US2535518A - Fuse igniting and connecting means - Google Patents

Description

Dec. 26, 1950 J. D. RICH FUSE IGNITING AND CONNECTING MEANS Filed Sept. 25, 1948 se gill.

INVENTOR. Jan Zfzff/ BY @aux QML Patented Dec. 26, 1950 UNITED STAfEEpSL FUSE'IGNITING AND CONNECTING MEANS John D. Rich, Simsbury, Conn., assignortoick ford. Research. La,boratories,` Inc., Harttord, Conn., a corporation of Connecticut Application September 25, 1948, Serial No. 51,254

4, Claims. (Cl, 102,-.-27)

This invention` relates toa fuse igniting and connecting means, principally'for use in blasting4 operations, but also usable for pyrotechnic devices, eta, which ignitively connectsan ignition cord; and ai, safetyV fuse or which; connects other devices-.in which itis desired` to convey re from onetype of ignitins means to another with, certainty under all conditionsofruse.

Incomercial blasting operations it has been common for many years to use safety fuses. ExamplesA of certain. types of safety fuse are described` in- U. S; Patents; Nos. 1,907.863. and mm2-024, both to Pearsall. More recently, the soecalled isnition: cord of the types described in U; S. Patents Nos. 2,239,051 and 2,239,052, both to Rearsall andi the present applicant jointly, has come intouse for progressivelyiigniting the safety fuses in correct rotation or= a desired sequence.

Brieiiy, safety fuse consists of continuous lengths of.= a product similar-in appearance to in.- sulatedI wire, but containing a, central powder core in place ofthe wire. The. interior core of the fuse burns ata predetermined and uniform rate- .-relati-vely slow-under various conditions ot use; andA conveys firev to thef explosive or eX- plosive device. In contra-distinction, ignition cord, while produced in continuous lengths, is characterized by burning exteriorly at a uniform and rel-tively rapid rate: its structure` consists of a central insulated wire having a powder coatingV which may ormay not befurther protected. Ignition cord is used only' to ignite safety fuse or other types of i'f'niting media.

Infcertain` mining operations, it is important to setv oifvv a plurality of blastingY charges in some regularv orv predetermined order or sequence. A method and means for doing this, using safety fuse and ignition cord, is. described in the patent to Stoneking, No. 2,239,123. In the practice of this method it is necessary that ignition or flame be transmitted froml an ignition cord as aforesaidto a safety fuse. Various arrangements have heretoforel been proposed and in some cases tried out for effecting this purpose. One of the best of such prior arrangements has been to split an end portion of the safety fuse by-a radial cut eX- tending approximately to the center thereof and extending down thelength of' ther fuse for about three-fourths an inch from. the end. This cut is then opened to some extent and ignition cord placed inv the opening; The two may then be bound together in any-su-itablp-manner as by'wire, string. tape or the like. With this type of connecton.. the methodoutlined in the Stoneking patent; mayv then be carried out as set forth in that patent. The slit joint is an effective firing joint, but is difficult to waterproof. Its preparation, consumes an excessive amount of; time. One advantage of the present invention is to provide easier, quicler and more waterproof con-V nection` means.

The reinforcing wire element within the ignition cord ena-bles4 it to retain its position when the cordV is wrapped. around another object as, imI example, another piece of ignition cord, or a supporting rock'orpost,

A primary object of the present invention is to provide connecting means for use between an., ignition cord and, a safety fuse, so as to in.- sure the desired transfer of fire or ignition from the ignition. cord; to; the safety fuse under all conditions reasonablymet with. in practice.

Another object of the present invention is to provide connecting meansl as aforesaidA and partieularly` including a tubular member of suit,- ab-le size for receiving the. adjacent ends of the ignition cord and safety fuse, which will be op.- erative under all conditions of moisture. such as are often met with at a blastingsite and which Wil-l,` be operative for the certain transmission. of ignition from one to. the other, notwithstanding such4 moisture conditions.

A furth^r object ofthe present invention is to provide a connecting device and means which will serve to holdI the ignition cord in place adiacent to each blast hole. after the associated safety fuse has been ignited, so that the ignitioncord' cannot contact and accidentally ignite unburned ignition cordcausing possible interference with a desired ordel` or sequence of blast- 'ing when a plurality of charges are to be ignited -in desired rotation or seduence.

Otherv objects and' advantages of the present invention will' appear from the following descrintion and appended claims. when considered in commotion with the accompanying drawings, in which:

Figure 1 is a view principally in transverse vertical section of a connecting means and a safety fuse Shown in elevation in their operative relation to one another, this being the preferred form in accordance with the present invention;

Fig. 2 is a similar view showing a modified formy of the present invention; and

Fig. 3 is a similar view of another modified form thereof.

Referring rst to the preferred form of the invention shown inV Fig. 1. there is illustrated a substantially cylindrical tubular member I0., which may be of plastic, cellulosic or metallic material asfmav be desired. The tubular member la; is initially formed substantially cylindrical with both ends open prior to the assembly of the connector. A metallic` sleeve Il may be suitably inserted and securcd in one end of the tubular member t0, thisV sleeve Il being provided for mechanically securing an end of'a piece ofI safety fuse t2 within the tubular member. la. As shown, the inside diameter of" the mem-5 ber I0 is just slightly larger than the outside diameter of` the safety; fuse. |24-, so that` the late ter may` be freely inserted through the sleeyev II in assembling the connector to the end of a safety fuse. a plurality of inwardly directed prongs I3 as shown for engaging the safety fuse I2 and preventing its accidental withdrawal from the tubular member I0.

One end of a length of an igniting means, as for example a short piece of ignition cord I 4, which has a substantially smaller outside diameter than the inside diameter of the member Ii?, is projected into the other end of the member II! as shown and terminates in a mass I 5 formed by gathering or twisting together portions of the ignition cord I4, `so that the mass I5 as a whole has a substantially greater diameter than that of the cord I4. cord may be doubled back and wrapped around a portion adjacent to the end thereof, the mass I5 as a whole being located closely adjacent to and in igniting proximity with the end of the safety fuse I2. It is preferred that this end of the safety fuse be cut off substantially on a plane at right angles to the length of the safety fuse. This is sometimes termed square cut, as distinguished from an oblique cut. Some part or all of the mass I5 may, if desired, be coated with a suitable ignition compound I5a of an oxygen- Ysuiiicient character, such compounds o-r compositions being well known in the art. One such compound comprises a thermit type powder carried in a nitrocellulose binder. This composition insures anV incandescent glow or flash at the place of transfer of ignition and makes certain the Vignition of the safety fuse. At the same time the thermit does not form gases which might generate sufcient pressure to burst the tubular member I0.

The ignition cord I 4 may be held in a predetermined position within the tubular member ID by any suitable mechanical means. In the preferred form shown in Fig. 1 this comprises a wire staple I6 passed through the sides of the tubular member Il), so as to colapse and compress it around the cord I4, each prong of the staple I 6 passing through two thicknesses of the tubular member I9 and being suitably crimped on the outside as is common in the art of wire stapling.

In assembling the parts, a short length of ignition cord as I4 is secured in the tubular member IIl as shown in Fig. 1 and suitably mechanically secured in position as shown. If desired, this ignition cord may be further sealed in the end of the tubular member ID by the use of a water-proofing composition, usually a wax-like material, a few drops of which may be introduced as shown at I'I prior to or at about the time of the insertion of the staple I6, so as to seal this end of the member ID against the ingress of moisture. The assembly may then be transmitted to the point of use in this condition, the short length of the ignition cord I 4 projecting as shown in the drawings serving to connect the assembly to some other length of ignition cord which may -be assembled in accordance with the teaching of the Stoneking patent aforesaid at the point of use. Y

The safety fuse after being suitably square cut as aforesaid may then be introduced into the right hand end, as seen in the drawings, of the member Il) as far as it will go, i. e. to a point such that the inner square cut end is closely adjacent to the mass I5.

In addition to the mechanical means shown at I I-I3 for holding the safety fuse I 2 in the tubular member I0, it is-usually desired that means The sleeve I I is provided withV As shown one end` of the ignitionl 4 be provided for preventing the ingress of moisture into the tubular member I@ between it and the safety fuse l2. For this purpose, an annular body of a suitable water-proong compound, usually of a wax-like nature, may be provided at the joint between these members as shown in Fig. 1 at IS. The compcsitions shown at I 'I and I3 thus constitute a sealing means for preventing ingress of moisture into the place where ignition is to be transferred as aforesaid.

In the form of the invention shown in Fig. 2, there is provided a tubular member I9, similar to the member I t, and provided with a metal sleeve member 2Q, similar to the member I I, for receiving one end of a piece of safety fuse 2|, suitable prongs or projections 22 being provided on the member 2B, corresponding structurally and functionally to the prongs I3 above described.

One difference between the forms of Figs.' 1 and 2 is in the manner of holding the ignition cord, here shown at 23, in place in the tubular member i9. A further difference resides in the manner of providing for the transmission of ignition from the inner end of the ignition cord 23 to the end of the safety fuse 2l, which is also preferably square cut as shown in the drawings.

In this instance there is provided surrounding the ignition cord 23, at a zone spaced from theV end thereof, an annular plug 24 formed of a suitab'e material such as rubben'which has an outside diameter sufficiently small to be readily insertable within the tubular member I9 as shown. Thereafter the tubular member I3 may be crimped or otherwise suitably held aro-und this plug 24. In the event Vthat the tubular member is made of metal, this crimping may be done by a suitable crimping tool operating upon the metal itself in a manner well known in the art. If, on the other hand, the member I9 be of paper of some cellulosic material, it is usually desirable to use a binding wire as sho-wn Vat 25, the wire being wound in a suitable number of turns and being twisted together in a usual manner, so as to form a groove in the tubular member le, as shown, and to bind the tubular member tightly around the plug member 24.

In this instance the transfer of ignition is provided by forming a suitable loop or U-bend 26 of the ign'tion cord and cutting an outer portion thereof away, or slashing it for about onehalf inch to expose an amount of the oxygensuffient burning composition with which the ignition cord is provided, so as to provide an incandescent glow or Rash upon the lighting of the ignition cord and the transmission of combustion to the inside point thereof shown as the loop 26. This will be sufficient to ignite the burning composition centrally of the safety fuse 2l, the end of which is located adjacent thereto as hereinabove described in c-onnection with Fig. 1.

Suitable sealing means may be provided, using a wax-like water-proofing composition as shoswn at 2l and 28 for sealing the joints between the tubular member I9 and the ignition cord 23 and safety fuse 2| respectively, all substantially as described above in connection with the Fig. 1 form of the invention.

Turning now to the form of the invention shown in Fig. 3V, there is illustrated a tubular member 2) corresponding functionally to the tubular members EG and i9 hereinabove described. In this case, however, the tubular memberfZS is preferably of metal or some relativelyrigid material, which may retain anyshape imparted to it and which can act by suitable deformation' so as mechanically to grip onto parts therewitbin. As shown, there is projected into the right hand end of the member '29 a square cut end of a piece of safety fuse 3U. C'osely adjacent to the square cut end of the fuse Within the tubular member 29, is an insert 3| consisting at least in part of oxygen-sufficient combustible material, which may be preformed as shown into a substantially cylindrical annulus. As shown, a piece of ignition cord 33 has its end portion extending centrally through the insert 3l to a point closely adjacent to the end of the fuse 30. Surrounding the ignition cord 33 outwardly from the insert 3l is a suitable annular plug 34, which may be of rubber or some other suitable material and which serves the same function as the plug 24 described above in connection with the Fig. 2 form of the invention. The tubular member 29 may be mechanically crimped about the plug 34 and to the safety fuse 30, each by one or more annular crimping zones shown as grooves 35 and 36 respectively, so as mechanically to hold the ignition cord and the safety fuse in the desired relative position as shown in the drawing. Suitable sealing means may be provided as shown at 31 and 38, each preferably comprising a wax-like sealing composition for protecting the joint between the tubular member 29 and the safety fuse and ignition cord respectively to prevent ingress of mosture into the ignition Zone shown as the chamber 3|.

While there is herein shown and described several forms of the present invention, including the preferred form shown in Fig. l, I do not wish to be limited to the forms herein particularly shown and specifically described, but rather intend that the invention shall include all reasonable equivalents thereof which will occur to those skilled in the art from the present disclosure.

I claim:

1. A Water-resistant connecting device for ignitively joining a safety fuse to a line of ignition cord usable in the sequential ring of explosives, comprising a tubular member of a size freely to receive an end of said safety fuse, a piece of deformable ignition cord arranged to be connectible to the line of ignition cord and having one end portion projected into said tubular member to a predetermined point therein, an oxygen-sufficient combustible composition disposed about an end portion of said ignition cord adjacent to said point, means for mechanically securing said piece of ignition cord in said tubular member, and means for mechanically securing an end of a piece of safety fuse, which may be projected into said tubular member, in ignitive proximity to said piece of ignition cord at said point for preventing accidental withdrawal of the safety fuse from said tubular member once it has been inserted thereinto.

2. A water-resistant connecting device for ignitively joining an ignition cord and a safety fuse usable for igniting a charge of blasting explosive, comprising a tubular member for receiving an end portion of said ignition cord and an end portion of said safety fuse in igniting proximity to one another, means associated :with said tubular member for gripping a portion of a piece of safety fuse projected thereinto to hold said safety fuse against accidental displacement therefrom, a length of ignition cord having one end portion projecting into the other end of said tubular member and having a part of this end portion within said tubular member gathered into a mass of greater diameter than that of said ignition cord, said mass being located at a predetermined point within said tubular member, an oxygensufficient combustible composition disposed on at least a part of said mass, a wire fastening means for mechanically securing said ignition cord in the end of said tubular member through which it projects, and means for sealing the end of said tubular member to said ignition cord when it is in its position as aforesaid to prevent ingress of moisture into said tubular member around said ignition cord.

3. As an article of manufacture, a Water-resistant connecting device for ignitively joining a safety fuse to a line of ignition cord, usable in the sequential firing of explosives, comprising a tubular member of a size freely to receive an end of a piece of Safety fuse, a piece of ignition cord having a central core of deformable metallic wire arranged for connection to the line of ignition cord and having one end portion projected into said tubular member to a predetermined point therein, means for mechanically securing said piece of ignition cord in said tubular member, and means for mechanically securing an end of a piece of safety fuse which may be projected into said tubular member in the use of the device in ignitive proximity at said point to the end portion of the piece of ignition cord secured therein, for preventing accidental withdrawal of said safety fuse from said tubular member once it has been inserted thereinto, whereby in the use of said connecting device, in ignitively joining a safety fuse to a line of ignition cord in the sequential firing of explosives, the connection between said piece of ignition cord including the 'wire core thereof will serve to prevent physical dislocation of the lighted piece of ignition cord aforesaid, so as to prevent the uncontrolled igniting of other combustible fuse means, including other points on said line of ignition cord, whereby to prevent the firing of a plurality of charges of explosive out of a desired sequence.

4. As an article of manufacture, a water-resistant connecting device in accordance with claim 2, wherein said length of ignition cord includes a core of deformable metallic wire extending continuously throughout said length of ignition cord, whereby in the use of the connecting device in ignitively joining a safety fuse to a line of ignition cord in the sequential ring of explosives, the connection between said length of ignition cord including the Iwire core thereof will serve to prevent the physical dislocation of the lighted length of ignition cord aforesaid, so as to prevent the uncontrolled igniting of other combustible fuse means, including other points on the line of ignition cord, whereby to prevent the firing of a plurality of charges of explosive out of a desired sequence.

JOHN D. RICH.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 645,849 Fuszner Mar. 20, 1900 713,878 Heath et al Nov. 18, 1902 953,588 Bramwell-Smith Mar. 29, 1910 1,645,379 Fletcher et al Oct. 11, 1927 2,253,549 Barton Aug. 26. 1941 FOREIGN PATENTS Number Country Date 34,195 France Nov. 30. 1928

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