Patent Description:
Different kinds of key have been present on the market for some time, of flat or corrugated type that are reversible and not, having a bit that combines teeth, recesses, ridges and movable elements configured and arranged to interact with the encryption elements present in the lock.

Obviously, it is possible to make the key extremely secure with a suitable design of the combination of the elements that make up the bit.

In some cases, the key bit elements are fixed crests protruding from the surface of the key that may constitute an obstacle when the key is inserted into specific types of cylinder lock, in which the base of the cylindrical rotor is covered by a special protective disc. A key with a simpler bit that is for example devoid of fixed elements protruding from the plane of the key could eliminate the aforesaid drawback but could at the same time be exposed to fraudulent duplication.

Keys also exist in which the bit has a movable element that for constructional reasons is restricted to a very limited movement that is not always appropriate to ensuring reliable operation. <CIT>, <CIT>, <CIT> disclose a key for a lock according to the preamble of claim <NUM>.

The technical task of the present invention is to realise a key for a lock which enables the decried technical drawbacks of the prior art described above to be eliminated.

Within the context of this technical task, an object of the invention is to realize a very secure key for a lock.

Another object of the invention is to realise a key for a lock that is practical and convenient to use.

Another object of the invention is to realise a key for a lock that is difficult to duplicate. Another object of the invention is to realise a key for a lock that is reliable and resistant. The technical task, as well as these and other objects, according to the present invention, are achieved by a key for a lock, comprising a grip, a blade, at least one lever having a first movement receiving arm for receiving the movement from a sensor formed by a fixed pin and a second actuating arm for actuating an encryption element of the lock, said lever being pivoted on the blade with an axis of oscillation thereof that is transverse to the longitudinal axis of the blade, said lever being housed in a groove of a main face of the blade, said groove having a depth dimension in the direction of the thickness of said blade that is less than the thickness of said blade and extending longitudinally along said blade as far as the end of said blade opposite said grip, said lever being positioned entirely inside said groove in an inactive position to interact with said sensor, being characterized in that a retaining spring of said lever is further provided in an inactive position, said spring being configured and arranged to return said lever automatically to an inactive position after each oscillation.

In a preferred embodiment of the invention said spring protrudes from a seat obtained in said groove.

In a preferred embodiment of the invention said spring has a base with a form matching said seat.

In a preferred embodiment of the invention, said seat is formed by a print in a bottom of said groove.

In a preferred embodiment of the invention, said spring is interlocked between said seat and said first arm of said lever.

In one embodiment of the invention, said spring is helical.

In one embodiment of the invention, said helical spring is tapered.

In another embodiment of the invention, said spring is plate-shaped and has the base and a tilted arm projecting from the base.

In a preferred embodiment of the invention, said spring is in a first compression state between said seat and said first arm of said lever when said lever is in said inactive position, and in a second state of greater compression between said seat and said first arm of said lever when said lever is in an active position in which said second arm protrudes outside said groove.

The key according to the invention, owing to the provision of the spring, has secure, precise and reproducible lever movements that improve the performance of the key even over the long term.

The spring can be advantageously returned by hand to position simply and easily during the key assembly step without particular operations like welding, gluing, fixing with screws, etc., that, during miniaturisation of the components, can be particularly tricky. In practice, it is sufficient to position the spring between the spring seat and the lever and only subsequently fit the rotation pin of the lever.

In addition to long-term operating reliability, the key thus has benefits from a simplified manufacturing process.

In this connection, creating the seat for the spring requires a milling processing that is moreover already envisaged for the realisation of the groove.

With a single milling processing, the groove can then be obtained in which the seat of the spring is already arranged inside the groove.

In addition, the spring can be made of material, for example harmonic steel, which is perfectly resistant to atmospheric agents without counting that the position thereof proximal to the free end of the blade makes cleaning with a single jet of air possible to remove a possible accumulation of powder.

The key according to the invention does not moreover have fixed elements protruding from the plane of the key and is usable without prejudice in applications using cylinder locks with the cylindrical rotor protected by a protective disk.

Providing an oscillating lever moreover makes fraudulent duplication of the key extremely complicated.

The lever has a rocker movement that increases the stroke of the second lever arm and thus the grip of the encryption element of the lock.

In this manner, the lever acts with extreme efficacy and reliability for actuating the encryption element of the lock.

Further features and advantages of the invention will become more apparent from the description of a preferred, but not exclusive, embodiment of the key for a lock according to the invention, which is illustrated by way of approximate and non-limiting example in the appended drawings, in which:.

Equivalent parts in the following description will be indicated with the same numerical reference.

With reference to the cited figures, a key <NUM> for a lock <NUM> is shown.

In <FIG>, <FIG> and <FIG> we shall refer to a preferred solution that has a flat reversible key and a cylinder lock.

