TRIGGER MECHANISM FOR SMOOTH-BORE FIREARMS

Abstract: A safety device to prevent accidental firing acting on the engagement lever (5) of the hammer (8) in a trigger mechanism for smooth-bore firearms, comprises a pin (13) which extends transversely to the operating plane of the engagement lever (5) sand which has a grooved section (13c, 13d) between larger cylindrical sections (13a, 13b). The pin (13) is axially displaceable between a position in which the cylindrical section (13a) lies adjacent the engagement lever (5), so preventing actuation thereof and corresponding operation of the hammer (8), and a position in which the grooved section (13c, 13d) lies facing the engagement lever (5), so allowing actuation of the latter and of the hammer (8).

Description: This invention relates to a trigger mechanism for smoothbore firearms. A trigger mechanism comprising the first part of the claim is disclosed in CH-A-586 885. As is well known, firearms must be prevented, as a result of being knocked or dropped, from accidentally firing a shot and for this purpose the trigger mechanism has safety devices to prevent the hammer from reaching the firing position and striking the percussion pin. According to CH-A-448 808, there is known a trigger mechanism with a safety device which comprises a positive stop fitted removably at the engagement lever to prevent rotation of this lever. Conventional safety devices are usually fitted on the trigger, so that they securely lock the trigger; in this condition the hammer, engaged by the tooth of the engagement lever, is held in the armed position. As a result of particularly strong knocks or play due to wear or weakening of spring elements, however, the counter-tooth of the hammer disengages itself from the engagement tooth, thus enabling the hammer to reach the firing position notwithstanding the trigger being locked. A safety device that acts directly on the hammer is also proposed, so as to avoid the above-mentioned drawbacks. It was found, however, that with such devices the hammer is effectively locked in the armed position, but if for example due to a knock the engagement tooth disengages itself from the counter-tooth the hammer becomes released immediately into the firing position, resulting in obvious drawbacks. The problem that lies at the heart of this invention is to devise a trigger mechanism which has structural and operating characteristics such as to overcome the drawbacks mentioned as regards the known state of the art. This problem is resolved according to the invention by a trigger mechanism as defined in the characterising part of the claim. The characteristics and advantages of a trigger mechanism according to the present invention will emerge from the following description of a preferred embodiment, given by way of example and not limited by the attached drawings. In these drawings: Figure 1 is a side, schematic cross-sectional view of a trigger mechanism of a smooth-bore firearm according to the invention; Figure 2 is an enlarged scale view of a detail of the mechanism shown in Figure 1; Figures 3 and 4 are plan, schematic and partly cutaway views of the above-mentioned detail of the trigger mechanism in different operating conditions; and Figures 5 and 6 are side, schematic cross sectional view of another embodiment of a trigger mechanism according to the present invention. With reference to the above-mentioned Figures, 1 shows a trigger mechanism as a whole according to the invention for a smooth-bore firearm. The example under consideration refers in particular to a 20-calibre semi-automatic rifle. Mechanism 1 comprises a supporting body 2 in which pivots a trigger 3. At one end 3a of the trigger 3 pivots a release lever 4 with a first arm 4a and a second arm 4b, defining with the first arm an angle of approximately 120°, in which is formed a ledge 4c. Trigger mechanism 1 comprises an engagement lever 5 pivoted in body 2 and operated in rotation by release lever 4 opposing first spring devices 6, as will emerge from the rest of the description. Engagement lever 5 has a first end 5a with an engagement tooth 7 in the opposite part to the release lever 4, as well as an opposing second end 5b in which is formed a counterledge 5c. The said first spring devices 6 are fitted between the first arm 4a of the release lever 4 and the first end 5a of lever 5, and act constantly to press the ledge 4c against the counter-ledge 5c. 8 shows a hammer, also pivoted in body 2; it will be observed that the axes of rotation of hammer 8, engagement lever S and release lever 4, as well as trigger 3 are parallel to each other and extend transversely across body 2. Hammer 8 has a counter-tooth 9 and is angularly movable under the action of the second spring devices 10, fitted between body 2 and hammer 8, from an armed position in which the counter-tooth 9 is engaged and held by engagement tooth 7, to a firing position in which hammer 8, disengaged from tooth 7, strikes percussion pin 11 of the firearm. Trigger mechanism 1 also comprises a safety device 12 to prevent accidental firing, which is in particular designed to prevent hammer 8 from accidentally abandoning the above-mentioned armed position. Device 12 comprises a pin 13 extending transversely as described above, fitted in body 2 in close proximity to engagement lever 5 and sliding between a first position, locking position, and a second position, firing-enable position. In particular, pin 13 has two cylindrical sections 13a and 13b and two annular adjacent grooves 13c and 13d, formed circumferentially between the said cylindrical sections 13a and 13b. Furthermore, there is an annular projection 13e between grooves 13c and 13d, while there are shoulders 13f and 13g between cylindrical section 13a and groove 13c and between groove 13d and cylindrical section 13b. It will be noted that, when pin 13 is in the first locking position, the cylindrical section 13a interferes with the trajectory of the second end 5b and constitutes a positive stop to prevent the rotation of engagement lever 5. Furthermore, pin 13 is shaped so that in the said first position the opposite cylindrical section 13b protrudes beyond body 2. In the second firing-enable position, pin 13 is positioned with groove 13c at end 5b, so as not to interfere with engagement lever 5. In this second position cylindrical section 13a protrudes beyond body 2. Safety device 12 has additional stop devices 14, cooperating with the grooves 13c and 13d and with the shoulders 13f and 13g, to hold pin 13 in the first or second position. These stop devices preferably comprise a pawl 15 with respective spring devices 16, fitted in body 2 and capable of clicking removably into one or other groove 13c, 13d. There follows a description of the operation of the trigger mechanism 1 according to the present invention. Hammer 8 is brought to the armed position in a manner which in itself is conventional, for example by pulling back a breech-block on the firearm, not shown. In the armed position, counter-tooth 9 of hammer 8 is engaged with tooth 7 of engagement lever 5 and held in the armed position by the action of the first spring devices 6. In this condition and with pin 13 in the second position, or fire-enable position, with cylindrical section 13a protruding beyond body 2 and groove 13c at end 5b of engagement lever 5, acting on trigger 3, release lever 4, associated with the trigger, causes engagement lever 5 to rotate so as to disengage counter-tooth 9 and release hammer 8 into the firing position. With pin 13 in the first position, or locking position, with cylindrical section 13a interfering with end 5b, engagement lever 5 is prevented from rotating and consequently countertooth 9 of hammer 8 is prevented from disengaging from engagement tooth 7. It is important to stress that with pin 13 in the locking position neither accidental knocks nor the operation of trigger 3 can cause hammer 8 to abandon the armed position. Furthermore, it should be noted that in order to bring pin 13 into the first or second position it is sufficient to press one or other of cylindrical sections 13a and 13b so that sprung pawl 15 overcomes projection 13e and positions itself in the desired groove 13c or 13d. Figures 5 and 6 show another embodiment of a trigger mechanism according to the invention, intended for 12- calibre semi-automatic rifle of the smooth-bore type. Such a mechanism is indicated as a whole with the reference number 31 and comprises, fitted on a supporting body 32, a trigger 33, a sprung release lever 34 cooperating with the trigger, an engagement lever 35 centrally pivoted in body 32 and rotationally operated by the release lever 34 counteracting with spring devices 36. The engagement lever 35 defines a first end 35a, provided with an engagement tooth 37 oriented toward the release lever 34, and a second end 35b opposite to the first one. Close to tooth 37, a ledge 35c is formed on the engagement lever 35 and it is constantly urged by spring devices 36 toward an end of the release lever 34. A hammer 38, pivoted in body 32 and provided with a counter-tooth 39, is angularly movable upon the action of relative spring means from an armed position in which the counter-tooth 39 is engaged and held by the engaging tooth 37, to a firing position in which the hammer 38 strikes a pin 41 of the firearm. Reference number 42 indicates a safety device, intended for preventing accidental firing, acting on end 35b of engagement lever 35 in order to prevent the rotation of this latter and consequently preventing the hammer 38 from abandoning its armed position. The safety device 42 is completely equivalent to the safety device 12 herein described with reference to figg. 1 to 4; therefore the components of device 42 will be indicated in the figures with the same reference number as those used for safety device 12 and will not be re-described. Furthermore the actuation of the safety device 42 as well as the actuation of the trigger mechanism 31 are to be considered analogous to those of safety device 12 and trigger mechanism 1. The trigger mechanism according to the present invention prevents the risk of accidental firing, how ever hard the firearm may be knocked. Furthermore, the safety device of the trigger mechanism may be operated manually, simply and quickly, and, due to its advanced position in respect to the trigger may be equally used by both right and left handed.

Claims: A trigger mechanism for smooth-bore firearms, of the type comprising a trigger (3, 33), a release lever (4, 34) associated with the trigger (3, 33), an engagement lever (5, 35) operated in rotation by the release lever (4, 34) opposing a spring device (6, 36) and having an engagement tooth (7, 37), a hammer (8, 38) which moves angularly under the action of a second spring device (10, 40) from an armed position in which a counter-tooth (9, 39) on hammer (8, 38) is engaged and held by an engagement tooth (7, 37), to a firing position, as well as a safety device (12, 42) to prevent the hammer (8, 38) from accidentally abandoning the armed position, characterised in that the said safety device (12, 42) comprises a positive stop fitted removably at the said engagement lever (5, 35) to prevent rotation of the latter, wherein the said safety device (12, 42) comprises a pin (13) which has at least one cylindrical section (13a), two annular grooves (13c, 13d) formed circumferentially and an annular projection (13e), the said pin (13) extending transversely in relation to the engagement lever (5, 35) and sliding between a first locking position in which the cylindrical section (13a) meets and interferes with the said engagement lever (5, 35) and constitutes the said positive stop and a second fire-enable position in which one of said two grooves (13c) meets with the engagement lever (5, 35), there being a stop device (14) to hold pin (13) in the first or second position, wherein the said stop device (14) comprises a spring pawl (15) capable of clicking removably into one or other of the said two grooves (13c, 13d).

Inventors: MARZOCCO, ALESSANDRO
Applicants: LUIGI FRANCHI S.P.A.
Application year: 1990
Main classification: F41A17
IPC codes: F41A17