Latching actuators

Claim 2

A latching solenoid actuator having a stationary member and a moving member adapted for motion between first and second orientations with respect to said stationary member, and a solenoid coil, said stationary member and said moving member forming a magnetic circuit and both being fabricated of magnetic materials exhibiting the magnetic characteristics of generally soft magnetic materials, said solenoid coil being disposed with respect to said magnetic circuit so as to cause a magnetizing force in said circuit in response to a current therethrough, said stationary member and said moving member being adapted to magnetically urge said moving member toward said first orientation with respect to said stationary member in response to the establishment of a magnetic field in said magnetic circuit, said stationary member and said moving member having cooperatively disposed surfaces so as to result in a minimum air gap in said circuit when in said first orientation, whereby the retentivity of said magnetic materials causes a high latching force in said first orientation whenever said moving member reaches said first orientation before the current in said coil causing said magnetizing force is terminated.

Claim 3

The latching actuator of claim 1 for linear actuation wherein said moving member has a generally flat first surface perpendicular to the direction of motion of said moving member and a generally cylindrical second surface parallel to said direction of motion, said stationary member having a first surface parallel to said first surface of said moving member and a second surface adjacent to and providing a clearance with respect to said second surface of said plunger, said first surfaces being in substantial contact when said moving member is in said first orientation.

Claim 4

The latching actuator of claim 2 wherein said second surfaces have areas which are much larger than said first areas.

Claim 5

The latching actuator of claim 1 for linear actuation wherein said moving member and said stationary member each have first and second areas substantially perpendicular to the direction of motion of said moving member, said magnetizing force causing a magnetic field to occur in the air gap between said first surfaces and in the air gap between said second surfaces, said first surfaces and said second surfaces being disposed so as to be in substantial contact when said actuator is in the latched position.

Claim 6

The latching actuator of claim 4 wherein the area of at least one pair of said first and second areas is substantially less than the cross-sectional area of said magnetic circuit in regions remote to said first and second areas.

Claim 7

The latching actuator of claim 1 further comprised of a means for selectively causing a momentary magnetizing current to flow in said coil for a time period at least as long as the time required for said moving member to move to said first orientation and a demagnetizing means for causing the substantial demagnetization of said magnetic circuit.

Claim 8

The latching actuator of claim 6 wherein said demagnetizing means is comprised of a second coil disposed with respect to said magnetic circuit so as to cause a demagnetizing force in said circuit in response to a current therethrough, and a means for selectively causing a demangetizing current in said demagnetizing means.

Claim 9

The latching actuator of claim 6 wherein said demagnetizing means comprises a means for selectively causing a predetermined current in said solenoid coil which is substantially less than and of opposite polarIty from said magnetizing current.

Claim 10

A solenoid actuator having a stationary member and a moving member adapted for motion between first and second orientations with respect to said stationary member, a solenoid coil having first and second leads, a switch and a current maintaining means, said stationary member and said moving member forming a magnetic circuit and both being fabricated of magnetic materials exhibiting the magnetic characteristics of generally soft magnetic materials, said solenoid coil being disposed with respect to said magnetic circuit so as to cause a magnetizing force in said circuit in response to a current therethrough, said stationary member and said moving member having cooperatively disposed surfaces so as to result in a minimum air gap when in said first orientation, and further being adapted to magnetically urge said moving member toward said first orientation with respect to said stationary member in response to the establishment of a magnetic field in said magnetic circuit, said switch being electrically coupled to said first solenoid coil lead and adapted to switch electrical coupling with said first solenoid coil lead between first and second actuator leads in response to motion between said stationary member and said moving member, said current maintaining means being a means for maintaining a substantial magnetizing current in said solenoid coil during the time of actuation of said moving member from said second orientation to said first orientation.

Claim 11

A solenoid actuator having a stationary member and a moving member adapted for motion between first and second orientations with respect to said stationary member, a solenoid coil having first and second leads, a switch and a current maintaining means, said stationary member and said moving member forming a magnetic circuit and both being fabricated of magnetic materials exhibiting the magnetic characteristics of generally soft magnetic materials, said solenoid coil being disposed with respect to said magnetic circuit so as to cause a magnetizing force in said circuit in response to a current therethrough, said stationary member and said moving member having cooperatively disposed surfaces so as to result in a minimum air gap when in said first orientation, and further being adapted to magnetically urge said moving member toward said first orientation with respect to said stationary member in response to the establishment of a magnetic field in said magnetic circuit, said switch being electrically coupled to said first solenoid coil lead and adapted to switch electrical coupling with said first solenoid coil lead between first and second actuator leads in response to motion between said stationary member and said moving member, said current maintaining means being a means for maintaining a substantial magnetizing current in said solenoid coil during the time of actuation of said moving member from said second orientation to said first orientation.

