GOVERNOR

A contrivance for regulating the speed of machinery, which has long been in use in mill-work,_but has of late years attracted more attention by its adaptation to the steam-engine. It consists of two heavy balls B B, attached to the extremities of two rods B F, B F, which play upon a joint at E, pa ing through tical shaft a mortise1) D. in These the ver-are united by joints at F to the short rods F II, which again i are connected by joints at II to a ring which slides on the shaft D D. A horizontal wheel, W, is attached to D D, having a groove to receive a rope or strap on its rim, by means of which the motion is communicated toD D from a corresponding wheel on some shaft of the machinery to be regulated. It is evident, from the disposition of the rods, that if the balls B B are by any means raised or drawn asunder, the extremities P F of the rods turning on the pivot E will also be separated, and their distance from the axis increased. This will draw the rods F II in the same direction, and cause the ring or collar H to descend. This ring is connected with the end I of a lever, whose fulcrum is at G, and whose other extremity K is connected by some means with the part of the machine which supplies the power. Suppose now the velocity from any cause to undergo a sudden increase; by reason of the increased centrifugal force arising from the whirling motion, the balls B B will recede from the shaft D D, and raise the extremity K of the lever. On the other hand, if the velocity is diminished, the centrifugal force of the balls will be diminished,and they will fall by their own weight nearer the axis, and cause the end K of the lever to descend. When the governor is applied to a steam-engine, the rod K 1 com municates with a flat circular valve V, placed in the prin cipal steam-pipe, and so arranged that when K is elevated as far as the divergence of the balls will allow, the opening of the pipe will be closed by the valve V, and the pa age of steam entirely stopped. On the other hand, when the balls subside to their lowest position, the valve will be en tirely open. Thus, when the velocity Ls increased, the suo- [s. 538]