Patent Abstract:
This invention pertains to an improved adjustable kettlebell that has a stack of standard weight plates, a rounded grip section, a support bar serving to hold the weight stack, and flexible attachment members with cutouts for the support bar. The flexible attachment members provide a mechanically compliant clamping arrangement to accommodate weight stack of varying widths, and the cutouts allowing adjustment to the relative distance between the grip axis and the support bar axis. The improved adjustable kettlebell of the current invention serves as a close physical approximation to a solid cast kettlebell with a wide combination of standard weight plates.

Full Description:
This application claims the benefit of Provisional application Ser. No. 60/462,464, filed Apr. 11, 2003. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to exercise equipment. More particularly, this invention pertains to an adjustable kettlebell of an improved, compact design that can employ standard barbell plates. 
     BACKGROUND OF THE INVENTION 
     In the specification, “dumbbell” defines an exercise device with two weight sections, connected by a handle section, while “kettlebell” defines a single mass section (often spheroidal) attached to single looped handle section. While many exercises can be performed with both kettlebells and dumbbells, some motions are more comfortably performed with a kettlebell or provide a unique benefit that is distinct from the nearest dumbbell equivalent. However, several kettlebell exercises such as the one arm clean (OAC) and the one arm snatch (OAS) require a degree of technique to avoid the kettlebell bashing against the user&#39;s forearm. The impact force is confined to a relatively small contact area, and bruising and discomfort can often result. 
     Limitations of Existing Adjustable Kettlebell Designs 
     In both the OAS and OAC exercise motions, a solid kettlebell provides a rounded surface that distributes both the impact and resting load of the kettlebell&#39;s mass. The primary disadvantage of a solid kettlebell design is that several kettlebells of varying weights are required to accommodate a range of exercises and strength levels. Previous adjustable kettlebell designs have had deficiencies in that they employ nonstandard weights and/or fail to provide adequate roundedness and comfort in the final configuration. 
     A first adjustable kettlebell design was created by CALVERT (described in U.S. Pat. No. 1,316,683 issued to Milo Barbell Company). It comprises a handle attached to an outer shell surrounding a set of specialized weights. The following features and deficiencies of the design used in CALVERT are addressed by the improvements of the present invention. In CALVERT, (1) non-standard weight plates are required; and (2) the handle clearance, the distance between the handle and the point of contact between the forearm and the mass section, is fixed. 
     Another adjustable type of kettlebell design is WOOD (described in U.S. Pat. No. 1,917,566 issued to Robert Alfred Wood). WOOD describes four major configurations of prior art designs. WOOD describe a design with an accommodation for standard barbell plates inside of an outer shell. Wood discloses the two cups of the outer shell with the edges presented outwards. WOOD also discloses a continuous stack of plates secured by collars to a bar, all within the confines of the attachment member. In another configuration, WOOD discloses a modified form of the handle, assembled with several of the discs at each end of the bell configuration, the cup members being omitted. 
     WOOD does not reveal or describe several important features, namely, (1) a configuration that approximates the smooth surfaces found in the solid forged kettlebell without requiring a separate outer shell member; (2) a configuration where plates of the weight stack straddle the attachment members; (3) a configuration free of stop collars which avoids wide, awkward protrusions; and (4) a “solid” configuration that prevents sway of the main weight section with regard to the handle, along with an attachment mechanism that provides for an adjustable handle clearance. While WOOD contemplates a configuration with a solid handle (a wire bail), it does not describe a means to combine the solid handle with an adjustable handle clearance. Furthermore, adding additional chain links to the configurations described by WOOD will only increases the relative sway. 
     Another design for an adjustable kettlebell was implemented by GRACE (Gracefitness). It involves a gnurled handle, a set of specialized bevel discs, and a set of twisted steel bars functioning as a means of attachment between the weight discs and the gnurled handle. The following features and deficiencies of the GRACE design are addressed by the improvements of the present invention. GRACE requires (1) specialized beveled plates are required to form the rounded surface near the line of contact; (2) that the handle clearance is a fixed distance from the contact point; and (3) the plate axis is perpendicular the handle&#39;s axis, hence adjusting the number of weights changes the point of contact. 
     Two more adjustable designs that use standard barbell plates, are manufactured by Piedmont Design Associates (PDA). The deficiencies of the PDA designs are as follows: (1) the use of retaining collars results in significant gaps in the spacing of the weight plates that straddle the attachment member; (2) the use of retaining collars results in significant protrusions on the outside of the bell configuration; (3) the handle clearance between the handle and the bar is fixed. Another kettlebell design has been designed by IRONMIND (Ironmind). It implements the plate axis to be perpendicular to the handle axis, but requires careful consideration of the weight stack configuration to avoid having the weight plate edges come to rest with the forearm during some exercises. This design and instructions from manufacturers indicate their awareness of the shortcomings of this arrangement and discourage all exercise motions that involve the weight resting on the forearms. 