Claim 12

The solenoid actuator of claim 9 wherein said current maintaining means comprises said switch and its mechanical coupling to said stationary and said moving members, whereby switching of said switch is delayed during the motion of said moving member from said second orientation to said first orientation until said moving member comes to rest at said first orientation.

Claim 13

The solenoid actuator of claim 9 wherein said current maintaining means comprises a diode coupled between said first solenoid coil lead and said first actuator lead, whereby a magnetizing current may be caused to flow in said solenoid coil when said moving member is in said second orientation by applying power to said second actuator lead and said current may be substantially maintained through said diode during switching of said switch by the back EMF of said solenoid coil.

Claim 14

The latching actuator of claim 9 for linear actuation wherein said moving member has a generally flat first surface perpendicular to the direction of motion of said moving member and a generally cylindrical second surface parallel to said direction of motion, said stationary member having a first surface parallel to said first surface of said moving member and a second surface adjacent to and providing a clearance with respect to said second surface of said moving member, said first surfaces being in substantial contact when said moving member is in said first orientation.

Claim 15

The latching actuator of claim 12 wherein said second surfaces have areas which are much larger than said first areas.

Claim 16

The latching actuator of claim 9 for linear actuation wherein said moving member and said stationary member each have first and second areas substantially perpendicular to the direction of motion of said moving member, said magnetizing force causing a magnetic field to occur in the air gap between said first surfaces and in the air gap between said second surfaces, said first surfaces and said second surfaces being disposed so as to be in substantial contact when said actuator is in the latched position.

Claim 17

The latching actuator of claim 14 wherein the area of at least one pair of said first and second areas is substantially less than the cross-sectional area of said magnetic circuit in regions remote to said first and second areas.

Claim 18

The latching actuator of claim 9 further comprised of a demagnetizing means for causing the substantial demagnetization of said magnetic circuit.

Claim 19

A solenoid actuator having a statioNary member and a moving member adapted for motion between first and second orientations with respect to said stationary member, a solenoid coil having first and second leads, a switch and a current limiting means, said stationary member and said moving member forming a magnetic circuit and both being fabricated of magnetic materials exhibiting characteristics of generally soft magnetic materials, said solenoid coil being disposed with respect to said magnetic circuit so as to cause a magnetizing force in said circuit in response to a current therethrough, said stationary member and said moving member having cooperatively disposed surfaces so as to result in a predetermined air gap when in said first orientation, and further being adapted to magnetically urge said moving member toward said first orientation with respect to said stationary member in response to the establishment of a magnetic field in said magnetic circuit, said switch and said current limiting means being electrically coupled between said first solenoid coil lead and an actuator connection whereby substantially direct coupling between said actuator connection and said first solenoid coil lead is achieved when said switch is in a first position but said coupling is limited by said current limiting means when said switch is in a second position, said switch being adapted to switch to said second position as said moving member approaches said first position.

Claim 20

A solenoid actuator having a statioNary member and a moving member adapted for motion between first and second orientations with respect to said stationary member, a solenoid coil having first and second leads, a switch and a current limiting means, said stationary member and said moving member forming a magnetic circuit and both being fabricated of magnetic materials exhibiting characteristics of generally soft magnetic materials, said solenoid coil being disposed with respect to said magnetic circuit so as to cause a magnetizing force in said circuit in response to a current therethrough, said stationary member and said moving member having cooperatively disposed surfaces so as to result in a predetermined air gap when in said first orientation, and further being adapted to magnetically urge said moving member toward said first orientation with respect to said stationary member in response to the establishment of a magnetic field in said magnetic circuit, said switch and said current limiting means being electrically coupled between said first solenoid coil lead and an actuator connection whereby substantially direct coupling between said actuator connection and said first solenoid coil lead is achieved when said switch is in a first position but said coupling is limited by said current limiting means when said switch is in a second position, said switch being adapted to switch to said second position as said moving member approaches said first position.

Claim 21

The solenoid actuator of claim 17 whereby said current limiting means is a resistor and said switch is a single pole single throw switch, said switch and said resistor being coupled in parallel.

Claim 22

The actuator of claim 17 further comprised of a return means for returning said moving member to said second position, said return means having a predetermined return force when said moving member is in said first position which exceeds the force urging said moving member toward said first position due to the retentivity of said stationary and said moving member, and is less than the force urging said moving member toward said first position due to the combined effects of said retentivity and a magnetizing current in said solenoid coil limited by said current limiting means.