CA1306453C - Method for severing the ends of tubing - Google Patents
Method for severing the ends of tubingInfo
- Publication number
- CA1306453C CA1306453C CA000574014A CA574014A CA1306453C CA 1306453 C CA1306453 C CA 1306453C CA 000574014 A CA000574014 A CA 000574014A CA 574014 A CA574014 A CA 574014A CA 1306453 C CA1306453 C CA 1306453C
- Authority
- CA
- Canada
- Prior art keywords
- tube
- shear blade
- die
- shear
- shearing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Metal Extraction Processes (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Method for severing the ends of tubing by feeding the end of a tube through a die such that its end to be sheared extends beyond the die while presenting a shear blade with a pointed end in the interior of the tube end. After the shear blade is inserted into the tube, relative vertical movement between the shear blade and the tube is effected to cause the pointed end to initially puncture the tube wall adjacent the die. The shearing blade is thereafter shifted laterally and vertically to shear remaining portions of the tube wall.
Method for severing the ends of tubing by feeding the end of a tube through a die such that its end to be sheared extends beyond the die while presenting a shear blade with a pointed end in the interior of the tube end. After the shear blade is inserted into the tube, relative vertical movement between the shear blade and the tube is effected to cause the pointed end to initially puncture the tube wall adjacent the die. The shearing blade is thereafter shifted laterally and vertically to shear remaining portions of the tube wall.
Description
0~ c i M~T~OD FOR S~VERING TH~ ENDS QF TUBING
BACKGROyND OF ~ Y~IQ~
~hile not limited thereto, the pre~ent invention ha~ partlcular utility in combination with apparatus or forming internal threads on the ends of j.
tubing. After the end of the tube has been expanded, a threadad mandrel i~ lnserted th2rein and a die is thereafter forced over the end of the tube. In this process, which is essentially a aold extruslon proce~, the die, as it i8 forced over the end of the tube, cau~es its inner periphery to conform to the ~?
tread~ on the mandrel. This i~ ~ollowed by rotation ~.
and removal of the mandrel fr~m the tube end, leavîng the cold-~ormed internal threads intact.
In thi~ process, and as the die i6 foraed 'f over the mandrel, the resulting extrusion effcct elongates the tube and forms a varia~le lenqth flashin~ on its end. Thi3 fla~hing must be removed subsequently in the shearing process without deforming the tube end itself.
While tha invention is useful in a threading operation as described above, it will be understood .
that it al80 has application to any manufacturing operation where it is necessary to ~hear off the end o~ a tube without deforming the same.
~3~
,, ,` :
SUMMAl~tY OF THE INVENTION
In accordance with the presPnt invention, a new and improved method is provided for shearing an end ~rom tubing without deforming the same, the method being particularly adapted for use with a cold~orming threading operation a~ described above. Specifically, a method ~or severing the ende of tubing comprising ~eeding the end of a tube through a die such that the end of the tube to be sheared extends beyond the die, ;:
pre~e~ting a shear blade with a pointed end in the interior of the end of a tube, causing relative vertical movement between the shear blade and the tube to cause the pointed end to initially puncture and extend exteriorly of the tube wall adjacent the die, and therea~ter ~hifting the shear blade from the puncture site about a tube wall shearing path generally transverse to the length of the tube by laterally moving ths sh~ar blade ~rom the puncture site and then vertioally moving the ~hear blade to shear a remaining portion o~ the tube wall.
In the pre~erred embodiment of the X~
invention, the shear blade is arcuate in configuration ~i except at said pointed end, and the shear blade i5 ~`.
initially moved vertically to cause the pointed end to puncture the tube wall, the shear blade being thereafter shifted laterally and downwardly to ~.
complete severing o~ a 180 degree segment of the tube. ~-.
~, ~3~ 3 t Following these step~, the shear blade is moved upwardly anfl displaced about the othsr 180 degxee segment whereby lts arcuate surface will aomplete shearing of the tu~e along the remainin~ 180 degree ~:
segment of the tube.
In another embodiment of the invention, the ~hear blade i~ generally diamond shaped and initially ~.
moves upwardly to ~orce a ~irst pointed end through approxlmately a 90 degree arc on the periphery of tha ~, tube. ~hereaftar, it is moved downwardly whereby a second pointed end shears a diametrically opposite 90 degree arcuate portion of the tube. The shear blade is then ~oved upwardly and laterally in both directions to sh~ar the remaining 90 degree arcuate portions of the tube.
