CA2256153A1 - Tube end-forming method and apparatus - Google Patents
Tube end-forming method and apparatus Download PDFInfo
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- CA2256153A1 CA2256153A1 CA 2256153 CA2256153A CA2256153A1 CA 2256153 A1 CA2256153 A1 CA 2256153A1 CA 2256153 CA2256153 CA 2256153 CA 2256153 A CA2256153 A CA 2256153A CA 2256153 A1 CA2256153 A1 CA 2256153A1
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- radial
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D41/00—Application of procedures in order to alter the diameter of tube ends
- B21D41/04—Reducing; Closing
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- Exhaust Silencers (AREA)
Abstract
A method of reducing an end portion of a tube having an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, to an essentially circular cross-section, said method comprising feeding said end portion to a forming tool comprising a plurality of adjustable, segmented jaws having a cumulative inner surface defining a cavity having (a) an entry aperture defining an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, said aperture adapted to operably receive said end portion of said tube in surface abutment therewith; (b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis; and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section. The method provides for a unitary exhaust tube of leak-proof construction which provides a consistently tight fit with appended components.
Description
TUBE END-FORMING METHOD AND APPARATUS
S
FIELD OF THE INVENTION
This invention relates to a method and apparatus for performing operations on the end of a part such as a tube, pipe and the like; and, particularly, changing an elliptical, oval or similar non-circular mouth of said part to an essentially circular mouth.
BACKGROUND OF THE INVENTION
Many systems, such as exhaust treatment devices, require formed tube of considerable complexity in shape and size and may, in some circumstances, involve the production of metal tube with varying diameters and cross-sectional shapes.
Over the length of such an exhaust system, the cross-sectional area and shape may change numerous times to satisfy requirements of the system. Exhaust treatment catalytic converters having an oval or elliptical shaped tube are just one type of tube that carries hot exhaust gases to and from the system.
There are many reasons why the cross-sectional diameter and/or shape of a tube is varied. One reason is to utilize space that is not already accounted for but already necessary in the shell of a machine "reduced packing factor". Another reason is a result of a tube path restriction where it is more economical to change the shape of the tube than to re-rout the path of the tube. In a situation where a circular cross-sectional part would be normally preferred but the space available confines its installation in only one direction, say, for example, the vertical axis but not in the horizontal direction perpendicular to the vertical axis, the designer may choose to use an elliptical or oval cross-section tube of similar cross-sectional area.
In the automotive industry, for example, there is an increasing need to manufacture more complex tubular shapes that are more economically viable.
Further, since emission controls on exhaust systems have become more and more limiting, there is a need to produce these systems of a leak-proof construction. However, problems associated with the manufacture of prior art exhaust treatment devices generally result in unwanted leakage of gases from the container of the device itself and premature failure.
Prior art so called "clamshell" converters are made from two stamped halves which form the body of the exhaust treatment device. The substrate and sealing components are fitted between the two halves and the resultant shell then seam welded. Variations in the substrate dimensions resulting from such manufacture often results in the converters "rattling" and leaking. Further, because the treatment device housing is made from stamped pieces, it is difficult to obtain a consistently tight fit between the housing and the substrate. Further, desirable manufacturing processes must eliminate or reduce the creation of defects, such as wrinkles, kinks and the like, on the shells of these tubes.
Current methods that are practiced to fabricate a section which contains an oval cross-section and cylindrical inlet andlor outlet leads usually incorporate the aforesaid joining process, whereby multiple parts are combined by welding, swaging or equivalent treatments to combine multiple parts.
Methods and apparatus are known for reducing an end portion of a tube having a first circular cross-section to a second circular cross-section of smaller diameter by means of feeding the end portion in a forming tool comprising a plurality of adjustable jaws having a cumulative inner surface defining a fructo-conical shape to symmetrically contact the outer surface of the end portion with the inner surface of the forming tool and subjecting the end portion to a symmetrical force to effect circular cross-section diameter reduction.
Method and apparatus are also known whereby an end portion of a tube having a circular cross-section is non-symmetrically expanded to an oval or elliptical cross-section by means of a ram tool comprising one tapered die operably rammed within the end portion of the tube and effecting even expansion of the circular end along one axis only to form the oval part.
