US2567643A - Air gun loading and firing mechanism - Google Patents

Description

Sept.- 1l, 1951 L. v. KAPsA AIR GUN LOADING AND FIRING MECHANISN Filed July 2, 1946 atentec- Sept. ll, i95

2,567,643 AIR GUN LOADING AND FIRING MECHANISV Lumr Vojtch Kapsa, Prague, Czechoslovakia Application July 2, 1946, Serial No. 680,993 In Czechoslovakia August 25, 1945 3 Claims.

The present invention relates to improvements in air-guns, and in particular to an air-gun of the kind wherein a compression cylinder is arranged on the gun for co-operation with a piston by which air is pressed into the barrel behind the projectile.

It is the principal object of this invention to provide an improved air gun having novel means to feed the projectile into the gun barrel and to convey compressed air behind the projectile at the moment of iiring.

Another object of the invention is to provide an improved air gun in which the means to feed the projectile into the gun barrel also functions to provide an annular channel for the conveyance of compressed air behind the projectile at the moment of firing in a most efcient and expeditious manner.

Air-guns have already been suggested with a Acompression cylinder mounted usually behind the barrel, wherein a piston under the influence -of a driving spring drives air in front of itself, lcompresses the latter and projects it into an airlock or opening of the barrel under the projectile. Air-guns have further been suggested comprising a compression cylinder surrounding the barrel and provided with an auxiliary piston against which the main piston, together with the barrel, is projected by the influence of the driving spring.

Such a barrel transmits to the projectile its own acceleration, which is added to the acceleration of the projectile caused by compressed air. A disadvantage of such known air-guns is that of considerable diffusion owing to vibrations of the gun during the movement of the whole barrel and impacts of the barrel in forward direction, which have a tendency to pull down the muzzle even if the gun is rmly held. Moreover, compressed air does not produce the required pressure impact in the barrel, into which it is admittedthrough a number of apertures arranged on the circumference of the barrel, because this operation is accompanied by disturbing whirls and by a reduction in efficiency owing to so large a clearance.

The above drawbacks are eliminated in an air gun according to the present invention. The basic feature of the invention is the provision in the air gun of a projectile feeder which brings the projectile into a predetermined ring position in the barrel by pressing the projectile into the barrel, the front portion of the feeder being shaped so as to form at the moment of firing, together with the rear portion of the barrel, an annular channel similar to a Laval nozzle adjacent the end of the compression cylinder, for the admission of compressed air behind the projectile, to impart a centrally directed impact to the latter, while reducing to a minimum the dead space.

A further feature of the invention resides in providing that the barrel is mounted adjustably in axial direction for adjusting the dimensions of the annular channel and thereby the velocity of the projectile.

In a preferred embodiment of the invention, the front end of the barrel may be permanently fixed with respect to the sights and the gun body, so as to provide a perfectly accurate iire. The rear end of the barrel is preferably freely mounted and spaced from the gun body to be surrounded by a compression cylinder with an annular piston sliding therein. Vibrations, if any, of the rear part of the barrel at the moment of firing do not interfere at all with the accuracy .of re, because the front portion, underneath the foresight, is rigidly connected with the whole gun body system.. The gunner can easily withstand the remaining impacts by holding the gun rigidly, as they remind him of the recoil shocks of a firearm.

The spaced mounting of the rear portion of the barrel makes it possible, by suitably adapting or shaping the tip of the projectile feeder which projects from the barrel lock, to achieve a nozzlelike or annular passage from the compression cylinder into the barrel. In this way a sudden and uniform air impact, free from any interfering whirls behind the projectile is achieved, said impact extending over the whole crosssection of the bore of the barrel. With such an annular passage, the bottom of the compression cylinder may be shaped so as to achieve a complete squeezing out of the air from the cylinder in order to avoid any losses of air.

|The axial adjustment of the barrel maybe obtained in any suitable way, for instance by means of a screw thread which enables the barrel to be moved forward or backward. In this way the cross-sectional area of the annular channel may be changed.

