Firearms – Stock or barrel connectors – Barrel to receiver
Reexamination Certificate
2000-08-25
2003-07-15
Carone, Michael J. (Department: 3641)
Firearms
Stock or barrel connectors
Barrel to receiver
C042S077000, C089S014050, C089S029000
Reexamination Certificate
active
06591534
ABSTRACT:
GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes.
FIELD OF THE INVENTION
The present invention relates to the field of artillery, and particularly to a system upgrade to a gun or cannon. More specifically, the present invention relates to a locking interface assembly that facilitates the integration of a commercially available Long Gun Barrel tube with existing gun mounts for conventional Tanks.
BACKGROUND OF THE INVENTION
The M1 Abrams tank is a main battle tank of the U.S. Army that is widely recognized as a pre-eminent armored vehicle currently available. However, the incorporation of accessories to the M1 Abrams tank can cause several problems, among which are the following:
1. Adapting a tube with a non-standard
on-conforming tube outer diameter to a conventional mounting receptacle on an Abrams tank or, more generally, a mobile armored vehicle, is a difficulty. In one particular example, a Long Gun Barrel tube currently sold through Rheinmetall GmbH, has a larger outside diameter than an Abrams mounting receptacle. A solution to this problem requires a method of joining the cannon barrel to the gun mount such that clearances and/or tolerance build-ups in the component parts do not affect the accuracy of the fit between the mount and the cannon barrel. Accuracy of the fit between the barrel and the mount ultimately affects the accuracy of the gun.
2. Incorporating a method of joining the cannon barrel (tube) to the gun mount in a manner that prevents relative axial motion (and accompanying reduction in accuracy) during firing.
3. Incorporating a means of re-tightening and re-locking components of the interface assembly in the event that they loosen after extended periods of firing. It would therefore be desirable to have a new locking mechanism that eliminates the need for machining holes for locking set screws.
4. Replacement of a coupler whose design could not be adapted to the Long Gun Barrel, is a difficulty. It would therefore be desirable to have a new coupler with a flexible multi-element design.
SUMMARY OF THE INVENTION
One feature of the present invention is to upgrade the Abrams by incorporating a new gun barrel. Specifically, the interface assembly facilitates the integration of the commercial Long Gun Barrel tube with an existing gun mount of the Abrams Tank. This invention permits a non-conforming tube configuration (Long Gun Barrel tube) to be incorporated onto the gun mount of the Abrams tank in a secure manner, such that it achieves and maintains superior accuracy when the tank is firing its gun during protracted operation and while on the move.
Another feature of the present invention is an attachment interface assembly that achieves zero (or almost zero) clearance between the tube and the mount bearing, thus preventing relative axial motion during firing.
Furthermore, the present invention allows key components of the coupler to be re-tightened and re-locked following multiple firings, thus maintaining the accuracy of the gun and avoiding safety issues.
The foregoing and other features of the present invention are realized by a multi-element interface assembly design that allows the non-conforming tube to be fitted to the mount in a precise fashion, eliminating clearances between the mount and tube, permitting re-tightening of elements that become loose during high inertial loadings. The interface assembly is comprised of a thrust nut, bearing, retaining ring, king nut, adapter, pin, nut key, locking pin, retainer pin, retaining ring key, key retainer pin and screw. It can be appreciated that the present design of the interface assembly includes a minimal number of components to achieve the advantages described herein.
The interface assembly is assembled from its constituent parts in the following manner: A retaining ring is slid over the muzzle end of the tube and is moved to an axial location on the breech side of the tube shoulder of the Long Barrel Gun tube. The tapered end of the retaining ring faces the muzzle end of as the tube. A coupling subassembly, formed of the combination of the thrust nut, bearing and two pins inserted into radial holes in the bearing, is slid over the muzzle end of the tube and seated against the tube shoulder.
Once rotated into place, the pins engage corresponding notches in the tube shoulder and prevent rotation of the bearing. With the coupling subassembly now held in place against the tube shoulder, the king nut is slid over the muzzle end of the tube and tightened on integral screw threads on the outer diameter of the tube, capturing the bearing between the tube shoulder and the face of the king nut. It should be appreciated that that the thrust nut, threaded onto the outer diameter of the bearing is still free to rotate.
With proper torquing and alignment and the addition of a locking mechanism comprising a nut key and screw, the king nut is interlocked to the bearing. The thrust nut can no longer rotate and the bearing is prevented from moving axially or rotationally with respect to the tube shoulder.
Continuing the assembly of the interface assembly assembly, the two halves of the clam-shelled adapter, incorporating serrated fingers and a tapered cross-section, are then inserted into the bore of the bearing, previously attached to the tube as part of the coupling subassembly described above. The clam-shelled design of the adapter allows it to fit tightly against the tube and obviates the need to slide an otherwise oversized component past the tube shoulder.
The adapter, inserted from the bore side of the tube, is seated against the internal shoulder of the bearing. At this point the retaining ring, previously installed on the tube, is slid axially along the tube until it engages the internal threads of the bearing. Threading the retaining ring into the fixed bearing produces an axial motion that drives the tapered section of the retaining ring across the matching taper of the adapter.
The tapered section of the bearing initially expands as it encounters the taper of the adapter. However, the inner diameter of bearing limits and then precludes outward radial expansion of tapered region of retaining ring as retaining ring continues to rotate and advance axially. With the outward expansion of the bearing inhibited, the wedging effect produced by the relative axial motion of the two tapered sections results an inward radial force on the serrated fingers of this adapter. The inward force applied to the serrated fingers of the adapter provides a uniform circumferential clamping force on the serrated fingers. The fingers distort inward and clamp down on the outer diameter the tube.
The tube is now clamped by the serrated fingers in an axial position located between the breech and the tube shoulder, providing additional stability to the interface assembly assembly. In addition, the design provides zero clearance between the tube and bearing as the opposing tapered sectioning fill the interstitial space between the outer diameter of the tube and the inner diameter of the bearing. It should be appreciated that the use of serrated fingers in the design of adapter prevents buckling of adapter as its inner diameter reduces to match, and ultimately clamp onto, the outer diameter of the tube as the retaining ring is torqued to a specified value.
A locking mechanism, composed of a key retainer pin and screw are now added. These components prevent subsequent loosening of retaining ring and adapter by interlocking the threaded retaining ring to the bearing. At this point the tube with the affixed interface assembly is ready to be assembled to the gun mount.
Using a near-standard U.S. Army assembly procedure the tube/interface assembly is assembled to the gun-mount, the thrust nut, previously threaded onto the outer diameter of the bearing advanced against the mount piston. The thrust nut is torqued to approximately 1000 ft-lbs, capturing the (mount) piston between the interface assembly and the cannon breech mechanism. The final
Gully Michael D.
Soja Michael S.
Trudeau Donald
Carone Michael J.
Moran John F.
Richardson John
Sachs Michael C.
The United States of America as represented by the Secretary of
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