Abstract:
An adjustable dumbbell featuring a handle containing an internal selection mechanism within series of nested weight units. The selection device is operated by a single action, in this case by turning a knob, which extends or retracts bars contained in the handle to attach a desired number of weight units to the handle.

Description:
REFERENCES  
       [0001]     U.S. Patent Documents  
                                           6,186,928   Mar. 19, 1999   Chen       6,196,952   Mar. 8, 1999   Chen       6,500,101   Aug. 11, 2000   Chen       6,228,003   Mar. 17, 1998   Hald et. al.       6,261,022   Feb. 9, 1999   Dalebout et. al.       5,637,064   Oct. 13, 1995   Olsen et. al.       5,769,762   Jun. 3, 1996   Towley et. al.       5,779,604   Mar. 4, 1996   Towley et. al.       6,083,144   May 4, 1999   Towley et. al.       5,971,899   Jun. 19, 1998   Towley et. al.       6,033,350   Sep. 29, 1997   Krull       5,839,997   Jan. 22, 1998   Roth et. al.                  
 
       FIELD OF INVENTION  
       [0002]     This invention relates to the exercise equipment field. It is focused toward free weights, utilizing weight-based resistance for exercise movements.  
       BACKGROUND OF THE INVENTION  
       [0003]     Traditional dumbbells and barbells have been used for over a century for building body strength and continue to be used for general fitness, strength and endurance training, and physical rehabilitation.  
         [0004]     There are two types of dumbbells: fixed and adjustable.  
         [0005]     Fixed dumbbells are typically one solid piece of metal with a handle in the center. Fixed dumbbells present a problem for storage in limited space, being that usually two of each weight increment takes up a significant amount of room. Each set must also be purchased separately, making an entire set rather expensive. A set of fixed dumbbells is also not very portable, specifically moving the entire set is very inconvenient.  
         [0006]     There are a variety of adjustable dumbbells designs, ranging from simple to very elaborate. Each of the existing designs has significant drawbacks. They stricken with one or more of the following problems: they take too much time to change weight, are not useable by someone with large hands, are unwieldy, are difficult to change weights, or pose a safety hazard.  
         [0007]     The initial designs for adjustable dumbbells included individual disc-shaped weights with holes in the center that would slide onto a round bar and secured to the handle by means of some sort of locking collar. These collars might screw on, use a spring clamp, or have a collar with a threaded locking pin. If the collars are loose or loosen during use, they pose a safety hazard because the weights can fall off the handle.  
         [0008]     Some innovative designs of adjustable dumbbells have appeared in the last decade. They use either an internal or external mechanism that attaches a desired number of weights to a handle. Although these designs show some promise, each has drawbacks and limitations.  
         [0009]     These limitations include such elements as: external selection mechanisms which pose a safety hazard, mechanisms that are limited in their function, mechanisms that are overly complicated, mechanisms that prohibit general usefulness or user comfort, devices that would not be reliable or sturdy, or some combination of the above. Some concepts that the present devices uses are mentioned in previously submitted material, but are not put together to make a safe, versatile, durable and user-friendly mechanism. There is room among these innovations for further advancement in design and application.  
         [0010]     The rack-and-pinion system is not a new technology. The present invention is unique in using not only the rack-and-pinion system, but combining it with a basic gear drive to extend the travel of the sliding elements, increasing the number of weights that the device may hold. This transmission system is also unique in that it further adds both safety and convenience of not having a users hand on the weight selection device during normal use.  
         [0011]     The present invention utilizes specific design features that ensure proper function. Unlike previous devices, the present devices contains all of the following features: a rack-and-pinion device contained within the handle, a basic transmission for maximum travel of extendable elements, mechanisms for locking extendable elements in each incremental position, indicator of currently selected weight, and nested weight units that have bars attached to the sides of the plates for required support.  
         [0012]     In summary, the present invention is the next generation of adjustable dumbbells, using both established concepts and new design features to create the simplest and safest adjustable dumbbell.  
       SUMMARY OF INVENTION  
       [0013]     The primary objective of the present invention is to provide a compact and easy to use weight lifting system that is not hindered by clumsy design or functional limitations.  
         [0014]     The present system involves a handle containing an internal rack-and-pinion mechanism within the grip for selectively attaching a desired number of weights to it. The present system also involves a series of nested weight units, each having two weight plates connected by bars along their outside edge. Each of these plates has holes for receiving the bars which extend from the handle to attach the weights to the handle.  
         [0015]     The bars that extend from the handle do so simultaneously by way of the rack-and-pinion. The first bar is driven by a gear connected by a shaft to a knob on top of the handle. Turning the knob extends or retracts both bars into or out of the holes in the weight plates, attaching or separating them from the handle as desired.  
     
    
     BRIEF DESCRIPTION OF FIGURES  
       [0016]      FIG. 1  shows a perspective view of the present invention.  
         [0017]      FIG. 2  shows a perspective view of the handle.  
         [0018]      FIG. 3  shows an exploded view of the mechanism within the handle.  
         [0019]      FIG. 4  shows a top cross-section view of the rack-and-pinion mechanism with the handle.  
         [0020]      FIG. 5  shows a cross-section view of the ball plungers.  
         [0021]      FIG. 6  shows a perspective view of a single weight unit.  
         [0022]      FIG. 7  shows an end view of a weight unit  FIG. 8  shows the first two weight units nested one inside the other.  
         [0023]      FIG. 9  shows a cross-section view of the holes through three consecutive weight units.  
         [0024]      FIG. 10  shows a bar that has not penetrated the hole in the weight unit.  
         [0025]      FIG. 11  shows a bar that has penetrated the hole in the weight unit.  
         [0026]      FIG. 12  shows a cutaway view of a handle being grasped by a hand. 
     
