| 摘要 |
An up and over door assembly is disclosed comprising a door (1) constructed of hinged horizontal panels (4) guided by inverted L-shaped tracks (not shown) between a vertical closed position and a raised open position in which the door panel lies horizonally above the door opening. Characteristically the lift mechanism comprises two pairs of preferably rodless piston and cylinder units (12,14), one pair (12) to lift and take the weight of the door initially, and the other pair (16) to pull it into the open position. |
