Motorized adjustable back support for recliner

1. A motorized adjustable back support for a recliner chair comprising:

a back frame with two side parts and an upper and lower part;

a backrest covering the frame and shaped to support a human back;

a motor;

means for transforming the power of the motor to a rotational movement of a horizontal rotation bar rotationally connected to the frame; and

two adjustment arms, each of said two adjustment arms being fixed on each side of the rotation bar close to the respective side parts of the frame, wherein the adjustments arms have a flexible elongate unit stretching between respective outer ends thereof, and wherein the adjustment arms can move the flexible elongate unit from a neutral to an extended position, corresponding to a rotation of the rotation bar,

wherein the flexible elongate unit is rotationally connected to the end of each adjustment arm,

wherein the backrest comprises an incision, which starts near a rear bottom corner of the backrest over at least a partial width of the backrest accommodating the adjustment arms and the incision then extends upward into the backrest in such a way that the flexible elongate unit can be positioned where the lower back of a user is expected to be, and

wherein the incision is lined with a wear resistant, low friction material.

2. The back support according to claim 1 , wherein the back frame is made of one of: metal tubulars, metal profiles, wood, a plastic product and fibers.

3. The back support according to claim 1 , wherein the cover of the backrest is wrapped around two separate parts divided by the incision.

4. The back support according to claim 1 , wherein the means for transforming the power of the motor to a rotational movement of a horizontal rotation bar is an extendable rod connected to the motor, which is mounted on the lower part of the back frame, wherein the extendable rod acts on a pivot arm fixedly connected to the rotation bar.

5. The back support according to claim 1 , wherein the backrest is made out of one or a combination of: polyurethane foam, latex foam, rubber foam, felt, wool or fibers.

6. The back support according to claim 1 , wherein the flexible elongate unit is a serpentine spring.

7. The back support according to claim 6 , wherein the serpentine spring is connected to the respective ends of the adjustment arms by means of a bolt going through a hole at the end of the adjustment arms, wherein the bolt is inserted through the hole from the outside relative to the center of the chair and has a hole through which the serpentine spring is inserted, thus holding the serpentine spring and bolts in tension between the adjustable arms, and wherein the serpentine spring is stabilized against movement in the hole of the bolt by a clip for holding the serpentine spring in a fixed rotatable position.

8. The back support according to claim 7 , wherein the clip holds the serpentine spring in a fixed rotatable position with a rotational axis going through the longitudinal centerline of the serpentine spring, wherein the serpentine spring is inserted through a hole in the bolt such that the centerline of the serpentine spring, the centerline of the bolt and the rotational axis coincide, wherein the clip comprises:

an upper section comprising a groove corresponding to the imprint of the bolt and at least a part of a turn on at least one side of the centerline of the serpentine spring;

a lower section comprising a similar mirroring groove; and

means for connecting the two sections in a locking grip,

wherein the imprint of the bolt in the groove has an additional depth to allow the serpentine spring to rotate in the hole in the bolt.