The lengths of the links comply with the conditions: A͞B=D͞C, B͞C=A͞D, G͞B=G͞D and A͞B<B͞C. Figure A BCD is a crossed-crank linkage. Link 1, turning about fixed axis A, is connected by a sliding pair to slider 5 and by turning pairs B to links 3 and 8. Link 4, turning about fixed axis D, is connected by a sliding pair to slider 6 and by turning pair C to link 3. Sliders 5 and 6 are connected together by turning pair E. Link 9, turning about axis D, is connected by turning pairs G to link 8 and slider 2. Slider 2 moves along axis Ee of link 7 which is connected by turning pair E to sliders 5 and 6. Centres A and D are placed at the foci of a hyperbola. Then point E describes the hyperbola and straight line Ee envelops this hyperbola.
$1084$LG,Ge$