Patent Publication Number: US-7588520-B2

Title: Dumbbell weight training device having detachable weight plates

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a versatile dumbbell of the type commonly found in a fitness center to be used as a weight training device. The dumbbell is adapted to carry a set of interchangeable weight plates that are detachably connected to one another so that the gross weight of the dumbbell can be selectively and incrementally varied to fit a weight training program of the user. 
   2. Background Art 
   A dumbbell is a conventional weight training device that has long been used by body builders and others to improve their physical strength and appearance as part of a weight training or exercise program. Such a dumbbell typically includes a cylindrical gripping handle that carries a pair of weight plates at opposite ends thereof. In this regard, the weight plates are fixedly connected to the ends of the gripping handle. Should the user wish to increase the weight to be lifted, he must find an altogether different dumbbell. In other words, there is no way for the user to selectively adjust or progressively change the weight of a dumbbell to be used during a workout, such that the gross weight of each dumbbell remains the same at all times. 
   As a consequence of the foregoing, the fitness center or the user (should he elect to exercise at his home or office) must maintain many different dumbbells having characteristically different gross weights. Accordingly, the cost to acquire a variety of dumbbells and the space consumed as a result thereof are undesirably increased. Moreover, the user&#39;s ability to easily and quickly expand his personal weight training program is hampered by the requirement to have ready access to such different dumbbells. 
   Nevertheless, one commercially available adjustable weight dumbbell system is available by referring to U.S. Pat. No. 5,839,997. This patented dumbbell system is mechanically complicated. Therefore, users may experience confusion which may lead to mistakes when attempting to vary the gross weight of the dumbbell during a workout. In addition, the maximum weight that can be added to the dumbbell system is limited. 
   Hence, what is desirable is a mechanically simple and easy-to-use dumbbell weight training device having a series of interchangeable weight plates with correspondingly different weights that are adapted to be detachably connected to one another so that the gross weight of a single dumbbell may be selectively and progressively varied to conform to the weight training program of the user. 
   SUMMARY OF THE INVENTION 
   In general terms, a versatile dumbbell is disclosed herein of the kind that is typically found in a fitness center to be used as a weight training device. The present improvement advantageously permits a user to quickly and easily vary the gross weight of a single dumbbell by adding or removing different weight plates having correspondingly different characteristic weights. To this end, each weight plate is preferably of uniform size, thickness and (e.g., disc-like) shape. An outer body manufactured from a durable (e.g., urethane) material surrounds a steel core, the size and weight of which determines the overall weight of the weight plate. 
   The dumbbell includes a pair of disc-like collars fixedly connected to opposite ends of a cylindrical gripping handle. One or more weight plates are detachably connected to each collar. Each weight plate has opposing inside and outside faces. A radial coupling slot is formed in the inside face of each weight plate. A cartridge cavity is also formed in the inside face adjacent the coupling slot. An engagement pin receiving channel extends between the coupling slot and the cartridge cavity. A locking cartridge is located within the cartridge cavity at the inside face of the weight plate. The locking cartridge is operable to couple an additional weight plate to an existing weight plate being carried at one end of the gripping handle. A radial coupling body projects outwardly from the outside face of each weight plate. An engagement pin extension channel runs laterally through the coupling body. The coupling body at the outside face of an existing weight plate is sized and shaped for receipt within the coupling slot at the inside face of an additional weight plate such that the additional and existing weight plates are aligned face to face one another. 
   The locking cartridge received within the cartridge cavity of the additional weight plate includes an engagement pin and a control knob connected to one end of the engagement pin and accessible at the periphery of the weight plate. A pushing force applied in a first direction to the control knob causes the engagement pin to move through the locking cartridge of the additional weight plate from a retracted position to an extended position. In the extended position, the engagement pin rides through the engagement pin receiving channel and into the engagement pin extension channel that is formed in the coupling body of the existing weight plate. The receipt of the engagement pin within the engagement pin extension channel prevents a separation of the coupling body of the existing weight plate from the coupling slot of the additional weight plate, whereby the additional weight plate is detachably connected and locked to the existing weight plate. 
