Patent Publication Number: US-11391532-B2

Title: Adapter for mounting an accessory on a firearm

Description:
TECHNICAL FIELD 
     The present disclosure relates to the mounting of accessories on firearms. More particularly, the disclosure relates to adapters for mounting an accessory on a firearm, such as an assault rifle. 
     BACKGROUND 
     Firearm accessories, or accessory parts, can include any of a wide variety of devices designed to couple with or attach to a firearm. Some common firearm accessories include sights, scopes, illumination sources, sound suppressors or silencers, muzzle brakes, and flash dampers, among others. Such accessories may require an accessory adapter in order to mount the accessory to the intended firearm. 
     Published patent application US 2019/072354 A1 (hereby incorporated by reference for all purposes) discloses an adapter that has considerable length in the direction of the barrel, is mounted and fixed on a sheath of a firearm with protrusions. A threaded part on the front end of the adapter cooperates with a threaded part on the rear end of the accessory. This system is voluminous and requires rotation of the adapter to attach, which can be cumbersome and undesirable when in the field. 
     Published patent application US 2013/133976 A1 (hereby incorporated by reference for all purposes) discloses a silencer which is mounted directly at the front end of a barrel without a sheath and with the help of a bayonet-like attachment mechanism. 
     When fired in fully automatic mode, contemporary assault rifles can have a firing rate of several hundred rounds per minute. Under such conditions, rapid dissipation of the generated heat is required, and was accomplished by the attachment of a variety of different sheaths on the barrels of such rifles. For example, the front stocks of AR-15-style rifles are frequently designed as perforated and usually two-part “handguards.” These handguards are arranged so as to be at a distance from the barrel, protecting the user from direct contact with the hot barrel, while simultaneously allowing airflow to enhance cooling. Silencers, also incorporated devices for blocking heat transport to the outer surface, and such covers often rested directly on the silencer. 
     When an accessory is to be mounted to the barrel of a firearm, two problems occur: First, any attachment of an accessory to the barrel end increases the problem of heat dissipation from the barrel, since the escape of gas into the surroundings at the end of the barrel can no longer take place unimpeded, leading to rapid and significant heating of the accessory. Particularly in the case of silencers, which operate by reducing the speed of emerging combustion gases to below the speed of sound, it is difficult to conduct away the energy, which is converted into heat in the process. This also applies, to an only slightly lesser extent, for other muzzle attachments. 
     Although the following discussion is in the context of an accessory silencer, this is merely used as an example in order to more clearly explain the attachment of an accessory. In order to cover a silencer to the outside, both to protect the user and in order that an adversary cannot easily identify the “thermal signal” of the silencer after one shot, or at the latest after a plurality of shots, a silencer should preferably be thermally shielded with respect to the surroundings. In the prior art, a suitable cover may be fastened directly to the silencer and referred to as the “suppressor cover.” A cover of this kind which is directly fastened to a silencer, a muzzle brake, or the like, increases the mass and weight that acts on the coupling point to the barrel, as a result of which the precision of the weapon suffers, as does the mechanical load thereof. 
     What is needed is an improved attachment (mounting) of accessories such as shields of silencers, muzzle brakes, flash hiders (also referred to as “flash dampers”), lights, and other accessories on the weapon. As previously explained, in the prior art said accessory components are generally fastened directly at the front of the barrel, on the muzzle thereof. Such attachments would benefit from improved support and/or retention of a heat shield surrounding the barrel. 
     SUMMARY 
     The present invention includes adapters for mounting an accessory, or accessory part, to a firearm; firearm sheaths compatible with such adapters, and accessories configured to be compatible with such adapters. 
