Patent Publication Number: US-8529415-B2

Title: Dumbbell

Description:
BACKGROUND AND SUMMARY 
     The present invention relates to a dumbbell with a selectable number of weight disks and comprises a base assembly, in which a first and second set of separate weight disks standing upright are insertable, the weight disks having openings which lie in alignment with one another when the weight disks stand in the base assembly, a handle with pin members axially projectable in opposing directions for insertion in the openings of the weight disks, the projection lengths of the pin members from the handle being selectable in order thereby to permit a selection of the number of weight disks accommodated on the handle, and neighbouring weight disks and the handle having mutually cooperating connecting means which are disposed, in the axial direction of the dumbbell, to interconnect neighbouring weight disks with one another and the handle, but, in a radial direction, to permit separation of one weight disk from a neighbouring weight disk and the handle, respectively. 
     WO 2007/123461 discloses a dumbbell which has a base unit with a handle insertable therein, the base unit having accommodation spaces for a first and second set of weight disks. The handle has pins projectable in opposing directions, which may be accommodated in central openings in the weight disks when they stand upright in the base unit. 
     For fixedly retaining the weight disks accommodated by the pins, the pins display, in their free ends, locking means which prevent the outermost weight disks on the pins, and thereby all weight disks located inside them, from falling off in the axial direction. 
     A dumbbell of this design and construction enjoys many advantages, above all in that it is extremely convenient to use, but is has proved to be somewhat fragile in terms of 
     pure mechanical strength. In addition, it comprises a large number of small parts, for which reason manufacturing costs are relatively high. 
     U.S. Pat. No. 6,416,446 also discloses a dumbbell which has a base assembly with two sets of weight plates and a handle located therebetween. The handle has rods axially extendable in opposing directions which are disposed to extend through openings in the weight plates of the dumbbell. 
     The weight plates according to this US patent Specification have connecting means which, in the axial direction, interconnect neighbouring weight plates but which permit separation of two adjacent weight plates in a radial direction, in practice up out of the base assembly when the dumbbell is lifted. The number of lifted weight plates is defined by the extent of the rods extendable in opposing directions outside both end surfaces of the handle. 
     This design and construction is complex, with gears for extending the rods, the handle having a U-shaped stirrup portion. In addition, in certain embodiments, the weight plates are interconnected pairwise via rods which are parallel with the gripping member of the handle. Both the stirrup portion and its rods can be dangerous to the wrist of the user if the handle were to be rotated in the grip of the hand. 
     U.S. Pat. No. 6,228,003 discloses a dumbbell which also has a handle with rods projectable in opposing directions for interconnecting the handle with an optionally selectable number of weight plates. In this construction, the weight plates or disks are united pairwise by the intermediary of rods, which are impractical on use of the dumbbell and which may constitute a risk element. 
     It is desirable to further develop the dumbbell intimated by way of introduction in such a manner that the drawbacks in the prior art technology are obviated. Above all, it is desirable to realise a dumbbell which is safe to use, which offers reliable fixing of the selected number of weight disks on the handle and which in addition is simple and economical in manufacture. 
     According to an aspect of the present invention, a dumbbell intimated by way of introduction is characterised in that the handle has locking means for locking the pin members in selected projection positions on lifting of the dumbbell out of the base assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       The present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawings. In the accompanying Drawings: 
         FIG. 1  is a perspective view of a base assembly in which is placed a handle included in a dumbbell and a set of weight disks which stand upright in the base assembly; 
         FIG. 2  shows the handle of  FIG. 1 , seen obliquely from beneath together with weight disks disposed on the handle; 
         FIG. 3  shows the base assembly of  FIG. 1  in the partly cut-away state and without handle and weight disks; 
         FIG. 4  shows in the partly cut-away state the base assembly of  FIG. 1  with a handle disposed therein and a set of weight disks; 
         FIG. 5  shows two different perspective views of a weight disk; 
         FIG. 6  shows a weight disk according to  FIG. 5  in the partly cut-away state; 
         FIG. 7  is an exploded view showing a base assembly and a number of weight disks which are placed therein; and 
         FIG. 8  is an exploded view of a handle, however in a slightly modified version, the distal side in  FIG. 8  being turned to face downwards in accordance with the arrow A when the handle lies in the base assembly. 
