Patent Publication Number: US-7591772-B2

Title: Exercise device including collar coupling

Description:
FIELD OF THE INVENTION 
   The present subject matter relates generally to an exercise device and to a coupling system for releasably securing a weight to an end of a bar. 
   BACKGROUND OF THE INVENTION 
   Exercise devices such as barbells are used for weight training. The barbell comprises a bar having a first weight. A user may do weightlifting exercises with the bar alone for training. Alternatively, the user selects a pair of weights and releasably secures one weight to each end of the bar. A number of pairs of differently sized weights are provided so that a user may select a total weight with which to exercise. In another form of exercise device, a barbell is formed with a yoke portion. Rather than doing lifting exercises, the user places the barbell over the shoulders, with the yoke going behind the neck. The user may perform trunk twists and bends using the bar to maintain positions of the arms and torso for maximum effectiveness of the exercises. The bar is configured for adding weight inside or outside and particularly at its ends for increasing the rotational moment of inertia of the bar to give the effect of greater weight. 
   An example of a trunk exerciser is shown in U.S. Pat. No. 5,312,314. An exercise bar includes a yoke. In one form, the exercise bar comprises five sections that fit in a carrying case. In one embodiment, weights can be inserted in hollow ends of the bar. End caps are press fit over the ends of the bar. The range of weight that can be provided is necessarily limited by the space inside the ends of the bars. In another embodiment, weights are inserted over an exterior of each end and held in place by a collar including a setscrew. The end cap and the setscrew each provide for an interference fit rather than positively retaining the cap or collar in place with a stop element. In another form, weights are retained on each end of the bar by a screw with a broad head threaded into an end of the bar. The screw does not permit quick release or engagement of the retained weights. 
   U.S. Pat. No. 5,295,934 and U.S. Pat. No. 6,007,268 each disclose a locking release collar assembly received over a bar. The collar is adapted to be axially received on and to be removably fixed at a selected location axially between a weight mounted on the bar and an end of the bar. The release collar includes an assembly in which radially moveable ball detents are cammed into frictional engagement with the shaft and rest in a groove. A spring-biased collar member is moved axially to permit the ball detents to move radially outwardly out of the groove to unlock the release collar. In this construction, a weight cannot be mounted on an end of a bar. The weight must move axially inwardly of the end of the bar. The release collar is an additional component which must be provided in addition to the weight and the bar. This structure does not provide for securing a weight to an end of the bar. As a practical matter, a user must apply force to circumferentially opposed portions of the collar. These collars are not operated by a single application of force to a single location such as a button. 
   U.S. Pat. No. 4,854,576 discloses weights each integral with a collar that slides on to the end of the bar. A spring clip inside the bar radially biases each of two radially opposed detent pins outwardly through holes in the bar into recesses in the collar. To release a weight, a user must push fingertips through the holes to push the pins into the bar. There is no mechanism to operate the pins outside of the holes or to keep the pins in a radially inward position when the user&#39;s fingers are removed. Also, the collar exerts a shearing force against the pins which can also exert a moment on each pin tending to pull the pin from the spring clip. A detent mechanism immune to the generation of force moments is not provided. 
   The prior art does not disclose a system for retaining a weight on an end of a bar which is positively operable between an engaged and disengaged position and in which in a retainer assembly separate from the bar or the weight is not required. 
   The above cited art discloses bars which may be used with a pair of weights that is selected from a set of a plurality of pairs of weights. Systems utilizing a set of pairs of weights may include a rack or cabinet to support the pairs of weights. However, the weights generally rest on a rack and do not engage a support in a manner similar to that in which the weights would engage the bar. 
   SUMMARY OF THE INVENTION 
   Briefly stated, in accordance with embodiments of the present invention, an exercise device and a coupling for releasably securing a weight collar to an end of a bar are provided. The bar has an end to receive the weight collar. A coupling mechanism may be included in either the bar or the weight collar. The mechanism cooperates with a stop in the other of the bar or the weight collar. 
