Abstract: A firing circuit that is used for a lightweight launcher for propelling rets is disclosed. The firing circuit generates a pulse for firing the rocket launcher and comprises first and second capacitor banks. The first capacitor bank acts as low impedance energy source, in which power is developed to supply sufficient energy to initiate the rocket motor squib which, in turn, ignites the rocket motor of the rocket. The second capacitor bank acts as a high voltage, low impedance source whose energy is used to charge a capacitor internal to the rocket. The capacitor internal to the rocket, is part of the rocket warhead fuse. The capacitor internal to the fuse is used to initiate the detonator of the rocket warhead when the rocket terminates flight at target.

Abstract: An electronic switch for triggering firing of munitions, the switch inclug an electrical circuit having a high voltage source, a sealed two electrode gap in communication with the high voltage source, a microgap in series with the sealed gap, an exploding foil initiator in communication with the microgap, and an energy storage capacitor bridging legs of the circuit between the high voltage source and the sealed gap. A trigger circuit is in communication with the high voltage source and a fire pulse generator, and is provided with a lead extending from the trigger circuit to one of said legs of said circuit between said sealed gap and said microgap. The energy storage capacitor is charged by the high voltage source to a voltage V which is substantially across the sealed gap. A pulse from the fire pulse generator activates the trigger circuit to provide a high voltage potential V.sub.t across the sealed gap, such that voltage V+V.sub.t breaks down the sealed gap to permit conduction therethrough.

Abstract: An electronic delay igniter including a firing capacitor (102) for storing energy required for firing by applying a voltage from an external power supply, an electronic timer unit (206) provided with a solid state oscillator driven by the energy stored in the firing capacitor (102) to output an output signal after a predetermined delay time, a switching unit (104) for receiving the output signal to transmit the firing energy to an ignition unit (107), and the ignition unit (107) having a ignition charge which ignites on receiving the firing energy, a voltage from the external power supply has a voltage application region where the electronic timer (206) is operated to operate the switching unit (104), but the ignition charge does not ignite even when the energy from the firing capacitor (102) is received.

Abstract: This invention relates to a circuit and method for generating sequential, multiple impulses for use in firing or initiating more than one output device. The invention permits the firing, or actuation, of multiple devices at different times. The disclosed invention is an improvement on existing designs for multiple output impulse cartridges. This multi-output impulse cartridge has self-contained an electrical circuit and electrical energy storage capacitors which allow a single, short pulse of input current to initiate a first output, time out a second or multiple later outputs, and fire the outputs from the remaining energy stored on the capacitors.

Abstract: A sequential blasting system for use in particular in mining comprises a plurality of detonator stages S1, S2, . . . , each of which contains a series circuit consisting of a thyristor T and a detonator means ZE, said series circuit being interposed between two supply leads A, O; B, 0. The signal voltage for the thyristor T in each stage is derived solely from the switching state of the thyristor T of the preceding stage. This causes activation to be transferred from stage to stage independently of the detonator means ZE, in particular irrespectively of whether or not a detonator has been attached and whether or not this detonator becomes highly resistive or not as it should upon being activated. This eliminates the errors that have occurred in known circuits. Upon firing the blasting system, such errors can cause the detonation to occur not only at the first detonator stage, but simultaneously at a location where a detonator is missing as well.

Abstract: The invention is a firing circuit for an exploding bridgewire explosive detonator which is activated only by application of an alternating current of a preselected frequency. The firing circuit comprises a bandpass filter, a voltage multiplier, and a discharge circuit.The invention can be configured to selectively detonate a plurality of exploding bridgewire detonators by assembling a plurality of firing circuits for each exploding bridgewire, each firing circuit having a bandpass filter with a different preselected frequency.

Abstract: A timing and safe module for firing a missile that provides timed DET trir signals in response to a launch signal, a signal indicating that operating voltage is present and a signal indicating proximity to a target, as well as diagnostic signals indicating clock phasing.

