WO2023041517A1

WO2023041517A1 - Key or key blank, production method and lock system

Info

Publication number: WO2023041517A1
Application number: PCT/EP2022/075383
Authority: WO
Inventors: Benjamin Gugerli; Markus Kornhofer; Christian Raimann
Original assignee: Dormakaba Austria Gmbh
Priority date: 2021-09-14
Filing date: 2022-09-13
Publication date: 2023-03-23
Also published as: CH718959A1

Abstract

The key or key blank (2) has a ramp face (24) at the front. Said ramp face extends over more than half the key thickness, i.e., the ramp face projects from one of the flat sides, through the centre plane between the flat sides, to a front protrusion. The key or key blank has a particular contour at the front. In a projection perpendicular to the flat sides, the contour forms a central, straight first section at the front and a second, at least partially curved section towards one side, said second section extending as far as the narrow side and merging into same. This second section is set back relative to a uniform curve line. This shape of the contour means that the space for coding bores on the key is optimised, while at the same time it is ensured that the key does not have any sharp edges at the front.

Description

KEY OR BLANK KEY, MANUFACTURING PROCESS AND LOCKING SYSTEM

The invention relates to a key element, namely a mechanical key or key blank, a method for producing such a key element, and a locking system with a lock cylinder and key element.

Lock cylinders have a stator non-rotatably attachable to a lock (sometime called "cylinder housing") and a rotor (sometime called "cylinder core") rotatable about the axis of the lock cylinder upon insertion of a matching key. The turning of the rotor moves output means, which are used to actuate a bolt or other means related to the desired function of the lock cylinder.

Many mechanical locking cylinders for reversible flat keys or for other flat keys have tumbler-counter-tumbler pairs that interrogate the mechanical coding of the key. The mechanical codings are designed as bores with different depths depending on the coding, in particular on the flat side of the key. The number of possible guard locking lengths, together with the number of bores, determines the number of possible permutations, which should be as large as possible.

In the case of flat keys with coding indentations (coding bores, coding grooves) on at least one flat side (key surface), the following situation arises: The difference between different pin lengths (lengths of tumblers) cannot be arbitrarily small, so that if the coding does not match gives a clear blockage. Ultimately, therefore, the maximum depth of coding depressions in the key determines this number of possible tumbler lengths. For this reason it is already known that coding indentations can be so deep that they penetrate a midplane of the key shank, ie they are deeper than half the thickness of the key shank. Such keying depressions, particularly keying wells, are sometimes called "paracentric". In order for a lock cylinder with paracentric pins to work, it must be ensured that the pins protruding beyond the central plane of the key shank - and thus also the corresponding key channel in the lock cylinder - cannot block the key from being inserted into the key channel. Depending on the configuration of the radially inner pin ends, it can be provided for this purpose that a ramp surface must be provided at the front end of the key, i.e. the key tip, for example by the key being rounded towards the tip or designed to taper flat towards the front.

In the field of locking systems, the manufacturer of the locking system will usually deliver key blanks to specialist departments ex works. The key blanks have, for example, locking system-specific security features and, in some cases, coding that is individualized for the relevant department, for example in the form of a profile. The specialist department will then create customized keys for its customers by adding coding holes to the key blanks. The security features already on the key blank, which differ from mere coding holes, are generally particularly advantageous, since they are less easily copied by unauthorized key copiers than coding holes in the flat side of the key, thus ensuring that only authorized bodies supplied with blanks by the manufacturer can produce keys . The shape of the key tip is such a security feature that is already present on the key blank and therefore cannot be copied with key-cutting machines. However, a ramp surface on the tip of the key can make the production of mechanical flat keys more expensive because, in addition to punching out the outer contour and milling in grooves as a profile, it requires additional, more complex processing steps. In addition, it can result in a sharp edge being formed at the tip of the key, which can be detrimental both in terms of ease of use and in terms of wear and tear over the years.

It is therefore an object of the present invention to provide a key element (key blank or key) which overcomes disadvantages of the prior art and in particular has a ramp surface on the key tip which is relatively easy to manufacture and which is wear-resistant and user-friendly is as beneficial as possible.

