Patent GB-190720022-A (GB)
Title: Improvements in Bascule Bridges.
Inventor: SCHERZER ALBERT HENRY
Filed: 1907-09-07
Granted: 1908-02-27
Abstract: 20,022. Scherzer, A. H. Sept. 7. Bridges.-Relates to bascule bridges of the rolling-lift type. The rolling segments are attached to, and located in the planes of, the trusses. Rigidly attached to the trusses is a counterweight consisting of two vertical parts I, Fig. 1, arranged in the planes of the trusses and located between the upper ends of the rolling segments and rear extensions a<2> of the upper chords of the trusses, and an horizontal part I', Fig. 3, attached to and extending between the trusses. A movable counterweight I<2>, Fig. 3, is suspended from an horizontal shaft P between the sides of the fixed counterweight. Both fixed and movable counterweights are formed by filling metal casings with concrete. Pinions j engage with circular racks i<1> on the lower curved face of the movable counterweight, and are driven by a train of gear-wheels J<1> from an electric motor supported on the horizontal part of the fixed counterweight. The motor is provided with brake mechanism to limit the movement of the swinging counterweight, which hangs freely when the leaf is in a half-open position. Hydrostatic or pneumatic buffers K, Figs. 1, 3, and 4, are located at the front and rear ends of the leaf to lessen the shock on closing and opening the bridge. In the open position of the bridge leaf, a piston K<2> is at the bottom of the cylinder K<1>; on closing the bridge, a head K<4> attached to the piston-rod K<3> strikes against a cap block E<1> on the pier E, and the piston is driven into the cylinder, compressing the fluid therein, which can escape slowly through a check valve exit pipe k<3>, Fig. 4. In the case of the rear end of the bridge, the head on the piston-rod strikes against a fixed stop T, Fig. 1. The leaf, when closed, is locked by a bar L, Fig. 4, sliding into a socket piece L<1> attached to the pier-cap block. The locking-bar is thrust home by a system of levers m<1>, m<3>, N, N<1>, Fig. 4, and connected locking-rods M, M<1>, M<2>, Figs. 4 and 13, carried partly on the stationary approach and partly on the moving leaf. The locking-rods are automatically separated or engaged by a hook M<4>, Fig. 13, on the rod M' engaging an horizontallyarranged loop M<5>, Figs. 7 and 13, on the rod M. The hook M' is formed with shoulders m<5>, m<4> which engage the transverse member m<6>of the loop M<5>. The loop M<5> slides horizontally between guides in a block M<6>. A weighted detent M<7> can engage with the loop M<5> to prevent the rod M from moving rearwardly. A collar attached to the rod M and engaging with one of the bearings of the rod prevents the rod from moving inwardly. To open the leaf, the locking-bar is first drawn from the socket by means of the locking-rod, operated from some point on the bridge approach, and the counterweight P is then moved. As the leaf swings upwardly, a hooked detent L<2>, when clear of the socket piece L', falls over the pointed end of the locking-bar, and thus prevents any outward movement of the bar. On closing the bridge, the detent comes in contact with the socket piece, and is swung clear of the bar. The hook M<4> on the rod M' strikes against the detent M<7>, Fig. 13, thereby depressing it, and allowing the shoulders of the hook to engage with the member m<6> of the loop M<5>. The locking-rod then thrusts the locking-bar into its retaining-pocket. A compensating-device connecting the rods M', M<2> consists of two bell-crank levers O<1>, O<2>, Fig. 7, connected by a link. This device counteracts the tendency of endlong displacement of the locking-rods due to the weights of the rods, when the leaf is open, the device being situated at such a point that the rods M<1>, M' are of substantially equal weight. When used as a railway bridge, the rails on the moving leafs are brought into alinement with the rails on the stationary approach, by the engagement of the end of the swinging leaf with the inclined faces of guide-plates Q, Figs. 1 and 4, which are supported on the pier-cap block. The rails on the moving leaf are adjusted at both ends of the swinging leaf by allowing the rails to project beyond the floor structure, so as to overlap and bear on supports on the stationary approach. Bridging-bars S, Fig. 8, bolted to the rails P at the swinging end of the leaf, extend beyond the floor of the moving leaf, and the compound bar is guided into position by the engagement of the guide-plate R' with the inclined faces r, r. At the rear end of the leaf, the guide-plates have their flanges in position to engage the opposite margins of the base flanges of the rails. To prevent slipping when the segments roll, teeth g on the track girder fit into corresponding sockets in the rolling segments.