WO2004029003A2

WO2004029003A2 - Detonation junction for blasting networks

Info

Publication number: WO2004029003A2
Application number: PCT/US2003/029386
Authority: WO
Inventors: John O'brien
Original assignee: Union Espanola De Explosivos-Mining Services International S.A.
Priority date: 2002-09-25
Filing date: 2003-09-18
Publication date: 2004-04-08
Also published as: AU2003276899A8; US20040055494A1; AU2003276899A1; WO2004029003A3

Abstract

A detonator junction for use in a blasting network is disclosed. A body of the detonator junction includes a chamber for receiving a detonator. A retaining member, attached to the body, creates a slot for retaining one or more transmission lines proximate an explosive output region of a detonator disposed in the chamber. A limiting member, attached to the retaining member, traverses an imaginary longitudinal extension of the slot and limits inadvertent removal of transmission lines from the slot. A clip may interlock with the detonator, which in turn may be locked into the chamber to ensure secure and proper placement of the detonator in the chamber. When the detonator is activated a transmission signal is initiated in transmission lines disposed within the slot.

Description

DETONATOR JUNCTION FOR BLASTING NETWORKS

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to blasting techniques. More specifically, the present invention relates to a detonator junction for use in a blast initiation system.

2. Technical Background The detonation of multiple explosives is common in both mining and construction applications. However, simultaneous detonation of a large quantity of explosives can result in excessive ground vibrations and can be counterproductive. Thus, initiating explosives in successive rows, layers, or groups can minimize these problems and more economically achieve the specific objectives of the explosions, hi quarry blasting, for instance, sequential delays between explosions must be controlled within milliseconds to achieve desired objectives. Also, in construction, sequential blasts may be used to move or loosen large amounts of rock or earth.

Both pyrotechnic and electrical explosives may be used for sequential blasting. However, in many circumstances, electrical explosives are dangerous because a stray induced charge may accidentally set off an electrical explosive, injuring individuals near the explosive. Because of this danger, in mining and construction applications, pyrotechnic explosives are frequently used instead of electrical explosives.

Historically, the timing of the blasts was controlled by the length of the textile wrapped black powder fuses leading to each explosive. Typically, these fuses burned at a rate of about 120 seconds per yard. A longer fuse, of course, deferred detonation of an attached explosive for a longer period of time from lighting the fuse, while a shorter fuse produced an earlier explosion. Multiple fuses could be tied or otherwise joined together to form a network of explosives. The network of explosives could be initiated by lighting a single fuse connected to the network.

Later, textile wrapped fuses included a high energy explosive core such as PETN (Pentaerythritol Tetranitrate). These fuses can burn at about a rate of about 7000 meters per second. While the burn rate is much faster, these fuses suffered from a number of different problems. For instance, rain, snow, or other inclement weather could limit the effectiveness of the exposed fuses. Additionally, the high energy explosive core creates a loud noise during incineration. The noise posed a nuisance and perhaps a health risk to workers and adjacent populated areas. To minimize these problems, the industry has adopted the use of shock wave transmission lines, also referred to as "shock tubes". The shock tube is a hollow tube containing a combustible or reactive material, such as HJJMX (Cyclotetramethylenetetranitramine) and aluminum. Igniting the combustible material inside the tube initiates a shock wave within the transmission lines. The shock wave travels at about 2000 meters per second. The shock wave is similar to a dust explosion and will initiate explosives coupled to the transmission lines. These transmission lines may also be referred to as "shock tubes", detonator cord, or percussion primer.

In contrast to conventional fuses, this type of transmission line may be virtually noiseless and produces no side blasts. Moreover, although combustion of the combustible material may be initiated at an open end of the tube with a percussion shock wave or source of heat, initiating combustion by using a shock wave provides greater flexibility and minimizes the risk of contamination of the combustible material. As a consequence, a detonator or percussion primer that produces a small explosion or other source of a high pressure heat shock wave in response to receipt of a shock wave may be positioned proximate an outgoing transmission line or lines. The detonator may be coupled to an incoming transmission line. Thus, when a shock wave is received at the detonator via the incoming transmission line, a small detonation is produced by the detonator and the resulting shock wave passes through the wall of the transmission line and initiates a thermal shock wave within the outgoing transmission line or lines.

Detonator blocks have been developed for initiating a thermal shock waves in one or more outgoing transmission lines. These detonator blocks typically have a structure for receiving a detonator and a structure for receiving and retaining transmission lines. When positioned in the detonator block, a detonator output region of the detonator is situated proximate transmission lines retained in the detonator block. As explained above, upon receipt of a shock wave, the detonator generates a shock wave which is transmitted to the outgoing transmission lines, initiating a thermal shock wave within the lines.

These detonator blocks, however, may suffer from a number of drawbacks. Blasting networks can be extremely complex and timing is, obviously, of critical importance. As such, it is important that the detonator blocks securely retain inserted transmission lines. Otherwise, transmission lines can inadvertently be removed from the appropriate detonator blocks, potentially disrupting the entire blast sequence. Moreover, it may be difficult or time-consuming to locate the detonator blocks from which the transmission lines have been inadvertently removed. Worse still, such errors may go undetected.

Another problem relating to conventional detonator blocks is properly positioning detonators within the detonator blocks. Generally, the detonator has a low output to minimize shrapnel on the surface of a blasting hole. For example, the output charge may be produced using lead azide. If such a detonator is not correctly positioned within a detonator block, the detonator may be too far from the transmission lines to impart a shock wave in the outgoing transmission lines. Also, if the detonator is not securely fastened within the detonator block, the detonator may become separated from the detonator block, again disrupting the blasting pattern. Furthermore, it is often difficult for a worker to determine when a detonator is properly positioned and securely fastened within a detonator block.

Thus, it would be an advancement in the art to provide a detonator block that limits inadvertent removal of transmission lines from the detonator block. It would be a further advancement in the art to provide a detonator block with a superior mechanism for retaining and correctly positioning a detonator within the detonator block.

Such a device is disclosed and claimed herein.

SUMMARY OF THE INVENTION The apparatus and methods of the present invention have been developed in response to the present state-of-the-art, and, in particular, in response to problems and needs in the art that have not yet been fully resolved by currently available blasting networks. The present invention provides an apparatus for enhancing the effectiveness of blasting systems. To achieve the foregoing, and in accordance with the invention as embodied and broadly described in the preferred embodiment, a detonator junction for use in a network of explosives is disclosed.

The detonator junction may include a body having an interior surface defining a chamber for receiving a detonator. The body may be configured in various shapes. The shape of the body may be governed by the shape of the detonator to be received in the chamber. For example, if the detonator is an elongated cylinder, the body may also be elongated in shape. In certain embodiments, the body may be sized and shaped to facilitate handling by a worker wearing gloves during coupling of the detonator junction to a detonator and one or more transmission lines. As will be understood by those skilled in the art, the body may be made from various types of materials, including plastics. Ideally, the body is resiliently deformable such that it can absorb any scattered shrapnel when the detonator disposed therein is activated. Also, the body should be made from a material that will retain its shape and resiliency in a wide variety of climates and temperature ranges. Although detonators may be configured in various shapes, detonators may be and are usually embodied in a cylindrical shape. An explosive material may be disposed within an output region of the detonator. Low-energy detonators produce smaller explosions, less shrapnel, and are not as noisy as conventional detonators. The low energy detonators may be used to provide a pyrotechnic delay to accomplish a desired timing precision in an explosives network. Detonators are known to those skilled in the art.

The detonator junction may include a retaining member attached to the body. The retaining member extends away from the body and then runs along a side of the body. Thus, the retaining member and body define a slot for retaining one or more transmission lines within the detonator junction. More specifically, the slot may retain one or more transmission lines proximate the output region of a detonator disposed within the detonator junction. As stated above, application of heat to a transmission line initiates a thermal shock wave within the transmission line.

The body and the retaining member may each comprise a substantially planar surface that defines the slot. Of course, the "substantially planar surface" may include minor deviations from a perfectly planar surface. For instance, the body and retaining member may include opposing arcuate indentations for positioning the transmission lines at specific sites within the slot. The detonator junction may also include a limiting member. The limiting member is attached to the retaining member. The limiting member may be attached to or integrally formed with the retaining member and/or body. The limiting member traverses an imaginary longitudinal extension of the slot. Thus, the limiting member covers a portion of the slot and limits insertion and removal of a transmission line from the slot. Additionally, the limiting member and the body may define a channel through which a transmission line passes before insertion into the slot.

The channel or the portion of the channel adjacent to the slot is more narrow than the diameter of a transmission line. Therefore, the limiting member serves to retain transmission lines within the slot.

The detonator junction may optionally include a protrusion. The protrusion may be attached to or be integrally formed with the body, retaining member, and/or limiting member. The protrusion is shaped and positioned to restrict movement of a transmission line from the slot into the channel. The protrusion may be embodied in a number of different configurations to serve this purpose, as will be understood by those skilled in the art. Also, the protrusion may define at least a portion of the channel. For instance, the protrusion may include an arcuate extension along the channel protruding up into the slot.

Transmission lines and detonator junctions may be assembled into a complex network to form a specific blasting pattern. If one of the transmission lines is inadvertently dislodged from a detonator junction, the error may go undetected, destroying at least one aspect of the blasting pattern. Alternatively, if the error is detected, it may require a great deal of time to determine which detonator junction the transmission line should be inserted into. The limiting member and/or protrusion securely retain transmission lines within the slot and make inadvertent dislodgment of the lines far less likely.

