HK1072915B - Method for the production of hairdresser's scissors, and hairdresser's scissors - Google Patents

Description

The invention relates to a process for the manufacture of a hair clipper as claimed 1 and also a hair clipper as claimed 8 in general.

The scissors are usually made of two shear halves joined by a joint by means of a lock, the two shear halves and therefore the shear are often made of stainless steel alloys or stainless steel alloys. However, such shears have the disadvantage that they lose sharpness after a relatively short use in the cutting area. For this reason, it is also known to apply layers of hard metal in the cutting area. This can significantly extend the life of the shearers, while the cutting edge of the hard sheet remains sharper due to the longer cutting wavelength.

In practice, there are different types of scissors which are based on the same basic principle but which are subject to very different requirements depending on the application. For example, a conventional household scissors essentially depends on their low cost availability and the satisfactory result of cutting paper, fabric or the like. In addition, there are, for example, surgical scissors, which make targeted cuts in hard-to-cut body tissues during an operation. These scissors usually have long-lasting long-lasting short-cutting, in order to achieve favorable leverage ratios and are made of highly trained materials which are also particularly resistant to corrosion and sterilization.The use of scissors in this area has proved particularly successful because scissors are subject to very high frictional corrosion in the cutting area, since the scissors cannot be oiled after sterilization for hygienic reasons. However, since only isolated cuts are allowed in operations, the unfavourable frictional conditions on the cutting edges of the scissors are also of great importance in the operation of the scissors under unfavourable conditions.

The use of scissors for medical purposes is known, for example, from DE 197 33 035 A1. These scissors have two interchangeable shears made of a ductile metal and a wear-resistant material. The wear-resistant material of the scissors is welded into a rectangular depression on a shear sheet so that the material fills the depression completely. Then, a common flat inner surface and an outer surface are cut by grinding, with these surfaces continuously passing from the material of the shear sheet into the welded material.

DE 32 19 260 A1 describes a method for introducing a hard material into a stressed area of the base of a surgical instrument, such as a scissor, and a surgical instrument for that purpose. The hard material is applied by a welding process to a base which is in a clamping device. After the welding worm is applied, the base of the welding worm is subjected to a thermal hardening process at 1100°C followed by abrasion. The abrasion process is followed by grinding the welding worm and the tip of the base into its final shape, also forming the cutting edge.

The ease of use of the scissors is of paramount importance for hair cutters, since they are the main work equipment for a hairdresser or a hairdresser. They are used extensively during the course of a working day and require many hundreds or even thousands of individual cuts to be made every day.

In particular, it is known from practice to interlock the shears in such a way that the two cutting edges are always in contact with each other at exactly one point when a cut is made, whereby this point of contact moves further towards the front of the shear as the shear halves are increasingly closed. This interlocking of the shears is achieved by twisting them around their longitudinal axis and bending them against each other. This arrangement of conventional shearers is carried out in the hardened and compressed state, whereby the equal shear stress of the two cutting edges is therefore slightly affected and optimized by a hammer.

In addition, the manufacture of such trained scissors is therefore very complex, which is why they are very expensive, and they are also very sensitive, since even a single fall on the floor can cause deformation of the shears, which even in the case of a slight deformation already leads to a massive deterioration in the running properties of the two cutting edges.

The hard metal is applied in a thermal spraying process in a layer to a base material and then sanded to obtain the sliding surface and the cutting edge. By ordering such a wear-reducing hard metal layer, the cuts are not as susceptible to wear and are not as quickly blunted as conventional hair cutters. They therefore show a low resistance to closing the scissors in the long run, so that the force applied to the user is also low in the long run.

However, deformation due to mechanical effects, such as when the scissors fall to the ground, usually prevents the use of the scissors with metal cutting known from DE 199 09 887 A1, as the bonding of the sprayed metal layer to the base does not have sufficient stability to allow for post-processing.

The inadequate adhesion of the applied hard metal layer to the base is also the reason why the initial alignment of these conventional hair clippers is problematic, and must be carried out with the greatest care to keep the rate of deformation within limits.

The disadvantage of the hard metal coated hair clippers according to DE 199 09 887 A1 is also that sharpening of the cuts by grinding is usually only possible once, since the material applied is removed and the cutting edge is then made up of the less suitable support material.

The purpose of the invention is therefore to demonstrate a process which allows the manufacture of a lightweight hair clipper with a high durability and mechanical strength, with the possibility of repeatedly finishing the edge of the cutter.

This task is solved from a process-technical point of view with the characteristics of claim 1 and this task is solved by a hair clipper with the characteristics of claim 8.

