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Publication numberUS927968 A
Publication typeGrant
Publication dateJul 13, 1909
Filing dateFeb 4, 1908
Priority dateFeb 4, 1908
Publication numberUS 927968 A, US 927968A, US-A-927968, US927968 A, US927968A
InventorsJean Harle
Original AssigneeJean Harle
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Fuse with double action.
US 927968 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)



Specification. of Letters Patent.

Patented July 13,1909.

Application filed February 4, 1908. Serial No. 414,281.

To zZZwhom it may concern:

Be 1t known that I, J EAN HARL, a citizen of the French Republic, and resident of Rouen, France, havev invented new and use? fuses charged with black powder, the speed of combustlon of which does not exceed several centimenters per second slow fuses Bicki ford. 2.-The quick fuses also charged with black powder, but having a speed of combustion attaining several hundreds ofmeters per second (instantaneous fuses Bickford. 3.--The detonating tubes which are charged with anA explosive, the detonating speed of which attains several kilometers per second.

' It is evident that a detonating tube or fuse, which according to the manner in which it is ignited, belongs either to the rst category or to the third one, that is to say, which, at will, can consume slowly and serve as a fuse, or detonate instantaneously and serve as detonating tube, would render great services, particularly for military purposes, where it 1s important to reduce the number of fuses in service. There have already been made numerous trials in this respect, all experiments having however been directed to the search of a special explosive, adapted to consume slowly or to detonate, according to' how it is ignited. There have been produced particularly tubes filled with fulminate of mercury but these experiments have never given a satisfactory result. The fuses obtained either consume too quickly or too irregularly; further, they are too sensitive with regard to mechanical actions, so that their use necessitates precautions which are inadmissible for practical use. Onehas tried to diminish the sensitiveness of thefulminate of mercury by phlegmatizing the same, but then the fuses can act only as detonating tubes, belonging to the third category. Further, the experiments made for chlorated ex losives have not given satisfactory resu ts.

The object of the present invention .is a fuse at double action, which entirely fulfils all the practical requirements. This fuse 1s characterized by the fact that instead of being filled with a single explosive, it coiitains two explosive charges, one of which, the gunpowder, insures slow action, while the other, which is an explosive, secures the instantaneous detonation. In principle there are juxtaposed a fuse of the first category and a detonating tube of the third category; but the difficulty consisted in securing the regularity and the security of the two modes of operation, without increasing the diameter of the fuse over the usual diameter of fuses and detonating tubes, sa 5 mm., 5 maximum; on the other han there had to be avoided any reaction of the one explosive upon the other and particularly to be prevented that theheat, produced by the combustion of the gun-powder, provoked the detonation of the explosive.

The fuse accordingl to the present invention fulfils all th'esccondit-ions; it is represented, by way of example, in the accompanying' drawings. t

Figure l is a longitudinal section through the fuse; Fig. 2 isga cross section through the same; l4`igs.v3 tb (i represent how, with this fuse, branchings ofi' and priming can be effected. Fig. 7 is a vertical section of Fig. G and Fig. 8 represents in 'longitudinal section a double clamp. 4

This fuse essentially consists of a detonat= ing tube which forms the central core and is composed of a lead-sheath a and a filling b as trinitrotolucne, trinitrobenzene, trinitrophenic acid etc. To insure the operation of such a fuse, the explosive core must have a diameter of at least l mm. and the sheath must be without fissures. .This detonating tube is extremely fiexible, like a wire, and, for obtaining the novel fuse, it is only necessary to replace the central Wire which is frequently used .in the manufacture ofthe slow Bickford fuses, by the said detonating tube. Vith some care, the gun-powder o is easily drawn alon'g with said central detonating tube and forms a regular layer between said tube and the outer plaited sheath d, and there can be made fuses a hundred meters long without provoking -a rupture of the' tube a. The fuse thus obtained looks exactly like the ordinary fuses, but contains an explosive central core b and an annular layer c' of gun-powder, the two exploslves being separated the one from the other by the lead tube a. v

This fuse is of great flexibility and 'at the same time of great resistance. The detonating tube a is protected by the plaited cover'd and by the layer of powder c so that -it =is elim-,tively protected against accidents during its manipulation and transport. Its operativeness is always assured. As regards the slow fuse proper, it does not greatly di tler from the ordinary Biektord fuses, and

its action is in every pointsimilar to the action of said fuses.

'lhe security of these fuses at double action is absolute; the detonation cannot be eifel-ted by violent shocks or blows through emu-getic friction, nor through infiammation. 'ihe dangers are not greater than-those of an ordinary lickiord Jf'use containing nothing but black powder.

lt is to be understood that the central core l) ean belinade from different explosives; the one which has given the best results is a. tube lilled with trinitrotuluene, the leadsheath a, of which had 2 mm. of diameter. The finished fuse was of a diameter of 5 nim. and weighed 40 gr. per meter. The speed ot combustion through simple ignition was ot' about one centimeter per second. The fuse burned regularly and the trinitrotoluene burned without influencing the combustion of the black powder. rlhe detonating speed obtained by exciting the tube by means of a detonator of fulininate of mercury, was 4400 meters per second. One has detonated tubes which were longer than 100 meters, without.

any interruption of detonation and there has not, been ,traced any residue of the black powder, said gun powder being completely destroyed through the detonation of the t r nitrotoluene.

W'ith this fuse at double action branchinffs oli' can be made by simply tying each branchfuse against the main-fuse after the branchA lfuse has been provided with a detonator of fulminate 'of mercury.

Fig. 3 re resents a main-fuse e to Which, by means o a thread f, the end of a branchfuse c is tied which previously has been provided with a detonator g. i

Figs. 4 and 45 represent a s ecial joint which permits to dispense with tlie thread f. r1 his joint is made from sheet iron and consists of a clamping late h which has a spring like action an which receives rst the main fuse e whereu on the detonator e fixed at the end of the ranch fuse e1 is ns'erted in one end of the plate. The detonator g is securely pressed against the fuse a through the spring like action of clamp h. To obtain several branchings otf, from the same point of the main fuse, this main fuso is cut oit' at this point, as shown in Figs. G and 7, its end is covered with a detonator z' and several detonators 11, g2, g3, g4 are tied against said detonator z' each of which covers the end of a branch fuse el, e2, e3, e4.'

Finally, to facilitate the initial priming of a fuse according to the present invention, with the View of detonating the same, a double clamp is used, such as shown in Fig. 8, whichis composed of a central part L, the inner diameter of which is equal to the outer diameter of the primers of fulminate of mercury, while at each ot' its end this central part is prolongated by thecurved prolongations Z which are kept open through their elasticity, but can be closed by means of the rings m. If this apparatus is to be used, the end of the fuse ois covered with a detonator 'n which is inserted to about the middle of part 71.; then the ring m is moved so that the fuse is securely maintained in its position; the primer p, which covers the end of the fuse Q serving as primer, is then insei-ted into part It from the other end until it touches the detonator a. Fuse g is then secured in its position by the corresponding ring lm, bein moved. Under these conditions, whcn Iuse g is ignited which acts as slow fuse, it Will provoke the detonation of fuse o acting as detonating tube. (.)ne has to be careful, that the arms l of the clamp be short enough so that they only come in contact with the metal sheath of the detonators and not with the fuses o andl This prim-- ing arrangement can be exposed for a very long time to any weather without losing its operativeness. In certain cases, the detonator n can even bedispensed with and the fuse o can be directly placed against the detlonator n.

Referenced by
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US2511005 *Sep 28, 1945Jun 13, 1950Pool John EMine clearing snake
US2617326 *Jul 8, 1944Nov 11, 1952Ici LtdExplosive primer
US2736263 *Apr 17, 1951Feb 28, 1956 Blasting explosive device
US3021785 *May 4, 1959Feb 20, 1962Dow Chemical CoCounterforce initiation
US3116690 *Jul 14, 1960Jan 7, 1964Jet Res Ct IncFluid sensitive detonator assembly
US3945322 *Apr 5, 1974Mar 23, 1976The United States Of America As Represented By The Secretary Of The NavyThrough-bulkhead explosion initiation
US3987732 *Feb 10, 1975Oct 26, 1976The Ensign-Bickford CompanyNon-electric double delay borehole downline unit for blasting operations
US3987733 *Feb 10, 1975Oct 26, 1976The Ensign-Bickford CompanyMillisecond delay surface connector
US4314508 *Feb 22, 1979Feb 9, 1982Ici Australia LimitedDevice with incendiary fusecord ignited by detonation
US4917017 *May 27, 1988Apr 17, 1990Atlas Powder CompanyMulti-strand ignition systems
US5001981 *Apr 16, 1990Mar 26, 1991The Ensign-Bickford CompanySignal transmission tube for initiation of explosives
US5086702 *Feb 20, 1991Feb 11, 1992Atlas Powder CompanyModular blasting system
US5162606 *Nov 8, 1991Nov 10, 1992Atlas Powder CompanyModular blasting system
US5204492 *Oct 30, 1991Apr 20, 1993Ici Explosives Usa Inc.Low noise, low shrapnel detonator assembly for initiating signal transmission lines
US5665932 *Dec 14, 1993Sep 9, 1997Aeci Explosives LimitedInitiation of blasting
US6123025 *Dec 1, 1992Sep 26, 2000Orica Explosives Technology Pty Ltd.Low noise, low shrapnel detonator assembly for initiating signal transmission lines
US6688231 *Jul 26, 2000Feb 10, 2004Autoliv Development AbCord-type gas generator
US8267012Dec 6, 2005Sep 18, 2012Dynaenergetics Gmbh & Co. KgReliable propagation of ignition in perforation systems
US20100024674 *Dec 6, 2005Feb 4, 2010Roland PeetersReliable propagation of ignition in perforation systems
WO2002084204A1 *Feb 8, 2002Oct 24, 2002Appleby Rodney WExplosive cutting device
WO2006063713A1 *Dec 6, 2005Jun 22, 2006Dynaenergetics Gmbh & Co KgReliable propagation of ignition in perforation systems
International ClassificationF42D1/04
Cooperative ClassificationF42D1/043
European ClassificationF42D1/04F