Abstract: An input electrical pulse as from an input mechanism is rectified and converted to a direct voltage, which may be regulated in magnitude. The regulated direct voltage may be introduced to a timing circuit which produces a signal after an adjustable and pre-selected delay. This signal causes a circuit to produce a triggering signal. The circuit is biased by a capacitor charged by the direct voltage so that it produces the triggering signal only after the timing circuit has provided the pre-selected delay. The triggering signal closes a switch (e.g. makes a transistor conductive) which provides a low impedance to a firing device such as a squib. The direct voltage then activates the firing device and the firing device actuates an output mechanism. The input mechanism may be coupled to a housing at one position in the housing. When actuated, the input mechanism introduces the input pulse to the circuitry described above, such circuitry being disposed in the housing.

Abstract: An electronic safe/arm device is powered internally by a low-voltage, periodic power source that has insufficient voltage by itself to fire the detonator. The circuit therefore includes a step-up transformer from which sufficient voltage to fire the detonator is obtained. The step-up transformer charges an arming circuit which stores high-voltage power to fire the detonator and also powers the firing circuit which discharges the stored high-voltage energy through the detonator at the appropriate time, to fire the device. The low-voltage, periodic power source may include a low-voltage battery and a dynamic switch for providing periodic pulses of low-voltage energy to the primary winding of the transformer, and the dynamic switch may be powered from the output of the transformer, so that the low-voltage battery has insufficient voltage to power the dynamic switch.

Abstract: A capacitor exploding foil initiator device having a capacitor connected in parallel to a bleed resistor. The capacitor and resistor are connected across an exploding foil initiator by an over-voltage gap switch. When a voltage of the capacitor reaches a breakdown voltage of the switch, the energy stored in the capacitor is discharged through the switch to the exploding foil initiator.

Abstract: Each of first and second switches, preferably ganged, have first and second operative relationships. In the first operative relationship, the first switch is connected across a firing device to prevent the firing device from being energized. In the first operative relationship, the second switch is connected across an energy storage device (e.g. capacitor) to prevent the capacitor from being charged. In the second operative relationship of the second switch, the capacitor is charged by an energy supply device (e.g. battery). In the second operative relationship of the first and second switches, the capacitor is connected in a circuit with the first device and a third switch (e.g. transistor). The transistor is normally nonconductive to prevent the capacitor from discharging through the firing device with the first and second switches in the second operative relationships.

Abstract: A perforating gun using an electrical safe arm device and a capacitor exploding foil initiator device. The capacitor exploding foil initiator device having a capacitor connected in parallel to a bleed resistor which are connected across an exploding foil initiator by an over-voltage gap switch. When a voltage of the capacitor reaches a breakdown voltage of the switch, the energy stored in the capacitor is discharged through the switch to the exploding foil initiator which initiates a detonator cord thereby detonating the shaped charges of the perforating gun.

Abstract: An extended delay detonator (blasting cap) provides a preselected, electronically controlled delay between an incoming non-electric impulse input signal from, e.g., a shock tube or other input transmission line, and detonation of the output charge of the detonator. The delay detonator has a housing closed at one end and open at the other end for coupling to the input transmission line, the signal from which may be amplified by a booster charge mounted within the housing. A piezoelectric generator converts the optionally amplified impulse input signal to electrical output energy. A battery-powered programmable electric delay circuit is activated by the electrical output from the transducer, counts the preselected delay period, and at the end thereof ignites an electrically operable output charge. A method for interposing a preselected delay between the application of a non-electric impulse input signal and the detonation of the output charge is also provided.

Abstract: A digital-to-analog converter provides a dc voltage to a fuze setting circuit which is proportional to the desired delay to be set. A digital controller operates the digital-to-analog converter responsive to the desired firing conditions for the fuze delay circuit. A current driver associated with the digital-to-analog converter converts the applied dc voltage to a constant current source, to charge a timing capacitor of the fuze delay circuit for an initial time interval. At two discrete points during this initial charging interval, the voltage across the timing capacitor is sampled and stored. The sampled voltages are applied to a computation circuit to correct for the variations in capacitance which are represented by this difference.

