Abstract:
A dumbbell system is provided including a base weight member having a ring-shaped body and a handle extending across an opening in the ring-shaped body. A plurality of weight rings are adapted to be removably mounted to the base weight member in order to provide a compact dumbbell system which has the capability of providing several weight increments in a compact assembly. The dumbbell system is ideal for use in areas where space is limited. The dumbbell also provides for a unique balanced mass arrangement which alleviates undesired stresses on a user&#39;s wrist.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to dumbbells for weight lifting, and more particularly to a dumbbell system with improved ergonomic design and which allows for the simple addition of additional weights to a base dumbbell member in a compact design. 
     BACKGROUND 
     Studies have shown that exercise greatly reduces the risk of heart disease and other ailments, and also contributes to better overall health and well being. Weight lifting has been determined to be a very important part of a well balanced exercise regimen. Accordingly, people are joining health clubs and purchasing home gym equipment in order to improve their physical fitness. 
     Health clubs typically have several racks of non-stackable dumbbells of varying weight which range from five pounds to approximately 120 pounds in five-pound or similar increments. The racks to hold all of the dumbbells in the five-pound to 120-pound sets are typically several feet long. Because such sets of dumbbells are extremely expensive and consume a lot of space, these sets are not well designed for home use. 
     Dumbbells have been designed for home gym use to include a bar having a center sleeve portion which defines a handle and weight discs which are removably attached to each end of the bar by a locking collar. A problem with these prior art designs is that it is still necessary to maintain a full set of disc weights which can be placed on the ends of the dumbbell bar. Furthermore, it is time consuming to put the weights on and take the weights off from this type of dumbbell design. The locking collars are also a safety hazard if they are not properly secured in place. In addition, with the weights being disposed at each end of the dumbbell, the moment arm which is applied to a user&#39;s wrist if the dumbbell is not maintained in a horizontal plane can result in painful stresses to the wrist joint of the user. Similar painful stresses are present with standard one-piece dumbbells. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a dumbbell system which is capable of providing several increments of weight in a compact construction. 
     It is another object of the present invention to provide a dumbbell system which provides equally distributed weight around the handle of the dumbbell assembly so that rotation of the handle away from a horizontal position does not result in undesirable added stresses on the user&#39;s wrist. 
     These and other objects of the present invention are obtained by providing a dumbbell system including a base weight member including a ring shaped body and a handle extending across an opening in the ring shaped body. A weight ring is adapted to be removably mounted to the base weight member. A lock ring is engagable with the weight ring to securely mount the weight ring to the base weight member. The weight ring includes a first mating portion, and the lock ring includes a second mating portion which is adapted to be engaged with the first mating portion of the weight ring for securing the weight ring to the lock ring. The base weight member has an outer perimeter surface with a pair of angularly disposed edge portions while the weight ring includes an inner surface with at least one angularly disposed edge portion which engages one of the pair of angularly disposed edge portions of the base weight member. The locking ring includes an angularly disposed inner surface which engages the other of the pair of angularly disposed edge portions of the base weight member. 
