Field of the invention

This invention relates to disc tumbler lock cylinders and electronic lock cylinders, which are used for locking the doors of buildings.

Prior art

Disc tumbler lock cylinders and electronic lock cylinders are generally used in the doors of buildings. Using both cylinder types, a high level of locking is provided. In the disc tumbler cylinder, disc tumblers located in the inner cylinder form a code, which must be decoded to open the locking of the lock (in which the disc tumbler cylinder is located). Decoding is accomplished with a key comprising a correct code, i.e. millings (a combinatory whole) corresponding to the code of the cylinder. The inner cylinder of an electronic lock cylinder has electronics comprising correspondingly an electronic code. The code opens with a suitable electronic key (a key, which has electronics comprising the decoding of the code of the cylinder). Let it be mentioned that, in this text, by electronic lock cylinder is meant a lock cylinder, in which the entire code of the cylinder is electronic or partially electronic (i.e. the code of the cylinder can be a combination of mechanically achieved code and electronic code).

In some locations of use, outside conditions comprise dust and/or moisture, which attempts to penetrate inside the lock cylinder via the keyhole. In automobile doors are indeed used a keyhole protector to prevent the entrance of dust and moisture into the lock cylinder. Keyhole protectors are, however, not used in the cylinders of the door locks of buildings, as they require space in the longitudinal direction of the lock cylin- der, and as installed they may make lockpicking easier, which weakens lock security. Let it additionally be mentioned that the thickness of car doors is relatively great, thus inside a car door is plenty of space for the lock, the lock cylinder as well as the keyhole protector. Brief description

The object of the invention is to provide a lock cylinder for the door locks of buildings such that the lock cylinder has a keyhole protector and the lock security of the lock cylinder remains nonetheless the same as in known lock cylinders. The object is achieved in the manner presented in the independent claim. The dependent claims describe various embodiments of the invention.

In the invention, a keyhole protector is combined with the drilling protector of the lock cylinder. The drilling protector is a part in the front part of the lock cylinder at the site of the keyhole, which is free to rotate in relation to the lock cylinder and the inner cylinder of the lock cylinder at least then, when an attempt is made to drill it.

List of figures

In the following, the invention is described in more detail by means of the figures of the accompanying drawings, in which drawings,

Fig. 1 shows an example of a lock cylinder according to the invention,

Fig. 2 shows an example of a keyhole protector according to the invention as an exploded view, and

Fig. 3 shows an example of the inner cylinder of a lock cylinder according to the invention.

Description

Fig. 1 shows an example of a lock cylinder 1 according to the invention. The lock cylinder is either a disc tumbler lock cylinder or an electronic lock cylinder. Thus, the complexity of the code of the lock cylinder is to be preserved even though to the front side/front surface 1A of the lock cylinder is placed a keyhole protector 2. In pin tumbler cylinders, the key canal protector would shorten, i.e. would weaken the code of the cylinder. The key canal protector is combined with an as such known drilling pro- tector. As was already mentioned above, the drilling protector is free to rotate in relation to the lock cylinder and its inner cylinder, in the event that an attempt is made to drill it. The drilling protector is generally hard/hardened metal. Thus, penetration of the drill bit up to the inner cylinder is effectively prevented. Thus, a key canal protec- tor according to the invention can also be hard/hardened metal. As is observed from the figures, the drilling protector and, further, in a structure according to the invention, also the key canal protector are placed at the site of the key canal of the lock cylinder forming thus a part covering the inner cylinder. The combined drilling protector and key canal protector take in the longitudinal direction A of the cylinder less space than a separate drilling protector and key canal protector. Thus, also the space reserved for the coding of the cylinder is not reduced. In other words, the lock security of the cylinder remains the same as in known disc tumbler cylinders and electronic cylinders.

Fig. 2 shows an exploded view example of a key canal protector 2. The protector comprises a frame 3 and an overlaying cup 4 on top of the frame such that the front surface 9 of the overlaying cup is visible on the front surface 1 A of the lock cylinder 1. Both the frame and the overlaying cup comprise a keyhole 7, 8. Between the fame and the overlaying cup is placed a spring 6 and a flap 5. The spring is arranged to pivot the flap to cover the keyholes 7, 8. When the key is inserted into the lock cylin- der, the tip of the key pivots the flap 5 against the spring 6, and the key can thus enter into the lock cylinder. When the key is not in the cylinder, the flap prevents the entrance of dust and moisture via the keyhole into the lock cylinder. Both the overlaying cup and the frame are cylindrical in their basic shape. Because the frame 3 is also a sealed structure, except for the keyhole 7 and recesses reserved for the flap 5 as well as the spring 6, lockpicking through the keyhole is as difficult as in known drilling protectors.

From Fig. 2, it is also observed that the frame has a recess 10 for the spring 6 and grooves 11 for the pivoting axis 12 of the flap 5. The pivoting axis is, in this example, a pin on the other longitudinal edge of the flap, which forms projections above and below the flap. In addition, on the front surface of the flap can be at least one convex projection 18 to facilitate pivoting of the flap, when the key is inserted into the lock cylinder.

A keyhole protector as described in the text above is free to rotate feely in relation to the lock cylinder and its inner cylinder. Both the frame and the overlaying cup can be shaped (for example, like cones) such that they remain in the lock cylinder, when they are installed into place. In the example in Fig. 2, the back edge (the back edge is the inwards edge of the cylinder, when the cylinder is inspected from its front side 1 A) of both the overlaying cup 4 and the frame 3 has a projection edge 13, 15, which prevents pulling out the key canal protector from the lock cylinder. In addition, the em- bodiment of Fig. 2 has a cavity 14 of the outer edge in the projection edge 13 of the overlaying cup, and the projection edge 15 of the frame has a projection 16 in the direction of the longitudinal A axis of the cylinder, which projection settles in the cavity 14 of the projection edge of the overlaying cup. Using this solution is prevented, if desired, pivoting of the overlaying cup in relation to the frame 3.

In some installation locations, it can be desirable that the key canal protector 2 is in normal use not free to pivot in relation to the inner cylinder, but is free to pivot in abnormal situations (for example, in a drilling situation as described above). The embodiment of Fig. 2 presents one possible solution to achieve this kind of function. However, let it be noted that such a solution is one additional feature to the basic structure of the invention, i.e. the following description describes one embodiment of the invention. To the projection edge 15 of the frame 3 is further arranged at least one second projection 17, which faces radially away from the centre of the frame and, at the same time, from the keyhole 7 in the centre of the frame 3. In the outer edge (the edge, which is towards the front surface 1A of the lock cylinder) of the inner cylinder 31 (Fig. 3, which shows the inner cylinder as highly simplified) of the lock cylinder is arranged a recess 32 for the second projection. In a drilling situation or other situation, in which an attempt is made to pivot the key canal protector by violent means, the second projection 17 of the frame 3 and/or the outer edge of the inner cylinder is arranged to yield (for example, to break), wherein the key canal protector is free to rotate in relation to the inner cylinder. It is thus obvious that Fig. 2 shows also other features than just those features, which are required to implement the invention. As is obvious on the basis of what is presented above, the invention can be implemented in many different ways, staying however within the scope of the independent claim.