Patent GB-190628112-A (GB)
Title: Improvements in Switch Controlling Mechanism for Electrical Installations
Filed: 1906-12-10
Granted: 1907-12-05
Abstract: 28,112. British Thomson-Houston Co., and Woodbridge, J. E. Dec. 10. Electric railways and tramways; switches.- Switch-operating mechanism for electric traction systems comprises duplicate sets of mechanism at opposite ends of a section, each set consisting of a line switch and an earthing-switch, so interlocked that the supply conductor cannot be connected to the line while either of the earthing-switches is closed. Connecting and clutching means are provided so that both line switches may be operated from either end of the section. A band-operated lever c mounted on a shaft b carried by a pedestal a is connected by a rod d and toggle mechanism w to the line switch. The lever c is provided with a locking-rod e adapted to engage a notch f in a second lever g mounted on the shaft b and linked to a connecting-rod h operated from a single cabinat the other end of the section. Located on the frame a adjacent to the lever c is a locking-mechanism k, which operates a bolt l to cause a lever m to engage a collar n on the lecking-rod e so as to raise it out of the notch f on the lever g. This prevents the closing of the line switch by means of the lever operated from the distant cabin. The operating - lever o of the earthing - switch is so arranged that, even if its locking-mechanism p is unlocked, it would be impossible to close the switch by reason of the switches fouling. The locking- mechanism p for this lever may be the same as the locking-mechanism k, a bolt q engaging a projection or entering a slot in the lever o, which is adapted when the earthing-switch is closed, as in Fig. 1, to engage a lever r, Fig. 2, the other end of which engages a collar s on the locking-rod e, thereby lifting the rod out of engagement with the notch f on the lever g and so preventing the line switch from being closed from the distant cabin. If in the position shown in Fig. 3 the lever in the distant cabin is operated, then the lever g will be moved over until the projection on the locking-rod e rides up the cam surface into the notch f, after which the main switch can be opened from the distant cabin. Additional locking-means are provided when the section is earthed, consisting of a rod t, Fig. 3, adapted to be passed through apertures in the levers c, o, a padlock u being secured to the end of said rod to prevent its withdrawal. The toggle-levers w of the free-handle type are arranged to'be tripped by an overload relay v for opening the line switch on an overload, an alarm-bell circuit being c'osed at the same time through contacts x. Two keys only are provided, each of-which fits the lock k at one end of the section and the lock p at the other end of the section. In operation, when a section bas been disconnected and earthed in order to repair faults, and it is desired to again connect it to the supply, both keys are in the locks p at the ends of the section and cannot be withdrawn until the levers o have been moved to the open position and locked. The keys are then taken to the opposite ends of the section and the levers c unlocked and moved to the closed position and locked. The keys cannot then be withdrawn until the levers c are locked in their open positions. The key of the padlock u is in charge of the person in charge of the section.