Title of Invention	"AN APPARATUS FOR CONTINUOUS EXTRUSION"
Abstract	A die top assembly (Fig 3) engaging with a rotating wheel (not shown) of a continuous extrusion apparatus includes a die top 22 formed with a part cylindrical face 34 co-acting with the wheel cylindrical surface and is positioned in a shoe 8 held in contact with the wheel. The die top 22, which is required to resist the very high extrusion pressure forces, is carried on a support block 30 and, at the face remote from the part cylindrical face 34, is formed with a recess 50 accommodating a die support ring 54 and spacer 52. Ports 28 registering with circumferential grooves in the rotating wheel extend from the part cylindrical face 34 to a semi-toroidal channel 44 and extrudate supply chamber 46 extending around a central boss 80. A central mandrel die piece 72 is secured in position by means of a bolt 76 threaded into a blind bore 78 in the boss 80 and co-acts with a cylindrical die 56 to form an extrusion orifice 86. By securing the die piece 72 by means of the bolt 76 threaded into the blind bore 78, the dimension radially of the die top 22 nay be reduced to a minimum by virtue of avoidance of weakening penetrations other than the ports 28 in the portion of the die top 22 adjoining the rotating wheel. This has the benefit that the axial extent of the ports 28 may be reduced to a minimum, thereby reducing to a minimum the frictional losses imposed on feed material extruded through the ports, an important consideration particularly when extruding copper. A range of cylindrical dies 56 and central mandrel die pieces 72 may be utilised without having to use a different die top, thereby increasing the versatility of the apparatus without incurring large additional expenditure for a complete set of tooling.

Title of Invention

"AN APPARATUS FOR CONTINUOUS EXTRUSION"

Abstract

A die top assembly (Fig 3) engaging with a rotating wheel (not shown) of a continuous extrusion apparatus includes a die top 22 formed with a part cylindrical face 34 co-acting with the wheel cylindrical surface and is positioned in a shoe 8 held in contact with the wheel. The die top 22, which is required to resist the very high extrusion pressure forces, is carried on a support block 30 and, at the face remote from the part cylindrical face 34, is formed with a recess 50 accommodating a die support ring 54 and spacer 52. Ports 28 registering with circumferential grooves in the rotating wheel extend from the part cylindrical face 34 to a semi-toroidal channel 44 and extrudate supply chamber 46 extending around a central boss 80. A central mandrel die piece 72 is secured in position by means of a bolt 76 threaded into a blind bore 78 in the boss 80 and co-acts with a cylindrical die 56 to form an extrusion orifice 86. By securing the die piece 72 by means of the bolt 76 threaded into the blind bore 78, the dimension radially of the die top 22 nay be reduced to a minimum by virtue of avoidance of weakening penetrations other than the ports 28 in the portion of the die top 22 adjoining the rotating wheel. This has the benefit that the axial extent of the ports 28 may be reduced to a minimum, thereby reducing to a minimum the frictional losses imposed on feed material extruded through the ports, an important consideration particularly when extruding copper. A range of cylindrical dies 56 and central mandrel die pieces 72 may be utilised without having to use a different die top, thereby increasing the versatility of the apparatus without incurring large additional expenditure for a complete set of tooling.

