One or two counter-weights which are connected to the lifting door using Timing-Belt Reverse Units and Timing Belts (Section 8.2 Mechanical Drive Elements) compensate for the weight of the door. The lifting door and counter-weights are guided in the grooves of the Stand Profiles by means of Guide Sets.
In addition, the Guide Sets connect the Timing Belt to the lifting door and counter-weight. As a rule, four Lifting Door Guide Sets are required for the lifting door and two for each counter- weight. The size of the counter-weight is determined by the weight of the lifting door. Whether one or two counter-weights are installed depends on the door weight and the ratio between the door width and door height, i.e. the aspect ratio.
Any suitable mass can be used as a counter-weight, (for example square steel bar or filled conduit elements). The counter-weights are screw attached to the Lifting-Door Guide Set which guides them along the profile groove.