The above and other objects and features O~ k;
the invention will become apparent from the following ''', detailed description taken in connection with the accompanying drawings which form a part of this specifi¢ation and in which:
Figures 7 A, lB and lC schematically ~' illustrate the manner in which internal threads can be ~;
cold-formed on the end of a tube, the process being bj', shown in ~igures lA, lB and lC being particularly .,.
adapted for use with the present invention; "' r .
3 ~:
,.
.. . . . . . . . . . ..... . . . O. ... ~ . .
.
Figure 2 i/s a schematic side view of typical apparatus for shearinq tube ends in accordance with the teaching of the invention:
Figures 3A-3G are end view~ showing the manner in which tube ends are ~heared in accordance with one em~odiment of the present invention;
Figure ~ illustrates a hydraulic cylinder arrangement for actuating the shearing blade to accomplish the shearing operation shown in Figures 3A- t 3G; and Figure 5A-5F schematically illustrate another embodiment of the invention wherein a shearing blade of di~erent con~iguration i~ utilized than that shown in Figures 3A~3G.
With reference now to the drawings, and particularly to Figures lA, lB and lC there iB shown a i.
method, generally known ~n the art, for gorming internal threads on the interior o~ tubing wherein a threaded mandrel la is inserted into the end of a tubular workpiece 12 along the dir~ction of arrow 14 once the end o~ the tube has been expanded. A~ter the : mandrel 10 is inserted into the end o~ workpiece 12, a die 16 i~ forced over the end of the tubular workpiece l' 12 along the direction of arrow 18. Since the diameter of the die 16 is less than that of the expanded end o~ the tubular workpiece 12, but greater than that o~ the mandrel 10, the expanded end o~ the 4 ~~i p:
, ~3~6~
:
tube is ~orced inwa~dly and onto the mandrel 10, whereby the end of the tu~e is reduced in diameter as shown in Figure lC. At the same time, its inner periphery i5 forced onto the threads of the mandrel 10, thereby forming internal threads on the workpiece 12 as sown in Figure lC. Thereafter, the mandrel is unthreaded from the end 22 of the workpiece 12, while leaving internal threads therein. This process is ~.
particularly adapted for use in forming tubular shell~ ,:
for automotive shock absorbed; however, it also has "
other applications.
A~ the die 16 is forced over the end of the tubular workpiece 12 to reduce the diameter of its expanded end and form internal threads thereon, the tube end extrudes oukwardly and to the left a~ shown in Figure lC, thereby formin~ a flashing 24 of : variable length which must bs subsequently removed.
In Figure 2, one embodiment of the shearing apparatus o~ the present invention i8 shown.
Initially, the workpiece 26, shown without ~nternal thread~, is ~orced through a die 28 such that the ~., ~lashing or end to be removed projects beyond the end !:
~ace 32 of the die 28. Workpiece 26 is clamped in place by means of separable clamp jaws 34; and the 5hearin~ blade 36 is inserted into the tubular workpiece such that its forward end is slightly behind the forward end ~ace 32 of the die 28.
~.3~ j3 With re~er~nce to Figures 3A-3G, it can be seen that in t~e part~ular embodiment of the invention shown, the shear 36 is provided with 1-incllned ~hearing surPaces 40 which extend downwardly at angles of about 45 degrees ~xom an upper point 38.
The lower portion of the blade 36 is identified by the re~erence numeral 42 and is generally semicircular in :
conPiguration. The shearing operation starts by moving the blade 36 upwardly as viewad in Figures 3A-3B. In this process, the point 38 puncture~ the tube wall, cutting away ears 44 and 46 which pro~ect outwardly and away from the tube. Following upward movement of the blade, it is then shifted laterally to the left as shown in Figure 3C and i5 then moved downwardly as show in Figure 3D. In this process, less than one hal~ oP the tube is shear~d by the lower semicircular shearing edge 42. Following the step shown in Figure 3D, the shearing blade 36 is moved upwardly as shown in Figure 3E and then to the right a~ shown in Figure 3F. The ~inal step of the process ,.
is a downward movement o~ the shearing blade 36 to shear the remaining portion of the tube as shown in Figure 3G~ Following the steps shown in Figure 3G, the shearing blade 36 is then moved into the position shown in Figure 3A. t ' Typical apparatus for moving the shearing ~.
blade 36 is shown in Figure ~. The shearing blade is . 6 k .. .. . .. . .. . ......
carried on a crosshead 50 mounted for vertical reciprocal movement on sha~ts 5~ and 54 and ~or trans~erse or lataral movement on gha~ts 56 and 58.