     In one embodiment the invention includes an adapter for mounting an accessory on a sheath of a firearm, where the firearm defines a barrel axis, and the adapter includes at least two portions that are arranged adjacently along the barrel axis; the at least two portions including a rear portion configured to be adjacent the firearm and formed so as to be geometrically complementary to at least a portion of a front end of the sheath; and a front portion configured to be adjacent the accessory and including a cylindrical coupling surface on an outside of the front portion and configured to couple with the accessory. The adapter is substantially annular or tubular in shape, and includes at least one bayonet extension on the cylindrical coupling surface that projects radially outwards, and at least one spring-loaded push button on the coupling surface. 
     In one embodiment, the invention includes a sheath for a barrel of a firearm, where the firearm defines a barrel axis, and the sheath includes a sheath front portion that is geometrically complementary to a rear portion of an accessory adapter; where the adapter includes at least two portions that are arranged adjacently along the barrel axis; the at least two portions including a rear portion configured to be adjacent the firearm and formed so as to be geometrically complementary to at least the front portion of the sheath; and a front portion configured to be adjacent an accessory and including a cylindrical coupling surface on an outside of the front portion and configured to couple with the accessory; and where the adapter is substantially annular or tubular in shape, and includes at least one bayonet extension on the cylindrical coupling surface that projects radially outwards, and at least one spring-loaded push button on the coupling surface. 
     In one embodiment, the invention includes a sheath for a barrel of a firearm, where the firearm defines a barrel axis, the sheath including a sheath front region, and a handguard. The front portion of the sheath includes a front portion of an accessory adapter that is formed integrally on the handguard, the front portion of the accessory adapter being further configured to be adjacent an accessory and including a cylindrical coupling surface on an outside of the front portion and configured to couple with the accessory; where the accessory adapter is substantially annular or tubular in shape, and includes at least one bayonet extension on the cylindrical coupling surface that projects radially outwards, and at least one spring-loaded push button on the coupling surface. 
     In one embodiment, the invention includes a firearm accessory, including a shroud formed on an end region of the accessory, on a weapon side of the accessory, configured to couple with an accessory adapter or a sheath; where the accessory adapter includes at least two portions that are arranged adjacently along a barrel axis of a firearm; the at least two portions including a rear portion configured to be adjacent the firearm and formed so as to be geometrically complementary to at least a portion of a front end of the sheath; and a front portion configured to be adjacent the accessory and including a cylindrical coupling surface on an outside of the front portion and configured to couple with the accessory. The accessory adapter is substantially annular or tubular in shape, and includes at least one bayonet extension on the cylindrical coupling surface that projects radially outwards, and at least one spring-loaded push button on the coupling surface. The front portion of the sheath includes a front portion of the accessory adapter that is formed integrally on the handguard, the front portion of the accessory adapter being further configured to be adjacent the accessory and including a cylindrical coupling surface on an outside of the front portion and configured to couple with the accessory. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a side view of an exemplary firearm equipped in a manner according to the present disclosure.  FIG. 1B  is a perspective view of an accessory part on an exemplary sheath, consistent with the present disclosure. 
         FIG. 2  is an exploded view of the parts of the firearm of  FIG. 1A . 
         FIG. 3  shows an exemplary adapter on a sheath in an enlarged detail. 
         FIG. 4  is a perspective exploded view of an exemplary adapter of the present disclosure. 
         FIG. 5A  is a cross section view through the barrel axis in the mounting region of the firearm of  FIG. 1A .  FIG. 5B  is an enlarged detail of the cross section view of  FIG. 5A . 
         FIG. 6A  is a cross section perpendicular to the barrel axis of the firearm of  FIG. 1A .  FIG. 6B  is a cross section perpendicular to the barrel axis of the firearm of  FIG. 1A  in a different locking position. 
     
    
    
     DETAILED DESCRIPTION 
     In the context of the disclosed invention, reference may be made, by way of simplification, to a sheath, a handguard, and various other components such as a barrel, and/or handguard clamp also being included. Reference may also made, by way of simplification, to the front stock, this likewise being intended to specify a synonym for the sheath. 
     In the light of the present disclosure, a person having ordinary skill in the art and the benefit of the disclosure would well understand how to integrate presently disclosed adapter, if necessary, with the disclosed coupling connection, in a specifically-designed sheath, or a correspondingly-adapted handguard. As an example, the bayonet joint could also be formed directly on the sheath of the barrel, as a result of which the mechanical stability can be further improved. 
     As a central feature, an adapter for attaching (any desired) accessory part can be provided on the handguard, the barrel sheath. With respect to the firearm the adapter is geometrically adapted to the sheath, and it is also geometrically adapted to and can be coupled to the accessory part. The coupling connection between the adapter and the accessory part is preferably designed as a bayonet joint, and can comprise an additional securing means, such as one or more push buttons. The geometry with respect to the weapon is specified by the usually already existing sheath, and does not require any detailed explanation. 
     For the purposes of overview,  FIG. 1A  is a side view of a weapon equipped according to the present disclosure comprising a sheath (“handguard assembly”)  20 , a housing (“receiver”)  12 , a stock  13 , a grip  10 , and an accessory part  40 , generally denoted merely “accessory” in the following, that is fastened to the sheath  20 . 
     The selected embodiment of the accessory part  40  is based on a shield of a silencer and is intentionally shown in a very simplified manner. In the light of the disclosure a person skilled in the art can transfer, mutatis mutandis, the coupling illustrated by the present disclosure of an accessory part  40 , such as lamps, sights or other accessories. For this reason, the accessory part  40  is shown as a simple cylinder, without possible further design features, and the necessary details are specified only in the region of the mounting. This is due to the fact that, with the exception of said features that are relevant for the fastening, the design of the accessory  40  is not a critical aspect of the present disclosure. 
       FIG. 1B  is a schematic oblique view of an adapted accessory part  40  on the sheath  20 . In this view, the coupling of the accessory part can be identified by a sliding and rotary connection in the manner of a “bayonet attachment,” which is formed by bayonet locks  341  and correspondingly formed bayonet notches  441  of the accessory part  40 . 
     Furthermore,  FIG. 1B  shows a preferred embodiment, in which a spring-loaded push button  310  engages, in the radial direction towards the outside, in corresponding holes  425 , for the purpose of securing against unintentional rotation of the accessory part  40 . 
     Moreover,  FIG. 1B , in conjunction with  FIGS. 3, 4 and 6 , shows a particularly preferred embodiment, according to which the adapter  30  comprises, on the front portion  34 , at least one adapter opening  344  that preferably adjoins the at least one bayonet lock  341 , in the peripheral direction. This forms inter alia additional ventilation holes in the coupling region. 
     The accessory part  40  comprises a plurality of L-shaped bayonet recesses  430  which originate from the edge of the accessory  40  facing the weapon. The bayonet recesses  430  can in principle also be formed so as to be arcuate. Although this embodiment is not shown, a person skilled in the art having the benefit of the present disclosure would understand that an arcuate design makes it possible for bracing to be achieved in the direction of the adapter  30 , by means of the turning movement of the accessory part  40 . 
     In the preferred embodiment, the at least one bayonet notch  430  is L-shaped, comprising a first limb which extends in parallel with the barrel axis  140 , proceeding from the edge of the end on the weapon side, and a second limb which is designed so as to extend in the peripheral direction, following said first limb. 
       FIG. 2  is an exploded view of the components shown in  FIG. 1B . Said components can, in principle, also be formed integrally on the handguard  20  in order to form the front stock,  FIG. 2  showing an example for a plurality of components that form the sheath  20 . 
     In addition to the handguard  210  just mentioned, or the sheath  20 ,  FIG. 2  shows a heat shield  220  which is intended for being accommodated inside the handguard  210 . Heat shield guide extensions  220  can be seen laterally, on said heat shield  220 , which extensions are used for guidance or mounting in the handguard  210 . Upon closer inspection of these illustrations, it is possible to see a plurality of guides  231  on the inside of the handguard  210 . The heat shield  220  can be inserted along said guides  231  and is guided using the guide extensions  230  and retained at a defined distance from the barrel  10  or the handguard  210 , as is particularly clear in conjunction with  FIGS. 3 and 5  and will be explained in further detail in the following. Said guides  231  can be formed as notches or other functionally equivalent protruding double strips, in order to form a corresponding rest and guide for the guide extensions  230 . 
     Furthermore,  FIG. 2  shows a plurality of screws  332  which are used for fastening the adapter  30  to the handguard  210 , in the region of the rear portion  32 . 
     In a preferred embodiment, viewed from the outside the handguard  210  comprises a “right-hand thread,” and the screws  332  are formed in the stock as a type of countersunk bolt comprising a tool receptacle, e.g. a hex key or Torx. In this manner, the screws  332  can be screwed onto the handguard  210  in a manner penetrating outwards, from the inside of the adapter  30 , in the radial direction, in the region of the rear portion  32 , in that a screwdriver is moved to the “left,” from the outside, and thus draws the adapter  30  “outwards” on the handguard  210 , in the region of the contact face  333  thereof. This “inverted screw” method is advantageous in that no screw heads are located on the outside, and the outer contour of the handguard  210  remains unaffected. Furthermore, this is a relatively loss-proof manner of attaching the screws. 
     As can be seen in  FIG. 3 , which shows the adapter  30 , mounted on the sheath  20 , obliquely towards the front, depending on the perspective, the adapter  30  preferably has a generally annular or generally tubular structure. The front portion  34  is designed so as to be substantially annular, for the purpose of attaching the accessory  40 , while the shape of the rear portion  32  recreates the inner contour of the handguard  210  that is to be contacted, as is clear in conjunction with  FIG. 4 . When considering  FIG. 4 , it quickly becomes clear to a person skilled in the art that forming extensions that protrude from the front portion  34  on the weapon side would be sufficient for ensuring good attachment to the handguard  210 . 
       FIG. 4  shows that the rear portion  32  has smaller dimensions in the radial direction  323 , proceeding from the barrel axis  140  to the contact surfaces  333  which, in the mounted state, are in planar abutment on complementary inner surfaces of the handguard  210 . 
     The radial dimensions  323 ,  343  can also be approximately the same, or, in exceptional cases, it is even possible for the rear radial distance  323  from the contact surface  333  to be smaller than the front radial distance  343  from the coupling surface  342 . Owing to the shape of the handguard  210  and the accessory  40 , it is left to a person skilled in the art to optimally adjust the dimensions, having the knowledge provided by the disclosure. 
     The examples shown illustrate the preferred stepped design of the adapter  30 , the distance, in the radial direction  343 , from the coupling surface  342 , being designed so as to be larger in the front portion  34  than in the rear portion  32 . This is very clear in conjunction with  FIG. 3 , and makes it possible for the outer contour of the entire weapon, in the front region, i.e. the accessory part  40  and the handguard assembly  20  (=sheath), to be designed so at to be at least substantially flush, on the upper face. The significant advantage of this is that a sight, optical/thermal aiming devices, and the like, do not protrude beyond the sight line of the upper edge of the weapon. A further advantage of the stepped structure of the adapter  30  is that, when mounting the adapter  30  on the handguard  210 , the lateral clamping pin holes  316  which are clearly visible in  FIG. 4  are covered, and it is thus possible to reduce the risk of undesired release during use. 
     In general, the coupling surface  342  is in the shape of portions of lateral surfaces of at least one circular cylinder, having the barrel axis  140  as the center of the circle, and, when the accessory  40  is mounted, is in planar contact with at least one inner surface of the accessory  40  which is formed as a counter-coupling surface  442 . In this case, planar abutment or planar contact are to be seen and understood in technical, and not mathematical, terms. 
     In the region of the coupling or counter-coupling surfaces  342 ,  442 , the accessory part  40  and the adapter  30  comprise a bayonet attachment, which is known per se, as can be clearly seen in particular in  FIG. 2 . In this manner, the accessory part  40  can be easily plugged and twisted onto the adapter  30 , without the muzzle attachment  111  ( FIG. 5A ), a silencer in the embodiment shown, contacting this. It is of course possible to provide supports if desired. 
     In a particularly preferred embodiment, a plurality of adapter openings  344  is formed on the front portion  34  of the adapter  30 , which openings are arranged in the barrel direction  140  and/or peripheral direction such that, when the accessory part  40  is coupled, i.e. in the closed state of the bayonet attachment, at least a portion of the bayonet notch  441  and the adapter openings  344  are arranged one above the other. This situation can be seen very clearly in  FIG. 1B  and in  FIG. 6 , and provides better ventilation of the coupling region. As explained in the following, improved ventilation of the accessory part is also possible. 
     Furthermore, it is particularly preferable to arrange at least two adapter openings  344 , which are each arranged at an angle of at least 15° with respect to an imaginary line upwards, in the vertical direction. It is also possible for a plurality of adapter openings  344  to be formed over the periphery, in particular on the underside, for improved air supply, although the upper region, when the firearm is held horizontally should not be penetrated by an adapter opening  344 . This arrangement of the adapter openings  344  is suitable for minimizing what is known as the “mirage effect,” i.e. the turbulence of heated air, which can be disadvantageous when looking through a sight. 
     The mounting is preferably fixed, as shown, by means of at least one, preferably two, spring-loaded push buttons  310 . Said buttons are pre-loaded outwards, in the radial direction, by means of at least one spring  311 , and can latch into locking holes  425  in the accessory  40 , when the bayonet latching is completed by engagement and twisting of the bayonet extensions  341  into the bayonet notches  441 . The locking is released by pushing in the push buttons  310 , and the accessory  40  can be easily removed by means of rotation and removal of the sheath  20  or the adapter  30 . 
     As can be seen in  FIG. 4 , it is also possible for two springs  331 , located in spring bores, to be provided per push button  310 , between which springs (in the mounted state) a slot  312  oriented so as to be in parallel with the barrel bore axis, is arranged. Said slot is designed so as to be elongate in the radial direction (with respect to the barrel bore axis), and a pin, preferably a clamping pin  315 , protrudes into said slot, which pin limits the radial mobility of the push button  310  on both sides. In this way, the radial deflection of the push button  310  can take place within limits, and mounting/dismantling of the accessory  40  can be carried out essentially without tools. 
     In accordance with the demands, the adapter  30  is fastened to the sheath  20  by the existing sheath, but in any case preferably in the engagement region of the contact surface(s)  333  by means of screws  332 . Said screws pass through the screw holes  331 , as explained above with reference to the description of  FIG. 2 , and, together with the contact surfaces  333  establish a mechanically reliable connection between the two components. Guides  330  are provided for a heat shield  220  that can optionally be used, as described above. 
     In this manner according to the disclosed invention, the problems of the prior art are solved because all forces and moments which act on the accessory  40  or arise due to the accessory  40  (inert forces) are transferred not to the barrel  10 , but instead directly to the sheath  20  (“handguard assembly”). 
     A further very positive effect of this mounting according is made clear by the combination of  FIGS. 5 and 6 . The annular and stepped structure of the adapter  30  makes it possible for air to flow in from the outside, through the handguard  210 , and to be conducted past, in or on the muzzle attachment  111 , so as to pass through the adapter  30  in a substantially axial and/or radial manner. 
       FIGS. 5A and 5B  show, by way of example, a silencer as the muzzle attachment  111 , which is mounted directly on the muzzle  11 . Therefore, a silencer cover (“suppressor cover”) is shown as the accessory part  40 , which comprises a shroud (“cover”)  410  which comprises a stop  421  on the front end thereof. As a result, when the bayonet attachment  341 ,  441  is latched in, a filling  420 , which is optionally provided and may for example be an insulating jacket consisting of fiberglass or the like, is clamped against the adapter  30 . In this case, an (air) gap  50  remains between the shroud  410  or the filling  420 , allowing for an “air draft” past the silencer. The measures set out allow for more efficient cooling than in the prior art, and delay the heating of the cover or shield of the silencer, as a result of which the thermal signature is reduced. 
     Furthermore, as is clear from the combination of  FIGS. 3, 4, and 6 , the substantially tubular structure of the adapter makes it possible for the connection space  52  between the adapter  30  and the barrel  10  to remain free. Furthermore, it is clear from  FIG. 5 b    that the heated air at the barrel  10  is guided in the intermediate space  51  to the heat shield  220 . The supply air from “outside” through the handguard  210  makes it possible to reduce heat accumulation in the connection space  52 , leading to an increase in the cooling effect at the barrel  10  and delaying heating of the handguard  210 . 
     The specified supply of air can, as explained above, be supplemented by the function of the adapter openings  344  which are possibly provided and are arranged in an optimal manner. 
       FIGS. 6A and 6B  are cross sections perpendicular (normal) to the barrel axis  140 , through the adapter  30 , in the fixed position of the accessory  40 , in  FIG. 6A , and following placement, but prior to twisting or locking, of the bayonet attachment  341 ,  441 , in  FIG. 6B . 
     Taking into account the explanations above, in particular relating to  FIG. 2 , a particularly effective solution simultaneously solves the heat dissipation problem for the barrel  10 , in one embodiment of the invention, by a corresponding shape of the adapter  30 .  FIG. 3  is an oblique view of the adapter  30  fastened to the sheath  20 . Inside the handguard  210  a heat shield  220  is arranged, which is shown in  FIG. 2  in the state ready for insertion. Said heat shield  220  has, as intended, only a few contact points or lines, in the form of guide extensions  230 , which contact the sheath  210  on the inside thereof, in guides  231  provided therefor. In this embodiment, the adapter  30  comprises the already mentioned separate shield guides (“heat shield guide”)  330  ( FIG. 3 ,  FIG. 4 ), which optionally receive the front(most) guide extensions  230 . As a result, when the adapter  30  is mounted on the sheath (handguard)  210 , the heat shield  220  is also oriented and positioned, in all directions (barrel direction, axial direction such that the barrel  1  is not contacted, and such that, when the weapon is moved, rattling of the heat shield  220  in the sheath  210  can be reduced. 
     A number of additional aspects and features of the disclosed adapter, sheaths, and accessories are presented here without limitation as a series of paragraphs, some or all of which may be alphanumerically designated for clarity and efficiency. Each of these paragraphs can be combined with one or more other paragraphs, and/or with disclosure from elsewhere in this application, in any suitable manner. Some of the paragraphs below expressly refer to and further limit other paragraphs, providing without limitation examples of some of the suitable combinations. 
     A1. Adapter ( 30 ) for mounting an accessory part ( 40 ) on a sheath ( 20 ) of an in particular automatic firearm, comprising a barrel axis ( 140 ), whereby the adapter ( 30 ) is substantially annular or tubular in shape, and comprises at least two portions ( 32 ,  34 ) that are arranged adjacently along the barrel axis ( 140 ), a rear portion ( 32 ) being formed, on the weapon side, so as to be geometrically complementary to the front end of the sheath ( 20 ), at least in part, and preferably such that it can be fastened thereto by means of screws ( 332 ), and a front portion ( 34 ) comprising a cylindrical coupling surface ( 342 ) on the outside thereof, for coupling of the accessory part ( 40 ), characterized in that at least one bayonet extension ( 341 ) being provided on the coupling surface ( 342 ) so as to project radially outwards, and in that at least one, preferably two, spring-loaded push button(s) ( 310 ), which are diametrically opposing with respect to the barrel bore axis ( 140 ), is/are provided on the coupling surface ( 342 ). 
     A2. Adapter ( 30 ) according to paragraph A1, characterized in that at least one recess for a push button ( 310 ) is provided on the coupling surface ( 342 ), which recess is penetrated by a clamping pin hole ( 316 ) that is oriented so as to be in parallel with the barrel axis ( 140 ). 
     A3. Adapter ( 30 ) according to paragraph A2, characterized in that the at least one push button ( 310 ) comprises a slot ( 312 ) for inserting a pin ( 315 ). 
     A4. Adapter ( 30 ) according to any of the preceding paragraphs, characterized in that the rear portion ( 32 ) is designed so as to be radially stepped from the front portion ( 34 ). 
     A5. Adapter ( 30 ) according to paragraph A3, characterized in that the rear portion ( 32 ) has smaller radial dimensions than the front portion ( 34 ). 
     A6. Adapter ( 30 ) according to any of the preceding paragraphs, characterized in that the rear portion ( 32 ) comprises at least two holes ( 331 ) for receiving the screwing of screws ( 332 ) in the handguard ( 210 ). 
     A7. Adapter ( 30 ) according to any of the preceding paragraphs, characterized in that two heat shield guides ( 330 ) for receiving heat shield guide extensions ( 230 ) of a heat shield ( 220 ) are formed on the rear portion ( 32 ). 
     A8. Adapter ( 30 ) according to any of the preceding paragraphs, characterized in that the front portion ( 34 ) comprises at least one adapter opening ( 344 ) which is preferably adjacent to the at least one bayonet extension ( 341 ) in the peripheral direction. 
     A9. Adapter ( 30 ) according to paragraph  8 , characterized in that at least two adapter openings ( 344 ) are each formed so as to be at least 15° with respect to an imagined line extending upwards in the vertical direction. 
     A10. Sheath ( 20 ) of the barrel ( 10 ) fora firearm comprising a barrel axis ( 140 ), characterized in that the sheath ( 20 ) comprises, in the front end region, a front portion being geometrically complementary to the rear portion ( 32 ) of an adapter ( 30 ) according to any of the preceding paragraphs, and preferably such that it can be fastened thereto by means of screws ( 332 ). 
     A11. Sheath ( 20 ) according to paragraph A10, characterized in that the inside of the handguard ( 210 ) comprises guides ( 231 ) that are designed so as to be substantially complementary in shape to the heat shield guide extensions ( 230 ) of a heat shield ( 220 ). 
     A12. Sheath ( 20 ) of the barrel ( 10 ) fora firearm comprising a barrel axis ( 140 ), characterized in that its front region has the front portion ( 34 ) of the adapter ( 30 ) formed integrally on the handguard ( 210 ). 
     A13. Accessory part ( 40 ), in particular shield of a silencer, characterized in that a shroud ( 410 ) is formed on the end region thereof, on the weapon side, for coupling to an adapter ( 30 ) according to any of paragraphs A1 to A9, or a sheath ( 20 ) according to paragraph A12. 
     A14. Accessory part ( 40 ) according to paragraph A13, characterized in that a circular cylindrical counter-coupling surface ( 442 ) for coupling to the coupling surface ( 342 ) of the adapter ( 30 ) is formed, which counter-coupling surface comprises at least one, preferably L-shaped, bayonet notch ( 441 ). 
     A15. Accessory part ( 40 ) according to paragraph A14, characterized in that the at least one bayonet notch ( 441 ) comprises a first limb which extends in parallel with the barrel axis ( 140 ), proceeding from the edge of the end on the weapon side, and a second limb which is designed so as to extend in the peripheral direction, following said first limb. 
     A16. Accessory part ( 40 ) according to any of paragraphs A13 to A15, characterized in that at least one, preferably two, locking hole(s) ( 425 ) corresponding to at least one push button ( 310 ) is/are formed. 
     The disclosed invention is not restricted to the exemplary embodiments that are shown and described, but can instead be adapted and designed by a skilled artisan in a different manner. In particular, the invention relates not only to an accessory part  40  that is designed according to the disclosure, but also to the adapter  30  per se, and also a weapon provided with an adapter of this kind. 
     Therefore, in addition to the adapter  30  designed according to the invention, accessory parts  40  that are correspondingly matched to an adapter  30  designed in this manner also fall within the scope of the present disclosure. 
     Finally, in the case of “new” weapons, the part of the adapter  30  on the weapon side may be a part of the handguard  210 , such that the part of the adapter  30  having the lager radius, together with the bayonet attachment, is formed integrally on the front end of said weapons. Put simply, the adapter  30 , as a separate component, can be omitted, more exactly the rear portion  32  is omitted, and the front portion  34  of the adapter  30  is formed integrally on the handguard  210 . 
     As explained above, some aspects of the the present invention make it possible for the mechanical stability of the attachment of an accessory part, the precision of the weapon, as well as the heat dissipation at the barrel and/or a muzzle attachment to be improved, and nonetheless for a reduction of the thermal signature to be achieved. 
     In the description and the claims, the terms “front,” “rear,” “upper,” “lower,” etc., are used in the generally accepted manner and with reference to the subject matter in the conventional use position thereof. That is to say that, in a weapon, the muzzle of the barrel is at the “front,” the slide is moved to the “rear” by means of the explosion gases, etc. 
     It should also be noted that, in the description and the claims, specifications such as “lower region” of an object means the lower half, and in particular the lower quarter, of the overall height, and “lowest region” means the lowest quarter and in particular an even smaller part; while “central region” means the central third of the overall height (width−length). All these specifications are used in their generally accepted meaning, applied to the intended position of the object in question. 
     In the description and the claims, “substantially” means a deviation of up to 10% of the specified value, if physically possible both upwards and downwards, but otherwise only in the reasonable direction, and in the case of degree specifications (angle and temperature) this means±10°. 
     Unless otherwise specified, the term “combination” or “combinations” means all types of combinations, from two of the components in question to a plurality or all of components of this kind, and the term “containing” also means “consisting of.” 
     The features and variants specified in the individual embodiments and examples can be combined freely with those of the other examples and embodiments, i.e. without the other features of the relevant example, and can in particular be used for characterizing the invention in the claims, without necessarily incorporating the other features/details of the relevant embodiment or of the relevant example. 
     
       
         
           
               
             
               
                   
               
               
                 Listing of Reference Numerals 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 10 
                 barrel 
                 30 
                 adapter 
               
               
                 11 
                 muzzle 
                 310 
                 push button 
               
               
                 12 
                 housing (receiver) 
                 311 
                 spring 
               
               
                 13 
                 stock (butt stock) 
                 312 
                 groove/slot 
               
               
                 14 
                 grip 
                 313 
                 pressure surface (push surface) 
               
               
                 111 
                 muzzle attachment 
                 314 
                 locking surface (locking area) 
               
               
                 120 
                 cartridge chamber 
                 315 
                 clamping pin (locking pin) 
               
               
                 130 
                 gas block 
                 316 
                 clamping pin hole (locking 
               
               
                   
                   
                   
                 pin hole) 
               
               
                 140 
                 barrel axis 
                   
                   
               
               
                   
                   
                 32 
                 rear portion (rear section) 
               
               
                 20 
                 sheath, overall 
                 320 
                 recess for push button 
               
               
                   
                 (handguard assembly) 
                   
                 (button recess) 
               
               
                 210 
                 handguard 
                 323 
                 rear radial distance 
               
               
                 220 
                 heat shield 
                 330 
                 heat shield guide 
               
               
                 230 
                 heat shield guide 
                 331 
                 screw holes towards handguard 
               
               
                   
                 extension 
                   
                   
               
               
                 231 
                 guide 
                 332 
                 screws 
               
               
                 240 
                 ventilation holes 
                 333 
                 contact surface for handguard 
               
               
                   
                 (vent holes) 
                   
                   
               
               
                 40 
                 accessory 
                 34 
                 front portion (front section) 
               
               
                 410 
                 shroud (cover) 
                 341 
                 bayonet extension (bayonet lock) 
               
               
                 420 
                 filling 
                 342 
                 coupling surface 
               
               
                 421 
                 stop 
                 343 
                 front radial distance 
               
               
                 425 
                 locking hole 
                 344 
                 adapter opening 
               
               
                   
                 (button hole) 
                   
                   
               
               
                 441 
                 bayonet notch 
                   
                   
               
               
                 442 
                 counter-coupling 
                 50 
                 gap 
               
               
                   
                 surface 
                   
                   
               
               
                   
                   
                 51 
                 intermediate space (spacing) 
               
               
                   
                   
                 52 
                 connection space (connection 
               
               
                   
                   
                   
                 chamber)