Shear control for extruder apparatus

Claim 2

Apparatus for extruding plastic material comprising barrel means having inlet means for receiving material to be extruded and outlet means for exit of the material; screw means disposed in said barrel means and including an elongate body extending longitudinally in said barrel means and a helical rib extending around said body; drive means including motor means and reducer means coupled with and rotatably driven by said motor means and having output means driven at a speed less than the speed of said motor means; and shear control means coupling said output means of said reducer means with said screw means to rotate said screw means to force the material to be extruded from said inlet means to said outlet means of said barrel, said shear control means including a coupling shaft having a portion of reduced cross-sectional area to control the breaking point of said coupling shaft, said portion of reduced cross-sectional area of said coupling shaft having a cross-sectional area less than the cross-sectional area of said body of said screw means such that said coupling shaft will break at said portion of reduced cross-sectional area to interrupt rotation of said screw means when the shear force between said screw means and said output means of said reducer means exceeds a predetermined value less than the shear force required to break said screw means.

Claim 3

Apparatus for extruding materials as recited in claim 1 wherein the cross-sectional area of said portion of reduced cross-sectional area of said coupling shaft is less than the cross-sectional area at any point along said screw means.

Claim 4

Apparatus for extruding materials as recited in claim 1, wherein said output means of said reducer means includes a driving coupling member and said drive means includes a driven coupling member engaging said screw means, and said coupling shaft of said shear control means couples said driving coupling member and said driven coupling member.

Claim 5

Apparatus for extruding materials as recited in claim 1, wherein said shear control means includes a coupling shaft made of the same material as said screw means.

Claim 6

Apparatus for extruding materials as recited in claim 1, wherein said shear control means includes a coupling shaft made of a different material than said screw means.

Claim 7

Apparatus for extruding material comprising barrel means having inlet means for receiving material to be extruded and outlet means for exit of the material; screw means disposed in said barrel means including a shank and an elongate body extending longitudinally in said barrel means and having a helical rib therearound; drive means including motor means, reducer means coupled with and rotatably driven by said motor means and having output means driven at a speed less than the speed of said motor means, and a driven coupling member engaging said shank of said screw means; and shear control means coupling said output means of said reducer means with said driven coupling member to rotate said screw means to force the material to be extruded from said inlet means to said outlet means of said barrel said shear control means including a coupling shaft engaging said driven coupling member and said output means of said reducer means and having a portion of reduced cross-sectional area with the cross-sectional area thereof being less than the cross-sectional area of said body of said screw means such that said coupling shaft will break at said portion of reduced cross-sectional area to interrupt rotation of said screw means when the shear force between said screw means and said output means of said reducer means exceeds a predetermined value less than the shear force required to break said screw means.

Claim 8

Apparatus for extruding material comprising barrel means having inlet means for receiving material to be extruded and outlet means for exit of the material; screw means disposed in said barrel means including a shank and an elongate body extending longitudinally in said barrel means and having a helical rib therearound; drive means including motor means, reducer means coupled with and rotatably driven by said motor means and having output means driven at a speed less than the speed of said motor means, and a driven coupling member engaging said shank of said screw means; and shear control means coupling said output means of said reducer means with said driven coupling member to rotate said screw means to force the material to be extruded from said inlet means to said outlet means of said barrel said shear control means including a coupling shaft engaging said driven coupling member and said output means of said reducer means and having a portion of reduced cross-sectional area with the cross-sectional area thereof being less than the cross-sectional area of said body of said screw means such that said coupling shaft will break at said portion of reduced cross-sectional area to interrupt rotation of said screw means when the shear force between said screw means and said output means of said reducer means exceeds a predetermined value less than the shear force required to break said screw means.

Claim 9

Apparatus for extruding materials as recited in claim 6, wherein said output means of said reducer means includes a drive output member and a driving coupling member axially spaced from said driven coupling member engaging said drive output member, and said coupling shaft has a portion engaging said driving coupling member and a portion engaging said driven coupling member, said portion of reduced cross-sectional area being disposed in the space between said driving coupling member and said driven coupling member.

Claim 10

Apparatus for extruding material comprising barrel means having inlet means for receiving material to be extruded and outlet means for exit of the material; screw means disposed in said barrel means; drive means including motor means, reducer means coupled with and rotatably driven by said motor means and having output means driven at a speed less than the speed of said motor means, a driven coupling member engaging said screw means, a housing, and bearing means rotatably mounting said output means of said reducer means in said housing, said driven coupling member extending through said output means of said reducer means and terminating at a flange external of said housing, said output means of said reducer means having a flange disposed externally of said housing between said driven coupling member flange and said housing; and shear control means coupling said output means of said reducer means with said driven coupling member to rotate saiD screw means to force the material to be extruded from said inlet means to said outlet means of said barrel, said shear control means including shear pins engaging said flange of said output means and said driven coupling member flange such that said shear pins will break to interrupt rotation of said screw means when the shear force between said screw means and said output means of said reducer means exceeds a predetermined value less than the shear force required to break said screw means.

Claim 11

Apparatus for extruding material comprising barrel means having inlet means for receiving material to be extruded and outlet means for exit of the material; screw means disposed in said barrel means; drive means including motor means, reducer means coupled with and rotatably driven by said motor means and having output means driven at a speed less than the speed of said motor means, a driven coupling member engaging said screw means, a housing, and bearing means rotatably mounting said output means of said reducer means in said housing, said driven coupling member extending through said output means of said reducer means and terminating at a flange external of said housing, said output means of said reducer means having a flange disposed externally of said housing between said driven coupling member flange and said housing; and shear control means coupling said output means of said reducer means with said driven coupling member to rotate saiD screw means to force the material to be extruded from said inlet means to said outlet means of said barrel, said shear control means including shear pins engaging said flange of said output means and said driven coupling member flange such that said shear pins will break to interrupt rotation of said screw means when the shear force between said screw means and said output means of said reducer means exceeds a predetermined value less than the shear force required to break said screw means.

Claim 12

Apparatus for extruding material comprising barrel means having inlet means for receiving material to be extruded and outlet means for exit of the material; screw means disposed in said barrel means; drive means including motor means, reducer means coupled with and rotatably driven by said motor means and having output means driven at a speed less than the speed of said motor means, a driven coupling member engaging said screw means, a housing, and bearing means rotatably mounting said output means of said reducer means in said housing, said driven coupling member extending through said output means of said reducer means and terminating at a flange external of said housing, said output means of said reducer means having a flange disposed externally of said housing between said driven coupling member flange and said housing; and shear control means coupling said output means of said reducer means with said driven coupling member to rotate said screw means to force the material to be extruded from said inlet means to said outlet means of said barrel, said shear control means coupling said flange of said output means and said driven coupling member flange being operative to interrupt rotation of said screw means when the shear force between said screw means and said output means of said output means of said reducer means exceeds a predetermined value less than the shear force required to break said screw means.

Claim 13

Apparatus for extruding material comprising barrel means having inlet means for receiving material to be extruded and outlet means for exit of the material; screw means disposed in said barrel means; drive means including motor means, reducer means coupled with and rotatably driven by said motor means and having output means driven at a speed less than the speed of said motor means, a driven coupling member engaging said screw means, a housing, and bearing means rotatably mounting said output means of said reducer means in said housing, said driven coupling member extending through said output means of said reducer means and terminating at a flange external of said housing, said output means of said reducer means having a flange disposed externally of said housing between said driven coupling member flange and said housing; and shear control means coupling said output means of said reducer means with said driven coupling member to rotate said screw means to force the material to be extruded from said inlet means to said outlet means of said barrel, said shear control means coupling said flange of said output means and said driven coupling member flange being operative to interrupt rotation of said screw means when the shear force between said screw means and said output means of said output means of said reducer means exceeds a predetermined value less than the shear force required to break said screw means.