Coupling device for an exchangeable working unit in an injection molding machine

An injection molding machine, having an axis of injection, comprising

• (a) a working unit adapted to be automatically exchanged as a whole and arranged for removal from and introduction into the machine in a direction transverse to said axis;
• said working unit including
• (1) an injection mold assembly;
• and
• (2) a plasticizing unit including a plasticizing cylinder and a feed screw received in said plasticizing cylinder and arranged for a rotary motion and an axial shifting motion relative to said plasticizing cylinder;
• said feed screw having a working position coaxial with said axis of injection;
• (b) a drive means for imparting a rotation and a periodic axial shifting motion to said feed screw;
• said drive means including a spindle oriented coaxially with said axis of injection;
• (c) a coupling means for operatively connecting said feed screw to and disconnecting it from said spindle;
• said coupling means including
• (1) a bolt housing connected to said spindle for rotation coaxially with said axis of injection;
• (2) locking bolts received in said bolt housing and arranged diametrically relative to said axis of injection;
• said locking bolts being radially displaceable into a locking position and a releasing position;
• (3) a radial clearance defined between said locking bolts;
• (4) spring means connected to said locking bolts for urging said locking bolts into said locking position thereof;
• (5) a radially guided expander wedge cooperating with said locking bolts and having a working position in which said expander wedge is advanced in said radial clearance, driving said locking bolts away from one another by camming action into said releasing position against a force of said spring means;
• (6) a radially oriented piston-and-cylinder unit connected to said expander wedge for moving said expander wedge into the working position thereof;
• said piston-and-cylinder unit having a radial working direction;
• (7) an axially displaceable radial coupling having a working position;
• (8) a coupling component forming a fixed part of said feed screw;
• said coupling component having
• (i) a circumferential groove being coaxial with said axis of injection in the working position of said feed screw;
• said locking bolts projecting into said circumferential groove in said locking position thereof for axially immobilizing said feed screw relative to said spindle;
• and
• (ii) a radial recess arranged for receiving said radial coupling in the working position thereof for torque-transmittingly connecting said feed screw with said spindle;
• and
• (d) an orienting means for stopping a common rotation of said bolt housing and said radial coupling in a desired angular position of said clearance in which said clearance is oriented parallel to said working direction of said radially oriented piston-and-cylinder unit.