the weight selector of FIG. 22 rotated to a weight engaging orientation; 
     FIG. 25 is an end view of the weight selector of FIG. 24; 
     FIG. 26 is a top view of weights plates suitable for use with the dumbbell of FIGS. 20-21; 
     FIG. 27 is an end view of one of the weight plates of FIG. 26; 
     FIG. 28 is a side view of the weight plate of FIG. 27; 
     FIG. 29 is an opposite end view of the weight plate of FIG. 27; 
     FIG. 30 is a top view of a dumbbell similar to the dumbbell of FIGS. 20-21, with optional features added; 
     FIG. 31 is a top view of a dumbbell similar to the dumbbell of FIGS. 20-21, with respective opposite side weight selectors connected to one another; and 
     FIG. 32 is a side view of the dumbbell of FIG.  31   
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention provides methods and apparatus for selectively adjusting weight resistance to exercise motion. Generally speaking, one or more weight selecting members are rotated into and out of engagement with weight plates in order to select a desired number and/or combination of the weight plates. 
     A first embodiment of the present invention is an exercise dumbbell designated as  500  in FIG.  1 . The dumbbell  500  has an intermediate handle  510  that is sized and configured for grasping, and opposite end, weight housings  520  that are sized and configured to accommodate respective weight plates  530 ,  540 , and  550 . When not in use, the supports  520  and the weight plates  530 ,  540 , and  550  rest on a base or cradle designated as  600  in FIGS. 17-19. Other suitable weight supporting arrangements are disclosed in U.S. Pat. No. 4,284,463 to Shields; U.S. Pat. No. 4,529,198 to Hettick, Jr.; U.S. Pat. No. 4,822,034 to Shields; U.S. Pat. No. 5,769,762 to Towley, III et al.; U.S. Pat. No. 5,839,997 to Roth et al.; U.S. Pat. No. 6,033,350 to Krull; and/or U.S. Pat. No. 6,099,442 to Krull, all of which are incorporated herein by reference. 
     The handle  510  is a cylindrical tube having a longitudinal axis and opposite ends secured to respective housings  520  by welding or other suitable means. Each of the housings  520  includes an inside end wall  522 , an outside end wall  526 , a top wall  528 , and opposite side walls  529 , which cooperate to define a downwardly opening compartment. FIG. 1 shows integrally molded housings  520 , and FIG. 2 shows an alternative housing  520 ′ that is identical in size and configuration, but assembled from three discrete parts. In either case, spacers may extend downward from the top wall  528  to occupy axial spaces between the weight plates  530 ,  540 , and  550 . Axially offset shoulders  524  are provided on interior, diametrically opposed sides of each end wall  522  and  526  to engage respective weights  530  and  550  and provide centrally located gaps therebetween. The shoulders  524  are disposed inward from the outside edges of the walls  522  and  526 . 
     A selector rod  560  is rotatably mounted relative to both the handle  510  and the housings  520 . The selector rod  560  includes a shaft  561  and two sets of three weight engaging members or supports  570 ,  580 , and  590  mounted on opposite ends of the shaft  561 . The shaft  561  includes an intermediate portion  562  having a circular profile, and opposite end portions  563  having clipped circular profiles (a flat surface is cut into an otherwise circular profile). The intermediate portion  562  extends through the handle  510  and through the inside end wall  522  of each housing  520 . Each end portion  563  extends through a respective housing  520  and through a respective outside end wall  526 . 
     The innermost weight support  570  is shown by itself in FIGS. 7-8. The support  570  includes an axially extending hub  578 , a radially extending rim  576 , and an axially extending lip  573 . The support  570  is a single piece of integrally molded plastic, and the rim  576  may be said to be integrally connected between the lip  573  and the hub  578 . An opening  579 , sized and configured to receive an end  563  of the shaft  561 , extends through the hub  578  and the rim  576 . The lip  573  includes a single, continuous segment which extends through an arc of 167.5° The single segment spans several sectors, including sector Z, but it does not span any portion of sector A. 
