Adjustable-torque magnetic brake

Claim 2

An adjustable-torque magnetic device for dynamically braking a rotary member comprising: a multipole magnet of generally cylindrical form and having circularly arranged poles, a pair of magnetic circuit elements, one on each side of and coaxial with said magnet, for providing flux paths between opposite polarity poles of said magnet, one of said elements being mounted for rotation and operatively connected to said rotary member, and flux gate means interposed between said magnet and said one of said circuit elements and spaced from said one of said circuit elements and being adapted for rotary adjustment relative to said magnet between a maximum output torque position wherein magnetic flux paths to said circuit elements are completed through said flux gate means and a minimum torque position wherein magnetic flux in each of said flux paths is shunted through said flux gate means to bypass said one of said circuit elements.

Claim 3

A device as defined in claim 1 wherein said magnet has four poles, each in the form of a 90* circular sector and wherein said flux gate means comprises a disc of magnetizable material with four 90* gate sectors defined by four radially aligned non-magnetic segments.

Claim 4

A device as defined in claim 2 wherein said flux gate disc is adapted to be operatively connected to a fixed mounting structure and wherein said magnet is adapted for angular adjustment about its axis relative to said flux gate disc through a 45* angle between a position with said pole sectors in registration with said flux gate sectors and a position wherein said flux gate sectors are centered between two adjacent pole sectors.

Claim 5

A device as defined in claim 1 wherein said multipole magnet is a permanent magnet.

Claim 6

A device as defined in claim 1 wherein said multipole magnet is an electromagnet.

Claim 7

A device as defined in claim 1 wherein said one of said magnetic circuit elements is formed of high hysteresis loss material.

Claim 8

A device as defined in claim 1 wherein said one of said magnetic circuit elements is formed of magnetically soft material in which magnetic particles are confined in the space between said one of said magnetic circuit elements and said flux gate disc.

Claim 9

An adjustable-torque magnetic coupling for dynamically braking a rotating member comprising: a multipole, permanent magnet of generally cylindrical form and having poles in the form of circular sectors, a pair of coaxial circuit discs axially spaced on opposite sides of said magnet for providing magnetic flux paths between adjacent pole sectors, one of said discs being of high hysteresis loss material and connected to said rotary member, and a flux gate disc interposed between said magnet and said one of said circuit discs, and having gate portions defined by radial slots, said gate portions generally corresponding in shape to said pole sectors, said flux gate disc being adapted for rotary adjustment relative to said magnet between a maximum torque position with said flux gate sectors aligned with said pole sectors whereby magnetic flux paths are compleTed through said adjacent circuit disc, and a minimum torque position with said flux gate sectors generally centered at the boundary between adjacent pole sectors whereby magnetic flux is shunted from said paths through said flux gate sectors.

Claim 10

An adjustable-torque magnetic coupling for dynamically braking a rotating member comprising: a multipole, permanent magnet of generally cylindrical form and having poles in the form of circular sectors, a pair of coaxial circuit discs axially spaced on opposite sides of said magnet for providing magnetic flux paths between adjacent pole sectors, one of said discs being of high hysteresis loss material and connected to said rotary member, and a flux gate disc interposed between said magnet and said one of said circuit discs, and having gate portions defined by radial slots, said gate portions generally corresponding in shape to said pole sectors, said flux gate disc being adapted for rotary adjustment relative to said magnet between a maximum torque position with said flux gate sectors aligned with said pole sectors whereby magnetic flux paths are compleTed through said adjacent circuit disc, and a minimum torque position with said flux gate sectors generally centered at the boundary between adjacent pole sectors whereby magnetic flux is shunted from said paths through said flux gate sectors.

Claim 11

An adjustable-torque dynamic coupling for applying magnetic braking torque to a rotary member comprising: a multipole permanent magnet of generally cylindrical form and having opposite end faces and at least four symmetrical pole sectors, a circuit disc affixed to one end face of said magnet and coaxial therewith, a flux gate disc positioned coaxial with and adjacent the opposite end face of said magnet and having flux gate sectors magnetically independent from each other, said flux gate sectors corresponding in number to said magnetic poles, said magnet and flux gate flux being adapted for angular adjustment relative to one another about their axis between a first position wherein said flux gate sectors are in matching alignment with said pole sectors and a second position wherein said flux gate sectors are centered approximately midway between two pole sectors, and an output circuit disc located coaxial with, spaced from, and adjacent said flux gate disc and connected to said rotary member whereby when said flux gate disc is in said first position, magnetic flux to and from each pole sector passes through a flux gate sector to and from said output circuit disc and when said flux gate disc is in said second position magnetic flux is shunted through said flux gate sectors to bypass said output circuit disc.

Claim 12

An adjustable-torque dynamic coupling for applying magnetic braking torque to a rotary member comprising: a multipole permanent magnet of generally cylindrical form and having opposite end faces and at least four symmetrical pole sectors, a circuit disc affixed to one end face of said magnet and coaxial therewith, a flux gate disc positioned coaxial with and adjacent the opposite end face of said magnet and having flux gate sectors magnetically independent from each other, said flux gate sectors corresponding in number to said magnetic poles, said magnet and flux gate flux being adapted for angular adjustment relative to one another about their axis between a first position wherein said flux gate sectors are in matching alignment with said pole sectors and a second position wherein said flux gate sectors are centered approximately midway between two pole sectors, and an output circuit disc located coaxial with, spaced from, and adjacent said flux gate disc and connected to said rotary member whereby when said flux gate disc is in said first position, magnetic flux to and from each pole sector passes through a flux gate sector to and from said output circuit disc and when said flux gate disc is in said second position magnetic flux is shunted through said flux gate sectors to bypass said output circuit disc.

Claim 13

A device as defined in claim 9 including magnetic particles confined in the space between said flux gate disc and said output circuit disc.

Claim 14

A device as defined in claim 10 in which said output circuit disc is formed of a magnetically soft material.

Claim 15

A device as defined in claim 9 in which said output circuit disc is formed of a high hysteresis loss material.