Background art With regard to the manner of ejecting the case of an exploded cartridge, two main groups of firearms may be defined : those with a stable closing system and those with an unstable closing system.

The former, such as double-barrel guns for example, are typically characterized in that the surface which has the function of a breechblock keeps the cartridge immobile during the firing action and therefore all the power released during firing of a shot is transmitted to the projectile which is fired; in this type of firearm, ejection of the used case is performed manually. The latter group comprises automatic weapons, in which part of the energy released during firing of a shot is used to displace the breechblock so as to eject the case without the need for manual intervention.

Both types of firearms have various drawbacks associated with their structure. In particular, double-barrel guns must be opened for the loading and

unloading operations, with a consequent loss of time; also, the unexploded cartridges must be removed manually, thus constituting a source of danger ; the barrels cannot be replaced and therefore only bullets of a predefined size may be fired.

Automatic firearms, on the other hand, become unusable if the first shot is not fired successfully, while pump rifles do not allow aiming in the classic firing position with the butt against the shoulder.

Disclosure of the invention The object of the present invention is therefore to overcome these drawbacks. The object is achieved by means of a device which. allows ejection of the exploded cases to be controlled by means of operation of the trigger itself which controls firing.

The main advantage as regards firearms with a stable closing system consists in the fact that no manual intervention is required by the person using the firearm: therefore, it is not required to open the firearm for loading and unloading; the unexploded cartridges are ejected automatically ; and finally the barrels may be replaced and the size of the cartridges to be fired may be modified.

As regards automatic weapons, a second shot is always available in the event of failure of the first

shot and the power is used entirely for firing owing to the stability of the closing system; moreover, the aiming and firing action is performed in the classic position with the butt against the shoulder.

Brief description of the drawings Further advantages and characteristic features of the invention will emerge more clearly from the detailed description which follows, with reference to the accompanying drawings which show a non-limiting example of embodiment thereof, in which: -Figures 1 and 2 show a side view of the invention before and after assembly of the main functional parts; -Figure 3 shows schematically two opposite side views of the invention, relating to the initial operating condition thereof, with some parts removed so that others may be seen more clearly; -Figure 4 shows a succession of side views similar to those according to Figures 1 and 2 and corresponding to a complete operating phase of the invention; -Figure 5 shows a front view of the invention at the start and at the end of its operating phase; -Figure 6 shows schematically a side view of two alternative solutions of the invention.

Detailed description of the preferred embodiment (s) The invention relates to a rifle breech box which, in the solution shown by way of example in the figures, comprises two channels (6) for two vertical movable barrels (7), but which in any case comprises at least one channel (6) corresponding to at least one barrel (7), a pre-firing chamber (3) into which a cartridge is inserted before firing and from which the associated case is ejected after the shot, a breechblock (1) and associated closing means (5), firing pin (2), a trigger (10), means (8) for constraining the firing pin (2) and the trigger (10) able to ensure that, when the trigger (10) is pressed, the firing pin (2) is released so as to produce the shot, and movement transmission means (9), which are located between the trigger (10) and the means (5) for closing the breechblock (1) and are able to ensure that, again when the trigger (10) is pressed, the closing means (5) no longer engage the breechblock (1), leaving it free to return into the rest position with consequent ejection of the case.

By suitably forming these movement transmission means (9), disengagement of the breechblock (1) from its closing means (5) may be obtained both by prolonging the pressure exerted on the trigger (10) at

the moment of firing and by means of a second pressing action separate from that which produced firing.

The means (8) for constraining the firing pin (2) and the trigger (10) comprise, according to the known art, a connecting lever (8a) and a tooth (8b): in the rest position, the tooth (8b) keeps the firing pin (2) locked, but when the trigger (10) is pressed, the connecting lever (8a) causes rotation of the tooth (8b) which in this way disengages the firing pin (2), causing firing.

The means (5) for closing the breechblock (1) comprise a shutter (4) and a rotating pin (16) which are joined together so that, upon rotation of the pin (16) about itself, the shutter (4) disengages the breechblock (1).