     The intermediate weight support  580  is shown by itself in FIGS. 9-10. The support  580  includes an axially extending hub  588 , a radially extending rim  586 , and an axially extending lip  584 . The support  580  is a single piece of integrally molded plastic, and the rim  586  may be said to be integrally connected between the lip  583  and the hub  588 . An opening  589 , sized and configured to receive an end  563  of the shaft  561 , extends through the hub  588  and the rim  586 . The lip  583  includes two diametrically opposed segments which extend through respective arcs of 77.5° One of the segments spans the sector Z, as well as another adjacent sector, but neither of the segments spans any portion of the sector A. 
     The outermost weight support  590  is shown by itself in FIGS. 11-12. The support  590  includes an axially extending hub  598 , a radially extending rim  596 , and an axially extending lip  594 . The support  590  is a single piece of integrally molded plastic, and the rim  596  may be said to be integrally connected between the lip  593  and the hub  598 . An opening  599 , sized and configured to receive an end  563  of the shaft  561 , extends through the hub  598  and the rim  596 . The lip  593  includes four circumferentially spaced segments which extend through respective arcs of 32.5° One of the segments spans the sector Z, but none of the segments spans any portion of the sector A. 
     A fastener is fastened to one end  563  of the shaft  561 , just beyond the outside end wall  526 , and a knob  565  is fastened to an opposite end  563  of the shaft  561  just beyond the opposite, outside end wall  526 . As shown in FIGS. 3-4, the knob  565  includes a relatively large diameter rim  566  which is sized and configured for grasping, an intermediate portion  567  which bears against the outside end wall  526 , and a relatively small diameter hub  568  which extends through the outside end wall  526 . A recess  506  is provided in the hub  568  to receive a discrete fastener in countersunk fashion. Both the knob  565  and the supports  570 ,  580 , and  590  rotate together with the shaft  560  relative to the housings  520  and the handle  510 . 
     The weight plates  530 ,  540 , and  550  are shown in greater detail in FIGS. 13-16. The two plates  540  and  550  are shown with the same thickness, but the plate  550  is one-half as dense and thus, weighs one-half as much as the plate  540 , which in turn, weighs one-half as much as the plate  530 . The front and back views of the plate  550  shown in FIGS. 14 and 16 are representative of similar views of the other plates  540  and  530 . 
     Each side of the plate  550  (and the plates  540  and  530 ) may be described with reference to a relatively thinner, intermediate portion  551  and relatively thicker, opposite side portions  552 . The side portions  552  bear against adjacent counterparts and/or against shoulders  524  on respective end walls  522  or  526 , and the intermediate portion  551  cooperates with adjacent counterparts and/or the end walls  522  or  526  to define gaps  545  disposed between the side portions  552  and the shoulders  524 . The gaps  545  are sized and configured to receive respective weight supports  570 ,  580 , and  590 . FIG. 14 shows how the plates  550 ,  540 , and  530  axially align with the supports  590 ,  580 , and  570  (the rim sectors A-Z are shown in dashed lines). 
     An elongate slot  556 , sized and configured to accommodate the axial hub  598 ,  588 , or  578  of a respective support  590 ,  580 , or  570  extends downward into each of the plates  550 ,  540 , and  530 . Immediately beneath the slot  556 , a peg  559  projects axially outward from the intermediate portion  551  of the plate  550  (and each of the plates  540  and  530 ). The peg  559  is disposed just inside the space (sectors A-Z) occupied by the axially extending lip  595  on the support  590 . When a segment of the lip  595  is disposed beneath the peg  559 , the plate  550  is constrained to move upward together with the handle  510 . 
