Cross-shaped slider 1 has guides with axes perpendicular to each other and moves along fixed guides p. Slider 1 is connected by turning pair A to link 2 which slides along the axis of link 7. Link 7 is connected by turning pair B to link 6 which, in turn, slides in guide q of slider 1. Links 4 and 5 are connected together by turning pair K and slide along the axes of links 6 and 2. Roller 3 has a sharp-edged rim and rotates about axis a-a. When slider 1 moves along axis x-x of guides p, roller 3, cutting into the surface of the drawing with its sharp edge, moves during each instant along straight line AB. Sliding link 2, whose axis is perpendicular to line AB, turns and point K describes an exponential curve with the equation y=b*e^(-ax) where a=A͞D, b = value of ordinate y at x=0, e = base of natural logarithms.
$1237$LG,Ge$