Abstract:
A rotary dumbbell of the present invention includes a handle, and two pairs of wheels and weight devices pivoted on opposite ends of the handle for rotation. Each of the wheels has a center pivoted on the handle and is unadjustable in a radial direction thereof that the wheels centrally rotate. Each of the weight devices is adjustable in a radial direction thereof that the weight devices may eccentrically rotate. The dumbbell further includes two pairs of covers to hold the weight devices and the wheels respectively. Therefore, user may get an extra loading because of the eccentric rotation of the weight devices when he/she shakes the dumbbell. The dumbbell may be used as a roller to train abdominal muscles while the wheels serve the function of rollers.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to a training apparatus, and more particularly to a rotary dumbbell. 
         [0003]    2. Description of the Related Art 
         [0004]    Recently, physical fitness has already become one of the common leisure activities. People usually go to gym to exercise because some huge and expensive fitness apparatuses are equipped in the gym only. However, not every person has the time and the money to spend at a gym, so that people buy some simple and inexpensive fitness apparatuses for use at home. 
         [0005]    Dumbbell is one of the most popular fitness apparatus to provide a wide variety of exercises such as biceps curls, triceps extensions, and the like. Dumbbells are commonly found in gyms, as well as for sale to private users because they are small, simple and cheap for ordinary people to exercise. 
         [0006]    Typically, the conventional dumbbell usually has two weight-heads attached to opposite ends of a handle bar. A full set of such dumbbells includes various pairs of dumbbells with different weights that user may choose the specific dumbbells according to his/her particular physical condition and exercise needs. 
         [0007]    Taiwan utility patent no. M385377 taught an improved dumbbell, which has a handle tube, an axle inserted into the handle tube, two bearings fixed in the handle tube to support the axle that the axle may rotate freely, and two weight devices fixed to opposite ends of the axle. The weight devices will rotate when user holds the handle tube and shakes the dumbbell. The most important thing is that the weight devices are eccentric that the eccentric rotation of the weight devices will provide an extra loading when user shakes the dumbbell. However, this eccentric dumbbell always provides eccentric rotation. The eccentric rotation of the weight devices of the dumbbell is uncontrollable and may hurt user when the user takes the eccentric dumbbell as the ordinary dumbbell to exercise. 
       SUMMARY OF THE INVENTION 
       [0008]    The primary objective of the present invention is to provide a rotary dumbbell, which is adjustable to have different eccentric loadings. 
         [0009]    The secondary objective of the present invention is to provide a rotary dumbbell, which has another function to exercise except for the normal training mode of dumbbell. 
         [0010]    To meet the objectives, a rotary dumbbell of the present invention includes a handle and two pairs of wheels and weight devices pivoted on opposite ends of the handle for rotation. Each of the wheels has a center pivoted on the handle and is unadjustable in a radial direction thereof that the wheels centrally rotate. Each of the weight devices is adjustable in a radial direction thereof that the weight devices may rotate eccentrically. 
         [0011]    Therefore, user may get an extra loading because of the eccentric rotation of the weight devices when he/she shakes the dumbbell. The dumbbell may be used as roller also to train abdominal muscles while the wheels serve the function of rollers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a preferred embodiment of the present invention; 
           [0013]      FIG. 2  is an exploded view in a part of the preferred embodiment of the present invention; 
           [0014]      FIG. 3  is a sectional view of the wheel of the preferred embodiment of the present invention; 
           [0015]      FIG. 4  is a sectional view of the weight device of the preferred embodiment of the present invention; 
           [0016]      FIG. 5  is a sketch diagram of the preferred embodiment of the present invention, showing the weight device moving to an eccentric position; 
           [0017]      FIG. 6  is a perspective view of the preferred embodiment of the present invention, showing user training with the dumbbell in an eccentric mode; 
           [0018]      FIG. 7  is perspective view of the preferred embodiment of the present invention, showing user training with the dumbbell in a normal mode; 
           [0019]      FIG. 8  is a sketch diagram, showing the user using the dumbbell of the present invention for abdominal training. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    As shown in  FIG. 1 , a rotary dumbbell  100  of the preferred embodiment of the present invention includes a handle  10 , on opposite ends of which two wheels  30  and two weight devices  40  are pivoted. 
         [0021]    As shown in  FIG. 2 , the handle  10  is a tubular member with an axle  12  passing there through. Two bearings  11 , only one of which is shown in  FIG. 2 , are mounted in the opposite ends of the handle  10  to support the axle  12  that the axle  12  may rotate freely relative to the handle  10 . The axle  12  has two connecting portions  14  at opposite ends, each of which has two flat surfaces  15 . The connecting portions  14  of the axle  12  extend out of the handle  10  to connect the wheels  30  and the weight devices  40 . In other words, the wheels  30  and the weight devices  40  have the same rotation axis which is the axle  12 . 
         [0022]    Two pairs of first covers  20  and second covers  50  are respectively fitted to the opposite ends of the axle  12  in sequence. Between each pair of the first cover  20  and the second cover  50 , the wheel  30  and the weight device  40  are provided. The first cover  20  has a cavity  21  at a center of an outer side and a hole  22  at a bottom of the cavity  21 . The first cover  20  further has three posts  23  projected from an inner side thereof with plural of ribs  24  at bottoms respectively. The axle  12  passes through the hole  22  of the first cover  20 , and an end of the handle  10  is received in the cavity  21 . A C-ring  13  engages the axle  12  at the inner side of the first cover  20  that the first cover is coupled to the axle  12 . The second cover  50  is a disc-like member, and has a cavity  51  at a center thereof and a hole at a bottom of the cavity  51 . 
