Nozzle shut-off device

Abstract

In an injection molding apparatus, wherein a plasticizing chamber has a nozzle attached to one end thereof, with the nozzle having a passageway therein and being in communication with the sprue of a mold, the improvement which constitutes a compact, pneumatically-powered, reciprocable spool-type device having a passageway therein, operated by alternately actuated opposed pistons, interposed between the nozzle and the plasticizing chamber, in one position blocking the communication between the plasticizing chamber and the nozzle and in the other position allowing molten material to enter the nozzle.

What is claimed is:  .[. 
     
       1.  In an injection molding apparatus comprising a chamber having a nozzle attached near one end thereof, means for forcing molten material from said chamber through a passageway formed in said nozzle, a mold having a sprue formed therein, which sprue is in communication with the passageway formed in said nozzle, and a nozzle shut-off device interposed between said nozzle and said chamber the improvement comprising: (a) a body for said device having a first passageway in communication with both said chamber and the passageway formed in said nozzle and a second passageway intersecting said first passageway;   (b) a spool reciprocal in the second passageway of said body and having a third passageway capable of communicating with the first passageway of said body;   (c) a piston attached to each end of said spool;   (d) a cylinder encompassing each of said pistons, said cylinders each having a closed end and an open end, with said open end being adjacent to said body and said cylinders being attached to said body;   (e) a source of fluid pressure; and   (f) means to connect said source of fluid pressure alternately to said cylinders to pressurize one and vent the other of said cylinders, thus causing said spool to reciprocate, thereby in one position blocking the first passageway in said body and in the other position connecting the third passageway in said spool with the first passageway in said body, thus allowing molten material to pass from said chamber into said nozzle..]. .[.2. In an injection molding apparatus comprising a plasticizing cylinder having a nozzle attached near one end thereof, means for forcing molten material from said cylinder through a passageway formed in said nozzle, a mold having a sprue formed therein, which sprue is in communication with said passageway formed in said nozzle, and valve means interposed between said nozzle and said cylinder the improvement comprising:   (a) a valve body having a first passageway in communication with said cylinder and in axial alignment with the passageway formed in said nozzle and a second passageway intersecting said first passageway;   (b) a valve spool reciprocable in the second passageway of said valve body and having a third passageway capable of axial alignment with the first passageway of said valve body;   (c) a piston attached to each end of said valve spool;   (d) a cylinder encompassing each of said pistons, said cylinders each having one closed end and one open end, with said open end being ajacent to said valve body and said cylinders each being attached to said valve body;   (e) a source of fluid under pressure; and   (f) means to connect said source of fluid under pressure alternately to said cylinders to pressurize one and vent the other of said cylinders, thereby causing said pistons and valve spool to reciprocate, thus in one position blocking the first passageway in said valve body and in the other position axially aligning the third passageway in said valvespool with the first passageway in said valve body, thereupon allowing molten material to enter said nozzle from said plasticizing cylinder..].  .[.3. In an injection molding apparatus comprising a temperature controllable cylinder having a nozzle attached to one end thereof, means for forcing molten material from said cylinder through a passageway formed in said nozzle, a platen with a mold having a sprue formed therein, which sprue is in communication with said passageway formed in said nozzle, and a nozzle shut-off valve interposed between said nozzle and said chamber, the improvement comprising:   (a) a valve body having a first passageway in axial alignment with both said cylinder and the passageway formed in said nozzle and a second passageway intersecting said first passageway;   (b) a valve spool reciprocable in the second passageway of said valve body and having a third passageway parallel to and capable of axial alignment with the first passageway of said valve body;   (c) a piston attached in an axial direction to each end of said valve spool;   (d) a cylinder peripherally encompassing each of said pistons and having one closed end and one open end with said open end being adjacent to said valve body and said cylinders each being attached to said valve body;   (e) a source of fluid under pressure; and   (f) means to connect said source of fluid under pressure alternately to said cylinders, to pressurize one and vent the other of said cylinders, thereby causing said pistons and valve spool to reciprocate in unison, thus in one position blocking the first passageway in said valve body and in the other position axially aligning the third passageway in said valve spool with the first passageway in said valve body, thereupon allowing molten material to enter said nozzle from said temperature controllable   
     