Engagable with the crosshead 50 are two vertical hydraulic cylinders 60 and 62 and two horizontal cylinders 64 and 66. The cylinders 60-66, in turn, are connected through suitable hydraulic circuitry to hydraulic logic circuitry 78 to effect the movements .
schematically illustrated in Figures 3A-3G.
Another embodiment of the invention in shown in Figures 5A-5F, it being understood that the tube is f again inserted into a die such as die 28 shown in Figure 2 and clamped by jaws 34. In this case, the shearing blade 6~ is diamond shaped in configuration and has upper and lower pointed ends 70 and 72 as well p:
as diamQtrically opposite side pointed ends 74 and 76. ~i In this embodiment of the invention, the shearing blade i8 i~itially inserted into the tube as before ,t~
and is thereafter moved upwardly as shown in Figure 5B
to shear ~he upper portion o~ the tu~e, in much the same way as in the previous embodim~nt. Thereafter, k the shearing blade 68 i8 moved downwardly to shear the bottom of the tube as shown in Figure 5C and is then ~.
moved upwardly and back in to coaxial alignment with !''~' the tube 26 to be sheared. Fo~lowing this procedure, the shearing blade 68 is moved to the left as viewed in Figure 5E to completely shear one half of the tube J
, , ~3~S~
., and is thereafter mo~ed to the right as shown in Figure 5F to shear the other hal~ of the tube. The ;;
operation is completed, of coursa, by returning the shearing blade 68 to the position shown in Figure 5Ao Althou~h the invention has been shown in conjunction with certain specific embodiments, it will be readily apparent to those skilled in th~ art that various changes in form and arrangement of parts may be made to suit requirements w.ithout d~parting ~rom the spirit and scope of the invention.
~';
~
~, ~.
~.
~l~
.. , . .. .. ~ . .
. .
BACKGROyND OF ~ Y~IQ~
~hile not limited thereto, the pre~ent invention ha~ partlcular utility in combination with apparatus or forming internal threads on the ends of j.
tubing. After the end of the tube has been expanded, a threadad mandrel i~ lnserted th2rein and a die is thereafter forced over the end of the tube. In this process, which is essentially a aold extruslon proce~, the die, as it i8 forced over the end of the tube, cau~es its inner periphery to conform to the ~?
tread~ on the mandrel. This i~ ~ollowed by rotation ~.
and removal of the mandrel fr~m the tube end, leavîng the cold-~ormed internal threads intact.
In thi~ process, and as the die i6 foraed 'f over the mandrel, the resulting extrusion effcct elongates the tube and forms a varia~le lenqth flashin~ on its end. Thi3 fla~hing must be removed subsequently in the shearing process without deforming the tube end itself.
While tha invention is useful in a threading operation as described above, it will be understood .
that it al80 has application to any manufacturing operation where it is necessary to ~hear off the end o~ a tube without deforming the same.
~3~
,, ,` :
SUMMAl~tY OF THE INVENTION
In accordance with the presPnt invention, a new and improved method is provided for shearing an end ~rom tubing without deforming the same, the method being particularly adapted for use with a cold~orming threading operation a~ described above. Specifically, a method ~or severing the ende of tubing comprising ~eeding the end of a tube through a die such that the end of the tube to be sheared extends beyond the die, ;:
pre~e~ting a shear blade with a pointed end in the interior of the end of a tube, causing relative vertical movement between the shear blade and the tube to cause the pointed end to initially puncture and extend exteriorly of the tube wall adjacent the die, and therea~ter ~hifting the shear blade from the puncture site about a tube wall shearing path generally transverse to the length of the tube by laterally moving ths sh~ar blade ~rom the puncture site and then vertioally moving the ~hear blade to shear a remaining portion o~ the tube wall.
