Closers or openers for wings, not otherwise provided for in this subclass spring-actuated {, e.g. for horizontally sliding wings } for swinging wings {, e.g. counterbalance with a coil spring perpendicular to the pivot axis with a compression spring}
Closers or openers for wings, not otherwise provided for in this subclass spring-actuated {, e.g. for horizontally sliding wings } for swinging wings {, e.g. counterbalance with a coil spring perpendicular to the pivot axis with a compression spring}