The lengths of the links comply with the condition: 0͞A=A͞B=a. Link 1, turning about fixed axis 0, is connected by a sliding pair to cross-shaped slider 3 which has guides perpendicular to each other. Link 2 has the form of a bent lever and turns about fixed axis A. Arm Bb of link 2 moves in slider 3. When link 1 turns about axis 0, point D of slider 3 describes cardioid q-q with the equation ρD=0͞D=a(1+cos(ϕ)) , where ϕ is the polar angle between vector ρD and polar axis 0x.
$1146$LG,Ge$