Linear actuator

DETAILED DESCRIPTION The above object as well as other objects not specifically enumerated are achieved by an improved structure for a linear actuator in which the rotary motion from a motor is converted to rotary motion of a lead screw by use of a worm gear drive train.
In turn, the rotary motion of the lead screw is converted to linear motion of an extension tube by use of a nut which is threadedly mounted on the lead screw.
The linear actuator includes a motor having a rotatable output shaft, and the lead screw has a forward end and a rear end.
A worm gear drive train connected between the motor output shaft and the lead screw converts the rotary motion of the motor output shaft into rotary motion of the lead screw.
An extension tube assembly is mounted at the forward end of the lead screw for movement axially of the lead screw and for engaging the workpiece or device to be moved linearly.
The extension tube assembly includes an extension tube concentrically disposed around the forward end of the lead screw.
The extension tube has a forward end for contacting a device requiring linear motion, and a rear end.
A nut is connected to the rear end of the extension tube and is threadedly mounted on the lead screw so that rotation of the lead screw moves the nut and the extension tube assembly axially along the lead screw.
A mounting adapter is positioned at the rear end of the lead screw for rotatably mounting the lead screw.
The mounting adapter also attaches the linear actuator to the support structure, such as a frame or machine.
The linear actuator preferably includes a housing to cover the linear actuator for protection from dirt and for maintaining lubrication.
The housing is mounted on the mounting adapter, and substantially all of the axial forces along the lead screw are transmitted through the mounting adapter and not through the housing.
All the large axial and radial forces are transmitted through and applied to the lead screw, the extension tube assembly, and the mounting adapter