Further objects and advantages of the invention will be apparent with reference to the following specification and drawings, in which Fig. l is a longitudinal section of a pistol air gun embodying the projectile feeder and air lock of the invention;

Fig. 2 is a detail elevation of the feeder recoil mechanism not shown in Fig. 1 for purposes of clarity;

Fig. 3 is a cross section on the line III- III of Fig. 1;

Fig. 4 is a cross section on the line IV-IV of Fig. 2; and

Fig. 5 is a cross section on the line V-V of Fig. 2.

Figure 1 shows a .pistol shaped air-gun immediately after a shot has been red and with the trigger tensioning means cocked anew. The barrel I is axially screwed into the front wall 3 of the body 4 by means ofan outer thread provided on a muzzle collar 2; the body serves also as a compression cylinder screwed onto the lock 5 of the weapon. The lock is xed. in the butt by means of a hollow screw I, which is adapted to accommodate a projectile magazine. A piston 8 is slidably mounted coaxially around the barrel in the body 4, the head 9 of the piston serving simultaneously as a-support for thefree inner end of the barrel.

vA tip of the projectile Vfeeder I protrudes from the lock'5 into the inner end of the barrel I at the moment of firing. A nozzle channel II thus provided is shown between the tip of the feeder and the end of the barrel for the admission into the barrel of compressedv air from the compression space behind thepiston and piston head 8, 9. The cross sectional area of the channel II can be adjusted by rotating the barrel by means of the muzzle collar 2 that is threaded in the front wall 3 of the body 4. In this way three basic features are provided, viz., the provision of the free inner end of the barrel, the tip of the projectile feeder protruding into this end of the barrel and a nozzle like channel between the end of the projectile feeder and the barrel.

A cocking lever I2 is pivoted immediately behind the fore sight on the front wall 3 of the body 4. The free end of the lever I2 is secured to the lock of the Weapon near the rear sight by means of a spring loaded catch I3. The upper side of the lever I2 represents in this way the line of sight. Mounted in the channel at the underside of the lever I2, as shownin detail by Figs. 1 to 3 of the drawings, is a rod I4 pivoted to the lever at I I', said rod embracing by its enlarged end I5 the body 4 and resting between its two pivots such as I I5 against struts I6. The operative ends of the struts I6 are guided in slots in the body 4 and engage a shoulder or groove on the piston body 8. During the upward movement of the cockinglever, they push the piston against the pressure ofthe drivingV spring I'I, supported at its fore end against the frontwall 3 of the body 4 and at its rear end against the head 9 of the piston 8. The pushing movement continues until a catch or sear I9 engages a collar I8 provided adjacent the head of the piston 8. The annular head 9 of the piston 8 may be sealed from both ends against the inner surfaces of the cylinder and the outer surfaces of the barrel. Mounted at the outside is a leather collar 28 tightened by means of a cap 2l tightly tted and permanently tightened by the-impacts of the piston against the lock of the barrel, which, in order to reduce shocks, is provided with an elastic buffer 22 made of semi-rigid rubber. In the interior of the head 9 is a leather ring 23 covered by a washer, against which bears the driving spring I'I. The free end of the sear I9 passes to the reararound-the trigger and engages a notch in a cylindrical safety-catch 24. The pulling-trigger V25 isprovided with a tensioning member 26, which has the form of a three arm lever, one arm being pivoted to the barrel, the opposite arm being engaged by the latch of a pawl, and the third arm protruding into the trigger space. The element 23 is spring biased upwardly and the arm extending into the trigger space is a resetting arm. The other arm of the pawl stands in engagement with an eX- tended arm of the trigger 25. Consequently, even a very light action on the trigger will cause the release by the pawl of the said arm of the member 26 so that after the trigger 25 has been pulled the pawl-engaged arm of the tensioning member 28 is projected against the free arm of the sear catch I9, to release the collar I8 of the piston, thus setting the weapon in operation.

The projectiles are removed singly, by the forward movement of the feeder I0 at each recoil movement, from the magazine, which is arranged in the hollow screw 1. The feeder moves by its tip the projectile into the barrel. The feeder I, as shown in detail in Figs. l, 2 and 5, is screwed into a carrier 2T rigidly mounted on guiding rods 23 supported in a double bearing 29. Supported around the rods 28 and resting at the rear end against an abutment on the said rods '28 there are provided springs 3G serving for the recoil movement of the feeder; the other end of each spring rests against a projection of the bearing 28. The free ends of the rods-carry tongues 3l which are guided in recesses in the body and engage the forward or left hand face of the flange provided at the end of the piston 8. At one side of the bearing 29, underneath the enlarged end or extension I5 of the rod I4 a locking lever 32 is pivoted between its ends to the barrel. The extension I5 of the rod I4 brings the element II9 of the locking lever intorengagementV with the carrier 27 of the feeder I0. Pivoted to the end of the lever 32 is a spring loaded interlock catch 33.