     
    
    
     DETAILED DESCRIPTION 
     In purely general terms, the dumbbell according to the present invention belongs to that category of dumbbell which has a selectable number of weight disks  1  which are fixable on a handle  2  and which are intended, standing upright, to be accommodated in corresponding accommodation spaces  3  in a base assembly  4 . The dumbbell is designed in such a manner that it is possible to lift up from the base assembly the handle with a selectable number of weight disks fixed on the handle. 
     It will further be apparent from  FIG. 1  that the handle  2  displays, at its opposing ends, housings  5  from which pin members  6  are disposed to be projectable in opposing directions in the longitudinal direction of the handle  2  and which are movable along the longitudinal centre axis of the handle. While not being apparent from  FIG. 1  (see instead  FIGS. 5 ,  6  and  7 ), the weight disks  1  have central openings  14  into which the pin members  6  are insertable. The purpose of the pin members is, by direct contact, abutment, to cooperate with and support the weight disks  1  when a dumbbell is lifted up out of the base assembly. In addition, the outer end sides of the housings  5  facing away from one another display connecting means  7  which are disposed for cooperation with corresponding connecting means  8  on the weight disks. 
     As is intimated in  FIG. 1 , the pin members  6  are suitably designed as solid rods of superior mechanical strength. Possibly, a tubular design may also come into consideration, in which event there may be accommodated interiorly in the pin members parts that are not described here. The free ends of the pin members are smooth, possibly slightly bevelled, and in this position lack transversely directed projecting parts such as, for example, flip-out locking devices so as to facilitate entry into the weight disks. 
     The connecting means are designed in such a manner that, in the axial direction, i.e. along a longitudinal centre axis to the handle, they interconnect neighbouring weight disks at the same time as they permit a radial displacement of one weight disk in relation to another (in  FIG. 1  in the vertical direction, provided that the base assembly  4  rests on a horizontal substrate). The innermost weight disks are correspondingly interconnected to the connecting means  7  of the housings  5 . 
     It follows from the foregoing that the number of weight disks which, in their central openings  14 , have the pin members  6 , can no longer carry out the radial movements, for which reason on lifting of the handle  2  out of the base assembly  4 , this number of weight disks will accompany the handle up out of the base assembly. 
     The number of weight disks which is located outside the raised weight disks, and into whose central openings  14  the pin members  6  do not extend, is therefore not affected by the projecting pin members  6 , for which reason these outer weight disks will remain in place in the base assembly  4 . 
     In order to realise the above-considered axial projection of the pin members  6 , there is disposed in the handle a screw mechanism which realises the axial projection or retraction of the pin members  6  when a rotary section  9  between the housings  5  of the handle is turned in relation to the housings about the longitudinal centre axis of the handle. 
     In order to define and/or display such projection lengths for the pin members  6  as correspond to a complete number of weight disks, the handle  2  of the dumbbell includes one or more indexing devices which will be described in greater detail hereinbelow. The purpose of the indexing device is thus to facilitate a gradual projection of the pin members  6  by correct step lengths. 
     It will be apparent from  FIG. 8  that the handle has an inner tube  40  with two longitudinal apertures  41 . The pin members  6  which, in this embodiment, are solid metal rods, are longitudinally displaceable interiorly in the inner tube  40  and have pins  42  which extend out through the apertures, whereby the pin members  6  are prevented from rotating in relation to the inner tube  40 . Outside the inner tube  40 , there is provided an outer tube  43  with two helical grooves, in which the pins  42  are accommodated. The above-described design and construction implies that when relative rotation takes place between the inner  40  and the outer  43  tubes, the pin members  6  will move axially in the longitudinal direction. 
     Outside the outer tube  43 , there is disposed a rotary portion  9  which the user of the dumbbell manually twists when a choice is made of the number of weight disks  1  on the dumbbell. 
     The rotary portion  9  is rotationally interconnected with an index ring  45 , which is included in the above-discussed indexing device and which displays, along its periphery, markings  46  for the number of weight disks to be accommodated on the dumbbell. The markings  46  are shown in an opening  47  in the outer casing  48  of the housings  5 , the outer casing being positionally fixed in the direction of rotation when the dumbbell rests in the base assembly  4  and, moreover, the outer casing is rotationally interconnected with the inner tube  40 . 
