US3349712A

US3349712A - Sabot projectile

Info

Publication number: US3349712A
Application number: US566850A
Authority: US
Inventors: Schwager Oskar; Engel Walter
Original assignee: Oerlikon Buehrle Holding AG
Current assignee: OC Oerlikon Corp AG Pfaeffikon
Priority date: 1965-07-22
Filing date: 1966-07-21
Publication date: 1967-10-31
Anticipated expiration: 1984-10-31
Also published as: FR1502721A; GB1102632A; BE684482A; NL6610251A; CH443060A; AT267368B

Description

4Filed July 2l, 196e Oce. si, 1967 Q, SCHWAGER Em.. 3,349,712

SABOT PRQJEGTILE 2 Sheets-Sheet l f1 0t.31,1967 -f R 3,34312 SABOT PROJECTILE Filed July 2l, 1966 2 Shee's-Shea' 2 162/ 14ga Fly.

United States Patent Oil ABSTRACT OF THE DISCLOSURE A sabot projectile wherein the sabot is connected to the projectile body by a connecting piece which can be sheared due to the inertia of the projectile when fired. This is provided by shearing edges located upon the sabot and the projectile rear surface.

The invention relates to a sabot projectile of the kind in which a sabot is connected to a base surface of a projectile -body by means of a connecting piece projecting over the base surface, which connecting piece, on discharge, owing to the load due to the inertia of the projectile body, is sheared off and causes severance of the connection.

In a sabot projectile of thi-s kind disclosed in United States Patent No. 3,044,400 granted July 17, 1962 the connecting parts are constructed as threaded bolts with bonding connections which engage in holes which are formed inthe projectile body parallel to the projectile axis. Such a projectile is difficult to produce and therefore also expensive, especially in the case of projectiles of hard metal such, for example, as tungsten carbide. A further disadvantage of such a projectile is that the holes Serving for the engagement of the bolts can be the cause of cracks which occur when the bolts which, acting on the projectile body on feeding the sabot projectile into the chamber of the barrel of an automatic weapon, transmit forwardly directed inertia force to the sabot. As a result of such cracks arising on feeding, on the sudden acceleration of the projectile body and severance of the bolts on discharge, parts of the projectile body can alre olf, cause an imbalance of the same and thus a reduction in accuracy of its flight. In the case of securing the projectile body for transport or loading through bolts of this kind provided at its rear part, such cracks radiating from the holes can, moreover, on impact of the projectile body, for example, -on an armour plate representing the target, produce a weakening of the projectile body which considerably alfects its penetrating power. With a sabot projectile of the above kind, the danger also exists that the connecting parts can break prematurely if a hard impact occurs in the chamber on loading. Here the determining factor is the shearing resistance of the adhesive bond. It is diicult to determine this resistance correctly between 'given edges on relatively small surfaces.

The invention overcomes the abovesaid disadvantages in that it provides a sabot projectile consisting of a projectile body having a base surface at one end, a discshaped connecting piece secured to the base surface by means of a bonding substance and constituting a rim extending circumferentially beyond the base surface, a sabot having the form of a sleeve in which the projectile body is received and which is closed atits rear end by a Wall portion, a ring surface forming an inner surface part of the end wall portion and dening a circular recess in the said end wall, the said ring surface co-axially seating against the rim of the connecting piece and further defining a circular shearing edge around the periphery of the recess which edge shears through the connecting piece 3,349,712 Patented Oct. 3l, 1967 ICC projectile is discharged due to the inprojectile body causing the said body to enter when the sabot ertia of the the recess.

In accordance with the invention, owing to securing the disc-shaped connecting part to the base surface of the projectile body by adhesion, the occurrence of cracks in the latter and thereby the impairment of its efliciency, is avoided. Owing to the fact that holes and screw threads in the projectile body are avoided and thus no costly machining is necessary for the projectile body consisting either of hard metal or high-alloy steel, there results the cheapening of manufacture and improvement of the sabot projectile which are sought. When measuring the resistance of the severance the determining factor is no longer the adhesive bond, but the precisely dimensionable rim of the connecting piece.