    
       [0027]     While the above-identified drawings set forth one embodiment, other embodiments of the present invention are also contemplated. This disclosure presents illustrative embodiments of the present invention by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this invention. The drawing figures are not drawn to scale.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0028]     Component List:  
         [0029]      1 . Handle Unit  
         [0030]      2 . Selection Knob  
         [0031]      3 . Extending Rods 
         3   a . Teeth          
         [0033]      4 . Endpiece  
         [0034]      5 . Grip  
         [0035]      6 . Drive Gear  
         [0036]      7 . Center Gear  
         [0037]      8 . Drive Axle  
         [0038]      9 . Spring Plunger 
         9   a . Ball      9   b . Spring          
         [0041]      10 . Indicator Window  
         [0042]      11 . Indicator Dial  
         [0043]      12 . Dial Drive Gear  
         [0044]      13 . Dial Reduction Gear  
         [0045]      14 . Dial Indicator Gear  
         [0046]      15 . Weight Unit  
         [0047]      16 . Weight Plate  
         [0048]      17 . Bar  
         [0049]      18 . Channel  
         [0050]      19 . Holes  
         [0051]      20 . Weights  
         [0052]      21 . Dimples  
         [0053]     As shown in  FIGS. 1-2 , a dumbbell system of the present invention is shown, which comprises of (i) a handle unit  1 , and (ii) a plurality of weights  20 . The handle unit  1  consists of a grip  5  containing an internal mechanism for extending and retracting two extending rods  3 , a selection device  2 , two endpieces  4 , and an indicator window  10  to display the currently selected weight.  
         [0054]      FIGS. 3-4  show the mechanism within the grip. The selection knob  2  turns the drive axle  8 , which turns the main drive gear  6 . The main drive gear  6  has gear teeth which engage rack teeth  3   a  the side of first extending rod  3 . A center gear  7  is turned by the first extending rod  3  when the main drive gear  6  is turned. The center gear  7  then drives the second extending rod  3  in the direction opposite the first extending rod  3  an equal distance.  
         [0055]     The handle unit  1  allows a user to turn the selection knob  2  to select how many weights  20  will be attached to the handle. The main drive gear  6  allows the extending bars  3  a range of travel up to half of their length.  
         [0056]     The drive axle  8  has dial drive gear  12  attached to it. Dial drive gear  12  turns dial reduction gear  13 , which in turn drives dial indicator gear  14 . This transmission gives the dial indicator gear  14  the correct travel to display numbers on the attached indicator dial  11 , visible through the indicator window  10  in the handle unit  1 .  
         [0057]     The grip  5  contains two spring plungers  9 , which fit into a series of dimples  21  on either extending rod  3 . These dimples  21  are positioned along the length of the extending rods  3  to snap the extending rods  3  into proper position for each weight unit  15  so that the extending rods  3  fill the holes  19  in the weight plates  16 .  FIG. 3  shows these spring plungers  9  in an exploded view.  FIG. 5  shows a cutaway view of the spring plungers  9  and how they fit into the dimples  21  in the extending rod  3 . Each spring plunger  9  has a ball  9   a  and a spring  9   b  which brings the ball  9   a  toward and into one of the dimples  21  on the extending rod  3 .  
         [0058]      FIG. 9  shows a sequence of three weight plates  16  with the holes  19  for accepting one of the extending rods  3 .  FIG. 10  shows the hole  19  in the weight plate  16  with the extending rod  3  not engaged.  FIG. 11  shows the extending rod  3  inserted into the hole  19  of the weight plate  16 . With the extending rod  3  in the hole  19 , the weight unit  15  is attached to the handle unit  1 .  
         [0059]     The weights  20  comprise of a series of nested weight units  15 , with each weight unit  15  fitting inside the next larger weight unit  15 .  FIG. 6  shows one weight unit  15 .  FIG. 8  shows one weight unit  15  sitting within another weight unit  15 . Each weight unit  15  is comprised of two weight plates  16  connected by at least one bar  17  along the outside perimeter.  FIG. 8  shows a side view of how each weight unit  15  is configured. The inside weight unit  15  is made up of two weight plates  16  attached by the bar  17 . The outside weight unit  15  is made up of two weight plates D attached by the bar  17 .  
         [0060]     Each weight unit  15  has two design features: (i) an angle θ, and (ii) an angle Φ[. Angle θ is shown in  FIG. 7  and provides easy replacement of the handle unit  1  and any weight units  15  attached to the handle unit  1 . Angle Φ is shown in  FIG. 8  also allows for the replacement listed above. Angle Φ may range from 1° to 5°.  
         [0061]      FIG. 12  shows a cutaway end view of the present invention&#39;s mechanism and configuration. The present invention&#39;s configuration provides a large amount of space for a user&#39;s hand and wrist to grip the handle  5 . There is enough room for a wrist to grasp the grip  5  from, for example, position A or B, or anywhere in between. There is even enough room for a user to place two hands on the grip  5 . There is also room for a user to grasp the grip  5  from the bottom, i.e. position C, or both the top and bottom. There are no additional supports required for housing functional mechanisms.  
         [0062]     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.