US2741179A - Electric detonators and electric blasting assemblies - Google Patents

Electric detonators and electric blasting assemblies Download PDF

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Publication number
US2741179A
US2741179A US209532A US20953251A US2741179A US 2741179 A US2741179 A US 2741179A US 209532 A US209532 A US 209532A US 20953251 A US20953251 A US 20953251A US 2741179 A US2741179 A US 2741179A
Authority
US
United States
Prior art keywords
electric
detonators
detonator
sheath
casing
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
US209532A
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English (en)
Inventor
Taylor Wilfrid
Forsyth William
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.)
Imperial Chemical Industries Ltd
Original Assignee
Imperial Chemical Industries Ltd
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
Application filed by Imperial Chemical Industries Ltd filed Critical Imperial Chemical Industries Ltd
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Publication of US2741179A publication Critical patent/US2741179A/en
Anticipated expiration legal-status Critical
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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
    • F42B3/18—Safety initiators resistant to premature firing by static electricity or stray currents

Definitions

  • the present invention relates to improvements in electric detonators of the kind embodying a device for minimising the possibility of the fusehead being accidentally fired by an electrostatic charge or high potential accumulated or induced on the leading wires.
  • the invention also relates to electric blasting assemblies embodying the improved electric detonators.
  • an electric detonator has its metal casing connected by an electrical conductor to one pole piece and the entire outer surface of said casing provided with a sheath of insulating material.
  • the said sheath of insulating material is for instance of a rubbery composition and preferably in the form of an adherent coating of a rubbery material.
  • the electrical conductor is preferably a metal strip or a metal wire.
  • the insulated lead ing wire associated with that side of the pole pieces carrying the said conductor may or may not constitute the leading Wire so associated in the next detonator in the series, and it is necessary that the cables and leading wires outside of the detonator are insulatedthroughout from the earth.
  • FIG. 1 represents a metal casing of each el'ec-. tric detonator and 2 the longitudinally bored plug of rubberlike material around which the detonator casing is tightly crimped at its upper end, in a series of over-i. folded indentations which have the effect of reducing the apparent diameter at this end.
  • 3 and 4 are respectively the secondary and primary initiating charges of the detonators and 5 are the matchheads of the electric fuseheads whereof 6 represents metallic pole pieces and 7 insulating layer separating the metallic pole pieces from one another.
  • the metal detonator casing 1 is brought by means of the good electrical connection 10 to the same potential as the right hand pole piece 6 of each of the electric detonators, but, owing to the coating 13 of rubberlike material over the surface of each detonator tube exposed to the exterior, there is no short circuit to earth through the detonator casing.
  • An improved blasting assembly comprising a pluility of electric detonators, there being in each of said etonators insulated leading wires, a metal casing conected by an electric conductor to one pole piece of a latch-head firing circuit whereby stray static electrical barges are caused to pass harmlessly to the said metal asing, a sheath of insulating material completely sur )unding said casing, said sheath causing the said static lectrical charges to be retained on said metal casing so lat the whole detonator system is at the same potenal until the said static electrical charges are greater ian the breakdown potential of the said sheath in which ase breakdown occurs and the said charges are disharged to earth, and wherein each of said electric detnators is connected in series with a source of electric urrent wherein the cables and leading wires outside the etonators are insulated from the earth.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Elimination Of Static Electricity (AREA)
  • Air Bags (AREA)
  • Coupling Device And Connection With Printed Circuit (AREA)
US209532A 1950-03-14 1951-02-06 Electric detonators and electric blasting assemblies Expired - Lifetime US2741179A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB290587X 1950-03-14

Publications (1)

Publication Number Publication Date
US2741179A true US2741179A (en) 1956-04-10

Family

ID=10285533

Family Applications (1)

Application Number Title Priority Date Filing Date
US209532A Expired - Lifetime US2741179A (en) 1950-03-14 1951-02-06 Electric detonators and electric blasting assemblies

Country Status (7)

Country Link
US (1) US2741179A (is")
BE (1) BE501819A (is")
CH (1) CH290587A (is")
DE (1) DE860324C (is")
FR (1) FR1033065A (is")
GB (1) GB681481A (is")
NL (2) NL159393B (is")

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2965033A (en) * 1956-10-19 1960-12-20 Hercules Powder Co Ltd Blasting cap assembly
US2974590A (en) * 1957-10-02 1961-03-14 Hercules Powder Co Ltd Static resistant electric initiator
US3100447A (en) * 1960-08-31 1963-08-13 Robert E Betts Igniter squib
US3128703A (en) * 1961-05-23 1964-04-14 Du Pont Water impervious detonator
US4271453A (en) * 1978-07-01 1981-06-02 Nissan Motor Company, Limited Igniter with coupling structure
US4380958A (en) * 1980-12-17 1983-04-26 The United States Of America As Represented By The Secretary Of The Army Electrostatic safe electric match
US4782911A (en) * 1981-06-01 1988-11-08 Imperial Chemical Industries Plc Seismic recording
US7124688B2 (en) * 2000-12-08 2006-10-24 Special Devices, Inc. Overmolded body for pyrotechnic initiator and method of molding same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2802421A (en) * 1953-11-09 1957-08-13 Hercules Powder Co Ltd Static resistant electric initiator

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1306510A (en) * 1919-06-10 Detonator
GB310364A (is") * 1928-04-24 1930-04-22 Wilhelm Eschbach
US2086533A (en) * 1935-10-30 1937-07-13 Du Pont Ignition composition

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1306510A (en) * 1919-06-10 Detonator
GB310364A (is") * 1928-04-24 1930-04-22 Wilhelm Eschbach
US2086533A (en) * 1935-10-30 1937-07-13 Du Pont Ignition composition

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2965033A (en) * 1956-10-19 1960-12-20 Hercules Powder Co Ltd Blasting cap assembly
US2974590A (en) * 1957-10-02 1961-03-14 Hercules Powder Co Ltd Static resistant electric initiator
US3100447A (en) * 1960-08-31 1963-08-13 Robert E Betts Igniter squib
US3128703A (en) * 1961-05-23 1964-04-14 Du Pont Water impervious detonator
US4271453A (en) * 1978-07-01 1981-06-02 Nissan Motor Company, Limited Igniter with coupling structure
US4380958A (en) * 1980-12-17 1983-04-26 The United States Of America As Represented By The Secretary Of The Army Electrostatic safe electric match
US4782911A (en) * 1981-06-01 1988-11-08 Imperial Chemical Industries Plc Seismic recording
US7124688B2 (en) * 2000-12-08 2006-10-24 Special Devices, Inc. Overmolded body for pyrotechnic initiator and method of molding same

Also Published As

Publication number Publication date
NL80499C (is")
NL159393B (nl)
GB681481A (en) 1952-10-22
DE860324C (de) 1952-12-18
FR1033065A (fr) 1953-07-08
BE501819A (is")
CH290587A (de) 1953-05-15

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