Mechanism capable of automatically cutting off gate in mould

The utility model provides a mechanism capable of automatically cutting off a gate in a mould. The mechanism is applied into an injection molding mould. The mould comprises an upper fixing plate, a female mould plate, a male mould plate with a male mould core, an ejection plate and a lower fixing plate, wherein a lateral gate or a tab gate is arranged on the male mould core. The mechanism capable of automatically cutting off the gate in the mould is characterized by comprising a gate cutting insert, a transmission ejection pin, an inclined pushing block and an oil pressure cylinder, wherein the upper end of the gate cutting insert penetrates through the male mould core and can be movably arranged below the gate vertically; the upper end of the transmission ejection pin penetrates through the lower fixing plate, the ejection plate and the male mould plate to abut against the lower end of the gate cutting insert; the inclined pushing block can be slidingly arranged in the lower fixing plate laterally, and the u