Key or key blank, production method and lock system

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

[0001] The invention relates to a key element, namely a mechanical key or key blank, a method for manufacturing such a key element, and a locking system with a locking cylinder and key element.

[0002] Lock cylinders consist of a stator (sometimes called the "cylinder housing") that is fixed to a lock and cannot rotate, and a rotor (sometimes called the "cylinder core") that rotates around the cylinder's axis when a matching key is inserted. The rotation of the rotor moves drive elements that actuate a bolt or other mechanisms related to the desired function of the lock cylinder.

[0003] Many mechanical lock cylinders for reversible flat keys, or other flat keys, feature tumbler-counter-tumbler pairs that query the mechanical coding of the key. The mechanical coding is represented by holes of varying depths, depending on the coding, primarily on the flat side of the key. The number of possible tumbler lengths, together with the number of holes, determines the number of possible permutations, which should be as large as possible.

[0004] For flat keys with coding recesses (coding holes, coding grooves) on at least one flat side (key face), the following situation arises: The difference between various pin lengths (lengths of tumblers) cannot be arbitrarily small, otherwise a clear locking effect will occur if the coding does not match. Therefore, the maximum depth of the coding recesses in the key ultimately determines the number of possible tumbler lengths. For this reason, it is already known that coding recesses can be so deep that they penetrate a central plane of the key shaft, i.e., that they are deeper than half the thickness of the key shaft. Such coding recesses, especially coding holes, are sometimes called "paracentric."For a lock cylinder with paracentric pins to function correctly, it must be ensured that the pins projecting beyond the center plane of the key shaft – and thus also beyond the corresponding keyway in the lock cylinder – do not obstruct the insertion of the key into the keyway. Depending on the design of the radially inner pin ends, this may require a running surface at the front end of the key, i.e., the key tip, for example, by rounding the key towards the tip or by making it flat towards the front.

[0005] In the field of locking systems, the manufacturer typically supplies key blanks to authorized dealers directly from the factory. These key blanks feature, for example, locking system-specific security features and sometimes also codes customized for the respective dealer, such as a profile. The dealer then creates customized keys for its customers by adding coding holes to the key blanks. The security features already present on the key blank, which differ from simple coding holes, are generally particularly advantageous because they are less easily copied by unauthorized key duplicators than coding holes in the flat side of the key. This ensures that only authorized dealers supplied with blanks by the manufacturer can produce keys.The shape of the key tip is a security feature already present on the key blank and therefore cannot be copied with key copying machines.

[0006] From EP 3 822 434 A1, a key blank for manufacturing a reversible key blade for use with a cylinder lock with radial pins is known. Each side of the key blade of the blank has a V-shaped groove profile that extends over most of the length of the coding portion of the blade. During the coding of the key, coding recesses are formed in each flank of the groove. Each coding recess has a coding depth from a predetermined series of coding depths. The flank surfaces form the basic coding of the coding scheme.

[0007] From EP 2 094 922 A1, a locking system is known that comprises security reversible keys and corresponding cylinders. The keys and their blanks have a concave recess at the key tips, which interacts with a convex protrusion on a sliding counterpart in the cylinders. When the key is fully inserted, the concave recess lies flat against the convex protrusion on the counterpart, and a key without this concave recess is locked out by the convex protrusion of the counterpart, thus preventing complete insertion. This also enables the counterpart to perform a locking or switching function. Starting from the key tip, the concave recess has an initial inclination and then a second inclination towards the key axis, the second inclination being greater than the first. These difficult-to-copy concave recesses are already present on the key blanks.This creates a blank protection and increases the security and permutation capacity of the locking system.

[0008] From EP 1 251 223 A1, a key of a master key system is known, wherein a master key forms a longitudinal rib which has a control ramp for a control projection of a locking element of a cylinder at the insertion-side end and a control recess downstream of this control ramp, wherein a single key forms a longitudinal rib which ends bluntly to the insertion direction and otherwise has a constant cross-sectional contour.

[0009] From EP 2 317 040 A1, a reversible flat key for a lock cylinder is known, with a key tip forming a fork opening and having two control flanks spaced apart from each other by a channel for engaging control zones of a core pin of the lock cylinder, the bottom of the channel forming a ramp for the tip of the core pin. The ramp is associated with a high rib of the key flanked on both sides by grooves. Opposite the high rib is a low rib with inclined walls. The control flanks are associated with the bottoms of the grooves. To improve the locking mechanism of a key of this type, the invention proposes that the control flanks extend to the inclined walls of the low rib.

