OBJECT OF THE INVENTION
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The present invention relates to a quick-assembly breech plug for muzzleloader firearms, applicable in the arms industry, and more specifically in the field of firearms for use in sports, allowing a quick and effective assembly and disassembly of the breech plug in the rear end of the barrel, being an extremely practical breech plug which is simple to manufacture and has a low cost, which allows its coupling in the barrel from any angular position.
BACKGROUND OF THE INVENTION
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Firearms which are loaded through the muzzle of the firearm, usually known as muzzleloader firearms, incorporate at the rear end of the barrel, opposite the muzzle, a part referred to as breech plug which can be disassembled from the barrel, having the functions of closing the rear end of the barrel during its use, while at the same time it allows the ignition of the charge, likewise allowing accessing the inside of the barrel when it is disassembled for the purpose of performing operations for cleaning said barrel.
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The breech plug is currently fixed to the rear end of the barrel by means of a standard thread, said thread having a single start, the operations for assembling and disassembling the breech plug in the barrel therefore require considerable time since a considerable length of thread must be screwed or unscrewed, step by step, until achieving the complete extraction or introduction of the breech plug between 12 and 20 turns on average.
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For the purpose of solving the problem set forth in the previous paragraph, there are quick-assembly breech plugs incorporating means to allow quickly disassembling the breech plug from the rear end of the barrel. Said means consist of incorporating planar recessed grooves, like bevel edges, located in diametric opposition according to the longitudinal direction of the threaded male body of the breech plug, said planar recessed grooves being provided to be axially inserted in a certain and tight angular position inside the barrel, for which said grooves are located in correspondence with complementary bevel edges located internally in the barrel, allowing a quick introduction of the breech plug in the barrel. Then, by means of a 90° rotation of the breech plug, the latter is secured to the barrel by means of the threaded coupling of the male thread located in the male body of the breech plug, with a complementary toothing, like a female thread, located internally in the barrel.
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The main drawback of these breech plugs is that their manufacture is complicated and expensive, since the machining of said recessed grooves and bevel edges in the previously threaded male body of the breech plug is required, in addition to having to precisely incorporate recesses and complementary toothing inside the barrel, requiring the breech plug to be in a certain angular position before introducing it in the barrel, which delays the operations for assembling it, which furthermore require the use of suitable tools for screwing and unscrewing the breech plug.
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In this sense, patent application no. US-2006/0248771-A1 relates to a muzzleloader firearm comprise a breech plug for quickly assembling the breech plug in the barrel, being based on a bayonet-type system, which incorporates teeth and grooves both in the barrel and in the breech plug configured to allow a coupling and uncoupling by means of 90° rotations, having as a drawback, in addition to those indicated above, the fact that considering the described coupling means it is extremely difficult to prevent firing gases from escaping through said clearances.
DESCRIPTION OF THE INVENTION
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The present invention relates to a quick-assembly breech plug for muzzleloader firearms, which allows both assembling and disassembling the breech plug in the barrel in an extremely quick and effective manner, for the purpose of removing the breech plug to clean the loader or to remove a charge housed in the barrel. Said quickness and effectiveness are based on the breech plug of the invention requiring for its assembly and/or disassembly a smaller number of rotations in comparison with the currently existing breech plugs, the thread of which has a single start. The breech plug of the invention is simple, practical and inexpensive to manufacture, not requiring complex means for coupling to the barrel, as in the case of bayonet-type couplings, and allowing its introduction from any angular position, without having to be in a certain angular position for its introduction.
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The quick-assembly breech plug for muzzleloader firearms proposed by the invention comprises a cylindrical body configured to be internally tightly coupled in a rear end of a barrel. The breech plug likewise comprises a head configured to define a limit coupling position of the breech plug inside the barrel.
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According to the invention, the cylindrical body comprises, externally, a male thread having at least two starts located close to a front end of the breech plug, opposite the head. Said starts of the male thread are defined depending on the inclination of the thread fillet, being able to be clearly identified at any point of the cylindrical body upon making an imaginary section according to a plane perpendicular to an axis of revolution of said cylindrical body, being able to count in said plane the starts that the male thread has, preferably 4 threads, 3 revolutions=12 screw ridges. This furthermore causes a large angle in the screw threads allowing the quick detachment of the breech plug and barrel, being able to be loosened or placed by hand without needing tools, except for cases of jamming due to dirt.
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Said male thread is configured to screw into a female thread located internally in the rear end of the barrel, allowing the coupling between the breech plug and the barrel.
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It is contemplated that the front end of the cylindrical body comprises an end section without male thread, i.e., a smooth section, said smooth end section having at least one perimetric groove configured to house an O-ring seal configured to prevent firing gases from escaping through a clearance located between the cylindrical body and the barrel when the firearm is fired and the breech plug is coupled in the barrel.
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Likewise, the front located in correspondence with the front end of the breech plug has a planar face increasing the resistance of the breech plug, for the purpose of withstanding the large actions to which it is subjected during the ignition of the firearm.
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On the other hand, for the purpose of handling and operating the breech plug more comfortably and easily, the possibility of the head comprising a side surface in which at least one blind hole is located is contemplated, in which said blind hole is configured to house and receive a tooth of a tool or implement like a key, said blind hole receiving the transmission of a torque coming from said tool to cause the screwing and/or unscrewing of the breech plug in the barrel (4 orifices).
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Likewise, it is contemplated that the side surface of the head is knurled in order to allow manually gripping the breech plug for its operation, preventing its slipping.
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Finally, it is contemplated that the breech plug comprises an axially centered inner hole configured with a housing for the primer cap and arranged to transmit the ignition to the powder.
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Therefore, according to the described invention, the quick-assembly breech plug for muzzleloader firearms proposed by the invention is an advance in the breech plugs used up until now, and fully and satisfactorily solves the problems previously set forth in the sense of allowing a quick and effective assembly and/or disassembly in the rear end of the barrel, being an extremely practical breech plug which is simple to manufacture and has a low cost, which allows its coupling in the barrel from any angular position.
DESCRIPTION OF THE DRAWINGS
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To complement the description which is being made and for the purpose of aiding to better understand the features of the invention according to a preferred practical embodiment thereof, a set of drawings is attached as an integral part of said description, in which the following has been depicted with an illustrative and non-limiting character:
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FIG. 1 shows a perspective view, from the side of the head, of the quick-assembly breech plug for muzzleloader firearms proposed by the invention.
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FIG. 2 shows a longitudinal section of the breech plug of the invention, having coupled thereto the O-ring seal in the perimetric groove located in the area corresponding to the front end of the breech plug.
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FIG. 3 shows a longitudinal section of the breech plug located in an uncoupled position in correspondence with the rear end of the barrel of a muzzleloader firearm.
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FIG. 4 shows an elevational view of a tool configured to operate the breech plug of the invention more comfortably and quickly.
PREFERRED EMBODIMENT OF THE INVENTION
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In view of the indicated figures, it can be observed how in one of the possible embodiments of the invention the quick-assembly breech plug for muzzleloader firearms proposed by the invention is a part of revolution comprising a cylindrical body (1) configured to be tightly coupled internally in the rear end (10′) of a barrel (10).
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The breech plug comprises a head (6) configured to define a limit coupling position of the breech plug inside the barrel (10), as can be interpreted in view of FIG. 3.
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The cylindrical body (1) externally comprises a male thread (2) having four starts located close to the front end (3) of the breech plug, opposite the head (6), according to a plane perpendicular to an axis of revolution of the cylindrical body (1).
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Said male thread (2) is configured to screw into a female thread (10″) located internally in the rear end (10′) of the barrel (10), as can be seen in FIG. 3.
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As can be seen in FIGS. 1 and 2, the front end (3) of the cylindrical body (1) comprises a smooth end section without male thread (2) having a perimetric groove (4) configured to house an O-ring seal (5).
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Said O-ring seal (5) is configured to prevent firing gases from escaping through a clearance located between the cylindrical body (1) and the barrel (10) when the firearm is fired and the breech plug is coupled in the barrel (10).
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According to a preferred embodiment of the invention, the O-ring seal (5) is made of an elastomer material configured to withstand high pressures and temperatures. For the purpose of maximizing the useful life of the O-ring seal (5), it is covered with molybdenum bisulfate grease, the possibility of covering it with any other suitable grease for its protection being contemplated.
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As can be seen in FIG. 2, the front located in correspondence with the front end (3) of the breech plug has a planar face for the purpose of increasing the resistance of the breech plug to withstand the large actions to which it is subjected during the ignition of the firearm.
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Likewise, the head (6) comprises a knurled side surface (7) in which there are located four blind holes (8) configured to receive a tooth (11′) comprised by a tool (11), depicted in FIG. 4, thus receiving the transmission of a torque caused by the screwing and/or unscrewing of the breech plug in the barrel (10), such tool being used in cases of jamming of the threads.
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Finally, as observed in FIG. 2, the breech plug comprises an axially centered inner hole (9) configured to transmit the ignition of the primer cap and the breech plug is coupled in the barrel (10).
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In view of this description and set of drawings, the person skilled in the art will understand that the embodiments of the invention which have been described can be combined in many ways within the object of the invention. The invention has been described according to some preferred embodiments thereof, but for the person skilled in the art it will be evident that many variations can be introduced in said preferred embodiments without exceeding the object of the claimed invention.