     A series of additional weight rings are adapted to be removably mounted to one another in order to provide variable increments of weight. The base weight member as well as the additional weight rings can be nested together in a single assembly and the lock rings can be selectively engaged or disengaged from the weight rings in order to allow the user to select from a plurality of weight increments. The lock rings can be provided with a plurality of dimples on a face surface thereof in order to facilitate rotation of the lock ring relative to the corresponding weight ring so that the lock ring can be easily engaged or disengaged from the weight ring. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a top view of a dumbbell assembly according to the principles of the present invention; 
     FIG. 2 is a side view of the dumbbell assembly shown in FIG. 1; 
     FIG. 3 is an exploded perspective view of the dumbbell assembly according to the principles of the present invention; 
     FIG. 4 is a detailed view taken along line  4 — 4  of FIG. 1 illustrating the insertion of the locking tab into the slot of the locking ring according to the principles of the present invention; 
     FIG. 5 is a cross-sectional view taken along line  5 — 5  of FIG. 1 illustrating the locking tab engaged with the slot of the lock ring according to the principles of the present invention; 
     FIG. 6 is a detailed view of the circled area  6  of FIG. 2 illustrating the serrations on the face surface of the dumbbell system of the present invention; 
     FIG. 7 is a cross-sectional view along line  7 — 7  of FIG. 1; 
     FIG. 8 is a detailed perspective view of the slot provided in the lock rings according to the principles of the present invention; 
     FIG. 9 is a detailed perspective view of the locking tabs which are engagable with the slot in the lock ring; 
     FIG. 10 is a top view of a weight disk system according to the principles of the present invention; 
     FIG. 11 is a schematic view of a standard 40 pound dumbbell for purposes of illustrating the moment forces; 
     FIG. 12 is a cross sectional view of a 40 pound dumbbell having angled interior edges according to the present invention for purposes of illustrating the moment forces; and 
     FIG. 13 is a cross sectional view of a ring shaped 40 pound dumbbell for purposes of illustrating the moment forces. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the accompanying drawings, a dumbbell assembly  10  of the present invention will now be described. The dumbbell assembly  10  includes a base weight member  12  including a body portion  14  defining a central opening  16  extending therethrough and including a handle  18  which extends across the opening  16  in the body portion  14 . According to a preferred embodiment, the body portion  14  is ring shaped. A first weight ring assembly  20  is removably mounted to the base weight member  12 . A second weight ring assembly  22  is adapted to be removably mounted to the first weight ring  20 . A third weight ring assembly  24  is adapted to be removably mounted to the second weight ring assembly  22 . 
     As mentioned above, the body portion  14  of the base weight member  12  is preferably ring shaped. As best shown in the cross-sectional view of FIG. 7, the body portion  14  of the base weight member  12  includes an outer perimeter surface  28  with a pair of angularly disposed edge portions  30 ,  32 . The angularly disposed edge portions  30 ,  32  extend radially inward. It should also be noted that the inner perimeter surface of the body portion  14  is also provided with angularly disposed edge portions  34 ,  36  which extend radially outward. The angularly disposed edge portions  34 ,  36 , which are disposed on the inner perimeter surface of the body portion  14  allow for easier access of a user&#39;s hand and helps to avoid interference with a user&#39;s wrist or forearm while the dumbbell assembly  10  is in use. Additionally, the angularly disposed edge portions  34 ,  36  allow for a reduction of the inner diameter opening of the handle  18 , hence reducing the overall size of the dumbbell assembly  10  and hence, also reduces the torque moments over a standard cylindrical weight. 
     A standard dumbbell free weight comprised of two equal weights, typically hexagonal in shape, attached and separated by a cylindrical handle 5.0 to 5.5 inches long. If a fulcrum is placed at the center of the handle, then the dumbbell is balanced like a see-saw and equal and opposite torques, i.e. moment x weight, are applied at both ends of the dumbbell. These torques for a typical 40-lb. weight are 90.2 inch-lbs. (see FIG.  11  and Equation [1] below). If the same 40 lb. free weight is made with a cylindrical configuration which includes angled edges within the gripping opening, then the left and right side torques calculate to be 32 in-lbs. (see FIG.  12  and Equation [2] below). That is approximately 35% of a standard dumbbell. If on the other hand the cylindrical 40 lb. free weight is made from a cylinder of equal height with no angled edges, then the torques at the left and right hand sides calculate to be 37 in-lbs. (see FIG.  13  and Equation [3] below). That is 41% of a standard dumbbell but 15% greater than the cylindrical weight with angled edges within the gripping opening. The equations for each of the above calculations is shown below. 
