Magnetic friction device
AssigneeGeneral Electric Company
InventorDavid L. Hoffman
Life of this patent
Estimating the term…
Abstract
A magnetic friction device for permitting one machine member to be moved relative to another by applying a predetermined force and for holding one member in a fixed position when the force is discontinued. One member is magnetically susceptible and has a smooth surface interfacing with but slightly spaced from a surface on the other member. The other member's surface has one or more recesses in which there are magnetic disks of a polymer impregnated with magnetic particles. The disks are attracted to the smooth surface to produce a design controlled predetermined frictional force.
Claims14
Apparatus comprising two members that are required to stay in a fixed position relative to each other when a force that has been applied to move one of the members has been discontinued,
- means for holding the members in proximity with each other with a gap between them but permitting one member to move in parallelism relative to the other,
- one of the members having a planar surface defined by magnetic material,
- the other member having a planar surface defined by nonmagnetic material and having a recess presented toward the planar surface of the magnetic material of said one member,
- a permanent magnet element having a planar surface and being contained in the recess of the other member, said element fitting closely within said recess but being movable in a direction perpendicular to its planar surface for being attracted to the magnetic material to develop a frictional force sufficient to prevent movement of one member relative to the other which force must be overcome to move one member relative to the other by manual application of force to one of said members, said magnet element being comprised of a polymer containing magnetized particles.
A magnetic brake device that allows rotation of one object relative to another object when a predetermined torque is applied to the one object and holds the one object in a fixed position relative to the other when the torque is removed, comprising:
- a first member for being mounted to one of the objects, said member being composed of magnetic material and having a planar surface,
- a second member for being mounted on the other object and being composed of nonmagnetic material, said second member having a surface in which there are recesses presented toward the planar surface on the first member,
- means for coupling said members for relative rotation and with a gap between their surfaces,
- a permanent magnet elements having planar surfaces in at least some of the recesses, respectively, of the second member, said elements being movable in a direction perpendicular to their planar surfaces for being attracted to the planar surface of the magnetic first member to develop a frictional force sufficient to prevent movement of one member relative to the other which force must be overcome with manual application of force to one member sufficient to produce enough torque to rotate one member relative to the other, said magnet elements being comprised of a polymer containing magnetized particles.
Dependencies are inferred from the claim text.