Electric actuators having internal load apparatus

A load apparatus for use with an electric actuator comprising:

• a drive gear operatively coupled to a drive system of the electric actuator, wherein the drive gear is to rotate in a first direction and a second direction, and wherein the drive gear is to move between a first rectilinear position and a second rectilinear position;
• a drive shaft operatively coupled to the drive gear, the drive shaft comprises a body having an aperture and an externally threaded portion to threadably engage the drive gear, the drive gear to cause the drive shaft to move in a first rectilinear direction when the drive gear rotates in the first direction and the drive gear to cause the drive shaft to move in a second rectilinear direction when the drive gear rotates in the second direction;
• a valve stem received by an aperture of the drive shaft, the drive shaft to move the valve stem between the first and second rectilinear positions;
• a fastener having a flanged portion, the fastener to threadably couple to a first portion of the valve stem adjacent a first end of the drive shaft to retain the drive shaft between the flanged portion and a shoulder of the valve stem adjacent a second end of the drive shaft;
• and
• a biasing element disposed between the drive gear and a seating surface such that when the drive gear rotates in the first direction and the drive shaft reaches an end of stroke position in the first rectilinear direction, the drive gear continues to rotate about the drive shaft in the first direction and moves axially relative to the drive shaft from the first rectilinear position to the second rectilinear position to deflect the biasing element.

A load apparatus for use with an electric actuator, comprising;

• means for driving a valve stem between a first position and a second position, the means for driving having means for slidably receiving the valve stem, the means for slidably receiving to extend through an entire length of the means for driving between a first end of the means for driving and a second end of the means for driving;
• first means for coupling a first end of the valve stem and the first end of the means for driving and second means for coupling a second end of the valve stem and the second end of the means for driving to prevent axial movement of the means for driving relative to the valve stem along a longitudinal axis of the valve stem;
• means for converting rotational motion of a drive system to rectilinear motion of the means for driving, the means for converting rotational motion to engage a threaded portion of the means for driving;
• means for providing a seat load to a fluid flow control member of a fluid valve coupled to the valve stem when the flow control member is in sealing engagement with a valve seat of the fluid valve and electric power to a motor is removed;
• and
• means for deflecting the means for providing a seat load, the means for deflecting to move at least a portion of the means for converting rotational motion axially relative to the means for driving toward the means for providing a seat load.

An electric actuator having an internal load apparatus-comprising:

• a drive system having a drive gear that includes a threaded aperture
• a drive shaft operatively coupled to the drive system, the drive shaft defines a body having a threaded portion and a longitudinal opening, the threaded portion to threadably engage the threaded aperture of the drive gear, wherein rotation of the drive system in a first rotational direction causes the drive shaft to move in a first rectilinear direction and rotation of the drive system in a second rotational direction causes the drive shaft to move in a second rectilinear direction opposite the first rectilinear direction;
• a valve stem slidably received through the longitudinal opening of the drive shaft, the valve stem coupled to a first end of the drive shaft and the valve stem includes a shoulder to be positioned adjacent an second end of the drive shaft;
• a biasing element operatively coupled to the drive shaft, at least a portion of the drive system to move axially toward the biasing element to deflect the biasing element when the drive shaft reaches an end of stroke position to provide a load to the drive shaft when electric power to the electric actuator is removed;
• and
• a fastener to capture or retain the drive shaft between the shoulder of the valve stem and the fastener to prevent axial movement of the valve stem relative to the drive shaft along a longitudinal axis of the longitudinal opening, wherein the fastener includes a nut having a flanged portion, the nut to threadably couple to the valve stem such that the flanged portion is to engage the first end of the drive shaft to capture or retain the drive shaft between the flanged portion and the shoulder of the valve stem.