Ball Rifled Barrel

Abstract

A firearm, including a barrel having a plurality of spherical bearings contacting a projectile discharged therethrough, is disclosed. Each of a plurality of sets of centrally apertured discs retains a plurality of rotatable spherical bearings. A part of each bearing within a set of discs extends into the centrally disposed aperture. The sets of discs are mounted adjacent one another within a sleeve to form a barrel for a firearm. The bore of the firearm is defined by the innermost extensions of the spherical bearings within a set of discs. A key way within each of the discs with a helically formed key extending adjacent the inner surface of the sleeve to angularly position each of the discs about its longitudinal axis. The spherical bearings of the positioned discs thereby define a number of helixes within the bore of the barrel, where the number of helixes corresponds to the number of spheres retained by a set of discs.

Description

The present patent application describes subject matter related to the subject matter of copending patent applications entitled "Low Friction Projectile", filed Oct. 2, 1972, and assigned Ser. No. 294,280 and "Rotary Shell Chamber", filed Dec. 18, 1972, and assigned Ser. No. 316,119 and invented by the same inventor.

The present invention relates to rifled barrels, and more particularly, to barrels having a plurality of bearings extending into the bore to guide the passage of a projectile therethrough.

Firearms which discharge a single projectile or bullet at a time usually incorporate a bullet guide feature within the barrel referred to as rifling. In conventional firearms, the rifling is obtained by means of two or more helical ridges or lands within the bore and extending for the full length of the bore.

There are several conventional methods for manufacturing a rifled barrel. In essence, these methods incorporate the following two steps. First, a hole is drilled throughout the length of the barrel. The diameter of the hole is of a lesser diameter than the diameter of the bullet. Second, two or more grooves are cut or milled in a helical path throughout the length of the hole. The depth of the grooves may vary depending upon the bore diameter and type of bullet to be fired therethrough. For the calibers usually used in military rifles or in hunting rifles, the depth of the grooves is approximately 0.0035 to 0.004 inches. The pitch of the grooves may vary between one revolution per 8 inches of bore to one revolution per 12 inches of bore.

The rifling in a barrel performs a primary function of imparting a spinning motion to the bullet about its longitudinal axis. The spinning bullet, in accordance with well-known gyroscopic principles, tends to be more stable in flight and less deflected by wind shear than a non-spinning bullet. Thus, a more accurate firearm is obtained if the firearm incorporates the rifling feature.

In order to insure that the spinning motion is in fact imparted to the bullet, there must be a friction fit between the bullet and the lands, which friction fit tends to form a plurality of channels about the periphery of the bullet corresponding to the lands. The bullet, as it travels through the bore, will spin because there is less friction between the bullet and the bore when the formed channels follow the helical path of the lands. Because of the friction fit, the periphery of the bullet disposed intermediate the formed channels will extend into the grooves adjacent the lands. The reduced space within the grooves tends to form a seal between the adjacent periphery of the bullet and the groove to more effectively prevent an escape of the expanding gases between the bullet and the groove.

Before the advent of fast burning gunpowder, the friction fit described above served a further useful purpose. The friction fit tended to restrain the passage of the bullet through the bore and thereby impeded the acceleration of the bullet. The slow initial velocity of the bullet provided a time lapse during which the slow burning powder could fully ignite. Thereby, a maximum gas pressure buildup would occur before the bullet exited from the bore.

With the presently available and widely used fast burning gunpowders or propellants, a portion of the force is exerted by the propellant and is used to form the channels within the outer, surface of the bullet. After the channels are formed, however, there is no need for the bullet to continue to be frictionally in contact with the barrel to establish a time lapse and permit the propellant to fully ignite before the bullet exits from the barrel.

It is therefore a primary object of the present invention to provide a low friction path for a projectile traveling through a barrel while forcing the projectile to spin about its longitudinal axis.

Another object of the present invention is to provide a low friction bore for various sized barrel lengths.

Yet another object of the present invention is to provide a plurality of rotatable bearings within the bore of a barrel.

Still another object of the present invention is to provide a plurality of discs positioned adjacent one another to form a rifle barrel.

A further object of the present invention is to provide a plurality of identical discs positioned adjacent one another and angularly keyed with one another to form rifling within a barrel of a firearm.

A yet further object of the present invention is to provide a plurality of apertured discs positioned adjacent one another, which discs include a plurality of rotatable spheres partially extending into the respective apertures.

A still further object of the present invention is to provide a bore construction adaptable to various sized calibers.

Another further object of the present invention is to provide a swaging die for directing a bullet into a low friction bore.

These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.

The present invention may be described with more specificity and clarity with reference to the following drawings, in which:

FIG. 1 illustrates the environment of the present invention.

FIG. 2 illustrates the barrel sleeve of the present invention.

FIG. 3 illustrates a cross-section of the barrel taken along lines 3--3 as shown in FIG. 1.

FIG. 4 illustrates a cross-section of a disc assembly taken along lines 4--4 as shown in FIG. 3.

FIG. 5 illustrates a top view of a disc taken along lines 5--5 as shown in FIG. 4.

FIG. 6 illustrates a cross-section of the swaging die taken along lines 6--6 as shown in FIG. 1.

FIG. 7 illustrates a cross-section of a modified form of the swaging die shown in FIG. 1.

Referring to FIG. 1, there is shown a rifle 1 which rifle includes a barrel 2, a receiver 5 and a stock 3. In proximity to the receiver 5 and the pistol grip of stock 3, there are disposed a trigger guard 7 protecting trigger 8, and a lever 9 for positioning the shells within receiver 5 and for arming trigger 8. A safety mechanism 6 prevents inadvertent discharge of the rifle. A sight 4 is disposed at the tip of barrel 2.

The structural features of barrel 2 are shown in the cutaway view. In essence, the structure of barrel 2 includes a plurality of apertured disc assemblies 15 stacked adjacent one another. A sleeve 21 encloses the stack of disc assemblies 15 and maintains the disc assemblies in alignment with one another. Each of the disc assemblies 15 includes a first disc 16 and a second disc 17. These two discs retain a plurality of spaced bearings, such as bearings 18 and 19, as shown. The bearings may be of any one of several possible shapes. However, by using spheres as bearings, many orientation and positioning problem areas can be circumvented. Thus, in the following discussion it will be assumed that the bearings are spherical.

The apertures of each of the disc assemblies 15, being aligned by the surrounding sleeve 21, define a cylindrical cavity 23 within barrel 2. Each of the spheres (such as spheres 18 and 19) of the disc assemblies 15 extends into cylindrical cavity 23. The inward extremities of the spheres define points on a circle, which circle has a diameter less than the caliber of the projectile or bullet to be discharged through the barrel.

It is a well-known practical impossibility for the shell loading mechanism of rifles to perfectly position the shell in alignment with the bore of the barrel without the use of some type of a receiving chamber. For this reason, pump or trombone action, lever action and bolt action rifles invariably position the shell within a receiving chamber. Where, however, the shell loading mechanism is a rotary chamber, some type of guiding apparatus must be used to guide the discharged bullet from the casing into the bore.

A barrel constructed in accordance with the present invention may be used in conjunction with any one of the above identified actions and with any type of shell loading mechanism. If the shell loading mechanism so permits, a receiving chamber is disposed within the receiver to align the bullet with the bore. If a shell loading mechanism, such as rotary chamber is used, a bullet guide apparatus or swaging die must be used. The swaging die to be described is readily adaptable for use in conjunction with any type of shell loading mechanism. The swaging die also serves the function of free bore, that is, the relieving of the pressure developed at the instant the gunpowder ignites.

Referring to FIG. 1, a swaging die 10 includes an inlet 13 and an outlet 12, where the inlet is of a larger diameter than the outlet. The spatial separation between the inlet 13 and outlet 12 and their common centers, define a hollow cone 14. A plurality of spirally shaped ridges lands 11 are disposed about the surface of cone 14. The diameter of outlet 12 is equivalent to the diameter of the cylindrical cavity 23 defined by disc assemblies 15. The height of lands 11, that is, the distance to which the lands extend inwardly from cone 14, is equivalent to the distance the spheres (such as sphere 18) extend into cylindrical cavity 23. The position of lands 11 at outlet 12 corresponds to the position of the spheres of the adjacent disc assembly. Similarly, the pitch defined by lands 11 is equivalent to the pitch of the helically arranged spheres. Thus, a path defined by one of the lands 11 is smoothly carried forward by the spheres positioned within the succeeding disc assemblies 15.

In operation, a shell ready to be discharged within receiver 5 is approximately aligned with the bore of barrel 2 such that on discharge of the shell, the bullet will pass through swaging die 10 and into the bore. If the bullet is not perfectly aligned with the bore, the bullet, on passing through inlet 13, will strike one or more of lands 11. Lands 11 will direct the bullet central to the swaging die 10 until the bullet is aligned with outlet 12 and the bore. Simultaneously, lands 11 will form depressions or channels about the periphery of the bullet. These channels, initially formed by lands 11, will engage the corresponding helical spheres as the bullet passes into and through barrel 2. The helically arranged spheres, in seriatim engaging the channels, will tend to cause the bullet to spin about its longitudinal axis. In this manner, the spheres perform the function of rifling in a barrel and impart a spinning motion to the bullet exiting from the barrel. Further, the spheres guiding the bullet through the barrel, being free to rotate on contact with the bullet, present a minimum frictional resistance to the bullet.

Further, the initial swaging action, forming the channels about the periphery of the bullet, tends to place the periphery of the bullet in closer proximity to cylindrical cavity 23. The close proximity between the periphery of the bullet and cylindrical cavity 23 minimizes the pressure losses due to escaping gas intermediate the bullet and the cylindrical cavity. It has been assumed that the channels formed within the periphery of the bullet are always in engagement with at least a sphere such that there is negligible if any flow of gas within any one of the channels.

Sleeve 21 is shown in further detail in FIG. 2. A helical key 22 is disposed about the inner surface of sleeve 21. The cross-sectional shape of key 22 is not critical but it has been found that a triangular cross-section is structurally simple and mechanically sufficient to orient the disc assemblies 15 within the sleeve.

The structural features of the disc assembly 15 will be explained in further detail with reference to FIGS. 3, 4, and 5. FIG. 3, showing a cross-section of barrel 2, illustrates the mechanical alignment between sleeve 21 and disc assembly 15. Key 22, secured to sleeve 21, cooperates with a V-shaped groove 24 disposed across the cylindrical edge of disc assembly 15. In this manner, disc assembly 15 is inhibited from rotation about the longitudinal axis of barrel 2. Disc assembly 15 includes three spheres 18, 19 and 20, extending into cylindrical cavity 23. These spheres are separated from one another by an angle of 120.degree.. It is to be understood, that four or more spheres may also be used. Each of the spheres shown, extends into cylindrical cavity 23 for a slight distance, such as a few thousandth of an inch. As discussed above, the circle defined by the innermost extensions of spheres 18, 19 and 20 is equivalent to the caliber of the rifle.

Referring now to FIG. 4, there is shown a cross-section of disc assembly 15 illustrating a first disc 16 and a second disc 17. Each of the discs 16 and 17 includes a recess 26 and 25, respectively, which recess houses and encloses a major part of sphere 19. Each of the recesses 25 and 26 includes a retaining lip 27 and 28, respectively, which lip secures sphere 19 within recesses 25 and 26 and prevents removal of the sphere unless discs 16 and 17 are separated. The enclosure defined by recess 25 and lip 27 and recess 26 and lip 28 is slightly larger than the enclosed portion of sphere 19 such that sphere 19 may rotate therein.

The interior cylindrical sides 29 and 30 of the discs define the cylindrical cavity 23. The external cylindrical sides 31 and 32 of the discs define the longitudinal periphery of the disc assembly 15. The diameter of the periphery of the disc assembly 15 is slightly less than the internal diameter of sleeve 21 such that the disc assembly fits snugly within sleeve 21.

In FIG. 5, there is shown the internal lateral side of second disc 17. It is to be understood that the internal lateral side of first disc 16 is the mirror image of the equivalent lateral side of the second disc. As best shown in this figure, each of the spheres 18, 19 and 20 are disposed within their individual recesses 36, 25 and 35, respectively. Each of these recesses are open to cylindrical side 29 whereby the respective spheres may protrude within the cylindrical cavity 23. The V-shaped groove 24 is disposed within the periphery 31 of second disc 17. Groove 24 receives key 22 to align the second disc within sleeve 21, as discussed above.

Each of the disc assemblies 15, as shown in FIG. 1, has an identical spatial relationship between its groove 24 and its spheres 18 and 19 (and 20). In example, if one were to axially align each of the disc assemblies 15 with their respective grooves forming a straight line, the respective spheres would be aligned as three straight lines. However, because of the helically disposed key 22, the disc assemblies 15 are slightly angularly misaligned with respect to each other. This slight misalignment will cause the respective spheres 18, 19 and 20 to define three helical paths within cylindrical cavity 23. These three helical paths define the rifling in the barrel of the present invention.

Referring now to FIG. 6, there is shown an end view of the swaging die 10 discussed above with respect to FIG. 1. From this figure, it can be clearly seen that cone 14 acts as a funnel to direct a discharged bullet into alignment with the center of the bore. The lands 11 are spiral and of a size equivalent to the protruding part of the respective spheres of each of the disc assemblies 15. The ends of lands 11, adjacent outlet 12, are aligned with the helical paths defined by the three sets of helically arranged spheres. In this manner, a bullet, being initially channeled by lands 11, will continue to travel through the barrel 2 with the channels receiving and riding on the respective rotatable spheres.

FIG. 7 illustrates a modification of the above discussed die. As shown, three disc assemblies, 40, 41 and 42 perform the same function as the swaging die shown in FIGS. 1 and 6. Each of the disc assemblies 40, 41 and 42 includes a first and second disc 43 and 44, 45 and 46, and 47 and 48, respectively. These discs are similar in construction to first and second discs 16 and 17, respectively, of disc assembly 15. The difference between disc assemblies 40, 41 and 42 and disc assemblies 15 is the amount by which spheres 53, 54, 55, spheres 56, 57, 58 and spheres 59,60 61, respectively, extend beyond inner surfaces 50, 51, and 52, respectively. In disc assembly 40, immediately adjacent the first of disc assemblies 15, the respective spheres 53,54,55 extend inwardly almost as much as the respective spheres of disc assembly 15. In disc assembly 41, the respective spheres 56,57,58 extend for a slightly less distance than the spheres of disc assembly 40. Similarly, the respective spheres 59,60,61 of disc assembly 42 extend for an even lesser distance than the spheres of disc assembly 41. In this manner, the inward extremities of the respective spheres of the adjacent disc assemblies define a truncated cone. This truncated cone, axially limited by inlet 62 and outlet 63, performs the same function as the of swaging die 10. Although not shown, disc assembly 40, 41 and 42 also include a V-shaped groove cooperating with key 22 such that the inner extremities of the longitudinally aligned spheres define spirals, which spirals are similar in function and purpose to lands 11 of swaging die 10. Thus, a swaging die constructed in accordance with the above description, and as shown in FIG. 7, orients a discharged bullet into alignment with the bore of barrel 2.

While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials, and components, used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principles.

Claims

I claim:

1. A firearm including a receiver and a barrel extending from the receiver, wherein said barrel comprises:

a. a cylindrical sleeve defining the outer diameter of the barrel;

b. a plurality of adjacent apertured disc assemblies fitted within said sleeve and axially aligned therewith;

c. keying means for angularly displacing adjacent ones of said disc assemblies; and

d. a plurality of rotatable bearings partially extending from within each of said disc assemblies into the aperture of said disc assemblies, whereby a projectile discharged by the firearm contacts said bearings when passing through said barrel.

2. The invention as set forth in claim 1 wherein said disc assemblies comprise a pair of mirror image discs, each said disc including a recess for receiving a part of each said bearings.

3. The invention as set forth in claim 2 wherein said bearings comprise spheres.

4. The invention as set forth in claim 3 wherein said recesses are open to said aperture to permit said sphere to extend into said aperture.

5. The invention as set forth in claim 1 wherein said keying means includes a helical key adjacent the inner surface of said sleeve and a key way disposed in each of said disc assemblies for receiving said key.

6. The invention as set forth in claim 5 wherein said key is triangular in cross-section and said key way is a V-shaped groove disposed longitudinally across the outer surface of each of said disc assemblies.

7. The invention as set forth in claim 1 including a swaging die disposed within the receiver of the firearm for guiding a projectile into said barrel.

8. The invention as set forth in claim 7 wherein said swaging die includes:

a. an outlet of a size equivalent to the size of said aperture of said disc assembly;

b. an inlet of a size larger than said outlet, whereby said outlet and inlet define the axial extremities of a truncated cone;

c. a plurality of spiral grooves disposed within said cone defining a plurality of spiral lands between adjacent grooves; and

d. said lands adjacent said outlet extending into said outlet for a distance equivalent to the extension of said bearings into said aperture of said disc assemblies.

9. The invention as set forth in claim 7 wherein said swaging die includes a further plurality of apertured disc assemblies, each one of said further disc assemblies having a plurality of bearings extending into said respective aperture for a predetermined distance, said predetermined distance being defined by the position of respective ones of said plurality of disc assemblies, wherein:

a. said bearings of said further disc assembly immediately adjacent the first one of said disc assemblies within said barrel extend into said respective aperture for a distance less than the distance of said bearings of said first one of said disc assemblies; and

b. said bearings of each said further disc assemblies more remote from said first one of said disc assemblies extending into said respective aperture for a distance less than the distance of said preceding further disc assembly, whereby said bearings of said further plurality of apertured disc assemblies extending into said respective apertures define a truncated cone.