   An assembly to releasably secure the weight collar to the bar includes an axially extending first recess formed in either the bar or the weight collar. The recess is coaxial with the bar and communicates with a radial surface at a proximal end of the assembly. An actuator, which may comprise a generally cylindrical body, is axially movable within the first recess. A detent means located in said actuator cooperates with the actuator to selectively engage stop means to prevent relative axial motion of said bar and said collar. The stop means is in the other of said bar and said collar. A recess in the actuator has a first depth along a first axial extent and a second depth along a second axial extent of said recess. The first depth is at least equal to a radial dimension of the detent means, and said second depth is less than the radial dimension of said detent means. Camming of the actuator against the detent means causes the detent means to engage the stop means. The first axial extent of the recess is in registration with the stop means when said actuator in a first axial position and the second axial extent is in registration with said stop means when the actuator is in a second axial position. An aperture communicates the recess with an exterior of the actuator so the detent means can engage the said stop means when said actuator is in said second axial position. The actuator is selectively maintained in one of said first and second positions. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present subject matter may be further understood by reference to the following description taken in connection with the following drawings: 
       FIGS. 1 and 2  are respectively an isometric view and a plan view of a system in accordance with an embodiment of the invention comprising a bar and weights; 
       FIG. 3  is a partial detailed view of  FIG. 2 ; 
       FIG. 4  is a cross sectional view taken along a diameter of the bar; 
       FIG. 5  is an isometric view, partially broken away, illustrating an end of a bar and a weight collar to be received on a bar; 
       FIG. 6  is an exploded view of the weight collar of  FIG. 5 ; 
       FIG. 7  consists of  FIGS. 7   a - 7   c , each of which is a cross sectional elevation illustrating a different form actuator disposition in a weight collar; 
       FIG. 8  is a cross sectional elevation in which a weight receives a bar, rather than a bar receiving a weight; 
       FIG. 9  consists of  FIGS. 9   a - 9   e , each of which is a cross sectional elevation illustrating operation of an embodiment; 
       FIG. 10  is an isometric view of the weight collar engaged with the bar; 
       FIG. 11  is an isometric view illustrating a further form of an end of a bar to be received in a weight collar in which the actuator is included in the bar rather than in the weight collar; 
       FIG. 12  is a cross sectional view of the apparatus of  FIG. 11  taken along a diameter of the bar and the weight collar; 
       FIG. 13  consists of  FIGS. 13   a - 13   c , each of which is a cross sectional elevation in which structure and operation of an embodiment including a magnetic latch are illustrated; 
       FIG. 14  is a cross sectional elevation of an embodiment including an electromagnetic latch; and 
       FIGS. 15 and 16  are respectively a front and a side elevation illustrating a weight support system interacting with a set of weights. 
   

   DETAILED DESCRIPTION 
     FIGS. 1 and 2  are respectively an isometric view and a plan view of an exercise device  1  constructed in accordance with an embodiment of the present invention. The exercise device  1  comprises a bar  2  and a pair of weights  4  which comprises weight collars  7  and  8 , each releasably securable to an opposite end of the bar  2 . Straight portions of the bar  2  lie on an axis  3 . The exercise device  1  can be used, for example as a dumbbell. Alternatively, the exercise device  1  may be supported on the shoulders of a user performing trunk exercises. A plurality of pairs of weights  4  may be provided so that a user may select a total weight with which to exercise. 
   The bar  2  could be a hollow tube or a solid bar. To facilitate transportability, the bar  2  may comprise sections that are connected, such as by threads at threaded ends. In the present illustration, a central section  10  is surrounded by end sections  11  and  12 . Other numbers of sections could be provided. For a dumbbell embodiment, the central section  10  may be straight. In an embodiment for trunk exercises, the central section  10  is provided with a curve to fit around a user&#39;s neck when the bar  2  rests on the user&#39;s shoulders. The bar  10  has first and second proximal ends  16  and  18 . In the present description proximal describes a location at an end, and distal refers to a center of the bar  2 . In accordance with this convention, a description of interaction of the weight collar  7  in the exercise device  1  will also describe the interaction of the weight collar  8 . 
   The weight collars  7  and  8  are releasably secured to proximal ends  16  and  18  respectively. The weight collars  7  and  8  may each be regarded as first coupling members, and the proximal ends  16  and  18  may each be regarded as second coupling members. At each end of the bar  2 , a mechanism, further described below with respect to  FIG. 5  and other Figures, operates detent means to engage stop means, further described below with respect to  FIG. 4  and other Figures. In an embodiment in which the mechanism is in each of the first coupling members, and the stop means is in each of the second coupling members. One convenient form of a detent is a ball bearing. A stop means could comprise a circular groove. The mechanism moves the detent radially to engage the groove and secure the first coupling member to the second coupling member in a first, engaged position. The mechanism is operated to move the detent radially to be removed from the groove in a second, disengaged position and release one of the weight collars  7  or  8 . 