         [0023]    As shown in  FIG. 2  and  FIG. 3 , the wheel  30  has a case  32 , in which weight members  31  are received. The case  32  consists of a box  34  and a lid  38 . The box  34  has an open end  33 , and the lid  38  seals the open end  33 . Three pairs of posts  35  are projected from a bottom of the box  34 , and the lid  38  has six bores associated with the posts  35  respectively. Each of the weight members  31  has two holes to be fitted to the posts  35  respectively. The lid  38  covers the box  34  with screws screwing into the posts  35  through the bores of the lid  38  that the weight members  31  are fixed in the case  30 . A hub  36  is provided at a center of the box  34 , and the lid  38  has an opening  381  at a center in association with the hub  38 . The hub  36  has a connecting hole  361  which is complementary to the connecting portion  14  of the axle  12 . The box  34  further has three tubes  37  between each pair of the posts  35 , and the lid  38  has holes in association with the tube  37  respectively. Each tube  37  has a hole  371  to be engaged with the post  23  on the first cover  20 . Screws are screwed into the lid  38  to fasten the posts  23  received in the holes  371  of the tubes  37  that wheel  30  is fixed to the first cover  20  and is engaged with axle  12 , therefore the wheel  30  and the first cover  20  rotate along with the axle  12 . 
         [0024]    It is noted that the weight members  31  are divided into three stacks, and the connecting hole  361  of the case  30  is located at a center of gravity of the weight members  31 . That is, the wheels  30  will centrally rotate. 
         [0025]    As shown in  FIG. 2  and  FIG. 4 , the weight device  40  has a case  42 , consisting of a box  44  and a lid  48 , and plural of weight members  41  received in the case  42 . The case  42  is the same as the case  32  of the wheel  30  in diameter and thickness. Same as above, the box  44  has an open end  43 , and the lid  48  seals the open end  43 . The box  44  has three pairs of posts  45  projected from a bottom thereof, and each weight members  41  has two holes to be fitted to the posts  45 . Screws are screwed into the posts  45  through the lid  48  to fix the box  44 , the lid  48  and the weight members  41  together. The box  44  has an elliptical tube  46  with an elongated adjusting slot  47 , and the lid  48  has an elliptical fitted to the elliptical tube  46 . The adjusting slot  47  extends in a radial direction of the case  42 , wherein an end of the adjusting slot  47  is at a center of the case  42  (central end) and the other end is off the center (eccentric end). The weight device  40  is fitted to the axle  12  by passing the connecting portion  14  through the adjusting slot  47 . The second cover  50  is put on the weight device  40 , and a fastener  52  is inserted into the hole on the second cover  50  and screwed into a threaded hole of the connecting portion  14  of the axle  12 . 
         [0026]    The weight device  40  is able to be moved in a radial direction when the fastener  52  is loosed, and the fastener  52  should be fastened again to fix the weight device  40 . When the weight device  40  is moved to a central position, where the connecting portion  14  of the axle  12  is located at the central end of the adjusting slot  47 , the weight device  40  will rotate centrally. When the weight device  40  is moved in the radial direction to have the connecting portion  14  of the axle  12  off the central end, the weight device  40  will rotate eccentrically. When the connecting portion  14  of the axle  12  reaches the eccentric end of the adjusting slot  47 , as shown in  FIG. 5 , the weight device  40  has a maximum eccentric rotation. 
         [0027]    As shown in  FIG. 2 , the weight members  41  are separated into three stacks, and the stacks of the weight members  41  are unevenly distributed in the case  42 . Therefore, there is a region in the case  42  without the weight members  41 , and the adjusting slot  47  extends in the region. Because of the uneven distribution of the weight members  41  in the case  42 , the weight device  40  rotates a little eccentrically when the axle  12  is located at the central end of the adjusting slot  47 . It is obvious that the eccentric end of the adjusting slot  47  is distal to a center of gravity of the weight members  41  that the weight device  40  will have an eccentric rotation when the weight device  40  is moved to the eccentric position. 
         [0028]      FIG. 7  shows the dumbbell  100  of the present invention with the weight devices  40  located at the central positions. The weight devices  40  and the wheels  30  centrally rotate together when user holds the handle  10  and shakes it. In this circumstance, the dumbbell  100  of the present invention is similar to an ordinary dumbbell that user may do the ordinary exercises, such as biceps curls and triceps extensions. 
         [0029]      FIG. 6  shows the weight devices  40  being moved to eccentric positions. The weight devices  40  have eccentric rotations when user shakes the dumbbell  100  of the present invention. In comparison with  FIG. 7 , in which the weight devices  40  rotate centrally, the eccentric rotations of the weight devices  40  will provide an extra loading. 
         [0030]      FIG. 8  shows another training mode of the dumbbell  100  of the present invention, in which the weight devices  40  have to be moved back to the central positions. The dumbbell  100  is put on the ground, and user holds the dumbbell  100  and stands on the ground by feet or knees to roll out and roll in. In this situation, the dumbbell  100  of the present invention functions as a roller (or wheel) for abdominal training. The wheels  30  are the main to serve the rolling function in abdominal training. 
         [0031]    The description above is a few preferred embodiments of the present invention and the equivalence of the present invention is still in the scope of claim construction of the present invention.