120 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS. 



5291. Link Motion. William Howe, Chesterfield. 



The sketch was made by W. Howe, in August 1842, which was the first 

 sketch of the shifting link motion. The small rough wooden model was begun 

 by William Howe, in or about 1838, at the Vulcan Foundry, near Warrington, 

 Lancashire, where the sectional cylinder, piston, valve, and foundation frame 

 were made, but this was not for the purpose of applying the link motion, but 

 a tappet motion. When the sketch referred to above was made, the link 

 motion was applied to that model, and all the parts of the old model that 

 could be brought in were used. The model of the twin bar link was designed, 

 in 1848, by William Howe and Mr. William Usher, who was on a visit to 

 William Howe at the time he made the model. 



76c. Instrument, with joint, which makes its upper part 

 moveable in a horizontal plane. 



Professor Tchebichef, University of St. Petersburg. 



76d. Model of joint, which directly transforms a reciprocating 

 into a circular motion. 



Professor Tchebichef, University of St. Petersburg. 



530. Drawing and Model of a connecting motion between 

 two shafts turning in reversed ways. Charles Bourdon. 



53Oa. Pour Models, for the description of tooth -profiles, and 

 lines of contact. 



Royal Rhenish Westphalian Polytechnic School at Aix-la- 

 Chapelle. 



Model No. 1 illustrates the construction of general toothing, according to 

 Keuleaux's method. 



Model No. 2 shows that by the describing point of a string which runs 

 over two rollers, two evolvents constantly coming in contact are marked 

 relatively to them, which for this reason are tooth-profiles correctly working 

 together. 



As the same profiles are described when the axes are distanced from or 

 brought nearer to each other, it follows that evolvert-wheels may alter the 

 distance of their axis notwithstanding the correct contact. 



The top circles " K" and " K x " cut off from the contact line " a 6, the 

 contact space PP. 



Model No. 3 shows that at the cycloid toothing, the " contact space " con- 

 sists of the curves (segments) cut off from the head circles, and that every 

 normal placed on the tooth-profile in the common point of contact of two 

 teeth always passes through the point of contact of the two dividing circles. 



Model No. 4 evolves spontaneously the circumferential line of the possibly 

 smallest space between the profiles. 



530b. Model of "Weston's Differential Pulley, with 

 weights complete. 



Polytechnic School at Halle, Director Kohlmann. 



