Patent GB-190703008-A (GB)
Title: Improvements in and connected with Guards or Fenders for Electric Tram-cars.
Inventor: LHOTTA CARL
Filed: 1907-02-06
Granted: 1907-07-04
Abstract: 3008. Lhotta, C., Lhotta, T., and Lhotta, E. Feb. 6. Electric locomotives and motorvehicles.-A. fender for electric tramcars is arranged to break the driving- circuit and close a braking-circuit when impact occurs, and is automatically extended at such a distance from the car that the car is brought to rest before reaching the obstruction, whatever be its speed at the time of collision. The front fender wall 1, Figs. and 2, can be 'pressed towards the back wall 2 against the action of springs, both walls being perforated at 7 for the car buffer and carried by spring- pressed rods 8 in rods 4. The rods 4 are supported on wheels 12 and are reciprocated on rollers 25 by the arrangements shown in Fig. 5. The car axle carries a gear-wheel 19 from which a governor 31 is driven by a flexible shaft 32. The governor actuates a double contact 35, 36, which, in conjunction with contacts 40,41 and the connexions shown, energizes one or other of the two magnets 29, 30, according as the car speed falls or rises, and so rocks a lever 18 which carries two wheels 16, 17 geared together and adapted to gear with the wheel 19 when the lever is rocked. The wheel 16 is connected by a flexible shaft 20 to a milled wheel 21 which bears on the fender rod 4 and is carried by the armature of the magnet 23, the circuit of which is completed through a contact 58, 60 between the fender walls. Motion of the feeder rods is governed by a brake 51 on the armature of a magnet 53, which is employed to oppose a hold-off spring and which is energized through a contact 54 on the rod 18 as long-as the latter is horizontal, that is while the car runs at normal speed. If the speed of the car rises, the contact 36, 41 is closed and the magnet 30 is energized. The arm 18 is accordingly rocked so as to release: the brake 51 and throw the wheels 17, 19 into gear to make the wheel 21 extend the fender. Simultaneously, the flexible shaft 46, which connects the wheel 17 and the. screw 45, is rotated so that the nut 44 and contacts 40, 41 are raised. Further rise of the governor extends the fender until it reaches the position predetermined for the given speed. If the car speed falls, the contact 40, 35 causes the lever to rock the other way and throw the wheel 16 into gear to retract the fender. When the car is at rest, the fender is drawn in close so that no obstruction to traffic occurs. A reversing-switch 75 enables the car to be operated in the opposite direction, and a switch 76 in the governor line 39 enables the mechanism to be put out of action, as for shunting. The car braking is effected by contacts 63, 68 on the fender, the opening of the contacts 63, on collision, cuts off the line supply to the motors 65, and the closure of the contact 68 causes the reversed motors to generate through rheostats I, II ... VI. The resistance is automatically increased in proportion to the extension of the fender by means of a wheel 24, which is driven by the fender rod 4 and is coupled by a flexible shaft 73 to the screw 72 which carries' the contact-finger 74 of the rheostat As the fender is retracted, the resistance is thus gradually cut out' independently of the driver. A switch 77 and spare line 78 enable the supply to the motors to be restored should the line 66 be destroyed by collision. In an alternative arrangement, the rods 4 are used as conduits for conductors which carry the small currents of a relay, which is so connected in circuit with the motors and the controller 64 that fracture of the frame due to a side collision will instantly cause the motors to brake.