GB190501224A - Improvements in and relating to Trolley Retrievers for Electric Tram Car and the like. - Google Patents

Abstract

1224. Earll, C. I. Jan. 21. Electric railways with overhead conductors. Collectors. - Relates to trolly retrievers or catchers, for tramcars and the like, of the type in which a spring drum is acted on by two springs, the stronger of which is normally out of action, but is brought into action when the trolly jumps the wire, and consists in improvements in the apparatus described in Specification No. 15,335, A.D. 1901, whereby the power spring can be rewound, locked, and released, the trolly rope being formed of two parts of different diameter and provided with an enlargement for handling purposes. Figs. 1, 2, and 3 show sections of the apparatus ; in Fig. 2, the power spring is wound up, while in Fig. 3, it is shown unwound. A casing 1, 2 is fitted with a central shaft 3 on which is fixed a disk 6 secured by its hub 7 to the tension spring 8, and a drum 9 for the trolly rope. The outer end of the power spring 11 is secured to the drum, and its inner end to the sleeve 15 of an intermediate disk or member 16. This member carries a main lock pawl 20, which may engage teeth 19 on the drum or teeth 24 on a ratchet-ring which is normally held stationary by the pawl 27. A hanging pawl 29 is pivoted on the pawl 20, and a second check pawl 44 is connected to it by a spring 47. The intermediate member 16 also carries a bell-crank pawl 36, 39, and a pawl 40 connected together by a spring 42. When the trolly jumps the wire, the' sudden unwinding of the drum throws the suspended pawl 29 outwards into engagement with the teeth 24, thus disengaging the pawl 20 and allowing the power spring to wind the cord on to the drum and pull down the trolly pole, the check pawl 44 preventing unwinding due to rebound of the trolly pole. The pawl 20 is moved into engagement with the teeth 24, and the intermediate member 16 is thus held stationary. A controlling - stop 38 on the spring 11 also releases the bell-crank pawl 36, 39, and allows the set pawl 40 to move outwards into gear with the ratchet-ring, thus enabling the main lock pawl 20 to fall back on to the teeth of the drum when tension on the drum is released. The power spring 11 is set or rewound by unwinding the rope from the drum, the spring being prevented from unwinding by the pawl 20. When the spring is completely wound, a stop 38 on it engages a projection on the bell-crank arm 36, and moves the pawl arm into engagement with the teeth 19, thus preventing any further winding movement of the drum, and, when tension is relaxed, causing the spring 42 to withdraw the pawl 40 from the ratchet-ring, the drum being then left under the action of the tension spring 8 only. The trolly rope is made with an enlarged portion or grip 146 to facilitate handling. The grip may be braided into the rope or applied by winding. The rope may be made of two parts of different diameter, the part of smaller diameter being that wound on the drum.