Five preferred embodiments of the invention will hereinafter be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 shows a first embodiment of a sabot projectile in longitudinal section and partial elevation,

FIGURES 2 and 2a show a greatly enlarged broken longitudinal section of the rear part of the Sabot projectile shown in FIGURE l, with section part A in FIG. 2 showing the sabot projectile in the condition prior to loading, and section part B in FIG. 2a showing the sabot projectile after discharge on passing through a gun barrel (not shown),

FIGURES 3 and 3a are a representation corresponding to FIGURES 2 and 2a of a second embodiment,

FIGURES 4 and 4a1 are a representation corresponding to FIGURES 2 and 2a, of a third embodiment,

FIGURES 5 and 5a are a representation corresponding to FIGURES 2 and 2a, of a fourth embodiment, and

FIGUR-ES 6` and 6a are a representation corresponding to FIGURES 2 and 2a of a lifth embodiment.

In FIGURE l, the sabot is marked 10 and the projectile body 11. The sleeve-shaped sabot 10, of light metal such as aluminium alloy, ts with its rear part into the mouth of a cartridge case (not shown), in a known manner, until discharge. The projectile body 11, preferably wholly or in part consisting of tungsten carbide, is cylindrical in shape and is supplemented by a leading point 21 and a short projectile body boat-tail 110, which is in the form of a truncated circular cone. The steel driving band 12 is secured to the sabot`10 and transmits to it the spinning impulse from the grooves in the gun barrel (not shown). Another similar driving band 13 is arranged at the front part of the sabot 10. In order to save weight, the outside diameter of the sabot 10 lying between the two

driving bands

12 and 13 is of smaller diameter than the base portion.

The front cylindrical hole 101 in the sabot 10 serves to centre and guide the projectile body 11. This hole 101 opens out, forming a shoulder 103, into a coaxial hole 102 of larger diameter, formed in the base of the sabot 10, the rear portion of which carries a screw thread. A screw-in body 15, with a recess 16 in it, is fitted into this screwed portion of the sabot 10 from the rear. Between this shoulder 103 and the screw-in body 15 there is clamped the disc-shaped connecting piece 14, which is secured to the projectile base surface 111.

FIGURES 2 and 2a show, in a first embodiment of the invention, the details of securing the projectile body 11 to the sabot 10. A disc-shaped connecting piece 14a, made of brass `or steel for example, is securely connected by hard soldering, by means of a layer of hard solder 24, to the truncated circular cone which forms the boattail of projectile body 11, or to its end face presenting the base surface 111. The part of the disc 14a, hereafter called the shearing rim 141, projecting beyond the diameter of the base surface 111 and the projectile body 11, bears against the ring-shaped front surface 151 of the screw-in body Iand is pressed by the latter against the shoulder 103 of the sabot 10 formed by the joint between the two

holes

101 and 102. From the front surface 151 of the screw-in body 15, extending to the rear, a recess 16a is formed, bounding a truncated cone-shaped space, contracting towards the rear, the base 16-1a of which is arranged parallel to the rear end surface 143a of the disc 14a, therefore at right angles to the projectile axis. The line of intersection of the front surface 151 with the generated surface 16211 of the recess 16a forms an edge which will hereafter be called the shearing edge 152.. Its diameter is at least as great as the diameter of the base surface 111 of the projectile body 11.

The generatrices of the truncated cone of the projectile body boat-tail 110 and the generated surface 162a of the recess 16a essentially form an angle of the same size with the longitudinal axis of the projectile. It must, however, be greater than the angle at which jamming in regard to separation of the two cones in the axial direction occurs through friction.

The height of the projectile body boat-tail 110 is, moreover, at least equal to the thickness of the shearing rim 141 of the disc 14a. In the case of this version (FIG- URES 2 and 2a) the height is for example, 1.4 times this thickess.

The distance of the base 161a of the recess 16a from the rear end surface 143a of the disc 14a, which in this example is the same as the depth of the recess 16a, is so dimensioned that it is at least equal to the thickness of the shearing -rim 141, but at most equal to the height of the cone-shaped projectile body boat-tail 110. In the case of the above version, it is equal to half the surn of the height of this projectile 4body boat-tail 110 and the thickness of the shearing rim 141.

