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EP-3947195-B1 - CORELESS-COIL SHOCK TUBE PACKAGE SYSTEM

EP3947195B1EP 3947195 B1EP3947195 B1EP 3947195B1EP-3947195-B1

Inventors

  • JOHNSON, ALAN L.
  • FRANKLIN, P. CARY

Dates

Publication Date
20260506
Application Date
20200318

Claims (14)

  1. A shock tube package system (20) comprising: a coreless bundle of shock tubing (22) configured to transmit a shock wave to a detonator; characterized in that : a self-adhesive tape covering (28) is wound about at least part of an outer periphery of the bundle of shock tubing, the self-adhesive tape covering (28) forms an outer wrap that envelops an exterior of the coreless bundle of shock tubing (22), and the self-adhesive tape covering (28) comprises one overlapping tape strip that adhere to itself but not to the coreless bundle of shock tubing (22).
  2. The shock tube package system of claim 1 wherein: the coreless bundle of shock tubing (22) is a generally cylindrical coil with a lateral side surface and two end surfaces; and the self-adhesive tape covering (28) covers the lateral side surface and at least part of both end surfaces.
  3. The shock tube package system of claim 2 further comprising: first and second end plates (26a, 26b) respectively abutting the end surfaces of the coil of shock tubing (22) and disposed between the coil of shock tubing (22) and the self-adhesive tape covering (28).
  4. The shock tube package system of claim 3 wherein: the coil of shock tubing (22) defines a longitudinal open interior space (24); the first end plate (26a) has a central opening for accessing the interior space (24); and a first end (30) of the coil of shock tubing (22) is accessible through the central opening of the first end plate (26a).
  5. The shock tube package system of claim 4 further comprising: a shock tube device (34) operably connected to the first end (30) of the shock tubing (22) and tucked into the interior space (24) of the coil of shock tubing (22) through the central opening in the first end plate (26a).
  6. The shock tube package system of claim 5 further comprising: a second shock tube device (36) operably connected to a second end (32) of the shock tubing (22) and attached to an outside of the self-adhesive tape covering (28).
  7. The shock tube package system of claim 6 wherein: the second end plate (26b) is provided with an outer notch (42) for facilitating passage of the second end (32) of the shock tubing (22) between the self-adhesive tape covering (28) and the second end plate (26b).
  8. The shock tube package system of any of claims 6 and 7 wherein: the second shock tube device (36) is attached to the outside of the self-adhesive tape covering (28) by a second covering (38).
  9. The shock tube package system of any of claims 6 to 8 wherein: the second covering (38) comprises self-adhesive tape.
  10. The shock tube package system of any of claims 2 to 9 wherein: the coil of shock tubing (22) defines a longitudinal open interior space (24); a first end (30) of the shock tubing (22) is accessible through the interior space (24); and the system further comprises a shock tube device (34) operably connected to the first end (30) of the shock tubing (22) and tucked into the interior space (24) of the coil of shock tubing (22).
  11. The shock tube package system of claim 10 further comprising: a second shock tube device (36) operably connected to a second end (32) of the shock tubing (22) and attached to an outside of the self-adhesive tape covering (28).
  12. The shock tube package system of claim 11 wherein: the second shock tube device (36) is attached to the outside of the self-adhesive tape covering (28) by a second covering (38).
  13. The shock tube package system of claim 12 wherein: the second covering (38) comprises self-adhesive tape.
  14. A method of manufacturing packaged shock tube package system according to any of claims 1 to 13, the method comprising the steps of: winding a length of shock tubing around a mandrel (44) to form a bundle (22); wrapping a self-adhesive tape covering (28) around at least part of the periphery of the bundle (22); and removing the mandrel (44) from the bundle (22).

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Application No. 16/376078, filed on April 5, 2019. FIELD OF THE INVENTION The present disclosure relates to igniting devices and systems for explosives and, more particularly, to fuse cord and packaging for fuse cord. The following conversion table is used in the present publication: 1 inch = 25.4 mm and 1 foot = 30.48 cm. BACKGROUND OF THE INVENTION Shock tubes are a type of fuse cord or blasting cord used in non-electric blast initiation systems. A shock tube was originally described in U.S. Pat. No. 3,590,739 to Persson. Shock tubing typically comprises an elongated, hollow, flexible, small-diameter tube, the inner surface of which is coated with a reactive substance, for example, a thin layer of detonating or deflagrating explosive composition. Most commonly, this composition consists of a mixture of octogen (HMX) and aluminum powder. Later shock tube designs such as disclosed in U.S. Pat. No. 4,328,753 to Kristensen encompass multiple plastic layers to provide improved tensile strength and abrasion resistance. In commercial blasting applications, the shock tubing provides a signal transmission device to transmit a signal to multiple blasting caps in demolition, mining, quarrying, or other applications, as known in the art. When initiated, the interior coating of the shock tube transmits a low energy shock wave that travels down the interior of the tube, without such shockwave breaching the tube sidewall. A detonator affixed to the end of the tubing is initiated by the shock wave, thereby setting off an attached explosive charge. As known in the art, shock tube-based initiation systems are typically employed and preferred over other systems because of the relative safety and reliability of such systems. The shock tube-based systems are non-electric, and thus are not affected by stray electrical currents, which could cause accidental initiation. Also, the shock tube-based systems do not require special electrical blasting machines, as is required for electric blasting cap systems. In commercial applications, a firing device containing a percussion primer is typically used to initiate the shock tube. For military applications, a self-contained system is desirable. In military systems, an end fitting can be used to position a percussion primer on the end of the shock tube. This type of fitting and initiation system is disclosed in U.S. Pat. No. 6,272,996 B1 to O'Brien et al. In the field, a spring loaded firing pin device is typically attached to the assembly and used to fire the percussion primer for initiating the shock tube. More recently, products have been developed for the military with the firing device permanently affixed to the shock tube lead in the factory. This results in a totally self-contained initiation system being delivered in one package to the field. This type of initiation system is disclosed in U.S. Pat. No. 7,086,335 to O'Brien et al. As disclosed in this application, the firing devices are mounted on the flange of the spool. The shock tubing is wound around the spool and one or more detonators are crimped to the end of the shock tube. US 2006/0144279 A1 teaches a known shock tube package system. Typically, the length of shock tube on a spool can vary from 80 feet to 1,000+ feet. The length of shock tube allows the field blaster to retreat a desired distance between the charge the detonator is initiating and the firing device that initiates the blast. This system is useful and has been deployed extensively in military field applications. However the use of a spool (and, of course, box) greatly increases the overall weight and volume of the shock tube package. For some applications, such as covert operations, it is desirable to have a self-contained detonator assembly that is easily carried by a person or one that will fit into a pocket on a vest. SUMMARY OF THE INVENTION The invention is a system according to claim 1 and a method according to claim 14. The package system includes a "coreless" bundle of shock tubing, by which it is meant that the tubing bundle is not supported or contained by being wrapped around a spool or other supporting structure. The tubing bundle may be a generally cylindrical (in overall shape) coil of shock tubing. Optionally, two washer-like end caps or plates abut the ends of the tubing coil to assist in supporting the coil axially. Also, in an embodiment, a self-adhering overlapping, tape-type outer wrap partially covers the coil and end plates. The tape-type outer wrap may be formed of silicone. Typically, one end of the tubing (referred to herein as the "inner" end) is positioned at the interior of the coil, and the other end of the tubing (referred to herein as the "outer" end) is positioned on the outside of the coil. Optionally, a detonator is attached to the tubing's inner end and is then tucked or moved into the coil, through one of the end plates, for convenient stor