     FIGS. 3 and 4  are respectively a partial detailed view of  FIG. 2  and a cross sectional view taken along a diameter of the bar illustrating connection of the sections to the section  11 . The section  12  is connected to the section  10  in the same manner. The section  10  has a proximal end  20 , and the section  11  has a distal end  22 . The proximal end  20  of the section  10  has a cylindrical plug  24  received therein. The plug  24  has a threaded, axially extending central bore  26 . The distal end  22  of the section  11  contains a cylindrical plug  28  having a threaded coaxial cylindrical extension  30 . The cylindrical plugs  24  and  28  may be press fit, welded or otherwise secured to the section ends  20  and  22  respectively. Mating, radially extending faces of the cylindrical plugs  24  and  28  are preferably perpendicular to the axis  3 . To connect the section  11  to the section  10 , the coaxial extension  30  is threaded into the central bore  26 . If a “right handed” thread is used, this will be accomplished by a rotation in which the section  11  rotates counterclockwise with respect to the section  10 . To disconnect the sections  10  and  11 , rotation of the coaxial cylindrical extension  30  is counterclockwise with respect to the central bore  26 . 
     FIG. 5  is an isometric view, partially broken away, illustrating an end of a bar and a weight collar to be received on a bar.  FIG. 6  is an exploded view, respectively, illustrating components of one form of weight collar  7 . The following discussion is with respect to both  FIGS. 5 and 6 . In this embodiment, the above-mentioned mechanism, further described below, is included in the weight collar  7 , and the stop means is included in the section  11 . The proximal end  16  of the section  11  has an edge  29 . An axial bore  31  communicating with the edge  29  has a preselected depth and an inner wall  32  to receive a projection, described below, from the weight collar  7 . Distally beyond the axial bore  31  is an alignment socket  36  having a shape that will not permit rotation of a member mating in the socket. In the present illustration, the alignment socket  36  is hexagonal in a radial plane. Hexagonal sockets are commonly used in tools, but other shapes could be utilized. At a preselected distance distally from an opening of the axial bore  31 , a stop means  37  is provided to cooperate with a mechanism further described below. The stop means  37  may conveniently comprise a circumferential groove  38  formed in the inner wall  32 . The stop means  37  could comprise other structure for receiving detent means to prevent relative axial motion of the weight collar  7  with respect to the section  11 . A groove is a convenient form of stop means since no particular rotational alignment of the section  11  with respect to the weight collar  7  is required. 
   The weight collar  7  provides a user with the option of releasably securing a preselected weight to an end of the bar  2  and includes a mechanism for releasably securing the weight collar  7  to the bar  2 . The weight collar  7  comprises a weight cap  40  and a weight cylinder  42 . In the present illustration, a separate weight cap  40  and a weight cylinder  42  are provided for improved manufacturability and to accommodate a total weight of the weight collar  7  while maintaining a limited radial dimension. The greater the weight of the weight collar  7 , assuming the same material is used, the greater its volume must be. In order to maintain a limited radial dimension, the axial dimension of the weight cylinder  42  must be increased to provide for additional weight. In order to provide for a substantially constant axial length of the exercise device  1  increasing sizes of weight collars  7  extend further distally from the proximal end of the weight cap  40 . 
   Maintaining a limited radial dimension and a substantially constant axial dimension of the exercise device  1  may provide an aesthetically desired appearance. This also facilitates design of efficient containers for sets of weights, thus enhancing portability of the exercise device  1 . Since the weight cylinder  42  will surround the circumference of coupling mechanisms in the weight cap  40 , in order to facilitate assembly of the weight cap  40 , the auxiliary weight cylinder  42  is not joined to the weight cap  40  until after the weight cap  40  is assembled. Also, by using weight cylinders  42  of substantially constant diameters, a single version of a weight cap  40  may be manufactured to connect with any size of the weight cylinder  42 , thus decreasing manufacturing and inventory costs. In embodiments in which the shape of the weight cylinder  42  will not adversely affect manufacturability, the weight cylinder  42  may be unitary with the weight cap  40 . 
