EP3404172B1 - Safety mechanism for locks - Google Patents

Description

The invention relates to a security device for locks with a handle, which is freely rotatable in the idle state and can be coupled to the locking member of the lock in the actuated state, a braking or blocking device being provided which, from a defined number of revolutions of the handle in a unit time, the further Rotational movement brakes or blocks.

Conventional locks can be actuated by means of a key, wherein by turning a key in a lock a corresponding locking lug is rotated, which moves a bolt into a closed position or withdraws it from a closed position into an open position. In electronic security systems, recognition logic and an electronic key in the form of cards or other identification media replace the key. After reading the electronic key, which corresponds to the mechanical scanning of a conventional key, the rotary movement of a handle, such as a knob or handle, is rotatably coupled via a corresponding coupling to a further rotatably mounted part, which subsequently actuates the bolt. In this context, electronic security systems have become known which are designed as double knob cylinders, elements of a detection logic, and in particular antennas or the like, being arranged on one side of the door to be opened, whereas the coupling of the rotary movement of this external rotatable part after detection of the correct key via electronics is usually done electrically by coupling a coupling element. In such devices, the external handle can be freely rotated without such a coupling. This freely rotatable handle is connected via a shaft to the opposite side of the door or window, on which the coupling is carried out with the actuator of the lock. The shaft is guided through the lock with relatively little play, whereby the free rotation with a relatively small play must be ensured without the risk of jamming and without the risk of an unintentional coupling. One possible training is, for example DE 19851308 A1 can be seen in which the locking cylinder is provided on both sides with knobs, of which the inside knob has an access control electronics. Depending on the identification of an identification medium, an access authorization is determined, with a clutch being actuated electromagnetically in such a way that a lock bit can be moved from the outside rotary knob.

Due to the small tolerances in the manufacture of such safety devices, it has now been shown that a possible improper manipulation is created by connecting a corresponding drive unit, for example an electric motor or spring motor, to the freely rotatable handle, which quickly handles the handle Rotation offset. With such a rapid rotation, a corresponding frictional heat is generated inside the lock, which, when the shaft rotates freely, can lead to rubbing or an unintentional coupling of an outer shaft with an inner shaft, so that despite the lack of electronic release of the clutch mechanically, a coupling achieved by thermal expansion or rubbing is created between the usual freely rotatable handle and the locking bit, whereby the lock can be operated. Such incorrect operation or sabotage operation, however, presupposes that the freely rotatable handle is limited to a minimum time appropriate minimum speed can be brought, which can lead to thermal expansion or rubbing.

In order to rule out such sabotage or incorrect operation and at the same time to ensure that the freely rotatable handle remains freely rotatable only at a relatively low rotational speed and counteracts rubbing or jamming in other cases WO 2007/095652 A1 A safety device of the type mentioned at the outset has already been proposed, in which at least one radially displaceable centrifugal weight is coupled to the handle, which engages with a fixed part of the lock in a unit of time after a defined number of revolutions of the handle and blocks the further rotary movement , The centrifugal lock ensures that the freely rotatable handle is immediately blocked if the speed is too high.

With a safety device of the in the WO 2007/095652 A1 However, the correct functioning cannot be guaranteed with certainty, especially in those cases in which a particularly high torque is applied to the handle. This is because there is a risk that the elements that can be displaced due to the centrifugal force will be mechanically overloaded and subsequently destroyed.

The invention therefore aims to improve a safety device of the type mentioned at the outset in such a way that the functionality is ensured even at very high rotational speeds and at high torques which are applied to the handle. The security device should function largely independently of the external forces acting on the lock.

To achieve this object, the invention provides in a safety device of the type mentioned at the outset that the braking or blocking device is designed as an eddy current brake. The eddy current brake here has in particular a magnetic element and an eddy current element, the magnetic element either having at least one permanent magnet or an electromagnet which is switched on when a certain speed of the handle is exceeded, as a result of which the eddy current brake applies a torque which is opposite to the torque of the handle.

The risk of tampering or incorrect operation described at the outset exists in particular in locks in which the handle is connected in a rotationally fixed manner to a coupling shaft passing through the lock, which can be coupled via a coupling to an actuating shaft which is connected in a rotationally fixed manner to the locking member of the lock, the Actuating shaft is designed as a hollow shaft, which is penetrated by the coupling shaft.

In a non-claimed embodiment, a safety device of the type mentioned at the outset, the braking or blocking device comprising an element which can be displaced between a release position and a braking or blocking position and which, in the braking or blocking position, interacts with a counter-element in order to further rotate to brake or block, it is provided that the handle is mechanically decoupled from the displaceable element in its release position. The mechanical decoupling ensures that external forces acting on the handle and the shaft possibly connected to the handle do not affect the part responsible for applying the braking torque or blocking, namely the displaceable element of the braking or blocking device can be transferred. Manipulation or damage due to violence is therefore excluded. The displaceable element is thus structurally separated from the handle or an element connected in a rotationally fixed manner to the handle, in particular in the release position, and in particular does not rotate with the handle. According to a preferred development, the displaceable element interacts only in the braking or blocking position with the handle or with a part that is coupled in a rotationally fixed manner to the handle in order to brake or block the further rotary movement.

This safety device includes versions in which the detection device for detecting the rotational speed of the handle is different from the braking or blocking device, in particular is mechanically decoupled. In contrast to the centrifugal weight brake described in the prior art, the braking or blocking device is therefore not subject to the geometric and material restrictions of the torque detection device and can therefore be designed to be more stable.

The mechanical decoupling of the rotary movement of the handle from the displaceable element is preferably achieved in that a drive for displacing the displaceable element between the release position and the braking or blocking position is provided, which is in motion by contactless, in particular magnetic coupling with the rotary movement of the handle is relocatable. The contactless coupling is preferably formed by an eddy current coupling driven by the rotary movement of the handle.

Alternatively, the contactless coupling can comprise an electrical generator which is driven by the rotary movement of the handle and which provides an electrical voltage for driving the displaceable element.

The eddy current coupling is particularly preferably designed in the manner of an eddy current tachometer. The eddy current clutch here preferably comprises an eddy current element and a permanent magnet element, which can be rotated relative to one another. In the case of an eddy current tachometer, the permanent magnet element provided with a permanent magnet rotates and generates eddy currents in the eddy current element which is arranged at a distance therefrom. The eddy current element preferably consists of a metal disc or bell made of an electrically conductive material, in particular aluminum. Due to the eddy currents in the eddy current element, an additional field energy is created. This field energy would be avoided if the rotatably mounted eddy current element were also rotated. This is prevented by a reset element. The magnetic field increases linearly with the speed, the field energy increases quadratically, the force effect as its derivation is linear again, as does the restoring force of the restoring element with its angular deflection. The deflection or the angle of rotation of the eddy current element is therefore proportional to the speed. The restoring element can preferably be designed as a spring element. Alternatively, any other element suitable for absorbing a torque or a force can be used as the restoring element. For example, the repulsion of two magnets with the same polarity could be used as resistance to the angular deflection.

In the construction of the eddy current tachometer described above, the permanent magnet element is coupled to the rotary movement of the handle and is thus driven by it. Alternatively, the eddy current tachometer can also be designed such that the eddy current element rotates with the handle is coupled. In this case, it is not the eddy current element, but the rotatably mounted permanent magnet element that is connected to the restoring element.

The angular deflection of the part of the eddy current tachometer connected to the restoring element is preferably translated via a gear or a conversion unit into a displacement movement of the displaceable element, so that the displaceable element is displaced from the release position into the braking or blocking position. In this case, the design is preferably such that the transmission or the conversion unit can shift the displaceable element from the release position into the braking or blocking position, regardless of the direction of rotation of the handle.

The transmission or the conversion element comprises, for example, a ramp formed on the part of the eddy current tachometer connected to the restoring element, which converts the angular deflection of this part into an axial and / or radial movement of the displaceable element. The displaceable element can in this case be guided in the axial and / or radial direction and can engage axially and / or radially with a part of the lock connected in a rotationally fixed manner to the handle and thereby block the further rotational movement of the handle.

A preferred embodiment provides that the eddy current element is designed as an eddy current disk made of ferromagnetic material. In certain circumstances, the use of a ferromagnetic material can increase the eddy currents.

In the case of an eddy current clutch or an eddy current tachometer, there is generally at least one permanent magnet on the permanent magnet element so arranged that both the one pole and the other pole of the magnet face the eddy current element. A preferred embodiment alternatively provides that the permanent magnet element has a first pole and a second pole, the first pole facing the eddy current element and the second pole facing away from the eddy current element. In such an embodiment, a magnetic circuit can close across the eddy current element. According to a preferred embodiment variant, this is further favored in that the eddy current clutch has a metallic, preferably ferromagnetic housing which forms a closed magnetic circuit with the first and the second pole of the permanent magnet element.

The invention is explained in more detail below on the basis of exemplary embodiments schematically illustrated in the drawing. In this show Fig. 1 1 shows a schematic overall view of a locking device according to the invention in a partially disassembled state with a safety device, Fig. 2 2 shows an enlarged illustration of the safety device in a first embodiment, Fig. 3 3 shows a detailed illustration of the eddy current element of the first embodiment, 4a and 4b Views of two variants of the permanent magnet element of the first embodiment and Fig. 5 an enlarged view of the safety device in a second embodiment.

In Fig. 1 1 denotes a knob, which is freely rotatable via a hollow shaft 2 and a coupling shaft 3 with an electromechanical clutch disc accommodated in a further knob 4. The clutch disc itself can be designed in any manner and can be coupled, for example magnetically or mechanically, to a corresponding component, for example the knob 4. The actuation shaft is designated 5 and is penetrated by a sliding sleeve 6. Furthermore, a locking lug 7 is provided for the actuation of the lock bolt, this locking lug 7 being kept adjusted in the axial direction by corresponding snap rings 8 and being non-rotatably connected to the actuating shaft 5, which itself is again non-rotatably connected to the inside knob 4 or after the coupling has taken place is rotatably connected to the clutch shaft 3.

Without a corresponding coupling of the actuating shaft 5 with the knob 1, the hollow shaft 2 and the coupling shaft 3 connected to it can be freely rotated. The coupling shaft 3 extends through the sliding sleeve 6 and rotates inside the same. In the event of sabotage, in which the knob 1 and thus the clutch shaft 3 are subjected to high torque and are rotated at speeds of 5,000-20,000 rpm, thermal expansion and rubbing can occur, so that the sliding sleeve 6 suddenly stops with the Coupling shaft 3 also rotates. Subsequently, due to the same effect, the actuating shaft 5 can also be carried along by the sliding sleeve 6, which can lead to actuation of the locking lug 7 in an undesirable manner.

In order to avoid the undesired actuation of the locking lug 7 described above, a safety device is arranged in the knob 4, which is coupled to the rotational movement of the coupling shaft 3 and whose further rotational movement brakes or blocks it from a defined rotational speed. The safety device at the in Fig. 2 illustrated first embodiment, a disc-shaped permanent magnet element 9, which is rotatably connected to the clutch shaft 3. The permanent magnet element 9 has at least one permanent magnet and interacts with an eddy current element 10, which is cup-shaped and surrounds the disk-shaped permanent magnet element 9 circumferentially. The permanent magnet element 9 and the eddy current element 10 together form an eddy current tachometer, wherein, as in FIG Fig. 3 It can be seen that the eddy current element 10 is connected to a retaining element designed as a spring 11, which exerts a restoring moment on the eddy current element 10 as soon as it starts from the position shown in FIG Fig. 3 shown rest position experiences an angular deflection. In this way, the angular deflection of the eddy current element 10 is directly proportional to the rotational speed of the permanent magnet element 9. The angular deflection of the eddy current element 10 is now translated via a suitable gear into a displacement movement of a displaceable element, not shown, so that the displaceable element from a release position into a braking or Blocking position is shifted. In the braking or blocking position, the displaceable element engages in a recess in the coupling shaft 3 or interacts in another way with the coupling shaft 3 or with a component connected in a rotationally fixed manner in order to exert a braking torque or a blocking effect on the coupling shaft 3 or the knob 1 ,

Fig. 4a shows a view of the end face of the permanent magnet element 9, the permanent magnet of which has a first magnetic pole (north pole) 15 and a second magnetic pole (south pole) 16, both of which face the eddy current element 10. When training according to Fig. 4b the end face facing the eddy current element 10 is divided into four, two south poles 16 and two north poles 15 being provided, which are arranged alternately in the circumferential direction. Further modifications are conceivable in which the end face is divided into 6, 8, 10 etc. parts.

In Fig. 5 A modified embodiment of the safety device is shown, in which the eddy current tachometer is enclosed by a ferromagnetic housing 12. The eddy current element 10 is also made of a ferromagnetic material. Furthermore, a permanent magnet is arranged on the permanent magnet element 9 such that one magnetic pole 13 of the permanent magnet faces the eddy current element 10 and the other magnetic pole 14 of the permanent magnet faces away from the eddy current element 10. This closes a magnetic circuit via the housing 12.

In principle, the invention is not restricted to certain designs of locking devices. Thus, the security device according to the invention can be used not only in cylinder locks, but also, for example, in fittings which have the function of coupling or uncoupling the handle from the door latch actuation. In the decoupled state, the handle, e.g. a handle without effect, while the handle operates the latch when coupled. In the uncoupled state, the safety device according to the invention is used and is intended to prevent a jerky actuation of the handle without access authorization from actuating the latch.

Claims (3)

1. Security device for locks with a handle, which can be freely rotated in the idle state and can be coupled to the locking member (7) of the lock in the actuated state, wherein a braking or blocking device is provided, which, starting from a defined number of revolutions of the handle per time unit, brakes or blocks the further rotary movement, characterized in that the braking or blocking device is designed as an eddy current brake.
2. Security device according to claim 1, characterized in that the handle (1) is connected in a rotationally fixed manner to a coupling shaft (3) penetrating the lock, which can be coupled via a coupling to an actuating shaft (5), which is connected in a rotationally fixed manner to the locking member (7) of the lock, wherein the actuating shaft (5) is designed as a hollow shaft, which is penetrated by the coupling shaft (3).
3. Locking device for building doors, preferably lock cylinder or fitting, window or the like, comprising a handle, which can be freely rotated in the idle state and can be coupled to the locking member of the locking device in the actuating state, characterized by a security device according to any one of claims 1 or 2.

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