The Spring Adjustment

The adjustment of the spring tension is made by a worm actuating a worm wheel on a rod passing through the spring, and to which one end of the spring is attached, the other acting on an arm that projects into a slot in the governor spindle. It is obvious that the speeder can be adjusted while the engine is running.

In Fig. 3319 the governor is shown with the speeder and Sawyer’s valve, the latter enabling the governor valve to be opened or closed without affecting the rise and fall of the governor balls, which is done by operating the arm shown on the right, whose ends are provided with loops, so that a cord may be attached, enabling the engineer to operate the governor from a distance.

The safety stop or stop motion is shown on the right, Fig. 3320.

It acts to close the governor valve and stop the engine in case the belt that drives the governor should get off the pulley or break. This stop motion consists of a pulley suspended by a rod, and riding on the belt which supports its weight. Should the governor belt break, this pulley falls and severs the connection between the valve and the governor, closing the valve, and holding it closed. Fig. 3321 shows the governor in section to expose the construction of the valve. The valve v is what is termed a poppet or poppet valve, which is balanced, because the steam entering at i, and taking the course denoted by the arrows, acts equally on both ends of the valve and does not press it in either direction, while as the steam surrounds the valve it is not pressed sideways.

At b is a gland or stuffing box to keep the spindle or rod steam-tight. At a is the slot for receiving the arm from the speeder and from the stop motion.

p is obviously the driving pulley, imparting motion to the bevel wheels g, which drive the outer spindle s, the inner spindle s′ being connected to a. The balls are upon ribbon springs d, which are secured at their lower ends to a link fast to the spindle s.

The centrifugal force generated by the balls causes them to move outwards, their upper ends pulling down the cap to which they are secured, and this cap operates the valve.

Governors of this class are sometimes termed fly-ball governors.