Drive arrangement for raisable and lowerable port construction

摘要

The necessary force for exposing an opening at the bottom and at the top varies with the size of the opening. A counterweight arrangement (11) acts with an adjusted force in the port lower closed position and is variable with the size of the opening. Two wheels (14,15) forming part of the counterweight arrangement have a conical shape. A line is arranged so that during opening of the port it has a variable radius and an altered torque and vice versa. The counterweight arrangement uses a screw spring (17) for creating in a torque for a drum (14). The conicity for the drums (6,6',14,15) used can also be adjusted in order to compensate for force and torque variations from the screw spring.