CA2054115A1 - Explosive cable connector - Google Patents
Explosive cable connectorInfo
- Publication number
- CA2054115A1 CA2054115A1 CA 2054115 CA2054115A CA2054115A1 CA 2054115 A1 CA2054115 A1 CA 2054115A1 CA 2054115 CA2054115 CA 2054115 CA 2054115 A CA2054115 A CA 2054115A CA 2054115 A1 CA2054115 A1 CA 2054115A1
- Authority
- CA
- Canada
- Prior art keywords
- explosive
- cable connector
- sleeve
- cable
- spacer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Abstract
Abstract Explosive Cable Connector An explosive cable connector comprising a metal sleeve adapted to receive at least one wire or cable end, a winding of an explosive material to compress the sleeve on to the cable, and an inert space inserted between the windings of the explosive material so that the lateral propagation velocity of the explosive is reduced. The cable connector provides an improved means for joining cable ends.
Description
ICIC~N 798 Explosive Cable Connector Field of the Invention This invention relates to a method and apparatus ~or the joining of wire, cables, rods, high tension lines and the like, by explosive compression. In particular, the invention relates to a method for connecting the ends of wires and the like by explosively compressing a metal sleeve around the wire.
Description of the Related Art Explosive cable connectors, are known in the explosives technology industry, and are used to attach the ends o~ wire cables and the like, to each other, or to attach the end of a wire cabla to, for example, a terminal fastening device such as a guy-wire termination. These device~ hav2 been 15 described in various publications, including ~.S. Patents Nos. 3,684,820, 3,668,778 and 3,705,256.
In all of these patent~ a device is described having a hollow cylindric~l metal tube or sleeve, into which at lea~t one cable end is insertedO Around the sleeve is a helical winding of a explosive, typically a length o~ detonating cord, which has been wound around the sleeve. The detonating cord is wrapped around the metal sleeve so that adjacent windings of the detonating cord are in contact with one another.
These devices can be employed as terminations for a conductor or a structural cable, and the sleeve to be compressed may ~e open at both ends or may be a "blind'l cavity depending on its intended use. In either case t the device is designed to receive one conductor or cable end and 10 the explosive charge and initiating point are designed accordingly.
Alternatively, the connector may be employed as a device for joining two conductors or cables together. In this embodiment, a symmetrical sleeve and explosive charge 15 arrangement is desiyned with a central initiation point for propagation of the implosive compression on both cable ends symmetrically, and simultaneously.
In the embodiment wherein the device is used to connect two cable ends, and one end of cable has been înserted into 20 each end of the sleeve, the explosive winding is initiated by an explosive detonator, or the like, near the middle of the winding. The explosive, or "implosive", force ~rom the detonated explosive deforms the sleeve so that the sleeve is compressed around each cable end, and forms a bond with the 25 cable-The detonating cords used in this application,typically have a lengthwise detonation velocity (i.e. the velocity at which, in a straight length of cord, d~tonation would be propagated) of from 6.1 to 6.7 km/sec. When wound 30 on the metal sleeve, the lateral propagation velocity o~ the cord (i.e. the velocity at which the explosion propagates along the length of the sleeve) is typically in the range o~
3.9 to 5.1 km/sec~ This lateral propagation rate i~
determined by the rate at which the exploding detonating I IC~N 798 cord initiates the adjacent winding of detonating cord through the layers of inert covering material~
A wide variety of metals, such as aluminum, steel or suitable metal alloys, are used to fabricate the hollow metal sleeve. The metal sl~eve i5 typically protected with a tightly fitted, protective sleeve made o~ ~lexible polyvinyl chloride (PVC). This PVC ~leeve is typically 2 or 3 mm in thickness, and is posi~ioned between the metal sleevP and the detonating cord. The protective sleev~
protects the metal sleeve ~rom scarring by ~he detonation.
Depending on the size and construction of the metal sleeve, the strength of the explosiv~ impulse is adjusted in order to compre~s the sleeve properly on the cahle. The explosive force may be adjusted by the number o~ windings o~
15 detonating cord, i~e. by adding additional layer~ of detonating ~ord over the first layer, or by adjusting the explosive energy of the detonating cord used.
Methods of adju~king the explosive energy of the detonating cord, include adjusting the amount o~ explosive 20 present in the core of the detonating cord (i.e. the explosive load expressed as g/m), or by adjusting the materials of construction of the non-explosive outer layerfi of the cord (iOe. adjusting the cord diameter). While it is possible to provide a wide range of de~onating cord construction which will provide adequate compressive properties for most cable connector applications, it would be necessary to have available a wide variety o~ detonating cord~ to service all application~. Maintaining this inventory of detonating cord adds to the expense of 30 providing a wide range of cable connectors.
It has also been observed that, in work with high-performance steel sleeves and cable, problems have been encountered with prior art cable connectors, with poor gripping of the connector to the cable. This problem i~
35 believed to be related to an elastic recovery by the sleeve f~
after the compressive impulse has occurred, and may be solved by slowing the lateral propagativn velocity of the detonating cord so that elastic recovery i6 minimized.
While this problem can be overcome by designing a new detonating cord construction, this additional cord would add to the i~ventory of detonation cords necessary.
Thus, it would be desirable to provide a cable connector wherein the latexal propagation velocity of a standard detonating cord can be modified and controlled.
Summarv of the Invention Accordingly, it is an object of the present invention to provide a method to modify and control the lateral propagation velocity of the detonating cord of an explosiv~
cable connector.
