US1188178A - Projectile. - Google Patents

Description

W. S.' ISHAM.

PROJECTILE.

APPLICATlON FEED NOV- 18. 19M.

j Patent'd June 20, 1916.

EH10: nu q onrrno STATES PATENT OFFICE.

WILLARD S. ISHAM, OF WASHlINGTON, DISTRICT OF COLUMBIA.

rnoanc'rrnn.

Specification of Letters Patent.

. Patented Juaeao, 1916.

Application filed November 18, 1914. Serial No. 872,816.

To all whom it may concern:

Be it known that I, WILLARD S. ISlIAM, a citizen of the United States, residlng at Washington, Districtof Columbia, have invented certain new and useful Improvements in Projectiles,.as fully set forthin the following specification.

This invention relates to projectiles; andmore particularly to the type of'pro ect1les good ballistic equilibrium in flight, notwithstanding its large capacity and length; that will strike and stay inwater where other shellswill ricochet; and that will permlt the use of a nose fuse designed to be set in operation by a blow, said fuse being protected, however, from damage by the ordinary blows to which it might be subjected in handling.

Other objects of the invention will appear.

as the description proceeds.

According to the present. invention, the

charge chamber is restricted orreduced in diameter at the baseof the shell sufficiently to permit sufiicient thickness of material in.

the walls to withstand the stresses resulting when the shell is .fired; and since these stresses diminish toward the point of the. shell, the thickness-of the wallsmay be corresponding-1y decreased toward the point,,the capacity of the shell being correspondingly increased. In shells heretofore made ha ing a single charge chambensuch increase in the diameter of thechamber has been ac complished by gradually curving the chamber walls outwardly from the base toward the ooint offthe shell, the interior surface of thechamber thereby forming aconoid with its greater diameter toward the point of the shell. Such interior surfaces when used in short shells are satisfactory; but when they are employed in long shellchamhers, where the setback pressure alone may amount to 10,000 pounds per square inch or more at the base'of the chamber, it is. evident that the explosive contained in thechamberis much more highly compressed by the additional wedging action of suchsurface.- The resilting pressure in such'a shell easily reaches the critical pressure point of the explosive and" an explosion results either directly because of the excessive pressure, or indirectly because of the heat resulting from the compression of inclosed air or of gases that-may have been liberated from the explosive by more or less rapid" deterioration of the explosive after standing sometime. To, overcome this -menace in longand large chamb'e'red shells I make the inner surfaces of the side walls cylindrical and increase" the diameter toward the point by distinct steps'or oflsets as opposed to a gradual curve, to give the desired increase in capacity. By this method of construction the wed'ging efiect is eliminated and the maximum pressure in the shell charge when.

fired from thegun cannot exceed that directly due to setback; 'Furthermore, the in,-, crease in area at each offset acts as an addi,.

tional surface to receive and distribute the setback pressure, thereby reducing the pressure at the base of .the chamber. In my preferred form these offset or shoulder sur faces are augmented by annular rings or shelves extending into the chamber. These not only increase the area receiving the set-- back pressure of the explosive, -but prevent slipping or sliding of the explosive along 's' base, there by preventing "frictional heat or other abrathe walls of-the'shell toward i sive effects which might result in causing explosion of the shell charge.- The shell may also be provided interiorly with longitudinal side fins to prevent theexplosive charge from revolving within the shell because of the rotation imparted by the rifling in the gun.

The point or noseof the improved shell is made cup-shaped; and the location of this cupped nose with respect to the remainder of the shell is a matter of importance, as will subsequently appear. As the shell leaves the gun the cup receives the air equally on all its edges and discharges it forwardly from the center of the cup, thereby creating an artificial air point or cone which reduces the shells resistance in flight. It has been found in practice that the present shell ac 'tually has a longer range of.

