Firing Mechanism For Percussion Lock Firearms

Abstract

A mechanism to replace the flash hole structure of either breech or muzzle loading percussion firearms to allow firing with metallic cartridge primers of present day commerce. The primer is enclosed by a removable cap during firing to prevent fragmentation. A relatively large flash hole is provided with a check valve to alleviate misfires and hangfires to prevent blow backs.

Description

BACKGROUND OF INVENTION

1. Field of Invention

This invention relates generally to firing mechanism for percussion lock firearms and more particularly to such a device that fires metallic cartridge primers and positively prevents blow back.

2. Description of the Prior Art

In the development of small arms prior to the metallic cartridge era, ignition or firing of a propellant charge was accomplished by ignition through a small channel communicating from the firing chamber externally through the firearm barrel. This channel, first known as a touchhole in the days when a propelling charge was ignited by touching a punk to the hole as in the ancient cannon lock, evolved successively thereafter through the matchlock, wheellock and flintlock -- all requiring some external burning type ignition -- to the percussion lock in the late seventeen hundreds. The percussion lock provided a flash type ignition by striking an unstable chemical such as a metallic fulminate to cause a flash through the touchhole and this hole thence became known as the flash hole. Soon thereafter the detonator chemical came to be contained firstly in paper caps and shortly thereafter in metallic caps. This type of ignition system became perfected in the middle of the 18th century where it was epitomized by the Sharps rifle.

Though the metallic cartridge materially changed the course of firearms development, percussion lock arms are still in use and have become increasingly popular sporting arms in modern times.

The flashhole of the percussion lock arm was necessarily of a relatively small diameter since backfire through this portal from the exploding propellant charge was controlled only by the flash hole size. The backfire normally would be directed away from a shooter by appropriate hole geometry, but nonetheless remained a hazard to shooters. The small size of the hole made it quite prone to fouling especially with the black powder loads commonly used in such arms. Fouling of the channel would prevent subsequent ignition through it to cause misfires or slow the ignition process to cause hangfires. In the latter percussion lock period, the priming compound came to be contained in a short metallic cylinder called a cap which fit appropriately about a nipple forming the external orifice of the flash hole and so positioned that it would be struck by the hammer. These caps necessarily were relatively weak to prevent fragmentation of the container during firing as the containers were generally exposed. Such a weak detonating charge cooperated with a fouled flash hole to cause further problems by way of misfires and hangfires.

The instant invention seeks to alleviate these problems in percussion lock firearms by providing particular ignition structure to replace the typical flash hole. It provides an enlarged firing channel through which an ordinary metallic rifle shell primer is fired to ignite a propelling charge. The firing channel is provided with a mechanical check valve to prevent substantial backfires and the mechanism provides complete enclosure of the primer during firing to alleviate problems caused by fragmentation. The hotter, more powerful metallic cartridge primer firing through the enlarged channel with its particular geometry does away with fouling and the consequent hangfires and misfires.

The device may be installed in existing flash hole structures by simple routine machining in existing percussion arms and may readily be adapted to conversion of the early rolling block arms to the percussion type.

SUMMARY OF THE INVENTION

My invention provides an elongate firing structure that is threadedly engaged in an appropriate channel through the breech, normally about the area of the pre-existing flash hole, of a percussion lock arm.

The structure comprises a body, preferably with a removable cap, connected for convenience by a small chain. The inner (nearest the chamber) part of the body periphery provides a threaded portion for releasable positioning in the breech of a percussion arm. The outer (most distal from the chamber) portion of the body provides a primer cup with periphery about which the cap may fit. The interior portion of the body defines a firing channel communicating axially therethrough with a one way sliding-ball type check valve in the inner end portion to prevent backfires. The cap provides a cover about the outer end portion of the body so that a primer in firing position in the primer cup is completely enclosed. A firing pin is carried in the medial part of the outer end portion of the cap to ignite a primer by impact in response to a blow from the existing hammer of a particular arm.

The mechanism may be installed in any percussion lock arm in the pre-existing threaded flash hole structure or by drilling out the channel to receive my device.

In providing such a device it is:

A principal object to provide a firing structure for percussion lock arms that uses the more powerful, hotter metallic cartridge primers of present day commerce.

A further object to provide such a structure that may be used in existing percussion lock arms either directly or after only simple machining operations.

A further object to provide such a device that has an enlarged firing channel of particular geometry communicating with the firing chamber through a sliding-ball type check valve to prevent backfires.

A still further object to provide such a device that has a releasably positionable cap to totally enclose a primer during firing to prevent fragmentation and to protect the primer, especially from moisture.

A still further object to provide such a firing structure that is of new novel design, of rugged and durable nature, of simple and economic manufacture and otherwise well adapted to the uses and purposes for which it is intended.

Other and further objects of my invention will appear from the following specification and accompanying drawings which form a part hereof. In carrying out the objects of my invention, however, it is to be remembered that its accidental features are susceptible of change in design and structure arrangement with only one preferred and practical embodiment being illustrated in the accompanying drawings as required.

BREIF DESCRIPTION OF DRAWINGS

In the accompanying drawings which form a part hereof and wherein like numbers of reference refer to similar parts throughout:

FIG. 1 is an orthographic surface view of the preferred form of my invention.

FIG. 2 is a vertical cross-sectional view of the device of FIG. 1 taken on a line 2--2 thereon in the direction indicated by the arrows.

FIG. 3 is an isometric view of the cap fastening spring clip.

FIG. 4 is an orthographic view of a specie of my invention as used in the firearm partially illustrated in FIGS. 5 and 6.

FIG. 5 is a partial orthographic surface view of a converted rolling block Remingtion showing my invention therein.

FIG. 6 is a partial cross-sectional view taken on the vertical plane 6--6 through the medial part of the rifle of FIG. 5 in the direction indicated by the arrows to show the details of my invention in such conversions.

FIG. 7 is an isometric side view of the rolling block of the rifle of FIG. 5 showing its modification.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in more detail it will be seen that my invention comprises generally body 10 defining internal firing channel 11 and carrying primer 14 which is enclosed by cap 12 having associated firing pin 13 to fire the primer upon impact.

In FIG. 1 body 10 is a generally cylindrical member of circular symmetry externally defining in its inward (nearest firing chamber) part threaded portion 15, in its medial part hexagonal nut-like portion 16 and in its outer (most distal from firing chamber) part cylindrical cap seat 17. The cap seat should provide a sliding fit for cap 12 and preferably does this by means of a slightly enlarged boss 17a. Threaded portion 15 is long enough to provide a mechanical joinder of sufficient strength within the breech portion of a barrel wherein it is threadedly engaged without appreciable loss of strength in the barrel and should define the firing channel into or nearly into the normal firing chamber of the particular arm.

Firing channel 11 is defined within the body 10 symmetrically about the body axis. The outer portion of the channel comprises cylindrical outer primer cup 18, with a depth about half that of the normal metallic cartridge primer 14, communicating by conic outwardly flaring chamber 19 to medial cylindrical firing channel 20. The firing channel in turn communicates by chamfer 21 to firing chamber facing ball-valve seat 22 in the rearward part of larger cylindrical ball-valve chamber 23 which extends through the forward end of body 10. Ball 24 is slidably carried loosely within valve chamber 23 and is of size to seat in ball-valve seat 22. The ball is maintained within chamber 23 by medial pin 41 carried forwardly of the ball by a press fit cooperating holes 25 defined in the body.

Small chain 26 is fastened by link 27 to body 10. The end of this chain communicates with spring clip 28 fastenable on cap 12 to provide a releasable attachment between the body and cap.

Cap 12 externally comprises cylinder 29 with diametrically opposed spring slots 30 in its inward part to releasably receive the arms of spring clip 28. The cap defines internal cylindrical void 31 configured to slidably fit about cap seat 17 of body 10. Firing pin hole 32, is defined in the medial part of the outer end of cap 12 to receive firing pin 13.

The firing pin is a short cylindrical element providing in its forwardmost part smaller firing proturberance 33 to impact upon a primer for detonation and in its rearward part somewhat larger body 34 projecting outwardly beyond the cap. The pin is maintained within hole 32 by a press fit therein. To cause firing in this species of my invention the outward projecting of firing pin body is struck by an arms hammer and the entire cap structure moved inwardly relative to the body to impact the firing protuberance upon a pre-placed primer.

Small vent hole 35 communicates from cap chamber 31 externally through the cap to relieve any possible back pressure through the firing channel, and allow free sliding motion of cap upon cap seat.

A species of my invention is illustrated in FIGS. 4 and 6. Here the body does not have the medial nut-like portion to aid placement, but rather provides screw driver slot 40 in the outermost part for a similar purpose. Cap seat 17 provides no enlarged boss and since this cap does not slidably move on the seat to cause firing, the cap is frictionally maintained on the seat by appropriate sizing aided by plural sots 36 in the cap wall. Firing pin 13, as shown in FIG. 6, is a separate structure carried by an associated firearm to slidably move through hole 32 in the cap to impact upon a primer. a particular installation of the specie is illustrated in the typical rolling block rifle partially illustrated in cross-section in FIG. 6.

Having thusly described the structure of my invention its operation may now be understood.

