The invention relates to a silencer device for firearms, which has an axis along which a central opening is extending for the projectile of the firearm and comprises a support means for attachment to the front of the barrel of the firearm and an outer tube fixed to the exterior of the support means and has an axis falling in said axis of the barrel, and a silencer assembly arranged coaxially around the axis an placed in the interior of the outer tube.

Silencers have long been used for firearms and numerous types of them can be commercially obtained. The extent of the silencing effect depends primarily on the volume of the device (i.e. from its diameter and length), and the higher this volume is, the greater is the sound attenuation will be. The diameter and the length of the devices attachable to firearms are limited, however, by practical considerations, the device should not have an adverse influence on targeting and it should have a limited weight that does not make use inconvenient.

There are silencer devices known with adjustable length or in which a part of the device is displaced from its staring position under the effect of the pressure of gasses.

Such a last mentioned device is described in the publication GB 2 1622929 A, in which an axially sliding silencer part is attached to the barrel of the firearm. This constructional part comprises axially arranged and separated partitions that have cylindrical outer surface provided with openings. The part is encircled by a large casing attached firmly on the barrel of the firearm and with respect to this casing the part can be displaced against the biasing force of a spring. After shooting, the pressing forces of the released gasses push this part in forward direction and a part of the gasses can escape through the openings on the wall of these partitions in a chamber formed in the interior of the casing decreasing thereby the speed and pressure of the gasses.

The drawback of this design lies in that the gasses can arrive in the interior of the large casing only through the small openings of the silencer part against a high flow resistance and the flow of the gasses in the silencer part take place with the initial high pressure and speed. As a consequence, the proposed design does not influence the entering speed and pressure of the gasses.

l In US 4,384,507 a silencer device is described that has variable length, wherein the device consists of two tubes that can be inserted in each other and depending on the silencing task the user can adjust different overall lengths.

In the publication DE 33241986 the silencer device consists of two tubes with adjustable length, wherein not only their overall length but also their angular positions can be adjusted. The adjustment of the angular position is required for the attenuation of the visible throat light.

The task of the invention is to provide a silencer device which, at a predetermined volume, can provide a higher degree of attenuation of the firing sound compared to prior art devices.

The invention is based on the discovery that the decrease of the gasses released at firing should take place prior to their entry in the silencing assembly. In that case the predetermined silencing effect of the silencing assembly will prevail with much lower starting conditions.

According to the invention a silencer device has been provided for firearms, which has an axis along which a central opening is extending for the projectile of the firearm and comprises a stationary casing attached to the barrel (6) of the firearm and a silencer assembly guided for axial linear displacement in the casing wherein according to the invention the silencer assembly can move forward in a limited path section under the effect of the gasses released at firing, and during this forward movement an inner chamber (18) is formed between the end of the barrel (6) of the firearm and the forwardly moving assembly that fills a substantial part of the interior of the casing, in which the gasses expand and their pressure and speed of flow decreases before they enter the silencer assembly.

In a preferred embodiment the casing comprises a support element that can be attached on the front part of the barrel of the firearm and an outer tube fixed to the exterior of the support element, and its axis falls in the axis of the barrel, and the silencer assembly is constituted by an inner tube having silencing partitions, the inner tube (14) is guided in the interior of the outer tube; the device comprises elements that guide the inner tube for axial displacement and limit the extent of the displacement and which are positioned in the space formed between the outer tube and the inner tube at respective rear and front offset positions, and fixed to one of the tubes and slide relative to the other tube; and at least one spring placed between and supported by the limiting elements in the space between the outer and the inner tubes biasing the inner tube to take the rearmost position; wherein the forwardly expanding inner chamber is formed between the front end of the support element and the rear end of the inner tube.

The support element has preferably a threaded bore fitting to the threaded frontal portion of the barrel of the firearm and has a cylindrical our surface connected to the rear end section of the outer tube, and the support element has an outwardly expanding conical part that defines a volume substantially equal with the smallest volume of the chamber.

In a preferred embodiment the rear guiding and limiting element is a shoulder provided at a rear section of the inner tube, the outer diameter of the shoulder is fitting to and guided by the inner diameter of the outer tube.

It is preferred, furthermore if the front guiding and limiting element is a ring provided at the front end of the outer tube that has an inner diameter fitting to and guided by the outer diameter of the inner tube.

It is preferred if the spring is arranged in the space between the rear and from limiting elements.

In another embodiment the front and rear limiting and guiding elements have at least two bores with axes falling in the same line, and thin guiding rods are inserted in these bores, and respective coil springs are positioned around the rods in the space between the outer and inner tubes (12, 14).

In a still further embodiment that the casing is a cylindrical outer tube with an interior comprising a plurality of axially guided telescopic rings spring-biased towards the barrel, and the chamber is provided by the combined volume of chambers formed behind the telescopically forward moving tubes and the end of the barrel.

The invention will now be described in connection with exemplary embodiments thereof wherein reference will be made to the accompanying drawings. In the drawing:

Fig. 1 shows the sectional elevation view of the silencer device according to the invention attached to a handgun;

Fig. 2 shows the sectional view of the silencer device immediately after firing; Fig. 3 shows the sectional elevation view of another embodiment of the silencer device;

Fig. 4 shows the exploded perspective view of the device of Fig. 3 in a smaller scale; Fig. 5 shows the sectional view of the device of Fig. 1 at a slightly later phase of the shooting;

Fig. 6 is a section similar to that shown in Fig. 5 where the silencer device is partially displaced in forward direction;

Fig. 7 is a view similar to Fig. 5 showing the silencer device in a fully forward position; and

Fig. 8 shows the sectional view of an embodiment of the silencer device that has two chambers.

Reference is made now to Fig. 1 in which a schematic view of a handgun 1 is shown that has a spring biased cartridge 3 comprising projectiles 2. The drawing shows trigger 4 of the gun and a schematically shown bolt 5 with a barrel 6 so that at the beginning thereof another projectile 2 is arranged. The barrel 6 comprises a front end provided with a standard thread. A silencer device 10 according to the invention is screwed on the threaded end of the barrel 6 of the handgun 1.

At the rear end of the silencer device 10 a support element 11 is provided which has a cylindrical body and has a threaded bore fitting to the thread of the barrel 6 and has a cylindrical outer surface also provided with a thread. On the outer threaded part of the support element 11 an outer tube 12 is attached that has an axis falling in the extension of the axis of the barrel 6, and at the front end thereof an inwardly projecting ring 13 is arranged that can be formed by the material of the outer tube or it can also be a separate member. The ring will have -as will be described later - an abutting and limiting task. In the interior of the outer tube 12 concentrically therewith an inner tube 14 is arranged that has a smaller diameter, that comprises a shoulder 15 at the rear end region that has an outer diameter fitting to the inner diameter of the outer tube 12, whereby the inner tube 14 can take a guided movement in axial direction along the common longitudinal axis with the outer tube 12. The inner diameter of the ring 13 is fitting to the outer diameter of the inner tube 14 that increases the accuracy of the guiding. In the shoulder 15 at least two but preferable more axial bores are provided, and in the extension of the axes of these bores respective bores, preferably dead-ended bores are provided. In the respective matching pairs of bores respective spring holding rods 16 are arranged, wherein the front end portions of the rods 16 are fixed in the associated bores of the ring 13, and the rods 16 do not prevent axial sliding of the inner tube 14. Respective coil springs 17 are positioned around the rods 16 so that the rear ends of the springs 17 abutting the front face of the shoulder 15 and their front ends abut the rear face of the ring 13. As a consequence of this design the coil spring 17 try to keep the inner tube 14 in the basic position shown in Fig. 1., however, against their biasing force the inner tube 14 can be slid in forward direction. In the drawing it was not shown that in the interior of the outer tube 12 an inner shoulder is provided that limits the forward sliding movement of the inner ring 14.

The front surface of the support element 11 has an outwardly expanding conical shape, and the outer portion of this cone abuts the inner tube 14. In this way when the inner tube 14 is in its initial position a conical chamber 18 is formed behind the tube 14. The inner tube 14 carries out the task of a conventional silencer assembly, and it has an inner space divided into a plurality of axially spaced partitions communicating thorough axial bores that allow fee passage of the projectile 2.

Fig. 2 shows the silencer device in apposition immediately after firing when the projectile 2 is in the first partition 19 of the inner tube 14. At this phase only the first wave of the released gasses reach the silencer device 10.

In Fig. 5 the situation is shown by a fraction of a thousandth of a second later than the position shown in Fig. 2 when the projectile 2 has just flown out of the silencer device 10. It has been indicated in the drawing that the gasses has passed through the partitions of the inner tube 14 that at as a silencer assembly, but at this phase the gases have not totally filled the chamber 18. Fig. 6 shows a position just a bit later in which the pushing forces of the gasses flowing out with high energy act on the rear face of the inner tube 14 and sides it forward against the biasing force of the coil springs 17. In this position the volume of the chamber 18 behind the inner tube 14 increases substantially compared to its initial value and this decreases correspondingly the pressure and speed of the gas flow. Fig. 7 shows the device in the most forward position limited by the abutting shoulder, when the volume of the chamber 18 is at maximum and as a consequence both the pressure and volume of the gas flow have got decreased in a substantially amount. Thereafter the gasses can get released to the free atmosphere through the axial bore of the inner tube 14, and when the pressure has decreased to the extent that cannot balance the pressure of the coil springs 17, the inner tube 14 will return to the initial position shown in Fig. 1

Reference is made now to Figs. 3 and 4 that show another embodiment of the silencer device 10 according to the present invention. The difference lies in that in the ring-shaped space formed between the rear shoulder 15 of the inner tube 14 and the ring 13 at the front end of the outer tube 12 a ring 20 is arranged that has an axis falling in the axis of the inner tube 14. In the exploded view of Fig. 4 the inner ring 14 can be seen with its shoulder 15, wherein the spring 2 is arranged around the outer surface of the inner ring 14, and the outer tube 12 encircles the spring 20.

In spite of its simple design the silencer device according to the invention is very efficient because it provides a large transitional volume for the released gasses at their site of origin i.e. just after the end of the barrel 6, therefore gasses with substantially decreased pressure and volume will enter the inner tube 14 as a silencer assembly as if this effect was not provided by the substantial volume expansion of the chamber 18. The forward displacement of the inner tube 14 will at the same time reduce the light effect associated with the shooting. Compared to the provided extent of the silencing effect the size of the device is small, especially when it is in initial position, and it has also a decreased weight.

In Fig. 8 a further embodiment of the invention has been shown, wherein the diameter of the outer tube 12 is substantially larger compared to the previous embodiments, therefore it provides sufficient inner space for an intermediate tube 23 for placement between the outer tube 12 and the inner tube 14, which is also guided for axial movement. The diameters of the three tubes 12, 23 and 14 decrease in a stepwise manner and between them there is sufficient space for arranging springs 21 and 22 which press their limiting tubes rearwards i.e. towards the barrel 6.

After shooting the gases coming from the throat of the barrel 6 will push forward both the inner tube 14 and the intermediate tube 23 against their spring-bias, and the space in front of the throat of the barrel will be divided into two large chambers 18a and 18b, wherein the chamber 18b is constituted by the part of the intermediate tube 23 behind the inner tube 14, and the chamber 18a is the space behind the intermediate tube 23. For increasing the size of the outer tube 12 the possibility and space is provided in case of larger firearms such as carbines or guns.

In accordance with the foregoing teaching the silencer device can be created by more telescopic parts, therefore the invention cannot be limited to any one of the exemplary embodiments shown.