The lengths of the links comply with the conditions: A͞E=C͞F=m and E͞D=D͞F=E͞B=B͞F=n. Figure EBFD is a rhombus linkage. Links 3 and 4 are connected by turning pairs A and C to sliders 1 and 5 which move along fixed guides p-p. When point D is moved along a curve with the equation F(x,y)=0, point B describes curve P(ξ,η)=0. Coordinates x, y, ξ and η are related by the conditions x=ξ and y=kη where k=-((m+n)/(n-m))=const.
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