US 3703145 A
An ordnance fuze having a detonation option selection circuit, an arm circuit and a detonation circuit. The detonation options are selected by option circuits responsive to a particular voltage magnitude and polarity to provide output signals which actuate a plurality of switches to select an energy path to the detonator. The paths may include timing circuits to allow detonation of the fuze after the occurrence of a sensed condition. The condition may be sensed by an impact switch or by a target detecting device. The arm circuit includes time delays, a delivery mode sensing device, safety devices and switches to arm the fuze at a time dependent on the delivery mode of the fuze.
Description (OCR text may contain errors)
United States Patent Burkhardt et al. 1 Nov. 21, 1972  SELECTIVE ARMING MODE AND 3,275,884 9/1966 Segall et al ..102/70.2 X DETONATION OPTION ORDNANCE 3,470,419 9/1969 Sitler et al ..102/70.2 x
Inventors: Lawrence E. Burkhardt, Burtonsville; Charles H. Johnson, White Oak, both of Md.
The United States of America as represented by the Secretary of the Navy Dec. 5, 1969 App]. No.: 882,572
References Cited UNITED STATES PATENTS 3/1970 Lauro ..89/l.814
Primary ExaminerBenjamin A. Borchelt Assistant Examiner-Thomas H. Webb Attorney-R. S. Sciascia and J. A. Cooke [S 7] ABSTRACT An ordnance fuze having a detonation option selection circuit, an arm circuit and a detonation circuit. The detonation options are selected by option circuits responsive to a particular voltage magnitude and 7 Claims, Drawing Figures SAFETY 94' DEVICE- ACCELER- 2 OMETER v OPTION P 56 -ROTOR Q /2 I J REGU- TIMER I L OPTION OPTION LATOR (TDI) I I 76 72 I 22 72m ENERGY IMPACT WITCH l STORAGE 38 54 s I I 68 92 55 66 62 l 1x 70 1 I I FUNCTION ..LZ EXPLOSIVE g; -0 o- TIMER DETONATOR TRAIN STORA ..R (T04) I I TARGET FUNCTION DETECTING TIMER l DEVICE (T03) 42 SELECTIVE ARMING MODE AND DETONATION OPTION ORDNANCE FUZE BACKGROUND OF THE INVENTION This invention relates generally to ordnance fuzes and more particularly to an ordnance fuze providing a plurality of arming modes and detonation options.
Present day ordnance fuzes have been devised which provide a plurality of arming modes and detonation options. These prior art ordnance devices have been somewhat unsatisfactory, however, because they make use of radio frequency (RF) to select the desired arming or detonation option and, therefore, are somewhat complex, expensive, voluminous or otherwise undesirable. Furthermore, existing ordnance fuzes have been unable to provide the number of fuze options and anning modes desired under various military tactical situations. Additionally, those providing a plurality of arming modes must be manually selected thereby increasing the chance of human error or the like.
SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide an ordnance fuze having a plurality of arming modesand detonation options.
Another object of the present invention is to provide an ordnance fuze that is automatically armed, dependent on the delivery mode, thereby precluding the chance of human error.
A still further object of the instant invention is to provide an ordnance fuze whose detonation options are selectable by utilizing direct current voltages.
Another object of the instant invention is to provide an ordnance fuze that is both compact and reliable.
Briefly, these and other objects of the present invention are attained by providing an ordnance fuze having a plurality of arming times dependent on the delivery mode of the fuze and a plurality of detonation options dependent on the polarity and magnitude of direct current voltages applied thereto.
BRIEF DESCRIPTION OF THE DRAWING A more complete understanding of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
FIG. 1 is a block diagrammatic view of the ordnance fuze according to one embodiment of the present invention;
FIGS. 20, 2b and 3 are circuit schematic views of various components of the ordnance fuze embodied in FIG. 1; and
FIG. 4 is a graphical view of the time relationship of the arming modes and fuze options of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, wherein like reference numerals designate corresponding parts throughout, and more particularly to FIG. 1 thereof, the ordnance fuze is shown as including an input ter- 0 voltages +V1, Vl, +V2 and V2 may be available from the ordnance delivery vehicle to be selectively applied to the fuze.
A plurality of fuze option circuits 12, 14, 16 and 18 each corresponding, respectively, to a particular DC voltage selectively available from the ordnance delivery vehicle are connected to terminal 10. More specifically, option circuit 12 is responsive to the selection of -V2 volts on the fuze function control panel and available at terminal 10, option circuit 14 is responsive to the selection of +V1 volts on the fuze function control panel and available at terminal 10, and
A regulator 20 is connected to terminal 10 to provide a predetermined voltage to energy storage devices 22 and 24 coupled thereto regardless of the magnitude and polarity of the voltage selectively available at terminal 10. By way of example, the energy storage devices may be capacitors and the regulator may be 0 that disclosed in application, Ser. No. 584,61 l, filed Oct. 5, 1966, for High Voltage Regulator For A Capacitive Load by L.E. Burkhardt, C.I-I. Johnson and BF. Branagan now US. Pat. No. 3,505,583.
Connected to -V2 option circuit 12 is a switch actuator, such as an explosive switch 26 adapted, as hereinafter more fully explained, to be actuated by option circuit 12 in the directionof arrowhead 28 to open normally closed electrical contacts 30 and close normally opened electrical contacts 32, ganged for movement in unison. Similarly, a switch actuator, such as an explosive switch 34, is connected to the outputs of the +Vl and +V2 option circuits, 14 and 16, respectively, and is adapted when actuated to close normally open contacts 36 and open normally closed contacts 38, ganged for movement in unison, as indicated by arrowhead 40. It is readily apparent that other types of switches may be utilized. Thus, switches 26 and 34, as well as the other switches to be more fully described hereinafter, may be electromechanical relays or semiconductive switch elements, or the like.
The output of +V2 option circuit 16 is also connected to a target detecting device 42. The target detecting device may be any electronic or other device adapted to be activated either electrically at a lead 44 or mechanically as indicated at 46 to give a firing signal at its output 48 when the ordnance device approaches a target. The target is normally described as ground in the case of a bomb but may be any material object capable of reflecting a radiated signal (not shown) transmitted from the target detecting device 42. Such target detecting devices are well known in the art.
A terminal 50 is coupled to the output of V1 option circuit 18 which may be connectable to any desired circuit, such as signal circuit or the like, or may be merely connected to ground. As hereinafter elaborated, the selection of V1 volts does not actuate either switches 26 or 34 and, therefore, the respective switch contacts 38, 32, 36 and 38 remain in the positions as shown.
As hereinabove explained, the selected voltage +V1, V1, +V2 or V2 actuates its corresponding option circuit and, dependent on what voltage is selected, actuates switches or signal circuits or the like connected thereto to determine the detonation option of the fuze.
The output 48 of target detecting device 42 is connected to an impact switch 52. Impact switch 52 may be a trembler switch or the like adapted to close upon impact of the fuze and target. Such switches are well known in the ordnance fuze art. One side of the impact switch is connected, via normally opened switch contacts 54 actuated as hereinafter explained by a rotor 56, and, via normally closed contacts 38 of switch 34, to a switch actuator such as an explosive switch 58. Ex-
plosive switch 58, when energized, actuates normally opened contacts 60, as shown by arrowhead 62, to complete a path from energy storage device 24 through normally closed contacts 30 to a function timer 64. An alternative path may be completed from energy storage device 24 and contacts 60 to a function timer 66 when normally opened contacts 32 are closed by the actuation of explosive switch 26. As hereinafter more fully explained, function timers 64 and 66 may provide a time delay of TD3 and TD4, respectively, between discharge of energy storage device 24 and the supply of the energy thereof to a detonator 68 coupled to the function timers by normally opened contacts 70 of rotor 56. By way of example, function timers 64 and 66 and the arm timers to be hereinafter described may be similar to those disclosed in U.S. Pat. application, Ser. No. 677,295 for Method and Apparatus For Providing Electrical Energy To A Load With A Predetermined Time Delay, filed Oct. 23, 1967, by LE. Burkhardt and C. H. Johnson, now U.S. Pat. No. 3,500jl64.
Connected to the junction of the other side of impact switch 52 and energy storage device 22 are normally closed contacts 72 which complete an energy path from energy storage device 22 to an arm timer 74 by way of normally closed contacts 76. An alternate path may be completed from energy storage device 22 via contacts 72 to an arm timer 78 when normally opened contacts 80 are closed and normally closed contacts 76 are opened responsive to actuation of an explosive switch 82 which operates in the direction of arrowhead 84. Contacts 76 and 80 are ganged for movement in unison.