   In one form, the weight cap  40  has a first, proximal cylindrical section  44  and a second, distal cylindrical section  46  with a rear face  48 . Axial bores  52  extend proximally from the rear face  48 . The bores  52  may be internally threaded to capture ends of bolts  54 , or other attachment mechanisms may be used to secure bolts  54  in weight cap  40 . The second cylindrical section  46  may have a reduced diameter received in an annular flange, described below, in the weight cylinder  42 . A plurality, e.g. four, of axial bores  52  extends proximally from the rear face  48 . The weight cap  40  has a mating sleeve  62  projecting distally from the rear face  48  to be received in the axial bore  31  of the section  11 . An anti-rotation plug  64  may be provided extending distally from the mating sleeve  62  to be received in the anti-rotation socket  36 . A resilient washer  68  ( FIG. 7   a ) may be located at the interface of the weight cap  40  and the weight cylinder  42  to prevent relative axial motion or vibration within the weight collar  7 . In the present illustration the washer  68  is in a recess at a distal end of the weight cap  40 . Other vibration damping means, e.g. a gasket, could be used. 
   An axially extending central recess  66  ( FIG. 7   a ) extends through an interior portion of the weight cylinder  42 . A detent  70 , in a first position, extends radially beyond the mating sleeve  62 . The detent  70  cooperates with the circumferential groove  38  to maintain the weight collar  7  in engagement with the bar  2 . A retainer  72  renders the detent  70  captive in the mating sleeve  62 . In a preferred form, in manufacture of the weight cap  40 , an aperture  74  is provided in the mating sleeve  62  to receive the detent  70 . The area of the mating sleeve  62  in the vicinity of the aperture  74  is swaged to form the retainer  72 . 
   The weight cylinder  42  need not meet the mathematical definition of a cylinder. However, most practical embodiments of the weight cylinder  42  will meet the mathematical definition of a cylinder. In the present embodiment, the weight cylinder  42  has rounded edges at a distal end and has an annular flange  80  ( FIG. 5 ) which receives the rear section  46  of the weight cap  40 . Extending axially through the weight cylinder  42  are bores  50  positioned such that each bore  50  may be placed in registration with each bore  52  in the weight cap  40  and receive a bolt  54 . 
     FIG. 7  consists of  FIGS. 7   a - 7   c , each of which is a cross sectional elevation illustrating a different form of weight collar.  FIG. 7   a  represents the embodiment illustrated in  FIGS. 5 and 6 . The central axial chamber  66  extends from a proximal surface of the weight collar  7  sufficiently past to retainer  72  to permit housing of a distal end of actuator described below. An alignment socket  92  may be provided projecting distally from the central axial chamber  66 . 
   The central axial chamber  66  houses an actuator  100 . The actuator  100  is normally in a first position in which the detent  70  engages the circumferential groove  38 , as illustrated in  FIG. 7   a . When the actuator  100  engages the detent  70 , the weight collar  7  or the weight collar  8  will be locked on the bar  2 . When the actuator  100  is in a second position, the detent  70  will not engage any stop means, and the weight collar  7  or  8  will be released with respect to the bar  2 . The actuator  100  is preferably cylindrical. In the present illustration, the actuator  100  comprises a button  102   a  at a proximal end of the actuator  100  which has an expanded diameter with respect to a central section  104  to fit in the countersunk recess  94 . At a distal end, the actuator  100  may include an alignment plug  106  of reduced diameter with respect to the central section  104  received in the alignment socket  92 . 
   The actuator  100  includes a detent chamber  112  for each detent  70 . Each detent chamber  112  comprises first and second recesses  114  and  116 . The recesses  114  and  116  may be substantially hemispherical and conveniently formed by drilling. The depth of the first recess  114  has a dimension which will result in the detent  70  projecting through the aperture  74  ( FIG. 5 ) sufficiently to engage stop means such as the groove  38  ( FIG. 5 ). The second recess  116  has a depth dimensioned so that the detent  70  will not engage stop means and preferably not project radially beyond the sleeve  62 . A wall of the second recess  116  comprises a camming surface  118  to urge the detent  70  in a radial direction when the actuator  100  is moved from the second position to the first position. To maintain the actuator  100  in the first position when the actuator  100  is not being operated, a biasing means  108  is provided. In the present illustration, the biasing means  108  comprises a coil spring surrounding the alignment plug  106  and located in the central axial chamber  66  between a distal end of the central section  104  and a distal end of the central axial chamber  66 . 
