Electromagnetic apparatus for producing linear motion
First Claim
1. An electromagnetic piston and cylinder device comprising a cylinder assembly including an elongate cylinder of magnetic material and means for producing a cylinder magnetic field pattern comprising a series of alternate radially directed magnetic poles along the length of the cylinder, a piston member mounted within the cylinder assembly and having means for creating a radial magnetic field pattern for cooperating with the cylinder magnetic field pattern such that the magnetic fields are contained within the cylinder, a means for modulating the strength and polarity of at least one of the cylinder or piston magnetic field patterns whereby to cause relative linear thrust between the cylinder assembly and piston member, characterised in that the means for producing the cylinder magnetic field pattern comprises means for generating radial magnetic fields within the interior of the cylinder, in that the piston member is shorter in axial length than the cylinder, in that the cylinder is closed at both ends by end members with the piston member being provided with a rod extending through one of the end members, and in that the interior of the cylinder communicates with a fluid reservoir.
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Accused Products
Abstract
An electromagnetic piston and cylinder device for producing linear motion has a cylinder provided with a plurality of magnetic devices along its length for producing radial magnetic fields of alternative polarity. The piston is also provided with at least one magnetic member producing a further radial field and there is control means for carrying piston radial field or the cylinder radial fields to alternate whereby to cause relative movement between the piston and cylinder. The piston and cylinder device is preferably sealed but connected to a fluid reservoir whereby the device operates as a combined spring and actuator.
199 Citations
22 Claims
- 1. An electromagnetic piston and cylinder device comprising a cylinder assembly including an elongate cylinder of magnetic material and means for producing a cylinder magnetic field pattern comprising a series of alternate radially directed magnetic poles along the length of the cylinder, a piston member mounted within the cylinder assembly and having means for creating a radial magnetic field pattern for cooperating with the cylinder magnetic field pattern such that the magnetic fields are contained within the cylinder, a means for modulating the strength and polarity of at least one of the cylinder or piston magnetic field patterns whereby to cause relative linear thrust between the cylinder assembly and piston member, characterised in that the means for producing the cylinder magnetic field pattern comprises means for generating radial magnetic fields within the interior of the cylinder, in that the piston member is shorter in axial length than the cylinder, in that the cylinder is closed at both ends by end members with the piston member being provided with a rod extending through one of the end members, and in that the interior of the cylinder communicates with a fluid reservoir.
- 13. An electromagnetic piston and cylinder device comprising a cylinder assembly including an elongate cylinder of magnetic material and means for producing a cylinder magnetic field pattern comprising a series of alternate radially directed magnetic poles along the length of the cylinder, a piston member mounted within the cylinder assembly and having means for creating a radial magnetic field pattern for cooperating with the cylinder magnetic field pattern such that the magnetic field are contained within the cylinder, a means for modulating the strength and polarity of at least one of the cylinder or piston magnetic field patterns whereby to cause relative linear thrust between the cylinder assembly and piston member, characterised in that the means for producing the cylinder magnetic field pattern comprises means for generating radial magnetic fields within the interior of the cylinder, and in that the means for producing the cylinder magnetic field pattern comprises means for generating radial magnetic fields within the interior of the cylinder, in that the piston member is shorter in the axial length that the cylinder, and in that the piston field pattern creating means comprise radially magnetised permanent magnets axially spaced from each other to create a central pole of one direction of magnetisation and two further poles spaced apart on either side of the central pole and having the opposite direction of magnetisation.
Specification