CA1176085A - Forging blank for an internal threaded cylinder - Google Patents
Forging blank for an internal threaded cylinderInfo
- Publication number
- CA1176085A CA1176085A CA000394850A CA394850A CA1176085A CA 1176085 A CA1176085 A CA 1176085A CA 000394850 A CA000394850 A CA 000394850A CA 394850 A CA394850 A CA 394850A CA 1176085 A CA1176085 A CA 1176085A
- Authority
- CA
- Canada
- Prior art keywords
- forging blank
- forging
- blank
- threads
- cylinder
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/56—Making machine elements screw-threaded elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
- B21J5/06—Methods for forging, hammering, or pressing; Special equipment or accessories therefor for performing particular operations
- B21J5/12—Forming profiles on internal or external surfaces
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Forging (AREA)
Abstract
F?RENADE FABRIKSVERKEN
"Forging blank for an internal threaded cylinder"
A b s t r a c t A forging blank for the production of threaded tubes or cylinders by coldforging around an externally threaded mandrel (2), whereby the material in the forging blank is displaced into the mandrel s thread grooves (15).
The forging blank is mostly formed with an outer diameter corresponding to the required profile depth of the threads (20) in the final forged cylinder, while the blank at one or more places is formed with thicker or thinner diameters to form thread profiles with increasing and decreasing thread profiles. One form of the invention concerns a forging blank, which at both ends is conically shaped (17) so that starting cones are formed in the forged product. The blank can also be formed with a centrally thickened portion (16) to form one or more threads with a deeper profile, producing a barrier or a locking for rods which are to be screwed into the sleeve.
(Figure 2 is recommended for publication)
"Forging blank for an internal threaded cylinder"
A b s t r a c t A forging blank for the production of threaded tubes or cylinders by coldforging around an externally threaded mandrel (2), whereby the material in the forging blank is displaced into the mandrel s thread grooves (15).
The forging blank is mostly formed with an outer diameter corresponding to the required profile depth of the threads (20) in the final forged cylinder, while the blank at one or more places is formed with thicker or thinner diameters to form thread profiles with increasing and decreasing thread profiles. One form of the invention concerns a forging blank, which at both ends is conically shaped (17) so that starting cones are formed in the forged product. The blank can also be formed with a centrally thickened portion (16) to form one or more threads with a deeper profile, producing a barrier or a locking for rods which are to be screwed into the sleeve.
(Figure 2 is recommended for publication)
Description
1~-67~
FORENADE FABRIKSVERKEN
Forging blank for an internal threaded cylinder.
The present invention concerns a forging blank for an internal threa-ded cylinder which is to be produced by cold forging around an external threaded mandrel. By cylinder means in this case any kind of tube or part of a tube of steel or other metal suitable for cold forging.
Internal threads in tubes or cylinders have earlier been produced by turning or other cutting methodsi It has also been possible to produce them by cold forging or hammering whereby a tube or cylinder shaped work-piece is cold forged around an external threaded mandrel, which is later removed from the tube or cylinder.
Cold forging involves several advantages compared to cutting methods.
By cold forging, a finer surface finish can be achieved than with cutting methods, the material becomes harder as metal fibers are not cut, internal stresses from earlier handling are eliminated, practically any type of form of thread can be produced to extremely fine tolerances and cold forged products are produced with an even and high quality etc.
In many cases with internal threaded tubes or cylinders, a starting cone to the thread is required, specially where joining sleeves for rods such as drilling rods are concerned, and it is required that the cylinder screws easily to the rod. Earlier methods have been to grind, turn or in , ~ ~ 7~085 other ways produce the threads starting cone. Grinding or turning involves an extra and cost increasing working step and there is also the risk that such methods create burrs or damage to the thread which would make it difficult to screw the rod into the cylinder.
The invention therefore concerns a forging blank or work-piece, which is shaped in such a way that the final forged threaded cylinder is automatically given a starting cone at one end or at both ends.
The invention provides forging blank for the production of internally threaded cylinders by cold forging on an externally threaded mandrel, wherein the forging blank along the major part of its length has an outer diameter which exceeds the required outer diameter of the final forged cylinder by an amount which corresponds to the required profile depth of the cylinders internal threads, and wherein the forging blank at one or more places is formed on the outside with thicker or thinner parts intended to form threads of lncreasing or decreasing profiles in the final forged cylinder, and wherein the forging blank at one or both of its ends is formed with a conically sloping part intended to form a starting cone for the threads of the final forged cylinder. The conically sloping end part causes a reduced material displacement at the end, so that only a small amount of material is pressed into the mandrel grooves. The cylinder is thus automatically given an internal starting cone for the thread.