This object is solved by the invention as defined in the claims

The invention relates to a key element (key or key blank) with a key bow and a key shaft extending along a key axis from the key bow to a front key tip with two parallel flat sides and two opposite narrow sides. On the side of the key tip, ie on the front, the key shank has a run-on surface. This extends over more than half the thickness of the key, i.e. at least one lateral position (in particular corresponding to the position at which the main row of pins is arranged in the locking system) the ramp surface protrudes from one of the flat sides through the central plane between the flat sides to a front side Attachment at the tip of the key or to the side of it on the front of the key. The run-on surface can extend from the front end of the key, which forms the contour, to a transition into the flat side. Due to the fact that it reaches at least partially below a central plane of the key shank on the front side, pins with a smaller diameter and/or with only slightly rounded radial inner end that reach particularly far into the key channel cannot block insertion of the key.

In this text, the term "key tip" refers to the front end of the key or key blank. The term makes no statement about the shape of the front end, i.e. it does not have to be pointed in particular.

The key element has a special contour on the front. In a projection perpendicular to the flat sides, the contour first and foremost forms a central, straight first section and, towards one side, a second, at least partially curved section that runs to the narrow side and merges into it. This second section is set back from an arcuate line, which arcuate line is defined as having a constant radius and having a tangent coinciding with the first section at a transition to the first section and a tangent coinciding with the narrow side at a transition to the narrow side .

The curved line is a hypothetical, imaginary curved line, ie the contour of the key does not have this curved line, but is offset to the rear in relation to it. The key element can in particular be a reversible key blank or a reversible key, ie at least the key shank is then symmetrical with respect to a rotation of the key element by 180° about the key axis.

The contour will be symmetrical, especially when the key element is a reversible key element. If there is symmetry, there is a second section of the type defined above on both sides. All statements made in this text about the shape of the contour are to be understood in such a way that they also apply in particular to correspondingly symmetrical contours, and all statements in this text about the shape of the Key elements apply in particular to reversible key elements, i.e. key elements whose shank is symmetrical with respect to a rotation of 180° around the key axis. The key bow can also have this symmetry, but this is not necessary for the function.

This contour with a combination of a straight section at the front with a lateral section that is curved at least in some areas but is set back compared to a curved line of the type mentioned has proven to be advantageous. First, the front straight section allows a range of keyings to be maximized near the key axis - i.e. near the center both in terms of space on the key and possible depth of keying holes (keyword 'paracentricity'). Secondly, the shape with the section that is curved at least in certain areas is well suited for the efficient production of a stamped blank by means of stamping. Third, setting the contour back from the arc line mentioned ensures the following: Even if the ramp is flat (which can be advantageous from a manufacturing point of view, see comments below) and is relatively steep (which saves valuable space on the key), there is no sharp one at the front edge. Such would result if the contour were not would be set back. Fourth, the shape is otherwise free of sharp edges or corners.

The run-on surface can in particular be flat and/or it can be inclined in two directions in particular relative to the normal to the flat side, i.e. a normal to the run-on surface is inclined both forwards and to the side in relation to the normal to the flat side. This condition applies, for example, at least to the positions with that distance (y-position) from the vertical plane through the key axis (vertical center plane) in which the pins of the main row of pins touch the ramp surface when the key is inserted. This has the effect that the pins at their radially inner end acentrically, i.e. not in the middle in relation to their pin axis, but on a flank hit the run-on surface. The first consequence of this is that the pin is pushed slightly to the side, i.e. in the y-direction, which is why it is guided to a better defined position compared to the prior art, even if there is a small amount of play. Second, it means that the tip (the radially inner end) of each pin does not drag across the ramp. Rather, if the pin tapers radially inward or is rounded, the pin will rest laterally against the ramp surface and can at least partially roll off it, i.e. insertion of the key can cause rotation of the pin about its pin axis. This reduces the mechanical resistance when inserting the key. In addition, the wear on the pin is better distributed compared to the prior art.

The y-position of the main row of pins (e.g. main row of tumblers) is defined by the lock cylinder, but also on the key element. If the key element is a key, this y-position can be easily determined: it corresponds to the position of the row of coding holes or, if there are several such rows, the row with the most and/or deepest coding holes (main row). Is this If the key element is a key blank without the coding holes, the y position of the main row of pins can be determined according to the y position of the main row of coding holes in embodiments as follows: Starting from the vertical plane through the key axis, a reversible key shows through the ramp surface on which side of this vertical plane is the main row. If the key blank is profiled (i.e. not rectangular in cross-section perpendicular to the key axis but rather has ribs and grooves parallel to the key axis) then the y-position of the main row of pins may correspond to the y-position of the rib on the corresponding side closest to the vertical plane through the key axis.

