A solenoid device includes two electromagnetic coils, two stationary cores, two plungers and a yoke that surrounds the two electromagnetic coils. When a first electromagnetic coil is energized, magnetic flux flows through a first magnetic circuit that includes the first stationary core. When the two electromagnetic coils are energized, magnetic flux of the first electromagnetic coil flows through the first magnetic circuit, and magnetic flux of the second electromagnetic coil flows through a second magnetic circuit that includes a second stationary core. When energization of the first electromagnetic coil is stopped while maintaining energization of the second electromagnetic coil, the magnetic flux of the second electromagnetic coil continues to flow through the second magnetic circuit and a third magnetic circuit that includes the two stationary cores. A magnetism limiting portion is disposed in a portion of the second magnetic circuit that does not overlap the third magnetic circuit.

An example solenoid tube (104) includes: a first cylindrical cavity portion (302), wherein the solenoid tube has a unitary construction, such that the solenoid tube is formed as a single component, wherein the solenoid tube is hollow, wherein an inner diameter of the solenoid tube varies along a length of the solenoid tube to form various cavity portions of varying diameters, and wherein the first cylindrical cavity portion has a first diameter (DI); a second cylindrical cavity portion (304) having a second diameter (D2), wherein the second diameter is greater than the first diameter; and a third cylindrical cavity portion (306) having a third diameter (D3), wherein the third diameter is smaller than the first diameter and smaller than the second diameter, such that a step (312) is formed at a transition from the second cylindrical cavity portion to the third cylindrical cavity portion.

An electronic device may include an electronic circuit, a heat sink thermally coupled to the electronic circuit, and spaced apart cooling fins extending from the heat sink. Each cooling fin includes a circuit board and a cooling device mounted thereon. The cooling device may have a conductive trace layer on the circuit board defining an electromagnet, a mounting member extending upwardly from the circuit board, a fan blade coupled to an upper end of the mounting member to be movable in a rocking motion about an axis defined by the mounting member, and a permanent magnet carried by the fan blade and responsive to the electromagnet.

A downhole magnetic clamping system for a tool is provided. The clamping system may include a first permanent magnet, and a yoke, movably positioned next to the first permanent magnet and movable to at least two positions, a first position in which a magnetic attraction force produced by the first permanent magnet on structures exterior to the tool is reduced relative to a second position. In addition, the clamping system may further include a non-linear resilient member applying a resilient force to the yoke in the direction of the second position. Further, the clamping system may include an electro-magnetic coil, operable in a first and second direction to initiate movement of the yoke between the first position and the second position.

A downhole magnetic clamping system for a tool is provided. The clamping system may include a first permanent magnet, and a yoke, movably positioned next to the first permanent magnet and movable to at least two positions, a first position in which a magnetic attraction force produced by the first permanent magnet on structures exterior to the tool is reduced relative to a second position. In addition, the clamping system may further include a non-linear resilient member applying a resilient force to the yoke in the direction of the second position. Further, the clamping system may include an electro-magnetic coil, operable in a first and second direction to initiate movement of the yoke between the first position and the second position.

In a main magnetic circuit, first pulling force generated based on a first component of the magnetic flux flowing through the main magnetic path pulls a movable core in a reciprocation direction of the movable core. The first pulling force increases with a reduction of a dimension of the gap. In an auxiliary magnetic circuit, second pulling force generated based on the second component of the magnetic flux flowing through the auxiliary magnetic path pulls the movable core in the reciprocation direction of the movable core. In the auxiliary magnetic circuit, the second pulling force with the dimension of the gap being within a first range is changed to be higher than the second pulling force with the dimension of the gap being within a second range, the second range being smaller than the first range.

A vapor delivery needle is provided that may include any of a number of features. One feature of the energy delivery probe is that it can apply condensable vapor energy to tissue, such as a prostrate, to shrink, damage, denaturate the prostate. In some embodiments, the vapor delivery needle can be advanced a predetermined distance into the prostate with a solenoid actuation mechanism. Methods associated with use of the energy delivery probe are also covered.

A vapor delivery needle is provided that may include any of a number of features. One feature of the energy delivery probe is that it can apply condensable vapor energy to tissue, such as a prostrate, to shrink, damage, denaturate the prostate. In some embodiments, the vapor delivery needle can be advanced a predetermined distance into the prostate with a solenoid actuation mechanism. Methods associated with use of the energy delivery probe are also covered.

An electromagnetic positioning device (1), having a stationary spool unit (9), having a moveably guided anchor (2), which forms a positioning section (14) and which can be axially displaced along a displacement axis (V) in response to supplying the spool unit (9) with current, as well as having a one-part cup-shaped yoke-core element (3), which receives the anchor (2) and which includes a core section (5) as well as a yoke section (6) and which has a yoke-core bottom (4) extending perpendicular to the displacement axis (V) and a yoke-core sheath extending perpendicular to the yoke-core bottom (4) along the displacement axis (V), a longitudinally cut transition area (8) reduced in thickness and arranged between the core section (5) and the yoke section (6) being realized in the yoke-core sheath. It is intended that a guide pin (17) for the anchor (2) is fixed, preferably pressed in, in a, preferably centric, guide pin recess (18) in the yoke-core bottom (4) and protrudes axially into a, preferably centric, guide opening (13) of the anchor (2) and can be displaced relative to the anchor (2) during its displacement movement.

Presented are a single coil apparatus and a method of forming. An exemplary apparatus includes solenoid assembly. The solenoid assembly includes a core tube extending along a longitudinal axis. The solenoid assembly further includes a first magnet and a second magnet located outside the core tube, the first magnet spaced along the longitudinal axis from the second magnet, and an excitation coil disposed radially outward of the first magnet and the second magnet.