In the pre~erred embodiment of the X~
invention, the shear blade is arcuate in configuration ~i except at said pointed end, and the shear blade i5 ~`.
initially moved vertically to cause the pointed end to puncture the tube wall, the shear blade being thereafter shifted laterally and downwardly to ~.
complete severing o~ a 180 degree segment of the tube. ~-.
~, ~3~ 3 t Following these step~, the shear blade is moved upwardly anfl displaced about the othsr 180 degxee segment whereby lts arcuate surface will aomplete shearing of the tu~e along the remainin~ 180 degree ~:
segment of the tube.
In another embodiment of the invention, the ~hear blade i~ generally diamond shaped and initially ~.
moves upwardly to ~orce a ~irst pointed end through approxlmately a 90 degree arc on the periphery of tha ~, tube. ~hereaftar, it is moved downwardly whereby a second pointed end shears a diametrically opposite 90 degree arcuate portion of the tube. The shear blade is then ~oved upwardly and laterally in both directions to sh~ar the remaining 90 degree arcuate portions of the tube.
The above and other objects and features O~ k;
the invention will become apparent from the following ''', detailed description taken in connection with the accompanying drawings which form a part of this specifi¢ation and in which:
Figures 7 A, lB and lC schematically ~' illustrate the manner in which internal threads can be ~;
cold-formed on the end of a tube, the process being bj', shown in ~igures lA, lB and lC being particularly .,.
adapted for use with the present invention; "' r .
3 ~:
,.
.. . . . . . . . . . ..... . . . O. ... ~ . .
.
Figure 2 i/s a schematic side view of typical apparatus for shearinq tube ends in accordance with the teaching of the invention:
Figures 3A-3G are end view~ showing the manner in which tube ends are ~heared in accordance with one em~odiment of the present invention;
Figure ~ illustrates a hydraulic cylinder arrangement for actuating the shearing blade to accomplish the shearing operation shown in Figures 3A- t 3G; and Figure 5A-5F schematically illustrate another embodiment of the invention wherein a shearing blade of di~erent con~iguration i~ utilized than that shown in Figures 3A~3G.
With reference now to the drawings, and particularly to Figures lA, lB and lC there iB shown a i.
method, generally known ~n the art, for gorming internal threads on the interior o~ tubing wherein a threaded mandrel la is inserted into the end of a tubular workpiece 12 along the dir~ction of arrow 14 once the end o~ the tube has been expanded. A~ter the : mandrel 10 is inserted into the end o~ workpiece 12, a die 16 i~ forced over the end of the tubular workpiece l' 12 along the direction of arrow 18. Since the diameter of the die 16 is less than that of the expanded end o~ the tubular workpiece 12, but greater than that o~ the mandrel 10, the expanded end o~ the 4 ~~i p:
, ~3~6~
:
tube is ~orced inwa~dly and onto the mandrel 10, whereby the end of the tu~e is reduced in diameter as shown in Figure lC. At the same time, its inner periphery i5 forced onto the threads of the mandrel 10, thereby forming internal threads on the workpiece 12 as sown in Figure lC. Thereafter, the mandrel is unthreaded from the end 22 of the workpiece 12, while leaving internal threads therein. This process is ~.
particularly adapted for use in forming tubular shell~ ,:
for automotive shock absorbed; however, it also has "
other applications.
A~ the die 16 is forced over the end of the tubular workpiece 12 to reduce the diameter of its expanded end and form internal threads thereon, the tube end extrudes oukwardly and to the left a~ shown in Figure lC, thereby formin~ a flashing 24 of : variable length which must bs subsequently removed.
In Figure 2, one embodiment of the shearing apparatus o~ the present invention i8 shown.
Initially, the workpiece 26, shown without ~nternal thread~, is ~orced through a die 28 such that the ~., ~lashing or end to be removed projects beyond the end !:
~ace 32 of the die 28. Workpiece 26 is clamped in place by means of separable clamp jaws 34; and the 5hearin~ blade 36 is inserted into the tubular workpiece such that its forward end is slightly behind the forward end ~ace 32 of the die 28.