The second section may have multiple subsections. For example, a first subsection with a first radius of curvature Ri can be present, as well as at least one further subsection that has a second radius of curvature R2 that is larger than Ri, or that is straight. The first sub-section connects to the first section on the front.

The radius of curvature Ri of the first sub-section can in particular be smaller than the width b of the area of the key shank between the first section and the narrow side.

At the transition to the first section, the second section can have a tangent that coincides with the latter, ie at this transition the contour can be continuously differentiable, thought of as a function, ie it can be “kink-free”. In addition or as an alternative, the transition between the second section and the narrow side can also be “kink-free”, ie the tangent to the second section at the transition to the narrow side can coincide with the narrow side.

In particular, the second section can have the first subsection with the first radius of curvature Ri, a second, straight subsection and a third subsection with the larger radius of curvature R2 in this order from the first section to the narrow side. In an otherwise identical constellation, the second subsection can also be curved instead of straight, with a radius of curvature that is greater than the radii of curvature of the first and third subsections.

As already mentioned, there is no sharp edge at the front due to the fact that the contour is set back in relation to the above-mentioned curved line. A preferred feature of the present invention is that instead a front face is defined which is perpendicular to the flat sides and forms a front end of the key shank, the front face merging at both ends into the narrow sides parallel to the key axis.

The front surface thus runs from one narrow side with the contour according to the definition according to the invention to the other narrow side. The front face may be continuous or may be broken by grooves running parallel to the key axis to the front end.

At its narrowest point, the front surface can be at least 0.05 mm, preferably at least 0.08 mm, in particular at least 0.12 mm high. The maximum height at its narrowest point can be 0.5 mm or 0.3 mm, for example. The height in this text denotes the extension perpendicular to the flat sides; according to the coordinate system used here, i.e. the expansion in the z-direction.

If the front surface is interrupted, a narrowest point may not be defined. The following generalized condition therefore applies accordingly: the transition between the ramp surface on the one hand and the front surface on the other hand has a distance in the z-direction (direction perpendicular to the flat sides) from the flat side opposite the ramp surface of at least 0.05 mm, preferably at least 0.08 mm, in particular at least 0.12mm. The maximum distance at the point where the transition comes closest to the opposite flat side can be 0.8 mm, preferably 0.6 mm, particularly preferably 0.4 mm).

Both conditions (the condition for the case of an uninterrupted front surface as well as the generalized condition, which also applies to interrupted front surfaces) state that no sharp edge can form between the ramp surface on the one hand and the opposite flat side on the other hand, but that on every position along the width (every y-position) there is a distance between the ramp surface and the opposite flat side. This distance is defined by the front surface or, if present, by a groove that interrupts this and extends to the front end.

In some areas it can be provided that the ramp surface merges into the front surface and the front surface forms an upper or lower edge ("top" or "bottom" are to be understood in relation to the z-direction) of the key shank and/or directly in the flat side goes over. In other words, in one latitude (at a y-position) the key tip is one-sided by not being to both Flat sides towards ramp surfaces are available, but only to a flat side, while the front surface is immediately adjacent to the other flat side and merges into it.

In a width section behind which a row of coding bores is provided on the (finished key) in the x-direction - i.e. at the y-position of a row of coding bores, in particular at the y-position of the centers of the coding bores - the ramp surface can be inserted into the front Go over surface and the front surface form an upper or lower edge of the key shank and / or go directly into the flat side.

The front face may include an end face at the wrench tip having parallel edges sloping to the planes defined by the flats 21 (and correspondingly to the median plane 19 which is parallel thereto). The parallel edges can in particular have a distance of at least 0.5 mm, in particular at least 0.7 mm. A maximum distance can be 1.5 mm or 1.2 mm, for example.

Instead of a rounded or pointed structure, as is known from the prior art, a key element of the type described here can therefore have an end face at the very front, which is preferably perpendicular to the key axis. The shape of the end face may be that of a rhomboid, with long sides oblique to the median plane and short sides perpendicular to the median plane.