Full Text	This invention relates to an apparatus for continuous extrusion and generally to apparatus for the forming of metals by a continuous extrusion process in which feedstock is introduced into a circumferential groove in a rotating wheel to pass into a passageway formed between the groove and arcuate tooling extending into the groove. EP-A-071 490 discloses continuous extrusion apparatus having a rotatable wheel formed with a circumferential groove, arcuate tooling bounding a radially outer portion of the groove provided with an exit aperture in a die top and an abutment displaced in the direction of rotation from the exit aperture. According to the present invention the die top is formed with a part cylindrical face arranged to co-act with a portion of the cylindrical surface of the rotatable wheel and, remote from the part cylindrical face, a face having a central recess, extrusion mandrel die means are positioned in the recess with an extrudate supply chamber formed in the recess discharging directly to the extrusion mandrel die means with port means connecting the extrudate supply chamber to the circumferential groove in the rotatable wheel and an extrusion mandrel die piece is positioned centrally of the recess on a bolt threaded into the die top from the recess. Preferably, a boss is positioned centrally of the recess to receive the bolt and is formed with a frusto-conical seating co-acting with a corresponding face on the mandrel die piece to seat and centrally locate the mandrel die piece on the boss. Desirably a die support ring carrying a cylindrical die is positioned in the recess co-axially of the mandrel die piece to provide an extrusion orifice intermediate the cylindrical die and the mandrel die piece. Suitably, downstream of a surface portion bounding the extrusion orifice, the cylindrical die and the die support ring are formed with an outwardly diverging surface portion. Advantageously, the rotatable wheel is formed with a plurality of circumferential grooves. Where an even number of circumferential grooves is provided the recess may be positioned with a central axis intermediate the circumferential grooves. Thin-walled copper tubing may be produced using a copper feed stock and an annular extrusion orifice. Accordingly, there is provided an apparatus for continuous extrusion comprising a rotatable wheel formed with a circumferential groove, arcuate tooling bounding a radially outer portion of the groove provided with an exit aperture in a die top and an abutment displaced in the direction of rotation from the exit aperture, characterized in that the die top is formed with a part cylindrical face arranged to co-act with a portion of the cylindrical surface of the rotatable wheel and, remote from the part cylindrical face, a face having a central recess, extrusion mandrel die means are positioned in the recess with an extrudate supply chamber formed in the recess discharging directly to the extrusion mandrel die means with port means connecting the extrudate supply chamber to the circumferential groove in the rotatable wheel and an extrusion mandrel die piece is positioned centrally of the recess on a bolt threaded into the die top from the recess. The invention will now be described, by way of example, with reference to the accompanying, partly diagrammatic drawings, in which: Figure 1 is a cross-sectional side elevation of the continuous extrusion apparatus partly offset from a plane through one groove of a pair of grooves in a wheel to a plane extending centrally of the pair of grooves through an extrusion die, the offset section plane following the centre line of an exit aperture connecting the respective groove to the extrusion die; Figure 2 is a cross-sectional view, taken in plan, of a portion of the wheel and associated parts, along the plane indicated by the line II-II in Figure 1 and Figure 3; Figure 3 is a cross-sectional side elevation of parts associated with the extrusion die; Figure 4 is a plan view of a die top portion; and Figure 5 is a view of the die top portion taken from below. As shown in Figure 1 the continuous extrusion apparatus includes a circumferentially grooved wheel 2 mounted on a horizontal drive shaft 4 running on bearings (not shown) positioned on a bed (not shown) . Arcuate tooling 6 is positioned in a shoe 8 mounted on a pivot 10 extending parallel to the horizontal drive shaft 4 and urged against a stop 12 positioned adjacent the wheel 2 and above the drive shaft 4 by means of a main hydraulic ram 14 bearing against a shoulder 16 formed on the shoe. A support ram 18 is provided to pivot the shoe 8 into, or out of, registration with the wheel 2. The tooling 6 includes a shoe insert 20, a die top 22 and abutments 24 positioned in the shoe 8 to register with the wheel. The wheel 2 is formed with circumferential twin grooves 26 and the shoe insert 20 serves, when the shoe is in position adjacent the stop 12, to form a closure to the adjacent portion of the circumferential grooves 26 in the wheel as the wheel rotates past the shoe insert. The die top 22 forms a continuation of the shoe insert 20 and also forms a closure to the adjacent rotated portion of the circumferential grooves. The abutments 24 extend into the respective. circumferential grooves 26 to form an obturation of the grooves and cause displacement of feed material in the grooves through resspective exit apertures 28 to discharge to a die adapted to produce a required tubular extrusion product. As indicated to an enlarged scale in Figures 2,3,4 and 5, the die top 22 is attached to a support block 30 by bolts (not shown) and positioned in a stepped seating 32 in the shoe 8. A face 34 of the die top 22 remote from the support block 30 conforms to the twin grooved surface 36 of the wheel 2 and is of generally rectangular cross-section. Ports 44 extend from locations in the face 34 registering with the twin grooves 26 in the wheel 2 to a semi-toroidal channel 46 in an end face 48 of a central cylindrical recess 50 formed in the die top 22 adjacent the support block 30. The ports 44 are formed with a cross-section increasing toward the channel 46. A spacer 52 and a die support ring 54 carrying a cylindrical die 56 are positioned in the recess 50 co-axially of a central mandrel die piece 72 to form an annular extrusion orifice 86. The die support ring 54 and the cylindrical die 56 are formed with contiguous frusto-conical faces 62, 64 converging smoothly from the semi-toroidal channel outer periphery 66 to the cylindrical die circumferential edge 68. The cylindrical die 56 and die support ring 54 are flared outwardly from the circumferential edge 68 to an end face 70 of the die support ring seating cm the support block 30. The central mandrel die piece 72 and a spacer 74 are secured to the die top 22 by means of a bolt 76 threaded in to a blind bore 78 in a boss 30 co-axial of the semi-toroidal channel 46 tangentially continuous with a radially inner portion thereof. The die piece 72 is formed with a frusto-conical end face 82 (Fig.3) arranged to mate with a corresponding seating 84 on the boss 80 rigidly to locate the die piece on the boss. Since the die piece 72 is secured to the die top 22 by means of the bolt 76 threaded into the blind bore 78 from the face of the die top remote from the face 34 registering with the wheel 2, the dimension radially of the wheel of the die top 22 may be reduced to a minimum by virtue of avoidance of weakening penetrations other than the ports 44. This has the result that the axial extent of the ports 44 is reduced to a minimum, thereby reducing to a minimum frictional losses imposed on feed material extruded through the ports. The axes of the ports are aligned to minimise the distance between the grooves 26 and the extrusion orifice 86. Thus, in other embodiments, the axes of the ports may diverge from the central plane of the wheel 2. within the dimensional confines imposed by the outer diameter of the semi-toroidal channel 46 a range of cylindrical dies 56 and central mandrel die pieces 72 may be utilised without having to utilise a different die top 22, thereby increasing the versatility of the apparatus without incurring large additional expenditure for a complete set of tooling. Whilst it is intended that the hereinbefore described continuous extrusion apparatus has particular relevance to the production of thin-walled copper tube, it will be appreciated that other materials or cross-sections may be extruded with similar advantages. In a Situation in which the wheel 2 is provided with a single circumferential groove or an uneven number of circumferential grooves, the port 44 leading from the single groove or the central groove is bifurcated to extend past the bore 78 for the bolt 76. WE CLAIM: 1. An apparatus for continuous extrusion comprising a rotatable wheel (2) formed with a circumferential groove (26), arcuate tooling (6) bounding a radially outer portion of the groove provided with an exit aperture in a die top (22) and an abutment (24) displaced in the direction of rotation from the exit aperture, characterized in that the die top (22) is formed with a part cylindrical face (34) arranged to co-act with a portion of the cylindrical surface (36) of the rotatable wheel (2) and, remote from the part cylindrical face (34) , a face (70) having a central recess (50), extrusion mandrel die means (56) are positioned in the recess with an extrudate supply chamber (46) formed in the recess discharging directly to the extrusion mandrel die means (56) with port means (28) connecting the extrudate supply chamber (46) to the circumferential groove (26) in the rotatable wheel (2) and an extrusion mandrel die piece (72) is positioned centrally of the recess (50) on a bolt (76) threaded into the die top (22) from the recess (50). 2. The apparatus as claimed in claim 1, wherein a boss (80) is positioned centrally of the recess (50) to receive the bold (76) and is formed with a frusto-conical seating (84) co-acting with a corresponding face (82) on the mandrel die piece (72) to seat and centrally locate the mandrel die piece (72) on the post (80). 3. The apparatus as claimed in claim 1 or claim 2, wherein a die support ring (54) carrying a cylindrical die (56) is positioned in the recess (50) co-axially of the mandrel die piece (72) to provide an extrusion orifice (86) intermediate the cylindrical die (56) and the mandrel die piece (72). 4. The apparatus as claimed in claim 3, wherein downstream of a surface portion bounding the extrusion orifice (86), the cylindrical die (56) and the die support ring (54) are formed with outwardly diverging surface portions. 5. The apparatus as claimed in any preceding claim, wherein the rotatable wheel (2) is formed with a plurality of circumferential grooves (26). 6. The apparatus as claimed in claim 5, wherein the rotatable wheel (2) is formed with an even number of circumferential grooves (26) and the recess (50) is positioned with a central axis intermediate the circumferential grooves (26). 7. Thin-walled copper tubing produced in the apparatus as claimed in any preceding claim utilizing a copper feedstock and an annular extrusion orifice (86). 8. Continuous extrusion apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Full Text

