Falling doors catch no fingers

Tom Shelley reports on a simple mechanical system that ensures sash windows and their modern analogues cannot crush fingers

Falling vertical sash windows have long been a hazard to fingers, but a system from German machine frame builders, item, overcomes all hazards with simple mechanics. The Ultra-Safe Lifting Door Set has a counterbalanced weight running on the inside in a conduit. The door and weight are connected by a chain. In the event of the chain failing or becoming detached from the window/door, spring loaded, serrated cams on both sides engage with the frame. These are normally kept retracted by the tension in the chain. The system is not dissimilar to that used on many lifts. The company also offers the option of a sprocket drive to move the chain and lift and lower the window/door mechanically. The completely modular item system comes with all kinds of ingenious fastenings, mountings, castors, hinges, locks, feet, label holders and other accessories, which are constantly being added to and improved. Distributors in the UK are Machine Building Systems in Ripley. Machine Building Systems