Abstract: A firing arrangement for initiating a secondary explosive includes a switch, a charge storage circuit for storing an electrical charge, a power supply for charging the charge storage circuit, an initiator electrically connected to the charge storage circuit through the switch, for directly initiating the secondary explosive, and a common unit. The common unit is hand held during initiation and houses the initiator and at least one of the switch, the charge storage circuit, and the power supply. The common unit includes a manual activator for causing discharge of the charge storage circuit through the switch and initiator, to directly initiate the secondary explosive.

Abstract: First and second ganged switches having first and second operative relationships are normally operative in the first relationship and are actuated by an external mechanism to the second relationship. In the first relationship, the first switch shunts and short circuits a pyrotechnic device and the second switch shunts and short circuits an energy storage member such as a capacitor. In the second operative relationship of the second switch, a battery charges the capacitor and also introduces a starting signal to an electronic timing circuit to institute a timing sequencer by the circuit for a pre-selected period that is selected via a series of inputs to the electronic timer. When the pre-selected time period has been timed out, the timing circuit introduces a signal to a solid state electronic switch which is normally in a non-conductive state to prevent actuation. The signal from the timing circuit causes the electronic switch to provide a low impedance.

Abstract: An improved power supply (10) for an electrical circuit (12) mounted on a projectile. The inventive power supply (10) includes a mechanism (14) on the projectile for generating electrical energy on the acceleration thereof. The energy is stored and released to a load on the deceleration of the projectile. In a particular implementation, the energy producing mechanism (14) is a piezo-electric transducer. Storage of electrical energy in the transducer is facilitated by the connection of a diode (16) across the output terminals thereof. An acceleration switch (18) is provided which is mounted on the projectile to be open on acceleration and closed on deceleration thereof. The switch (18) thereby releases a predetermined amount of stored energy to the load (12) only on the impact of the projectile with an object.

Abstract: The invention relates to a blasting apparatus for activating a plurality of electrical detonators after predetermined time delays. The blasting apparatus includes a plurality of remote electrical delay devices. Each device is linked to a detonator, and is arranged to be serially programmed with a timing signal, which originates from the central control unit and which determines the time delay. A bidirectional signal harness, having ends which terminate at I/O ports in the control unit, serially links the delay devices to the control unit. In the event of a fault of discontinuity occurring in the harness prior to programming of the delay devices, the discontinuity is detected and the direction of programming along the bidirectional harness is reversed so that those delay devices which, due to the break, cannot be programmed in the initial direction, are programmed with timing signals travelling along the signal line in the opposite direction.

Abstract: An apparatus for detonating explosive charges at a given location in response to an initiation at a remote location and after a preselected delay comprises a non-electrical initiation device for generating a non-electrical energy input by detonation or pyrotechnical combustion at the given location and initiated at the remote location, and an electrical igniter also at the given location responsive to the initiation device for time-delayed ignition of the explosive charge. The electrical igniter includes a transducer for generating an electrical output signal in response to the non-electrical energy input, an electronic variable time delay igniter in close proximity to the transducer for setting a preselected time delay and for generating a time delayed electrical output signal and an igniter also in close proximity to the electronic time delay means for initiating the ignition of the explosive charge.

Abstract: A timing circuit includes a variable frequency oscillator which has a control signal that determines the output frequency of the oscillator. The control signal and a reference signal are stored in the circuit. A precision calibration pulse is applied to the timing circuit which counts the output cycles of the variable frequency oscillator during the period of the pulse. This count is stored and compared to the reference count to produce an error count. This error count is combined with the previously stored control signal to produce a new control signal that drives the output of the oscillator to a new frequency. The timing circuit can be utilized as a part of a delay circuit is an electronic blasting system wherein a control unit transmits the calibration pulse concurrently to each of the delay circuits to cause each circuit to calibrate its local oscillator in accordance with the calibration pulse. The control unit transmits a delay count to each of the delay ignition circuits.

Abstract: A base mounted remote set digital time fuze permits a chambered round to e power, time setting information and cartridge case firing voltage available at an electric primer terminal of the cartridge case. Fuze power, time setting information and cartridge firing are performed sequentially over the same hardwire line.

Abstract: A new shape charge includes an integrated circuit semiconductor bridge detonating device responsive to ordinary current for triggering a switch in the detonating device and igniting a pyrotechnic composition on a small integrated circuit semiconductor bridge in the detonation device in response to the current, thereby igniting an explosive material in the shape charge and firing the shape charge. Since the integrated circuit detonating device is utilized, responsive to ordinary current for detonation, prior art detonating cords are not needed. A plurality of shape charges in a perforating gun are fired substantially simultaneously using the new shape charge of the present invention.

Abstract: A modular electronic safe arm device (MESAD) (10) for arming and igniting an explosive is universal in application and employs a standard circuit architecture which uses application specific logic modules (12) and (14), a standard voltage control module (16), and standard high energy firing modules (18) and (20). In the preferred embodiment, the logic modules (12) and (14) are state machines using clocked sequential logic and having read-only-memories. The logic modules (12) and (14) generate dynamic arming signals at outputs (54) and (76) which cause the voltage control module (16) in conjunction with transformer (102), to convert a low voltage input (98) to a high voltage output (100). The high voltage output (100) is used to charge firing capacitors (112) and (138) in standard high energy firing modules (18) and (20). Logic module (14) generates two trigger signals at outputs (76) and (78) for activating the trigger modules (126) and (148).

Abstract: A circuit arrangement for electrically firing a load, such as the rocket motor of a projectile, at a predetermined time after it has been ejected from a predetermined path (such as the barrel of a gun) comprises a capacitor which is charged up through bore-rider contacts sensing ejection of the projectile, a resistor and two diodes. A further diode blocks a capacitor discharge path in which the load is connected. Closure of the bore-rider contacts initiates two timers. These are of different type, so as to minimize the risk of double failure, and have the same predetermined time period. At the end of this period, they respectively close switches which abruptly shifting the potential on the positive plate of the capacitor to zero. The diode 32 in the capacitor discharge path is now unblocked and discharge current passes through the load and fires it.

Abstract: Disclosed is a device enabling the selective, simultaneous triggering of high energy detonators, using no sensitive pyrotechnical device, such as exploding wire detonators or slappers. The device comprises, for each of the detonators, an electrical triggering chain comprising a capacitor used to deliver energy sufficient to trigger each of the detonators. It comprises a single energy source generating a pulse and a single switch to apply the pulse to each electrical triggering chain. Means to inactivate the corresponding chain are applied before the commutation of the switch so as to make those detonators that are not to be triggered inoperative.

Abstract: An electric detonator of delay type including leg wires connectable to bus wires, a capacitor connected across the leg wires for storing the electric energy supplied from an electric blaster via the leg wires, a delay circuit connected across the leg wires and generating an igniting signal at a predetermined timing, a switching circuit and an igniting resistor connected to the switching circuit, whereby the switching circuit is made conductive in response to the igniting signal to discharge the electric energy stored in the capacitor through the igniting resistor to explode the detonator. In order to operate the detonator reliably and safely, there are provided low and high voltage protection circuits for discharging the electric energy therethrough when the power supply voltage is out of a predetermined normal operation range.

Abstract: A back-up electrical safety device for a land mine is presented which proes an additional 50 to 60 second time delay concurrent with the conventional built-in one minute delay before any detonation is possible. A soldier is therefore afforded an additional assurance of an ear one minute time lag before an accidental explosion could be possible due to premature pulsing of the mines's built-in timer. A Darlington pair RC switching circuit appears electrically in tandem between the internal timer and the various arming means, to doubly insure an approximate one minute override before detonation. This dual safety feature permits hand-emplacement, over gun-launching, of a conventional land mine.

Abstract: A system is provided for initiating a blasting cap wherein pulsating light energy is converted to electrical energy. An optical coupler couples the source of energy to a remote firing arrangement to transfer the generated pulsating light energy to the firing arrangement. An electrical connection connects the firing arrangement to an ignition resistor in a detonator. Thus, the generated light energy is converted to electrical energy and is transferred to the ignition resistor, the transferred electrical energy being the firing energy for the ignition resistor.

Abstract: A torpedo ejects lead weight at the conclusion of a practice run and is bed to the surface for recovery and reuse. A squib is initiated to release the weight by a control circuit which is actuated when the torpedo engine stops. An appropriately interconnected transistor and field effect transistor respond to built-up charges on three charge storage circuits to assure the proper initiation of the squib when the torpedo stops running. The stored energy thus is brought into effect to assure reliable separation and avoids the problems otherwise associated with conventional electromechanical relays.

Abstract: A swimmer distress signal of the smoke or flare type has an ignition system hich can be operated with one hand. A stab primer is activated by a sliding firing pin that is normally locked in position and protected by a metal cover. Upon withdrawal of the signal from a pouch, a lanyard pulls off the cover to expose and unlock the firing pin which has an enlarged head. A hit or force on the firing pin head drives it into the primer to ignite the display.

Abstract: A plurality of electric blasting caps are fired through the ignition system which includes a transformer having a primary winding and a secondary winding. The secondary winding of the transformer is connected to the resistive elements of the blasting caps through a blasting circuit which is electromagnetically coupled to the resistive elements of the blasting caps via a small toroid transformer. A D.C. voltage is stored on a storage capacitor which has one end connected to the center point of the primary winding. The other ends of each half of the primary winding are connected through a driver circuit to ground. Each driver circuit is enabled by a flip-flop at predetermined intervals, whereby the storage capacitor will discharge through the appropriate half of the primary, to thereby produce a pulse train at the output of the secondary. The pulse train provides the ignition power for igniting the electric blasting caps.

Abstract: An electronic delayed-action explosive detonator comprising a tubular case, a capacitor chargeable by pulses from a blasting machine, an integrated circuit for processing pulses from the blasting machine to set a delay time, the integrated circuit controlling the elapse of the delay time after the delay time has been set, a primer to which current is supplied upon elapse of the delay time for enabling detonation, and detonator wires extending from the tubular case for enabling connection of the blasting machine to at least one of the capacitor and integrated circuit. A supporting plate arrangement for carrying the integrated circuit is disposed in series with the capacitor within the tubular case. The supporting plate has a first contact area with connecting pads for enabling attachment of leads of the capacitor, and a second contact area with connecting pads for enabling attachment of the detonator wires which are within the tubular case and extend outwardly therefrom.

Abstract: A seismic geophysical prospecting method and apparatus is described involving the sequential shooting of lump explosive charges spaced apart in a borehole so as to produce seismic wave reinforcement in a given direction. Fast acting electronic switch means control the detonation of each charge responsive to the advance of the seismic waves front substantially independent of formation pressure wave velocity.

Abstract: Low level remotely generated control signals are amplified at a local ignition site using a local power source and the amplified control signals are used to charge a local energy storage device. Thereafter firing control signals (e.g., controlled duration suppressions of the remotely generated control signals) are detected and used to control discharge of the thus stored energy through an electrical ignition device.

Abstract: A detonation system for use with supply of electrical energy has user operable firing console for selectably transmitting unit identification information, firing delay time information and selections from a command set including Output, Delay, Fire (Time), Abort, Power Up (Arm), Input, and Store. The console displays responses or information digested from responses by electrical delay detonators to the commands. The detonators have explosive, a capacitor for storing energy from the supply to set off the explosive, circuitry for charging the capacitor from the supply and transferring the energy from the capacitor to the explosive in response to first and second signals generated in response to the commands. Each detonator can be programmed with a unique identification number and delay time. The time base in each detonator can be compensated so that errors in the time base are obviated so as to achieve the correct delay.

Abstract: An air driven electrical generator, carried by a weapon, supplies low voltage electrical energy to a storage capacitor which in turn supplies reoccurring constant amounts of electrical energy to the primary of a flyback transformer. The secondary of the flyback transformer supplies relatively high voltage electrical energy to a slapper detonator capacitor.

Abstract: An electronic ignition control circuit, including a logic circuit which is powered from a power supply source, for the obtaining of an ignition clearance signal from a combination of ignition clearance signals from a combination of ignition sensor signals, and including an electrical detonator which is ignitable through the intermediary of a switching element which is electronically reversible responsive to the ignition signal.

Abstract: An electronic delay detonator actuated after the lapse of a predetermined delay time from the application of an input power source, comprises a capacitor for storing the electrical energy supplied from the input power source, a diode bridge for preventing the stored electrical energy from being released reversely toward the input power source, a CR oscillator, a counter for generating a signal upon having counted a pulse signal produced from the CR oscillator by a predetermined number, and a thyristor driven by the signal for supplying the electrical energy stored in the capacitor to an ignition device in the detonator, the delay time being accurately determined by counting the pulses generated from the CR oscillator.

Abstract: A high energy switching circuit for an initiator, for example, an exploding bridgewire (EBW) or slapper-type detonator, includes a charged capacitor which is placed across a pair of series diodes connected in a reverse standoff voltage mode with respect to the capacitive voltage in series with an EBW initiator circuit. A switching field effect transistor is connected in shunt across the lower diode. In the armed condition, the pair of diodes clamp the high energy capacitor voltage at their reverse avalanche voltage. Upon the activation of the switching transistor, the capacitor voltage is impressed across the upper diode and a high reverse current flows through the upper diode placing it in destructive conduction which immediately also forces the other diode into destructive conduction to complete the series circuit from the capacitor to the EBW or slapper detonator. The circuit comprises low cost components and features very good firing simultaneity between similar firing circuits.

Abstract: A circuit for providing controlled switching of power applied to a load is adapted for actuating and deactivating a power switching circuit in response to a command signal. The circuit employs a switching circuit having a time delay section operable to terminate application of power immediately upon the cessation of a control signal and to conduct current after a predetermined delay interval after receipt of a command signal. The circuit is adapted for use with pyrotechnic ignition systems in which it is desired to quickly discharge capacitive elements connected to a load for prevention of undesired and possibly hazardous build-up of heat in a resistive ignition element.

Abstract: For small calibre projectiles the electrical energy needed for igniting a low-ohm ignition capsule is stored in a supply or ignition capacitor which, upon firing of the projectile, is charged by a current generator. To ensure that during charging of the supply capacitor upon firing of the projectile, the ignition capsule does not prematurely ignite, there are provided safety circuits, in particular a static blocking circuit, a dynamic blocking circuit and a static delatching circuit.

Abstract: An electronic safe and arm device for generating a trigger signal for initiating detonation of a flying plate detonator. A toroidal trigger capacitor surrounds the electronics of the device and will be shorted to disable the safe and arm device if damage occurs thereto. First and second sensor switches responsive to selected flight parameters control the charging of the trigger capacitor. A normally closed arm enable switch prevents the charging of the trigger capacitor until after break-wire launch has occurred.

Abstract: An electronic switch for projectiles includes a circuit with a source of electric energy which is switched in when the projectile is discharged. The circuit includes an adjustable time-delay device for the explosion of the projectile, a device for preventing muzzle burst, and a self-destruct arrangement. The exploding fuse is connected to the source of energy by an impact or a proximity switch. The self-destruct arrangement is settable by cooperating cells carried by the projectile and by the barrel of the gun.

Abstract: Electric circuit for firing a detonator for a projectile, comprising a generator for charging a first condenser and a second condenser connected in series, the aforesaid first condenser being connected in series with a contactor, a primer and a semi-conductor component with a controlled conductibility, and means for stabilizing the voltage of one of the aforesaid condensers and for preventing the firing of the primer during a predetermined time, in which the aforesaid means comprise a first voltage divider connected in parallel with the series connection of the aforesaid first condenser and second condenser and aforesaid contactor, the control electrode of the aforesaid semi-conductor component being connected with the intermediate point of the aforesaid first voltage divider comprising a transistor, the base of which is connected with the intermediate point of a second voltage divider connected in parallel with the aforesaid second condenser, the capacity of which is many times greater than the capacity of t

Abstract: A dual output simultaneous firing circuit which provides a means for explng fuse wires with a simultaneity of 20 to 200 nanoseconds even though the breakdown voltages of the fuse safety gaps have a large disparity. A DC voltage charges high voltage capacitors. When the charge voltage reaches the lower breakdown voltage of one safety gap, that fuse explodes. A balancing transformer induces momentarily an equal voltage which adds to the existing voltage on the undischarged capacitor. The additional charge breaks down the other safety gap causing the other fuse to explode.

Abstract: An electric detonator cap has a casing, which accommodates an explosive detonator charge, an electrically ignitable means for firing the detonator charge, a chargeable and dischargeable electric energy source for igniting the firing means, and an electric circuit arrangement, including a controllable switch means connected between the energy source and the firing means, an electric delay circuit, and a decoder. The energy source is connectable via connecting wires extending out from the casing, to an electric current source for charging the energy source, and the decoder is electrically connectable to said connecting wires and is adapted upon receipt of a specific electric firing command signal supplied through said connecting wires to actuate the delay circuit in a manner to close the switch means after a predetermined delay time.

Abstract: An electronic ignition circuit for the self-destruction of a projectile fuse, including a voltage source and a charging condenser determinative of the time interval until self-destruction. A threshold switch is responsive to a predetermined minimum voltage at the charging condenser for igniting an igniter, and an electronic control circuit is connected between the voltage source and the charging condenser.

Abstract: A bridging plug for a circular blast hole has a relatively longer major axis and a relatively shorter minor axis. The plug is hinged to pivot about the minor axis. A tension line is secured to the minor axis for lowering the plug into an explosive placement hole. The plug pivots into an angular open position when lowered into the hole. An upward force on the tension line jams the hinged portions of the plug in a closed position to plug the hole. An explosive charge can be placed in the hole at the location defined by the closed plug.

Abstract: A cased borehole has a tubing string run downhole thereof. A packer affixed to the tubing is set with the tubing string terminating in proximity of a hydrocarbon producing formation to be completed. A wireline operated perforating gun is suspended from a mass by means of a lost motion coupling and the mass is suspended from a wireline. The entire apparatus is run downhole and positioned adjacent to the hydrocarbon containing formation. The gun is detonated; whereupon formation fluid enters the casing and tends to thrust the gun uphole respective to the mass and to the wireline. The relative motion between the gun and mass is advantageously used to set a tool hold down apparatus which arrests uphole thrust of the gun. The gun can be subsequently retrieved by lifting the mass with the wireline, thereby releasing the tool hold down apparatus and enabling wireline retrieval of the entire apparatus suspended from the wireline.

Abstract: In an electrical detonator, an electrical circuit includes a network for rging the fire pulse capacitor. After battery activation and gun launch, but before arming, the circuit (via an n channel MOS transistor within the CMOS) operates to ground the fire pulse capacitor. At "arm minus 50 msec", the n channel is turned OFF and the p channel transistor is turned ON. This charges the fire pulse capacitor to the battery voltage within 50 msec. The CMOS issues an "ARM COMMAND" to fire the piston actuator (PA) discharging the fire pulse capacitor until PA fires. The fire pulse capacitor is recharged in the 50 msec interval between ARM and FIRE. Logic within the CMOS is used to monitor the fire pulse capacitor. These circuits will detect premature voltage on the fire pulse capacitor and DUD the fuze.