Medical clip, remolding tool, remolding machine, and method for manufacturing medical clip

Abstract

In order to improve medical clips, in particular in the form of aneurysm clips, it is proposed that the cone angle has a value of at least 10°. Additionally, an improved reforming tool, an improved reforming machine, and an improved method for manufacturing medical clips are proposed.

Description

Summary of the Invention

[0001] The present invention relates to a medical clip, in particular in the form of an aneurysm clip, comprising two cooperating clamping arms and a biasing element having two ends, each of the two clamping arms being connected to one end of the biasing element via a connecting portion, in a base position of the medical clip the two clamping arms are maximally close to each other, in particular abutting each other, and are movable away from each other against the action of the biasing element from the base position to an open position, the two connecting portions defining a first circular cross section with a first diameter, the biasing element defining a second circular cross section with a second diameter, the second diameter being smaller than the first diameter, the connecting portions tapering towards the biasing element such that a conical transition region is formed, the conical transition region defining a cone angle.

[0002] The invention further relates to a reforming tool, in particular a swaging tool, for reforming a wire blank, in particular to form a medical clip, the reforming tool comprising a base body defining a longitudinal direction, on which is formed at least one molding element extending at an infeed angle relative to the longitudinal direction.

[0003] The present invention also relates to a reforming machine, in particular a rotary swaging machine.

[0004] The present invention further relates to a method for manufacturing a medical clip, particularly in the form of an aneurysm clip, comprising reshaping, particularly by rotary swaging, a wire-like blank having a first circular cross-section and a first diameter, said reshaping forming an intermediate portion having a second circular cross-section and a second diameter between two undeformed end portions of the blank, said reshaping forming at least one conical transition region between the undeformed end portions and the intermediate portion.

[0005] Medical clips of the type mentioned at the outset are used in particular in the form of aneurysm clips for treating sacs in hollow organs such as blood vessels. In order to increase the elastic range of the biasing element of such medical clips, it is known to modify the structure of the part forming the biasing element of the medical clip by reshaping. By such cold hardening, the yield strength of the metallic material from which the medical clip is formed can be increased. As a result, the opening width of the medical clip can be increased. For reshaping, in particular, a rotary swaging process is used.

[0006] Known rotary swaging processes and reshaping tools and machines used therefor are known, for example, from DE Utility Model 20309632. With such reshaping tools, in particular swaging tools, only transition regions with very small cone angles can be produced. With plunge (piercing) and / or feed rotary swaging with known reshaping tools, only limited deformation rates (i.e. ratio of second diameter to first diameter) can be achieved. Furthermore, the magnitude of the cone angle also influences the size of the aneurysm clip. The larger the cone angle, the smaller the transition region between the biasing element and the respective connecting part. The shorter this transition region, the closer the biasing element can be positioned in relation to the clamping arm.

[0007] In known reshaping tools, the shaping element is configured with a profile that defines a cross section of a hollow cylindrical surface. Such a configuration of the reshaping tool limits the possibilities of rotary swaging reshaping. For this, in particular, the deformation rate (hereinafter also called reduction rate) is predetermined. The greater the deformation rate, the greater the quality loss. This is because, when the reshaping tool is pressed into the blank for cold hardening, the material forming the blank can flow into the gaps between adjacent reshaping tools and a burr can form there. The formation of a burr in the transition area, especially for medical clips, is highly undesirable. It may become necessary to remove such a burr in further processing steps, for example by machining or grinding to make it smooth. However, such processing affects the quality and strength of the medical clip.

[0008] SUMMARY OF THE PRESENT EMBODIMENTS It is therefore an object of the present invention to provide improved medical clips, reshaping tools, reshaping machines and methods for manufacturing medical clips, particularly for forming compact medical clips of high quality.

[0009] According to the invention, this object may be achieved in a medical clip of the type described above in that the cone angle has a value of at least 10°.

[0010] Conventional reshaping tools are not capable of producing such cone angles. With a cone angle of at least 10°, the transition area is reduced by almost 50% compared to cone angles known from the prior art (maximum of about 7° for medical clips). This is due to the symmetrical configuration of the molding elements in the known reshaping tools. This allows a more compact medical clip to be produced.

[0011] Advantageously, the cone angle has a value of at least 15°. In particular, it may have a value of at least 20°. The larger the cone angle, the shorter the transition area between the connecting part and the biasing element. Thus, the biasing element, for example in the form of a coil spring, can be closer to the clamping arm. This is particularly advantageous for medical clips used in neurosurgery.