It is a further object of the pr~sent invention to pxovide an explosive cable connector wherein the lateral propagation velocity of the the detonating cord is modified and controlled.
It is yet a further object of the present invention to 20 provide a method for connecting an explosive cable connector to a cable or the like, by initiating an explosive cable connector, wherein the lateral propagation velocity of the detonating cord of the explosive cable connector has been modified and controlled~
These and other objects are accomplished ~y providing an explosive cable connector wherein a winding of a spacer cord o~ a substantially inert material has been inserted between the windings of detonating cQrd on the sleeve of the connector. The windings of the inert spacer thus separate the detona~ing cord windings. By adju tment of the size and construction of the inert spacer, the lateral propagation velocity of a standard detonating cord may thus be modified and controlled.
ICIC~N 798 Accordingly, the present invention provides an explosive cable connector comprising:
i) a hollow metal sleeve having a ~irst end adapte~ to receive a first cable end within said sleeve;
ii) a winding of an explosive material in contact with, and around the outer surface of said ~irst end o~ said sleeve, so that upon detonation of said explosive material, said hollow metal sleeve is compressed 60 as to become attached to said first cable end; and iii) a spacer of a suhstantially inert material located ~: between the windings of said explosive material, so that the lateral propagation velocity of the explosive material i6 reduced.
Preferably, the lateral propagation velocity i~ reduced to a value less than 5.0 km~sec, more preferably less than 4.3 km/sec, and yet still more preferably to a value les~
than 4.0 km/sec.
The term explos;ve cable connector refers to any implosive compression connector. The term cable is used throughout this specification, and refers to any suitable wire, cable, rod or the like, which can be used in an implosive compression COnnectQrO
The winding of the explosive material is preferably a single strand of detonating cord which has been wrapped 25 around the sleeve~ Preferably, the spacer o~ a substantially inert material ~hereinafter referred to as ths inert spacer) is also a single strand of material which i~
also wrapped around the sleeveO The adjacent windings of the explosive material are thus separated by the inert 30 spacer.
In a preferred configuration, the explosiv2 winding and the inert spacer form a double helix configuration (also termed as a "double start" arrangement) on the sleeve of the cable connector.
The inert spacer is generally constructed o~ any -6- ~3 ~ Ic~AN 7~8 material which does nok ~erve to increase or maintaln the lateral propagation velocity at the lateral propagation velocity level of a winding of explosive material only.
Preferably, the substantially inert material u~ed to manufacture the inert spacer is a material which i~
combustible, and thus is partially or completely destroyed by the datonation of the e~plosive ma~erial in the cable connector.
The inert spacer is preferably a shock-damping material 10 in that it absorbs some of the lateral explosive energy and thus retards the lateral propagation of the e~plosive. ~he inert spacer must however, not be too compressible in order to ensure an even distribution of the implosive force~
~ The inert spacer may be made of any suitable material.
15 However, a preferred construction compris~s a flexible PVC
rod or a braided sa~h cord.
The metal sleeve is made of any suitable metal which is deformable under the compressive force of the explosive material. For example, these metals may include aluminu~, 20 steel or suitable metal alloys. ~he sleeve may have one or more ends adapted to receive cables, with each end preferably having a double helix winding of detonating cord and an inert spacer. In one embodiment of a cable connector, the sleeve is a hollow metal tube into which a 25 cable end is inserted into each end of the tube. A
continuous winding of detonating cord and an inert spacer can then extend from virtually one end of the sle~ve to the second end of the ~leeve.
Accordingly, the present invention also provides an 30 explosive cable connector as described hereinabove wherein said sleeve additionally comprises a second end adapted to receive a second cable end, and said winding of said explosive material, and said spacer of substantially inert material, are in contack with, and around, the outer surface 35 of said firsk and said second end of said sleeve.
Description of the Related Art Explosive cable connectors, are known in the explosives technology industry, and are used to attach the ends o~ wire cables and the like, to each other, or to attach the end of a wire cabla to, for example, a terminal fastening device such as a guy-wire termination. These device~ hav2 been 15 described in various publications, including ~.S. Patents Nos. 3,684,820, 3,668,778 and 3,705,256.
In all of these patent~ a device is described having a hollow cylindric~l metal tube or sleeve, into which at lea~t one cable end is insertedO Around the sleeve is a helical winding of a explosive, typically a length o~ detonating cord, which has been wound around the sleeve. The detonating cord is wrapped around the metal sleeve so that adjacent windings of the detonating cord are in contact with one another.
These devices can be employed as terminations for a conductor or a structural cable, and the sleeve to be compressed may ~e open at both ends or may be a "blind'l cavity depending on its intended use. In either case t the device is designed to receive one conductor or cable end and 10 the explosive charge and initiating point are designed accordingly.
Alternatively, the connector may be employed as a device for joining two conductors or cables together. In this embodiment, a symmetrical sleeve and explosive charge 15 arrangement is desiyned with a central initiation point for propagation of the implosive compression on both cable ends symmetrically, and simultaneously.
In the embodiment wherein the device is used to connect two cable ends, and one end of cable has been înserted into 20 each end of the sleeve, the explosive winding is initiated by an explosive detonator, or the like, near the middle of the winding. The explosive, or "implosive", force ~rom the detonated explosive deforms the sleeve so that the sleeve is compressed around each cable end, and forms a bond with the 25 cable-The detonating cords used in this application,typically have a lengthwise detonation velocity (i.e. the velocity at which, in a straight length of cord, d~tonation would be propagated) of from 6.1 to 6.7 km/sec. When wound 30 on the metal sleeve, the lateral propagation velocity o~ the cord (i.e. the velocity at which the explosion propagates along the length of the sleeve) is typically in the range o~
3.9 to 5.1 km/sec~ This lateral propagation rate i~
determined by the rate at which the exploding detonating I IC~N 798 cord initiates the adjacent winding of detonating cord through the layers of inert covering material~
A wide variety of metals, such as aluminum, steel or suitable metal alloys, are used to fabricate the hollow metal sleeve. The metal sl~eve i5 typically protected with a tightly fitted, protective sleeve made o~ ~lexible polyvinyl chloride (PVC). This PVC ~leeve is typically 2 or 3 mm in thickness, and is posi~ioned between the metal sleevP and the detonating cord. The protective sleev~
protects the metal sleeve ~rom scarring by ~he detonation.
Depending on the size and construction of the metal sleeve, the strength of the explosiv~ impulse is adjusted in order to compre~s the sleeve properly on the cahle. The explosive force may be adjusted by the number o~ windings o~
15 detonating cord, i~e. by adding additional layer~ of detonating ~ord over the first layer, or by adjusting the explosive energy of the detonating cord used.
Methods of adju~king the explosive energy of the detonating cord, include adjusting the amount o~ explosive 20 present in the core of the detonating cord (i.e. the explosive load expressed as g/m), or by adjusting the materials of construction of the non-explosive outer layerfi of the cord (iOe. adjusting the cord diameter). While it is possible to provide a wide range of de~onating cord construction which will provide adequate compressive properties for most cable connector applications, it would be necessary to have available a wide variety o~ detonating cord~ to service all application~. Maintaining this inventory of detonating cord adds to the expense of 30 providing a wide range of cable connectors.
It has also been observed that, in work with high-performance steel sleeves and cable, problems have been encountered with prior art cable connectors, with poor gripping of the connector to the cable. This problem i~
35 believed to be related to an elastic recovery by the sleeve f~
after the compressive impulse has occurred, and may be solved by slowing the lateral propagativn velocity of the detonating cord so that elastic recovery i6 minimized.
While this problem can be overcome by designing a new detonating cord construction, this additional cord would add to the i~ventory of detonation cords necessary.
Thus, it would be desirable to provide a cable connector wherein the latexal propagation velocity of a standard detonating cord can be modified and controlled.
Summarv of the Invention Accordingly, it is an object of the present invention to provide a method to modify and control the lateral propagation velocity of the detonating cord of an explosiv~
cable connector.
It is a further object of the pr~sent invention to pxovide an explosive cable connector wherein the lateral propagation velocity of the the detonating cord is modified and controlled.
It is yet a further object of the present invention to 20 provide a method for connecting an explosive cable connector to a cable or the like, by initiating an explosive cable connector, wherein the lateral propagation velocity of the detonating cord of the explosive cable connector has been modified and controlled~
These and other objects are accomplished ~y providing an explosive cable connector wherein a winding of a spacer cord o~ a substantially inert material has been inserted between the windings of detonating cQrd on the sleeve of the connector. The windings of the inert spacer thus separate the detona~ing cord windings. By adju tment of the size and construction of the inert spacer, the lateral propagation velocity of a standard detonating cord may thus be modified and controlled.
ICIC~N 798 Accordingly, the present invention provides an explosive cable connector comprising:
i) a hollow metal sleeve having a ~irst end adapte~ to receive a first cable end within said sleeve;
ii) a winding of an explosive material in contact with, and around the outer surface of said ~irst end o~ said sleeve, so that upon detonation of said explosive material, said hollow metal sleeve is compressed 60 as to become attached to said first cable end; and iii) a spacer of a suhstantially inert material located ~: between the windings of said explosive material, so that the lateral propagation velocity of the explosive material i6 reduced.
Preferably, the lateral propagation velocity i~ reduced to a value less than 5.0 km~sec, more preferably less than 4.3 km/sec, and yet still more preferably to a value les~
than 4.0 km/sec.
The term explos;ve cable connector refers to any implosive compression connector. The term cable is used throughout this specification, and refers to any suitable wire, cable, rod or the like, which can be used in an implosive compression COnnectQrO
The winding of the explosive material is preferably a single strand of detonating cord which has been wrapped 25 around the sleeve~ Preferably, the spacer o~ a substantially inert material ~hereinafter referred to as ths inert spacer) is also a single strand of material which i~
also wrapped around the sleeveO The adjacent windings of the explosive material are thus separated by the inert 30 spacer.
In a preferred configuration, the explosiv2 winding and the inert spacer form a double helix configuration (also termed as a "double start" arrangement) on the sleeve of the cable connector.
The inert spacer is generally constructed o~ any -6- ~3 ~ Ic~AN 7~8 material which does nok ~erve to increase or maintaln the lateral propagation velocity at the lateral propagation velocity level of a winding of explosive material only.
Preferably, the substantially inert material u~ed to manufacture the inert spacer is a material which i~
combustible, and thus is partially or completely destroyed by the datonation of the e~plosive ma~erial in the cable connector.
The inert spacer is preferably a shock-damping material 10 in that it absorbs some of the lateral explosive energy and thus retards the lateral propagation of the e~plosive. ~he inert spacer must however, not be too compressible in order to ensure an even distribution of the implosive force~
~ The inert spacer may be made of any suitable material.
15 However, a preferred construction compris~s a flexible PVC
rod or a braided sa~h cord.
The metal sleeve is made of any suitable metal which is deformable under the compressive force of the explosive material. For example, these metals may include aluminu~, 20 steel or suitable metal alloys. ~he sleeve may have one or more ends adapted to receive cables, with each end preferably having a double helix winding of detonating cord and an inert spacer. In one embodiment of a cable connector, the sleeve is a hollow metal tube into which a 25 cable end is inserted into each end of the tube. A
continuous winding of detonating cord and an inert spacer can then extend from virtually one end of the sle~ve to the second end of the ~leeve.
Accordingly, the present invention also provides an 30 explosive cable connector as described hereinabove wherein said sleeve additionally comprises a second end adapted to receive a second cable end, and said winding of said explosive material, and said spacer of substantially inert material, are in contack with, and around, the outer surface 35 of said firsk and said second end of said sleeve.
2 ~
Particular advantages can be achieved with speci~ic ratios of the diameters of the cords of explosive material and the inert spacer. Rigorous geometry can be calculated in theory, on the assumption that neither cord is radially deformable. Accordingly, it can be calculated that a preferred range o~ diameters for the inert spacer is between 28 and 61% o~ the diameter of tha explosive material, and more preferably between about ~0 and 55% of the e~plosi~e material diameter. It is believed that for an inert spacer 10 diameter ~elow about 27~ of the diameter of the explosiYe material, the spacing effect (i.e. the spacing apart of the windings of the explosive material~ ls too small to achieve the desired decrease in lateral propagation velocity.
It is also believed that an inert spacer diameter of 15 greater than 62% of the diameter of the explosive material i5 not desired since the inert spacer may interfere with the packing of a second and any subsequent layers of explosive material required to provide the necessary energy.
The inert spac~r diameter may be 62% or greater than 20 the diameter of the explosive material, however; with a larger inert spacer, greater care must be taken during the positioning of the second and any ubsequent layers so that the second and subseguent layers are not substantially in contact with adjacent windings in the same layer~ Further, 25 the inert spacer æhould not ~ so large as to prevent latera~ propagation of the explosive materialO
While additional layers o~ explosive may be required, for increased energy, pre~erably, only the first layer of explosive material (i.e. the layer in contact with ~he sleeve) requires the winding of the inert spacer since the inert spacer can be used to establish the spacing for additional layers of the explosi~e material.
While the first, econd and any subseguent layers may be in contact with one another, the winding of the explosive 35 material must not be in contact with the adjacent winding of explosive material from the same layer, since this would provide an alternate route for maintaining the lateral propagation ~elocity.
When a multiple-layer winding is constructed with the preferred inert spacer diameter, the second layer o~
explosive material is self-locating in the groove created in the first layer by the inert spacer, Furtharmore, a groove of the same shape is formed in each subsequent layer; thus no extra inert spacer is required after the first layer.
In an additional aspect, the present invention also provides a method of reducing the lateral propagation rate of an explosive cable connector comprising:
i) providing a hollow metal sleeve having a first end adapted to receive a first cable end within said sleeve:
ii) providiny a winding of an explosive material in contact with, and around the outer surface of said first end of said sleeve, and iii) inserting a spa~er of a substantially inert material between the winding of said explosive material~
In a further aspect, the present invention also provides a method of attaching a cable, or the like, to a cable connector comprising:
a) inserting an end of a cable into a cable connector, which cable connector comprises:
i) a hollow metal sleeve having a ~irst end adapted to receive said cable and within said sleeve;
ii) a winding of an explosive material in contact with, and around the outer surface of said first end o~ said sleeve; and iii) a spacer of a substantially inert material between the winding of said explosive material; and b) initiating said explosive material so that upon detonation of said explosive material, said hollow metal sleeve is compressed so as to become attached to said first 35 cable end.
f~
_ 9 ,l Brief Description of the Drawin~
The present invention will now be described by way o~
example only, with refarence to the attached drawings, in which:
Figure 1 is a perspective drawing o~ a prior art cable connector;
Figure 2 is a cross-sectional drawing o~ a cable connector according to the present invention; and : Figure 3a through 3c are cxoss-sectional views of the cord packing around the sleeve o~ the cable connector.
In Figure 1 a prior art cable connector 10 is depicted, having a metal sleeve 12 around which a protective PVC
sleeve 13 has been placed. Ovex the PVC sleeve 13, a ~irst layer of a continuous length of detonating cord 14 has been 15 wound. A second layer of a continuous length of detonating cord 16 has been wound over a psrtion of first layer 14.
Detonating cord 16 may be o~ the same strength and composition as cord 14. However, cord 16 may have more or less explosive load than cord 14.
Metal sleeve 12 is a hollow tube, and has a ~irst opening 18 adapted to rèceive a first wire or cable. A
second opening (not shown) at the opposite end of sleeve is adapted to receive the end of a second wire or cable.
In operation, detonating cords 14 and 16 are initiated 25 by a suitable detonator which has been temporarily affixed near the middle of cable connector 10. A~ the detonating cord e~plodes, its explosive force compresses sleeve 12, and causes the initiation of the adjacent winding of detonating cord 14 and/or 16. The detonation of the detonating cords 30 14 and 16 thus proceeds from the middle of th2 device towards the ends of sleeve 12l The compressive force from detonating cords 14 and 16 causes sleeve 12 to clamp on to, or mold around, the ~irst ICIC~N 7g8 --10~
and sec~nd wires or cables which have been inserted into sleeve 12, and thus holds the ends of the first and second wires or cables toge~her in ~he sleeve.
In Fiqure 2, a longitudinal cross-sectional vlew of a cable connector according to ~he presen~ inven~ion is shown.
Cable connector 20 also comprises a metal sleeve 22 having a openi~g 24,26 at each end which openings are adapted to receive the ends of a first and a second wire or cable.
Around sleeve 22 is a protective PVC sleeve 23 and a fir6t layer of detonating cord 28. The windings of cord 28 ar~
separated by a cont;nuous winding of an inert spacer 30 made of a flexible PVC rod or a braided sash cord. The diameter of inert spacer 30 is approximately 60% of the diameter of detonating cord 28.
In operation, detonating cord 28 is initiated by a suitable detonator which detonator has been affixed near the middle of cable connector 20. The detonation of detonating cord 28 again compresses sleeve 22 tQ clamp on to the wireR
which have been inserted into the sleeve. HoweYer, the 20 propagation of the explosive along the length of sleeve 22 is delayed because inert spacer 30 absorbs part of the lateral explosive force from detonating cord 28.
In Figures 3, a) to c), an enlarged view of a series o~
arrangements for the windings of a first detonating cord 40, and optionally a second or third layer of detonating cord, 42 and 44 respectively, and an inert spacer 46, around the protective PVC sleeve 43 covering a metal sleeve 48, are shownO
In Figure 3a, a configuration is shown having only one layer of ~etonating cord 40 and inert spacer 46. In this configuration, inert spacer 46 is the same diameter as detonating cord 40.
In Figure 3b, a configuration is shown having 2 layer6 of detonating cord, 40 and 42, and having a inerk spacer 46 35 inserted between the windings of detona~ing cord 40. Inert ~
ICIC~N 79B
spacer 46 has a diame~er of about 60% of the diameter of detonating cords ~0 and ~. Detonating cord 42 i~
positioned in the grooves formed by inert spacer 46, thu providing a gap between ~he adjacent windings o~ detonating cord 42. In operation, propagation o~ the explosive i~ this embodiment would be delayed since the shock wave would travel back and forth between the Pirst and second layer of detonating cord.
In Figure 3c, a configuration is shown having 3 layers of detonating cord, 40, 42, and 44, and having an inert ! spacer 46 inserted between the windings o~ detonating cord 40. Inert spacer 46 has a diameter o~ about ~0% o~ the diameter of detonating cord 40. Detonating ~ord 42 ls positioned in the grooves formed in the first layer of detonating cord 40 and iner~ spacer 46, and detonating cord 44 is position in the gap formed in the second layer of detonating cord 42.
Examples The advantages of the present invention will now be 20 described, by way of exampl~ only, by reference to the following examples.
ExamPle 1 A two-layer-winding cable connector (i.e. having a first layer and a second layer of detonating cord) was 25 constructed on a steel tube, which steel t~be had 2 mm thick, protective PVC sleeve. The detonating cord was the same for both layers and had a nominal diameter of 6.0 ~m.
For comparison purposes, the cable connector was constructed without an inert spacer, and thus was not in accordance with 30 the present invention.
When initiated, the cable connector had a latexal propagation velocity of 4.69 km/sec.
A second cable connector was prepared using the same materials as above, with a flexible PVC spacer cord o~
nominal diameter of 4.0 mm. inserted between the windinys of the first layer o~ the detonating cord. This cable connector was, thus in accordance with the present invention. When initiated, the cable connector had a lateral propagation velocity of 3.83 kmJsec.
Accordingly~ it can be noted that the inert spacer significantly reduced the lateral propagation velscity o~
: the cable connector. ~wo factors likely contribute to thi~
reduction in velocity, namely the larger ~ap between turns on a given layer, and a longer propagation path of the contacting cord in adjacent layers.
15 Example 2 Cable connectors having multi-layer windings were constructed on steel sleeves, which sleeves had inside and outside diameters of nominal dimensions 13.5 and 2B mm respectively. The cable connectors compress~d implosively 20 around 12.5 mm seven-strand galvanized wire of Grade 220 steel. In the cable connector constructed without the inert spacer, the compressed joints were found to have strongly constricted sections corresponding to the ends of the windings, and a characteristically smaller compression over 25 an extensive middle portion. In tension tests, these joints had a pronounced tendency to pull out slowly over prolonged loading at or above about 65% of the rated breaking strength (RBS). When stressed at a sufficient rate to produc~
breaking failure, the break typically occurred inside the 30 mouth of the sleeve.
In contrast, when the cable connector was prepared with the same detonating cord, and a braided sash cord spacer having a nominal diameter of 3.2 mm, the joints were found ?, ~
~13-to have neg~.igible slip at a tension load o~ 75%, and at 100~ RBS, a small amount of slippage occurred, which stopped after a brief period. When the joint was tested to the breaking limit, breakage of the wire occurred in mid span, remote from the sleeves. When the compressed sleeves were examined, they were found to have a uniform diameter over the full length of the winding section.
Further, the inert spacer reduced the am~unt o~
explosive used in at least the ~irst layer, and in the second and subseguent layers when the detonating cord is positioned only in the groove formed by the i~sert material spacer. Thus, in Example 2, the cable connector prepared according to the present invention, contained about 40% le~s explosive than the prior art cable connector, and yet 15 demonstrated improved properties.
Having described specific embodiments of the present invention, it will be understood that modifications thereof may be sugg sted to those skilled in the art, and it is intended to cover all such modifications as fall within the 20 scope of the appended claims.
Particular advantages can be achieved with speci~ic ratios of the diameters of the cords of explosive material and the inert spacer. Rigorous geometry can be calculated in theory, on the assumption that neither cord is radially deformable. Accordingly, it can be calculated that a preferred range o~ diameters for the inert spacer is between 28 and 61% o~ the diameter of tha explosive material, and more preferably between about ~0 and 55% of the e~plosi~e material diameter. It is believed that for an inert spacer 10 diameter ~elow about 27~ of the diameter of the explosiYe material, the spacing effect (i.e. the spacing apart of the windings of the explosive material~ ls too small to achieve the desired decrease in lateral propagation velocity.
It is also believed that an inert spacer diameter of 15 greater than 62% of the diameter of the explosive material i5 not desired since the inert spacer may interfere with the packing of a second and any subsequent layers of explosive material required to provide the necessary energy.
The inert spac~r diameter may be 62% or greater than 20 the diameter of the explosive material, however; with a larger inert spacer, greater care must be taken during the positioning of the second and any ubsequent layers so that the second and subseguent layers are not substantially in contact with adjacent windings in the same layer~ Further, 25 the inert spacer æhould not ~ so large as to prevent latera~ propagation of the explosive materialO
While additional layers o~ explosive may be required, for increased energy, pre~erably, only the first layer of explosive material (i.e. the layer in contact with ~he sleeve) requires the winding of the inert spacer since the inert spacer can be used to establish the spacing for additional layers of the explosi~e material.
While the first, econd and any subseguent layers may be in contact with one another, the winding of the explosive 35 material must not be in contact with the adjacent winding of explosive material from the same layer, since this would provide an alternate route for maintaining the lateral propagation ~elocity.
When a multiple-layer winding is constructed with the preferred inert spacer diameter, the second layer o~
explosive material is self-locating in the groove created in the first layer by the inert spacer, Furtharmore, a groove of the same shape is formed in each subsequent layer; thus no extra inert spacer is required after the first layer.
In an additional aspect, the present invention also provides a method of reducing the lateral propagation rate of an explosive cable connector comprising:
i) providing a hollow metal sleeve having a first end adapted to receive a first cable end within said sleeve:
ii) providiny a winding of an explosive material in contact with, and around the outer surface of said first end of said sleeve, and iii) inserting a spa~er of a substantially inert material between the winding of said explosive material~
In a further aspect, the present invention also provides a method of attaching a cable, or the like, to a cable connector comprising:
a) inserting an end of a cable into a cable connector, which cable connector comprises:
i) a hollow metal sleeve having a ~irst end adapted to receive said cable and within said sleeve;
ii) a winding of an explosive material in contact with, and around the outer surface of said first end o~ said sleeve; and iii) a spacer of a substantially inert material between the winding of said explosive material; and b) initiating said explosive material so that upon detonation of said explosive material, said hollow metal sleeve is compressed so as to become attached to said first 35 cable end.
f~
_ 9 ,l Brief Description of the Drawin~
The present invention will now be described by way o~
example only, with refarence to the attached drawings, in which:
Figure 1 is a perspective drawing o~ a prior art cable connector;
Figure 2 is a cross-sectional drawing o~ a cable connector according to the present invention; and : Figure 3a through 3c are cxoss-sectional views of the cord packing around the sleeve o~ the cable connector.
In Figure 1 a prior art cable connector 10 is depicted, having a metal sleeve 12 around which a protective PVC
sleeve 13 has been placed. Ovex the PVC sleeve 13, a ~irst layer of a continuous length of detonating cord 14 has been 15 wound. A second layer of a continuous length of detonating cord 16 has been wound over a psrtion of first layer 14.
Detonating cord 16 may be o~ the same strength and composition as cord 14. However, cord 16 may have more or less explosive load than cord 14.
Metal sleeve 12 is a hollow tube, and has a ~irst opening 18 adapted to rèceive a first wire or cable. A
second opening (not shown) at the opposite end of sleeve is adapted to receive the end of a second wire or cable.
In operation, detonating cords 14 and 16 are initiated 25 by a suitable detonator which has been temporarily affixed near the middle of cable connector 10. A~ the detonating cord e~plodes, its explosive force compresses sleeve 12, and causes the initiation of the adjacent winding of detonating cord 14 and/or 16. The detonation of the detonating cords 30 14 and 16 thus proceeds from the middle of th2 device towards the ends of sleeve 12l The compressive force from detonating cords 14 and 16 causes sleeve 12 to clamp on to, or mold around, the ~irst ICIC~N 7g8 --10~
and sec~nd wires or cables which have been inserted into sleeve 12, and thus holds the ends of the first and second wires or cables toge~her in ~he sleeve.
In Fiqure 2, a longitudinal cross-sectional vlew of a cable connector according to ~he presen~ inven~ion is shown.
Cable connector 20 also comprises a metal sleeve 22 having a openi~g 24,26 at each end which openings are adapted to receive the ends of a first and a second wire or cable.
Around sleeve 22 is a protective PVC sleeve 23 and a fir6t layer of detonating cord 28. The windings of cord 28 ar~
separated by a cont;nuous winding of an inert spacer 30 made of a flexible PVC rod or a braided sash cord. The diameter of inert spacer 30 is approximately 60% of the diameter of detonating cord 28.
In operation, detonating cord 28 is initiated by a suitable detonator which detonator has been affixed near the middle of cable connector 20. The detonation of detonating cord 28 again compresses sleeve 22 tQ clamp on to the wireR
which have been inserted into the sleeve. HoweYer, the 20 propagation of the explosive along the length of sleeve 22 is delayed because inert spacer 30 absorbs part of the lateral explosive force from detonating cord 28.
In Figures 3, a) to c), an enlarged view of a series o~
arrangements for the windings of a first detonating cord 40, and optionally a second or third layer of detonating cord, 42 and 44 respectively, and an inert spacer 46, around the protective PVC sleeve 43 covering a metal sleeve 48, are shownO
In Figure 3a, a configuration is shown having only one layer of ~etonating cord 40 and inert spacer 46. In this configuration, inert spacer 46 is the same diameter as detonating cord 40.
In Figure 3b, a configuration is shown having 2 layer6 of detonating cord, 40 and 42, and having a inerk spacer 46 35 inserted between the windings of detona~ing cord 40. Inert ~
ICIC~N 79B
spacer 46 has a diame~er of about 60% of the diameter of detonating cords ~0 and ~. Detonating cord 42 i~
positioned in the grooves formed by inert spacer 46, thu providing a gap between ~he adjacent windings o~ detonating cord 42. In operation, propagation o~ the explosive i~ this embodiment would be delayed since the shock wave would travel back and forth between the Pirst and second layer of detonating cord.
In Figure 3c, a configuration is shown having 3 layers of detonating cord, 40, 42, and 44, and having an inert ! spacer 46 inserted between the windings o~ detonating cord 40. Inert spacer 46 has a diameter o~ about ~0% o~ the diameter of detonating cord 40. Detonating ~ord 42 ls positioned in the grooves formed in the first layer of detonating cord 40 and iner~ spacer 46, and detonating cord 44 is position in the gap formed in the second layer of detonating cord 42.
Examples The advantages of the present invention will now be 20 described, by way of exampl~ only, by reference to the following examples.
ExamPle 1 A two-layer-winding cable connector (i.e. having a first layer and a second layer of detonating cord) was 25 constructed on a steel tube, which steel t~be had 2 mm thick, protective PVC sleeve. The detonating cord was the same for both layers and had a nominal diameter of 6.0 ~m.
For comparison purposes, the cable connector was constructed without an inert spacer, and thus was not in accordance with 30 the present invention.
When initiated, the cable connector had a latexal propagation velocity of 4.69 km/sec.
A second cable connector was prepared using the same materials as above, with a flexible PVC spacer cord o~
nominal diameter of 4.0 mm. inserted between the windinys of the first layer o~ the detonating cord. This cable connector was, thus in accordance with the present invention. When initiated, the cable connector had a lateral propagation velocity of 3.83 kmJsec.
Accordingly~ it can be noted that the inert spacer significantly reduced the lateral propagation velscity o~
: the cable connector. ~wo factors likely contribute to thi~
reduction in velocity, namely the larger ~ap between turns on a given layer, and a longer propagation path of the contacting cord in adjacent layers.
15 Example 2 Cable connectors having multi-layer windings were constructed on steel sleeves, which sleeves had inside and outside diameters of nominal dimensions 13.5 and 2B mm respectively. The cable connectors compress~d implosively 20 around 12.5 mm seven-strand galvanized wire of Grade 220 steel. In the cable connector constructed without the inert spacer, the compressed joints were found to have strongly constricted sections corresponding to the ends of the windings, and a characteristically smaller compression over 25 an extensive middle portion. In tension tests, these joints had a pronounced tendency to pull out slowly over prolonged loading at or above about 65% of the rated breaking strength (RBS). When stressed at a sufficient rate to produc~
breaking failure, the break typically occurred inside the 30 mouth of the sleeve.
In contrast, when the cable connector was prepared with the same detonating cord, and a braided sash cord spacer having a nominal diameter of 3.2 mm, the joints were found ?, ~
~13-to have neg~.igible slip at a tension load o~ 75%, and at 100~ RBS, a small amount of slippage occurred, which stopped after a brief period. When the joint was tested to the breaking limit, breakage of the wire occurred in mid span, remote from the sleeves. When the compressed sleeves were examined, they were found to have a uniform diameter over the full length of the winding section.
Further, the inert spacer reduced the am~unt o~
explosive used in at least the ~irst layer, and in the second and subseguent layers when the detonating cord is positioned only in the groove formed by the i~sert material spacer. Thus, in Example 2, the cable connector prepared according to the present invention, contained about 40% le~s explosive than the prior art cable connector, and yet 15 demonstrated improved properties.
Having described specific embodiments of the present invention, it will be understood that modifications thereof may be sugg sted to those skilled in the art, and it is intended to cover all such modifications as fall within the 20 scope of the appended claims.
Claims (16)
1. An explosive cable connector comprising:
i) a hollow metal sleeve having a first end adapted to receive a first cable end within said sleeve;
ii) a winding of an explosive material in contact with, and around the outer surface of said first end of said sleeve, so that upon detonation of said explosive material, said hollow metal sleeve is compressed so as to become attached to said first cable end; and iii) a spacer of a substantially inert material located between the windings of said explosive material, so that the lateral propagation velocity of the explosive material is reduced.
i) a hollow metal sleeve having a first end adapted to receive a first cable end within said sleeve;
ii) a winding of an explosive material in contact with, and around the outer surface of said first end of said sleeve, so that upon detonation of said explosive material, said hollow metal sleeve is compressed so as to become attached to said first cable end; and iii) a spacer of a substantially inert material located between the windings of said explosive material, so that the lateral propagation velocity of the explosive material is reduced.
2. An explosive cable connector as claimed in Claim 1 wherein said sleeve additionally comprises a second end adapted to receive a second cable end, and said winding of said explosure material, and said spacer of substantially inert material, are in contact with, and around, the outer surface of said first and said second end of said sleeve.
3. An explosive cable connector as claimed in Claim 1 wherein said winding of explosive material and said spacer of inert material form a double helix.
4. An explosive cable connector as claimed in Claim 3 wherein said explosive material is detonating cord.
5. An explosive cable connector as claimed in Claim 1 wherein said spacer of inert material is manufactured from a shock-damping material.
6. An explosive cable connector as claimed in Claim 1 wherein said spacer of inert material comprises a flexible polyvinyl chloride rod or a braided sash cord.
7. An explosive cable connector as claimed in Claim 1 wherein said hollow metal sleeve is fabricated from aluminum, steel or a metal alloy.
8. An explosive cable connector as claimed in Claim 1 wherein said hollow metal sleeve is a high performance steel.
9. An explosive cable connector as claimed in Claim 1 wherein the diameter of the spacer of inert material is between 28 and 61% of the diameter of the explosive material.
10. An explosive cable connector as claimed in Claim 9 wherein the diameter of the spacer of inert material is between 40 to 55% of the diameter of the explosive material.
11. An explosive cable connector as claimed in Claim 1 additionally comprising at least one additional layer of explosive material over the first layer of explosive material and the spacer of inert material.
12. An explosive cable connector as claimed in Claim 1 wherein the lateral propagation velocity is reduced to a value of less than 5.0 km/sec.
13. An explosive cable connector as claimed in Claim 12 wherein the lateral propagation velocity is reduced to a value of less than 4.3 km/sec.
14. An explosive cable connector as claimed in Claim 13 wherein the lateral propagation velocity is reduced to a value of less than 4.0 km/sec.
15. A method of reducing the lateral propagation rate of an explosive cable connector comprising:
i) providing a hollow metal sleeve having a first end adapted to receive a first cable end within said sleeve;
ii) providing a winding of an explosive material in contact with, and around the outer surface of said first end of said sleeve, and iii) inserting a spacer of a substantially inert material between the winding of said explosive material.
i) providing a hollow metal sleeve having a first end adapted to receive a first cable end within said sleeve;
ii) providing a winding of an explosive material in contact with, and around the outer surface of said first end of said sleeve, and iii) inserting a spacer of a substantially inert material between the winding of said explosive material.
16. A method of attaching a cable to a cable connector comprising:
a) inserting an end of a cable into a cable connector, which cable connector comprises:
i) a hollow metal sleeve having a first end adapted to receive said cable end within said sleeve;
ii) a winding of an explosive material in contact with, and around the outer surface of said first end of said sleeve; and iii) a spacer of a substantially inert material between the winding of said explosive material; and b) initiating said explosive material so that upon detonation of said explosive material, said hollow metal sleeve is compressed so as to become attached to said cable end.
a) inserting an end of a cable into a cable connector, which cable connector comprises:
i) a hollow metal sleeve having a first end adapted to receive said cable end within said sleeve;
ii) a winding of an explosive material in contact with, and around the outer surface of said first end of said sleeve; and iii) a spacer of a substantially inert material between the winding of said explosive material; and b) initiating said explosive material so that upon detonation of said explosive material, said hollow metal sleeve is compressed so as to become attached to said cable end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2054115 CA2054115A1 (en) | 1991-10-25 | 1991-10-25 | Explosive cable connector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2054115 CA2054115A1 (en) | 1991-10-25 | 1991-10-25 | Explosive cable connector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2054115A1 true CA2054115A1 (en) | 1993-04-26 |
Family
ID=4148628
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2054115 Abandoned CA2054115A1 (en) | 1991-10-25 | 1991-10-25 | Explosive cable connector |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2054115A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2127040A1 (en) * | 2007-03-12 | 2009-12-02 | Fci | Implosion connector and method for use with transmission line conductors comprising composite cores |
| US7947905B2 (en) | 2003-04-04 | 2011-05-24 | Hubbell Incorporated | Method and apparatus for joining ends of wires and the like |
| WO2017176570A1 (en) * | 2016-04-05 | 2017-10-12 | Afl Telecommunications Llc | Cable connector accessory assemblies and methods for connecting cables to cable connector accessories |
-
1991
- 1991-10-25 CA CA 2054115 patent/CA2054115A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7947905B2 (en) | 2003-04-04 | 2011-05-24 | Hubbell Incorporated | Method and apparatus for joining ends of wires and the like |
| EP2127040A1 (en) * | 2007-03-12 | 2009-12-02 | Fci | Implosion connector and method for use with transmission line conductors comprising composite cores |
| US8246393B2 (en) | 2007-03-12 | 2012-08-21 | Hubbell Incorporated | Implosion connector and method for use with transmission line conductors comprising composite cores |
| EP2127040A4 (en) * | 2007-03-12 | 2014-08-06 | Hubbell Inc | Implosion connector and method for use with transmission line conductors comprising composite cores |
| WO2017176570A1 (en) * | 2016-04-05 | 2017-10-12 | Afl Telecommunications Llc | Cable connector accessory assemblies and methods for connecting cables to cable connector accessories |
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