Title of Invention	"A FLEXIBLE REINFORCED EXPLOSIVE TRANSFER LINE AND A PROCESS FOR PREPARATION THEREOF"
Abstract	This invention relates to a flexible reinforced explosive transfer line capable of transmitting shock from one point to another without affecting the surroundings comprising miniature detonating cord (1) of a lead alloy tube containing explosive characterised in that is the said tube is braided with multiple layers of resin and fibre glass yarn to strengthen and increase outer diameter of the tube, a nylon sleeve (4) having the braided miniature detonating cord (MDC) (5) disposed therein, said nylon sleeve being braided with SS wire, a connector rod (6) over said consolidated miniature detonating cord (MDC) and held in position with an adhesive (11), a booster cup (7) containing loose booster explosive (10). Further according to this invention a process for preparation of flexible reinforced explosive transfer line comprising in the steps of preparing a miniature detonating cord (MDC), consolidating over the MDC a resin with fiber glass yarn braiding followed by braiding with fiber glass yarn on the said cured and consolidated MDC, inserting the fiber glass yarn braided MDC into a nylon sleeve which is then braided with SS wire, assembling the consolidated MDC and booster cup through connector rod by inserting one end of connector rod over MDC and other end into the booster cup followed by crimping of booster cup over the connector rod.

Title of Invention

"A FLEXIBLE REINFORCED EXPLOSIVE TRANSFER LINE AND A PROCESS FOR PREPARATION THEREOF"

Abstract

This invention relates to a flexible reinforced explosive transfer line capable of transmitting shock from one point to another without affecting the surroundings comprising miniature detonating cord (1) of a lead alloy tube containing explosive characterised in that is the said tube is braided with multiple layers of resin and fibre glass yarn to strengthen and increase outer diameter of the tube, a nylon sleeve (4) having the braided miniature detonating cord (MDC) (5) disposed therein, said nylon sleeve being braided with SS wire, a connector rod (6) over said consolidated miniature detonating cord (MDC) and held in position with an adhesive (11), a booster cup (7) containing loose booster explosive (10). Further according to this invention a process for preparation of flexible reinforced explosive transfer line comprising in the steps of preparing a miniature detonating cord (MDC), consolidating over the MDC a resin with fiber glass yarn braiding followed by braiding with fiber glass yarn on the said cured and consolidated MDC, inserting the fiber glass yarn braided MDC into a nylon sleeve which is then braided with SS wire, assembling the consolidated MDC and booster cup through connector rod by inserting one end of connector rod over MDC and other end into the booster cup followed by crimping of booster cup over the connector rod.

