The invention relates to a locking arrangement and to the associated key.
A locking arrangement having a lock cylinder and an associated key, in particular flat turning key, is known in the prior art. In this case, the core of the lock cylinder has a keyway which is open in the direction of the end side of the cylinder and is provided with profile ribs/grooves. The vertex of a conical opening, which opens in the direction of the end side of the cylinder, is located in the centre of said keyway. At its insertion end, the key forms a tip with flanks in the form of arcuate lines. The combination of conical opening and tip with arcuate flanks is intended to facilitate the introduction of the key into the keyway. The introduction of the key is complicated, in particular, in the case of flat turning keys with narrow profile ribs/grooves. On account of the profilings located closely adjacent to one another, the key has to be inserted without deviating to any great extent from the precisely aligned position. Furthermore, locking systems profiled in this way barely allow any positions in which the key axis is inclined to any greater extent in relation to the keyway axis.
The prior art also proposes a solution in which, rather than being rounded, the key has a tip formed by two rectilinear flanks.
The object of the invention is to facilitate the introduction of a key into the keyway.
According to the invention. The tip is formed by two arcuate lines, of which the point of intersection is located in the broad-side centre of the key, and the tangent angle at the point of intersection is greater than the vertex angle of the cone opening, it being the case that the arcuate lines have bevels, in the direction of the mutually opposite broad sides, having a bevel angle which is smaller than the vertex angle of the cone opening. The conical opening forms a type of funnel which opens out into the keyway. The key is inserted in said funnel. It is generally the case that the key axis is not in alignment with the keyway axis. Rather, the key axis is tilted by an angle of inclination in relation to the keyway axis. It is likewise the case that the key shank is rotated by an angle of rotation in relation to the orientation of the keyway. In the rotated position, the arcuate lines are in tangential contact with the cone wall within a broad-side pivoting region. This broad-side pivoting region is bounded by the pivot position in which the tip of the key shank, which is formed by the point of inter-section of the arcuate lines, comes into abutment against the cone wall. Within the broad-side pivoting region, the key tip is spaced apart from the vertex of the cone and projects therein in a contactless manner. The key may also be pivoted through a narrow-side pivoting region in relation to the keyway axis. The narrow-side pivoting region is bounded by the bevel angle. Within the narrow-side pivoting region, the key, with its tip located, in the cone, can be pivoted to the extent where the bevels come into abutment against the cone wall. If the key is inserted into the cone in a state in which it is rotated in relation to the orientation of the keyway, then the pivoting into the above-defined broad-side pivoting region is simplified by the geometry. The user feels the pivot angle at which the tip moves away from the abutment against the cone wall. If the user has the key in this broad-side pivoting region and rotates the key, then the key tip finds its correct, central position in relation to the keyway and with the correct rotary orientation, on account of the bevels, can be inserted into the keyway. The slopes of the bevel which then take effect cause the key to be righted into the aligned position. If the key is rotated out of a position in which the key axis is located in the broad-side pivoting region, until the correct rotary orientation has been reached, then the narrow side is also oriented in the narrow-side pivoting region. This means that, in this position, it is only the end edges of the flank which butt against the cone wall. In a preferred configuration, the bevel angle is greater approximately by 15 to 25xc2x0 than half the vertex angle of the cone. The thickness of the non-bevelled flank section is approximately half to a third of the narrow-side thickness. The result of this is that the key, located in the correctly oriented position, then, upon further pushing in the keyway, is pivoted virtually automatically out of the inclined position into the aligned position, if its inclined position is located within the narrow-side pivoting region. The arcuate lines are preferable circle arcs. The centres are located in the broad side of the key and are spaced apart from the broad-side centre line by a distance. This distance corresponds approximately to 30 to 35% of the broad-side thickness of the key. Furthermore, the radius of the arcuate side is preferably approximately 105 to 110% of the thickness of the broad side of the key. The diameter of the cone opening is preferably smaller than the broad-side thickness of the key. The cone angle, that is to say the vertex angle of the funnel-shaped opening, is preferably approximately 110xc2x0. A development of the invention relates to the cone opening of the cylinder core. The vertex angle of the conical opening is greater on the outside of the opening than in the centre of the opening. The opening preferably forms an inner cone with a smaller vertex angle than the outer cone. According to one development, the inner cone is in the form of an oval. The oval is directed longitudinally in relation to the keyway. This produces, in the region of the keyway, a step-shaped transition between the two cone walls. In the direction transverse to this, the transition is formed as an edge. The vertex angle of the more pointed, inner cone, is preferably 90xc2x0.
The invention also relates, in particular, to a key for the locking arrangement described.