The method of the invention for the manufacture of a hair clipper as described in claim 1 consists of the following steps: providing a raw material for each of the hair clipper's scissor halves, each having a shear sheet, a straw and a ring; preforming the shears by a predetermined degree of curvature in the direction opposite from the cutting edge; welding a hard metal material in the form of a welding worm to the facing sides of the shears to form the hard metal sheets for the cutting edges; re-closing the pre-determined shear sheet surfaces due to the thermal deformation of the shear sheet during the cutting process; re-forming the welded shear sheet to form a cutting edge, cutting edge and cutting edge, cutting edge and cutting edge, cutting edge and cutting edge, cutting edge and cutting edge, cutting edge and cutting edge, cutting edge and cutting edge, cutting edge and cutting edge, cutting edge and cutting edge, cutting edge and cutting edge.

The present invention shows that, despite the high quality requirements for the shears of a hairdresser's scissors, it is possible to obtain the material for cutting by welding a hard metal material, taking into account the deformation of the raw material due to the thermal effect of the welding process. According to the invention, this is done by preforming the shears, whereby such a pre-set can be reliably performed, since the welding seam is applied completely to the front side of the shear sheet, resulting in a heat transfer and thus a curvature of the cutting material in only one direction. The curvature of the raw material can be reduced by applying some suitable welding action under predetermined conditions.

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The haircutter according to the invention is also characterized by a low wear on the cutting edge, which leads to a prolonged durability with a constant cut-off. In addition, the continuous hard metal layer is also slightly corrosion-prone, which also improves its durability. It is also possible to cut foreign materials without loss of cutting properties. These can also be thin wires, paper or similar materials, since unevenness or damage on the cutting edge of the continuous hard metal can be avoided due to the same cut-off or by re-grinding and possible re-alignment.

The method of the invention is also particularly advantageous in that the welding process creates a particularly good and reliable connection, since in the welding area a sort of alloy is produced from the base material fused with the hard metal material, thus avoiding mechanical and thermal stresses in the material and creating a homogeneous transition between the materials.

A further advantage of the method of the invention is that the welding worm or cutting edge, cut on at least two sides, can be tested for any pores in the hard metal or other welding defects, which can be better detected and thus ensure a significantly higher quality of the product.

The degree of pre-deformation of the shears can also be determined with relatively little effort, for example by sampling each batch of raw materials, taking into account that the degree of deformation may vary slightly from batch to batch, and that the corresponding experimental values can be obtained with little technical effort.

The method of the invention can thus be carried out with high reliability and relatively little technical effort, and in particular it can produce a haircutter with particularly advantageous characteristics.

Beneficial further training of the method of the invention is the subject of dependent claims 2 to 7.

The raw material of a shear half may already be so formed that the hard metal material can be applied directly to the intersecting faces of the shear blades. However, as an alternative, it is also possible, according to claim 2, that material removal from the shear blades before their preforming on the intersecting faces on which the shears are formed is carried out. This material removal can be achieved without further grinding or milling and provides an improved basis for the welding screw of hard metal material to be welded on it. The process according to the invention can thus be carried out with even greater reliability and quality assurance.

In particular, the WIG welding process has proved successful in practical experiments for the welding of the hard metal material, since it can produce a good bond and a high-quality welding worm.

If the welding of the hard metal material is carried out with the aid of a cooled clamping device, the process can be controlled even more precisely, in particular by avoiding damage to the support material from which the shears are formed due to the thermal effect and by better controlling the heat flows.

It is also possible that the hardening of the hair clippers involves hammering the cutting edge, a technique which, despite the poor experience of spraying hard metal layers, has proved to be advantageous for welded hard metal cuts from the finished material, as practical experiments by the applicant have shown, and which is already known in itself and has proved to be effective in the case of conventional hair clippers, thus allowing a good and even running of the two cutting edges with relatively little technical effort.

The surface treatment of the scissor halves involves fine grinding in one or several steps, the inner sides of the shears and the cutting on a cork panel being worked with a polishing lubricant or a polishing paste, which can further improve the lightness of the hairdressing scissors produced by this process. The two shears slide even more easily on each other, thus further reducing the force required to cut.

The surface treatment of the scissor halves is further advantageous if it involves matting the inside of the shears and the cutting with a scotch disc, which may eliminate or reduce small abrasion marks which may still be present after the finishing step, which are also noticeable during the cutting process, so as to no longer affect the smooth running of the shears, and thus also improve the surface's corrosion resistance.

In accordance with another aspect of the present invention, a hair clipper with the characteristics of claim 8 is created, in particular by a process according to one of claims 1 to 7. It is characterized by the fact that the cuts are arranged as if by welding a hard metal and subsequent grinding, on the front sides of the shears, which are facing each other, and are made of full-material elements extending over the entire thickness of the shears.