In the case of the subsequently described embodiments shown in FIGURES 3 and 3a to 6 and 6a, corresponding parts are similarly numbered; parts altering in shape are supplemented with the lletters a to e in such figures and, in addition, new accessory components receive a new number.

The second and third embodiments of a sabot projectile illustrated in FIGURES 3 and 3a and 4 and 4a differ from the previously described embodiment as shown in FIGURES 2 and 2a, in that the disc-shaped connecting piece secured to the projectile body boattail 110 is formed by the disc 14a, containing the shearing rim 141 and, superimposed coaxially on its rear side, a truncated cone 152a or 142b, tapering to the rear, combined into one body with the disc 14a. The base surface of the truncated cone 142er has a diameter which, in the case of the sabot projectile shown in FIGURES 3 and 3a, is the same size as, and with the truncated cone 142b shown in FIGURES 4 and 4a is smaller than, the diameter of the shearing edge 152 of the screw-in -body 15.

The depth of the recess 16b is here determined, following the example of the rst embodiment in FIGURES 2 and 2a, by the requirement that the distance of its base 151b from the rear end surface 143b of the truncated cone 142a or 1,4211 is at least equal to the thickness of the shearing rim 141, but at most equal to the height of the coned projectile body boat-tail 110. In the two embodiments shown in FIGURES 3 and 3a and 4 and 4a this distance is equa-l to half the sum of the projectile body boattail 110 and the thickness of the shearing rim 141.

The angles of inclination of the generatrices of the truncated cone 14211 or 142b and the .recess 16b in relation to the base surface 111 of the projectile body are the same size.

Unlike the version as in FIGURES 2 and 2a, in which the front face of the shearing rim 141 lies in the same plane as the projectile base surface 111, in FIGURES 5 and 5a a truncated cone 147, widening to the front, is mounted on the front face of the disc-shaped connecting piece on the disc 14a containing the shearing rim 141, forming one piece with the disc 14a. The front end surface of this truncated cone is, as in the foregoing embodiments, secured to the projectile base surface 111 by a hard solder layer 24. The rear end surface of this truncated cone 147 forms the transition surface to the disc 14a and has a diameter which is at most equal to the diameter of the shea-ring edge 152..

The height of this truncated cone 147 is at least equal to the thickness of the shearing rim 141 and its cone angle is essentially the same as that of the recess 16C in the screw-in body 15. The distance of the base 161e of the recess 16e from the rear end surface 143a of the disc 14a is at least equal to the thickness of the shearing rim 141, but at most equal to the height of the truncated cone 147. In the embodiment shown in FIGURES 5 and 5a, it is equal to -half the sum of the thickness of the shearing rim 141 and the height of the truncated cone 147.

The fifth embodiment of a sabot projectile shown in FIGURES 6 and 6a differs from the embodiments shown in FIGURES 3 and 3a and 4 and 4a described above in one way; that is, the recess 1617 forms the front portion of a

hole

17, 18 completely and centrally piercing the screw-in body 15, which opens out into the base opening 104 of the sabot 10. The middle portion 17 of this hole is cylindrical, whilst its rear portion 18 widens out in a cone shape in the direction of the base opening 104. Another difference is that the disc-shaped connecting piece 14a, 142C bonded to the projectile body boat-tail is the carrier of a casing 19 arranged in the middle portion 17 of the hole and reaching through to its rear portion 18, which contains, for example, a tracer composition 20. On account of these through

holes

17, 18 during shot travel in the bore of the gun, the propellant gases do not only impinge on the base surface of the sabot 10, but also on the base surface of the projectile body 11. The relative magnitudes of these surfaces and the weights of sabot 10 and |projectile body 11 are such that the acceleration to which the sabot projectile shaped as in FIGURES 6 and 6a is subjected during this movement is considerably greater than that imparted to the projectile body 11 by the gas force. The inertia of the projectile body 11 is therefore preponderant and, as in the previous embodiments, causes the shearing through of the connecting piece.

The material of that part of the screw-in body 15 of the tive embodiments of the invention described, in which the recesses 16 are lformed, has a higher strength than the material from which the connecting pieces 14 secured to the projectile body boat-tail 110 are made.

The mode of operation of the sabot projectiles will hereinafter be described, immediately before discharge, during the loading process, and during the discharge itself.

