Abstract
A separation device assembly with efficiency that allows for multi-fault-tolerance. The separation device assembly comprising an inflation device that applies force to a shear plate assembly which in turn applies focused force to a frangible portion. The assembly further comprising a means for limiting excess movement after fracture so that residual energy from the inflation device is applied to non-fractured portions of the assembly.
Claims
1. A separation device assembly comprising: A separation device having at least two attachment portions, at least one frangible portion, and at least one movement stopping element; the attachment portions being arranged to fixedly connect to at least two separate structural components, with the attachment portions being joined to each other through at least one frangible portion, with at least one movement stopping element positioned as to confine the post-fracture movements of at least one frangible portion to between one tenth to sixty times the elongation limit of the fracture plane material; wherein an expansion cavity is formed between at least one attachment portion and at least one frangible portion; further comprising, at least one inflation device located within the expansion cavity.
2. The separation device assembly of claim 1, wherein the frangible portion or portions contain a groove or stress riser to facilitate fracturing.
3. The separation device assembly of claim 1, wherein an inflation device is configured to apply force against the frangible portions of the separation assembly.
4. The separation device assembly of claim 1, wherein at least one inflation device is inflated by at least one gas producing combustible load.
5. The separation device assembly of claim 1, further comprising a shear plate assembly which transfers and focuses force from the inflation device at or near the fracture plane of at least one frangible portion.
6. The separation device assembly of claim 5, wherein the shear plate assembly is integrally formed with at least one other shear plate assembly.
7. The separation device assembly of claim 6, wherein the shear plate assemblies have a thinner region between them that facilitates relative bending of the shear plate assemblies.
8. The separation device assembly of claim 5, wherein the shear plate assembly is affixed to at least one other shear plate assembly by means of a hinge.
9. The separation device assembly of claim 5, wherein the shear plate assembly is affixed to at least one other shear plate assembly by at least one fastener.
10. The separation device assembly of claim 5, wherein the shear plate assembly is bonded to at least one other shear plate assembly.
11. The separation device assembly of claim 5, wherein the shear plate assembly has a point shaped tip.
12. The separation device assembly of claim 5, wherein the shear plate assembly has a blunt shaped tip.
13. The separation device assembly of claim 5, wherein the shear plate assembly has a flared shaped tip.
14. The separation device assembly of claim 5, wherein the shear plate assembly is bonded to at least one frangible portion.
15. The separation device assembly of claim 5, wherein the shear plate assembly is affixed to at least one frangible portion with a least one fastener.
16. The separation device assembly of claim 5, wherein the shear plate assembly is integrally formed with at least one frangible portion.
17. The separation device assembly of claim 5, wherein the shear plate assembly is bonded to at least one inflation device.
18. The separation device assembly of claim 5, wherein the shear plate assembly is affixed to at least one inflation device with a least one fastener.
19. The separation device assembly of claim 5, wherein the shear plate assembly is integrally formed with at least one inflation device.
20. The separation device assembly of claim 4, wherein an inflation device is configured to apply force against at least one shear plate assembly.
21. The separation device assembly of claim 20, wherein the inflation device is configured with a recurved groove along its axis.
22. The separation device assembly of claim 1, wherein at least one movement stopping element is affixed to at least one attachment portion with at least one fastener.
23. The separation device assembly of claim 1, wherein at least one movement stopping element is bonded to at least one attachment portion.
24. The separation device assembly of claim 1, wherein at least one movement stopping element is integrally formed with at least one attachment portion.
25. The separation device assembly of claim 1, wherein at least one movement stopping element is integrally formed with at least one attachment portion and integrally formed with at least one frangible portion.
26. The separation device assembly of claim 1, wherein at least one movement stopping element is fastened to at least one frangible portion with at least one fastener.
27. The separation device assembly of claim 1, wherein at least one movement stopping element is bonded to at least one frangible portion.
28. The separation device assembly of claim 1, wherein at least one movement stopping element is integrally formed with at least one frangible portion.
29. The separation device assembly of claim 1, wherein at least one frangible portion is fastened to at least one attachment portion with at least one fastener.
30. The separation device assembly of claim 1, wherein at least one frangible portion is bonded to at least one attachment portion.
31. The separation device assembly of claim 1, wherein at least one frangible portion is integrally formed with at least one attachment portion.
32. The separation device assembly of claim 1, wherein additional compressive load bearing elements are used as the stopping means which confines post fracture movement to between one tenth to sixty times the elongation limit of the fracture plane material.
33. A method of separating portions of a structure at all locations along a three dimensional separation assembly, the method comprising: an inflation device deposited inside an expansion cavity used to fracture frangible portions, and wherein the energy for inflation is limited, and also providing a stopping means which confines post fracture movements of any frangible portions to between one tenth to sixty times the elongation limit of the fracture plane material.
34. The method of claim 33, wherein at least one shear plate assembly vectors and focuses inflation device force at or near the desired fracture plane.
35. The method of claim 34, wherein the inflation device is configured with a recurved groove along its axis.
36. The method of claim 34, wherein the inflation device is configured to apply thrusting force between the separated structures after complete fracturing of all frangible portions has occurred.
37. The method of claim 33, wherein the energy delivery profile to the inflation device is matched to the design requirements of the separation assembly.
38. The method of claim 33, further comprising a means of sensing the complete fracturing of all frangible portions of the assembly in order to control the energy delivery profile of the inflation device through staged firing of combustible loads.
39. The method of claim 33, wherein additional compressive load bearing elements are used as the stopping means which confines post fracture movement to between one tenth to sixty times the elongation limit of the fracture plane material.
40. A separation device assembly comprising: A separation device having at least two attachment portions, and at least one frangible portion, with attachment portions being arranged to fixedly connect to at least two separate structural components, with the attachment portions being joined to each other through at least one frangible portion, wherein an expansion cavity is formed between at least one attachment portion and at least one frangible portion; further comprising, at least one inflation device located within the expansion cavity which is configured to apply force to at least one shear plate assembly, also comprising, at least one shear plate assembly located within the expansion cavity which is configured to vector force from the inflation device and apply focused force at or near the fracture plane of at least one frangible portion.
Description
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0048] The various embodiments of the present invention, as well as representations of prior art can be understood with reference to the following drawings. The components are not necessarily to scale. Also, in the drawings, like reference numerals designate corresponding parts throughout the several views:
[0049] FIG. 1 is a reliability diagram of prior art;
[0050] FIG. 2A is a partial cross-sectional view of an example prior art frangible joint assembly before the frangible joint had been activated;
[0051] FIG. 2B is a view similar to that of FIG. 2A where the frangible joint has been explosively activated and shows prior art assumption of symmetric functionality;
[0052] FIG. 2C is a view similar to that of FIG. 2A where the frangible joint has been explosively activated and the XTA is beginning to inflate and is applying force to both of the legs;
[0053] FIG. 2D is a view similar to that of FIG. 2C where a ligament has fractured on the right side and the XTA has begun to inflate more easily toward the right side;
[0054] FIG. 2E is a view similar to that of FIG. 2D where the leg on the right side is bent out even further, and with the energy of the XTA almost exhausted, has allowed the ligament on the left side to remain unbroken;
[0055] FIG. 2F is a partial perspective cross-sectional view of an example prior art frangible joint assembly, showing how an XTA can extrude itself through an already fracture ligament side and therefore waste combustion energy;
[0056] FIG. 3A is a partial cross-sectioned view of one embodiment of the present invention where the attachment portions, frangible portions, and movement stopping elements are all bolted together;
[0057] FIG. 3B is a view similar to that of FIG. 3A where the frangible joint has been activated and pressure within the XTA causes fracturing of one of the ligaments;
[0058] FIG. 3C is a view similar to that of FIG. 3B where ligament fracture has extended to the opposite side of the joint and all ligament fractures in this view are complete;
[0059] FIG. 3D is a view similar to that of FIG. 3C wherein the shear plate assemblies are pushed flat and the stop plates are flexed outward;
[0060] FIG. 3E is a view similar to that of FIG. 3D where XTA rounding continues and has pushed the upper and lower attachment portions away from each other;
[0061] FIG. 3F is a view similar to that of FIG. 3E where XTA rounding has pushed the upper and lower attachment portions apart to the point where no contact between the two attachment portions exists;
[0062] FIG. 4 is a diagram that plots force against the shear plate assemblies as a function of time, which shows the preferred sequence of ligament fracturing and push off events;
[0063] FIG. 5 is a reliability diagram of the present invention;
[0064] FIG. 6 is a partial cross-sectioned view of one embodiment of the present invention where one attachment portion, all frangible portions, and all movement stopping elements are all integral to one another, and utilizes the typical XTA configuration employed by prior art;
[0065] FIG. 7 is a partial cross-sectioned view of one embodiment of the present invention where the upper attachment portion and a single ligament design creates the expansion cavity, wherein the XTA is placed, and having a movement stopping element that is integral to the upper attachment portion;
[0066] FIG. 8 is a partial cross-sectioned view of one embodiment of the present invention where one attachment portion, all frangible portions, and all movement stopping elements are integral to one another, and utilizes the XTA configuration of the present invention, shearing mechanism, and multiple combustible load redundancy;
[0067] FIG. 9 is a partial cross-sectioned view of one embodiment of the present invention where one attachment portion, all frangible portions, and all movement stopping elements are integral to one another, and utilizes the XTA configuration of the present invention, shearing mechanism, and multiple combustible load redundancy, while also having thinner leg sections;
[0068] FIG. 10 is a partial cross-sectioned view of one embodiment of the present invention where the attachment portions, frangible portions, and movement stopping elements are all bolted together, and utilizes the XTA configuration of the present invention, shearing mechanism, multiple combustible load redundancy, and separates the compressive and tensile strength elements.
[0069] FIG. 11 is a partial cross-sectioned view of another embodiment of the present invention where one attachment portion, and all frangible portions, are all integral to one another, and utilizes the XTA configuration of the present invention, and shearing mechanism.
DETAIL DESCRIPTION OF THE INVENTION
[0070] The present invention is more particularly described in the following description and examples are intended to be illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. As used in the specification and in the claims, the singular form “a” “an” and “the” may include plural referents unless the context clearly dictates otherwise. A directional term such as “upper”, “lower”, “right” and “left” may not to be limited to the precise orientation specified, but instead such directional terms should be understood to only denote orientations relative to a drawing. Furthermore, the orientation terms of “horizontal” and “vertical” are in relation to a normal mounting configuration, in which the vertical axis is in line with the structures to be held together, and the horizontal axis is generally the plane in which separation occurs. Also, as used in the specification and in the claims, the term “comprising” may include the embodiments “consisting of” and “consisting essentially of”. Furthermore, all ranges disclosed herein are inclusive of the endpoints and are independently combinable. Also, as used in the claims the term “bonded” is defined as an object joined securely to another object by a bonding means which include but is not limited to an adhesive, a heat process, pressure, or ultrasonic acoustic vibration methods, such as ultrasonic welding.
[0071] As used herein, approximating language may be applied to modify any quantitative representation that may vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about” and “substantially” may not to be limited to the precise value specified, in some cases. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value.
[0072] As shown and described herein, various features of the disclosure will be presented. Various embodiments may have the same or similar features and thus the same or similar features may be labeled with the same reference numeral but preceded by a different first number indicating the figure to which the feature is shown. Although similar reference numbers may be used in a generic sense, various embodiments will be described and various features may include changes, alterations, modifications, etc. as will be appreciated by those skilled in the art, whether explicitly described or otherwise would be appreciated by those skilled in the art.
[0073] The reliability deficiencies of prior art designs are explained by the illustrated sequence of FIG. 2A through FIG. 2F. FIG. 2A illustrates a partial cross-sectioned view of the pre-activated state of a typical frangible joint, with an upper clevis 236 made integrally with the two frangible portions 216 and 217. Both frangible portions have a groove in each of them that creates a thinned section known of as ligaments 226 and 227, which act as stress risers for the desired fracture planes. The upper clevis 236 is bolted 242 through the frangible portions 216 and 217 to a lower tang 246. An expansion cavity is formed between the frangible portions 216 and 217, the upper clevis 236 and the lower tang 246, wherein an XTA 201 is placed. This XTA 201 is compressed into a racetrack shaped so that upon inflation it will reshape itself in a horizontal fashion, applying its force to the frangible portions legs 251 and 252. The XTA also contains a single combustible load 211, which is typically HNS high explosive.
[0074] FIG. 2B illustrates a perfectly separated frangible joint. This shows a typical embodiment of prior art in which the combustible load 211, has detonated, and filled the XTA 201 with combustion byproducts and thereby increased the pressure inside the XTA 201. The XTA 201 has rounded due to the increased internal pressure and has applied force outwardly against the frangible portions 216 and 217, which, due to the force, have fractured along their respective fracture planes. The now untethered lower parts of the frangible portions, referred to in the art as legs 251 and 252, have bent outwardly under the continued force exerted on them by the XTA 201. In this illustration it is shown how prior art perceives this outward bending of the legs 251 and 252 to happen in a symmetric fashion.
[0075] FIG. 2C through FIG. 2E illustrates the sequence of a prior art frangible joint that has failed to separate. FIG. 2C shows the state of the frangible joint just after FIG. 2A in which the combustible load 211, has been ignited, and is pressurizing the XTA 201 with combustion byproducts. The XTA 201 has begun to round due to the increased internal pressure and is now applying force outwardly against the legs 251 and 252, causing them to bulge. At this point the force exerted on the legs 251 and 252 is relatively equal, and therefore both ligaments 226 and 227 have a chance of fracturing.
[0076] As seen in FIG. 2D. the right hand side ligament 226 has broken first, and although the force exerted on both legs 251 and 252 by the XTA 201 is still equal, the resistance of leg 251 is greatly reduced, and the XTA 201 translates in that direction more freely, leaving the leg 252 without enough force to break the ligament 227, before the combustion energy of the combustible load is exhausted, as seen in FIG. 2E.
[0077] Shown in FIG. 2F the leg 251 has been bent open so wide that it allows the now unsupported XTA portion 261 of the XTA 201 to expand outside the expansion cavity, thereby stealing combustion energy from down the length of the frangible joint and further compounding the failure of the assembly.
[0078] Most of the following variations of the present invention contain a means of limiting leg travel beyond what is necessary for ligament shear. Some contain shear plates and some contain a recurved XTA. The present invention anticipates any combination necessary to meet launch and separation requirements. The most efficient joints contain all three.
[0079] A version of the present invention is shown in FIG. 3A. This illustration shows a partial cross-sectioned view of the frangible joint. The main features are XTA 301 and two frangible portions 316 and 317. Those frangible portions have a thinned ligament feature, 326 right and 327 left. A combined clevis assembly comprised of 316, 317, 331, 332, 336, and 341. A tang 346 is bolted 342 to the clevis assembly through the lower parts of the frangible portions 316 and 317.
[0080] The second novel feature shown in FIG. 3A is a set of shear plate assemblies 321 and 322 inserted between the XTA 301 and the clevis assemblies central plate 336. The shear plate assemblies 321 and 322 are attached in a way to form a pivot point. That pivot point is centered in the recurved portion of the XTA 301. The free end of shear plate assemblies 321 and 322 touch legs 351 and 352 on the tang 346 side of ligaments 326 and 327.
[0081] The most important novel features of the present invention are stop plates 331 and 332 shown in FIG. 3A. Those stop plates 331 and 332 lap ligaments 326 and 327, and are thick enough to restrict the movement of legs 351 and 352 after fracturing has occurred. A gap between the inside of the stop plates 331 and 332 and the outside of the legs 351 and 352 ranges between one tenth and sixty times the maximum material elongation of ligaments 326 and 327. When the combustible load 311 is activated, gases are produced which raise the internal pressure of XTA 301. This pressure gradually inflates and reforms XTA 301 into a circular geometry as seen in FIG. 3B. The rounding of XTA 301 exerts force on the pivot point between the shear plate assemblies 321 and 322 in the direction of clevis assembly central plate 336. This force is vectored by the shear plate assemblies 321 and 322 toward ligaments 326 and 327. One ligament 326 fractures and leg 351 is pushed toward stop plate 331. Gas pressure from the combustible load 311 builds and the XTA 301 continues to inflate and exert force on the pivot point between the shear plate assemblies 321 and 322.
[0082] FIG. 3C shows the fracture of ligament 327 and the bending of leg 352 against stop plate 332. With even more gas production from combustible load 311, XTA 301 presses the pivot point of the shear plate assemblies 321 and 322 flat which bends stops plate 331 and 332 outwards as shown in FIG. 3D. The stretch of the bolts and bending of legs is mostly reversible so bolt stretch at 342 and legs 351 and 352 applies energy back to the XTA 301 which can then be applied to shearing other unfractured areas elsewhere down the length of the frangible joint.
[0083] Once the continued inflation of XTA 301 has pivoted the shear plate assemblies 321 and 322 past 180 degrees, thrust separation begins. The pivot point now exerts force against the central plate 336 of the clevis assembly. This action forces disassociation between legs 351 and 352 and stop plates 331 and 332 as shown in FIG. 3E. At the same time stop plates 331 and 332 and legs 351 and 352 return some energy from elastic deformation which adds to thrust separation. Of course periodic means to keep XTA 301 and shear plate assemblies 321 and 322 attached to the lower tang 346 must be employed to prevent them from becoming space debris. FIG. 3F shows no further contact between the two stages.
[0084] FIG. 6 represents another anticipated embodiment of the present invention, where the clevis 636, frangible portions 616 and 617, and stop plates 631 and 632 are all made integrally, and are bolted 642 to the lower tang 646. The XTA 601 is in the vertical major axis configuration commonly seen in prior art, where the inflation force of the XTA 601 is configured to apply force directly to the legs 651 and 652. The XTA 601 is shown having only one combustible load 611 due to the inefficiency of the XTA orientation and the lack of shear plate assemblies. This design is very similar to prior art in that it has the basic configuration, however by forming or cutting the grooves 656 and 657 to form ligaments 626 and 627 at an upward angle, instead of straight inward from the side as shown in FIG. 2A, stops 631 and 632 are automatically created. This configuration includes integral stops that are an improvement over prior art by conservation of combustion energy through limitation of un-necessary leg travel. This design will probably be such an improvement over prior art that reliability could be increased to 99.95% reliability.
[0085] Another anticipated variation of the present invention is shown in FIG. 7. This version demonstrates an embodiment of the present invention that only requires a single frangible portion 717, a single double strength ligament 727, and a single movement stopping element 732, which are all integrally formed together with the upper clevis plate 736, and bolted 742 to the lower tang plate 746. The stop plate 732 provides a large reliability increase through greater efficiency. Also present in this embodiment is the forming of the expansion cavity between the clevis 736, the single leg 752 of the frangible portion 717, and the lower tang plate 746, wherein the XTA 701, containing a single combustible load 711, is placed. Although FIG. 7 shows an inefficient XTA configuration, turning of the XTA 701 and the insertion of shear plate assemblies are also anticipated, and would allow for multiple combustible loads to therefore be utilized.
[0086] Shown in FIG. 8 is another anticipated embodiment of the present invention. This configuration having the clevis 836, integrally formed with two frangible portions 816 and 817, ligaments 826 and 827, and post fracture movement stopping elements 831 and 832. Both frangible portions also have formed legs 851 and 852, that bolt 842 to the lower tang 846. This embodiment also utilizes the advantages of shear plate assemblies 821 and 822, a horizontal recurved XTA 801 containing three combustible loads 811, 812 and 813, and a lower tang 846 that has a curved shaped top to limit the expansion of the XTA in the undesirable lower corners of the expansion cavity, while also having a concave upper expansion cavity which provides customized post fracture timing and thrust separation force. This design is highly efficient at applying combustive energy to the main task of joint separation on both sides of an entire frangible joint section. That high efficiency in turn allows for multi-fault tolerance because of a wide operational window that allows for multiple combustible loads to be placed within the XTA. The integral stops provide a low mass means of stopping the post fracture leg movements. The tapered legs create launch stability by lessening the possibility of compressive buckling.
[0087] FIG. 9 features another anticipated embodiment similar to FIG. 8, wherein the legs 951 and 952 are the same thickness as the ligaments 926 and 927. With the use of shear plate assembles 921 and 922 in the present invention, which act as stress concentrators, stress risers in the form of a thinned sections are unnecessary. This design is highly efficient at applying combustion energy to the main task of joint separation on both sides of an entire frangible joint section. That high efficiency in turn allows for multi-fault tolerance because of a wide operating range that allows for multiple combustible loads to therefore be utilized.
[0088] FIG. 10 shows another anticipated embodiment of the present invention. This variation features the physical separation of compressive and tensile elements. This configuration has an upper clevis assembly comprised of a clevis 1036, two frangible portions 1016 and 1017, ligaments 1026 and 1027, and upper compressive elements 1066 and 1067, that are all bolted 1041 together. This clevis assembly is bolted 1042 through the frangible portions 1016 and 1017 to the lower tang assembly. The lower tang assembly being comprised of the tang 1046, and two lower compressive elements 1071 and 1072. In this configuration the lower compressive elements 1071 and 1072 also act as the post fracture movement stopping elements for legs 1051 and 1052. This embodiment also utilizes the advantages of shear plate assemblies 1021 and 1022, and a horizontal recurved XTA 1001. This allows the frangible portions to share the compressive launch load with the compressive elements 1066, 1067, 1071 and 1072, and therefore can be lighter weight than other designs. This configuration is advantageous when the compression to tension launch load ratio is greater than one. That ratio is typically 3.5:1 for a Taurus XL rocket. Since the frangible portion of a rocket only applies to tension, there are opportunities for weight reduction. Both the combustible load and the XTA mass can be reduced. Also, since minimum shearing energy can be reduced by 3.5 fold through the separation of compressive and tensile elements, the shock impressed on the launch vehicle and payload during stage separation can also be reduced. In cases where the coefficient of friction between the legs 1051 and 1052 and the movement stopping elements is necessary to create a leveling effect down the length of the joint, the fractured legs should be stopped by the upper compressive elements 1066 and 1067. Conversely, if the free movement of the stages after ligament fracture is advantageous, the legs 1051 and 1052 should be stopped by the lower compressive elements 1071 and 1072. This design also allows for multi-fault tolerance because of a wide operating range that allows for multiple combustible loads to therefore be utilized.
[0089] FIG. 11 illustrates another anticipated embodiment of the present invention, where the clevis 1136, and frangible portions 1116 and 1117 are all made integrally, and bolted 1142 to the lower tang 1146. This embodiment utilizes the advantages of shear plate assemblies 1121 and 1122, and a horizontal recurved XTA 1101. This design is efficient at applying combustive energy to the main task of shearing ligaments 1126 and 1127 and does provide a means of thrusting separation after fracture is complete.
[0090] Although exemplary embodiments of the invention have been shown and described, many other changes, modifications and substitutions, in addition to those set forth in the above paragraphs may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of this invention.