The hair cutter according to the invention is thus characterized by excellent cutting properties, high resistance to mechanical stress, great durability and, in particular, also by the ability to remain sharp even at sharp cutting angles and to be easily cut if necessary.

The inner sides of the shears and cutting edges are finely cut and matted to improve the lightness of the hair clippers and/or their corrosion resistance.

In addition, a hard metallic material consisting of an alloy based on cobalt has proved to be advantageous in practical experiments, in particular an alloy with 30% Cr, 12% W, 2.5% C and the remainder Co (Stellite 1) which has been shown to have a hardness HRC of 51 to 58 in experiments.

The invention is explained in more detail below by means of examples of execution using the figures in the drawing. Fig. 1 A closed-state hair clipper of the invention;Fig. 2The open-state hair clipper of the invention;Fig. 3A to 3C manufacturing steps in the example of a scissor halves.

As shown in Figures 1 and 2, a hairdresser's scissors 1 has two scissor halves 2 and 3 which are connected to each other via a lock 4 which can be moved. The scissor halves 2 have a ring 21, a beam 22, a scissor blade 23 and a cutter 24. In addition, a blade stopper 25 and a finger support 26 are located on the ring_21. The scissor halves 3 have a ring 31, a beam 32, a scissor blade 33 and a cutter 34.

The manufacturing process for the hair clipper 1 is shown below in Figures 3A to 3C on the example of the scissor halves 2, the process for the scissor halves 3 being the same.

In this case, the two halves of the scissors 2 and 3 are first prepared and worked in the conventional way, in particular, at the beginning of the work, the inner surface of rings 21 and 31 are sanded and polished, and the holes in the two halves of the scissors 2 and 3 are formed by cutting a thread or lowering the screw hole on the counterpart for the screw-like lock.

As shown in Fig. 3A, a raw material is first provided for the cutter 2 and the cutter 23 is removed from the area where the cutter 24 is formed, and the cutter 23 is then deformed to the point where it is bent away from the cutter in the direction opposite to the position shown in Fig. 3A. The degree of this deformation corresponds to a degree of deformation of the cutter as determined by previous experiments due to the heat effect of the subsequent welding process.

As shown in Fig. 3B, a hard metal material in the form of a welding worm 5 is then applied to the corresponding front surface of the shear sheet 23 by a WIG welding process. From this welding worm 5 the cutting edge 24 is then formed by a grinding step. The adjacent surfaces of the shear sheet 23 and the cutting edge 24 are then cut together to produce a fluid transition. This is particularly important on the inside of the cutting edge 23 facing the shear sheet 24 as these edges can slide together.

In the case of the scissor halves 2 thus produced, the scissor blade 23 and the cutter 24 are thus closely connected, the softer material of the scissor blade 23 allowing the haircutter 1 to be aligned precisely in the assembled state, and the good wear resistance of the hard metal material of the cutter 24 ensuring a long service life with a consistently good cut.

The alignment step concerns in particular the course and shape of the cut 24 or 34 or the cut blades 23 or 33, respectively, and the rings 21 or 31 and the branches. The rings are also bent into the desired shape or angle of attachment to the main plane of the scissors so that they are as close as possible to the hand. Finally, the numbering of the scissor halves 2 and 3 is followed to ensure their alignment and a pre-grinding of the shape on the hairdresser's scissors.

The inner part of the shears 23 and 33 is then polished with a cork plate with a polishing paste, as well as the end of the shears 2 and 3. These are then connected and then hardened. The gear is polished, the forming is optimized, especially with regard to the position of the two shears 23 and 33 together, and also with regard to the position of the rings 21 and 31.

In a subsequent step, the two scissor halves 2 and 3 are then separated from each other again and surface treated again by brushes using a brush disc and brush enamel. This is followed by a cleaning step of the parts.

The scissors are then cleaned again, and the halves 2 and 3 are connected again to the parts according to the numbers assigned to each other. The scissors 1 are then finished, the screw serving as lock 4 is properly tightened so that the screw shaft is firmly fixed in the thread and the gear is directed.

In the present embodiment, this is followed by a gold plating step on parts of the scissors 1, whereby the gold plates are glued with an adhesive tape or similar, the screw is polished and filtered, and the screw and the scissor halves 2 and 3 are gold plated after a further cleaning step.

The blade stopper 25 and the finger rest 26 are then attached and a new gait check and, if necessary, a sharpening of the cutting 24 and 34 is carried out, followed by a cutting check and a quality check of the whole product, which is then oiled to prevent corrosion, and the scissors are then wiped, packed and ready for shipment.

The invention allows for further design approaches in addition to the illustrated embodiment.

Thus, the hair clipper 1 according to the invention, in the twisted state, can be prepared first by itself with a hammer in the conventional way, in order to obtain a certain degree of advantageous accuracy and precision.

In addition, the grinding step of the shears 23 and 33 and the cutting step 24 and 34 may be followed by a fine grinding step in one or several steps, in which the interfaces of the shears 23 and 33 and the cutting sheet 24 and 34 are reworked on a cork panel, e.g. 20 mm thick, at 1200 r/min using a special, very fine polishing lubricant.

In addition, the inside of the shears and the cutting edges can be matted with a scotch disc in a further step of the process, in order to eliminate or reduce small marks of abrasion which may still be present after finishing or polishing, so as to prevent them from affecting the shear flow.

The grinding and/or matting steps provided for in the method of the invention can also be used to the advantage of the area of the scissor halves 2 and 3 around the slot 4, in which they slide on and against each other.

In addition to the WIG welding method described above, other welding methods can be used to apply the welding worm from a hard metal material, with the preference being given to a protective gas welding method such as WP, MIG or MAG welding.

In practical experiments, an alloy based on cobalt has been used as a material for the hard metal. Stellites are used as an advantage, with hard metal with a hardness HRC in the range of 50 to 60 having proven particularly good.

Claims (9)

1. A method for manufacturing barber scissors (1) wherein edges (24, 34) of hard metal are arranged on the scissor blades (23, 33), comprising the steps:

   - furnishing one blank each for scissor halves (2, 3) of the barber scissors (1), with the scissor halves (2, 3) each comprising a scissor blade (23, 33), a shank (22, 32), and a ring (21, 31),

   - pre-shaping the scissor blades (23, 33) by a predetermined degree of curvature in the direction facing away from the edge (24, 34),

   - welding on a hard metal material in the form of a welding bead (S) on the respective mutually facing faces of the scissor blades (23, 33) in order to form the hard metal layers for the edges (24, 34), wherein the predetermined pre-forming of the scissor blades (23, 33) is substantially neutralized owing to the influence of heat during the welding process,

   - grinding of the welding beads (S) so as to form the edges (24, 34),

   - combining and subsequently setting the scissor halves (2, 3),

   - disassembly and subsequent hardening of the scissor halves (2, 3),

   - surface treatment of the scissor halves (2, 3),

   - again combining the scissor halves (2, 3), and

   - hard-setting the barber scissors (1).
2. The method in accordance with Claim 1, characterized in that prior to pre-forming of the scissor blades (23, 33), a removal of material is performed on the scissor blades (23, 33) on their mutually facing faces on which the edges (24, 34) are to be formed.
3. The method in accordance with Claim 1 or 2, characterized in that welding on of the hard metal material is performed with a TIG welding process.
4. The method in accordance with any one of Claims 1 to 3, characterized in that welding on of the hard metal material is performed with the aid of a cooled clamping device.
5. The method in accordance with any one of Claims 1 to 4, characterized in that hard-setting of the barber scissors (1) includes pre-setting by mean of hammer blows.
6. The method in accordance with any one of Claims 1 to 5, characterized in that the surface treatment of the scissor halves (2, 3) includes a fine-grinding in one step or in several steps, wherein the insides of the scissor blades (23, 33) and of the edges (24, 34) are worked on a cork disc by using a polishing paste.
7. The method in accordance with any one of Claims 1 to 6, characterized in that the surface treatment of the scissor halves (2, 3) includes matting of the insides of the scissor blades (23, 33) and of the edges (24, 34) by means of a Scotch disc.
8. Barber scissors (1) comprising two scissor halves (2, 3) each including a scissor blade (23, 33), a shank (22, 32), and a ring (21, 31) and articulatedly coupled with each other in an articulation by means of a lock (4), and including edges (24, 34) of hard metal on the scissor blades (23, 33), characterized in that the edges (24, 34) are formed as massive elements extending over the entire thickness of the scissor blades (23, 33) on mutually facing faces of the scissor blades (23, 33), which are formed by welding application of a hard metal and a subsequent grinding step, and in that the insides of the scissor blades (23, 33) and of the edges (24, 34) have a fine-ground and matted surface in order to improve easy movement of the barber scissors.
9. The barber scissors in accordance with Claim 8, characterized in that the hard metal of the edges (24, 34) is comprised of a cobalt-based alloy such as, e.g., an alloy including 30% of Cr, 12% of W, 2.5% of C and the remainder Co, which has a hardness HRC of 51 to 58.