An end surface on the tip of the key can lie at least between two width sections, behind which the centers of the coding bores are provided in the x-direction. Laterally to the end surface, the front surface may comprise a (continuous or discontinuous) transition surface. In at least one width section (in the region of the transition surface), a first edge of the front surface can be designed as a transition into the flat side and the second edge can run in an arc. The transition surface can, for example, connect to the end surface. In particular, an uninterrupted or interrupted transition surface can be provided on both sides of the end surface. The transition surface connects to the end surface towards the middle and to the corresponding side towards the side, but like the end surface it is also perpendicular to the central plane (and correspondingly to the flat sides).

In a plan view of the front surface in the direction of the key tip, the front surface can include a first curved edge and a second curved edge,

• wherein the first and second edges are offset widthwise; and or

• where the first and second edges include a local extreme point.

If the key element is a reversible key element, the ramp surface - more precisely: the two symmetrically arranged Auf! surfaces - be arranged in such a way that they are created by removing material using a milling tool with a concave V-shaped milling profile, which is guided diagonally over the tip of the wrench, i.e. in a direction of movement perpendicular to the wrench axis and at an angle different from 0° to the wrench horizontal midplane.

The milling tool can be recognized in such a way that there is no sharp edge on the front side of the key, but an end face whose width - perpendicular to the Direction of movement of the milling tool - results from the distance of the rotary axis from the tip of the key during the milling processing step.

The key element can be a key, namely a flat key, in particular a reversible key. This has at least the main row of coding bores--other coding bores may be present in addition to the main row. Alternatively, the key element can also be a key blank, in which case a profiling can already be present on the key blank in addition to the ramp surface.

The invention also relates to a locking system which, in addition to a key element, also has a lock cylinder matched to this. In a manner known per se, such a lock cylinder has a lock cylinder stator and a lock cylinder rotor with a key channel into which the key shank can be inserted. Coding bores on the key element - if this is a finished key, otherwise as soon as they are attached - can be scanned by pins in the lock cylinder. The pins in the lock cylinder can in particular be tumblers in the lock cylinder rotor, which interact with counter tumblers in the lock cylinder stator and only enable rotation of the lock cylinder rotor if the depth of the coding bores fits. The pins of at least the main row (ie the row whose position corresponds to the main row of coding holes; in reversible key systems these will be distributed over the corresponding rows on either side of the key) are raised by the ramp surface when the key is inserted . In this case, the pins hit the run-on surface in particular acentrically, which is why they can at least partially roll on it when they are pushed in and do not necessarily grind over it. Instead of tumblers or in particular in addition thereto, the lock cylinder can also have other pins that scan the coding of the key, in particular profile pins or profile wobble pins.

The invention also relates to a method for producing a key element using the principle described above, according to which a preliminary product, optionally before or after the production of the profiling, by means of a milled profile in a single step with the two also described, necessary for a reversible key system, mutually symmetrical ramp surfaces is provided.

In this text, "coding hole" refers to a recess in the key, the dimension of which is chosen based on a desired coding. Coding holes can be created by drilling; however, corresponding indentations produced using other methods are also referred to here as "coding bores".

In this text, the orientation designations "radial", "radial -internal", "axial" etc. generally, unless otherwise taught, refer to the key axis, which in the locking system also corresponds to the locking cylinder axis when the key is inserted. "Front" refers to the position towards the tip of the key, and "back" is a position towards the bow of the key.

The subject of the invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings. In the drawings, the same reference numbers indicate the same or analogous elements. Show it:

1 is a perspective view of a key; Figure 2 is a corresponding view of a key blank for making a key of Figure 1;

3 shows a sectional view of a section of a lock cylinder when a key is inserted;

FIG. 4 shows a view of the foremost area of the key blank according to FIG. 2;

FIG. 5 shows a view of the key blank according to FIG. 2 from the front; FIG.

6 shows a schematic representation of a milling tool;

FIG. 7 shows a view of the key blank according to FIG. 2 from a direction which corresponds to the direction of movement of the milling tool when creating the ramp surfaces;

8 shows a representation of the contour of the foremost area of the key or key blank; and

9 is a view of another key blank.

Figure 1 shows an example of a key 1 with a key bow 11 and a key shank 12. The key 1 is a flat key in which the key shank is essentially non-square in cross section perpendicular to a key axis 10, resulting in two parallel flat sides 21 and two narrow sides 22 with a smaller area than the flat sides 21 are defined. An edge 25 is formed between the flat sides 21 and the narrow sides 22 . Fig. 1 also shows the Cartesian coordinate system used in this text, with the x-direction running parallel to the key axis and the z-direction perpendicular to the flat sides 21.