. flight a shell having the usual pointed nose but erwise'exactly similar in form and dimenslons. r

When a shell has attained to a long range, its axis tends to incline upwardly in front and at an angle to its trajectory. 'In other "words, the shell tends always to remain parallel to its position at the instant of leaving the gun instead of following the downwar slope of its trajectory during the latter part of its flight. At long range therefore an ordinary shell is apt to strike its target with glancing instead of direct impact. With the present improved shell, however, when the shell axis tends air deflected forwardly and upwardly by the cupped nose produces a downward resultant reaction on the shell point which acts to correct the tendency to undue inclination. The corrective effect of the cupped nose is even more marked when the shell strikes water. 'The lower edge of the cup catches the water which is deflected forwardly and upwardly, producing a strong downward thrust which depresses the shell point and causes the shell to dive instead of ricocheting. If the shell is provided with a suitable delay fuse arranged to be set in action by retardation of the shell in flight, suchifor example, as that disclosed in my copending application Serial No. 838,119, filed May 12, 1914 (Patent No. 1,179,105), the shell thus be comes a mine adapted to explode at a calculable depth below the water and a definite time after striking the same. Y I y In a shell as ordinarily constructed, the cylindrical body portion tapers gently in an 'ogival curve to a point at the forward end, the rather long sharp nose thus formed diminish'ng steadyingit in flight'and thus increasing its range. This part of the shell is often termed simply the ogival. According to the present invention the ogival, instea some distance short of what may be calle the v virtual ogival point, or the point to since its range of flight is greatly decreased Furthermore such a shell tends to tumble end over end upon striking water, which the present invention successfully .avoids. If the cup or cup-shaped ndse be too nearthe virtual point of the ogival, then the desirable results attained in my improved pro ect1le are not realized because when the shell h ward resultant thrust of sufficient magn ot to incline undesirably the the resistance of the shell and of being carried to an actual point, terminates in a on Y ting edge of this strikes water there is not developed a itude to cause the shell to dive andikeepit from ricocheting.

Although the location of the cupped nose on the oglval may be varied within reasonable limits, I have found that the best location is approximately at a locality where the diameter of the ogival is about one-half the diameter of the shell. With this arrangement the requisite downward reaction on the shell nose is developed on striking water, and a perfect air point is maintained in front of the cup during flight, this air point being more effective than the usual steel point in securing long range. i r I The slope of the inner walls of the cups, that is, the angle which they make with the axis of the projectile, is another very important consideration. The size of this angle profoundly influences the magnitude of the downward thrust, on the shell nose when the projectile strikes water. I have found that for practical purposes this angle should not exceed about 45 and should be much smaller as a rule.

It has been proposed heretofore to provide projectiles with cupped noses to cause them to bite into armor plate upon impact therewith. But such projectiles have always been of the armor-piercing type and theproposed constructions have always been de signed solely, with this end in view. The proposed cups have always been shallow with obtuse cutting edges so that they would not break upon impact .with armor plate but would bite into the same. said cups have been located close to the ogival point or else at the base. The present invention is not concerned with constructions of this type and the ends sought are wholly different. Moreover, the present invention redownsigned not to pierce armor plate but to exl plode upon the impact therewith and against the outside thereof. For this reason, the cutcup is preferably made relativelythin and soft so that it will crush 1gp on striking even thin armor and permit a I w to be delivered on the fuse head contained" within said cup. The strength of the cup edges is suflicient, however, to withstand blows incident to ordinary handling.

Another important advantage of the present shell is that for a shell of given dimensionsa materially greater interior space isavailable for the high explosive with which the shell is to be charged. This results from the 'fact that the virtual length of, the present shell is greater than its actual length, owing to the formation of the air point before mentioned when the shell is in flight. This air point takes the place of the'steelo val point in shells as heretofore 'constructe It is-impractieable to pack ex 1 plate,

water or thinarmor plate, is just that much,

- provided with the usual band 12 standard length, this increase in charge capacity amounts in actual practice-to as much as25%. v

Another important advantage which results directly from the increased capacity justreferred to is that the center of gravity of the explosive charge is thereby brought somewhat nearer the point of the projectile.

of the type herein more particularly conby shock of impact against heavy armor but not by shock of impact against nearer the surface of the target when the explosion occurs, assuming impact to beat the shell point, and the effect of the explosion on the target is thus heightened to that extent. v

Obviously the broad principles of the invention may be embodied in constructions difi'ering inspecific details but all coming within the scope'of the .appended claims.

By way .of' example I have illustrated one form ofprojectile which-the invention contemplates and which has proved successful in actual service.

In these drawings: Figure 1 is a longitudinal section of a complete projectile; Fig.

'2 is an end view of Fig. 1, looking from the right; Fig. 3 is a transverse section on the line 3-3 of Fig. 1; Fig. 4 diagrammatically illustrates the position of the shell at various points in its trajectory; and Fig. 5 is a detail partly broken away and in section illustrating the use of a modified form of firing device. I

Referring to the drawings, 10 represents the hollow cylindrical body ofthe shell closed at one end by'a heavy basell, and for engag ing the gun rifling. Toward the opposite end, the shell tapers gradually from a point located approximately at 13 to form the truncated ogival which terminates abruptly at 14. This end of the shell is closed by a cupped nose piece 15, which may he integral with the shell body or which may be a separate member, secured thereto, as here shown, andwhose construction will be more particularly I described hereinafter. The cupped end thus formed is best located at a point where the ogival diameter is in the neighborhood of one-half the shell diameter. It is to. be understood that this location of the cupped nose is capable of being varied within reasonable limits, however. In any This is especially important in con-- 'nection with non-armor-piercing projectiles v case the cupped nose should be at a substantial distance from .both the base and the virtual pointof the o' ival.

As shown, the base of t e charge chamber inclosed by the shell walls'is gently 'coned as at 17 but the angle as included between the conical walls and a plane perpendicular to theshell axis should. not exceed in order to substantially eliminate all wedging effect due to pressure of the charge against these conical walls upon setback of the projectile in firlng. The lateral walls of the shell graduallyidecrease in thickness from near the base ofthe projectile toward a point approximately midway in the length of the projectile the-thickness of the walls being constant This decrease in steps as indicated at 18', 19, and 20, instead of in a curve, the inner walls of the corresponding sections 21, 22, and 23 being truly cylindrical and parallel to the shell axis. By thus 'shoulderingthe inner surface of the charge chamber, thethickness of the shell walls may be suitably reduced and the maximum capacity, of the charge chamber attained, while at the same time the dangers resulting from the wedging action occasioned by the usual curvature of the cham ber walls are entirelyavoided. The sh0u lders 18, 19, and 20 also receive a, portion of the setback pressure and thus'relieve the exrom this'point to the nose. I thickness occurs in distinct treme end of the charge chamber from the total pressure due to the setback of the charge thereagainst; and in order to increase this checking efl'ect, annular ribs or shelves 24 are optionally provided either at the shoulders as here shown, or at other 10 cations along the walls of the charge chamber. The forward, faces 25 of these ribs or shelves should. be arranged'at right angles to the chamber walls, while the rear vfaces 26 may be sloped as indicated. It will be noted that each succeeding rib of the series, looking toward the rear, as in Fig. 4, rojects an increased distance toward the shell axis. Besides serving t6 check and to distribute the total setback pressure of the charge, these annular ribs also provide gas pockets adjacent their'rear faces in whichliable to be pocketed or trapped in differ- .ent portions of the firmly packed charge, and the pressure may be suflicient' to heat them to such a temperature that they ignite and cause premature explosion of the shell 1n the gun. In the present arrangement the annular, ribs provide a means of separating the charge more or less roughly into sections, and .as these sections are compressed by setback, those portions immediately to ran the rear of each annular rib are more or less free from pressure and thus afford localities into which the gases in question may pass and collect from other portions of the charge in which the pressure has been largely increased by setback. Longitudinal ribs 26 may also be provided to prevent relative rotational movementbetween the charge and the shell body. While distinctly advantageous, they are not absolutely essential, and may be dispensed with.

Referring now more particularly to the construction of the nose piece 15, it will be seen that thismember is secured in the open end of the shell, in this instance by screw threads 27, the connection bein such that upon impact of the end of the s ell against thick armor the threads will be stripped and the nose piece or plug will be driven inwardly to compress the explosive in the shell, and thereby assist the fuse in producing an explosion. The outer face of the nose piece or plug is cupped as at 28. plug is also flanged as at 29, the outer surface of this flange forming a continuation of the ogival surface 16. The inner walls of the cup 28 extend forwardly to the cup edge at an acute angle to the axis of the shell, the angle in this instance being very considerably less than 45. The edge 30 of the cup is therefore rather sharp.

Provision is made for suitably mounting a fuse device of some kind in the cupped plug 15. In the present instance the plug is formed with a central threaded opening 31, from which may extend rearwardly a tube or hollow casing 32 closed at its rear.

end and adapted to receive the'fuse device 33 which screws into the threaded opening 31. Although here shown integral with the plug, the casing or tube may be separately formed and suitably secured to the plug. By means of the arrangement described, the fuse device may be inserted in the cupped end of the shell or withdrawn therefrom without interfering in any way with the explosive charge. This charge is to be understood as filling the entire space within the shell and to be packed tightly around the casing 32. In filling the shell, a former or core of substantially the same size as casing 32 is inserted into the shell, and explosive is firmly tamped or cast in place around it, the core being then withdrawn and the closing plug 15 being then screwed into place so that the casing 32 occupies the space previously occupied by the core.

The firing or fuse device for detonating the shell charge is most advantageously of the type described in my copending application aforesaid, being provided with a delay action train which is set in operation, as by a percussion cap and pin when the shell strikes water. By using a fuse device of this type in combination with a shell hav- The ing a cupped nose, as herein described, the shell upon striking water will dive to a certain depth during the delay afforded by the delay train,-and will then explode, thus acting like a mine. The fuse device is also best provided with quick action firing mechanism, of which the pin or plunger 34, which may be hermetically covered by thin metal 34, constitutes a. part.. Upon impact .of suitable intensity, that is, upon impact with a solid target such as armor plate, this pin is driven inwardly and operates in conjunction with other parts to produce practically instantaneous explosion of the shell. This pin or plunger is normally held out of operative position by means which are located within the fuse device and which it is unnecessary to describe here in detail. In order to still further protect the pin from accidentally receiving a blow, the fuse device is so located in the cupped plug 15 that the outer end of the fuse pin is well within the plane of the cup edges 30. These edges therefore protect the pin against accidental impact such as might result from the shell falling down an ammunition hoist'or being otherwise dropped on its end while being handled.

In Fig. 5 is shown a modified type of fuse device in which the impact firing pin 35 is normally held inoperative by a split collar or nut 36, each half of which is provided with a spur 37 or the like adapted to engage a complementary recess in the firing pin.

The sections of the divided collar are heldin the position shown by tapered pins 38 which are normally thrust outwardly by springs 39 in recesses 40' to engage correspondingly tapered grooves on the outer faces of the collar sections. These sections are therefore wedged and locked'together,

holding the firing pin from being accidentally drivenin by any blow to which it may be subjected in ordinary handling. When the shell is fired, the setback drives the pins rearwardly: into their recesses against the pressure of said springs and unhas left the gun, thus preventing the shell being jammed in the gun by one or both collar sections becoming wedged between the ogival and the rifling of the gun.

What I claim is:

1. A projectile comprising the combination, with a hollow shell of generally cylin- 'drical form inclosing a single continuous and substantially unobstructed charge chamof the series toward therear 7 means.-

her, the inner walls of said distributing setback abutments, of a charge substantially filling said charge chamber and bearing rearwardly against such steps .or shoulders.

' lindrical shell, the inner walls of which are provided with a series of annular ribs projecting toward the shell axis, each of said ribs having a forward face substantially at right angles to said axis and a rear face in clined rearwardlyfrom its inner edge to the shell wall.

4. A projectile adapted to dive on striking water and comprising a cylindrical body and a truncated ogival terminating in a cupped nose, said cupped nose having a relatively thin sharp front edge and belng located intermediate the ogival base and the virtual ogival point and at a substantial distance from both. i

5. A projectile adapted to dive-on striking water and comprising av cylindrical body and a truncated ogival terminating in a cupped nose, said cupped nose being located approximately where the diameter of the ogival is about one-half the diameterof the projectile, and the inner walls of said.

cup extending forwardly to the edge at an shell being stepped or shouldered to provide pressure-1 provided with series of an-- angle of materially less than with the axisof the projectile. 6. A projectile-adapted to'dive; on strikcupped nose or'point, the inner walls of the ing water and comprisingacylindrical and a truncated- 'ogival terminating-1111- a' cup adjacent the margin thereof being at I an angle of not more than about 45 to the proj ect1le axis. I I

In a projectile, the combination, with a shell adapted to contain a charge 'explosible by shock of impactof the projectile in flight against heavy metal but not explosible by shock of impact against water, said shell having a cupped point adapted to cause the shell to dive upon striking water, of fuse mechanism for explodmg said charge comprising a delay action tram arranged to be set in operation by impact of the shell withwater. 0

8. In aprojectile, the v'combinatlon, with .a shell containing acharge explosible by shock of impact of the projectile in flight against heavy metal but not explosible by shock ofiinpact against water, said shell having a point so formed as 'toca'use the shell to dive uponstriking-water, of a detonating device arranged tobe set in operation by impact of the shell with water and to detonate said charge 'a predetermined period-of time after'such impact.

' In testimony whereof I have signed this specification in the presence of two subscribing witnesses. M I

WILLA BD S. ISI-IAM. Witnesses: i

RF. Srnwann, James H.

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