Continuous extrusion apparatus

Abstract

Continuous extrusion apparatus has a rotary extrusion wheel fixed to the first end of a shaft so as to rotate therewith about a rotary axis. The wheel has at least one peripheral groove. A shoe extends around at least part of the wheel and co-operates with the peripheral groove(s) so as to define a passageway between the wheel and the shoe. The passageway has an inlet for receipt of material to be extruded. The wheel 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 and shaft comprises a collet having a first inner tapered surface in abutment with a second inner tapered surface defined by a hub of the shaft. The wheel has a first outer tapered surface in abutment with a second outer tapered surface defined by the hub. A feed abutment member is biased by at least one biasing member so as to compress the material passing to the peripheral groove(s) of the wheel. The shoe is mounted on an adjustable support assembly. A scraper blade is selectively engageable with the wheel. The shoe has a curved surface that has a shape that is substantially fixed and forms a close radial fit with a radially outer surface of the wheel.

1 . A continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, 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 feed abutment member arranged to urge the material provided from the feeder into the at least one peripheral groove of the rotary extrusion wheel, wherein the feed abutment member is biased by at least one biasing member so as to compress the material passing from the feeder to the at least one peripheral groove of the rotary extrusion wheel. 
     
     
         2 . A continuous extrusion apparatus according to  claim 1  wherein the at least one biasing member is arranged such that the feed abutment member is moved in the radial direction, relative to the wheel, with the at least one biasing member. 
     
     
         3 . A continuous extrusion apparatus according to  claim 2  wherein the feed abutment member is mounted to a support assembly that is connected to a housing of the apparatus by the at least one biasing member such that the support assembly is moved relative to the housing with the at least one biasing member. 
     
     
         4 . A continuous extrusion apparatus according to  claim 1  wherein the at least one biasing member is arranged such that the feed abutment member compresses the material, passing from the feeder to the at least one peripheral groove of the extrusion wheel, to a substantially uniform thickness. 
     
     
         5 . A continuous extrusion apparatus according to  claim 4  wherein the at least one biasing member is arranged to exert a biasing force on the abutment member that is linearly proportional to the displacement, or deformation, of the at least one biasing member caused by contact of the material with the abutment member. 
     
     
         6 . A continuous extrusion apparatus according to  claim 1  wherein the feed abutment member is arranged to compress material from the feeder between a surface of the feed abutment member and at least one surface of the rotary extrusion wheel that defines the at least one peripheral groove. 
     
     
         7 . A continuous extrusion apparatus according to  claim 1  wherein the at least one biasing member comprises a piston slidably received in a housing, the piston having an end surface, a chamber being defined between the end surface of the piston and an internal surface of a housing, the chamber containing a fluid that is compressed by the piston as the piston moves relative to the housing such that the volume of the chamber is reduced, thereby exerting a force on the piston. 
     
     
         8 . A continuous extrusion apparatus according to  claim 1  wherein the at least one biasing member comprises a resiliently deformable biasing member. 
     
     
         9 . A continuous extrusion apparatus according to  claim 1  wherein the feed abutment member is rotatably mounted to a housing of the continuous extrusion apparatus such that it rotates about an axis as it compresses said material from the feeder. 
     
     
         10 . A continuous extrusion apparatus according to  claim 9  wherein the axis of rotation of the feed abutment member is substantially parallel to the rotary axis of the extrusion wheel. 
     
     
         11 . A continuous extrusion apparatus according to  claim 9  wherein the feed abutment member is freely rotatable. 
     
     
         12 . A continuous extrusion apparatus according to  claim 9  wherein the feed abutment member has a substantially arcuate cross-sectional shape. 
     
     
         13 . A continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, 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, wherein the shoe is mounted to an adjustable support assembly for positioning the shoe relative to the wheel, the adjustable support assembly being arranged to adjust the position of the shoe relative to the wheel along first and second axes that are inclined relative to each other. 
     
     
         14 . A continuous extrusion apparatus according to  claim 13  wherein the adjustable support assembly is arranged such that the position of the shoe relative to the wheel may be varied along said first and second axes independently. 
     
     
         15 . A continuous extrusion apparatus according to  claim 13  wherein the adjustable support assembly comprises a first adjustment assembly that is moveable in said first axial direction relative to the shoe and is coupled to a housing such that as it moves in said first axial direction relative to the shoe it moves in said second axial direction and wherein the first adjustment assembly is coupled to the shoe such that as the first adjustment assembly moves in the second axial direction, the shoe is moved in said second axial direction and a second adjustment assembly that is moveable in said second axial direction relative to the shoe and is coupled to a housing such that as it moves in said second axial direction relative to the shoe it moves in said first axial direction and wherein the second adjustment assembly is coupled to the shoe such that as the second adjustment assembly moves in the first axial direction, the shoe is moved in said first axial direction. 
     