The detonator junction may also optionally include a clip. The clip is shaped to interlock with the detonator. A U-shaped opening of the clip may interlock with the detonator. For instance, the detonator may include a crimp for receiving the clip. The crimp serves to couple the detonator to a transmission line. The crimp includes a relatively wider portion of the detonator between two grooves which are relatively narrower portions of the detonator. The U-shaped opening of the clip may include ridges for mating with the grooves of the detonator and valleys for mating with the wider portion of the detonator, hi one embodiment, the clip is sized and shaped such that the clip snaps around the crimp to engage the detonator. The clip may be biased to engage the detonator within an opening of the clip. Of course, those skilled in the art will understand that various structural configurations may be used to interlock the detonator and the clip.

The interior surface of the body may further define a mating interface within the chamber. The mating interface is shaped to receive and lock the clip and an interlocked detonator in the chamber. More specifically, the clip includes arms that are resiliently deformable. The mating interface includes an arm chamber for receiving the arms on the clip. Openings may be disposed in opposing sides of the arm chamber. A detent is disposed on each of the arms. A distance between the outer edges of the detents is slightly less than a distance between opposing sides of the arm chamber.

Thus, when the arms are inserted into the arm chamber, the outer edges of the detents contact the arm chamber, deforming the arms towards each other. When the detents reach the openings, the detents are pushed outwardly into the openings by the resilient force of the arms, locking the clip and an interlocked detonator in the chamber.

Use of a clip provides important advantages over prior techniques for positioning the detonator in the chamber. If the detonator is not correctly inserted and locked into the chamber, it may become dislodged or may not transmit a thermal shock wave to the associated transmission lines. The detonator junction makes such a scenario far less likely than conventional devices. The detonator junction enables a user to look at the openings and easily determine whether the detents are securely and properly positioned therein. Also, there is often a "snapping" sound or click when the detents are correctly positioned in the openings, as the arms strike the arm chamber. The "snapping" sound provides the user with an additional indication of proper placement of the detonator in the chamber.

A detonator junction may be used in the following manner. A thermal shock wave is initiated in a transmission line coupled to a detonator disposed within a detonator junction. Again, a thermal shock wave may be initiated by applying heat to either an end of a transmission line or a side of the transmission line. The thermal shock wave is a combustion or reaction front (where combustion or reaction is occurring) within the tubing of a transmission line.

When the combustion front reaches the detonator disposed within the detonator junction, the explosive output region within the detonator is activated. The resulting shock wave is then transferred through the walls of each fransmission line disposed within the slot of the detonator junction, initiating a thermal shock wave within each such transmission line. Thus, thermal shock waves are propagated throughout a blasting network containing one or more detonator junctions.

When a thermal shock wave is received at an explosive such as AJNFO (Ammonium Nitrate and Fuel Oil) or dynamite, the explosive is detonated. Again, the purpose of the blasting network is to detonate explosives in a timed sequence for various purposes, including both mining and construction.

In view of the foregoing, the detonator junction provides advantages over conventional devices. The limiting member assists in maintaining transmission lines within the slot to limit inadvertent dislodgment of transmission lines from a detonator junction. Furthermore, the clip helps to properly position and maintain the detonator within the channel so that the low energy detonator is correctly positioned with respect to the transmission lines.

These and other advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the advantages and features of the invention are obtained, a more particular description of the invention summarized above will be rendered by reference to the appended drawings. Understanding that these drawings illustrate only selected embodiments of the invention and are not therefore to be considered limiting in scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: Figure 1 is a partially cut-away perspective view of a detonator junction that includes an exploded view of a detonator and a clip;

Figure 2a is a top plan view of a detonator disposed within a clip; Figure 2b is a front plan view of a detonator disposed within a clip;

Figure 3a is a bottom view of a body for a detonator junction, illustrating a chamber and mating interface for a clip;

Figure 3b is a cross-sectional view of a body for a detonator junction taken across line 3b,3c-3b,3c of Figure 3a;

Figure 3c is a cross-sectional view of a body for a detonator junction taken across line 3b,3c-3b,3c of Figure 3a, including with a cross-sectional view of a clip and a perspective view of a detonator disposed therein;

Figure 4 is a cross-sectional view of a detonator junction, including a cross- sectional view of a clip and a perspective view of a detonator;

Figure 5 is a plan view of a blasting network using detonator junctions and transmission lines; and

Figure 6 is a plan view of an alternative blasting network using detonator junctions and transmission lines. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the invention are now described with reference to Figures 1-5. The members of the present invention, as generally described and illustrated in the Figures, may be implemented in a wide variety of configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in the Figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of presently preferred embodiments of the invention.

Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to convey a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. Figure 1 is a cutaway perspective view of a detonator junction 12 including an exploded view of a detonator 14 and a clip 16 for use in a network of explosives. The detonator junction 12 may include a body 18. As will be understood by those skilled in the art, the body 18 may be made from various types of materials, including plastics. Ideally, the body 18 is resiliently deformable such that it can absorb any scattered shrapnel when the detonator 14 disposed therein is activated. Also, the body 18 should be made from a material that will retain its shape and resiliency in a wide variety of climates and temperature ranges.

The body 18 may have an interior surface 20. The interior surface 20 defines a chamber 22 shaped to receive a detonator 14. The chamber 22 may be shaped to generally fit the detonator 14 that the chamber 22 is designed to receive.

The detonator 14 has an explosive output region 24, which is activated upon receipt of a thermal shock wave from an incoming transmission line 26a. The explosive output region 24 may include an explosive and is understood by those skilled in the art. Although detonators 14 may be configured in various shapes, they may be and are usually embodied in a cylindrical shape, as illustrated. In alternative embodiments, the detonator 14 is manufactured with a built-in pyrotechnic delay.

As stated before, transmission lines 26 may include hollow tubing with a reactive or combustible material (e.g., HMX and aluminum) disposed therein. A thermal shock wave (a reaction or combustion front) within a transmission line 26 may be initiated by applying a shock wave to an open end or a side of a transmission line 26. Also, low-energy detonators 14 and transmission lines 26, which are known to those skilled in the art, may be used to reduce the noise accompanying propagation of a thermal shock wave through a network of explosives. Detonators 14 and transmission lines 26 are made by various companies, including Ensign-Bickford Company of Simsbury, CT, Orica of Melbourne, Australia, and Dyno Nobel of Oslo, Norway.

The detonator junction 12 may include a retaining member 28. The retaining member 28 may be attached to or integrally formed with the body 18. The retaining member 28 extends away from the body 18 and then runs along a side of the body 18 to form a slot 30. The slot 30 retains one or more transmission lines 26b within the detonator junction 12. In one embodiment, up to four transmission lines 26 may be placed within the slot 30. Of course, a detonator 14 with a larger or wider explosive output region 24 would enable construction of a detonator junction 12 in which more than four fransmission lines 26 could be positioned and still allow proper initiation of a thermal shock wave within each of the lines 26.

The body 18 and the retaining member 28 may each comprise a substantially planar surface 32a-b that defines the slot 30. The "substantially planar surface" 32a-b may include minor deviations from a perfectly planar surface. Those deviations may include both manufacturing defects and predetermined deviations. For instance, the retaining member 28 and body 18 may include opposing arcuate indentations 34 for positioning the transmission lines 26 at specific sites within the slot 30.

In addition, the substantially planar surface 32a of the body 18 and the substantially planar surface 32b of the retaining member 28 may be generally parallel to each other, as illustrated in Figures 1 and 4. This means that a plane that generally defines the substantially planar surface 32b of the retaining member 28 is parallel to a plane that generally defines the substantially planar surface 32a of the body 18.

The detonator junction 12 may also include a limiting member 36. The limiting member 36 may be attached to or integrally formed with the retaining member 28 and/or body 18. The limiting member 36 traverses an imaginary longitudinal extension 38 of the slot 30 and limits insertion and removal of a transmission line 26 from the slot 30. Additionally, the limiting member 36 and the body 18 may define a channel 40 through which a transmission line 26 passes before insertion into the slot 30.

The portion 42 of the channel 40 adjacent to the slot 30 is more narrow than the diameter 44 of the transmission line 26. Thus, the limiting member 36 serves the purpose of retaining a transmission line 26 within the slot 30. Also, the limiting member 36 controls the force required to insert transmission lines 26 into the slot 30.

Transmission lines 26 and junctions 12 may be assembled into a complex network to form a specific blasting pattern (see, e.g., Figure 5). If one of the transmission lines 26 is inadvertently dislodged from a detonator junction 12, the error may go undetected, destroying at least one aspect of the blasting pattern. Alternatively, if the error is detected, it may require a great deal of time, to determine which detonator junction 12 the transmission line 26 should be inserted into. The limiting member 36 securely retains transmission lines 26 within the slot 30 and makes inadvertent dislodgment of the lines 26 far less likely.

The detonator junction 12 may optionally include a protrusion 46. The protrusion 46 may be attached to or be integrally formed with the body 18, retaining member 28, and/or limiting member 36. The protrusion 46 is shaped and positioned to restrict movement of a transmission line 26 from the slot 30 into the channel 40. As illustrated, the protrusion 46 is arcuate in shape. The protrusion 46 may be embodied in a number of different configurations to serve this purpose, as will be understood by those skilled in the art. Also, the protrusion 46 may define at least a portion of the channel 40. The protrusion 46 provides a safeguard that, in addition to the limiting member 36, serves to avoid inadvertent dislodgment of the transmission lines 26.

As shown in Figure 4, when the detonator 14 is disposed in the chamber 22, the explosive output region 24 is positioned proximate outgoing transmission lines 26b to allow a shock wave to pass through the tubing of the outgoing transmission lines 26b and initiate a thermal shock wave within the outgoing transmission lines 26b upon activation of the explosive output region 24. As used in this application, having the detonator 14 disposed in the chamber 22 does not mean that the detonator 14 is entirely disposed in the chamber 22, but, instead, means that the detonator 14 is properly positioned in the chamber 22.

Referring once again to Figure 1, the detonator junction 12 may also optionally include a clip 16. The clip 16 is shaped to interlock with the detonator 14. A U-shaped opening 48 of the clip 16 may interlock with a crimp 50 disposed on the detonator 14 and retain a fixed position relative to the detonator 14. The clip 16 may interlock with conventional detonators 14. As such, the detonator 14 does not need to be specially manufactured to interlock with the clip 16. One embodiment of the clip 16 will be discussed in further detail in connection with Figures 2a-b.

The interior surface 20 of the body 18 may further define a mating interface 54 within the chamber 22. The mating interface 54 is shaped to receive and lock the clip 16 and an interlocked detonator 14 in the chamber 22. More specifically, the mating interface 54 includes a main chamber 56 for receiving the main portion 58 of the clip 16, a lip chamber 60 for receiving a lip 62 of the clip 16, and an arm chamber 64 for receiving arms 66 on the clip 16. A detent 68 is disposed on each of the arms 66. As will be explained in greater detail in connection with Figures 3a-c, the arms 66 are resiliently deformable such that the detents 68 may be disposed in openings 70 in the body 18 to lock the clip 16 and an interlocked detonator 14 in the chamber 22.

Figure 2a is a top plan view and Figure 2b is a front plan view of a clip 16 interlocked with a detonator 14. As stated before, the clip 16 includes a U-shaped opening 48 that is configured to interlock with a crimp 50 on the detonator 14. Again, the clip 16 includes arms 66 with detents 68 disposed thereon for mating with the openings 70 in the mating interface 54 of the body 18. As illustrated, the clip 16 includes ridges 72 to mate with grooves of the crimp 50 of the detonator 14 and valleys 74 to mate with a relatively wider portion of the detonator 14. The ridges 72 and valleys 74 of the clip 16 tightly conform to the crimp 50 of the detonator 14 providing a secure fit between the clip 16 and detonator 14. Preferably, when properly engaged the detonator 14 "snaps" into the clip 16. Of course, as will be understood by those skilled in the art, both the clip 16 and detonator 14 may be configured in various shapes to interlock.

As also will be understood by those skilled in the art, the clip 16 may be made from various types of materials, including plastics. As with the body 18, the material should be resiliently deformable in a wide variety of temperature ranges and conditions. Figures 3a-c provide further illustration of the interaction between the clip 16 and the mating interface 54. Specifically, Figure 3a is a bottom plan view of the body 18 that illustrates the mating interface 54 and chamber 22. Figure 3b is a cross- sectional view on line 3b,3c-3b,3c of the mating interface 54 and body 18, while Figure 3c is a cross-sectional view on line 3b,3c-3b,3c of the mating interface 54 and body 18, including a cross-sectional view of the clip 16 and a perspective view of an interlocked detonator 14 disposed in the chamber 22.

As stated above, an interior surface 20 defines a chamber 22 and a mating interface 54 within the body 18. The mating interface 54 is configured to receive and lock into place a clip 16 and an interlocked detonator 14. More specifically, the mating interface 54 includes a main chamber 56 for receiving the main portion 58 of the clip 16, a lip chamber 60 for receiving the lip 62 of the clip 16, and the arm chamber 64 for receiving the arms 66 of the clip 16. The openings 70 are disposed just above the arm chamber 64. The distance 76 between the outer edges of the detents 68 of the clip 16 is slightly greater than the distance 78 between opposing sides of the arm chamber 64 just below the openings 70. Again, the arms 66 are resiliently deformable. Thus, as explained more broadly above, when the clip 16 is inserted into the mating interface 54, the arms 66 of the clip 16 are positioned within the arm chamber 64, the detents 68 contact opposing sides of the arm chamber 64, and the arms 66 deform towards each other. When the detents 68 reach the openings 70, the arms 66 move apart, pushing the detents 68 in the openings 70 and locking the clip 16 and an interlocked detonator 14 in the chamber 22. Of course, those skilled in the art will recognize that the clip 16 and mating interface 54 may be configured in various ways to secure the detonator 14 in the chamber 22. The illustrated embodiment is merely exemplary.

