A ladder-like grate for use in drainage ducts, which grate includes a main surface portion and opposed, upright longitudinal edges extending along respective longitudinal sides of the main surface portion, is produced from two sheet metal components at least one of which is provided with slits and each...http://www.google.com.au/patents/USRE32248?utm_source=gb-gplus-sharePatent USRE32248 - Grate for drainage ducts
