Ordnance – Automatic – Receiver closures and/or breech block return means
Reexamination Certificate
2000-05-24
2002-07-16
Johnson, Stephen M. (Department: 3641)
Ordnance
Automatic
Receiver closures and/or breech block return means
C089S198000, C089S044010
Reexamination Certificate
active
06418833
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to auto-loading firearms, and more particularly to an improved auto-loading system including an improved recoil spring assembly.
2. Background
There exists two distinct types of auto-loading shotguns: recoil operated and gas operated. In each case, forces resulting from the discharge of the firearm are controlled to some extent and employed in cycling the breech bolt assembly in order to discharge a spent round and reload the gun following discharge of the shell. In each case, the auto-loading cycle occurs in two segments. The first segment of the auto-loading cycle is the discharge of the spent round and cycling of a subsequent round from the magazine to a positioning mechanism for loading during the second segment. The first segment is characterized by the movement of the breech bolt assembly in a rearward direction. Energy from the movement of the breech bolt assembly to the rearward position in the receiver is stored in both the case of the recoil operated auto-loading firearm and the gas operated auto-loading firearm in a magazine spring which surrounds the magazine tube and in a recoil spring located in the butt of the firearm. The recoil spring is commonly housed in a recoil spring tube and is acted upon by a link which attaches to an action bar which in turn attaches to the slide portion of the reload mechanism.
The second segment involves the movement of the subsequent round by the positioning mechanism into the breech for movement to the battery position. The second segment is characterized by the movement of the breech bolt assembly in a forward direction. In the second half of the auto-loading cycle, energy stored in the recoil spring is utilized to move the breech bolt assembly forward, lifting the elevator in order to position the next round for firing, thereby completing the auto-loading cycle.
The first type of auto-loading firearm achieves the auto-loading cycle by employing a discharge and loading mechanism which is activated by the recoil of the gun. In this case, when the shotgun is fired, a resulting force is exerted against the breech bolt assembly driving the bolt towards the rear of the firearm within the receiver.
The second type of auto-loading system, the gas operated auto-loading firearm, achieves the auto-loading cycle by employing a loading mechanism which is activated by gas generated by the discharge of the firearm. When a round is fired, gas generated by the discharge of the firearm is diverted to a cylinder which is commonly arranged about the magazine tube, through a small port in the barrel of the firearm, causing a piston to move in a rearward direction carrying the breech bolt assembly to a rearward position.
The prior art relating to auto-loading firearms is concentrated for the most part on the mechanism which enables the function of the first half of the cycle, that is moving the breech bolt to the rearward position in the receiver and discharge of the spent round.
In a gas operated auto-loading firearm, the structure relating to the first half of the cycle includes the cylinder with its associated piston which typically surrounds the magazine tube. The cylinder typically attaches to the bolt by means of an action bar. Gas from the discharge of the firearm is directed to the cylinder and against the piston through a gas port located in the barrel of the firearm. This structure, together with improvements thereto, has been disclosed broadly in the prior art. See generally Browning, U.S. Pat. No. 2,211,405; Hillberg, U.S. Pat. No. 2,909,101; Kelly et al., U.S. Pat. No. 3,200,710; Vartanian, U.S. Pat. No. 3,580,132; Zanoni, U.S. Pat. No. 3,848,511; Liedke, U.S. Pat. No. 4,102,242; Grehl, U.S. Pat. No. 4,505,183 and Norton et al., U.S. Pat. No. 5,872,323.
The fact that such a great deal of attention has been paid to that structure which affects the movement of the breech bolt assembly in the rearward direction within the receiver and so little attention has been afforded that mechanism which returns the breech to the forward, or battery, position within the receiver, is somewhat a matter of curiosity. This fact is of particular interest considering that it is within the second half of the cycle that jamming of the firearm most often occurs. Experience has shown that jamming occurs for a number of reasons, including the presence of dirt and debris including rust and corrosion within the various moving component parts of the firearm. Specifically, it has been found that corrosion and wear within the recoil tube affects both the cycling speed and performance of the firearm. Additionally, jamming may occur when an attempt is made to cycle the action when loads are fired which generate chamber pressures which are greater or lesser than those for which the gun is set up. It is often the case, in firearms that are manufactured according to the prior art, that a variety of interchangeable recoil springs having a variety of configurations may be employed in order to effect a smooth transfer of the breech bolt assembly to the battery position depending on the size and configuration of the particular load being fired. Jamming may occur when recoil spring characteristics and the load are mismatched.
Additionally, it has been observed that recoil spring tube assemblies according to the prior art have employed relatively light weight recoil springs, that is springs having relatively low spring rates, less than 0.50, where spring rate is defined as the load in pounds required to produce one inch of linear deflection in the spring. Recoil springs having low spring rates have a tendency, when subjected to the repeated cycling of an auto-loading firearm, to buckle or deform reducing substantially their efficiency. Additionally, light springs tend to absorb recoil energy inefficiently oftentimes allowing the stem of the recoil spring follower to bottom out against the rear end of the recoil spring tube causing damage to the recoil spring tube assembly.
Likewise, it has been observed that recoil spring tube assemblies according to the prior art have employed followers that have relatively low mass. It has been observed that the combination of springs having relatively low spring rates with followers that have relatively low mass results in a mechanism which lacks the required inertia to cycle in a sure and consistently repeatable manner regardless of the load being chambered or the degree of foreign matter within the various sub-assemblies of the firearm.
Followers manufactured according to the prior art are configured having circumferential surfaces that bear against the internal bore of their respective recoil spring tubes that are flat, relatively wide and unpolished. Additionally, it has been observed that followers, manufactured according to the prior art and formed of materials that are not corrosion resistant begin to perform the function of sliding within the recoil spring tube less satisfactorily with age or when exposed to moisture or even ambient humidity. Additionally, it has been observed that materials may be used for forming the follower which are unsuitable or mismatched with the materials employed in forming the recoil spring tube. Again this may result in less than optimum or deteriorating performance. It has been observed that in auto-loading firearms manufactured according to the prior art, followers have a tendency to gall or abrade when subjected to the repetitious sliding creating even greater friction and resistance between the follower and the internal bore of the recoil spring tube further decreasing the efficiency of the recoil spring tube assembly and therefore the auto-loading capability of the firearm.
SUMMARY OF THE INVENTION
According to the present invention, a recoil spring tube assembly for an auto-loading firearm includes a recoil spring tube having first and second ends with the first end being closeable to retain a recoil spring which is inserted within the recoil spring tube. The recoil spring tube assembly also includes a recoil sprin
Holland Joseph W.
Johnson Stephen M.
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