Link 1 turns about fiwed axis A and is connected by turning pair B to slider 4 which, in turn, moves along the axis of link 5. Link 3 is connected by turning pair K to link 5 and slides in guide a of link 1. The axis of guide a is perpendicular to line AB. Roller 2 has a sharp-edged rim and rotates about axis b-b. When link 1 turns about axis A, roller 2, cutting into the surface of the drawing with its sharp edge, moves during each instant along the straight line BK• The envelope of the successive positions of straight line BK is a hyperbolic spiral with the polar equation, with respect to pole A, ρϕ=a where ρ=A͞K, a=A͞B, ϕ = angle of rotation of radius vector ρ.
$1233$LG,Ge$