[0012] It is preferred if the first circular cross section defines a first cross-sectional area and the second circular cross section defines a second cross-sectional area, the ratio of the second cross-sectional area to the first cross-sectional area being at most 0.7. In particular, said ratio may be at most 0.5. The specified ratio in particular predetermines the properties of the biasing element. The greater the deformation rate dε, i.e. the greater the ratio dA / A0 of the change in cross-sectional area dA (i.e. the difference between the cross-sectional area A1 after reshaping and the cross-sectional area A0 before reshaping) to the cross-sectional area A0, the greater the increase in yield strength and the more elastic the biasing element becomes. With the known reshaping tool, only medical clips having a cross-sectional area ratio exceeding 0.7 can be reshaped. This corresponds to deformation rates in the range of -0.3 to 0.

[0013] Preferably, the conical transition area is formed exclusively by reshaping, in particular by rotary swaging. This has the advantage that in the manufacture of the medical clip, the transition area can be formed in a single work step, for example by rotary swaging. No post-processing, such as grinding off burrs, is necessary. This can be easily verified on the basis of the geometrical and microstructural properties of the medical clip. In particular, a microstructural analysis can clearly determine whether the conical transition area was formed exclusively by reshaping or whether it was additionally altered by grinding or machining to make it smooth after reshaping.

[0014] Advantageously, the biasing element is formed exclusively by reshaping, in particular by rotary swaging. Such medical clips are of high quality. They can also be easily manufactured, since the biasing element can be formed exclusively by reshaping. This process reduces the cross section of the blank forming the medical clip in the region of the biasing element (also called the intermediate portion between the ends of the blank). This intermediate portion can be, for example, spring-wound. However, no rotary swaging process is performed here.

[0015] Advantageously, the conical transition region is not ground. Such a medical clip can be formed without grinding the transition region and without the occurrence of burrs in the transition region. This is possible in particular with cone angles as specified above. In known medical clips, such cone angles cannot be achieved by reshaping alone, in particular by rotary swaging alone. Moreover, with conventional reshaping tools, the formation of burrs in the transition region cannot be substantially avoided.

[0016] Preferably, the biasing element is unpolished, so that the biasing element can be formed to a high quality without adversely affecting the structure of the material through grinding (polishing) or other machining processes.

[0017] Particularly stable medical clips can be formed, for example, by integral, particularly monolithic construction, for example, from a single blank by correspondingly reshaping different portions of the blank to form the clamping arms, connectors, and biasing elements.

[0018] In order to move the clamping arm in a defined manner from the base position to the open position and back from the open position to the base position by the biasing element, the biasing element is advantageously configured in the form of a coil spring having at least one complete winding (one turn). The biasing element may in particular have a complete winding with two, three or more turns. In particular, the spring constant of the biasing element can be predetermined by the number of turns.

[0019] According to a further preferred embodiment, the clamping surfaces of the clamping arms define clamping surface planes, which may be configured to be oriented parallel to one another in the basic position. Such an embodiment of the clip allows, for example, a secure placement of the clip in hollow organ sacs in the human or animal body, in particular in so-called aneurysms.

[0020] According to the invention, the object stated at the outset is further achieved in that in a reshaping tool of the type stated at the outset, at least one shaping element has an asymmetric configuration relative to a central plane of the base body which includes the longitudinal direction.

[0021] Such a configuration of the reshaping tool makes it possible to prevent or substantially prevent the formation of burrs on the workpiece during rotary swaging, especially in the case of hollow cylindrical shapes. In particular, the asymmetric configuration makes it possible to directly deform the burrs that are usually formed when the workpiece and the reshaping tool rotate in correspondence. This is achieved in particular in that at least one molding element has a profile only on a part of its reshaping surface, like the conventional molding elements of known reshaping tools, which profile has an inner diameter that corresponds to the workpiece to be reshaped. However, the asymmetric design of the reshaping tool makes it possible to design an area of ​​the molding element in such a way that the radius or shape of the molding element does not completely match (contact) the workpiece to be reshaped. This area allows the material to be continuously deformed when the blank is deformed, by rotating the reshaping tool and the workpiece to be processed relative to one another, so that no burrs are formed. Such a reshaping tool can be used in particular for plunge and / or rotary swaging. In particular, it makes it possible to achieve a larger cone angle in the transition area than before, without the formation of burrs or other negative deformations that affect the quality of the workpiece. The cone angle at the transition region on the workpiece is predetermined by the infeed angle of the reshaping tool.

[0022] The infeed angle advantageously has a value of at least 10°. In particular it may have a value of at least 15°. In particular it may have a value of at least 20°. With such a reshaping tool, the workpiece can be formed in the manner described above (for example exclusively by rotary swaging) without burrs in the region of the blank where the cross section has been reduced, and also without burrs in the transition region.

