Patent Publication Number: US-2011056471-A1

Title: Projectiles

Description:
This invention relates to projectiles. 
     It is known to fire projectiles from compressed gas launchers. Such projectiles have been suggested to carry loads such as lines or inflatable booms mounted on the end of a line carrying a projectile; the projectile is launched from the launcher, thus drawing out the line and hence the load. Such a launching system can be used to launch an inflatable system such as is described in our PCT patent application PCT/GB2008/001465, the entire disclosure of which is incorporated by reference. 
     However, the range of such projectiles and the load they can carry is limited by the impetus given to the projectile by the launcher. 
     According to a first aspect of the invention, there is provided a projectile arranged to be launched from a launcher, the projectile comprising a source of compressed gas and control means for controlling the release of the compressed gas, in which the control means is arranged so as to release the compressed gas in response to the launching of the projectile from the launcher. 
     Thus, the compressed gas can be used to exert a thrust on the projectile by ejecting the compressed gas in the opposite direction to the travel of the projectile; in effect, the projectile becomes a rocket. 
     Preferably, the launcher is a compressed gas launcher. The source of compressed gas may comprise a reservoir of compressed gas. The compressed gas of which the source is a source and the compressed gas used by the launcher may comprise compressed carbon dioxide (CO 2 ), compressed air, or any other gas that may conveniently stored and released at significantly above local atmospheric pressure. 
     The control means may release the compressed gas in response to the application of gas pressure by the launcher as part of the launching of the projectile. Alternatively or additionally, the control means may release the compressed gas in response to the acceleration of the projectile upon launch. Either of these features provides automatic actuation of the “second stage” of the projectile without the need for trailing lines or fuses. 
     However, the control means may be arranged such that the release of the compressed gas is delayed until after the projectile has cleared the launcher; this is safer for the operator of the launcher and leads to more predictable launching. Where the control means is arranged to release the compressed gas in response to the application of gas pressure, the control means may also be arranged such that the application of gas pressure is required in order to release the compressed gas, but the application of gas pressure must abate before the compressed gas is released. As such, both an initial application of gas pressure and an abatement of the applied gas pressure may be required in order for the control means to release the gas. 
     The control means will typically comprise a valve. The valve may comprise a diaphragm and a piercing body, with the control means being arranged such that application of gas pressure by the launcher forces the piercing body into the diaphragm so as to pierce the diaphragm. Thus, the compressed gas can be released upon an application of gas pressure. 
     The valve may comprise a blocking element, typically the piercing body, which blocks the release of compressed gas while gas pressure is applied to the projectile by the launcher. It may be arranged so as to allow the release of compressed gas on abatement of the applied gas pressure. 
     The blocking element and piercing element may form a single valve body, which is mounted biased away from the diaphragm, typically by a resilient element such as a spring. 
     The valve body may be mounted in a bore in the projectile through which gas pressure can be applied by the launcher in use. The bore may have a first cross section at a first position occupied by the valve body when the piercing element is piercing the diaphragm; and a second cross section at a second position occupied by the valve body without the application of gas pressure by the launcher, the second cross section being larger than the first cross section. Preferably, the valve body fills the first cross section so as to block the bore at the first position but is smaller than the second cross section and hence allows the passage of compressed gas in the second position. The valve body may be forced into the second position, in use, by the compressed gas released from the source. 
     Typically, the bore extends from the valve to the rear of the projectile, forming an exit for the compressed gas. The bore may comprise an expansion chamber at the exit of increased cross section compared to the bore adjacent thereto. This expansion chamber allows the exit velocity of the compressed gas to be controlled, by changing the size and shape of the chamber. In particular, the expansion chamber may taper towards the exit, which allows for a (typically slight) compression of the compressed gas before it reaches the exit. 
     The bore may be provided with ridges, arranged so as to cause vortices in the compressed gas as it is released from the projectile. There may be ridges in the wall of the expansion chamber, nearer to the exit than the distal end of the chamber. There may be ridges in the wall of the bore adjacent to the expansion chamber. Thus, turbulence is induced, which has been found to increase the thrust available from the amount of gas expelled. 
