Exercise apparatus with three dimensional motion

1. Exercise apparatus comprising a four-bar mechanism comprising first, second, third, and fourth links connected respectively by first, second, third and fourth pivot joints, said first link being connected to said second link at said first pivot joint, said second link being connected to said third link at said second pivot joint, said third link being connected to said fourth link at said third pivot joint, said fourth link being connected to said first link at said fourth pivot joint, said first and second links pivoting relative to each other about a first pivot axis at said first pivot joint, said second and third links pivoting relative to each other about a second pivot axis at said second pivot joint, said third and fourth links pivoting relative to each other about a third pivot axis at said third pivot joint, said fourth and first links pivoting relative to each other about a fourth pivot axis at said fourth pivot joint, one of said links having a user-engagement surface guiding movement of a user in three dimensional motion via the first, second, third and fourth links pivoting about their respective pivot axes, wherein said first, second, third, and fourth pivot axes all go through a common point.

2. The exercise apparatus according to claim 1 wherein said first link is a ground link, said second link is a first grounded link, said third link is a coupler link, and said fourth link is a second grounded link.

3. The exercise apparatus according to claim 2 wherein said second link is an input link, and said fourth link is a follower link.

4. The exercise apparatus according to claim 2 wherein said first and fourth pivot axes define a 900 angle therebetween at said common point.

5. The exercise apparatus according to claim 2 wherein said coupler link has said user-engagement surface.

6. The exercise apparatus according to claim 5 wherein said coupler link comprises first and second segments on distally opposite sides of said second pivot joint and extending in distally opposite directions from said second pivot joint, said first segment extending from said second pivot joint to said third pivot joint, said second segment providing said user-engagement surface.

7. The exercise apparatus according to claim 2 wherein said second link is a crank input rotating in a rotary motion plane, said fourth link is a rocker follower rocking in a rocking motion plane, said rotary motion and rocking motion planes being noncoincident.

8. The exercise apparatus according to claim 7 wherein said rotary motion and rocking motion planes are nonparallel.

9. The exercise apparatus according to claim 7 wherein said rotary motion plane is transverse to said rocking motion plane.

10. Exercise apparatus comprising a dual four-bar mechanism comprising first and second four-bar mechanisms, said first four-bar mechanism comprising first, second, third and fourth links connected respectively by first, second, third and fourth pivot joints, said first link being connected to said second link at said first pivot joint, said second link being connected to said third link at said second pivot joint, said third link being connected to said fourth link at said third pivot joint, said fourth link being connected to said first link at said fourth pivot joint, said first and second links pivoting relative to each other about a first pivot axis at said first pivot joint, said second and third links pivoting relative to each other about a second pivot axis at said second pivot joint, said third and fourth links pivoting relative to each other about a third pivot axis at said third pivot joint, said fourth and first links pivoting relative to each other about a fourth pivot axis at said fourth pivot joint, said second four-bar mechanism comprising fifth, sixth, seventh, and eighth links connected respectively by fifth, sixth, seventh, and eighth pivot joints, said fifth link being connected to said sixth link at said fifth pivot joint, said sixth link being connected to said seventh link at said sixth pivot joint, said seventh link being connected to said eighth link at said seventh pivot joint, said eighth link being connected to said fifth link at said eighth pivot joint, said fifth and sixth links pivoting relative to each other about a fifth pivot axis at said fifth pivot joint, said sixth and seventh links pivoting relative to each other about a sixth pivot axis at said sixth pivot joint, said seventh and eighth links pivoting relative to each other about a seventh pivot axis at said seventh pivot joint, said eighth and fifth links pivoting relative to each other about an eighth pivot axis at said eighth pivot joint, one of said links of said first four-bar mechanism having a first user-engagement surface guiding movement of a user in three dimensional motion via the first, second, third and fourth links pivoting about their respective pivot axes, one of said links of said second four-bar mechanism having a second user-engagement surface guiding movement of said user in three dimensional motion via the fifth, six, seventh and eighth links pivoting about their respective pivot axes, wherein said first, second, third, fourth, fifth, sixth, seventh, and eighth pivot axes all go through a common point.

11. The exercise apparatus according to claim 10 comprising an upper body exercise apparatus, wherein said one link of said first four-bar mechanism provides said first user-engagement surface for the right hand of said user, and said one link of said second four-bar mechanism provides second user-engagement surface for the left hand of said user.

12. The exercise apparatus according to claim 10 wherein said first and fifth links are a common ground link, whereby said first and second four-bar mechanisms share the same said common ground link.

13. The exercise apparatus according to claim 12 wherein said first and fifth pivot axes are coincident.

14. The exercise apparatus according to claim 12 wherein said fourth and eighth pivot axes are coincident.

15. The exercise apparatus according to claim 10 wherein said first link is a first ground link, said second link is a first grounded link, said third link is a first coupler link, said fourth link is a second grounded link, said fifth link is a second ground link, said sixth link is a third grounded link, said seventh link is a second coupler link, and said eighth link is a fourth grounded link.

16. The exercise apparatus according to claim 15 wherein said second link is a first input link, said fourth link is a first follower link, said sixth link is a second input link, said eighth link is a second follower link, and said first and second ground links are common.

17. The exercise apparatus according to claim 15 wherein said first and fourth pivot axes define a first 90° angle therebetween at said common point, and said fifth and eighth pivot axes define a second 90° therebetween at said common point.

18. The exercise apparatus according to claim 15 wherein said first coupler link has said first user-engagement surface, and said second coupler link has said second user-engagement surface.

19. The exercise apparatus according to claim 18 wherein said first coupler link comprises first and second segments on distally opposite sides of said second pivot joint and extending in distally opposite directions from said second pivot joint, said first segment extending from said second pivot joint to said third pivot joint, said second segment providing said first user-engagement surface, and said second coupler link comprises third and fourth segments on distally opposite sides of said sixth pivot joint and extending in distally opposite directions from said sixth pivot joint, said third segment extending from said sixth pivot joint to said seventh pivot joint, said fourth segment providing said second user-engagement surface.

20. The exercise apparatus according to claim 10 wherein the sum of the angles respectively between said first, second, third, and fourth pivot axes is less than 360°, and wherein the sum of the angles respectively between said fifth, sixth, seventh, and eighth pivot axes is less than 360°.

21. The exercise apparatus according to claim 10 wherein said second and sixth links are respective first and second crank inputs 180° out of phase with each other.