HYDRAULIC TRANSMISSION GEAR 



781 



working in cylinders A. The ring is eccentric with respect to the centre 

 line of the gear, its eccentricity being capable of regulation as desired. 

 The cylinders A form a single casting keyed to the jaw clutch K which 

 is coupled directly to the engine shaft. The supply of fluid to or from 

 the cylinders is regulated by means of a circular rotary valve V with 

 supply and discharge ports. The eccentricity of the ring R determines 

 the stroke of the pistons in these cylinders and thus the volume of fluid 

 displaced by them per revolution of the engine. 



A second set of four cylinders B, of the same size as A, are keyed to 

 the jaw clutch N which is coupled direct to the driving wheels. The 



FIG. 394. Hydraulic Transmission Gear. 



connecting rods of these pistons are coupled to a single crank pin // with 

 fixed throw and thus have a constant stroke, while the crank shaft H is 

 keyed to one half of the cone clutch M but is otherwise free to rotate 

 relatively to the frame of the motor. The compound clutch M consists 

 of three parts, one of which is fixed to the frame, one to the shaft H, and 

 one to the cylinders A, and by suitable manipulation the shaft H may be 

 either clutched to the frame or to the cylinder A. Assuming these 

 cylinders to be rotating continuously in one direction with the engine, the 

 action of the apparatus is as follows. 



(1.) Cylinders A and Crank Shaft H both declutched. Liquid pumped by 

 pistons A is circulated freely through the system along the pipe S and 

 through cylinders B, causing shaft H to rotate idly in its bearings, with 