     
       
         torque=19.5×(5.5/12+3.75/2)=90 inch-lbs.  [1] 
       
     
     
       
         torque=39/4×3.375=32.1 inch-lbs  [2] 
       
     
     
       
         torque=39/4×3.8125=37.2 inch-lbs.  [3] 
       
     
     The base weight member  12  can be nested with a plurality of weight rings such as weight ring assemblies  20 ,  22 ,  24 . The first weight ring assembly  20  includes first weight ring  40  and first lock ring  42 . The first weight ring  40  includes an inner surface  44  with an angularly disposed edge portion  46  which extends radially inward and corresponds with the angularly disposed edge portion  30  of the base weight member  12 . The first weight ring  40  also includes a mounting ring  48  fixedly attached to a body portion of the weight ring  40 . The mounting ring  48  includes a plurality of mating portion  50  in the form of locking tabs. The lock ring  42  includes a plurality of corresponding mating portions in the form of slots  52 . The locking tabs  50  extend vertically upward from the mounting ring  48  and have an uppermost portion  50   a  which extend radially outward as best shown in FIGS. 5,  7 , and  9 . The slots  52  disposed in the lock ring  42  include a first recess portion  54  which is adapted to receive the radially outward extending portion  50   a  of the tab  50 . The slot  52  also includes a flange portion  56  which, upon rotation of the lock ring  42  relative to the weight ring  40 , receives the radially outwardly extending portion  50   a  of the locking tabs  50  as shown in FIG. 5 in order to engage the lock ring  42  to the first weight ring  40 . 
     The first weight ring  40  also includes an outer perimeter surface  60  with an angularly disposed lower edge portion  62 . The lock ring  42  includes an angularly disposed outer surface  63  and an angularly disposed inner surface  64  which engages the upper angularly disposed edge portion  32  of the base weight member  14 . The angularly disposed edge portions  30 ,  32  of the base weight and the angularly disposed lower edge portions of the weight rings and the angularly disposed surfaces of the lock ring are preferably greater than approximately 7 degrees to avoid locking or wedging of the elements together. The larger the angle, the easier the elements go together and come apart. An angle of 20 degrees has been found to effectively satisfy manufacturing anti-locking characteristics. 
     The second and third weight ring assemblies  22 ,  24  are identical in design to the first weight ring assembly  20  but are simply larger in size such that the first weight ring assembly can be nested inside the second weight ring assembly and the second weight ring assembly  22  can be nested radially inward of the third weight ring assembly  24 . Specifically, the second weight ring assembly  22  includes a second weight ring  70  and a second lock ring  72  and the third weight ring assembly  24  includes a third weight ring  74  and a third lock ring  76 . Each of the weight ring assemblies  20 ,  22 ,  24  is designed with a sufficient tolerance to allow mating with one another to prevent locking. 
     The second and third weight rings  70 ,  74  each include a mounting ring  48  with tabs  50  as described above with respect to the first weight ring  40 . The mounting rings  48  are mounted to the body of the first, second, and third weight rings  40 ,  70 ,  74  by screws or by other fastening techniques such as adhesives. The mounting rings  48  are preferably made of injection molded plastic while the body portion of the first, second, and third weight rings  40 ,  70 ,  74  are preferably made of case metal, although other materials exhibiting the desired weight characteristics can also be utilized. The second and third lock rings  72 ,  76  are also provided with slots  52  similar to the slots  52  provided in the first lock ring  42 . The first, second, and third lock rings  42 ,  72 , and  76  are preferably made of a plastic material. The use of a combination of materials as discussed above allows for several advantages. Since the plastic components can be made with high precision and the cast metal components can be made at low cost, the assembly as a whole can be manufactured at low cost while the use of the plastic components (mounting rings and lock rings) allows the assembly to be manufactured with high tolerance so as to have a refined operation and appearance. 
