An electromagnetic actuator for a medical instrument including: a stator; and a movable element, at least partly composed of a paramagnetic and/or a ferromagnetic material, and which can be reversibly moved from a first to a second position by the application of a switchable magnetic field, wherein the stator and the movable element have annular distal and proximal pole shoes corresponding to each other, wherein the distal pole shoes and/or the proximal pole shoes of the stator and the movable element are aligned with each other in an overlapping manner in the first and/or the second position, and the distal pole shoes and/or the proximal pole shoes of the stator and the movable element have a structure in the circumferential direction on the surfaces of pole shoes facing each other, with the structures corresponding to each other.

An electromagnetic actuator for a medical instrument including: a stator; and a movable element, at least partly composed of a paramagnetic and/or a ferromagnetic material, and which can be reversibly moved from a first to a second position by the application of a switchable magnetic field, wherein the stator and the movable element have annular distal and proximal pole shoes corresponding to each other, wherein the distal pole shoes and/or the proximal pole shoes of the stator and the movable element are aligned with each other in an overlapping manner in the first and/or the second position, and the distal pole shoes and/or the proximal pole shoes of the stator and the movable element have a structure in the circumferential direction on the surfaces of pole shoes facing each other, with the structures corresponding to each other.

Systems and methods are disclosed herein that may be implemented to configure, provide and operate retractable key assemblies and/or key assemblies that present a variable key assembly depression force to a user. In one example, key assemblies may be provided that each employ one or more electro-permanent magnets (EPMs) together with permanent magnet and/or magnetically permeable (e.g., ferromagnetic) key assembly components to control key retraction and extension, and/or to control peak depression force (e.g., typing force) required to depress and displace a key assembly from an extended position to a lower position that causes the key assembly to produce a digital or analog output signal.

The DC operated polarized electromagnet includes a spool around which an excitation coil is wound and that has a central opening, a plunger having first and second armatures, fitted individually, an outer yoke enclosing opposing side faces of the spool so as to attract the first armature, an inner yoke arranged on the inner side of the outer yoke so as to attract the second armature, and permanent magnets arranged between the outer yoke and the inner yoke, and reduces magnetoresistance by setting the thickness of the outer yoke thicker than the thickness of the inner yoke so that convergent magnetic flux in the plunger is diverted into the outer yoke.

The DC operated polarized electromagnet includes a spool around which an excitation coil is wound and that has a central opening, a plunger having first and second armatures, fitted individually, an outer yoke enclosing opposing side faces of the spool so as to attract the first armature, an inner yoke arranged on the inner side of the outer yoke so as to attract the second armature, and permanent magnets arranged between the outer yoke and the inner yoke, and reduces magnetoresistance by setting the thickness of the outer yoke thicker than the thickness of the inner yoke so that convergent magnetic flux in the plunger is diverted into the outer yoke.

An electrical machine includes a stator and a rotor rotatably mounted in the stator. A spindle is guided through the electrical machine. At least one magnetic flux-conductive assembly which can be introduced into the electrical machine is provided. The magnetic flux-conductive assembly is disposed on the spindle in a linearly displaceable manner in order to vary a motor constant of the electrical machine as a result of a displacement into the electrical machine.

An electrical machine includes a stator and a rotor rotatably mounted in the stator. A spindle is guided through the electrical machine. At least one magnetic flux-conductive assembly which can be introduced into the electrical machine is provided. The magnetic flux-conductive assembly is disposed on the spindle in a linearly displaceable manner in order to vary a motor constant of the electrical machine as a result of a displacement into the electrical machine.

A electromagnetic camshaft adjuster comprising: an armature unit which can be moved relative to a pole core when a stationary coil unit is energized and which has an armature plunger; and a permanent magnet unit by means of which the armature unit is held in a rest position when the coil unit is not energized; and a spring element between the pole core and the armature unit to force the armature unit axially away from the pole core, the spring force of the spring element being chosen smaller than the holding force of the permanent magnet unit when the coil unit is not energized. The permanent magnet unit is stationarily arranged between a housing cover and the pole core, the armature plunger is rotationally arranged, and the spring element is supported on a part of the armature unit which is rotationally fixedly mounted.

A magnetic actuator, comprising a first magnet having a first magnetic axis and having a first magnetic field, a second magnet having a second magnetic axis and having a second magnetic field, the first and second magnets defining, at least in part, a magnetic assembly; and a coil actuator assembly at least partially disposed about the magnetic assembly, wherein the first and second magnetic fields collectively approximate a curve. A tilt platform assembly, comprising a support base: a tilt platform pivotally coupled to the support base: at least one coil actuator assembly, mounted to one of the support base or the tilt platform; and at least one magnet assembly mounted to the other of the support base or tilt platform, and being disposable within the at least one coil actuator assembly, the at least one magnetic assembly comprising at least two magnets having respective magnetic fields angularly offset from one another and that collectively approximate a curve.

Electromagnetic actuators capable of generating a symmetrical bidirectional force are disclosed. The electromagnetic actuators include a housing made of a ferromagnetic material and a shaft made of a magnetically inert material movable along an axis within the housing. In one type of actuator, captive permanent magnets are arranged on opposite interior end walls of the housing and an electromagnetic coil is mounted on a central portion of the shaft. The electromagnetic coil is capable of generating a force when energized that causes linear displacement of the shaft in either direction along its axis depending on the direction of current through the electromagnetic coil. In another type of actuator, captive electromagnetic coils are arranged on opposing inner end walls of the housing, and a permanent magnet is mounted on a central portion of the shaft. The electromagnetic coils are capable of generating a force when energized that causes linear displacement of the shaft in either direction along its axis depending on a direction of current through the electromagnetic coils.