     It will be apparent from  FIG. 3 , which shows an embodiment modified in relation to that of  FIG. 8 , that the base assembly  4  has two seats  10  for accommodating and positionally fixing the housings  5  of the handle  2 , in particular its outer casing  48 . In addition, the base assembly  4  has, at its opposing ends, accommodation spaces  3  each for accommodating a set of weight disks  1 . Furthermore, the end walls  11  of the base assembly  4  are provided with connecting means  12  for cooperation with the corresponding connecting means  8  on both of the outermost of the weight disks standing upright in the base assembly. Hereby, the weight disks will be positioned in the direction of rotation in relation to the base assembly  4 . 
     The housings  5  and the seats  10  have mutually cooperating positioning means  38 ,  39  by means of which the handle  2  (apart from its gripping portion  9 ) is positioned in the direction of rotation about the longitudinal centre axis of the handle in relation to the base assembly when the handle is in position in the base assembly. This position of rotation defined in relation to the base assembly also implies that the connecting means  7  of the housings  5  are located in the correct position in relation to the connecting means of the weight disks when the weight disks stand upright in the base assembly, since the connecting means  8  of the outermost weight disks cooperate with the connecting means  12  on the end walls  11  of the base assembly. The positioning means are in the form of grooves  38  in the housings  5 , and projections  39  in the seats  10  insertable in the grooves. 
     According to the present invention, it is possible to dispense with the positioning means  38  and  39 , since the handle  2  of the assembly and the weight disks  1  are also aligned in the direction of rotation about the longitudinal centre axis of the dumbbell by cooperation between the connecting means  8  of the weight disks  1  and the connecting means  12  of the base assembly  4 , or alternatively between corresponding connecting means on the weight disks. 
     It will be apparent from  FIGS. 5 and 6  taken together that the weight disks are substantially circular, planar disks with central openings  14  for accommodating the pin members  6  on the handle  2 . Furthermore, the weight disks  1  have substantially circular peripheral edges, which are unbroken and which extend throughout the entire periphery of the whole of the weight disk. Otherwise expressed, the central openings  14  have no communication whatever with the peripheral edges of the weight disks in the form of grooves, recesses or the like. 
     It will be further apparent from  FIGS. 5 and 6  that the connecting means  8  of the weight disks  1  include a depression  16  on the one side of the weight disk and a corresponding projection  17  on the opposing side of the weight disk. Preferably, the projections  17  and the recesses  16  are complementary to one another, although this is not absolutely critically necessary. Both the projections and the recesses have a longitudinal centre line, which is also a diameter line for the weight disk through the central opening  14 . In the longitudinal direction of this centre line, both the depressions  16  and the projections  17  are cuneiform, symmetrically about the longitudinal centre line. Further, the cross-sectional configuration in the depressions  16  is undercut, for example dovetailed, the projections  17  having a corresponding profile. This implies that when two weight disks are interconnected with the projection  17  on the one weight disk accommodated in the depression  16  on the other weight disk, the weight disks can no longer be displaced in the axial direction in relation to one another. On the other hand, they are displaceable only in one direction along the above-mentioned longitudinal centre line to the projection  17  and the depression  16 . This longitudinal centre line is vertical when the weight disks are in position upright in the base assembly  4  (see  FIG. 1 ) and in the direction of rotation are aligned by cooperation between the projections  17  of the outermost weight disk and the connecting means of the base assembly  4 . 
     It will be apparent from  FIGS. 1 and 7  that when the weight disks  1  are standing in the base assembly  4  or are just about to lifted up out of or deposited down into the base assembly, the widest ends of the projections  17  and recesses or depressions  16  are turned to face upwards, for which reason an inner weight disk  1  (located more proximal the handle  2 ) can always be lowered down into or lifted up out of an outer weight disk, as long as the pin members  6  do not extend through the central openings  14  in both of these weight disks. 
     It will be apparent from  FIG. 2  that the housings  5  have a corresponding design of their connecting means  7 , viz. projections  18 , which may be said to correspond to a part of the projection  17  on a weight disk and which therefore fit into the depressions  16  on both of the innermost weight disks  1 . 