At least one row of coding bores 31 running parallel to the key axis 10 is present on the key shank 12 .

In addition to the coding bores, the key in the illustrated embodiment also has a profile in the form of grooves 32 running parallel to the key axis. For example, basic profile grooves (which are always the same in the locking system and only exclude keys from other locking systems) and/or variation profile grooves (which form a code) can be present. Corresponding ribs 33 result between the grooves 32.

The key shown is a reversible key, i.e. the key shank is symmetrical with respect to a rotation of 180° about the key axis 10, and the codes on the front and rear flat side 21 are correspondingly identical.

In contrast to the illustrated embodiment, the key can also have a different number of rows of coding holes on the flat sides, e.g. 1, 3, 4, 5 or 6, instead of or in addition to the profiling, and/or it can also have coding holes on the narrow sides 22 have.

In the exemplary embodiment shown, the key also has a plurality of coding recesses 35 which are formed as cuts along the edge 25 . FIG. 2 shows the key blank from which the key is made by attaching the individual coding bores 31 and optionally coding recesses 35 .

Toward the key tip 23, the key has a ramp surface 24 sloping forwards, which allows the lock cylinder to have pins (e.g. tumblers) scanning the coding bores, which protrude further into the key channel than up to the central plane. This principle is illustrated in FIG. 3, which shows a schematic section through a lock cylinder 40 with a lock cylinder rotor 43 that can rotate in the lock cylinder stator 44 and has a key channel 45 . The locking cylinder rotor has a plurality of rotor pin bores, each with a pin that forms a tumbler 46, the length of which depends on the coding. Corresponding spring-loaded counter-tumblers 47 are arranged in stator pin bores, which are aligned with the rotor pin bores in a basic position of the rotor, with the lengths of the tumblers 46 and counter-tumblers 47 of each tumbler-counter-tumbler pin pair being able to add up to the same total length in each case. In a manner known per se, a suitably coded key can align the boundary surface between tumblers and counter tumblers with the shearing surface between rotor and stator and thus make it possible for the rotor to rotate away relative to the stator around the lock cylinder axis, which corresponds to key axis 10 when the key is inserted .

As shown in particular in FIG. 4, the run-on surface is essentially flat. In addition, it not only slopes forwards towards the key tip 23 in the manner of a ramp, but also inclines radially outwards. In other words, the normal N to the ramp surface (e.g. at least at that y-position which corresponds to the y-position of the row of coding bores 31 or at least one of the rows of coding bores) forms both an angle (a) to the xy-plane (the level parallel to the flat sides) and an angle (ß) to the xz plane (ie that plane which is parallel to the key axis 10 but perpendicular to the flat sides 21).

Due to this inclination towards the x-z plane, the ramp surface 24 not only causes longer pins protruding into the key channel to be lifted reliably and optionally against a spring force and pushed radially outwards. Rather, it also causes the pins at their radially inner end not to hit the run-on surface centrally (i.e. in the middle in relation to their pin axis), but rather on a flank. The first consequence of this is that the pin is pushed slightly to the side, i.e. in the y-direction, which is why it is guided to a better defined position compared to the prior art, even if there is a small amount of play. Secondly, it means that the tip (the radially inner end) of the pin does not drag over the ramp surface. Rather, the pin, if it runs radially inward, as shown in FIG.

The run-up surface 24 is of particular importance at the position at which the pins of the main row of tumblers run up when the key is inserted. In the case of the key and key blank shown, this corresponds to the position of the first rib 34 seen from the center (d. from the vertical center plane, ie the xz plane through the key axis), see FIG y position substantially below the horizontal center plane 19 (the xy plane through the key axis), which can be seen particularly well in FIG. FIG. 5 shows a view of the key blank 2 from the front, ie from the tip 23 of the key. P is the position of the main row of tumblers—corresponding to the position of the coding bores 31 of the main row, see FIG. 1. Another advantage of the key and key blank according to the invention is that the key blank 2 and thus also the key 1 are easier to produce than the prior art from a punched-out preliminary product (punched blank) before or after the profiling has been applied in a single work step. They can be created by a milling tool 51 with a concave V-milling profile (shown schematically in FIG. 6, with axis of rotation 52 and erosive part 53; opening angle of the V-profile: 5), which is at an angle 8 different from 0° to the xy -plane runs across the tip of the key at such a distance that an area of width d remains on the front side. The movement takes place perpendicular to the main axis (axis of rotation 52) of the milling tool, ie the angle θ is the angle between the xy plane and the plane perpendicular to the axis of rotation 52 of the milling tool during the milling process. FIG. 7 shows the corresponding milling cutter contour on the key blank.

