Patent ID: 8808096

Claim:
Apparatus for coupling force between first and second movable members, wherein the first movable member has a first array of alternating magnetic poles arranged thereon and the second movable member has a second array of alternating magnetic poles arranged thereon, wherein: magnetic flux coupling means is arranged between the first and second movable members, wherein there is a first spacing between the magnetic flux coupling means and the first movable member and a second spacing between the magnetic flux coupling means and the second movable member, wherein the magnetic flux coupling means comprises one or more coupling elements; and a vacuum chamber contains one of the first and second movable members, the vacuum chamber having a vacuum chamber wall, wherein the magnetic flux coupling means is incorporated in the vacuum chamber wall which separates the first and second movable members, wherein the vacuum chamber is arranged to enclose a vacuum around a flywheel and wherein each coupling element is segmented orthogonally to a direction of relative motion between the members.