The scope of the invention can however be extended to a key of a different type, for example a corrugated key <NUM> illustrated in <FIG>, or to a non-reversible key.

The key <NUM> comprises a grip <NUM> and a blade <NUM> bearing the bit of the key <NUM> adapted to interact with the encryption elements present in the lock <NUM>.

In the case of the flat key illustrated in <FIG> from <NUM> to <NUM>, <NUM> and <NUM> the bit of the key <NUM> comprises in a known manner on each of the two opposite main faces <NUM> of the blade <NUM> of the key <NUM> one or more rows of recesses <NUM> aligned according to the longitudinal axis of the blade <NUM>. Possibly, as shown, the bit can comprise in a known manner also on each of the two opposite secondary side faces <NUM> of the blade <NUM> one or more rows of recesses <NUM> aligned according to the longitudinal axis of the blade <NUM>.

In the case of the corrugated key <NUM> illustrated in <FIG>, the bit of the key <NUM> comprises in a known manner recesses <NUM> of various shape and depth along the lower secondary face <NUM> of the blade <NUM> of the key <NUM>.

Advantageously, on each main face <NUM> of the blade <NUM> of the flat reversible key illustrated in <FIG>, <FIG> and <FIG>, and on a main face <NUM> of the blade <NUM> of the corrugated key illustrated in <FIG>, a lever <NUM> is fitted having a first movement receiving arm <NUM> and a second arm <NUM> actuating an encryption element of the lock <NUM>.

It remains understood that in any other case in which the key is not reversible, there is just one lever <NUM> fitted selectively to one of the two main faces <NUM> of the blade <NUM> of the key <NUM>.

Alternatively, the lever <NUM>, in a different embodiment of the invention, can be fitted to a secondary face <NUM> of the blade <NUM> of the key <NUM>.

Each lever <NUM> is pivoted by a pin <NUM> on the blade <NUM> of the key <NUM>.

The axis of oscillation of the lever <NUM> is transverse to the longitudinal axis of the blade <NUM> of the key <NUM>.

The first lever arm <NUM> and the second lever arm <NUM> are exposed on the main face <NUM> of the blade <NUM> of the key <NUM>.

The lever <NUM> is housed in a groove <NUM> of the main face <NUM> of the blade <NUM> of the key <NUM>.

The groove <NUM> extends longitudinally along the blade <NUM> of the key <NUM>.

In particular the groove <NUM> extends as far as the end <NUM> of the blade <NUM> of the key <NUM> opposite the grip <NUM> of the key <NUM>.

The groove <NUM> has a width, length and depth that are such as to house entirely therein the lever <NUM> when the latter adopts an inactive position illustrated for example in <FIG>.

The lever <NUM> also has an active position in which the second arm <NUM> thereof protrudes outside the groove <NUM>.

The key <NUM> has suitable releasable retaining means of the lever <NUM> in the inactive position. The retaining means comprises a spring <NUM> configured and arranged to return the lever <NUM> automatically to the inactive position after each oscillation.

The spring <NUM> protrudes from a seat <NUM> obtained in the groove <NUM>.

The spring <NUM> has a base 15A with a form matching the seat <NUM>.

The base 15A of the spring <NUM> is preferably flat.

The seat <NUM> is formed by a print 16A in the bottom 13A of the groove <NUM>.

The spring <NUM> is interposed between the seat <NUM> and the lever <NUM>, in particular between the seat <NUM> and the first arm <NUM> of the lever <NUM>.

The spring <NUM> is more precisely simply interlocked between the seat <NUM> and the first arm <NUM> of the lever <NUM>.

The spring <NUM> can be helical, and in particular tapered, as illustrated in <FIG>, and be more precisely arranged with the axis M thereof orthogonal to the rotation pin <NUM>.

Alternatively, the spring <NUM> can be plate-shaped as illustrated in <FIG> and <FIG>, and have in particular the base 15A and a tilted arm 15B projecting from the base 15A.

The tapered or plate-shaped conformation of the spring <NUM> results in a significant saving in overall dimensions that is particularly useful for a construction in which the groove <NUM> has the minimum possible dimensions in order not to weaken the blade <NUM> of the key <NUM> structurally.

The base 15A of the spring <NUM>, the larger base 15A in the case of the tapered helical spring <NUM> illustrated in <FIG>, is positioned exactly in the seat <NUM>.

The spring <NUM> is in a first compression state between the seat <NUM> and the first arm <NUM> of the lever <NUM> when the lever <NUM> is in the inactive position: in this inactive position of the lever <NUM> the second lever arm <NUM> is intercepted by a limit stop <NUM> of the lever <NUM> formed by an inner step of the groove <NUM>.

The spring <NUM> is in a second state of greater compression between the seat <NUM> and the first arm <NUM> of the lever <NUM> when the lever <NUM>, appropriately stressed by the sensor <NUM>, is in the active position in which the second arm <NUM> protrudes outside the groove <NUM>.

Advantageously, when the force acting on the first arm <NUM> is released, the lever <NUM> can return automatically and precisely to the inactive position by effect of the strain of the spring <NUM> that terminates when the second lever arm <NUM> is intercepted by the limit stop <NUM> of the lever <NUM>.

Advantageously, the second arm <NUM> of the lever <NUM> has a greater length than the first arm <NUM> of the lever <NUM> so as to increase the movement of the encryption element.

In other embodiments of the invention, the length of the two lever arms can be the same or the second lever arm <NUM> can be of a shorter length than the first lever arm <NUM>.

The key <NUM> works in combination with a cylinder lock having a stator <NUM> that houses a cylindrical rotor <NUM> provided with a slot <NUM> for inserting the key <NUM>.

The cylindrical rotor <NUM> of the lock <NUM> houses a series of encryption elements formed by pins <NUM>, <NUM>, <NUM>', <NUM> of different type and a sensor <NUM> adapted to interact with the first lever arm <NUM>.

The encryption pins <NUM>, <NUM>, <NUM>', <NUM> and the sensor <NUM> are aligned along the axis of the cylindrical rotor <NUM> and in particular they are positioned at the same diameter plane as the cylindrical rotor <NUM> on the same side as the insertion slot <NUM> of the key <NUM>.

The encryption pins <NUM>, <NUM>, <NUM>', <NUM> are movable along radial channels of the cylindrical rotor <NUM> that on one end open onto the annular part 22a of the stator <NUM> and on the other end open onto the slot <NUM> for the key <NUM>.

The encryption pin <NUM> is a passive pin consisting of a single piece with frustoconical ends.

When the key <NUM> is inserted into the slot <NUM> (<FIG>, <FIG>), by effect of the interaction of the pin <NUM> with the bit of the key <NUM>, the pin <NUM> is free to translate and release the end thereof from the relative engagement seat <NUM> provided on the inner side of the annular part 22a of the stator <NUM>. This condition thus enables the rotation of the cylindrical rotor <NUM>.

The encryption pin <NUM> comprises a male part 19a and a female part 19b engaged with the male part 19a with interposition of an elastic element 19c. The female part 19b has a frustoconical end adapted to interact with the bit of the key <NUM> and an insertion end of the male part 19a. The male part 19a has an end inside the female part 19b and a frustoconical end outside the female part 19b and engageable in a seat <NUM> of matching shape present on the inner side of the annular part 22a of the stator <NUM>. The male part 19a moreover has a perimeter recess 19a'. When the key <NUM> is not inserted into the slot <NUM> (<FIG>) the frustoconical end of the male part 19a is engaged in the seat <NUM> thereof and the female part 19b by effect of the action of the elastic element 19c is extended from the male part 19a and assumes a position in which the insertion end thereof of the male part 19a is aligned with the recess 19a' of the male part 19a. In this position, if an attempt is made to rotate the cylindrical rotor <NUM>, the male part 19a is free to rotate angularly so as to wedge between the cylindrical rotor <NUM> and the stator <NUM> and prevent rotation of the cylindrical rotor <NUM>. On the other hand, when the key <NUM> is inserted into the slot <NUM> (<FIG>, <FIG>), the frustoconical end of the male part 19a is engaged <NUM> in the seat thereof but the female part 19b by effect of the interaction with the bit of the key <NUM> is retracted towards the male part 19a, assuming a position in which the insertion end of the male part 19a is staggered by the recess 19a' of the male part 19a. In this position, the female part 19b acts as a translation guide for the male part 19a. Thus if an attempt is made to rotate the cylindrical rotor <NUM>, the male part 19a is guided to translate in the female part 19b until the frustoconical end of the male part 19a exits the seat <NUM> thereof and is retracted into the radial channel of the cylindrical rotor <NUM>. In this case, the rotation of the cylindrical rotor <NUM> can take place.

The solution illustrated in <FIG> and <FIG> provides an encryption pin <NUM> consisting of a single piece adapted to interact with a lock nut <NUM> movable in contrast and by action of an elastic element <NUM> in a seat <NUM> obtained on the inner side of the annular part 22a of the stator <NUM>. When the key <NUM> is not inserted into the slot <NUM> (<FIG>) the lock nut <NUM> by effect of the action of the elastic element <NUM> is protracted partially into the radial channel that houses the pin <NUM>. In this position, if an attempt is made to rotate the cylindrical rotor <NUM>, the lock nut <NUM> arranged straddling the cylindrical rotor <NUM> and the stator <NUM> prevents the rotation of the cylindrical rotor <NUM>. On the other hand, when the key <NUM> is inserted into the slot <NUM> (<FIG>), by effect of the interaction of the pin <NUM> with the bit of the key <NUM> the point of contact between the pin <NUM> and the lock pin <NUM> is positioned at the cylindrical interface surface between the annular part 22a of the stator <NUM> and the cylindrical rotor <NUM>. In this case, the rotation of the cylindrical rotor <NUM> can take place.

