Patent ID: 6268667
Filing Date: 2001-07-31
Classification: F15B,H02K

Abstract:
An electromagnetic apparatus for producing a controlled axially directed force comprising:two relatively moveable tubular members adapted to slide telescopically one within the other;a plurality of annular coils fixed to at least a portion of an axial length of one of said relatively moveable members;current generating means for generating circumferential electric currents in said annular coils;means for producing a plurality of radially directed magnetic fluxes, the polarity of which alternates along at least a portion of the other of said relatively moveable tubular members;said current generating means includes controlling means for varying at least one of the frequency, the phase, and the amplitude of said electric currents in said annular coils so as to cause said electric currents and said magnetic fluxes to interact to provide a related resultant axial force tending to cause a relative motion between said two relatively moveable tubular members;each of said two relatively moveable tubular members have an open end, fitted one within the other, and an open distal end, terminating in a flange by means of which said tubular member can be sealably mounted on a respective relatively moveable portion of a structure so that an enclosed volume is defined between said two relatively moveable tubular members and the portions of said structure to which said tubular members are sealably attached.