     In operation, the dumbbell assembly  10 , according to the principles of the present invention, is laid out in the manner shown in FIG.  1 . As is well understood, a pair of dumbbell assemblies  10  is often used during a workout. Initially, it should be noted that the base weight members  12  can be provided with a selected amount of weight such as, for example, 15 pounds or 20 pounds. Then, each of the weight ring assemblies  20 ,  22 ,  24  can weigh, for example, 10 pounds so that the base weight member  12  used alone can provide, for example, a 15-pound or 20-pound weight while the addition of the first weight ring assembly  20  will allow the use of a 25-pound and 30-pound dumbbell, and the addition of the first and second weight ring assemblies  20 ,  22  will provide a 35-pound and 40-pound dumbbell and the use of the first, second, and third weight ring assemblies  20 ,  22  and  24  would provide a 45-pound and 50-pound dumbbell. The base weight members of 10, 15 or 20 pounds are designed so that their outer perimeters are identical and can readily accept the weight ring assemblies  20 ,  22  and  24 . 
     By selectively disengaging the third lock ring  76  from the third weight ring  74 , the dumbbell assembly  10  can be picked up by handle  18  and the first and second weight ring assemblies  20 ,  22  would be picked up along with the base weight member  12  while the third weight ring  74  would remain on the floor. Similarly, removal of the second and third lock ring  72 ,  76  from the second and third weight rings  70 ,  74  by rotation of the lock rings in the direction of arrow B would allow the first weight ring assembly  20  to be maintained with the base weight member  12  but freed from the second and third weight ring assemblies  22 ,  24 . In addition, removal of all of the lock rings  42 ,  72 ,  76  would allow the base weight members  12  to be utilized alone in order to provide the smallest increment of weight for the dumbbell assembly  10 . 
     In order to facilitate holding the first, second, or third weight rings  40 ,  70 ,  74  from rotating with the rotation of the corresponding lock ring  42 ,  72 ,  76 , the bottom face surfaces of the first, second, and third weight rings  40 ,  70 ,  74  can be provided with a serrated surface  80  such as shown in FIG.  6 . The serrations would act to provide a frictional contact with the floor to prevent the weight rings from rotating when the lock rings are engaged or disengaged. Alternatively, the bottom surfaces of the weight rings  40 ,  70 ,  74  can also be provided with a rubberized coating which would provide additional friction between the floor or other surface to provide means for preventing rotation of the weight rings when the lock rings are being rotated for engagement or disengagement from the weight rings. Additionally, a rubber mat  82  may also be utilized as shown in FIG. 3 for providing this function. The first, second, and third lock rings  42 ,  72 , and  76  can also be provided with a plurality of dimples  84  on an upper surface thereof in order to facilitate a user&#39;s gripping the lock rings for rotation relative to the weight rings. 
     It should be noted that although the dumbbell assembly  10  of the present invention has been illustrated as a ring-shaped design, other shapes may be utilized without departing from the spirit and scope of the present invention. In particular, oval, square, or rectangular shaped members could be utilized in a similar nested fashion with different types of mating portions being required on the locking members for securing the additional weights to the base weight member. In addition, the above example was illustrated with three weight ring assemblies being added. It should be understood that any number of weight ring assemblies can be utilized so long as the size of the dumbbell system does not become too large and cumbersome for the user. 
     In order to provide even greater versatility with the dumbbell system of the present invention, a universal component may also be introduced to a single master member in order to provide for the addition of, for example, five-pound increments. This can be accomplished, for example, by providing a single heavier weighted lock ring to replace the innermost lock ring  42  which is lighter weight and made of plastic. The heavier weighted lock ring can be made of, or filled with, a heavier material then the lock ring  42 . Alternatively, other methods of mounting an additional weight may be utilized. 
     The nested arrangement of the weight system of the present invention can also be utilized for providing variable weight disks  100  (shown in FIG. 10) for use with a standard barbell in the same manner that conventional weight disks are utilized. In this arrangement, the base weight member  102  is provided with a smaller central hole  104  which is adapted to receive a barbell therethrough. The first, second, and third weight ring assemblies  20 ,  22 ,  24  are removably mounted to the base weight member  102  in the same manner as described above with respect to the dumbbell system  10 . Thus, the disk weight assembly  100 , provides a compact design to provide several increments of weight in the space of a single disk. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.