If a cartridge, of which the sabot projectile forms a part up to discharge is suddenly checked at the end of the feeding process on loading into the chamber of an automatic gun, as a result of its forward inertial force the projectile body 11 is supported, by means of the connecting piece 14 secured to it, through the shearing rim 141, on the shoulder 103 of the sabot 10 (see FIGURE 1). In this connection, the shearing rim 141 is so dimensioned that it withstands this load caused by the inertial force, and thus no premature separation of the projectile body 11 from the sabot 10 can take place as a result of breakage of the connecting piece 14.

After the ignition of the propellant charge, however,

as a result of the enormous acceleration of the sabot projectile in the barrel of the gun, such a great inertial force acts on the projectile body 11 that, acting as a shearing punch to the' rear in relation to the sabot 10, and in conjunction with the shearing edge 152 and the front surface 151 of the screw-in body 15, which represents a counterholding shearing ring, it shears through the shearing rim 141 along the circumference of the projectile base surface 111 (see, 2a).

At the end of this shear movement, the projectile body 11, together with the sheared-

olf component

145a, 145b, 145e, 145d or 145e, supports itself to the rear, that is, according to the design version in each case of one of the ve examples, either (FIGURE 6a) through the intersecting plane 146e of the (thereby strongly compressed) component 145e against the generated surface 162b of the recess 16h, or (FIGURE 4a) through the rear end surface 143b of the component 145C (therefore without the compression of the previous example) against the base 161b of the recess 16b then acting as an abutment, or on the other hand (FIGURES 2a, 3a) through the component 145a or 145b, against these two supporting surfaces at the same time.

In each of the embodiments, the projectile body 11 is caused to rotate by the friction which acts between it and these supporting surfaces transmitting the spin of the screw-in body 15 or the sabot 10.

In the case of the embodiment shown in FIGURES 6 and 6a, which is identical with the embodiment according to FIGURES 3 and 3a as regards the supporting of the projectile body 11 on the tapered recess Wall 162b after discharge, the rearward movement of the projectile body 11 in relation to the sabot 10 on discharge comes to rest when the sum of the axial component of the reaction force transmitted by the recess wall 162b and the gas Iforce acting on it through the casing 19 is of the same magnitude as the inertia force acting on it. The conditions can be so adjusted, as with the version under consideration, that this is the case when the relative distance covered by the projectile body is equal to half the sum of the height of the tapered projectile body boat-tail 110 and the thickness of the shearing rim 141. The tracer composition 20 which may, for example, be contained in the casing 19, is ignited by the hot propellant gases during the passage of the sabot projectile down the gun barrel.

During the rearward movement of the projectile body 11 moreover, the sheared-oif ring-shaped shearing rim 141, gripped between the shoulder 103 of the sabot 10 and the ring-shaped frame surface 151 of the screw-in body 15, is also compressed on the surface of cut 144, corresponding to the shape of the tapered boat-tail 110 of the projectile body 11 (see, for example, FIGURE 2a). Similarly, the sheared-

olf component

14511, 145b, 145e, 145d or 145e, hard soldered to the projectile body boattail 110, situated in a shearing position on penetrating into the

recess

16a, 16b or 16C of the screw-in body 15, is also deformed into a truncated cone by compression on the intersecting

plane

14611, 146b, 146C, 146d or 146e.

As a result of the selection of the height of the tapered for example, FIGURE projectile boat-tail 110, together with the thickness of v the shearing rim 141 on the one hand, and the clearance existing in the condition before loading of the

recess base

161a, 161b or 161C from the rear end surface 143a or 143b of the connecting part on the other hand, the relative displacement path of the projectile body 11 in the sabot 10 is so dimensioned that the rear inside diameter of the surface of cut 144 of the shearing rim 141 is a little larger than the front outside diameter of the sheared-

oif component

145a, 145b, 145C, 145d or 145e secured to the projectile base surface 111 of the projectile body 11. By this means, and furthermore owing to the smoothing of the surface of cut 144 and the intersecting plane 146:1, 146b, 146e, 146d or 146e, the danger is eliminated with certainty that burns, or the like, arisen through dirty surfaces on the shearing rim 141 and/ or on the cut-

olf component

145a, 145b, 145C, 145d or 145e, acting as resistances should check, or even completely prevent, separation movement of the projectile body 11 in relation to the sabot 10 to be carried out by the sabot projectile after leaving the gun barrel.