The solution illustrated in <FIG> has on the other hand an encryption element <NUM>' that is equivalent in operation to the encryption element <NUM> from which it differs structurally in the flat rather than frustoconical shape of one end of the female part.

Encryption of the lock can comprise encryption elements that are also different in arrangement, number and type from those that have just been disclosed.

In the lock illustrated in <FIG> and <FIG> the sensor <NUM> is formed by a fixed pin positioned above the last encryption element on the side of the cylindrical rotor <NUM> opposite the side from which the key <NUM> is inserted.

In this case, the lever <NUM> has the first lever arm <NUM> in a position proximal to the end <NUM> of the blade <NUM> of the key <NUM> and the second lever arm in a position distal from the end <NUM> of the blade <NUM> of the key <NUM>.

Also the sensor <NUM> can however be different in arrangement and type and the key <NUM> has to be anyway conformed in a congruent manner.

With reference on the other hand to the solution illustrated in <FIG>, the lever <NUM> has the first lever arm <NUM> in a position that is distal from the end <NUM> of the blade <NUM> of the key <NUM> and the second lever arm in a position that is proximal <NUM> to the blade <NUM> of the key <NUM>, because the sensor <NUM> is now positioned before the last encryption element <NUM>'.

In the solution illustrated in <FIG>, also the structure of the sensor <NUM> is different. The sensor <NUM> has in this case a pin 21a that is movable in a radial channel <NUM> of the cylindrical rotor <NUM> in contrast and by action of an elastic element 21b interposed between the movable pin 21a and a housing 21c fixed in said radial channel <NUM>.

The lever <NUM> operates in the following manner.

Before the key <NUM> is inserted into the slot <NUM> of the cylindrical rotor <NUM> the spring <NUM> retains the lever <NUM> in an inactive position completely inside the groove <NUM>.

When the key <NUM> is inserted into the slot <NUM> of the cylindrical rotor <NUM>, the first lever arm <NUM> interacts with the sensor <NUM> from which it receives a force that overcomes the elastic force exerted by the spring <NUM> to retain the lever <NUM> in an inactive position and generates on the lever <NUM> a rotation moment owing to which the lever <NUM> moves to the active position.

By effect of the rotation of the lever <NUM> the second lever arm <NUM> actuates an encryption element, in particular, the encryption element <NUM> in the solution illustrated in <FIG> and <FIG> and the encryption element <NUM>' in the solution illustrated in <FIG>.

The encryption element actuated by the lever <NUM> moves from the rotation locking position of the cylindrical rotor <NUM> to the position that enables the rotation of the cylindrical rotor <NUM>.

More in general, by effect of the interaction with the bit of the key <NUM>, also all the other encryption elements move to the position that enables the rotation of the cylindrical rotor <NUM>.

The encryption pin actuated by the lever <NUM> can naturally also be a pin with the structure of the pin <NUM>, or yet another pin.

The key for a lock thus conceived is susceptible to numerous modifications and variations, all falling within the scope of the inventive concept, as defined by the claims.

Claim 1:
A key (<NUM>) for a lock (<NUM>), comprising a grip (<NUM>), a blade (<NUM>), at least one oscillating lever (<NUM>) having a first movement receiving arm (<NUM>) for receiving the movement from a sensor (<NUM>) formed by a fixed pin and a second actuating arm (<NUM>) for actuating an encryption element of the lock (<NUM>), said lever (<NUM>) being pivoted on said blade (<NUM>) with an axis of oscillation thereof that is transverse to the longitudinal axis of said blade (<NUM>), said lever (<NUM>) being housed in a groove (<NUM>) of a main face (<NUM>) of the blade (<NUM>), said groove (<NUM>) having a depth dimension in the direction of the thickness of said blade (<NUM>) that is less than the thickness of said blade (<NUM>) and extending longitudinally along said blade (<NUM>) as far as the end (<NUM>) of said blade (<NUM>) opposite said grip (<NUM>), said lever (<NUM>) being positioned entirely inside said groove (<NUM>) in an inactive position to interact with said sensor (<NUM>), characterised in that a retaining spring (<NUM>) of said lever (<NUM>) being further provided in an inactive position, said spring (<NUM>) being configured and arranged to return said lever (<NUM>) automatically to an inactive position after each oscillation.