ai-aerospace/ams_data_full_2000-2020 huggingface dataset:
position Forward clamprelease Centeractuator energizedm m r Forward clampclosed Rearclampreleased Centeractuator de-energized! Rearclampclosed Figure6-Energen's linearstepper motoriscapable oflongstrokes usingapairofclamps anda translating actuator operated inaindexing sequence. NextGeneration SpaceTelescope Undercontract totheNational Aeronautics andSpaceAdministration andaerospace companies, Energen hasreceived several contracts todevelop anddemonstrate aseriesofcompact actuators for useontheNextGeneration SpaceTelescope (NGST). NGST,aconceptual designofwhichisshownin Figure7,isa$500millionprojectplanned forlaunchsometimein2007toreplace theHubble Space Telescope. Itwillhavealarge6-8meterdiameter lightweight, segmented primary mirrorthatislaunched inafoldedconfiguration andthendeployed inorbit.Thelargeaperture ofthetelescope andpassive cooling technology employed bythetelescope resultsinahighresolution visibleandnearinfrared observatory thatoperates at30-50K. Figure7-Aconceptual design oftheNGSTshowing thelargesunshield withthetelescope behind it.Thesegments ofthe8-mprimary mirrorcanbeclearly seen. Whereas ontheHubble theprimary mirrorisultra-low expansion glassstructure similartoground-based telescopes, theNGSTwilluselightweight, adaptive opticstechnology intheconstruction oftheprimary mirrorsystem. Themirrorwillconsist ofseveral petals(orsegments) thatwillunfoldafterlaunch. Each petalwillconsist ofarigidcomposite backstructure ontowhichismounted alightweight reflective surface. Anarrayofactuators connect themirrorsurface totherigidbackstructure andareusedtoalign 141
themirrorsegments andtocorrectimageaberrations resulting fromthermalgradients andotherexternal phenomena. Energen's magnetostrictive actuators arebeingusedinthedesignoftheAdvanced MirrorSystem Demonstrator Project-ascaledemonstration ofmirrortechnology fortheNGST.Successful completion ofthisdemonstrator willleadtoaflightdemonstration totestthemirrorcharacteristics inazerogravity environment. OtherApplications Otherapplications ofthesemagnetic actuators takeadvantage oftheirhighforcecapability, largestroke andrepeatability. Energen, Inc.isapplying linearactuators tosuchdiverseapplications as .Highconductance heatswitches forcryogenic refrigerators. Heatswitches areacriticalcomponent oflowtemperature adiabatic demagnetization refrigerators. Theyprovidehigherthermalconductance thanothertechnology atsub-kelvin temperatures enabling moreefficient refrigerators forhighsensitivity instrumentation anddetectors. Theserefrigerators are beingdeveloped byGoddard SpaceFlightCenterforfuturespacemissions suchasSTEPSand Constellation-X. ,Resonant frequency controlofRFcavitiesforparticleaccelerators. Thehighforcecapability combined withthesub-micron positioning capability ofEnergen's linear steppermotorarewellsuitedtothisapplication. Energen hasbuiltaproof-of-principle demonstration actuator forcavitytuningandispresently developing newgeneration oftuningsystemthatwill completely eliminate themechanical tunersystempresently usedbyJefferson Laboratory inNewport News,VA. .Activevibration control. Energen isapplying itsactuator technology toactivecontrolofvibration. Withstate-of-the-art accelerometers andcontrolelectronics, robustactivevibration controlsystems arebeingdeveloped forbothcryogenic androomtemperature applications. Magnetic vibration controlismoreefficient thanthecurrently available piezoelectric systems forcontrolling low-frequency, high-amplitude vibrations. Conclusion Energen, Inc.hasdeveloped actuators andlinearsteppermotorsforoperation incryogenic andvacuum environments. Thesesystems arebeingappliedtoavarietyofsystems whereprecision positioning and highforcecapability arerequired inacompact package. Theactuators andsteppermotorsdonotuse anylubricants makingthemexcellent candidates forultraclean environments suchascleanrooms. 142
ASeparation System Solution fortheInterimControl Module BrianWhalen' Abstract TheInterimControlModule(ICM)isapropulsion andattitudecontrolplatformfortheInternational Space Station(ISS)builtbytheUSNavalResearch Laboratory (NRL).ICMisdelivered toISSviatheSpace Shuttle,whereitisseparated fromitsstructural supportcanisterandmovedintodockingpositionusingthe ShuttleRemote Manipulator System(SRMS). ThePinExtraction Mechanism (PEM)isoneofthe mechanisms thathelpensuretheseparation ofelectrical connectors andprevents re-engagement ofthe pinsandsockets. Thispaperdescribes theICMseparation system,thePEMandoperational details. Introduction ThePinExtraction Mechanism isasingle-use mechanism thataidstheInterimControlModuleseparation fromitssupportcanisterintheSpaceShuttlecargobay.Separation isaccomplished byutilizingasystem ofeightPEMsattheseparation planetoensurethede-mating oftwo41-pinseparable connectors, each showninFigure1.ThePEMsystemminimizes forcesontheSRMSandprevents re-engagement orrecontactoftheconnector halvesusingaratcheting andlockingplunger. EachPEMisaself-contained unit thathousesaspring-loaded plungerthatpushesthevehiclesapartwhileovercoming pinandsocketfriction fromtheseparable connectors. ThePEMsarelocatedonthesupportcanister, asillustrated inFigure2, andarereturned toEarthaftertheSpaceShuttledocksICMtotheISS. Figure1.PinExtraction Mechanism andSeparable Connector Halves. *U.S.NavalResearch Laboratory, Washington, D.C. Proceedings ofthe34_Aerospace Mechanisms Symposium, Goddard SpaceFlightCenter,May10-12,2000 143
SRM_ Figure2.ICMSeparation Configuration andPEMLocation. Background TheICMvehicleisbasedonaprevious vehicledesignthatwasafree-flying satellite onceseparated from thecanister. Theoriginal satellite usedaspringseparation system toseparate theseparable connectors showninFigure1withnoriskofre-contact. WhenNASAdetermined thattheSRMSwasnecessary toseparate theICMfromtheCanister, the separation became morecomplex. Duetotheflexibility andconfiguration oftheSRMS, itishighly desirable tominimize theloadsattheendoftheSRMS. Analysis provided toNRLbyNASApredicts that theICMvehiclewillmovelaterally in,androtateabout,theX,Y,andZaxes.Thisintroduces are-contact riskfortheseparable connectors. Thus,newhardware needed tobedeveloped toprevent re-contact. 0ulil¢._' hl_,Nut_-il||o._,..bl. I Figure3.ICM/Canister Separation Joint. Theseparation systemconsists ofeightseparation joints.Ateachjoint,thereisacup-cone interface with aboltthrough thejointasinFigure3.TheICMsideofthejointcontains aboltcatcher whilethecanister 144
sideofthejointhousestheseparationnut.Onthecanistersideoftheseparationplane,invarious locations,aretwoseparableconnectors, PEMs,andtwoseparationguides. ThereexistedamountingpatternforaspringseparationsystemontheCanister,somodification wasnot necessary. InanefforttominimizetheenergyimpartedintotheSRMS,atradestudywasperformedto identifythebestconfiguration forseparationsprings.Withinthistradestudywereotheroptionssuchas "connectorretractors." ThePEMwasthebestoptiontoreleasetheseparableconnectorhalveswhile preventingre-contactbecausePEMsaresimple,theyprovide3:1forcemargin,andtheSRMScouldhandle theenergy.TheresultiseightPEMsinfourpairsaroundthecanisterasshowninFigure4.Onepairof "strong"PEMs(2springs)ateachseparableconnectorjoint,andonepairof"light"PEMs(1spring)ata joint90°aroundthecanister.Thisprovidesa"four-point"planeforincidentalre-contact. Figure4.Canister Separation System Configuration. Theseparation sequence isasfollows: 1.AftertheOrbitercargobaydoorsopen,theSRMSgrapples theICMandrotatestheICMand Canister up25degrees (asshowninFigure2). 2.TheOrbitercrewfirestheseparation nutsina4-2-2sequence. Thisminimizes release energy imparted intotheSRMSwhilestillreleasing inasymmetric pattern. 3.ThePEMspushtheICMawayfromtheCanister withenough energytoseparate theseparable connectors whilelockingthePEMplungers out. 4.Thecup/cones andseparation guideslimittranslation androtation ofICMwithrespect tothe Canister forupto1.27cm(0.5inch)ofICMmovement alongtheXaxis. 5.IftheSRMSflexesandtheICMre-contacts theCanister, thePEMswillreacttheloadsandprevent connector orguidere-contact. 6.ICMistranslated abovetheODSandberthed totheODSinpreparation forISSdocking. 145
Requirements Therequirements tosafelyseparate theICMfromthesupport canister include thefollowing: a.Mustprevent re-engagement oftheseparable connector shells b.Mustwithstand impactloading bypotential re-contact ofICMandcanister c.Maintain a3.-[force marginonseparaUng theseparable connector halves d.Impartacceptably lowforceontheSRMS e.Singlefaulttolerant design f.Noelectrical powertofunction mechanism g.Fitexisting fastener, holepatternandpocketdepthontheCanister h.MustbeEVAcompatible Theaboverequirements provided constraints fordefining force,volume, mounting pattern, testpass/fail criteriaandcertaindesignaspects. ThePEMwasdesigned tofulfillalloftheserequirements withasimple passive mechanism. Analysis Tounderstand themagnitude oftheforcesrequired forseparation oftheconnectors, apull-test was conducted usingafullypopulated flightDeutsch 38194-61-42PN (41-pin) separation connector selected for thedesigninterface. +Testdata,sampled inFigure5,showed thattheconnector dragforceaveraged 117N (26Ibf)perconnector. Thenominal PEMoutputforceisalsoshownonthisgraph.Thisshowsthatthe PEMprovides largeforceandstrokemargins toseparate theseparable connector. 450 400 $50 300 _250 150 100 50& I & II eeNk0 • 0# ,• , .... 0.00 0.20 0.40 0,60 0.80 1.00 1,20 Stroke(¢m),ik && II • • 1.40--0--Separable jCon_r Drilg(N) J--.l.--PEMForceCN) JIPEM,1.5:1Ratio I--A--PEMForce(N) J2PEMs,3:1Ratio Figure5.PEMPerformance Compared ToSeparable Connector DragForce. Theworst-case impactenergywascalculated fromtheseparation event,whichincludes activation energies offourNASAStandard Initiators andeightPEMenergies. Theenergyfromanincidental re-contact cannot exceed theenergyputintotheseparation, soonePEMisrequired tobecapable ofreacting thetotalenergy intheseparation. 146
Design andOperation Ratchet Compresslon Bottom Ratchet Compression PlatetRatchet Housing Bushing Plunger Spring ICM("Strong" PEMOnly)  Preload Plate Base Canister Ring Figure6.PEMDesign. ThePEMdesignevolved aroundtherequirements andavailable commercial springs. Asectional viewofa PEMisshowninFigure6.OnekeypartofthePEMdesignprocess wastoprototype thedesigntocorrect designflawsthatcouldotherwise severely impactcostandschedule. Several aspects ofthePEMdesign werechanged aftertheprototype wasfabricated, assembled andtested: 1.Improved clearance forslidingandinterference fitparts.Itwasnecessary toincrease ratchet pocketvolume whenBray602wasaddedandtheratchethousing partswereinstalled. Incorrect pocketdimensions prevented properslidingoftheratchets because itdidnotinclude enough volume forlubricant. 2.Propersurface finishes toincorporate slidingpartsandpart-to-part electrical conduction (grounding). TypeIIIhardcoatanodizing wasapplied totheflightdesign, withareasmasked for iriditeatcontact pointsbetween matingpartsforelectrical conductivity toground. 3.Newsprings withlongerfreelengthwereinserted toachieve necessary margins because the original springs wereoutside ofthecatalog specifications after"removing theset."2 Theprototyping process allowed developmental teststobeconducted andgreatlyassisted inwriting assembly andtestprocedures aswellasdesigning testfixtures. Partofthisdevelopmental testingincluded multiple impacttestingatupto10timestheimpactenergywithsuccessful cyclesbeforeandafterthe impacttests. ThePEMisinthecompressed stateuntiltheseparation isinitiated byrelease oftheseparation nutsthat attachandpreload theICMtotheCanister. Oncetheseparation nutpreload isremoved, thePEMsprings arefreetoovercome thepin/socket frictionintheconnector. 147
ThereisasingleplungerineachPEM.Theplungerispreloadedwithtwonestedspringsinthe"strong" PEM;oneawavespringandtheotheracompression spring. Thewavespring,whichhasashorterstroke andalargerdiameter thanthecompression spring,overcomes mostofthepindragwitha111-N(25-1b) force.Thecompression springaroundtheplunger appliesa77-N(17-1b)forceandpreloads theplunger with a35-N(8-1b)forceattheendofitsstroke. Ratchets serveasaredundant lockoutfeaturefortheplunger. Therearetworatchets perPEM,each ratchethavingitsowncompression spring,whichpreloads ittothestepsontheplunger. Astheplunger strokes out,theratchets moveinandprevent plunger movement intheopposite direction. Eachratchet operates withasinglecompression springthatpushes itagainst theplunger. Bray602isthelubricant usedonallmetal-to-metal slidingsurfaces. Theplunger slidesthrough two bushings madeofVespel SP3anddoesnotrequirelubrication. Test Theloadtestingofaspringsystem suchasthePEMiseasyatacomponent levelusingatensile! compression testmachine. Thewavesprings andcompression springs weretestedmultiple timespriorto assembly tocharacterize eachspring,remove theset,andgroupthesprings intosetswithmatching spring constants anddeflections. Sincethespringvaluesallchanged whenremoving theset,itwasnecessary to testeachspringinstead ofblindlytrusting thevendorspecifications. Matching springvaluesforgroupsof springs isimportant toensureanevenkick-offforceacrossthevehicleattheseparation plane. Testing thePEMasasubsystem withasimulated jointhasproventobeadifficulttask.Thetestfixture showninFigure7issimilartoasection oftheCanister forward ring.Intheconfiguration shown,thetest fixturedoesnotworkasdesired. Although thisisanearduplicate ofaflighthardware section, itisnota goodrepresentation ofthesystem because onefixturealoneoversimplifies theseparation system. Figure7.PEMTestFixture. Afreebodydiagram showed thatthePEMsonlyseparate theplatesatananglewhiletheseparable connector staysengaged. Thishappens evenwithguiderails,whichbindfromthemoment created bythe configuration. Thesolution camefromtheaccidental wisdom offabricating twotestfixtures. Theoriginal intentwasto modifyonefixtureforvibration, andusetheotherfixtureforotherenvironmental tests.Nowbothfixtures are 148
beingmodifiedtoattachthefixturesside-by-side, oneoriented symmetrically opposite fromtheother.This balances theforcesandmoments onthefixtureandmorecloselysimulates thesystem. Itisnowpossible toseparate theplatesproperly asasmall-scale system simulation. Itisimpractical todoafullsystem levelseparation testduetothesizeofthevehicle, riskofdamaging flight hardware, andschedule limitations. Therewillbeasystemlevelpyroshock acceptance testwheretheICM andCanister arematedandtheseparation nutsarereleased. ICMwillbeliftedoffoftheCanister toverify thePEMplungers extendandtheratchets function properly. Thisdoesnotconstitute agoodfun-scale test because itwillnotenvelop themaximum possible translation androtation bythevehiclewhileitisinflight configuration. Sothequalification ofthePEMsisbaseduponcompilation ofthethreetests:I)PEM component, ii)subsystem separation, andiii)ICMpyroshock. Conclusion ThePinExtraction Mechanism isasimplemechanism thataidsinthekinematics ofvehicle separation. ThePEMmeetsNRLandNASArequirements andallowstheICMandexisting Canister hardware toeasily adapttoadifferent typeofseparation. Prototyping thedesignallowed fordevelopmental testsanddesign improvements. Theoriginal testfixturedidnotworkasdesired, however fabricating multiple testfixtures leadtothecorrectfixturedesignchange andsubsystem testapproach. NRLisqualifying thesystem witha combination ofcomponent, subsystem andsystem leveltests. References 1.Whalen, Brian.SSD-TR-IM022 -ICMCanister JointSeparable Connector PullTestReport. USNaval Research Laboratory, Washington, DC.24September 1999. 2.Shingley, Joseph andMischke, Charles. Standard Handbook ofMachine Design. McGraw-Hill Book Co.,Inc.NewYork,NY.Copyright 1986.Pages24.19-20. 149
TheDevelopment ofanUltraLowShockPyrotechnically Actuated Separation Nut FredSilverman" andJerryO'Quinn" Abstract Asspacecraft havebecome vastlymoresophisticated withamyriadofsensitive andcomplex components, theconcern caused bymechanical andpyrotechnic shockhasincreased. Looking forsolutions tothe problem Hi-Shear Technology Corporation (HSTC) isdeveloping anultralowshockseparation nutthat reduces thepeakoutputshockbyapproximately 50%oftheHSTCflight-qualified low-shock separation nuts,whicharepresently oneofthelowestmechanical/pyrotechnic shockproducing devices. Theultralow shockseparation nut(Patent CaseNumber 4931)usesarotorfeaturethatconverts muchoftheshock energyfromanaxialdirection intorotation andincreases thepreload release time,thereby decreasing the peakoutputshock. Introduction Aseparation nut,whichisaseparable threaded fastener, istightened toholdtwoobjects securely together withanaxialpreload onthefastener. Thestructure oftheseparation nutinherently minimizes mechanical shockloadsonthecontiguous structure, whicharedeveloped whenelements oftheseparation nutare abruptly separated fromoneanother. Intheearlydaysofaerospace, reliability ofseparation wasthe primary objective. Iftheseparation nutfailedtorelease oncommand, theentireprojectwouldbeimperiled. Forthisreasonredundant fasteners wereoftenusedasabackup.Reliability isstilltheprimary concern, butafteritwassolved, attention turnedtothereduction ofmechanical shock,whichisunavoidably exerted onthesurrounding structure whentheseparation nutisreleased. Energythatispotentially asourceofmechanical shockisnecessarily storedinthefastener systemwhenit iscoupled tobothobjectsthataretobeheldtogether. Customarily onepartofthefastener, usually its threaded nut,isfixedtooneoftheobjects. Aheaded, threaded boltengages theotherobject. Itis threaded intothenutandtightened. Theresulting axialtensilepreload storedinthenut/bolt combination is essential tothetightness ofthejoinder, butalsomustbeexpended whenthefastener elements are separated. Theresulting shockisanabruptaxialforce. Another sourceofshockcomesfromthesegmented threaded partofthenut.Thethreads areformedon insidesurfaces ofsegments thatareheldagainst theboltbyanexternal removable retainer. Whenthe separation nutistobereleased, aretainer movesawayfromthesegments andtheymoveawayfromthe bolttorelease it.Therapidmovement andabruptarresting ofthesegments andretainer thereby contribute totheshock. Thefinalsourceofshockisthepyrotechnic actuator. Itisevident thatashockloadwillbe generated byitsdeflagration. Thepyrotechnic chargeloadisdependent ontheforcerequired torelievethe retainer's frictionforce.Asthepreload increases, thepyrotechnic shocksourceincreases proportionally. Although fairlylargeshockloadscanbetolerated inheavier structures, thedevelopment ofverylightweight structures suchasspacecraft antennas haslowered thetolerance forsuchforces. Hi-Shear Technology Corporation isproviding separation nutdesigns inbothpyrotechnic andnon-pyrotechnic devices 1thatcan reducethisshockoutput. •Hi-Shear Technology Corporation, Torrance, CA Proceedings ofthe34_Aerospace Mechanisms Symposium, Goddard SpaceFlightCenter,May10-12,2000 151
LowShockSeparationNutdesignissimplymovedoutofthewaybyalightcoilspringoncetheboltpreload isrelieved,allowingthesegmentstogentlyseparate.Thisreducesmechanical shocksignificantly. 1. 2. . 4. 5. 6.Highpressure gasproduced byPowerCartridges isintroduced intothe pressure chamber. Locking pistonmovesawayfromthebolt,unlocking thethreaded segments engaging thebolt.Movement, ofthelocking pistonisstopped bythe separator. Thiscollision isisolated fromthenuthousing andsurrounding structure, transmitting averylowshocklevel. Threaded segments displace radiallyawayfrombolt. Separator lockssegments inopenposition. Ifoptional ejectorisincorporated, ejectorthrustsboltoutofstructure joint. Structure jointiscleanlyseparated.  360oROTATABLE MANIFOLD POWER CARTRIDGE HOUSING  BUFFER ZONE  PRESSURE  CHAMBER 0LOCKING THREADED _1 ,--_ STRUCTURE _ FLANGE BEFORE ACTUATION AFTERACTUATION 1.Boltisthreaded fullyintonutseg- 1.Gaspressure actsonlocking piston, ments, moving itawayfrombolttounlock 2.Nutsegments arefullysupported by threaded segments. lockingpiston. 2.Segments displace radially awayfrom 3.Structure jointisclamped uptotension bolt. ratingofbolt. 3.Boltejectsandstructure jointseparates. Figure 1.HSTCLowShockSeparation NutSequence ofOperations TheRotoroftheUltraLowShockSeparation Nutdesignmakesallofthispossible. TheRotorfitsbelowthe seatthatsupports thesegments duringpreload. BoththeRotorandseatfeatures arematinghelicalloadbearing surfaces. Thehelicalsurface feature optimized anglesinordertocauseauto-rotation underaxial load.PinslocktheRotorandseattogether toprevent rotation. Actuation ofthepyrotechnic initiator 153
withdraws thepinsallowing theRotortoturn,whichallowstheseatandsegments todrop,relieving the preload. Although thefunction timeoftheUltraLowShockSeparation Nutexceeds thatofthe9400series nut,itisstillshortenough tosupport theneedforsimultaneity inmulti-nut applications. J G"_Wllm illWI Figure2.HSTCUltraLowShockSeparation Nut ShockOUtDUtExDeriment Thefollowing experiment wasperformed tovalidate theUltraLowShockSeparation Nutconcept withthe standard HSTCSN9400 seriesseparation nut.Bothnutswerepreloaded withaloadcellto10,000-N (2,247-1bf) withanM12-1.75 (0.5-20in)UNJFclass-3 MS-bolt. Foreachtest,theseparation nutwas centrally mounted toa61-cmby61-cmby1.9-cm(24-inby24-inby0.75-in) horizontally suspended aluminum plate.A2.54-cm by2.54-cm by2.54-cm (1-inby1-inby1-in)aluminum blockwasmounted 15.24-cm (6-in)fromthecenterlocation oftheseparation nutontotheshockplate.ThreeeachModel7225 Endevco accelerometers weremounted orthogonal totheblockinordertomeasure theacceleration output ineachaxisfromthea-(_tuation event.EachnutWastestedindividuaily withasingleinitiatoratroom ambient condition foratotalofthreeshotspernut.Figure3presents ashockresponse spectrum (SRS)for eachofthetestedseparation nuts. AseachoftheSRS'sdemonstrate thattheUltraLowShockSeparation Nuthasappreciably reduced the shockoutputcompared totheHSTCSN9400 LowShockSeparation Nut.At100Hz,theSN9400 Low ShockSeparation Nuthasapeakresponse of245m/s2(25-g)andtheUltraLowShockNutsis49m/s2(5g);at1,000Hz3,430m/s2(350-g) and588m/s2(60-g);at2,000Hz18,620m/s2(1,900-g) and3,430m/s2 (350-g); andamaximum peakresponse at3,500Hz34,300m/s2(3,500-g) and5,500Hz14,700m/s2 (i,500-g) respectively. Thisismorethana50%reduction inpeakshockoutputintheaxialdirection. 154
PARTN'GMBER , PROCEDURE #; Figure3.AxialShockComparison between theSN9400 andtheUltraLowShockSeparation Nut Summary TheHi-Shear Technology Separation SN9400 NutSerieshavedemonstrated lowoutputshockperformance andhasbeenthechoiceonnumerous criticaldeepspaceapplications whereshockoutputiscritical. As theAerospace Industry transitions tosmaller payloads whereshockcriticaldevices arenearproximity to pyrotechnic actuation devices, thesedevices' shockoutputbecome moreandmorecritical. Inresponse HSTCisdeveloping aPyrotechnically Actuated UltraLowShockSeparation Nut(Patent CaseNumber 4931)thathasdemonstrated anapproximate 50%reduction inoutputshockcompared totheHSTC SN9400 separation nut. Thenextiteration fortheHSTCUltraLowShockSeparation Nutistohandlepreloads inexcess of4,500-N (20,000-1b,) withanM12-1.75 (0.5-in)MS-bolt, andfurtherimprove onitsreduced shockoutput. References 1.Patent Number 5,248,233, "No-Shock Separation Mechanism", Richard G.Webster, (Hi-Shear Technology Corporation) September 28,1993 2.Patent Number 3,926,090, "Separation Nut",James WBunker, (Hi-Shear Technology Corporation) December 16,1975 3.PatentCaseNumber 4931,"Reduced ShockSeparation Feature", O'Quinn et-al,(Hi-Shear Technology Corporation) February 1,2000 155