Single point rifling tool

A single-point rifling tool including a rifling head with a lateral opening, a hook ramp stationarily secured at a first end of the lateral opening, and a cutting tool movably secured at a second end of the lateral opening. The cutting tool is movable along an angled surface of the hook ramp between a retracted position and a cutting position so as to perform a rifling operation in only a single direction through a gun barrel so as to perform a rifling operation in only a single direction through a gun barrel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a single point rifling tool and, more specifically, to a single point rifling tool with a hook tool that is retractable and adjustable by moving along a stationary wedge.

2. Discussion of the Related Art

Barrel rifling is directed to machining one or more helical grooves into an internal surface of a gun barrel for the purpose of exerting torque on a projectile to cause it to spin during shooting. As a result, the projectile is stabilized and accuracy is improved. Rifling methods include single point cut rifling, button rifling, and broach rifling. Single point cut rifling has many advantages over the other types of rifling. For example, single point cut rifling tooling allows for the shape, number and depth of the helical grooves to be adjusted as necessary. In addition, single point cut rifling allows for closer tolerances to be held during rifling of the barrel. Single point cut rifling also exerts minimal stress on the barrel during the rifling process.

Traditionally, barrel rifling cutting tools for single point cut rifling include a hook tool that is attached to the end of a rod. The rod is rotated and pulled through a barrel. The hook tool removes a small amount of material with each pass. After cutting the shallow grooves, the hook tool is adjusted to subsequently cut deeper grooves. This process is repeated until the grooves reach the desired depth. Single point cut rifling is the most accurate method of rifling and produces low stress on the barrel during the cutting process. However, single point cut rifling takes a lot of time and is, therefore, quite costly.

Most single point rifling tools known on the market today adjust the hook tool to adjust the depth of the groove by adjusting the location of a wedge within the rifling tool after each push stroke. For instance, a bottom surface of the hook tool is placed against an angled surface of the wedge. At the end of each push stroke, the wedge is moved toward the hook tool in order to adjust the cutting depth of the hook tool. In turn, the hook tool is passed through the barrel at the same cutting depth for a pull stroke and a push stroke. At the end of the push stroke, the hook tool is adjusted and then sent through the barrel at the new depth for the pull stroke and subsequent push stroke. As a result, the hook tool is passed through the barrel at the same cutting depth in two directions. This can cause burring in the grooves as the hook tool makes contact with the grooves on the return push stroke. Further yet, the hook tool receives additional wear as it makes contact with the grooves on the return push stroke.

Therefore, there is a need in the art for a single point rifling tool that adjusts the cutting depth of a hook tool for each pull stroke through the barrel in a single direction, while also returning the hook tool to a retracted non-cutting depth for each push stroke through the barrel to avoid contact with the interior of the barrel.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a single-point rifling tool includes a rifling head with a lateral opening, a hook ramp stationarily secured at a first end of the lateral opening, and a cutting tool movably secured at a second end of the lateral opening. The cutting tool is movable along an angled surface of the hook ramp between a retracted position and a cutting position.

In accordance with another aspect of the invention, the single-point rifling tool also includes a channel formed in a first end of the rifling head and extending into the lateral opening. The channel is configured to receive a fastener. The fastener stationarily secures the hook ramp.

In accordance with yet another aspect of the invention, the single-point rifling tool includes a pull tube having a first end and a second end. The first end of the pull tube is coupled to a second end of the rifling head, while the second end of the pull tube is coupled to a bushing. In addition, an adjustment rod may be disposed within the pull tube so as to freely rotate within the pull tube. The pull tube may also extend through the bushing so as to freely rotate within the bushing. In such an embodiment of the invention, a threaded portion of the cutting tool extends into a channel formed in a first end of the adjustment rod. The threaded portion of the cutting tool is threadably engaged with the channel of the adjustment rod so that rotation of the adjustment rod causes movement of the cutting tool between the retracting position and the cutting position. Meanwhile, a second end of the adjustment rod is coupled to a rotation device that causes rotation of the adjustment rod. The second end of the rifling head may include an indentation formed therein and configured to receive the first end of the pull tube.

According to another aspect of the invention, a method of manufacturing a single-point rifling tool includes statically disposing a wedge within an opening of a rifling head of the tool and kinetically disposing a cutting tool within the opening of the rifling head of the tool adjacent an angled surface of the wedge. The cutting tool is movable along the angled surface of the wedge between a cutting position and a non-cutting position.

In accordance with another aspect of the invention, the method may also include forming a channel in a first end of the rifling head to the lateral opening and disposing a fastener within the channel configured to statically secure the hook ramp within the opening of the rifling head.

In accordance with yet another aspect of the invention, the method may also include coupling a first end of the pull tube to a second end of the rifling head and coupling a second end of the pull tube to a bushing. Further yet, an adjustment rod may be disposed within the pull tube. A threaded portion of the cutting tool extends into and is threadably engaged with a channel formed in a first end of the adjustment rod. In turn, rotation of the adjustment rod causes movement of the cutting tool between the retracting position and the cutting position. The method may also include coupling a second end of the adjustment rod to a rotation device configured to cause rotation of the adjustment rod.

In accordance with another aspect of the invention, the adjustment rod is configured to freely rotate within the pull tube. The adjustment rod may also extend through and be configured to freely rotate within the bushing. The method may also include coupling the first end of the pull tube with an indentation formed in the second end of the rifling head. In turn, the first end of the pull tube overlaps the indentation.

According to yet another aspect of the invention, a method of using a rifling tool to manufacture a rifled gun barrel includes providing the rifling tool, which includes a rifling head with an opening therein, a wedge statically secured within the opening at a first end thereof, a cutting tool movably secured within the opening at a second end thereof, a pull tube having a first end coupled to the rifling head and a second end coupled to a bushing, and an adjustment rod disposed within the pull tube. The cutting tool is threadably engaged with a first end of the adjustment rod so that rotation of the adjustment rod causes movement of the cutting tool along an angled surface of the wedge between a non-cutting position and a cutting position. The method further includes coupling a second end of the adjustment rod to a rotation device configured to cause rotation of the adjustment rod and moving the rifling tool linearly through a gun barrel to form the rifled gun barrel. The cutting tool is disposed in the cutting position for movement of the rifling tool through the gun barrel in a first direction, while the cutting tool is disposed in the non-cutting position for movement of the rifling tool through the gun barrel in a second direction.

In accordance with another aspect of the invention, the method also includes disposing the gun barrel in a chuck arrangement. The chuck arrangement is configured to rotate the gun barrel during movement of the rifling tool through the gun barrel.

In accordance with yet another aspect of the invention, the rifling tool is coupled to a tool track configured to cause movement of the rifling tool in the first and second directions. In addition, movement of the rifling tool through the gun barrel in the second direction is performed at a higher speed than movement of the rifling tool through the gun barrel in the first direction.

In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments described in detail in the following description.

First referring toFIGS. 1-6, perspective, top, side, and cross-sectional views of a single point rifling tool10are shown. For instance,FIGS. 3-4illustrate the rifling tool10in a retracted, non-cutting position12, whileFIGS. 5-6illustrate the rifling tool10in a cutting position14. As shown in the perspective and top views ofFIGS. 1-2, the rifling tool10has a first end16and a second end18. A rifling head20is disposed at the first end16of the rifling tool10, while a pull tube22and a bushing24are disposed at the second end18of the rifling tool10.

The cross-sectional views ofFIGS. 4 and 6depict the additional elements of the rifling tool10that are disposed within the rifling head20and the pull tube22. For example, the rifling tool10includes a hook ramp or wedge26and a cutting tool28, such as a hook tool, disposed within the rifling head20. In the representative embodiment of the invention, the hook ramp26and the hook tool28are disposed within a lateral opening30in the rifling head20, which is disposed between a first end32and a second end34of the rifling head20. The hook ramp26is disposed within the lateral opening30at a first end36of the lateral opening30, while the hook tool28is disposed within the lateral opening30at a second end38of the lateral opening30.

A channel40is formed in the first end32of the rifling head20and extends to the lateral opening30. An indentation42may also be formed in a first end44of the hook ramp26. In the representative embodiment of the invention, the channel40and the indentation42are sized to have a similar or the same diameter. A fastener46may be disposed within the channel40and into the indentation42in order to stationarily and statically secure the hook ramp26within the lateral opening30. For example, the fastener46may be a screw threadably engaged with the indentation42of the hook ramp26and/or channel40of the rifling head20. As shown inFIGS. 4 and 6, the channel40may include a countersink portion40adisposed at the first end32of the rifling head20, so that the screw46may be flush or spaced inward from the first end32of the rifling head20.

Similarly, another channel48is formed in the second end34of the rifling head20and extends to the lateral opening30. The channel48is sized so that the hook tool28may extend from the lateral opening30and through the channel48. As shown inFIGS. 4 and 6, the hook tool28includes a cutting portion28adisposed adjacent the hook ramp26, a main portion28bextending through the channel48, and a threaded portion28cextending out the channel48and into an adjustment rod50disposed within the pull tube22.

The adjustment rod50includes a channel52formed in a first end54of the adjustment rod50. The channel52is configured to receive the threaded portion28cof the hook tool28. In the representative embodiment of the invention, the channel52is also threaded so as to be threadably engaged with the threaded portion28cof the hook tool28. The adjustment rod50is able to freely rotate within the pull tube22. Further, as the adjustment rod50rotates, the threaded engagement of the channel52of the adjustment rod and the threaded portion28cof the hook tool28causes the hook tool28to move longitudinally within the rifling head20. For example, a clockwise rotation of the adjustment rod50causes the hook tool28to move toward the first end32of the rifling head20, while counterclockwise rotation of the adjustment rod50causes the hook tool28to move away from the first end32of the rifling head20, or vice versa.

In the representative embodiment of the invention, a bottom surface28dof the cutting portion28aof the hook tool28is in contact with and rests upon an angled surface26aof the hook ramp26. As a result, when the hook tool28moves longitudinally toward the first end32of the rifling head20, the bottom surface28dof the cutting portion28aof the hook tool28moves along and ascends the angled portion26aof the hook ramp26so that the cutting portion28aof the hook tool28is raised to increase the cutting depth of the rifling tool10. Conversely, when the hook tool28moves longitudinally away from the first end32of the rifling head20, the bottom surface28dof the cutting portion28aof the hook tool28moves along and descends the angled portion26aof the hook ramp26so that the cutting portion28aof the hook tool28is lowered to decrease the cutting depth of the rifling tool10.

As shown inFIG. 11, a second end56of the adjustment rod50is coupled to a rotation device58, such as a servo motor. In turn, the servo motor58controls the rotation of the adjustment rod50. As a result, a controller may be electrically coupled with the servo motor58to control the rotation of the adjustment rod50and the depth adjustment of the hook tool28during the rifling of a barrel.

FIGS. 1-6further illustrate the bushing24disposed at a second end64of the pull tube22, while a first end66of the pull tube22is coupled to the second end34of the rifling head20. Meanwhile, the adjustment rod50extends through the bushing24and is able to freely rotate within the bushing24. In the representative embodiment of the invention, the first end66of the pull tube22is permanently coupled to the second end34of the rifling head20by way of micro-welding. Meanwhile, the second end64of the pull tube22is also permanently coupled to the bushing24by way of micro-welding. In other embodiments of the invention, the pull tube22may be joined together with the rifling head20and the bushing24using alternative methods.

Referring toFIGS. 4 and 6-8, the second end34of the rifling head20is shown to include an indentation68. The indentation68is configured to receive the first end66of the pull tube22. That is, the outer diameter of the indentation68is equal to or less than the inner diameter of the pull tube22. In turn, the pull tube22and rifling head20are permanently coupled together as described above along the overlap62of the second end34of the rifling head20and the first end66of the pull tube22. Consequently, the rifling head20and the pull tube22are coupled together along the overlap62of the first end66of the pull tube22and the indentation68at the second end34of the rifling head20.

FIGS. 9 and 10further depict the hook ramp26of the rifling tool10. As previously discussed, the hook ramp26includes a channel42formed in the first end44of the hook ramp26and the angled surface26aformed at a second end60of the hook ramp26. The channel is configured to receive the fastener46in order to secure the hook ramp26within the rifling head20. More specifically, the hook ramp26is secured in a stationary position at the first end36of the lateral opening30of the rifling head20. As a result, the hook tool28is able to move up and down the angled surface26aof the hook ramp26as the hook tool28is moved within the lateral opening30of the rifling head20by way of the adjustment rod50and servo motor58.

Next,FIG. 11illustrates a rifling machine70including the previously discussed rifling tool10. At a first end72of the machine70, a barrel74is disposed within a rotating chuck arrangement76. Once secured within the chuck arrangement76, the barrel74is able to be rotated at variable speed while the rifling tool10is moved through the barrel74. The benefits of this will be described in further detail below. Further, the second end18of the rifling tool10is disposed within the servo motor58, which is supported on a tool track78.

In the neutral position shown inFIG. 11, the servo motor58and second end18of the rifling tool10are disposed adjacent a second end82of the machine70. The tool track78extends from adjacent the second end82of the machine70to a location displaced from the first end72of the machine and the chuck arrangement76. During the push stroke, the servo motor58and rifling tool10are moved along the tool track78from the neutral position toward the barrel74and chuck arrangement76. As the rifling tool10passes through the barrel74on the push stroke, the hook tool28is moved from through the barrel74from a first end84of the barrel74and past a second end86of the barrel74. During the push stroke, the hook tool28is in the retracted position12so as not to make contact with the barrel74.

Once the rifling tool10has moved to a position where the hook tool28has passed completely through the barrel74, the rifling tool10stops moving, and the servo motor58is activated to move the hook tool28to the cutting position14. The rifling tool10is then pulled back through the barrel74along the tool track78while the chuck arrangement76rotates the barrel74for rifling the interior surface of the barrel74. As such, the hook tool28is in the cutting position28during the pull stroke, when the hook tool28is moved from the second end86of the barrel74to the first end84of the barrel74.

Once the rifling tool10has moved to a position where the rifling tool10and its hook tool28have been removed from the first end84of the barrel74, the servo motor58is activated to move the hook tool28back to the retracted position12so that the hook tool28does not make contact with the interior surface of the barrel74during the return push stroke. By returning the hook tool28to the retracted position12for the push stroke, the push stroke of the rifling tool10is able to occur at a much higher speed (i.e., three times the speed) than the pull stroke. As a result, manufacturing time of the barrel74may be reduced. Further yet, placing the hook tool28in the retracted position12for the push stroke so that no contact is made with the interior of the barrel74, the hook tool28is only worn on the pull stroke and not the push stroke. Further, the rifling grooves made in the interior of the barrel47are cleaner by only being cut in a single direction. For example, burring does not occur in the rifling groove due to a return cut in the opposite direction.

For each subsequent pull stroke where the hook tool28is in the cutting position14, the servo motor58may be activated to increase the height and cutting depth of the hook tool28. In turn, the hook tool28continues to cut into the interior surface of the barrel74and deepen the rifling groove with each subsequent pull stroke.

As such a rifled gun barrel is formed by securing a barrel74in the chuck arrangement76and moving the rifling tool10through the barrel74in a first direction, pull stroke and a second direction, push stroke. During the movement of the rifling tool10, the chuck arrangement76is configured to rotate the barrel74. As stated above, the cutting tool28is in the cutting position14, which may be set at any cutting depth and is adjusted during manufacturing of the barrel74, during the pull stroke causing movement of the rifling tool10in the first direction through the barrel74. In turn, the cutting tool28creates a groove in the barrel74to form the rifling. Meanwhile, the cutting tool28is in the retracted, non-cutting position12during the push stroke causing movement of the rifling tool10in the second direction through the barrel74. In turn, the cutting tool28makes no contact with the interior of the barrel and may be pulled in the second direction at a higher speed than in the first direction. Upon completion of the push stroke, the controller rotates the chuck arrangement76to ensure that the cutting tool28is aligned with the groove for the subsequent pull stroke. Each subsequent pull stroke in the first direction creates a deeper groove until the formation of the groove is complete. This process may be repeated for any number of grooves to form the rifling pattern. As previously stated, this results in the grooves only being cut in a single direction, which reduces wear on the cutting tool28and a cleaner rifling finish as there is no burring in the groove. Further yet, the increased speed of the push stroke in the second direction allows for reduction in the time for manufacturing the finished rifled barrel.

As previously mentioned, the chuck arrangement76is configured to rotate at a variable speed. For instance, the controller can rotate the chuck arrangement76at any twist rate compared to the movement speed of the rifling tool10through the barrel74. As a result, the chuck arrangement76and rifling tool10can be used to form any desired rifling pattern within the barrel74. In a non-limiting example, the chuck arrangement76can be programmed to make one full rotation for every eight inches of movement of the rifling tool10through the barrel74. Further yet, the rotation speed of the chuck arrangement76can be adjusted during the pull stroke so that the rifling pattern of the barrel74adjusts from the second end86of the barrel74to the first end of the barrel74. This results in a variable twist rifling that allows a bullet with a higher powder charge to seat within the barrel and build the spin rate of the bullet to optimize spin rate and velocity of the bullet. It is also contemplated that the speed of the pull stroke may also be adjusted.

The representative embodiment of the invention further illustrates a support bar88coupled to a work surface90of the rifling machine80. The support bar88extends vertically from the work surface90of the rifling machine80and includes an orifice92formed therein to align with an axis of the rifling tool10. The orifice92of the support bar88provides guidance for the rifling tool10as it extends through the orifice92of the support bar88during the above description push and pull strokes the rifling tool10.FIG. 11further illustrates a number of mounting holes94formed in the work table90. These mounting holes94provide variable mounting positions for the support bar88so that the rifling machine80can accommodate any length of barrel74. The rifling machine80may also include a door96to enclose the first end84of the barrel74and rifling tool10at the point of initial contact with the barrel74.

It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but includes modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.