US 2350574 A
Description (OCR text may contain errors)
June 6, 1944.
L. C. TIENKEN, JR, ETAL AMMUNITION Filed July 2, 1940 A T RNEY mvsmons CZ Tien/(erz,
Mz'lzon 19.- Vora alzl Louis 20 7, WAX
mwwwwwwwm Patented June 6, 1 944- UNITED STTES AMMUNITION Louis C. Tienken, Jr., 016 Greenwich, and Milton El. Vordahl, Milford, Conn., assign'o'rs to Remington Arms Company, Inc.', a corporation of Delaware Application July 2, 1940, Serial No. 343,542
'7 Claims. ((31. 1073-43) This invention relates to the manufacture of an article composed of rolled strip material, and will be described more particularly relating to a rolled paper base wad for a shot shell. The base wad of a shot shell has the function of filling the space at the closed end of the shotshell tube, and has a hole thercthrough to allow the powder igniting charge te effect combustion of the powder contained in the shot shell directly above the base wad. The base wad must form a gas tight seal between the outer circumference thereof and the paper tube, and a seal between the powder space and the metal of the shotshell head. In
' the firing of shells, pressures of the order of 10,000 pounds per square inch are produced, so it is very important that the seal be complete, as otherwise failures will result. The base wads are usually made from strip paper or similar material. in the end of the shotshell tube. Following this, the metal or similar material head is placed over the end of the shotshell tube and a pressure is exerted upon the interior of the tube axially, so as to tightly compress the rolled paper wad and materially permanently deform the base wad, so that it will be a coherent wad and press close against the shotshell tube and the metal head. It is evident that the wad must be in such a condi- This is wound into a roll and then placed tion after axial deformation that it will remain closely adherent to the tube and will prevent gas leakage by the wad (between the wad and the tube) and will also prevent leakage through the spaces between the rolls of paper. Due to extremely high pressures that are developed, it is also necessary that the paper he in such a condition that it will not fracture and thereby allow the passage of the powder gases through the fracture.
One of the objects of the present invention is to provide a treatment for the base wad so that the paper will be in the proper condition to withstand the firing pressure without fracture, to prevent the passage of gas through the rolls of paper, and prevent the passage of gas by the base wad between the tube and the exterior surface ofthe wad. This becomes of particular importance with varying types of metal and particularly steel'shot-shell heads, because, if the head is expanded unduly by the powder pressure upon firing it' will be very difficult to extract the fired shell from the chamber of the gun.
The invention contemplates other improvements, which will become apparent from the following description.
In the drawing:
Fig. 1 is a fragmentary cross sectional elevation of a shotshell tube with the base wad in place before assembly and deformation of the base wad. Y
Fig. 2 presents a cross sectional elevation of a shot-shell head before assembly on the tube of Fistl.
Fig. 3 shows the completed assemblyof the parts of Figs. 1 and 2. 7
Fig. 4 is a fragmentary elevational'view of the assembled shotshell components of Fig. 3 after the metallic element and base wad have been placed in their final form. E P
Fig. 5 is a fragmentary elevational schematic view showing in exaggerated form the expansion of the head upon firing. 7 i
Fig. 6 is a perspective view of a rolled base wad before being placed into the shotshell tube.
Fig. 7 shows a means of placing 2. rolled base wad into the shotshell tube, and giving the base wad an additional compression.
Fig. 8 is a diagram showing the relation be tween extraction and the percent of wax in the wad.
Fig. 9 is a diagrammatic sectional view of abase wad showing the directional properties of a formed wad made in accordance with this invention.
Fig. 10 is a cross sectional elevation of a formed wad showing bulging. of the head of the shell due to the pressure of the base wad against the head when it is not headed properly. j
The invention will be described more particw larly as used in the conventional shot shellliaving a paper tube 2', rolled paper base wad 2i (Fig. 4) metallic head 22, battery cup and primer assembly 23. It is to be understood, of course, that this is merely for purposes of illustration and that changes may be made from the specific form that is shown.
As one means of winding the base wad, placing itwithin the tube and placing the metallic head thereon, reference maybe made to the patent to Hurd, No. 635,072. The present invention has particular usefulness in a shotshe ll hav ing a steel head or a head of similar metal bimaterial not having the same elastic properties as the conventional brass headed shell. The conventional brass headed shell will expand upon firing and thenreturn to its original position'so that it may be extracted with case from the chamber of the gun.
In the conventional use of a shot shellin a gun, an extractor is empl'oyed which ha h b that engages the rim of the shell and withdraws the shell after firing or upon opening of the breech mechanism in the usual manner, and if the head of the shell has become expanded and remains in this condition, it will prevent; the proper extraction of the shell from the chamber of the gun. This failure may be due to exces sive pressure necessary to pull the shell from the chamber'or from the extractor being pulled throughthe rim of the shell and leaving the.
It has been found when shell in the chamber.
or the weightof the complete impregnated wad with a wax, that satisfactory; results are obthe conventional base Wad is used in a steel shell, for example, that the base wad will fail that it will bind in the chamber of the gun and and the powder gases will bulge the shell and result in hard extraction of the shells from'the gun. It has also been found thatiftthe base terial that the base wad acts as a fluid transwad is composed of a soft plastic or similar ma mltting agent and transmits the P s u of e powder gases directly to the metallic head, which will also result in a failure of the head to perform satisfactorily.
The, paper tube. ofIFig. 1 may be formed in any of the usual manners and may have the 7 rolled base -wad 24 placed therein by a machine such as that disclosed by Hurd, No. 635,072. The rolled paper base wad 24 has a hole through the center for the powder igniting passage. rolled base wad before deformation; The paper is. rolled upon a spindle passing through thehole The 25, and takes the. form of a spiral roll. 7 head 26'. of Fig. 2 is placedupon the tube 20',
as'in Fig. 3, with the lip 21 entering the hole.
25 of the base wad. In order to have the base wad perform satisfactorily if it is deformed to Fig. 6- is a perspective view of such a the shapeshown in' Fig. 4, it is necessary that itbe treated in such a manner as to prevent the leakage of the gasby and through the base wad. It is to be understood that this treatment may take place before or after the paper has been placed in the rolled form. Itis also tobe understood that other substances besides paper may be used. In order for the'b'ase wad to perform satisfactorily, it must have aoere tain resilience in the transverse direction so that the pressure of the powder acting upon the base wad will not be able to pass between the tube of the wall '20 and the'base wad, and this seal must be maintained even when the metallic head expands outwardly under the pressure of a certain amount of waxed paper or'wax in the beater when thepaper for the wad is manufacs It is to befunderstood" that the's'e al'e merely examples of the Ways in which the wad the firing of the shell. In Fig. 5 there 'is shown,
a diagrammatic sketch of the expansion of the metallic head and paper tube under firing pressure, fsuch as shown in thedotted lines at 28 and 29. At the same time, during this outwardmoyernent of the base wad, there must be no leakage or failure in the layers of paper therein,
"soas to allow the gas to traverse the base wadin an axial direction. A certain amount of the firing pressure is taken up'in the base wad by resilience and is not transmitted directly to the head of the shot shell.
impregnated, for example, with. parafiin wax,
although it is to beiunderstood that other waxes.
besides parafllnwax may beused and other sub? stances giving the'wador paper the'proper char acteristics. This impregnation, however, must not be complete, or must not saturate the paper,v
because if the paperis saturated the wad will as 3| of Fig.6.
tained. Merely byway of example, the waxsaturation point of one paper used was about 28% of the total Weight of the impregnated Wad.
The .curve of Fig. 8 shows hardness of extraction plotted against the percent of wax in the base wad. Asa measure of-extraction, a gauge -was used-to-slip ov'er'the neck 30 -(Eig. 4) of the head of the shell. It is evident that if the neck will not pass intoa gauge of a. given size,
not allow extraction of the shell. This, of course,
is ,a more rigid test than the extractibility of a shell from the gun and gives a more positive indication of the effect "of the powder pressure on the head of the shelll mined, for example, that when, by this method,
10 to 15% of the shells fired will'not enter this gauge, that hard extraction and unsatisfactory performance will occur. It is to be noticed that there is a very marked drop as. the wax per-' centageis increased up toabout 2%, and that f up to 15%" of wax, approximately, may be used,
without again obtaining hard extraction. As the percentage of the wax is increased, as explained above, a more plastic action results, causing failure of the shell to perform satis- "factorily because of the transmission of .the pow- 'der. pressure to the head. V V a LOne'means of partially impregnating the wad "or, paper with wax consists, for example, ofdipping the formed wad of Fig 6 in a shallow bath. of wax so that one edge of the rolled paper Wad tured.
can be partially impregnated. Another. factor that affects the performance of the'shot shell is the condition of the paper of the base wad when it is impregnated. When an unwaxed dry paper base wad is deformed axially to its 'finalfor'm, therewill be but little resilience in an outward. direction or a direction that is substantially perpendicular to the axis of" the base wad. A wad such as thiswill not expand 'upon the firin of the shell, so thata' .the head As a means of accome plishing this, the shotshell wad or material is V expands outwardly there will be leakage o as between the'base wad and'the tube of the shell;
This- 11s illustrated diagrammatically inv Fig.:9.
As there will be "resiliencein' a dry wad, such as just described, in the. directions indicatedlbythe arrows 32, it is necessary fdr'the satisfactory performance of-such a wad in a. steel shell to have a resilience in the direction, "for example,
' of"thear1'0w, andthisis obtained bythe par act as a complete plastic material and will transs mit the powder pressure, as mentioned above directly to the head, and ,will cause failure thereof. It has beenfound that, if, for example,
he wad be impregnated with from 2 to 1 5% tial impregnation of the wad withla waxh. If the wad is completely impregnated with wax solthat it is plastic, there is no resilience, and-the powder pressure is transmitted directly to'thehead, as' discussed previously. If-themoisture-be reduced in the impregnated paper before it is deformed 1 or" headed, the optimum results are. obtained,
and it'has been found to be desirable to reduce th s, for example, to less than 1% moisture; If
It hasQbeen deterthere is moisture in the paper when it is deformed or headed, the results will not be as good as when there is is no moisture. The exact reason for this action is not known, but it is believed that a greater transverse resiliency remains in the wad after deformation of the wad by the heading punch in manufacture. A paper in dry form has a property which may be called stretch, that is, the amount that it can be pulled before the paper actually breaks apart. In one sample of paper, this was found to be about 1%, and the same paper, when deformed in the wad as shown in Fig. 4, did not perceptibly change in this property. However, if the paper of the wad was partially impregnated with wax before the deformation, it was found that the stretch property of the same paper after it had been deformed to the shape shown in Fig. 4, for example, was noticeably increased and in this same paper was found to be between 2 and 2 The exact reason for this is likewise not known.
Another means by which the wad may be given more resiliency in the transverse direction is shown in Fig. 7, wherein the wound wad is shown in dotted lines at 34 before it is placed in the tube 20. The die 35 having an aperture 36 with convergingwalls 31 is provided. The wad 34 is pressed through this die by a punch or suitable means and into position at 38 in tube 20. It is evident that it is compressed in the passage through the die 35.
For the best performance, it is also necessary that the wad be as tightly compressed as possible in the axial deformation thereof, so as to be completely effective as a seal to the powder gases. If a flat heading tool be used to axially deform the wad, the pressure necessary to produce the proper seal at the circumference of the wad with the paper tube will be such that it will force the base of the head outwardly, such as shown at 39 of Fig, 10. As one means of relieving this pressure adjacent the central hole and to prevent the outward projection of the head, a ring may be used on the punch forming the depression or concentric indentation 40, shown in Fig. 4. The portion of the wad at 4| is thereby slightly relieved and the wad is very tightly compressed between the ring 40 and the outer circumference 42, so as to produce the desired satisfactory results.
The problem that has been solved by the present invention is one that has been very troublesome and has prevented the proper development of many types of shot shell heads and, by the invention disclosed herein, it is possible to produce a shot shell that will perform satisfactorily and will properly extract from a gun.
It is to be understood that the invention is not limited to the details shown, and that the appended claims are to be broadly construed.
What is claimed is:
1. A shot shell having a steel head and a rolled paper base wad, a substantial portion of said base wad having a partial wax impregnation of about 2-15% of the weight of the impregnated base Wad.
2. In the manufacture of shot shells having a base wad of rolled strip paper, the method comprising partially impregnating substantially all of said strip with a wax to the extent of 215% of the weight of the impregnated base wad, and then deforming the base wad axially so as to in crease the stretchability of the paper. g 3. In the manufacture of shot shells having a rolled paper base wad, the method comprising the steps of partially impregnating substantially all of the paper with Wax to the extent of 2-15% of the weight of the impregnated wad, drying the paper, and then deforming the rolled paper Wad.
4. In the manufacture of shot shells having a rolled strip paper base wad, the method of partially impregnating substantially the entire base wad with wax comprising impregnating a portion of the wad with wax and then diffusing the wax through the wad.
5. A shot shell having a steel head and a rolled paper base wad, substantially all of said base wad having a partial wax impregnation, said impregnation being not over 15% of the weight of the impregnated wad and sufficient so that the wad has the desired resiliency and gas sealing properties.
6. In the manufacture of shot shells, having a base wad of rolled strip paper, the method comprising partially impregnating substantially all of said strip to an extent not over 15% of the weight of the impregnated wad and sufiicient to give the desired resiliency and gas sealing properties, and then deforming the base wad axially so as to increase the stretchability of the paper.
7. In the manufacture of shot shells having a rolled paper base wad, the method comprising the steps of removing the moisture from the paper of said base wad, partially impregnating substantially all of the paper of said wad to the extent of 2 to 15% of the weight of the impregnated base wad and deforming the rolled base wad.
LOUIS C. TIENKEN, JR. MILTON B. VORDAHL.