This invention relates to an apparatus for continuous extrusion and generally to apparatus for the forming of metals by a continuous extrusion process in which feedstock is introduced into a circumferential groove in a rotating wheel to pass into a passageway formed between the groove and arcuate tooling extending into the groove.
EP-A-071 490 discloses continuous extrusion apparatus having a rotatable wheel formed with a circumferential groove, arcuate tooling bounding a radially outer portion of the groove provided with an exit aperture in a die top and an abutment displaced in the direction of rotation from the exit aperture.
According to the present invention the die top is formed with a part cylindrical face arranged to co-act with a portion of the cylindrical surface of the rotatable wheel and, remote from the part cylindrical face, a face having a central recess, extrusion mandrel die means are positioned in the recess with an extrudate supply chamber formed in the recess discharging directly to the extrusion mandrel die means with port means connecting the extrudate supply chamber to the circumferential groove in the rotatable wheel and an extrusion mandrel die piece is positioned centrally of the recess on a bolt threaded into the die top from the recess.
Preferably, a boss is positioned centrally of the recess to receive the bolt and is formed with a frusto-conical seating co-acting with a corresponding face on the mandrel die piece to seat and centrally locate the mandrel die piece on the boss.
Desirably a die support ring carrying a cylindrical die is positioned in the recess co-axially of the mandrel die piece to provide an extrusion orifice intermediate the cylindrical die and the mandrel die piece.