   In the present embodiment, the proximal surface of the button  102   a  is distally displaced from the proximal surface of the weight collar  7 . A recess  119  is formed in the proximal end of the weight collar  7 . Positioning the button  102   a  in the recess  119  can help prevent accidental axial displacement of the actuator  100 , which could lead to disengagement of a weight collar  7  or  8 . Positioning of a proximal end of the actuator  100  is determined by the dimensions of the actuator  100 , the central axial chamber  66  and the location of the retainer  72  on the mating sleeve  62 . In each of  FIGS. 7   a - 7   c , a suffix is used on button  102  corresponding to the suffix of the Figure in which it appears.  FIGS. 7   b  and  7   c  illustrate different options for positioning an actuator  100  in the weight collar  7 . 
   In the embodiment of  FIG. 7   b , the button  102   b  has a diameter equal to that of the central section  104 . An annular member  103  may be press fit, or otherwise fastened over the end of the button  102   b  to fill the countersunk recess  94  and provide for a button the width of the button  102   b . In one embodiment, the annular member  103  could be a plastic collar. In one form, a different color plastic could be used for each different size of weight. In the embodiment of  FIG. 7   c , the components are dimensioned so that a button  102   c  projects from a proximal surface of a weight cap  40  surrounding the button  102   c  by, for example, 0.050″. In this embodiment, there is no countersunk recess  94 . 
     FIG. 8  is a cross sectional elevation in which a weight receives a bar, rather than a bar receiving a weight. The same reference numerals are used to denote components in earlier Figures. In the embodiment of  FIG. 8 , the end  16  of the section  11  terminates in a proximally extending cylinder  120 . The cylinder  120  has a circumferential groove  122  adjacent a proximal end thereof. The groove  122  will function in a manner similar to the circumferential groove  38  of the embodiment of  FIG. 5 . The weight cylinder  42  is formed with a first cylindrical recess  124  to receive a diameter of the end  16 . A second cylindrical recess  128  proximally extending from the first cylindrical recess  124  receives the extending cylinder  120 . The recess  124  extends beyond the proximal end of the weight cylinder  42  and is surrounded by a sleeve  126 . The sleeve  126  extends into a central area  129 . The central area  129  is defined by an inner diameter of the weight cap  40 . Threaded axial bores  130  in the weight cylinder  42  receive bolts  132  extending through axial bores  134  in the weight cap  40 . In this embodiment, assembly of an actuator is performed in the area proximally displaced from the weight cylinder  42 . Therefore, the weight cap  40  is assembled to the weight cylinder  42  after the remainder of assembly of a weight collar  7  or  8  is completed. The sleeve  126  has retainers  136 , i.e. apertures which will radially restrain detents  70 , positioned to be in axial registration with the circumferential groove  122  when the weight collar  7  or  8  is placed on the bar  2 . 
   In this embodiment, an actuator  140  is provided which is coaxial with and has a central axial recess receiving the sleeve  126 . An outer diameter of the actuator  140  has a radial dimension to fit in the inner diameter of the weight cap  40 . Biasing means, not shown, may be disposed in a space surrounding the sleeve  126  between a distal end of the actuator  140  and a proximal end of the weight cylinder  42 . Each detent chamber  112  is in the actuator  140  radially outwardly of the sleeve  126 . In order to place the detents  70  in each detent chamber  112 , radial bores  142  are formed. Plugs  144  fill each radial bore  142  to house the detents  70 . The plug  144  preferably terminates at its radially inward end in a hemispherical or otherwise scooped surface to receive the detent  70  and provide for camming as the actuator  140  is moved from the second position to the first. 
     FIG. 9  consists of  FIGS. 9   a - 9   e , each of which is a cross sectional elevation illustrating operation of the embodiment of  FIGS. 5-7   a . Operation of this embodiment is advantageous in that the weight collar  7  may be slipped on to the bar  2  without a user&#39;s having to depress the actuator  100 . However, the actuator  100  must be operated by a user to remove the weight collar  7 . In a steady state position, such as when the weight collar  7  is detached from the bar  2 , as illustrated in  FIG. 9   a , the weight collar  7  is in a first state. In the first state, the actuator  100  is in the first position. 