[0023] In order to form a workpiece having a minimum cross-section in a specified manner, it is preferred that a calibration area is formed in the base body, the calibration area extending parallel to the longitudinal direction or defining the longitudinal direction.

[0024] For reasons already explained, it is preferred that the calibration area be asymmetric with respect to the mid-plane, so that the calibration area can guide the workpiece to the desired final shape.

[0025] According to a further preferred embodiment, the moulding element defines, in a cross section perpendicular to the longitudinal direction, a curved section line having a first end and a second end, the curvature of the section line having a maximum value at the first end and a minimum value at the second end. Such a configuration of the moulding element makes it possible in particular to deform the workpiece into a shape having a desired radius in the region of the first end. The maximum value of the curvature corresponds to the minimum value of the radius of the section line in the region of the first end. The above-mentioned curved extension of the section line thus allows the reshaping tool to be continuously forged into the workpiece when the reshaping tool and the workpiece are in contact with each other in succession at different rotational positions.

[0026] It is preferred if the curvature of the section line is zero at the second end, which means that the section line extends in a straight line in the region of the second end, thereby obtaining in particular a flat region of the moulding element for deforming the workpiece.

[0027] It is advantageous if the curvature of the section line decreases continuously from the first end to the second end, which allows to obtain a section line in the form of an involute having a minimum radius in the region of the first end and a maximum radius in the region of the second end, the radius of the first end being not smaller than the radius of the finished workpiece.

[0028] Furthermore, it is advantageous if the curvature of the section line is constant over a forging angle area defined relative to the longitudinal direction, starting from the first end. As already mentioned, it is possible to obtain a region of the forming element corresponding to a conventional forming tool. However, the difference with respect to the conventional forming tool is that the curvature is constant only in the forging angle area and changes from the forging angle area towards the second end.

[0029] Advantageously, the curvature of the cut line between the forged angle region and the second end is smaller than the curvature of the cut of the forged angle region, which allows asymmetric reshape elements to be produced in a simple manner.

[0030] The curvature of the section line preferably decreases from the forged angular region towards the second end. In particular, the curvature of the section line may decrease continuously. Alternatively, the curvature of the section line may decrease in one step. In that case, the forged angular region defines a first radius and the region between the forged angular region and the second end of the section line defines a second radius that is greater than the first radius, i.e. has a curvature that is less than the maximum curvature in the forged angular region.

[0031] To achieve the so-called "roof shape" of the reshaping element, it is advantageous if the curvature of the cross-sectional line is constant from the forging angle area to the second end, so that the shaped element can be formed by a combination of partial areas that correspond to conventional reshaping tools and flat partial areas.

[0032] In order to obtain a flat area between the forged angle area and the second end, it is advantageous if the curvature of the cutting line is zero from the forged angle area to the second end.

[0033] According to a further preferred embodiment, the forging angle region extends over a circumferential angle in the range of about 5° to about 90° relative to the longitudinal direction. In particular, the circumferential angle may be in the range of about 10° to about 50°. Such a forging angle region allows an optimal deformation of the workpiece.

[0034] Furthermore, it is preferred that the curvature at the first end of the cross-sectional line in the in-feed area increases in the direction of the calibration area, in particular continuously. In other words, this means that the curvature at the first end of the cross-sectional line in the in-feed area close to the calibration area is greater than the curvature at the first end of the cross-sectional line further away from the calibration area. This allows the cross-section of the workpiece to be continuously reduced by repeated contact of the workpiece with the reshaping tool and its shaping elements.

[0035] According to the invention, the initially stated object is further achieved with a reshaping machine comprising at least one reshaping tool as described above.

[0036] In particular, the reshaping machine may comprise two, three, four or more reshaping tools, which are in particular arranged to be movable in the longitudinal direction. They can therefore be moved towards the workpiece in order to deform the shape, and can be moved slightly away from the workpiece in order to release it, and the reshaping tools and the workpiece can be rotated relative to one another in the longitudinal direction. The difference between the reshaping machine according to the invention and known reshaping machines lies in particular in the design of the reshaping tools, in particular their asymmetric design.

[0037] According to the invention, the object stated at the outset is achieved in a method of the type described at the outset in that at least one conical transition region is configured to have a cone angle of at least 10°. As already mentioned at the outset, a shorter transition region has the advantage that the biasing element can be moved closer to the clamping arm, which in turn allows the size of the medical clip to be reduced.

[0038] It is advantageous if the intermediate portion is wound to form at least one complete turn to form the biasing element, in particular, winding of the intermediate portion can only take place after the clamping arm has been deformed in the desired manner.

