Magnetic centrifugal clutch
AssigneeMagna Force, Inc.
InventorKarl J. Lamb
Life of this patent
Estimating the term…
Abstract
A magnetic coupling device has an electroconductive rotor presenting a band of electroconductive material and has a magnet rotor with permanent magnets which are slide-mounted to move radially outward responsive to centrifugal force in opposition to a spring bias. When the magnet rotor is stationary the magnets are radially inward of the orbit of the electroconductive band, and when the magnets have moved outwardly when the magnet rotor is rotating, the magnets are spaced by an air gap from the electroconductive band so that eddy currents are induced in the band resulting in coupling of the rotors. The electroconductive rotor preferably has two such bands positioned on opposite sides of the magnet rotor. The rotors may have sheaves mounted thereon.
Claims32
A centrifugal clutch comprising:
- a first rotor having a first rotary axis and having a band of non-ferrous electroconductive material spaced outwardly from said axis by a radial distance;
- a second rotor facing said first rotor, and having a second rotary axis aligned with said first rotary axis;
- and permanent magnets moveably mounted on said second rotor such as to move outwardly relative to said second rotary axis responsive to centrifugal force resulting from rotation of said second rotor from an inactive inner position to an active outer position wherein poles of said magnets are spaced by an air gap from said band, said magnets being located mostly within a circle on said centered on said second axis and having a radius equal to said radial distance when said magnets are in said inner position;
- and force applying components on said second rotor applying a return force to said magnets directed inwardly toward said second axis for returning said magnets to their inner position when said second rotor is not rotating, said return force being insufficient to overcome said centrifugal force when said second rotor is rotating at least at a preset speed.
A centrifugal clutch comprising:
- a first rotor having a rotary first axis and having first and second bands of non-ferrous electroconductive material each spaced outwardly from said axis by a radial distance, said bands being axially spaced apart and facing one another;
- a second rotor centered on said first axis and extending radially between said bands, said second rotor having a second rotary axis aligned with said first axis;
- permanent magnets;
- holders carrying said permanent magnets and slide mounted on said second rotor for radial movement between an inactive inner position in which said magnets are substantially within the perimeter of a circle having said radial distance as a radius and an active outer position in which said magnets are substantially outside said circle and spaced by air gaps from said bands;
- and forcing applying elements extending between said second rotor and said holders for applying a return force to said holders toward said inner position, whereby said holders are moved by centrifugal force to said outer position when said second rotor is rotated at a speed in which the centrifugal force counters said return force, and said holders are moved to said inner position by said force applying elements when said second rotor is stationary.
A coupling device comprising:
- a first rotor having a rotary axis and two axially spaced bands of non-ferrous electroconductive material facing one another and spaced outwardly from said axis;
- a second rotor centered on said axis;
- permanent magnets each having oppositely directed poles and being mounted on said second rotor, said magnets having a position between said bands and having their poles spaced by air gaps from said bands, alternate of said magnets having their poles reversed;
- and a sheave mounted on said first rotor and centered on said axis.
Dependencies are inferred from the claim text.