Connecting rod 2 is connected by turning pairs to slider 3 and to rocker arm 1 of four-bar linkage ABCD. Reciprocation of slider 3 is converted by connecting rods 2 and 5, and rocker arm 1 into rotation of crank 4 about fixed axis D. Rocker arm 1 oscillates about fixed axis A. The lengths of the links comply with the condition: A͞D+D͞C<C͞B+A͞B. Special counterweights are required to balance rocker arm 1 with respect to axis A.
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