Firearms – Safety mechanism
Reexamination Certificate
1999-09-10
2001-06-26
Jordan, Charles T. (Department: 3641)
Firearms
Safety mechanism
C042S070110
Reexamination Certificate
active
06250008
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to a safety plug which is inserted into the firing chamber of a firearm, such as a fully automatic or semi-automatic firearm, a bolt-action rifle, or a pump-action shotgun. More particularly it relates to a firearm safety plug which provides enhanced visual confirmation that the plug is inserted in the firing chamber and improved functional working within the chambers of numerous firearm types.
BACKGROUND
Conventional firearms need safety features to protect the user from accidental firings. Accidental firings typically happen when the user is unaware that a live ammunition cartridge is loaded in the firing chamber. Safety procedures normally require opening the chamber to make a visual inspection to ensure that it is not loaded with live ammunition. A safety plug placed in the firing chamber with a tab extending through the breech for visual and tactile confirmation eliminates the need to open the firing chamber to make such an inspection.
Other safety plugs have been designed to be loaded in the firing chamber of a weapon, and provide visual identification. But structural limitations of some firearms have prevented their effective use in this regard. These safety plugs need to be conveniently extractable from the firing chamber to allow a live ammunition cartridge from the firearm's magazine to be quickly loaded. They also need to securely fit into the firing chamber without falling out. Safety plugs that either jam or fall out of the firing chamber render their functionality useless and potentially dangerous.
Also, prior art safety plugs have provided limited visible indications of their presence in the firing chamber. Low light and night time conditions are particularly troublesome for such indication. The visual indication should be conspicuous and easily seen in any light condition.
Another disadvantage of prior art safety plugs is the inability to efficiently mass produce a reliable product. Prior art safety plugs having an annular rim for being grasped by the firearm's ejector are typically constructed from two separate parts—a forward part which is usually constructed of a material such as nylon or plastic, and a rearward part with an ejector rim which is usually constructed of machined brass. The manufacturing process involved with machining the brass base and joining it with the plastic forward section is labor intensive, expensive, and highly subject to manufacturing error due to the fine tolerances that are required (usually {fraction (1/1000)}th inch). Manufacturing the forward and base sections as a single plastic or nylon part would be desirable, but doing so has heretofore not been a practical option because the resultant one-piece construction is generally unable to withstand the mechanical rigors of being inserted and ejected from the firearm, particularly when the safety plug is ejected multiple times.
Therefore, there is a need for an effective and reliable safety plug that can be mass produced efficiently. The safety plug should provide a visual confirmation in all light conditions and improved functionality within the firing chambers of numerous firearm types.
SUMMARY
With regard to the foregoing, the invention provides a safety plug with a tab for visual confirmation of its presence in the firing chamber of a firearm such as a semi-automatic firearm, a bolt-action rifle, or a pump-action shotgun. The safety plug consists of a cylindrical body which is substantially the same length as an ammunition cartridge commonly used in the particular weapon. The safety plug has a diameter which is less than the firing chamber bore. The cylindrical body has a nose end and a base end. The nose end is inserted first into the empty firing chamber. The nose end is fabricated from a rigid non-abrasive material. The base end may be fabricated from the same piece of material as the nose end or from a separate piece of material and attached to the nose end. The base end has rim with a larger diameter than the cylinder body with a forward edge and a rearward edge. The forward edge is engaged by the extractor of the firearm in the same manner that the rim of an ammunition cartridge is engaged and extracted from the firing chamber. A tab is mounted between the nose end and the rim and extends outwardly from the cylindrical body substantially perpendicular to the cylindrical body's central axis. Therefore, the tab extends through the breech of the firearm for visually indicating its presence in the chamber.
The safety plug includes a beveled surface on the extremity of the rim. The beveled surface is formed such that the diameter of the rim at the rearward edge is less than the diameter of the rim at the forward edge. This beveled surface improves the functionality of the safety plug by preventing it from catching on the top ammunition cartridge in the firearm magazine during an extraction sequence. Such interference can cause the safety plug to jam inside the firing chamber, thereby preventing the ammunition cartridge from loading. The inner portion of the rim has a sharply defined perpendicular edge to enhance extractor function.
Pump-action shotguns do not have a spring loaded bolt carrier which would otherwise hold the safety plug in place. One embodiment of the invention overcomes that difficulty. The outer surface of the nose end includes an annular lip having a larger diameter than the rest of the cylindrical body. The annular lip creates a compact fit into the firing chamber of a shotgun thereby inhibiting relative motion between the firing chamber and the safety plug. Therefore, the safety plug is held in the firing chamber and does not fall out. Another embodiment of the annular lip includes a collet to allow the firing chamber to resiliently compress the annular lip for a more compact fit. This design also prevents jamming which might otherwise occur with temperature extremes that cause contraction of the barrel and firing chamber.
Another embodiment of the present invention includes a luminescent element located on the exterior surface of the tab. The luminescent element is placed so that it may be easily identified by the user of the weapon. The luminescent element improves the tab's visibility in night time or other low light conditions. Encased tritium is a common luminescent element that may be easily used.
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Chambers Troy
Jordan Charles T.
Luedeka Neely & Graham P.C.
Safe Tech, Inc.
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