The invention will now be described in more detail with reference to the accompanying drawings wherein:
Figure 1 shows diagrammatically and in an axial section a g 2 60 ~ 5 simple device or tool for the production of an internally threaded cylinder;
Figure 2 shows in a larger scale a part of the device shown in Figure 1 before cold forging; and Figure 3 shows the final forged cylinder.
The tool shown in Figure 1 mainly comprises a forging tool 1, in which an externally threaded mandrel 2 and a forging blank 3 for a joining sleeve are set up. The forging blank is intended, by the action of cold forging, to be worked into required form by a number of forging hammers 4 of which only one is shown in the drawing.
The forging tool 1 comprises an end socket 5 in which an end positioner 6 with collar is loosely fitted. The surface of the end positioner 6 is 2a arranged to act as a s~op for the end 7 of the mandrel 2 and by varying the axial width of end positioners collar, the mandrel s position in relation to the forging blank 3 can be adjusted. The end socket 5 is arranged so that its one end ~ acts as a holder for the one end of the forging blank 3. The other end of the workpiece is supported by one end 9 of a driver 10, which displaceably also supports the other end 11 of the forging workpiece 2.
The driver also comprises a spring loaded ram 12 whiçh forces the mandrel 2 against the end positioner 6 in the end socket 5. The tool 1 is rotatable and for this purpose the end socket 5 is shaped with a journal 13 which can be supported in a ball bearing and the driver 10 is similarly shaped with a shaft end 14 which can be coupled to a motor to rotate the forging tool together with the mandrel and forging blank.
The forging hammers 4 can be driven by excenters which intermittently press the hammers against the workpiece while the tool is run past the ham-mers. The workpiece is thereby successively worked from one end to the other and is done so by enough force that the material of the forging blank is displaced, whereby the worked material flows into the mandrel s 2 thread grooves 15. The tool is held together by that the end socket 5 is hydrau-lically or pneumatically loaded in an axial direction with a given force, while the driver 10 is actuated in the opposite direction with a substantially larger force, so that the tool is successively driven under the forging hammers.
Simultaneously with the successive forging of the workpiece from one end to the other, the workpiece increases in length in the same direction as the hammers start working the blank, to the right as is shown in figure 1 and the blank must therefore be calculated shorter than the final length.
In many cases it is required that the threads in the final product are of different height and according to the invention the workpiece can be for-med thereafter so that the required form and si~e of the threads are auto-4 1 178o85 matically produced during forging and subsequent machining becomes un-necessary. It may be required that one or two heavy threads are to be formed in the cylinder's axial middle position, to achieve a locking effect for the threaded rod or so that the rod cannot be threaded in more than to the slee-ve's middle point. In the latter case the product may be formed as a thicke-ning or bulge 16, as is indicated by figure 2.
A more usual requirement is however that the threads at the ends have a starting cone to simplify screwing in the threaded rods. This is accomp-lished by making the forging blank conically decreasing in diameter towards its ends 17, whereby forging from the ends creates a successively increa-sing amount of material which is pressed into the mandrel's threads 15, whereby the thread height in the final product successively increases from the cone's beginning 18 to its end point 19, from which point a constant material displacement is maintained. The starting cones 17 can have a vary-ing angle v depending on the required cone angle V required at the start or end of the cylinder's thread 20. The starting point 18 of the blank's cone 17 can lie over, on or even under the required level 21 for the final forged cylinder's outer diameter, but normally the starting point lies a little above the said level 21 so that some thread is formed at the beginning of the cylinder.
In the shown case the threaded mandrel 2 is formed with a central cir-cular groove 22 to form a central rib 23 in the forged cylinder, which is intended as a safety measure so that the threaded rod cannot be screwed in further than the sleeve's axial middle point.
The same effect can be obtained if the mandrel's thread grooves 15 are formed deeper at the sleeve's middle point or if the thread grooves 15 are formed throughout with a greater depth than the required profile depth in the final forged product. In this latter case the threads are forged down to a little play in relation to the base of the thread grooves 15, 1 17608~
at all places except where the workpiece at the middle is formed with a bulge 16, where the blank will be formed down to the base of the profile.
The larger profile depth at the cylinder's central threads act as stop so that the threaded rod cannot be screwed in further than a certain position.
A practical embodiment of the invention is the production of a ioining sleeve for drilling bars by using a forging blank which, according to the invention has a length of approximately 165 mm, an inner diameter of approximately 39 mm and an outer diameter of approximately 62 mm. At both ends the forging blank is formed with ring shaped clamping part 24 for the attachment of forging blank to the end socket 5 and driver 10, and from the clamping ends the forging blank is conical with angle v of about 10 from a diameter of approximately 54 mm. The cone 17, which gives a starting cone in the cylinder, has a length of approximately 21 mm. After forging the product'has an outer diameter of approximately'52 mm and the inside threads formed by forging has a starting cone angle V of approximately 8.
