Patent GB-190812923-A (GB)
Title: Improved Point Shifting Arrangements for Electric Tramways and the like.
Inventor: TIERNEY JOSEPH PATRICK
Filed: 1908-06-17
Granted: 1909-04-22
Abstract: 12,923. Tierney, J. P., and Malone, J. June 17. Points and switches.-The track points on electric railways and tramways are operated in both directions by a single electro-magnet pivotally mounted. The core of the electro-magnet actuates the point tongues through mechanism, which, after each movement of the tongues, causes the electromagnet to turn or tilt on its pivot and assume a position in which the core can, when the electromagnet is again energized, act upon the mechanism to move the points in the opposite direction. The winding of the electro-magnet is connected with an electric contact in advance of the junction so as to be energized therefrom as described in Specifications No. 22,763, A.D. 1905, and No. 15,016, A.D. 1906. In the construction shown in Figs. 2 and 4, the electro-magnet is carried in a cast-iron casing 17 arranged to move in a vertical plane or knife-edge bearings 15 placed either at the sides or underneath. Placed above but in the same plane as the core 33 are two arms 31, 32 fixed on the shafts 19, 18 which extend parallel to the track rails and carry cranks 23 adapted to engage collars on the rod 24 connected to the point tongues. Levers 34, 35 are also fixed on the shafts 18, 19 so that as these shafts are oscillated one or other of the levers engages and tilts the tray 36 pivoted to the casing 17 and containing a rolling weight 37. Stops 39 limit the movement of the tray. When the electro-magnet is energized the core is raised and presses one or other of the arms 31, 32 into its raised position. This operation moves the points over and oscillates the other shaft so as to depress its arm 32 or 31 and cause its lever 35 or 34 to tilt the tray 36. The weight 37 then moves to the opposite end of the tray and, when the core falls, turns the electro-magnet casing on its knife-edges. The core is now in a position to engage the other arm for the reverse movement of the points when the electro-magnet is again energized. In a modification the rolling weight is dispensed with and the levers 34, 35 are connected to springs which are connected at their other ends to some part of the casing 17. During the operative stroke of the core one of these springs is put into tension which when the core is liberated serves to tilt the electro-magnet. In another form plate springs are attached directly to the shafts 18, 19 and arranged so that the casing is tilted by one or other of them pressing upon its upper part. Fig. 11 shows diagrammatically a modified arrangement for energizing the electro-magnet. The contact 4 is preferably of the construction described in Specification No. 15,016, A.D. 1906, and is in series relation with the car motors, while the contact 50 is in parallel. A switch M is connected to the casing 17 or to the points so as to be operated therefrom when the casing or the points are oscillated. The points are operated from the contact 4 if the motor switch on the cars is in its 'on' position and the points cannot again be operated from this contact until the car collector has passed over the contact. 50 and moved the points and switch M back into their initial position.