Correspondingly, the axis of rotation 52 of the milling tool is set at an angle θ to the vertical (to the z-axis) during the milling machining step.

In the illustrated embodiment, 6=70° and 8=35° and d=0.8mm; this selection of the machining angles 5 and s also defines the angles a and ß. Overall, it is preferred if 55°<6<90° and 25°<s<45°.

In Fig. 5 one can also see that the milling profile is applied in such a way that a strip with a width d (measured perpendicular to the direction of movement) remains at the tip of the wrench. Therefore, there is no sharp edge at the tip of the key, but rather an end surface 26. The width d results from the correspondingly selected milling profile in the illustrated milling profile From was the axis of rotation 52 of the key tip 23 during the milling processing step.

As can also be seen clearly in FIG. 5, the end surface 26 comprises edges which run obliquely to the central plane 19 (perpendicular to the plane of the drawing in FIG. 5) and are parallel to one another, so that the end surface 26 has the shape of a rhomboid.

FIG. 8 shows the outer contour 60 of the preliminary product from which the key blank is made in the area of the foremost part of the key shank 12, i.e. in the area of the key tip, viewed from the flat side, i.e. in a projection onto the x-y plane. The outer contour 60 is not changed, at least not significantly, by the milling of the ramp surfaces 24, the application of the profile with the grooves 32 and also by the application of the coding bores and possibly coding depressions, so that the outer contour 60 also corresponds to the outer contour of the bowl blank 2 and the key corresponds to 1.

Since the key 1 is a reversible key, the requirement also applies to the outer contour 60 that it is symmetrical with respect to the key axis 10, i.e. (as a two-dimensional contour) with respect to a central axis. Tip of the key (the foremost point on the key axis 10), the contour has a straight first section (central section) 61, which is perpendicular to the key axis, and a second section 62, which from the straight first section 61 to the narrow side 22 runs and which is at least partially curved.

In the illustrated embodiment, it can also be seen that the second section 62 has three distinguishable sub-sections, namely a first, curved sub-section 63 with a first radius of curvature from the inside outwards Ri, a second straight subsection 64, and a third curved subsection 65 having a second radius of curvature R2 which is greater than the first radius of curvature. The dashed lines in FIG. 8 show an imaginary division between a central area, which is delimited at the front by the straight first sections 61 on both sides, and the two side areas with width b, which are delimited at the front by the second section 62 .

Also shown in FIG. 8 is a hypothetical contour 69 that would result if there were only a single curved section starting from the straight first section (which is advantageous because it allows as much space as possible for the row with the essential coding bores). , whose radius Rb corresponds to the width b, which results from the condition that the tangents at the transitions to the first section 61 and to the narrow side 22 therefore coincide in parallel with the first section 61 and the narrow side 22 (i.e. perpendicular or parallel to the run along the key axis; the contour is intended as a function and can also be continuously differentiated at the transitions). It can be seen that the contour 62 is slightly set back with respect to this hypothetical contour 69, without changing the overall length of the key in the important central area.

This results in an important advantage: With the shape of the ramp surfaces explained with reference to FIGS. 5-7, the hypothetical contour 69 would have a sharp edge at the thinnest points on the front (correspond approximately to the area of the second subsection 64). Such is undesirable. Firstly because the sharp edge can damage trouser pockets or other textiles that come into contact with the key. Second, a sharp edge is also undesirable from the point of view of wear and tear over the years. The setting back of the contour in this area prevents such a sharp edge, which can be seen clearly, for example, in FIG. 4, where the front surface 27 of one of the thinnest (narrowest) points is clearly visible is. Even at its narrowest point, the front surface can be at least 0.05 mm, preferably at least 0.08 mm, in particular at least 0.12 mm high (expansion in the z-direction). In addition to the end surface 26, the front surface 27 also includes a transition surface 28 on the side thereof, which extends from the end surface 26 in an arc to one of the narrow sides 22 and merges into this. The front surface thus runs, for example, uninterruptedly from one narrow side to the other narrow side. The front surface 27 forms a front end of the key shank.

