In mold assembly of two hinges

A method of forming a 4-bar kinematic link comprising the steps of:

• providing a rotary tool having a rotary platen rotatable at least one hundred eighty degrees and at least one linearly moveable platen capable of moving between an open position and a closed position relative to the rotary platen;
• providing on the rotary platen a first forming region having a rotary base member forming surface, an rotary upper arm forming surface and a rotary lower arm forming surface, a second forming region having a rotary base member forming surface, a rotary upper arm forming surface and a rotary lower arm forming surface;
• providing on the at least one linearly moveable platen having a first forming region having a linear base member forming surface, a linear upper arm filler surface, a linear lower arm filler surface, the at least one linearly moveable platen including a second forming region having a linear base member forming surface, a linear upper arm forming surface and a linear lower arm forming surface;
• providing at least one first shot injection port connected to the first forming region of the at least one linearly moveable platen and at least one second shot injection port connected to the second forming region of the at least one linearly moveable platen;
• providing a first shot of molten material and a second shot or molten material;
• moving the at least one linearly moveable platen toward the at least one rotary platen and creating a first base member molding cavity which is a closed cavity defined by the first forming region of the rotary platen and the first forming region of the at least one linearly moveable platen and creating a first arm member molding cavity which is a closed cavity defined by the second forming region of the rotary platen and the second forming region of the at least one linearly moveable platen;
• injecting the first shot of molten material through the at least one first shot injection port into the first base member molding cavity and forming a base member from the first shot of molten material;
• opening the first base member molding cavity and the first arm molding cavity by moving the at least one linear moveable platen away from the at least one rotary platen, wherein the formed base member stays on the surface of the rotary base member forming surface of the first forming region of the rotary platen;
• rotating the at least one rotary platen about an axis so that first forming region and the formed base member become aligned with the second forming region of the at least one liner moveable platen;
• moving the at least one linearly moveable platen toward the at least one rotary platen and creating a second base member molding cavity which is a closed cavity defined by the second forming region of the rotary platen and the first forming region of the at least one linearly moveable platen and creating a second arm member molding cavity which is a closed cavity defined by the first forming region of the rotary platen and the second forming region of the at least one linearly moveable platen, wherein the formed base member is contained within the second arm member molding cavity;
• injecting the second shot of molten material through the at least one second shot injection port into the second arm member molding cavity to form an upper arm member and lower arm member, wherein the second shot of molten material flows into contact with and between the rotary upper arm forming surface and the linear upper arm forming surface and the second shot of molten material flows through an upper set of apertures in the base member to form a hinge pin portion of the upper arm, wherein the second shot of molten material flows into contact with and between the rotary lower arm forming surface and the linear lower arm forming surface and the second shot of molten material flows through a lower set of apertures in the base member to form a hinge pin portion of the lower arm;
• curing the second shot of molten material in the second arm member molding cavity for form the 4-bar kinematic link, wherein the molten material of the second shot shrinks thereby creating a clearance between the hinge pin of the upper arm and the upper set of apertures in the base member to allow the hinge pin of the upper arm to rotate freely in the upper set of apertures in the base member and creating a clearance between the hinge pin of the lower arm and the lower set of apertures in the base member to allow the hinge pin of the lower arm to rotate freely in the lower set of apertures in the base member;
• and
• moving the at least one linearly moveable platen away from the at least one rotary platen and removing the 4-bar kinematic link.