The forward inertia force acting on the projectile body 11 at the end of feeding in a cartridge into a chamber URES 3, 4 and 6 (not shown in detail) causes in some cases a slight deformation of the shearing rim 141 between the place where it is gripped in the sabot 10 and the place where the soldered connection starts on the edge of the base surface 111 of the projectile body boat-tail 110, that is, a forward bending deformation of the shearing rim 141 occurs. If through this the connecting piece 14 at the periphery of the base surface 111, therefore at the most highly stressed point of the soldered connection, as a result of cracks in the latter, were to begin to come loose from the base surface 111, for example, from the impact on the chamber or during transport, the danger would occur that, after further deformation of the shearing rim or of the connecting piece, the crack could progress radially inwards .and the projectile body 11 would then prematurely separate completely from the connecting piece 14. l

With the versions as in FIGURES 3 and 3a to 6 and 6a, the truncated cone-shaped

thickenings

142a, 142b or 142C and 147 now represent a strengthening compared to the disc 14a as in FIGURES 2 and 2a through which, after a possible tearing-off of the soldered connection, this additional deformation described, and therewith the danger of a complete separation of the projectile body 11 from the connecting piece 14, are prevented.

With the arrangement of the soldered connection between the base surface 111 of a projectile body 11 and a -connecting piece 14, solder can accumulate between the front surface of the latter and the generated surface of the tapered projectile boat-tail that again solidiiies, namely either in isolated places, or in the most extreme cases on the whole circumference of the projectile boattail 110. These accumulations of solder can impede the shearing-off of the shearing rirn 141. To prevent this, the connecting part can be constructed as in FIGURE 5.

With this construction, interference with the shearing process by an accumulation of solder on the outer edge of the base surface 111 of the projectile body 11, such as is represented by ring 22 in FIGURE 5 for example, is prevented. Compression of the surface of cut 144 of the shearing rim 141 on the rearward movement of the projectile body 11 in the sabot 10 takes place here through the generated surface 147b of the truncated cone 147.

Obviously the connecting pieces constructed as in F-IG- can also be supplemented with a truncated cone 147 which, as in the version as in FIGURE 5, lies in front of the plane containing the front surface of the shearing rim 141.

We claim:

1. A sabot projectile comprising a projectile body having a'base surface at one end, a disc-shaped connectlng piece se-cured to said base surface having a rim extending circumferentially beyond said base surface, a sleeve shaped sabot for receiving said projectile body formed at one end by a wall portion, a ring surface on said'wall portion defining a circular recess in said wall portion, said ring surface coaxially seating against said rim and defining a circular shearing edge around the perlphery of said recess to shear through said connecting piece when the sabot projectile is discharged by the lnertia of said projectile body causing said base surface to enter said recess.

2. A sabot projectile according to claim 1 wherein said connecting piece is secured to said base surface by a hard solder.

3. A sabot projectile according to claim 1 wherein said connecting piece is a disc of uniform thickness.

4. A sabot projectile according to claim 3 wherein sald connecting piece is provided on its rear side with a tapering coaxial truncated circular cone.

5. A sabot projectile according to claim 4 wherein the depth'of said circular truncated cone is at least equal to the thickness of said disc.

`6. A sabot projectile according to claim 4 wherein the generating angle of said truncated cone is greater than the angle of jamming in the axial direction of said truncated cone in relation to said recess.

7. A sabot projectile according to claim 4 in which the rear end surface of said truncated cone has a diameter which at most is equal to that of the base surface of said recess.

8. A sabot projectile according to claim 3 wherein said connecting piece is provided on its front side with a coaxial truncated circular cone tapering to the rear.

9. A sabot projectile according to claim S wherein the depth of said circular truncated cone is at least equal to the thickness of said disc.

10. A sabot projectile according to claim 8 wherein the generating angle of said truncated cone is greater than the angle of jamming in the axial direction of said truncated cone in relation to said recess.

11. A sabot projectile according to claim 3 wherein the clearance of the bottom of said recess from the rear side of said connecting piece is at least equal to the thickness of said disc.

