Method for drawing wire for staples

Abstract

There is a method for the production of stapling wire for use in the graphic industry for stapling periodicals, brochures and the like. A drawable wire is drawn from an initial material (A) having a low carbon content which is drawn in a first drawing step from a starting diameter (D1) to a temporary diameter (D2). This wire is drawn in a second drawing step from the temporary diameter (D2) to a final diameter (D3), so that a stapling wire results. This process provides a simple and economical method for producing stapling wire, wherein stapling wire is produced to fulfill the requirements of the graphic industry. In addition, this second drawing step is performed without previously subjecting the wire to a heat treatment.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for the production of stapling wire for use in the graphic industry for stapling periodicals, brochures, and the like. The method involves drawing a wire from an initial material in a first drawing step from an initial diameter to an intermediate diameter. The wire is redrawn in a second drawing step from the intermediate diameter to a final diameter, to form the stapling wire.

[0003] 2. The Prior Art

[0004] Methods of the type initially described are already known in practice. In a known method, the starting material, which typically has an initial diameter of approximately 5.5 mm, is drawn in a first drawing step to an intermediate diameter of 2.2 mm. Subsequently, this wire is annealed, so that, after a subsequent galvanizing stage, it can be wet drawn to the desired final dimension, which typically is in the range from 0.3 to 0.7 mm.

[0005] While the galvanizing step immediately follows the annealing step in the known method cited, in another method known from practice, the wire drawn to the intermediate diameter is coiled up after the first drawing step and heat-treated in the coiled state. Subsequently, the wire having the intermediate diameter is galvanized, with the wire being uncoiled and recoiled after galvanizing, which is typically done electrolytically. These steps are followed by the step of wet drawing to the final diameter.

[0006] The stapling wire produced based on this method is finally coiled after the second drawing step and supplied to the graphic industry. Printers and similar operations are meant by the graphic industry, who use the stapling wire to staple together periodicals, brochures, and the like. For wire stitching and/or stapling of periodicals, the wire is successively pulled off and cut from the coil and/or the spool at the printers. Subsequently, the cut wire pieces are bent so that individual staples result, which are then stapled into the backs of individual periodicals.

[0007] To staple periodicals at the printers rapidly and without problems, the stapling wire must have very specific properties. These include the wire being relatively hard to penetrate the backs of the periodicals without problems, but also being easily shapeable into a staple. In addition, the wire and/or the staples produced from it must keep their shape after the stapling method. For example, the wire must not unbend, which not only interferes with the stapling, but also can lead to injuries if a reader passes his hand over the point of a staple. Another essential requirement of the stapling wire is that it can be cut well. It is important during cutting that no so-called flags form on the cut ends of the wire. These flags are pointed regions which project from the actual cut faces. These flags can lead to the stapling wire not penetrating the backs of the booklets perpendicularly during stapling, but going in at an angle, so that correct stapling is not possible.

[0008] It is known from Hirschfeld, M.: Drahtziehen I. (Wire Drawing I.) in: Werkstatt 328, Carl Hanser Verlag, Munich, 1964 that the material requirements of the wire increase hyper-proportionally during wire production in large total reduction of the wire cross-section. To reduce these requirements, it is possible to reduce the cross-section in multiple steps. However, this measure leads to an uneconomically high number of individual steps by larger total reduction. Thus, heat treatments before, during and after improve the formability of the work material. The method engineering effort, however, also increases through this heat treatment. Moreover, heat treatments lead to additional costs.

SUMMARY OF THE INVENTION

[0009] One object of the present invention is to provide a method for the production of stapling wire that can be performed simply and economically and with which a wire can be produced that fulfills the requirements placed by the graphic industry without any additional steps required.

[0010] The previously indicated and derived object is achieved by using a method of the type initially cited. Essentially the wire does not undergo any heat treatment during the drawing process from a starting diameter to a final diameter. According to the invention, the production of a stapling wire corresponding to the requirements in the graphic industry, provides an improved wire with no heat treatments. Leaving out the heat treatment reduces the production time of the wire and also reduces the production costs, because the heat treatment creates a significant portion of the overall production costs.

[0011] There are numerous product advantages as well. Specifically, the stapling wire produced according to the method of the invention has better properties for stapling periodicals and similar items than a stapling wire produced from the same starting material according to a method of the prior art. The stapling wire produced from the inventive method can, on one hand, be shaped very well, but, in addition, keeps its shape exceptionally well after stapling, so that unbending of the wire after stapling is not a concern.

[0012] In addition, the stapling wire according to the invention is very hard, which is very important, particularly when stapling of thick periodicals. Therefore, a thinner wire can be used, which is more economical, than in the prior art. In addition, the stapling wire of the invention can be cut very well so that no flags result. This can be clearly explained in that the wire produced according to the method can almost be called brittle, so that a flat cut surface without flags results during the cutting of the wire.