However, the use of a mufti jawed tool to change the cross-sectional shape of an end portion of a tube to essentially circular from oval or elliptical, to-date, is novel and provides an advantageous solution to the aforesaid disadvantages of apparatus and methods for making exhaust gas treatment devices.
S
FIELD OF THE INVENTION
This invention relates to a method and apparatus for performing operations on the end of a part such as a tube, pipe and the like; and, particularly, changing an elliptical, oval or similar non-circular mouth of said part to an essentially circular mouth.
BACKGROUND OF THE INVENTION
Many systems, such as exhaust treatment devices, require formed tube of considerable complexity in shape and size and may, in some circumstances, involve the production of metal tube with varying diameters and cross-sectional shapes.
Over the length of such an exhaust system, the cross-sectional area and shape may change numerous times to satisfy requirements of the system. Exhaust treatment catalytic converters having an oval or elliptical shaped tube are just one type of tube that carries hot exhaust gases to and from the system.
There are many reasons why the cross-sectional diameter and/or shape of a tube is varied. One reason is to utilize space that is not already accounted for but already necessary in the shell of a machine "reduced packing factor". Another reason is a result of a tube path restriction where it is more economical to change the shape of the tube than to re-rout the path of the tube. In a situation where a circular cross-sectional part would be normally preferred but the space available confines its installation in only one direction, say, for example, the vertical axis but not in the horizontal direction perpendicular to the vertical axis, the designer may choose to use an elliptical or oval cross-section tube of similar cross-sectional area.
In the automotive industry, for example, there is an increasing need to manufacture more complex tubular shapes that are more economically viable.
Further, since emission controls on exhaust systems have become more and more limiting, there is a need to produce these systems of a leak-proof construction. However, problems associated with the manufacture of prior art exhaust treatment devices generally result in unwanted leakage of gases from the container of the device itself and premature failure.
Prior art so called "clamshell" converters are made from two stamped halves which form the body of the exhaust treatment device. The substrate and sealing components are fitted between the two halves and the resultant shell then seam welded. Variations in the substrate dimensions resulting from such manufacture often results in the converters "rattling" and leaking. Further, because the treatment device housing is made from stamped pieces, it is difficult to obtain a consistently tight fit between the housing and the substrate. Further, desirable manufacturing processes must eliminate or reduce the creation of defects, such as wrinkles, kinks and the like, on the shells of these tubes.
Current methods that are practiced to fabricate a section which contains an oval cross-section and cylindrical inlet andlor outlet leads usually incorporate the aforesaid joining process, whereby multiple parts are combined by welding, swaging or equivalent treatments to combine multiple parts.
Methods and apparatus are known for reducing an end portion of a tube having a first circular cross-section to a second circular cross-section of smaller diameter by means of feeding the end portion in a forming tool comprising a plurality of adjustable jaws having a cumulative inner surface defining a fructo-conical shape to symmetrically contact the outer surface of the end portion with the inner surface of the forming tool and subjecting the end portion to a symmetrical force to effect circular cross-section diameter reduction.
Method and apparatus are also known whereby an end portion of a tube having a circular cross-section is non-symmetrically expanded to an oval or elliptical cross-section by means of a ram tool comprising one tapered die operably rammed within the end portion of the tube and effecting even expansion of the circular end along one axis only to form the oval part.
However, the use of a mufti jawed tool to change the cross-sectional shape of an end portion of a tube to essentially circular from oval or elliptical, to-date, is novel and provides an advantageous solution to the aforesaid disadvantages of apparatus and methods for making exhaust gas treatment devices.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method of changing the shape of an end portion of a tube having an elliptical or like oval cross-section to an essentially circular cross section.
It is a further object to provide apparatus for effecting said change in said end portion.
Accordingly, in one aspect the invention provides a method of reducing an end portion of a tube having an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, to an essentially circular cross-section, said method comprising feeding said end portion to a forming tool comprising a plurality of adjustable, segmented jaws having a cumulative inner surface defining a cavity having (a) an entry aperture defining an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, said aperture adapted to operably receive said end portion of said tube in surface abutment therewith;
(b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis;
and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section The invention is of particular value in producing an oval tube having a round end or two round ends, which is formed from a single oval piece. The resultant oval tube portion provides for reduced space requirements, for example, beneath an automobile, truck and the like, while having inner components, such as a catalytic converter system, between its two round ends. The round ends enable suitable connections to be made to other round conduits and the like.
The present invention relates in one embodiment to a metal tube end forming machine and process, and , particularly, for deforming at least one end of a hollow metal tube or pipe with a generally oval cross-section in such a way that the end is converted to an essentially circular cross-section. The resulting circular cross-section, may, but not necessarily, have a smaller diameter than the originating minor diameter of the y-axis of the oval or elliptical cross-section.
In a further aspect the invention provides apparatus for reducing an end portion of a tube having an oval or elliptical cross-section, said apparatus comprising (i) a forming tool comprising a plurality of adjustable, segmented jaws having a cumulative inner surface defining a cavity having (a) an entry aperture defining an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, said aperture adapted to operably receive said end portion of said tube in surface abutment therewith;
(b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis;
and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section.
(ii) means for feeding an end portion of a tube having an oval or elliptical cross-section to said entry aperture of said cavity;
(iii) means for reducing said end portion through said cavity to effect reduction of said end portion to a circular cross-section; and (iv) means for releasing said end portion from said forming tool.
The present invention provides a new and improved method for fabricating an end of a tube, pipe and the like to a suitable circular shape as a one-piece tube, while retaining the oval cross-sectional shape of the non-end portions of the tube, so as to advantageously reduce the packing factor of the manufactured part and eliminate the need to use welding and like tools to join two semi-shell parts and reduce the cross sectional area and volume of the installed tube. Additionally, the resultant suitably shaped tube made according to the fabricating method of the invention limits the likelihood of the tube leaking fluid, particularly, hot exhaust gas. Further, the costs of manufacturing an equivalent tube by eliminating the need to weld or join multiple parts to form an equivalent internal profile, are reduced.
Surprisingly, we have found that the process of the invention does not cause the tube material to become unsatisfactorily work hardened in consequence of the deforming 5 the oval tube material to the desired extent. Work hardening is a material effect that occurs in metals during forming to cause it to become brittle and result in tearing or breaking during a reshaping operation.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be better understood, a preferred embodiment will now be described by way of example only, with reference to the accompanying drawings wherein Fig. 1 is a diagrammatic perspective view of forming apparatus according to the invention;
Fig. 2 is a perspective view of a forming tool of use within the apparatus of Fig. 1;
Fig. 3 is a perspective view of the forming tool of Figs. 1 and 2, partially broken away by removal of two jaws;
Fig. 4 is a perspective view of an oval automotive exhaust tube prior to forming according to the invention;
Fig. S is end, side and perspective view of the completed interface indicating the oval cross section being reduced to a circular cross section of diameter smaller than both the maj or and minor diameters of the oval tube;
Fig. SA represents a perspective view of a reduced exhaust tube manufactured according to the process of the invention;
Fig. SB is a diagrammatic side view of the tube of Fig. SA;
Fig. SC is a front view of the tube of Fig. SA;
Fig. 6 is a sectional view of one opposing pair of jaws showing internal elements of the tool including the same features which allow the plurality of jaws to retract radially; and wherein the same numerals denote like parts.
It is an object of the present invention to provide a method of changing the shape of an end portion of a tube having an elliptical or like oval cross-section to an essentially circular cross section.
It is a further object to provide apparatus for effecting said change in said end portion.
Accordingly, in one aspect the invention provides a method of reducing an end portion of a tube having an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, to an essentially circular cross-section, said method comprising feeding said end portion to a forming tool comprising a plurality of adjustable, segmented jaws having a cumulative inner surface defining a cavity having (a) an entry aperture defining an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, said aperture adapted to operably receive said end portion of said tube in surface abutment therewith;
(b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis;
and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section The invention is of particular value in producing an oval tube having a round end or two round ends, which is formed from a single oval piece. The resultant oval tube portion provides for reduced space requirements, for example, beneath an automobile, truck and the like, while having inner components, such as a catalytic converter system, between its two round ends. The round ends enable suitable connections to be made to other round conduits and the like.
The present invention relates in one embodiment to a metal tube end forming machine and process, and , particularly, for deforming at least one end of a hollow metal tube or pipe with a generally oval cross-section in such a way that the end is converted to an essentially circular cross-section. The resulting circular cross-section, may, but not necessarily, have a smaller diameter than the originating minor diameter of the y-axis of the oval or elliptical cross-section.
