Method and apparatus for magnetically coupling incremental weights to exercise apparatus

1. A dumbbell comprising:

a bar that extends generally axially between opposing end regions;

a weight plate mass mounted about the bar at each end region, the axially outermost surface of each weight plate mass having at least a pair of magnetic regions, one of said regions having a north magnetic pole facing axially outward, and the second magnetic region having a south magnetic pole facing axially outward; and

means for retaining the mounted weight plate mass at the respective end regions to define a handle region axially inward of the end regions that can be gripped by a user during exercise movement of the dumbbell.

2. The dumbbell of claim 1 further including an incremental weight plate sized to be mounted on the axially outermost surface of the weigh plate mass, the incremental weight plate having a pair of magnetic regions positioned to face axially inward when the incremental weight plate is mounted on the dumbbell, one of said regions presenting a north magnetic pole to the weight plate mass, and the second magnetic region presenting a south magnetic pole to the weight plate mass, the magnetic regions of the incremental weight plate being positioned to generally adjacently overlie the magnetic regions of the weight plate mass so that the incremental weight plate is magnetically secured to the weight plate mass.

3. The dumbbell of claim 2 wherein the magnetic regions of the incremental weight plate are positioned to generally adjacently overlie the magnetic regions of the weight plate mass so that the incremental weight plate is magnetically repelled from the weight plate mass.

4. The dumbbell of claim 1 further including an incremental weight plate mounted to at least one end region and having an axially inwardly-facing magnetic pole positioned to selectively couple magnetically to either of the two magnetic regions of the weight plate mass.

5. The dumbbell of claim 1 wherein the bar extends axially outward of the weight plate mass at each end region sufficiently to accept a generally annular incremental weight plate having a generally central through hole that accommodates the bar.

6. The dumbbell of claim 1 wherein the magnetic regions are positioned generally diametrically opposite about the bar.

7. The dumbbell of claim 6 further including a generally annular incremental weight plate having a generally central bar-accommodating through-hole and sized to be mounted on the axially outermost surface of the weigh plate mass, the incremental weight plate having a pair of magnetic regions positioned to be at diametrically opposite side of the bar and to face axially inward when the incremental weight plate is mounted on the dumbbell, one of said regions presenting a north magnetic pole to the weight plate mass, and the second magnetic region presenting a south magnetic pole to the weight plate mass, the magnetic regions of the incremental weight plate being positioned to generally adjacently overlie the magnetic regions of the weight plate mass so that the incremental weight plate can be selectively magnetically secured to and magnetically repelled from the weight plate mass.

8. The dumbbell of claim 1 wherein at least some of the magnetic regions of the weight plate mass are positioned generally diametrically opposite about the bar.

9. A dumbbell comprising:

a bar that extends generally axially between opposing end regions,

a weight plate mass mounted about the bar at each end region,

means for retaining the mounted weight plate mass at the respective end regions to define a handle region axially inward of the end regions that can be gripped by a user during exercise movement of the dumbbell, and

at least one incremental weight plate mountable on the dumbbell,

the weight plate mass and the incremental weight plate having respective magnetic regions that cause the incremental weight plate to be magnetically secured to the weight plate mass through the magnetic coupling between their respective magnetic regions when the incremental weight plate is in a first position with respect to the weight plate mass, and to be magnetically repelled from the weight plate mass through the magnetic interaction of their respective magnetic regions when the incremental weight plate is in a second position with respect to the weight plate mass.

10. The dumbbell of claim 9 wherein the incremental weight plate has a through-hole for mounting the incremental weight plate on the bar.

11. The dumbbell of claim 10 wherein

one of the weight plate mass and the incremental weight plate has a first magnetic pole region presenting the other of the weight plate mass and incremental weight plate with a magnetic pole having a polarity selected from the group consisting of a North pole and a South pole to which said other is magnetically securable when the incremental weight plate is mounted on the dumbbell;

the other of the weight plate mass and incremental weight plate has a second magnetic pole region presenting a magnetic pole of the same polarity towards said one of the weight plate mass and incremental weight plate when the incremental weight plate is mounted on the dumbbell,

the first and second magnetic pole regions being positioned so that the incremental weight plate is magnetically repelled from the weight plate mass by the interaction of the first and second magnetic pole regions when the incremental weight plate is rotated about the bar from the first position to the second position.

12. The dumbbell of claim 11 wherein the weight plate mass includes

at least one weight plate mounted about the bar at each end region, and

a sleeve mounted about the bar at each end region axially outward of said at least one weight plate said sleeve having a central generally axially-extending opening sized to fit about the bar and including (1) a relatively axially outward, axially-extending, generally cylindrical portion sized to be circumscribed by the through-hole of the mounted incremental weight plate when the incremental weight plate is mounted onto the dumbbell, and (2) a relatively axially inward base portion of relatively greater exterior diameter than the generally cylindrical portion that is comparatively closer to said at least one weight plate than the generally cylindrical portion and has least one axially outward-facing magnetic pole region for magnetically repelling the mounted incremental weight plate from the weight plate mass when the incremental weight plate is in the second position.

13. The dumbbell of claim 9 wherein

one of the weight plate mass and the incremental weight plate has a first magnetic pole region presenting the other of the weight plate mass and incremental weight plate with a magnetic pole having a polarity selected from the group consisting of a North pole and a South pole to which said other is magnetically coupled when the incremental weight plate is mounted on the dumbbell;

the other of the weight plate mass and incremental weight plate has a second magnetic pole region presenting a magnetic pole of the same polarity towards said one of the weight plate mass and incremental weight plate when the incremental weight plate is mounted on the dumbbell,

the first and second magnetic pole regions being positioned so that the incremental weight plate is magnetically repelled from the weight plate mass by the interaction of the first and second magnetic pole regions when the incremental weight plate is rotated about the axis of the bar into the second position.