Full Text	FIELD OF INVENTION: explosive transfer line This invention relates to a flexible reinforced/and a process for preparation thereof. The flexible reinforced explosive transfer lines are used for canopy severance in emergency escape system of fighter air crafts, missiles and other aerospace applications. PRIOR ART: A one-way explosive transfer assembly as per US Patent No.3,326,127 involves an explosive connector device with internal angled bores, each containing an out of line explosive device. The devices are initiated by sharpnel charge produced by fragmentation of a component. Another one-way explosive transfer assembly as per US Patent No.3,460,477 involves a fixed wall separating the acceptor charge and donor charge which are in opposite bores. Still another one-way explosive transfer assembly as per US Patent No.4,423,682 involves a mild detonating cord end tip which actuates a firing pin to initiate a primer which in turn initiates a standard explosive train to detonate the output shielded mild detonating cord. The cited patents have drawbacks of either indirect initiation modes or moving components, which are overcome in the present invention. OBJECTS OF THE INVENTION: The main object of the present invention is to provide a flexible reinforced explosive transfer line and process for preparation thereof, where-in explosive transfer line obtained by the process enables transmission of explosive shock along the length in either direction, without affecting the surroundings. Another object of the present invention is to provide a flexible reinforced explosive transfer line which incorporates a miniature detonating cord having a low explosive loading in the range of 0.3 to 0.6g/m which when initiated is withstood by the reinforcement provided to the miniature detonating cord. DESCRIPTION OF INVENTION According to this invention there is provided a flexible reinforced explosive transfer line capable of transmitting shock from one point to another without affecting the surroundings comprising:- a) miniature detonating cord of a lead alloy tube containing explosive characterised in that is the said tube is braided with multiple layers of resin and fibre glass yarn to strengthen and increase outer diameter of the tube b) a nylon sleeve having the braided miniature detonating cord (MDC) disposed therein, said nylon sleeve being braided with SS wire c) a connector rod over said consolidated miniature detonating cord (MDC) and held in position with an adhesive d) a booster cup containing loose booster explosive. Further, according to this invention there is provided a process for preparation of flexible reinforced explosive transfer line comprising in the steps of:- (a) preparing a miniature detonating cord (MDC), (b) consolidating over the MDC a resin with fiber glass yarn braiding followed by braiding with fiber glass yarn on the said cured and consolidated MDC (c) inserting the fiber glass yarn braided MDC into a nylon sleeve which is then braided with SS wire (d) assembling the consolidated MDC and booster cup through connector rod by inserting one end of connector rod over MDC and other end into the booster cup followed by crimping of booster cup over the connector rod. DESCRIPTION OF FIGURES: The present invention is illustrated with accompanying drawings which are intended to illustrate an embodiment of the present invention, wherein: Fig. 1.- shows the vertical section of flexible reinforced explosive transfer line. Fig. 1(a)- shows the cross-section of the flexible reinforced miniature detonating cord. fiber glass yarn is done on the MDC. Three such coatings and braidings are done in succession. Finally, a resin coating is given to the said coated MDC. The uniformity of the cord is ensured by passing the complete cord through a suitable gauge. After curing of resin at room temperature for 42 to 48 hours, a consolidated MDC is attained, over which a final braiding of three layers with fiber glass yarn is done to obtain the desired outer diameter of the cord. The said fiber glass braided MDC is inserted into a nylon sleeve which is further braided with a layer of stainless steel wire. The braiding of stainless steel wire and fibre glass yarn along with the nylon sleeve are removed from the surface to expose the consolidated MDC, for about 20 to 30mm in length from both the ends. The connector rods are inserted over this MDC, from both the ends, and held in position with an adhesive like cyanocrylate. The open space between the face of the connector rod and reinforcement of MDC if any, is filled with araldite. The terminals of the said MDC are cut such that they are projecting about 2mm above the other face of connector rod at both the ends. Each end of said MDC is inserted into the filled booster cup, touching the said booster compositions based on PETN or RDX and the excess empty portion is crimped over the connector rod. Each end of assembly is housed in a stainless steel body and the body is crimped on the braided portion. FRETL of the present invention can be flexed up to 10,000 cylces without breaking and bent into a circular radius of 80 mm without undergoing any damage to the continuity of explosive stock transmission. FRETL functions reliability under adverse thermal and environment conditions. The FRETL can reliably transmit explosive block up to 12m length. The output end of the flexible reinforced explosive transfer line is secured on to the