The resetting of the contour 60 compared to the hypothetical contour 69 results from the fact that the first subsection 63 has a smaller radius of curvature Ri than the width b and/or that the transition between the first area 61 and the second area forms a slight kink, i.e. that the tangent to the second area 62 at the transition to the first area 61 is not parallel to the first area 61 . In the example shown, at least the condition Ri<b is met. This condition in turn means that the second region, in addition to the first subsection 63 with the smaller radius of curvature, has at least one further subsection with a larger radius of curvature (third subsection 65) and/or a non-curved subsection (second subsection 64).

As can also be seen particularly well in FIGS. 4 and 5, the ramp surface 24 transitions into the front surface 27 in some areas. The front surface 28 merges directly into the corresponding flat side 21 on the upper or lower side in a width section (laterally; in particular at position P of the main coding row, particularly in the area of the transition surface 28), while on the opposite side, i.e. on the lower or upper side, merges into the ramp surface 24 in this width section. In this width section, the front surface thus forms an upper or lower edge of the key shank. One edge of each transition surface 28 (in the orientation of Fig. 5 the right edge of the transition surface 28 shown above and the left edge of the transition surface 28 shown below) represents a transition into the respective flat side, and the other edge runs, as can be seen in Fig 5 well sees, arcuate.

In the plan view according to FIG. 5, one can also see that the two edges which delimit the front surface 27 at the top and bottom of the key (that is, to the left and to the right in FIG. 5) have disappeared as a whole.

• wherein the first and second edges are offset in width (y-direction) from one another;

• where the first and second edges include a local extreme point.

FIG. 9 shows a perspective view of the key shank 12 of a variant of a blank for a reversible key. As in the other described embodiments, the features of the key shank described in the present text are designed in such a way that there is symmetry with respect to a rotation of 180° about the key axis.

The key blank of Figure 9 differs from the embodiments of Figures 4 and 5 in particular in that on each flat side one of the grooves 32 running parallel to the key axis all the way to the front is arranged in the flat side 21 in such a way that it covers the front surface 27 in the area of the transition surface 28 is interrupted, so that the transition surfaces 28 present on both sides of the end surface 26 are each divided into two sub-surfaces, between which the respective groove 32 lies. Therefore, no narrowest point of the front surface 27 and accordingly no minimum height is defined. Even in these embodiments, however, results Condition that no sharp edge can form on the front side between the ramp surface on the one hand and the opposite flat side on the other hand, and that the key blank (and accordingly the key made from it) is not rounded off at the front either, but that between the ramp surface 24 and the flat side 21 there is a Flat side vertical front surface is formed. The minimum distance a between the transition between the ramp surface and the front surface on the one hand and the plane of the opposite flat side (in Fig. 9 this is the lower flat side for the ramp surface 24 shown on the right, and the upper flat side 21 for the ramp surface 24 shown on the left) is always the same different from zero and is more than 0.05 mm, preferably at least 0.08 mm, in particular at least 0.12 mm.

Claims

- 24 - CLAIMS

1. Key el em ent (1, 2) with a rear key bow (11) and along a key axis (10) from the key bow (11) to a front key tip (23) extending key shank (12) with two mutually parallel flat sides (21) and two opposite narrow sides (22), the key shank (12) having a ramp surface (24) towards the key tip (23) which extends from one of the flat sides (21) through a central plane (19) between the flat sides to a front shoulder, characterized in that the key shank has a contour (60) on the front side in a projection perpendicular to the flat sides (21), which on the front side towards the key tip has a central, straight first section (61) and a has a second section (62) that is curved at least in some areas and runs from the first section (61) to one of the narrow sides (22), and that the second section (62) is set back towards the rear in relation to a curved line (69) running steadily from the first section (61) to the narrow side (22), the curved line (69) having a constant radius and at a transition to the first section a tangent coinciding with the first section and has a tangent that coincides with the narrow side at a transition to the narrow side.

2. Key element according to claim 1, wherein the second section (62) has a first subsection (63) adjoining the first section (61) with a first radius of curvature Ri and at least one further subsection (64, 65) which has a second radius of curvature R2 which is larger than the first radius of curvature Ri, or which is straight.

3. Key element according to claim 2, wherein the second section (62) has a straight second subsection (64) adjoining the first subsection (63) and a curved third subsection extending between the second subsection and the narrow side (22). (65).