[0013] The method according to the invention leads to very good results in wires in which the starting material has a relatively low carbon content of less than 0.1 weight-percent, particularly less than 0.06 weight-percent.

[0014] A starting material can be used which permits a reduction in cross-section from the starting diameter to the final diameter of more than 80%, preferably more than 99%. Depending on the diameter, a reduction in diameter by a factor of up to 100 is possible. Typically, a wire with a starting diameter of less than 10 mm is used as the starting material. Currently, wires with a starting diameter of approximately 5.5 mm are frequently used in practice.

[0015] The final diameter is to be less than 1 mm and is currently between 0.7 and 0.3 mm in practice, depending on the requirements of the client.

[0016] To protect the stapling wire from corrosion or to fulfill specific requirements of the client, a metallic coating is applied as a surface finish to the stapling wire. In the method according to the invention, this coating can be provided as an intermediate coating between the first and second drawing steps. The intermediate coating before the redrawing in the second drawing step leads to a stapling wire onto which the coating adheres particularly well when the staples are produced from the stapling wire and then inserted in the periodicals, brochures, or the like. However it is also possible to apply the coating as a final coating, such as after the second drawing step. However, this coating requires separate cleaning of the wire to ensure good adhesion of the coating to the wire.

[0017] Besides copper, nickel, or tin coatings, which are possible in principle in addition to other coatings, the wire should be galvanized between the first and second drawing steps.

[0018] The first drawing step should be performed with the dry drawing process. In this drawing step, multiple drawing dies with smaller and smaller diameters are typically used. The second drawing step can be performed with wet drawing, or also with the dry drawing process. In contrast to the dry drawing process, the wire is guided through a bath before and/or during drawing in the wet drawing process.

[0019] A dry lubricant is preferably used to lubricate the wire when the drawing in the first drawing step. This lubricant, used in the first drawing step, should be cleaned off of the wire after the first drawing step and before coating, to essentially completely remove the dry lubricant. The surface cleaning could be performed with mechanical cleaning.

[0020] However, the wire should be washed off using chemicals, such as solvents. In addition, the chemical cleaning should be combined with the mechanical cleaning.

[0021] Although it is possible to perform the first and second drawing steps in one single process step, the wire should be coiled up at least once between the first and second drawing step. The first and second drawing steps can be performed independently from one another so that it is not necessary to adjust the drawing speeds of the two drawing steps to one another. However, it is also favorable from a manufacturing technology viewpoint to keep the two drawing steps separate from one another because, if one of the drawing steps breaks down, the other can be operated without any further measures.

[0022] In addition, the first drawing step, the coating step, and the second drawing step, are process steps independent from one another, between each of which the wire is coiled up, to be able to ensure the independence of the individual steps.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings which disclose at least one embodiment of the present invention. It should be understood, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the invention.

[0024] In the drawings wherein similar reference characters denote similar elements throughout the several views:

[0025] FIG. 1 shows a schematic illustration of the method based on the prior art for the production of stapling wire,

[0026] FIG. 2 shows a schematic illustration of the method according to the invention for the production of stapling wire;

[0027] FIG. 3 shows a schematic illustration of a further embodiment of the method according to the invention, and

[0028] FIG. 4 shows a stress-strain diagram from which the properties of stapling wire of the prior art are compared to the stapling wire produced from the method according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0029] Referring to the drawings, FIG. 1 shows the prior art process for the production of stapling wire which is intended for use in the graphic industry for stapling of periodicals and the like. A drawable wire serves as the starting material A, which possibly has been previously mechanically and/or chemically descaled. Subsequently, the starting material A is drawn in a first drawing stage B with multiple drawing dies to a smaller intermediate diameter. The drawn wire is then coiled up in stage C. Following this step, the wire is then annealed in stage D, i.e. subjected to a heat treatment. Immediately following this step, the wire is galvanized in stage E.

[0030] In another known method, not shown, steps D and E can also be separate steps, between which the wire is again coiled up.

[0031] Following step E the wire is coiled up again in step F and then supplied to the second drawing step G, where the wire is redrawn to the desired final dimensions, so that in step H, a coiled-up stapling wire h results with the desired final diameter.

[0032] The method according to the invention is schematically illustrated in FIG. 2. A wire with good drawing properties having a low carbon content serves as the starting material 1, which, is first cleaned for descaling in a cleaning device. This wire is supplied to a first drawing step 2. The wire of the starting material 1 has a starting diameter D1. In the first drawing step 2, the wire of the starting material 1 is drawn to a wire with an intermediate diameter D2. For this purpose, there is a first drawing device with multiple drawing dies having smaller and smaller diameters. While the starting diameter D1 of the present wire is approximately 5.5 mm, after the first drawing step 2, the wire has an intermediate diameter which typically varies between 1.4 mm and 3.2 mm.

