Abstract: The present invention provides a self-powered proportioner which can automatically, proportionally mix two fluids in a low ratio. A fluid gating means is disposed intermediate a fluid supply and a motor piston to cause reciprocating movement of the motor piston within a motor cylinder. A connecting rod secured to the motor piston is disposed within a cavity in the housing extending between the motor cylinder and a slave pump cylinder. A slave pump piston is secured to the connecting rod for providing responsive reciprocatory movement of the slave pump piston within slave pump cylinder for pumping a second fluid. A connecting rod seal is interposed between the cavity wall and the connecting rod intermediate the motor cylinder and the slave pump cylinder preventing fluid communication through the cavity between the motor cylinder and the slave pump cylinder.

Abstract: An improved variable proportioner is provided which includes a spring biased lost motion connection between the motor piston and the slave pump piston thus providing for accurate adjustability of the metering proportion as well as prevention of stalling of the slave piston against the front cylinder wall. A pivotable connection of the toggle lever spring is also provided to reduce bending of the spring and to enhance its life span.