     The projectile may be arranged to pull a load, such as a load mounted on a line. 
     The projectile may comprise a head portion, comprising the source of compressed gas, and a neck portion extending rearwards from the source of compressed gas. The bore may be formed in the neck portion. The head portion and so the source of compressed gas may be interchangeable for other such head portions; the head portion may engage the neck portion by a releasable coupling, such as a screw thread. Alternatively, the source of compressed gas may be rechargeable after use. 
     According to a second aspect of the invention, there is provided a projectile launching system comprising a compressed gas launcher and a projectile according to the first aspect of the invention. 
     The launcher may be arranged so as to provide a charge of compressed gas so as to launch the projectile. The charge may be applied to the control means so as to cause the release of the compressed gas from the source. Where the projectile comprises a bore, the compressed gas may be applied to the bore. 
    
    
     
       There now follows by way of example an embodiment of the present invention, described with reference to the accompanying drawings, in which: 
         FIG. 1  shows a side elevation of a projectile according to the present invention, fitted into a launcher shown schematically; 
         FIG. 2  shows a cross section through the rear section of the projectile of  FIG. 1 ; 
         FIG. 3  shows the valve body of the projectile of  FIG. 1 ; and 
         FIG. 4  shows the expansion chamber of the projectile of  FIG. 1 . 
     
    
    
     A projectile  10  according to an embodiment of the invention is shown in the accompanying drawings. The projectile comprises a head portion  1  being a compressed gas cylinder of a suitably aerodynamic shape and a neck portion  2  extending rearwardly (when considering the direction of travel of the projectile) from the head portion  1 . Both portions are elongated along the direction of travel. 
     In use, the cylinder is charged with compressed gas to a pressure of around 250-300 bar. The projectile  10  is fitted into a launcher  12 . The launcher  12  comprises a further source of compressed gas  14 , and a launch tube  16  for the projectile  10 . The launch tube  16  surrounds the rear end of the neck  2  of the projectile  10 . The launcher  12  is held by a user by means of a handle  18 , and can be activated by means of trigger  20 . On activation of the launcher  12 , a charge of compressed gas at significantly above local atmospheric pressure is released into the launch tube  16 . This charge is allowed to expand in the launch tube, forcing the projectile  10  out of the launch tube  16 , thereby launching the projectile  10 . 
     The effect of the launch can be demonstrated with particular reference to  FIG. 2  of the accompanying drawings. The compressed gas cylinder forming the head portion  1  engages the neck portion by means of a screw thread  3 . The compressed gas cylinder  1  has a metal diaphragm  4  sealing the rear end of the cylinder. When the cylinder  1  is secured to the neck portion  2  by means of the screw thread  3 , the diaphragm  4  is exposed to an internal bore  5  passing through the neck portion along the direction of travel to the rear end of the projectile, where the bore  5  forms an exit  22 . Typically, the neck portion will be cylindrical, with the bore coaxial with the neck portion. The bore  5  is generally cylindrical, but with steps in cross section. 
     A valve body  6  is mounted in the bore  5  adjacent to the diaphragm  4 . The valve body  6 , which can be seen in more detail in  FIG. 3  of the accompanying drawings, comprises a body portion  30  and a piercing portion  32 . 
     In one embodiment, the piercing portion  32  comprises a needle. However, it has been found that needles can stick in the diaphragm. In the preferred embodiment shown, the piercing portion  32  comprises a circular, or slightly off-circular cutting tool, comprising a hollow tube cut at an angle to its axis, so as to define a point which initially pierces the diaphragm  4 , with the remainder of the cut face of the tool acting to cut out a circle (or substantially circular ellipse) out of the diaphragm. Because of the shape of the cutting tool, this circle will remain attached to the diaphragm, but folded back on itself. Thus, the cutout portion will not be released to interfere with the operation of the rest of the device. 
     The valve body is held in position in the bore  5  by two springs  7   a ,  7   b . The spring  7   a  acts to bias the valve body  6  away from the diaphragm, whereas spring  7   b  acts to prevent the valve moving too far backwards along the bore  5 . 
     The bore  5  has two different cross sections around the valve body  6 . In a first position  8  adjacent to the diaphragm, the cross section is the same as (or only slightly larger than, in order to allow for manufacturing tolerances) that of the body portion  30  of the valve body  6 . In a second position  9  behind the first position, the cross section is greater than that of the first position  8 . The effect of this is as follows. 
     When the launcher  12  applies the charge of compressed gas to the projectile  16 , the pressure will travel up the bore to the valve body  6 . The pressure will act on the curved rear face of the valve body  6  and force it, against the force of spring  7   a  towards the diaphragm  4 . The piercing portion  32  will then be pushed through the diaphragm  4 , piercing it. Accordingly, the diaphragm  4  will no longer seal the cylinder  1 . 
     However, the body portion  30  of the valve body  6  is occupying the first portion of the bore  5 . The body portion  30  occupies the entire cross section of this part at this time, and so the valve body  6  blocks the release of compressed gas from the cylinder  1 . Typically, the charge would be of greater pressure than the pressure in the cylinder  1 . 
     An effect of the charge is, as discussed above, to launch the projectile  10  from the launcher  12 . As the projectile leaves the launcher, the gas pressure due to the charge in the bore will decrease. Eventually, the spring force from spring  7   a  and the pressure in the cylinder  1  acting on the valve body  6  will be sufficient to overcome any remaining force on the valve body  6  due to the pressure due to the charge and the spring force from spring  7   b  in order to move the valve body  6  to the second position  9 . 
     In this position, the body portion  30  does not block the release of compressed gas from the cylinder  1 . Accordingly, the compressed gas is released from the cylinder and passes along the bore  5 , passing the valve body  6  and exiting the projectile  10  through the exit  22 . This release of compressed gas provides the projectile with thrust, thereby increasing its load carrying capacity and its range. 
     It can therefore be seen that the valve body  6  working in the bore  5  and the diaphragm  4  together define a valve  23 , which releases the compressed gas in the cylinder  1  only after the application of gas pressure thereto followed by an abatement of that pressure. The effect of this is that the compressed gas is only released once the projectile  10  has left the launcher  12 . This is both safer for a user of the device, and also can lead to more predictable launches. 
     As can be seen in  FIG. 4  of the accompanying drawings, which shows the bore  5  around the exit  22 , the bore  5  is provided with an expansion chamber  24  adjacent to the exit  22 . The expansion chamber is of greater cross section than the section  26  of bore  5  leading to the expansion chamber from the cylinder  1 . However, the expansion chamber has a slight taper  25  towards the exit  22 . 
     That section  26  of bore  5  is provided with ridges in the walls of the bore. Ridges  28  are also provided in the expansion chamber  26  at a portion  29  towards the rear end of the expansion chamber  24 . These ridges  27 ,  28  cause turbulence in the compressed gas being released from the cylinder. 
     The combined effect of the size and shape of the expansion chamber  24 , and in particular the taper  25 , and of the ridges  27 ,  28  is to allow the speed and flow mode (turbulent as opposed to laminar flow) of the compressed gas to be controlled as it exits the projectile. Thus, the thrust available from the necessarily finite amount of compressed gas held within the cylinder  1  can be maximised. 
     The neck  2  of the projectile  10  also has two mounting holes  36  for mounting a line thereto. The holes  36  pass through the neck portion adjacent to, but not passing through, the expansion chamber  24 . In order not to unbalance the projectile, two loops of line will generally be used each passed through one of the holes  36 . The line can be used to project a load, such as the boom described in our PCT patent application no PCT/GB2008/001465. 
     In this embodiment, the compressed gas stored in the cylinder  1  and used as the charge by the launcher  12  is carbon dioxide (CO 2 ); compressed air has also been successfully employed, and has the advantage of being more abundant and also cheaper. There is no reason why other suitable gasses could not be employed; the two devices need not even operate using the same gas. 
     Once the projectile  10  has been launched, the natural buoyancy of the cylinder  1  will mean that the projectile may float. 
     The screw thread  3  employed means that the cylinder  1  may be replaced after use. In a supplementary embodiment, the cylinder  1  may be refillable instead, or in addition. 
     There now follows as part of this description the description of the inventor&#39;s previous application, to aid in the understanding of the present invention. 
     VAC2 Pro Dep Sys 
     The present invention relates to an innovation to aid the launching of any piece of apparatus (of any kind) into a position remotely to the operator. The projectile described can be used for improving the launch distance for recovery of individuals from the water or other use with deployment of lines or oil chemical spill control systems. The projectile itself is intended to be deployed principally with compressed air from a launcher containing the first stage of compressed air which is released to provide the kinetic energy for both initial launch of the projectile and the priming of the internal second stage of Co2 powered thrust activation of the inflation system. Principally the projectile is launched out of the launching tube on the launcher providing initial flight but once the projectile leaves the launch tube the internal Co2 jet system activated giving further thrust force to the projectile and greater distance capabilities. 
     It is known to project a recovery line into the sea via a launcher as to deploy any attached apparatus such as rope lines or other. It is now proposed not only: A projectile device for vastly improving the deployment capabilities of any apparatus connected to the projectile but a projectile with its own internal propulsion system similarly based on compressed air as is the launcher. Further to this the propulsion system inside the projectile is initiated (triggered) by the blast force of the first stage launch by means of an internal activation system as to ensure perfect second stage initiation via kinetic energy produced under the impact of launch conditions. 
     For example. The projectile is loaded into the launcher ready to launch. Stowed at the front of the launcher is an inverted Co2 supply of gas or compressed air (or other medium). On launch of the projectile massive amounts of pressure are instantly applied behind the projectile which forces it out of the launching tube into the air. The internal pressure in the launch tube mentioned is allowed to rush up inside of the projectile and strike a pre positioned piston supporting a pin which in turn is forced into the cylinder effectively piercing the cylinder. While the projectile is travelling out of the tube pressures are still being applied to the piston until the projectile exits the launch tube. At the point when the projectile clears or exits the launch tube the pressure inside the neck of the projectile will dissipate and at this point the piston is pushed out of the cylinder releasing the Co2 (for example.) The pressure inside the cylinder then is allowed to flow through the neck of the projectile into an expansion chamber where expansion takes place and helps to thrust the projectile from this internal propulsion system. 
     This projectile system can now be used for launching much heavier payloads, lines or other such trailing apparatus such as a vessel immobiliser further distances than ever before due to the fact two propulsion systems are combined into one giving rise to the benefits of both in one projectile system. 
     Difficulties have been experienced in ensuring the payloads are launched out far enough away from the launching point as to reach the required distance as to be effective in performing the job intended. For example launching a recovery system out far enough to an individual in the water as in the MOB situation. 
     The object of the present invention is to improve the function and launch capabilities of a standard pneumatic line thrower under operation by adding to the projectile a second stage propulsion system to provide much more power by incorporating the accumulative power of both systems. Additionally the projectiles propulsion device will actually begin to operate fully from the split second of launch out of the launch tube automatically to enable the fastest and most efficient deployment systems possible. Beneficially the projectile is designed to accept numerous sizes of Co2 supply as therefore to be tailored to the specific requirement the use (big bottle long launch distance or small for a short distance.) 
     The main principal for activation can be described by the following description. Inside the projectile body are all of the necessary components for operation and activation of the propulsion system. The activation system is a critical component of successful operation of the projectiles capability to function correctly. In this embodiment, one piston is supplied to the forward end of the inside of the projectile and supported positioned between two springs front and back (forward and aft). The piston is held in position by the springs which ensure the piston is partially inserted into a barrel like chamber. At the front of the piston is situated a specially designed pin to enable the puncturing of the Co2 (for example) cylinder. On the launch of the projectile out of the launch tube (under barometric air or other gaseous pressure) air is naturally forced into a hollowed out tube running all of the way up the centre of the projectile neck and onto the rear of the piston. The result of this is to force the piston (with the protruding pin) into the opposing neck of the cylinder. The pin is then fully inserted into the neck of the pressurised cylinder and remains in this position (due to the pressure still remaining in the connected launcher and projectile.) When the projectile exits the launch tube (and has all of the kinetic energy available to it from the launcher) the pressure in the projectile body then drops instantly allowing the piston and pin to retract. Once this occurs the pressurised gas contained it the cylinder is allowed out at extreme speeds into the initial chamber (where the piston is located) the piston (supported by the two springs) then is pushed back out of engagement with the barrel section of the striking channel and into the next size chamber (which is bigger as to allow the gas to flow around the piston) and down into the tube indicated inside the neck of the projectile. As the gas travels down the tube it meets the vortices (which act to initiate the rolling over of the air providing body to the high speed air pressure) into the expansion chamber at the rear of the projectile body. On entering the expansion chamber (rolling over itself) the gas meets a second series of vortices (which further enhance this effect) before being slightly re compressed and shooting out of the jet section at the rear end. As the gas exits this section of the process, it is at its most efficient velocity and condition as to produce the required amount of thrust to the projectile as to maximise the thrust available from the amount of gas provided. 
     All functioning (moving) components are stowed in the projectile&#39;s forward position and is principally a piston with a pin at its fwd section and with opposing springs (to allow correct positioning into the barrel of the cylinder and to allow the retraction out of the barrel while under pressure of the discharging Co2 cylinder) when the cylinder is empty the spring pushes back the piston into position inside the barrel neck which is then primed automatically for further use again. At the projectiles forward end a helicoiled screw in section designed to accept a standard Co2 supply firmly. After the launch to the projectile, the cylinder naturally acts as a buoyancy device to prevent the projectile from sinking. 
     Other attributes of this application are to include the fact if inflation occurs in mid air as there is then no resistance to the activation of the compressed air propulsion system and the fact that this system will not operate before the projectile has left the launcher makes this the perfect actuation system as well as the safest. 
     Other applications are currently being sought using this new technology to deploy apparatus where previously the apparatus was deemed too heavy. 
     The materials used in the construction of the products can be any materials from metals, plastics, fibreglass and alloys can be used but principally are intended to be of lightweight materials and recovery lines due to the weight of the full ciclinders initially, upon launch. 
     According to the invention there is provided a specially designed projectile with more than sufficient power to drastically improve deployments of all kinds of MOB and other recovery equipment, spill retention systems, vessel immobilising system/s or other products detailed above.
         To help understanding of the invention, a specific embodiment thereof will now be described by way of the example with reference to the accompanying drawings:       

     Automatically Activated 2 nd  Stage Projective Propulsion System 
     The above-described projectile propulsion system is stowed in the hold of any vessel or area on shore or anywhere by water, etc. A situation arises where the units required to be used. Both the launcher and the integral propulsion cylinder are already charged independently or in conjunction with this apparatus. For example in a man overboard scenario there is a requirement to rescue and individual from the water but as the vessel is moving the individual is getting further away from the launch point on the vessel. The rescuer goes to the stern of the ship (in this embodiment) opens the box in which is stowed all of the connected apparatus above which is charged and ready to go. The operator opens the box, removes the projectile, inserts the projectile into the charged launcher, steps behind the launch box (in this example), which, is on the deck of the vessel and fires the projectile toward the individual a long way away in the water. The launcher launches the projectile which exits the launch tube on the launcher and automatically engages the internal or integral jet propulsion system “which provides enough power” to deploy well past or over the head of the MOB and behind him in the water. If this new projectile system was not used the capability of reaching the individual in this scenario would have been impossible. By incorporating the two systems we are effectively doubling the capabilities of the modern day launchers currently on the market. 
     The above description would operate similarly for use in an oil spill in dock or at anchor but the employment of oil, skirt would be used and not just a recovery harness as described in previous applications. The same technology would be used with all applications as well as with launchable vessel immobilisers, grappling hooks or plain mooring lines as well as with other products and other uses yet to be determined.