male threads of junction box with the female threads of the cap sliding over the reinforced MDC. DESCRIPTION OF FIGURES: The present invention is illustrated with accompanying drawings which are intended to illustrate an embodiment of the present invention, where-in: Fig 1. - Shows the vertical section of flexible reinforced explosive transfer line Fig 1(a):- shows the cross-section of the flexible reinforced miniature detonating cord Fig 1(b):- shows the enlarged view of the terminal end assembly of FRETL Fig 2 - shows the assembly of FRETL with the junction box. DESCRIPTION OF EXPLOSIVE TRANSFER LINE W.R.T. DRAWINGS: The vertical section of flexible reinforced explosive transfer line (FRETL) at Fig 1(a) illustrates the details of braided MDC of the present invention which incorporates a Miniature Detonating Cord (MDTJ) (1) which is a lead alloy tube of size 1.6 to 1.7 mm outer diameter, about 0.6 to 0.7 mm internal diameter. The uniformity of the tube is ensured by passing the MDC through a suitable gauge. The MDC (1) is coated with a resin over which is braided with fibre glass yarn thrice. A final coat of resin is applied to attain finished MDC of the required diameter and allowed to cure to attain a consolidated MDC (2). Further the said MDC (2) is braided thrice with a fiber glass yarn to attain a fiber glass braided MDC(3) and is inserted into a Nylon sleeve (4) of suitable thickness and diameter. One layer of SS wire is braided over the Nylon sleeve (4). The final diameter of the steel braided MDC (5) from both ends. A gap if any between the face of the connector rod (6) and shield of the said MDC (5) is filled with araldite (11). The tip of MDC (2) is cut such that it is about 2mm above the surface of the connector rod (6). The tip of MDC is inserted into a booster cup (7) containing about 70 mg of loose booster explosive (10) and crimped over connector. The above said assembly, containing connector rod (6) and booster cup (7) at both the ends is housed in a stainless steel body (8) is crimped on the braided portion. A stainless steel cap (9) is sliding over the stainless steel braided MDC (5) for securing the terminal end of FRETL to the junction box. Fig 2 shows the explosive filled Aluminium cup (12) in contact with booster cup (7) and protruding male thread portion (13) of the junction box over which female threads of the cap (9) are fastened. A protective cover (14) protects the booster cup and female threads of the cap during transit and storage. PREPARATION OF FLEXIBLE REINFORCED EXPLOSIVE TRANSFER LINE (FRETL) : The process of preparation comprises of following three steps:- a) Preparation of Miniature Detonating Cord (MDC): A lead alloy tube of size 7.0 to 10.0 mm outer diameter (OD) and 3.0 to 5.0 mm inner diameter (ID) is cut into a length of about 60 cm. Gauges of suitable diameter are passed through the ID to ensure uniformity. The tube is sealed by crimping from one end and is weighed on a balance with 0.5 g accuracy. The tube is filled with the explosive using a brass funnel in installments of approximately lg each. After addition of each installment of the explosive, the closed end of the tube is tapped for two minutes slowly on a table to ensure uniformity. The tube is filled uniformly leaving about 5mm from the filling end and is later sealed by crimping. The said filled tube is weighed to the nearest 0.5 g'. The lead tube thus prepared is passed successively through truncated grooves of reduced areas of a roller to obtain outer diameter of 3-4 mm. The truncated cord is then drawn through a set of dies on a drawing bench to attain a circular cord of 1.6 to 1.7 mm OD. During this process there is a corresponding increase in the length of the tube. The total length of the tube is 12.0 to 12.5 m called the miniature detonating cord (MDC) (1) The loading density in g/m of MDC is determined by chemical method. The continuity in the explosive filling is confirmed by non-destructive test methods like Neutron radiography or X-ray radiography. b) Braiding : MDC (1) is passed through a tray containing room temperature curing resin and fed into the braiding machine loaded with the fibre glass yarn. The braiding is done over the wet resin, thus consolidating over the MDC. This procedure is repeated thrice. A final coat of resin is given on the above said MDC to attain the required diameter. The consolidated MDC (2) is passed through a suitable gauge to maintain uniform outer diameter (OD) and the resin is allowed to cure at room temperature for 42 to 48 hours. After complete curing of resin, three layers of fiber glass yarn braiding is further continued to end up with the required final OD as per design requirements. The braided MDC (3) is inserted into a nylon sleeve (4) of suitable diameter and thickness. One layer of SS wire is braided over the nylon sleeve (4) to get a braided MDC with 8 to 10 mm final OD. The steel braided MDC (5) is assembled with end connectors. c) Assembly of End Connectors for FRETL The shields of braided MDC (5) are removed from both ends for about 20 to 30 mm in length as per requirement till the consolidated MDC(2) is exposed. The connector rod (6) is inserted over this consolidated MDC (2) and fixed in position with cyanoacrylate adhesive. About 70 mg of loose booster explosive is filled into the booster cup (7). The tip of consolidated MDC (2) is cut such that it projects about 2mm above the tip of connector rod (6). Araldite (11) is applied on to the gap, if any, between the reinforcement and the face of connector rod. The body (8) is crimped on the steel braided portion of the said MDC (5), A stainless steel cap (9) is slid over the stainless steel braided MDC (5) for securing the terminal end of FRETL to the junction box. An Aluminium cup (12) of dimension 4.0 mm diameter and length 10 mm containing about 115 mg RDX based composition is assembled in the junction box. The junction box contains four protruding male thread portions (13) over which female threads of the cap (9) are fastened. PERFORMANCE CHARACTERISTICS OF FRETL: The FRETLs thus prepared were connected to the initiating system or any intermediate system and observed for their performance. In the very large number of firings conducted, the transfer of detonation was complete from one end to another and over junction boxes through a network and no damage was observed to the covering as well as the suiTOundings. The functioning of the FRETLs was not adversely affected by the different environmental conditions like temperature ranges, -65°C to 90°C, 100% humidity, free fall rain, salt, mist etc. and were found to give full performance in all conditions. The FRETLs were tested upon a length of 12 metres and found to reliably transfer the detonation. To test the performance of these FRETLs under adverse mechanical conditions, they were flexed up to 12,000 cycles through different circular radii 80 mm. In all the trials, it was observed that the shock is transmitted over the entire length of the FRETL and the outer coverings were not damaged thus ensuring that the shock is confined with the braiding. It is to be understood that the process of the present invention is susceptible to modifications, changes and adaptations by those skilled in the art. Such modifications, changes, adaptations are intended to be within the scope of the present invention which is further set forth under the following claims:- WE CLAIM; 1. A flexible reinforced explosive transfer line capable of transmitting shock from one point to another without affecting the surroundings comprising: - a) miniature detonating cord (1) of a lead alloy tube containing explosive characterised in that is the said tube is braided with multiple layers of resin and fibre glass yarn to strengthen and increase outer diameter of the tube, b) a nylon sleeve (4) having the braided miniature detonating cord (MDC) (5) disposed therein, said nylon sleeve being braided with SS wire, c) a connector rod (6) over said consolidated miniature detonating cord (MDC) and held in position with an adhesive (11), d) a booster cup (7) containing loose booster explosive (10). 2. A flexible reinforced explosive transfer line as claimed in claim 1 wherein the outer diameter of the said lead alloy tube of said MDC (1) is preferably about 1.6 to 1.7 mm dia. 3. A flexible reinforced explosive transfer line as claimed in claim 1 wherein inner dia of the said lead alloy tube of said MDC (1) is preferably 0.6 to 1.0 mm. 4. A flexible reinforced explosive transfer line as claimed in claim 1 wherein the tip of MDC has a cut so that it is preferably 2mm above the tip of connector rod (6). 5. A flexible reinforced explosive transfer line as claimed in claim 1 wherein explosive filled in said MDC is selected from HNX, RDX, HNS or PETN in fine powdered form. 6. A flexible reinforced explosive transfer line as claimed in claim 1 wherein gap if any between shield and face of connector (6) is filled with an adhesive like araldite (11). 7. A line process for preparation of flexible reinforced explosive transfer line as claimed in claim 1 comprising in the steps of: - (a) preparing a miniature detonating cord (MDC), (b) consolidating over the MDC a resin with fiber glass yarn braiding followed by braiding with fiber glass yarn on the said cured and consolidated MDC, (c) inserting the fiber glass yarn braided MDC into a nylon sleeve which is then braided with SS wire, (d) assembling the consolidated MDC and booster cup through connector rod by inserting one end of connector rod over MDC and other end into the booster cup followed by crimping of booster cup over the connector rod. 8. A process as claimed in claim 8 wherein said preparation of MDC involves filling lead tube with explosive through open end and sealed. 9. A process as claimed in claim 8 wherein outer dia of lead tube is reduced from 7 to 10 mm to 1.6 mm to 1.7 mm by passing successively through truncated grooves of reducing areas of roller followed by passing through a set of dies. 10. A process as claimed in claim 8 wherein said braiding of said miniature detonating cord involves: - a) Coating miniature detonating cord with room temperature curing resin and the said MDC with wet resin into the braiding machine loaded with fibre glass yarn. Repeating this process three times followed by final coating of resin and curing at room temperature for 42 to 48 hours, b) Braiding the consolidated MDC with fibre glass yarn and inserting into a nylon tube, c) Braiding the nylon tube with stainless steel wire. 11. A process as claimed in claim 11 wherein connector rod over MDC is held in position by an adhesive like cyanoacrylate. 12. A process for the preparation of a flexible reinforced explosive transfer line substantially as herein described and illustrated. 13. A flexible reinforced explosive transfer line substantially as described and illustrated herein.

