Abstract: An electromagnetic machine (1) comprises an electrical conductor vane (7) disposed between two magnetic arrays (3). The electrical conductor vane (7) comprises a plurality of electrically insulated conductors (35), wherein when the conductors (35) are disposed in magnetic fields produced by the magnetic arrays (3) and when current flows in the conductors (35), an electromagnetic force is induced to cause movement of the magnetic arrays (3) relative to the electrical conductor vane (7) and wherein the set of conductors (35) substantially fills the gap between the magnetic arrays (3) through which the magnetic fields pass.

Abstract: A linear electromagnetic machine is described which comprises first and second substantially cylindrical parts arranged to move relative to each other along a common axis of motion. The first cylindrical part produces a spatially periodic radial magnetic field across an air gap, the magnetic field having a regular alternating polarity along or parallel to the axis of motion. The second cylindrical part comprises a plurality of laminar electrical conductors wrapped into cylindrical form and placed in the air gap to intercept the magnetic field, each of the laminar electrical conductors compromising a regular pattern of electrically conductive paths, the electrically conductive paths of the plurality of laminar electrical conductors being interdigitated together within the air gap.

Abstract: A rotary electromagnetic machine is described which comprises first and second substantially cylindrical parts arranged to move relative to each other about a common axis. The first cylindrical part produces a spatially periodic radial magnetic field across an air gap, the magnetic field having a regular alternating polarity around the circumference of the first cylindrical part. The second cylindrical part comprises at least one laminar electrical conductor wrapped into cylindrical form and placed in the air gap to intercept the magnetic field, the laminar electrical conductor comprising a regular pattern of electrically conductive paths within the air gap. In more general terms, rotary motors in which the wire coils are replaced by laminations of material in which patterned conducting paths are created are described. The conducting laminations are placed in the air gap between an mature and backing iron that is constructed so as to reduce eddy current losses.

Abstract: An electromagnetic machine (1) comprises an electrical conductor vane (7) disposed between two magnetic arrays (3). The electrical conductor vane (7) comprises a plurality of electrically insulated conductors (35), wherein when the conductors (35) are disposed in magnetic fields produced by the magnetic arrays (3) and when current flows in the conductors (35), an electromagnetic force is induced to cause movement of the magnetic arrays (3) relative to the electrical conductor vane (7) and wherein the set of conductors (35) substantially fills the gap between the magnetic arrays (3) through which the magnetic fields pass.

Abstract: A linear electromagnetic machine for generating a force acting between two members relatively movable along an axis, one of which is capable of producing a magnetic field the direction of at least part of which extends substantially radially of the said axis and the other of which comprises or includes a conductor, conveniently in the form of a coil, in which an electric current can flow substantially perpendicularly of the magnetic field so as to generate a force between the two members substantially parallel to the axis. The radial magnetic field is generated by permanent magnets orientated with their direction of magnetisation axially, the pole pieces acting to concentrate the magnetic flux to follow a radial path through the coils.

Abstract: A suspension system comprises a gas spring formed by two cylindrical members, one sliding within the other in combination with an electromagnetic device for applying force to or absorbing force from the gas spring under electrical control. Preferably, the gas spring and electromagnetic unit are formed as a single composite unit. The system may be used in fully-active mode e.g. in a vehicle suspension system or simply as a variable damper.

Abstract: Fire suppressant apparatus comprises a container (11) which may be spherical or cylindrical with domed ends, housing a liquid such as water in an interior chamber (25) and having low pressure nozzles (19, 20) housed in recesses covered by caps or covers (26, 27). A gas generator (22) is also located within the chamber (25) and contains a stable combustible material (21) which can be ignited by an ignitor (26) triggered by a sensor (28). The gas generated by combustion of the material (21) drives the water out through the nozzles (19, 20) to form fine droplets the majority of which are in the region of 50 &mgr;m without creating a high pressure within the chamber (25). The burn time of the gas generator material is 15 to 20 seconds so that a mist or fog lasting at least this duration is generated in the protected environment and can be carried to the seat of a fire by convection currents within this environment.

Abstract: A linear electromagnetic machine for generating a force acting between two members relatively movable along an axis, one of which is capable of producing a magnetic field the direction of at least part of which extends substantially radially of the said axis and the other of which comprises or includes a conductor, conveniently in the form of a coil, in which an electric current can flow substantially perpendicularly of the magnetic field so as to generate a force between the two members substantially parallel to the axis. The radial magnetic field is generated by permanent magnets orientated with their direction of magnetization axially, the pole pieces acting to concentrate the magnetic flux to follow a radial path through the coils.

Abstract: A linear electromagnetic machine for generating a force acting between two members relatively movable along an axis, one of which is capable of producing a magnetic field the direction of at least part of which extends substantially radially of the said axis and the other of which comprises or includes a conductor, conveniently in the form of a coil, in which an electric current can flow substantially perpendicularly of the magnetic field so as to generate a force between the two members substantially parallel to the axis. The radial magnetic field is generated by permanent magnets orientated with their direction of magnetisation axially, the pole pieces acting to concentrate the magnetic flux to follow a radial path through the coils.

Abstract: An apparatus for imparting motion to a load comprises means for applying a force to the load and a compliant support for the load, in which there are provided means for effecting dynamic variation of the compliance of the support during operation of the apparatus so as to optimise the power efficiency. The apparatus may be capable of controlling relative motion in a plurality of degrees of freedom between a platform and a reference plane, the compliant means acting to support the weight of the platform, and the force-applying means being one or more actuators for applying perturbing forces between the platform and the reference plane. Control means act to control one or more actuators to move in one direction or the other to displace the platform with respect to the reference plane. At least part of the compliant supports may be a gas spring and in one embodiment this is in the form of a bellows supporting the platform.

Abstract: Electromagnetic apparatus for producing an axially directed force comprising a stator having a plurality of axially spaced coils around a working volume within which an armature in the form of a free piston is axially displaceable, the armature having means for producing a magnetic field a substantially radially directed part of which intersects at least some of the coils of the stator such that a resultant axially directed force is generated when a current flows in the coils.

Abstract: Sealed telescoping tubes are electromagnetically and fluidly actuated to provide linear motion and withstand loading. One of the tubes may be connected to a pressure or vacuum source, and the other sealed to a fixture to provide variable volume load augmentation in addition to electromagnetic actuation. Alternatively, both tubes may be sealed to provide a pneumatic or hydraulic spring with electromagnetic actuation, and the sealed tubes may also be connected to a pressure or vacuum source for load augmentation. A bearing may be used in conjunction with the seal between the tubes to provide resistance to traversal loads. The electromagnetic actuation includes a helical arrangement of coils or permanent magnets to provide linear motion or resistance. The coils can be arranged to be connected to a conventional multi-phase motor drive.

Abstract: A passive transponder for use in an interrogator-responder communication system is disclosed, including a first signal receiving element having a variable reflection property, a code signal generator for supplying a code signal, a modulating device responsive to the code signal for varying the signal reflection property of the first signal receiving element, and a power supply for supplying direct-current operating power to the code signal generator and to the modulating device, the power supply including a second signal receiving element for receiving a second electromagnetic signal having a second frequency different from the first frequency, and an a-c to d-c converter for converting the second signal to direct-current power.