Pump operating mechanisms

Pump operating mechanism to provide a long power stroke for a pump piston rod (7) or the like having

• a support frame (11, 12);
• two spaced wheels (1, 2) mounted on said frame, aligned in a single plane and having parallel axes of rotation;
• an endless roller link chain (5) looped about said wheels, said chain defining an area enclosed therein within which said wheels are positioned;
• drive means (13) drivingly connected to at least one of said wheels;
• a plate (6);
• means (15) pivotally connecting the piston rod (7) to the plate;
• and attachment means securing said plate (6) to said chain (5) comprising
• three bolts (9, 9') corresponding to an equal number of pins joining links of the roller link chain adjacent each other, said plate being formed with openings receiving said bolts, the end openings being elongated to permit travel of the chain, with the plate attached, about said wheel and pivoting by the plate with respect to the links of the link chain;
• said plate projecting into said area, being positioned parallel to the wheels and a small distance from them, and extending at least two an imaginary line connecting the two axes of said wheels, the free end of said plate coinciding with said imaginary axis of alignment of the axes of the wheels,
• the plate moving in unison with said chain and pivoting in a plane parallel to the plane of said wheels, the piston rod pivot means (13) being positioned on said plate at said imaginary straight line and remaining at all times contained in an imaginary parallel and aligned plane including said line and at the same level as said imaginary straight line which connects the axes of said wheels.