U.S. patent application number 10/254307 was filed with the patent office on 2004-03-25 for detonator junction for blasting networks.
Invention is credited to O'Brien, John P..
Application Number | 20040055494 10/254307 |
Document ID | / |
Family ID | 31993327 |
Filed Date | 2004-03-25 |
United States Patent
Application |
20040055494 |
Kind Code |
A1 |
O'Brien, John P. |
March 25, 2004 |
Detonator junction for blasting networks
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.
Inventors: |
O'Brien, John P.;
(Pawcatuck, CT) |
Correspondence
Address: |
MADSON & METCALF
GATEWAY TOWER WEST
SUITE 900
15 WEST SOUTH TEMPLE
SALT LAKE CITY
UT
84101
|
Family ID: |
31993327 |
Appl. No.: |
10/254307 |
Filed: |
September 25, 2002 |
Current U.S.
Class: |
102/275.12 |
Current CPC
Class: |
C06C 5/06 20130101; F42D
1/043 20130101 |
Class at
Publication: |
102/275.12 |
International
Class: |
C06C 005/06 |
Claims
What is claimed and desired to be secured by United States Letters
Patent is:
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 transmission 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
transmission 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.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to blasting techniques. More
specifically, the present invention relates to a detonator junction
for use in a blast initiation system.
[0003] 2. Technical Background
[0004] 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. In 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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 HMX (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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] Such a device is disclosed and claimed herein.
SUMMARY OF THE INVENTION
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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. In 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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 transmission 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.
[0032] When a thermal shock wave is received at an explosive such
as ANFO (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.
[0033] 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.
[0034] 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
[0035] 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:
[0036] FIG. 1 is a partially cut-away perspective view of a
detonator junction that includes an exploded view of a detonator
and a clip;
[0037] FIG. 2a is a top plan view of a detonator disposed within a
clip;
[0038] FIG. 2b is a front plan view of a detonator disposed within
a clip;
[0039] FIG. 3a is a bottom view of a body for a detonator junction,
illustrating a chamber and mating interface for a clip;
[0040] FIG. 3b is a cross-sectional view of a body for a detonator
junction taken across line 3b,3c-3b,3c of FIG. 3a;
[0041] FIG. 3c is a cross-sectional view of a body for a detonator
junction taken across line 3b,3c-3b,3c of FIG. 3a, including with a
cross-sectional view of a clip and a perspective view of a
detonator disposed therein;
[0042] FIG. 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;
[0043] FIG. 5 is a plan view of a blasting network using detonator
junctions and transmission lines; and
[0044] FIG. 6 is a plan view of an alternative blasting network
using detonator junctions and transmission lines.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0045] The preferred embodiments of the invention are now described
with reference to FIGS. 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.
[0046] 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.
[0047] FIG. 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.
[0048] 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.
[0049] 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.
[0050] 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.
[0051] 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.
[0052] 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 transmission lines 26
could be positioned and still allow proper initiation of a thermal
shock wave within each of the lines 26.
[0053] 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.
[0054] 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 FIGS. 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.
[0055] 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.
[0056] 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.
[0057] Transmission lines 26 and junctions 12 may be assembled into
a complex network to form a specific blasting pattern (see, e.g.,
FIG. 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.
[0058] 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.
[0059] As shown in FIG. 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.
[0060] Referring once again to FIG. 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 FIGS. 2a-b.
[0061] 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 FIGS. 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.
[0062] FIG. 2a is a top plan view and FIG. 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.
[0063] 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.
[0064] FIGS. 3a-c provide further illustration of the interaction
between the clip 16 and the mating interface 54. Specifically, FIG.
3a is a bottom plan view of the body 18 that illustrates the mating
interface 54 and chamber 22. FIG. 3b is a cross-sectional view on
line 3b,3c-3b,3c of the mating interface 54 and body 18, while FIG.
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.
[0065] 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.
[0066] 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.
[0067] 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.
[0068] FIG. 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.
[0069] As illustrated in FIG. 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
transmission 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.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] FIG. 5 is a plan view of a blasting network 88 using
detonator junctions 12a-c and transmission 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.
[0074] As illustrated in FIG. 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.
[0075] 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.
[0076] The network 88 illustrated in FIG. 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.
[0077] 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.
[0078] 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.
[0079] 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.
[0080] The blasting network 88 of FIG. 5 is one of many different
configurations which may be used with detonator junctions 12. In
FIG. 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 FIG. 5. The configuration of
detonator junctions 12a-c in FIG. 5 may be referred to as a
parallel blasting network 88.
[0081] Referring now to FIG. 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. FIG. 6 includes the same elements as in FIG. 5,
except that the network connection between detonator junctions 12
is different.
[0082] 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.
[0083] 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.
[0084] 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.
* * * * *