     The upper ends of the side portions  552  terminate in respective laterally extending portions  553  that extend away from one another. The lateral portions  553  are the same thickness as the side portions  552 . The lower ends  554  of the side portions  552  are beveled or tapered. Relatively thinner, triangular fins  555  extend between respective lateral portions  553  and respective side portions  552 . The fins  555  are sized and configured to fit within opposing slots  625  in the base  600 , and the lateral portions  553  are designed to rest on top of the ledge  603 . Similar fins  555  on the plates  540  and  530  are sized and configured to fit within other, respective slots  624  and  623  in the base  600 . The grooves  623 - 625  are bounded by inclined, opposing walls which cooperate to center the plates  530 ,  540 , and  550  relative to the base  600 . Additional grooves  622  and  626  are provided in the base  600  to receive the end walls  522  and  526 , respectively. The grooves  626  are bounded by relatively outward walls which are inclined upward and away from the middle of the base  600 . Those skilled in the art will recognize that alignment of the weight plates may be achieved in various ways without departing from the scope of the present invention. 
     The base  600  includes a bottom  610  sized and configured to rest upon a flat surface, such as a table top or floor. Opposite end portions  601  and  602  extend upward from the bottom  610 . In addition to outside walls, interior walls  604  extend upward from the bottom  610  and between opposing end walls  522  on respective housings  520 . Elongate slots  606  extend downward into the interior walls  604  to accommodate the handle  510 . When the plates  530 ,  540 , and  550  are suspended from the base  600 , the slots  606  align with the slots  556 . 
     The supports  570 ,  580 , and  590  are designed for rotation in 45° increments. A ball detent or other known biasing system may be interconnected between the housing  520  and either the knob  565  or the shaft selector rod  560 , for example, to bias the selector rod  560  toward the desired orientations. The lips  573 ,  584 , and  595  are configured to provide clearance or tolerance vis-a-vis the pegs  559 . In particular, when any given plate  530 ,  540 , or  550  is not engaged, the respective lip  573 ,  584 , or  595  is at least 6.5° outside the boundary of the peg  559 . With reference to the support  590 , for example, each of the lip segments  595  spans an arc of 32.5°. 
     The weight selecting members  570 ,  580 , and  590  may also be configured to minimize wobbling or rattling of the selected weight plates. For example, leaf springs may be incorporated into the members  570 ,  580 , and  590  during the molding process, for purposes of exerting pressure against any selected weights. Moreover, the weights may also be configured to be relatively thicker just beneath the peg  559 , so that the leaf springs are relatively more compressed when disposed beneath the peg  559 . 
     The configurations of the plates  530 ,  540 , and  550  and the weight supports  570 ,  580 , and  590  are such that any combination of the plates  530 ,  540 , and  550  may be secured to the handle  510  form removal from the base  600 . In this regard, when the supports  570 ,  580 , and  590  occupy the respective orientations shown in FIGS. 8,  10 , and  12 , the plate  530  is engaged to the exclusion of the plates  540  and  550 . When the supports  570 ,  580 , and  590  are rotated 180°, the sector designated as A underlies the pegs  559  on the plates  530 ,  540 , and  550 , and none is secured to the handle  510 . When the supports  570 ,  580 , and  590  are rotated until the sector designated as Z underlies the pegs  559 , all of the plates  530 ,  540 , and  550  are engaged. 
     Assuming that the handle  510  and the housings  520  collectively weigh ten pounds, and the plates  530 ,  540 , and  550  weigh ten pounds, five pounds, and two and one-half pounds, respectively, the following chart shows how different amounts of weight may be selected as a function of the orientation of the selector rod  560 . 
     
