Door operator system

1. An overhead door operator system for opening and closing an opening, comprising:

a door frame comprising a first frame section at a first side of the opening and a second frame section at a second side of the opening, each of the first frame section and the second frame section comprising a vertically extending part, a horizontally extending part and a bent interconnecting part;

a door arranged to be moved between an open (O) and a closed (C) position, the door being movably connected to the door frame, the door comprising a plurality of horizontal and interconnected sections;

a drive unit mounted on the door, the drive unit comprising at least one motor arranged to move the door from the closed position (C) to the open position; and

an elongated transmission member extending vertically along the first side of the opening,

wherein the drive unit further comprises a driven transmission member including a cogged wheel, sprocket, or ribbed wheel in driving connection with the motor, the driven transmission member being movably connected to the elongated transmission member and arranged to interplay with said elongated transmission member for driving the driven transmission member vertically along said elongated transmission member by means of the elongated transmission member at least partially wrapping around the cogged wheel, sprocket, or ribbed wheel of the driven transmission member,

the overhead door operator system further comprising a transmission mounting arrangement for attaching the elongated transmission member, said transmission mounting arrangement comprising a fixing point to which the elongated transmission member is mounted,

wherein the transmission mounting arrangement comprises a lever arm, wherein the fixing point is disposed at a first end of the lever arm, wherein the fixing point mounts a top end of the elongated transmission member with the first end of the lever arm and a second end of the lever arm is pivotally mounted to a fixed lever bracket of the transmission mounting arrangement, wherein the fixed lever bracket is mounted to the door frame or to a wall surrounding the opening such that the lever arm is in a first position when the door is in the open position (O) and a second position when the door is in a partially open position, wherein the fixing point is disposed vertically above the bent interconnecting part when the lever arm is in the first position.

2. The overhead door operator system according to claim 1 , wherein the lever arm is movable along an angle (a) relative the vertically extending part between the first and second position, wherein the angle (a) is between 10° and 45° relative a vertical plane in an outward direction facing away from the door when the lever arm is in the-second position and is between 10° and 110° relative said vertical plane in an inward direction towards the door when the lever arm is in the first position.

3. The overhead door operator system according to claim 1 , wherein the transmission mounting arrangement further comprises a dampening element arranged to bias the movement of the lever arm.

4. The overhead door operator system according to claim 1 , wherein the fixed lever bracket is provided with rotational stops arranged to prevent pivoting of the lever arm beyond the first and second position, respectively.

5. The overhead door operator system according to claim 1 , wherein the elongated transmission member is in the form of a bendable transmission member.

6. The overhead door operator system according to claim 1 , wherein the elongated transmission member is biased.

7. The overhead door operator system according to claim 6 , wherein a bottom end of the elongated transmission member is attached to a fix point by means of a spring arrangement.

8. The overhead door operator system according to claim 1 , wherein the drive unit is mounted to a bottommost section of the door.

9. The overhead door operator system according to claim 1 , wherein the fixing point is movable and attached to the elongated transmission member to move in response to a movement of the door, the fixing point being displaced away from the horizontally extending part when the door is moved from the open position (O) toward the closed position (C).