Full Text

FIELD OF INVENTION:
explosive transfer line This invention relates to a flexible reinforced/and a process for preparation thereof. The flexible reinforced explosive transfer lines are used for canopy severance in emergency escape system of fighter air crafts, missiles and other aerospace applications.
PRIOR ART:
A one-way explosive transfer assembly as per US Patent No.3,326,127 involves an explosive connector device with internal angled bores, each containing an out of line explosive device. The devices are initiated by sharpnel charge produced by fragmentation of a component.
Another one-way explosive transfer assembly as per US Patent No.3,460,477 involves a fixed wall separating the acceptor charge and donor charge which are in opposite bores.
Still another one-way explosive transfer assembly as per US Patent No.4,423,682 involves a mild detonating cord end tip which actuates a firing pin to initiate a primer which in turn initiates a standard explosive train to detonate the output shielded mild detonating cord.
The cited patents have drawbacks of either indirect initiation modes or moving components, which are overcome in the present invention.
OBJECTS OF THE INVENTION:
The main object of the present invention is to provide a flexible reinforced explosive transfer line and process for preparation thereof, where-in explosive transfer line obtained by the process enables transmission of explosive shock along the length in either direction, without affecting the surroundings.
Another object of the present invention is to provide a flexible reinforced explosive transfer line which incorporates a miniature detonating cord having a low explosive loading in the range of 0.3 to 0.6g/m which when initiated is withstood by the reinforcement provided to the miniature detonating cord.

DESCRIPTION OF INVENTION
According to this invention there is provided a flexible reinforced explosive transfer line capable of transmitting shock from one point to another without affecting the surroundings comprising:-
a) miniature detonating cord of a lead alloy tube containing explosive characterised in that is the said tube is braided with multiple layers of resin and fibre glass yarn to strengthen and increase outer diameter of the tube
b) a nylon sleeve having the braided miniature detonating cord (MDC) disposed therein, said nylon sleeve being braided with SS wire
c) a connector rod over said consolidated miniature detonating cord (MDC) and held in position with an adhesive
d) a booster cup containing loose booster explosive.
Further, according to this invention there is provided a process for preparation of flexible reinforced explosive transfer line comprising in the steps of:-
(a) preparing a miniature detonating cord (MDC),
(b) consolidating over the MDC a resin with fiber glass yarn braiding followed by braiding with fiber glass yarn on the said cured and consolidated MDC
(c) inserting the fiber glass yarn braided MDC into a nylon sleeve which is then braided with SS wire
(d) assembling the consolidated MDC and booster cup through connector rod by inserting one end of connector rod over MDC and other end into the booster cup followed by crimping of booster cup over the connector rod.
DESCRIPTION OF FIGURES:
The present invention is illustrated with accompanying drawings which are intended to illustrate an embodiment of the present invention, wherein:
Fig. 1.- shows the vertical section of flexible reinforced explosive transfer
line.
Fig. 1(a)- shows the cross-section of the flexible reinforced miniature
detonating cord.

fiber glass yarn is done on the MDC. Three such coatings and braidings are done in succession. Finally, a resin coating is given to the said coated MDC. The uniformity of the cord is ensured by passing the complete cord through a suitable gauge. After curing of resin at room temperature for 42 to 48 hours, a consolidated MDC is attained, over which a final braiding of three layers with fiber glass yarn is done to obtain the desired outer diameter of the cord. The said fiber glass braided MDC is inserted into a nylon sleeve which is further braided with a layer of stainless steel wire.
The braiding of stainless steel wire and fibre glass yarn along with the nylon sleeve are removed from the surface to expose the consolidated MDC, for about 20 to 30mm in length from both the ends. The connector rods are inserted over this MDC, from both the ends, and held in position with an adhesive like cyanocrylate. The open space between the face of the connector rod and reinforcement of MDC if any, is filled with araldite. The terminals of the said MDC are cut such that they are projecting about 2mm above the other face of connector rod at both the ends. Each end of said MDC is inserted into the filled booster cup, touching the said booster compositions based on PETN or RDX and the excess empty portion is crimped over the connector rod. Each end of assembly is housed in a stainless steel body and the body is crimped on the braided portion. FRETL of the present invention can be flexed up to 10,000 cylces without breaking and bent into a circular radius of 80 mm without undergoing any damage to the continuity of explosive stock transmission. FRETL functions reliability under adverse thermal and environment conditions. The FRETL can reliably transmit explosive block up to 12m length.
The output end of the flexible reinforced explosive transfer line is secured on to the male threads of junction box with the female threads of the cap sliding over the reinforced MDC.
DESCRIPTION OF FIGURES:
The present invention is illustrated with accompanying drawings which are intended to illustrate an embodiment of the present invention, where-in:
Fig 1. - Shows the vertical section of flexible reinforced explosive
transfer line Fig 1(a):- shows the cross-section of the flexible reinforced
miniature detonating cord

Fig 1(b):- shows the enlarged view of the terminal end assembly of
FRETL Fig 2 - shows the assembly of FRETL with the junction box.
DESCRIPTION OF EXPLOSIVE TRANSFER LINE W.R.T. DRAWINGS:
The vertical section of flexible reinforced explosive transfer line (FRETL) at Fig 1(a) illustrates the details of braided MDC of the present invention which incorporates a Miniature Detonating Cord (MDTJ) (1) which is a lead alloy tube of size 1.6 to 1.7 mm outer diameter, about 0.6 to 0.7 mm internal diameter. The uniformity of the tube is ensured by passing the MDC through a suitable gauge. The MDC (1) is coated with a resin over which is braided with fibre glass yarn thrice. A final coat of resin is applied to attain finished MDC of the required diameter and allowed to cure to attain a consolidated MDC (2). Further the said MDC (2) is braided thrice with a fiber glass yarn to attain a fiber glass braided MDC(3) and is inserted into a Nylon sleeve (4) of suitable thickness and diameter. One layer of SS wire is braided over the Nylon sleeve (4). The final diameter of the steel braided MDC (5) from both ends. A gap if any between the face of the connector rod (6) and shield of the said MDC (5) is filled with araldite (11). The tip of MDC (2) is cut such that it is about 2mm above the surface of the connector rod (6). The tip of MDC is inserted into a booster cup (7) containing about 70 mg of loose booster explosive (10) and crimped over connector. The above said assembly, containing connector rod (6) and booster cup (7) at both the ends is housed in a stainless steel body (8) is crimped on the braided portion. A stainless steel cap (9) is sliding over the stainless steel braided MDC (5) for securing the terminal end of FRETL to the junction box. Fig 2 shows the explosive filled Aluminium cup (12) in contact with booster cup (7) and protruding male thread portion (13) of the junction box over which female threads of the cap (9) are fastened. A protective cover (14) protects the booster cup and female threads of the cap during transit and storage.
PREPARATION OF FLEXIBLE REINFORCED EXPLOSIVE TRANSFER LINE (FRETL) :
The process of preparation comprises of following three steps:-

a) Preparation of Miniature Detonating Cord (MDC):
A lead alloy tube of size 7.0 to 10.0 mm outer diameter (OD) and 3.0 to 5.0 mm inner diameter (ID) is cut into a length of about 60 cm. Gauges of suitable diameter are passed through the ID to ensure uniformity. The tube is sealed by crimping from one end and is weighed on a balance with 0.5 g accuracy. The tube is filled with the explosive using a brass funnel in installments of approximately lg each. After addition of each installment of the explosive, the closed end of the tube is tapped for two minutes slowly on a table to ensure uniformity. The tube is filled uniformly leaving about 5mm from the filling end and is later sealed by crimping. The said filled tube is weighed to the nearest 0.5 g'. The lead tube thus prepared is passed successively through truncated grooves of reduced areas of a roller to obtain outer diameter of 3-4 mm. The truncated cord is then drawn through a set of dies on a drawing bench to attain a circular cord of 1.6 to 1.7 mm OD. During this process there is a corresponding increase in the length of the tube. The total length of the tube is 12.0 to 12.5 m called the miniature detonating cord (MDC) (1) The loading density in g/m of MDC is determined by chemical method. The continuity in the explosive filling is confirmed by non-destructive test methods like Neutron radiography or X-ray radiography.
b) Braiding :
MDC (1) is passed through a tray containing room temperature curing resin and fed into the braiding machine loaded with the fibre glass yarn. The braiding is done over the wet resin, thus consolidating over the MDC. This procedure is repeated thrice. A final coat of resin is given on the above said MDC to attain the required diameter. The consolidated MDC (2) is passed through a suitable gauge to maintain uniform outer diameter (OD) and the resin is allowed to cure at room temperature for 42 to 48 hours. After complete curing of resin, three layers of fiber glass yarn braiding is further continued to end up with the required final OD as per design requirements. The braided MDC (3) is inserted into a nylon sleeve (4) of suitable diameter and thickness. One layer of SS wire is braided over the nylon sleeve (4) to get a braided MDC with 8 to 10 mm final OD. The steel braided MDC (5) is assembled with end connectors.

c) Assembly of End Connectors for FRETL
The shields of braided MDC (5) are removed from both ends for about 20 to 30 mm in length as per requirement till the consolidated MDC(2) is exposed. The connector rod (6) is inserted over this consolidated MDC (2) and fixed in position with cyanoacrylate adhesive. About 70 mg of loose booster explosive is filled into the booster cup (7). The tip of consolidated MDC (2) is cut such that it projects about 2mm above the tip of connector rod (6). Araldite (11) is applied on to the gap, if any, between the reinforcement and the face of connector rod. The body (8) is crimped on the steel braided portion of the said MDC (5), A stainless steel cap (9) is slid over the stainless steel braided MDC (5) for securing the terminal end of FRETL to the junction box. An Aluminium cup (12) of dimension 4.0 mm diameter and length 10 mm containing about 115 mg RDX based composition is assembled in the junction box. The junction box contains four protruding male thread portions (13) over which female threads of the cap (9) are fastened.
PERFORMANCE CHARACTERISTICS OF FRETL:
The FRETLs thus prepared were connected to the initiating system or any intermediate system and observed for their performance. In the very large number of firings conducted, the transfer of detonation was complete from one end to another and over junction boxes through a network and no damage was observed to the covering as well as the suiTOundings. The functioning of the FRETLs was not adversely affected by the different environmental conditions like temperature ranges, -65°C to 90°C, 100% humidity, free fall rain, salt, mist etc. and were found to give full performance in all conditions. The FRETLs were tested upon a length of 12 metres and found to reliably transfer the detonation. To test the performance of these FRETLs under adverse mechanical conditions, they were flexed up to 12,000 cycles through different circular radii 80 mm. In all the trials, it was observed that the shock is transmitted over the entire length of the FRETL and the outer coverings were not damaged thus ensuring that the shock is confined with the braiding.
It is to be understood that the process of the present invention is susceptible to modifications, changes and adaptations by those skilled in the art. Such modifications, changes, adaptations are intended to be within the scope of the present invention which is further set forth under the following claims:-

WE CLAIM;
1. A flexible reinforced explosive transfer line capable of transmitting shock from one point to another without affecting the surroundings comprising: -
a) miniature detonating cord (1) of a lead alloy tube containing explosive characterised in that is the said tube is braided with multiple layers of resin and fibre glass yarn to strengthen and increase outer diameter of the tube,
b) a nylon sleeve (4) having the braided miniature detonating cord (MDC) (5) disposed therein, said nylon sleeve being braided with SS wire,
c) a connector rod (6) over said consolidated miniature detonating cord (MDC) and held in position with an adhesive
(11),
d) a booster cup (7) containing loose booster explosive (10).
2. A flexible reinforced explosive transfer line as claimed in claim 1 wherein the outer diameter of the said lead alloy tube of said MDC (1) is preferably about 1.6 to 1.7 mm dia.
3. A flexible reinforced explosive transfer line as claimed in claim 1 wherein inner dia of the said lead alloy tube of said MDC (1) is preferably 0.6 to 1.0 mm.
4. A flexible reinforced explosive transfer line as claimed in claim 1 wherein the tip of MDC has a cut so that it is preferably 2mm above the tip of connector rod (6).

5. A flexible reinforced explosive transfer line as claimed in claim 1
wherein explosive filled in said MDC is selected from HNX, RDX,
HNS or PETN in fine powdered form.
6. A flexible reinforced explosive transfer line as claimed in claim 1
wherein gap if any between shield and face of connector (6) is filled
with an adhesive like araldite (11).
7. A line process for preparation of flexible reinforced explosive transfer line as claimed in claim 1 comprising in the steps of: -
(a) preparing a miniature detonating cord (MDC),
(b) consolidating over the MDC a resin with fiber glass
yarn braiding followed by braiding with fiber glass
yarn on the said cured and consolidated MDC,
(c) inserting the fiber glass yarn braided MDC into a
nylon sleeve which is then braided with SS wire,
(d) assembling the consolidated MDC and booster cup
through connector rod by inserting one end of
connector rod over MDC and other end into the
booster cup followed by crimping of booster cup over
the connector rod.
8. A process as claimed in claim 8 wherein said preparation of MDC involves filling lead tube with explosive through open end and sealed.

9. A process as claimed in claim 8 wherein outer dia of lead tube is
reduced from 7 to 10 mm to 1.6 mm to 1.7 mm by passing
successively through truncated grooves of reducing areas of roller
followed by passing through a set of dies.
10. A process as claimed in claim 8 wherein said braiding of said
miniature detonating cord involves: -
a) Coating miniature detonating cord with room temperature curing resin and the said MDC with wet resin into the braiding machine loaded with fibre glass yarn. Repeating this process three times followed by final coating of resin and curing at room temperature for 42 to 48 hours,
b) Braiding the consolidated MDC with fibre glass yarn and inserting into a nylon tube,
c) Braiding the nylon tube with stainless steel wire.

11. A process as claimed in claim 11 wherein connector rod over MDC is held in position by an adhesive like cyanoacrylate.
12. A process for the preparation of a flexible reinforced explosive transfer line substantially as herein described and illustrated.

13. A flexible reinforced explosive transfer line substantially as
described and illustrated herein.

Documents:

251-del-2002-abstract-(14-09-2007).pdf

251-del-2002-claims-(14-09-2007).pdf

251-DEL-2002-Claims-25-08-2008.pdf

251-del-2002-claims-correspondence-others-(14-09-2007).pdf

251-del-2002-description (complete)-(14-09-2007).pdf

251-DEL-2002-Description (Complete)25-08-2008.pdf

251-del-2002-drawings.pdf

251-del-2002-form-3.pdf

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Patent Number

222858

Indian Patent Application Number

251/DEL/2002

PG Journal Number

44/2008

Publication Date

31-Oct-2008

Grant Date

26-Aug-2008

Date of Filing

19-Mar-2002

Name of Patentee

ADDITIONAL DIRECTOR (IPR)

Applicant Address

DEFENCE RESEARCH & DEVELOPMENT ORGANISATION MINISTRY OF DEFENCE, GOVT. OF INDIA. B-341, SENA BHAWAN, DHQ P.O NEW DELHI-110011

Inventors:

#	Inventor's Name	Inventor's Address
1	KONDEPUDI UDAYA BHASKER RAO	HIGH ENERGY MATERIALS RESEARCH LABORATORY, ARMAMENT POST, PUNE 411 021.
2	JAYANT MORESHWAR SANE	HIGH ENERGY MATERIALS RESEARCH LABORATORY, ARMAMENT POST, PUNE 411 021.
3	KOTHANDARAMAN KRITHIKAVASAN	HIGH ENERGY MATERIALS RESEARCH LABORATORY, ARMAMENT POST, PUNE 411 021.
4	CHANDRAKANT NARAYAN GHAVATE	HIGH ENERGY MATERIALS RESEARCH LABORATORY, ARMAMENT POST, PUNE 411 021.

PCT International Classification Number

F42B 15/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA