CN218798848U - Forming device of multi-step part and multi-step part - Google Patents

Abstract

The utility model provides a forming device and many steps part of many steps part, many steps part is at least including the flange portion that connects in order, first pole portion, second pole portion and tail-bar portion, and first pole portion, the pole footpath of second pole portion and tail-bar portion reduces in proper order, forming device includes cold heading machine and feeding mechanism, add between the forming die of cold heading machine and the side cut mould and trade double-layered mould, the circular flange of predetermineeing of first clamping jaw centre gripping is transferred it to trading behind the double-layered mould, its first pole portion of second clamping jaw centre gripping or second pole portion again, then transfer it to the side cut mould again and carry out the flange side cut, with forming flange portion, again through necessary tooth of rubbing with the hands, heat treatment, process such as electroplating can obtain finished product many steps part. The utility model discloses a forming device of many steps part trades double-layered mould through addding, and the conversion is got the position to the clamp of predetermineeing the piece, stabilizes the overmould to it, realizes disposable cold-heading side cut, guarantees product quality, improves production efficiency.

Description

Forming device of multi-step part and multi-step part

Technical Field

The utility model belongs to fastener shaping field especially relates to a forming device and many steps part of many steps part.

Background

The screw is a very common fastener, is a tool for fastening the parts of the device step by utilizing the physics and mathematical principle of the inclined plane circular rotation and the friction of the object, and is an indispensable industrial necessity in daily life: extremely small screws used in cameras, glasses, clocks, electronics, and the like; general screws used for televisions, electric appliances, musical instruments, furniture; large screws and nuts are used for engineering, buildings and bridges; transportation equipment, airplanes, electric trains, automobiles and the like are combined by large and small screws, so that the screws have important tasks in industry, and the yield and the quality of the screws are important.

In the screw, there is a classification for the step screw, and simple understanding is exactly the nonstandard screw that contains two above steps, no matter how many steps, but long and short again, and the screw of long step is easily got the overmould in cold-heading production, but to the screw of some short steps, because the step is many, in the cold-heading in-process, its effective length that can get is very short, especially the overmould of shaping station to side cut station, when utilizing the clamping jaw centre gripping of overmould to transfer material spare, its clamp is tight and open time is all very difficult for adjusting. The production speed must be reduced greatly, otherwise, the conditions of product falling, tail rod part material cutting, trimming and material tilting, cutting and passing through a die clamp, machine collision and the like are easy to occur in the production. As shown in fig. 1, after a multi-step part is preformed, overmoulding trimming is required, the formed preset part at least comprises a preset circular flange 11', a first rod part 12, a second rod part 13 and a tail rod part 14, the thickness of the original clamping jaw 7 can only be designed to be very thin due to the influence of the axial length and the radial width of each step rod, after the preset part is completely demoulded from a master die, the effective clamping length of the original clamping jaw 7 on the second rod part 13 is only 2.0mm, and due to the extremely short effective clamping length, material falling is very easy to occur due to unstable overmoulding clamping in production, the situation of material skewing during trimming is realized, and the production speed can only reach about 50 parts per minute. In order to ensure the quality of edge cutting, the flange edge cutting operation is generally performed by using a head trimming machine after cold heading forming, but the production efficiency is undoubtedly reduced by replacing the machine.

SUMMERY OF THE UTILITY MODEL

In view of the problem that exists among the above-mentioned prior art, the utility model discloses a main aim at provides a forming device and many steps part of many steps part, many steps part is at least including the flange part that connects in order, first pole portion, second pole portion and tail-bar portion, and first pole portion, the pole footpath of second pole portion and tail-bar portion reduces in proper order, forming device adds between the forming die of original cold heading machine and side cut mould and trades and presss from both sides the mould, the conversion is to the clamping position who predetermines the piece, the effective clamp that increases the clamping jaw gets length, stabilize the cross mould and predetermine the piece, guarantee side cut excellent rate, need not whole head machine participation side cut work, practice thrift and exchange machine time, and the production efficiency is improved.

The purpose of the utility model can be realized through the following technical scheme:

the utility model provides a forming device of multi-step part, the multi-step part includes flange portion, first pole portion, second pole portion and the tail-stock portion that connects in order at least, just the rod footpath of first pole portion, second pole portion and tail-stock portion reduces in proper order, forming device of multi-step part is including being equipped with a plurality of forming die and trading clamp mould, the cold heading machine of side cut mould to and be used for carrying out the feeding mechanism of pay-off between a plurality of moulds, feeding mechanism includes first pay-off subassembly and second pay-off subassembly;

the multiple forming dies are matched together to form a preset blank into a preset circular flange, a first rod part, a second rod part and a tail rod part, so that a preset part is obtained;

the clamp changing die is used for changing a feeding clamp for clamping the preset part, so that the first feeding component clamped on the preset circular flange is changed into a second feeding component clamped on the first rod part or the second rod part;

the edge cutting die is used for performing flange edge cutting on the preset piece after the feeding clamp is replaced, so that the preset circular flange is formed into the flange part;

the first feeding assembly at least comprises two first clamping jaws which are oppositely arranged, each first clamping jaw comprises a first clamping part attached to the side face of the corresponding preset circular flange, and a second clamping part attached to the end face, away from the first rod part, of the corresponding preset circular flange; a first clamping space matched with the preset circular flange is formed between the opposite first clamping parts, and the opposite second clamping parts jointly form a stop table matched with the end face; the second pay-off subassembly includes the second clamping jaw of two relative settings at least, the second clamping jaw include with the third clamp part that the side of second pole portion was laminated mutually, it is relative form between the third clamp part with the space is got to the second clamp of first pole portion or second pole portion looks adaptation.

As a further description of the above technical solution, the forming mold, the clip changing mold and the trimming mold each include a main mold and a trimming mold that are correspondingly disposed;

the main die comprises a main die shell, a main die cushion block, a main die ejector pin and a main die core, wherein the main die cushion block, the main die ejector pin and the main die core are arranged in the main die shell;

the die comprises a die stamping shell, a die stamping cushion block and a die stamping thimble which are arranged in the die stamping shell, one end of the die stamping thimble is connected with the die stamping cushion block, and the other end of the die stamping thimble penetrates out of the die stamping shell to be opposite to the main die cavity.

As a further description of the above technical solution, the main mold cavity of the clip changing mold is a straight section cavity, and the inner diameter of the straight section cavity is matched with the rod diameter of the second rod part, or,

the inner diameter of the straight section cavity is matched with the rod diameter of the tail rod part.

As a further description of the above technical solution, a die sleeve is further disposed in the die cushion block of the clip changing die and the trimming die, and one end of the die ejector pin is connected to a die spring in the die sleeve.

As a further description of the above technical solution, when the preset piece is ejected from the forming mold adjacent to the clip changing mold, the first clipping space is opposite to the main mold cavity of the forming mold.

As a further description of the above technical solution, the stopping table has an avoiding portion, and the avoiding portion is formed by inward recessing of the second clamping portion.

As a further description of the above technical solution, the first clamping portion and the third clamping portion are both arc-shaped surfaces, and when in a clamping state, the arc-shaped surfaces are in surface contact with the side surfaces of the preset member.

As a further description of the above technical solution, the cutting device further includes a cutting mechanism, and the cutting mechanism is used for cutting the wire into the preset blank.

The utility model also provides a multiple step part, a serial communication port, including flange portion, first pole portion, the second pole portion that connects in order, just the pole footpath of first pole portion, second pole portion and tail rod portion reduces in proper order, second pole portion is formed with the screw thread.

As a further description of the above technical solution, a head rod portion is further connected to an end of the flange portion away from the first rod portion.

To sum up, the utility model discloses an outstanding effect does:

the utility model discloses a forming device of many steps part adds one between the forming die of original cold heading machine and side cut mould and trades a clamp mould to will be earlier by the former clamping jaw of cross mould between forming die to side cut mould and change the combination of first clamping jaw and second clamping jaw into, carry out once to the clamp of presetting piece press from both sides the conversion of getting the position, thereby greatly increased right the effective centre gripping length of presetting piece, the clamping stability of two clamping jaws all is higher than former clamping jaw, thereby has guaranteed that the presetting piece is by the cross mould stability of forming die to side cut mould, need not to consider the cross mould to fall the material, and the cross mould back side cut is not askew material, does not cut the material, thereby has guaranteed the product goodness rate when having improved cross mould speed, also need not whole head machine to participate in the flange side cut operation, has practiced thrift and has traded the time, has also improved production efficiency greatly.

Drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of a prior art multi-step part being ejected from a forming mold;

fig. 2 is a schematic diagram of the multi-step part formed by the forming mold according to the embodiment of the present invention;

fig. 3 is a schematic view of the multi-step part in the embodiment of the present invention in a state where the clip changing mold is clamped by the second clamping jaw;

fig. 4 is a schematic structural diagram of the multi-step part after cold heading and trimming in the embodiment of the present invention;

fig. 5 is a top view of a multi-step part after cold heading and trimming according to an embodiment of the present invention;

fig. 6 is a schematic view of a multi-step part in a clip changing mold according to another embodiment of the present invention;

the reference numbers illustrate:

11. a flange portion; 12. a first rod portion; 13. a second rod portion; 14. a tail rod part; 15. a head-rod part;

11', presetting a circular flange;

2. forming a mold;

3. changing a clamping mould;

4. a first jaw; 41. a first clamping part; 42. a second clamping part; 43. an avoidance part;

5. a second jaw; 51. a third clamping part;

6. performing primary molding; 61. a main mold core;

7. and (5) original clamping jaws.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "middle", "lower", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or component to which the reference is made must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The following description will be made with reference to fig. 1 to 6 and the embodiments.

The embodiment provides a forming device of a multi-step part, the multi-step part at least comprises a flange part 11, a first rod part 12, a second rod part 13 and a tail rod part 14 which are connected in sequence, the rod diameters of the first rod part 12, the second rod part 13 and the tail rod part 14 are reduced in sequence, the forming device of the multi-step part comprises a cold header provided with a plurality of forming dies 2, a clamping changing die 3 and a trimming die (not shown in the figure), and a feeding mechanism used for feeding materials among the dies, and the feeding mechanism comprises a first feeding component and a second feeding component;

the multiple forming dies 2 are matched together to form a preset blank into a preset circular flange 11', a first rod part 12, a second rod part 13 and a tail rod part 14, so that a preset part is obtained;

the clamp changing die 3 is used for changing a feeding clamp for clamping the preset part, so that the first feeding component clamped on the preset circular flange 11' is changed into a second feeding component clamped on the first rod part 12 or the second rod part 13;

the trimming die is used for performing flange trimming on the preset piece after the feeding clamp is replaced, so that the preset circular flange 11' is formed into the flange part 11;

the first feeding assembly at least comprises two first clamping jaws 4 which are oppositely arranged, and each first clamping jaw 4 comprises a first clamping part 41 attached to the side face of the corresponding preset circular flange 11 'and a second clamping part 42 attached to the end face, away from the first rod part 12, of the corresponding preset circular flange 11'; a first clamping space matched with the preset circular flange 11' is formed between the opposite first clamping parts 41, and the opposite second clamping parts 42 together form a stop table matched with the end surface; the second feeding assembly at least comprises two second clamping jaws 5 which are oppositely arranged, each second clamping jaw 5 comprises a third clamping part 51 which is attached to the side face of the corresponding second rod part 13, and a second clamping space matched with the corresponding first rod part 12 or the corresponding second rod part 13 is formed between the corresponding third clamping parts 51.

Borrow by above-mentioned structure, use multistation cold heading machine processing, carry out the multimode to predetermineeing the blank and dash many, carry out the cold-heading side cut in last mould, production speed can reach 90 per minute, and the operation personnel can utilize earlier to be located trade a plurality of forming die 2 before pressing from both sides the mould 3, will cut off the blank shaping of predetermineeing that forms by the wire rod and do predetermineeing the piece, predetermineeing the piece including predetermineeing circular flange 11', and connect gradually in predetermineeing first pole portion 12, second pole portion 13 and the tailpiece portion 14 under the circular flange 11', the feeding mechanism of a plurality of forming die 2 pieces can use conventional feeding mechanism, and work as predetermineeing after the shaping, utilize first feeding component to transfer it extremely on trading clamp mould 3, reuse second feeding component to transfer it extremely the side cut mould carries out the flange side cut operation, thereby makes predetermineeing circular flange shaping and being flange portion 11. And finally, finishing cold heading, and performing necessary processes of thread rolling, heat treatment, electroplating and the like on the product obtained by cold heading to obtain the finished product multi-step part.

In the cold heading process, the clamp replacing mold 3 is added in front of the trimming mold, the clamping jaws in the original first feeding assembly are replaced by the first clamping jaws 4, the first clamping parts 41 included in the clamp replacing mold are attached to the side faces of the preset circular flange 11', first clamping spaces matched with the preset circular flange 11' are formed between the first clamping parts 41 opposite to each other to clamp and transfer the preset part, meanwhile, the second clamping parts 42 included in the clamp replacing mold can be attached to the end faces, deviating from the first rod part 12, of the preset circular flange 11', the second clamping parts 42 opposite to each other jointly form stop tables matched with the end faces and can also effectively stop the stop tables, the first clamping jaws 4 are prevented from flying out when passing through the preset part at a high speed, the clamping is more stable, and the problem that the product falls due to the time difference between mold stripping and clamping is avoided, so that the product is prevented from falling, the first clamping jaw 4 can smoothly overmould the preset part onto the clamp changing die 3 to wait for clamping and transferring of the second feeding assembly, the second clamping jaw 5 in the second feeding assembly comprises a third clamping part 51 attached to the side surface of the second rod part 13, a second clamping space matched with the first rod part 12 or the second rod part 13 is formed between the opposite third clamping parts 51 to clamp and transfer the preset part, and because the station die does not process the preset part, the thickness of the third clamping part 51 along the axial direction of the preset part is thicker than that of the original clamping jaw 7 without considering the factors when the preset part is ejected from the main die of the station die, so that the effective clamping length of the preset part is prolonged, the preset part can be stably clamped by the second clamping jaw 5 to the trimming die after clamp changing, and trimming operation is smoothly performed on the flange of the preset part, the centre gripping is stable high, has reduced risks such as the crooked material of side cut, the tail rod part 14 cuts the material, has improved product goodness.

From this, add a trade clamp mould 3 between forming die 2 and the trimming die of original cold heading machine to change former clamping jaw 7 of overmoulding between forming die 2 and the trimming die before into the combination of first clamping jaw 4 and second clamping jaw 5, carry out once right the clamp of presetting the piece gets the conversion of position, thereby greatly increased right the effective centre gripping length of presetting the piece, the clamping stability of two clamping jaws all is higher than former clamping jaw 7, thereby has guaranteed the piece is overmoulded by forming die 2 to the overmoulding stability of trimming die, need not to consider the overmoulding and falls the material, and the trimming is not askew material, does not cut the material behind the overmoulding, thereby has guaranteed product goodness when having improved the overmoulding speed, also need not whole head machine participation flange side cut operation, has practiced thrift and has traded the machine time, has also improved production efficiency greatly.

Referring to fig. 2, fig. 3 and fig. 6, in the present embodiment, the forming mold 2, the clip changing mold 3 and the trimming mold (not shown in the drawings) each include a main mold and a punch (not shown in the drawings) that are correspondingly disposed;

the main die comprises a main die shell, a main die cushion block, a main die ejector pin and a main die core 61, wherein the main die cushion block, the main die ejector pin and the main die core 61 are arranged in the main die shell, the main die core 61 is provided with a main die cavity with an opening facing the stamping die, and the main die ejector pin penetrates through the main die cushion block;

the die comprises a die stamping shell, a die stamping cushion block and a die stamping ejector pin which are arranged in the die stamping shell, one end of the die stamping ejector pin is connected with the die stamping cushion block, and the other end of the die stamping ejector pin penetrates out of the die stamping shell to be opposite to the main die cavity.