[0039] It is advantageous if the first part of each of the two end parts is reshaped into a clamping arm, the clamping arm extending from the free end of the two end parts. In the manufacture of the medical clip, it is particularly advantageous if the clamping arms are formed before the biasing element is rolled, i.e. when the blank is still elongated after the intermediate part with reduced cross section is formed. The clamping arms can be formed in particular by means of a press tool.

[0040] It is further advantageous if the second part of each of the two end parts is reshaped into a connecting part, each of which connects a clamping arm to one end of the biasing element and in which, in the home position of the medical clip, the clamping arms are maximally close to each other, in particular abutting each other, and are movable away from each other against the action of the biasing element from the home position to the open position. Such a configuration of the connecting parts makes it possible, in particular, to adjust the medical clip in a desired manner. In particular, the biasing force exerted by the biasing element in the home position can also be set. The biasing force can be predetermined in a desired manner by appropriately deforming the connecting parts relative to the clamping arms and the biasing element.

[0041] Preferably, the blank is reshaped using at least one of the above-mentioned reshaping tools to form the intermediate part. This allows the intermediate part and the transition area to be directly deformed, in particular so that no flash is formed. Reworking of the transition area and the intermediate part is therefore not necessary. This is made possible in a simple manner by the asymmetric design of the reshaping tool. Such a reshaping tool allows a cone angle of more than 10° to be obtained in the transition area.

[0042] During reshaping to form the intermediate portion, it is advantageous to rotate the blank and at least one reshaping tool relative to one another about a longitudinal direction defined by the blank when they are out of engagement. By repeatedly opening and closing the reshaping tool, as is typically done in rotary swaging, the blank can be deformed in the desired manner.

[0043] By using any of the above-mentioned remolding machines for remolding, medical clips can be manufactured in a convenient manner.

[0044] To avoid damaging the clip, the at least one conical transition region is preferably formed without grinding, and therefore the transition region is formed solely by rotary swaging.

[0045] Preferably, the at least one conical transition region is formed exclusively by remolding, in particular exclusively by rotary swaging, which allows further processing steps to be avoided, thus simplifying the manufacture of the medical clip and minimizing production costs.

[0046] It is further proposed to use any one of the above mentioned methods for manufacturing any one of the above mentioned medical clips.

[0047] The following description of preferred embodiments will provide a more detailed explanation in conjunction with the drawings. [Brief description of the drawings]

[0048] [Figure 1] 1 is a schematic perspective overall view of an embodiment of a medical clip; [Diagram 2] Schematic showing a portion of the reforming machine with three reforming tools and a blank before the reforming tools are first pressed into the blank. [Diagram 3] FIG. 3 is a schematic diagram of a portion of a reshaping machine similar to that of FIG. 2, with three reshaping tools and a blank, with the reshaping tools of the reshaping machine in contact with the workpiece; [Figure 4] FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. [Diagram 5] 5 is a cross-sectional view taken along line 5-5 of FIG. 3. [Figure 6] 13 is a schematic cross-sectional view through a calibration area of ​​an embodiment of a reshape tool. [Figure 7] 7 is a schematic cross-sectional view similar to FIG. 6 of a further embodiment of a reshaping tool; [Figure 8] 7 is a schematic cross-sectional view similar to FIG. 6 of a further embodiment of a reshaping tool; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] 1 shows a schematic diagram of an example of a medical clip, designated by the reference numeral 10. This is configured in the form of an aneurysm clip 12.

[0050] The clip 10 includes two cooperating clamping arms 14, 16. The clamping arms 14, 16 have free distal ends 18, 20.

[0051] Each clamping arm 14, 16 has a respective clamping surface 22, 24. The clamping surfaces 22, 24 face each other. In a basic position, shown diagrammatically in Figure 1, the clamping arms 14, 16 are as close as possible to each other. In the embodiment shown in Figure 1, the clamping surfaces 22, 24 are in contact with each other.

[0052] The clamping arms 14, 16 define respective clamping face planes 26, 28 that are oriented parallel to one another in a home position. In the embodiment shown in Figure 1, the clamping face planes 26, 28 are coincident.

[0053] The proximal ends 30, 32 of the clamp arms 14, 16, respectively, are adjacent to one another by connecting portions 34, 36. In the embodiment shown in Figure 1, the connecting portions 34, 36 are configured to pass through one another such that the connecting portion 36 has a male connecting element 38 which passes through a female connecting element 40 of the connecting portion 34 to form a box lock (push-through) 42.

[0054] The connecting portions 34, 36 taper towards the ends 48, 50 of the biasing element (pretensioning element) 52 forming conical transition regions 44, 46, respectively. Thus, each of the two clamping arms 14, 16 is connected via the connecting portions 34, 36 to a corresponding one of the ends 48, 50 of the biasing element 52.

[0055] Biasing element 52 is configured in the form of a coil spring 54 and has at least one complete turn. In the embodiment shown in Figure 1, coil spring 54 has approximately 1.5 complete turns.

[0056] Clip 10 is integrally or monolithically constructed from a metal wire blank 56. The manufacture of clip 10 is described in detail below.

[0057] The linking portions 34, 36 define a first circular cross-section 64 having a first diameter 58. The biasing element 52 has a second circular cross-section having a second diameter 60. The second diameter 60 is smaller than the first diameter 58.

[0058] The conical transition regions 44, 46 define a cone angle 62 having a value of at least 10°. In embodiments not shown, the cone angle 62 is at least 15° or at least 20°.

[0059] The first circular cross-section 64, which defines the first diameter 58, defines a first cross-sectional area due to its circular shape. The second circular cross-section, which is defined by the second diameter 60, therefore defines a second cross-sectional area. In the clip 10 shown diagrammatically in FIG. 1, the ratio of the second cross-sectional area to the first cross-sectional area is at most 0.7. In a further embodiment, not shown, the ratio of the second cross-sectional area to the first cross-sectional area is at most 0.5.

[0060] The conical transition region 44 of the clip 10 is formed exclusively by reshaping, and in particular exclusively by rotary swaging. The biasing element 52 is also formed exclusively by reshaping, and in particular exclusively by rotary swaging.

[0061] Neither the conical transition region 44 nor the biasing element 52 are polished.

[0062] A method for manufacturing the medical clip 10 is described below.

[0063] The medical clip 10 is formed by forming, or rotary swaging, the blank 56. This can be accomplished using known plunge (pierce) and in-feed rotary swaging processes.

[0064] The blank 56 is wire-like, i.e., in the shape of an elongated piece of wire, and defines a first circular cross-section 64 having a first diameter 58. The blank 56 is reshaped to form two undeformed end portions 66 and an intermediate portion 68 extending between the end portions 66. The intermediate portion 68 defines a second cross-section having a second diameter 60.

[0065] The conical transition region 44 is formed by the rotary swaging process between the undeformed end portion 66 and the intermediate portion 68. The cone angle 62 defined by the conical transition region is at least 10°.

[0066] After forming the intermediate portion 68 by the rotary swaging process, a portion of each end portion 66 is reshaped onto one of the clamp arms 14, 16, i.e., the clamp arms 14, 16 extend from the free ends of the two end portions 66. The free ends 18, 20 are therefore the free ends of the two end portions 66.

[0067] In the next step, the intermediate portion 68 is wound to form at least one complete winding to form the biasing element 52, i.e., the coil spring 54.

[0068] In a next step, the two end portions 66 that have not been reshaped into clamping arms 14, 16 are reshaped into a corresponding one of the connecting portions 34, 36. Each connecting portion 34, 36 connects one of the clamping arms 14, 16 to one of the ends 48, 50 of the biasing element 52 and is configured such that in the home position of the clip 10, the clamping arms 14, 16 are maximally close to each other and can be moved away from each other against the action of the biasing element 52 from the home position to an open position. This step can then also form the box lock 42 shown by way of example in FIG. 1 in the illustrated embodiment.

[0069] In the manufacture of clip 10, to form intermediate portion 68, blank 56 is reshaped using one or more reshaping tools 70, or reshaped using a reshaping machine 72, shown diagrammatically in Figures 2 to 5, with three reshaping tools 70 included with reshaping machine 72. In alternative embodiments, reshaping machine 72 may include two, four or five, particularly identical, reshaping tools 70.

[0070] In the manufacture of the clip 10, the conical transition region 44 has an unpolished configuration. This means that no grinding or other reworking is performed after reshaping by the rotary swaging process. Grinding or other reworking is not necessary when using the reshaping tool 70, which is described in more detail below, as opposed to the reshaping tools known from the prior art. Thus, both the conical transition region 44 and the intermediate portion 68 can be formed exclusively by reshaping, i.e. exclusively by rotary swaging.

[0071] To avoid the formation of flash in areas between adjacent reshaping tools 70 as they are pressed into blank 56, the reshaping tools 70 are rotated relative to blank 56 about a longitudinal direction 74 defined by blank 56 when they are disengaged (i.e., not in contact with one another) during reshaping to form intermediate portion 68. The direction of rotation, assuming blank 56 is fixed, is indicated diagrammatically by arrow 76 in Figures 2 and 5.

[0072] The blank 56 is made from a biocompatible metal, such as instrument steel or titanium.

[0073] A reshaping tool 70 in the form of a swaging tool 78 is used to form the conical transition regions 44, 46 in the manner described above. The swaging tool can be used to reshape the wire blank 56 as described in an initial step, so that the previously machined workpiece can be used to form the medical clip 10 in a subsequent step.

[0074] 2-5 show a schematic representation of a first embodiment of a reshaping tool 70. The reshaping tool 70 comprises a base body 80 defining a longitudinal direction 82 extending parallel to or coincident with a longitudinal direction 74.

[0075] In the case of the reshaping tool 70 of FIGS. 2-5, a base body 80 is formed with two molding elements 84 inclined at an infeed angle 86 relative to a longitudinal direction 82 .

[0076] A special feature of the molding element 84, in comparison with the molding elements of the reshaping tools known from the prior art, is that it has an asymmetric configuration with respect to a central plane 88 of the base body 80 which contains the longitudinal direction 82. The exact shape will be explained in more detail below.

[0077] 2-5, the in-feed angle 86 is at least 10°. In other embodiments, it may be at least 15°, or at least 20°.

[0078] Additionally, a calibration area 90 is formed on the base body 80. The calibration area extends parallel to or defines the longitudinal direction 82. The calibration area 90 is asymmetric with respect to the central plane 88.

[0079] The moulding element 84 in particular serves to characterise the reshaping tool 70. In a cross section perpendicular to the longitudinal direction 82, the moulding element 84 has a curved section line 92, also called a boundary line. The section line 92 is shown diagrammatically in Fig. 5. The section line 92 has a first end 94 and a second end 96. The moulding element 84 is concavely curved in a direction towards the blank 56. The section line 92 is therefore also concavely curved.

[0080] The curvature of the cross-sectional line 92 has a maximum value at the first end 94. This means that the radius 98 of the molding element 84 has a minimum value at the first end 94. On the other hand, the curvature of the cross-sectional line 92 has a minimum value at the second end 96. Thus, the radius in the region of the second end 96 is at a maximum.

[0081] In the embodiment of Figures 2-5, the curvature of the section line 92 decreases from the first end 94, but is not completely continuous. Rather, the curvature of the section line 92 begins at the first end 94 and is constant throughout an osculation angle region 100 defined relative to the longitudinal direction 82. The osculation angle region 100 extends through a circumferential angle 102 relative to the longitudinal direction 82 that ranges from about 5° to about 90°. In the embodiment of Figures 2-5, the osculation angle 102 of the osculation angle region 100 is approximately 50°.

[0082] In the embodiment of the reshape tool 70 of Figures 2-5, the curvature of the section line 92 is constant from the forged angle region 100 to the second end 96. Thus, the radius 98 in this portion is greater than the radius 98 at the forged angle region 100.

[0083] The radius 98 in the area between the forged angle region 100 and the second end 96 can also be made infinitely large. In this case, the curvature of the portion between the forged angle region 100 and the second end is zero, i.e., a flat portion 104 of the molded element 84 is formed there. Such a reshaping tool 70 is shown in FIG.

[0084] 6 shows a schematic representation of a reshaping tool 70 corresponding in basic structure to the reshaping tool 70 of FIGS. 2-5. Here, the forging angle region 100 is thus formed by a hollow cylindrical wall in the calibration region 90 having a radius 98 corresponding to half the second diameter of the intermediate portion 68 and having an opening region 106 extending between the forging angle region 100 and the second end 96. The two radii 98 are different. Moreover, the forging angle region 100 and the opening region 106 transition from one to the other without a kink.

[0085] 7 illustrates diagrammatically a further embodiment of a reshaping tool 70, in which the curvature of the section line 92 decreases continuously from a first end 94 to a second end 96. Thus, the section line 92 can be described as an involute.

[0086] The reshaping tool 70 is further configured such that the curvature at the first end 94 of the section line 92 in the infeed area 112 increases toward the calibration area 90. In other words, this means that in a cross section of the reshaping tool 70 perpendicular to the longitudinal direction 82 starting from the ends 108, 110 of the base body 80 facing away from each other, the curvature at the first end 94 of each section line 92 increases in the direction toward the calibration area 90. The infeed area 112 is the area where the molding elements 84 surround the infeed angle 86 in the longitudinal direction 82. Such a configuration of the infeed areas 112 on both sides of the reshaping tool 70 allows the wire-like blank 56 to be reshaped between the end portions 66 to form the intermediate portion in the manner described above.

[0087] The novel design of the reshaping tool 70 described above makes it possible to avoid drawbacks known from the prior art, one of which is that, in particular, the cross-sectionally symmetrical forming elements (also called dies) significantly limit the achievable radial movement of the reshaping tool 70 and the settable infeed angle.

[0088] The special asymmetrically designed contour of the molding element 84 prevents the formation of flash in both the intermediate portion and the conical transition region 44 since the cross-sectional line 92 perpendicular to the longitudinal direction 82 does not have symmetry between the ends 94, 96.

