Linear actuator
First Claim
Patent Images
1. An actuator, comprising:
- an electric motor comprising stator windings;
an elongate rotor, the rotor having an upper internally threaded portion and a lower internally threaded portion;
a first screw that extends along a longitudinal axis of the actuator, the first screw having a first externally threaded portion to operatively engage the upper internally threaded portion of the rotor;
a second screw that extends along the longitudinal axis of the actuator and is configured to move along the longitudinal axis relative to the motor, the second screw having a second externally threaded portion to operatively engage the lower internally threaded portion of the rotor, the first and second screws extending from opposite sides of the motor; and
an elongate magnet operatively coupled to the rotor and radially interposed between the first and second screws and the motor;
wherein the motor is disposed circumferentially about at least a portion of the rotor and first and second screws, the motor configured to axially displace one or both of the first and second screws via the magnet.
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Accused Products
Abstract
Linear actuators that allow for improved self-locking properties without sacrificing axial response are provided. A linear actuator can have two screws extending from opposite ends of the actuator. The screws are joined by and threadably coupled to an elongate rotating nut. An elongate magnet is disposed around and coupled to the nut, and a stator including coils surrounds the magnet and nut. The magnet and nut are not axially fixed with respect to the stator. Rotation of the nut causes axial displacement of both screws, causing the screws to move closer together or farther apart. A pitch of the screw threads can be selected to enhance self-locking properties.
226 Citations
16 Claims
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1. An actuator, comprising:
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an electric motor comprising stator windings; an elongate rotor, the rotor having an upper internally threaded portion and a lower internally threaded portion; a first screw that extends along a longitudinal axis of the actuator, the first screw having a first externally threaded portion to operatively engage the upper internally threaded portion of the rotor; a second screw that extends along the longitudinal axis of the actuator and is configured to move along the longitudinal axis relative to the motor, the second screw having a second externally threaded portion to operatively engage the lower internally threaded portion of the rotor, the first and second screws extending from opposite sides of the motor; and an elongate magnet operatively coupled to the rotor and radially interposed between the first and second screws and the motor; wherein the motor is disposed circumferentially about at least a portion of the rotor and first and second screws, the motor configured to axially displace one or both of the first and second screws via the magnet. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A device configured to be attached to a limb, comprising:
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a first portion; a second portion, the first and second portions pivotable relative to each other to simulate movement of a natural human joint; and an actuator comprising; an electric motor comprising stator windings; an elongate rotor, the rotor having an upper internally threaded portion and a lower internally threaded portion; a first screw that extends along a longitudinal axis of the actuator, the first screw having a first externally threaded portion to operatively engage the upper internally threaded portion of the rotor; a second screw that extends along the longitudinal axis of the actuator and is configured to move along the longitudinal axis relative to the motor, the second screw having a second externally threaded portion to operatively engage the lower internally threaded portion of the rotor, the first and second screws extending from opposite sides of the motor; and an elongate magnet operatively coupled to the rotor and radially interposed between the first and second screws and the motor, wherein the magnet is not axially fixed with respect to the motor; wherein the motor is disposed circumferentially about at least a portion of the rotor and first and second screws, the motor configured to axially displace one or both of the first and second screws and the rotor via the magnet to adjust an angle between the first portion and the second portion. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification