Launch speed multiplier

An adapter cage is provided for a compressed gas launcher to multiply launch velocity. Kinematics of wheels integral to the adapter cage results in a doubling of the pusher plate velocity as that motion is imparted on a light-weight launch vehicle. The wheels of the adapter cage can press against the launch vehicle and the wheels are pressed against the walls of the launcher for employing friction at the interface of the wheels and the inner surface of the launcher to transfer motion to force out a muzzle cap of the launcher and to enable launch of the launch vehicle.

CROSS REFERENCE TO OTHER PATENT APPLICATIONS

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a gas propelled mechanical launcher.

(2) Description of the Prior Art

There is an ongoing need for the development of high-speed vehicles for a range of applications. As such, launchers are required to accelerate those vehicles from rest to a high velocity. One type of launcher system for the launch of small devices is a gas propelled canister launcher. Canister launchers are well known in the art.

The basic construction of a gas propelled launcher is a tube divided into two sections by a piston, also referred to as a pusher plate. On one side of the pusher plate is the launch vehicle in a launcher volume and on the other side of the pusher plate is a void or breech chamber that can be rapidly filled with compressed air (from a reservoir or gas generator). The expansion of the compressed air is capable of forcing the pusher plate to launch the vehicle out of the launcher.

The rate of gas release into the volume behind the pusher plate is designed to maximize the transfer of energy to the launch vehicle while controlling the acceleration of the launch vehicle. Gas propelled canister launchers are designed for a specific mass vehicle and acceleration profile.

If there is a need to launch a lighter vehicle from the same launcher (at a higher exit velocity), and the original launch vehicle is replaced with a light weight vehicle; the system performance will be poor. The poor performance is because the light weight vehicle will be accelerated rapidly and the flow of gas into the volume behind the pusher plate will be incomplete. Unless the gas supply system is redesigned; the launcher will perform sub-optimally.

A solution to adapt to varying launch vehicles would be to modify an existing launcher system with an adapter assembly or mechanism that increases launch exit velocity while maintaining the pusher plate design acceleration profile and without altering the gas supply dynamics. Provided that the total assembly (the adapter assembly plus the launch vehicle) is lighter than the standard heavier payload; the exit velocity can be increased to take advantage of the available launch energy.

Based on the state of the prior art, an improved apparatus is needed that can be used to modify a gas generator canister launcher so that light weight vehicles can be launched at high velocity from the launcher without requiring the redesign of the gas generator system.

SUMMARY

It is therefore a primary object and general purpose of the present invention to provide an adapter apparatus for launching a stationary launch vehicle or projectile from rest to a prescribed exit velocity.

It is a still further object of the present invention to provide an adapter apparatus for imparting a linear velocity to a launch vehicle or projectile that exceeds the linear velocity of a pusher plate of a launcher.

To attain the objects of the present invention, an adapter assembly for a compressed gas launcher is provided for use with high-speed projectiles or launch vehicles. The inventive adapter assembly allows forces applied to the pusher plate to be transferred to the launch vehicle.

The adapter assembly includes rollers that engage an inner surface of the cylindrical launcher and the outer surface of the launch vehicle. With the adapter assembly, the effective mass of the launch assembly, as experienced by the pusher plate, can remain constant while the exit velocity of a replacement lighter weight vehicle is increased.

The adapter cage of the assembly comprises three or more rails, connected by two circumferential frames, positioned in the annulus between the outer surface of the launch vehicle and the inner diameter of the launch tube. A first circumferential frame connected to an end of each of these rails is in contact with the pusher plate. An array of wheels are attached to the rails, spaced uniformly along the length of each rail, with rotational axes aligned with the circumference of the annular region. The wheels along each rail are linked together with coupling rods.

The launch vehicle would be positioned in the center of the adapter cage. A muzzle closure cap covers the end of the launch tube and is held in place with sheer pins. Seals are also in place to prevent the low of water from outside of the launch tube into the launcher volume.

To launch the launch vehicle, compressed air is released into the breech chamber from a compressed air canister or tank. Forces on the pusher plate are transferred through the adapter cage and onto the muzzle closure cap. Because the adapter cage wheels are in contact with the inner surface of the launch tube; frictional forces cause the wheels to rotate. The wheels are also positioned to be in contact with the outer surface of the launch vehicle. The wheel rotation transfers forces to the launch vehicle and causes the launch vehicle to move longitudinally toward the muzzle closure cap. When the pusher plate moves toward the end of the launch tube, the launch vehicle will reach the end of the adapter assembly which then forces out the muzzle cap. When the movement force exceeds the failure strength of the sheer pins; the pins fail and the pusher plate moves longitudinally. The launch vehicle then exits the launcher and continues under power.

Because the velocity of the outer surface of the wheels is zero at a no-slip condition on the inner surface of the launch tube and the hub velocity of the wheels is equal to the pusher plate and cage velocity; the inner surface of the wheels at the surface of the launch vehicle will be twice the velocity of the pusher plate and cage velocity. Similarly, the net force exerted on the launch vehicle will be one half of the net force exerted by the pusher plate on the adapter cage.

DETAILED DESCRIPTION OF THE INVENTION

Systems and techniques exist for launching a projectile from rest. The present invention fits into this general category of device but employs a novel set and arrangement of components. These components allow the projectile to be accelerated to a higher velocity.

Referring now to the figures,FIG. 1depicts a launcher system10of the present invention viewed along the side of a launch vehicle100. A launch tube12of the launcher system10is divided into two sections. A first section is the breech chamber14which is fed by an air line16connected via a servo valve18to an air supply tank20. A second section is the launch tube volume22. The breech chamber14and the launch tube volume22are separated by a pusher plate24. The pusher plate24includes a seal26around a circumference in which the seal isolates the breech chamber14from the launch tube volume22.

A muzzle closure cap30is fitted into the open end of the launch tube12. A seal32on the muzzle closure cap30isolates the launch tube volume22from the environment200. Multiple shear pins34are distributed around the circumference of the launch tube12between the muzzle closure cap30and the launch tube12. The launch vehicle100can be centered in the launch tube volume22.

In use, an adapter cage assembly70is positioned in the annulus formed between an outer surface of the launch vehicle100and the launch tube18. The adapter cage assembly70comprises motion transfer wheels74with integral bearings76, motion transfer wheel axles78, linkage bars80, linkage bar pins82and an adapter cage90. A first end surface of the adapter cage90rests on the pusher plate24and a second end surface presses against the muzzle closure cap30.

FIG. 2shows details of the adapter cage90. The adapter cage90comprises a first circumferential ring91as the first end surface, multiple longitudinal rails92, and a second circumferential ring94as the second end surface. The first circumferential ring91and the second circumferential ring94lie in planes parallel to each other and are centered on a central axis of the launch vehicle100. The longitudinal rails92include axle mounting holes94.

Returning toFIG. 1, a plurality of the motion transfer wheels74are attached to the longitudinal rails92of the adapter cage90through mounting holes96(shown inFIG. 2) by the motion transfer wheel axles78. The motion transfer wheels78include the integral bearings76.

The linkage bar80connects the transfer wheels74which are attached to a common longitudinal rail92. Each longitudinal rail92has an associated linkage bar80with the linkage bar connecting the motion transfer wheels74by the linkage bar pins82associated with a common longitudinal rail so that the motion transfer wheels attached to the common rail rotate in tandem.

To load the launch vehicle100into the launcher system10, the pusher plate24is first pressed into the muzzle end of the launch tube12as depicted inFIG. 3. The adapter cage assembly70is then positioned for loading as depicted inFIG. 4. The first circumferential ring91of the adapter cage90is positioned in contact with the pusher plate24(the surface facing the launch vehicle volume) such that the first set of motion transfer wheels74contacts the inner surface of the launch tube12.

The width of the adapter cage assembly70(adapter cage90with the motion transfer wheels74attached) is slightly larger than the inner diameter of the launch tube12. The motion transfer wheels74are slightly compressed during the insertion of the adapter cage assembly70into the launch tube12to produce frictional forces between the motion transfer wheels and the inner diameter of the launch tube. To allow this compression, the motion transfer wheels74are manufactured from a compressible material such as polyurethane.

As depicted inFIG. 5, the launch vehicle100is loaded into the adapter cage assembly70by feeding the launch vehicle axially (launch vehicle tail102first) into the center of the adapter cage assembly70between the motion transfer wheels74. The total width of the space inside of the adapter cage assembly70, between the motion transfer wheels74, is slightly smaller than the outer diameter of the launch vehicle100.

As the launch vehicle100is pressed into the adapter cage assembly70; the launch vehicle engages the motion transfer wheels74. When the launch vehicle100engages the motion transfer wheels74; the motion transfer wheels are slightly compressed to produce large frictional forces between the motion transfer wheels and the outer diameter of the launch vehicle.

As depicted inFIG. 6, as the launch vehicle100is inserted further into the adapter cage assembly70, the adapter cage assembly and pusher plate24are forced into the launch tube12toward the breech chamber14through the action of the linked motion transfer wheels74and their engagement with the launch tube.

When the launch vehicle100and adapter cage assembly70are fully retracted into the launch tube12, as depicted inFIG. 7, the muzzle closure cap30is pressed into the open end of the launch tube and the shear pins34are inserted through the launch tube to secure the muzzle closure cap in place.

The launch process is initiated by opening the servo valve18to allow compressed air to flow through the air line16from the air supply tank20into the breech chamber14. As pressure rises in the breech chamber14; force is transferred through the pusher plate24and the adapter cage90to the muzzle closure cap30. When the force exceeds the failure strength of the shear pins34and the shear pins fail; the pusher plate24and adapter cage90then force the muzzle closure cap30off the end of the launch tube12.

Further expansion of gasses in the breech chamber14force the pusher plate24and adapter cage assembly70along the axis of the launch tube12, as depicted inFIG. 6. The motion transfer wheels74are in contact with the inner surface of the launch tube12during the launch process.

Frictional forces create a no slip condition at the contact point between the motion transfer wheels74and the inner surface of the launch tube12. As the adapter cage assembly70is forced longitudinally along with the central axis of the motion transfer wheels74; the motion transfer wheels and the outer surface of the launch vehicle12are forced longitudinally at twice the rate as the adapter cage assembly70. The launch vehicle12motion continues longitudinally until the launch vehicle is no longer in contact with the motion transfer wheels74at which time the launch vehicle continues under power.