Referring to fig. 2 and fig. 3, in this embodiment, in the forming mold 2 adjacent to the clip changing mold 3, the middle section of the preset blank formed with the preset circular flange 11' and the tail rod portion 14 is formed into the first rod portion 12 and the second rod portion 13, so as to obtain the preset piece, and the preset piece is ejected out of the main mold cavity by the main mold ejector pin in the main mold. After the punch die in the forming die 2 retreats relative to the main die, the first clamping jaw 4 can move to the die opening position of the main die, so that the first clamping space formed by the first clamping part 41 opposite to the first clamping part is opposite to the main die cavity of the forming die 2 to receive material, and the second clamping part 42 has a limiting effect on the end surface of the preset circular flange 11' departing from the first rod part 12 after receiving the material, so that the preset piece is prevented from flying out.

Specifically, in this embodiment, first clamp 41 and third clamp 51 are the arcwall face, when pressing from both sides the state, it with predetermine the circular flange 11', the pole portion of predetermineeing the piece and all correspond and form the face contact, and the design of arcwall face makes first clamping jaw 4 encircle in the outside of predetermineeing the piece plays the fixed action, thereby has guaranteed right predetermineeing the stable centre gripping of piece. It will be appreciated that, with the main and punch dies arranged horizontally, the first jaw 4, the second jaw 5 and the other transfer jaws arranged between the adjacent dies are all arranged to extend horizontally. In the clamping process, the clamping device can encircle the preset part from the peripheral side, and the first clamping part 41 and the third clamping part 51 are arc-shaped surfaces, so that the bottom of the preset part is supported, and the two sides of the preset part are limited.

Specifically, in this embodiment, the stopping table has an avoiding portion 43, and the avoiding portion 43 is formed by inward recessing of the second clamping portion 42 opposite to the avoiding portion, so that the die ejector pin can penetrate through and abut against the preset member.

Specifically, in this embodiment, a die sleeve is further disposed in the die cushion blocks of the clip changing die 3 and the trimming die, one end of the die ejector pin is connected to the die spring in the die sleeve, and when the preset part transferred by the first clamping jaw 4 and the second clamping jaw 5 is received, the corresponding die ejector pin and the main die ejector pin respectively abut against the preset circular flange 11' and the tail rod portion 14 to deviate from the end surface of the second rod portion 13, and meanwhile, due to the existence of the die spring, the two ejector pins can stably maintain the abutting effect on the preset part, so that the first clamping jaw 4 and the second clamping jaw 5 can be smoothly opened to discharge, the situation of collision with the die cannot occur, and the second clamping jaw 5 cannot be cut by the trimming die.

Referring to fig. 3, in this embodiment, a main mold cavity of the clip changing mold 3 is a straight section cavity, and is adapted to the rod diameter of the tail rod portion 14, so that the portions of the preset piece except the tail rod portion 14 are located outside the main mold and do not need to be sunk into the mold, the second clamping jaw 5 may be thickened to 9.0mm, and the effective clamping length of the preset piece is improved from 2.0mm to 5.7mm, thereby ensuring that the second clamping jaw 5 can stably clamp the second rod portion 13 of the preset piece and overmould the second rod portion to the trimming mold for flange trimming. Of course, in other embodiments, the preset part may have other shapes, such as more formed rod parts or rod parts, and the set clamping position of the second clamping jaw 5 on the preset part may also be other rod parts according to actual production conditions, so as to satisfy stable clamping on the preset part after clamp replacement. For example, in another embodiment, although the rod portion of the preset member only includes the first rod portion 12, the second rod portion 13 and the tail rod portion 14 as shown in fig. 6, the rod diameter of the second rod portion 13 is much smaller than that of the preset circular flange 11' and the first rod portion 12, and the second jaw 5 can be set to be clamped on the first rod portion 12 of the preset member in consideration of the relationship between the opening and closing time of the second jaw 5 and the movement time difference of the die, in this case, the inner diameter of the straight cavity section is correspondingly adapted to the rod diameter of the second rod portion 13, so that the part of the preset member except for the second rod portion 13 and the tail rod portion 14 is located outside the main die.

Specifically, in this embodiment, the forming device further includes a shearing mechanism (not shown in the drawings) located in front of the forming die 2, and configured to shear the wire into the preset blank, and then the preset blank is formed into the preset piece through the plurality of forming dies 2.

