STEAM STATIONARY RECIPROCATING, for the Rice engine.) The ..lichdosh & Seymour Governor.—Fig. 5 repre sents the governor used on the McIntosh & Seymour en gines (see ENGINES, STEAM STATIONARY RECIPROCATING) up to 150 horse-power with the weights in their two extreme positions, the details of the different parts being shown in Fig. O. In common with other so-called shaft-governors, it is a device for regulating the speed of the engine by centrifugal weights and opposing springs, which control the point of cut-off by swinging the eccentric across the shaft. The centrifugal weights are pivoted, and are pro vided with inclined jaws. 11 hen the weights move, the inclined jaws acting' through the blocks (which slide in them and turn on a boss on the pendulum) change the posi tion of the pendulum. This may be termed a wedging action, and though the slightest force acting on the weights is sufficient to affect the position of the pendulum. the reverse is not true, and the weights are undisturbed by the effort of the valve-gear on the pendulum. The freedom from friction of the governor is due principally to the use of a plate-spring opposing the centrifugal force of each weight and acting through a steel pin. hardened and resting in hardened steel cup sat both ends. The cup in the weight is situated at the center of gravity. so that the centrifugal force is directly resisted by the spring in a frictionless manner. Tie double spring, will keep the tension on the weights equal, notwithstanding any slight inequality in the adjustment of the length of the pins, Since the two weights move together in an opposite direction, they are in statical equilibrium in all positions. The pressure of the valve-gear transmitted through the pendulum and blocks is transferred several times during each revo lution between the opposite jaws of each weight. This action is important. since it affords every opportunity for a most delicate balancing of the centrifugal force and oppos ing resistance of the spring.
The speed of the engine can be changed, if it is desired, by adding to or taking from the weight of the centrifugal weights.
The Giddings Governor, shown in Fig. 7, consists of two eccentrics ; the auxiliary eccen tric rotating on the hub of the governor-disk by the usual system of weight-arms and levers as shown. This eccentric has a cross-head strap which gives a motion square across the shaft. preserving a constant lead. The main eccentric, as shown. fits over this cross-head by means of lugs, and its throw is varied by the movements of the same, thereby changing the travel of the valve to give the required port-opening for varying loads and boiler pressures, at the same time preserving uni formity of motion. This combination of two eccentrics gives great stability, as it is me chanically locked in every position.
The Armington & Sims Automatic Cut-off Regulator (Figs. 8 and 9) consists of a wheel which is fixed to the engine-shaft, to which are hinged the weights 11; these weights are controlled by springs, one end of the same be ing seated in a pocket fixed on the spoke of the wheel, or in some eases attached directly to the rim of the wheel. The inner eccentric,
marked C, having ears attached, is placed close to the regulator-wheel. and is free to turn upon the shaft. From the ears rods (2 2) are connected with the regular weights. On the outside of the inner eccentric, and free to turn, is placed an eccentric ring from which a rod (3) is connected to the toe of one of the weights. On this outer eccentric ring are the usual effpntrie straps, to which are directly attached the valve-rod. When the engine is run ning at its greatest velocity, the weights, dile to the centrifugal force overcoming the springs, will he out, The eeeentricity of the t wo combined eccentrics is I lien the distance shown at A, in Fig. 8. The other extreme. when the engine has its greatest load requiring later cut-off, the position of the weights will be as shown in Fig. 9. It will lie seen that when the weights are in such position. the inner eccentric has been moved back, and the outer eccentric forward or in the opposite direction, and the eccentricity by this combined movement is increased. This is sufficient to allow the steam to follow the piston to about seven tenths of the entire stroke. This wide range from the simple lead of valve, as shown at A, causes extreme sensi tiveness of the regulator. The lead in all positions of the eccentrics remains constant and is practically unchanged.
The Woodbury Engine - Ciorernor (Fig. 10) is of that class in which the point of cut-off or valve-closure is effected by moving the eccentric across the shaft, thereby varying the length of the valve travel. The movement of the eccentric is operated by centrifu gal weights, the centripetal or opposing force being furnished by a single spiral spring. Fig. 10 is a side elevation of the governor. The weight A is bolted to the eccentric arm, and is therefore pivoted to the fly-wheel at B, the same point as the eccentric itself. The weight A' is adjustable on the lever D, which is pivoted to the fly-wheel at H, and connected to eccentric 0 through the link E. Rubber buffers (not shown) at point a and point b form stops for the extreme inward position of the weights, and the one at c for the ex treme outward position. In the posi tion shown, the weights are at their ex treme inward point of movement, the center of eccentric being at d, and cor responding to point of cut-off by the valve at I stroke. In the extreme outward position of the weights the center of the eccentric is moved to e, where the eccentric gives to the valve its least travel, the point of closure or cut-off being at zero. (See ENGINES, STEASI STATIONARY RECIPROCATING, for the Woodbury engine.)