[0089] The construction of the reshaping tool 70 takes into account the relative rotational movement between the blank 56 and the reshaping tool 70 during the rotary swaging process. Due to the special shape of the molding element 84, the molding element 70 is open in such a way that as the rate of deformation increases, i.e. as the amount of material being deformed increases, in the area of ​​the material flowing into the open area 106 due to the above-mentioned rotational movement between the blank 56 and the reshaping tool 70, the tool edge of the reshaping tool 70, i.e. the tool edge defined by the second end 96 of the section line 92, is prevented from penetrating into the blank 56. For example, if the contour of the molding element 84 is flat on one side or has a defined larger radius, a forging angle area with a constant radius (i.e. one radius) with high compatibility is used, which constant radius serves to determine the radius of the finished rotary swaged workpiece.

[0090] The asymmetric shape of the proposed reshaping tool 70 allows a larger deformation rate and a larger infeed angle 86 to be obtained compared to the prior art. Furthermore, the asymmetric shape of the shaping element 84 allows forging with a value close to 1, since the formation of wings or polygons caused by the reshaping tools known from the prior art is prevented. This means that the radius of the workpiece, especially the intermediate portion 68, and the radius of the section line 92 in the forging angle region 100 or near the first end 94 are identical.

[0091] Workpieces rotary swaged using the asymmetric reshaping tool 70 can be identified by their geometric and microstructural characteristics. Workpieces produced in this way have deformation or reduction ratios and infeed angles that exceed the limits known from the prior art.

[0092] According to the method described above, the blank 56 can be rotary swaged in a first step to form two end portions 66 and an intermediate portion 68 therebetween. The conical transition region 44 and intermediate portion 68 formed with the proposed reshaping tool 70 do not require reworking and have high quality surfaces without burrs or polygonal formations. [Explanation of symbols]

[0093] 10 Medical Clips 12 Aneurysm Clip 14 Clamp arm 16 Clamp arm 18 Free end 20 free end 22 Clamping surface 24 Clamping surface 26 Clamp surface plane 28 Clamping surface plane 30 Proximal end 32 Proximal end 34 Connecting part 36 Connecting part 38 Connecting Elements 40 Connected Elements 42 Box Rock 44 Conical Transition Region 46 Conical Transition Region 48 End 50 End 52 Bias Element 54 Coil spring 56 Blank 58 First Diameter 60 Second Diameter 62 Cone angle 64 First Section 66 End part 68 Middle part 70 Reshaping tool 72 Reshaping machine 74 Longitudinal 76 angle 78 Swaging Tool 80 Base body 82 Longitudinal 84 Molding elements 86 Infeed angle 88 Central plane 90 Calibration Area 92 Section line 94 First end 96 Second End 98 radius 100 forging angle area 102 Circular Angle 104 Flat area 106 Opening area 108 End 110 End 112 Infeed Area

Claims

1. A medical clip (10), in particular in the form of an aneurysm clip (12), comprising: two cooperating clamp arms (14, 16); a biasing element (54) having two ends; Each of the two clamp arms (14, 16) is connected to one end of the biasing element (52) via a connecting portion (34, 36); In a basic position of the medical clip (10), the two clamping arms (14, 16) are maximally close to each other, in particular abutting each other, and are movable away from each other against the action of the biasing element (52) from the basic position to an open position, the two connecting portions (34, 36) defining a first circular cross-section (64) having a first diameter (58), the biasing element (52) defining a second circular cross-section having a second diameter (60), the second diameter (60) being smaller than the first diameter (58); the connecting portions (34, 36) taper toward the biasing element (52) such that a conical transition region (44, 46) is formed, the conical transition region (44, 46) defining a cone angle (62), the cone angle (62) having a value of at least 10 degrees.

2. a) said cone angle (62) has a value of at least 15°, in particular at least 20°, and / or 2. The medical clip of claim 1, wherein the first circular cross-section (64) defines a first cross-sectional area and the second circular cross-section defines a second cross-sectional area, the ratio of the second cross-sectional area to the first cross-sectional area being at most 0.7, in particular at most 0.

5.

3. a) said conical transition area (44) is produced exclusively by reshaping, in particular by rotary swaging, and / or b) said biasing element (52) is manufactured exclusively by remolding, in particular by rotary swaging; and / or c) said conical transition region (44) is not polished; and / or d) said biasing element (52) is unpolished; and / or e) the medical clip (10) is constructed integrally, in particular monolithically, and / or 3. The medical clip of claim 1 or 2, wherein: f) the biasing element (52) is configured in the form of a coil spring (54) having at least one complete winding.

