Patent GB-190519504-A (GB)
Title: Improvements in or relating to Trolley Poles for Electric Traction
Inventor: PRENTISS ANDREW LAFAYETTE
Filed: 1905-09-27
Granted: 1906-08-16
Abstract: 19,504. Prentiss, A. L. Sept. 27. Electric railways a n d tramways on the. overhead-conductor system. ' Collectors. - T roll y poles are maintained in the r a i s e d position by pneumatic pressure, and arranged so that the pole is lowered gradually on to the roof of the car when the trolly wheel jumps the wires. One arrangement of the apparatus is shown in Figs. 1, 2, and 3, Fig. 2 being an enlarged view of the lower end of the pole, showing the valve chamber and ports. The trolly pole D is forked at its lower end, and embraces the horizontal pressure cylinder B, to which it is connected by pivot pins f. Downward extensions h of the pole are connected to the cross-head G<1> on the piston-rod, by links h<1>, so that the pole is raised when the piston is moved rearwardly in the cylinder. The cylinder B swivels horizontally on the hollow vertical pivot a formed integral with the base-plate A, which is attached to the car. The reduced upper end of the pivot a is screwed, and passes through the annular ring b<1> on the cylinder, at which point an air-tight joint is formed between the pivot and cylinder by means of packing c, forced tightly against the ring b<1> by nuts c<1>, c<2>. At the top of the pivot a is formed an air chamber b<2>, which is closed at the top by a screw plug b<3> and supplied from a suitable source of pressure through the passages i, i<1>. A flexible tube. j connects the chamber b<2> to a valve chamber K preferably situated in the hollow trolly pole at the head of the fork. Two valves p, p<1> in the chamber K, mounted on the same spindle or on separate spindles placed end to end, can be operated to admit air to the cylinder B. from the pipe j by means of the tube l<1>, flexible tube m, and pipe n, or allow the air in the cylinder to escape through the pipes n, l<1>, n<2> into a cushioning-chamber U, which has a passage, controlled by a regulating- valve o<2>, communicating with the atmosphere. The valves are operated by a projection q on a sleeve q<1> surrounding the rod P, which is pivoted at its upper end to the trolly head. The latter is connected to the trolly pole by a pivot d<2> so that it can swivel in a vertical plane. The pressure of the trolly wheel against the wire depresses the trolly head, thereby raising the rod P and the sleeve q<1> against the action of a spring S, and thus raising the valves p, p<1> by means of the projection . q, and putting the cylinder into communication with the source of pressure. When the trolly wheel jumps the wire, the spring S forces down the rod P and sleeve q<1>, thus releasing the valves, which are then actuated by the air pressure to put the cylinder B into communication with the cushioning-chamber 0, and at the same time cut off the source of pressure. The pole B is lowered gently on to the top of the car as the air escapes from the chamber O. To raise the pole again, the trolly head is depressed by means of the operating-cord E. In the modified form of the apparatus shown in Figs. 4.and 5, the inlet valve p<4> is in the form of a hollow rotary plug, and is mounted on the air cylinder. Ports p<8>, p<9> admit the air directly from the air chamber b<4> to the cylinder. The port A<9>, next to the cylinder, is wider than the port p<8>, so that the cylinder remains open to the exhaust when the source of pressure is cut off. The exhaust air passes through the open end of the hollow valve p<4>, along the passage T', and through a similarly-shaped exhaust valve p<5> having ports t leading to the atmosphere. The exhaust valve p<5> is mounted in a casing T in the fork of the trolly pole, and is coupled to the inlet valve by crank arms u, u<1> and the connecting- rod u<2>. The valve mechanism is operated by the rod P<1>, leading to the trolly-head, in the manner -previously described.