Device for manufacturing a plastic tube

Claim 1

A device for manufacturing a hollow tubular member having transverse or helical grooves on its exterior surface which comprises: at least one extruder having an annular mouthpiece; at least two semi-tubular die halves each having a portion of a desired profile corresponding to a portion of said grooves to be formed in said tubular members on its concave surface, said die halves cooperate with each other to form a hollow tubular die having a desired profile on its interior surface corresponding to said grooves to be formed in said tubular member, said die halves being movable relative to each other in opposite directions perpendicular to a longitudinal centerline of said die to allow said die halves to engage and disengage said tubular member, said die being disposed adjacent said annular mouthpiece of said extruder such that said longitudinal centerline of said die formed by said die halves is in line with a longitudinal centerline of said annular mouthpiece; said two semi-tubular die halves being movable in a longitudinal direction with said tubular member; means for generating a pressure differential between the interior and exterior of said tubular member when said tubular member is in the mold cavity formed by said die halves, the interior of said tubular member being under a higher pressure than the exterior thereof to force the tubular member outwardly into said desired profile of said die halves; and means for limiting said pressure differential between the exterior and interior of said tubular member so that the newly extruded tube will not be subjected to said pressure differential between the exterior and interior of said tubular member, said limiting means being movable with said tubular member during cooperation of said die halves.

Claim 2

A device for manufacturing a hollow tubular member having transverse or helical grooves on its exterior surface which comprises: at least one extruder having an annular mouthpiece; at least two semi-tubular die halves each having a portion of a desired profile corresponding to a portion of said grooves to be formed in said tubular members on its concave surface, said die halves cooperate with each other to form a hollow tubular die having a desired profile on its interior surface corresponding to said grooves to be formed in said tubular member, said die halves being movable relative to each other in opposite directions perpendicular to a longitudinal centerline of said die to allow said die halves to engage and disengage said tubular member, said die being disposed adjacent said annular mouthpiece of said extruder such that said longitudinal centerline of said die formed by said die halves is in line with a longitudinal centerline of said annular mouthpiece; said two semi-tubular die halves being movable in a longitudinal direction with said tubular member; means for generating a pressure differential between the interior and exterior of said tubular member when said tubular member is in the mold cavity formed by said die halves, the interior of said tubular member being under a higher pressure than the exterior thereof to force the tubular member outwardly into said desired profile of said die halves; and means for limiting said pressure differential between the exterior and interior of said tubular member so that the newly extruded tube will not be subjected to said pressure differential between the exterior and interior of said tubular member, said limiting means being movable with said tubular member during cooperation of said die halves.

Claim 3

A device for manufacturing a hollow tubular member having transverse or helical grooves on its exterior surface which comprises: at least one extruder having an annular mouthpiece; at least two semi-tubular die halves each having a portion of a desired profile corresponding to a portion of said grooves to be formed in said tubular members on its concave surface, said die halves cooperate with each other to form a hollow tubular die having a desired profile on its interior surface corresponding to said grooves to be formed in said tubular member, said die halves being movable relative to each other in opposite directions perpendicular to a longitudinal centerline of said die to allow said die halves to engage and disengage said tubular member, said die being disposed adjacent said annular mouthpiece of said extruder such that said longitudinal centerline of said die formed by said die halves is in line with a longitudinal centerline of said annular mouthpiece; a hollow rod disposed along said longitudinal centerline of said die and extending through said annular Mouthpiece of said extruder being movable along said longitudinal centerline of said die; a movable hollow member having at least two spaced apart fastening plates and a cylindrical inflatable wall situated therebetween concentrically disposed around said hollow rod located interior to and concentrically with said hollow tubular die spaced apart from said interior surface of said die to allow said tubular member to be inserted in said die between said interior surface of said die and said wall; a source of compressed air; a vacuum pump; a valve connected to said source of compressed air and said vacuum pump; a hose operatively connecting said valve to said source of compressed air and said vacuum pump; means to actuate said valve such that at the start of the operation said hose is operatively connected to said source of compressed air allowing said compressed air to flow into said moveable hollow member thereby inflating said hollow member and forcing said cylindrical inflatable wall outwardly towards said die thus forcing a portion of said tubular member situated between said wall and said die into said profiles in said interior surface of said die, and at the end of the operation to operatively connect said hose to said vacuum pump thus allowing said hollow member to be evacuated causing said inflatable wall to move inwardly away from said die and said tubular member disposed therein.

Claim 4

A device for manufacturing a hollow tubular member having transverse or helical grooves on its exterior surface which comprises: at least one extruder having an annular mouthpiece; at least two semi-tubular die halves each having a portion of a desired profile corresponding to a portion of said grooves to be formed in said tubular members on its concave surface, said die halves cooperate with each other to form a hollow tubular die having a desired profile on its interior surface corresponding to said grooves to be formed in said tubular member, said die halves being movable relative to each other in opposite directions perpendicular to a longitudinal centerline of said die to allow said die halves to engage and disengage said tubular member, said die being disposed adjacent said annular mouthpiece of said extruder such that said longitudinal centerline of said die formed by said die halves is in line with a longitudinal centerline of said annular mouthpiece; a hollow rod disposed along said longitudinal centerline of said die and extending through said annular Mouthpiece of said extruder being movable along said longitudinal centerline of said die; a movable hollow member having at least two spaced apart fastening plates and a cylindrical inflatable wall situated therebetween concentrically disposed around said hollow rod located interior to and concentrically with said hollow tubular die spaced apart from said interior surface of said die to allow said tubular member to be inserted in said die between said interior surface of said die and said wall; a source of compressed air; a vacuum pump; a valve connected to said source of compressed air and said vacuum pump; a hose operatively connecting said valve to said source of compressed air and said vacuum pump; means to actuate said valve such that at the start of the operation said hose is operatively connected to said source of compressed air allowing said compressed air to flow into said moveable hollow member thereby inflating said hollow member and forcing said cylindrical inflatable wall outwardly towards said die thus forcing a portion of said tubular member situated between said wall and said die into said profiles in said interior surface of said die, and at the end of the operation to operatively connect said hose to said vacuum pump thus allowing said hollow member to be evacuated causing said inflatable wall to move inwardly away from said die and said tubular member disposed therein.

Claim 6

A device for manufacturing a hollow tubular member having transverse or helical grooves on its exterior surface which comprises: at least one extruder having an annular mouthpiece; at least two semi-tubular die halves each having a portion of a desired profile corresponding to a portion of said grooves to be formed in said tubular members on its concave surface, said die halves cooperate with each other to form a hollow tubular die having a desired profile on its interior surface corresponding to said grooves to be formed in said tubular member, said die halves being movable relative to each other in opposite directions perpendicular to a longitudinal centerline of said die to allow said die halves to engage and disengage said tubular member, said die being disposed adjacent said annular mouthpiece of said extractor such that said longitudinal centerline of said die formed by said die halves is in line with a longitudinal centerline of said annular mouthpiece; a supporting rod disposed on said longitudinal centerline of said die and said longitudinal centerline of said annular mouthpiece of said extruder movable along said centerlines of said die and said annular mouthpiece; means defining a bore extending through said supporting rod along a longitudinal centerline of said rod; a movable inflator member affixed to said supporting rod for movement therewith having at least two spaced apart closing discs, a hollow cylinder disposed between said closing discs concentric with said supporting rod, said tubular member, said hollow cylinder and said closing discs cooperating to define a closed space, an outlet for a pressure medium from said hollow cylinder to said closed space situated in said hollow cylinder between said spaced apart closing discs, and means defininG a bore extending through one of said closing discs most remote from said annular mouthpiece of said extruder, said bore operatively communicating with the interior of said hollow cylinder and the exterior of said device; a hose operatively connecting said bore through said closing disc to said bore through said supporting rod; means to supply a pressure medium to said interior of said hollow cylinder operatively associated with an end of said bore in said support rod opposite said end thereof which is operatively connected to said hose; means to exhaust said pressure medium from said interior of said hollow cylinder operatively associated with said end of said bore in said support rod opposite said end thereof which is operatively connected with said hose; means to limit the longitudinal movement of said support rod and said inflator member along said centerlines of said die and said annular mouthpiece of said extruder; means for returning said movable inflator member along said centerline of said die and said annular mouthpiece of said extruder from a final operational position to a beginning operational position; means defining a bore extending through a portion of said annular mouthpiece of said extruder operatively associated at one end with a space defined by said closing discs disposed nearest said annular mouthpiece of said extruder, said annular mouthpiece of said extruder, and a portion of said tubular member situated between said extruder and said die, and at the other end with the exterior of the device to allow any inflating medium which may be trapped in said space to escape to the exterior of said device thus preventing a distortion of said portion of said tubular member between said extruder and said die; an adjustable pressure regulating means disposed in said outlet; said means to supply a pressure medium to said interior of said hollow cylinder supplies a pressure medium through said bore in said supporting rod, through said hose, and through said bore in one of said closing discs to said interior of said hollow cylinder, wherein the pressure exerted by said compression medium is confined until said pressure reaches a pressure which will cause said adjustable pressure regulating means to open allowing said compression medium to escape into said space defined by said hollow cylinder, said closing discs and said tubular member thereby exerting a force generally outwardly toward said die thus forcing a portion of said tubular member situated between said closing discs into said profile in said interior surface of said die, and after said tubular member is forced outwardly into said profiles in said interior surface of said die said means to exhaust said pressure medium from said hollow cylinder removes said pressure from said closed space through said adjustable pressure regulating means disposed in said outlet situated in said hollow cylinder, and any of said pressure medium which may have escaped from said closed space into said space defined by said annular mouthpiece, said closing disc nearest said annular mouth piece and said portion of said tubular member situated between said extruder and said die is allowed to escape through said bore extending through said portion of said annular mouthpiece of said extruder to the exterior of said device.

Claim 7

A device for manufacturing a hollow tubular member having transverse or helical grooves on its exterior surface which comprises: at least one extruder having an annular mouthpiece; at least two semi-tubular die halves each having a portion of a desired profile corresponding to a portion of said grooves to be formed in said tubular members on its concave surface, said die halves cooperate with each other to form a hollow tubular die having a desired profile on its interior surface corresponding to said grooves to be formed in said tubular member, said die halves being movable relative to each other in opposite directions perpendicular to a longitudinal centerline of said die to allow said die halves to engage and disengage said tubular member, said die being disposed adjacent said annular mouthpiece of said extractor such that said longitudinal centerline of said die formed by said die halves is in line with a longitudinal centerline of said annular mouthpiece; a supporting rod disposed on said longitudinal centerline of said die and said longitudinal centerline of said annular mouthpiece of said extruder movable along said centerlines of said die and said annular mouthpiece; means defining a bore extending through said supporting rod along a longitudinal centerline of said rod; a movable inflator member affixed to said supporting rod for movement therewith having at least two spaced apart closing discs, a hollow cylinder disposed between said closing discs concentric with said supporting rod, said tubular member, said hollow cylinder and said closing discs cooperating to define a closed space, an outlet for a pressure medium from said hollow cylinder to said closed space situated in said hollow cylinder between said spaced apart closing discs, and means defininG a bore extending through one of said closing discs most remote from said annular mouthpiece of said extruder, said bore operatively communicating with the interior of said hollow cylinder and the exterior of said device; a hose operatively connecting said bore through said closing disc to said bore through said supporting rod; means to supply a pressure medium to said interior of said hollow cylinder operatively associated with an end of said bore in said support rod opposite said end thereof which is operatively connected to said hose; means to exhaust said pressure medium from said interior of said hollow cylinder operatively associated with said end of said bore in said support rod opposite said end thereof which is operatively connected with said hose; means to limit the longitudinal movement of said support rod and said inflator member along said centerlines of said die and said annular mouthpiece of said extruder; means for returning said movable inflator member along said centerline of said die and said annular mouthpiece of said extruder from a final operational position to a beginning operational position; means defining a bore extending through a portion of said annular mouthpiece of said extruder operatively associated at one end with a space defined by said closing discs disposed nearest said annular mouthpiece of said extruder, said annular mouthpiece of said extruder, and a portion of said tubular member situated between said extruder and said die, and at the other end with the exterior of the device to allow any inflating medium which may be trapped in said space to escape to the exterior of said device thus preventing a distortion of said portion of said tubular member between said extruder and said die; an adjustable pressure regulating means disposed in said outlet; said means to supply a pressure medium to said interior of said hollow cylinder supplies a pressure medium through said bore in said supporting rod, through said hose, and through said bore in one of said closing discs to said interior of said hollow cylinder, wherein the pressure exerted by said compression medium is confined until said pressure reaches a pressure which will cause said adjustable pressure regulating means to open allowing said compression medium to escape into said space defined by said hollow cylinder, said closing discs and said tubular member thereby exerting a force generally outwardly toward said die thus forcing a portion of said tubular member situated between said closing discs into said profile in said interior surface of said die, and after said tubular member is forced outwardly into said profiles in said interior surface of said die said means to exhaust said pressure medium from said hollow cylinder removes said pressure from said closed space through said adjustable pressure regulating means disposed in said outlet situated in said hollow cylinder, and any of said pressure medium which may have escaped from said closed space into said space defined by said annular mouthpiece, said closing disc nearest said annular mouth piece and said portion of said tubular member situated between said extruder and said die is allowed to escape through said bore extending through said portion of said annular mouthpiece of said extruder to the exterior of said device.