초록 ▼

A process of producing a moulding by introducing thermoplastics material into a mould space through gate means having a passageway, which process includes the formation of a sprue in the passageway. A retractable member cuts off the sprue before the material solidifies and closes the passageway at i

A process of producing a moulding by introducing thermoplastics material into a mould space through gate means having a passageway, which process includes the formation of a sprue in the passageway. A retractable member cuts off the sprue before the material solidifies and closes the passageway at its junction with the mould space, the sprue being subsequently ejected from the passageway of the gate means before the next moulding cycle. A holder provides the gate means and the retractable member which is preferably inclined to the passageway. The gate means may also provide air ejecting means for removing the sprue and may conveniently be bolted onto an otherwise conventional injection moulding machine. The retractable member may incorporate a feed pipe for injecting a fluid into the plastics material.

대표청구항 ▼

A holder for the sprue of an injection moulding machine, the holder comprising gate means having a passageway through which the material to be moulded is injected into the moulding space and within which a sprue is formed and from which the sprue is ejected during each operating cycle, the passagewa

A holder for the sprue of an injection moulding machine, the holder comprising gate means having a passageway through which the material to be moulded is injected into the moulding space and within which a sprue is formed and from which the sprue is ejected during each operating cycle, the passageway having an inlet end and an outlet end open to the mould space, and the gate means including a retractable ram inclined to the passageway, the ram being movable between a withdrawn position and a position in which the ram closes the outlet end of the passageway, the ram simultaneously cutting off the sprue from the moulding.