The use of a screw clamp requires care and professional skill.
Inexperienced workers must not use a screw clamp without proper supervision.
Before each use, check that the response pieces are intact and sufficiently sharp (sharpness, see Maintenance). Clean loose rust, snow, and ice from the lifting point.
Install the screw clamp so that there is a small gap between the base of the clamp and the edge of the plate. Tighten the screw with a rigid wrench, L=300-400 mm, moderately tight. For example, on a normal S355 (St52) plate, the screw is tightened another 1/5–1/4 turn (70°–90°) after the tip of the screw has touched the surface of the plate. Do not tighten any further, as this will cause unnecessary wear on the counterplates.
When lifting heavy loads, lift a little first and make sure that the straps remain attached. For consecutive lifts, check the attachment between lifts. When lifting long sheets, use two or more straps and lifting beams.
Keep the device clean and the screw lubricated. The screw should turn by hand. The counterpieces must be replaced when the brushes are worn down by more than 1 mm, and the screw head must be sharpened and hardened. A nut or screw that is too loose must also be replaced. The stop screw/screw of the counter piece is secured with locking glue so that the counter piece can rotate. If necessary, request additional information from the manufacturer.
The screw pair is inspected once a year. If any warping, breakage, cracks, or severe wear is detected, the device must be repaired or sent to the manufacturer for repair, or removed from use entirely. Any irregularities caused by flame cutting of the plate frame during manufacture do not pose a hazard.
The screw is test loaded with a straight pull, CRA 1 with a force of 1.5 tons and CRA 075 with a force of 1.2 tons. No permanent deformation or breakage of the screw or counterpiece may occur. We recommend testing every two or three years.
The device has a 12-month warranty from the date of purchase, covering raw material and manufacturing defects. The warranty covers damage caused to the device. The warranty does not cover indirect damage or damage caused by misuse or overloading.