GB1596947A

GB1596947A - Magnetic security lock and key therefor

Info

Publication number: GB1596947A
Application number: GB23743/78A
Authority: GB
Original assignee: RHONE ISERE
Current assignee: RHONE ISERE
Priority date: 1977-06-07
Filing date: 1978-05-30
Publication date: 1981-09-03
Also published as: BE867809A; IT7868310A0; FR2393907A1; FR2393907B1; IT1108593B; DE2823481A1; ES470529A1

Description

(54) MAGNETIC SECURITY LOCK AND KEY THEREFOR (71) We, RHONE-ISERE, a French Body Corporate of, 16 à 28, rue des Tuileries, Lyon (Rhone), France, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - The present invention relates to a magnetic security lock of the barrel type, more especially although not exclusively adapted for a cylindrical key.

According to one aspect of the present invention, we provide a magnetic security lock of the barrel type, comprising, in combination, a rotor of non-magnetic material provided with holes in which magnetic locking members are mounted to be moved along a radial direction when displaced by the magnetic repulsion of key magnets of a key inserted in the barrel to operate the lock, and a stator of non-magnetic material which is associated with at least one peripheral element of - ferromagnetic material and has on its internal face recesses which said magnetic locking members may enter when a key is withdrawn to allow the magnetic locking members to be attracted towards said at least one ferromagnetic peripheral element, the recesses and the magnetic locking elements being arranged such that at any one axial station along the lock there are several magnetic locking elements spaced at intervals around the axis of the rotor and several said recesses spaced around the stator at the same interval.

The invention also provides a key for a magnetic security lock, comprising a cylindrical shank, and magnetic poles in the cylindrical surface of said shank, arranged such that said magnetic poles are arranged in sets along generatrices of the cylindrical shank and that at any one axial station there are several said poles spaced at intervals around the axis of the shank.

This allows a very considerable number of possible combinations to be provided, as the "springless" arrangement of the locking ele- ments of the rotor makes them less bulky, and therefore more easily grouped close together, than is possible where return springs are required in the rotor.

The magnetic return of the magnetic locking elements of the rotor, obtained by a peripheral, magnetically attracting element, made for example of mild steel, renders it unnecessary to use return springs or other mobile components.

This neat solution, since it takes advantage of the magnetic properties of magnets, is all the more advantageous using a single peripheral element permitting the attraction of all the magnetic locking elements of the rotor, what ever their number and disposition, if this peripheral element is made in the form of a sleeve which surrounds the stator of non-magnetic material. Of course, the arrangement of the magnetic locking elements of the rotor, and of the peripheral element or elements of the stator, should be correctly determined such that the attraction of the magnets of the rotor for the magnets of the key, when the key is inserted, is greater than the attraction by the sleeve or other peripheral element.

In one particular embodiment, the magnetic locking elements of the rotor are cylindrical magnets disposed along the generatrices of the rotor, the recesses on the internal face of the stator being constituted by longitudinal grooves of a width slightly greater than the diameter of each said magnetic locking element. It will readily be understood that when the magnetic locking elements of the rotor are attracted towards the external sleeve, they will penetrate in the longitudinal grooves of such a grooved stator to prevent rotation of the rotor.

This arrangement of the magnetic locking elements along generatrices also makes it possible to provide the peripheral attraction elements for these elements in the form of several longitudinal tongues or leaves placed in the grooves of the stator, along the generatrices of the stator and opposite the said longitudinal grooves on the internal face of the stator.

The separation of the magnetic locking elements of the rotor must correspond to the separation of the magnets of the cylindrical key over all its surface, and thus permits the positioning of a higher number of magnets in the key and in the stator, and consequently of enabling a large number of possible combinations to be achieved, since each magnet offers two possibilities according to its orientation.

In any case, the invention will be better understood with the aid of the following description, with reference to the attached schematic drawing representing by way of nonlimiting example two particular embodiments of this magnetic security lock. In the drawings: Figure 1 is a longitudinal sectional view of a lock according to the invention, with the key inserted in the rotor, the plane of section passing through the axis of the lock; Figure 2 is a sectional view similar to Figure 1, showing the same lock but with the key withdrawn; Figure 3 is a transverse sectional view through the lock and the key, taken along line 3-3 of Figure 1; Figure 4 is another transverse sectional view through the lock alone, taken along line 11 of Figure 2; Figure 5 represents the key alone, viewed in top plan and on small scale;; Figure 6 is a transverse sectional view similar to Figure 3, but illustrating a variant of the lock according to the invention; and Figure 7 shows the stator alone of the lock of Figure 6, seen in perspective.