[0010] A security reversible key is known from WO 01 / 77466 A1. The security reversible key with an associated cylinder has a block groove with a coded block depth, which runs parallel to the key axis from the key tip to at least the first position of a row of tumblers on the key. In the associated cylinder, at least at the rearmost coding position, a pair of tumblers corresponding to the block groove is provided, consisting of a block tumbler and an extended block counter-tumbler. The block counter-tumbler rests against the cylinder sleeve if the block groove is too shallow, thus preventing the full insertion of a key with an insufficiently deep block groove by the block tumbler pair. Simultaneously, the block tumbler and counter-tumbler at this position also serve as the coding tumbler.

[0011] However, a raised surface at the key tip can increase the cost of manufacturing mechanical flat keys, as it necessitates additional, more complex machining steps beyond stamping out the outer contour and milling grooves for profiling. Furthermore, it can create a sharp edge at the key tip, which can be detrimental to both usability and wear over time.

[0012] 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 running surface at the key tip which is relatively easy to manufacture and which is as advantageous as possible with regard to wear and user-friendliness.

[0013] This problem is solved by the invention as defined in the patent claims.

[0014] The invention relates to a key element (key or key blank) with a rear key bow and a key shaft extending along a key axis from the key bow to a front key tip, the shaft having two parallel flat sides and two opposing narrow sides. On the side of the key tip, i.e., the front side, the key shaft has a ramp. This ramp extends over more than half the key thickness, i.e., at at least one lateral position (in particular corresponding to the position where the main pin row is arranged in the locking system), the ramp projects from one of the flat sides through the median plane between the flat sides to a front projection at the key tip or laterally thereto on the front of the key.

[0015] The ramp surface can extend from the front end of the key, which forms the contour, to a transition into the flat side. Because it extends at least partially to below a central plane of the key shaft on the front side, even pins with a small diameter and / or only a slightly rounded radial-inner end that extend particularly far into the keyway cannot block the insertion of the key.

[0016] 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; in particular, it does not have to be pointed.

[0017] The key element has a distinctive contour on its front face. In a projection perpendicular to the flat surfaces, the contour forms a straight, central section at the front and a second, at least partially curved section towards one side, extending to and merging with the narrow side. This second section is set back relative to an arc line, which is defined by having a constant radius and having a tangent to the first section at the transition point and a tangent to the narrow side at the transition point.

[0018] The arc line is a hypothetical, imaginary arc line, i.e. the contour of the key does not have this arc line, but is offset to the rear relative to it.

[0019] The key element can in particular be a reversible key blank or a reversible key, i.e. at least the key shaft is then symmetrical with respect to a rotation of the key element by 180° around the key axis.

[0020] The contour will be symmetrical, especially if the key element is a reversible key element. In the presence of symmetry, there is a second section of the type defined above on each side. All statements made in this text regarding the shape of the contour are to be understood as also applying to correspondingly symmetrical contours, and all statements in this text regarding the shape of the key element apply specifically to reversible key elements, i.e., key elements whose shank is symmetrical with respect to a 180° rotation about the key axis. The key bow may also exhibit this symmetry, but this is not necessary for its function.

[0021] This contour, combining a straight front section with a lateral section that is at least partially curved but set back from the aforementioned arc line, has proven advantageous. Firstly, the straight front section allows for maximizing space for a number of codings near the key axis—that is, near the center—both in terms of the available space on the key and the potential depth of the coding holes (keyword: 'paracentricity'). Secondly, the shape with the partially curved section is well-suited for the efficient production of a stamping blank using a stamping process.Thirdly, by setting the contour back from the aforementioned arc line, the following is ensured: Even if the ramp surface is flat (which can be advantageous from a manufacturing perspective, see remarks below) and relatively steep (which saves valuable space on the key), no sharp edge results on the front. Such an edge would occur if the contour were not set back. Fourthly, the shape is also otherwise free of sharp edges or corners.