     SUMMARY AND OBJECT OF THE INVENTION 
     In light of the deficiencies, shortcomings and drawbacks of the known kettlebell designs, it is therefore an object to provide an improved kettlebell weightlifting device which includes an adjustable configuration that provides for a plurality of standard weight discs forming a weight stack with a central plate axis. 
     It is further object of the current invention to provide a supporting bar aligned along the plate axis, this axis being nominally parallel to the axis of the grip section of the handle. 
     It is another object of the current invention to provide a rounded grip section that affords comforting grip to the user. 
     It is also an object of the current invention to provide attachment members that afford significantly reduced gaps between weight discs that straddle said attachment sections. 
     It is further desirable that these attachment members are structured as to provide an adjustable distance between the grip section and the plate axis. 
     These and other objectives, characteristics and advantages of the present invention will be disclosed in more detail with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a partially exploded elevation view of one embodiment of the present invention. 
         FIG. 1B  is a side view of an implementation of an attachment member illustrated in  FIG. 1A  from the perspective of reference character AA. 
         FIG. 1C  is a side view of another implementation of an attachment member illustrated in  FIG. 1A  from the perspective of reference character AA. 
         FIG. 2  is an elevation view of the present invention highlighting the flexure of the attachment structure. 
         FIG. 3  is a side view of one embodiment of the present invention, showing the rounded handle, weight discs, and the “forearm”. 
         FIGS. 4A–4C  are a schematic representation of the present invention, showing three additional configurations in accordance with the current invention, showing a narrow configuration with large plates and hemispherical end caps in FIG.  4 A, a narrow configuration with small plates and hemispherical end caps in  FIG. 4B , and a narrow configuration with small plates, hemispherical end caps and a protective band in  FIG. 4C . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1A  shows an elevation view of one embodiment of the present invention in partial disassembly. A curved and rounded handle assembly is comprised of a grip section  1  and an attachment member or “blade”  14 . The “blade”  14  has an asymmetric cross-section and intersects the stack of disc weights  18  with a minimal gap  16  introduced between weight plates. For example, the attachment member in  FIG. 1A  illustrates an asymmetric cross-section, wherein the attachment member is formed with a cross-section that has a greater breadth in a direction perpendicular to a weight plate axis than in a direction parallel to the weight plate axis. The subassembly of the bolts  34 ,  35 , washers  91  and the elongated nut  28  forming a support bar  70  for the weight stack. 
     In this particular embodiment, an elongated hexnut  28  with a captive washer  90  welded to one end, is passed through a central disc stack  96  from the left until the captive washer  90  meets the outside face of the left blade, while the right bolt  35  is passed through an outside washer  91  and rightmost weight assembly  92  and threaded into the hexnut  28  from the right, and the left bolt  34  is passed through the leftmost weight assembly  94  and threaded into  28  from the left. As the bolts are tightened down, the gap  88  between the outside weight assemblies  94  and  92  and center weight stack  96  reduces to the thickness of the attachment members  14 —the final configuration forming a single, physically tight assembly. The subassembly of the bolts  34 ,  35  and the elongated hexnut  28  forming a support bar  70  assembly for the weight stack. Section AA # 1  shows the cross section of the blades  14  with distinct holes  20  for different positions of the bar. Section AA # 2  shows the cross section of the blades  14  with a scalloped hole pattern  22  that provide for a finer adjustment of support bar positions. The adjustable hand clearance  98  feature is demonstrated with the center line  24  aligned with holes AA # 1 , and the center line  25  aligned with sections AA # 2 . Distinct holes  20 , or small nibs  23  in the hole pattern  22  can provide a hard mechanical stop for the hexnut  28 . Alternately, the design can rely solely on the friction of a tightened support bar to set and maintain a specific handle clearance  98 . 
     In  FIG. 1A , the support bar  70  is comprised of the left bolt  34 , elongated nut  28  with captive washer  90  and right bolt  35 . With various combinations of outside bolts ( 34  and  35 ) and a 4″ long hexnut  28 , the length of the support bar can safely span a range of 4″ to 10″. Other features of this invention may include the following additional elements:
         1) since the captive washer  90  provides access to the internal thread of the hexnut  28 , the right weight assembly  92  can be modified without rearranging either the core  96  or the left weight assembly  94 ;   2) additional combinations of inside and outside bolts can provide additional lengths, if necessary;   3) either or both outside weight assemblies may be omitted.       

     Alternately, the support bar can be configured as a variety of other mechanical arrangements that effectively result in a shaft of adjustable length. Moreover, a support bar can be comprised of a solid or hollow tube along with standard securing mechanisms, such as spring, spiral clamps or large pitch spiral threads, with the proviso that such configurations can introduce additional protrusions past the outside weight assemblies. 
