Anti-pinch electric linear actuator for electric adjustable furniture

1 . An anti-pinch electric linear actuator for the movable components of adjustable furniture, the anti-pinch electric linear actuator comprising:

an outer tube;

an inner tube extending into the outer tube in a way that the inner tube has an inner end located inside the outer tube, and an outer end located outside the outer tube;

a lead screw extending inside the outer tube and the inner tube;

a nut screwed onto the lead screw and located inside the outer tube, the nut having an abutment portion, which the inner end of the inner tube can contact the abutment portion and the inner end of the inner tube can separate from the abutment portion;

a motor to drive the nut, said motor mounted in the outer tube; and

a sensing unit disposed to the outer tube, the inner tube, or the nut for detecting whether the abutment portion of the nut is in contact with the inner end of the inner tube; and

wherein the inner tube of the linear actuator will move when the abutment portion of the nut is in contact with the inner end of the inner tube, but will not move when the abutment portion of the nut is not in contact with the inner end of the inner tube.

2 . The anti-pinch electric linear actuator of claim 1 :

wherein the sensing unit comprises two conductive wires disposed on the inner tube;

each of the two conductive wires has a contact end located at the inner end of the inner tube; when the two contact ends of the two conductive wires are in contact with the abutment portion of the nut, the two conductive wires are electrically connected with each other, but when the abutment portion of the nut is not in contact with the inner end of the inner tube the two conductive wires are not electronically connected with each other.

3 . The anti-pinch electric linear actuator of claim 2 , wherein the abutment portion of the nut is a conductive gasket.

4 . The anti-pinch electric linear actuator of claim 2 ;

wherein when the nut is driven by the lead screw to move outward, the abutment portion pushes the inner tube to extend outward;

wherein when the nut is driven by the lead screw to move inward and the inner tube receives an axially external force, the inner tube abuts against the abutment portion and moves inward along with the nut;

wherein when the nut is driven by the lead screw to move inward and the inner tube does not receive the axially external force, the inner tube stays in place and disengages from the abutment portion of the nut, and the electric connection of the sensing unit is broken thereby signaling the nut to stop the movement of the actuator.

5 . The anti-pinch electric linear actuator of claim 4 wherein said outer tube is attached to a base frame of a bed and wherein said outer end of said inner tube is attached to a movable component of the bed, whereby the anti-pinch electric linear actuator moves the movable component of the bed, and wherein further if a foreign object is placed between the moveable component of the bed and the base frame of the bed, the foreign object prevents the movable component of producing the axially external force and causes the inner tube to disengage from the abutment portion of the nut and stop the movement of the actuator.

6 . The anti-pinch electric linear actuator of claim 1 , wherein the sensing unit comprises a limit switch disposed at the inner end of the inner tube or at the abutment portion of the nut.

7 . The anti-pinch electric linear actuator of claim 1 , wherein the sensing unit comprises an optical sensing device or a magnetic reed switch.