CATALOG OF THE MECHANICAL COLLECTIONS gg 



will come into contact with the abutments and tend to turn the loose 

 cylinder. Attached to the loose cylinder is a pinion that meshes with 

 a toothed sector, which, in turn, is connected with the counterweight 

 on a lever arm raised by the turning movement of the loose cylinder 

 and so tends to oppose the turning of that cylinder. As the height to 

 which the counterweight will be raised is a function of the velocity 

 of the engine, this velocity can be governed by properly connecting 

 the counterweight to the cut-off or throttle valve. 



WOODBURY SHAFT GOVERNOR, 1870 



U.S.N.M. no. 251290; original patent model; transferred from the United States 

 Patent OlHce ; not illustrated. 



This model was submitted with the application for the patent issued 

 to Daniel A. Woodbury, of Rochester, N. Y., September 27, 1870, no. 

 107746. 



This is a very simple form of shaft governor in which the position 

 of a shifting eccentric is varied by the combined action of centrifugal 

 weights and springs; so that changes in the engine speed change the 

 'effective throw of the eccentric and the angle between the eccentric 

 and the crank to change the timing of the valve relative to the piston 

 and thus regulate the speed of the engine. 



The eccentric disk is held in a short lever that swings about a pin 

 attached to a spoke of the flywheel so located that the eccentric is 

 •approximately in the same position that would be occupied by an 

 ordinary fixed eccentric. In swinging about the pin the throw or 

 center of the eccentric changes its position relative to the center of 

 the shaft and the engine crank. The lever is connected by curved 

 links to two weights, Avhich are held by stiff flat coiled springs, so 

 arranged that an increase in speed causes the centrifugal force due 

 to the weights to move the lever slightly against the resistance of the 

 springs and swing the eccentric so as to advance the eccentric and 

 decrease the throw. The effect of this is that cut-off will occur earlier 

 and the engine speed tend to decrease and return to the former slower 

 speed. The arrangement of the weights is such that they are not 

 swung out suddenly by their inertia when the engine is suddenly 

 started, a difficulty often resulting in cut-off occurring so soon as to 

 stop the engine on dead center. 



JUDSON AND COGSWELL GOVERNOR, 1875 



U.S.N.M. no. 309244 ; original patent model ; transferred from the United States 

 Patent Office; not illustrated. 



This model was submitted with the application for tlie patent issued 

 to Junius Judson and William A. Cogswell, of Rochester, N. Y., 

 November 9, 1875, no. 169815. 



The model represents a flyball governor in which the driving pulley 

 is fitted loosely to the driving shaft and connected to it by a spiral 



