July 22, 1947. J, TAYLOR TAL 2,424,374 BOOSTER Filed May 20, 1943

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Patented July 22, 1947 2,424,374

UNITED STATES PATENT OFFICE 2,424,374 EPOSIVE BOOSTER, James Taylor, Saltcoats, and Harold Reginald Wright, West Kilbride, Scotland, assignors to imperial Chemical Industries Limited, a cor poration of Great Britain Application May 20, 1943, Serial No. 487,764 In Great Britain July 29, 1942 8 Clains. (C. 102-27) 2 The present invention relates to improvements the intermediate explosive booster to be attached in the manufacture of intermediate explosive in detonation contact with the explosive charge boosters and to the new or improved explosive which it is required to detonate in the case of boosters thereby obtained, and more particularly ammunition of certain kinds, but in the case of to intermediate explosive boosters in which an explosive charges for demolition and the like pur explosive charge is cast into a tubular container. poses it is frequently more convenient that the By an intermediate explosive booster we nean attachment of the intermediate explosive booster a booster that comprises a detonating explosive to the explosive that it is required to detonate charge and is adapted to be assembled with a should be deferred until a late stage, for instance Or detonating , optionally having O until the operator is about to place the explosive a booster cap attached thereto, or to the like into position. In any case, the attachment of detonating components of the blasting assembly, the detonator Or detonating fuze, whether or not for the purpose of transmitting an enhanced provided with a booster cap, is delayed as long detonating impulse to an explosive charge in ef as possible, and for demolition purposes is there fective detonation contact with the booster ex fore carried out at the locus where the blast is plosive. Intermediate explosive boosters are use to take place during the laying of the shot. ful in demolition and blasting operations, and In military operations it frequently happens in the assembly of nines or the like, for military that the time available for manipulation at the or other purposes where it is required to bring locus where the detonation is desired to take place about the detonation of an explosive charge from 20 is very limited, and such manipulation may re a distant point, especially when this explosive quire to be carried out in a position exposing the charge is insufficiently sensitive to be initiated operator to unusual danger from the enemy, and with certainty by means of a detonator, detonat in such circumstances it may be inevitable that ing fuze or the like attached to it directly at the the materials required to complete the blasting time the component parts of the blasting assen assembly will be roughly and hastily handled, so bly are put together. that failure of the shot due to insufficiently close As the explosive for the intermediate booster juxtaposition of the components is not unlikely. . there is frequently employed a pellet of con The erroneous employment of or pressed or compressed guncotton, but for booster caps of a diameter slightly greater than convenience or cost in manufacture of the inter SO the proper diameter but capable of partial inser mediate explosive booster it would often be desir tion into the primer may result in failure due to able to employ a charge of an explosive adapted the same cause. It is an object of the invention to solidify as it cools to ordinary temperature, to provide an intermediate booster containing a cast in fluid condition at raised temperature into cast explosive charge of greater certainty in a container. action in such circumstances, As such a charge there may be used, for in According to the present invention there is per stance, molten mixtures of trinitrotoluol and manently positioned in the intermediate explosive tetry, or pentaerythritol-tetranitrate, or par booster in effective detonation contact with the tially molten mixtures of trinitrotoluol with pen cast explosive charge between the latter and the taerythritol tetranitrate or cyclo-trimethylene 40 detonator, detonating fuze, or like component of trinitrainine, and in the specification of the U. S. the blasting assembly to be inserted into the application of James Taylor rumbered 424,947, booster, a smaller charge of compressed explosive a form of intermediate booster containing a cast that is substantially more sensitive to initiation explosive charge intended for assembly with a by the impulse of a detonation than the cast detonator is described. Cast explosive booster 45 booster explosive but is insensitive to initiation charges are, however, somewhat less sensitive to by fame. The smaller charge of the more sen initiation than compressed tetryl or compressed sitive explosive may consist of compressed penta guncotton charges, and while boosters containing erythritol tetranitrate, compressed cyclo-tri cast explosive charges function satisfactorily methylene-trinitramine, or other compressed ex when the detonator, detonating fuze or the like plosive of similar sensitiveness to initiation by a is brought into close juxtaposition with the cast detonating impulse. booster charge, the cast booster charge may fail In putting the invention into effect, the portion to detonate if in the assembly they are not of the tubular booster casing intended to receive brought close together. the detonator, detonating fuze, or the like is of n transport and storage it is most usual for 55 smaller internal diameter than the remainder,

2,424,374 3 4. and the compressed explosive charge is contained and 4 have the same significance as in Fig. 1. In in a tube of which either the open end or the this form of booster the tube 6 containing the - closed base protrudes into this portion, and is compressed charge 3 compressed into it is first attached, if desired with the assistance of a ce cemented into the tube 7, and the charge 4 is ment close up to the cast primer explosive poured then cast around the tube 6 and into its open end. into the larger portion of the booster tube. The The fuze illustrated in Fig. 2 may consist of attachment of the detonator, detonating fuze Or cordeau detonant or the like, or textile detonating the like within the portion of the booster adapted fuze. In the former case the envelope 3 is of a to receive it may be provided by means of a metallic nature, and the core 4 consists of tri crimped joint or by spring pressure, for instance, 10 nitrotoluol; in the latter case the envelope 3 by the provision of longitudinal slots and pro consists of textile coverings and the core 4 may tuberances in the narrow part of the booster cas consist, for instance, of pentaerythritol-tetrani ing, over which a movable collar is adapted to ride trate. on to the protuberances to exert a gripping pres The capped fuze illustrated in Fig. 4 may either Sure. The tubular booster casing is preferably 15 be a detonating fuze capped with a booster cap or Open at both ends, and may be made of any con a safety fuze capped with a detonator. In the venient material. If desired the portion of larger former case the envelope 7 and the core 8 may A diameter may be provided with an internal or ex be as described in Fig. 2 and the charge is within ternal cannelure or the like to assist in the re the tube 5 may consist of compressed pentaeryth tention of the Solidified cast charge in it or to 20 ritol tetranitrate or tetryl. In the latter case aSSist its own retention in the explosive charge the envelope 7 comprises textile coverings and of which it is intended to bring about the detona the core 8 is of ordinary fuze powder and the tion. The tube containing the compressed ex filling 9 of the tube 5 comprises a charge of a plosive charge may, if desired, be wholly closed composition sensitive to detonation when ignited at one end, or may be provided with a pin hole at 25 by the flame from the fuze powder. The charged its closed end. This tube may also be made of tube or detonator tube is crimped to the fuze at 6. any convenient material, and if both tubes are In Fig. 5 the parts ?, 2, 3, 4, 13 and 4 have the made of metal, the materials are preferably the Same significance as in Figs. 1 and 2, the assem- A Same or such that one of them does not appre bly being made by crimping the booster over the Ciably increase the tendency to corrosion of the 30 detonating fuze as shown at 20; an air space due other in the presence of moisture. The tube con to imperfect juxtaposition is shown at 2. In taining the compressed explosive charge may be Spite of this air space, the booster functions provided with a circumferential ridge, enlarge satisfactorily. ment or the like to assist its retention at the in If in the assembly of the detonating fuze illus ternal shoulder between the broad and narrow 35 trated in Fig. 2 or the capped fuze illustrated in portions of the booster tube, which is desirably Fig. 4, with the booster illustrated in Fig. 3 the assisted by the employment of a cement. juxtaposition of the components is imperfect, so The invention is further illustrated in the ac that a Space is left between the end of the deto companying drawings, of which Fig. 1 represents nating fuze or the end of the tube 5 and the One form of booster made in accordance with the 40 closed end of the tube 6, the booster will never invention specially adapted for assembly with theless detonate satisfactorily. detonating fuze. Fig. 3 represents anotherform We claim: of booster made in accordance with the invention 1. An explosive booster comprising a tubular adapted for assembly with a detonating fuze, Or casing Open at both ends of narrower diameter with a detonator. Fig. 2 represents a piece of at One end than at the other, said narrower end. detonating fuze without a booster cap and Fig. 4 45 being adapted to receive a detonating component, represents a Capped fuze either of which can be : a tube of Smaller diameter than said casing closed used with the booster shown in Fig. 3. Fig. 5 at one end, located within the casing, sealing off represents the booster shown in Fig. 1 crimped the narrower portion of the casing from the wider over the detonating fuze shown in Fig. 3, in in 50, portion, a flame-insensitive detonating explosive perfect juxtaposition. charge compressed within said tube into contact In Fig. 1, is the casing of the booster open with the closed end thereof, and a second flame at both ends, 2 is a tube closed at one end, namely, insensitive detonating explosive charge, larger in the right hand and as shewn in the figure, 3 is quantity than Said compressed charge, cast with the charge of the more sensitive explosive. In in the wider portion of said casing in direct con this form of booster the charge 4 may be cast tact with said tube and said compressed charge, around a mandrel first inserted in place of the Said compressed charge being substantially more tube 2, which is withdrawn when the charge 4 sensitive to initiation than said cast charge. has solidified. The tube 2 containing the charge 3 2. An explosive booster comprising a tubular pressed into it is then cemented into position by 60 casing Open at both ends of narrower diameter means of a polyvinyl acetate cement 5. Alter at One end than at the other, said narrower end natively the charge 4 may be cast into the casing being adapted to receive a detonating component after the tube 2 loaded with the charge 3 has and to retain said component after insertion by been cemented into its position in the tube . deformation of the casing about said component, In Fig. 3, 7 is the casing of the booster open at 65 a tube of Smaller diameter than said casing closed both ends, 6 is the body of a tube closed at one at One end located within the casing with the end, namely, the left hand end as shewn in the Open end of the tube protruding into the wider figure, and 5 is a layer of polyvinyl acetate ce portion of the casing, the closed end of the tube ment by which the closed end of the tube 6 is Sealing off the narrower portion of the casing attached to the body of the booster 7, 8 is one 70 from the wider portion, a flame-insensitive deto of two slots with enlarged terminal portions 9 nating explosive charge compressed within said in the body of the tube 7, and 0 and i? are pro tube into contact with the closed end thereof, tuberances pressed into the body of the tube 7. and a Second flame-insensitive detonating explo f2 is a movable collar adapted to ride up on to Sive charge, larger in quantity than said com the protuberances O and ff. The numbers. 3 s pressed charge, cast within the wider portion of

2,424,374 said casing in direct contact with said tube and 8. An explosive booster as claimed in claim 1 the free surface of the compressed charge, said wherein the compressed explosive is compressed compressed charge being substantially more sen cyclotrimethylene-trinitramine. sitive to initiation than said cast charge. 3. An explosive booster as claimed in claim 2 JAMES TAYLOR. wherein the portion of the Casing adapted to re HAROLD R. WRIGHT. ceive the component of the blasting assembly is slotted and protuberanced and provided with a REFERENCES CTED movable external collar capable of contracting said portion for the purpose of exerting gripping 10 The following references are of record in the pressure on said component. fle of this patent: 4. An explosive booster as claimed in claim 1 UNITED STATES PATENTS wherein the cast explosive charge Comprises a Number Nane Date solidified molten mixture of trinitrotoluol and 1906,869 Noddin ------May 2, 1933 tetryl. 900,670 Daniels ------Oct. 6, 1908 5. An explosive booster as claimed in claim 1 1,599,078 Corrie ------Sept. 7, 1926 wherein the cast explosive charge consists of a 356,064 France ------Jan. 11, 1887 solidified at least partially molten mixture of trinitrotoluol and pentaerythritol-tetranitrate. 1783,372 Woodbury ------Dec. 2, 1930 6. An explosive booster as claimed in claim 1 FOREIGN PATENTS wherein the cast explosive charge consists of a Number Country Date solidified partially molten mixture of trinitrotoluol 16,919 Great Britain ------1887 and cyclotrimethylene-trinitrainine. 145,791 Great Britain ------Mar. 17, 1921 7. An explosive booster as claimed in claim 1 512,083 France ------Oct. 4, 1920 wherein the compressed explosive is compressed pentaerythritol-tetranitrate.