The reader must understand that the description above and embodiments of the invention shown on the drawings are only illustrative examples and that many modifications can be made and exist within the scope of the following claims.
FORENADE FABRIKSVERKEN
Forging blank for an internal threaded cylinder.
The present invention concerns a forging blank for an internal threa-ded cylinder which is to be produced by cold forging around an external threaded mandrel. By cylinder means in this case any kind of tube or part of a tube of steel or other metal suitable for cold forging.
Internal threads in tubes or cylinders have earlier been produced by turning or other cutting methodsi It has also been possible to produce them by cold forging or hammering whereby a tube or cylinder shaped work-piece is cold forged around an external threaded mandrel, which is later removed from the tube or cylinder.
Cold forging involves several advantages compared to cutting methods.
By cold forging, a finer surface finish can be achieved than with cutting methods, the material becomes harder as metal fibers are not cut, internal stresses from earlier handling are eliminated, practically any type of form of thread can be produced to extremely fine tolerances and cold forged products are produced with an even and high quality etc.
In many cases with internal threaded tubes or cylinders, a starting cone to the thread is required, specially where joining sleeves for rods such as drilling rods are concerned, and it is required that the cylinder screws easily to the rod. Earlier methods have been to grind, turn or in , ~ ~ 7~085 other ways produce the threads starting cone. Grinding or turning involves an extra and cost increasing working step and there is also the risk that such methods create burrs or damage to the thread which would make it difficult to screw the rod into the cylinder.
The invention therefore concerns a forging blank or work-piece, which is shaped in such a way that the final forged threaded cylinder is automatically given a starting cone at one end or at both ends.
The invention provides forging blank for the production of internally threaded cylinders by cold forging on an externally threaded mandrel, wherein the forging blank along the major part of its length has an outer diameter which exceeds the required outer diameter of the final forged cylinder by an amount which corresponds to the required profile depth of the cylinders internal threads, and wherein the forging blank at one or more places is formed on the outside with thicker or thinner parts intended to form threads of lncreasing or decreasing profiles in the final forged cylinder, and wherein the forging blank at one or both of its ends is formed with a conically sloping part intended to form a starting cone for the threads of the final forged cylinder. The conically sloping end part causes a reduced material displacement at the end, so that only a small amount of material is pressed into the mandrel grooves. The cylinder is thus automatically given an internal starting cone for the thread.
The invention will now be described in more detail with reference to the accompanying drawings wherein:
Figure 1 shows diagrammatically and in an axial section a g 2 60 ~ 5 simple device or tool for the production of an internally threaded cylinder;
Figure 2 shows in a larger scale a part of the device shown in Figure 1 before cold forging; and Figure 3 shows the final forged cylinder.
The tool shown in Figure 1 mainly comprises a forging tool 1, in which an externally threaded mandrel 2 and a forging blank 3 for a joining sleeve are set up. The forging blank is intended, by the action of cold forging, to be worked into required form by a number of forging hammers 4 of which only one is shown in the drawing.
The forging tool 1 comprises an end socket 5 in which an end positioner 6 with collar is loosely fitted. The surface of the end positioner 6 is 2a arranged to act as a s~op for the end 7 of the mandrel 2 and by varying the axial width of end positioners collar, the mandrel s position in relation to the forging blank 3 can be adjusted. The end socket 5 is arranged so that its one end ~ acts as a holder for the one end of the forging blank 3. The other end of the workpiece is supported by one end 9 of a driver 10, which displaceably also supports the other end 11 of the forging workpiece 2.
The driver also comprises a spring loaded ram 12 whiçh forces the mandrel 2 against the end positioner 6 in the end socket 5. The tool 1 is rotatable and for this purpose the end socket 5 is shaped with a journal 13 which can be supported in a ball bearing and the driver 10 is similarly shaped with a shaft end 14 which can be coupled to a motor to rotate the forging tool together with the mandrel and forging blank.
The forging hammers 4 can be driven by excenters which intermittently press the hammers against the workpiece while the tool is run past the ham-mers. The workpiece is thereby successively worked from one end to the other and is done so by enough force that the material of the forging blank is displaced, whereby the worked material flows into the mandrel s 2 thread grooves 15. The tool is held together by that the end socket 5 is hydrau-lically or pneumatically loaded in an axial direction with a given force, while the driver 10 is actuated in the opposite direction with a substantially larger force, so that the tool is successively driven under the forging hammers.
Simultaneously with the successive forging of the workpiece from one end to the other, the workpiece increases in length in the same direction as the hammers start working the blank, to the right as is shown in figure 1 and the blank must therefore be calculated shorter than the final length.
