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US 6,702,221 B2Granted
Magnetorheological fluid actively controlled bobbin tensioning apparatus
AssigneeNorthrop Grumman Corporation
InventorsDavid S. Haber, Emil M. Shtarkman
Life of this patent
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Abstract
A method and apparatus for controlling the tension in a bobbin assembly having a supply bobbin with yarn thereon. As the yarn is fed to a drive bobbin, a magnetic field is variably applied to magnetorheological fluid to apply resistance to the supply bobbin as it rotates thereby controlling the tension on the yarn.
Claims17
An apparatus for controlling tension in yarn, the apparatus comprising:
- a housing having a sealed fluid chamber;
- a supply bobbin having the yarn wrapped thereon, the supply bobbin extending from the housing along a first longitudinal axis;
- a device coupled to the supply bobbin for rotation therewith, the device including a first surface formed generally perpendicular to the first longitudinal axis;
- magnetorheological fluid disposed within the fluid chamber of the housing and adjacent at least a part of the device;
- and
- a first pair of electromagnetic coils disposed adjacent the first surface of the device for supplying a magnetic field to the magnetorheological fluid to apply resistance to the device as it rotates with the supply bobbin to thereby control the tension on the yarn.
3 more elements
A method for controlling the tension of yarn, the method comprising:
- providing a supply bobbin with yarn wrapped on an exterior surface thereof;
- rotating the supply bobbin;
- generating a velocity signal indicative of the speed of rotation of the supply bobbin;
- sending the velocity signal to an electronic control unit, the control unit operable to compare the velocity signal to a predetermined velocity and generate an output signal indicative thereof;
- and
- energizing a first pair of electromagnetic coils in response to the output signal to thereby apply a magnetic flux through a magnetorheological fluid disposed proximate the supply bobbin, the maqnetorheological fluid operable to apply resistance to the supply bobbin to control rotation of the supply bobbin and adjust the tension on the yarn.
3 more elements
Dependencies are inferred from the claim text.