     It will be apparent from  FIG. 5  that the projection  17  on the weight disk has, in its narrower end, a change bevel  19  whose purpose is to facilitate insertion of the projection  17  in a corresponding depression  16  on an adjacent weight disk. It will further be apparent that the depression  16  is open all the way out to the peripheral edge of the weight disk so that the projection on an adjacent weight disk can thereby readily be passed down in the wider end  20  of a depression  16 . 
     As was considered above, both of the pin members  6  are projectable in opposing axial directions from the handle  2  by rotation of the rotary portion  9  of the handle in relation to the housings  5  of the handle which, in the direction of rotation, is positionally fixed in the base assembly  4  via the projections  18  of the housings  5  and the depressions  16  and projections  17  of the weight disks  1 , the projection  17  of the outermost weight disk being accommodated in the connecting means  12  of the base assembly  4 . Since this axial projection takes place with the aid of a screw mechanism, the projection will be continuous as a function of the angle of rotation of the rotary portion  9 . It will readily be perceived that only certain projection lengths of the pin members are desirable, namely such projection lengths as imply that the end surfaces  21  of the pin members  6  are located immediately inside an outer side of a weight disk  1  standing upright in the base assembly. Setting of such projection lengths is made possible or facilitated by the above mentioned indexing devices. With such a projection length, all weight disks inside the relevant weight disk in the radial direction will have complete support from the pin member  6  and the outermost weight disk has as good support as it is possible to achieve. On the other hand, the weight disk lying outside is wholly unaffected by the pin member  6 . 
     In order to ensure that, on using a raised dumbbell, no relative rotation takes place between the rotary portion  9  and the weight disks connected to the housings  5 , for example because of the flywheel effect of the weight disks, which might possibly entail that the pin members  6  are retracted to some extent, so that at least the outermost weight disks are free and will fall off the dumbbell, both of the housings  5  have locking means which, in selected projection lengths, lock the pin members in the axial direction as soon as the dumbbell is lifted out of the base assembly  4 . To this end, both of the pin members  6  have a first series of recesses  22  ( FIGS. 1 and 4 ), where the distance between adjacent recesses corresponds to the thickness of one weight disk  1 . Interiorly in both of the housings  5 , there are provided, as will be apparent from  FIGS. 4 and 8 , sliding portions  23  with openings through which the pin members  6  extend. The sliding portions  23  are spring-biased by means of springs  24  in a downward direction when the dumbbell rests in the base assembly  4 . In such instance, the sliding portions  23  have edges which, under the action of the springs  24 , strive to snap down into one of the recesses  22  so that, as a result, the pin members are locked in the axial direction as a result of the engagement between the recesses  22  and the sliding portions  23 . 
     In order to permit outward pivoting of both of the pin members  6  when the dumbbell rests in the base assembly  4 , blocking means are provided which block the locking function of the locking means, but which cease to function as soon as the dumbbell is lifted out of the base assembly  4 . The blocking means are in the form of upstanding heels  25  which are disposed on the seats  10  in the base assembly  4 . The heels  25  are disposed to extend in through openings  26  in the lower sides of the housings  5  when the housings rest in the seats  10  ( FIG. 2 ). When the heels  25  in this manner extend in to the interior of the housings, they come into contact with lower end portions  27  on the above-mentioned sliding portions  23  so that these are lifted a sufficient distance against the action of the springs  24  to become disengaged from the recesses  22  of the pin members  6 . 
     In the foregoing, it was mentioned that the projection of both of the pin members in the axial direction takes place in a continuous movement by rotation of the rotary portion  9  of the handle in relation to the housings  5 . In order to obtain stepwise projection lengths of the pin members which correspond to the locking positions for the locking means and where, as was mentioned above, the end surfaces of the pin members are located immediately inside the outer sides of the relevant weight disks, the present invention includes, as was mentioned above, an indexing device which gives stepwise setting possibilities in the longitudinal direction of the pin members  6 . This indexing device comprises a second series of recesses  28  on the pin members  6 , where the distance between adjacent recesses in the first and the second series mutually corresponds and corresponds to the thickness of one weight disk. The recesses  28  in the second series have V-shaped or circular cross section in order to avoid an excessively powerful locking function. Interiorly in each one of the housings  5 , there is further provided a snap portion  29  ( FIG. 4 ) which, under the action of a spring (not shown in this Figure), is movable into engagement with one of the recesses  28 . In such instance, the design and formation of the end of the snap portion  29  facing towards the pin members and the formation of the recesses  28  are such that an accurate stepwise projection of the pin members can take place without the resistance being excessively great on “unscrewing” of the pin members. 
