Patent Application
20070175078
1. Field of the Invention
This invention relates generally to a process for metal working to produce double barrel shotgun barrels, and, more particularly it relates to a process for manufacturing over/under and side-by-side shotgun barrels from a single piece metal stock, and also to the resulting monolithic shotgun barrels so produced.
2. Description of the Prior Art
Double barrel shotguns are long known in the art. There are two basic types of double barrel shotguns being manufactured today. A first type of double barrel shotgun is commonly referred to as a “Chopper Lump” (English terminology) or a “Demibloc (Italian terminology)” barrel, and will herein be referred to as “Demibloc”. Demibloc barrels are formed from two metal tubes or single barrels, preferably of steel, that are of a length sufficient to form a shotgun. As a first significant step, the two metal tubes soldered together to form a roughly joined double barrel. The resulting double barrel is then filed, machined and otherwise worked in multiple steps using the skills and labor of multiple trades and crafts people. For example, as a first step a “Joiner” joins the two individual metal tubes and then solders them together along substantially their entire lengths. An “Actioner” fits and files the rough barrel to fit and match a separate action or firing mechanism to which the double barrel is to be attached. A “Striker” files the surfaces of the joined rough double barrel pieces to a desired finish. A “Straightener” straightens or regulates the joined barrels and also adjusts or bends the individual barrels by eye into a relative position to allow each barrel to shoot a projectile straight and also into a desired converging shot pattern at a given distance. A “Rib installer” solders the top sighting rib onto the combined double barrel tube, and also solders side ribs on either side of the tubes between the two barrels to secure them in the desired relative position.
Finally, a “Bluer” treats the combined double barrel to produce the desired oxidized blue-black coating onto the double barrel.
The second type of double barrel shotgun is commonly referred to as a “Monobloc” (Italian term). A Monobloc double barrel shotgun consists of an action block of metal, preferably steel, fitted to the action or firing mechanism of the shotgun. The Monobloc is preformed to carry at least two receiving holes designed to accept a pair of separate barrel tubes. Each separate tube is then set into and soldered to a receiving hole of the action block so that each protrudes from the action block, and is of a length sufficient to be formed into a shotgun. The two tubes are then held in position with wire or by a fixture and are then roughly tacked together along their entire lengths with solder. Then, the joined barrels are straightened or “Regulated” by hand into a relative position to allow each barrel to shoot a projectile straight and also into a desired converging or overlapping shot pattern at a prescribed distance. Next, the barrels are sent to a “Rib installer” to solder the top sighting rib and side ribs between the barrels that hold the tubes in place. The rough barrels are then sent to a “Striker” or “Finisher” to finish the surfaces of the barrels by filing and sanding. Finally, the barrels are sent to “Bluer” for bluing and final finish.
In addition, double barrel shotgun barrels are formed by the Demibloc and by the Monobloc process in over/under (O/U) and side by side (S/S) shotgun barrels It can therefore be seen, that the process of making a double barrel, whether by the Demibloc or the Monobloc process consists of a large number steps performed by many crafts an trades people, and, as a practical matter requires a great deal of time, say up to two and one half years to complete.
Accordingly, there exists a need for a process for manufacturing double barrel shotgun barrel systems which allows what have heretofore been many dissimilar trades to perform manufacturing and machining and finishing steps quickly, efficiently and in harmony in order to arrive at a finished double barrel shotgun barrel within a required specification. Additionally, a need exists for a process for manufacturing shotgun barrels which is quick and inexpensive and easy to replicate with precision. Furthermore, there exists a need for a process for manufacturing double barrel over/under and/or side by side shotgun barrels which allow a broad range of different types of barrels to be produced using substantially the same single piece of metal stock and material blank. There is a further need to precisely produce such double barrel over/under and/or side by side shotgun barrels quickly and without the use of the labor of multiple trades or craftsmen.
The present invention teaches methods for manufacturing double barrel shotgun barrels. In one embodiment the method comprises providing an elongated metal stock material of a given length and of sufficient height and width to be formed into a double barrel shotgun, the metal stock material having a first end and a second end. So long as the metal stock material meets those size requirements, it may be round, or square, or rectilinear or irregular in cross section, the desired starting cross section being easily milled or otherwise formed on the metal stock material. For purposes of simplicity it will be assumed that the metal stock material is round, or cylindrical or rectilinear in cross-section. As a first significant step in creating the double barrel of the present invention, two separate and spaced apart index markers are formed at both the first end of the metal stock material and at the second end of the metal stock material. The second index marker formed in the second end of the metal stock material is opposed to and aligned precisely linearly with the first index marker formed in the first end of the metal stock material longitudinally through the length of the metal stock material. The second index marker formed in the second end of the metal stock material is also opposed to and aligned linearly with the first index marker formed in the first end of the metal stock material longitudinally through the length of the metal stock material. Each pair of opposed first and second index markers serve to define what will be the centers of to-be-bored holes. In addition, and as is explained below, the index markers allow the metal stock material to be moved from one machine to another during various steps of the process of the present invention.
A first substantially straight guide element is then formed linearly along one surface of the external longitudinal length of the metal stock material. The first guide marker runs in a substantially straight line between the first end of the metal stock material and the second end of the metal stock material. A second guide marker is then formed linearly along the external longitudinal length of the metal stock material, and runs in a substantially straight line between the first end of the metal stock material and the second end of the metal stock material. However, the second external guide marker is spaced apart from and on a surface opposed to the first guide marker, and as explained and greater detailed below, is angled relative to the first external guide marker at what will be the angle of convergence of the to-be-formed bore holes. Then, using the first and second pairs of index markers, the first and second holes to be bored are established A first bore hole is formed linearly through the length of the metal stock material, the first bore hole being aligned with and guided by the first guide marker. Then, the second pair of index markers are used to establish the location of the second bore hole to be formed linearly through the length of the metal stock material, the second bore hole being aligned with and guided by the angle of the second guide marker, and therefore at the predetermined angle of convergence at a given distance from the end of the barrels. In practice, the angle of convergence between the first projectile hole and the second projectile hole is usually in the range of about 0.35° and about 0.40°. All of these steps are achieved with a minimum of handling; require no skilled trades or craftsmen. Then, the double barrel thus formed may be profiled and finished with a minimum of handling and without requiring skilled trades or crafts people.
As used with the present invention, the “index markers” may be holes or raised points, or any other form of index marker. Similarly, the “guide element” may be grooves, rails, or any other form of guide element.
Referring first to
The process for manufacturing over/under (O/U) 12 or side by side (S/S) 12A shotgun barrels of the present invention begins with obtaining a single piece of metal stock material 32, as shown in
The process of the present invention for manufacturing double barrel O/U or S/S shotgun barrels 12 or 12A according to the present invention is comprised of several steps, as well as optional steps. The first step, after obtaining an appropriate metal stock material 32, is determining the ultimate angle of convergence of the first and second two to-be-bored projectile holes 42 and 44, respectively (see
Now, in order to produce and replicate O/U or S/S double barrel barrels accurately and consistently, two precisely located and spaced apart index markers 46 and 48 are formed at the first end 34 of the solid metal stock material 32, and two precisely located and spaced apart matching index markers 46 and 48 are also formed at the second end 36 of the solid metal stock material 32. In preferred embodiments each pair of two index markers are a pair of spaced apart holes 46 and 48, formed, for example, by drilling into the first end 36 and a second end 46 and 48 of solid substantially cylindrical metal stock material 32. The first pair of index holes 46 and 48 formed in the first end 34 of the metal stock material 32 are preferably aligned linearly with the second pair of index holes 46 and 48 formed in the second end 36 of the metal stock material 32. Each pair of index holes 46 and 48 are aligned longitudinally through the length of the metal stock material 32 with the opposed pair of index holes 46 and 48. In the preferred practice of the present invention, the two index markers 46 and 48 at the first end 34 and the two index markers 46 and 48 at the second end 36 of solid stock material 32 are located between about 2.0 inches apart and about 2.5 inches apart. While the index markers 46 and 48 are herein noted to be holes, and specifically to be drilled holes, the index markers may be formed in any other manner, for example as projections, and by any other method.
Next, based on the locations of index markers 46 and 48, the exterior of metal stock material 32 is then profiled, using equipment and methods as detailed below, including the formation of accurately positioned converging external guides 52 and 54. Converging external guides 52 and 54 are located relative to one another at what will be the angle of convergence of the first and second to-be-bored projectile holes 42 and 44. As shown in
Then, as illustrated in
Then, after the location and setup of index markers 46 and 48 at ends 34 and 36 of solid metal stock material 32 is used to produce external guide groove elements 52 and 54 for either O/U 12 or S/S 12A shotgun barrels, external guide groove elements 52 having precise locations and angles of convergence are used to locate two to-be-bored projectile bore holes 42 and 44 that provide the desired overlap pattern that at a given distance. This is accomplished using the first pair of external guide groove elements 52 for alignment, a first bore hole 42 is formed linearly through the longitudinal length of the metal stock material 32, first bore hole 42 is formed using any suitable boring system. Then, metal stock material 32 is moved and placed into a second alignment with the boring system using second alignment guide groove elements 54, and second bore hole 44 is then formed linearly through the longitudinal length of the metal stock material 32 also using any suitable boring system, but at the predetermine angle of convergence with first bore hole 42, as shown in
The method of actually forming bore holes 42 and 44 in stock material 32 is not critical to the practice of the present invention. However, what ever type of bore hole forming system is used, converging external guides 52 and 54 will preferably be used to select and guide the angle of convergence between bore holes 42 and 44. For example, since the early eighteenth century a fixed, non-moveable single axis hand turned boring or drilling machine has been used to produce bore holes, and may be used to produce bore holes 42 and 44 in the practice of the present invention. This can be accomplished by cutting two longitudinal grooves like 52 and 54 in the surface of stock material 32, which grooves represent the desired convergent directions of bore holes 42 and 44. However, in the preferred process of the present invention, state-of-the-art automated power boring machines such as Computer Numerical Controlled (CNC) machines are used with converging external guides 52 and 54 to select and guide the angle of convergence between bore holes 42 and 44. As an important step in the process of the present invention, in order to accurately replicate bore holes from stock material 32 to stock material 32, one must mechanically establish the location of those bore hole centers. In the preferred practice of the present invention, those bore hole centers are locatable from index marker elements 46 and 48 which allow each piece of stock material 32 to be moved and repositioned on any boring machine, as the marker elements 46 and 48 serve as reference indexes that identify the correct location of the to-be-bored projectile holes 42 and 44 within the stock material 32, regardless of what type of boring machine was originally used. Once such converging external guides 52 and 54 are alternately placed on a machining table having a compatible locating element for aligning the boring element, and fixed into position, the boring machine hole line will be represented by the line of the guides 52 and 54. Therefore, in practice, when a first hole, say 42 is completed using external guides 52, the stock material 32 can then be placed in the second external guides 54, and the boring machine aligned to external guides 54, and bore hole 44 established with the desired angle of convergence. In each instance, the alignment of stock material 32 is established on the table and in the fixture by reference to index markers 46 and 48.
In the alternative, where the boring machine has very accurate moveable tables for positioning stock material 32, and where the centers of projectile holes 42 and 44 are locatable from index marker elements 46 and 48, the stock material 32 can be moved and positioned with respect to the boring tools so that and projectile bore holes 42 and 44 can be produced without reference to or use of converging external guides 52 and 54. Subsequently, the surface of stock material 32, as shown in
Finally, as shown in
It is apparent, that by adjusting the orientation of the system by 90° in several of the steps discussed above, that a S/S double barrel shotgun barrel 12A can be produced. It should be noted that side and top ribs 22 and 24 are produced with and integral to the finished double barrel products.
In any event, it is clear that in the practice of the method of the present invention, the monolithic O/U or S/S double barrels are not made from a composite of two tubes or single barrels that are joined together, for example by soldering, to make a joined, but not monolithic double barrel. Nor is it necessary for single barrels to be joined together and then bent relative to one another during their joining by eye reckoning into position to a desired angle of convergence, as in the prior art Demibloc and Monobloc processes. Rather, since the starting stock material 32 for production of O/U or S/S double barrels is solid elongated metal stock material in which the two bore holes 42 and 44 are accurately formed having the desired angle of convergence within the solid metal stock material 32, and remains as a continuously joined monolith that is neither amenable to or capable of having its bore holes 42 and 44 bent relative to one another to adjust their angle of convergence. In addition, the bore holes 42 and 44 formed within the solid metal stock material 32 produced using the method of the present invention react differently to the harmonics waves of flexation that are generated during firing of a projectile through bore holes 42 and 44, as compared to the flexation produced by the counterpart state-of-the-art joined double barrel produced by conventional Demibloc and Monobloc methods of manufacture, and therefore the angles of convergence that have been determined for use with the prior art joined systems are not applicable to the angles of convergence required for the double barrel shotgun barrels produced by the method of the present invention. It is therefore understood that the determination of the angle of convergence of the two bore holes 42 and 44 produced by the method of the present invention is a key element to producing even and overlaying shot patterns at any given distance. Because of the above noted differences in the harmonics waves of flexation that are generated during firing of projectiles from shotgun barrels produced by the method of the present invention, the selection of the angle of convergence for an O/U or S/S barrel formed from solid metal stock material is also different from those known and used for double barrels produced by prior art Chopper Lump and Demibloc.
By using the indexing holes and other steps and techniques described herein, the shotgun barrels produced by the method of the present invention can be reproduced with precision for each to-be-produced shotgun barrel, thus making the shotgun barrels interchangeable from shotgun to shotgun. For the most part, double barrel shotgun barrels produced by prior art methods have required semi-precise machining for each individual shotgun system and further finished by hand, and are not interchangeable from shotgun to shotgun. Similarly, the center to center bored holes 42 and 44 can be produced in sizes that are compatible with a large number of double barrel shotgun barrels in use today of a like gauge. It will be appreciated that the double barrel gun barrels can be finished to assume different forms in accordance to the needs of a manufacturer or gunmaker. A particular profile of a gunmaker's barrel can be produced in either the O/U or S/S type barrels of the present invention.
Thus, the process of the present invention which produces a solid monolithic barrel with little or no hands on skilled labor replaces the Demibloc barrel manufacturing procedures that require multiple trades and a great deal of time to complete. By comparison, the process of making a solid block barrel according to the method of the present invention to produce a single complete one piece solid unit is simple and fast. For example, in the current practice, a Demibloc barrel which is made using a number of Tradesmen takes approximately two and one half years to complete. By comparison, the double barrel of the present invention can be reproducibly manufactured and completely finished in about eight to about 24 hours, depending on the sophistication of the machines used. However, in producing the completed form shown at
In addition, side by side barrels, single barrels, pistol barrels, rifle barrels, and double rifle barrels can also be produced using the process of the present application.
The foregoing exemplary descriptions and the illustrative preferred embodiments of the present invention have been explained in the drawings and described in detail, with varying modifications and alternative embodiments being taught. While the invention has been so shown, described and illustrated, it should be understood by those skilled in the art that equivalent changes in form and detail may be made therein without departing from the true spirit and scope of the invention, and that the scope of the present invention is to be limited only to the claims except as precluded by the prior art. Moreover, the invention as disclosed herein may be suitably practiced in the absence of the specific elements which are disclosed herein.
