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US 6,275,129 B1Granted
Shim assembly for a magnet and method for making
AssigneeGeneral Electric Company
InventorJohannes Martinus van Oort
Life of this patent
Estimating the term…
Abstract
A shim assembly for a magnet and a method for making a shim assembly. A first spool has a shaft, a first rim attached to a first longitudinal end of the shaft, and a second rim attached to a second longitudinal end of the shaft. A first magnetizable tape has a predetermined length and is wound around the shaft longitudinally between the first and second rims.
Claims16
A shim assembly for a pole face of a magnet, said pole face having a longitudinal axis, and said shim assembly comprising:
- a) a non-magnetizable shim tray disposed proximate said pole face, wherein said non-magnetizable shim tray has a plurality of generally-circular surface holes each having an axis generally parallel to said longitudinal axis, each having an opening facing away from said pole face, and each having a circumferential flat portion disposed only longitudinally proximate said opening;
- b) a first non-magnetizable spool disposed in a first one of said surface holes, having an axis generally parallel to said longitudinal axis, having a generally-longitudinally-extending and generally-circular-cylindrical-shaped shaft, and having generally-identical, generally-radially-extending, and generally-circular-shaped first and second rims, wherein said shaft has generally-opposing first and second longitudinal ends, wherein said first rim is attached to said first longitudinal end of said shaft and has a first circumferential flat region generally matching in shape said circumferential flat portion, and wherein said second rim is attached to said second longitudinal end of said shaft and has a second circumferential flat region generally aligned with said first circumferential flat region and generally matching in shape said circumferential flat portion;
- and
- c) a first magnetizable tape having a first predetermined length and wound around said shaft longitudinally between said first and second rims.
1 more element
A method for making a shim assembly for a magnetic resonance imaging (MRI) magnet, said method comprising the steps of:
- a) obtaining a first non-magnetizable plastic spool;
- b) obtaining a first magnetizable tape including a magnetizable foil layer and a pressure-sensitive-adhesive-tape layer attached to said magnetizable foil layer;
- c) determining a first length of said first magnetizable tape that provides a predetermined shim strength;
- d) winding said first magnetizable tape on said first non-magnetizable plastic spool;
- and
- e) cutting said wound first magnetizable tape to said determined first length.
3 more elements
A shim assembly for a magnet, said shim assembly comprising:
- a) at least one spool having a generally-longitudinally-extending shaft, wherein said spool is a non-magnetizable spool;
- b) at least one magnetizable tape having a respective predetermined length and wound around said spool, wherein said magnetizable tape comprises a magnetizable foil layer and a pressure sensitive-adhesive-tape layer attached to said magnetizable foil layer, and wherein a portion of said pressure-sensitive-adhesive-tape layer is attached by pressure-adhesion to said shaft;
- and
- c) a shim tray having a plurality of cavities, wherein said at least one spool is disposed in a selected one of said cavities so as to position said spool in a spaced relationship with said magnet when said shim tray is positioned in juxtaposition with said magnet as part of said shim assembly.
1 more element
A method for making a shim assembly for a magnet, said method comprising the steps of:
- a) obtaining at least one spool having a generally-longitudinally-extending shaft, wherein said spool is a non-magnetizable spool;
- b) preparing at least one magnetizable tape, said tape being selected to provide a predetermined shim strength, wherein said magnetizable tape comprises a magnetizable foil layer and a pressure-sensitive-adhesive-tape layer attached to said magnetizable foil layer;
- c) winding said at least one magnetizable tape on said at least one spool;
- and
- d) assembling said at least one spool in a shim tray having a plurality of cavities, wherein said at least one spool is disposed in one of said cavities so as to affect the magnetic field generated by said magnet.
2 more elements
Dependencies are inferred from the claim text.