     
        cylinder..]. 4. The injection molding apparatus of claim .[.3.]. .Iadd.11 .Iaddend.wherein the second passageway in said valve body is substantially 
     
     
        perpendicular to the first passageway in said valve body. 5. The injection molding apparatus of claim .[.3.]. .Iadd.11 .Iaddend.wherein the second passageway of said valve body and said valve spool are substantially circular in cross-section and of substantially equal diameters.  .[.6. The injection molding apparatus of claim 3 with the addition of a piston-stroke adjusting means incorporated in at least one of said 
     
     
        cylinders..]. 7. The injection molding apparatus of claim 11 wherein the piston-stroke adjusting means comprises a nut and bolt assembly 
     
     
        incorporated in the closed end of at least one of said cylinders. 8. The injection molding apparatus of claim .[.3.]. .Iadd.11 .Iaddend.wherein the fluid under pressure which causes said pistons and valve spool to reciprocate is air.  .[.9. The injection molding apparatus of claim 3 wherein said nozzle shut-off valve in addition to being interposed between said nozzle and said cylinder is also substantially contained within a 
     
     
        recess in said platen..]. 10. The injection molding apparatus of claim .[.3.]. .Iadd.11 .Iaddend.with the addition of at least one internal 
     
     
        heating element incorporated into said valve body. .Iadd.11.  In an injection molding apparatus comprising a temperature controllable cylinder having a nozzle attached to one end thereof, means for forcing molten material from said cylinder through a passageway formed in said nozzle, a platen with a mold having a sprue formed therein, which sprue is in communication with said passageway formed in said nozzle, and a nozzle shut-off valve interposed between said nozzle and said cylinder, the improvement comprising: (a) a valve body having a first passageway in axial alignment with both said cylinder and the passageway formed in said nozzle and a second passageway intersecting said first passageway;   (b) a valve spool reciprocable in the second passageway of said valve body and having a third passageway parallel to and capable of axial alignment with the first passageway of said valve body;   (c) a piston attached in an axial direction to each end of said valve spool;   (d) a cylinder peripherally encompassing each of said pistons and having one closed end and one open end with said open end being adjacent to said valve body and said cylinders each being attached to said valve body;   (e) a piston-stroke adjusting means incorporated in at least one of said cylinders;   (f) a source of fluid under pressure; and   (g) means to connect said source of fluid under pressure alternately to said cylinders, to pressurize one and vent the other of said cylinders, thereby causing said pistons and valve spool to reciprocate in unison, thus in one position blocking the first passageway in said valve body and in the other position axially aligning the third passageway in said valve spool with the first passageway in said valve body, thereupon allowing molten material to enter said nozzle from said temperature controllable   
     
     
        cylinder. .Iaddend. .Iadd.12.  In an injection molding apparatus comprising a temperature controllable cylinder having a nozzle attached to one end thereof, means for forcing molten material from said cylinder through a passageway formed in said nozzle, a platen with a mold having a sprue formed therein, which sprue is in communication with said passageway formed in said nozzle, and a nozzle shut-off valve interposed between said nozzle and said cylinder, the improvement comprising: (a) a valve body having a first passageway in axial alignment with both said cylinder and the passageway formed in said nozzle and a second passageway intersecting said first passageway;   (b) a valve spool reciprocable in the second passageway of said valve body and having a third passageway parallel to and capable of axial alignment with the first passageway of said valve body;   (c) a piston attached in an axial direction to each end of said valve spool;   (d) a cylinder peripherally encompassing each of said pistons and having one closed end and one open end with said open end being adjacent to said valve body and said cylinders each being attached to said valve body;   (e) said platen having a recess therein located and sized to substantially contain said nozzle shut-off valve;   (f) said nozzle shut-off valve being disposed substantially within said recess;   (g) a source of fluid under pressure; and   (h) means to connect said source of fluid under pressure alternately to said cylinders, to pressurize one and vent the other of said cylinders, thereby causing said pistons and valve spool to reciprocate in unison, thus in one position blocking the first passageway in said valve body and in the other position axially aligning the third passageway in said valve spool with the first passageway in said valve body, thereupon allowing molten material to enter said nozzle from said temperature controllable cylinder. .Iaddend.