In a further aspect the invention provides apparatus for reducing an end portion of a tube having an oval or elliptical cross-section, said apparatus comprising (i) a forming tool comprising a plurality of adjustable, segmented jaws having a cumulative inner surface defining a cavity having (a) an entry aperture defining an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, said aperture adapted to operably receive said end portion of said tube in surface abutment therewith;
(b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis;
and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section.
(ii) means for feeding an end portion of a tube having an oval or elliptical cross-section to said entry aperture of said cavity;
(iii) means for reducing said end portion through said cavity to effect reduction of said end portion to a circular cross-section; and (iv) means for releasing said end portion from said forming tool.
The present invention provides a new and improved method for fabricating an end of a tube, pipe and the like to a suitable circular shape as a one-piece tube, while retaining the oval cross-sectional shape of the non-end portions of the tube, so as to advantageously reduce the packing factor of the manufactured part and eliminate the need to use welding and like tools to join two semi-shell parts and reduce the cross sectional area and volume of the installed tube. Additionally, the resultant suitably shaped tube made according to the fabricating method of the invention limits the likelihood of the tube leaking fluid, particularly, hot exhaust gas. Further, the costs of manufacturing an equivalent tube by eliminating the need to weld or join multiple parts to form an equivalent internal profile, are reduced.
Surprisingly, we have found that the process of the invention does not cause the tube material to become unsatisfactorily work hardened in consequence of the deforming 5 the oval tube material to the desired extent. Work hardening is a material effect that occurs in metals during forming to cause it to become brittle and result in tearing or breaking during a reshaping operation.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be better understood, a preferred embodiment will now be described by way of example only, with reference to the accompanying drawings wherein Fig. 1 is a diagrammatic perspective view of forming apparatus according to the invention;
Fig. 2 is a perspective view of a forming tool of use within the apparatus of Fig. 1;
Fig. 3 is a perspective view of the forming tool of Figs. 1 and 2, partially broken away by removal of two jaws;
Fig. 4 is a perspective view of an oval automotive exhaust tube prior to forming according to the invention;
Fig. S is end, side and perspective view of the completed interface indicating the oval cross section being reduced to a circular cross section of diameter smaller than both the maj or and minor diameters of the oval tube;
Fig. SA represents a perspective view of a reduced exhaust tube manufactured according to the process of the invention;
Fig. SB is a diagrammatic side view of the tube of Fig. SA;
Fig. SC is a front view of the tube of Fig. SA;
Fig. 6 is a sectional view of one opposing pair of jaws showing internal elements of the tool including the same features which allow the plurality of jaws to retract radially; and wherein the same numerals denote like parts.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
With reference to Fig. 1, this shows, generally as 10, a Model HP90 machine head 12, commercially available from Eagle-Eaton Leonard, Brantford, Ontario, Canada, S having a front plate 14 in a forward position to enable a forming tool shown generally as 16 to be seen on head 12. Front plate 14 has an axial aperture 18 defined by a fructo-conical inner surface 19 of plate 14.
Tool 16 has a barrel assembly 20 and a plurality of adjustable, segmented jaws which cumulatively defines a fructo-conical outer surface 22 complimentary to and operably received by inner surface 14, when plate 14 is operably moved axially forward of too116 on a pair of shafts 24, by mechanical means (not shown). Jaws 21 cumulatively have an inner surface 26 which defines an inner cavity 28 which operatively receives an automative exhaust gas tube 30 shown in ghost lines and in Fig. 4.
With reference to Fig. 2, cumulative inner surface 26 defines cavity 28 having (i) an entry aperture portion 32 having an oval or elliptical cross-section with a radial major or x-axis xl longer than its radial minor or y-axis, y', perpendicular thereto;
(ii) an essentially circular cross-section inner portion 34 operably of the same radial length as the narrow or y-axis of tube 30; and (iii) an intermediate portion 36 between aperture 32 and inner portion 34 defining an inner surface 38 of reducing cross-section along radial x-axis such that the length of xl tends to that of y'.
With reference to Fig. 6, barrel assembly 20 has a plurality of compression springs 40, equivalent in number to jaws 21, being 8 in the embodiment shown.
Jaws 21 are suitably arranged to expand and contract subject to the radial limits imposed by barrel assembly 20 and a retention band 42. Springs 40 are sandwiched between adjacent jaws 21 and provide the means to encourage jaws 21 to expand and maintain a gap 44 between adjacent jaws 21. Band 42 is wrapped around an outer surface portion of jaws 21 and provides alignment to jaws 21 when the jaws expand. In alternative embodiments, other numbers of jaws and jaw arrangements may be used. Preferably, a minimum of four, most practically 4 - 16, and most preferably, 8 - 16 jaws.
With reference to Fig. 1, this shows, generally as 10, a Model HP90 machine head 12, commercially available from Eagle-Eaton Leonard, Brantford, Ontario, Canada, S having a front plate 14 in a forward position to enable a forming tool shown generally as 16 to be seen on head 12. Front plate 14 has an axial aperture 18 defined by a fructo-conical inner surface 19 of plate 14.
Tool 16 has a barrel assembly 20 and a plurality of adjustable, segmented jaws which cumulatively defines a fructo-conical outer surface 22 complimentary to and operably received by inner surface 14, when plate 14 is operably moved axially forward of too116 on a pair of shafts 24, by mechanical means (not shown). Jaws 21 cumulatively have an inner surface 26 which defines an inner cavity 28 which operatively receives an automative exhaust gas tube 30 shown in ghost lines and in Fig. 4.
With reference to Fig. 2, cumulative inner surface 26 defines cavity 28 having (i) an entry aperture portion 32 having an oval or elliptical cross-section with a radial major or x-axis xl longer than its radial minor or y-axis, y', perpendicular thereto;
(ii) an essentially circular cross-section inner portion 34 operably of the same radial length as the narrow or y-axis of tube 30; and (iii) an intermediate portion 36 between aperture 32 and inner portion 34 defining an inner surface 38 of reducing cross-section along radial x-axis such that the length of xl tends to that of y'.
With reference to Fig. 6, barrel assembly 20 has a plurality of compression springs 40, equivalent in number to jaws 21, being 8 in the embodiment shown.
Jaws 21 are suitably arranged to expand and contract subject to the radial limits imposed by barrel assembly 20 and a retention band 42. Springs 40 are sandwiched between adjacent jaws 21 and provide the means to encourage jaws 21 to expand and maintain a gap 44 between adjacent jaws 21. Band 42 is wrapped around an outer surface portion of jaws 21 and provides alignment to jaws 21 when the jaws expand. In alternative embodiments, other numbers of jaws and jaw arrangements may be used. Preferably, a minimum of four, most practically 4 - 16, and most preferably, 8 - 16 jaws.
Segmented jaws 21 collectively provide the vehicle to radially deform segments axial of the length of the portion of the oval tube to provide a gradually reduced, deformed end tube portion. Major x-axis jaws 46 deforms oval tube 30 major or x-axis diameter to a greater extent than minor diameter jaws 48 deforms tube 30 minor diameter segment the least.
Fig. SA is end, side and perspective view of the completed interface indicating the oval cross section being reduced to a circular cross section of diameter smaller than both the major and minor diameters of the oval tube.
Thus, the plurality of jaws 21 can be divided into two main working elements, i.e.
an internal geometry and an external geometry, which provides the means to radially contract the plurality of jaws 21.
External cone surface 22 of the plurality of jaws 21 is axially symmetrical of the jaws and is designed to mate within aperture 19 and provides the means to radially contract the plurality of jaws 21 and, thus, the oval tube in the inner cavity 28.
Segmented-reshaping-tool 16 may be considered to comprise a hollow geometry that matches the transition area 50 of completed oval tube product 52 - Figs.
SA - SC.
The shape and diameters of the leading cross-sectional surface 54, at the open end i.e.
aperture 32 of segmented-reshaping-tool 16 in its closed position is designed to match the shape and diameters oval tube 30 prior to end forming. The shape and diameter of the finishing cross-section surface 56, at the internal end tool 16, in its closed position is designed to match the transition area 50 of tube 30 and have a final opening of circular cross-section 58. The transition cross-sectional-surface 36 is the surface on tool 16 between leading cross-sectional-surface 32 and finishing cross-sectional-surface 34, in the closed position, and is designed to "blend" the leading and finishing cross-sectional-surfaces 32, 34 of tool 16 and match the profile and contours of the completed oval tube 52.
In operation, oval tube 30 is aligned with tool 16 and secured by means of an oval tube clamp 60 in a position such that the centers of both oval tube 30 and 16 are concentric. Clamp 60 eliminates the movement of tube 30in all directions.
Clamp 60 has means (not shown) to move a clamped tube 30 in a series of steps towards tool 16. The clamp's means is independent of front plate 14.
Fig. SA is end, side and perspective view of the completed interface indicating the oval cross section being reduced to a circular cross section of diameter smaller than both the major and minor diameters of the oval tube.
Thus, the plurality of jaws 21 can be divided into two main working elements, i.e.
an internal geometry and an external geometry, which provides the means to radially contract the plurality of jaws 21.
External cone surface 22 of the plurality of jaws 21 is axially symmetrical of the jaws and is designed to mate within aperture 19 and provides the means to radially contract the plurality of jaws 21 and, thus, the oval tube in the inner cavity 28.
Segmented-reshaping-tool 16 may be considered to comprise a hollow geometry that matches the transition area 50 of completed oval tube product 52 - Figs.
SA - SC.
The shape and diameters of the leading cross-sectional surface 54, at the open end i.e.
aperture 32 of segmented-reshaping-tool 16 in its closed position is designed to match the shape and diameters oval tube 30 prior to end forming. The shape and diameter of the finishing cross-section surface 56, at the internal end tool 16, in its closed position is designed to match the transition area 50 of tube 30 and have a final opening of circular cross-section 58. The transition cross-sectional-surface 36 is the surface on tool 16 between leading cross-sectional-surface 32 and finishing cross-sectional-surface 34, in the closed position, and is designed to "blend" the leading and finishing cross-sectional-surfaces 32, 34 of tool 16 and match the profile and contours of the completed oval tube 52.
In operation, oval tube 30 is aligned with tool 16 and secured by means of an oval tube clamp 60 in a position such that the centers of both oval tube 30 and 16 are concentric. Clamp 60 eliminates the movement of tube 30in all directions.
Clamp 60 has means (not shown) to move a clamped tube 30 in a series of steps towards tool 16. The clamp's means is independent of front plate 14.
Segmented forming tool 16 is contracted by means of moving front plate 14 towards and over external cone surface 22. Whereby inner surface 19 of plate 14 applies an outward radial force against external cone surface 22 to effect a contraction of segmented jaws 21 which in turn apply inward radial forces against opposing surfaces of tube 30. In their closed position, the plurality of jaws 21 has no gaps 44 in its diameter.
As front plate 14 and inner surface 19 retract from the plurality of jaws 21, tool 14 becomes free to expand under influence of compression springs 20.
In more detail, the operation of reducing an oval-sectional tube 30 a circular cross-section is as follows.
Oval tube clamp 60 is fed into tool 16 so as to align the leading cross-sectional-surface 32 and leading surface of oval tube 30. The opened tool 16 is then closed by moving front plate 14 towards tool 16 wherein surface 19 exerts a radial force over surface 22 to cause radial contraction of segmented-reshaping-tool 16 and pressing leading cross-sectional-surface 32 onto aligned surface of oval tube 30 to effect deformation of it in such a manner as to match the complimentary profile of cross-sectional surface deformation of 32. Closed tool 16 is then opened by means moving front plate 14 axially from tool 16, which, in turn, effects expansion of segmented-reshaping-tool jaws 21 and release of partially formed oval tube.
Tube clamp 60 is then advanced further into segmented-reshaping-tool 16 so as to expose the next portion of tube 30 to tool 16. This cycling process is repeated continuously by means of a cooperative movement among oval tube clamp 60 feeding mechanism and the opening and closing of jaws 21 until the desired oval interface reaction has been completed. The number of cycles necessary to complete a finished interface is dependent on oval tube's 30 geometry, composition and processing history, and the shape of the transition cross-sectional surface. In one embodiment, one end of an oval tube manufactured by the welding of a 3.5 mm thick 409 stainless steel sheet and having a major diameter i.e. xl of approximately 100 mm and a minor diameter i.e. yl of 60 mm can be reduced to a circular diameter of 50 mm according to the present invention by use of a segmented-reshaping-tool 16 having an axial length of approximately 75 mm, a straight taper between the leading and finishing transition cross-sectional surface 32, 34 in a series of steps, wherein plate 14 and tool 16 are cycled and tube clamp 60 is advanced, relatively one to the other approximating 5 - 15 mm at a machine cycle rate of approximately 6 cycles per second.
After the full forming process is completed, oval tube clamp 60 is retracted to its unload position in one continuous motion and end-formed tube 30 removed from clamp 60.
Clearly, there are practical geometrical limitations to the shape of the cumulative inner surface of jaws 21 The inner surface angle between an axial segment within jaws 21 and its axial axis cannot exceed some maximum angle. Beyond this maximum angle, the force necessary to feed the tube end portion into jaws 21 becomes too large and causes the tube wall to collapse in the tube axial direction. Additionally, the ratio of oval tube's 30 major diameter to minor diameter must be considered in that if this ratio exceeds a certain value oval tube 30 wall at its minor diameter will collapse.
These geometrical limitations can be readily determined by the person skilled in the art from a consideration of tube material, thickness and the unlisted and final end formed shapes.
Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalents of the specific embodiments and features that have been described and illustrated.
As front plate 14 and inner surface 19 retract from the plurality of jaws 21, tool 14 becomes free to expand under influence of compression springs 20.
In more detail, the operation of reducing an oval-sectional tube 30 a circular cross-section is as follows.
Oval tube clamp 60 is fed into tool 16 so as to align the leading cross-sectional-surface 32 and leading surface of oval tube 30. The opened tool 16 is then closed by moving front plate 14 towards tool 16 wherein surface 19 exerts a radial force over surface 22 to cause radial contraction of segmented-reshaping-tool 16 and pressing leading cross-sectional-surface 32 onto aligned surface of oval tube 30 to effect deformation of it in such a manner as to match the complimentary profile of cross-sectional surface deformation of 32. Closed tool 16 is then opened by means moving front plate 14 axially from tool 16, which, in turn, effects expansion of segmented-reshaping-tool jaws 21 and release of partially formed oval tube.
Tube clamp 60 is then advanced further into segmented-reshaping-tool 16 so as to expose the next portion of tube 30 to tool 16. This cycling process is repeated continuously by means of a cooperative movement among oval tube clamp 60 feeding mechanism and the opening and closing of jaws 21 until the desired oval interface reaction has been completed. The number of cycles necessary to complete a finished interface is dependent on oval tube's 30 geometry, composition and processing history, and the shape of the transition cross-sectional surface. In one embodiment, one end of an oval tube manufactured by the welding of a 3.5 mm thick 409 stainless steel sheet and having a major diameter i.e. xl of approximately 100 mm and a minor diameter i.e. yl of 60 mm can be reduced to a circular diameter of 50 mm according to the present invention by use of a segmented-reshaping-tool 16 having an axial length of approximately 75 mm, a straight taper between the leading and finishing transition cross-sectional surface 32, 34 in a series of steps, wherein plate 14 and tool 16 are cycled and tube clamp 60 is advanced, relatively one to the other approximating 5 - 15 mm at a machine cycle rate of approximately 6 cycles per second.
After the full forming process is completed, oval tube clamp 60 is retracted to its unload position in one continuous motion and end-formed tube 30 removed from clamp 60.
Clearly, there are practical geometrical limitations to the shape of the cumulative inner surface of jaws 21 The inner surface angle between an axial segment within jaws 21 and its axial axis cannot exceed some maximum angle. Beyond this maximum angle, the force necessary to feed the tube end portion into jaws 21 becomes too large and causes the tube wall to collapse in the tube axial direction. Additionally, the ratio of oval tube's 30 major diameter to minor diameter must be considered in that if this ratio exceeds a certain value oval tube 30 wall at its minor diameter will collapse.
These geometrical limitations can be readily determined by the person skilled in the art from a consideration of tube material, thickness and the unlisted and final end formed shapes.
Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalents of the specific embodiments and features that have been described and illustrated.
Claims (9)
1. A method of reducing an end portion of a tube having an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, to an essentially circular cross-section, said method comprising feeding said end portion to a forming tool comprising a plurality of adjustable, segmented jaws having a cumulative inner surface defining a cavity having (a) an entry aperture defining an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, said aperture adapted to operably receive said end portion of said tube in surface abutment therewith;
(b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis;
and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section.
(b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis;
and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section.
2. A method as defined in claim 1 comprising feeding said end portion to said entry aperture and reducing said end portion through said cavity to said inner portion through said intermediate portion, and withdrawing said end portion from said cavity of said forming tool.
3. A method as defined in claims 1 or 2 wherein said tube constitutes a metallic housing of an exhaust treatment device.
4. A method as defined in claims 1 or 2 wherein said tool further comprises adjustment means to operably effect adjustment of said jaws to vary said radial x- and y-axes of said cavity.
5. A method as defined in claim 1 wherein said essentially circular cross-section at said inner portion of said cavity is operably of the same radial length as said radial y-axis of said tube.
6. Apparatus for reducing an end portion of a tube having an oval or elliptical cross-section, said apparatus comprising (i) a forming tool comprising a plurality of adjustable, segmented jaws having a cumulative inner surface defining a cavity having (a) an entry aperture defining an oval or elliptical cross-section with a radial x-axis longer than its radial y-axis perpendicular thereto, said aperture adapted to operably receive said end portion of said tube in surface abutment therewith;
(b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis;
and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section.
(ii) means for feeding an end portion of a tube having an oval or elliptical cross-section to said entry aperture of said cavity;
(iii) means for reducing said end portion through said cavity to effect reduction of said end portion to a circular cross-section; and (iv) means for releasing said end portion from said forming tool.
(b) an essentially circular cross-section operably of the same radial length as said radial y-axis of said tube inner portion of said cavity; and (c) an intermediate portion between said aperture and said inner portion defining a surface of reducing cross-section along said radial x-axis;
and subjecting said end portion within said cavity to a sufficient force to effect reduction of said radial x-axis relative to said radial y-axis to produce said end portion having said essentially circular cross-section.
(ii) means for feeding an end portion of a tube having an oval or elliptical cross-section to said entry aperture of said cavity;
(iii) means for reducing said end portion through said cavity to effect reduction of said end portion to a circular cross-section; and (iv) means for releasing said end portion from said forming tool.
7. Apparatus as defined in claim 6 further comprising adjustment means to effect adjustment of said jaws to vary said radial x- and y-axes of said cavity.
8. Apparatus as defined in claim 6 or claim 7 wherein said forming tool has at least six jaws.
9. Apparatus as defined in claim 7 having 8 - 16 jaws.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2256153 CA2256153A1 (en) | 1998-12-15 | 1998-12-15 | Tube end-forming method and apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2256153 CA2256153A1 (en) | 1998-12-15 | 1998-12-15 | Tube end-forming method and apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2256153A1 true CA2256153A1 (en) | 2000-06-15 |
Family
ID=29425818
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2256153 Abandoned CA2256153A1 (en) | 1998-12-15 | 1998-12-15 | Tube end-forming method and apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2256153A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103861963A (en) * | 2014-03-15 | 2014-06-18 | 山东梦金园珠宝首饰有限公司 | Automatic thin wall gold tube necking machine |
| WO2016082839A1 (en) * | 2014-11-28 | 2016-06-02 | Værktøjsfabrikken Paw V/Helene Nedergaard | Method for final forming of an open end of a pipe in one set-up and an apparatus con-figured to carry out the method |
| WO2018119753A1 (en) * | 2016-12-28 | 2018-07-05 | 深圳市配天机器人技术有限公司 | Multi-station pipe necking device |
| CN114151179A (en) * | 2021-11-03 | 2022-03-08 | 东风商用车有限公司 | Diameter reduction precision improving method of post-treatment catalytic unit, diameter reduction system and main control device |
-
1998
- 1998-12-15 CA CA 2256153 patent/CA2256153A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103861963A (en) * | 2014-03-15 | 2014-06-18 | 山东梦金园珠宝首饰有限公司 | Automatic thin wall gold tube necking machine |
| WO2016082839A1 (en) * | 2014-11-28 | 2016-06-02 | Værktøjsfabrikken Paw V/Helene Nedergaard | Method for final forming of an open end of a pipe in one set-up and an apparatus con-figured to carry out the method |
| WO2018119753A1 (en) * | 2016-12-28 | 2018-07-05 | 深圳市配天机器人技术有限公司 | Multi-station pipe necking device |
| CN109562433A (en) * | 2016-12-28 | 2019-04-02 | 深圳市综科食品智能装备有限公司 | A kind of multistation tubing necking equipment |
| CN114151179A (en) * | 2021-11-03 | 2022-03-08 | 东风商用车有限公司 | Diameter reduction precision improving method of post-treatment catalytic unit, diameter reduction system and main control device |
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