[0022] The running surface can be flat, and / or it can be inclined in two directions relative to the normal to the flat side, i.e., a normal to the running surface is inclined both forwards and laterally relative to the normal to the flat side. This condition applies, for example, at least to the positions at the distance (y-position) from the vertical plane through the key axis (vertical mid-plane) at which the pins of the main pin row graze the running surface when the key is inserted. This causes the pins to strike the running surface acentrically at their radially inner end, i.e., not centrally with respect to their pin axis, but on one side. This has the first consequence that the pin is slightly pressed laterally, i.e., in the y-direction, which is why, even with a small amount of play, it is guided in a better-defined position compared to the prior art.Secondly, this prevents the tip (the radially inward end) of the pin from rubbing against the running surface. Instead, if the pin tapers radially inwards or is rounded, it rests against the running surface laterally and can at least partially roll along it. This means that inserting the key can cause the pin to rotate around its axis. This reduces the mechanical resistance when inserting the key. Furthermore, wear on the pin is distributed more evenly compared to the prior art.

[0023] The y-position of the main pin row (e.g., main tumbler row) is defined by the lock cylinder, but also by 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 several such rows are present, the row with the most and / or deepest coding holes (main row). If the key element is a key blank without the coding holes, the y-position of the main pin row can be determined according to the y-position of the main row of coding holes in the following embodiments: Starting from the vertical plane through the key axis, the running surface of a reversible key indicates on which side of this vertical plane the main row is located. If the key blank is profiled (i.e.,If the cross-section perpendicular to the key axis is not rectangular but rather has ribs and grooves running parallel to the key axis, then the y-position of the main pin row can correspond to the y-position of the rib that is closest to the vertical plane through the key axis on the corresponding side.

[0024] The second section can have several subsections. For example, there can be a first subsection with a first radius of curvature R1, as well as at least one further subsection that has a second radius of curvature R2, which is larger than R1, or that is straight. The first subsection connects to the first section at the front.

[0025] The radius of curvature R 1 of the first subsection can in particular be smaller than the width b of the area of ​​the key shaft between the first section and the narrow side.

[0026] According to the invention, the second section has a tangent to the first section that coincides with it, i.e., at this transition the contour can be considered as a function continuously differentiable, i.e., "kink-free".

[0027] Additionally or alternatively, the transition between the second section and the narrow side can also be "kink-free", i.e., the tangent to the second section at the transition to the narrow side can coincide with the narrow side.

[0028] The second section can, in particular, have the following sequence from the first section towards the narrow side: the first subsection with the first radius of curvature R1, a second, straight subsection, and a third subsection with the larger radius of curvature R2. In an otherwise identical configuration, the second subsection can also be curved instead of straight, with a radius of curvature larger than the radii of curvature of the first and third subsections.

[0029] As already mentioned, offsetting the contour relative to the aforementioned arc line does not result in a sharp edge on the front side. A feature of the present invention is that, instead, a front surface is defined which is perpendicular to the flat sides and forms a front end of the key shaft, the front surface transitioning at both ends into the narrow sides parallel to the key axis.

[0030] The front surface thus extends from one narrow side with the contour according to the invention to the other narrow side. The front surface can be continuous or interrupted by grooves running parallel to the key axis to the front end.

[0031] At its narrowest point, the front surface can be at least 0.05 mm, preferably at least 0.08 mm, and particularly at least 0.12 mm high. The maximum height at its narrowest point can be, for example, 0.5 mm or 0.3 mm. In this text, "height" refers to the dimension perpendicular to the flat sides; according to the coordinate system used here, that is, the dimension in the z-direction.

[0032] If the front surface is interrupted, a narrowest point may not be defined. Therefore, the following condition generally applies: the transition between the ramp surface on the one hand and the front surface on the other 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, and particularly at least 0.12 mm. The maximum distance at the point where the transition is closest to the opposite flat side can be 0.8 mm, preferably 0.6 mm, and most preferably 0.4 mm.

[0033] Both conditions (the condition for 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, but rather that at every position along the width (every y-position) there is a gap between the ramp surface and the opposite flat side. This gap is defined by the front surface or, if present, by a groove interrupting it and extending to the front edge.

[0034] In certain areas, the ramp surface may transition into the front surface, with the front surface forming an upper or lower edge ("upper" and "lower" are to be understood in relation to the z-direction) of the key shaft and / or transitioning directly into the flat side. In other words, in a lateral section (at a y-position), the key tip is unilateral, meaning that ramp surfaces are not present on both flat sides, but only on one, while the front surface directly adjoins and transitions into the other flat side.