Suitably, downstream of a surface portion bounding the extrusion orifice, the cylindrical die and the die support ring are formed with an outwardly diverging surface portion.
Advantageously, the rotatable wheel is formed with a plurality of circumferential grooves. Where an even number of circumferential grooves is provided the recess may be positioned with a central axis intermediate the circumferential grooves.
Thin-walled copper tubing may be produced using a copper feed stock and an annular extrusion orifice.
Accordingly, there is provided an apparatus for continuous extrusion comprising a rotatable wheel formed with a circumferential groove, arcuate tooling bounding a radially outer portion of the groove provided with an exit aperture in a die top and an abutment displaced in the direction of rotation from the exit aperture, characterized in that the die top is formed with a part cylindrical face arranged to co-act with a portion of the cylindrical surface of the rotatable wheel and, remote from the part cylindrical face, a face having a central recess, extrusion mandrel die means are positioned in the recess with an extrudate supply chamber formed in the recess discharging directly to the extrusion mandrel die means with port means connecting the extrudate supply chamber to the circumferential groove in the rotatable wheel and an extrusion mandrel die piece is positioned centrally of the recess on a bolt threaded into the die top from the recess.
The invention will now be described, by way of example, with reference to the accompanying, partly diagrammatic drawings, in which:
Figure 1 is a cross-sectional side elevation of the continuous extrusion apparatus partly offset from a plane through one groove of a pair of grooves in a wheel to a plane extending centrally of the pair of grooves through an extrusion

