Electromagnetic friction coupling

Claim 2

A brake mechanism for accurately positioning a member to be braked comprising a first member, a second member rotatable relative to said first member, said first and second members having friction surfaces thereon which are engaged during braking of said member, means for establishing a magnetic field having lines of flux which develop a braking torque between said first and second members, a flux path, and means for intensifying the lines of flux in said flux path when one of said members is in a predetermined position and for substantially maximizing the braking torque developed between said first and second members for accurately stopping one of said members at a predetermined position said means for intensifying said lines of flux in said flux path including a plurality of first spaced apart conductive portions associated with said first member and a plurality of second spaced apart conductive portions associated with said second member, said first and second conductive portions intensifying said lines of flux in said flux path and substantially maximizing the braking torque between said first and second members when said first conductive portions are aligned with said second conductive portions.

Claim 3

A brake mechanism for accurately positioning a member to be braked as defined in claim 1 wherein said first conductive portions comprise a plurality of teeth on said first member, said teeth on said first member being operable to be aligned with said conductive portion on said second member thereby intensifying said lines of flux and said braking torque.

Claim 4

A brake mechanism for accurately positioning a member to be braked as defined in claim 2 wherein said second conductive portions comprise a plurality of teeth on said second member said teeth on said first and second members being movable relative to each other and operable to be aligned with each other to thereby intensify said lines of flux and said braking torque.

Claim 5

A brake mechanism for accurately positioning a member to be braked as defined in claim 3 wherein said teeth on said first and second members are equally spaced about the periphery of said first and second members respectively, and the number of teeth on said first member equals the number of teeth on said second member.

Claim 6

A brake mechanism for accurately positioning a member to be braked comprising a first member, a second member rotatable relative to said first member, said first and second members having friction surfaces thereon which are engaged during braking of said member, means for establishing a magnetic field having lines of flux which develop a braking torque between said first and second members, a flux path, means for intensifying the lines of flux in said flux path when one of said members is in a predetermined position and for substantially maximizing the braking torque developed between said first and second members for accurately stopping one of said members at a predetermined position, second means for establishing a magnetic field having lines of flux which develop a braking torque between said first and second members, a second flux path and second means for intensifying the lines of flux in said second flux path and substantially maximizing the braking torque developed between said first and second member for accurately stopping one of said members in a second predetermined position.

Claim 7

A brake mechanism for accurately positioning a member to be braked comprising a first member, a second member rotatable relative to said first member, said first and second members having friction surfaces thereon which are engaged during braking of said member, means for establishing a magnetic field having lines of flux which develop a braking torque between said first and second members, a flux path, means for intensifying the lines of flux in said flux path when one of said members is in a predetermined position and for substantially maximizing the braking torque developed between said first and second members for accurately stopping one of said members at a predetermined position, second means for establishing a magnetic field having lines of flux which develop a braking torque between said first and second members, a second flux path and second means for intensifying the lines of flux in said second flux path and substantially maximizing the braking torque developed between said first and second member for accurately stopping one of said members in a second predetermined position.

Claim 8

A brake mechanism for accurately positioning a member to be braked as defined in claim 5 further including a third member fixed relative to said first member, and wherein said second means for controlling the intensity of said lines of flux includes a plurality of third spaced apart conductive portions associated with said third member and a plurality of fourth spaced apart conductive portions associated with said second member, said third and fourth conductive portions intensifying said lines of flux and substantially maximizing said braking torque when said third and fourth conductive portions are aligned with each other.

Claim 9

A brake mechanism for accurately positioning a member to be braked as defined in claim 6 wherein said plurality of third spaced apart conductive portions comprises a plurality of teeth disposed on said third member and wherein the number of teeth on said third member equals the number of said fourth spaced apart conductive portions.

Claim 10

A brake mechanism for accurately positioning a member to be braked as defined in claim 5 wherein said means for establishing a magnetic field and said second means for establishing a magnetic field includes first and second coil means respectively, each of said coil means being independently energizable.

Claim 11

A brake mechanism for accurately positioning a member to be braked as defined in claim 8 wherein said first coil means is energizable to effect stopping of said second member in one of a plurality of first predetermined positions and said second coil is energizable to effect stopping of said second member in one of a plurality of second predetermined positions.

Claim 12

A brake mechanism for accurately positioning a member to be braked comprising a first member having a plurality of first spaced apart conductive portions thereon, a second member rotatable relative to said first member and having a plurality of second spaced apart conductive portions thereon, a flux path, an electrically energizable first coil being operable upon energization thereof to create a magnetic field having lines of flux which travel through said flux path between said first and second members, and friction surfaces on said first and second members which are engageable for stopping said rotational movement, said first and second conductive portions controlling the intensity of said lines of flux in said flux path and substantially maximizing the intensity of said lines of flux when said first and second conductive portions are aligned with one another and said second member is disposed in a predetermined position relative to said first member said lines of flux substantially maximizing the braking torque developed between said first and second members when the intensity of said lines of flux is maximized to thereby stop said relative movement when said first and second conductive portions are aligned with one another and said second member is accurately positioned relative to said first member.

Claim 13

A brake mechanism for accurately positioning a member to be braked comprising a first member having a plurality of first spaced apart conductive portions thereon, a second member rotatable relative to said first member and having a plurality of second spaced apart conductive portions thereon, a flux path, an electrically energizable first coil being operable upon energization thereof to create a magnetic field having lines of flux which travel through said flux path between said first and second members, and friction surfaces on said first and second members which are engageable for stopping said rotational movement, said first and second conductive portions controlling the intensity of said lines of flux in said flux path and substantially maximizing the intensity of said lines of flux when said first and second conductive portions are aligned with one another and said second member is disposed in a predetermined position relative to said first member said lines of flux substantially maximizing the braking torque developed between said first and second members when the intensity of said lines of flux is maximized to thereby stop said relative movement when said first and second conductive portions are aligned with one another and said second member is accurately positioned relative to said first member.

Claim 14

A brake mechanism for accurately positioning a member to be braked as defined in claim 10 further including a third member fixed relative to said first member, a second flux path, an electrically energizable second coil operable upon energization thereof to create a magnetic field having lines of flux which pass through said second flux path between said first and second members and means for controlling the intensity of said lines of flux in said second flux path and substantially maximizing the braking torque for stopping said relative movement when said second member is in a predetermined position relative to said third member, said means for controlling the intensity of said lines of flux in said second flux path including a plurality of third spaced apart conductive portions disposed on said third member and a plurality of fourth spaced apart conductive portions disposed on said second mEmber, said third and fourth conductive portions substantially maximizing the intensity of said lines of flux and said braking torque when said third and fourth conductive portions are aligned with one another and said second member is disposed in a predetermined position relative to said third member.

Claim 15

A brake mechanism for accurately positioning a member to be braked as defined in claim 11 wherein said first coil is operable upon energization thereof to stop said relative movement in a plurality of first spaced apart predetermined positions and said second coil is operable upon energization thereof to stop said relative movement in a plurality of second spaced apart predetermined positions which are distinct from said first spaced apart predetermined positions.