US2212118A - Electric blasting initiator - Google Patents

Electric blasting initiator Download PDF

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Publication number
US2212118A
US2212118A US268892A US26889239A US2212118A US 2212118 A US2212118 A US 2212118A US 268892 A US268892 A US 268892A US 26889239 A US26889239 A US 26889239A US 2212118 A US2212118 A US 2212118A
Authority
US
United States
Prior art keywords
plug
shell
initiator
electric blasting
leg wires
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US268892A
Other languages
English (en)
Inventor
Stanley L Handforth
Charles R Johnson
Gilbert H Smith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE461533D priority Critical patent/BE461533A/xx
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to US268892A priority patent/US2212118A/en
Application granted granted Critical
Publication of US2212118A publication Critical patent/US2212118A/en
Priority to FR920802D priority patent/FR920802A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B3/00—Blasting cartridges, i.e. case and explosive
    • F42B3/10—Initiators therefor
    • F42B3/103—Mounting initiator heads in initiators; Sealing-plugs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B3/00—Blasting cartridges, i.e. case and explosive
    • F42B3/10—Initiators therefor
    • F42B3/103—Mounting initiator heads in initiators; Sealing-plugs
    • F42B3/107—Sealing-plugs characterised by the material used

Definitions

  • the present invention relates'to -a new and improved electric blasting initiator.
  • the electric blasting initiators in use heretofore have contained a hard plug of sulfurous material for the purpose of holding the leg wires in place.
  • This wire-containing plug is surmounted in the charged initiator shell by a superimposed layer of viscous water-proofing material. On top of this waterproofing layer. is a final seal of sulfurous material.
  • the assembly described has many -defects and disadvantages. Such an assembly requires a shell of great length. When delay trains are employed the length of theshell is sometimes longer than the conventional copper alloys can be drawnwith convenience.
  • the object of the present invention electric blasting initiator of simplified design having improved resistance to water and moisture.
  • a further object is a method of manufacturing said initiators which eliminates the hazardous step of pouring molten materials into the charged shell.
  • An additional object is an electric blasting initiator adapted to mechanical assembly. Another object is such an initiator which is shorter in length.
  • the resilient plug is preferably of rubber comtion.
  • the strength of the plug determined by pulling one wire out of the assembled cap, was 7.8 pounds, and the results of a '70 pound ice water test for 24 hours were good.
  • the plug may be of any convenient shape and size so long as it is formed in place about the leg wires.
  • the electric blasting cap assembly according to our invention may be more readily understood by referring to the various figures of the drawing. These are for the purpose of illustration only and the scope of our invention is not to be limited thereby. Like numerals designate corresponding parts throughout the various figures.
  • Figure 1 is a view in cross-section of the improved electric blasting initiator of our inven- Figure 2 is an enlarged view of the resilient plug formed about the leg wires.
  • Figure 4 is an end view of the two portions of the mold.
  • the numeral l designates a metal shell into which the resilient plug 2 formed about leg wires 3, is crimped with uniform beads at 4 to form a moisture-proof, water-resistant closure.
  • the insulation 5 on the leg wires preferably terminates within the body of the plug as shown at 6 in Figure 2.
  • the conductors in the bridge plug type of cap terminate in the bridge posts I supporting the bridge wire 8.
  • the charged portion 9' loaded in conventional fashion with any convenient number of charges.
  • One method of forming the plugs about the wires is to place plug material about, the leg wires in the lower portion IU of the mold shown in Figure 3.
  • the leg wires are threaded through the entries H and passed on through the mold cavity 82, the'ends of the wires being held in place by the centering guides l3.
  • the top portion of the mold Ill-a. having complementary depressions is brought down and the plug mate-I rial is molded about the wires to form a cylindrical plug.
  • the relation between these two portions of the mold is shown in Figure 4, which is an end view thereof, including the guide posts I! for properly aligning the two sections.
  • the numeral 55 designates the heating fluid supply entry for heating the mold, while I6 is the exit for the same.
  • FIG. 3 is a Plugs testing at 30 were satisfactory.
  • Example A rubber composition was formulated as follows:
  • the resulting composition was formed into strips.
  • the leg wires for the electric blasting initiators were then passed in pairs through the cavities in the bottom portion of the mold as described in the foregoing. The end of each leg wire was stripped so that the insulation terminated somewhere Within the mold cavity through which the wire was threaded.
  • a strip of the uncured rub-- ber prepared according to the above formula was placed across the various mold cavities beneath the leg wires. Another strip was placed above said leg wires.
  • the mold was then -closed by putting it in a press and compressing the two portions together. The mold was then maintained at a temperature of approximately 305 F. for a period of approximately two minutes, at the end of which time the rubber plugs cured in place about said leg wires, were removed and inspected for defects.
  • the plugs were then crimped into place in charged initiator shells. They were then tested for water resistance and ability to withstand a pull on the leg wires.
  • the pull test was conducted by subjecting each of the leg wires to a 17 pound pull on a Scott tension tester of the pendulum type.
  • the pull test results are of course dependent upon many factors such as the type of rubber stock, the molding conditions of pressure and temperature, and the dimensions of the plug and the length of strip wire within the plug. The foregoing conditions werehighly satisfactory in that all plugs passed this particular test.
  • Our novel electric blasting initiator assembly displays manifold advantages. It ishighly su'-' perior to any assembly in the prior art with respect to resistance to water and moisture. It is much more durable than the hard plug initiators of the art, and also safer, due to the resilient closure member.v It is much shorter in length and requires a shorter metal shell. A very important advantage is that it may be made without any hazardous pouring of molten liquids into the charged shell. Furthermore, it is readily adapted to mechanical assembly.
  • An electric blasting initiator comprising a charged shell, spaced leg wires entering the mouth of said shell, a plug of rubber-like ma-- I terial of the character described formed about said spaced leg wires and disposed in a positionclosing the mouth of said shell, said leg wires extending through said plug material substantially in a straight line and substantially parallel to each other, and a crimp extending around the circumference of said shell in the region enclosing said plug forcing the shell wall into and deforming said rubber-like plug to. complete a water impervious juncture. q a
  • an electric blasting initiator of the type including a charged shell, spaced leg wires entering the mouth of said shell, a high resistance wire completing the circuit between said leg wires within said shell, and an explosive charge in firing relationship with said high resistance wire;
  • the closure element consisting of a plug of 35 rubber-like material of the" character described molded about and between said leg wires and disposed in a position closing the mouth of said shell, said leg wires extending through said plug material substantially in a straight line and substantially parallel to each other, and a crimp extending around the circumference of said shell in the region enclosing said plug forcing the shell wall into and deforming said rubber-like plug to complete a water impervious juncture.
  • An electric blasting initiator comprising. a charged shell, spaced leg wires entering the mouth of said shell, a plug of rubber composition of the character described molded about and between said spaced leg wires and disposed in a position closing the mouth of said shell, said rubber plug being characterized by a durometer hardness of at least 30, said leg wires extending through said plug substantially in a straight line and substantially parallel to each other, the insulation on said leg wires terminating within the body of said plug, and a crimpextending around the circumference-of .said shell in the region enclosing said plug forcing the shell wall into and deforming said rubber-like plug to complete a water impervious juncture.
  • An electric blasting initiator comprising-a charged shell, spaced leg wires entering. the mouth of said shell, a plug of rubber-likemateria'lof the character described formed about said spaced leg wires and disposed in-a position closing the mouth of said shell, and a crimp extending around the circumference of said shell in the region enclosing said plug forcing the shell wall into and deforming said rubberlike plug to complete a water impervious juncture.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Connector Housings Or Holding Contact Members (AREA)
US268892A 1939-04-20 1939-04-20 Electric blasting initiator Expired - Lifetime US2212118A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE461533D BE461533A (enrdf_load_stackoverflow) 1939-04-20
US268892A US2212118A (en) 1939-04-20 1939-04-20 Electric blasting initiator
FR920802D FR920802A (fr) 1939-04-20 1945-11-14 Détonateur électrique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US268892A US2212118A (en) 1939-04-20 1939-04-20 Electric blasting initiator

Publications (1)

Publication Number Publication Date
US2212118A true US2212118A (en) 1940-08-20

Family

ID=23024957

Family Applications (1)

Application Number Title Priority Date Filing Date
US268892A Expired - Lifetime US2212118A (en) 1939-04-20 1939-04-20 Electric blasting initiator

Country Status (3)

Country Link
US (1) US2212118A (enrdf_load_stackoverflow)
BE (1) BE461533A (enrdf_load_stackoverflow)
FR (1) FR920802A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2457440A (en) * 1947-06-05 1948-12-28 Herbert L Booth Method for producing tufted plastic combs
US2477458A (en) * 1944-12-19 1949-07-26 Du Pont Electric blasting cap
US2606475A (en) * 1946-06-27 1952-08-12 Cardox Corp Electrically ignited match head and the method for making the same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2477458A (en) * 1944-12-19 1949-07-26 Du Pont Electric blasting cap
US2606475A (en) * 1946-06-27 1952-08-12 Cardox Corp Electrically ignited match head and the method for making the same
US2457440A (en) * 1947-06-05 1948-12-28 Herbert L Booth Method for producing tufted plastic combs

Also Published As

Publication number Publication date
FR920802A (fr) 1947-04-18
BE461533A (enrdf_load_stackoverflow)

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