die, the offset section plane following the centre line of an exit aperture connecting the respective groove to the extrusion die;
Figure 2 is a cross-sectional view, taken in plan, of a portion of the wheel and associated parts, along the plane indicated by the line II-II in Figure 1 and Figure 3;
Figure 3 is a cross-sectional side elevation of parts associated with the extrusion die;
Figure 4 is a plan view of a die top portion; and
Figure 5 is a view of the die top portion taken from below.
As shown in Figure 1 the continuous extrusion apparatus includes a circumferentially grooved wheel 2 mounted on a horizontal drive shaft 4 running on bearings (not shown) positioned on a bed (not shown) . Arcuate tooling 6 is positioned in a shoe 8 mounted on a pivot 10 extending parallel to the horizontal drive shaft 4 and urged against a stop 12 positioned adjacent the wheel 2 and above the drive shaft 4 by means of a main hydraulic ram 14 bearing against a shoulder 16 formed on the shoe. A support ram 18 is provided to pivot the shoe 8 into, or out of, registration with the wheel 2. The tooling 6 includes a shoe insert 20, a die top 22 and abutments 24 positioned in the shoe 8 to register with the wheel. The wheel 2 is formed with circumferential twin grooves 26 and the shoe insert 20 serves, when the shoe is in position adjacent the stop 12, to form a closure to the adjacent portion of the circumferential grooves 26 in the wheel as the wheel rotates past the shoe insert. The die top 22 forms a continuation of the shoe insert 20 and also forms a closure to the adjacent rotated portion of the circumferential grooves. The abutments 24 extend into the respective. circumferential grooves 26 to form an obturation of the grooves and cause displacement of feed material in the grooves through resspective exit apertures 28 to discharge to a die adapted to produce a required tubular extrusion product.
As indicated to an enlarged scale in Figures 2,3,4
and 5, the die top 22 is attached to a support block 30 by bolts (not shown) and positioned in a stepped seating 32 in the shoe 8. A face 34 of the die top 22 remote from the support block 30 conforms to the twin grooved surface 36 of the wheel 2 and is of generally rectangular cross-section. Ports 44 extend from locations in the face 34 registering with the twin grooves 26 in the wheel 2 to a semi-toroidal channel 46 in an end face 48 of a central cylindrical recess 50 formed in the die top 22 adjacent the support block 30. The ports 44 are formed with a cross-section increasing toward the channel 46. A spacer 52 and a die support ring 54 carrying a cylindrical die 56 are positioned in the recess 50 co-axially of a central mandrel die piece 72 to form an annular extrusion orifice 86. The die support ring 54 and the cylindrical die 56 are formed with contiguous frusto-conical faces 62, 64 converging smoothly from the semi-toroidal channel outer periphery 66 to the cylindrical die circumferential edge 68. The cylindrical die 56 and die support ring 54 are flared outwardly from the circumferential edge 68 to an end face 70 of the die support ring seating cm the support block 30.
The central mandrel die piece 72 and a spacer 74 are secured to the die top 22 by means of a bolt 76 threaded in to a blind bore 78 in a boss 30 co-axial of the semi-toroidal channel 46 tangentially continuous with a radially inner portion thereof. The die piece 72 is formed with a frusto-conical end face 82 (Fig.3) arranged to mate with a corresponding seating 84 on the boss 80 rigidly to locate the die piece on the boss. Since the die piece 72 is secured to the die top 22 by means of the bolt 76 threaded into the blind bore 78 from the face of the die top remote from the face 34 registering with the wheel 2, the dimension radially of the wheel of the die top 22 may be reduced to a minimum

by virtue of avoidance of weakening penetrations other than the ports 44. This has the result that the axial extent of the ports 44 is reduced to a minimum, thereby reducing to a minimum frictional losses imposed on feed material extruded through the ports. The axes of the ports are aligned to minimise the distance between the grooves 26 and the extrusion orifice 86. Thus, in other embodiments, the axes of the ports may diverge from the central plane of the wheel 2.
within the dimensional confines imposed by the outer diameter of the semi-toroidal channel 46 a range of cylindrical dies 56 and central mandrel die pieces 72 may be utilised without having to utilise a different die top 22, thereby increasing the versatility of the apparatus without incurring large additional expenditure for a complete set of tooling.
Whilst it is intended that the hereinbefore described continuous extrusion apparatus has particular relevance to the production of thin-walled copper tube, it will be appreciated that other materials or cross-sections may be extruded with similar advantages.
In a Situation in which the wheel 2 is provided with a single circumferential groove or an uneven number of circumferential grooves, the port 44 leading from the single groove or the central groove is bifurcated to extend past the bore 78 for the bolt 76.