   When it is desired to secure the weight collar  7  to the bar  2 , the end  16  of the section  11  and the weight collar  7  are slid together. The edge  29  and then the inner wall  32  of the axial bore  31  engage the detent  70 , as seen in  FIG. 9   b . The force applied to the detent  70  by the end  16  in turn forces the detent  70  against the camming surface  118 . This force is greater than the force which urges the actuator  100  toward the first position applied by the biasing means  108 . The resulting camming action forces axial movement of the actuator  100  until the actuator  100  is in the second position, as seen in  FIG. 9   c . Once the actuator  100  is in the second position, the detent  70  is in registration with the aperture  74  and the groove  38 . Consequently, radially inward force is not transmitted to the detent  70 . At this point, the biasing force exerted by the biasing means  108  through the actuator  100  to the detent  70  is no longer overcome. Consequently, the biasing means  108  pushes the actuator  100  in the proximal direction, and the camming surface  118  pushes the detent  70  radially outwardly, as seen in  FIG. 9   d . The detent  70  projects through the aperture  74  and has a portion thereof received in the circumferential groove  38 . The circumferential groove  38  acts as stop means  37 . 
   In order to remove the weight collar  7 , a user applies force to press the actuator  100  against the biasing means  108 , as indicated in  FIG. 9   e . The actuator  100  moves axially from the first position to the second position. Consequently, the detents are no longer forced to engage the circumferential groove  38 . The user may slide the weight collar  7  off the bar  2 . Once the detents  70  are surrounded by the inner wall  32 , the user may stop applying force to the actuator  100 . 
   While it has been found that having the actuator  100  in the weight cap  40  may have some ergonomic advantages, if the coupling mechanism is housed in the bar  2 , then only one mechanism need be provided in conjunction with a plurality of weights. Also, since a coupling mechanism does not need to be assembled in the weight collar  7 , a one-piece weight collar  7  may be provided. The embodiment of  FIGS. 10-12  contains a coupling mechanism in the bar  2 .  FIG. 10  is an isometric view of a weight collar engaged with a bar.  FIG. 11  is an isometric view, partially broken away illustrating a further form of an end of a bar and a weight collar to be received on a bar in which the actuator is included in the bar rather than in the weight collar.  FIG. 12  is a cross sectional view of the apparatus of  FIG. 11  taken along a diameter of the bar and the weight collar. The same reference numerals are used to denote components corresponding to those in earlier embodiments.  FIGS. 10-12  are discussed together. 
   The weight collar  7  comprises a cylinder  150 . The cylinder  150  may have a stepped inner chamber  152  including a proximal section  154  and a distal section  156  which has a radial face  158  at a proximal end thereof. The proximal section  154  may have a radial cross section suited to act as an anti-rotation socket. A hexagonal cross section is a common choice. The distal section  156  comprises a circular bore for receiving the end  16  of the section  11 . The cylinder  150  may have a proximal recess  160  to allow distal displacement of an actuator from the proximal end of the weight collar  7 . The cylinder  150  has a first circumferential groove  162  positioned in the proximal section  154  of the stepped inner chamber  152  positioned to act as stop means for a detent  70 . Additionally, a secondary groove  164  is displaced distally from the circumferential groove  162 . The secondary groove  164  is a safety feature. If for some reason, detents  70  are not properly engaged in the circumferential groove  162 , the weight collar  7  may move axially and fall or be projected away from the bar  2 . The path of the detents  70  must traverse the secondary groove  164 . The secondary groove  164  can act as stop means to prevent separation of the weight collar  7  from the bar  2 . 
   In the present embodiment, the end  16  of the section  11  terminates in a hollow plug  170  having a radially outer surface fitting in the proximal section  154  of the stepped inner chamber  152  in the weight collar  7 . The wall of the hollow plug  170  comprises a sleeve  172 . The sleeve  172  may have a circular inner diameter defining a chamber  174  to house an actuator  176 . The sleeve  172  and actuator  176  interact in a manner similar to the interaction of the sleeve  62  and actuator  100  of  FIG. 6 . In the present embodiment, the actuator  176  further comprises an annular recess  180  extending proximally into the actuator  176  and surrounding the alignment plug  106 . In this manner, a longer spring may be housed within the sleeve  172  while utilizing the same axial dimensions for other components as in  FIG. 5 . 
     FIG. 13  consists of  FIGS. 13   a - 13   c , each of which is a cross sectional elevation in which structure and operation of an embodiment including a magnetic latch are illustrated. The same reference numerals are used to denote components corresponding to those in the embodiment of  FIGS. 10-12 . In the present embodiment, the sleeve  172  is not unitary with the section  11 . The sleeve  172  is a stepped sleeve having a reduced diameter distal end  190 . The distal end  190  has an alignment socket  192  which receives the alignment plug  106  and which is open at a distal end. In this embodiment, the alignment plug  106  is made of magnetically susceptible material or has an insert which will be attracted by a magnet. The depth of the alignment socket  192  is preferably selected so that a distal end of the alignment plug  106  is substantially in axial alignment with the open, distal end of the alignment socket  192  when the actuator  176  reaches its maximum distal displacement. 
