Abstract:
A parachute release mechanism is provided which is compact, lightweight, and free from external wire harnesses. The release mechanism includes a passage connected between a source of pressurized gas and a piston chamber having a piston disposed therein. A shear pin is disposed in an opening in the piston and in the piston chamber. Activation of the source of pressurized gas causes the piston to move forward shearing the shear pin and either deploying or releasing a parachute.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a parachute release mechanism, and more particularly, to a multi-stage parachute release mechanism. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Parachutes are used in many applications including the deployment of cargo to remote locations by air drop. In addition, when a weapon, such as a torpedo, is launched from an aircraft at high speeds, random forces will cause early pitch acceleration and random torpedo flight attitudes. To counteract these erratic movements, early torpedo stabilization is needed. Similarly, when an intermediate water depth mine is launched from an aircraft at high speeds, the impact of the water depth mine with the water surface can destroy the mine. Thus, stabilization and deceleration of the mine is also needed. Many parachute systems include a first parachute which is deployed to provide early stabilization and a second main parachute which is deployed in order to further stabilize or decelerate the object being dropped. The deployment of the first parachute and the main parachute without the use of an external electrical wire harness is desirable when used with underwater torpedoes or mines. 
     Accordingly, the present invention provides a parachute release mechanism comprising: a gas cartridge; a passage connected between said gas cartridge and a piston chamber having a piston member disposed therein; a shear pin disposed in an opening in said piston member and in an opening in said piston chamber; wherein activation of said gas cartridge applies a pressure against said piston which causes said shear pin to be sheared and said shear pin to be released which thereby deploys a parachute. The present invention also employs a load carrying segment disposed adjacent to a piston for securing a fitting member in place. The movement of the piston allows the load carrying segment to disengage the fitting member which is thereby released. 
     The release mechanism of the present invention may also find utility in other areas where a light weight compact release mechanism is desired. Accordingly, a release mechanism is provided, comprising: a source of pressurized gas; a passage connected between said source and a piston chamber having a piston member disposed therein; at least one load carrying segment held in place by said piston member; said at least one load-carrying segment having load carrying portions for securing a first member to a second member; wherein activation of said source of pressurized gas applies a pressure against said piston which causes said piston to be moved away from said at least one load carrying segment, thereby allowing said load carrying segment to disengage said first and second members. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIGS. 1-5 illustrate side views of an intermediate water depth mine in various stages of deployment of a parachute system subsequent to drop from the bombay of an aircraft; and 
     FIG. 6 is a cross-sectional view of the multi-stage parachute release mechanism according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1-6, the present invention will be described. FIGS. 1-5 illustrate the various stages of deployment of a parachute system 10 subsequent to drop of an intermediate water depth mine 12 according to the principles of the present invention. The parachute system 10 includes a small stabilizer parachute 14 which is shown deployed in FIG. 2. As shown in FIG. 2, the lines 14a of the stabilizer parachute are connected to an attachment fitting 16 which is also connected to deployment lines 18 attached to main parachute 20. The main parachute 20 is shown deployed in FIG. 3, and located aft thereof are deployment lines 18. Connected to the deployment lines 18 and the stabilizer parachute 14 is the attachment fitting 16. The deployment lines 18 break free from the main parachute as shown in FIG. 4 after the attachment fitting 16 is released and main parachute 20 is deployed. Main parachute 20 is attached to main parachute attachment fitting 24 by lines 22. Main parachute 20 and attachment fitting 24 are released from intermediate water depth mine 12 at approximately the time the mine 12 enters the water, as shown in FIG. 5. 
     With reference to FIG. 6, the release mechanism of the present invention will be described. As mentioned above, the release mechanism 30 of the parachute system 10 is attached to the aft end of a vehicle 12 such as an intermediate water depth mine or a torpedo. Release mechanism 30 includes an adapter plate 32 mounted on the interior 34 of vehicle 12 by a plurality of bolts 36. A manifold 38 is attached to adapter plate 32. Manifold 38 includes first, second, and third gas cartridge ports 40, 42, 44, respectively. First gas cartridge port 40 communicates with a passage 46 provided in an inner-manifold tube 48. Passage 46 is connected to a first piston chamber 50 disposed in a deployment piston housing 52. A first piston 54 is disposed in first piston chamber 50. Canister cover 13 is attached to first piston 54 by a bolt 56. A shear pin 58 is disposed in a bore 60 in first piston 54 and also in hole 62 disposed in deployment piston housing 52. Deployment piston housing 52 is provided with internal threads 52a which engage external threads 16a of attachment fitting 16. 
     Second gas cartridge port 42 communicates with passage 64 defined by the grooved outer diameter of inner-manifold tube 48 and an inner surface of outer manifold tube 66. Passage 64 communicates with first release piston chamber 68 defined by attachment fitting 16. A first release piston 70 is disposed in first release piston chamber 68. A plurality of load carrying segments 72 are provided with load carrying portions 74, 76 which secure attachment fitting 16 to a load link member 78. Attachment fitting 16 is provided with a radially inward projecting portion 80 which engages load carrying portion 74, while load link 78 is provided with a radially inward projecting portion 82 which is engaged by load carrying portion 76 of segments of 72. A jam nut 84 is threadedly attached to load link 78 and applies a force against attachment fitting 16 thereby applying a pre-load to load carrying segments 72. Release piston 70 is provided adjacent to load carrying segments 72 for supporting segments 72 in a radially inward direction. A shear pin 84 is provided in a bore 86 in first release piston 70 and also in a hole 88 disposed in attachment fitting 16. 
     Load link member 78 is provided with an externally threaded portion 78a which is threadedly attached to internally threaded portion 90a of a main parachute support column 90. Main parachute attachment fitting 24 is provided with an internally threaded portion 24a which is threadedly attached to an externally threaded portion 90b of main parachute support column 90. Gas cartridge port 44 is connected to a passage 92 which communicates with a second release piston chamber 94. A second release piston 96 is disposed in second release piston chamber 94. A shear pin 98 is disposed in a bore 100 in second release piston 96 and in a hole 102 in main parachute support column 90. A plurality of load carrying segments 104 are disposed between second release piston 96 and a radially inward extending portion 106 of main parachute support column 90 and a radially inward extending portion 108 of adapter plate 30. A torque resisting pin 110 is shown received in an end portion 112 of support column 90 and a corresponding bore 114 in adapter plate 32. 
     A plurality of gas cartridges 116 are attached to first, second, and third gas cartridge ports 40, 42, 44. In operation, gas cartridge 116 attached to first gas cartridge port 40 is activated to deploy stabilizer parachute 14 by the action of hot gases emanating from the cartridge 116 installed into port 40. The gases flow up the center of passage 46 in tube 48 and build up behind piston 54 until enough pressure is obtained to cause the piston 54 to shear shear pin 58 and deploy canister cover 13 to which the first stage parachute 14 is attached. The piston 54, bolt 56, and canister 13 are ejected, but everything else remains intact at this time. 
     The first stage parachute loads are transferred to attachment fitting 16 and to load carrying segments 72, load link 78, support column 90, adapter plate 32, and into the vehicle structure 12. 
     The main parachute 20 is released by hot gases emanating from an electro-explosive cartridge 116 installed in second gas cartridge port 42. The gases travel from the cartridge into the grooved outer diameter slots 64 of inner-manifold tube 48 and to release piston chamber 68 behind first release piston 70. The gas pressure builds up behind first release piston 70 forcing it to shear shear pin 84. First release piston 70 moves forward allowing load carrying segments 72 to fall toward the centerline of the device thus releasing the structural attachment of attachment fitting 16 to the main vehicle 12. The load on attachment fitting 16 produced by the first stage parachute 14 plus the internal gas pressure behind piston 70 forces the attachment fitting 16 and deployment piston housing 52 away from the vehicle 12. 
     The main parachute deployment lines 18 are also attached to the attachment fitting 16. The first stage parachute 14 drags out the attachment fitting 16 and along with it, the main parachute bag 18a, as shown in FIG. 3. The main parachute suspension lines 22 are supported by main parachute attachment fitting 24. Release of the main parachute 20 can be accomplished underwater or just prior to impact with the surface of the water. 
     The main parachute 20 is released by hot gases emanating from an electro-explosive cartridge 116 installed in third gas cartridge port 44. The gas pressure builds up in second release piston chamber 94 behind second release piston 96 causing it to shear shear pin 98 and move forward. The forward motion of second release piston 96 removes the restraint on the load carrying segments 104 and allows them to fall toward the center of the device thus releasing the structural attachment of the main parachute support column 90 to vehicle 12. The load on the main parachute 20 assists in moving the segments 104 toward the center by providing a camming action between the support column 90 and the load carrying segments 104. The load on the main parachute attachment fitting 24 produced by the dragging main parachute 20 and the gas pressure behind piston 96 forcibly eject the main parachute attachment fitting 24 and jam nut 84, load link 78, inner-manifold tube 48, outer-manifold tube 66, second release piston 96 and load carrying segments 104 leaving manifold 38 and adapter plate 23 along with the electro-explosive cartridges 116 installed in ports 40, 42, and 44 with the vehicle 12. This action releases the main parachute 20 from the vehicle and leaves only a cavity in the vehicle 12 and no external protrusions. 
     The release device 30 can be safely transported and handled by threading a long safety rod into the threaded hole 118 and manifold 38. 
     Variations of the design of the present invention can be used in any application that requires high load carrying capability with the ability of quick release. An electrical signal to the electro-explosive device is all that is required for release. In addition, the present invention can be used for the release of other parachute systems, vehicle stages, tension cables, and many other devices. A variation to the use of electro-explosive devices would be use of stored high pressure gases to initiate the release sequence. 
     The coaxial arrangement of pistons 54, 70, and 96 provides a compact arrangement which allows the release mechanism 30 to be produced with reduced weight and spacial constraints. The use of individual load carrying segments supported by a movable piston which releases the load carrying segments provides a unique method for releasing members which allow the electrical wire into the maintained interior of the vehicle while releasing the members from the exterior of the vehicle. 
     Furthermore, the porting of the gases along the centerline of the device provides an efficient use of the space and thus contributes to the compactness of the design. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.