Improvements in and relating to bascule bridges or lever draw-bridges

摘要

699,710. Bascule bridges. WERKSPOOR. N. V. Aug. 9, 1951 [Aug. 9, 1950], No. 18774/51. Class 20(i) A bascule bridge or a lever draw-bridge has an angularly movable span 1 and actuating mechanism comprising a runway 13 attached to a bridge part, and a roller 12 co-operating with the runway 13 and adapted to be angularly reciprocated about a fixed axis 11 with constant speed. the span being unbalanced when approaching its closed position and kept unbalanced when closed, by the roller 12, the bridge part being adapted to be swung about an axis 17, Fig. 1, or 12, Fig. 3, with respect to the span during the unbalancing operation. To open the bridge, an electric motor 5 acts through gearing 6, 7 8, 9 to rotate an arm 10 carrying the roller 12 about the axis 11, this action serving to depress the bridge part about the axis 17 until an auxiliary weight 16 on the part engages an abutment 18 on a counterweight 19 of the span 1. Simultaneously, pegs 20 on the bridge part enter the weight 19, and the span swings about an axis coincident with the axis 17. Conversely, on closing the bridge, bevelled faces 26 on the runway act on the roller 12 to allow the weight 16 to be raised above the abutment 18, and a pivot 25 on the roller 12 acts through a linkage 24, 23, 22, 21 to disengage the pegs 20 from the container 19. In a modification. Fig. 3, the auxiliary weight 16 is dispensed with, and the bridge part is permanently connected at 27 to the weight 19, a spring 29 being connected to the axis 17 which can move vertically in its bearings 28. When the span 1 approaches closed position the bridge part is raised as before due to co-operation of the roller 12 and surface 26, the spring 29 tending to pull the bridge part downwardly about an axis formed by the engagement of the roller 12 and surface 26. and hence an upwardly directed movement about this axis is auplied to the weight 19 which therefore unbalances the span 1.