FR2791726A1 - Controlled access contactless lock, for car or building, has antenna loop ferrite section with protruding portion mounted and having outer cover - Google Patents

Abstract

The contactless electronic lock has an antenna loop (31) mounted on a ferrite section (32). The ferrite section has a protruding unit. The unit is protected by a cover (38). The whole unit fits in a key hole with an electronics box behind it.

Description

LECTRONIC LOCK WITHOUT CONTACT

  The present invention relates to a contactless electronic lock particularly suitable for controlling access to places to be protected, such as buildings, but also by

  example of vehicles. For the sake of simplicity, we limit ourselves

  terons in the case of buildings. Such a lock includes an antenna capable of emitting a magnetic field and of detecting in return a signal generated by a contactless key, generally a card the same size as a credit card and containing a conductive loop connected to a programmed chip. and identifiable. The contactless key can also be in the form of a key ring,

a key, a watch ...

  Today, access to many buildings is via conventional keys, each tenant of which has a copy, as well as outside parties such as letter carriers, technicians from electricity companies or maintenance of various installations. This system has a very limited level of security because the multiplicity of existing passes and the relative ease to force these locks make

  intruders manage to break into the buildings.

  To improve security, systems use non-contact locks comprising a transceiver antenna embedded in the wall at the entrance of a building and connected to a

  computer center hidden safely inside the building

  ment and which has the data allowing the authorization of access of the various speakers who all have a contactless electronic key. Access management is centralized and organized

  daily by different servers which distribute the data

  born in different buildings by various means of communication in complete safety. Each contactless key is identified and

  authorized or not to open the door of the building.

  A first contactless technology is based on the frequency of 125 kHz. But for historical reasons and also by its relative slowness in exchanging complex information, it has been used only in simple systems that do not have a great requirement in terms of security. To increase the complexity of contactless information exchange with greater speed, another technology has been developed, based on the frequency of 13.56 MHz. It is now accepted as the standard in all contactless systems and thereafter,

  we mean by the term "contactless" this technology.

  Today there is an application of this techno-

  housed in electronic locks, which are essential

  ment in new buildings because it requires strenuous installation work; these electronic locks, due to their imposing size, are difficult to integrate into old buildings. Figures 1 and 2 schematically represent this type of electronic locks. They include a housing 1 closed by a front plate 2 by means of tamper-proof screws 3. The front plate 2 is generally made of steel, of sufficient thickness to resist vandalism. This material constituting a magnetic screen, there is provided a window 4, generally flat and rectangular of size approximately 7 × 8 cm and made of polycarbonate, allowing the passage of a magnetic field produced by a

  antenna 5 connected to a transceiver 6. A rail protection

  magnetic 7 isolates the transceiver 6 from the field produced by

the antenna.

  The disadvantages of these locks of the prior art are firstly their size and secondly their vulnerability to

  vandalism by the fragility of polycarbonate windows.

  However, currently, the electric door strike control locks with conventional key, shown in FIG. 3, occupy a very precise and limited volume. They consist of a part 8 external to the wall through which the key is inserted, with a diameter of 2.9 cm mounted against a wall 9 of a building using a nut 10. The nut 10 corresponds to one or more cylindrical and threaded portions 2.5 cm in diameter from the body 11 of the lock. This body ends in a camshaft 12, movable around an axis 13. In addition, an electrical contact is mounted in a part 14, fixed to the body 11 of the lock by a metal arm 15. The fact of turning a key in the lock causes rotation of the cam 12 which thus operates an electrical connection between two contacts of the connector 14, which triggers

opening the door.

  An object of the present invention is to provide a new electronic lock operating with cards without

  contact, compatible with current standardized systems presented

  both the highest degree of security and a size and volume allowing it to be inserted into the mounting holes

  pre-existing conventional locks (Figure 3).

  In addition, vandalism represents a great constraint which is added to the previous technical constraints. Indeed, intruders can try to enter buildings and mistreat the antennas which, by force, are vulnerable to

  by their arrangement outside the building.

