Figure 44. — Quick-return mechanism. Top, 

 Early representation of tiie quick-return mech- 

 anism patented by Whitworth in 1849, from 

 William Johnson, ed., The Imperial Cyclopaedia 

 of machinery (Glasgow, about 1855, pi. 88). 

 Middle, Sketch by Robert Willis from his copy 

 of Prirwiples of Mechanism (London, 1841, 

 p. 264), which "shews Whitworth dissected into 

 a simpler form"; it is as obscure as most subse- 

 quent attempts have been to explain this 

 mechanism without a schematic diagram. 

 Bottom, Linkage that is kinematically equivalent 

 to Whitworth's, from Robert Willis, Principles 

 oj Mechanism (London, 1841, p. 264). 





1^ /ii 



^- ^ /^^^w A-^^^ M:'-^-^ 



4i 



engineering," reflecting a dissatisfaction with the tra- 

 ditional branches of engineering, kinematics was a 

 senior subject and was taught from Rankine's Ma- 

 chinery and Millwork}^^ 



At Massachusetts Institute of Technology, Peter 

 Schwamb, professor of machine design, put together 

 in 1885 a set of printed notes on the kinematics of 

 mechanisms, based on Reuleaux's and Rankine's 

 works. Out of these notes grew one of the most dur- 

 able of American textbooks, first published in 1904."^ 

 In the first edition of this work, acceleration was men- 

 tioned only once in passing (on p. 4). Velocities in 

 linkages were determined by orthogonal components 

 transferred from link to link. Instant centers were 

 used only to determine velocities of various points on 

 the same link. Angular velocity ratios were frequently 

 noted. In the third edition, published in 1921, linear 

 and angular accelerations were defined, but no accel- 

 eration analyses were made. Velocity analyses were 

 altered without essential change. The fourth edi- 

 tion (1930) was essentially unchanged from the pre- 

 vious one. Treatment of velocity analysis was im- 

 proved in the fifth edition (1938) and acceleration 

 analysis was added. A sixth edition, further revised 

 by Prof. V. L. Doughtie of the University of Texas, 

 appeared in 1947. 



Before 1900, several other books on mechanisms 

 had been published, and all followed one or another 



11' Transactions oJ the American Society of Mechanical Engineers, 

 1885-1886, vol. 7, p. 757. 



'12 Peter Schwamb and Allyne L. Merrill, Elements of Mecha- 

 nism, New York, 1904. In addition to the work of Reuleaux 

 and Rankine, the authors acknowledged their use of the publi- 

 cations of Charles MacCord, Stillman W. Robinson, Thomas 

 W. Goodeve, and William C. Unwin. For complete titles see 

 the list of selected references. 



224 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



