GB2527743A - A residual pressure indexing pin assembly - Google Patents

Abstract

An indexing pin 18 for an air or gas propelled gun in which a small amount of the high pressure air or gas which is intended for propelling a projectile from the barrel is used for moving the indexing pin which in turn causes the magazine to be advanced by one indexing point.

Description

A RESIDUAL PRESSURE INDEXING PIN ASSEMBLY

The present invention relates to air guns of the type of which are fed with their ammunition by means of a magazine. More particularly the invention relates to a residual pressure indexing pin assembly which, in use, provides a means of advancing a rotary magazine without the need for complex mechanical linkages.

Airguns are made in a variety of shapes and sizes with a multiplicity of different loading and propellant systems. They have been in a state of continuous improvement since their inception in 1508 when the first mechanical bellows driven air gun was introduced.

The most significant developments are in the area of their valve arrangements, high pressure air storage systems and various methods in feeding ammunition to the breech of the gun using a magazine system of which there are many to be found in the art.

One of the earliest examples of magazine feeding systems is widely thought to have been developed by Girardoni of Austria primarily for military air rifles at the end of the 18th century. This consisted of a gravity fed tube system for spherical balls and there are many example in the art of these tuber feeder systems..

Later developments moved to rotary drum or disk systems particularly in the later half of the 20th century. Typically British Patent number GB 685700 from 1949 shows a rotary magazine system as does German Patent number DE876370 from 1953. The latter being an early example of a magazine system which was compact, circular, removable and spring loaded.

More recent developments have improved the design of the magazines so that they could reliably carry soft lead pellets instead of the solid ball ammunition for which they were first designed. However the indexing of the gun's magazine has remained a complex mechanical function requiring a number of parts for reliable operation.

Typical modern designs for ammunition feeder system in air guns are to be found in United States patent number US3782359 from 1974 which has a removable rotary magazine with a mechanical indexing system. It will be clearly seen by reference to this art that the indexing of the magazine requires a number of parts and occupies a significant amount of space within the guns mechanical system. A further design showing a completely different indexing system is to be found in United States patent number US 5150701 from 1992 which again shows a mechanical indexing system for a rotary magazine which is a major element of the design of the air gun to the extent that it would significantly affect the manufacturing costs.

It is an object of the present invention to improve upon the state of the art by teaching an entirely new concept into the design of magazine fed air guns. The present invention is intended to simplify the indexing system used to control the guns magazine by eliminating a number of the mechanical parts associated with triggering the magazine's indexing system.

According to the invention there is provided a residual pressure indexing pin which is driven from the air pressure present on the firing valve stem when firing an air rifle.

On firing an airgun a valve stem is struck by a spring driven striker which has been released from its tensioned or ready state by the trigger mechanism.

When the valve stem is struck by the striker the valve is forced open against a high pressure air reservoir. Air is then channelled past the head of the valve into the valve stem chamber and from there to the transfer port to propel a projectile from the barrel of the gun. During the firing process, a small amount of air coincidentally travels up the space between the valve-stem and its carrier, where it is ultimately stopped by a valve stem seal, or is allowed to leak to atmosphere.

In use the residual pressure indexing pin uses this, otherwise unused, pressure to drive the indexing pin upwards. This movement causes the indexing pin to connect with and drive a magazine activator pin upwards. The said magazine activator pin is contained within the guns removable magazine, and when it moves upwards it trips a rocker catch which releases the magazine allowing it to turn one indexing point to its next position when further movement is prevented by the rocker catch. The magazine contains a pre-tensioned spring which drives its rotary movement.

It will be understood that the magazine may be known by a variety of different names including bullet carrier" and it will also be understood that the magazine may carry a variety of different ammunition. The system of driving the magazine catch and therefore the indexing of the magazine by means of released air pressure may also be applied to other air or gas propelled guns including those commonly used for discharging paintballs. The invention may also be applied to other magazine systems which are not of the rotary type.

It will also be understood that the magazine may be itself propelled by clockwork, air, electrical or any other method which will cause the magazine to be driven to its next indexed position.

The invention will now be more particularly described by way of example with reference to the drawings in which figure 1 is used to illustrate the application of the invention to one type of air gun. In the illustration the moving parts are cross hatched and the invention is filled in solid black. It will be appreciated that this example is not intended to limit the invention to this particular application.

Referring now to figure 1, The gun is loaded by the action of probe 1, which moves forward from right to left of the illustration through the magazine carrier 2 and into the rotary magazine 3. As the probe passes through the rotary magazine it picks up the pellet and drives it forward into the barrel 4 and at the same time sealing the breech 6. At the same time the striker 5, is drawn back away from the valve stem 7, compressing a spring which is not illustrated.

At this point the gun is in the condition shown in the illustration which is loaded and ready to fire.

When the trigger is pulled the striker 5 is released and moves forward hitting the valve stem 7, which opens the valve at valve seat point 9. High pressure air is released and travels from the reservoir 10 through the air channel 11, into the valve chamber 15 and then past the valve seat 9, into the valve stem chamber 8.

The high pressure air then passes through the transfer port 12 and enters the breech 6 thus propelling the pellet out of the barrel 4.

A small amount of high pressure air also enters the valve stem carrier 16, but cannot escape because the carrier is sealed at point 13. The high pressure air therefore drives pin 18 upwards. The pin 18, contacts magazine activator 14, which moves catch 17 and this allows the magazine to rotate and index to the next position as soon as the probe 1 retracts out of the way.

It will be understood that there are many applications for this invention which relate to the pneumatic pin, 18 and the scope of the invention is intended to be limited only by the scope of the claims.

Claims (4)

1. CLAIMS1. A residual pressure indexing pin for use in an air or gas propelled gun, in which gun high pressure air or gas is released to propel a projectile from the barrel of the gun and where, in use, a small amount of the said released high pressure air or gas is used for the purpose of moving the said indexing pin and which moving pin activates a mechanism which allows the magazine of the said air gun to turn.
2. 2. A residual pressure indexing pin for an airgun according to claim 1 in which, in use, a small amount of the said released high pressure air or IC) gas is allowed to escape past the valve stem for the purpose of driving IC) 15 the said indexing pin upwards.

   L.C)
3. 3. A residual pressure indexing pin for an airgun according to any previous claim in which, in use, the said indexing pin which is moved by high pressure air or gas is driven upwards and which upwards moving pin activates a mechanism which allows the magazine of the said air gun to turn.
4. 4. A residual pressure indexing pin for an airgun according to any previous claim in which the said indexing pin when moved causes the magazine of the said air gun to turn by one indexing point.