64 BULLETIN 173, U. S. NATIONAL MUSEUM 



of the block and move with the lift rod as it is rising and the valve 

 is opening, then the block moves so that the roller comes to the edge 

 of the inclined portion and rolls down the incline permitting the 

 valve to drop more quickly than the lift rod. The movement of the 

 block on the arm and consequently the point of cut-off are fully 

 adjustable. 



SICKELS TRIPPING CUT-OFF VALVE, 1852 



U.S.N.M. no. 308654, original patent model ; transferred from the United States 

 Patent Ofl5ce ; not illustrated. 



This model was submitted with the application for the patent is- 

 sued to Frederick E. Sickels, of New York, N. Y., February 24, 1852, 

 no. 8760. 



The model represents a valve chest and drop cut-off valve of the 

 Sickels type (see above) in which an adjustable cam operates the catch 

 during the opening movement of the valve so that the valve may 

 be released as near the beginning of the closing movement as is 

 desired. In the earlier cut-offs the catch was operated by the closing 

 movement alone, and the valve could not be tripped until sufficient 

 closing movement had taken place to operate the whole extent of the 

 catch. 



UHRY AND LUTTGENS VALVE GEARING, 1855 



U.S.N.M. no. 308656; original patent model; transferred from the United States 

 Patent Office ; not illustrated. 



This model was submitted with the application for the patent 

 issued to H. IJliry and H. A. Luttgens, of Paterson, N. J., March 20^ 

 1855, no. 12-564. 



The model represents a "link motion" applicable to marine, loco- 

 motive, or stationary steam engines. It is a combination of three 

 eccentrics, the ordinary Stephenson link motion, an additional link 

 pivoted to the Stephenson link, a differential rocker, and a main 

 rocker. The main rocker and the Stephenson link operate one valve, 

 which distributes steam to the cylinder, supplies outside lead, and 

 cuts off the steam in proportion to the decrease of travel. The 

 valve operated by the differential rocker exhausts the steam and 

 opens and cuts off the admission of steam near full stroke of the 

 piston. 



ALLEN TWO-MOTION CONE-VALVE, 1855 



U.S.N.M. no. 308655 ; original patent model ; transferred from the United States 

 Patent Office; not illustrated. 



This model was submitted with the application for the patent 

 issued to Horatio Allen, of New York, N. Y., June 19, 1855, no. 13075. 



