STEAM ENGINES 



177 



Slotted-Lever Reducing Motions. A form of reducing 

 motion consisting of a swinging slotted lever is shown in Fig. 4. 

 The lever a is pivoted at b to a stationary frame or girder and 

 is slotted at c so as to fit over a pin d fastened to the crosshead 

 e. The indicator cord / is attached to the lever at g. 



Another form of slotted-lever reducing motion is shown in 

 Fig. 5. The lever a is pivoted at b and is slotted at its lower 

 end to fit over the pin c attached to the crosshead. The 

 indicator cord d is fastened to a bar e that slides in the guides /. 



FIG. 6 



FIG. 7 



A pin g fixed in the bar e fits in a short slot in the upper end 

 of the swinging lever. As the crosshead moves to and fro, the 

 bar e , and hence the indicator cord also, copies the motion of 

 the crosshead to a reduced scale. 



Pantograph Reducing Motion. The type of reducing 

 motion shown in Fig. G is termed a pantograph. It consists of 

 four straight bars a, b, c, d joined together with pin joints to 

 form a parallelogram. One of the end bars d is prolonged, as 

 shown, and is pivoted to the crosshead of the engine at e. 