[0035] In a width section behind which a series of coding holes is provided in the x-direction on the (finished key) - i.e. at the y-position of a series of coding holes, in particular at the y-position of the centers of the coding holes - the ramp surface can transition into the front surface and the front surface can form an upper or lower edge of the key shaft and / or transition directly into the flat side.

[0036] The front surface can include an end surface at the key tip, which has edges parallel to the planes defined by the flat sides (and correspondingly to the median plane 19, which is parallel to these). The parallel edges can, in particular, have a spacing of at least 0.5 mm, and more specifically at least 0.7 mm. A maximum spacing can, for example, be 1.5 mm or 1.2 mm.

[0037] Instead of a rounded or pointed structure, as known from the prior art, a key element of the type described here can have an end face at its very front, which is preferably perpendicular to the key axis. The shape of the end face can be that of a rhomboid, with long sides inclined to the central plane and short sides perpendicular to the central plane.

[0038] An end surface at the key tip can be located at least between two width sections, behind which the centers of the coding holes are provided in the x-direction.

[0039] The front surface can include a (continuous or interrupted) transition surface to the side of the end surface. In at least one width segment (within the area of ​​the transition surface), a first edge of the front surface can be designed as a transition to the flat side, and the second edge can be curved. The transition surface can, for example, adjoin the end surface. In particular, a continuous or interrupted transition surface can be provided on each side of the end surface. The transition surface adjoins the end surface towards the center and the corresponding flat side towards the sides, but, like the end surface, it is also perpendicular to the central plane (and correspondingly to the flat sides).

[0040] In a top 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 from each other in width; and / or wherein the first and second edges include a local extremum.

[0041] If the key element is a reversible key element, the ramp surface - more precisely: the two ramp surfaces arranged symmetrically to each other - can 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 obliquely over the key tip, i.e. in a direction of movement perpendicular to the key axis and at an angle other than 0° to the horizontal center plane.

[0042] The milling tool can be positioned in such a way that there is no sharp edge on the front of the key, but rather an end surface whose width - perpendicular to the direction of movement of the milling tool - results from the distance of the axis of rotation from the key tip during the milling machining step.

[0043] The key element can be a key, specifically a flat key, in particular a reversible key. This key has at least the main row of coding holes – in addition to the main row, further coding holes may be present. Alternatively, the key element can also be a key blank, in which case, besides the striking surface, a profile may already be present on the key blank.

[0044] The invention also relates to a locking system which, in addition to a key element, also has a locking cylinder matched to it. Such a cylinder, in a manner known per se, has a locking cylinder stator and a locking cylinder rotor with a keyway into which the key shaft can be inserted. Pins in the locking cylinder allow the scanning of coding holes on the key element—if it is a finished key, otherwise as soon as these holes are installed. The pins in the locking cylinder can, in particular, be tumblers in the locking cylinder rotor, which interact with counter-tumblers in the locking cylinder stator and only allow rotation of the locking cylinder rotor if the depth of the coding holes is correct. The pins of at least the main row (i.e.,The pins in the row whose position corresponds to the main row of coding holes (in reversible key systems, these will be distributed across the corresponding rows on both sides of the key) are lifted by the ramp surface when the key is inserted. The pins encounter the ramp surface particularly acentrically, which is why they can at least partially roll along it during insertion and do not necessarily rub against it.

[0045] Instead of tumblers, or especially in addition to them, the lock cylinder may also have other pins that scan the key's coding, in particular profile pins or profile wobble pins.

[0046] The invention also relates to a method for manufacturing a key element with the principle described above, in which a pre-fabricated part, optionally before or after the profiling has been carried out, is provided in a single step with the two mutually symmetrical ramp surfaces also described, which are necessary for a reversible key system, by means of a milling profile.

[0047] In this text, "coding hole" refers to a recess in the key whose dimensions are chosen based on a desired coding. Coding holes can be created by drilling; however, corresponding recesses produced by other methods are also referred to here as "coding holes."

[0048] In this text, the orientation terms "radial," "radial-in," "axial," etc., generally refer, unless otherwise stated, to the key axis, which, in a locking system, also corresponds to the cylinder axis when the key is inserted. "Front" refers to the position towards the key tip, and "back" accordingly refers to the position towards the key bow.

[0049] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings. In the drawings, identical reference numerals denote identical or analogous elements. The drawings show: Fig. 1 a perspective view of a key; Fig. 2 a corresponding view of a key blank for making a key according to Fig. 1 Fig. 3: A sectional view of a section of a lock cylinder during the insertion of a key; Fig. 4: A view of the foremost area of ​​the key blank according to Fig. 2Fig. 5 shows a view of the key blank according to Fig. 2 from the front; Fig. 6 a schematic representation of a milling tool; Fig. 7 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; Fig. 8 a representation of the contour of the foremost area of ​​the key or key blank; and Fig. 9 a view of another key blank.

[0050] Figure 1 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 that the key shank is essentially non-square rectangular in cross-section perpendicular to a key axis 10, thus defining two parallel flat sides 21 and two narrow sides 22 with a smaller area than the flat sides 21. An edge 25 is formed between each of the flat sides 21 and the narrow sides 22.

[0051] Fig. 1 This also shows the Cartesian coordinate system used in this text, where the x-direction is parallel to the key axis and the z-direction is perpendicular to the flat sides 21.

[0052] The key shaft 12 has at least one row of coding holes 31 running parallel to the key axis 10.

[0053] In addition to the coding holes 31, 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 for the locking system and only exclude keys from other locking systems) and / or variation profile grooves (which form a code) may be present. Corresponding ribs 33 are formed between the grooves 32.

[0054] The illustrated key 1 is a reversible key, i.e. the key shaft is symmetrical with respect to a rotation of 180° around the key axis 10, and the codings on the front and rear flat sides 21 are accordingly identical.

[0055] In contrast to the illustrated embodiment, the key may 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 may also have coding holes on the narrow sides 22.

[0056] In the illustrated embodiment, the key also has a plurality of coding recesses 35, which are formed as abrasions along the edge 25.

[0057] Figure 2 shows the key blank 2, from which the key is manufactured by adding the individual coding holes 31 and, if necessary, coding recesses 35.

[0058] Towards the key tip 23, the key has a forward-sloping ramp surface 24, which allows the lock cylinder to have pins (e.g., tumblers) that scan the coding holes and extend further into the keyway than to the central plane. This principle is in Figure 3Figure 40 schematically illustrates a cross-sectional view of a locking cylinder 40 with a locking cylinder rotor 43 rotatable within the locking cylinder stator 44 and featuring a keyway 45. The locking cylinder rotor has multiple rotor pin bores, each with a pin forming a tumbler 46, the length of which depends on the coding. Corresponding spring-loaded counter-tumblers 47 are arranged in stator pin bores that are aligned with the rotor pin bores in the rotor's home position. The lengths of the tumblers 46 and counter-tumblers 47 of each tumbler-counter-tumbler pin pair can be combined to form an equal overall length.In a manner known per se, a suitably coded key can align the interface between the tumblers and counter-tumblers with the shear surface between the rotor and stator, thus enabling the rotor to rotate away from the stator around the cylinder axis, which corresponds to the key axis 10 when the key is inserted.

[0059] As particularly in Figure 4The ramp surface 24 is shown to be essentially flat. Furthermore, it not only slopes forward towards the key tip 23 in the manner of a ramp, but is also inclined radially outwards. In other words, the normal N to the ramp surface (e.g., at least at the y-position corresponding to the y-position of the row of coding holes 31 or at least one of the rows of coding holes) forms both an angle (α) with the xy-plane (the plane parallel to the flat sides) and an angle (β) with the xz-plane (i.e., the plane parallel to the key axis 10 but perpendicular to the flat sides 21).

[0060] This inclination towards the xz-plane of the ramp surface 24 ensures that even longer pins projecting into the keyway are reliably lifted and pushed radially outwards, even against a spring force if necessary. It also ensures that the pins do not strike the ramp surface centrally (i.e., in the middle with respect to their pin axis) at their radially inner end, but rather on one side. Firstly, this results in the pin being slightly pressed laterally, i.e., in the y-direction, which is why, even with a small amount of play, it is guided in a better-defined position compared to the prior art. Secondly, it prevents the tip (the radially inner end) of the pin from rubbing against the ramp surface. Instead, the pin, if it is, for example, Fig. 3shown as tapering radially inwards, abutting the running surface laterally and rolling at least partially along it, i.e., the insertion of the key will cause the pin to rotate around its pin axis.

[0061] The running surface 24 is of particular importance at the position where the pins of the main locking row run up when the key is inserted. In the key and key blank shown, this corresponds to the position of the first rib 34 viewed from the center (i.e., from the vertical median plane, i.e., the xz-plane through the key axis), see Fig. 4 The run-up surface is designed so that at this y-position it extends significantly below the horizontal mid-plane 19 (the xy-plane through the key axis), which can be seen in Figure 5 looks especially good. Fig. 5This shows a view of the key blank 2 from the front, i.e., from the key tip 23. P indicates the position of the main tumbler row – corresponding to the position of the coding holes 31 of the main row, see [reference]. Fig. 1 , designated.

[0062] A further advantage of the key and key blank according to the invention lies in the simpler manufacturability of the key blank 2 and thus also of the key 1 compared to the prior art. The two with respect to the key axis (in Fig. 5 Symmetrical ramp surfaces 24 (perpendicular to the drawing plane) can be produced in a single operation from a stamped pre-fabricated part (stamped blank) before or after the profiling is applied. This is because they can be produced by a milling tool 51 with a concave V-milling profile (schematically shown in Figure 6The tool is shown with rotation axis 52 and cutting section 53; opening angle of the V-profile: δ) which moves across the key tip at an angle ε to the xy-plane other than 0°, at such a distance that a surface of width d remains behind on the front side. The movement takes place perpendicular to the main axis (rotation axis 52) of the milling tool, i.e., the angle ε is the angle between the xy-plane and the plane perpendicular to the rotation axis 52 of the milling tool during the milling process. Figure 7 shows the corresponding milling cutter contour on the key blank.

[0063] Accordingly, the rotary axis 52 of the milling tool is set at an angle ε to the vertical (to the z-axis) during the milling machining step.

[0064] In the illustrated embodiment, δ = 70° and ε = 35°, and d = 0.8 mm; the angles α and β are also defined by this choice of machining angles δ and ε. Overall, it is preferred if 55° < δ < 90° and 25° < ε < 45°.

[0065] In Fig. 5 It can also be seen that the milling profile is positioned so that a strip of width d (measured perpendicular to the direction of movement) remains at the key tip. Therefore, there is no sharp edge at the key tip, but rather an end surface 26. The width d of the milling profile shown is determined by the appropriately selected distance of the axis of rotation 52 from the key tip 23 during the milling operation.

[0066] The end surface 26 comprises, as can also be seen in Fig. 5 good view, diagonally to the middle plane 19 (in Fig. 5 Edges running perpendicular to the plane of the drawing) which are parallel to each other, so that the end surface 26 has the shape of a rhomboid.

[0067] Figure 8 Figure 1 shows the outer contour 60 of the pre-fabricated part from which the key blank is manufactured, in the area of ​​the foremost part of the key shaft 12, i.e., in the area of ​​the key tip, viewed from the flat side, i.e., in a projection onto the xy-plane. The outer contour 60 is not, or at least not significantly, changed by milling the ramp surfaces 24, applying the profile with the grooves 32, and also by applying the coding holes and, if applicable, coding recesses, so that the outer contour 60 also corresponds to the outer contour of the key blank 2 and the key 1.

[0068] Since key 1 is a reversible key, the outer contour 60 must also be symmetrical with respect to the key axis 10, i.e., (as a two-dimensional contour) with respect to a central axis. From the key tip (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 extends from the straight first section 61 to the narrow side 22 and which is curved at least in part.

[0069] In the illustrated embodiment, it can also be seen that the second section 62 has three distinguishable subsections, namely, from the inside out, a first, curved subsection 63 with a first radius of curvature R1, a second, straight subsection 64, and a third, curved subsection 65 with a second radius of curvature R2, which is larger than the first radius of curvature. The dashed lines in Fig. 8 show an imaginary division between a central area, which is bounded at the front by the straight first sections 61 on both sides, and the two side areas with width b, which are bounded at the front by the second section 62.

