Patent GB-190301651-A (GB)
Title: Improvements in and Appertaining to Tramway Points or the like.
Inventor: MCKNIGHT WILLIAM ALPHONSUS
Filed: 1903-01-23
Granted: 1904-01-14
Abstract: 1651. McKnight, W. A. Jan. 23. Points and switches.- Relates to mechanism for controlling tramway points and the like. Fig. 1 shows a sectional view of the device taken transverse to the rails, in which 1 is the rail, 2 the movable point, 4 a casing enclosing the adjusting-device, and 6 the connecting - piece between the point and the casing 4. Fig. 2 shows a plan of the same with the road-box lid removed. The casing 4 has side arms, by means of which it is supported and can slide along the rods 5. This casing contains two pistons 8, 9, which are pressed apart by a spring 12 and are attached to the rods 10, 11. To damp the movement of these pistons, the casing is filled with oil, and valves 13, having snifting- orifices as described in Specification No. 4639, A.D. 1901, are used. Formed integral with this casing is a transverse cylinder 15 in which the locking-pieces 16 work, and which are pressed outwards by a spring placed between them. These pieces engage with projections 18, 19, the latter of which can be retracted clear of the projection 16, when desired. Pieces 22, 23 placed at each end of the box and connected by the bar 24 can be moved by a hand-lever 25, Fig. 4, so that either of the rods 10, 11 can be prevented from moving or both may be left free. When it is desired to arrange the point so that it can be moved by hand into either position, and automatically lock itself in that position when moved, the rods 10, 11 are left free and the projection 19 is moved outwards. When the point 2 is then moved into either position, the casing 4 and cylinder 15 move with it, and the projections 16 lock it in that position. To arrange the point so that it will always set in one position, the projection 19 is retracted and one of the pieces 22, 23 moved so as to fix one of the rods 10, 11 in position. When the point is then moved, the projections 16 are merely moved on one side, no locking action ensuing, and the spring 12 becomes compressed due to one of the pistons remaining stationary. The point thus always comes slowly to rest in the desired position when liberated. In the modification shown in Fig. 6, the projections 16 work in separate cylinders and mesh with a bar 28, which is also carried by the casing 4. When it is desired to lock the point, this bar is fixed in position by end pieces similar to those previously described. The connection between the bar 28 and the casing 4 is such that a certain amount of sliding can take place. An arrangement is also shown in which the point is directly connected to the locking-device, which is combined with a damping-arrangement, the rest of the arrangement not being used. Another modification is shown, in which the cylinder 15, shown in Fig. 2, is connected direct to the point by a rod, the locking-arrangement being otherwise the same. This rod has two collars formed on it, between which a spring is placed. When it is desired to make the point always set in a particular position, one of two projections is moved forward, so as to fit between one end of the spring and one of the collars, and so compress the spring when the point moves out of this position. The rods 5 are made in parts so as to make it easy to fix them in position or remove them when desired.