12. A sabot projectile according to claim 1 wherein said base surface is formed as a coaxial truncated circular cone tapering to the rear.

13. A sabot projectile according to claim 1 wherein said recess is a circular cone-shaped coaxial recess tapering towards the rear whose upper periphery forms said shearing edge.

14. A sabot projectile according to claim 13 wherein said upper periphery has a diameter as large as the diameter of said base surface.

15. A sabot projectile according to claim 1 wherein a casing is mounted at the rear side of said connecting piece containing material for the production of gases.

16. A sabot projectile according to claim 15 wherein said wall portion has a hole, open to the rear, accommodating said casing.

17. A sabot projectile according to claim 16 wherein a truncated cone-shaped aperture is provided in said sabot communicating with said hole.

1S. A sabot projectile comprising a projectile body having a rear surface, a sabot in which said body rests, a connecting part forming a separable mounting of said body in said sabot, said connecting part having an edge protruding beyond said body, means for fastening said connecting part to said rear surface, said sabot having a circular surface, means for supporting said edge adjacent said circular surface, said sabot having a recess surrounded by said circular surface and said recess forming jointly with said circular surface a circular coaxial edge to form a shearing means for said connecting part.

19. A sabot projectile as set forth in claimy 18 wherein said rear surface of said body is a coaxial circular truncated cone tapering towards the rear and said circular surface on said sabot is a plane coaxial circular surface and said recess being formed as a coaxial truncated circular cone tapering towards the rear with the base located in the plane of said circular surface, said circular truncated cone forming an edge with said circular surface the diameter of which is at least equal to the diameter of said rear surface.

20. A sabot projectile as set forth in claim 18 wherein said means for fastening said connecting part to said rear surface is a soldered joint.

21. A sabot projectile as set forth in claim 18 wherein said connecting part is a disc having a uniform thickness throughout said edge and wherein said connecting part is secured to said rear surface by a hard solder.

22. A sabot projectile as set forth in claim 18 wherein said connecting part is a disc having a circular truncated cone on one of its sides tapering towards the rear.

23. A sabot projectile as set forth in claim 22 wherein said rear surface of said projectile body is shaped as a truncated cone and said circular truncated cone on said disc is at least equal to the thickness of the peripheral edge of said disc.

24. A sabot projectile as set forth in claim 18 wherein a coaxial plug is mounted in the rear of said sabot wherein said circular surface and said recess is provided.

25. A sabot projectile as set forth in claim 24 wherein a casing containing a material for producing gases is provided in said plug.

26. A sabot projectile as set forth in claim 25 wherein said plug is provided with a bore extending therethrough in which sai-d casing is mounted.

References Cited UNITED STATES PATENTS 388,413 8/1889 Hawley et al. 102-93 X 1,328,247 8/1943 Alexander 102-93 3,044,400 7/ 1962 Detwiler 102-93 FOREIGN PATENTS 496,991 10/1919 France.

SAMUEL FEINBERG, Primary Examiner.

BENJAMIN A. BORCHELT, Examiner.

R. F. STAHL, Assistant Examiner.

Claims

1. A SABOT PROJECTILE COMPRISING A PROJECTILE BODY HAVING A BASE SURFACE AT ONE END, A DISC-SHAPED CONNECTING PIECE SECURED TO SAID BASE SURFACE HAVING A RIM EXTENDING CIRCUMFERENTIALLY BEYOND SAID BASE SURFACE, A SLEEVE SHAPED SABOT FOR RECEIVING SAID PROJECTILE BODY FORMED AT ONE END BY A WALL PORTION, A RING SURFACE ON SAID WALL PORTION DEFINING A CIRCULAR RECESS IN SAID WALL PORTION, SAID RING SURFACE COAXIALLY SEATING AGAINST SAID RIM AND DEFINING A CIRCULAR SHEARING EDGE AROUND THE PERIPHERY OF SAID RECESS TO SHEAR THROUGH SAID CONNECTING PIECE WHEN THE SABOT PROJECTILE IS DISCHARGED BY THE INERTIA OF SAID PROJECTILE BODY CAUSING SAID BASE SURFACE TO ENTER SAID RECESS.