       
         
           
               
               
               
               
               
               
             
               
                   
               
               
                 Rod 
                 Handle 
                 Weights 590 
                 Weights 580 
                 Weights 570 
                 Total 
               
               
                   
               
             
            
               
                 — 
                 10 
                 0 
                 0 
                 0 
                 10 
               
               
                  45° 
                 10 
                 5 
                 0 
                 0 
                  5 
               
               
                  90° 
                 10 
                 0 
                 10  
                 0 
                 20 
               
               
                 135° 
                 10 
                 5 
                 10  
                 0 
                 25 
               
               
                 180° 
                 10 
                 0 
                 0 
                 20  
                 30 
               
               
                 225° 
                 10 
                 5 
                 0 
                 10  
                 35 
               
               
                 270° 
                 10 
                 0 
                 10  
                 20  
                 40 
               
               
                  35° 
                 10 
                 5 
                 10  
                 20  
                 45 
               
               
                 360° 
                 10 
                 0 
                 0 
                 0 
                 10 
               
               
                   
               
            
           
         
       
     
     An advantage of this embodiment  500  is that only three discrete weights are required on each side of the dumbbell to provide eight different, balanced dumbbell loads. Moreover, the number of available dumbbell loads may be doubled by adding two “half-weights” which weigh one-half as much as one of the plates  590 . For example, half-weights could be connected to the inside end walls  522  of the base  510  by means of hook and loop fasteners. 
     Another advantage of the dumbbell  500  is that it can be manufactured relatively efficiently, especially as compared to the dumbbell disclosed in U.S. Pat. No. 5,839,997 to Roth et al. For example, the relatively gross, “over/under” relationship between the weight supports  570 ,  580 , and  590  and the weight plates  530 ,  540 , and  550  requires a less stringent manufacturing process. The weight supports  570 ,  580 , and  590  are relatively simple parts which may be injection molded, and the weights  530 ,  540 , and  550  are relatively simple parts which may be cast. 
     FIGS. 20-29 show another dumbbell constructed according to the principles of the present invention. The dumbbell  1500  has weight selectors  1570 ,  1580 , and  1590  which rotate relative to a handle  1520  and independent of one another to provide eight different, balanced weight combinations (and sixteen combinations if balance is not a critical concern). 
     First and second weight supporting boxes  1512  are rigidly secured to respective end portions of the handle  1520  to collectively define a base  1510 . The weight selectors  1570 ,  1580 , and  1590  are disposed inside the boxes  1512  and are rotatably mounted on respective end portions of the handle  1520 . To the extent that economies of scale may warrant making all of the weight selectors identical, spacers  1525  are also mounted on the handle  1520  to accommodate the additional thickness of the largest weight plates  1550 . The boxes  1512  define weight receiving compartments  1514 , and the weight selectors  1570 ,  1580 , and  1590  divide the compartments  1514  into individual weight receiving slots. 
     FIGS. 22-23 show the weight selector  1590  in a disengaged orientation, and FIGS. 24-25 show the weight selector  1590  in a weight engaging orientation. The weight selector  1590  includes a cylindrical hub  1598  with a circular hole  1599  extending through same. A circular plate  1596  extends radially away from the hub  1598 , and a cylindrical rim  1595  extends circumferentially about the majority of the plate  1596 . The gap in the rim  1595  is disposed vertically beneath the hub  1598  when the weight selector  1590  occupies the disengaged orientation shown in FIGS. 22-23. An arm  1591  extends radially away from the rim  1595  and terminates in an axially extending handle  1592 . 
     FIGS. 26-29 show weight plates  1530 ,  1540 , and  1550  suitable for use with the dumbbell  1500 . Each plate  1530  weighs ten pounds; each plate  1540  weighs five pounds; and each plate  1550  weighs two and one-half pounds. The plates may be described as generally square plates having chamfered lower corners and relatively thick side walls  1552 . The walls  1552  on adjacent plates cooperate to define central gaps ( 1548 , for example) between the plates to accommodate respective, intervening weight selectors. An elongate slot  1556  extends downward from an upper edge of each plate to accommodate the hub  1598  of a respective weight selector. A boss  1559  projects outward from the plate immediately beneath the lower end of the slot  1556  for selectively engagement by the rim  1595  on a respective weight selector (see dashed lines). As suggested by other embodiments discussed above, the weight plates are stored on a suitable cradle when not in use. 
     The arm  1591  on each of the weight selectors  1570 ,  1580 , and  1590  extends through a respective slot ( 1517 , for example) in the base  1510 , thereby making each handle  1592  accessible to a user. The ends ( 1507 , for example) of the slots are notched to discourage undesired rotation of the handles  1592 . In particular, the handles  1592  must be forced toward the center of the dumbbell  1500  prior to pivoting relative to the handle  1520 . The resilient nature of the arms  1591  accommodate this level of deflection, in a manner similar to a leaf spring. 
     As suggested by the common reference numerals, FIG. 30 shows a dumbbell  1500 ′ similar to the dumbbell  1500 , but with three additional features. First, indicia  1527 ,  1528 , and  1529  on the tops of the boxes  1512 ′ show the appropriate positions for the handles of respective weight selectors  1570 ,  1580 , and  1590  for any desired amount of weight to be selected. For example, if twenty-five pounds is desired, then the handle  1592  on the weight selector  1590  is rotated toward the right side of FIG. 30, and the handles  1592  on the weight selectors  1580  and  1590  are rotated toward the left side of FIG.  30 . Second, indicia  1521 ,  1522 , and  1523  are provided on the handle  1520 ′ to show appropriate center positions for the amount of weight that is selected. For example, if equal weight is selected on each end of the handle  1520 ′, then a person should center his hand relative to the line  1521 . On the other hand, if twenty-seven and one-half pounds is selected by rotating only the handle  1592  on the lower weight selector  1590  toward the right side of FIG. 30, then a person should center his hand relative to the line  1523 . One or both forms of similar indicia may be provided on other embodiments discussed herein, as appropriate. 
