US3744369A

US3744369A - Thermite cable cutter

Info

Publication number: US3744369A
Authority: US
Inventors: S Marziano; J Revell
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1971-07-16
Filing date: 1971-07-16
Publication date: 1973-07-10
Anticipated expiration: 1990-07-10

Abstract

An apparatus and method for severing a steel cable comprising a housing having an upper reservoir and a lower work piece holder component, a flow gate extending downward from the reservoir through the work piece holder, port means positioned at the bottom of the housing, whereby on the ignition of the thermite mixture in the reservoir component, the resultant molten mass contacts the steel cable positioned in the work piece holder for a short period of time, thereby severing the cable.

Description

States atent n 1 Marziano et a1.

THERMITE CABLE CUTTER Inventors: Samuel J. Marziano, Glenolden;

John Revel], Philadelphia, both of Pa.

The United States of America as represented by the Secretary of the Army, Washington, DC.

Filed: July 16, 1971 Appl. No.: 163,162

Assignee:

"user. .Q. 89/1 Res/1 6, 10271 R,

Int. Cl C06d 1/00 Field of Search 89/1, 1 B; 102/1, 102/66, 6, 90, 49.5; 83/16 References Cited UNITED STATES PATENTS 1/1960 McBride .4 89/1 13 [451 July 10, 1973 2,391,242 12/1945 Hurrey 102/90 2,732,153 1/1956 Frieder et al 89/1 B X 3,089,417 5/1963 Beyer et a1. 89/1 B 3,319,520 5/1967 Stefano ct a1 102/495 Primary Examiner-Samuel W. Engle AtmrmflwHarry M. Sarzlgovilz, Edward J. Kelly et a1.

[57] ABSTRACT An apparatus and method for severing a steel cable comprising a housing having an upper reservoir and a lower workpiece holder component, a flow gate extending downward from the reservoir through the work piece holder, port means positioned at the bottom of the housing, whereby on the ignition of the thermite mixture in the reservoir component, the resultant molten mass contacts the steel cable positioned in the work piece holder for a short period of time, thereby severing the cable.

2 Claims, 3 Drawing Figures THERMITE CABLE CUTTER The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to an apparatus and method for severing steel cables.

In warfare, it is sometimes necessary to destroy or sever certain installations such as steel cables. Prior art methods of destruction, e.g., high explosives or mechanical cable cutters have not been satisfactory.

The present method is based on the well known thermite welding process. In the process, coarsely powdered aluminum and iron oxide are mixed, and ignited by a fuse of magnesium ribbon and barium peroxide. A violent reaction occurs resulting in a peak temperature of over 4000?. The reaction proceeds as follows:

2Al+Fe O Al +2Fe+l85,OO0 calories The molten mass is then allowed to contact the steel cable thereby severing it in a short period of time. The molten material is subsequently removed from the system. The thermite is suitable for utilization as a destructive agent becasue of its high temperature and the erosive action of the superheated molten iron and aluminurn oxide.

It is an object of this invention to provide and disclose an apparatus for severing steel cables.

It is a further object of this invention to provide and disclose a method for severing steel cables.

Other objects and a fuller understanding of the invention may be ascertained from the following description and claims taken in conjunction with the accompanying drawing in which:

FIG. 1 is an elevated sectional view of a shell mold utilized in the present invention.

FIG. 2 is a view of the shell mold of FIG. 1 in a charged condition.

FIG. 3 is a fragmentary view of an assembled and charged system through 33 of FIG. 2 illustrating the directional attack by the molten material.

Referring now to the drawing, the shell mold comprises housing 1 1 which may be constructed of any suitable material able to withstand the effects of high temperatures, e.g., magnesia. The housing comprises upper reservoir component 13 and lower work holding component 15. Flow gate 17 extends downward from reservoir 13 along the entire length of the mold. Metal disk 18, e.g., steel, is positioned at the entrance of flow gate 17.

Illustrative but without limitations, flow gate 17 comprises a channel having dimensions of A inch width by inch in depth. Flow gate 17 in turn is connected with outlet ports 19 by groove means 21.

In operation, two half section of the shell molds are secured together by any conventional means, e.g., clamps. Reservoir 13 is filled with thermite material 23 which comprises a mixture of ferric oxide and aluminum. Steel cable 25 is positioned within work piece holder 15. The material is ignited as previously de scribed to produce molten iron and aluminum oxide. Metal disk 18 provides a slight delay in releasing the products of the thermite reaction from upper reservoir 13, thus permitting the separation of the molten iron and aluminum oxide. The molten mass filters through the cable, as indicated by directional arrow A in FIG. 3 thereby attacking the interior of the cable. In addition, the molten mass travels along flow gate 17 thereby attacking the exterior of the cable as indicated by directional arrows B and C. This results in the cable being attacked from the center outward and from the outside surface inward. Utilizing the present invention, a steel cable 2 inches in diameter was severed in a period of about 1 minute. a

Although we have described our invention with a certain degree of particularity, we wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having described our invention, we claim:

1. An apparatus for severing a steel cable by the flow of a molten mass thereover comprising; an upper reservoir designed to contain a thermite mixture, a lower work piece holder reservoir designed to hold the cable to be severed and to receive the produced molten mass, and molten mass outlet port means below the work piece holder reservoir, all components positioned in the interior of a housing; flow gate means extending downward from the upper reservoir circumferentially through the work piece holder reservoir and connecting with the molten mass outlet port means; a metal disk positioned at the entrance of the flow gate means thereby providing a slight delay in releasing the prodnets of a thermite reaction from the upper reservoir, thus permitting the separation of the molten iron and aluminum oxide.

2. A system for severing a steel cable by the flow of a molten mass thereover comprising; an upper reservoir containing a thermite mixture, a lower work piece holder reservoir having the steel cable to be severed postion therein, and molten mass outlet port means below the work piece holder reservoir, all components positioned in the interior of a housing; flow gate means extending downward from the upper reservoir circumferentially through the work piece holder reservoir and connecting with the molten mass outlet port means; a metal disk positioned at the entrance of the flow gate means; so that on ignition of the thermite mixture, a molten mass of iron and aluminum oxide slag is produced, the metal disk providing a slight delay in releas ing the products of the thermite reaction from the upper reservoir thus permitting the separation of the molten iron and aluminum oxide, the molten iron travels along the flow gate, contacting the cable and thereby severing it.

Claims

1. An apparatus for severing a steel cable by the flow of a molten mass thereover comprising; an upper reservoir designed to contain a thermite mixture, a lower work piece holder reservoir designed to hold the cable to be severed and to receive the produced molten mass, and molten mass outlet port means below the work piece holder reservoir, all components positioned in the interior of a housing; flow gate means extending downward from the upper reservoir circumferentially through the work piece holder reservoir and connecting with the molten mass outlet port means; a metal disk positioned at the entrance of the flow gate means thereby providing a slight delay in releasing the products of a thermite reaction from the upper reservoir, thus permitting the separation of the molten iron and aluminum oxide.

2. A system for severing a steel cable by the flow of a molten mass thereover comprising; an upper reservoir containing a thermite mixture, a lower work piece holder reservoir having the steel cable to be severed postion therein, and molten mass outlet port means below the work piece holder reservoir, all components positioned in the interior of a housing; flow gate means extending downward from the upper reservoir circumferentially through the work piece holder reservoir and connecting with the molten mass outlet port means; a metal disk positioned at the entrance of the flow gate means; so that on ignition of the thermite mixture, a molten mass of iron and aluminum oxide slag is produced, the metal disk providing a slight delay in releasing the products of the thermite reaction from the upper reservoir thus permitting the separation of the molten iron and aluminum oxide, the molten iron travels along the flow gate, contacting the cable and thereby severing it.