The mechanism is based on four-bar linkage ABCD. Added to this linkage is a double guiding element consisting of two sliders, 5 and 6, connected together by turning pair E. Links 1 and 3 have wheels 7 and 8 wi th sharp-edged rims which can only rotate about their axes. The mechanism is intended for tracing the roulettes of the centrodes of links 2 and 4. For this purpose, a stylus at the centre of pivot E is placed on the curve wi th respect to which the roulet te of the centrode of link 2 or 4 is to be obtained. Wheels 7 and 8 are set on a plane table. When the stylus of pivot E is moved along the above-ment ioned curve so that wheels 7 and 8 roll along the plane table, any point of plane members G and H, at tached respectively to links 2 and 4, describes the corresponding roulet te of the centrode of link 2 or link 4. Shown is roulet te f-f of centrode C₂ of link 2. It is described by point F of link 2 when the stylus of pivot E is moved along straight line a-a. This corresponds to the rolling of body centrode C₂ along straight line a-a. The mechanism can be set up for various centrodes by adjust ing pivots B, C and D along the corresponding slots as required.
$1238$LG,Ge$