   A pushing force applied in an opposite direction to the control knob causes the engagement pin of the locking cartridge of the additional weight plate to move from the extended position to the retracted position so as to ride out of the engagement pin extension channel in the coupling body of the existing weight plate. Accordingly, the coupling body of the existing weight plate can now be separated from the coupling slot of the additional weight plate, whereby the additional weight plate is disconnected from the existing weight plate. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view illustrating an easy to use, adjustable weight dumbbell according to a preferred embodiment of this invention having a series of interchangeable weight plates adapted to be detachably connected to one another in face-to-face alignment at opposite ends of a gripping handle; 
       FIG. 2  shows the inside face of each weight plate of the adjustable weight dumbbell of  FIG. 1 ; 
       FIG. 3  shows the outside face of each weight plate of the adjustable weight dumbbell of  FIG. 1 ; 
       FIG. 4  shows a locking cartridge that is operable for coupling an additional weight plate to an existing weight plate and having an engagement pin moved to a retracted position; 
       FIG. 5  shows the locking cartridge of  FIG. 4  with the engagement pin thereof moved to an extended position; 
       FIG. 6  shows the locking cartridge of  FIG. 4  having the engagement pin thereof in the retracted position and being received within a cartridge cavity formed at the inside face of a first weight plate; 
       FIG. 7  shows the locking cartridge of  FIG. 4  having the engagement pin thereof in the retracted position and being received within the cartridge cavity of another weight plate to be detachably connected to the weight plate of  FIG. 6 ; 
       FIG. 8  shows the weight plate of  FIG. 6  with the engagement pin of the locking cartridge thereof moved to the extended position; and 
       FIG. 9  shows the dumbbell of  FIG. 1  with all of the weight plates removed therefrom. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1  of the drawings, there is shown a versatile dumbbell  1  of the type to be used as a personal exercise and weight training device. Thus, the dumbbell  1  will be typically found at a fitness center or at home to be repeatedly lifted by one seeking to improve his physical appearance, strength and conditioning. Although it is contemplated that the dumbbell  1  shown in  FIG. 1  will be grasped in a single hand of a user, the teachings of this invention are also applicable to a larger bar bell device of the type to be grasped and lifted with both hands of the user. 
   The dumbbell  1  has a cylindrical handle  3  that extends between and is fixedly connected to opposing collars  5  and  7  (best shown in  FIG. 9 ). The handle  3  is sized to be gripped within a single hand of a user. In the event that the teachings of this invention are applied to a bar bell, the length of handle  3  is extended to accommodate both hands of the user. As will be explained in greater detail hereinafter, a variable number of weight plates  8  and  10  can be detachably connected to each other and to respective ones of the collars  5  and  7  at opposite ends of the gripping handle  3 . Ideally, a total of four weight plates  8  and  10  will be detachably connected to each collar  5  and  7 . However, any suitable number of weight plates can be carried by the dumbbell  1 . By virtue of being able to vary the number of weight plates  8  and  10  to be carried by dumbbell  1 , the gross weight of the dumbbell can be selectively and incrementally changed so as to be tailored to conform to the weight training program of the user. 
   Details of the weight plates  8  and  10  to be detachably connected to each other and to the collars  5  and  7  at opposite ends of gripping bar  3  are initially described while referring to  FIGS. 2  and  3  of the drawings. Each weight plate (e.g.,  8 ) preferably has an identical size, thickness and (e.g., disc-like) shape. Each weight plate  8  also preferably has a solid steel core (not shown) that is surrounded by an outer casing  11  manufactured from a durable, impact-resistant (e.g., urethane) material. The precise weight of the weight plate  8  will depend upon the corresponding size and weight of its steel core. In this regard, it is contemplated that a series of weight plates will be available at 2½ pound increments. Such a series of weight plates can be conveniently stored on a dumbbell rack to enable the user to pick and choose among particular ones of the weight plates to be detachably connected to each other and to the collars  5  and  7  (of  FIG. 1 ) so that a dumbbell can be quickly and easily assembled to meet the weight training needs of the user. By virtue of the foregoing, the user will not be required to accumulate a variety of expensive and space-consuming dumbbells for each of the different weight combinations available by coupling different ones of the individual weight plates  8  and  10  of the dumbbell  1  of this invention. 
