Spiral baffle for a firearm suppressor

Abstract

A spiral baffle for a firearm suppressor is disclosed. The spiral baffle includes a projectile passageway surrounding an axis; a helical surface making at least one full turn around said axis; a central portion surrounding said projectile passageway and being situated adjacent thereto, said central portion defining plurality of protrusions extending beyond said helical surface in a first direction parallel to said axis, said protrusions also extending away from said projectile passageway in a second direction away from said axis.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority from U.S. Provisional Patent Application No. 63 / 746,550 filed on Jan. 17, 2025, which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present invention relates to the field of firearm accessories. More particularly, it relates to spiral baffle for a firearm suppressor and a firearm suppressor in which such a spiral baffle is integrated.STATE OF THE ART

[0003] Firearm sound suppressors have existed since the late 19th century, and typically include an outer casing of tubular form, adapted to be attached at the muzzle of a firearm, defining a passage aligned with the bore axis to allow the projectile to pass through and exit the suppressor. In its simplest form, as disclosed in CH5755, the outer casing defines a single expansion chamber for allowing the propellant gases to expand and reduce their pressure before exiting to the atmosphere, reducing the intensity of the sound report produced as the relatively high-pressure gases leaving the muzzle exit into the relatively low-pressure atmosphere.

[0004] From this simple basis, a great variety of more effective suppressors have been developed over the years, typically dividing the inner space within the casing into multiple compartments, in order to slow the expansion of the propellant gases by disrupting their flow and / or forcing the flow to change direction with one or more of baffles, swirl chambers, and so on, which are adapted to disrupt the propellant gas flow such that it exits the suppressor at a lower pressure and velocity than it exited the muzzle.

[0005] One particular arrangement is known as a spiral baffle or a spiral diffuser, examples of which are disclosed in documents DE231957, U.S. Pat. Nos. 1,111,202, 1,341,363,US2024133650 and many others. In its most simple form, such a spiral baffle includes a strip of material in a helical form, typically making several full turns within the suppressor body, and may be formed conventionally by twisting a strip of metal around a former. Such arrangements create relatively low backpressure, since there is a continuous, albeit helical, gas pathway through the suppressor, but have fallen out of favor for use on their own, since their suppressive properties can be limited compared to conventional baffles dividing the interior of the suppressor into discrete chambers. Indeed, it should be noted that spiral baffles may be found in combination with a conventional baffle stack, with the conventional baffles nearest to the firearm muzzle and the spiral baffle situated further therefrom (such as in U.S. Pat. No. 1,111,202 mentioned above), and sometimes spiral baffles are used in an outer chamber, such as a bypass chamber, surrounding a conventional baffle stack, as in documents CN110425929 and CN215864879U.

[0006] The aim of the invention is hence to propose a spiral baffle for a firearm suppressor, in which the above-mentioned disadvantages are at least partially mitigated.DISCLOSURE OF THE INVENTION

[0007] More precisely, the invention relates to a spiral baffle for a firearm suppressor, as defined in independent claim 1. This spiral baffle includes a projectile passageway, i.e. a through opening adapted to permit the passage of a projectile leaving the muzzle of a firearm, surrounding an axis A; at least one helical surface, whether continuous or with interruptions such as ribs, ridges, slots, openings or similar, making at least one full turn, preferably between two and ten turns, further preferably between three and seven turns, around axis A, although any number of turns may be used. It should be noted that said at least one helical surface does not have to be continuous, and may be formed by a plurality of elements attached together. The baffle further including a central portion surrounding said projectile passageway and being situated adjacent thereto, said central portion defining a plurality of protrusions extending beyond said helical surface in a first direction in parallel to axis A, said protrusions also extending away from said projectile passageway in a second direction, obliquely or orthogonally away from axis A. These protrusions may be formed, for instance, as lobes, fingers, teeth, vanes, turbine blades of spiral or other form, or any other convenient form, extending radially, obliquely, on a curve with or against the twist of the helical surface, or in any other convenient manner.

[0008] With the spiral baffle integrated into a firearm suppressor, the presence of said protrusions along the length of the spiral baffle 3 creates considerable flow disruption, not only in respect of gases propagating through the projectile pathway in a similar manner to a lobed baffle of conventional form, but also those passing in a helical manner along the spiral baffle surface because the protrusions act as immovable vanes which resist this portion of the gas flow and have a tendency to create turbulence and slow the flow. Furthermore, the interaction between the gas propagating through the projectile pathway and the gas travelling along the spiral baffle further serves to disrupt the overall gas flow through the spiral baffle since these two flows are acting in different directions and their mixing creates flow disruption. This results in excellent sound reduction without high backpressure and without recourse to a conventional bypass chamber. This may also result in material and weight savings for the same sound reduction performance compared to a conventional reduced backpressure suppressor with a conventional bypass chamber.