[0033] The wire is then coiled up in step 3 via an appropriate coiling device. In step 4, the wire is coated with an appropriate coating device. In the present case, the wire is galvanized for surface finish. In principle, it is also possible to perform steps 2 and 4 in one line, without coiling in step 3. In the embodiment illustrated, the previously coiled wire is uncoiled via an appropriate coiling device and fed through an appropriate bath of the coating device. This wire is then electrolytically galvanized. In principle, hot galvanizing would also be possible. Following this step, the galvanized wire is then coiled up again in the step 5.

[0034] The galvanized wire with the intermediate diameter D2 is then supplied to a second drawing step 6, whose final product is the stapling wire 7 with the desired final diameter D3. There is also a second drawing device with multiple drawing dies having diameters which become smaller and smaller. The stapling wire 7 is then coiled up again via an appropriate coiling device, which occurs in step 8.

[0035] The method schematically illustrated in FIG. 2 for the production of stapling wire 7 is completely without heat treatment. However, a stapling wire 7 is nonetheless produced which has excellent properties for the intended purpose of stapling periodicals.

[0036] As already mentioned, steel with a low carbon content, particularly less than 0.06 weight-percent, is used as the starting material 1 to ensure good drawing properties of the starting material 1. Thus, it is possible to draw the wire from a starting diameter D1 of 5.5 mm down to 0.7 mm or 0.2 mm without any heat treatment.

[0037] In the schematic illustration according to FIG. 2, step 4 involves a galvanization bath. In principle, it is also possible to provide other coating devices, or, in specific applications, to dispense with the coating completely.

[0038] In the embodiment illustrated, the first drawing step 2 is performed with the dry drawing process, while the second drawing step 6, due to the preceding surface finish, is performed with the wet drawing process. Dry drawing typically requires the use of an appropriate dry lubricant. In this context, it is particularly favorable to provide, following the first drawing step 2, a step 9 (FIG. 3) for surface cleaning of the wire for preferably complete removal of the dry lubricant. An appropriate surface-cleaning device is provided for this purpose. This step ensures that no dry lubricant residue remains on the wire when the coating is performed in step 4, so that the coating adheres well on the staples produced from the wire. Otherwise, the method illustrated in FIG. 3 corresponds to that in FIG. 2.

[0039] In FIG. 4, a stress-strain diagram is illustrated which, shows the stress-strain properties of the stapling wire 7 formed by the process according to the invention and compares this curve to a stapling wire h produced according to the method of the prior art. It can be seen that stapling wire 7 is harder, but definitely keeps its shape after bending. Furthermore, stapling wire 7 can also be cut very well, so that problems in the stapling of periodicals or similar items are not a concern. The values of the diagram indicated on the abscissa are only applicable for one preferred embodiment of the wire produced according to the method according to the invention, but other value ranges are also possible without any further measures.

[0040] Accordingly, while at least one embodiment of the present invention has been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for the production of stapling wire in the graphic industry comprising:

providing a wire having a good starting material with a low carbon content and having a starting diameter D1;

drawing said wire from said starting diameter D1 to an intermediate diameter D2; and

redrawing said wire from said intermediate diameter D2 to said final diameter to produce said stapling wire wherein said reduction in cross-sectional diameter of said wire is greater than 80% wherein said wire does not undergo any heat treatment during the drawing process from said starting diameter D1 to said final diameter D2.

2. The method as in claim 1, wherein said step of providing a wire includes providing a wire with a starting material with a carbon content of less than 0.6%.

3. The method as in claim 1, wherein said step of redrawing the wire draws the wire to a final diameter D(3) that is greater than 99% reduced in diameter from said starting diameter D1.

4. The method as in claim 1, wherein said step of providing a wire includes providing a wire having a starting diameter of less than 10 mm.

5. The method as in claim 1, wherein said step of providing a wire includes providing a wire having a starting diameter of less than 5.5 mm.

6. The method as in claim 1, wherein said step of redrawing the wire redraws the wire to less than 0.7 mm.

7. The method as in claim 1, further comprising the step of applying a metallic coating to the wire as a surface finish between said first drawing step and said second drawing step.

8. The method as in claim 7, wherein said wire is galvanized.

9. The method as in claim 1, wherein said first drawing step is performed with a dry drawing process.

10. The method as in claim 1, wherein said second drawing step is performed as a wet drawing process.

11. The method as in claim 1, wherein said second drawing step is performed as a dry drawing step.

12. The method as in claim 1, further comprising the step of adding a dry lubricant to said wire before said first drawing step and cleaning said wire to remove said lubricant.

13. The method according to claim 1, further comprising the step of coiling the wire between said first drawing step and said second drawing step.

14. The method as in claim 13, further comprising the step of applying a coating to the wire after the first drawing step wherein said wire is coiled up after the application of said coating.

15. The method as in claim 1, wherein said second drawing step is performed without said wire having been coiled following the first drawing step.