Патент USA US2405245код для вставки
Aug. 6, 1946. ‘ A. ‘E. USHAKOFF EXAMINING THE INTERIORS OF GUN BARRELS - Filed Jan. 5, 1942 2,405,245 Patented Aug. 6, 1946 2,405,245 UNITED STATES PATENT OFFICE EXAMINING THE INTERIORS 0F GUN I BARRELS Alexis E. Ilshakoff, Beverly, Mass, assignor to United Shoe Machinery Gprpbration, Fleming 1 ton, N. 'J., a ‘corporation of New Jersey Application January 5, 1942, Serial No. 425,671 ' 6 Claims. (Cl. 18--5) 2 This invention relates to examining the bore of the grooves is liable to affect disadvantageously the proper rotation of the projectile and/or its proper velocity, both of which are essential to the accurate ?ight and maximum striking power of a 'ri?edgun barrel to learn the presence and na ture of defects which may be present. In the manufacture of gun barrels, for example those of antiaircraft or antitank guns, it is cus tomary to provide in a suitably shaped barrel of 5 the projectile. _ The testing device has a generally cylindrical member I‘! having two radial ports l9 which are in communication with the longitudinal central steal a smooth bore and a communicating shell chamber; and then by a ri‘fling operation to pro vide in the bore a series of parallel spiral channels or grooves, such grooves forming the ri?ing and bore 21, the rear end of which is in communica tion ‘with a pipe 23 for compressed air from any suitable source, the ?ow of which is controlled by ‘a serving to impart rotation to the projectile when the ?nished gun is ?red. It is very desirable that three-way valve 25. The forward inturned end of there should be no defects in the surfaces of the rifled barrel since such defects are liable to af a hollow cylinder 2'! of elastic material such ‘as rubber is clamped tightly by means of a wire man re'cft adversely the shooting qualities of the gun. 15 annular groove 29 formed in a member [7; and 'The present invention provides a method and a the rear end 'of the rubber cylinder is clamped device for use in examining the interior of a gun barrel to ?nd out whether there are any defects tightly in two annular grooves 3|, 33 formed in the same member. There is thus produced an in its otherwise smooth surface, and if defects are , elastic bag which is in?ated when compressed air present to ‘learn their nature. 20 is admitted to the interior of the bag through the Referring to the accompanying drawing, pipe 23. At the forward end of the cylindrical member I‘! there is adjustably fastenedby a set Fig. 1‘ is a perspective of a vessel containing a hot liquid, for example, Water, in which a sheet screw 35 a collar 31 which has ‘a sliding ?t on the of ‘thermoplastic material of, proper dimensions surfaces of the lands l3; and on the rear end has been immersed to soften it preparatory to 25 of the cylindrical member there is fastened "by a wrapping the heated sheet around a cylindrical set screw 39a second collar 4! having a cylindri holder. cal portion to ?t the cylindrical portion pf the “Fig. 2 is a view in longitudinal median section shell chamber and a tapered portion to ?t vthe ta of the breech end of a ri?ed gun barrel with the Dered portion of said chamber. I device of the present invention in place, the hol low cylinder of thermoplastic material having been expended to take an ‘imprint of the interior of, the gun barrel. ' A sheet of heated thermoplastic material ‘133 (shown in its ?at condition in Fig. l)v ‘of the proper size is wrapped about the rubber bagbe tween the projections or collars 3'! and ‘Ill. The cylindrical member [7, with the hollow cylinder of softened thermoplastic material in place, is _ _ 7 Fig. 3 is a cross section on tile line III--III of Fig. 2'; and Fig. 4 is a perspective of the hollow‘ cylinder after it has been removed from the gun barrel so that its exterior may readily be inspected. 'In the ri?ing of a gun barrel the cuts of the ri?ing tool begin at a locality near the forward end of the shell chamber vand continue to the inserted in the breech end of the gun barrel; com; pressed air is admitted for a short interval through the pipe 23; and then ‘the supply of air is cut off and the pipe exhausted. The hollow cylinder of thermoplastic material is ?rst ex panded and then cooled, after which the testing device is slid with a spiral motion out of the gun muzzle, any defects in the ri?ing being more likely to occur during the ?rst part of the travel of the barrel and the cylinder removed. Its exterior, tool. For this reason the illustrated device for which has taken on the imprint of the lands and detecting the presence and nature of defects in 45 the ri?ing grooves, is then examined. Fig. 4 is a the surfaces of the bore is of comparatively short perspective of such a cylinder of thermoplastic length and is adapted to detect defects only in a material after it has been removed fork'insp'ection, small extent at the breech end of the bore. It there being shown a long scratch which indicates should be understood, however, that the length a defect in the bottom of one of the ri'?ing of the device will depend upon how much of the 50 grooves. _ bore it is thought necessary or desirable to ex The ‘time consumed in getting theheated cyl amine. v inder of thermoplastic material into ‘the gun bar > There is shown in Fig. 2 the rear portion of a gun ‘barrel 1 having a bore 9 which extends from the forward tapered portion of the shell chamber II to the muzzle, not shown. The ri?ed portion 55 rel, expanding it, cooling it and removing it for inspection should be short. The thermoplastic material should therefore be a fairly tough one which is solid at room temperature; it should of the bore begins a short distance from the for soften under a moderate degree of heat and ward end of the shell chamber and consists (Fig. should remain plastic and self-supporting over a 3) of lands 13 and spiral rifling grooves l‘5. Any considerable range of temperature. Solid waxes, slight defect in the surfaces of lands or those of 60 which would otherwise be suitable, are compara 2,405,245 to add toughness and to increase the range of * plasticity. Below are examples of suitable mate Example I _ _ Parts by weight , , 43.75 , V __ _ _ of its surfaces, said device comprising an elon gated member having a port which leads to its periphery, an in?atable bag fastened to the mem Castor oil __________________ -i ____ ________ 18.75 7 Parts by weight Ethyl cellulose _________________________ __ 44.00 be withdrawn for inspection. ‘3. A device for taking an impression of the in 10 terior of a gun barrel to determine the condition Opalwax #10 ____________________ __-_____'_- 37.50 Example II M 7 hering to the interior of the gun barrel and may rials. ____; _, . a heated, softened hollow cylinder of said ma terial, and exerting ?uid pressure upon the in terior of the hollow cylinder to cause its outer surface to take an imprint of the interior of the gun barrel including the ri?ing grooves, where upon the thermoplastic material sets without ad tively weak and remain plastic for only a short temperature range. In order to modify these characteristics such waxes may be combined with a resinous substance of higher molecular weight Ethyl cellulose ’. 4, 3 ber and having its interior in communication 15 with the port, spaced projections on the member constructed and arranged to permit the member to be slid into theinterior of the gun barrel and acid _____________ __' ____________ __ 19.5 to prevent movement of the elongated member radially of said barrel, a hollow member of ther Example III ' Parts by weight 20 moplastic material located outside the bag, and Opalwax #10 ______________ _.' __________ __ 36.5 Stearic Ethyl cellulose _________________________ __ 50.00 Stearic acid ___________________________ __ 50.00 means for causing a ?uid under pressure to ?ow through the port to in?ate the bag and thereby to make an imprint of the interior of the gun The ethyl cellulose is a product of the Hercules barrel upon the exterior of the thermoplastic Powder Company of the type put out by that company as “B, granular, high viscosity, 100 C. 25 member. 4. A device for taking an impression of the P.,” and any tough resinous substance of high ri?ed interior of a gun barrel to determine the molecular weight which is compatible with the condition of its surfaces, said device comprising particular wax chosen may be employed. Opal an elongated member having a port which leads wax #10 is a product of the E. I. du Pont de to its periphery, an in?atable bag fastened to the Nemours Company. The ingredients are mixed 30 holder and having its interior in communication for a. few minutes at room‘ temperature in a with the port, spaced collars adjustably fastened jacketed mixer, whereupon steam at about 80 ~ to the member constructed and arranged to per pounds pressure is turned on and the mixing mit the member to be slid into the interior of the continued until the ethyl cellulose granules are gun barrel and to prevent movement of the elon dissolved and the mass is of the consistency of 35 gated member radially of said barrel, a member heavy molasses. The mass then cools slightly, is of thermoplastic sheet material outside the bag removed from the mixer while still plastic and and located between the collars, and means for rolled into sheets from which the small sheets 43 admitting a ?uid under compression into the port of proper dimensions are out. 1 ~ for in?ating the bag and thereby making an im 40 The thermoplastic materials of the examples pression of the interior of the barrel on the outer are plastic and self-supporting at 100° 0., remain surface of the thermoplastic member. ing so throughout a. considerable range of tem 5. A device for taking an impression of the perature below 100° C., and-at room temperature interior of a ri?ed gun barrel having a shell cham are tough solids. They are‘heated by placing berin its breech and which is of larger diameter them in boiling water, are expanded by an air ratgits rear end than is the ri?ed bore and has at pressure of about 80 pounds to the square inch, its forward end a tapered portion, said device and may be withdrawn approximately one minute comprising an elongated member having a Port after they have been expanded. . The sheet 43 of which leads to its periphery, spaced projections thermoplastic ' material may conveniently be 50 on said elongated member, the rear projection heated to soften it by suspending it by means of having a tapered portion to fit the tapered por a support 49 in boiling water 45 contained in a tion of the shell chamber and the forward pro receptacle 41. 7 Having thus described the invention, what I claim as new and desire to secure by Letters Pat ent of the United States is: ' jection being of a diameter to engage the lands of the ri?ed bore, an in?atable bag located on 55 said elongated member, a hollow member of ther moplastic material located outside the in?atable bag, and means for causing a ?uid under pressure to ?ow through the port to inflatethe bag and thereby to make an imprint of the interior of the providing a thermoplastic material, heating'the gun barrel upon the exterior of the thermoplastic material to soften it, introducing into the cold 60 member. gun barrel a heated, softened hollow cylinder of 6. A device for taking an impression of the in said material, and exerting ?uid pressure upon terior of a gun barrel to determine the condition the interior of the hollow cylinder to cause its of its surfaces, said device comprising an elon outer surface to take an imprint of the interior gated member having a port which leads to its of the gun barrel including the ri?ing grooves, periphery and provided with means for centering whereupon the thermoplastic material sets with it in the gun barrel, an in?atable bag fastened out adhering to the interior of the gun barrel to said member and having its interior in com and may be withdrawn for inspection. munication with said port, a hollow member of 2. The method of taking an impression of the thermoplastic material consisting essentially of ri?ed interior of a gun'barrel to determine the 1. The method of taking an impression of the ri?ed interior of a gun barrel to determine the condition of its surfaces, said. method comprising, condition of its surfaces, said method comprising, providing a thermoplastic material consisting es sentially of a solid wax and a resinous substance of high molecular weight, heating the material to soften it, introducing into thecold vgun barrel 75 a solid wax and a resinous substance of high molecular weight located on the outside of said bag, and means for causing ?uid under pressure to flow through the port to in?ate the bag. ALEXIS E. USHAKOEE.