Use of a clip 16 provides important advantages over prior techniques for positioning the detonator 14 in the chamber 22. If the detonator 14 is not correctly inserted and locked into the chamber 22, it may become dislodged or may not transmit a thermal shock wave to the associated transmission lines 26. The detonator junction 12 makes such a scenario far less likely than conventional devices. The detonator junction 12 enables a user to look at the openings 70 and easily determine whether the detents 68 are securely and properly positioned therein. In addition, there is often a "snapping" sound or click when the detents 68 are correctly positioned in the openings 70, as the arms 66 strike the arm chamber 64. The "snapping" sound provides the user with an additional indication of proper placement of the detonator 14 within the chamber 22.

Figure 4 is a cross-sectional view of a detonator junction 12. A cross-sectional view of a clip 16 and a perspective view of an interlocked detonator 14 disposed within the chamber 22 are illustrated in this Figure. The explosive output region 24 of the detonator 14 is disposed proximate transmission lines 26b positioned within the slot 30. As such, when the explosive output region 24 is activated, a shock wave is transmitted through the tubes into the combustible material within the transmission lines 26. In response thereto, a thermal shock wave is initiated in each of the transmission lines 26b disposed within the slot 30.

As illustrated in Figure 4, the chamber 22 opens up into the slot 30, allowing for unimpeded transmission of explosive output from the explosive output region 24 of the detonator 14 to the fransmission lines 26b. Of course, in alternative embodiments, although a barrier (not illustrated) may separate the chamber 22 and the slot 30, the shock wave may still be transferred from the explosive output region 24 to transmission lines 26b disposed within the slot 30 sufficient to initiate a thermal shock wave within the transmission lines 26b.

The channel 40 created by the limiting member 36 is more narrow than the transmission lines 26b, restricting exit of the transmission lines 26b from the slot 30 into the channel 40. Moreover, the channel 40 is disposed at an angle with respect to the slot 30, again making it more difficult for transmission lines 26b to inadvertently be removed from the slot 30. Stated more precisely, a longitudinal axis 80 of the slot 30 is disposed at an angle with respect to (is not parallel to) a longitudinal axis 82 of the channel 40.

A combination of the retaining and limiting members 28, 36 may be referred to as a restraint mechanism 84. A distance between the protrusion 46 and restraint mechanism 84 is more narrow than the diameter 44 of the transmission line 26b such that passage of transmission lines 26b through this area 86 into the channel 40 is limited. In embodiments with or without protrusions 46, the channel 40 may be more narrow than a diameter 44 of the transmission line 26b, again limiting movement of transmission lines 26b through the channel 40. Thus, the restraint mechanism 84 limits removal of transmission lines 26b from the slot 30 through the channel 40. Transmission lines 26b may be inserted into the slot 30 through the channel 40. To this end, the restraint mechanism 84 and/or transmission lines 26b may be resiliently deformable. Thus, the restraint mechanism 84 and/or the transmission lines 26b may deform slightly when transmission lines 26 pass from the channel 40, through the area 86. between the protrusion 46 and the restraint mechanism 84, and into the slot 30. Thus, the restraint mechanism 84 limits insertion of transmission lines 26b through the channel 40 into the slot 30.

Figure 5 is a plan view of a blasting network 88 using detonator junctions 12a- c and fransmission lines 26a-i for timed initiation of explosive charges 90a-f. Of course, the illustrated network 88 is only one example of sequential blasting. Those skilled in the art will recognize that blasting networks 88 may be used in a wide variety of configurations and circumstances, such as mining and construction. One advantage of the detonator junction 12a-c is its flexibility and the ease with which a blasting network 88 may be assembled. The explosives 90a-f used in connection with the detonator junction 12a-c are initiated by a high strength detonator (not shown), as opposed to surface connections which use low output detonators 14.

As illustrated in Figure 5, explosives 90a-f, coupled to the network 88, are disposed within boreholes 92a-b in the earth. Typically, to most efficiently break up rock, the explosives 90 are positioned at different at different levels within a bore hole 92. This process may be referred to as "decking." For example in bore hole 92a, three explosives 90a-c are positioned to cover about a third of the bore hole 92a. Such positioning allows for use of less explosive 90a-c and control of the timing of the explosives 90a-f. Timing the detonation of such explosives 90a-f is critical to prevent one explosive 90a-f from influencing, or detonating, an adjacent explosive 90a-f. Although only one explosive 90a-f is illustrated at each level, or deck, in alternative embodiments, multiple explosives 90a-f may be placed on each deck. Additionally, each explosive may be separated by a timing delay. For example, explosive 90a may detonate before explosive 90b and explosive 90b may detonate before explosive 90c.

Each deck, or level of explosives 90a-f, may be separated by a layer of stemming 96. Generally, stemming 96 is sized, crushed stone, such as drill cuttings. Layers of air may also serve as stemming 96. Stemming 96 is strategically placed to produce the desired blasting effects from the explosives 90a-f.

The network 88 illustrated in Figure 5 may be used in the following manner. A thermal shock wave is transmitted to a first detonator junction 12a via a first transmission line 26a. Within the first detonator junction 12a, the thermal shock wave is received at a detonator 14. The detonator 14 includes an explosive output region 24, which is activated upon receipt of a thermal shock wave.

Within the detonator junction 12a, the explosive output region 24 is disposed proximate a second and a third transmission line 26b-c. The shock wave generated by the detonator 14 simultaneously initiates a thermal shock wave within the second and third transmission lines 26b-c. Each of the outgoing transmission lines 26b-i may be sealed at one end to prevent contamination.

The thermal shock wave in the second transmission line 26b is received at a second detonator junction 12b. Thereafter, the explosive output region 24 in the second detonator junction 12b is activated initiating a thermal shock wave within the fourth, fifth, and sixth transmission lines 26d-f. Here, the explosives 90a-c will be detonated in a sequence according to the length of the transmission line 26d-f between the second detonator junction 12b and each of the explosives 90a-c. The explosives 90a-c coupled to shorter transmission lines 26d-f will be detonated first. The thermal shock wave transmitted along the third transmission line 26c will initiate a thermal shock wave within the seventh, eighth, and ninth transmission lines 26g-i at the third detonator junction 12c. Accordingly, the fourth, fifth and sixth explosives 90d-f will be activated in that sequence.

The blasting network 88 of Figure 5 is one of many different configurations which may be used with detonator junctions 12. h Figure 5, the detonator junctions 12 are connected in parallel. The first detonator junction 12a is connected by transmission lines 26 directly to the second detonator junction 12b and the third detonator junction 12c. When the detonator 14 in the first detonator junction 12a detonates, a shock wave is initiated in both transmission line 26b and transmission line 26c almost simultaneously. The shock wave then continues to propagate and pass as described above in relation to Figure 5. The configuration of detonator junctions 12a-c in Figure 5 may be referred to as a parallel blasting network 88.

Referring now to Figure 6, alternatively, detonator junctions 12 may be used to configure a serial blasting network 98, one in which the shock wave passes in series from one detonator junction 12 to the next. Figure 6 includes the same elements as in Figure 5, except that the network connection between detonator junctions 12 is different.

Once a shock wave is initiated in the first detonator transmission line 26a, the shock wave is communicated, in the manner described above, from the detonator 14 in the first detonator junction 12a to the transmission lines 26d-f coupled to the explosives 90a-c and to the transmission line 26b of the second detonator junction 12b. This process of communicating the shock wave from the first detonator junction 12a to the second detonator junction 12b may continue for as many detonator junctions 12c-e connected in series in the serial blasting network 98. Of course detonator junctions 12 may be used to create a mixed blasting network (not shown) in which some detonator junctions 12 are connected in series and some detonator junctions 12 are connected in parallel.

In view of the foregoing, the detonator junction 12 provides advantages over conventional devices. The limiting member 36 assists in maintaining transmission lines 26 within the slot 30 to limit inadvertent removal of transmission lines 26 from a detonator junction 12. Furthermore, the clip 16 helps to maintain and properly position a detonator 14 within the channel 40 to insure proper positioning of the detonator 14 relative to transmission lines 26 within the slot 30.

Furthermore, the present invention may be embodied in other specific forms without departing from its scope or essential characteristics. The described embodiments are to be considered in all respects only illustrative, not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

CLAIMS:

1. A detonator junction for use in a blasting network, the detonator junction comprising: a body having an interior surface that defines a chamber shaped to receive a detonator; a retaining member attached to the body, wherein the retaining member and body define a slot for retaining at least one transmission line; and a limiting member, attached to the retaining member, that traverses an imaginary longitudinal extension of the slot to limit insertion and removal of a fransmission line from the slot.

2. The detonator junction as defined in claim 1, wherein the body, retaining member, and limiting member are integrally formed.

3. The detonator junction as defined in claim 1, wherein the body and the retaining member each comprise a substantially planar surface that defines the slot.

4. The detonator junction as defined in claim 1 , further comprising a clip shaped to interlock with the detonator, wherein the interior surface of the body further defines a mating interface within the chamber, the mating interface being shaped to receive and lock the clip and an interlocked detonator in the chamber.

5. The detonator junction as defined in claim 1 , wherein the body further comprises a protrusion shaped to restrict movement of a transmission line from the slot into the channel.

6. The detonator junction as defined in claim 5, wherein the protrusion is arcuate in shape.

7. The detonator junction as defined in claim 6, wherein the limiting member and the body define a channel through which a transmission line passes before insertion into the slot.

8. The detonator junction as defined in claim 7, wherein the protrusion defines at least a portion of the channel.

9. The detonator junction as defined in claim 7, wherein a longitudinal axis of the slot is disposed at an angle with respect to a longitudinal axis of the channel.

10. A detonator junction for use in a blasting network, the junction comprising: a body having an interior surface that defines a chamber shaped to receive a detonator having an explosive output region; a retaining member attached to the body, wherein the retaining member and body define a slot for retaining at least one fransmission line proximate the explosive output region of the detonator when the detonator is disposed in the chamber; and a limiting member, attached to the retaining member, that traverses an imaginary longitudinal extension of the slot, wherein the limiting member and the body define a channel through which a transmission line passes before insertion into the slot.

11. The detonator junction as defined in claim 10, wherein the body, retaining member, and limiting member are integrally formed.

12. The detonator junction as defined in claim 10, wherein the body and the retaining member each comprise a substantially planar surface that defines the slot.

13. The detonator junction as defined in claim 10, further comprising a clip shaped to interlock with the detonator, wherein the interior surface of the body further defines a mating interface within the chamber, the mating interface being shaped to receive and lock the clip and an interlocked detonator in the chamber.

14. The detonator junction as defined in claim 10, wherein the body further comprises a protrusion shaped to restrict movement of a transmission line from the slot into the channel.

15. The detonator junction as defined in claim 14, wherein the protrusion is arcuate in shape.

16. The detonator junction as defined in claim 15, wherein the protrusion defines at least a portion of the channel.

17. The detonator junction as defined in claim 10, wherein a longitudinal axis of the slot is disposed at an angle with respect to a longitudinal axis of the channel.

18. A detonator junction for use in a blasting network, the junction comprising: a body having an interior surface that defines a chamber shaped to receive the detonator having an explosive output region; a retaining member attached to the body, wherein the retaining member and body define a slot for retaining at least one transmission line proximate the explosive output region of the detonator when the detonator is disposed in the chamber; a limiting member, attached to the retaining member, that traverses an imaginary longitudinal extension of the slot, wherein the limiting member and the body define a channel through which a transmission line passes before insertion into the slot; a protrusion disposed on the body and shaped to restrict movement of a transmission line from the slot into the channel; and a clip shaped to interlock with the detonator, wherein the interior surface of the body further defines a mating interface within the chamber, the mating interface being shaped to receive and lock the clip and an interlocked detonator in the chamber.

19. The detonator junction as defined in claim 18, wherein the body and the retaining member each comprise a substantially planar surface that defines the slot.

20. The detonator junction as defined in claim 19, wherein the substantially planar surface of the retaining member and the substantially planar surface of the body are generally parallel to each other.

21. The detonator junction as defined in claim 18, wherein the protrusion is arcuate in shape.

22. The detonator junction as defined in claim 21, wherein the protrusion defines at least a portion of the channel.

23. The detonator junction as defined in claim 18, wherein a longitudinal axis of the slot is disposed at an angle with respect to a longitudinal axis of the channel.

24. The detonator junction as defined in claim 18, wherein the body, retaining member, limiting member, and protrusion are integrally formed.

25. A method of transmitting a thermal shock wave in a blasting network using a detonator junction, the method comprising the steps of: receiving a first thermal shock wave at a detonator disposed within a chamber defined by an interior surface of a body of a detonator junction, the detonator having a explosive output region, the detonator junction having a retaining member attached to the body, and a limiting member attached to the retaining member, wherein the body and retaining member define a slot for receiving at least one transmission line, and wherein the retaining member traverses a longitudinal extension of the slot to limit insertion and removal of a transmission line from the slot; activating an explosive output region of the detonator in response to receipt of the first thermal shock wave; initiating a second thermal shock wave within each transmission line disposed in the slot in response to activation of the explosive output region; receiving the second thermal shock wave at an explosive coupled to one of the transmission lines disposed in the slot; and detonating the explosive in response to receipt of the second thermal shock wave at the explosive.

26. The method as defined in claim 25, wherein the limiting member and the body define a channel through which a transmission line passes before insertion into the slot.

27. The method as defined in claim 26, wherein the protrusion defines at least a portion of the channel.

28. The method as defined in claim 27, wherein a longitudinal axis of the slot is disposed at an angle with respect to a longitudinal axis of the channel.