GB1604456A - Weapons operated by compressed fluid - Google Patents

Description

(54) WEAPONS OPERATED BY COMPRESSED FLUID (71) We, NOPEK LIMITED, a British Company, of c/o Messrs. Clark Pixley, 6/10, Eldon Street, London EC2M 7LU, and ANDREW JOZEF JAWORSKI, a British Subject, of 1, Brentcot Close, London W13 8EH, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to weapons in which a projectile is forced out of the weapon by a compressed fluid, which is commonly air.

It is a well known fact that, with weapons in which air is compressed by a piston, the piston bounces back before the full amount of the energy in the compressed air has been transmitted to the projectile.

Embodiments in accordance with the invention as defined in the appended claims provide arrangements by means of which it is possible, by effectively reducing piston bounce, to increase the amount of energy transmitted to the projectile.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figs. I and 2 are diagrammatic vertical longitudinal sections illustrating parts of the operating mechanisms of respective air guns, and Fig. 3 is a diagrammatic horizontal longitudinal section illustrating a part of the operating mechanism of yet another air gun.

Referring to Fig. 1, there is shown a barrel I of an air gun, to one end of which there is attached a tubular structure 2, which in cludes a cylinder 3. Within the cylinder 3, which is coupled at one end to the barrel I, there is a piston 4. A piston rod 5, which is pivotally coupled at 7 to the piston 4, extends through a hole 8 in a member 9 arranged at one end of the tubular structure 2. Two pairs of blades 11 and 12, one blade of each pair only being visible in the drawing, are pivotally attached respectively at one end to the pivot point 7 on the piston 4 and a pivot 10 on projecting portions 13 of a bracket on the member 9. Each of a pair of headed studs, one of which studs is shown at 14 in the drawing, pivotally connects the other ends of respective ones of the blades 11 and 12 to an arm 15 of a U-shaped member 16.It will be appreciated that only one of the arms 15 is shown in the drawing. Each assembly consisting of one of each pair of blades 11 and 12, a stud 14 and an arm 15 ofthe member 16 is held. together by means of a circlip (RTM) 17. Passing freely through a hole in the base of the U-shaped member 16 is a spindle 18 which is pivoted at 19 and which carries a spring 21 urging the member 16 away from the pivot 19 against a stop 22.

In operation, a projectile is introduced into the region 23 in the bore of the barrel 1 and the gun is cocked, by means not shown, so that the piston 4 is in the solid-line position shown. The piston is then released by trigger means, not shown, in a well-known manner, so that the piston 4 is urged by the springs 6 to travel rapidly towards the dotted position 24. The spring 21 aided by the mechanical advantage of the blades 11 and 12 assists the spring 6, which loses power during its extension, in maintaining its pressure on the piston 4 during its travel.During this operation the increasing pressure in front of the piston 4 is overcome and the air in the cylinder 3 is compressed, thereby forcing the projectile along the bore of the barrel 1.

At the same time, the spindle 18 rotates about the pivot 19 in the direction of the arrow 25 until it reaches the dotted position 26. During this action, the U-shaped member 16 moves towards the free end of the spindle 18 until the pivots 7, 14 and 10 and the blades 11 and 12 are in line. This arrangement of the blades 11 and 12 holds the piston 4 firmly in position at the furthest extent of its travel from the cocked position and ensures that there is no "bounce-back" of the piston from this position. The piston is released by the action of the cocking the gun again. The amount of energy transmitted from the air that has been compressed to the projectile is thus not reduced by losses resulting from the bounce-back of the piston. Any overshoot of the arms 15 of the U-shaped member is cushioned by pads such as that shown at 27.

Reference will now be made to the embod iment of Fig. 2 in which similar parts to those already described will be referred to by the same reference numbers and will not be identified specifically.

In the embodiment of Fig. 2, there is shown a second piston 30 to which the blades 12 are pivotally connected. The piston 30 is slidable in a second cylinder 31. A pipe 32 couples the cylinders 3 and 31 pneumatically. The pneumatic coupling between the cylinders 3 and 31 enables the pressure in the two cylinders to be equalised during use and any tendency of the arrangement to operate jerkily to be minimised. The pistons 4 and 30 are shown in the cocked position and they are released by trigger means not shown to move under the influence of the spring 6 towards the ends of their respective cylinders until the blades 11 and 12 are in line, thereby preventing the pistons from bouncing back.

Another possible arrangement shown in Fig. 3 avoids the need for the spindle 18 extending at right angles to the axis of movement of the pistons.

In the arrangement of Fig. 3, the barrel 1 is attached to a tubular structure 35 which contains cylinders 36 and 37. Pistons 38 and 39 are slidably arranged within the cylinders 36 and 37 respectively and piston rods 41 and 42 extend from the pistons 38 and 39 respectively into a block 43 in which they are able to slide longitudinally. Springs 44 and 45 urge the pistons 38 and 39 away from the block 43. A pair of levers 46, one of which is visible in the drawing, is arranged on opposite sides of the block 43 and can be pivoted about a pin 47 passing through the block 43.

Pairs of blades 48 and 49, only one of each of which is visible in the drawing, are pivotally attached to the respective pistons 38 and 39 at 51 and 52 and at their other ends to the levers 46. A flap 53 is hingedly fixed to the outer surface of the cylinder 37 and the flap 33 is urged against the cylinder 37 by a spring 54 to close a hole 55 communicating with the cylinder 37. A handle 56 on the flap 53 enables the flap 53 to be raised and the hole 55 to be opened for communication with the cylinder 37.

In operation, the gun is cocked by holding the flap 53 open by means of the handle 56 in order to allow air to enter the cylinder 37 and destroy any vacuum therein, and the pistons are restored, by means not shown, to the position shown in the drawing. Upon release of a triggering means, not shown, the springs 44 and 45 urge the pistons 38 and 39 towards the ends of their respective cylinders. The piston 39 forces the air in the cylinder 37 out of the cylinder through the hole 55 against the force of the spring 54.The spring 54 is of such a strength that it provides an equalising force with that exerted by the projectile in the barrel I against the force of the air compressed in the cylinder 36 and since the flap valve 53 prevents air from returning into the cylinder 37 throught the hole 55, a vacuum is produced in the cylinder 37 which holds the piston 39 at the end of its travel and prevents it from bouncing back. Since the piston 39 is coupled to the piston 38 via the arrangement of levers 48, 46 and 49 the piston 38 is also prevented from bouncing back and the maximum amount of energy in the air compressed in the cylinder 36 is transferred to the projectile. In practice the dimensions of the arrangements shown may be considerably different from those in the illustrations.For example the travel of the pistons 38 and 39 in Figure 3 may be only ) to 1 inch and block 43 can be of sufficient length to accommodate the full travel of pistons 41 and 42.

It will be appreciated that, although the invention has been described with reference to particular embodiments, variations and combinations of the arrangements shown may be made within the scope of the invention as defined by the appended claims.

WHAT WE CLAIM IS: 1. A weapon from which a projectile is ejected by means of a fluid compressed by a piston under the influence of a spring including means to minimise piston bounce which includes first and second pivotally interconnected levers, the first lever being pivotally connected to the piston and the arrangement being such that the levers are locked substantially in line when the piston is at the maximum extent of its travel.

2. A weapon as claimed in claim 1 in which the second lever is pivotally connected to a point which is fixed relative to the piston.

3. A weapon as claimed in claim 1 including a second piston wherein the means to minimise piston bounce includes first and second pivotally inter-connected levers, the first lever being pivotally connected to the first mentioned piston and the second lever, being pivotally connected to the second piston, the arrangement being such that the levers are locked substantially in line when the first mentioned piston is at the maximum extent of its travel.

4. A weapon as claimed in either claim 2 or claim 3 including a second spring arranged to urge the first and second levers into line.

5. A weapon as claimed in claim 3 or claim 3 and claim 4 including means to equalise the forces acting against the movement of the first and second pistons.

6. A weapon as claimed in claim 3 including means to enable a cylinder associated with the second piston to be exhaused and to provide a vacuum therein, whereby any tendency for the first mentioned and second pistons to bounce is minimised.

7. A weapon as claimed in claim 1

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. iment of Fig. 2 in which similar parts to those already described will be referred to by the same reference numbers and will not be identified specifically. In the embodiment of Fig. 2, there is shown a second piston 30 to which the blades 12 are pivotally connected. The piston 30 is slidable in a second cylinder 31. A pipe 32 couples the cylinders 3 and 31 pneumatically. The pneumatic coupling between the cylinders 3 and 31 enables the pressure in the two cylinders to be equalised during use and any tendency of the arrangement to operate jerkily to be minimised. The pistons 4 and 30 are shown in the cocked position and they are released by trigger means not shown to move under the influence of the spring 6 towards the ends of their respective cylinders until the blades 11 and 12 are in line, thereby preventing the pistons from bouncing back. Another possible arrangement shown in Fig. 3 avoids the need for the spindle 18 extending at right angles to the axis of movement of the pistons. In the arrangement of Fig. 3, the barrel 1 is attached to a tubular structure 35 which contains cylinders 36 and 37. Pistons 38 and 39 are slidably arranged within the cylinders 36 and 37 respectively and piston rods 41 and 42 extend from the pistons 38 and 39 respectively into a block 43 in which they are able to slide longitudinally. Springs 44 and 45 urge the pistons 38 and 39 away from the block 43. A pair of levers 46, one of which is visible in the drawing, is arranged on opposite sides of the block 43 and can be pivoted about a pin 47 passing through the block 43. Pairs of blades 48 and 49, only one of each of which is visible in the drawing, are pivotally attached to the respective pistons 38 and 39 at 51 and 52 and at their other ends to the levers 46. A flap 53 is hingedly fixed to the outer surface of the cylinder 37 and the flap 33 is urged against the cylinder 37 by a spring 54 to close a hole 55 communicating with the cylinder 37. A handle 56 on the flap 53 enables the flap 53 to be raised and the hole 55 to be opened for communication with the cylinder 37. In operation, the gun is cocked by holding the flap 53 open by means of the handle 56 in order to allow air to enter the cylinder 37 and destroy any vacuum therein, and the pistons are restored, by means not shown, to the position shown in the drawing. Upon release of a triggering means, not shown, the springs 44 and 45 urge the pistons 38 and 39 towards the ends of their respective cylinders. The piston 39 forces the air in the cylinder 37 out of the cylinder through the hole 55 against the force of the spring 54.The spring 54 is of such a strength that it provides an equalising force with that exerted by the projectile in the barrel I against the force of the air compressed in the cylinder 36 and since the flap valve 53 prevents air from returning into the cylinder 37 throught the hole 55, a vacuum is produced in the cylinder 37 which holds the piston 39 at the end of its travel and prevents it from bouncing back. Since the piston 39 is coupled to the piston 38 via the arrangement of levers 48, 46 and 49 the piston 38 is also prevented from bouncing back and the maximum amount of energy in the air compressed in the cylinder 36 is transferred to the projectile. In practice the dimensions of the arrangements shown may be considerably different from those in the illustrations.For example the travel of the pistons 38 and 39 in Figure 3 may be only ) to 1 inch and block 43 can be of sufficient length to accommodate the full travel of pistons 41 and 42. It will be appreciated that, although the invention has been described with reference to particular embodiments, variations and combinations of the arrangements shown may be made within the scope of the invention as defined by the appended claims. WHAT WE CLAIM IS:

1. A weapon from which a projectile is ejected by means of a fluid compressed by a piston under the influence of a spring including means to minimise piston bounce which includes first and second pivotally interconnected levers, the first lever being pivotally connected to the piston and the arrangement being such that the levers are locked substantially in line when the piston is at the maximum extent of its travel.

2. A weapon as claimed in claim 1 in which the second lever is pivotally connected to a point which is fixed relative to the piston.

3. A weapon as claimed in claim 1 including a second piston wherein the means to minimise piston bounce includes first and second pivotally inter-connected levers, the first lever being pivotally connected to the first mentioned piston and the second lever, being pivotally connected to the second piston, the arrangement being such that the levers are locked substantially in line when the first mentioned piston is at the maximum extent of its travel.

4. A weapon as claimed in either claim 2 or claim 3 including a second spring arranged to urge the first and second levers into line.

5. A weapon as claimed in claim 3 or claim 3 and claim 4 including means to equalise the forces acting against the movement of the first and second pistons.

6. A weapon as claimed in claim 3 including means to enable a cylinder associated with the second piston to be exhaused and to provide a vacuum therein, whereby any tendency for the first mentioned and second pistons to bounce is minimised.

7. A weapon as claimed in claim 1

substantially as described herein with reference to Fig. 1, Fig. 2 or Fig. 3 of the accompanying drawings.