Patent GB-190320219-A (GB)
Title: Improvements in or relating to Surface Contact & like Systems of Electric Traction and Apparatus therefor.
Inventor: BOULT WILFRID SWANWICK
Filed: 1903-09-19
Granted: 1904-08-04
Abstract: 20,219. Boult, W. S., and Boult, C. R. Sept. 19. Electric railways a n d tramways. - Relates to surfacecontact systems of electric traction such as that described in Specification No. 27,476, A.D. 1902, comprising conductors on the track, which are alive only when the car is over them, and the switches for which are controlled by polarized relays operated by magnets on the car, and comprises a system of connections, a fault indicator, and constructions and settings of the electromagnetic switch and polarized relays. The conductors are in the form of short rails A, the relative spacing of the conductors A and collectors K and the relative length of the conductors being such, that the rearmost collector does not leave a conductor till the foremost collector is on the next conductor. Each conductor is connected to the main J<1> through an electromagnetic switch G<4>, controlled by a relay F operated by magnets D on the car. The coils of the switch are in series in a line H, and one or the other is short-circuited according to the position taken by the relay. The electromagnetic switch, Fig. 3, comprises two horseshoe magnets M, M' (corresponding to the two coils), the upper cores of which are continuous, which in the gap between their lower cores the flat armature M<6> can oscillate. The armature M<6> is connected to a bar 0 (corresponding to the switch G<4>), which makes contact at O<2> with mercury in a cup P, and is formed with rods O<3> with porcelain extensions adapted to slide through a box R containing pellets R' of conducting-material and making contact at R<4> with mercury in a cup P<1>. The mercury in the cup P is connected to the main J<1> which runs through a trough on the outside of the casing N<1>, and the mercury in the cup P' is connected by a cable J<5> to the rail A. The magnets M, M<1> may be connected by mercury contacts at M<10> to the line H and to the relay. Thus the whole switch can be readily lifted out of its casing N' after taking off the cover N<2>. Fig. 8 shows a horizontal section, and Fig. 9 a transverse section of the relay. It comprises iron bars S having horse-shoe extensions S' secured within a brass casing T to an insulating-block U on which a polarized needle is pivoted. A flange T<3> at the bottom of the casing T rests in an oil groove T<4> in a fixed bottom-piece T<5> carrying mercury caps into which dip rods U<8> connected to the needle and the needle contacts U<7>, U<6>. Fig. 12 shows the setting of the relay. It is held down by an iron bolt C<4> passed through an iron block C' on the surface and engaging one of the bars S. The other bar S rests on an iron bar C<2> on which rests an iron block C on the other side of the rail A. The magnetic lines of force produced by the magnets D are thus caused to pass through the relay. The relay is readily lifted out after simply removing the bolt C<4>. The fault indicator consists of a trailing contact L connected through a high resistance L<1> and relay L<2> to the return conductor. The passage of a current due to a rail A being left alive operates the relay which then actuates a bell or other signal.