US3902353A

US3902353A - Analog gun (selection of consumable cartridge materials)

Info

Publication number: US3902353A
Application number: US467172A
Authority: US
Inventors: Miguel Anthony San
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1974-05-06
Filing date: 1974-05-06
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02

Abstract

Apparatus for testing the potential of polymeric materials for use in the manufacture of cartridges and the like is disclosed. The apparatus comprises a tube or barrel for holding a cartridge, a plate member which simulates a breech to retain the cartridge in the tube, means for simulating pressure caused by exploding gun powder, means for simulating heat caused by exploding gun powder and means for obtaining thermal data.

Description

United States Patent 4/1964 Hagy 73/l5.6

San Miguel Sept. 2, 1975 [5 ANALOG GUN (SELECTION 0} 3,369,390 2/1968 Chu et all. 73/l5.6 CONSUMABLE CARTRIDGE MATERIALS) 3,61 1,787 10/1971 D'Annessa et al 73/l5.6

7 l t A h M' 5] men or g San lguel Rldgecrest Primary ExaminerDonald O. Woodiel Attorney, Agent, or FirmR. S. Sciascia; Roy Miller; [73] Assignee: The United States of America as Lloyd E. K. Pohl represented by the Secretary of the Navy, Washington, DC. ABSTRACT [22] Flled: May 1974 Apparatus for testing the potential of polymeric mate- [21] App]. No.: 467,172 rials for use in the manufacture of cartridges and the like is disclosed. The apparatus comprises a tube or barrel for holding a cartridge, a plate member which '3; 73/ simulates a breech to retain the cartridge in the tube, means for simulating pressure caused by exploding [58] Field of Search 73/l5.6, 167, 150 g powder, means for Simulating heat caused y ploding gun powder and means for obtaining thermal [56] References Cited data UNITED STATES PATENTS 3J29087 4 Claims, 1 Drawing Figure ANALOG GUN (SELECTION OF CONSUMABLE CARTRIDGE MATERIALS) BACKGROUND OF THE INVENTION 1. Field of the Invention.

This invention relates to apparatus for use in the selection of materials for use in the manufacture of cartridges.

2. Description of the Prior Art.

Reasons for the desirability of cartridges fabricated from polymeric materials are well known. Such cartridges are lighter than conventional brass cartridges. Such cartridges are generally less expensive than brass cartridges. By incorporating oxidizers into the polymeric material, one can make the cartridges consumable, i.e., of the type which will be completely or partially consumed when they are fired. Reasons for the desirability of consumable cartridges are also well known but need not be gone into here.

Prior art polymeric cartridges have left much to be desired insofar as their qualities are concerned. Some do not have adequate tensile strength to withstand the stresses and strains that they are subjected to when they are handled and loaded. Some do not have enough heat resistance to tolerate being loaded into a gun which has been heated by repeated firings. Some build such pressures within the gun barrel when they are consumed that they are unsuitable. Some consumable cartridges, in spite of the claims made for them, simply are not consumed under ordinary firing conditions. Many of these and other problems could be alleviated if methods and apparatus for testing candidate polymeric materials were improved. Insofar as is known by the inventor, the only prior art way by which polymeric cartridges have been tested under actual firing conditions 'BRIEFDESCRIPTION OF THE DRAWING The single FIGURE is an exploded, perspective view of apparatus according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS tested.

In the drawing, the numeral 11 indicates a tubular or barrel member into which a cartridge or portion thereof 12 which is to be tested is inserted. In one embodiment, an end plate 13 having a threaded center hole 14 in it is fastened to the cartridge by means of a threaded rod 15 which is screwed through hole 14 and through a threaded hole (not shown) in the cartridge to draw the cartridge and end plate closely together. The threaded rod physically simulates an ignitor. In the embodiment being spoken of, a contoured mandrel 16 y is drawn into the cartridge 12 by means of threaded rod 15 to simulate pressure produced when a cartridge is fired. Naturally, in order to do this, the contoured mandrel must have a threaded hole (not shown) which rod 15 is screwed into. To simulate heat produced by exhas been to fabricate cartridges, load them, place them SUMMARY OF THE INVENTION The present invention resides in apparatus for obtaining relevant data on polymeric materials which are potentially suitable for use in the manufacture of cartridges. The apparatus is analogous to a gun in that it simulates firing conditions produced by a gun. It is advantageous over a gun in that tests relating to pressure and temperature can either be performed simultaneously or individually. The apparatus comprises a barrel in which a cartridge or portion thereof to be tested is placed, an end plate to simulate a breech mechanism and hold the cartridge in place, a contoured mandrel which can be forced into the cartridge and utilized to simulate gas pressure produced by exploding gun powder and a connecting rod to simulate the cartridges igniter. One or more thermocouples connected to the cartridge through holes in the end plate are utilized to provide thermal data and exhaust gases from a gas generator are used to simulate temperatures and heat flux produced by exploding gun powder.

ploding powder a gas generator 17 is utilized. In the drawing, the gas generator is depicted as a rocket but other gas generators could be utilized.

In the embodiment of the invention being discussed, pressure is simulated relatively slowly by drawing the parts (mandrel, cartridge and end plate) together slowly with rod 15. And, when the gas generator is activated to produce gases which simulate heat which would be produced by exploding powder, a plurality of thermocouples 18 attached to the cartridge through small holes 17 in end plate 13 and to one or more recording instruments l9 remote from the analog gun of this invention are utilized to record temperature information. It may also be desirable to attach thermocouples 20 to the end plate itself which simulates a breech mechanism and to a recording instrument. The end plate acts as a calorimeter and data obtained by taking heat measurements from it can be useful. The recording instrument may be an analog tape recorder which records voltage data from the thermocouples. In this way, data obtained can be handled at liesure later by well known methods.

In a second embodiment of the invention, rod 15 may be attached, by means of threads to mandrel l6 and, at its other end, to a pressure jack (not shown) located behind the apparatus with the center portion of the rod being smooth so that it will slide freely through the holes in the cartridge and the end plate. In this embodiment, pressure may be applied very quickly by activating the pressure jack and pulling the countoured mandrel into the cartridge. It should be noted that this embodiment more closely approximates what actually happens (insofar as pressure is concerned) when a cartridge is actually fired than does the first embodiment. When a cartridge is fired, pressure quickly builds up for approximately 5 milliseconds and then subsides.

Apparatus according to this invention may be utilized in many different ways. For example, data having to do with what happens when pressure builds up within a cartridge may be obtained by slowly drawing mandrel 16 into Cartridge 12. As another example, data having to do with what happens insofar as pressure is concerned may be obtained by utilizing a pressure jack and rod to quickly jerk mandrel 16 into cartridge 12. As another example, data on the effect of heat alone may be obtained by simply firing gas generator 17 into cartridge 12 while the cartridgeis imprisoned in the tube 11 by means of end plate 13. As another example, data may be obtained by simultaneously applying pressure and heat .to'the cartridge. 7

If it is desired, a plate may be placed between the gas generator and the end of tube 1 1 so that the gas generator can be activated and its exhaust gases allowed to build up to any desired temperature. Then, at any selected time, the plate can be removed to allow the full force of the heat to suddenly hit the cartridge.

Since it will be desired to obtain heat measurements while mandrel 16 is inserted in cartridge 12, it is preferred that mandrel 16 be fabricated from a material which conducts heat well. Either aluminum or copper is satisfactory and there are undoubtedly other satisfactory materials as well. Since the end plate must act as a calorimeter, it is preferred that it be fabricated from a good calorimetric type material such as very pure iron. Armco iron is satisfactory. The other parts of the apparatus (tube, rod and gas generator) may, of course, befabricated from steel or similar materials from which, guns and gas generators are ordinarily fabricated. Those skilled in the art of obtaining thermal data will, of course, have no difficulty in knowing what the thermocouples and related instruments are fabricated from.

; The instant invention has been described as being re- I .lated to apparatus for determining the suitability of polymeric materials for use in the manufacture of cartridges. It will be recognized that the apparatus of this invention could be used to conduct tests on polymeric materials which are candidates for use in either consumable or nonconsumable cartridges. It will also be recognized that the apparatus of this invention could be used to conduct tests on materials, other than polymeric, which are candidates for use in the manufacture of cartridges. The evaluation of rim removal designs can also be performed.

What is claimed is:

1. Apparatus for obtaining data concerning the effects of heat and pressure on a material comprising? a tube member to receive said material;

an end plate adapted to retain said material in said tube member having a threaded center hole which permits the material to be fastened to it by means of a threaded rod and a plurality of small holes through which temperature measuring apparatus can be inserted and attached to the material;

means for applying pressure to said material;

means for applying heat to said material; and

means for measuring and recording the heat applied to said material.

2. Apparatus according to claim 1 wherein the means for applying pressure is a contoured mandrel which is drawn into the material by means of a threaded rod.

3. Apparatus according to claim 2 wherein the means for applying heat is provided by hot exhaust gases from a gas generator.

4. Apparatus according to claim 3 wherein the means for measuring and recording heat comprises at least one thermocouple and one recording instrument in

Claims

1. Apparatus for obtaining data concerning the effects of heat and pressure on a material comprising: a tube member to receive said material; an end plate adapted to retain said material in said tube member having a threaded center hole which permits the material to be fastened to it by means of a threaded rod and a plurality of small holes through which temperature measuring apparatus can be inserted and attached to the material; means for applying pressure to said material; means for applying heat to said material; and means for measuring and recording the heat applied to said material.

4. Apparatus according to claim 3 wherein the means for measuring and recording heat comprises at least one thermocouple and one recording instrument in combination.