CATALOG OP THE MECHANICAL COLLECTIONS 73; 



opened and closed with a regular movement. Similar rods from the 

 wrist plate extend to the arms on the rock shafts of the steam valves, 

 but these rods terminate in hooks that engage with toes on the ends 

 of the valve rock shafts and are not permanently connected thereto. 

 As long as the hooks are engaged the steam valves will be opened 

 and closed with a regular movement just as are the exhaust valves,, 

 but when disengaged the valves are free to close under the force of 

 weights permanently attached to the rock arms. The hooks are 

 caused to disengage at any point in the stroke of the engine piston 

 or not, as is desired, by means of adjustable stops that force the 

 hooks away from the toes of the rock arms. These stops are moved 

 by means of inclined blocks, the position of which (in the model) 

 is varied by a worm and rack set by hand, though the patent suggests- 

 that these blocks could be attached to the slide of the governor for 

 automatic regulation of the cut-off. The weights that close the steam 

 valves are nicely fitted to recesses in the engine frame so that air 

 may be trapped under them to cushion the fall of the weights and 

 bring them to rest without jar. The valves are flat slide valves 

 operated by the rock shafts through short arms on the shafts, which 

 connect to the backs of the valves with cylinder and cylindrical socket 

 joints. 



CORLISS STEAM PUMP, 1857 



U.S.N.M. no. 308722; original patent model; transferred from the Unitedi 

 Patent Office; not illustrated. 



This model was submitted with the application for the patent 

 issued to George H. Corliss, of Providence, R. I., June 2, 1857, 

 no. 17423. 



The invention offers a means of constructing a direct connected 

 steam pump in which steam can be worked with expansion without 

 employing a flywheel. The pump is an arrangement in one hori- 

 zontal plane of 15 radial cylinders (10 single-acting water cylinders 

 and 5 steam cylinders) in five groups, with each steam cylinder 

 flanked on either side by a water cylinder. Each connecting rod 

 from the cross heads of 14 of the cylinders works upon a pin in th& 

 enlarged disk-shaped end of the fifteenth connecting rod, which 

 works directly upon the crankpin. "In such a combination the vary- 

 ing pressure exerted by any one piston by working the steam ex- 

 pansively to the farthest practical limit does not affect the uniform 

 transmission of force to the pumps and the disc constitutes the 

 common recipient to which the collective force of the different steam 

 pistons is imparted and from which it is transmitted or distributed 

 to the pumps." 



49970 — 39 6 



