Injection molding unit

In an injection molding machine including an injection mold assembly, an injection molding unit, a first drive means for inserting the injection molding unit on and withdrawing it from said injection mold assembly;

• said injection molding unit including a carrier block having a central longitudinal bore, a plasticizing cylinder normally projecting into said central longitudinal bore and having a longitudinal axis, a feed screw coaxially received in said plasticizing cylinder and being arranged for a rotary motion and an axial shifting motion relative to said plasticizing cylinder, coupling means for releasably axially immobilizing said plasticizing cylinder in said central longitudinal bore relative to said carrier block;
• said injection molding machine further having a second drive means for rotating said feed screw relative to said plasticizing cylinder, an injection cylinder means for periodically axially shifting said feed screw relative to said plasticizing cylinder and stationary columns supporting said carrier block for displacements thereon together with said plasticizing unit;
• the improvement wherein said plasticizing cylinder has an outer circumferential locking groove, said carrier block has inner radial guide faces and said coupling means has a plurality of locking bolts radially slidably supported on said radial guide faces;
• said locking bolts having a locking position in which they project into said circumferential locking groove and an unlocking position in which said locking bolts are radially withdrawn from said circumferential locking groove, a third drive means operatively connected with said locking bolt for causing radial movement thereof into the locking or unlocking positions;
• a fourth drive means being operatively connected to said plasticizing cylinder for moving said plasticizing cylinder out of said carrier block in the course of an axial releasing stroke of said fourth drive means and while said locking bolts are in said unlocking position;
• the improvement further comprising a stationarily held support component arranged for supporting said plasticizing cylinder after removal thereof from said carrier block by said fourth drive means;
• and a stationarily supported stopping device arranged to be brought into an abutting engagement with said plasticizing cylinder externally of said carrier block for stopping said plasticizing cylinder when being withdrawn from said injection mold assembly by said first drive means.