Patent GB-190506077-A (GB)
Title: Improvements in, and relating to, Apparatus for Indicating when the Trolley-standards of Electrically-driven Vehicles become "Alive" and for Guarding the Standards when in such a Condition.
Inventor: PRINGLE PERCIVAL JOHN
Filed: 1905-03-22
Granted: 1906-06-22
Abstract: 6077. Pringle, P. J. March 22. Signals, automaticalarm; signals, indicator or visible.-Relates to apparatus for indicating when the trolly - standards of electric tramcars &c. become " alive." An audible indication may continue until the entrance or entrances to the top of the car has or have been barricaded. The trolly - standard p, Fig. 1, is connected to earth h through the switch c and solenoid a, which, when energized, releases the lever b so that it acts as a visible indicator and at the same time closes the circuit of the bell 7. Figs. 3 and 5 show an elevation and transverse section respectively of one form of apparatus. The solenoid a, Fig. 5, has a core n, to the lower end of which is fixed an armature lever t, carrying at its upper end a wedgeshaped catch x normally engaging a member y on the lever b. When the solenoid is energized, it attracts the upper end of the lever t, thereby releasing the lever b, which falls from the position shown in Fig. 3 into the display position. At the same time, the stud 4 on the projection 2 of the lever b closes the contacts 5 in the bell circuit, the contacts 8 in the same circuit being normally closed by the part 9 on the member 11 of the switch. When the lever b has fallen, the switch c can be opened by the push 14, but the switch is normally locked by the projection 2. When the conductor is warned by the bell 7 that the standard p is " alive," he withdraws the trolly from the overhead wire, and removes the outside passengers, and then opens the switch c by means of the push 14, the projection 18 on the member 11 interlocking with the member y on the fallen lever b. The bell circuit is thus broken at the contacts 8 but the visual signal is retained. The trolly is then again connected to the overhead wire and the car again started. When the repairs are completed, the lever b is reset by hand, the spring 17 closing the switch c. In a modified construction, the lever b has a second catch device, which retains it in an intermediate or semi-danger position when the members x, y are disengaged, but allows it to fall to the danger position when the solenoid is again de-energized. Electric lamps may also be used as supplementary visual signals, and to prevent the resetting of the lever b being overlooked. In order to prevent passengers from getting on the outside of the car, each entrance thereto may be barricaded, and the arrangement may be such that the bell 7 continues ringing until all such barricades have been put into position. For this purpose, each barricade contains a contact in the bell circuit, which contact is broken only when the barricade is in position, When it is not desirable to remove the trolly from the overhead wire, the switch c may be combined with a second switch, arranged in such a way that the latter can only open after the opening of the other switch, though they may close simultaneously.