     The tops of the boxes  1512 ′ on the dumbbell  1500 ′ are provided with relatively larger openings  1502  at the ends of the slots nearer the right side of FIG.  30 . The openings  1502  are sized and configured to admit passage of the handles  1592  during assembly of the dumbbell  1500 ′. Similar openings  1502  may be provided on the dumbbell  1500 , or the weight selectors  1570 ,  1580 , and  1590  may be assembled from more than one piece to facilitate insertion of the arms  1591  through the slots, or the handles  1592  may be made no larger than the openings  1507  shown in FIG.  20 . 
     FIGS. 31-32 show a dumbbell  1600  similar to the dumbbell  1500 , but with interconnected pairs of weight selectors designated as  1670 ,  1680 , and  1690 , and a base  1610  that has been modified to accommodate same. The base  1610  includes the same handle  1520  and similarly sized boxes  1612  rigidly secured to opposite ends of the handle  1520 . As on the two previous embodiments, the boxes  1612  define weight receiving compartments  1514  which are separated into individual weight slots by weight selectors rotatably mounted on the handle  1520 . The top of each box  1612  is provided with an upwardly extending rim  1613  that extends along the outside end and the opposing sides to shelter the weight selectors and structure for latching same in place. 
     The weight selector  1670  may be described in terms of opposite side weight selectors  1570  having their handles  1592  interconnected by an integral extension  1673 . The weight selector  1680  may be described in terms of opposite side weight selectors  1580  having relatively longer arms and their handles  1592  interconnected by a relatively longer integral extension  1683 . The weight selector  1690  may be described in terms of opposite side weight selectors  1590  having even longer arms and their handles  1592  interconnected by an even longer integral extension  1693 . Relatively longer slots ( 1619 , for example) are provided in the tops of the boxes  1612  to accommodate pivoting of the longer arms. For assembly purposes, the arms may be inserted through respective slots and then interconnected by respective extensions  1673 ,  1683 , and  1693 . Inverted L-shaped tabs  1609  are provided on the boxes  1612  proximate the ends of the slots to latch respective weight selector pairs  1670 ,  1680 , and  1690  in place. The tabs  1609  and/or the arms resiliently deflect to accommodate the latching and unlatching process. An advantage of this embodiment  1600  is that the opposite side weight plates are latched and unlatched simultaneously. 
     The present invention may also be described in various ways. For example, the present invention may be described as an adjustable exercise weight system, comprising: a base which includes a handle and weight supports at opposite ends of the handle; weights sized and configured for engagement by the weight supports; and weight selectors rotatably mounted on the handle and disposed adjacent respective weights, wherein each of the weight selectors is independently rotatable between a weight engaging orientation and a free orientation relative to a respective one of the weights. The weights may be provided in opposite side pairs, and/or the opposite side weight selectors associated with each of the pairs may be interconnected to move as a unit. In addition and/or the alternative, indicia may be provided to show how the weight selectors should be maneuvered to select a desired amount of weight, and/or to indicate where the handle should be grasped in order to offset an imbalance in the amount of selected weight at each end of the handle. 
     The present invention may also be described in terms of various methods of providing adjustable weight resistance. For example, one such method involves the provision of a plurality of aligned weights; the provision of a discrete weight support for each of the weights; and the rotation of the supports relative to the weights until a respective weight support underlies each desired weight. This method may further involve mounting the weight supports on a rod, and providing slots in the weights to receive the rod; having the rod occupy all such slots during rotation, regardless of which weights are being selected; rotating the rod a fraction of a revolution to engage an additional weight; and/or exerting pressure against the selected weights. With regard to this last option, a weight stabilizing system may be implemented by providing protruding portion(s) on the weight plates and/or the weight selectors, and arranging the protruding portions to engage only when the weight selectors are rotated into engagement with respective weights. For example, a leaf spring on the weight selector may be arranged to occupy the slot in the weight when not engaged, and to rest between spaced apart bumps on the weight when the weight selector is moved to an engagement orientation. 
     The present invention may also be described as a method of adjusting exercise resistance, involving provision of a plurality of aligned weights; provision of a discrete weight support for each of the weights; and rotation of the weight supports into engagement with desired weights. The weight supports may be independently rotated or secured to a common selector rod. In the latter case, the selector rod may be rotated a first amount relative to the weights to engage a first weight; and rotated a second amount relative to the weights to engage a second weight. Such a method may further involve rotating the selector rod a first amount to engage only the first weight, a second amount to engage only the second weight, and a third amount to engage both the first weight and the second weight. 
     The foregoing description and accompanying figures are limited to only some of the many conceivable embodiments to be constructed in accordance with the principles of the present invention. Other embodiments, methods, and/or modifications will become apparent to those skilled in the art as a result of this disclosure. Moreover, those skilled in the art will also recognize that aspects and/or features of various methods and embodiments may be mixed and matched in numerous ways to arrive at still more variations of the present invention. In view of the foregoing, the scope of the present invention is to be limited only to the extent of the following claims.