This invention relates to a magnetic apparatus for producing movement, preferably linear movement which is produced by intermittent actuation of electromagnets positioned in an aligned set of relatively movable paramagnetic members.
The prior art is replete with disclosures of linear actuators wherein electromagnets are periodically energized to provide linear movement. Typical examples of the prior art are discussed in and cited against the earlier patent applications mentioned above.
A particular objective of the present invention is to provide a system which is superior to prior art devices in that it will provide a high efficiency and a low weight-to-power ratio.
The invention disclosed herein is an improvement over my earlier devices in two primary respects. First, rather than providing electrical windings on all of the paramagnetic members in the system, the present system utilizes axially movable reactor members which are positioned between the electromagnets and do not themselves create a magnetic field. Second, the invention calls for the reduction of electrical consumption by providing for the gradual reduction of the magnetomotive force of the electromagnets while the gap is being closed by the action of such electromagnets. This reduction of magnetomotive force, while conserving energy, does not significantly reduce the force output of the device since, as the gaps between the members are closing, a lesser magnetomotive force is required to produce any given force of magnetic attraction.
More specifically, the invention relates in one sense to an apparatus which has a pair of relatively movable paramagnetic members which are separated by a gap which opens and closes as the members move relatively away from and toward each other. One of the paramagnetic members is provided with electrical windings which, when energized, produce a magnetic field which will pull the members together and close the gaps between them. The windings are energized by means which causes an electrical current to flow through them to create a magnetomotive force, and control means are provided for gradually reducing the magnetomotive force while the gap is being closed by the field. Preferably, the windings associated with a particular paramagnetic member include a plurality of winding sections, and the control means is constructed and operated to energize simultaneously and deenergize sequentially the sections of windings. The control means preferably is a timer provided with a set of cams which rotate together at a constant angular velocity. A set of electrical switches are sequentially operated by the cams and are connected to respective sections of windings. A single rotary cam may be operatively engaged with switches associated with the windings of two different paramagnetic members.
In another sense, the invention pertains to a system which includes an axially aligned set of paramagnetic members which include a central paramagnetic member and a spaced pair of paramagnetic members which are spaced apart by a constant distance and are located on opposite sides of the central member. Two intermediate paramagnetic members are located where each lies between the central paramagnetic member and one of the spaced pair of members. The energizing means is operable in a first mode to produce movement in a first direction by creating magnetic attraction between one intermediate member, the central member and one of the spaced pair of members. The energizing means is operable in a second mode to produce movement in an opposite direction by creating magnetic attraction between the other intermediate member, the central member and the other one of the spaced pair of paramagnetic members.
In another sense, the invention relates to a set of aligned paramagnetic members which includes a driven paramagnetic member located between two stationary paramagnetic members. A first movable intermediate paramagnetic member is located between one stationary member and the driven member; and, a second movable intermediate paramagnetic member is located between the other stationary member and the driven member. The intermediate members are on opposite sides of the driven member. The energizing means associated with this apparatus is operable in a first mode to create magnetic attraction between the first intermediate member, the driven member and the first stationary member to move the driven member in a first direction. The energizing means is operable in a second mode to create magnetic attraction between the second intermediate member, the driven member and the second stationary member to move the driven member in a second direction which is opposite to the first direction. Means are provided for repeatedly shifting the energizing means between the first mode and the second mode to move the driven member alternately in the first and second directions.
Although the invention may take many forms, the presently preferred embodiments thereof are described in the following text and illustrated in the drawings.