   Each weight plate  8  includes opposing inside and outside faces. As is best shown in  FIG. 2 , a radial coupling slot  12  is formed (e.g., molded) in the outer casing  11  at the inside face of weight plate  8 . A cartridge cavity  14  is also formed (e.g., molded) in casing  11  at the inside face of weight plate  8  to lie adjacent coupling slot  12 . A relatively narrow engagement pin receiving channel  16  extends between the cartridge cavity  14  and the coupling slot  12 . As is best shown in  FIG. 3 , a radial coupling body  18  projects outwardly from casing  11  at the outside face of weight plate  8 . An engagement pin extension channel  20  is formed in and runs laterally across coupling body  18 . 
   As will soon be described, the radial coupling body  18  projecting from the outside face of a first weight plate (e.g., designated  8 - 1  in  FIG. 1 ) is sized and shaped to be received within an oppositely aligned radial coupling slot  12  that is formed at the inside face of an adjacent weight plate (e.g., designated  8 - 2  in  FIG. 1 ). Moreover, a removable locking cartridge (designated  24  in  FIGS. 4 and 5 ) is sized and shaped to be received by the cartridge cavity  14  formed at the inside face of each weight plate  8 . 
   A description of the aforementioned removable locking cartridge  24  and the receipt of cartridge  24  within cartridge cavity  14  is now provided while referring concurrently to  FIGS. 4-7  of the drawings. The locking cartridge  24  may be the same as that described in my co-pending patent application Ser. No. 11/349,101 filed Feb. 8, 2007, the teachings of which are incorporated herein by reference. Therefore, and for purposes of efficiency, only a brief description of the operation of locking cartridge  24  will be provided. The removable locking cartridge  24  carried by each detachable weight plate  8  of the dumbbell  1  (of  FIG. 1 ) includes a lock body  26 . A longitudinal guide slot  28  extends through the lock body  26  of locking cartridge  24 . One end of an engagement pin  30  projects outwardly from the guide slot  28  at the bottom of cartridge  24 . A manually-accessible control knob  32  is attached to the opposite end of engagement pin  32  at the top of locking cartridge  24  along the periphery (i.e., circumference) of weight plate  8 . 
   The control knob  32  is adapted to slide back and forth over the guide slot  28  through the lock body  26  of locking cartridge  24  to cause the engagement pin  30  to move between a retracted position (of  FIG. 4 ) and an extended position (of  FIG. 5 ). As previously disclosed, the locking cartridge  24  is removably received within the cartridge cavity  14  of each weight plate  8  (e.g., designated  8 - 3  and  8 - 2 ) in  FIGS. 6 and 7 . With locking cartridge  24  located in cavity  14 , the engagement pin  30  thereof is aligned to slide through the engagement pin receiving channel  16  extending between the cartridge cavity  14  and the coupling slot  12  at the inside face of each weight plate  8 - 3 . The engagement pin  30  will slide reciprocally through the engagement pin receiving channel  16  from its retracted position (as shown in  FIG. 4 ) to its extended position (as shown in  FIG. 5 ) in response to a pushing force applied by the user to the control knob  32  by which to cause the control knob to slide along the guide slot  28  through lock body  26 . 
   When it is desirable to add more weight to the dumbbell  1  of  FIG. 1 , one or more additional weight plates ( 8 - 3  and  10 - 3 ) are detachably connected to respective existing weight plates  8 - 2  and  10 - 2  being carried at each end of the gripping handle  3 . By way of specific example, and referring once again to  FIG. 1 , the additional weight plate  8 - 3  (of  FIG. 6 ) is coupled to an adjacent existing weight plate  8 - 2  (of  FIG. 7 ). To accomplish the foregoing, the additional weight plate  8 - 3  is moved into face-to-face alignment against existing weight plate  8 - 2 , such that the radial coupling body  18  projecting from the outside face of weight plate  8 - 2  is received within the radial coupling slot  12  that is formed in the inside face of weight plate  8 - 3 . 