In many cases it is required that the threads in the final product are of different height and according to the invention the workpiece can be for-med thereafter so that the required form and si~e of the threads are auto-4 1 178o85 matically produced during forging and subsequent machining becomes un-necessary. It may be required that one or two heavy threads are to be formed in the cylinder's axial middle position, to achieve a locking effect for the threaded rod or so that the rod cannot be threaded in more than to the slee-ve's middle point. In the latter case the product may be formed as a thicke-ning or bulge 16, as is indicated by figure 2.
A more usual requirement is however that the threads at the ends have a starting cone to simplify screwing in the threaded rods. This is accomp-lished by making the forging blank conically decreasing in diameter towards its ends 17, whereby forging from the ends creates a successively increa-sing amount of material which is pressed into the mandrel's threads 15, whereby the thread height in the final product successively increases from the cone's beginning 18 to its end point 19, from which point a constant material displacement is maintained. The starting cones 17 can have a vary-ing angle v depending on the required cone angle V required at the start or end of the cylinder's thread 20. The starting point 18 of the blank's cone 17 can lie over, on or even under the required level 21 for the final forged cylinder's outer diameter, but normally the starting point lies a little above the said level 21 so that some thread is formed at the beginning of the cylinder.
In the shown case the threaded mandrel 2 is formed with a central cir-cular groove 22 to form a central rib 23 in the forged cylinder, which is intended as a safety measure so that the threaded rod cannot be screwed in further than the sleeve's axial middle point.
The same effect can be obtained if the mandrel's thread grooves 15 are formed deeper at the sleeve's middle point or if the thread grooves 15 are formed throughout with a greater depth than the required profile depth in the final forged product. In this latter case the threads are forged down to a little play in relation to the base of the thread grooves 15, 1 17608~
at all places except where the workpiece at the middle is formed with a bulge 16, where the blank will be formed down to the base of the profile.
The larger profile depth at the cylinder's central threads act as stop so that the threaded rod cannot be screwed in further than a certain position.
A practical embodiment of the invention is the production of a ioining sleeve for drilling bars by using a forging blank which, according to the invention has a length of approximately 165 mm, an inner diameter of approximately 39 mm and an outer diameter of approximately 62 mm. At both ends the forging blank is formed with ring shaped clamping part 24 for the attachment of forging blank to the end socket 5 and driver 10, and from the clamping ends the forging blank is conical with angle v of about 10 from a diameter of approximately 54 mm. The cone 17, which gives a starting cone in the cylinder, has a length of approximately 21 mm. After forging the product'has an outer diameter of approximately'52 mm and the inside threads formed by forging has a starting cone angle V of approximately 8.
The reader must understand that the description above and embodiments of the invention shown on the drawings are only illustrative examples and that many modifications can be made and exist within the scope of the following claims.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Forging blank for the production of internally threaded cylinders by cold forging on an externally threaded mandrel, wherein the forging blank along the major part of its length has an outer diameter which exceeds the required outer diameter of the final forged cylinder by an amount which corresponds to the required profile depth of the cylinders internal threads, and wherein the forging blank at one or more places is formed on the outside with thicker or thinner parts intended to form threads of increasing or decreasing profiles in the final forged cylinder, and wherein the forging blank at one or both of its ends is formed with a conically sloping part intended to form a starting cone for the threads of the final forged cylinder.
2. Forging blank according to claim 1, wherein the conically sloped part has a diameter corresponding to or a little larger than the required finished outer diameter of the final forged cylinder.
3. Forging blank according to claim 1, wherein at least one region of the blank is formed with an external bulge intended to form threads of a deeper thread profile than the other threads and provide a barrier or locking portion for threaded rods which in use are to be engaged in the final forged cylinder.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8100774A SE435908B (en) | 1981-02-03 | 1981-02-03 | CASTLE SUBJECT FOR MANUFACTURING INTERNAL THROUGH PIPES OR SHELTS |
| SE81/00774-2 | 1981-02-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1176085A true CA1176085A (en) | 1984-10-16 |
Family
ID=20343044
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000394850A Expired CA1176085A (en) | 1981-02-03 | 1982-01-25 | Forging blank for an internal threaded cylinder |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1176085A (en) |
| DE (1) | DE3203233A1 (en) |
| SE (1) | SE435908B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10236281A1 (en) | 2002-08-08 | 2004-02-19 | Ina-Schaeffler Kg | Method for manufacturing spindle nuts for ball thread drives involves arranging externally profiled tool mandrel in hollow blank and exerting radial force from outside to reshape blank to form helical track |
-
1981
- 1981-02-03 SE SE8100774A patent/SE435908B/en unknown
-
1982
- 1982-01-25 CA CA000394850A patent/CA1176085A/en not_active Expired
- 1982-02-01 DE DE19823203233 patent/DE3203233A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| DE3203233A1 (en) | 1982-09-23 |
| SE8100774L (en) | 1982-08-04 |
| SE435908B (en) | 1984-10-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |