Abstract:
An apparatus that provides shock absorption and ejection for a payload that is to be deployed from a launch capsule is disclosed. The payload ejection mechanism comprises a movable housing that houses a resilient member and a shock-damping system. The rapid acceleration of the capsule upon launch causes the movable housing to move, which compresses the resilient member, thereby storing energy. Movement of the housing also provides shock damping behavior. A locking mechanism maintains the compression of the resilient member until the capsule opens to deploy the payload. As the capsule opens, a restraint decouples from the locking mechanism and permits the resilient member to expand. Expansion of the resilient member causes the movable housing to move, thereby propelling the payload away from the capsule.

Description:
FIELD OF THE INVENTION 
   The present invention relates to munitions or launch capsules and, more particularly, a payload ejection mechanism for use in conjunction with such capsules. 
   BACKGROUND OF THE INVENTION 
   Some launch capsules carry payloads that are intended to be separated from the capsule in flight. This familiar process of deploying munitions or the like from a capsule is depicted in  FIGS. 1A through 1C . 
     FIG. 1A  depicts the launch of capsule  100 . In this illustration, capsule  100  contains booster  108 , which provides the thrust required for launch. In this example, the payload is an unmanned aerial vehicle, usually referred to as a “UAV.” The UAV is not visible in  FIG. 1A  since it is within shell  102   
   At some predetermined altitude or time, shell  102  of capsule  100  opens in preparation for releasing UAV  110 , as depicted in  FIG. 1B . Typically, explosive bolts or similar mechanisms are used to open the capsule. As the capsule opens, UAV  110  is released from launch restraints so that it is free to separate from the capsule. The release mechanism can be, for example, explosive bolts or the like. 
   Aerodynamic forces assist with the continued opening of capsule  100  and deployment of UAV  110 . More particularly, once capsule  100  partially opens, air resistance forces segments  104  and  106  of shell  102  further apart. The force of the air against segments  104  and  106  also slows capsule  100 . Since UAV  110  has been released from its restraints so that it&#39;s no longer coupled to the capsule, its forward motion is not retarded at the same rate as capsule  100 . As a consequence, UAV  110  separates from the capsule, as depicted in  FIG. 1C . 
   There are several important considerations regarding capsule-deployed payloads. One consideration is that the payload must be able to withstand the axial shock of the capsule&#39;s launch. To that end, the launch capsule typically incorporates a shock isolation system that substantially isolates the payload from axially-aligned shock (e.g., due to the high rate of acceleration that is required for launch). 
   A second consideration relates to the specifics of payload deployment. For some applications, the success of the deployment operation will depend upon how quickly the payload separates from the capsule. In this regard, one concern relates to the presence of debris, which is often produced when the capsule opens. This debris can damage the payload. A second concern applies to payloads that deploy wings to sustain flight. If the payload doesn&#39;t rapidly clear the capsule, the wings can be damaged during deployment. 
   Payload separation can be particularly problematic during low-speed deployments, wherein relatively diminished aerodynamic forces are available to brake the capsule. In such cases, the payload and capsule might not separate enough to permit safe wing deployment or for the payload to clear debris, etc. 
   There is a need, therefore, for a way to reduce the risks to payloads that are deployed from launch capsules. 
   SUMMARY OF THE INVENTION 
   The present invention provides a combined shock absorption and payload ejection mechanism that reduces the risks to capsule-deployed payloads. 
   In accordance with the illustrative embodiment of the invention, the combined mechanism is disposed within a launch capsule. The mechanism is capable of reducing the shock that a payload would otherwise be exposed to upon launch and is also capable of increasing the separation distance between the payload and capsule upon deployment faster than in the prior art. 
   In the illustrative embodiment, the payload ejection mechanism comprises a movable housing that houses an energy-storing element. In the illustrative embodiment, the energy-storing element is a resilient member, such as a coil spring. A damping system that includes a piston and cylinder is also at least partially housed within the movable housing. 
   The payload is disposed on the movable housing. Due to the rapid acceleration of the capsule upon launch, the movable housing moves “downward.” Since both the resilient member and the piston are operably coupled to the housing, the downward movement of the movable housing compresses the resilient member and results in further insertion of the piston into the cylinder. The former action stores energy (as potential energy in the compressed spring) and the latter action results in damping that provides shock isolation for the payload. 
   A locking mechanism maintains the compression of the resilient member until the capsule opens to deploy the payload. As the capsule opens, a restraint decouples from the locking mechanism and permits the resilient member to expand. Expansion of the resilient member causes the movable housing to move. Since the payload is disposed on the movable housing, it is propelled forward, such that the separation distance between the payload and the capsule increases more quickly than in the absence of payload ejection mechanism. 
   The illustrative embodiment of the invention is an apparatus comprising:
         a damping system;   an energy-storing element, wherein energy is stored within the energy-storing via compression of a resilient member; wherein:
           (1) in response to a first force, the damping system provides damping action and the energy-storing element stores energy; and   (2) the damping system and the energy-storing element are configured so that, in response to the first force, the damping action and the storing of energy occurs substantially simultaneously; and   
           a locking mechanism for maintaining compression of the resilient member.       

   A method in accordance with the illustrative embodiment of the invention comprises:
         compressing a resilient member in response to an accelerating force that accelerates a capsule;   advancing a piston into a cylinder in response to the accelerating force, wherein the compressing and advancing occur substantially simultaneously;   maintaining compression of the resilient member until a shell of the capsule opens;   opening the shell, thereby releasing the compression of the spring.       

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1A through 1C  depict the deployment of a payload from a capsule, in accordance with the prior art. 
       FIGS. 2A through 2C  depict the deployment of a payload from a capsule, wherein the capsule contains a payload-ejection mechanism in accordance with the illustrative embodiment of the present invention. 
       FIG. 3  depicts details of a payload ejection mechanism in accordance with the illustrative embodiment of the invention. 
       FIG. 4  depicts the payload ejection mechanism after an energy-storing element has absorbed energy during launch of a capsule that contains the payload ejection mechanism and a payload. 
       FIG. 5  depicts the payload ejection mechanism after release of the energy that is stored in the energy-storing element. 
   

   DETAILED DESCRIPTION 
   The following terms are defined for use in this specification, including the appended claims:
         Operatively-coupled means that the operation, action, movement, etc. of one object affects another object. For example, consider a spring that abuts a plate.       

   When the plate is moved, downward, the spring is compressed. The plate and the spring are considered to be “operatively-coupled.” Operatively-coupled devices can be coupled through any medium (e.g., semiconductor, air, vacuum, water, copper, optical fiber, etc.) and involve any type of force. Consequently, operatively-coupled objects can be electrically-coupled, hydraulically-coupled, magnetically-coupled, mechanically-coupled, optically-coupled, pneumatically-coupled, physically-coupled, thermally-coupled, etc.
         Resilient and its inflected forms, refers to a tendency to return to a reference or original state (e.g., shape, position, etc.). Resilience, as a characteristic of a member, can arise in several ways. In some cases, resilience arises from a particular structural configuration (e.g., a coil spring, a cantilever, etc.). In some other cases, the resilience of a member arises due to the nature of the material(s) that form the member (e.g., rubber, etc.). The term “resilient,” as used herein, is intended to encompass resilience that arises in any manner.       

     FIG. 2A  depicts the launch of capsule  200 , wherein the capsule contains payload-ejection mechanism  208  (see, e.g.,  FIGS. 2B and 2C ) in accordance with the illustrative embodiment of the present invention. The capsule can be launched via a “hot launch” technique, such as by using a booster. Alternatively, capsule  200  can be launched via various “cold launch” techniques, including pressurized gas, electromagnetics, and the like. The manner in which capsule  200  is not germane to an understanding of the invention and those skilled in the art will be able to design and implement a suitable launch system for launching capsule  200 . 
   As described further in conjunction with  FIGS. 3 and 4 , payload-ejection mechanism  208  within capsule  200  includes an energy-storing element. The energy-storing element stores some of the energy of launch. In the illustrative embodiment, energy is stored by compressing a resilient member. 
   At some predetermined altitude or time after launch, capsule  200  opens in preparation for deploying payload  210 , as depicted in  FIG. 2B . Shell  202  of capsule  200  is adapted to separate into two or more segments  204  and  206  to enable deployment. Explosive bolts or other such devices are used to open shell  202  in known fashion. 
   In accordance with the illustrative embodiment, while shell  202  remains closed, the energy-storing element is restrained from releasing its energy. The opening of shell  202  releases a locking mechanism, which, in turn, enables the compressed resilient member to return to its uncompressed state. As it does so, the launch energy stored in the resilient member is converted to kinetic energy; that is, the movement of the resilient member. 
   Payload  210  is operably coupled to the resilient member and, as a consequence, some of the kinetic energy of the re-expanding resilient member is imparted to payload  210 . The payload is propelled away from open shell  202 , as depicted in  FIG. 2C , as a result of this energy transfer. 
     FIG. 3  depicts detail of payload-ejection mechanism  208  within capsule  200 .  FIG. 3  depicts the payload-ejection mechanism in a pre-launch state. The portion of capsule  200  that is depicted in  FIG. 3  shows capsule housing  340  and the lower portion of shell segments  204  and  206 . As depicted in  FIG. 3 , shell segments  204  and  206  are pivotably coupled to capsule housing  350  at hinges  354  and  356 . Payload  210  is not depicted for the sake of clarity. 
   Payload-ejection mechanism  208 , which is disposed within and extending from capsule housing  350 , includes movable housing  312 , housing restraint  320 , energy-storing element  322 , locking mechanism  324 , lock restraint  334 , and damping system  336 , interrelated as shown. 
   Movable housing  312  is a cylindrical wall that terminates, at its upper end, in platform  314 . Coupling  316  is disposed on top of platform  314  for engaging a complementary coupling (not depicted) that depends from payload  210 . These couplings enable the payload to be positively restrained for pre-launch activities (e.g., transportation, etc.). At launch, or as the shell opens, the coupling is released so that payload  210  is able to separate from capsule  200 . The couplings can be decoupled via explosive bolts or other mechanisms. 
   Energy-storing element  322  comprises a resilient member. In the illustrative embodiment, the resilient member is a coil spring. In some further embodiments, the resilient member comprises a resilient material (e.g., rubber, etc.), but is not in the form of a coil spring. 
   Energy-storing element  322  is disposed beneath movable housing  312 . In the illustrative embodiment, the upper end of energy-storing element  322  abuts the lower surface of platform  314 . The lower end of energy-storing element  322  contacts base  352  of capsule housing  350 . 
   In the illustrative embodiment, locking mechanism  324  is implemented as a “collar” or toroid that encircles a portion of movable housing  312 . The locking mechanism is seated on the upper edge of capsule housing  350 . The collar comprises inner circular wedge  326 , outer circular wedge  330 , and resilient layer  328 , the latter sandwiched between the inner and outer circular wedges. Inner circular wedge  326  abuts the surface of movable housing  312 . 
   Locking mechanism is a “one-way” mechanism such that, when engaged as in  FIG. 3 , it permits movement of movable housing  312  in only one direction. In particular, locking mechanism  324  permits movable housing  312  to move “downward,” when urged, into capsule housing  350 . The engaged locking mechanism will not, however, permit movement of movable housing  312  “upward,” out of capsule housing  350 . 
   In some embodiments, this one-way behavior is provided by providing ridges and grooves (not depicted) on facing surfaces of locking mechanism  324  and movable housing  312 . The ridges and grooves on the inner surface of inner circular wedge  326  are angled downward toward base  352  of capsule housing  350 . The ridges and grooves on the outer surface of movable housing  312  are angled upward. As a consequence, and with the application of sufficient force, the upward-facing ridges on the outer surface of movable housing  312  will “slide” over the downward facing ridges on the inner surface of inner circular wedge  326 . Resilient layer  328  between the two wedges facilitates sufficient “play” at the interface of the wedge  326  and movable housing  312  to enable this movement. As a ridge on the outer surface of movable housing  312  slides over a ridge on the facing surface of inner circular wedge  326 , it seats in a downward-facing groove (on the inner surface of inner circular wedge  326 ). Consequently, movement in the reverse direction is prevented. 
   As described later in conjunction with  FIG. 4 , in the absence of some form of restraint for locking mechanism  324 , energy-storing element would not be able to store energy. To this end, lock restraint  334  is provided. The lock restraint, when engaged, prevents locking mechanism from moving upward. 
   In the illustrative embodiment, lock restraint  334  is implemented as inward-extending ridge on the inner surface of shell segments  204  and  206 . When the shell segments are closed, the ridge overlies locking mechanism  324  such that it is prevented from moving upward. 
   Housing restraint  320  is disposed on inner wedge  326  of locking mechanism  324 . When engaged, housing restraint  320  restrains movable housing  312  from moving. Typically, housing restraint  320  is engaged for pre-launch activities. When launch of capsule  200  is imminent, housing restraint is released. As discussed in conjunction with  FIG. 4 , release of housing restraint  320  enables damping system  336  and energy-storing element to function. Housing restraint  320  can be released by firing explosive bolts, etc. 
   Damping system  336  is disposed beneath and operably engaged to movable housing  312 . In the illustrative embodiment, damping system  336  comprises piston  338  and cylinder  340 . 
   The upper end of piston  338  abuts the lower surface of platform  314  of movable housing  312 . The lower circular portion of piston  338  extends into underlying cylinder  340 . The cylinder is disposed on base  352  of capsule housing  350 . 
   In the illustrative embodiment, locking mechanism  324 , movable housing  312 , energy-storing element  322 , piston  338 , and cylinder  340  are co-axial with respect to one another. 
   As previously noted,  FIG. 3  depicts payload-ejection mechanism  208  in a pre-launch state. On the other hand,  FIG. 4  depicts payload-ejection mechanism  208  directly after launch and before shell segments  204  and  206  have opened. Although it is not shown for the sake of clarity, payload  210  is understood to be resting on platform  314 . 
   During launch, capsule  200  is accelerated upward rapidly. The presence of payload  210  on platform  314  forces the movable housing  312  downward. This forces piston  338  into cylinder  340 , which provides shock absorption for payload  210 . At the same time that the piston is driven into the cylinder, energy-storing element  322  is compressed. Locking mechanism  324  maintains the compression of energy-storing element  322  until shell segments  204  and  206  separate. 
     FIG. 5  depicts payload-ejection mechanism  208  after shell segments  204  and  206  separate. As depicted in  FIG. 5 , the capsule opens as shell segment  204  pivots about hinge  354  and shell segment  206  pivots about hinge  356 . As this occurs, lock restraint (ridge)  334  loses contact with locking mechanism  324 . Once this occurs, energy-storing element  322  is free to return to its uncompressed state, which it does. As this occurs, payload  210  is propelled forward, or capsule  200  is propelled backward (i.e., slowed), as a function of the relative masses of the payload and the capsule. In either case, the separation distance between payload  210  and capsule  200  is increased. 
   As previously indicated, piston  338  is operably engaged to platform  314  in the sense that when the platform moves downward, the piston is likewise forced downward. In the illustrative embodiment, piston  338  is not affixed to platform  314 , so that when energy-storing element  322  expands, piston  338  does not travel with platform  314 . If piston  338  and platform  314  were affixed to one another, the piston would withdraw from the cylinder when energy-storing element  322  expands. The latter scenario is disadvantageous since this would reduce the velocity of expanding energy-storing element, thereby providing a reduced impulse to payload  210  (or capsule  200 ). 
     FIG. 6  depicts method  600  in accordance with the illustrative embodiment. As depicted in  FIG. 6 , method  600  includes the operations of:
           602 : compressing the resilient member in response to an accelerating force that accelerates the capsule;     604 : advancing the piston into the cylinder in response to the accelerating force, wherein the compressing and advancing operations occur substantially simultaneously;     606 : maintaining compression of the resilient member until the shell of the capsule opens;     608 : opening the shell, wherein opening the shell causes the release of compression of the resilient member.       
   It is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. For example, in this Specification, numerous specific details are provided in order to provide a thorough description and understanding of the illustrative embodiments of the present invention. Those skilled in the art will recognize, however, that the invention can be practiced without one or more of those details, or with other methods, materials, components, etc. 
   Furthermore, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the illustrative embodiments. It is understood that the various embodiments shown in the Figures are illustrative, and are not necessarily drawn to scale. Reference throughout the specification to “one embodiment” or “an embodiment” or “some embodiments” means that a particular feature, structure, material, or characteristic described in connection with the embodiment(s) is included in at least one embodiment of the present invention, but not necessarily all embodiments. Consequently, the appearances of the phrase “in one embodiment,” “in an embodiment,” or “in some embodiments” in various places throughout the Specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments. It is therefore intended that such variations be included within the scope of the following claims and their equivalents.