Counterweight Frame: Rope Anchors Upper Crossmember Filler Retaining, 50% Load Equilibrium, CW Safety Gear EN 81-20 Cl. 9.8 and Separate Guide Rails

The counterweight frame (CW frame, counterweight cage, counterweight sling) is the structural assembly that houses and retains the counterweight filler weights and is suspended on the opposite side of the traction sheave from the car. Structural elements: (1) Upper cross-member — carries the rope anchors and upper guide shoes; (2) Uprights (stiles) — connect upper and lower cross-members; (3) Lower cross-member — holds the bottom row of fillers and provides the landing structure; (4) Filler retaining bars or cage plates — prevent individual filler plates from becoming loose or dislodged in operation (especially during safety gear arrest). Nominal counterweight weight: in EN 81-20, the counterweight is sized so that with the car at 50% of rated load, the system is in near-equilibrium — minimising traction motor torque requirements. Counterweight safety gear: EN 81-20 Cl. 9.8 requires a counterweight safety gear if the counterweight is located above a space accessible to persons (e.g. a parking area, maintenance area, or public space beneath the hoistway). The counterweight safety gear is identical in principle to the car safety gear, triggered by the counterweight overspeed governor rope. The counterweight frame is mounted on the same guide rails as the counterweight, which are separate from the car guide rails in most configurations.

View All Terms