US2754756A - Detonator holder - Google Patents

Description

B. F. DUESING DETONATOR HOLDER July 17, 1956 /A//Eh/Toef 5527' E 0055/ y Ar Filed Feb. 26, 1951 United rates The present invention relates generally to blasting accessories, and more particularly to a detonator holder for use with a blasting cartridge.

Briefly, the invention comprises a novel device to be disposed within a standard blasting cartridge for insertion of a detonator thereinto. The device may be constructed in a variety of species, three of which are shown in the accompanying drawing. Each species includes means for disposing a detonator in predetermined position for efficient detonation of a primer charge, means for resisting the entry of foreign liquids into the primer charge, and, where electric detonators are used, means by which static electricity may be conducted for grounding the detonator'.

Geophysical prospecting for minerals with the seismograph has become increasingly widespread during the past several years. In this type of geophysical activity, a basic aim of the prospector is to set off an explosion or seismic blast at a predetermined location either above or below the surface of the earth and to receive a record of the disturbance on a seismograph. With foreknowledge of the location and the approximate force of the blast, the prospector is able to interpret the recorded effect of the blast in terms of geologic structure.

In the conduct of this type of geologic exploration where the blasts are set olf below the earths surface, it has been found most practical to drill and charge a number of holes in an area to be investigated before exploding any of the individual charges. Thus, many of the explosive charges must sleep for a period which may extend for days or even Weeks. It is then not uncommon for the charge 'to fail to explode properly due to poor detonation of the primer charge. Poor detonation may result from several causes, one being faulty positioning ofthe detonator within the charge.

It is, therefore, an object of the present invention to provide a detonator holder which is relatively easily inserted in a standard blasting cartridge and which, when thus inserted, is adapted to dispose a detonator in position for efficient detonation of a primer charge.

Another cause contributing to poor detonation, particularly with respect to sleeper charges, is deterioration of the primer charge itself due to the entrance of water. It has been normal practice in the past to punch a hole inthe cartridge cover and make a cavity in the charge for insertion of a detonator therein. Obviously, such a procedure affords a ready means for water to enter the cavity and to soak the dope which constitutes the primer charge in the area around the detonator.

It is another object of the present invention, therefore, to provide a detonator holder which may be inserted into anl explosive cartridge in a manner to resist the entry of water into the primer charge.

Static electricity, particularly in arid regions, and electrical storms have caused a number of premature explosions of blasting charges where electric detonators have been used. The obvious danger to personnel, as well as the expense involved through the loss of the charge and atent at least part of the shot hole where the charge is soV emplaced, makes mandatory the adoption of correctiveA procedures. Losses of this type can be substantially eliminated by grounding the metal case of an electric detonator so that static electricity may be drained off as it accumulates.

It is another object of the present invention, therefore, to provide a detonator holder which is adapted to conduct static electricity for the purpose of grounding an electric detonator.

Other objects and advantages will be obvious from the following description taken with the accompanying drawing, in which:

Fig. 1 is an end view of a detonator holder constructed in accordance with the teachings of the present invention;

Fig. 2 is a side elevation, partly in section, thereof;

Fig. 3 is a side elevation of a detonator holder with an attached grounding wire, the detonator holder being inserted in an explosive cartridge, shown fragmentarily in section;

Fig. 4 is a top view of a detonator holder with shield;

Fig. 5 is a side elevation of the detonator holder of Fig. 4;

Fig. 6 is a sectional elevation of the detonator holder of Fig. 4 inserted in an explosive cartridge, shown fragmentarily;

Fig. 7 is a top view of a modied detonator holder with cup;

Fig. 8 is a bottom view of the detonator holder of Fig. 7; and

Fig. 9 is a sectional elevation of the detonator holder of Fig. 7 inserted in an explosive cartridge, shown fragmentarily.

Referring to the drawing more particularly by means of reference numerals, a very simple embodiment of the invention is shown as 10 in Figs. l, 2 and 3. Here, the detonator holder 10 comprises a tube 12 having a diagonally tapered end 14 and an intermediate restricted portion 16. The tube 12 may be of any appropriate material, such as paper, glass, rubber, plastic, or any suitable metal, the latter being preferable where electric detonators are to be accommodated. The restricted portion 16 serves to divide the interior of the tube 12 into a primer section 18 and a detonator chamber 20. An end 22 of the tube may be plain as shown in Fig. 2, or it may be formed to any of a variety of suitable shapes, such as to provide an angular cut-olf, a ange, a funnel, etc. For use with electric detonators, the detonator holder 10 may have an attached ground wire 24 as shown in Fig. 3.

Another embodiment of the present invention is shown in Figs. 4, 5, and 6, wherein a detonator holder unit 26 comprises a detonator holder 10 having an attached shield 28 adapted to fit the outside of a blasting cartridge 30. The shield 28 thus serves as positioning means for disposing the detonator holder 10 in a predetermined position to insure efficient detonation of the primer charge. Additionally, the shield 28 may have an appropriate sealing compound applied thereto to provide a waterproof joint with the blasting cartridge 30, and may also have a grounding wire attached thereto (not shown).

Both the detonator holder lil and the unit 26 are primarily adapted for side-wall priming in which the blasting cartridge 30, comprising a container 29 and an explosive mixture 31, has a suitable detonator introduced through a side wall of the container 29. When a detonator holder, such as 10, is thus introduced as shown in Figs. 3 and 6, the diagonally tapered end 14 serves two purposes, the first being to facilitate penetration of the wall of the container 29, and the second being to insure that the detonator holder 10 is not placed in a position wherein the opening at the inner end of the tube Patented July 17, 1956- lSince the detonator holderlt) makes its own hole in Y the container 29, it-is obvious thata relatively tight joint will be effected betweenthe tube l2 and the wall ofthe container 29, thus resisting the entry of water around the outside of the tube l2. Additionally, as the tube l2 ispushedlinto the explosive mixture 3l, some of the latter enters the tube 12 and is forced therethrough until it becomes congested at the restricted portion 16, thereby forming a plug to -resist entry of Water through the rinterior ofthe-tube i2; l

After a detonator holder is in place, a detonator of the desired type may be inserted in the detonator charnber Ztl. The detonator mayV bea detonating fuse or it may'be a detonating cap for either fuse or electric ignition. Ir it is Van electric detonating cap, a tube 12, of metal to which a ground wire 24 is attached, Will provide an eicient path for the conduction of static electricity from the cap to ground. Y

'The detonatorrholder l@ and unitf26 are'obviously Well adapted for field insertion, but it is to be understood that they may equally well be inserted during the manufacture of the cartridge 3b. Regardlessof the time of inbe understood, therefore, that the foregoing description and the accempanyinadrawins bevallen@ .gil/@.11 by Way of illustration and example, It is further to be `understood that changes in the form of elements, rearrangement of parts, and substitution of equivalent elements are contemplated as Within the scope of the present invention, which is limited only by the claims which follow.

What is claimed is:

1. In combination, a blasting cartridge comprising a closed cylindrical'container containingfan explosive mixture, means for containing adetonator, said means comprising an open ended tubularmember provided vvith an internal restriction intermediate its ends, said tubular member being disposed Witliinsaid cylindrical container so that one end communicates with the outside of said cylindrical container thereby to provide for insertion of Y a detonator into said tubular member as far as said resertion, the merits of a judicious application'ofappropriate Waterprooting agents or compounds at the joints between the detonator holder l@ and the cartridge 3Q, including the` disposition of a plug of such substance in the primer section 18, will be appreciated. For field insertion, particularly, a tool suitable to cooperate Vwith an appropriately .shaped end 22 as above mentioned'can be used to facilitate placement of the detonator holder l0 or unit 26 in the cartridge 3i). i

Another form of detonator holder unit is shown as 32 in Figs.'7, 8 and 9. The detonator unit 32 comprises a tube 34, an open end of which is appropriately secured within a cup 36 as clearly shown in the drawing. The tube 34, being preferably `longer than the depth of the cup .3.6, extends therebeyond and this extended free end is closed by a disk 40 appropriately secured thereto. Alternatively, the free end of the tube 34 may be closed by the insertioxyi of a suitable plug therein. Such a plug could be formed from conventional detonating fuse, the detonating force of which would, of course, be added to that of the blasting cap. Where aV disk such as 40 is used, it may be of material 'that will shatter or rupture easily under the force of the exploding detonator so as to permit substantially the full detonating force Yto issue therefrom,

Although a detonator holder unit auch as 32 is beet adaptedto insertion in a cylindrical cartridge such as during manufacture, it may also be inserted in the eld. Foreldinsertion, apunchingtool may be used topenetrate vthe end wall of the containerf29 and `to form a suitablecavity in the explosive mixture 3l to receive'the tube 3 4, or the tube 34 may be formed toinclude either an open or closed pointed end. If an open end construction is desired, the tube 34 may yalso be formed with a restrictedsection similar to le in Figs. 1 through 6.V The striction, the other end of said tubular member, including the interior thereofas feras said restriction, being embedded in said explosive mixture, the portion ofthe explosive mixture within the tubularrnemberadjacent the restriction Vbeing Vadapted to resiisbtlie entry of Water through said tubular member into the main body of said explosive mixture. Y l

`2. The combinationof claim l wherein the tubular member isofrnetal and has properties o f electrical conduction, andzadditional electrical conducting means securedto Asaid*` member for the purpose of Vproviding an electr-ical groundconnection with respect to the tubular member and its contents. 'Y

` 3. In combinatioma blasting cartridge cgmprisinga closed cylindrical container containing `anexplosive mixture, means .for containing a detonatpr having a length greater than. the diameter of the cylindrical container, said means Vcomprising an elongated tubular member 'Vdeflning a cylindricalfchamber having-at least one openv end .and being disposed diagonally Within said ,cylindrical container so that said open end communicates With the v outside Vof said cylindrical container thereby to provide inside of the cup 36 may be pre-coated with Aa suitable Y y grounding electric dctonators as above described in respect to the detonator holder l@ and unit 26.

It is apparent that detonator holders of the general type-above described fulll the objects and advantages sought therefor. vlt is furtherapparentthat numerous 4 comoinations,and variations Vof elements and construc- :tion .will'be obvious tothose skilled in the art. It `is to for insertion of adetOnatOr'into saidcharnber through the cylindrical wall of said cylindrical container, and shielding means integral With said tubular member, said shielding `means .being shaped to cooperate with said cylindrical wallof said cylindrical container for resisting the'entry of wate'raroundthe outsideof said means for containing a detonator into said explosive mixture.` 4. ,A device for receiving a detonator througlral cylindricalwall. of a blasting cartridge which includes a tubular member disposed substantially ,Wholly within s vaid cartridge, said tubular member having a length greater than the diameter of said cartridge andbeing open at both ends, at least one end. openingbeing diagonal with respect to the axis of thetubular'm'embenthe tubular member being disposed withinV the cartridge at a diagonal to the-'axis` of the cartridge with said .diagonal operi end facing generally 'toward the axis of the.y cartridge.

5. A devicefor receiving a detonator through a. cylindrical wall of a blasting cartridge'which includes a tubular member disposed within `said cartridge, said tubular memberhaving an open end ysubstantially flush with the outsideV surfaceof said-wall, and a'shie'lding member formed to the curvaturel of'saidwall and secured to said open end of said tubular member, said shield being vadapted to cooperate with said wall to` resist` entry of Water betweensaid tubular memberand said Wall adjacent thereto.

6. A device for use with a cylindrical blasting cartridge, comprising an.v elongated tubularmember provided with internal stop means for positioning'a detonator therein, said tubular member being openv at both` ends and having one end formed diagonally with respect tolthev axisof the tubularrriember so las to facilitat e penetratinginsertion of the, same intosaid cartridge 'for,disposition'diagonally l.therevvithin,'l the other end of said tubularfineinberY being adapted to exteridfthroughi tlelcyl dricaliA Wujof said cartridge thereby to receive a detonator for disposition wholly within said cartridge.

7. The device of claim 6 wherein the internal stop means takes the form of an internal restriction located intermediate the ends of the tubular member, said restriction being adapted to impede the passage of explosive mixture forced into said one end upon insertion of the `tubular member into the cartridge.

8. The device of claim 6 wherein said other end of the tubular member is provided with a shield disposed angularly with respect to the axis of the tubular member, said shield being formed to lie ush with a cylindrical surface.

References Cited in the ile of this patent UNITED STATES PATENTS

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