DESCRIPTION OF THE DRAWING
FIG. 1 is a front elevation view showing one end of a dumbbell incorporating the invention herein;
FIG. 2 is a left side elevation view of the dumbbell of FIG. 1;
FIG. 3 is a front elevation view of the dumbbell illustrated in FIG. 1 with an added, magnetically responsive weight plate 20 being slid onto its outer shaft 14 in accordance with the invention;
FIG. 4 is a front elevation view of the dumbbell of FIG. 1 with the magnetically-responsive weight plate fully mounted;
FIG. 5 is a right side elevation view of the magnetically-responsive weight plate shown in FIG. 4;
FIG. 6 is a front elevation view of the dumbbell of FIG. 1 with the magnetically-responsive weight plate fully mounted;
FIG. 7 is a left side elevation view of the dumbbell of FIG. 6;
FIG. 8 is a front elevation view of a dumbbell incorporating a second embodiment of the invention;
FIG. 9 is a front elevation view of the dumbbell of FIG. 8, showing the magnetically-responsive weight plate positioned for mounting onto the dumbbell in accordance with the invention;
FIG. 10 is a right side elevation view of the sleeve 40 of FIG. 8;
FIG. 11 is a left side elevation view of the right magnetically-responsive weight plate 34 illustrated in FIG. 9;
FIG. 12 is a front elevation view of a dumbbell constructed in accordance with a third embodiment of the invention;
FIG. 13 is a left side elevation view of the dumbbell of FIG. 12; and
FIG. 14 is a rear elevation view in schematic of a cabled exercise device constructed in accordance with a fourth embodiment of the invention
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a front elevation view showing one end of a “fixed weight” type dumbbell 10 incorporating the invention herein. Although the invention is discussed in the context of a dumbbell, it should be recognized that bar bells are within the scope of the invention and the term “dumbbell” will be used to denote devices.
The barbell 10 has two generally annular weight plates 12 respectively mounted at opposing ends of a longitudinally-extending shaft 14 in the convention manner. In practice, a plurality of weight plates may be mounted at each end to achieve the desired weight, or a single weight plate may be utilized. The end portion of the shaft 14 extends through and beyond the outermost weight plate.
FIG. 2 is a left side elevation view of the dumbbell of FIG. 1. A pair of magnets 16, 18 are embedded in the outermost weight plate surface at both ends of the dumbbell. The magnets are preferably of the rare earth type, such as neodymium magnets. These are very strong magnets that can be relied upon to securely bind a magnetically-responsive incremental weight plate to the dumbbell. While two magnets 16, 18 are shown in diametrically opposite positions, any other number of magnets could be used, and other positions could be utilized without departing from the scope of the invention.
As illustrated in FIG. 2, one of the magnets 16 has its north pole facing outward, while the other magnet 18 has its south pole facing outward. The dumbbell illustrated in FIGS. 1 and 2 has a “base weight” to which an incremental weight of desired poundage is to be added. FIG. 3 is a front elevation view of the dumbbell of FIG. 1, but showing an outer weight plate 20 of incremental poundage mounted onto the outwardly extending portion of the shaft 14. The weight plate 20 conveniently includes an integrally formed knurled portion 22 of relatively larger diameter that provides a graspable periphery preferably sized to be encompassed by the human hand so that the weight plate 20 can be rotated with one hand in the manner of a jar-top.
FIG. 4 is a left side elevation view of the incremental weight plate 20 shown in FIG. 3. The plate 20 is annular, so as to fit concentrically about the shaft 14. The incremental weight is thereby balanced with respect to the shaft, as is preferably for most lifting movements. Naturally, other shaped plates or non-concentric mountings can be provided if a unbalanced arrangement is desired. As further illustrated in FIG. 4, indicia can be stamped, molded or otherwise placed upon the incremental weight plate to display its added incrementally poundage.
The incremental weight plate 20 becomes magnetically coupled to the weight when it is mounted onto the shaft 14, thereby becoming securely mounted on the dumbbell without the need for a collar. For safety reasons, it is desirable to provide a firm degree of magnetic coupling so that the plate do not disengage during exercise movements. Accordingly, the increment plates can be difficult to remove when one wishes to do so. In accordance with the invention, a decoupling feature is therefore preferably included that aids the user in removing the incremental plate from the dumbbell.
Turning to FIG. 5, a right side elevation view of the incremental weight plate 20 is shown. This is the inwardly-facing surface of the incremental weight plate 20; i.e., the surface that faces and engages the weight plate 12. As shown in FIG. 5, a pair of magnets 24, 26 are embedded in the incremental weight plate and are positioned to overlie the magnets 16, 18 when the incremental weight plate is mounted onto the shaft 14. The magnet 24 has its north pole facing the weight plate 12, while the magnet 22 has its south pole facing the weight plate 12.
The magnets 24, 26 that have been successfully used are 0.5 inches in diameter and 0.5 inches in length, with a tolerance of 0.005 inches. They are slip-fit into respective bore holes in the incremental weight plate, and the top of the bore walls are center punched radially inward around their peripheries to entrap the magnets within the bores.
When the incremental weight plate is mounted onto the shaft 14, it is positioned so that the south pole of magnet 22 overlies the north pole of magnet 16, while the north pole of magnet 24 overlies the south pole of magnet 18, thereby magnetically coupling the incremental weight plate 22 and the weight plate 12 with a sufficient level of forced that securely bonds the two weight plates together.
When the user wishes to decouple the incremental weight plate from the dumbbell, the user merely grips the outer knurled periphery of the incremental weight plate with one hand, in the manner by which a jar top is gripped, while the dumbbell is held by the other hand. The incremental weight plate is then rotated about the shaft 14 by approximately 180° until the north poles of magnets 16 and 24, as well as the south poles of magnets in 18 and 22, respectively begin to repel each other, pushing the incremental weight plate 20 away from the weight plate 12. Thus, the user need only apply a relatively easy twisting motion to the incremental weight placed 20 rather then pull the plates apart. The result is that the incremental weight plate seemingly “pops off” the dumbbell.
To prevent the rotating magnets from marring the surfaces of the weight plate 12 and the incremental weight plates 20, the magnets are preferably recessed from the surfaces of the respective plates by 10 thousandths of an inch or so. Those skilled in the art will recognize that a greater number of magnets could be used, and that they can be positioned differently than those shown in the Figures. Regardless of the number of magnets or their respective positions, the respective poles of the magnets are utilized to attract or repel mating magnets to firmly hold the incremental weight plate on the dumbbell and to assist the user in removing the incremental weight plate, as the case may be. By properly selecting the number of magnets and their relative positions, decoupling with a rotation of less than 180° can be effected.
A second embodiment of the invention is shown in FIGS. 8-11. FIG. 8 is a front elevation view of a dumbbell of the “adjustable” type, wherein weight plates are secured on the bar by removable collars that permit the user to add or remove individual weight plates to the dumbbell. FIG. 9 is a left side elevation view of the dumbbell of FIG. 8, and FIG. 10 is a front elevation view of the dumbbell of FIG. 8, showing the incremental weight plate 34 positioned for mounting onto the dumbbell in accordance with the invention.
In this embodiment, outer weight plates 32 and incremental weight plates 34 are mounted on opposite ends of a shaft 35 that extends through the dumbbell handle 37. As will become clear, the outer weight plates 32 need not be magnetically responsive but can, instead, be made of polyurethane or other commonly utilized plastic material such as that found in less expensive dumbbell sets.
FIG. 11 is a left side elevation view of the right incremental weight plate 34 of FIG. 8, showing two magnets 38. As before, one of the magnets has its south pole facing outward, while the other has its north pole facing outward.
The shaft 35 is of the known externally-threaded variety. Conventionally, weight plates are mounted on to the shaft and urged toward the dumbbell's handle until stopped by the collar 36 or a previously mounted way to plate. An internally threaded nut or other such fastening device is then rotated onto the shaft until securing contact is made with the way to plate.
In accordance with the invention, a sleeve 40 is mounted on to the shaft 35. The sleeve preferably has a “T”-shaped cross-section, comprising an internally-threaded cylindrical portion 41 that is tightened onto the threaded shaft 35, and a leading base portion 42 of relatively greater diameter that butts up against the outer plate 32. The base portion 32 is formed from magnetically responsive material. Alternatively, the base portion 32 can include two or more magnets that respectively present a north and a south pole to the magnets of the incremental weight plate 34 for the coupling/decoupling affect previously described. In either case, the base portion 42 provides a magnetically responsive seat for the incremental weight plate 34 regardless of whether the outer plate 32 is made of magnetically-responsive material or not. Further, the base portion 42 provides a wear surface that prevents the outer plate 32 from being marred or damaged by the incremental plate 34, particularly when the outer plate 32 is plated or coated with an aesthetically pleasing layer of material.
The sleeve 40 may be tightened onto the shaft 35 by mounting the sleeve and magnetically coupled incremental weight plate 34 together as a unit, and utilizing the incremental plate 34 as a handle in a jar-lid tightening manner. To enable the sleeve 40 to be more firmly tightened onto the shaft, however, a series of longitudinally-extending grooves 44 are preferably formed in the cylindrical portion 41 of the sleeve, as best shown in FIG. 10, for gripping by complimentary surfaces of a tightening tool. FIG. 10 is a right side elevation view of the sleeve 40.
FIG. 12 illustrates a third embodiment of the invention. FIG. 12 is a front elevation view of a dumbbell of the “fixed weight” type, wherein weight plates 52 are permanently secured on the ends of a shaft that extends through the dumbbell handle 58. FIG. 13 is a side elevation view of the dumbbell of FIG. 12. Again, the weight plates 52 may be magnetically responsive or not. An annular, longitudinally-extending cylindrical sleeve 54 having a relatively larger diameter base portion 60 is affixed to the dumbbell at each end of the dumbbell via a respective hex bolt 59 that is inserted through the sleeve and threaded into an internally threaded end region of the shall to secure the sleeve 54 and weight plate 52 against the collar 56 formed at each end of the handle 58. Incremental weight plates can then me added and removed as described above, preferably but not necessarily utilizing magnets in the base portion 60 to repel the incremental weight plate when the incremental weight plate is rotated to bring its magnets into general alignment with the like-pole of opposing respective magnets in the base portion.
The invention herein is not limited to dumbbells or barbells. It can, for example be applied to cable-type exercise equipment. FIG. 14 is a rear elevation view in schematic of a cabled exercise device constructed in accordance with a fourth embodiment of the invention. An adjustable stack of weight plates 70 is lifted by a user who is pulling them upward by a cable 72 via a pulley system or other means known in the art. The stack of weight plates is guided by guide rods 73, which guide the stack's movement vertically, and keep the plates evenly stacked as they move. “Sleeves” with magnetically-responsive base portions may be affixed, as at 74, to the topmost weight plate to accommodate incremental weight plates, thereby offering a total poundage that falls between the increments of weight offered by the stack. The base portions of the “sleeves” may include magnets, as described above, to repel the incremental weight plate when the incremental weight plate is appropriately rotated, or the sleeve. The “sleeves” need not be annular in this application, and the term “sleeve” has been used only for consistency of terminology with respect to embodiments described above.
Alternatively, the “sleeves” of this embodiment can be positioned as at 76, with the incremental weight plates being held magnetically above the stack until needed, and then being selectively decoupled from the “respective” sleeve and guided vertically about the respective guide rod 73 from the “sleeve” to the weight plate stack. Once again, the decoupling action can be purely manual, or the “sleeves” can include magnets in their base portions to repel the incremental weight plate when the incremental weight plate is suitable rotated, as described earlier.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as will be defined by appended claims.
Patent Application
20070298940