The key element of claim 3, wherein the third subsection (65) has a radius of curvature R2 that is greater than the first radius of curvature Ri.

5. Key el ement according to any one of claims 2 to 4, wherein the first sub-section (63) has a constant radius and at a transition to the first section (61) has a tangent coinciding with the first section (61).

6. Key element according to one of the preceding claims, wherein the run-on surface (24) is flat and is inclined in two directions relative to the normal to the flat sides (21), in that a normal to the run-on surface (24) is positioned relative to the normal to the flat side in both directions inclined forward and to one side.

7. Key element according to one of the preceding claims, wherein the key shank (12) is symmetrical with respect to a rotation about the key axis (10) by 180°, whereby the key element is a reversible key element, and whereby the key element together with the ramp surface (24) has one to this symmetrical second ramp surface (24).

8. key el em ent according to claim 7 based on claim 6, wherein the

Ramp surface (24) and the second ramp surface (24) are designed and arranged in such a way that they are created by removing material using a milling tool (51) with a concave V-shaped milling profile, which is guided in one direction of movement over the key tip (23). which direction of movement is perpendicular to the key axis and at an angle (s) other than 0° to the flat sides.

9. A key element according to any one of the preceding claims which is flat at the key tip in that there is a front end face (26).

10. Key element according to one of the preceding claims, wherein the ramp surface runs through the center plane (19) at a position (P) of a main row of coding bores (31), and that at this position a normal to the ramp surface (24 ) is inclined both forward and to one side from the normal to the flat side.

11. Key element according to one of the preceding claims, wherein a front surface (27) is defined, which is perpendicular to the flat sides (21) and forms a front end of the key shank (12), the front surface (27) on both of them ends into the narrow sides (22) parallel to the key axis (10).

12. Key element according to claim 11, wherein a minimum distance (a) between the transition between the ramp surface (24) and the front surface (27) on the one hand one of the plane of the opposite flat side (21) - 27 - on the other hand is at least 0.05 mm, preferably at least 0.08 mm, particularly preferably at least 0.12 mm.

13. Key element according to Claim 11 or 12, it being provided in some areas that the ramp surface (24) merges into the front surface (27) and the front surface (27) forms an upper or lower edge of the key shank (12) in some areas and/or merges directly into the flat side (21).

14. Key element according to one of claims 11-13, wherein in a width section, behind which in the direction parallel to the key axis (10) the centers of a row of coding bores (31) are provided, the ramp surface (24) in the front surface (27) and the front surface (27) forms an upper or lower edge of the key shank and/or merges directly into the flat side (21).

15. Key element according to one of the preceding claims, having the key tip (23) towards an end surface (26) which is preferably perpendicular to the key axis (10).

16. Key element according to claim 15, wherein the end surface (26) comprises parallel edges running obliquely to the central plane (19), the edges having a distance (d) of at least 0.5 mm, preferably at least 0.7 mm, for example.

17. Key element according to claim 15 or 16 and any one of claims 11-14, wherein the front surface (27), the end surface (26) and at least one - 28 -

Transition surface (28), wherein a first edge of the front surface (27) is designed as a transition into the flat side (21) and a second edge is curved at least in some areas, with the transition surface (28) adjoining the end surface (26), a transition surface (28) being provided in particular on both sides of the end surface. Key element according to one of the preceding claims, which is designed as a key blank (2) with a profile, the profile comprising a plurality of grooves (32) and ribs (33, 34) formed between these. Key element according to one of Claims 1-17, which is designed as a key (1) with at least one main row of coding bores (31). Locking system, having a key element according to Claim 19, and a lock cylinder (40) with a lock cylinder stator (44) and a lock cylinder rotor (43) mounted in the lock cylinder stator (44) with a key channel, in which the key shank (12 ) of the key element can be inserted, the lock cylinder having at least one pin (46) which scans one of the coding bores (31) and enables or does not enable rotation of the lock cylinder rotor (43) depending on its presence and depth, the pin (46) is arranged in such a way that when the key element is pushed into the key channel it is lifted by the ramp surface (24) and hits the ramp surface acentrically. A method for producing a key element according to any one of claims 1- 19, wherein a prefabricated product is punched out with a prefabricated contour, wherein - 29 - the preliminary product contour contains the contour (60) of the key shank, and the ramp surface (24) and a second ramp surface ( 24) is created by guiding this cutter over the key tip (23).