WO1996011375A1

WO1996011375A1 - Method and apparatus for transmission of a detonator initiation to a detonating cord

Info

Publication number: WO1996011375A1
Application number: PCT/US1995/013561
Authority: WO
Inventors: John E. Capers, Iii
Original assignee: Austin Powder Company
Priority date: 1994-10-07
Filing date: 1995-10-10
Publication date: 1996-04-18
Also published as: PE46296A1; AU4132696A

Abstract

A connector block for retaining a detonator and transmission tubes in close proximity is disclosed. The block is preferably formed of copolymer polypropylene and comprises a housing and a retention member extending from the housing. The housing has a channel with detonator retaining means positioned therein and a closed end having a convex outer surface. The retention member includes a concave retainer wall spaced from and opposing the closed end of the housing to create a gap therebetween, and a connection member that connects the retainer wall to the housing. The connector block can comprise part of a system, wherein the system further comprises a detonator having a delay tube and an explosive end. The detonator is retained within the channel with the explosive end positioned next to the closed end of the housing. Transmission tubes are retained within the gap. When the detonator explodes, the force of the explosion is directed through the aperture to initiate the transmission tubes. The connector block retains its dimensional stability during the explosion thereby insuring that the force is absorbed by the transmission tubes.

Description

METHOD AND APPARATATUS FOR TRANSMISSION OF A DETONATOR INITIATION

TO A DETONATING CORD

Field of the Invention The present invention relates to a system and apparatus used to initiate blasting signal transmission devices, wherein the system comprises a connector block and a detonator, and the apparatus comprises a connector block. More particularly, the present invention relates to a low-energy detonator having an explosive end, the detonator directing its explosive force towards the explosive end and a connector block which contains and directs the explosive force of the detonator in order to: 1) insure efficient initiation of one or more transmission tubes, and 2) reduce flying shrapnel. Background of the Invention

When detonating a plurality of blasting charges it is frequently desirable to control the timing of the detonations. This can be accomplished by deploying transmission tubes from a central initiating point. The central initiating point is often a connector block which holds one or more transmission tubes or detonating cords in proximity with a detonator. When the detonator explodes it initiates the transmission tubes or detonating cords which then detonate respective detonators. The term transmission tubes, as used herein, refers to signal transmission tubes or transmission lines used to initiate detonators. Transmission tubes are generally comprised of a flexible hollow tube having reactive substances coated on the interior surface thereof while still leaving a hollow in the center of the tube. A transmission tube of this type can carry a signal to detonate individual detonators whereby the signal does not destroy the tube. The term signal, as used herein, refers to both a detonating Shockwave or deflagrating flame which is transmitted along the reactive substances coated on the interior of the tube. The term detonating cord refers to a signal transmission device having a core of pyrotechnic material. A typical detonating cord has a pyrotechnic core, preferably pentaerythritol tetranitrate (PETN) surrounding a cotton thread. A plastic tape, usually consisting of polyethylene, surrounds the core, and plastic yarns, usually consisting of polypropylene, wrap and surround the plastic tape. An extruded outer jacket, usually consisting of polyethylene, covers the plastic yarns. For the purpose of brevity, when the term transmission tube(s) is used herein, it will be understood that detonating cord could alternatively be used, the scope of the invention thus covering transmission tubes, detonating cords and any equivalent structure for transmitting a signal.

The term detonator generally refers to any explosive device which can be used to initiate transmission tubes. More particularly, the term detonator as used herein refers to non-electric detonators which generally consist of an elongated tubular shell containing a succession of charges linearly arranged within the shell. Detonators of this type are usually activated by initiating a transmission tube which then transmits a signal, as described above, to the detonator. The incoming signal ignites a charge within the detonator, the charges within the detonator then progressively initiating in a linear fashion until the main charge, commonly referred to as a base charge or primary charge, is ignited. When the primary charge explodes, the end of the shell containing the primary charge ruptures and transmits the explosive force to transmission tubes held in close proximity to the detonator. Typical non-electric detonators and assemblies using these detonators are shown in U.S. Letters Patent No. 4,426,993 to Yunan, U.S. Letters Patent No. 4,495,867 to Mitchell, Jr. et al., U.S. Letters Patent No. 4,539,909 to Day et al., U.S. Letters Patent No. 4,335,652 to Bryan, U.S. Letters Patent No. 4,424,747 to Yunan, U.S. Letters Patent No. 4,248,152 to Yunan and U.S. Letters Patent No. 4,429,632 to Yunan. Connector blocks used to hold transmission tubes in close proximity with detonators typically consist of a plastic block, comprised of polyethylene, having one section which holds a detonator and a second section which holds transmission tubes in proximity to the explosive end of the detonator. Some examples of typical connector blocks are discussed in the following U.S. patents.