In the Example here particularly described, and shown in Figures 1 to 5 of the drawing, there will be considered a lock of the barrel type the opening and closing of which are obtained by the introduction of a cylindrical key 1 in the axial bore 2 of a rotor 3 which is able to turn within a stator 4.

The rotor 3, formed of non-magnetic material, for example of brass, has blind cylindrical holes 5 which open at its outer surface but do not reach the bore 2, the floor of these holes 5 being separated from the bore 2 by a floor of non-magnetic material 6 as small as possible in thickness. In each hole 5 is placed a magnetic locking element in the form of a cylindrical permanent magnet 7 able to displace in the hole along its axis, that is to say along a direction which is radial with respect to the rotor 3.In the particular embodiment here considered, the disposition of the holes 5 and consequently of the magnets 7 of the rotor 3 is as follows : - There are provided six groups of holes 5, each group comprising a set of three holes 5 which hold three magnets 7 with the axes of the holes and magnets of that set situated in the same transverse plane such as that of Figure 3 or of Figure 4 and angularly spaced to form angles of 1200. Further, an angular separation of 60 exists between two consecutive groups of holes 5 and of magnets 7 axially arranged along the rotor 3, such that the arrangement of Figure 3 is 60 rotated with respect to the arrangement of Figure 4.

The stator 4, surrounding the rotor 3, is also of non-magnetic material such as brass.

On its internal face it has six longitudinal grooves 8 each having a peripheral content or width which is slightly greater than the diameter of the magnets 7, the interval between two consecutive grooves 8 corresponding to an angle of 60 so that out of the six magnets 7 of two consecutive groups along the rotor, only one magnet will engage each groove 8. The stator 4 is itself surrounded by a sleeve 9 of ferromagnetic material, in this case mild steel.

The key 1, provided of non-magnetic material, has holes in which are fixed other permanent magnets 10 each of which has its visible face flush with the exterior of the cylindrical key.

The arrangement of the magnets 10 of key 1 corresponds to that of the magnets 7 of the rotor 3. Thus, as shown in Figures 1, 3 and 5, there are provided six axially spaced groups of three magnets 10, each group having its three magnets 10 disposed in a single transverse plane and separated by angular intervals of 1200, with a stagger of 60 between two consecutive groups along the key.

The key 1 and the lock present other constructional characteristics necessary to the functioning but which do not form part of this invention but are indicated herebelow to give a complete description of the assembly: At its end opposite the handle 11, the key 1 has a slot 12 which co-operates with a peg 13 projecting radially inwardly from the internal wall of the stator into the interior of the bore 2 and intended for entraining the rotor 3 for rotation (provided the arrangement of the key magnets 10 is the same as that of the rotor magnets 7).

Further, a ball 14 provided in a recess formed in the rotor 3 and engaging in a groove 15 of the key 1, will only allow entry or exit of the key 1 when the rotor 3 is in one particular angular position, for which the ball 14 may be pushed back into a hole 16 formed in the stator 4.

Finally, at the end of the rotor 3 opposite the opening of the bore 2, there is fixed a locking member 17 held in place by a screw 18.

When the key 1 is withdrawn from the bore 2 of the rotor 3, the magnets 7 are attracted radially outwardly towards the mild steel sleeve 9. If the relative positions of the rotor 3 and of the stator 4 are such that the generatrices on which the holes 5 of the rotor occur are situated opposite grooves 8, the magnets 7 penetrate into the grooves 8 by virtue of their attraction in the direction of the sleeve 9. As shown on Figures 2 and 4, the rotor 3 therefore stays locked against rotation by the "keying" provided by the magnets 7, the thrust being thus obtained by a magnetic attraction without the need for return springs for the magnets 7.

When the key 1 is inserted into the bore 2 of the rotor 3, and orientated with respect to the catch 13 as shown in Figures 1 and 3, the magnets 10 of said key 1 attract the magnets 7 of the rotor, provided of course that the chosen polarities of the key magnets 10 match the polarities of the radially outer ends of the rotor magnets 7 so that the "combination" of the lock and key are compatible and the movable rotor magnets 7 are attracted rather than repelled. At each outwardly facing North pole of the key magnet 10 there should correspond a South pole at the end of the corresponding magnet 7 of the rotor 3 facing the bore 2, and vtce versa. Thus, all the movable magnets 7 are attracted radially inwardly by the key 1 and leave the grooves 8 to strike the floors of the holes 5 and to permit rotation of the rotor 3.

If it is otherwise for one or several pairs of coresponding magnets 7 and 10, at least one magnet 7 of the rotor 3 will be repelled into a groove 8 of the stator 4 instead of being attracted by the key 1, and will thus prevent rotation of the rotor 3 with respect to the stator 4.

When the key 1 is again withdrawn, the magnets 7 are attracted to the mild steel sleeve 9 and return into the grooves 8 to lock the rotor 3 with respect to the stator 4.