When the cooking lever I2 is first moved counterclockwise to cock and load the gun, the extension I5 of the arm I4 releases the level` 32 to pivot clockwise sufficiently to release the carrier 21 from engagement with the element H9. The carrier 2l then moves to the right into engagement with the spring loaded interlock catch 33 which is pivoted to the right hand end of lever 32 and loaded by spring |28. Continued movement of the cooking lever I2 will release the lever 32 to move clockwise a further amount suicient to release catch 33 from `engagement with the slot I2I of carrier 2l to enable the carrier to move under the force of springs 38 to the right and enable a projectileto be positioned in front of the projectile feeder I. A nal movement of the cooking lever I2 to the fully counterclockwise position causes the ange of the piston 8 to engage the tongues 3| of the rods 28 to move the feeder backto the left to feed and position the projectile and to again compress the springs 38. This final movement continuesuntil the carrier 21 of thefeeder engages the rear edges of the lever 32, and the sear .I9 engages the ange of the piston 8, the said ange then holding the rods 28 in forward position by means of the tongues 3l. Thus it will be seen that the interlock catch 33 prevents the feeding of a projectile unless the cooking lever is moved fully to cock and load the gun.

In order-to cock the gun the lever VI2 is rotated in the direction of the arrow A, as shown in Fig. 2 around the pivot II8. The linkl4 is pulled forward (to the left hand side) so that atenerse during the last part of `its movement, moves to.

the left hand side, by engaging the lugs 3|, the carrier 21 with the feeder I0. If the piston is fully brought home to its left hand position (cockedv position) and retained by the scar, the carrier 21 and feeder I0 remain in their left hand position, being retained by the lugs 3| being held by the piston. The cooking lever I2 may then be returned to its original position. During this return movement of the cooking lever the rear end of the member I strikes the projecting left hand portion of the lever 32 swinging the same in anticlockwise direction to the position shown in Figure 2. If a round is new ired, the piston is thrown by its spring I1 to the right hand side while the carrier 21 is retained by the abutment II9 on the lever 32 against the influence of the spring 30. If now the lever I2 is again actuated in the direction of the arrow A, the portion I5 of the rod I4 in the first phase of its movement starts moving the piston to the left, while the carrier 21 is still retained by the abutment II9. In the second phase of movement of the portion I5 the lever 32 is released as disclosed above so that it swings in the direction of the arrow B and sets free the carrier 21 which is thrown backwards to the right by its spring 3D.

During the further phase of the movement of the piston 8 to the left the latter will engage the lug 3I and pull the carrier 21 and feeder I0 forward, as disclosed above. During this operation the feeder inserts the projectile into the barrel.

Assuming now that the piston has not been fully brought to the left hand position and, therefore, not retained by the sear, it will now return together with the cooking lever rearward (to the right). During the first phase of this movement the carrier 21 will, therefore, move also backwards together with the piston, as the lever 32 is still in its rocked position in which the abutment IIS does not engage the carrier 21. The arrangement is, however, such that the portion I5 swings the lever 32 in counterclockwise direction so that the carrier is retained by the said catch 33 in a position in which'the tip of the feeder I0 still does not admit the inserting of a further projectile into the feeding channel. In order to positively prevent the carrier 21 from slipping out of engagement with the interlock catch 33, a shallow recess I2I may be provided in the rear wall of the carrier 21, if necessary.

If, after the carrier has been retained by the interlock catch 33, the gun is cocked anew, the feeder I0 cannot push another projectile into the barrel so that double loading is positively prevented.

The invention allows an overall reduction of the dimensions of the weapon, a substantial improvement of the accuracy of re, a considerable reduction in weight and an increase in efficiency. Not only the reduction in length, but also the overall reduction of dimensions achieved by the compact arrangement according to the invention is sufficiently evident from the drawings. The probable diffusion of hits with weapons of an average performance, at a range of 60 meters, and with weapons of a higher performance at a range of meters, has'v the size ofV` a circle of" 15 cm. in diameter. Efficiency With a good freshv spring which with known weapons amounts to 15% for pistol guns, and to 20% with long air-l guns, is increased according to the invention with pistols to 22% and with medium and long. Thus for instance, an air-v gun having a total weight of 2.800 kg., using aJ projectile of 0,52 g. weight, has a guaranteedV weapon to 30-35%.

muzzle velocity of Vo=220m./sec. which, however, with a good and fresh spring amounts ac tually to 270m./sec. Such velocities are, of` course, only suitable for firing in the open. A great advantage of the weapon according to thery invention also resides in the fact, that by adjusting the nozzle-like channel by a mere rotation of the barrel, the velocity, and also the impact energy of projectiles, may for the same weapon be reduced as required down to values suitable for firing in a room.

Having now particularly described and ascertained the nature of the said invention and in,

what manner the same is to be performed, I declare that what I claim is:

l. An air gun comprising in combination, a gun body, a barrel mounted in the gun body, a closure for the body mounted adjacent but spaced from the rear end of the barrel, a compression cylinder mounted `co-axially of the barrel, a spring actuated piston in the said cylinder mounted for sliding movement therein and a projectile feeder slidably mounted in the closure and adapted to feed the projectile into the barrel, said feeder having its front portion protruding in its operative forward position from the closure of the body towards and into the barrel to such an extent as to bring the projectile into a predetermined firing position and to press the same into the barrel, said front portion of the feeder being tapered and substantially point shaped so as to form in the moment of firing together with the rear portion of the barrel an annular channel adjacent the end of the compres-A sion cylinder with increasing width towards the; interior of the barrel for the admission of com-v pressed air from the compression cylinder simul-. taneously through the entire cross sectional area, of the channel behind the projectile to impart a,

centrally directed impact to the latter.

2. An air gun comprising in combination, a gun body, a barrel mounted in the said body, a closure for the body arranged adjacent the rear end of the barrel, a compression cylinder mounted co-axially `of the barrel, a piston in the said cylinder mounted for sliding movement therein, and a projectile feeder slidably mounted in the closure and adapted to feed the projectile into the barrel, said feeder having its front portion protruding in its operative forward position from the closure of the body toward and into the barrel to such an extent as to bring the projectile into a predetermined firing position, the front portion of the feeder being tapered and substantially point shaped so as to form in the moment of firing together with the rear portion of the barrel an annular channed adjacent the end of the compression cylinder with increasing width towards the interior of the barrel for the admission of compressed air from the compression cylinder simultaneously through the entire cross-sectional area of the channel behind the, projectile to impart a centrally directed impact to the latter, said barrel being mounted adjustably in axial direction in the gun body for ad justing the dimensions of.rv the annular chann co-axially of the barrel, ajspring loadedy piston'v in the Said Cylinder: mounted 'for sliding move'-Y menttherein, and a projeotile `feeder -slidably mounted in the closure and adapted to feed the projeotile into the barrel, said feeder having its i'ontportion protruding in itsoper'ative forward position toward the barrel and into the latter to such an extent as to" bringk the projecftileto al predeter'mine'dring position and to press the same into the barrel, said'front portion ofthe feeder being tapered` and substantially point" shaped so as to form in the moment of firing together with the rear portion ofthe barrel anannular channel vof increasing width towards the interior of the barrel, the relative positions at the moment of firing of the' end of the barrel and the feeder being axially adjustable to enable the dimensions of said vannular channel to be changed. fv' i* LUMEVOJTECH KAPSA.

REFEEENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 115,636 Quackenbush June 6, 1871 188,0234 Quackenbush Mar. 6, 1877 1,276,989 Syenson Aug. 217, 1918 2,066,823Y Schmeisser Jan. 26, 1937 2,303,017 Brown et al. Nov. 24, 1942 2,313,721Y Borth Mar. 16, 1943 2,450,029 Wens Sept. 28, 1948 IFOl'tEIGN` PATENTS Number Country Date '231,557 Great Britain Apr. 1, 1925 471,596 Germanygn'. Feb. 15, 1929 109,309 Great'Britain Sept. 10, 1917

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