In-line initiator and firing device assembly

Details In-line initiator and firing device assembly In-line initiator and firing device assembly

1999-09-28

2001-08-14

Jordan, Charles T. (Department: 3641)

Ammunition and explosives

Igniting devices and systems

Initiating devices

C102S275100

Reexamination Certificate

active

06272996

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to a firing device, and more particularly to an in-line initiator and firing device assembly for use with a shock tube to propagate a percussive signal for firing a remote charge.
An improved output device for firing is also disclosed.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,012,741 to Peebles et al. shows an initiator for a transmission tube comprising a body having a passageway formed therein for retaining an initiator charge and a holder formed within the body for receiving a signal transmission tube and holding a side of the transmission tube in proximity to the initiator charge whereby, upon detonation of the initiator charge, a signal is initiated in the transmission tube through the side of the tube. A primer charge
33
ignites a delay column composition
45
which in turn ignites an initiator charge
41
which pierces the signal transmission tube thereby initiating signal propagation in the tube. While this initiator, by initiating through the tube, maintains the tube sealed against the environment until the moment of initiation, it requires a charge of sufficient strength to rupture the initiation tube.
U.S. Pat. No. 5,365,851 to Shaw shows an initiation fixture for an impulse transmission tube consisting of a sleeve
30
having a longitudinal bore dimensioned and configured to receive a shock tube
10
in one end and a primer cap
28
in the other end. The primer cap
28
and the end of the shock tube
10
are separated by an intervening isolation member
34
which disperses static electricity. The initiation fixture is attached to the shock tube by crimping the sleeve around a closure bushing
36
and optionally provides a stop member
26
to limit the travel of the retaining device
40
. Crimping the initiation fixture onto the shock tube
10
restricts the interior diameter of the shock tube and can lead to failures in igniting the transmission tube.
U.S. Pat. No. 4,272,102 to Burkdoll shows a device for coupling an ignitive reaction or percussive shock wave to a relatively moveable body member such as an airbag mounted on the steering wheel of an automobile. Impact sensors
16
located on the front of the vehicle
11
will initiate shock tube transmission lines
17
-
19
. These shock tube transmission lines will transmit a percussive signal to a gas generator that will inflate an airbag.
U.S. Pat. No. 4,957,027 shows a nonelectric disarmer that uses small arms cartridges that can employ various types of destructive projectiles including water, clay, shot and steel slugs. The force of the shock wave in the shock tube
26
will forcibly strip the piston
50
from the threaded stud
54
attached to the shock tube. The piston is then accelerated down a barrel assembly
52
to fire a primer
34
on small arms cartridge
30
. However, due to the relatively small internal volume of the shock tube, the amount of work energy available from the reaction in the tube is relatively weak so as to limit the effectiveness of such a device.
In view of the foregoing, it is an object of the present invention to provide an in-line initiator and firing device assembly which overcomes the above-mentioned drawbacks and disadvantages to more efficiently provide a percussive signal to a remote charge.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, an initiator device for generating a shock wave through a shock tube includes an end sleeve having an inner surface defining a bore extending between input and output ends. At least a portion of the inner surface of the end sleeve toward the output end is threaded for threadably receiving and forming threads on an outer surface of a shock tube received within the output end. Retaining means are associated with the sleeve for receiving a triggering device for initiating a shock wave and securing the device to the input end of the end sleeve.
According to a second aspect of the present invention, a firing device assembly for receiving a shock wave from a shock tube includes a barrel having an inner surface defining a bore extending between input and output ends. The input end of the barrel is for communicating with a shock tube and the output end is for communicating with a firing device. A firing pin piston is movably disposed within the bore of the barrel, and defines a cavity communicating with the input end of the barrel for storing a propellant charge to be initiated by shock waves from the shock tube. Retaining means is associated with the barrel for coupling the firing device to the barrel.
According to a third aspect of the present invention an in-line initiator and firing device assembly includes a shock tube assembly having an input end and an output end. An in-line initiator is provided for initiating a shock wave along the shock tube assembly. The in-line initiator includes an end sleeve having an inner surface defining a bore extending between input and output ends. At least a portion of the inner surface of the end sleeve toward the output end is threaded and threadably receives and forms threads on an outer surface of the input end of the shock tube assembly. First retaining means is associated with the end sleeve for receiving a shock wave triggering device and securing the triggering device to the input end of the end sleeve. A firing device assembly is provided for being activated by a shock wave transmitted through the shock tube assembly. The firing device includes a barrel having an inner surface defining a bore extending between input and output ends. The input end of the barrel communicates with the output end of the shock tube assembly and the output end communicates with a firing device. A firing pin piston is movably disposed within the bore of the barrel, and defines a cavity communicating with the input end of the barrel for storing a propellant charge to be initiated by shock waves transmitted from the shock tube assembly. Second retaining means is associated with the barrel for coupling the firing device to the barrel.
Preferably, heat shrinkable tubing is applied to the shock tube assembly where it interfaces with the in-line initiator or the firing device to provide reinforcement. Further, heat shrinkable tubing preferably covers the interface of the shock tube assembly with the in-line initiator or the firing device to provide a seal against moisture infiltration.
An advantage of the present invention is that the in-line initiator and firing device is sealed at both ends to prevent moisture infiltration.
Another advantage of the present invention is that the shock tube assembly is coupled to the in-line initiator and firing device without crimping the shock tube assembly which would otherwise impede shock wave propagation.
Other advantages of the present invention will be made apparent in the following description and accompanying drawings.


REFERENCES:
patent: 3260202 (1966-07-01), Bryla
patent: 3411401 (1968-11-01), Harris
patent: 3590739 (1971-07-01), Persson
patent: 3678853 (1972-07-01), Kilmer
patent: 3724383 (1973-04-01), Gallaghan et al.
patent: 3792660 (1974-02-01), Plumer
patent: 3990728 (1976-11-01), Coughlin
patent: 4272102 (1981-06-01), Burkdoll
patent: 4328753 (1982-05-01), Kristensen et al.
patent: 4660472 (1987-04-01), Stevens
patent: 4757764 (1988-07-01), Thureson et al.
patent: 4759291 (1988-07-01), Barker et al.
patent: 4957027 (1990-09-01), Cherry
patent: 5012741 (1991-05-01), Peebles et al.
patent: 5169179 (1992-12-01), Teel, Sr. et al.
patent: 5327835 (1994-07-01), Adams et al.
patent: 5365851 (1994-11-01), Shaw
patent: 5417162 (1995-05-01), Adams et al.
patent: 5597973 (1997-01-01), Gladden et al.
patent: 5614693 (1997-03-01), Welch
patent: 6006671 (1999-12-01), Yunan

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