~.3~ j3 With re~er~nce to Figures 3A-3G, it can be seen that in t~e part~ular embodiment of the invention shown, the shear 36 is provided with 1-incllned ~hearing surPaces 40 which extend downwardly at angles of about 45 degrees ~xom an upper point 38.
The lower portion of the blade 36 is identified by the re~erence numeral 42 and is generally semicircular in :
conPiguration. The shearing operation starts by moving the blade 36 upwardly as viewad in Figures 3A-3B. In this process, the point 38 puncture~ the tube wall, cutting away ears 44 and 46 which pro~ect outwardly and away from the tube. Following upward movement of the blade, it is then shifted laterally to the left as shown in Figure 3C and i5 then moved downwardly as show in Figure 3D. In this process, less than one hal~ oP the tube is shear~d by the lower semicircular shearing edge 42. Following the step shown in Figure 3D, the shearing blade 36 is moved upwardly as shown in Figure 3E and then to the right a~ shown in Figure 3F. The ~inal step of the process ,.
is a downward movement o~ the shearing blade 36 to shear the remaining portion of the tube as shown in Figure 3G~ Following the steps shown in Figure 3G, the shearing blade 36 is then moved into the position shown in Figure 3A. t ' Typical apparatus for moving the shearing ~.
blade 36 is shown in Figure ~. The shearing blade is . 6 k .. .. . .. . .. . ......
carried on a crosshead 50 mounted for vertical reciprocal movement on sha~ts 5~ and 54 and ~or trans~erse or lataral movement on gha~ts 56 and 58.
Engagable with the crosshead 50 are two vertical hydraulic cylinders 60 and 62 and two horizontal cylinders 64 and 66. The cylinders 60-66, in turn, are connected through suitable hydraulic circuitry to hydraulic logic circuitry 78 to effect the movements .
schematically illustrated in Figures 3A-3G.
Another embodiment of the invention in shown in Figures 5A-5F, it being understood that the tube is f again inserted into a die such as die 28 shown in Figure 2 and clamped by jaws 34. In this case, the shearing blade 6~ is diamond shaped in configuration and has upper and lower pointed ends 70 and 72 as well p:
as diamQtrically opposite side pointed ends 74 and 76. ~i In this embodiment of the invention, the shearing blade i8 i~itially inserted into the tube as before ,t~
and is thereafter moved upwardly as shown in Figure 5B
to shear ~he upper portion o~ the tu~e, in much the same way as in the previous embodim~nt. Thereafter, k the shearing blade 68 i8 moved downwardly to shear the bottom of the tube as shown in Figure 5C and is then ~.
moved upwardly and back in to coaxial alignment with !''~' the tube 26 to be sheared. Fo~lowing this procedure, the shearing blade 68 is moved to the left as viewed in Figure 5E to completely shear one half of the tube J
, , ~3~S~
., and is thereafter mo~ed to the right as shown in Figure 5F to shear the other hal~ of the tube. The ;;
operation is completed, of coursa, by returning the shearing blade 68 to the position shown in Figure 5Ao Althou~h the invention has been shown in conjunction with certain specific embodiments, it will be readily apparent to those skilled in th~ art that various changes in form and arrangement of parts may be made to suit requirements w.ithout d~parting ~rom the spirit and scope of the invention.
~';
~
~, ~.
~.
~l~
.. , . .. .. ~ . .
. .
Claims (8)
1. A method for severing the ends of tubing comprising feeding the end of a tube through a die such that the end of the tube to be sheared extends beyond the die, presenting a shear blade with a pointed end in the interior of said end of a tube, causing relative vertical movement between said shear blade and said tube to cause said pointed end to initially puncture and extend exteriorly of the tube wall adjacent said die, and thereafter shifting said shear blade from the puncture site about a tube wall shearing path generally transverse to the length of the tube by laterally moving the shear blade from the puncture site and then vertically moving the shear blade to shear a remaining portion of the tube wall.
2. The method of claim 1 wherein said shear blade is arcuate in configuration except at said pointed end.
3. The method of claim 2 wherein said shear blade is initially moved vertically to cause said pointed end to puncture the tube wall, the shear blade being thereafter shifted laterally and downwardly to complete severing of a 180 degree segment of the tube, and the shear blade thereafter being moved upwardly and displaced about the other 180 degree segment to complete shearing of the tube along said arcuate surface.
4. A method for severing the ends of tubing comprising feeding the end of a tube through a die such that its end to be sheared extends beyond the die, presenting a shear blade with a pointed end in the interior of said tube end, moving said shear blade vertically to cause said pointed end to initially puncture the tube wall adjacent said die, thereafter shearing additional portions of the tube wall by shifting said shear blade laterally from the puncture site and then downwardly to shear a portion of the tube wall starting from the puncture produced by said pointed end, moving said shear blade vertically upwardly to a position where its pointed end extends through the puncture previously produced in the tube wall, and thereafter moving said shear blade laterally and downwardly in a direction opposite to said initial lateral movement to shear the remaining portion of the tube wall.
5. The method of claim 4 wherein said shear blade has a pointed upper end and a lower arcuate shearing surface.
6. The method of claim 5 including the step of clamping said tubing after it is fed through said die.
7. The method of claim 4 including the step of initially expanding the end of the tube thereby creating an expanded end, inserting a threaded mandrel into said expanded end of the tube, forcing a die over the expanded end to cold extrude the same while forming internal threads on the tube end, removing said mandrel, and thereafter effecting said method of shearing to remove any flashing at a desired length beyond the threads thus formed.
8. The method of claim 4 including the step of initially expanding the end of the tube thereby creating an expanded end, inserting a mandrel into said expanded end of the tube, forcing a die over the expanded end to cold extrude the same while forming a thinner wall on the tube end, removing said mandrel, and thereafter effecting said method of shearing to remove any extruded length extending beyond a desired finished length of the tube end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000574014A CA1306453C (en) | 1988-08-05 | 1988-08-05 | Method for severing the ends of tubing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000574014A CA1306453C (en) | 1988-08-05 | 1988-08-05 | Method for severing the ends of tubing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1306453C true CA1306453C (en) | 1992-08-18 |
Family
ID=4138500
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000574014A Expired - Lifetime CA1306453C (en) | 1988-08-05 | 1988-08-05 | Method for severing the ends of tubing |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1306453C (en) |
-
1988
- 1988-08-05 CA CA000574014A patent/CA1306453C/en not_active Expired - Lifetime
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5445001A (en) | Method and apparatus for forming and cutting tubing | |
| US20070068215A1 (en) | Hollow stepped shaft and method of forming the same | |
| EP2541000A1 (en) | Method for producing metallic-sodium-filled engine valve | |
| CN1137734C (en) | Catheter beveling and die cut process | |
| JP2001514133A (en) | Container manufacturing method and container having pressure compensation opening | |
| CA2226053A1 (en) | Catheter tip mold and cut process | |
| EP0295919B1 (en) | Cold drawing technique and apparatus for forming internally grooved tubes | |
| CA1306453C (en) | Method for severing the ends of tubing | |
| US5396786A (en) | Machine and method for manufacturing crossover fittings | |
| US5533376A (en) | Method for preparing a tubular blank having a thick wall for a following cascade drawing operation | |
| US4799412A (en) | Method for severing the ends of tubing | |
| US2027285A (en) | Method of forming seamless tube couplings | |
| CN1149107C (en) | One-step bevel-forming process using flashing | |
| US3399559A (en) | Method and apparatus for processing tubing | |
| CA1092763A (en) | Method of producing seamless tubular articles having an arcuate portion along the tubular axis | |
| US7140226B2 (en) | Methods for making a bicycle frame part having a disproportionally enlarged end section | |
| JP2004330246A (en) | Method for manufacturing fuel inlet | |
| CN1108917C (en) | Manufacturing apparatus of composite pipe and manufacturing method thereof | |
| CN110814121A (en) | Small-bending-radius push bending method of small-diameter pipe and small-diameter pipe | |
| GB2067944A (en) | Extrusion process | |
| US3856906A (en) | Method for forming threads on plastic nipples | |
| DE69907711D1 (en) | DEVICE AND METHOD FOR PRODUCING A TUBE WITH ENLARGED WALL THICKNESSES AT ITS END | |
| JP2003211522A (en) | Method for manufacturing double-wall corrugated pipe | |
| JP2851561B2 (en) | Metal pipe bending method and apparatus | |
| JPS63224835A (en) | Necking method for tubular product |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |