Apparatus for spring-assisted pivoting of a liftgate or door, and method for producing such apparatus

An apparatus for spring-assisted pivoting of a liftgate or door against gravity between a closed position and an open position, comprising:

• a tracker comprising a support bracket and a control cam;
• a length-adjustable lever guided in the control cam of the tracker;
• a coupling rod configured for translatory movement and operatively connected to the length-adjustable lever, said coupling rod configured to rotationally move a hinged lever associated with the liftgate or door;
• a torsion bar spring system having torsion bar springs arranged in parallel in a meander pattern and connected with one another in fixed rotative engagement;
• wherein a first outer torsion bar spring of the torsion bar spring system is constructed as a bearing-torsion bar spring and a second outer torsion bar spring of the torsion bar spring system is constructed as a lever-torsion bar spring which is connected in fixed rotative engagement with the length-adjustable lever, with both the first and the second outer torsion bar spring being supported in the support bracket of the tracker;
• and
• an adjusting device connected in fixed rotative engagement with the bearing-torsion bar spring and variably lockable relative to the support bracket.