|Publication number||US2857845 A|
|Publication date||Oct 28, 1958|
|Filing date||Sep 29, 1954|
|Priority date||Sep 29, 1954|
|Publication number||US 2857845 A, US 2857845A, US-A-2857845, US2857845 A, US2857845A|
|Inventors||Seavey Frederick R|
|Original Assignee||Olin Mathieson|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (10), Referenced by (15), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Oct. 28', 1958 F. R. sEAVEY EXPLQSIVE DEVICE Filed Sept. 29. 1 954 FREDERICK R. SEAVEY AGENT .Thisfinventionrelates enerally'to explosives andmore particularly tote a1 ynovel; xp1os`io-retarding coupler for lengths: ofdetonating fuse; 'fl
4Itifisdesirabler-in some fblastin inquarr-ies :and: in; someigsrface -mines to shoot successively severalv explosive charges `which have been properly spaced `oven an areato' beffblastedwithoutfitbeing necessal-'yfioimpersonnel?y onation sof; f thes places, ein :the area detonating fusejplacedinvthe drillhole withhthe vexplosive charge. l*andi extending to; afcomnion trunk line 'of ysimilar` detonating afuse" g operations particularly to enterithe area .between shots; Det- `explosive chargesilocateld i fat" various iseaccomplished byineansv of` lengths of` i ing i *lengths of detonating Afuse 'and for f'retiarding the` initiation' of the second "length of idetonating fuse which does not req'uirelprecise assembly With' theifuse Ltofbe blasfugij A CH v-detonating'fus ,Y .E .t i 1 Figure `2` illustrates,`"1n` a fragilientaryside view, "partiallyl.
another embodiment ofzthe inventionhaving a Abeit-.SafelyV initiated."-r v'The simultaneous Eexplosion of. all 'l thegchages is undesirable fbecause of the 'degree v ofearth Y vibration produced: 'thereby-sox` it] is desirable to `provide delayifelementshor,xeXplosionfretardinglf.devices between the-lengths ofdetonating'rfuse feitherlin each branch lineor,;-ativariousipoints `tin f the Ytrunk linev in order to :lire `the explosive f.ch`arges fsuccessively. uf One such? device Vwhich I has;` :been `proposed i fforifthis I purpose fhas ia deiag'r-ating charge butted up against one length-of'detonatingfuse and: aniigition mixture buttedup 1against thef other length ofsdetonating fuse zwith af :delay c between. In this type. f"dvicethe`naine-fromme `rst length of :fusewignites the lignition mixture 'which' in` turn charge l interposed `thereif gnites1the-delyfcompositionandithe deilagrating charge. It has:been-''found` in'iprctice, '.howeve'rl; that such 5a` device depending;` uponezthe'fflamef of ther burning detonating', fuse i foriignitic'ins Vis not entirelyasatisfactory\'because Vityfrequently: ifails i toc-ignite:r the i second i length of detonating f fuse.; Inforder tofins'ure ignitionof the rsecond length,
assemblyrisinot always :obtained in practice Moreover, considerable:diiiicultyfliasfbeen experienced in' c Which might Abe-"atzsleast partially.` responsible for `'the ignitionA failures.
makingrsucli ai device'scientlywaterproof for use at manyxblastiiigsitesisoit has beenznecessary for `the manu# facturen ftovspply andevicel having short lengths i Vof `detsure waterproofness A l y containing `both =anfiinitiatingachargeandv thej quantity of secondary;explosivesvfinfthesefsocalled Vfuse tails. `Itvisfthe'reforei `anfzbject fof invention to provide a t is undesirable to shipv packages advantages; fzfAnotl'neri'object ofthisf-'invention is to providel;anaexplosionfretarding vand'ficonnecting` means-for ir'nproved functioning.y i charac ristics. ,fujrtlier objectwofthis;'inventionisto c osiye device adaptedqtobe ,interposed belength of ydetonating fuse fhavin vice g v,with l the fr Ordinarily, in practicing o Y, facilitatel assembly' j 7of fthe @various components fof the 2.o,V device, it 'is preferred to *make the/ explosin Vretaitding explosivechargeanda conventionalv det-V.,l
i of cyclonite 1" yare operative f o and which libe toV the trade vwithout detonating fuse'f 'attached `tl:n=.'retc` The foregoingobjectsfas' wellfas thesiwill become",
apparent* from i 'the followingf description 'reference' to the accompanying drawing invvliich:v Figure l illustrates, one embodiment of this inV section, o c different type `of, centeriire percussion type primer;`
Figure `-3 illustrates, in a fragmentaryside view, partially` 'i in-section, anotheremb rimr'e primer; and" Figure 4 illustrates, in afragimentary side View, partialliy` 1n section anotherembodimentofzthe invention having all',
stab'intiated type primer.'
ona'ting `fuse having an' explosio includes a'percussion' type ignition assembly. Preferably, the invention provides `ahtulpuvllar` coupling d'eviceltforI "detf` onating fuse which contains" anl explosion-rtardinghelement'having apercssion ignitionlassembly adjacentfone,"k
adjacent the fother'end deronating'c'hargc and a delay' means' interpo'se-d` 'between'- the and` detonating charge.'
element by pressingthe' etongatirlg a suitable delay composition charge fin openl and havingv a ,perforat after'close the open endof the'"detonatrVcaselbyA insertlingY aconventional shotgun cartridge' priiner assembly.
Such an` assembly of 'battery cup," anvil fand-primerl cup containinga 'suitablev4 composition is ideally suited'` for the purpose 'because o o the delay compositionlbuti't also'ha it is inserted inthedetonatjsrcase.`
lacquer or other sealing"material,
positioned within thentulbe Aaiij'acent'o.thatc endof theas f sembly having the' jpercussion primer and-indental o in'thetube `v vz`1ll`n=l.far eachend of the tuber-,1 to stop the detonatingffuse `whenwit isla'ter insertedin.- l
tions are placed the tube; o v ,v
In order vfurther `to is a description of one to the accompanying drawing: .t v
In the embodiment ,shown hin Figure V1.,.aboutl3 grains,. .pressednin.aY 2conventional aluminum -p detonator'case Z'underfa loadof about 80 poundsV dead` Weight. Immediately;Hanovre.v .,theg cyclonite `(cyclotri-- methylenetrinitramine) ,1,I `separate j charges` 4lofA i about ^521/2 ig; V
grains of lead azide.'V 3, abontly/zgrain oileadfstyphnateA composed, lof aboutrv p rngethallicl lead", powder, `about 25 selenium` powderyY about` .4% potassium-o chlorate and i Y; about 5 Z1 barium, nitrate are each pressed underrsimilar a pressures.` An'aluniinumjerrule having a central per- `foration l7 in the bottom thereof and of such diameter `rn 'a Y iongifudiai `'sectional viewgf invention attached Ito` lengths l.of
odirnent offtlie inverition".liavingafv Generally speaking, the' objects i of this.: 'invention i' are accomplished by providing acoupler for lengths of `dettarding elementwhich vention; in.` order V tojv y c c o l o o 4ottominside the'detonatoij"f1-` case` and adjacent the delay. composition, @and toftheie.- l
it isv not., onlycap'ablc of` AignitingI I imensions such Vthat ,1. 1t can be'readily assembled Vv'v`itl4,aconventional "detonator `case.'` `order` to Ainsureltliat no moisture can Venterotlziis. i. assembly, it is rvpreferredtola'cqueor. thebattery cupbefore, t A 'JAftelr insertion of the primer, the entire assemblyI iisldlpped vassuitable a n `The resulting assembly is then yplracedjin Val suitableitubefadapterl,totQ*overV they a' rinspin .'srroperly i the@andererepentir? mbodirnent thereof withreference g as to form a slidableitincase is placed over the delay composition and a shotshell primer designated generally by the numeral 8 composed of a battery cup 9, primer cup 10 containing priming mix 11 and anvil 12 is inserted in the I11,Q11fh0f y the. detonator case2. This shotshell primer 8.is.dipp ed,`infalnitrocellulose lacquer which is permitted to dry before it is inserted in thedetonator case 2. After primer 8.has been properly positioned in the mouth of the detonator case 2, the mouth of the entire assembly is dippedin the nitrocellulose lacquer to insure waterproofness. v'The length of aluminum ferrule 6 is predetermined in order to insure thatthe detonator 2 is completely, iilled with the various components placed therein.
The assembled detonator is positioned in aluminum tube 13 suchA thatthe end containing-charge 1 is' about '/s1inch ,fromonmend of they about 41/2 inches long tube 13 havingan outside` diameter `of-about 0.27 inch. An annular ring 14 isjformedv in the tube wall to ksecure the assembled-detonator inplace. Firingv pin 15 is positioned about 1A; inch from primer cup 10 and two or more indentations 16. are formed inthe tube wall to lock the tiring pin in place. Annular ring 17 is formed in the tube wall to be used later by the operator to predetermine the proper distance to whichV detonating fuse 18 should be inserted.
In operation, one length of detonating fuse 18 is inserted until the end thereof abuts against annular ring 17 and annular crimp26` is formed in the wall to secure detonating fuse 18 within the assembly. A second length of detonating fuse 19 is inserted in the other end of tube 13 and in contact with the base of case 2. Annular ring 20 is formed in the Wall of tube 13 to secure fuse 19 in position. Upon detonation of the fuse 18 gases accumulate in the space 21 behind tiring pin 15 and when suiii y cient pressure has been developed to break the lock provided by indentations 16, firing pin 15 is driven into primer vcup 10, compressing priming mix 11 between anvil 12 and the wallV of primer cup 10. Delay mix 5 is thus ignited and after the predetermined time interval afforded thereby, in this particular embodiment about 0.05 second, the explosive charges 4, 3 and 1 are initiated with subsequent initiation of detonating Afuse 19.
In the embodimentshown in Figure2 a tube 13 similar to that in the embodiment of Figure 1 is provided with a firing pin 15 secured in place by means of indentations 16 in the Wall of the tube 13. Spacedabout 1A; inch from the striking point of firing pin.15-is aconventional centerfire primer such as used in rie and pistol cartridges and designated generallyk in` the drawing` as numeral 80. Primer 80 is composed vof primer cup 100v containing primingmix 111 and anvil `121which rests against the end of ferrule 6. Primer assembly Sil-and ferrule 6 are shown enclosed in Adetonator case 2. Annular indentations 14 secure the assembled detonator in place in tube 13.- Priming mix 111 may be any suitable priming mix used in rifle and pistol cartridges.
In the rimire type embodiment illustrated inFigure 3, tube 13 contains a properly positioned ring pin 252 having an annular protuberancev 24 designed to be driven against the rimre cap 200 containing priming mix 211. Cap 200 may be provided with an annular ange similar to that utilized in` rimire rifle and pistol cartridges as an extraction ange and this ilange may extend over the mouth of detonator 2 in order to aid in water-proofing the detonator assembly. Themouth of cap 200 is butted against the open end of ferrule 6 and the 4entire assembly within detonator case 2 is such that cap 200 is rigidly supported in order to insure that priming mix 211 will be initiated when struck by firing pin 252.
In Vthe embodiment of Figure 4 illustrating a primer of the stab-initiated type, a detonator case 2 is charged with a base charge of suitable explosives such as cyclonite 1, and an initiating rcharge of lead azide 3, a delay composition Sand a primer 311. This explosive train is enclosed withinY detonator case 2 by placing a suitable washr 2 2,
. such as one cut from aluminum foil, in the mouth of case 2 and thereafter turning the end of the case 2.ove11fthev washer 22 to secure it in place. Slidable firing pin 15 is provided with a pointed protuberance 23 and is properly positioned in tube 13 by means of crimp 16. The gases developed by the detonation of the length of detonating fuse back of the firing pin 15 drive the ring pin into contact with detonator case 2 forcing protuberance 23 into mouth 27 of case 2 and through washer 22 into primer 311. The primer is initiated by the penetration.- of protuberance 23 and ignites delay mix 5 which in turn ignites the initiator charge 3 and base chargevl.'` In some embodiments of this type, a ferrule 6, such as illustrated in Figure l, may be placed between theA primer- 311V and delay mix 5. Washer 22 can be made from other metal foils such as lead or from paper, plastics or other suitable materials.
In the foregoing embodiment, priming mix 11 is about 9/10 grain of a mixture of aboutz35% potassiumchlorate, 17% lead sulfocyanate, 30% antimonysulde, k15%fcal-V cium silicide and 3% trinitrotoluene. together withI about 1/10% gum tragacanth or other suitable binder.- Theparticular composition of the priming in the various embodi-r ments is not critical, however, and conventional priming compositions containing potassium chlorate or other -suit. able oxidizer such as, for example, potassium nitrate,v barium nitrate, lead peroxide, and the like, with suitablel explosives, such as, lead styphnate, lead azide, tetrazene and the like can be utilized. Particles of glass orother equivalent abrasive material should be used inrimre primers of the type illustrated. as 211. Fuels y,Suchaspowdered aluminum and the 7like, can be substituted for all or part kor' the antimony sulfidev and.A calcium silicide In fact, any standard percussion` type .primer-suitable-fory igniting the propellant in conventional cartridgesfonshotguns or other small arms, orin stab-initiated-detonators,
is suitable. A primer containing normalr-and-sbasic leadV l styphnate, aluminum, antimonysulde and'barium nitrate is an example of a suitable primer,for..the.embodiment illustrated in Figure 4.
The embodiments of Figures 2,v 3 and z4..are,-of.course, assembled with lengths of detonatingtfusewin:thesame manner .as the embodiment of Figure 1.
Various yother well known explosives-.maybe :substituted for the explosive charges 1, 3: and'4 shownl inthe. foregoing embodiments. For example, mercury fulminate, mixtures of mercury fulminate and potassium'fchlorate,y diazodinitrophenol, tetryl, nitromannite and the -likemay be utilized in some embodiments alone'onin vmixtures thereof. Indeed, it is contemplated-that charges 1, 3A .and 4 may be replaced with a single charge'of an exploL sive such as tetryl, cyclonite, nitromannite or trinitrotolueneor the like in some embodiments of thev invention. The weight of the various explosive charges is not-critical, but it is preferred, that the assembly be at least equivalent in strength to a standard ,Bureau of Mines No.- f 6 detonator having a charge of one gram of.a,90-l0 mixture of mercury fulminate and potassium chlorate. but good results can be obtainedif the assembly has a greater power than that of the Bureau of AMines detonator.
`Other suitable delaypowders maybesubstitutedfforv dely composition 5 and the amount-used. willl vary-y withv the time interval required. -In most instances, however, a delay of from about 0.03 to about 0.05 second willbe. required in practice. magnesium, barium peroxide and selenium, barium permanganate and antimony, or charges of black powder and the like may be utilized. 4In fact, many other knowngas-producing compositions are suitable for the'purpose. f
Moreover, some delay betweenV the detonationy of the lengths of fuse willbe obtainedfrom the assembly ,even if no delay mix or detonating charge is included so suchy a device is within they purview of this invention.l In,thi s type of device not containing a delay mixhe intervalMA betr/Sea detonatitms,sependem @months .,lfziigtltf.the..7
A blendof bariumiperoxide .and-
space between the firing pin, the depth of the crimp holding the ring pin in place and the distance between the primer and the detonating fuse.
It is essential, for best results, that some space be provided between the closed end of the lring pin and the detonating fuse. It has been found that, in the absence lof such space, `often no delay will be achieved between the ignition of the rst length of detonating fuse and the ignition of the second length thereof. This space may be provided as shown in Figure 1 or the length of the firing pin may be suflcient to extend to the fuse. In `the latter embodiment, the required space is provided within the firing pin. It is also necessary, for best results, that space be provided between the point of the tiring pin and the primer assembly in order lto insure that the tiring pin will strike the cap with sulcient force to properly initiate the priming composition. `In embodiments adaptable for coupling commercially available detonating fuse having a diameter of from about 0.2 to 0.225 inch, it is preferred that the outside diameter of the tube 13 be about 0.267 inch and that the thickness of the sidewalls of tube 13 be about 0.017 inch. As stated above such a tube can be conveniently about 4.5 inches long, although tubes of other dimensions can be utilized. In such a tube, space Z1 may be about one inch, space 25 about 1/8 inch and `annular ring 17 may be located 1%,- inch from the end of tube 13. Tube 13 may be made of any material adapted to have indentations formed in the wall thereof. For example, it may be made of aluminum, copper, copperzinc alloys, synthetic resins, waterproofed paperboard or laminated paper or other similar materials.
The device provided by this invention is suitable for use with various types of detonating fuse. It has been found most advantageous, however, for use with detonating fuse similar to that known to the trade as Primacord. Such a detonating fuse has Ia core of high velocity explosive, usually pentaerythritol tetranitrate, enclosed in an outer case of fabric or metal which may or may not be coated with a waterproofing material Such as a nitrocellulose base lacquer. Such a fuse may detonate at a velocity in the neighborhood of 20,000 feet per second.
Itis to be understood, of course, that although it is preferred for convenience and ease of assembly topress the explosive charge, delay composition and percussion type igniter in a detonator case Such as described in detail above, it is possible to position them in tube 13 without use of the detonator case, provided the charges are properly pressed therein and, consequently, such a construction is contemplated by this invention. In some instances, the ange at the mouth end of a conventional shotshell battery cup may be too large to lit properly in the detonator case. Under Such conditions, it will be necessary to clip or otherwise trim the ange to the proper diameter to form a snug fit within the detonator case 2. It is also conceivable that ferr ule 6 may be eliminated entirely and that the percussion type igniter can be properly positioned in tube 13 or in the mouth of detonator 2 by other means such as by forming an annular groove in the wall of detonator case 2 at a predetermined location such that the base of battery cup 9 will rest against it when properly located in the mouth of case 2. Although it is preferred, for the convenience of the user of the device, to include means for stopping the fuse before it contacts the ring pin, the ring 17 or other means for stopping the fuse may be omitted from some embodiments provided care is taken by the operator to insert the fuse to the proper depth.
Many other variations in details of assembly may be made by those skilled in the art without departing from the spirit of this invention except as limited by the appended claims. While use of this device is primarily advantageous in commercial blasting operations it is to be understood that it may be used in any type of operation wherein two or more lengths of detonating fuse are to be initiated successively after predetermined delay periods.
What is claimed is.
1. A device for joining a i'irst length of detonating fuse to a second length of detonating fuse in end-to-end relationship and for retarding the initiation of the second length of fuse a predetermined time interval after detonation of the first length of fuse, Said device comprising a tube adapted to be slipped over the adjacent ends of the rst and second lengths of the detonating fuse, a tiring pin slidably mounted in said tube adjacent the end of the first length of detonating fuse, an explosion retarding element within the tube having a primer positioned between the tiring pin and the second length of fuse and spaced from the tiring pin, a delay composition in the tube in a position to be activated by the primer and a detonating charge interposed between said delay compostion and the end of the second fuse, and means for confining the gases developed by the iirst length of fuse behind Said ring pin and for preventing movement of said pin at less than pressure suicient for driving the ring pin into Said primer with an initiating force.
2. The device of claim 1 wherein said primer is a percussion cap.
3. The device of claim 1 wherein said primer is stab initiated.
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|U.S. Classification||102/204, 102/275.2|
|International Classification||F42D1/06, F42D1/00|