4. 3. The medical clip of claim 1, wherein the clamping surfaces (22, 24) of the clamping arms (14, 16) define clamping surface planes (26, 28), the clamping surface planes (26, 28) being oriented parallel to one another in the basic position.

5. A reshaping tool (70), in particular a swaging tool (78), for reshaping a wire blank (56), in particular for forming a medical clip (10), comprising: The reshaping tool (70) comprises a base body (80) defining a longitudinal direction (82); At least one molding element (84) is formed on the base body (80) and extends at an infeed angle (86) relative to the longitudinal direction (82); At least one of the molding elements (84) has an asymmetric configuration with respect to a central plane (88) of the base body (80) that includes the longitudinal direction (82); In particular, said infeed angle (86) has a value of at least 10°, in particular at least 15°, more in particular at least 20°.

6. A calibration area (90) formed on the base body (80), the calibration area (90) extends parallel to or defines the longitudinal direction (82); 6. The reshaping tool of claim 5, wherein in particular the calibration area (90) has an asymmetric configuration relative to the central plane (88).

7. the molding element (84), in a cross section perpendicular to the longitudinal direction (82), defines a curved cross-sectional line (92) having a first end (94) and a second end (96); the curvature of the cross-section line (92) has a maximum value at the first end (94) and a minimum value at the second end (96); especially, a) the curvature of said cross-section line (92) is zero at said second end (96); and / or 7. A reshaping tool according to claim 5 or 6, wherein b) the curvature of the section line (92) decreases continuously from the first end (94) towards the second end (96).

8. the curvature of the cross-section line (92) is constant throughout a forged angular region (100) defined relative to the longitudinal direction (82) beginning at the first end (94); 8. The reshaping tool of claim 7, wherein the curvature of the section line (92) between the forged angular region (100) and the second end (96) is less than the curvature of the section line (92) at the forged angular region (100).

9. The curvature of the section line (92) starting from the forged angle area (100) is: a) decreasing, in particular continuously, towards said second end (96); and / or 9. The reshaping tool of claim 8, wherein b) the curvature of the cross-section line (92) is constant up to the second end (96), in particular the curvature of the cross-section line (92) is zero (96) from the forging angle region (100) to the second end.

10. 9. The reshaping tool according to claim 8, wherein the forging angle region (100) extends over a circumferential angle (102) in the range of about 5° to about 90°, in particular in the range of about 10° to about 50°, relative to the longitudinal direction (82).

11. 8. The reshaping tool according to claim 7, wherein the curvature of the section line (92) of the infeed area (112) at the first end (94) increases, in particular continuously, in the direction of the calibration area (90).

12. A reshaping machine (72), in particular a rotary swaging machine, comprising at least one reshaping tool (70) according to claim 5.

13. A method for manufacturing a medical clip (10), particularly a medical clip (10) in the form of an aneurysm clip (12), comprising: the method comprising reshaping, in particular by rotary swaging, a wire blank (56) having a first circular cross section (64) and a first diameter (58); said reshaping forming an intermediate portion (68) having a second circular cross section and a second diameter (60) between the two undeformed end portions (66) of said blank (56); said reshaping forming at least one conical transition region (44, 46) between said undeformed end portion (66) and said intermediate portion (68); At least one of the conical transition regions (44, 46) is configured to have a cone angle (62) of at least 10 degrees.

14. a) the intermediate portion (68) is wound to form at least one complete turn of wire to form the biasing element (52); and / or b) reforming a first portion of each of the two end portions (66) into a clamping arm (14, 16), the clamping arm extending from the free ends (18, 20) of the two end portions (66); 14. The method according to claim 13, wherein the second portion of each of the two end portions is formed into a connecting portion, each connecting portion connecting the clamping arm to one end of the biasing element, such that in a basic position of the medical clip, the clamping arms are maximally close to each other, in particular abutting each other, and are movable away from each other against the action of the biasing element from the basic position to an open position.

15. reshaping the blank (56) with a reshaping tool (70) according to claim 5 to form the intermediate portion (68); 15. The method of claim 13 or 14, wherein, in particular, during reshaping to form the intermediate portion (68), the blank (56) and at least one reshaping tool (70) are rotated relative to one another about a longitudinal direction (74) defined by the blank when they are out of engagement.

16. 15. The method of claim 13 or 14, wherein the blank (56) is reshaped to form the intermediate portion in a reshaping machine (72) as defined in claim 12.

17. a) forming at least one of said conical transition regions (44) without grinding, and / or 15. The method according to claim 13 or 14, wherein b) at least one said conical transition region (44) is formed exclusively by reshaping, in particular exclusively by rotary swaging.

18. Use of the method according to claim 13 or 14 for manufacturing a medical clip (10) according to claim 1 or 2.

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