WE CLAIM:
1. An apparatus for continuous extrusion comprising a rotatable wheel
(2) formed with a circumferential groove (26), arcuate tooling (6)
bounding a radially outer portion of the groove provided with an exit
aperture in a die top (22) and an abutment (24) displaced in the
direction of rotation from the exit aperture, characterized in that the die top (22) is
formed with a part cylindrical face (34) arranged to co-act with a
portion of the cylindrical surface (36) of the rotatable wheel (2) and,
remote from the part cylindrical face (34) , a face (70) having a central
recess (50), extrusion mandrel die means (56) are positioned in the
recess with an extrudate supply chamber (46) formed in the recess
discharging directly to the extrusion mandrel die means (56) with port
means (28) connecting the extrudate supply chamber (46) to the
circumferential groove (26) in the rotatable wheel (2) and an extrusion
mandrel die piece (72) is positioned centrally of the recess (50) on a
bolt (76) threaded into the die top (22) from the recess (50).
2. The apparatus as claimed in claim 1, wherein a boss (80) is positioned centrally of the recess (50) to receive the bold (76) and is formed with a frusto-conical seating (84) co-acting with a corresponding face (82) on the mandrel die piece (72) to seat and centrally locate the mandrel die piece (72) on the post (80).
3. The apparatus as claimed in claim 1 or claim 2, wherein a die support ring (54) carrying a cylindrical die (56) is positioned in the recess (50) co-axially of the mandrel die piece (72) to provide an extrusion orifice (86) intermediate the cylindrical die (56) and the mandrel die piece (72).

4. The apparatus as claimed in claim 3, wherein downstream of a surface portion bounding the extrusion orifice (86), the cylindrical die (56) and the die support ring (54) are formed with outwardly diverging surface portions.
5. The apparatus as claimed in any preceding claim, wherein the rotatable wheel (2) is formed with a plurality of circumferential grooves (26).
6. The apparatus as claimed in claim 5, wherein the rotatable wheel (2) is formed with an even number of circumferential grooves (26) and the recess (50) is positioned with a central axis intermediate the circumferential grooves (26).
7. Thin-walled copper tubing produced in the apparatus as claimed in any preceding claim utilizing a copper feedstock and an annular extrusion orifice (86).
8. Continuous extrusion apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

565-del-1996-abstract.pdf

565-del-1996-claims.pdf

565-del-1996-complete specification (granted).pdf

565-del-1996-correspondence-others.pdf

565-del-1996-correspondence-po.pdf

565-del-1996-description (complete).pdf

565-del-1996-drawings.pdf

565-del-1996-form-1.pdf

565-del-1996-form-13.pdf

565-del-1996-form-2.pdf

565-del-1996-form-3.pdf

565-del-1996-form-4.pdf

565-del-1996-form-6.pdf

565-del-1996-pa.pdf

565-del-1996-petition-137.pdf

565-del-1996-petition-138.pdf

« Previous Patent

Next Patent »

Patent Number

199494

Indian Patent Application Number

565/DEL/1996

PG Journal Number

37/2008

Publication Date

12-Sep-2008

Grant Date

09-Mar-2007

Date of Filing

18-Mar-1996

Name of Patentee

BWE LIMITED

Applicant Address

BEAVER ROAD INDUSTRIAL ESTATE, ASHFORD, KENT TN23 1SH, U.K.

Inventors:

#	Inventor's Name	Inventor's Address
1	EDWARD PURVIS CARTER	5 THE CHASE, GILLINGHAM, KENT, ME8 6AG, U.K

PCT International Classification Number

B21C 23/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	9505380.7	1995-03-17	U.K.