   The sleeve  172  is slidable within and nests with a magnet-bearing sleeve  200 . The magnet-bearing sleeve  200  has a reduced diameter base  210  at a distal end thereof which will abut or be closely positioned next to the distal end  190  of the alignment socket  192  when the sleeve  172  reaches its maximum extent of distal movement with respect to the magnet-bearing sleeve  200 . The base  210  houses a magnet  212  at a proximal end thereof. In the latched position, the magnet  212  holds the actuator  176  in place, overcoming the force of the biasing means  108 . 
   The magnet-bearing sleeve  200  in turn is slidable in and nests with a stepped socket  220  in the end  16  of the section  11 . A biasing means  224 , such as a coil spring, is positioned to bias urging the magnet-bearing sleeve  200  in a proximal direction. The biasing means  224  may surround an alignment boss  218  projecting distally from the magnet-bearing sleeve  200 . 
     FIG. 13   a  illustrates an initial state prior to the weight collar  7  being placed on the bar  2 . The actuator  176  is either already in the latched state, or the actuator  176  is pushed distally by a user to be in the latched state. When the actuator  176  is in the latched state, it is in its second, i.e., disengaged, position. The magnet  212  engages and holds the alignment plug  106 . To secure the weight  7  to the bar  2 , the user slides the weight cylinder  150  coaxially and distally with respect to the end  16  of the section  11 . As the weight collar  7  is pushed distally with respect to the end  16 , a proximal radial face  158  of the distal section  154  of the inner chamber  152  approaches the magnet-bearing sleeve  200 . The magnet-bearing sleeve preferably has an inner diameter substantially equal to that of the inner, radial face  158 , as illustrated in  FIG. 13   b.    
   When the weight collar  7  and section  11  reach the relative position, as shown in  FIG. 13   b , the radial face  158  engages the magnet-bearing sleeve  200 . As the user continues to move the weight collar  7  axially distally, the face  158  pushes the magnet  212  away from the alignment plug  106 . When the magnet  212  reaches a preselected axial distance from the alignment plug  106 , the axial force applied by the biasing means overcomes the force exerted by the magnet  212 . At this point, the biasing means  108  urges the actuator  176  into the first position, illustrated in  FIG. 13   c . In the first position, the detents  70  engage stop means, e.g., the circumferential groove  162  in the weight collar  7 , and the weight collar  7  is secured to the bar  2 . 
   In order to disengage the weight collar  7 , a user  7  pushes the actuator  176  distally until the actuator  176  becomes latched, i.e., held in its second, i.e., disengaged, position, illustrated in  FIG. 13   a . Then the weight collar  7  may be conveniently slid off the bar  2 . 
     FIG. 14  is a cross sectional elevation an embodiment including an electromagnetic latch. In  FIG. 14 , the magnet  212  is an electromagnet. A power source  230 , e.g., a rechargeable battery, may be housed in a portion of the section  16 . A switch  234 , which, for example, may be a switch that toggles when depressed or which is on only when depressed. The electromagnet  212  may be energized to permit latching only in selected situations. 
     FIGS. 15 and 16  are respectively a front and a side elevation illustrating a weight support system  250  interacting with a set of weights. The weight support system comprises a mounting board  252  having a plurality of weight mounts  256  projecting therefrom. Each weight mount  256  is shaped to fit within a cylindrical envelope. The weight mount  256  receives a weight collar  7  or  8 . In one form, the weight mount  256  simulates an end of the bar  2  and may be coupled to a weight collar  7  or  8  in the same manner as a bar  2 , an example of which is shown as weight mount  260 . The weight support system  250  provides a reliable form of mounting weights and makes them accessible to users. The ease of utilizing the system  250  will encourage users at public exercise facilities to return weights to their proper place after use. Proper coupling of weights to the weight board  252  reduces the chance of accidental dropping of weights, thus providing additional safety in weight use. 
   The present subject matter being thus described, it will be apparent that the same may be modified or varied in many ways. Such modifications and variations are not to be regarded as a departure from the spirit and scope of the present subject matter, and all such modifications are intended to be included within the scope of the following claims.