The invention is described below in detail with the help of the attached schematic drawings wherein
In
The lock cylinder is further provided with an access control unit 8 which generates an authorization signal after receiving an access signal from a key or key-card. The access signal may be transmitted via wireless communication. Upon generation of the authorization signal an electric motor drive 7 arranged in a recess of the shaft 1 drives a locking pin 5 into a recess or hole 6 in the socket 4 of the knob 2. The electric motor drive 7 turns an eccentric 13 which moves a rod 14 connected to the locking pin 5. With this arrangement a connection between the knob 2 and shaft 1 is provided. The lock tappet 3 can then be turned by the knob 2.
The locking pin 5 is movable in the shaft 1 in the radial direction between a recessed position and an extended position. The rod 14 is movable against the force of a spring 16 within a sleeve 15 of the locking pin 5. With this arrangement it is possible to move the rod 14 into its extended position, the operating or engaging position, even if the locking pin 5 is not in an aligned position or in an engaged position with the recess or hole 6 of the socket 4 of the knob 2. If the knob 2 is turned until the recess or hole 6 is opposite to or aligned with the locking pin 5, as it is shown in
The authorization signal for operating the electric motor drive 7 is transmitted to the control unit 11 and access control unit 8 by a slip ring arrangement. In the embodiment of
The knob 2 with the access control unit 8 can be easily changed. It is only required to provide a knob with the desired access control technique which can be mounted on the free end of the shaft 1. For further security a drill plate 12 may be provided in front of the locking pin 5 within the shaft 1 in order to prevent drilling and tampering of the locking means. The housing of the lock cylinder preferably has a size such that the recesses or holes 6 are covered. A protection shield (not shown) may be provided which extends to the knob 5 such that the socket 4 cannot be reached.
For operating the lock a key or key-card is held in front of the knob 2. The access control unit 8 receives the access signal. After detecting the authorized access signal an authorization signal is generated by the access control unit 8 and is transmitted to the control unit 11. The control unit 11 generates an electric signal upon which the electric motor drive 7 turns the eccentric 13. The eccentric 13 extends the rod 14 radially outwards. If the sleeve 15 of the locking pin 5 is aligned with a locking hole 6 of the socket 4 of the knob, the locking pin 5 engages the hole 6. The shaft can be turned by the knob.
If the sleeve 15 is not in an engaging position aligned with a recess or hole 6, the rod 14 is moved into the sleeve 15 and compresses the spring 16. The sleeve is now under compression with the effect that, upon turning the knob 5 until a locking hole 6 of the socket 4 of the knob 5 is opposite to the sleeve 15, the sleeve will be forced into the recess or hole 6. Then, the shaft 1 can be turned by the knob 5.
After this engagement the lock tappet 3 of the lock can be turned for opening or closing the lock. It may be provided that, after a predetermined time or after the operation of the lock, a signal is generated for moving the eccentric 13 and the rod 14 to its recessed or radially withdrawn position.