The number of combinations may be increased by increasing the number of magnets 10 disposed along the generatrices of the key 1 if this key is cylindrical as in the Example described above, or even of polygonal section, each such magnet itself giving two possibilities according to its orientation, in other words according to whether its North pole or South pole faces radially outwardly. Thus, for a given arrangement for the locations of the magnets, there have been provided 2n possible combinations relying purely on their polarities, for example there are 262,144 combinations in the case of the arrangement of 18 magnet locations shown in the drawing. However, it will be preferable to avoid particular combinations with all identical polarities, since this may give rise to excessively simple "picking" of the lock.The number of combinations for a given number of magnets may also be increased by a change in orientation of the magnet; for example, by substituting one of the groups of three magnets which would be expected to be orientated according to Figure 4 by a group of magnets orientated according to Figure 3, the number of combinations is doubled. Furthermore, the orientation of the peg 13 entraining the rotor 3 by co-operation with the slot 12 of the key 1 may be different for a single disposition of the elements, this offering a further possibility for "mechanical" multiplication as opposed to "magnetic" multiplication of the number of combinations.

Figures 6 and 7 illustrate a variant of the lock described above, in which the mild steel sleeve 9 is replaced by distinct longitudinal tongues 19 separated from one another. Each of these tongues 19 is placed in a groove 20 provided in the periphery of the stator 4 along a generatrix thereof, opposite one of the six internal longitudinal grooves 8. The structure of the rotor 3 is not modified, and the operation stays also unchanged in that the magnets 7 are attracted to the tongues 19 and later the grooves 8 to lock the rotor 3 with respect to the stator 4 when the key 1 is withdrawn.

As will be seen, and as will result already from the above description, the invention is not limited to the few embodiments of this magnetic security lock which have been described above by way of example; it embraces, on the contrary, all variants of the embodiments and of the application using the same principle falling within the scope of the claims.It should thus be noted that although the invention is particularly applicable to a cylindrical key in the example described (since this form of key offers a con siderable number of possible combinations because of its greater external surface, and the preferred arrangement of the sets of magnets 7 and 10 quincunxially in accordance with Figure 5) this form of key and rotor is not at all limiting and that the invention stays, by its principle, compatible with keys of other forms such as flat keys, or the polygonal keys men tioned above.

WHAT WE CLAIM IS: 1. A magnetic security lock of the barrel type, comprising, in combination, a rotor of non-magnetic material provided with holes in which magnetic locking members are mounted to be moved along a radial direction when displaced by the magnetic repulsion of key magnets of a key inserted in the barrel to operate the lock, and a stator of non-magnetic material which is associated with at least one peripheral element of ferromagnetic material and has on its internal face recesses which said magnetic locking members may enter when a key is withdrawn to allow the magnetic locking members to be attracted towards said at least one ferromagnetic peripheral element, the recesses and the magnetic locking elements being arranged such that any one said axial station along the lock there are several magnetic locking elements spaced at intervals around the axis of the rotor and several said recesses spaced around the stator at the same interval.

2. A magnetic security lock according to claim 1, wherein the magnetic locking members of the rotor are cylindrical magnets which are disposed along generatrices of the rotor, said recesses on the internal face of the stator being constituted by longitudinal grooves having a width slightly greater than the diameter of the magnets.

3. A magnetic security lock according to claim 2, wherein the magnets of the rotor are separated into several groups of magnets of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

catch 13 as shown in Figures 1 and 3, the magnets 10 of said key 1 attract the magnets 7 of the rotor, provided of course that the chosen polarities of the key magnets 10 match the polarities of the radially outer ends of the rotor magnets 7 so that the "combination" of the lock and key are compatible and the movable rotor magnets 7 are attracted rather than repelled. At each outwardly facing North pole of the key magnet 10 there should correspond a South pole at the end of the corresponding magnet 7 of the rotor 3 facing the bore 2, and vtce versa. Thus, all the movable magnets 7 are attracted radially inwardly by the key 1 and leave the grooves 8 to strike the floors of the holes 5 and to permit rotation of the rotor 3.

If it is otherwise for one or several pairs of coresponding magnets 7 and 10, at least one magnet 7 of the rotor 3 will be repelled into a groove 8 of the stator 4 instead of being attracted by the key 1, and will thus prevent rotation of the rotor 3 with respect to the stator 4.

When the key 1 is again withdrawn, the magnets 7 are attracted to the mild steel sleeve 9 and return into the grooves 8 to lock the rotor 3 with respect to the stator 4.

