|Title of Invention||
ELECTRONIC TIME DELAY FUZE FOR HAND GRENADE AND RIFLE GRENADE
|Abstract||Electronic Time Delay circuit for initiating Mechanism comprises a power source, which is a battery, and with an electronic circuitry having micro controller, transistors, capacitors and resistors. The micro controller is precisely programmable to milli seconds to any desired time delay. The means for electrical contact between the power source and the PCB is by means of a metallic cup fixed on a spring connected to the negative terminal PCB and another metallic ring connected to the positive terminal PCB. The output of the electronic circuit is connected to means for initiation, which normally is an electric squib which can fire a detonator, flares, smoke candles etc. Incase the set time delay failed to function, the micro controller is capable of programming to any desired self-neutralization period. The PCB and associated electronic components are encased in a non-conductive container and potted by any known potting material to avoid the ingress of moisture. This initiating mechanism is actuated by un-locking the striker kept in tension by means of a spring kept away from the battery by suitable locking means. The shelf life of the system is more than 15 years, which can be increased by changing the battery once in every 7 to 8 years as it can be independently assembled.|
This invention relates to an improved method of achieving time delay for initiating mechanism for Explosives and Pyrotechnical items. Here we are making use of the electronic time delay instead of conventional chemically achievable time delay. This mechanism is having its own power source. It has got extensive use in many types of equipments where precision time actuation is required. Eg. Grenade and many other similar single shot devices.
At present the Initiating Mechanism for igniting explosive chain in use, is made of pyro technique (chemical) delay composition to obtain the desired delay for actuation of the grenade and similar devices. In this prior art system extensive usage of chemical composition is made use of, for getting delay timings and initiation. Hence the manufacturing method is cumbersome and it is difficult to get accurate time delay in terms of milli seconds. Further, it is also seen that the system is not very reliable. It has been reported that when this type of system involving chemical / pyro Initiating Mechanism and chemical delay is used; it goes blind very often or functions prematurely or often with considerable delay than specified.
Lot of safety precautions requires to be followed during the manufacture as it involves sensitive chemicals. Further incase the existing Initiating Mechanism fails to function, in systems such as Grenade; it is dangerous to handle and has to be safely demolished. The initiative mechanism based on the pyro / chemical will have a limited shelf life around three years. This causes the periodical replacement of Initiating Mechanism as the main system (Grenade, single shot devices) has got a shelf life more than fifteen years. Hence this system is not cost effective also.
Now by this invention we have come out with lasting solution. With our state of the art technology, we could over come the aforesaid difficulties being faced during the usage of existing Initiating Mechanism for time delay especially Grenades.
This initiative mechanism is actuated by any suitable means such as a striker kept under tension, which makes the contact between the terminal of the battery and the corresponding terminal of the Initiative Mechanism. Once the contact is made, the pre programmed micro controller of the Initiating Mechanism starts counting the pre-programmed time delay and gives the output pulse to the squib connected in series there by initiating the explosive chain. Normally the actuating means are locked and would be unlocked as and when required at the time of deployment.
The said initiating mechanism has got an Electronic delay circuit consists of a micro controller, transistors, capacitors, resistors, printed circuit board, power source which in turn is connected to a squib, which is electrically ignitable device having pyro composition. This system has the capability to enhance the lethality, mobility, and operational effectiveness in addition to the safety in handling.
Accordingly, the present invention consists of an electronic time delay for initiating mechanism of the explosives and pyro technique items actuatable by a striking means comprising a power source, a PCB with the electronic circuitry having micro controller, transistor, capacitors and resistors, means for making electrical contact between the power source and PCB, where in the micro controller is capable of programming to decide a time delay for actuation as well as for providing self neutralization period beyond which the whole system is inactive and safe to handle, encased in a non conductive container and potted by any known potting material to avoid the ingress of moisture, where in the output terminal of the said electronic circuit of PCB is connected to a means for initiating explosives and pyrotechnical materials which in turn is assembled with any functional means selected from detonators, flares and smoke candles.
Now the invention will be described in detail with reference to the accompanied drawing.
Figure-1 shows all the parts of an Electronic Time Delay for Initiating Mechanism of explosives and pyrotechnical items actuatable by a striking means.
3. Battery assembly,
7.Electronic circuit (PCB assembly),
Figure -2 shows block diagram of electronic time delay circuit for initiating mechanism
A programmable micro controller which can be programmed to any desired time period independent of temperature fluctuations preferably with in a range of - 60°C to +75°C. This can be actuated with a minimum voltage of 2Volts, preferably in a range of 2 to 4Volts. In a preferred embodiment, the delay time period is selected from 3 to 10 seconds. One of the state of the art features provided in this Invention is that the micro controller is programmed, such that the system goes into deactivation mode, if it fails to function after lapse of a specified self-neutralization period . viz 10seconds, 15 seconds etc. Hence in case the delay mechanism fails to function on lapse of set delay period it becomes safe to handle after the self-neutralization period. If required the faulty Initiating Mechanism can be replaced with a fresh one and the Grenade or the unit where it is used can be used once again. So there is no necessity of demolishing the unit. But in the prior art system we are supposed to demolish if it has not functioned, since it is having high explosive material.
According to our Invention the most preferred power source is a battery (3) selected from Lithium Manganese dioxide, Lithium ion, Lithium Thionyle chloride etc. which can generate a voltage above 2 Volts preferably between 2 to 4 volts. The battery can be assembled with a rubber mount inserted in a heat shrinkable sleeve, which can absorb the stored energy when the striker (1) kept in tension by means of a spring (2),when hits the battery (3). One of the novel features of the Invention is that the battery is always stored separately and is assembled only just prior to its deployment. Hence it is very safe to handle and store.
The metallic cup (4), which is negative terminal, is connected to the PCB (7) through a spring (5), which gives the negative electrical connectivity. A metallic ring (6), which is a positive terminal is also electrically connected to the PCB, enabling to complete the electrical circuit and activates the micro controller when the striker hits the battery.
In a preferred embodiment under the Invention the striker (1) and the striker spring (2) assembly is mounted in such a way that it will be under tension, away from the battery by suitable locking means. The locking means can be a locking pin suitably located.
The electrical ignition means preferably an electrical squib (9) is connected to the PCB by suitable means such as wires can function when it receives the power supply. The squib is capable of initiating the detonator (10), flare, smoke candles etc. based on end use requirement of the system.
The complete electronic circuit i.e. PCB assembly is mounted in an appropriate non-metallic container (8) and is potted by any known potting material to avoid the ingress of the moisture to the electronic circuit.
The functional details of the preferred embodiment mentioned of our invention are described in brief as under.
When the striker which is kept under tension by the striker spring of the Initiative Mechanism, when unlocked strikes the rubber mount fixed to the rear end of the battery which is in contact with the spring cup mounted on a spring, which in turn compresses the spring cup and forms the negative terminal of the battery. Simultaneously the ring connected to the PCB comes in to contact with the battery forming the positive terminal of the battery. Now the preprogrammed micro controller starts counting the delay and gives the output pulse to the squib there by initiating the explosive chain. In case it is not initiated with in the set delay period, the initiating mechanism becomes inactive and safe to handle after lapse of preset self neutralization period viz 10 seconds, 15seconds etc. This is one of the unique features of the invention, which is lacking in the prior art system.
Although the invention has been described in considerable detail with particular reference to certain preferred embodiment thereof, variations and modifications can be effected with in the spirit and scope of the invention as described herein above and as defined in the appended claims.
1. An electronic time delay for initiating mechanism of the explosives and pyrotechnique items actuatable by a striking means comprising a power source, a PCB with the electronic circuitry having micro controller, transistor, capacitors and resistors, means for making electrical contact between the power source and PCB, where in the micro controller is capable of programming to decide a time delay for actuation as well as for providing self neutralization period beyond which the whole system is inactive and safe to handle, encased in a non conductive container and potted by any known potting material to avoid the ingress of moisture, where in the output terminal of the said electronic circuit of PCB is connected to a means for initiating explosives and pyrotechnical materials which in turn is assembled with any functional means selected from detonators, flares and smoke candles.
2. Electronic time delay as claimed in claim (1) where in the power source is a battery selected from Lithium Manganese Dioxide, Lithium Ion, Lithium Thionyle chloride having voltage more than 2 volts preferably 2 to 4volts, where in the said battery is fixed with a rubber mount at the rear end and is inserted in a heat shrinkable sleeve.
3. Electronic time delay as claimed in claim (1), the micro controller is capable of programming to any desired time delay, independent of temperature variations from - 50°C to + 75°C.
4. Electronic time delay as claimed in claim (1), the micro controller is capable of programming to any desired self neutralization period in case the set time delay failed to function.
5. Electronic time delay as claimed in claim (1) the said means for making an electrical contact between the power source and the PCB comprise of a metallic cup mounted on the spring which in turn is connected to the
said negative terminal of the electronic circuit of PCB and the metallic ring connected to positive terminal of electronic circuit of PCB.
6. Electronic time delay as claimed in claim (1), the said means for initiating
explosives and pyro technique item is an electrical squib capable of
giving sufficient flame to ignite pyro composition.
7. Electronic time delay as claimed in claim (1), is capable of functioning at
extreme temperatures selected from - 60°C to +75°C most preferably
from - 40°C to +65°C.
8. Electronic time delay as claimed in claim (1), is capable of giving a
storage life of more than 15 years, wherein power source is replaced
once every 7 or 8 years.
9. Electronic time delay as claimed in claim (1), the means for power
source and the rest of assembly is independent and capable of storing
separately and independently loadable ensuring the safety of the
10. Electronic time delay for initiating mechanism of explosive / pyro
technique items substantially here in described with reference to and
illustrated in figure 1 and 2 of the accompanying drawings.
|Indian Patent Application Number||813/CHE/2007|
|PG Journal Number||26/2012|
|Date of Filing||17-Apr-2007|
|Name of Patentee||HBL POWER SYSTEMS LTD|
|Applicant Address||8-2-601, ROAD NO:10, BANJARA HILLS ,HYDERABAD-500 034|
|PCT International Classification Number||E21B29/02|
|PCT International Application Number||N/A|
|PCT International Filing date|