Injection molding apparatus providing a strippable flash for producing a plurality of flash-free articles

Claim 1

Molding apparatus providing a stripable web of flashing material for producing a plurality of flash-free articles upon removal of said web, said apparatus comprising: first and second mold members having a plurality of articleforming first cavities and a plurality of second cavities when assembled with opposing surfaces in face-to-face relationship; force applying means compressively urging said first and second members together; injection means for injecting a molding material into said first cavities under pressure and urging said first and second members apart; said first and second members having a first position defined by opposing surfaces of said members in abutting engagement when the force of said applying means is greater than the force in said first cavities from said injecting means; said first and second members having a second position defined by the opposing surfaces of said members being spaced apart a substantially uniform predetermined distance when the force in said first cavities from said injection means is greater than the force from said applying means by a predetermined amount; said predetermined distance defining a plurality of flash passages, each passage interspersed between and in communication with each first and second cavity; said injection means supplying sufficient molding material to substantially fill said second cavities when said mold is in its second position; and a runner plate communicating said injection means with said cavities, said runner plate including an opening communicating with said injection means and a plurality of runner and branch runners extending from said opening and providing flow channels to said first cavities, said branch runners orientated with respect to said runner so as to provide substantially uniform pressurized flow of said resilient material to each one of said first cavities whereby said first and second mold members separate at said substantially uniform predetermined distance.