My firing mechanism may be installed in almost any percussion lock firearm. The area about the flash hole is generally already drilled and tapped but if not it is appropriately drilled and tapped to receive threaded portion 15 of the body 10 of my device. The sizing and geometry must be such that when the device is installed the hammer of the particular arm will strike the outwardly extending portion of firing pin structure 13 to cause the device to operate.

A typical installation in a Remington rolling block conversion is shown in FIG. 6 wherein my invention is seen in place to activate a charge in firing chamber 37 upon percussion activation by hammer 38. Similar installations can be made in any percussion type arm by appropriate positioning hole 39 about the originial flash hole and providing it with threads 42 to receive the threaded portion of the body of my invention, the positional requirement remaining, of course, that the hammer be capable of striking firing pin 34 to cause impact ignition of primer 14.

In use my invention is formed according to the foregoing specification and installed in a firearm as described and illustrated. Cap 12 is removed from body 10 and ordinary metallic cartridge primer 14 is inserted facing inwardly in the primer cup. The cap is then replaced upon the body in position to protect the readied primer and to fire it upon impact to firing structure 13. When the device is fired the hammer of the particular arm will communicate an impact on the rearward portion of firing pin 34 moving it sharply forwardly to strike the rearward part of primer 14 to cause ignition. In the species of FIGS. 1 and 2 the whole cap moves forwardly on the body. The ignition products of the fired primer will move forwardly through firing channel 11 and into firing chamber 37 of the firearm to ignite the propellant charge there present. As this occurs gaseous combustion products will be formed in the firing chamber to create a gas pressure which will be exerted proportionately back through the firing channel to move ball 24 outwardly against seat 22 to seal this channel and prevent exit of any substantial volume of chamber gases through the firing channel. If any back pressure is created in the firing channel before the ball valve seals, gas will pass rearwardly through that channel, with pressure partially relieved by expansion in chamber 19, to exit through vent hole 35 in cap 12, in a fashion not to injure a shooter.

From the foregoing description it is particularly to be noted that the smallest part of the firing channel 20 is mechanically limited in size only to a diameter slightly less than that of primer 14 so tht this channel may be relatively large -- from one to two-tenths of an inch in diameter -- whereas the flash hole of the typical percussion arm was only some thirty thousandths to forty thousandths of an inch in diameter. This larger hole by itself and by reason of fouling which it prevents gives a hotter ignition flame for the propellant charge to increase accuracy and reduce the possibilities of misfires and hangfires.

It is further to be noted that the primer is totally enclosed by the cap when fired not only to prevent fragmentation but also to protect the primer and keep it dry during periods of non-use.

The foregoing description of my invention is necessarily of a detailed nature so that a specific embodiment of it might be set forth as required, but it is to be understood that various modifications of detail, rearrangement and multiplication of parts might be resorted to without departing from its spirit, essence or scope.

Claims

Having thusly described my invention, what I desire to protect by Letters Patent, and what I claim is:

1. A firing mechanism for installation in a breech of percussion lock firearms, comprising, in combination:

a body having means for releasable establishment in the breech of a percussion lock firearm to communicate therethrough, the body defining an outer primer cup and an internal firing channel communicating from the primer cup through a one-way valve to the inner end, the valve preventing backfire through the internal firing channel; and

a cap adapted to seat about the outer part of the external portion of the body to cover a primer in the primer cup of the body and having an associated firing pin structure extending rearwardly thereof to fire a primer in the primer cup upon inward impact upon the firing pin structure.

2. The invention of claim 1 positioned in the breech of a percussion lock firearm, said firearm having a hammer which may deliver impact upon activation to the firing pin structure.

3. In a percussion lock firearm having a breech, a firing chamber and a hammer, a firing mechanism having a threaded channel, communicating through the breech to the firing chamber and so positioned that the hammer will impart inwardly directed impact along the axis of the channel at a spaced distance from the breech, comprising, in combination:

a body, having an inward threaded portion and an outward cap seat, defining an internal firing channel therethrough including an outer primer cup and an inward valve chamber having a seat in the outer part thereof to seat slidably carried ball to prevent back pressure; and

a cylindrical cap defining an internal chamber configured to seat upon the cap seat of the body and carrying an elongate firing pin, having an inwardly projecting firing protuberance and an outwardly projecting portion, to fire a primer in the primer cup upon inwardly directed impact upon the firing pin.

4. The invention of claim 3 further characterized by a medial part of the body outwardly of the threaded portion configured as a hexagon to aid in mechanically rotating the body.

5. The invention of claim 3 further characterized by a joinder of cap to body to prevent the cap from being removed more than a pre-determined distance from the body.

6. The invention of claim 3 further characterized by: the firing channel rearwardly of the valve seat having an outwardly increasing cross-sectional area to lessen back pressure exiting therethrough; and

the cap having a vent hole communicating therethrough.