Electro-mechanical actuator

An electro-mechanical actuator, comprising:

• a body formed of a magnetically-permeable material and having an annular chamber therewithin, said body having an outer portion arranged radially outwardly of said chamber and having an inner portion arranged radially inwardly of said chamber, said body having an opening therethrough which communicates with said chamber, said body having first and second surfaces arranged in spaced facing relation to one another;
• an annular armature having one magnetic portion arranged within said chamber and having another non-magnetic portion penetrating said body opening, said armature having a first surface arranged to face said body first surface and having a second surface arranged to face said body second surface, any space between said body first surface and said armature first surface defining a first air gap and any space between said body second surface and said armature second surface defining a second air gap;
• suspension means arranged between said body and armature for mounting said armature for movement between said first and second body surfaces;
• a coil mounted on said body and selectively operable to create a magnetic field in at least one flux path which passes through said first and second air gaps;
• and
• at least one permanent magnet mounted on said body, each magnet being operatively arranged to create through said body and armature a first magnetic loop passing through one of said air gaps but not the other of said air gaps and a second magnetic loop passing through said other air gap but not said one air gap.