The number of combinations may be increased by increasing the number of magnets 10 disposed along the generatrices of the key 1 if this key is cylindrical as in the Example described above, or even of polygonal section, each such magnet itself giving two possibilities according to its orientation, in other words according to whether its North pole or South pole faces radially outwardly. Thus, for a given arrangement for the locations of the magnets, there have been provided 2n possible combinations relying purely on their polarities, for example there are 262,144 combinations in the case of the arrangement of 18 magnet locations shown in the drawing. However, it will be preferable to avoid particular combinations with all identical polarities, since this may give rise to excessively simple "picking" of the lock.The number of combinations for a given number of magnets may also be increased by a change in orientation of the magnet; for example, by substituting one of the groups of three magnets which would be expected to be orientated according to Figure 4 by a group of magnets orientated according to Figure 3, the number of combinations is doubled. Furthermore, the orientation of the peg 13 entraining the rotor 3 by co-operation with the slot 12 of the key 1 may be different for a single disposition of the elements, this offering a further possibility for "mechanical" multiplication as opposed to "magnetic" multiplication of the number of combinations.

Figures 6 and 7 illustrate a variant of the lock described above, in which the mild steel sleeve 9 is replaced by distinct longitudinal tongues 19 separated from one another. Each of these tongues 19 is placed in a groove 20 provided in the periphery of the stator 4 along a generatrix thereof, opposite one of the six internal longitudinal grooves 8. The structure of the rotor 3 is not modified, and the operation stays also unchanged in that the magnets 7 are attracted to the tongues 19 and later the grooves 8 to lock the rotor 3 with respect to the stator 4 when the key 1 is withdrawn.

As will be seen, and as will result already from the above description, the invention is not limited to the few embodiments of this magnetic security lock which have been described above by way of example; it embraces, on the contrary, all variants of the embodiments and of the application using the same principle falling within the scope of the claims.It should thus be noted that although the invention is particularly applicable to a cylindrical key in the example described (since this form of key offers a con siderable number of possible combinations because of its greater external surface, and the preferred arrangement of the sets of magnets

7 and 10 quincunxially in accordance with Figure 5) this form of key and rotor is not at all limiting and that the invention stays, by its principle, compatible with keys of other forms such as flat keys, or the polygonal keys men tioned above.

WHAT WE CLAIM IS: 1. A magnetic security lock of the barrel type, comprising, in combination, a rotor of non-magnetic material provided with holes in which magnetic locking members are mounted to be moved along a radial direction when displaced by the magnetic repulsion of key magnets of a key inserted in the barrel to operate the lock, and a stator of non-magnetic material which is associated with at least one peripheral element of ferromagnetic material and has on its internal face recesses which said magnetic locking members may enter when a key is withdrawn to allow the magnetic locking members to be attracted towards said at least one ferromagnetic peripheral element, the recesses and the magnetic locking elements being arranged such that any one said axial station along the lock there are several magnetic locking elements spaced at intervals around the axis of the rotor and several said recesses spaced around the stator at the same interval.
2. A magnetic security lock according to claim 1, wherein the magnetic locking members of the rotor are cylindrical magnets which are disposed along generatrices of the rotor, said recesses on the internal face of the stator being constituted by longitudinal grooves having a width slightly greater than the diameter of the magnets.
3. A magnetic security lock according to claim 2, wherein the magnets of the rotor are separated into several groups of magnets of

which the magnets in any one group are placed in holes whose axes are situated in the same transverse plane respective to said group.
4. A magnetic security lock according to claim 3, wherein each group of magnets comprises three magnets placed in holes whose axes are angularly spaced by intervals and each group is staggered by an angular separation of 60 from the consecutive group, and wherein there are six said longitudinal grooves of the stator angularly spaced at intervals of 60".
5. A magnetic security lock according to any one of claims 1 to 4, wherein there is only one said ferromagnetic peripheral element associated with the stator and it is in the form of a sleeve which surrounds the stator.
6. A magnetic security lock according to any one of claims 2 to 4, wherein there are several said ferromagnetic peripheral elements associated with the stator and they are in the form of longitudinal tongues placed in the grooves formed in the periphery of the stator and extending along generatrices thereof and opposite the said longitudinal grooves on the internal face of the stator.
7. A magnetic security lock constructed and adapted to operate substantially as hereinbefcre described with reference to, and as illustrated in, the accompanying drawings.
8. A key for a magnetic security lock, comprising a cylindrical shank, and magnetic poles in the cylindrical surface of said shank, arranged such that said magnetic poles are arranged in sets along generatrices of the cylindrical shank and that at any one axial station there are several said poles spaced at intervals around the axis of the shank.
9. A key for a magnetic security lock, sub stantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
10. The combination of a key according to claim 8 or 9 with a lock according to any one of claims 1 to 7, wherein the angular spacing intervals of the key magnets correspond to those of the magnetic locking elements and recesses of the lock.