US1044360A - Method of and means for protecting the bores of heavy guns from erosion. - Google Patents

Description

F. N. DU BOIS.

METHOD OF AND MEANS FOR PROTECTING THE BORES OP HEAVY GUNS FROM EROSION.

APPLIGATIOH' FILED APR. 25, 1910.

Patented Nov. 12, 1912.

IX) i/bwa-oaeo Maw "UNITED STATES Paras EEC;

FREDERICK N. DU BOIS, OF NEW YORK, N. Y.

'hiIETHOID or means ron rn'o'rncrmc THE BORES or HEAVY cons FROM EROSION.

Specification of Letters Patent.

Patented Nov. 12, 1912.

To all whom it may concern Be it known that I, FREDERICK N. DU

Bors, a citizen of the United States, and a resident of the borough of Manhattan, in

the county, city, and State of'New York, have invented certain new and useful Improvements in the Method of and Means for Protecting the Bores of Heavy Guns from Erosion, of which the, following is a speci fication. In the use of heavy guns of the modern high power class'it has been found, that, at each discharge, the walls of the bore, when a projectile is employed, are so eroded either by the enormous pressure to which they aresubjected by the gas evolved in the burning of the explosive, or by the heat liberated thereby, or by both together, that after a certain number of discharges, usually less than'one hundred, the walls of the bore are so eaten away as to render the gun moperative and incapable of further use, until the same is re-bored, a bushing supplied, and the gun re-rifled, which, in consequence of the necessity to dismount the gun and transportit to the factory, is an operation that notonly involves'much time, but great expense as well.

The object of my invention is therefore, to obviate this defect; and, to this end, the invention ,consists in the method of and means for applying a coating of metal under pressure to the eroded portions of the walls of the bore at or after each discharge of the gun, whereby a fresh metallic surface ispresented thereby to the action of the gases and beat, all' as will hereinafter more fully appear. I 7

Referring to the accompanying drawing, which forms a part of this specification, Figure 1, is a side elevation, partly in axial section, of a portion of a gun, showing in side elevationa projectile constructed in accordance with my invention, and a cartridge arranged in the chamber in rear thereof; Fig. 2, a side elevation of a projectile constructed in accordance with my invention. wit-ha portion at its butt broken away and shown in section,to more clearly illustrate the invention, and Fig. 3, an enlarged sectional fragment of the butt of a projectile, showing the arrangement of the abrasion band thereon. V

In the several figures, like letters of ref,

erence are employed to designate corresponding parts.

A indicates the rear or breech portion of a cannon or other piece of heavyordna-nce, which is or may be constructed of any ordinary or well known form. As shown in the drawing however, it follows the general line of construction of the ordinary modern breech-loading high power gun,'and is provided with the usual rifled bore a and breech opening and closing mechanism (not shown), and also with a charge-receiving chamber a at the rear end of the bore a, as is common with guns of this character as ordinarily employed. In being thus constructed, the gun, when in operation, receives within the chamber a the required charge, comprising the projectile B and the bag of explosive C; and the discharge of the projectile therefrom is effected by burning the explosive within the bore a and chamber oi the result of which is to generate a sufiicient volume of gas and set free the requisite amount of heat to violently expel the projectile from-the bore of the gun and carry it forward in its trajectory to its place of destination. To accomplish this ejection and propulsion of the projectile at the excessively high speed and to the great distance desired, it is obvious that the pressure exerted by the consumption of the explosive within the boreof the gun is enormous and exceeds at times more than fifteen, if not twenty, tons to the square inch.

With guns of the present high power class and with the use of modern smokeless and other excessively strong acting explosives, the pressure exerted by its consump tion is so extremely great, that in ejecting the projectile from the gun and carrying it forward in its flight, it acts upon the walls of the bore a with such a tremendous force that it erodes and eats them away to such an. extent as to completely obliterate the lands a between the grooves a of the rifling, and render the gun wholly useless after a certain number of shots have been exceed one hundred shots in all. I have discovered however that this erosion and eating away of the walls of the bore may be obviated in whole or in part, by-applying fired, which, in practice, seldom or never 7.

'to the surfaces of these walls, a metallic coating under pressure at or before each discharge of the gun in which a projectile is, or is to be, employed. While the metals that may be adopted to this end are of various kinds, I have found that bronze, made up as an alloy from copper and tin is the most efiicient for the purpose, since when forced against steel surfaces under great pressure, it adheres thereto so firmly and tenaciously as to almost aniount to an actual weld, and when applied to the walls of the ing band 5 and supports the bronze coating material, which is preferably'made in the form of a ring'b and is disposed in a suitable groove formed circumferentially around the conical body 6, in rear of the groove engaging band 6 as shown. This ring if, which, for convenience of description I shall hereinafter designate an abrasion ring, is preferably though not necessarily made of the same diameter as the groove-engaging band 5 whereby to engage with the lands of, and, at the same time be pressed against the bottom of the grooves o in moving along the bore a, as the projectile is ejected from the gun. In being thus engaged with the lands a and pressed out ward against the bottom of the grooves (1 it is obvious that-the abrasion ring 0 in being carried forward by the projectile over any roughened or eroded surface in the walls of the bore a, will be engaged thereby and the portions thereof thus engaged will be abraded away by such engagen'ient, with the result that the portions of the material thus abraded and carried away will, in consequence of the pressure exerted between the ring and the walls of the bore, be forced into the depressions formed. in the walls of the b re by such erosi n and thereby adhere so firmly to the material of the gun to form a practically fixed surface of this bronze material upon the interior of the bore over the roughened portion thereof, against which the gases and heat may act. at the next discharge of the gu n. In order therefore to provide for pressing this abrasion ring D out-ward into contact'with the walls of the bore a with the requisite degree of pressure, the groove 6 in which the ring is located, instead of being made with vertical side walls, has its front walls 6 inclined forward from its inner to its outer edge, uhcreby to act as an expandward upon the inclined walls of the groove 71 when the explosive is consumed, the rear walls 6 of this groove are inclined rear-' wardly to a slight degree from their inner to their outer edges, with an annular rabbet Z) formed around their outer edge, whereby to permit of the engagement of appropriate tongs or other retracting means with the projectile when the withdrawal of the latter from the gun. is desired. \Vith the rear walls of the groove b 'thus backwardly,

inclined, the free action of the gases evolved by the eonsumptionof the explosive against the rear edge of the abrasion ring b throughout its entire extent is permitted; and, in order to allow of the forward movement of this ring upon the inclined walls I)" of the groove 6 and with a View to preventing it from fixedly adhering to the body 6 ofthe projectile when acted upon by the gases and heat, the groove 6 is made somewhat wider than the ring 6 and a layer of lubricating material N, such, for instance, as graphite or plumbago is interposed between the front edge of the ring and the forward inclined walls (2* of the groove b,

as shown. With the abrasion ring 19 thus supported and carried by the projectile, a metallic coating is applied to any eroded or otherwise roughened surface that may be present within the bore a and firmly ad hered or secured thereto at each discharge of a projectile from the gun. In the construction of the abrasion ring b the mate'- rial of which it is composed, while possessed I of; a less degree of hardness than the material of the gun itself, is preferably somewhat harder than the groove-engaging band 6 whereby to resist the scraping action of this groove-engaging band in passing over and in contact with the material of the abrasion ring previously applied as a coating to the eroded or other roughenedsurfaces of the bore a. lVith the abrading ring 6 thus secured to and carried by the projectile B, the walls of the bore of the gun will be unaffected thereby when it is passed over them and the walls are free: from erosion or other roughness. W'hen however-these walls are eroded or otherwise roughened, then in the abrading ring being carried forward over them by the projectile, the abrasion of this ring by the roughness ofv the walls will be effected, and the portion thereof thus abraded away will be deposited in the depressions formed by such roughness and firmly adhered or secured therein, with the result that the portions thus coated with 7 the abraded material will present a smooth surface to the action of the gases and the heat respectirely generated and set free at the next dischar e of the gun, and so on.

From the foregoing therefore it will be seen, that I not only protect the bore of'a gini from erosion by the action of the gases and heat respectively generated and set free by the discharge of the gun, but also provide means by which that protection is effected.

Having thus described the invention, and specified certain of the Ways in which it is or may be carried into effect, I claimand desire to secure by Letters Patent of the ened and eroded surface portions as the projecile is forced through the gun bore, the

abraded portions of said encircling member a being applied to the gun bore under pressure substantially at the time it is abraded.

In testimony whereof, I have hereunto set 35 my hand in the presence of two Witnesses this 19th day of April, 1910.

FREDERICK N. DU BOIS.

Witnesses:

THOMAS GANNON, GRACE T. DIXON.

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