[0009] Advantageously, said central portion is hollow, i.e. concave, on its back side, i.e. on its side intended to face away from a firearm muzzle when the spiral baffle is in a service position, i.e. installed in a suppressor mounted on a firearm muzzle. This keeps the weight of the spiral baffle, and the overall suppressor, to a minimum, and saves material during manufacturing compared to a massive central portion.

[0010] Typically, said helical surface is inclined with respect to axis A at an angle between 10° and 80°, preferably between 20° and 60° further preferably between 30° and 50°. Typically, an angle of 30° or 45° is simplest to manufacture.

[0011] Typically, said protrusions are evenly spaced angularly along at least part of the length of said spiral baffle, although they may alternatively be distributed irregularly, and / or the form of the protrusions may vary systematically or randomly from one to the next. In practice between four and eight, preferably between five and seven, protrusions may be provided per full turn of said spiral baffle.

[0012] In an embodiment, said protrusions may be narrower near said projectile pathway and be wider at one or more locations remote from said projectile pathway, although they may be of substantially constant width.

[0013] In another embodiment, the protrusions have their own helical and / or spiral form, such as like vanes on a turbine, of any convenient shape. The twist direction of the protrusion is advantageously in the opposite direction to the twist direction of the helical surface. This further enhances turbulence, leading to further reduction of sound.

[0014] In yet another embodiment, the spiral form of the baffle may have further features such as one or more slots, openings, ridges, ribs, concave dimples, or convex dimples. In the case of convex features such as ribs, ridges or convex dimples, these may be of any height, but would typically be between 0.5 and 15 mm high, and spaced at regular or irregular intervals such as between 1 mm and 20 mm. The height does not need to be the same for each rib or dimple. In the case of ribs, for example, there may be a series of short ribs, and then an occasional taller one.

[0015] Advantageously, a plurality of outer openings are provided in an outer periphery of said helical surface. This causes a portion of the propellant gases to bypass the projectile pathway and pass through the peripheral portion of the helical surface, further creating turbulence, admixture and flow disruption within the spiral baffle, further improving the overall performance of a suppressor including said spiral baffle. Typically, each full turn of the spiral baffle (and hence of said helical surface) includes a plurality of said outer openings. This further helps to reduce the backpressure.

[0016] Advantageously, a plurality of helical ribs are furthermore provided, said helical ribs extending through or adjacent to a plurality of said outer openings. When integrated into a suppressor, the helical ribs will typically extend inwardly from an outer wall of the outer casing of the suppressor. The twist direction of the helical ribs is preferably opposite to that of the helical surface, which helps to disrupt and slow the propellant gas flow in the outer part of the spiral baffle. Typically, between three and twelve, preferably between four and eight, helical ribs are provided, ideally evenly distributed around the helical surface and hence the spiral baffle.

[0017] Advantageously, at least some of said helical ribs are at least partially hollow, i.e. they include a hollow, which minimizes their weight. Preferably, said hollow extends along the full length of said helical rib, providing a bypass effect further reducing backpressure.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further details of the invention will become more apparent upon reading the detailed description in reference to the appended figures, which illustrate:

[0019] FIG. 1: an isometric cutaway view of a firearm suppressor including a first embodiment of a spiral baffle according to the invention;

[0020] FIG. 2: a longitudinal cutaway view of the firearm suppressor of FIG. 1;

[0021] FIG. 3: a transverse cutaway view of the firearm suppressor of FIG. 1; and

[0022] FIG. 4: four cutaway isometric views, and four axial transparent cutaway views, illustrating the development of the first full turn of a suppressor including a second embodiment of a spiral baffle according to the invention.EMBODIMENTS OF THE INVENTION

[0023] FIGS. 1-3 illustrate a nonlimiting example of a firearm suppressor 1 in which a spiral baffle 3 according to the invention is integrated. As is generally known, a firearm suppressor 1 has an outer casing 5, of generally tubular form, with a conveniently-shaped cross-section such as a circle, oval, polygon or similar, extending from a first extremity 7 to a second extremity 9. First extremity 7 is the proximal extremity of the suppressor 1 and is adapted to be attached to a muzzle of a firearm (not illustrated) such as a rifle, shotgun, carbine or similar by a convenient adapter (not illustrated) such as a threaded, quick-detach or other convenient adapter, whereas second extremity 9 is the distal extremity of the suppressor 1 and is provided with an end cap 11, which may be integrally-formed with the outer casing 5, or may be a separate part attached thereto e.g. by threading, screwing, pinning, welding or similar, as is generally known.

[0024] The spiral baffle 3 is situated within the outer casing 5, and includes a helical surface 13, which in this example makes five complete turns along the length of the outer casing 5, although any suitable number of turns between one and ten or even more is also possible, two to five being an optimal compromise. Longer firearms sound suppressors may use more turns. As illustrated, the spiral baffle 3 includes a single helical surface 13 with a single start point, but two or even more start points defining multiple helical surfaces 13 are also possible. It should be noted that the suppressor 1 as illustrated only contains a single spiral baffle 3 according to the invention, however it may be used in combination with other baffles of any convenient form in a baffle stack. Furthermore, the helical surface 13 may be defined by multiple sections of baffle fixed together, and is not to be interpreted as being restricted to a continuous surface on a monolithic spiral baffle 3.

[0025] It should also be noted that the helical surface 13 may be provided with one or more other features such as slots, openings, ridges, ribs, concave or convex dimples, or similar. Particularly of note are ridges extending radially or along a curve, this curve advantageously having a direction of twist that is opposite to the direction of twist of the helical surface 13 itself. In the case of convex features such as ribs, ridges or convex dimples, these may be of any height, but would typically be between 0.5 and 15 mm high, and spaced at regular or irregular intervals such as between 1 mm and 20 mm. The height does not need to be the same for each rib or dimple. In the case of ribs, for example, there may be a series of short ribs, and then an occasional taller one.

[0026] The central portion of spiral baffle 3 includes an opening, defining a projectile pathway 15 along an axis A, of dimensions sufficient to permit a projectile to pass through the spiral baffle 3 without entering into contact therewith.

[0027] In the illustrated embodiment, helical surface 13 is inclined with respect to axis A at an angle between 10° and 80°, preferably between 20° and 60° further preferably between 30° and 50°, such that the outermost portion of the spiral baffle 3 is situated furthest from the first extremity 7 of the suppressor 1, considered in any plane perpendicular to axis A, however it may alternatively be orthogonal thereto. Furthermore, although the angle of inclination of the helical surface 13 and its pitch are constant along the length of the spiral baffle 3, this does not have to be the case, since the angle of inclination and / or the pitch of the twist of the helical surface 13 may vary along said length.

[0028] The central portion 17 of the spiral baffle 3, which is adjacent to the projectile opening 15, extends in two directions, namely from the helical surface 13 in a first direction towards the first extremity 7 of the suppressor 1, and in a second direction, from the projectile passageway 15 away from axis A. This central portion 17 takes the form of a plurality of protrusions 19 extending outwardly from the projectile passageway 15, according to said first and second directions. The central portion 17 hence sits proud of the helical surface 13, extending towards the first extremity 7. In this embodiment, the protrusions 19 are shaped as lobes.

[0029] The summits of the protrusions 19 in the illustrated embodiment are flat, and are inclined in the same manner as helical surface 13 and with the same angle of inclination with respect to axis A, however they may be rounded, and may be inclined at a different oblique angle to the helical surface 13 or may extend perpendicularly with respect to axis A. The protrusions 19 as illustrated have a generally lightbulb shape, with a thinner root or waist proximate to the projectile passageway 15, and a wider, rounded outer portion, but this is not to be construed as limiting, since the protrusions may be shaped as fingers, ridges, teeth, vanes, blades or similar of any convenient shape extending radially, obliquely, or even in a curved manner with or against the curve of the helical surface 13. In a particularly advantageous non-illustrated embodiment, the protrusions 19 have a helical and / or spiral form, for instance being shaped like turbine blades, with a twist direction opposite to the twist direction of the helical surface. In such a case, the cross-sectional shape of the individual blades may be triangular, elongated, finger-like, blade-like or any other convenient shape.

[0030] In order to save weight and material, the central portion 17 is hollow and concave on its side directed towards the second extremity 9 (i.e. its back side given the usual understanding of “front” being the upstream side and “back” being the downstream side of the spiral baffle 3 when in use), however this is not obligatory and the central portion 17 may be configured of relatively thick material compared to the conical surface 13, and may indeed be of massive, solid construction.

[0031] In the embodiment of FIGS. 1-3, each full turn of the spiral baffle 3 includes six protrusions 19, which are hence separated angularly one from the next by 60° of twist of the spiral baffle 3. However, other numbers of protrusions 19 per turn of the spiral baffle 3 are possible, whether this number is an integer number or a non-integer number. Typically, between 5 and 8 protrusions 19 per turn would be used.

[0032] Having protrusions 19 along the length of the spiral baffle 3 creates considerable flow disruption, not only in respect of gases propagating through the projectile pathway 15 in a similar manner to a star baffle of conventional form, but also those passing in a helical manner along the spiral baffle 3 around the projectile pathway 15, since they act as immovable vanes which resist this portion of the gas flow and have a tendency to create turbulence and slow the flow. Furthermore, the interaction between the gas propagating through the projectile pathway 15 and the gas travelling along the spiral baffle 3 further serves to disrupt the overall gas flow towards the second extremity 9 of the suppressor 1 since these two flows are acting in different directions and their mixing creates flow disruption. This results in excellent sound reduction without a high backpressure, without recourse to a conventional bypass chamber, which may also result in material and weight savings for the same sound reduction performance.

[0033] The arrangement as illustrated has further, optional features which further help to enhance the suppressor 1's performance.

[0034] Firstly, the outer periphery of the helical surface 13 is provided with a plurality of outer openings 21 of any convenient form, distributed along at least a portion of its length. These outer openings 21 permit a portion of the propellant gases to bypass not only the projectile pathway but also the helical pathway defined by the helical surface 13, allowing them to pass through the peripheral portion of the helical surface 13, further creating turbulence, admixture and flow disruption, and likely also having a positive impact in reducing backpressure. As illustrated, these outer openings 21 are evenly spaced along the helical surface 13 with six openings 21 per rotation of the helical surface 13, but different numbers are possible and they may also be unevenly spaced. This bypassing effect further reduces backpressure, again without recourse to a conventional bypass chamber.

[0035] In order to yet further increase the flow disruption through the outer openings 21, a plurality of helical ribs 23 are provided, extending inwardly from the inner wall of the outer casing 5. In the illustrated embodiment, six evenly-spaced helical ribs 23 are provided, which twist around axis A in the opposite rotational direction to the helical surface 13 and which pass through or adjacent to the outer openings 21, which are positioned accordingly along the periphery of the helical surface 13. Naturally, other numbers of helical ribs 23 can be provided, e.g. between three and twelve, typically between four and eight. As illustrated, the edge of each outer opening 21 is integrated with the helical rib 23 which passes therethrough, which is a particularly strong arrangement, however this latter can also be arranged so as to be out of contact with the helical surface 13. These helical ribs 23 serve to slow and disrupt the outer portion of the propellant gas flow, notably since their direction of twist opposes that of the helical surface 13.

[0036] In order to permit the lightest possible construction, each helical rib 23 is optionally hollow, by virtue of being provided with a hollow 25, here illustrated as a through-passageway leading along the entirety of each helical rib 23 from one end of the interior of the outer casing 5 to the other. Provided that the hollows 25 remain unblocked, they permit a bypass effect for a relatively small proportion of the propellant gas to bypass the spiral baffle 3, and hence reduce backpressure further. It is also possible to block each end of the hollows 25 to prevent this gas flow and thereby prevent the hollows 25 from being fouled, and it is also possible for the hollows 25 to be non-continuous along the length of the helical ribs 23, i.e. be arranged in hollow segments separated by solid walls.

[0037] However, it should be noted that helical ribs 23 are optional and hence do not have to be present. It should also be noted that, in the case in which the spiral baffle 3 is not integrally formed with the outer casing 5, they may be formed integrally with the helical surface 13 or attached thereto, with the entire assembly of the thus-formed spiral baffle, complete with helical ribs 23, being inserted into a separate outer casing 5 and being fixed therein.

[0038] Although the embodiment of FIGS. 1-3 has a central portion 17 with protrusions 19 which are of invariant shape along the length of the spiral baffle 3, the shape and / or disposition of the protrusions 19 may vary, the protrusions may be discontinuous, and indeed all manner of variations are possible.

[0039] FIG. 4 illustrates such an example, illustrating in four cutaway views and four transparent views with the cut surface illustrated in black, dividing the first full turn of a spiral baffle 3 into several sections, starting from its extremity closest to the first extremity 7 of the suppressor 1, and hence closest to the firearm muzzle when the suppressor 1 is installed. Only the reference signs mentioned in specific reference to FIG. 4 are reproduced thereupon, in order to avoid overloading them.

[0040] In this embodiment, the protrusions 19 are again shaped as lobes. The central portion 17 is initially unlobed, and forms a ramped portion 25 which, as the first turn of the spiral baffle 3 progresses (from left to right on FIG. 4), is blended into the lobes 19 which are of rounded U-shaped section, without a waist or thinner root, unlike those of FIGS. 1-3. This ramped portion 25 is sturdier than the lobe-shaped protrusions 19, and hence is more resistant to erosion from the propellant gases leaving the muzzle of the firearm, and serves a similar role to a reinforced blast baffle in a conventional baffle construction.

[0041] In terms of manufacturing, the blast baffle 3 is most suitably manufactured by additive manufacturing (i.e. 3D printing), particularly by selective laser sintering, selective laser melting or similar, which is capable of forming very precise shapes that are difficult or impossible to create by conventional machining. This approach also has the advantage of being compatible with an integrated construction, where the spiral baffle 3 is integral with the outer casing 5. Likewise, the end cap 11 may be a separate part, or integrally-formed with the outer casing 5. However, it may also be manufactured by casting, particularly investment casting, in one or more parts.

[0042] In terms of materials, the full range of conventional materials (e.g. steels, aluminium, titanium, Inconel etc.) can be used for the blast baffle 3.

[0043] Although the invention has been described in terms of specific embodiments, variations thereto are possible without departing from the scope of the appended claims.

Claims

1. A spiral baffle for a firearm suppressor, comprising:a projectile passageway surrounding an axis;a helical surface making at least one full turn around the axis;a central portion surrounding the projectile passageway and being situated adjacent thereto, the central portion defining a plurality of protrusions extending beyond the helical surface in a first direction parallel to the axis, the plurality of protrusions also extending away from the projectile passageway in a second direction away from the axis.

2. The spiral baffle of claim 1, wherein the helical surface makes between two and ten turns around the axis.

3. The spiral baffle of claim 1, wherein the helical surface makes between three and seven turns around the axis.

4. The spiral baffle of claim 1, wherein the central portion is hollow on a side intended to face away from a firearm muzzle when the spiral baffle is in a service position.

5. The spiral baffle of claim 1, wherein the helical surface is inclined with respect to the axis at an angle between 10° and 80°.

6. The spiral baffle of claim 1, wherein the helical surface is inclined with respect to the axis at angle between 20° and 60°.

7. The spiral baffle of claim 1, wherein the helical surface is inclined with respect to the axis at an angle between 30° and 50°.

8. The spiral baffle of claim 1, wherein the plurality of protrusions are evenly spaced along at least a portion of a length of the spiral baffle.

9. The spiral baffle of claim 1, wherein the plurality of protrusions include between four and eight protrusions per full turn of the spiral baffle.

10. The spiral baffle of claim 1, wherein the plurality of protrusions include between five and seven protrusions per full turn of the spiral baffle.

11. The spiral baffle of claim 1, wherein the plurality of protrusions are shaped as lobes which are narrower adjacent to the projectile passageway and wider at least one location remote from the projectile passageway.

12. The spiral baffle of claim 1, wherein the plurality of protrusions have at least one of a spiral and helical form, the spiral and helical form having a direction of twist which is opposite to that of the helical surface.

13. The spiral baffle of claim 1, further comprising at least one or more slots, openings, ridges, ribs, concave dimples, or convex dimples.

14. The spiral baffle of claim 1, wherein a plurality of outer openings are provided in an outer periphery of the helical surface.

15. The spiral baffle of claim 1, wherein a plurality of outer openings are provided for each full turn of the spiral baffle.

16. The spiral baffle of claim 15, further comprising a plurality of helical ribs, the plurality of helical ribs extending through or adjacent to the plurality of outer openings.

17. The spiral baffle of claim 16, wherein at least some of the helical ribs comprise a hollow, the hollow preferably extending along a full length of the helical rib.

18. The spiral baffle of claim 16, wherein the plurality of helical ribs have an opposite direction of twist around the axis to that of the helical surface.

19. The spiral baffle of claim 16, wherein the plurality of helical ribs includes between three and twelve helical ribs.

20. The spiral baffle of claim 16, wherein the plurality of helical ribs includes between four and eight helical ribs.

21. The spiral baffle of claim 16, wherein the plurality of helical ribs are evenly distributed around the helical surface.

22. A firearm suppressor, comprising:an outer housing;a spiral baffle contained in the outer housing, the spiral baffle including:a projectile passageway surrounding an axis;a helical surface making at least one full turn around the axis;a central portion surrounding the projectile passageway and being situated adjacent thereto, the central portion defining a plurality of protrusions extending beyond the helical surface in a first direction parallel to the axis, the plurality of protrusions also extending away from the projectile passageway in a second direction away from the axis.

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