The Ensign-bickford Company

Ensign-bickford Aerospace & Defense Company

Brendan M Walsh

Paul Neil Marshall

Thomas C Tseka

David W Ewick

James E Fritz

Kenneth A Rode

P Cary Franklin

This invention relates to a detonating cord () having a core () of reactive material and a composite jacket around the core, and the method of its manufacture. The composite jacket includes an interior jacket () in contact with the core and a sacrificial jacket () disposed over the interior jacket. The sacrificial jacket prevents the cord from being cut off by the detonation of another detonating cord of like core load disposed adjacent thereto. The sacrificial jacket is separable from the interior jacket beneath it under the force of the adjacent detonating cord, thus absorbing energy and allowing the first detonating cord to remain intact. The detonating cord may have a core load of not more than 3.2 grams/meter (15 grains/ft) or, optionally, less than 1.25 g/m (6 grains/ft). The interior jacket may be free of metal jacket layers. Optionally, the outer cross-sectional diameter of the cord may be not more than about 3.8 mm (0.15 inch) so that it can be inserted into a standard detonator. The sacrificial jacket may be made from polyethylene and may have a thickness of about 0.25 mm (0.01 inch).

Detonating cord with protective jacket

An initiator ( ) assembled from a housing ( ), an output charge ( ) and an initiation means ( ) includes a pulverulent ignition charge ( ) disposed in direct initiation relation to the initiation means, and an output charge ( ) that may contain a pulverulent deflagration-to-detonation transition (DDT) charge ( ) and an explosive base charge ( ). The ignition charge ( ) has an average particle size of less than 10 microns, or even less than 5 microns, e.g., 1 to 2 microns. The initiation means may include a semiconductor bridge ( ) and the ignition charge ( ) may be compacted with a force of less than about 5880 psi, e.g., with a force of 1000 psi. In another embodiment, an initiator ( ) includes a low-energy electrical initiator ( ), a loosely packed BNCP ignition charge ( ) and a pyrotechnical output charge ( ).

Initiator with loosely packed ignition charge and method of assembly

A shock-resistant electronic circuit assembly (,) is provided in which an electronic circuit is encased in an encapsulation (,) that engages a surrounding enclosure (,) in shock-dispersing contact therewith. The encapsulation may have a plurality of edges (,), fins (,) or bosses (,) that bear against the enclosure. The encapsulation may include a shock-absorbing material (,) disposed against the enclosure to protect the circuit against vibrations and a structural support material such as a casing (,) to protect the circuit against stress. The circuit assembly (,) may be part of a sheathed initiator assembly (,) that includes a transfer member (,) for converting shock wave energy into electrical energy for the electronic circuit, and the released energy may be converted into a detonation initiation signal. Assembly (,) may be part of a detonator (,) that receives a non-electric initiation signal and detonates following the delay determined by the electronic circuit. The detonator housing (,) or an optional sleeve (,) provides an enclosure for the assembly (,). The circuit encapsulation may include one or more bushings such as O-rings (,&prime;) disposed about the circuit casing (,).

Shock-resistant electronic circuit assembly

A shock-resistant electronic circuit assembly (10) is provided in which an electronic circuit is encased in an encapsulation (14) that engages a surrounding enclosure (18, 22) in shock-dispersing contact therewith. The encapsulation may have a plurality of edges (16, 16a, 16b), fins (24) or bosses (70) that bear against the enclosure. The encapsulation may include a shock-absorbing material (14f) disposed against the enclosure to protect the circuit against vibrations and a structural support material (14e) to protect the circuit against stress. The circuit assembly (10) may contain a capacitor (34) for storing an electrical signal and timing circuitry for releasing the stored energy after a predetermined delay. The circuit assembly (10) may be part of a transducer-circuit assembly (55) that includes a transducer module (58) for converting shock wave energy into electrical energy for the electronic circuit, and the released energy may be converted into a detonation initiation signal. Assembly (55) may be part of a detonator (100) that receives a non-electric initiation signal and detonates following the delay determined by the electronic circuit. The detonator housing (112) or an optional sleeve (22) provides an enclosure for the assembly (55).

An electronic delay circuit (10) for use in a detonator (100) has a switching circuit (20) and a timer circuit (22). Switching circuit (20) controls the flow of a stored charge of electrical energy from a storage capacitor (12) to a bridge initiation element such as a semiconductor bridge (18) or a tungsten bridge. The timing of the release of this energy is controlled by timer circuit (22). Switching circuit (20) is an integrated, dielectrically isolated, bipolar CMOS (DI BiCMOS) circuit, whereas timer circuit (22) is a conventional CMOS circuit. The use of a DI BiCMOS switching circuit allows for greater efficiency of energy transfer from the storage capacitor (12) to the semiconductor bridge (18) than has previously been attained.

Hybrid electronic detonator delay circuit assembly

A detonator (100) assembled from a housing (112), an output charge (144) and an initiation means (110, 120, 58, 54) includes a pulverulent ignition charge (46a) disposed in direct initiation relation to the initiation means, and an output charge (144) that may contain a pulverulent deflagration-to-detonation transition (DDT) charge (144a) and a base charge (144b). The ignition charge (46a) has an average particle size of less than 10 microns, or even less than 5 microns, e.g., 1 to 2 microns. The initiation means may include a semiconductor bridge (18) and the ignition charge (46a) may be compacted with a force of less than about 5880 psi, e.g., with a force of 1000 psi.

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Simsbury, CT, United States of America

Brendan M Walsh