KEY BOX Technical Field

The present invention relates to a key box for safe handling of keys, and a method performed by the key box.

Technical Background In cases when a professional, such as a caretaker or a security guard on a round or beat, need to achieve access to several restricted areas some sort of access control needs to be overcome. This access control may consist of physical keys, codes on key pads etc. The former case is highly relevant for caretakers visiting persons receiving care, since most people still have doors with using regular physical keys. For a caretaker performing several persons every day, the administration around safe handling of keys is cumbersome, and the security is always an issue.

WO 04/018804 discloses a method and a device for safe handling of keys. The device aiming at providing an electronic method for safe handling of a key, in which a casing is fixed to an object having an accessible side, a lockable body is arranged to be moveable between an open position and a closed and lockable position inside said casing, by an electrically/electronically controlled locking device, for safekeeping a key inside said casing such that said key is non-obtainable from the accessible side of the object when the lockable body is in its closed position but only obtainable from the accessible side of the object when said body is in the open position. The lockable body is arranged to be displaccable inside said casing and the said locking device is placed to be inaccessible from the accessible side of the object, in one or more embodiments this is exemplified by the casing being a cylindrical insert attached to the object, and by the lockable body is a hollow cylinder in which the key may be positioned.

In the above application problems with traditional ways of handling keys and benefits with an electronic method are discussed.

The device and method described above is functional, still there is room for improvement, particularly in terms of power consumption.

Summary The present invention provides a key box eliminating the problems mentioned in relation to prior art. The inventive key box is particularly well-suited for retrofit to a

specific location, since the very low power consumption is ideal for a battery powered device. Further advantages will be described in the following detailed description of preferred embodiments.

To this end the present invention provides an electronic device for safe handling of a key, adapted for arrangement at a structure with an accessible side and a side with limited access. The device comprises a mounting clement mounted to the structure, in a direction from the accessible side towards the side with limited access, a lockable body insertable in the mounting element; a control unit; and a lock mechanism arranged on the side of the structure with limited access. The lock mechanism operably cooperates with the lockable body via a lock element when the lockable body is inserted in the mounting element, said lock element being movable in a locking direction and an unlocking direction, wherein the control unit is adapted to control the lock mechanism to unlock the lockable body based on an external input. The device comprises a motor having a rotatablc drive shaft, which is controlled using the control unit, for moving the lock element into, and out of, engagement with the lockable body.

The advantages of having a non-accessible lock mechanism are obvious from a security standpoint. Further, since the lock mechanism generally will not be subjected to rain, dew, dust and other natural phenomena, its function will be reliable. The use of a motor with a rotatable driveshaft makes it possible for the device to rest in a locked or unlocked state without consuming any power, which is obviously is beneficial for the inventive purposes. That the control unit and the lock mechanism are arranged on the side with limited access effectively means that they are non-accessible from the accessible side. An example would be that the device is arranged in a door to a restricted area, and that the control unit and the lock mechanism are arranged on the inside. One advantage of using an electrical motor instead of a pulling electromagnet is that the latter consumes more power, and requires higher peak currents, which in turn results in the necessity of using more powerful, and expensive, batteries.

In one or more embodiments the driveshaft is operatively coupled to the lock element via at least one eccentric cam element. An eccentric cam element provides an efficient coupling in order to transform the rotational motion of the driveshaft to a lateral movement of the lock element. The frictional losses may be reduced as compared to a geared solution, yet the eccentric cam is reliable and rugged.

The cam element may further be in operative contact with the lock element in two contact positions, one in the opening direction and one in the closing direction. The

operative contact makes the control of the device direct and reliable. Further, the control may be performed with high precision.

The friction in a contact point between the cam element and the lock element in structurally reduced. The structural reduction of friction may be performed in several ways, all with the main purpose of reducing the power consumption. Examples include natural low-friction materials, such as TPFE, in components abutting each other in the contact point; roll bearings, ball bearings etc arranged on one or both of the components being contacted.

In one or more embodiments the contact point provided in the locking direction may be provided on a spring-biased element, biasing the lock element in the locking direction. The spring-biased element will, as evident, bias the lock element in the locking direction. In effect, this also allows for a high-precision contact, at the same time as the lock element will be free to move by another cause than the rotation of the eccentric cam element. For example, this makes it possible for the lock clement to remain in the locked position when the lockable body is inserted. Further, it will be possible to manipulate the lock element manually from the side of the structure with restricted access, as will be discussed later on.

The spring-biased element may in one or more embodiments comprise a leaf spring, operatively attached to the lock element. The leaf spring provides a rugged solution with few movable parts providing the desired biasing function. Since the spring is attached to the lock element it will move with the latter. This effectively means that during movement of the lock element the motor does not have to work against the resilient force of the spring, since it will follow the lock element automatically.

In one or more embodiments the frictional reduction may be performed by designing the cam element as a cam roll, comprising a roll or ball bearing decoupling the inner circumference of the cam element from the outer circumference. This construction is a simple and reliable way of reducing the friction.

Further, two cam rolls may be arranged on the drive shaft; a first contacting the lock element in the opening direction, and a second contacting the lock element in the closing direction. This construction makes it possible to decouple the movements and reduce friction to an absolute minimum.

In order to provide a direct and reliable lock element it may be formed in one piece by a stamped plate of sheet metal and wherein the portion of the lock element engaging a recess in the lockable body comprises an area being bent in a direction away from the accessible side of the structure. The bent portion cooperates with the lockable

body, such that it would require a considerable effort to pry the lockable body open. Combined with that the lockable body is difficult to grasp with a tool from the outside this provides an efficient safeguard from unauthorized access

An inventive method for operating the device may comprise the steps of: - activating of the device authenticating the user by means of wireless communication with a user carried unit, such as a mobile phone operating the lock mechanism to assume an unlocked position and release the lockable body. The activation step is generally necessary since the device may incorporate the feature of having a stand-by mode, in which it simply awaits a "wakc-up call", which could be effected by a knock on the structure in which the device is mounted. The knock may be detected by a vibration sensor.

In one or more embodiments the control unit determines that the unlocked position is reached by means of monitoring the current consumed by the motor, which is an efficient way of determining the position of the lock element.

The lock mechanism may be operated to assume the locked position based on the determination that the unlocked position has been reached or that the lockable body has been reinserted in the mounting element. In the presently most preferred embodiment the lock mechanism returns to the locked state after the unlocked position has been reached. Once the unlocked position is reached the lockable body will be ejected, and thanks to the spring-biased lock element it is possible to reinsert the lockable body without unlocking the lock element actively.

Brief Description of the Drawings

Fig. 1 is an exploded isometric view of a key box according to a first embodiment of the present invention.

Fig. 2 is a detailed exploded isometric view of components comprised in the lock mechanism is a device according to the first embodiment of the present invention. Fig. 3 is a cross section of the device according to the first embodiment in a mounted state.

Fig. 4 is a detailed cross sectional view of part of Fig. 3 illustrating the cooperation between the lockable body and the lock element of the first embodiment of the present invention, showing an example of the design of the lock element. Fig. 5 illustrates the inventive method according to a first embodiment.

Fig. 6 is a detailed view illustrating the function of a stop lug and slop pin used in one embodiment of the present invention.

Description of Embodiments Fig. 1 is an exploded isometric view of an electronic device for safe handling of keys, according to the first embodiment of the invention, in the form of a key box. Starting from the left the key box 1 comprises a key tube 2, which is a lockable body in which there is a compartment 4 for the key to be stored. The key tube 2 has a tapered end portion 4 to facilitate insertion into the mounting tube 8 and the tapered end portion 4 terminates, at its portion remote from the end of the key tube 2, with a circumferential recess 6 in the form of a step towards the center of the key tube 2. The recess 6 is adapted io cooperate with a lock slide, to be described.

The mounting tube 8 has an essentially cylindrical outer shape, which facilitates the arrangement of a hole in the structure through which the mounting tube 8 is to extend. The inner through hole of the mounting tube 8 has a shape allowing the insertion of the key tube 2. When inserted in the mounting tube 8 the end of the key tube 2 visible from the accessible side of the structure (i.e. the end remote to the tapered end portion) is flush with the corresponding end of the mounting tube 8, or at least not extending beyond it. This, together with the tight fit of the key lube 2 inside the mounting tube 8 makes it difficult to grasp the key tube 2 with a tool. The same end of the mounting tube 8 is provided with a circumferential flange 10, which prevents the mounting tube 8 from entering the hole made in the structure. After insertion of the mounting tube 8, the flange will abut the accessible side of the structure and the mounting tube 8 will be secured to the structure by means of nuts 12, 14 arranged on threads 16 on an outer periphery of the mounting tube 8, on the non-accessible side of the structure. A mounting piece 15 is arranged between the structure and the nuts 12, 14, for facilitating the subsequent mounting of components.

A biasing spring 17 is arranged to bias the key tube 2 towards the accessible side of the structure, such that if the key tube 2 is released, it will be ejected in this direction. On the non-accessible side of the structure the tapered end portion 4 projects, when inserted in the mounting tube 8, through the structure, and is fixed by an angled flange portion 18 of a lock element in the form of a lock slide 20. The lock slide 20 is arranged to slide in a direction essentially perpendicular to the insertion direction (the length axis of the key tube 2 and the mounting tube 8), and is biased by a leaf spring 22 in a locking direction, towards a locking position in which the flange 18 of the lock

slide 20 cooperates with the recess 6 of the key tube 2. In this embodiment the lock slide 20 is a piece of profiled sheet metal, and the flange portion 18 is formed from the same piece of metal as the rest of the lock slide 20 and is bent in the insertion direction of the key tube 2 (away from the accessible side of the structure). This particular shape makes it difficult to pry the key tube 2 open, since the actual key tube 2 will prevent the flange portion 18 from bending in an opening direction, which is described in more detail later, referring to Fig. 3. The lock slide 20 has a hole 24, which will permit insertion of e.g. a screwdriver in order to allow for the lock to be opened from inside in case of power failure or other error. Further, and more importantly, this gives the person having access to the side of the structure with restricted access the possibility to dispose of the key according to his or hers wishes, without the need to obtain any particular authorization. If the hole 24, or another mechanism coupled to the lock slide, is used to pry the lock open the leaf spring 22 will bias the lock slide 20 back towards its original position. The hole 24 could obviously be replaced by a more complex construction, e.g. a lever (not shown) with a release mechanism such that it does not induce any considerable friction during normal operation of the device.

A motor mount 26 and a motor 28 are mounted to the mounting piece 15. The motor is an electrical DC motor, preferably a brushless motor. The motor drive shaft 32, see Fig. 2, extends directly or indirectly via the guide pin 37, to a shaft support (not shown), which prevents it from bending or flexing under load. In a simple embodiment the shaft support may be designed as an opening in the lock casing 39. On the drive shaft 32 two cam rolls 34 and 36, respectively, are arranged. The cam rolls 34 and 36 basically consist of cylindrical roll bearings arranged on a central cylindrical piece 35 with an offset through hole for the drive shaft 32. The cam rolls 34, 36 will thus be eccentrically arranged on the shaft 32. A guide pin 37 extends coaxially with the driveshaft 32, as apparent from Fig. 3. Also shown in Fig. 1 is a circuit board 35, comprising the control unit and associated circuitry.

The cooperation between the cam rolls 34, 36, the lock slide 20 and the leaf spring 22 is important for the function of the inventive concept and will be described in more detail referring to Figs. 2-4. It should be noted that the function of these components could be accomplished with another set of components, e.g. the leaf spring 22 could be replaced with a plate suspended with regular coil springs etc. Further, inventive concept should not be limited to the exact construction of the lock slide 20, since other means to transfer the rotational movement of the drive shaft 32 in order to unlock the device are possible. Having said this, it should also be emphasized that the

present embodiment provides a simple and rugged solution fulfilling the objects of the invention.

The relation between the components coupled to the motor is described in more detail referring to Figs. 2 and 3, which is an exploded view illustrating the motor 28, Che motor mount 26, and the drive shaft 32 onto which the cam rolls 34, 36 are arranged, and a cross sectional view, respectively. Also, the central cylindrical piece 35 is shown. The outer cam roll 36 abuts, with its roll bearing, the leaf spring 22 and the inner cam roll abuts, with its roll bearing, the lock slide 20. This arrangement greatly reduces frictional losses, since there will be no sliding movement between the roll bearings and corresponding abutment surface. Further, the leaf spring 22 is operably connected to the lock slide 20, in the slots illustrated in Fig. 1 , and serves two main purposes. The first has already been mentioned; to bias the lock slide towards its original position if the lock slide 20 is opened by using the hole 24, or when the key tube 2 is inserted into the mounting tube 8 and the lock slide 20 is in a locked position, in fact, this is basically the only situation in which the biasing action of the spring 22 is used. The second purpose is the hold the lock slide 20 in contact with the eccentric cam rolls 34, 36. If only the latter purpose was to be achieved, i.e. if the security function provided by the hole was solved by other means the leaf spring 22 could be removed, and replaced with an opening 27 fitting more tightly to the cam rolls 34, 36. In relation to the present embodiment it must be emphasized that as the drive shaft 32 of the motor 28 rotates it does not have the overcome any biasing force of the leaf spring 22, it only has to provide the power needed to move the lock slide 20 between the locked and unlocked state, since the leaf spring 22 is attached to the lock slide 20. The movement of the lock slide 20 between its end positions (locked state ■■•- unlocked state) is performed with high precision, with reliable components, and the distance traveled may be reduced to an absolute minimum, which also reduces the power consumption and reliability of the lock function. By operating the motor 28 to turn the drive shaft 32 it is possible to push the lock slide 20 upwards and unlock the key tube 2.

When not in immediate operation the control unit sets the device in a power saving standby mode, in which essentially no power is consumed. When a user want to access the key in the key tube 2 the device is activated by means of a knock on the structure in relation to which the device is arranged. Once activated the control unit will authenticate the user and, if the user is authorized to access the key tube 2, unlock the key tube 2 by activating the motor 28 controlling the lock mechanism. The technique associated with this is thoroughly described in WO2006/098690, which is incorporated

by reference, and it will not be discussed in detail here. To that end the device may have: means for short-range wireless data communication device in compliance with a communication standard, preferably Bluetooth ^{I M} ; means for detecting a key device, such as a mobile phone, within operative range of the lock device; means for determining a wireless communication address of the key device; a data storage with a number of wireless communication addresses stored therein; means for evaluating the determined key device address by referring to the number of wireless communication addresses stored in the data storage and generating an evaluation result, wherein a match between the determined key device address and any of the wireless communication addresses stored in the data storage is a requisite for a positive evaluation result; and means for unlocking said lock if a positive evaluation result is generated. Once activated the driveshafl 30 will be operated to rotate and thus lift the lock slide 20, by means of the mechanism described above. During the lift the current consumption is monitored, and when it is determined that the lift is effected the rotation of the driveshaft 30 is reversed, and it is rotated back to its original position. Optionally a stop pin 31 is arranged in connection to the driveshaft 30. As the driveshaft 30 reaches an end position (locked or unlocked) the pin 31 will interact with a stop lug 33 (in Fig. 6), which results in a readily detectable increase in current consumption. The technique for monitoring current with the purpose of detecting the position of a locking element is disclosed in the copending application PCT/EP2008/052008, hereby incorporated by reference. The stop lug 33 will in the locked position also prevent the lock slide 20 from inadvertently assuming an unlocked position, which is explained below. There are obviously other techniques for monitoring the position of the lock slide 20, such as micro switches etc. The stop lug 33 may as mentioned also serve the purpose of, in the locked position, preventing the motor from rotating towards the open position. This may be assured by having the cams positioned in such a way, in the locked position, that a force trying to unlock the lock will rotate the cams such that the pin 31 is forced towards the stop lug, and inadvertent unlocking of the lock is prevented. After performing the above steps the key tube 2 has been released and ejected, by means of the spring 17, and the lock mechanism has returned to a locked state, ready for the insertion of the key tube 2. As the key tube 2 is reinserted in the mounting tube 8 its tapered end portion 4 will force the lock slide 20 upwards, and once fully inserted the

key tube 2 will be engaged by the flange portion 18 of the lock slide 20. The bent flange portion 18 will reduce the friction between the lock slide 20 and the key tube 2. Further, the circumferential recess 6 is slightly undercut, such that it will cooperated with the flange portion of the lock slide 20 to pull the latter in the locking direction. In absence of a leaf spring 22 or similar flexible, biasing arrangement a the control unit could arrange for the lock slide 20 to remain in the unlocked position until the key lube 2 is reinserted (which could be determined by means of an electronic switch, or other means obvious for the skilled person), and then return to the locked position. Fig. 3 illustrates a device according to the first embodiment of the invention, mounted to a structure, in the form of a door blade 40. Many components have been discussed earlier, and to facilitate understanding of the drawing some more are mentioned in the list below, but not discussed any further.

In the inventive device of the described embodiment the motor and its shaft is mounted in the same direction as the key tube, i.e. perpendicular to the structure where it is mounted. To reduce the lateral extension of the device it would be possible to mount the motor parallel to the structure instead, in which case a suitable gear arrangement would be arranged to transfer rotation from the drive shaft to the cam rolls.