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



551. I. Fairs of Kinematic Elements. 



(.) LOWER PAIBS. 



1 . Turning or cylinder pair. 



2. Sliding or prism pair. 



3. Twisting or screw pair. 



552. Fairs of Kinematic Elements. 



(b.) HIGHER PAIRS. 



4. Equilateral duangle in equil. triangle. 



These models of the higher pairs of elements can be inverted ; 

 that is, the movable element can be fixed, and the fixed element 

 made movable. The centroids are shown in thick black or red 

 lines ; the roulettes, or point-paths, in thinner lines. 



5. Expanded duangle in equil. triangle. 



6. Equilateral curve-triangle in square. 



7. Equilateral curve-triangle in rhombus. 



8. Expanded isosceles curve-triangle (90) in square. 



9. Expanded equilateral curve-triangle (90) in rhombus. 



10. Regular curve-pentagon in square. 



11. Symmetrical curve-pentagon in square. 



553. II. Conic Axoids, with corresponding Spheric 

 Roulettes and Profiles. 



12. Spheric epicycloid. 



Eatio 1:3. 



13. Spheric cycloid. 



A full cone rolling upon a plane cone (1:3). 



14. Spheric hypocycloid. 



A full cone rolling in an open one (2:1). 



15. Spheric hypocycloid. 



Ratio 1:3. 



16. Spheric pericycloid. 



The curve upon the rolling cone passes always through the de- 

 scribing point of the fixed one. 



17. Spheric involute. 



Eatio 1:3. 



18. Spheric involute. 



Batio 8:9; the curve in red is a curtate involute. 



1 9. Apparatus for describing spheric cycloids. 



Describes, among other curves, those here exhibited. 