Referring to fig. 4 and 5, specifically, in the present embodiment, the provided multi-step component includes a flange portion 11, a first rod portion 12, and a second rod portion 13, which are connected in sequence, rod diameters of the first rod portion 12, the second rod portion 13, and a tail rod portion 14 are sequentially reduced, a thread (not shown in the drawings) is formed on an outer wall of the second rod portion 13 by using a thread rolling process, the flange portion 11 is hexagonal, and in other embodiments, the flange portion 11 may be cut into other shapes according to actual needs.

Referring to fig. 6, in a further embodiment, a head rod portion 15 is further connected to an end of the flange portion 11 of the multi-step part, which is away from the first rod portion 12, and a rod diameter of the head rod portion 15 is smaller than a diameter of the flange portion 11.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing embodiments, or some features may be substituted by other modifications, equivalents, improvements, and the like without departing from the spirit and scope of the invention.

Claims (10)

1. A forming device of a multi-step part at least comprises a flange part, a first rod part, a second rod part and a tail rod part which are connected in sequence, wherein the rod diameters of the first rod part, the second rod part and the tail rod part are reduced in sequence;

the multiple forming dies are matched together and used for forming a preset blank into a preset circular flange, a first rod part, a second rod part and a tail rod part to obtain a preset part;

the clamp changing die is used for changing a feeding clamp for clamping the preset part, so that the first feeding component clamped on the preset circular flange is changed into a second feeding component clamped on the first rod part or the second rod part;

the edge cutting die is used for performing flange edge cutting on the preset piece after the feeding clamp is replaced, so that the preset circular flange is formed into the flange part;

the first feeding assembly at least comprises two first clamping jaws which are oppositely arranged, each first clamping jaw comprises a first clamping part attached to the side face of the corresponding preset circular flange, and a second clamping part attached to the end face, away from the first rod part, of the corresponding preset circular flange; a first clamping space matched with the preset circular flange is formed between the opposite first clamping parts, and the opposite second clamping parts together form a stop table matched with the end face;

the second feeding assembly at least comprises two second clamping jaws which are oppositely arranged, each second clamping jaw comprises a third clamping part which is attached to the side face of the corresponding second rod part, and a second clamping space matched with the first rod part or the second rod part is formed between the corresponding third clamping parts.

2. The apparatus for molding a multi-step part according to claim 1, wherein the molding die, the clip changing die, and the trimming die each include a main die and a punch die which are disposed in correspondence with each other;

the main die comprises a main die shell, a main die cushion block, a main die ejector pin and a main die core, wherein the main die cushion block, the main die ejector pin and the main die core are arranged in the main die shell;

the die comprises a die stamping shell, a die stamping cushion block and a die stamping thimble which are arranged in the die stamping shell, one end of the die stamping thimble is connected with the die stamping cushion block, and the other end of the die stamping thimble penetrates out of the die stamping shell to be opposite to the main die cavity.

3. The apparatus for molding a multi-step part according to claim 2, wherein the main cavity of the clip changing mold is a straight cavity having an inner diameter matched with the diameter of the second rod part, or,

the inner diameter of the straight section cavity is matched with the rod diameter of the tail rod part.

4. The apparatus for forming a multi-step part as claimed in claim 2, wherein a die sleeve is further provided in the die cushion block of the clip changing die and the trimming die, and one end of the die ejector pin is connected to a die spring in the die sleeve.

5. The apparatus for molding a multi-step part according to claim 1, wherein the first clamping space is opposed to a main cavity of the molding die when the preset member is ejected from the molding die adjacent to the clip changing die.

6. The apparatus for forming a multi-step part as claimed in claim 1, wherein said stopper table has a relief portion formed by inwardly recessing said second opposed nip portion.

7. The apparatus of claim 1, wherein the first and third jaws are curved surfaces that are in surface contact with the sides of the predetermined member when in the clamping position.

8. The apparatus for forming a multi-step part as claimed in claim 1, further comprising a shearing mechanism for shearing the wire into the predetermined billet.

9. The multi-step part is characterized by comprising a flange part, a first rod part and a second rod part which are connected in sequence, wherein the rod diameters of the first rod part, the second rod part and a tail rod part are reduced in sequence, and a thread is formed on the second rod part.

10. A multi-step part as claimed in claim 9 wherein a head stem portion is further attached to the end of said flange portion remote from said first stem portion.

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