     
         16 . A continuous extrusion apparatus according to  claim 15  wherein the first and second adjustment assemblies are coupled to each other such that movement of the first adjustment assembly in the second axial direction does not move the second adjustment assembly in the second axial direction and movement of the second adjustment assembly in the first axial direction does not move the first adjustment assembly in the first axial direction. In this regard, optionally the first adjustment assembly is slidably mounted relative to the second adjustment assembly in the second axial direction and the second adjustment assembly is slidably mounted relative to the first adjustment assembly in the first axial direction. 
     
     
         17 . A continuous extrusion apparatus according to  claim 15  wherein the first adjustment assembly comprises a first adjustment member that is slidable in said first axial direction relative to the wheel and a coupling member that is fixedly attached to the first adjustment member, wherein the first formation is provided in, or on, the coupling member. 
     
     
         18 . A continuous extrusion apparatus according to  claim 17  wherein the first adjustment member comprises a platform having a first surface that is coupled to the shoe such that it is slidable relative to the shoe in the first axial direction but is substantially fixed relative to the shoe in the second axial direction and a second surface that is slidably engageable with a surface of a housing such that as it slides relative to the housing the platform is moved in the second axial direction. 
     
     
         19 . A continuous extrusion apparatus according to  claim 15  wherein the second adjustment assembly comprises a second adjustment member that is slidable in said second axial direction relative to the wheel and a coupling member that is fixedly attached to the second adjustment member, wherein the second formation is provided in, or on, the coupling member. 
     
     
         20 . A continuous extrusion apparatus according to  claim 19  wherein the second adjustment member comprises a platform having a first surface that is coupled to the shoe such that it is slidable relative to the shoe in the second axial direction but is substantially fixed relative to the shoe in the first axial direction and a second surface that is slidably engageable with a surface of a housing such that as it slides relative to the housing the platform is moved in the first axial direction. 
     
     
         21 . A continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, 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, wherein the apparatus further comprises a cutting member that is movable between a first position relative to the wheel in which it scrapes material from the wheel, as the wheel rotates, and a second position in which it is spaced further from the wheel than when it is in the first position. 
     
     
         22 . A continuous extrusion apparatus according to  claim 21  wherein when the cutting member is in the second position it does not scrape material from the wheel, as the wheel rotates. 
     
     
         23 . A continuous extrusion apparatus according to  claim 21  wherein when the cutting member is in the first position it abuts a radially peripheral surface of the wheel and when the cutting member is in the second position it is spaced from the radially peripheral surface of the wheel. 
     
     
         24 . A continuous extrusion apparatus according to  claim 22  wherein the cutting member is rotatably mounted to a housing of the apparatus such that it is rotatable between its first and second positions. 
     
     
         25 . A continuous extrusion apparatus according to  claim 22  wherein the cutting member has a cutting surface arranged such that when the cutting member is in the first position, the cutting surface scrapes material from the wheel, as the wheel rotates, the cutting surface extending substantially in a plane that is tangential to the radially outer periphery of the wheel, where the cutting surface contacts the wheel. 
     
     
         26 . A continuous extrusion apparatus according to  claim 25  wherein when the cutting member is in the first position, the cutting surface contacts the radially outer periphery of the wheel along a cutting line, the cutting line and the tangential direction of the outer peripheral surface of the wheel, along this line, defining a plane that is coplanar with the plane of the cutting surface. 
     
     
         27 . A continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel, wherein when the shoe is in a first position relative to the wheel a curved surface of the shoe co-operates 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, wherein the shoe is moveable between said first position and a second position relative to the wheel in which the curved surface of the wheel is spaced further from the wheel then when the shoe is in the first position and wherein the curved surface of the shoe has a shape that is substantially fixed and, when the shoe is in the first position, forms a close radial fit with a radially outer surface of the wheel. 
     
     
         28 . A continuous extrusion apparatus according to  claim 27  wherein the curved surface of the shoe has a diameter that is substantially the same as, or slightly greater than, the diameter of the radially outer surface of the wheel. 
     
     
         29 . A continuous extrusion apparatus according to  claim 27  wherein the shoe is mounted on a support that is mounted to a housing of the apparatus such that the shoe is movable between said first and second positions. 
     
     
         30 . A continuous extrusion apparatus according to  claim 27  wherein the shaft is supported for rotation in a bearing, the shaft having first and second ends; the rotary extrusion wheel is fixed to a first end of the shaft so as to rotate therewith about said rotary axis, a mounting arrangement is 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.