     The snap portions  29  fulfill a further function, namely that of preventing lifting of the handle  2  out of the base assembly  4  when the pin members  6  are located in “incorrect” positions. It will be apparent from  FIG. 2  that the housings  5  have openings  36  through which the snap portions  29  can extend out when the inner end regions of the snap portions are located in abutment against the pin members  6  between two of their recesses  28 . When the snap portions  29  by such means extend outside the peripheries of the housings  5 , their projecting portions will be accommodated in corresponding recesses  37  in the seats  10  of the base assembly  4  in order thereby to prevent lifting of the handle  2  out of the base assembly with incorrect projection lengths of the pin members  6 . 
       FIG. 8  shows a slightly modified embodiment, where the one series of recesses  28 , the snap portion  29 , the opening  36  as well as the recess  37  are omitted. The correct projection length for the pin members  6  is realised in this embodiment in that there are disposed recesses  49  along the peripheries of the index rings  45  at equal spacing in the circumferential direction. On the seats, catch-shaped projections  50  are provided which, through openings from beneath, extend into the housings  5  when the dumbbell rests in the base assembly  4 . The projections have shanks which are substantially parallel with the centre axis of the handle  2  and which grasp interiorly about the peripheral edge of the index rings  45 . When these projections are located between the recesses  49  of the index rings  45 , they prevent a lifting of the dumbbell up out of the base assembly  4 . 
     When, on the other hand, the projections  50  are located in register with any of the recesses  49 , lifting may take place. In such positions, the index ring  45 , and thereby the gripping portion  9  and the outer tube  43  are in such positions of rotation that the outer end surfaces  21  of the pin members  6  are located immediately inside the outsides of two weight disks  1 . That number of weight disks which is thus carried by the pin members  6  is displayed as a corresponding marking  46  in the opening  47  of the housing  5 . 
     As is apparent from  FIGS. 5 and 6 , the weight disks are separate units which, apart from the connecting means  7  and  8 , are not interconnected via any struts or rods, which is a common prior art practice when such struts or rods are used for pairwise interconnection of two weight disks, one at each end of the dumbbell. This implies that, according to the present invention, the space through 360° about the handle  2  is completely free throughout the entire length of the handle in principle between the connecting means  7  of the housings  5 . This is a crucial feature in the subject matter of the present invention, since such connection struts or rods could hit and injure the wrist of a user if the dumbbell, because of its considerable flywheel effect, were to twist or pivot in the grip of the user. 
     According to the present invention, both of the pin members  6  are disposed coaxially, with a longitudinal centre line to the handle  2  and coaxially in relation to the circumferential surfaces of both of the housings  5 . Since the openings  14  of the weight disks  1  are disposed coaxially with the peripheral edges  15  of the weight disks, the dumbbell, as thus far described, will be rotationally symmetrical as regards the position of the point of gravity. 
     It will be apparent from  FIGS. 5 and 6 , primarily  FIG. 6 , that each weight disk has a core  30  of a relatively heavy, first material and an outer layer  31  surrounding the core, of a second material. The core  30  comprises a substantially planar, relatively thin and circular disk  32  of metal, preferably steel, which has a central opening  33  which is coaxial with the central opening  14  of the weight disk and which may appropriately be slightly larger than it. On that side of the disk  32  where the depression  16  of the disk is disposed, there are secured substantially circle-segment shaped weight portions  34 , which are of considerably greater thickness than the disk  32 . In the radial direction, the weight portions  34  extend in to the immediate proximity of the longitudinal, slanting edges  35  which, on both sides, define the depression  16  of the weight disk. The relatively slight cuneiform configuration which the depressions  16  and the projections  17  have on the weight disk entails that the total point of gravity of the weight disk will but insignificantly deviate from the centre of the through-going opening  14 . Further, the edges of the weight portions  34  facing towards the depressions  16  have a supporting effect against the opposing edges  35  of the depression. 
     The outer layer  31  of the weight disk is suitably manufactured by injection moulding of plastic around the core  30 . This implies that the projections  17  of the weight disks also consist of or comprises plastic. Further, the central opening  14  is surrounded by a plastic layer.