An abort circuit 86 is coupled to arm timer 78 and, as more fully explained hereinafter, renders the arm timer ineffective if fuze impact occurs before arming when the ordnance device is in an unretarded mode of operation. By way of example, abort circuit 86 may comprise an impact switch which discharges a primary timing capacitor (not shown) in timer 78 upon impact. Thus, in the case of a bomb, or the like, delivered by an aircraft, an inadvertent impact may close impact switch 52 and cause detonation of the bomb upon arming. Since the path of the bomb in its unretarded delivery mode follows, initially, the path of the aircraft, arming after inadvertent impact may cause the bomb to explode while still near the path of the aircraft possibly causing damage to the aircraft. The arm abort circuit, by rendering timer 78 ineffective upon inadvertent impact precludes such a possibility. It may not be required to have the impact before-arm abort in the case of a retarded mode of delivery since, in this case, the bomb does not follow the aircraft path and premature detonation upon arming is less likely to cause aircraft damage. It is readily apparent, however, that abort circuit 86 or an additional abort circuit may be connected to arm timer 74 to act as an impact-before-arm abort when the bomb is in its retarded delivery mode if desired.
As hereinafter more fully explained, arm timers 74 and 78 provide time delays TDI and TD2, respectively, between the transfer of energy from energy storage device 22 to rotor 56. Energization of rotor 56 operates to close contacts 54 and and open contacts 72 as shown by arrowhead 88. As indicated by mechanical linkage 90, energization of rotor 56 also operates to align detonator 68 with an explosive train 92 for explosion of the ordnance device in any manner well known to those in the ordnance fuze art.
A safety device 94 is connectable by a mechanical linkage 96 to a lanyard (not shown) or other sensing mechanism on the ordnance delivery vehicle, such as an aircraft in the case of a bomb. Upon separation, or any other desired sensed condition, between the ordnance delivery vehicle and the ordnance device, safety device 94 operates to unlock rotor 56 as schematically indicated via linkage 98. Furthermore, as hereinafter'more fully explained, the safety device includes an accelerometer which detects whether the bomb is in its retarded or unretarded mode of operation and, dependent on the particular delivery mode, actuates a switch 100 from a contact to a contact 112 as shown by arrowhead 113. By way of example, safety device 94 may be similar to that disclosed in U.S. Pat. No. 3,316,841 for Safety Device For A Bomb Fuze and issued to CE. McFann and AS. Munach.
Referring now to FIGS. 2(a) and 2(b), the positive voltage responsive and the negative voltage responsive option circuits are shown, respectively. A terminal 1 14, in FIG. 2(a), is shown as connectable to the available positive voltage, +Vl or +V2, available from the ordnance delivery vehicle. The available voltage is passed, via a resistive impedance element, such as resistor 116, to be stored in an energy storage element, such as a capacitor 118. A unidirectional semiconductive element, such as a diode 120, is connected between resistor 116 and capacitor 118 and is properly poled to block any negative voltage from the capacitor. Upon receipt of energy of a proper polarity and magnitude at terminal 114, capacitor 118 charges through resistor 116 and diode 120 until the breakdown voltage of a breakdown device, such as a cold cathode diode 122 or the like, is reached. At this time, capacitor 118 discharges through breakdown diode 122 and activates explosive switch 34 connected thereto for actuation of the proper contacts as'shown in FIG. 1. A resistor 124 is parallel connected across the capacitor to bleed off any residual charge on capacitor 118. By way of example, the breakdown voltage of diode 122 is chosen below that of the applied voltage at terminal 114 to insure that sufficient energy is available on capacitor 118 to fire the diode.
The negative voltage responsive option circuit shown in FIG. 2(b) is similar in operation to the circuit of FIG. 2(a). A terminal 126 is connectable to a negative available voltage, such as V1 or -V2, and, via a path including a resistor 128 and a properly poled diode 130, charges an energy storage device, such as a capacitor 132. The capacitor is charged until the breakdown voltage which is less than the voltage supplied at terminal 126 of a breakdown device, such as a cold cathode diode 134, is reached. In the case of --V2 option circuit 12, conduction of diode 134 allows the capacitor to discharge through a path including explosive switch 26 for actuation of contacts 30 and 32 as shown in FIG. 1. As shown in FIG. 1, the discharge path of capacitor 132 for the -V1 option circuit 18 includes a terminal 50 which is connectable to any desired function circuit such as a signal device or the like. A resistor 136 connected in parallel with capacitor 132 serves to bleed off any residual charge on the capacitor.
Rotor 56 and detonator 68 are schematically shown in FIG. 3. As shown therein, rotor 56 includes parallel connected explosive bellows drivers 138 and 140 connected, respectively, to a center-tapped transformer, such as an autotransformer 142 or the like, having windings 144 and 146 of approximately equal mutual inductance and polarities as shown. The force required to move the rotor into its armed position, more particularly to move detonator 68 in alignment with the explosive train, is provided by the explosive bellows drivers. A switch 148 is parallel connected across detonator 68 to short the detonator during fuze assembly or handling to thereby act as a safety device. When the rotordetonator is assembled into the fuze body, the switch is opened.
Under normal operation, transformer 142 allows the available energy from terminal 112 to be equally shared between the two explosive bellows drivers. The transformer also serves to isolate the two bellows drivers and prevent the shunting of all available energy to ground (not shown) or the like if one of the drivers is accidentally shorted. More particularly, a short in explosive bellow driver 140 or the lowering of its resistance, which might occur during assembly or arming initiation, would normally shunt all available energy away from explosive bellow driver 138 and preclude desired rotor operation. Due in part, however, to the relative polarities of windings 144 and 146, a short in driver 140 will cause an aiding voltage to be enduced in winding 144 causing an increased energy flow in driver 138. Thus, a short or the like in driver-140 will not divert energy from driver 138 but will, in fact, increase the energy flow therethrough.
The operation of the invention may best be understood by reference to FIG. 1 and FIG. 4 of the drawing. As hereinafter explained, the arming mode, that is the time between separation of the ordnance device from the ordnance delivery vehicle and arming of the ordnance device, is selectively varied dependent on the delivery mode of the ordnance device. Thus, in the case of a bomb released from an aircraft, the arming time varies depending on whether the bomb is retarded or unretarded.
Similarly, a plurality of detonation options are available and are dependent on the voltage supplied to terminal and the mechanical or electrical initiation of target detecting device 42. As further explained, the detonation options include impact, impact plus time delays, target detection, target detection plus time delays and impact backup for the target detection optrons.
In time sequence of operation, the detonation option is chosen and the selected detonation path is partially completed while the bomb is on the aircraft. Upon separation of the bomb and the aircraft, the bomb is armed thereby further completing the selected detonation path which is then fully completed upon the occurrence of the selection detonation condition such as bomb impact or the like.
The operation of the ordnance fuze may be more readily understood by referring to the arm mode of operation, it being noted, however, that arming occurs subsequent to the detonation option selection time sequence. On weapon release, the removal of the lanyard (not shown) starts the safety device-accelerometer 94 as indicated by linkage 96. The accelerometer senses whether the bomb is in its retarded or unretarded mode of operation and, as hereinafter more fully explained, this determines the time that switch 100 is translated from contact 110 to contact 112.
Upon release of the weapon at t= T (see FIG. 4), energy storage devices 22 and 24 are charged to a constant voltage from terminal 10 via regulator 20. Energy storage device 22 starts to discharge through contacts 72 and 76 and through arm timer 74. If the weapon is retarded, safety device 94 functions almost immediately, at t T, after release, to unlock rotor 56 as indicated by linkage 98 and to translate switch 100 from contact 110 to contact 112. As hereinbefore mentioned, arm timer 74 provides a time delay TD1 for the discharging energy from storage device 22. Thus at t TD1 the energy flow from storage device 22 completes its discharge from the storage device, contacts 72 and 76, arm timer 74, switch 100 and contact 112 to rotor 56. Initiation of rotor 56 arms the bomb by moving the detonator 68 in alignment with explosive train 92 and also opens contact 72 and closes contacts 54 and 70 as shown by arrowhead 88. The opening of contact 72 stops the energy discharge from storage device 22 by opening the discharge path and, as hereinafter explained, the closing of contacts 54 and 70 partially completes an electrical energy path to detonator 68. Thus, when the bomb is in its retarded delivery mode, arming is effected at t= TD1.
If the bomb is unretarded, the rotor is not unlocked nor is switch 100 translated until t T wherein T TD1. Thus at t TD1 switch 100 remains on contact 110 and energy storage device discharges through timer 74 and contact 110 to explosive switch 82. Initiation of explosive switch 82 opens contacts 76 and closes contacts 80 so that energy storage device 22 continues to discharge through a new path including contacts 72, contacts 80 and arm timer 78. Arm timer 78 provides an additional time delay TD2 for the energy flow of storage device 22. At t= T safety device 94 unlocks rotor 56 and moves switch to contact 1 12. It is readily apparent from FIG. 4 that T T T wherein T TD1 TD2. Thus, the additional time delay TD2 provided by timer 78 allows safety device 94 to translate switch 100 from contact 1 10 to contact 112 prior to an output from timer 78. At t T the discharge from energy storage device 22 flows out of timer 78 to contact 112 and rotor 56 to arm the fuze. Thus, when the bomb is in its unretarded delivery mode, the arming occurs at t T; and an arming delay TD1 +TD2, equal to the sum of the delays of timers 74 and 78, respectively, is obtained. As hereinbefore explained, an abort circuit 86 is coupled to timer 78 to render timer 78 ineffective between t TDI and t T, when the bomb is in its unretarded mode if an inadvertent impact occurs before the arm sequence has been completed. Thus, the ordnance device is provided with arming times automatically dependent on the delivery mode, that is, arming times t=TDl and t=TDl TD2 when the bomb is in its retarded and unretarded delivery modes, respectively.
As hereinbefore explained, the detonation option is chosen while the bomb is on the aircraft and is dependent on the magnitude and polarity of the voltage available at terminal 10 as well as the mechanical or electrical initiation of target detecting device 42.
If V1 volts is selectively supplied to terminal 10, the output of V1 option circuit 18, which may effect the operation of signal circuitry or the like (not shown) connectable to terminal 50, does not activate explosive switches 26 or 34 and the bomb is released with contacts 30, 32, 36 and 38 in the positions as shown. As hereinbefore explained, rotor 56 is activated to arm the bomb and contacts 72 are opened and contacts 54 and 70 are closed upon release of the bomb from the aircraft. At bomb impact, impact switch 52 is closed and energy storage device 22 discharges through the impact switch, closed contacts 54 and contacts 38 to activate explosive switch 58 which closes contacts 60. Energy storage device 24, which had been charged via regulator from terminal 10 at bomb release, discharges through contacts 60 and 30 into function timer 64. After a time delay TD3 provided by function timer 64, the discharge energy flows from the timer through closed contacts 70 to tire detonator 68 which initiates explosive train 92 and explode the bomb. Thus, the selection of V1 volts at terminal 10 provides a detonation option of impact plus a TDl time delay for bomb explosion.
If-Vl volts is selectably applied to terminal 10 and target detecting device 42 is mechanically initiated at linkage 46 prior to bomb release, the contacts 30, 32, 36 and 38 will stay as shown at release and contacts 72 will open and contacts 54 and 70 will close at arming. As the bomb falls and prior to impact and closure of impact switch 52, target detecting device 42, which may be a conventional proximity or VT detecting device or the like, senses the target and provides an electrical signal at lead 42. The signal is passed via contacts 54 and 38 to initiate explosive switch 58. As hereinbefore explained, closure of contacts 60 by switch 58 allows discharge of energy storage device 24 through delay timer 64. It is readily apparent, therefore, that selection of V1 volts and mechanical initiation of target detecting device 64 provides detonation of the bomb at a delay TD3 after target detection. The target detected by target detecting device 42 is normally ground. It is readily apparent, however, that the target may be any material object capable of reflecting the radiated signal from the target detecting device. Thus, a forest canopy or the like may appear as a target to target detecting device 42. By utilizing a time delay after target sensing, detonation may be provided when the bomb is some distance below the forest canopy. The distance is a function in part, of delivery speed, weapon delivery mode and the detonation delay.
If target detecting device 42 should fail to provide an electrical output signal responsive to target detection at lead 48, the bomb will continue to fall and, upon impact, close impact switch 42. The bomb then functions as if Vl volts had been selected without mechanical initiation of the target detecting device and, as hereinbefore explained, detonation occurs at impact plus TD3.
Assuming now that -V2 volts has been selectably applied to terminal 10 to activate explosive switch 26 thereby to open contacts 30 and close contact 32 prior to bomb release. Thus, function timer 66 providing a time delay TD4 is inserted in the discharge path of energy storage device 24 in lieu of function timer 64. It is readily apparent, therefore, that the bomb functions identically to that of the V1 option hereinbefore explained, the exception being that detonation will occur at impact plus TD4 rather than impact plus TD3. Similarly, mechanical initiation of target detecting device 42 in conjunction with the -V2 option provides detonation at a delay of TD4 after target detection.
The ordnance fuze also provides a detonation option wherein detonation occurs at bomb impact. Selection of +Vll volts at terminal 10 causes +V1 option circuit 14 to actuate explosive switch 34. As indicated by arrowhead 40, actuation of explosive switch 34 closes contacts 36 and opens contacts 38 prior to bomb release. After arming, which closes contacts 54 and 7 0, and upon impact, which closes impact switch 52, energy storage device 22 discharges through an energy path including the impact switch, contacts 54, contacts 36 and contacts to detonatOr 68. Thus, at impact, detonator 68 detonates explosive train 92 which results in bomb explosion.
Explosive switch 34 also may be actuated, to close contacts 36 and open contacts 38, by the selection of +V2 volts at terminal 10 and activation of option circuit 16. Activating option circuit 16 also provides an electrical signal at lead 44 to electrically initiate operation of target detecting device 42. After bomb release and subsequent arming to close contacts 54 and 70, an electrical signal at lead48 responsive to target detection will be passed via a path including contacts 54, contacts 36 and contacts 70 to actuate detonator 68 and explode the bomb at a predetermined burst height. Assuming a malfunction or the like in the target detecting device prevents an electrical output at lead 48 responsive to target detection, the bomb will continue to fall until impact. At impact, energy storage device 22 will discharge through closed impact switch 52, contacts 54, 36 and 70 to detonator 68. Thus, it is readily apparent that a backup option is provided, in case of failure of target detecting device 42, and the bomb will explode at impact as if +V1 volts rather than +V2 volts had been selected.
The various arm modes and detonation options are schematically indicated in FIG. 4. Thus, the ordnance fuze of the present invention provides a plurality of arming modes and detonation options. The detonation options are responsively selectable by direct current voltages applied while the fuze is still on the delivery vehicle. Similarly, the fuze is armed after release and is dependent on a preselected delivery mode. It is readily apparent that the times indicated are given by way of example only.
Obviously, numerous modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.
What is claimed as new and desired to be secured by Letters Patent of the United States is:
l. A selective arming mode and detonation option ordnance fuze comprising means connectable to a source of voltages of predetermined magnitudes and polarities,
means responsive to the selection of a voltage of a predetermined magnitude and polarity from said voltage source for providing electrical output signals, energy storage means, detonator means means responsive to said electrical output signals for preselecting an energy input path to said detonator means means for arming said ordnance fuze in response to the application thereto of a voltage signal of a magnitude and/or polarity indicative of a predetermined preselected delivery mode of said ordnance fuze, and
means for providing an energy input signal to said detonator means via said preselected energy input path to detonate said ordnance fuze.
2. A selective arming mode and detonation option ordnance fuze according to claim 1 wherein said means for arming said ordnance fuze further comprises rotor means switch means actuated at a predetermined time, and
means responsive to said switch means for selectively cuitry from said energy storage means to said detonator means'at fuze impact. 5. A selective arming mode and detonation option ordnance fuze according to claim 1 wherein said energy input signal providing means is a target detecting means for said energy input signal to said detonator means at target detection prior to fuze impact. 6. A selective arming mode and detonation option ordnance fuze according to claim 1 wherein said preselected energy input circuitry further includes timing means selectively insertable into said circuitry for providing predetermined time delays for detonating said ordnance fuze. 7. A selective arming mode and detonation option ordnance fuze according to claim 1 further comprising backup means for providing an energy input signal 0 said detonator to detonate said ordnance fuze if said ordnance fuze fails to detonate.