The Locomotive Of Today

The Engine : Stationary Link Motion. 95 placed with their flanges projecting towards each other; Alling or distance pieces are inserted and secured at each end, for keeping- them the desired distance apart. The quadrant block is in two pieces, one of which. is in each channel, with a pin passing through them and the end of the radius rod between them, or the radius rod may have projecting lugs upon it, to take the blocks. Projecting lugs are also formed upon the outsides of the link to take the forked ends of the eccentric rods and the ends of the suspension link respectively. The curvature of the link is made equal to the length of the radius rod. The box link is employed when it is desired to get a short eccentric throw, as with it the travel of the valve in full gear approximately equals the diameter of the eccentric circle. Ordinary links are also usecl, especially in inside cylindered engines, when the width of the box links makes it difficult to place them closely enough together, especially if the valves are between the cylinders. The eccentric rods are similar to those used for a solid slot link, excepting that the fork is made in two pieces and joined together by means of bolts ; either this expedient must be resorted to or the link must be taken to pieces every time the eccentric rods are taken off or put on ; it therefore follows that this end must be coupled up first, then the butt end placed on the studs and secured. The suspension links are hung from a point above the link and should be as long as possible, so that the rise of the link at each end of its stroke should cause the least interfer- ence with its proper movement. A length equal to that of the radius rod is considered best as it also minimises the slip, but it cannot always be obtained on locomotives on account of the height of the boiler. The radius rod is usually forked to clear the valve spindle, which is continued through a guide, this assists it to withstand the thrust of the radius rod, and ensures it working fair. The raising or lowering of this rod is effected by bell cranks upon the reversing shaft as shown, and the engine is reversed by bringing the valves more under the influence of either eccen- tric as required, by raising or lowering the quadrant block in link. On the sketch it is not in mid-gear, but is shown slightly raised towards the fore-gear eccentric . rod end, to make the drawing clearer, as the two centres, if coincident, woulcl be liable to lead to confusion. As the radius of the link is equal to the length of the radius rod, when the crank is on its dead centre and the port open to lead, reversing the motion simply lifts or lowers the