| 摘要 |
663,242. Doors. DE VRIES ROBBE & CO., N. V. April 4, 1949 [April 2, 1948], No. 9071/49. Class 20(iii) A tilting door 3 adapted to close an opening 1 in a wall 2 is suspended by a hinged arm 5 pivoted to the wall at a point 6 on a level with the centre of gravity Z of the door and to the door midway between the centre of gravity and the lower edge 4 which is guided by means of a roller in the plane of the door. A weight 10 is rigidly secured to an extension of the door panels to bring the centre of gravity to the point shown : the door is of lightweight construction, e.g. aluminium sheeting. The lower guiding point 4 may be above the bottom edge which in this case projects outside the opening as the door rises. |
