WO2008057024A1

WO2008057024A1 - Key

Info

Publication number: WO2008057024A1
Application number: PCT/SE2007/000990
Authority: WO
Inventors: Carlos De La Fe Dahlin
Original assignee: Carlos De La Fe Dahlin
Priority date: 2006-11-10
Filing date: 2007-11-09
Publication date: 2008-05-15
Also published as: EP2079893A1; SE530564C2; SE0602398L

Abstract

The present invention relates to a key (1), to the head of which is attached a device (7). Said device comprises an accelerometer (13), which detects the movements made by the key as it is used to lock and unlock a door. After detecting said movements, the device saves information about whether the movements were made in connection with locking or unlocking. This information is presented, for example on a display. The invention thus makes it possible for the key bearer to find out whether the key when last used was used to lock or unlock the lock.

Description

KEY

Technical field of the invention

The present invention relates to a key. After leaving home, many people start to worry about whether they did in fact lock their door. This may cause discomfort. The object of the present invention is to remedy this. It should be noted, that the word key also covers key blank. A key blank is a key not yet machined to fit a particular lock. The key shown in Fig. HA, for example, is machined by grinding teeth from the blank. In this case, the inventive technology is attached to the blank.

Prior art Within the patent class E05B19/22, there are known devices relating to keys, designed to indicate whether the last operation of a key, see Fig. 1, was locking or unlocking.

Objects and features of the invention A primary object of the present invention is to provide a guick answer to the question put by a person having left his home, whether he in fact locked his front door (5), by briefly checking the key (1) (or in particular, by checking the device (7) on the key head) . The inventive concept is based on registering the movements of the key (1), and to retain in a memory (14) the type of operation (locking/unlocking) registered in connection with a movement that is characteristic of the operation. Below, the expression "characteristic movement" signifies a movement made by the key in connection with the operation. Hence, a key operation is connected with a "characteristic movement". It should be noted, that by a key operation is meant locking or unlocking, i.e. the type of operation is either "locking" or "unlocking". The type of operation is indicated to the key bearer when he wants to find out whether the key was last used to lock or to unlock the door. It might also be possible to retain and present information about the point in time when the latest key operation took place. This might be useful in order to tell the user how long ago the key was used. Information about the time of use may be obtained from a clock indicating that point in time, or by starting a timer at that point in time.

Description of the drawings

Below, a number of embodiments of the invention will be described, with reference to the accompanying drawings, of which:

Fig. 1 shows two common types of keys;

Fig. 2 shows the keys inserted in a door (5) . The arrows indicate the circular movement made by many keys in connection with locking/unlocking; Fig. 3 shows a key inserted in a door (5); the arrow indicates another possible movement of a key (different from that shown in Fig. 2) in connection with locking/unlocking;

Fig. 4 shows the device (7) attached to the head of the key; Fig. 5 shows the device (7). The device comprises a display area (9), where a symbol, in the figure represented by a padlock, indicates whether the key (1) when last used in a lock was used to lock or to unlock the door. The display (9) as shown also indicates the point of time when the key (1) was last used;

Fig. 6 shows the device (7) provided with two pins (10), adjustable to different lengths. In the device illustrated, one pin is fully retracted and the other is extended. The indicated position of the pins might for example indicate "locked" and a position where both pins are retracted might indicate "unlocked"; Fig. 7 shows the device (7) provided with a loudspeaker membrane (11) ;

Fig. 8 shows the device (7) provided with a vibrator (12); Fig. 9 shows an accelerometer (13) with two axes (15, 16).

It should be noted, that most figures do not indicate the number of axes of the accelerometer. When subject to acceleration, the accelerometer (13) registers the vector components of the acceleration in the directions of the axes. Fig. 10 shows the key (1) in an end view when inserted in a door (5) . The key is shown as turned to an angle (19) from the gravitational vector (18) . Two of the axes of the accelerometer, x and y (15, 16) , are indicated in the figure. The accelerometer shown is attached to the device (7) in such a way that two of its axes (15, 16) lie in the vertical plane defined by the door (5) , one axis (16) being parallel to the gravitational vector when the angle (19) is zero. The figure also shows the vector components gx and gy, which are parallel to the axes of the accelerometer, and the vectorial sum of which is equal to the vector g (18) .

Fig. 11A is a side view of the key (1) when it is partly inserted in the door (5) . The arrow directed to the right indicates that the key is being pushed into the lock, which causes vibrations. Fig. HB is an end view of the key according to Fig. HA, showing also the gravitational acceleration acting on the key;

Fig. HC is a side view of the key according to Fig. HA, the key having been pushed further into the lock; and Fig. 12 shows an electromagnetic arrangement. An electric current runs through the lower coil (28), creating a magnetic field, which attracts the lower pin (10) .

Description of a first preferred embodiment Fig. 4 shows a device (7), primarily designed to fit on a key head (1) (the drawing shows two variants, the only difference being that they are adapted to two different types of keys) .

The device (7) comprises an accelerometer (13), a display (9), a memory (14), a processing unit (27), a battery to power the system (not indicated in the drawings) , and a clock (not indicated in the drawings) . The device (7) is a system comprising the said components. The device registers and interprets the signals provided by the accelerometer (13), and when a movement occurs which is characteristic of a key operation, the type of operation is retained in the memory (14). The defined types of operation are "locking" and "unlocking". When the type of operation is retained in the memory, the time of occurrence is also saved (alternatively, a timer is started), to indicate when the operation took place. Immediately after registering the operation, or when prompted by the bearer of the key, for example by pressing a pressure sensitive area, such as a button, on the device (7), a symbol is displayed. In Figs. 4, 5 and 12, that symbol is a locked padlock. The symbol indicates the latest type of operation registered. In the display area (9) an indication might also be made of the point in time when the latest operation was registered (or the length of time passed since that operation) .

Description of a second preferred embodiment:

This embodiment is identical to the first one, the only difference being in the presentation of the information about latest type of operation and the point of time of said operation:

Fig. 6 shows the device (7) . In this embodiment, the device is provided with two pegs/pins (10), which can be extended or retracted independently of one another. Fig. 6 shows the device with one of the pins (10) retracted and the other extended. The position of the pins is used to provide information about whether the latest operation was locking or unlocking. Both pins extended could for example be indicative of "locking", and only one pin extended could mean "unlocking" .

The pins could for example be made to move inwards or outwards by means of an electromagnetic arrangement, see Fig. 12. This arrangement comprises, in accordance with the drawing, two iron cores (28) that generate an electromagnetic force when current passes through the respective coils (29) , said force pulling the respective pin (10) inwards. The drawing shows that tension springs (30) are attached to the pins (10), keeping them extended in the absence of magnetic forces .

The advantage of presenting information this way is that the key bearer can quickly ascertain, for example by putting his hand in his key pocket and using a finger to feel the pins (10) , whether the key (1) was last used to lock or to unlock the door (5) . The basic principle in this embodiment is to modify the geometry of the device in such a way that the modification can be felt by touch, for example using a fingertip. The illustrated embodiment is just an example of how the said geometry may be modified. For example, an arbitrary number of pins may be used, a part of the surface may be displaced, or the surface structure modified. The modification in itself could be made to carry information about the amount of time passed since the key was used. For example, Braille lettering, or simply the length of the pins, could be used to indicate the length of time passed since the key was used.

The device (7) could, for example, be coated with a flexible rubber surface, which expands when pins or suchlike are extended from within.

Description of a third preferred embodiment

This embodiment is identical to the first one, the only difference being in the presentation of the information about the latest type of operation and the point of time of said operation.

Fig. 7 shows the device 7. The device is provided with a loudspeaker membrane 11. The loudspeaker membrane is used to create sound; a high-pitched note might mean locked, and a low-pitched note unlocked. Another example of sound is a voice being played, telling the key bearer the latest type of key operation, and when that operation took place. The sound would preferably be played on a demand from the key bearer, for example by pressing a button or pronouncing some sound that the device can identify. Description of a fourth preferred embodiment

Fig. 8 shows the device 7. The device is provided with a vibrator 12. The vibrator is used to issue a vibration. A particular vibration, such as one of low frequency, can be used to indicate unlocked, and another, such as one of high frequency, can indicate locked. The vibration may be invoked by the key bearer for example by pressing a button, pronouncing a certain sound being identifiable by the device, or hitting the key mechanically, so that the device, via the accelerometer, identifies the induced vibration of the key.

The characteristic movement in general

As an example, without limitation, the characteristic movement of a particular operation generally, for a specific and common type of key, corresponds to a circular movement in a vertical plane, which the key carries out when locking/unlocking, according to the arrows displayed in Fig. 2. Depending on the type of lock, an anticlockwise movement corresponds to locking or unlocking, and a clockwise movement will correspond to the opposite. As another example, without limitation, the key to some locks is turned as indicated by the arrow in Fig. 3.

Even if the device (7) is attached to the head of a key (1), which is intended to be used in a lock where a particular characteristic movement is used for locking/unlocking, it may be advantageous to let the device (7) be capable of registering many different characteristic movements, typical of various types of locks. Such a capability would eliminate the need to adapt the system to the particular lock where the key in question is used. However, it may be preferable to adapt the device to the particular lock, for example to reduce the demand for processing power when the accelerometer (13) registers the characteristic movement for that particular lock. Such an adaptation may be made when manufacturing the device, or possibly by the key owner, who is prompted to configure the key before starting to use it in the intended lock.

Alternatively, each device may be given a period of learning, during which the key bearer indicates to the device that the movement carried out was in fact a locking movement, and correspondingly when unlocking, until the system has learnt to identify the characteristic movement. A learning system may be preferable, if it turns out that the characteristic movement is difficult to identify, or can be described only by saying that it is contained within, for example, a torus, but cannot be described more specifically, because the movement varies from one time of use to another. It should be noted that the system is designed to make the probability extremely small that a characteristic movement will take place inadvertently, such as in the key bearer's pocket .

Registering a characteristic movement by detecting the components of the gravitational vector

One way of registering the movements of the key (1), in particular its characteristic movements, by means of the accelerometer (13) , is to detect the components (20, 21) of the gravitational vector (18) along the axes (15, 16) of the accelerometer, see Fig. 10. The sizes of these components indicate the orientation of the key, and consequently, their changes indicate how the key is turned. It should be noted, that the absolute value of the gravitational vector g (18) is IgI =9.81 m/s², and that the vector g is directed towards the centre of the earth.

If the accelerometer (13) has two axes, and it is attached to the device in such a way that its axes x and y (15, 16) lie in the vertical plane of the door (a normal door) when the key is fully inserted in the lock, the following equations apply (assuming that the axes in question are orthogonal) :

1. IgI² = |gx|² + |gy|² 2 . | g | sin (v) = | gx |

3. | g | cos (v) = l gy l

Here, |gx| and |gy| are the absolute values of the vectors gx (20) and gy (21), i.e. the components of g along the x and y axes of the accelerometer, respectively, see Fig. 10.

In the equations above, v (19) is the turning angle i&f the key in relation to g, i.e. the angle between the vector gy (21) and the vector g according to Fig. 10. The signals obtained from the accelerometer can be used to compute | gx | "and lgyl. The angle v (19) can be computed using the equations 2 and 3. The defining property of the characteristic movement in this case is that v changes in a characteristic way while satisfying equation 1. As soon as the processor (27) notes that equation 1 is satisfied, signifying that the key may ^"have ^• been inserted into a lock, it starts to examine if the change in v (19) corresponds to the characteristic turning movement of a key operation. If this is the case, equation 1 being satisfied during the whole movement, the type of operation is retained in the memory (14) of the device, together with a point in time. In this case, the direction of turning (clockwise/anticlockwise) indicates the type of operation.

It should be noted, that the above process is only an example of how the accelerometer can detect the characteristic movement of a particular operation. It should also be noted, that the acceleration being measured is in fact the sum of all accelerations influencing the accelerometer. In the above description, it has been assumed that the vector g is so large that any other prevalent acceleration can be disregarded.

However, it may be noteworthy, that unless the accelerometer is placed in the exact centre of rotation when the key is turned in the lock, the accelerometer will be subjected to centripetal acceleration. Registering a characteristic movement by registering vibrations

Another way of identifying the characteristic movement of a key with teeth (22), see Fig. 11, is the following: An accelerometer having one axis is fitted to the device (7) in such a way that when the key (1) has been inserted into the lock but has not been turned, the accelerometer axis (26) is directed at 45 degrees (23) from the perpendicular to the vertical plane defined by the door, and at 45 degrees (24) from the vertical plane defined by the key head. It should be noted, that the number 45 may be replaced with any other number not equal to 0, nor equal to any multiple of 90, but 45 is a useful choice. Fig. HA shows a key being inserted into a lock. When this happens, vibrations occur with an extension along the key, as indicated by the arrow in Fig. HA. These vibrations are a result of the fact that the key has teeth (22) . In Fig. HA, these vibrations are symbolized by a vector a. In Fig. HA, the vector g is omitted. Fig. HA shows the vector I ax I , which is the component of the vector a along the axis (26) of the accelerometer. Figs. HB and HC show the key as seen from behind and from the side, respectively.

The characteristic movement comprises three elements:

1. First, the key is inserted into the lock, causing the characteristic vibrations, i.e. variations in |ax|, see Fig. HA.

2. When the key operation then takes place, the angle v (24) changes, see Fig. HB, in a way that is characteristic of the type of operation (unlocking or locking) . For a lock of a type, see Fig. HB, where locking is done by turning the key (1) anticlockwise a full turn, the full turn corresponds to 45°≤v<405°. In this particular case, the characteristic change in v when the key locks the door is that v increases from v=45° to v=405°. When the key is used to unlock the door, the same change takes place, but in the other direction.

3. When the key after being turned is pulled out of the lock, characteristic vibrations occur, i.e. |ax| changes. After having registered these three elements, the processor (13) will save the type of operation, possibly together with an indication of the point in time; alternatively, a timer is started.

It should be noted, that the above process is only an example of how the accelerometer can detect the characteristic movement of a particular operation.

Claims

1. Key (1), c h a r a c t e r i z e d in that a device (7) is attached to the head of the key (1), that said device (7) constitutes a system, comprising at least one accelerometer (13), at least one processing unit (27) and at least one memory (14), that said device (7) detects the movements of the key by means of said accelerometer (13) , and that said device (7), on detecting a characteristic movement, saves information about the corresponding operation in said memory.

2. Key (1) according to claim 1, c h a r a c t e r i z e d in that said device (7) comprises a clock, which registers the point in time when said operation is carried out, and that the device (7) saves this point in time in said memory (14) .

3. Key (1) according to claim 1, c h a r a c t e r i z e d in that said device (7) comprises a timer, which can be started when said operation is carried out.

4. Key (1) according to any of the previous claims, c h a r a c t e r i z e d in that said device comprises means

(8) for presenting the information saved in said memory (14) .

5. Key (1) according to claim 3, c h a r a c t e r i z e d in that said device comprises means (8) for presenting the information saved in said memory (14) together with the length of time passed since said operation took place, as indicated by said timer.

6. Key (1) according to claim 4 or 5, c h a r a c t e r i z e d in that said means (8) comprises a graphics display area (9).

7. Key (1) according to claim 4 or 5, c h a r a c t e r i z e d in that said means (8) comprises an area (10) on the outer surface of said device (7), capable of changing its geometry.

8. Key (1) according to claim 4 or 5, c h a r a c t e r i z e d in that said means (8) comprises a sound generating body (11).

9. Key (1) according to claim 4 or 5, c h a r a c t e r i z e d in that said means (8) comprises a vibrator (12) .

10. Key (1) according to any of the previous claims, c h a r a c t e r i z e d in that said device (7) detects the movements of the key (1) by at least measuring the components of the gravitational vector (18) in the direction/s of the axis/axes (15, 16) of said accelerometer (13).

11. Key (1) according to any of the previous claims, c h a r a c t e r i z e d in that said device (7) detects the movements of the key (1) by at least measuring the vibrations created when the key (1) is inserted into/pulled out of a door (5) .