[0070] In Fig. 8A hypothetical contour 69 is also shown, which would result if, starting from the straight first section (which is advantageous because it provides as much space as possible for the row of essential coding holes), there were only a single curved section whose radius Rb corresponds to the width b. This follows from the condition that the tangents at the transitions to the first section 61 and the narrow side 22 therefore coincide with the first section 61 and the narrow side 22, respectively (i.e., they run perpendicular and parallel to the key axis; the contour, conceived as a function, is also continuously differentiable at the transitions). It can be seen that the contour 62 is slightly offset backwards relative to this hypothetical contour 69, without changing the overall length of the key in the important central area.

[0071] This offers an important advantage: When using the Figure 5-7The described shape of the contact surfaces would result in a sharp edge at the thinnest points on the front side of the hypothetical contour 69 (corresponding approximately to the area of ​​the second subsection 64). Such an edge is undesirable. Firstly, because the sharp edge could damage trouser pockets or other textiles that come into contact with the key. Secondly, a sharp edge is also undesirable from the perspective of wear and tear that will occur over the years. Recessing the contour in this area prevents such a sharp edge, as can be seen, for example, in Fig. 4 It is clearly visible where the front surface 27 of the thinnest (narrowest) point is clearly visible.

[0072] Even at its narrowest point, the front surface can be at least 0.05 mm, preferably at least 0.08 mm, and particularly at least 0.12 mm high (extent in the z-direction). In addition to the end surface 26, the front surface 27 also includes a transition surface 28 on each side, which extends from the end surface 26 in an arc to each of the narrow sides 22 and merges into them. Thus, the front surface extends, for example, continuously from one narrow side to the other. The front surface 27 forms a front termination of the key shaft.

[0073] The offset of contour 60 relative to the hypothetical contour 69 results from the fact that the first subsection 63 has a smaller radius of curvature R1 than the width b and / or that the transition between the first region 61 and the second region forms a slight kink, i.e., that the tangent to the second region 62 at the transition to the first region 61 is not parallel to the first region 61. In the example shown, at least the condition R1

[0074] As one can also in Fig. 4 and 5 ​As can be seen particularly well, the ramp surface 24 transitions in some areas into the front surface 27. In a lateral section (particularly at position P of the main coding series, especially in the area of ​​the transition surface 28), the front surface 28 transitions directly into the corresponding flat side 21 on its upper or lower side, while on the opposite side, i.e., on its lower or upper side, it transitions into the ramp surface 24 in this lateral section. In this lateral section, the front surface thus forms an upper or lower edge of the key shaft.

[0075] 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 represent a transition into the respective flat side, and the other edge runs as shown in Fig. 5 It looks good, arched.

[0076] In the top view according to Fig. 5 It can also be seen that the two edges which extend the front surface 27 upwards and downwards on the key (in Fig. 5 (i.e., to the left or to the right) limit, have disappeared as a whole, wherein the first and second edges are offset from each other in width (y-direction); wherein the first and second edges encompass a local extremum.

[0077] Figure 9 Figure 1 shows a perspective view of the key shaft 12 of a variant of a blank for a reversible key. As in the other described embodiments, the features of the key shaft described in this text are designed such that symmetry with respect to a rotation about the key axis by 180° results.

[0078] Of the embodiments of the Figure 4 and 5 The key blank differs from Figure 9In particular, this is achieved by arranging one of the grooves 32, which run parallel to the key axis to the very front, in the flat side 21 on each flat side such that it interrupts the front surface 27 in the area of ​​the transition surface 28, so that the transition surfaces 28 on both sides of the end surface 26 are each divided into two partial surfaces, between which the respective groove 32 lies. Therefore, no narrowest point of the front surface 27 and, accordingly, no minimum height is defined. However, even in these embodiments, the condition arises 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, and that the key blank (and, accordingly, the key made from it) is not rounded on the front side, but rather that a front surface perpendicular to the flat side is formed between the ramp surface 24 and the flat side 21.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 The lower flat side is the one for the ramp surface 24 shown on the right, and the upper flat side 21 is the one for the ramp surface 24 shown on the left. The thickness is always different from zero and is more than 0.05 mm, preferably at least 0.08 mm, and in particular at least 0.12 mm.

