Injection molding press

An injection molding press for injection molding of resin materials, comprising:

• a hollow barrel for storing the resin amterials therein, said barrel having front and rear sides, a material inlet formed at the rear side thereof for introducing the resin materials therein, and valve seat means situated inside the barrel at an area between the front and rear sides,
• a sleeve having an injection nozzle at a front end and a through hole therein to allow the resin materials to pass therethrough when molding, said sleeve being partly slidably situated inside the barrel at the front side of the barrel so that the barrel slides relative to the sleeve,
• means for reciprocally moving the barrel relative to the sleeve connected between the sleeve and the barrel,
• a plunger situated in the rear side of the barrel, said plunger having valve body means at a front side thereof to engage with and disengage from the valve seat means of the barrel, and a side portion extending from a side adjacent the material inlet of the barrel to a portion adjacent the valve body means so that a space is formed between the side portion and inner surface of the barrel to allow the resin materials to pass therethrough and enter into the front side of the barrel only when the valve body means does not engage the valve seal means,
• means for rotating the plunger relative to the barrel to supply the resin materials from the material inlet to the front side of the barrel by means of the plunger,
• means for reciprocally moving the plunger relative to the barrel so that the valve body mean engages with and disengages from the valve seat means, and
• material supply means attached to the material inlet of the barrel, the resin materials to be injected being forcibly supplied from the material supply means to the material inlet,
• whereby when the barrel is placed in a rear position relative to the sleeve and the valve body means of the plunger is located away from the valve seat means of the barrel, the resin materials is supplied from the material supply means to the front side of the barrel through the space between the barrel and the plunger, and when the valve body means is engaged with the valve seat means and the barrel is moved relative to the sleeve, the resin materials retained in the front side of the barrel is ejected through the sleeve for molding.

An injection molding press for injection molding of resin materials, comprising:

• a hollow barrel for storing the resin materials therein, said barrel having front and rear sides, a material inlet formed at the rear side thereof for introducing the resin materials therein, and valve seat means situated inside the barrel at an area between the front and rear sides, said valve seat means having a tapered concave surface having th.RTM.diameter decreasing toward the front end of the barrel,
• a sleeve having an injection nozzle at a front end, a through hole therein to allow the resin materials to pass therethrough when molding, and a tapered concave surface at a rear end having the diameter decreasing toward the front end of the sleeve, said sleeve being partly slidably situated inside the barrel at the front side of the barrel so that the barrel slides relative to the sleeve,
• means reciprocally moving the barrel relative the sleevee connected between the sleeve and the barrel,
• a plunger situated in the rear side of the barrel, said plunger having valve body means at a front side thereof to engage with and disengage from the valve seat means fo the barrel, said valve body means having a tapered convex surface having the diameter decreasing toward the front end of the plunger so that the plunger snugly fits the valve seat means of the barrel and the tapered concave surface of the sleeve when engaged together, and a reduced diameter portion with a circular surface extending from a side adjacent the material inlet of the barrel to a portion adjacent the valve body means so that a space is formed between the reduced diameter portion and the inner surface of the barrel to allow the resin materials to pass therethrough and enter into the front sid of the barrel by means of the plunger only when the valve body means does not engage the valve seal means,
• means for rotating the plunger relative to the barrel to supply the resin materials from the material inlet to the front side of the barrel by means of the plunger,
• means for reciprocally moving the plunger relative to the barrel so that the valve body means engages with and disengages from the valve seat means, and
• material supply means attached to the material inlet of the barrel, said material supply means having a casing connected to the barrel and a plunger situated in the casing so that the resin materials in the casing is forcibly supplied from the material supply means to the material inlet by the plunger attached to the casing,
• whereby when the barrel is situated in a rear position relative to the sleeve and the valve body means of the plunger is placed away from the valve seat means of the barrel, the resin material is supplied from the material supply means to the front side of the barrel through the space between the barrel and the plunger, and when the valve body means is engaged with the valve seat means and the barrel is moved relative to the sleeve, the resin materials retained in the front side ofthe barrel is ejected through the sleeve for molding.