The movement transmission means (9), which may be realised in various forms equivalent to each other, comprise in all cases a tappet (17) which is joined to the pin (16) and able to cause, with its lowering movement, rotation of the pin (16) itself and therefore of the shutter (4)..

In order to obtain lowering of the tappet (17), two possible alternative solutions have been shown, for example, from among the numerous solutions which may be used, but which all fall within the scope of

protection requested with the present patent application.

Referring to the case where a second pressure is exerted on the trigger (10) so that the closing means (5) disengage the breechblock (1), in Figures 3 and 4 it can be seen that the movement transmission means (9) comprise a movable catch (13) which is constrained to the trigger (10) by means of a cam (12) so as to be raised and lowered with respect to its rest position when the trigger (10) is moved forwards and backwards, respectively. In this way the result is achieved that, when the trigger (10) moved beyond its rest position after firing, the catch (13) interferes with the tappet (17), then drawing it downwards when the trigger (10) is pressed a second time.

In particular, distinguishing the two side views of the invention as"pre-firing chamber side"and "closing side", operation of the entire device may described as follows. Figure 3b shows the"pre-firing chamber side"at the start of the firing procedure: after insertion of a cartridge into the pre-firing chamber (3) and manually pushing the breechblock (1) forwards, the firearm is ready for shooting. At the same time, in Figure 3a, which shows the"closing side", it can be seen that the closing system has

already been locked, again manually, by raising the shutter (4) and that the catch (13) is located in the rest position.

By pulling the trigger (10) (Figure 4a), the tooth frees the firing pin (2), causing firing, and the catch (13) moves down into its lowest position; if, at this point, the trigger (10) is released (Figure 4b), the latter moves forward beyond its rest position since the channel (6) is not occupied by the breechblock (1) and allows the return movement upwards of the tooth (8b), and the catch (13) moves upwards until it is located above the tappet (17).

When the trigger (10) is pressed again (Figure 4c), the catch (13) draws with it the tappet (17), causing rotation of the pin (16) and shutter (4) as well as release of the breechblock (1), which occupies the channel (6), and ejection of the case. Releasing the trigger (10) restores the initial situation since, with the channel (6) occupied by the breechblock (1), the pivoting movements of the tooth (8b) stop and the trigger (10) stops in its rest position, as does the catch (13).

If, on the other hand, the breechblock should be released following a prolonged pressure on the trigger (10) at the same time as firing, it will be sufficient

to increase the length of the catch (13) so that, already in the rest position, it is located above the tappet (17), but so that lowering thereof following pressing of the trigger (10) which produces firing is insufficient to draw the tappet (17) downwards. This occurs only by prolonging the pressure exerted on the trigger (10) after firing: the displacement of the shutter (4) and retraction of the breechblock (1) allow ejection of the case, while the trigger (10) returns into its rest position together with the catch (13). It is obvious that this configuration of the movement transmission means (9), shown in broken lines in Figures 3 and 4a, requires a sensitivity which is not within the grasp of everyone and that it will therefore be intended only for those who have already gained a considerable experience in the use of firearms.

By way of an alternative to the solution described above, as shown in Figure 6, the movement transmission means (9) may comprise one or more rotating elements (14; 24) provided with lugs (14a; 24a) which are constrained to the trigger (10) so as to interfere, via one of its lugs (14a; 24a), with the tappet (17) and lower it when the trigger (10) is pressed. The dimensions of the rotating element

(14 ; 24) and the form of the lugs (14a; 24a) determine whether ejection of the case occurs by pressing the trigger a second time after firing or by prolonging the first pressing action, corresponding to detonation.

The firearm which is obtained using a breech box (11) realised in accordance with that described above, may also be semi-automatic, in. the sense that, owing to the autonomous operation of the barrels (7), two barrels (7) may also be provided on the same firearm, one operating repetitively and the other in the manner described above.

The invention thus conceived is subject to numerous modifications and variants, all falling within the scope of the inventive idea. Moreover, all the details may be replaced be technically equivalent elements.

In practice, obviously modifications and/or improvements falling within the scope of the following claims are possible.