Mixing head for reactive components

A mixing head for two reactive components comprising:

• housing means forming a mixing chamber and having respective inlets supplied with said components and adapted to open into a mold cavity;
• a control member displaceable in said housing means between a first position wherein flow from said inlets into said chamber is blocked and residual mixtures of said components are displaced from said chamber, and a second position wherein flow from said inlets into said chamber is unblocked, said control member defining passages for recirculating said compartments from said inlets in said first position of said control member;
• a first cylinder arrangement including a piston operatively connected to said control member and hydraulically actuatable to shift said control member between said positions;
• a displacement body laterally shiftable into and out of said chamber for controlling the mixing of said components thereof;
• a second cylinder arrangement having a piston connected to said body and hydraulically operable to shift said body into said chamber;
• a third cylinder arrangement mounted on said housing means and having a piston positioned for mechanical displacement by the piston of said first cylinder upon movement of said member from said first position to said second position to displace hydraulic fluid from said third cylinder arrangement;
• and
• a duct connecting said second and third cylinder arrangements whereby the movement of the piston of said third cylinder arrangement induces movement of the piston of said second cylinder arrangement, and independent of the hydraulic operation of said first cylinder arrangement, for establishing hydraulic fluid communication therebetween for shifting said body into said chamber upon movement of said member from said first position to said second position and for withdrawing said body from said chamber upon movement of said member from said second position toward said first position.