A friction stay has a base member for connection to a fixed window frame. A linkage is provided and mounted on the base member and including an arm which connects to an opening window leaf. The linkage includes a part pivotally mounted on a slider carried by the base member for sliding movement as the...http://www.google.com.hk/patents/US5255471?utm_source=gb-gplus-share專利 US5255471 - Friction stays