Claims

1. A key element (1, 2) having a key blade (11) on the rear side and a key shank (12) extending along a key axis (10) from the key blade (11) to a key tip (23) on the front side and having two flat sides (21) parallel to one another and two narrow sides (22) opposite one another, wherein the key shank (12) has, towards the key tip (23), a run-up surface (24), which runs from one of the flat sides (21) through a central plane (19) between the flat sides to an extension on the front side, wherein the key shank has a contour (60) on the front side in a projection perpendicular to the flat sides (21), which contour has a central, straight first section (61) on the front side towards the key tip and a second section (62) which is curved at least in regions and which runs from the first section (61) to one of the narrow sides (22), and in that the second section (62) is set back towards the rear side relative to a curved line (69) running continuously from the first section (61) to the narrow side (22), wherein the curved line (69) has a constant radius and, at a transition to the first section, has a tangent coinciding with the first section and, at a transition to the narrow side, has a tangent coinciding with the narrow side such that a surface (27) on the front side is defined, which is perpendicular to the flat sides (21) and forms an end of the key shank (12) on the front side, wherein the surface (27) on the front side merges at its two ends into the narrow sides (22) parallel to the key axis (10).

2. The 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 R1 and at least one further subsection (64, 65) which has a second radius of curvature R2, which is greater than the first radius of curvature R1, or which is straight.

3. The 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 (65) extending between the second subsection and the narrow side (22) and / or wherein the third subsection (65) has a radius of curvature R2, which is greater than the first radius of curvature R1, and / or wherein the first sub-section (63) has a constant radius and has a tangent coinciding with the first section (61) at a transition to the first section (61).

4. The key element according to one of the preceding claims, wherein the run-up 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-up surface (24) is inclined both forwards and to one side relative to the normal to the flat side.

5. The 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 has, in addition to the run-up surface (24), a second run-up surface (24) symmetrical to the latter, wherein the run-up surface (24) and the second run-up surface (24) are formed and arranged such that they are produced by the removal of material by means of a milling tool (51) with a concave V-shaped milling profile, which is guided in a direction of movement over the key tip (23), which direction of movement runs perpendicular to the key axis and at an angle (ε) to the flat sides which is different from 0°.

6. The key element according to one of the preceding claims, which is flat at the key tip by having an end face (26) on the front side which is preferably perpendicular to the key axis (10).

7. The key element according to claims 1 to 6, wherein a minimum distance (a) between a transition between the run-up surface (24) and the surface (27) on the front side on the one hand and a plane of the opposite flat side (21) on the other hand is at least 0.05 mm, preferably at least 0.08 mm, particularly preferably at least 0.12 mm.

8. The key element according to claims 1 to 7, wherein it is provided in regions that the run-up surface (24) merges into the surface (27) on the front side and the surface (27) on the front side forms an upper or lower edge of the key shank (12) in regions and / or merges directly into the flat side (21).

9. The key element according to one of claims 1 to 8, wherein the end face (26) comprises parallel edges running obliquely to the central plane (19), wherein the edges have, for example, a distance (d) of at least 0.5 mm, preferably at least 0.7 mm.

10. The key element according to claim 9 and one of claims 1 to 8, wherein the surface (27) on the front side comprises the end surface (26) and at least one transition surface (28), wherein a first edge of the surface (27) on the front side is formed as a transition into the flat side (21) and a second edge runs in a curved manner at least in regions, wherein the transition surface (28) adjoins the end surface (26), wherein in particular a transition surface (28) is provided on both sides of the end surface in each case.

11. The key element according to one of the preceding claims, which is formed as a key blank (2) with a profiling, wherein the profiling comprises a plurality of grooves (32) and ribs (33, 34) formed between them.

12. The key element according to one of claims 1 to 10, which is designed as a key (1) with at least one main row of coding holes (31).

13. A locking system, comprising a key element according to claim 12, as well as 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 into which the key shank (12) of the key element can be inserted, wherein the lock cylinder has at least one pin (46) which scans one of the coding holes (31) and releases or does not release a rotation of the lock cylinder rotor (43) depending on the presence and depth thereof, wherein the pin (46) is arranged such that it is lifted by the run-up surface (24) when the key element is inserted into the key channel and in so doing strikes the run-up surface eccentrically.

14. A method for producing a key element according to one of claims 1 to 12, wherein a prefabricated product with a prefabricated product contour is punched out, wherein the prefabricated product contour includes the contour (60) of the key shank, and wherein subsequently the run-up surface (24) and a second run-up surface (24) symmetrical thereto are produced by removal with a milling cutter (51) with a V-shaped milling profile in a single work step, in that this milling cutter is guided over the key tip (23).

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