U.S. Letters Patent No. 4,722,279 to Yunan discloses a non-electric detonator device having a holder for holding a low-energy detonating cord in abutting relationship to a rupturable membrane. The membrane seals the top end of a tubular shell which contains an explosive charge at the bottom. When the detonating cord is detonated it ruptures the membrane and initiates the charge in the bottom of the shell. The charge then initiates lines held in proximity to the charge.

U.S. Letters Patent No. 4,248,152 to Yunan discloses an explosive booster having two coaxial shells connected to a donor detonating cord. The booster is positioned in a connector having two open ends. A receiver detonating cord or trun line is held next to the explosive end of the booster by a slotted, hinged locking means which forms a closure over a slot into which the receiver cord is placed. U.S. Letters Patent No. 5,012,741 to Peebles et al. discloses a transmission tube initiator having a holder attached to a body, the holder having two diametrically-opposed grooves. Transmission tubes are wrapped around the holder and contained in the grooves. A sleeve is placed over the holder and is threadingly received on the body of the initiator. A charge contained in the body is fired thereby initiating the transmission tubes. U.S. Letters Patent No. 5,171,935 to

Michna et al. discloses a low-energy blasting initiation system method and surface connection thereof. The connector consists of an integrally formed plastic member having a housing with a channel passing completely therethrough, the housing receiving a detonator. Retention means on the housing hold one or more transmission tubes in juxtaposed relationship with the explosive end of the detonator. The retention means is connected to the housing by a resiliently deformable segment, the segment being of reduced size and material thickness as compared to the housing.

One of the problems with the prior art heretofore mentioned is relatively poor efficiency in initiating transmission tubes. When detonators initiate, the portion of the detonator containing the base charge ruptures. The explosive force is thereby released across this entire portion, which can be one-quarter to one-third the length of the detonator. The explosive force is not focused or directed towards the end of the detonator, which is where the transmission tubes are positioned. This problem is exacerbated by the connector blocks, which do not contain and direct the explosive force towards the transmission tubes, but instead allow it to dissipate. Additionally, the part of the connector block used to retain the transfer tubes or detonating cord is displaced by the force of the explosion thus further dissipating the force of the explosion. Another problem with existing connector blocks is, that by not containing the explosion of the detonator, they allow shrapnel to be projected outward from the center of the explosion. This creates a potential safety hazard. Summary of the Invention In accordance with the present invention there is provided a connector block for firmly holding transmission tubes in close proximity to the explosive end of a detonator. The connector block directs the explosion towards the transmission tubes to provide efficient ignition. Furthermore, the connector block contains the explosion to reduce or eliminate flying shrapnel. The connector block generally includes a housing and a retention member. The housing has a channel formed therein and retention means for retaining a detonator. The housing has a closed end having an aperture formed therein, the aperture being in communication with the channel.

The retention member comprises a retainer wall and connecting means. The retainer wall is spaced from and opposes the closed end of the housing creating a gap therebetween. The connecting means connects the retainer wall to the housing, is generally rigid and is at least 70% as wide as the retainer wall. In accordance with another embodiment of the present invention, there is provided a connector block composed of copolymer polypropylene for firmly holding transmission tubes in close proximity to the explosive end of a detonator. The connector block directs the explosion towards the transmission tubes to provide efficient ignition. Furthermore, the connector block contains the explosion to reduce or eliminate flying shrapnel. The connector block generally includes a housing and a retention member. The housing has a channel formed therein and retention means for retaining a detonator. The housing has a closed end having an aperture formed therein, the aperture being in communication with the channel.

The retention member comprises a retainer wall and connecting means. The retainer wall is spaced from and opposes the closed end of the housing creating a gap therebetween. The connection means connects the retainer wall to the housing and is generally rigid.

In operation, a detonator is placed into the channel of the housing and retained therein by the retention means. The explosive end of the detonator is juxtaposed with the aperture.

Transmission tubes or detonator cord are placed in the gap formed between the retainer wall and the closed end of the housing. When the detonator explodes, the closed end of the housing confines the explosion. This prevents shrapnel from projecting outward and helps direct the force of the explosion through the aperture to the transmission tubes. The rigid connecting means holds the retainer member in position during the explosion so that the transmission tubes remain firmly pressed in the gap between the retainer wall and the closed end during the explosion. The force of the explosion, therefore, is not dissipated and the transmission tubes absorb a significant amount of the force of the explosion, which provides for efficient transmission tube initiation.

In accordance with another embodiment of the present invention a detonation initiation system is provided, the device comprising a connector block as described above used in combination with a directionally-explosive detonator. The detonator includes an outer shell having an explosive end, a primary charge within the explosive end and a delay charge within the outer shell juxtaposed with the primary charge. A delay tube, which is generally a cylindrical metal sleeve, surrounds at least part of the delay charge. The delay tube reinforces the portion of the shell in which it is retained. When the detonator is ignited the delay charge is first ignited and it ignites the primary charge which explodes, rupturing the shell. The portion of the shell reinforced by the delay tube, however, does not rupture. The force of the explosion is therefore directed towards the explosive end of the detonator and towards the transmission tubes to be initiated. It is an object of the present invention to provide a connector block which holds transmission tubes in close proximity to the explosive end of a detonator.

It is also an object of the present invention to provide a connector block which directs the force of the detonator explosion towards the transmission tubes retained by the connector block.

It is also an object of the present invention to provide a connector block which contains the explosion of the detonator thereby reducing or eliminating flying shrapnel.

It is also an object of the present invention to provide a connector block which holds the transmission tubes firmly in place during explosion of the detonator. Another object of the invention is to provide a connector block as described above having a housing and a retention member. The housing having an open channel, retaining means for retaining a detonator, a closed end and an aperture in the closed end which communicates with the channel. The retention member includes a retainer wall and connection means. The retainer wall is spaced apart from and opposes the closed end of the housing thus creating a gap therebetween. The connection means is generally rigid, at least 70% as wide as the retainer wall and connects the retainer wall to the housing.

Another object of the present invention is to provide a connector block as described above wherein the housing is an elongated member having a generally rectangular cross section.

Another object of the present invention is to provide a connector block as described above wherein the connection means is substantially as wide as the retaining wall.

Another object of the present invention is to provide a connector block as described above wherein the housing further comprises a channel wall extending from the closed end, the channel wall partially covering the channel. Another object of the present invention is to provide a connector block as described above wherein the block is formed of copolymer polypropylene. Another object of the present invention is to provide a connector block as described above wherein the closed end has a convex outer surface and the aperture is formed in the apex of the outer surface. Another object of the present invention is to provide a connector block as described above wherein the connecting means extends outward from the housing and forms an angle of greater than 90° with the housing. Another object of the present invention is to provide a connector block as described above wherein the connecting means forms an angle between 100°-170° with the housing.

Another object of the present invention is to provide a connector block as described above wherein the housing has a cross-sectional wall thickness, the connecting means having a thickness greater than the cross-sectional wall thickness of the housing. Another object of the present invention is to provide a connector block as described above wherein the aperture has an outside perimeter and the detonator has an outside perimeter, the outside perimeter of the aperture being one-half to three times as large as the outside perimeter of the outside perimeter of the detonator.

It is another object of the present invention to provide a connector block as described above used in combination with a directionally- explosive detonator. The detonator includes an outer shell into which a transmission tube can be inserted, the outer shell having an explosive end. A primary charge is positioned within the explosive end and a delay charge is positioned within the outer shell and juxtaposed with the primary charge. A delay tube surrounds at least some of the delay tube thereby reinforcing a portion of the outer shell.

Another object of the present invention is to provide a connector block and a detonation initiation device which are economical to manufacture and simple to use.

Additional objects, features and advantages will be apparent to those skilled in the art upon reading the description which follows and the appended claims. Brief Description of the Drawings

FIG. 1 is a top view of a connector block in accordance with the present invention.

FIG. 2 is a side view of the connector block shown in FIG. 1.

FIG. 3 is a sectional view of the connector block taken along lines 3-3 of FIG. 1.

FIG. 4 is a sectional view of the connector block taken along lines 4-4 of FIG. 1. FIG. 5 is a sectional view of the connector block taken along lines 5-5 of FIG. 1.

FIG. 6 is a side view of a detonator in accordance with the present invention.

FIG. 7 is a cross-sectional view of the detonator shown in FIG. 6.

FIG. 8 is an actual-size, side view of the detonator shown in FIGS. 6 and 7 having a seal and a transmission tube inserted therein and being crimped about its outer periphery. FIG. 9 is a sectional side view of the connector block shown in FIG. 1 with the detonator shown in FIG. 8 inserted into the connector block housing and transmission tubes retained in the gap between the closed end of the housing and the retainer wall. FIG. 10 is a view of the components shown in FIG. 9 after the detonator has exploded. Detailed Description of a Preferred Embodiment

Referring now to the drawings where the purpose is for describing a preferred embodiment of the present invention, and not for limiting same, FIG. 1 shows a connector block 10 in accordance with the present invention.

Connector block 10 is preferably made of an injection-molded copolymer polypropylene which had performed better in trials than other plastics, particularly polyethylenes. Copolymer polypropylene has the rigidity to maintain the integrity of retention member 62 whereby the retention member is not displaced during the explosion of a detonator, which is discussed further below. Additionally, the copolymer polypropylene does not shatter when the detonator explodes, even at temperatures as low as -40° F. This further augments the structural integrity of the connector block, which insures that the transmission tubes are maintained in close proximity to the explosive end of the detonator when the detonator is exploded.

Preferably, the copolymer polypropylene of which block 10 is composed is manufactured by HiMont, U.S.A. and has a general polymer number of 8523. This material has the following properties:

Units of

Propertv Measurement Value

Tensile Strength psi 3000 Yld

Flex Modulus psi 150,000

Elongation § Yld % 10

N Izod § RT 1/4 ft-lb/in 10

Rockwell Hardnss R65

Spec Grav/Dens gm/cc 0.901

DTUL @ 264 psi deg F 120

DTUL @ 56 psi deg F 167

U.L Rating HB

Thickness U.L. @ in 0.062

Melt Flow gm/lOmin 4

FDA Approved Y

FDA Approvals 21CFR177.1520(a) (3) (i) (c) As can be seen in FIGS. 1 and 2, connector block 10 generally comprises a housing 12 and a retention member 62. Housing 12 is an elongated member having a generally rectangular cross section, although housing 12 could optionally be cylindrical. Housing 12 has a first end 14, a second end 16 and four generally planar sides, 18, 20, 22 and 24, respectively. First end 14 is generally flat and is perpendicular to sides 18, 20, 22 and 24. First end 14 has an exterior wall 26 and an interior wall 28. Second end 16 is opposite end 14 and has a convex outer surface 30.

An elongated open channel 32 is centrally formed along side 18 of housing 12 and has two generally planar, opposing side walls 34 and a radiused base 36, best seen in FIG. 4. Channel 32 does not extend through second end 16, second end 16 therefore being referred to as "closed." Two retention tabs 38 are formed, respectively, on opposing side walls 34 near first end 14. A slot 40 is formed in side 22 of housing 12. Slot 40 is generally rectangular, communicates with channel 32 and is linearly aligned with, and is slightly wider than, tabs 38. An elongated opening 42 is centrally formed in end 14 wherein opening 42 has two planar, divergent sides 44 and a radiused base 46. A support rib 48 is formed centrally in base 36 of channel 32. Rib 48 extends linearly along base 36 from slot 40 to interior wall 28 of end 14. Rib 48 extends upwards from base 36 to the bottom of radiused base 46.

A channel wall 18A, best seen in FIG. 2, is formed near the second end 16 of housing 12 and has an inner edge 19 opposite second end 16. In the embodiment shown, convex surface 30 has an apex 31 and the distance between apex 31 and inner edge 19 is 9/16 inches as measured in a straight line bisecting wall 18A. Walls 18A, 20, 22 and 24 join to define a cavity 50. Cavity 50 communicates with channel 32, as is best seen in FIG. 3. Wall 18A has a planar outside surface 52 which is generally flush with side 18 of housing 12 and is integrally formed with second end 16. Wall 18A has a radiused inner surface 54, best seen in Fig. 5, which opposes a radiused inner surface 56 of wall 22. Surfaces 54 and 56 become increasingly closer to one another as they near second end 16. Cavity 50 therefore becomes gradually narrower as it nears second end 16. This allows for efficient alignment of the charge end of a detonator. An insert 58, best seen in Fig. 2, is integrally formed in channel 32 relative second end 16 and extends to cavity 50. Insert 58 is formed along walls 34 and base 36 of channel 32 and narrows channel 32; channel 32 becoming progressively more narrow as it nears cavity 50. An aperture 60 is formed in second end 16 of housing 12 and communicates with cavity 50. Aperture 60 is generally rectangular, it being understood that aperture 60 could be of any shape, and is positioned on convex surface 30 between walls 18A, 20, 22 and 24. In the embodiment shown, aperture 60 is formed at the apex 31 of convex surface 30.

A retention member 62 is integrally formed with housing 12 and is comprised of a connector wall 64 and a retainer wall 66. Connector wall 64 is generally rigid and extends outward at an angle greater than 90° from wall 20. In the embodiment shown, the angle between wall 20 and connector wall 64 is 135°. Connector wall 64 has a width equal to the width of wall 20, it being understood that the width of wall 64 only need be enough to maintain the rigidity of connector wall 64 during operation of block 10.

Retainer wall 66 is generally rigid and integrally formed with connector wall 64. Retainer wall 66 is radiused, generally U-shaped, and has a radiused outer end 68. In the embodiment shown, retainer wall 66 has a width equal to the width of second end 16 (20 millimeters in the embodiment shown) so that it completely covers end 16, it being understood that retainer wall 66 need only be of a sufficient width to retain transmission tubes and to adequately contain the force of the explosion of a detonator so as to efficiently initiate the transmission tubes. Furthermore, in the embodiment shown, the width of connector wall 64 is equal to the width of retainer wall 66, it being understood that the width of connector wall 64, in relation to the width of retainer wall 66, need only be great enough to insure the proper functioning of block 10. A width for connector wall 64 of 70% or more of the width of retainer wall 66 will give adequate rigidity to retention member 62, as will be explained more fully below. Connector wall 64 and retainer wall 66 have the same uniform thickness, this thickness being greater than the cross- sectional thickness of the respective sides 18, 20, 22 and 24 of housing 12.

A retention gap 70 is formed between retainer wall 66 and convex outer surface 22 of second end 16. Transmission tubes are retained in gap 70, as is explained in more detail below. A planar, angular surface 72 is formed on wall 24 relative second end 16. A mouth 74, best seen in Figs. 2 and 9, is formed between surface 72 and radiused outer end 68. Mouth 74 is wider than gap 70 so that transmission tubes may be inserted into gap 70 via mouth 74 with relative ease.

Turning now to FIGS. 6, 7, and 8, a detonator 100 is shown. Detonator 100 is generally an elongated cylinder formed about a central axis A. Detonator 100 has a hollow outer shell 102 which, in the preferred embodiment, is made of aluminum, although it can be made from any other suitable material such as steel or brass. Outer shell 102 has a first section 102A and a second section 102B integrally formed with one another. Section 102B has a thinner cross section and a smaller outer diameter than section 102A.

Detonator 100 has a first end 104 and a second end 106. End 104 is open and can receive a transmission tube, as is discussed below. Second end 106 is closed and has a cylindrical aperture 108 formed in its center.

Turning now to FIG. 7, the internal components of detonator 100 are shown. Moving from right to left on the drawing, an elongated cavity 110 is formed within first section 102A. A cup 112, which is a generally cylindrical metal sleeve, preferably formed of aluminum or brass, and having a planar base, is contained within first section 102 next to cavity 110. A cylindrical aperture 114 is centrally formed in the base of cup 112.

A transition charge 116 is located next to cup 112, aperture 114 communicating with charge 116. Transition charge 116 is preferably composed of zirconium powder (24%) and red lead (74%) , with Viton B fluoridized synthetic rubber (2%) used as a binder. This is a typical pyrotechnical composition which is relatively insensitive to impact by percussion and friction. Although a transition charge as described can be used in the embodiment disclosed to insure transmission of the signal from the transmission tube, the use of a transition charge is optional.

A delay composition 118 abuts the transition charge. The delay composition 118 comprising a standard pyrotechnic material which is a mixture of red lead (60%) and silicon (40%) .

A delay tube 120 is a cylindrical metal sleeve, preferably formed of steel, which surrounds the transition charge 116 and the delay composition 118. Delay tube 120 reinforces the portion of section 102B of shell 102 in which it is retained. A primary charge 122 is contained within section 102B at second end 106. Primary charge 122 abuts delay composition 118 and delay tube 120. Primary charge 122 is a standard pyrotechnic mixture of dextronated lead azide, preferably weighing 210 milligrams.

Turning now to FIG. 8, detonator 100 is shown after a sealing collar 150 and transmission tube 200 have been inserted in end 104 and shell 102 has been crimped.

A sealing collar 150, which is preferably made of rubber, is positioned in end 104. Collar 150 has an annular gasket 152 having an annular outer surface 154. A sleeve (not shown) is integrally formed with gasket 152 and extends along axis A from the surface of gasket 152 opposite outer surface 154. Gasket 152 has an outside diameter approximately equal to the outside diameter of first section 102A. The sleeve has an outer diameter which is slightly less than the inside diameter of section 102A of outer shell 102 so that the sleeve may be inserted into end 104. A cylindrical cavity (not shown) is formed through collar 150. A transmission tube 200 extends through the cavity in collar 150 and is retained in elongated cavity 110 with an end of tube 200 resting against the base of cup 112.

A series of crimps or indentations 124 extend about the outer periphery of section 102A of outer shell 102. The indentations 124 press shell 102 against the sleeve of collar 150 and against transmission tube 200 thereby preventing transmission tube 200 and collar 150 from being removed from detonator 100. Turning now to FIG. 9, a cross sectional view of a connector block 10 is shown having a detonator 100 contained within housing 12 and transmission tube(s) 300, which are to be initiated by detonator 100, retained by retention member 62. Detonator 100 is placed within housing 12 by inserting the second end 106 into cavity 50 and then pressing detonator 100 into channel 32 until it seats against support rib 48. In this position, detonator 100 is retained by retention tabs 38 and end 106 is juxtaposed and aligned with aperture 60. Transmission tube 200 extends outward from housing 12 through opening 42.

Transmission tube(s) 300 are retained within gap 70 by simply pressing them into gap 70 through mouth 74. To initiate the transmission tube(s) 300 a signal is passed through transmission tube 200 to detonator 100. The signal ignites transition charge 116 which ignites delay composition 118 which ignites primary charge 122. When primary charge 122 detonates the force of the explosion ruptures the portion of section 102B of shell 102 not reinforced by delay tube 120 while the portion of section 102B reinforced by delay tube 120 does not rupture. The force of the explosion is therefore directed towards end 106 by delay tube 120.

As mentioned above, end 106 is contained within cavity 50 and juxtaposed and aligned with aperture 60. Walls 18A, 20, 22 and 24 and end 16 therefore contain the force of the explosion and direct it through aperture 60 to transmission tubes 300. Retainer member 62, comprising connector wall 64 and retainer wall 66, is rigid because of its structure and because of the copolymer polypropylene from which it is made, and essentially does not move, relative to housing 12, during the explosion. Furthermore, because block 10 is made from copolymer polypropylene, retainer member 62 does not shatter or crack during the explosion. Transmission tubes 300 are therefore maintained under pressure and in close proximity to end 16 and aperture 60 which insures that they absorb the full force of the explosion. The design of connector block 10 thereby insures efficient initiation of transmission tubes 300. Initiation is even more efficient when block 10 is used in combination with detonator 100 because the explosion is directed towards end 106 by delay tube 120, as explained above.

Finally, closed end 16, walls 18A, 20, 22 and 24 contain most of the explosion and reduce flying shrapnel thus making block 10 relatively safe to use. Producing block 10 from copolymer polypropylene, which does not shatter or crack and hence does not project plastic fragments, enhances the safety performance of block 10. While the invention has been shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit thereof.

Claims

What is claimed is:

1. A connector block for retaining transmission tubes in close proximity with a detonator, said connector block comprising: (a) a housing including: a channel formed therein, and a closed end having a convex outer surface, and (b) a retention member extending from said housing, said retention member including: a retainer wall having a concave surface spaced from and opposing said convex outer surface and forming a gap therebetween, said gap for receiving transmission tubes, and a connector for connecting said retainer wall to said housing;

whereby said transmission tubes are retained in said gap and a detonator is placed within said channel and when said detonator is detonated, the explosion is directed through said closed end to said transmission tubes.

2. A connector block as described in claim 1 wherein said closed end has a width and said retainer wall has a width substantially equal to the width of said closed end.

3. A connector block as described in claim 1 wherein said housing is elongated and has a generally rectangular cross section, said housing thereby having four sides wherein each side has a width.

4. A connector block as described in claim 3 wherein said connection means extends substantially across the entire width of one of said four sides of said housing.

5. A connector block as described in claim 1 further comprising a channel wall extending from said closed end of said housing, said channel wall partially covering said channel whereby upon detonation of said detonator, said channel wall prevents shrapnel from being projected outward through said channel.

6. A connector block as described in claim 5 wherein said closed end has an outer surface and said channel wall has an inner edge opposite said outer surface, the distance between said outer surface and said inner edge being at least 9/16 inches as measured along a straight line bisecting said channel wall.

7. A connector block as described in claim 1 wherein said block is formed of a copolymer polypropylene.

8. A connector block as described in claim 1 wherein said closed end of said housing has a convex outer surface, said outer surface having an apex, and an aperture being formed at said apex of said outer surface whereby said aperture is in close proximity to the transmission tubes and the force of the explosion of said detonator is directed through said aperture to initiate the transmission tubes.

9. A connector block as described in claim 1 wherein said connecting means extends outward from said housing and forms an angle of greater than 90° with said housing.

10. A connector block as described in claim 1 wherein said angle is 100°-170°.

11. A connector block as described in claim 1 wherein said housing has a cross-sectional wall thickness, said connecting means having a thickness greater than the cross-sectional wall thickness of said connector block.

12. A connector block for retaining transmission tubes in close proximity with a detonator, said connector block being formed from copolymer polypropylene, said connector block comprising:

(a) a housing having ends and a channel formed therein, and

(b) a retention member extending from said housing, said retention member having: a retainer wall spaced from one of said ends of said housing and forming a gap therebetween, said gap for receiving transmission tubes, a connector means for connecting said retainer wall to said housing,

whereby said transmission tubes are retained in said gap and a detonator is placed within said channel and when said detonator is detonated said connector block retains its dimensional integrity and the explosion initiates the transmission tubes.

13. A connector block as described in claim 12 wherein said connection means has a width equal to 70% or more of the width of said retainer wall.

14. A connector block as described in claim 12 wherein said housing has a closed end and said connector block further comprises a channel wall extending from said closed end of said housing, said channel wall partially covering said channel, said closed end having an outer surface and said channel wall having an inner edge opposite said outer surface, the distance between said outer surface and said inner edge being at least 9/16 inches as measured along a straight line bisecting said channel wall.