   Next, the user applies a pushing force to the control knob  32  of the locking cartridge  24  of the additional weight plate  8 - 3 . The pushing force causes the control knob  32  to slide along the guide slot  28  (in the direction of reference arrow  34 ) of locking cartridge  24  by which to cause the engagement pin  30  to move from its retracted position (of  FIG. 4 ) to its extended position (of  FIG. 5 ). That is to say, the engagement pin  30  will travel through the engagement pin receiving channel  16  and into the coupling slot  12  of the weight plate  8 - 3  at which to engage the adjacent weight plate  8 - 2  at the axially-aligned engagement pin extension channel  20  that runs laterally through the coupling body  18  of weight plate  8 - 2 .  FIG. 8  of the drawings shows the additional weight plate  8 - 3  separated from its adjacent weight plate  8 - 2  of  FIG. 1 , but with the control knob  32  of locking cartridge  24  moved along guide slot  28  to cause the engagement pin  30  to move to the extended position across coupling slot  12  at which to engage weight plate  8 - 2  at the coupling body  18  projecting therefrom. 
   With the engagement pin  30  of the locking cartridge  24  moved to the extended position and located within the engagement pin extension channel  20  as just explained, the additional weight plate  8 - 3  will be detachably connected and locked to its adjacent existing weight plate  8 - 2  of dumbbell  1 . The receipt of engagement pin  30  of weight plate  8 - 3  within the engagement pin extension channel  20  of weight plate  8 - 2  prevents an inadvertent separation of the coupling body  18  of weight plate  8 - 2  from the coupling slot  12  of weight plate  8 - 3 . By detachably connecting the additional weight plate  8 - 3  to the existing weight plate  8 - 2 , the user is able to selectively and incrementally increase the gross weight of the dumbbell  1 . 
   Should it be desirable to remove weight plate  8 - 3  or disassemble the dumbbell  1 , the control knob  30  of locking cartridge  24  is pushed in a direction opposite to that represented by the reference arrow  34  of  FIG. 1 . The engagement pin  30  of the locking cartridge  24  of weight plate  8 - 3  is correspondingly moved to the retracted position of  FIG. 4 . Accordingly, the engagement pin  30  is withdrawn from the engagement pin extension channel  20  in the coupling body  18  of existing weight plate  8 - 2  to enable the coupling body  18  to be removed from the coupling slot  12  of weight plate  8 - 3  whereby weight plate  8 - 3  can now be disconnected from weight plate  8 - 2 . The disconnected weight plate  8 - 3  may be returned to a weight plate rack, and a different weight plate having a correspondingly different weight may be substituted therefor and detachably connected to the existing weight plate  8 - 2  in an identical manner to that just described with respect to weight plate  8 - 3 . 
     FIG. 9  of the drawings shows the dumbbell  1  of  FIG. 1  with all of the weight plates removed. In this case, only the opposing collars  5  and  7  and the handle  3  extending therebetween remain during periods of non-use. It will then be up to a user to add one or more weight plates (e.g.,  8 - 1  and  10 - 2 ) as needed to respective collars  5  and  7  in the same manner that an additional and an existing weight plate are coupled to one another. Therefore, each collar  5  and  7  includes a radial coupling body  38  projecting from an outside face and having an engagement pin extension channel  40  running laterally thereacross. 
   In the assembled, ready-to-use dumbbell configuration of  FIG. 1 , the radial coupling body  38  from one collar (e.g.,  5 ) is suitably sized and shaped to be received within the radial coupling slot  12  formed at the inside face of an adjacent weight plate (e.g.,  8 - 1 ). The engagement pin extension channel  40  of coupling body  38  is correspondingly aligned to receive an engagement pin (designed  30  in  FIGS. 4 and 5 ) from the locking cartridge  24  of weight plate  8 - 1 , whereby the weight plate  8 - 1  will be detachably connected to the collar  5 .