US3724318A

US3724318A - Process for the production of a fuse having a hollow channel

Info

Publication number: US3724318A
Application number: US00094842A
Authority: US
Inventors: W Rohde; W Helfgen
Original assignee: Dynamit Nobel AG
Current assignee: Dynamit Nobel AG
Priority date: 1969-12-03
Filing date: 1970-12-03
Publication date: 1973-04-03
Anticipated expiration: 1990-04-03
Also published as: FR2072800A5; SE381865B; GB1328388A; CH527138A; NO124533B; BE759755A; DE1960569A1; CA953547A; ZA708068B; DE1960569B2; DE1960569C3

Abstract

Process and apparatus for the production of a fuse having a cavity extending axially within the explosive core and being provided with a lining. The process includes the steps of continuously producing a casing at the lower end of the feed hopper, introducing an explosive from the feed hopper into the casing, passing the lining through the feed hopper while continuously winding filaments therearound in a helical manner for centrally guiding the lining through the feed hopper, and continuously introducing the lining together with the explosive into the casing at the end of the feed hopper. The apparatus includes a draw-off mechanism arranged vertically above the feed hopper, and one or more supply bobbins for the filaments can be provided as well as a bobbin for a tracer thread.

Description

Ellie 1* States Patent [I91 1 3,7 24,318 Rohde et al. 451 Apr. 3, 1973 [541 PROCESS FOR THE PRODUCTION OF 1,023,142 4 1912 Ellsworth ..'.'.:......86/22 A FUSE. HAVING A HOLLOW CHANNEL Primary Examiner-Ben'amin A. Borchelt A 'E H J ldT d I v ssistant xamineraro u or [75] Inventors m ig gggg} 3:22;) Heltgen Att0meyCraig, Antonelli, Stewart & Hill [73] Assignee: Dynamit Nobel Aktiengesellschaft,- [57] ABSTRACT Trolsdorfc'ermany Process and apparatus for the production of a fuse [22] Filed: Dec.'3, 1970- having a cavity extending axially within the explosive core and being provided with a lining. The process in- [21] Appl 94842 eludes the steps of continuously producing a casing at I the lower end of the feed hopper, introducing an ex- [30] Foreign Application Priority Data plosive from the feed hopper into the casing, passing the lining through the feed hopper while continuously Dec. 3, 1969 Germany ..P i9 60 569.7 winding filaments therearound in a helical manner for centrally guiding the lining through the feed hopper, lll and continuously introducing the lining together h [58] Fieid 57/7 8 the explosive into the casing at the end of the feed hopper. The apparatus includes a draw-off mechanism arranged vertically above the feed hopper, and one or [56] References cued more supply bobbins for the filaments can be provided UNITED STATES PATENTS as well as a bobbin for a tracer thread.

3,381,568 5/1968 Kelly et al ..86/1 R 15 Claims, 2 Drawing Figures PATENTEDAPR 3 I973 SHEET 1 BF 2 INVENTORS WILHELM ROHDE WERNER HELFGEN BY o a ANLQL ATTORNEYS PROCESS FOR THE PRODUCTION OF A FUSE HAVING A HOLLOW CHANNEL BACKGROUND OF THE INVENTION The present invention relates to a process and apparatus for the production of a fuse having a cavity extending axially within the explosive core and being provided with a lining.

As is known, fuses serve for the transmission of detonations to farther remote detonable systems. These fuses usually have a continuous explosive core in a casing, the so-called sheath, for transmitting the initiating impulse, wherein a corresponding propagation velocity of the initiating impulse results depending on the type of explosive employed and the compression thereof.

It has now been found that the detonation velocity of a fuse having a cavity which extends within the explosive core over the entire axial length of the fuse and which is provided with a lining, e.g., a hose, a tube, or the like, is substantially increased.

SUMMARY OF THE INVENTION It is the object of the present invention to provide an economical process by means of which an axially extending cavity can be incorporated into a fuse. In this connection, the present invention starts with a continuous process for the production of fuses wherein the explosive is introduced from a feeding hopper into a casing which is continuously manufactured at the lower end of the hopper.

In accordance with the present invention, the lining forming the hollow space is guided through the feeding hopper and is continuously introduced, together with the explosive, into the casing at the end of the feeding hopper. The continuous axial cavity created in this manner within the explosive core results, depending on the conditions, in a more or less strong increase in the detonation velocity of the thus-manufactured fuse.

For the quality of the fuse to be produced, the position assumed by the lining such as, for example, a thermoplastic synthetic hose of polyethylene, within the explosive core is important. Optimum increases in the detonation velocity of the fuse are obtained in case the lining is disposed centrally within the explosive core. Any deviation from the center of the explosive core, any change in the cross-sectional shape, e.g., by indenting the wall, impair the desired increase in detonation velocity to a greater or lesser extent. Therefore, according to a further feature of the process of the present invention, it is suggested to wind two or more filaments helically about the lining to surround the lining in the manner of windings, and to guide the lining by means of the filaments centrally through the feeding hopper. Thus, the position of the lining, e.g., a tube, is fixed and centered in the explosive core by means of the filaments; besides, the filaments prevent any undesired indentations in the tube wall and deformations, which can occur in unfavorable instances.

According to a further feature of the present invention, the filaments simultaneously serve as carrier threads for the explosive trickling into the fuse from the feeding hopper. For this purpose, the filaments are roughened on their surface and are pulled off a storage coil under tension and guided through the feeding hopper. Especially suitable are filaments twisted from short fibers, e.g., from rayon staple or cellulose-base fiber, fully synthetic or mixed cellulose-base fiber, wool, flax, or the like. With the aid of such filaments, it is possible, in particular, to promote and facilitate the introduction of the required amount of explosive for the manufacture of fuses having high explosive weights or having a very fine-grained explosive powder. At the same time, the detonation velocity of the fuse is substantially increased by the introduction, according to the present invention, of a lining forming a cavity.

In order to conduct the process of the present invention, i.e., the introduction of, for example, an endless tube, into the explosive core of a fuse, an apparatus is provided characterized in that a mechanical drawoff device is arranged vertically above the feeding hopper for the lining which is wound on a reel and for the supply coil of the filaments. On this draw-off device, one or more supply reels for the filaments can be provided, as well as for a so-called tracer thread for the fuse. In a particularly advantageous manner, the supply reel for the filaments is equipped with a double-thread cross winding and a hollow core and is fixedly arranged centrally above the feeding hopper. A simple ring winding is sufficient for the lining.

In order to guide the two filaments of the crosswound bobbin, a rotatable bow or bracket with opposed eyes is mounted in the zone of the cross-wound reel, so that the bow is set into rotaty motion and the threads are placed helically around the lining by the drawing-off of the filaments. The lining taken off from the reel is guided into the feeding hopper through the hollow core of the stationary cross-wound bobbin. Suitably, the cross-wound bobbin is disposed in the longitudinal axis of the feeding hopper, so that the lining enters the feeding hopper through the longitudinal axis.

A special advantage of the apparatus in accordance with the present invention resides in that the feed of the filaments and of the lining is effected without additional drive elements, solely on the basis of the removal of the continuously manufactured fuse, whereby structural simplicity of the apparatus is made possible.

However, other devices for conducting the process of the present invention are also possible such as, for example, a construction wherein a rotatable disk is horizontally arranged between the rolls, for the filaments and the lining, and the upper opening of the feeding hopper. The filament bobbins are disposed vertically on the disk, and eyes are disposed symmetrically at the periphery of the disk to guide the filaments.

BRIEF DESCRIPTION OF THE DRAWING These and further features, objects and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawing which shows, for purposes of illustration only, an embodiment in accordance with the present invention and wherein:

FIG. 1 is a cross-sectional view of the schematic progression of the process for the manufacture of a fuse in accordance with the present invention; and

FIG. 2 is an elevational view of a device for conducting the process of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWING Referring now to the drawing and, in particular, to FIG. 1, a fuse having a hollow tube 13 axially extending within the explosive core is manufactured by means of spinning machines 16 (not shown in detail) which continuously produce the casing or sheath 17 around the explosive 2 trickling out of the feeding hopper 1, the explosive being surrounded by a strip 20 or the like, show in dashed line. The explosive 2 passes through gate 19 and forms the explosive core 15. The hollow tube 13 and the filaments 4i and centering and fixing this tube in position pass, symmetrically to the longitudinal axis 18, through the feeding hopper 1 filled with explosive 2. In the zone of the outlet of the feeding hopper 1, the filaments 4 and 5, which move in a rotary motion through the feeding hopper, are placed helically around the hose 13.

FIG. 2 shows schematically the draw-off device by means of which the tube or hose 13 is introduced into the continuously manufactured fuse. Above the feeding hopper 1, which is filled with explosive 2, the crosswound bobbin 3 is fixedly arranged by mounting means 7 with the hollow core 6 of this bobbin being disposed in the longitudinal axis 18 of the feeding hopper 1, which axis simultaneously constitutes the longitudinal axis of the fuse to be manufactured.

The two filaments 4 and 5 drawn off from the crosswound bobbin 3 are guided through opposed eyes 9 of the rotatably mounted bow 8. By the continuous removal of the fuse manufactured at the outlet of the feeding hopper and thus the removal of filaments 4 and 5 from the fixedly disposed cross-wound bobbin 3, the filaments 4, 5 together with the bow 8 enter into a circularly rotating motion 10 about the longitudinal axis 18. The tube or hose 13 is provided on the reel 11 above the cross-wound bobbin and is guided in a centered position through the hollow core 6 into the feeding hopper 1. Furthermore, the tracer or identifying thread 14 of the fuse can be drawn off from the additional roll 12 arranged above the draw-off device and can be introduced into the fuse to be produced through the hollow core 6 of the cross-wound bobbin 3 and through the feeding hopper ll.

By means of this device, several problems in the manufacture of a fuse having an internal continuous cavity for increasing the detonation velocity are simultaneously solved in a simple manner. Firstly,'the hose forming the cavity is fed to the spinning machines in a centered manner through the hollow core of the crosswound bobbin and through the feeding hopper. Furthermore, the hose is fixed by the filaments wound therearound and is simultaneously protected against lateral identation. The filaments also serve as carrier threads for the explosive 2, since they continuously intersect a cone into the feeding hopper and thus take care of a constant, uniform feed of the explosive. This is particularly true in case of a very fine, dust-like explosive which does not have an inherent fluidity.

Hoses of high-strength and of flexible plastic, e.g., polyolefins, such as polyethylene or polypropylene are suitable as a lining for the cavity within the explosive core. However, other flexible materials, e.g., textiles, are likewise usable. The process of the present invention, however, is not only suitable in conjunction with fuses and the casing thereof produced according to the spinning method, but can also be employed for fuses, wherein the casings are manufactured according to different processes.

While we have shown and described an embodiment in accordance with the present invention, it is to be clearly understood that the same is susceptible of numerous changes and modifications as will be apparent to a person skilled in the art. We, therefore, do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are encompassed by the scope of the present invention.

We claim:

1. Process for the production of a fuse having an explosive core with an axially extending cavity provided with a lining, comprising:

continuously producing a casing at the lower end of a feed hopper;

introducing an explosive from the feed hopper into the casing;

passing the lining through the feed hopper;

rotating at least two filaments so as to be helically wound around the lining;

centrally guiding the lining through the feed hopper by means of the filaments; and

simultaneously introducing the lining having the filaments wound thereon together with the explosive into the casing at the end of the feed hopper to form a lined axially extending cavity within the explosive.

2. Process according to claim 1, wherein the filaments have a roughened surface for aiding the introduction of the explosive into the casing.

3. Process according to claim 1, including drawing off of the filaments from a supply reel under tension.

4. Process according to claim 3, wherein the filaments have a roughened surface for aiding the introduction of the explosive into the casing.

5. Process according to claim 1, wherein the filaments are twisted from short fibers.

6. Process according to claim 5, wherein the short fibers are selected from the group consisting of rayon staple, fully synthetic or mixed rayon staple, wool or flax.

7. Process according to claim 5, wherein the filaments have a roughened surface for aiding the introduction of the explosive into the casing.

8. Process according to claim 7, including drawing off of the filaments from a supply reel under tension.

9. Apparatus for the production of a fuse having an explosive core provided with a lined axially extending cavity, comprising feed hopper means for feeding explosive material into a casing of the fuse; reel means located vertically above the feed hopper means for supplying the lining for forming the axially extending cavity which is reeled up thereupon; bobbin means for the supply of filaments to be wound about the lining also located vertically above the feed hopper means; and draw-off means for the lining on the reel means and the filaments on the bobbin means.

10. Apparatus according to claim 9, wherein the supply bobbin means has a double-thread cross winding and a hollow core, and the supply bobbin means is fixedly arranged centrally above the feed hopper means.

11. Apparatus according to claim 10, characterized in that at least two filaments are supplied, and rotatable bow means being provided for guiding the at least two filaments, wherein the rotatable bow means has opposed eyes and is mounted in proximity to the supply bobbin means.

14. Apparatus according to claim 9, wherein rotatable disk means is horizontally located between the reel means and supply bobbin means and the upper opening of the feed hopper means.

15. Apparatus according to claim 14, wherein the supply bobbin means are located vertically on the disk means, and eyes are symmetrically provided at the periphery of the disk means for guiding the filaments.

Claims

1. Process for the production of a fuse having an explosive core with an axially extending cavity provided with a lining, comprising: continuously producing a casing at the lower end of a feed hopper; introducing an explosive from the feeD hopper into the casing; passing the lining through the feed hopper; rotating at least two filaments so as to be helically wound around the lining; centrally guiding the lining through the feed hopper by means of the filaments; and simultaneously introducing the lining having the filaments wound thereon together with the explosive into the casing at the end of the feed hopper to form a lined axially extending cavity within the explosive.

12. Apparatus according to claim 10, wherein the lining reel means is disposed above the supply bobbin means for supplying the lining to the feed hopper means through the hollow core of the supply bobbin means.

13. Apparatus according to claim 12, characterized in that at least two filaments are supplied, and rotatable bow means being provided for guiding the at least two filaments, wherein the rotatable bow means has opposed eyes and is mounted in proximity to the supply bobbin means.