  Another object of the invention is therefore to improve the

  resistance to vandalism compared to previous solutions.

  To achieve these objects, the present invention provides a contactless electronic lock comprising an antenna loop backed by a ferrite, characterized in that the ferrite comprises at least one protuberance or boss making

protruding outwards.

  According to an embodiment of the present invention, the antenna is protected by a cover, and the external surface of the cover does not occupy an area greater than a circle of

diameter 45 mm.

  According to an embodiment of the present invention, the antenna is protected by a cover, and the external surface of the cover is curved, its point furthest from the wall is

  located at least 1 cm from it.

  According to an embodiment of the present invention,

  the cover has a rounded and convex shape.

  According to an embodiment of the present invention, the angle between the tangent to the cover and the normal to the plane of the wall at the point of lateral contact of the cover with the wall

is greater than 19 degrees.

  According to an embodiment of the present invention, the lock has two parts, an antenna part comprising at least one antenna loop, ferrite, a cover and a body and a radio part comprising a transceiver, these

  two parts being mechanically connected by a screw and electrically

only by cable.

  According to an embodiment of the present invention, the body has a threaded part to cooperate with a nut

  arranged on the other side of a wall.

  According to an embodiment of the present invention,

  the radio part is arranged in the body.

  According to one embodiment of the present invention, the lock contains a metallic means between the antenna loop (s) and the outer layer of the lock to better resist

to vandalism.

  According to an embodiment of the present invention, the lock includes a light in its center indicating whether access

is allowed or denied.

  According to an embodiment of the present invention,

  the radio is operated intermittently.

  The objects, characteristics and advantages of the

  present invention are detailed in the description

  following of particular embodiments made for non-

  limiting in relation to the appended figures among which: FIG. 1 represents a top view of a conventional contactless lock of the prior art; Figure 2 shows a perspective view of a conventional contactless lock of the prior art; Figure 3 shows a side view of a conventional lock; Figure 4 shows a side view of a possible form of a contactless lock of the present invention; Figure 5 shows a sectional view of a lock according to the invention mounted in a wall; FIG. 6 represents a perspective view of the main elements of the "antenna" part of a lock according to the invention; Figure 7 shows a sectional view of the main elements of the "antenna" part of a lock according to the invention; FIG. 8 represents a plan projection of a protective dome according to the invention;

  FIG. 9 represents a plan projection of a cover

  antenna key according to the invention; Figure 10 shows a sectional view of the antenna cover according to the invention; and Figure 11 shows sectional views of other

  solutions for the ferrite part according to the invention.

  A first solution would be to propose an electronic lock as described in FIG. 4. A plate 21,

  cylindrical or hexagonal, made of plastic, resistant

  flame aunt, for example in thermoset, covers an antenna

  22 with a diameter of about 5 cm supplied by a transmitter-

  receiver 23, such as the transceiver 6 of FIG. 1.

  This antenna 22 rests on a disc-shaped ferrite 24, allowing the field lines to be looped back, which would otherwise be absorbed in the metal wall 25. The assembly is fixed to a threaded body 26 to be tightened by a nut 27 against the wall, in an operational position as shown in Figure 4. The transceiver 23 is arranged in the space

lying just behind the wall.

  The operating principle is similar to

  electronic antennas previously described in Figures 1 and 2.

  Despite the reduction in size, they still have the disadvantage of having a cover diameter of at least 6 cm, larger than that of conventional conventional locks and of reusing a transceiver 23 of too large a size, which does not do not necessarily make them compatible with the slots reserved for conventional systems (Figure 3). In addition, the flat shape of the cover 21 makes it vulnerable to acts of vandalism with sharp tools, and not very ergonomic since it forces the user to almost press his card against the wall since the range of such a lock is less '' order of 2 cm, measured from the antenna 22, which requires a particular gesture and a restrictive way of taking the

card in hand.

  Thus, the invention, in one of its embodiments

  tion, proposes the structure shown in Figure 5. There is a modular lock composed of two parts, one part

  "antenna" 30 and a "radio" part 50.

  The “antenna” part 30 according to the invention, shown in exploded perspective view and in exploded section view in FIGS. 6 and 7, comprises a printed circuit containing one or more loops serving as antenna 31 with a diameter of less than 3 cm, and a ferrite 32. The ferrite 32 has the shape of a disc 33 with a thickness of about 2 mm and a diameter of about 3 cm, comprising at its center two protrusions 34 in the form of a semicircle of the same radius, height 2 mm and about 2 mm thick centered on the center of the disc. These two protrusions 34 surround a circular opening in the center of the ferrite, allowing the integration of a light-emitting diode (LED) 35. In addition, they correspond to two openings 36 in the printed circuit 31 allowing the fitting of the ferrite 32 in the circuit

  printed 31, inside the antenna loop.

  The ferrite / printed circuit assembly is covered with a

  dome 37, shown in FIG. 8, composed of a metallic wire

  as resistant, for example in hardened steel, in the form of an open spiral. The assembly is covered with a cover 38, molded in a single piece and having no junction to avoid the

  acts of vandalism with a screwdriver and in a very resistant material

  aunt against shocks, cuts and fire, such as a thermoset (it must be a material resistant to vandalism but allowing magnetic fields to pass through, which prevents using

  metal). It has in its center a small window or preferen-

  tially a glass ball 39 with a diameter of about 3 mm playing the role of lens, placed opposite the LED 35 and serving as an indicator. The glass ball can advantageously have its frosted outer surface. The advantage of using said ball rather than a window is threefold: the ball makes it possible to better transmit the light from LED 35 from all angles, giving the effect of being itself the source of light, and is cheaper than a window. It is stuck in the opening of the cover 38 so that it only protrudes by 0.5 mm at most so as not to have a grip. Such a warning light has many possible applications in the fields of computers, cars, air,

control rooms, home automation ...

  As shown in Figures 9 and 10, the projection

  plane of the cover 38 is a disc less than 45 mm in diameter.

  It is broken down into four parts. The lateral part 60 is a truncated cone approximately 2 mm high, making an angle with respect to the normal to the plane of the wall of 19. It is then extended by a portion of torus 61, with a radius of 12 mm. The third part 62 is a connection between this first portion of torus and the fourth part 63, which is a portion of a sphere, with a radius of 10 cm. The connection avoids a sharp angle and gives the cover a rounded shape. Finally, the cover is characterized by its generally rounded shape, by its angle with the plane of the wall and by its point furthest from the

  wall, in its center, which is about 1 cm from it.

  The cover 38 is glued to the threaded body 40 of diameter 25 nmmn adapting to the mounting hole of the lock, so as to have perfect coplanarity between the cover 38 and the body 40 at their contact with the wall 41 ( figure). This antenna is fixed in the wall using a nut 42 which mounts on the threaded part of the body 40, inside the wall 41 to strongly tighten the visible part of the antenna.

  against the outer face of the wall.

  The second part of the invention is the "radio" part which consists of radio electronics, more specifically of the transceiver 51, placed in a standard commercial box 52, in a volume of less than 60 × 40 mm. sides and 20 mm thick. The cover of this housing 52 is fixed to the rear of the antenna body by a screw 53. The transceiver is electrically connected to the antenna by an electric cable 54 secured to the antenna 31 which passes through the body 40 through an opening then

  is connected by a connector to the housing 52.

  An advantage of this electronic lock results from

  its total volume compatible with the old locks represented

  tees in Figure 3. Indeed, we first notice that the outer part of the lock, that is to say the cover 38, has a diameter of less than 45 mm, which is close to the size of the

  classic building access locks.

  Another advantage of the invention comes from the external shape of the lock, which finds an optimal compromise between the resistance to vandalism, the range and the ergonomics of the

  electronic lock. The following advantages will be noted.

  1. The angle of 19 degrees of the cover relative to the normal to the plane of the wall as well as the height of 2 mm of this lateral portion serve to prevent attacks with pliers which would consist in catching the cover to pull it strongly or turn it, while ensuring a minimum size of the

  outside diameter of the electronic lock (45 mm).

  2. The perfect coplanarity between the cover 38 and the body 40 at their contact with the wall 41, obtained by their bonding by affixing the two parts on the same plane and by applying a press, gives the optimal resistance of the lock electronic against attacks with a screwdriver or any other fine object, which consists of inserting said object between the

  wall and lock to pry it out.

  3. The plastic thickness is not constant as in the case of flat locks but variable so as to present a

  thicker on average for better resistance

  ter vandalism, such as attacks with sharp objects, which would tend to damage the most fragile part, the antenna 31. In the best configuration chosen according to the invention, the cover 38 has a rounded shape as shown in Figures 5 , 6, 7 and 10 characterized in that

  the central point is at least 1 cm away from the wall 41.

  4. The previous point also allows the lock to be more ergonomic since the surface of the lock, being further from the wall of the building, makes approaching the contactless card easier: the wall more distance becomes less annoying during the placement of the hand towards the antenna. 5. The material used, allowing the magnetic fields to pass, is a flame-resistant plastic, which resists all the better as the cover 38 is rounded and does not have a sharp angle. In addition, its hardness allows it to resist

  acts of vandalism using pliers, a screwdriver or a knife.

  This solution against vandalism may appear a priori obvious if it is detached from the context of the invention and from the interference between the various constraints of the technology used by the invention. In fact, reduce the size

  of the antenna and increasing the thickness of the cover are two elements

  which reduce the range and performance of the antenna in this technology to 13.56 MHz for this application. This physical reality, explained below and known to a person skilled in the art, represents a great problem since the range of the electronic lock of FIG. 4 for example is only 2 cm, despite the optimization of the power and of the size of the antenna. This shows that the orientation chosen in the present invention seems to go the opposite of what seems possible to

the skilled person.

  First, scope is defined by the measure between the

  outer surface of the cover 38 and the operating position

  as far as possible from the contactless card. Being

  given that the program comes from antenna 31, add a thick-

  plastic cover has the same effect as removing the card without

  contact of the antenna and returns, for the skilled person, to

  further reduce the range of its electronic lock.

  In addition, a person skilled in the art knows that the maximum power

  male allowable emission is limited by value relatively

  weak that the contactless card can withstand before its destruction

  tion. There is therefore no possibility of increasing the power of the antenna to increase the range. The second parameter used by a person skilled in the art is the size of the antenna 31. It is known that the magnetic coupling between the antenna 31 and the loop included in the contactless card is optimal when the two have approximately the same cut. The standard size of the contactless card loops is approximately 72X42 mm. Thus, to obtain the optimal performance of this kind of electronic lock, the skilled person's solution is to optimize the size of the antennas, that is to say to get as close as possible

  the size of the loop contained in the contactless card.

  This is why the chosen solution will not appear obvious to a person skilled in the art who will understand that modifying the external shape of the cover 38 in order to obtain improvements in the electronic lock as regards its ease of installation, its resistance to vandalism. and its ergonomics all there

  retaining its magnetic performance represents an invention

far from obvious.

  The previous solution was obtained thanks to the optimization of the shape of the ferrite which concentrates the field lines and makes it possible to greatly improve the performance of the antenna and, simultaneously, of the electronic lock for all the points mentioned above. -above. Other solutions are possible

  when choosing ferrite as shapes 32a to 32f represent

  shown in Figure 11. All shapes with protrusions

  these or bosses, not flat shapes but moving away from the

  wall towards the center of the antenna go more or less advantageous-

  in the sense of the invention. In summary, one of the principles of the invention is not to use a flat ferrite, which is

  the solution which appears obvious to those skilled in the art.

  Additional protection according to the invention has been integrated between the cover and the antenna / ferrite part. It is a spiral 37 made of hardened steel wire or any other very resistant metal, which follows the rounded interior shape of the

  cover 38 and represents an additional resistance in particular

  against hacksaw attacks. Any other assembly

  metal blage of a shape such that it would only give birth

  very few eddy currents because these stop the ray-

  magnetic, such as simple open loops of metal wires or pieces of metal parts distributed on the inner surface of the cover would represent an equivalent solution. Note that the total volume of this lock is similar to that occupied by conventional locks (Figure 3), which is an advantage. We have seen above the aspects of the invention explaining the advantages of the part

  containing the antenna. This is powered by a transmitter-

  receiver 51 which requires a part of electronics to be mounted during

  installation of the electronic lock.

  According to the invention, the positioning of the "radio" 50 relative to the "antenna" 30 has great flexibility since the "radio" 50 has a freedom of rotation relative to the axis of the body 40, which allows to the lock according to the invention greater adaptability during its installation in tight spaces. In the worst case, it is also possible not to screw the two parts but to leave them only electrically connected by cables, which can still offer

  more positioning flexibility.

  An advantage of the invention is to have been able to reduce the size of the electronic card of the "radio" 50 compared to the prior art of FIG. 1, which allows greater adaptability for the installation of a lock according to the invention in reduced locations. This was possible thanks to the value of the power consumed by the transceiver, 3 watts, and also by the fact that it is not sent this power

  only during 25% of the time because the power is controlled by inter-

  mittence and shared between 4 antennas. This avoids heating problems and thus uses relatively simple components without a cooling system. The principle of controlling multiple antennas intermittently is another

  features of the invention.

  Finally, this modular composition also makes it possible to be able to use the two parts independently of one another, the "antenna" 30 according to the invention being compatible with other models of "radio" 50 and conversely "radio" "50 according to the invention which can be adapted to other models

"antennas" 30.

  Another possible configuration of the invention is to sacrifice the modular aspect of the first embodiment and its ease of maintenance in order to obtain a lock in one piece, even easier to install since it is less bulky by having

  the transceiver in the threaded body 40.

Claims (11)

  1. Non-contact electronic lock comprising an antenna loop (31) attached to a ferrite (32), characterized in that the ferrite comprises at least one protuberance or boss projecting towards the outside of the wall on which this lock is climb. 2. Non-contact lock according to claim 1, the antenna of which is protected by a cover (38), characterized in that the external surface of the cover does not occupy a surface.   greater than a 45 mm diameter circle.   3. Non-contact lock according to claim 1, the antenna of which is protected by a cover (38), characterized in that the external surface of the cover is curved, its point the   farther from the wall being at least 1 cm from it.   4. Non-contact lock according to claim 3, characterized in that the cover (38) has a rounded and convex shape. 5. Non-contact lock according to claim 3, characterized in that the angle between the tangent to the cover and the normal to the plane of the wall at the lateral contact point of the   cover with the wall is greater than 19 degrees.   6. Non-contact lock according to claim 1, characterized in that it comprises two parts, an antenna part (30) comprising at least one antenna loop, ferrite (32), a cover (38) and a body. (40) and a radio part (50) comprising a transceiver (51), these two   parts being mechanically connected by a screw (53) and electrically only by a cable (54).   7. Non-contact lock according to claim 6, characterized in that the body (40) has a threaded part for cooperating with a nut (42) disposed on the other side of a wall (41).   8. Non-contact lock according to claim 6, characterized in that the radio part (50) is arranged in the body (40).   9. Non-contact lock according to any one of   Claims 1 to 8, characterized in that it contains a   metallic means (37) between the antenna loop (s) and the   outer layer of the lock to better resist vandalism.   10. Non-contact lock according to any one of   Claims 1 to 9, characterized in that it comprises a   LED in the center indicating whether access is authorized or denied.   11. Non-contact lock according to claim 6, ca-   characterized in that the radio (50) is controlled intermittently tence.