     By defining an attachment member  10  with various hole configurations of  20  or  22  (see  FIG. 1A–1C ) the present invention allows for an adjustment of the distance between support bar  70  axis  24  and the grip axis, and provides the key improvement that the user can adjust the optimum contact point  32  independently of the diameter of the weight plates that are used. 
       FIG. 2  illustrates another aspect of the present invention. The blade section  14  is part of a single piece of bent spring material  74  (preferably spring steel), that is embedded in a partially hollow grip-section  1  with outside profile  82 . In the implementation in  FIG. 2 , because the attachment members are formed from a springy material, the attachment members have an inherent resilient mechanical compliance, as well as an asymmetric mechanical compliance. Further, in the  FIG. 2 , a bar  74  is bent to a profile that fits snugly against the internal webs  80  of an otherwise hollow grip section  1  which could be constructed by joining two halves of either stamped metal or molded material (for example, ABS plastic). The internal webs  80  function to secure part of the bar member  74  between pivot points  76 . In the implementation in  FIG. 2 , the attachment members are formed with an internal pivot point  76 . Below the pivot points  76 , there is an internal clearance  98  that allows the bar  74  to flex within the hollow grip-section  1 . 
     As the bolt  35  is threaded against the elongated hexnut  28 , the blades  14  flex into a new profile  78 . Additionally, if the nominal hex pattern  22  is cut into the blade attachment members  14 , then the hexnut  28  can be restrained from spinning even if the core weight stack  96  width is greater than the hexnut&#39;s length. This safety feature prevents the inadvertent loosening of one bolt while the user tightens the other bolt. Additionally, by setting the pivot point  76  far from the bottom of the grip-section  1 , the present invention achieves greatly increased mechanical compliance of the blades  14 , allowing the blades to clamp tightly against a central plate assembly  96  of varying width without excessive stress being placed on the blades or the grip-section  1 . 
       FIG. 3  shows the side view of the kettlebell configuration, with a grip-section  1  leading into the attachment member blades  14  that intersperse the weight stack. The inner stack of weights is comprised of larger weight discs  18  (e.g., 10 pounds), while the outer edges of the stack are comprised of smaller weight discs  17  (e.g., 5 pounds). 
     In this view, the contact point  32  between the forearm  40  and the weight stack shows the critical nature of the hand clearance (the distance between the support bar axis  24  and the grip axis). If this clearance is too small then the weight&#39;s leverage against the wrist can impose excessive pressure at the contact point. If this clearance is too large, then the flipping action (described in the OAS and OAC motions above) of the kettlebell allows for excessive acceleration of the weight stack prior to terminating at the contact point  32 . 
       FIGS. 4A–4C  show some additional configurations of the present invention. Configuration  64  in  FIG. 4A  shows a weight stack comprised of four ten pound discs  18  along with hemispherical end caps  48  all aligned on centerline axis  44 . The hemispherical end caps  48  would have a deep countersunk hole that would allow for bolt head and support bar (not shown in this drawing) to pass through the majority of the hemispherical end cap. The final configuration nearly approximates the hemispherical shape of the original solid kettlebell. The hemispherical end caps could be made of any material. A metal cap would provide additional weight, while caps made of plastic, foam, wood or other light material provide the desired shape without significant addition weight or requirement for a specialized forging. 
     Configuration  66  in  FIG. 4B , shows a weight stack comprised of four 5 pound discs  17  along with smaller hemispherical end caps  49  all aligned on centerline axis  46 . Substantially less weight is involved (20 vs 40 pounds), but the optimal contact point is preserved by adjusting the centerline  46 . The smaller hemispherical end caps  49  have all the characteristics of their larger counterparts  48  in configuration  64 . 
     Configuration  68  in  FIG. 4C , shows a weight stack comprised of four 5 pound discs  17  along with the larger hemispherical end caps  48 , and a protective band  50  around the weight stack, all aligned on centerline axis  44 . The weight stack of  17 , spherical end caps  48  and protective band  50  comprising an entirely spheroidal shape of relatively low weight and large size, are envisioned for the less aggressive user. The hemispherical caps and/or protective band can be manufactured out of a dense shock absorbing foam for additional comfort and protection. 
     While there have been shown and described, pointed fundamental novel features of the invention as applied to embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the invention, as herein disclosed, may be made by those skilled in the art without departing from the spirit of the invention. In particular all weights and dimensions introduced in the specification were presented for illustrative purposes, and variations in said weights and dimensions are anticipated and will not affect the utility of the present invention. It is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. It is the intention, therefore to be limited only as indicated by the scope of the claims appended hereto.

Technology Classification (CPC): 0