Injection molding apparatus for producing articles with a mottled appearance

In molding apparatus of the type in which materials of diverse coloration are mixed and melted within an injector mechanism and subsequently injected into a mold cavity to form an article of generally mottled appearance, the improvement wherein said injector mechanism comprises:

• a housing having inner bore-defining surface means and a discharge opening;
• a softener screw disposed in a rearward portion of said bore;
• actuating means operably connected to said softener screw to rotate said softener screw to displace said diversely colored materials forwardly and discharge said materials from said screw in a softened condition but short of a fully blended condition so that distinct color patterns are present;
• heating means for heating a portion of said housing forwardly of said softener screw;
• spreader means disposed in said bore intermediate said discharge opening and the front of said screw, said spreader means defining passage means at its outer periphery for spreading the softened materials of diverse coloration into a thin travel pattern along a heated portion of said housing for absorbing additional heat from said housing to facilitate melting of said spread materials of diverse coloration;
• said passage means being unobstructed at its inlet and outlet ends during said injection and being oriented to guide said spread materials of diverse coloration toward a discharge opening of said bore in directions substantially parallel to the axis of said bore to minimize blending of said colors and preserve the presence of distinct color patterns;
• means operably connected to said softener screw for advancing said screw in a manner displacing softened materials located thereahead toward said spreader means;
• and
• means for rotating said screw forwardly during advancement thereof.

In molding apparatus of the type in which materials of diverse coloration are mixed and melted within an injector mechanism and subsequently injected into a mold cavity to form an article of generally mottled appearance, the improvement wherein said injector mechanism comprises:

• a housing having inner bore-defining surface means and a discharge opening;
• a softener screw disposed in a rearward portion of said bore;
• actuating means operably connected to said softener screw to rotate said softener screw to displace said diversely colored materials forwardly and discharge said materials from said screw in a softened condition but short of a fully blended condition so that distinct color patterns are present;
• heating means for heating a portion of said housing forwardly of said softener screw;
• spreader means disposed in said bore intermediate said discharge opening and the front of said screw, said spreader means defining passage means at its outer periphery for spreading the softened materials of diverse coloration into a thin travel pattern along a heated portion of said housing for absorbing additional heat from said housing to facilitate melting of said spread materials of diverse coloration;
• said passage means being unobstructed at its inlet and outlet ends during said injection and being oriented to guide said spread materials of diverse coloration toward a discharge opening of said bore in directions substantially parallel to the axis of said bore to minimize blending of said colors and preserve the presence of distinct color patterns;
• said actuating means comprising pressurized fluid-actuated rotary motor means;
• pressurized fluid-actuated translational motor means being operably connected to said softener screw for advancing said softener screw and the softened mixture disposed thereahead toward said spreader means;
• and
• means for conducting pressurized fluid to said rotary motor means in a direction to oppose backward flow of the mixture during screw advancement.

In molding apparatus of the type in which molding material is heated within an injector mechanism and subsequently injected into a mold cavity to cure;

• the improvement wherein said injector mechanism comprises:
• a housing having an inner bore and discharge opening;
• a feed screw having helical thread means disposed in said bores;
• fluid-actuated rotary power means for rotating said screw forwardly to displace molding material toward said discharge opening;
• fluid-actuated translational power means for advancing said screw in a manner displacing molding material located thereahead toward said discharge opening;
• pressurized fluid supply means common to said fluid-actuated rotary power means and said fluid-actuated translational power means, said pressurized fluid supply means including fluid valve means for:
• delivering pressurized fluid to said fluid-actuated rotary power means to rotate the latter in a forward direction of rotation in the absence of forward translation of said feed screw, to advance molding material,
• delivering pressurized fluid to said fluid-actuated translational power means to urge the latter in a forward direction of translation during a material injection stroke, and
• delivering pressurized fluid to said fluid-actuated rotary power means simultaneously with the deliverance of pressurized fluid to said fluid-actuated translational power means to tend to urge said rotary power means in a forward direction of rotation to regulate the rotary behavior of said screw in a manner opposing backward flow of material being injected.