Continuous extrusion apparatus

Abstract

Continuous extrusion apparatus has a rotary extrusion wheel ( 11 ) fixed to the first end of a shaft ( 12 ) so as to rotate therewith about a rotary axis. The wheel ( 11 ) has at least one peripheral groove ( 19 ). A shoe extends around at least part of the wheel ( 11 ) and co-operates with the peripheral groove(s) ( 19 ) so as to define a passageway between the wheel ( 11 ) and the shoe. The passageway has an inlet for receipt of material to be extruded. The wheel ( 11 ) is rotatable relative to the shoe. An abutment member blocks the passageway so as to obstruct the passage of material. An extrusion die is disposed for receipt of material from the passageway. A mounting arrangement disposed between the wheel ( 11 ) and shaft ( 12 ) comprises a collet ( 43 ) having a first inner tapered surface ( 73 ) in abutment with a second inner tapered surface ( 63 ) defined by a hub ( 42 ) of the shaft ( 12 ). The wheel ( 11 ) has a first outer tapered surface ( 68 ) in abutment with a second outer tapered surface ( 61 ) defined by the hub ( 42 ).

1 . Continuous extrusion apparatus comprising:
 a shaft supported for rotation in a bearing, the shaft having first and second ends;   a rotary extrusion wheel fixed to the first end of the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove;   a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe;   an abutment member blocking the passageway so as to obstruct the passage of material;   an extrusion die disposed for receipt of material from the passageway;   a mounting arrangement disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel;   the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft.   
     
     
         2 . Continuous extrusion apparatus according to  claim 1 , wherein the first and second outer tapered surfaces extend outwards from the rotary axis and the first and second inner tapered surfaces extend inwards towards the rotary axis in the direction from the first to the second end of the shaft. 
     
     
         3 . Continuous extrusion apparatus according to  claim 2 , wherein the first and second outer tapered surfaces each at least partly define a frustoconical surface that is inclined at an angle of substantially 16° to the rotary axis. 
     
     
         4 . Continuous extrusion apparatus according to  claim 2 , wherein the first and second inner tapered surfaces each at least partly define a frustoconical surface that is inclined at an angle of substantially 16° to the rotary axis. 
     
     
         5 . Continuous extrusion apparatus according to  claim 1 , wherein the mounting member comprises a collet that is disposed substantially coaxially with the shaft and wheel. 
     
     
         6 . Continuous extrusion apparatus according to  claim 5 , wherein the collet has an external surface of substantially constant diameter and an internal surface that defines said first inner tapered surface. 
     
     
         7 . Continuous extrusion apparatus according to  claim 5  or  6 , wherein relative movement of the first and second inner tapered surfaces in the axial direction urges the collet radially outwards. 
     
     
         8 . Continuous extrusion apparatus according to  claim 7 , wherein an external surface of the collet bears against an internal surface defined by a bore in the wheel. 
     
     
         9 . Continuous extrusion apparatus according to  claim 5 , wherein the collet is radially resilient. 
     
     
         10 . Continuous extrusion apparatus according to  claim 9 , wherein the collet is penetrated by a plurality of slots that extend in a substantially axial direction from at least one end of the collet. 
     
     
         11 . Continuous extrusion apparatus according to  claim 10 , wherein the slots comprise a first group of slots and a second group of slots, the first group of slots being angularly spaced relative to one another and extending in a substantially axial direction from a first end of the collet and the second group of slots being angularly spaced relative to one another and extending in a substantially axial direction from a second end of the collet, the first group of slots being angularly offset from the second group of slots. 
     
     
         12 . Continuous extrusion apparatus according to  claim 1 , the mounting arrangement further comprising a hub fixed to the shaft. 
     
     
         13 . Continuous extrusion apparatus according to  claim 12 , wherein the hub defines the second outer tapered surface. 
     
     
         14 . Continuous extrusion apparatus according to  claim 13 , wherein the second outer tapered surface is defined by a projection on the hub. 
     
     
         15 . Continuous extrusion apparatus according to  claim 14 , wherein the projection is substantially annular. 
     
     
         16 . Continuous extrusion apparatus according to  claim 12 , wherein the second inner tapered surface is defined by the hub. 
     
     
         17 . Continuous extrusion apparatus according to  claim 16 , wherein the second inner tapered surfaced is defined by a frustoconical portion of the hub. 
     
     
         18 . Continuous extrusion apparatus according to  claim 12 , wherein the mounting arrangement further comprises a clamping ring for clamping the wheel to hub, the clamping ring and the wheel being supported on a plurality of fixing members. 
     
     
         19 . Continuous extrusion apparatus according to  claim 1 , wherein the mounting arrangement further comprises a clamping nut for clamping the mounting member in an axial direction. 
     
     
         20 . Continuous extrusion apparatus according to  claim 1 , wherein at least a portion of the mounting assembly is disposed within the bearing. 
     
     
         21 . Continuous extrusion apparatus according to  claim 12 , wherein the bearing is supported on an external surface of the hub. 
     
     
         22 . Continuous extrusion apparatus according to  claim 20 , further comprising a lubricant seal for the bearing, the seal being disposed around the mounting assembly. 
     
     
         23 . Continuous extrusion apparatus according to  claim 1 , wherein the bearing is supported in a wall, the wheel being disposed on one side of the wall and a bearing lubrication reservoir being disposed on the other side of the wall. 
     
     
         24 . Continuous extrusion apparatus according to  claim 1 , wherein the bearing is disposed at a distance from the rotary axis that is greater than the distance of the wheel from the rotary axis. 
     
     
         25 . Continuous extrusion apparatus according to  claim 1 , wherein a second end of the shaft is connected to a drive. 
     
     
         26 . Continuous extrusion apparatus according to  claim 1 , wherein there is provided a cooling chamber between the shaft and the mounting arrangement. 
     
     
         27 . Continuous extrusion apparatus according to  claim 26 , wherein the shaft has an internal bore in fluid communication with the cooling chamber. 
     
     
         28 . A method of use of a continuous extrusion apparatus comprising a shaft supported for rotation in a bearing, the shaft having first and second ends;
 a rotary extrusion wheel fixed to the first end of the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove;   a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe;   an abutment member blocking the passageway so as to obstruct the passage of material;   an extrusion die disposed for receipt of material from the passageway;   a mounting arrangement disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel;   the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft;   the method comprising rotating the extrusion wheel such that material is urged through the passageway, said material being compressed against the abutment member such that it yields and passes to the extrusion die.   
     
     
         29 . A method of manufacture of an extruded product comprising rotating an extrusion wheel relative to a shoe, that extends around at least part of the wheel and co-operates with at least one peripheral groove in the wheel so as to define a passageway between the wheel and the shoe, wherein the extrusion wheel is mounted onto a shaft by a mounting arrangement disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel, the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft, wherein the extrusion wheel is rotated relative to the shoe such that the material is urged through the passageway, said material being compressed against an abutment member blocking the passageway such that it yields and passes to an extrusion die; 
     
     
         30 . An extruded product made by the method of  claim 29 .