US1172511A - Cap for armor-piercing projectiles. - Google Patents

Description

J. McN. ALLAN.

CAP FOR ARMOR PIERCING PROJECTILES.

APPLICATION FILED DEC.21, 1914.

1,172,51 1. Patentd Feb. 22,1916.

THB OOLUMBLA l moamlm co., WASHINGTON D c nnrrnn sraf'rns ra'rnnr orrron.

JAIEES MCNEAL ALLAN, OF SHEFFIELD, ENGLAND, ASSIGNOR OF ONE-HALF TO CAMI/IELL LAIRD AND COMPANY LIMITED, OF SHEFFIELD, ENGLAND.

GAP FOR ARMOR-PIERCING PROJECTILES.

Specification of Letters Patent.

Patented Feb. 22, 1916.

Application filed December 21, 1914. Serial N 0. 878,409.

To all whom it may concern:

Be it known that 1, James MCNEAL AL- LAN, M. I. N. A, managing director, a subject of the King of England, residing at Shefiield, in the county of York, England, have invented certain new and useful Improvements in or Relating to Caps for Armor-Piercing Projectiles; and I do hereby declare the following to be a full, clear, and exact description of the same.

This invention relates to caps for armor piercing projectiles of the kind provided with an interior cavity into which the point of the projectile extends, its object being to provide improvements in the shape or form of the cavity, such that while it still reduces resistance to perforation of the cap by the projectile its effect is also, at the moment of impact of the capped projectile with a bardened surface, to influence the distortion of the metal in the nose of the cap, which then takes place, in such a direction that it will act to support the shoulders or ogival portions of the projectile surrounding its point, instead of, as would be the case with cavities of the shapes heretofore proposed, tending to remove support by the cap metal away from those portions of the projectile shoulders adjacent to its point.

According to the present invention the cavity is in the form of a cylindrical recess or boring of comparatively small diameter, into which the point of the projectile enters, the recess extending along the major axis of the projectile from the interior of the cap toward its outer surface but not perforating the cap, although it is essential for the recess to extend a substantial distance into the cap metal immediately in front of the projectile point, at least halfway and preferably so far that only a thin portion of the cap metal closes its end.

In the specification of an earlier British Patent No. 12,281, dated May 20, 1903, granted to one of us the cap of an armor piercing projectile is illustrated as having a short boring into which the pro ectile point enters. This boring, however, was only for the purpose of facilitating the fitting of the cap to the projectile and, owing to its short length in relation to the thickness of cap metal in front of the projectile point, it did not and could not have the effects herein described as characterizing the present invention.

It is to be understood that the invention may be applied to any desired shape or construction of cap. In cases where only a very thin layer of cap metal is provided immediately in front of the projectile point covered by a false nose the cavity may extend completely through the cap metal proper provided the construction is such that the cavity is not open to the atmosphere.

In the accompanying drawings :Figure l is a sectional elevation of part of a projectile fitted with a cap according to this invention. Fig. 2 is a View similar to Fig. l showlng the approximate distortion of the cap metal following the moment of impact and Fig. 3 is a view similar to Fig. 1 illus trating a modification.

. Like letters indicate like parts throughout the drawings.

In carrying out the present invention the cap A is provided with a cylindrical recess or boring B, into which the point of the proectlle enters, the recess extending along the axial line of the projectile from the interior of the cap toward its outer surface, but not perforating the cap. The recess B is of comparatively small diameter, a suitable dimension therefor being about one fiftieth of the caliber. It is essential for the recess to extend at least half way into the cap metal immediately in front of the projectile point; preferably its length is such that only a thin portion of the cap metal is left unpierced thereby, approximately one quarter inch for a six inch projectile. With this construction it will be perceived that the point of the projectile C enters the opening of the recess B which will thus reduce resistance to perforation of the cap by the projectile on impact. But the cylindrical shape, length in relation to cap metal immediately in front of the projectile point and comparatively small diameter of the recess l3 enable it to have another and important function tending to protect the projectile while penetrating the target. For one of the earliest occurrences at the moment of impact is the flattening of the comparatively soft nose of the cap, resulting not only in shortening the length of the recess B but also in expanding it laterally into a roughly spherical shape as shown in Fig. 2. This lateral expansion of the cylindrical recess thus influences the distortion of cap metal and produces pressure on the ogival parts or shoulders of the projectile immediately adjacent to the point in a direction approximately normal to their surface. The production of such pressure serves to support the projectile point and adjacent parts to preserve them from destruction during penetration. The comparatively small diameter of the cylindrical recess is important for if it be too large there would be a liability for the point of the projectile to flare it out and thus prevent the production of the desired pressure on the parts of the projectile adjacent to its point.

Although this invention may be applied to caps of any desired shape or construction the preferred variety of caps, which give the best result, are those provided with a sul s'tantial amount of metal in front of the projectile point.

In the modification shown in Fig. 3 the invention is shown applied to a form of cap having only a comparatively thin layer of metal immediately in front of the projectile point covered by a false nose D. In this case the cylindrical recess may extend completely through the cap metal proper as shown,being closed to the atmosphere in flight by the false nose. When the false nose is of solid metal, such as aluminium, lead, copper or the like, the recess B may extend therein, but not completely through, as indicated in dotted lines in Fig. 3. Although the cap is thin immediately in front of the projectile point there is still a sub stantial amount of cap metal, at the sides, in front thereof.

WVhat I claim and desire to secure by Letters Patent is 1- 1. A cap for armor piercing projectiles of the character described provided with a recess adapted to receive the point of the projectile and extend along the major axis of the projectile at least half way through the portion of the cap immediately in front of the projectile point, said recess being of cylindrical form and of such relatively small diameter in comparison with its length and the caliber of the projectile that at the moment of impact of the capped projectile with a hardened surface the metal in the nose of the cap will be distorted in such a direction that it will act to support the portions of the projectile surrounding its point.

2. A cap for armor piercing projectiles of the character described provided with a recess adapted to receive the point of the projectile and extend along the major axis of the projectile at least half way through the portion of the cap immediately in front of the projectile point, said recess being of cylindrical form and of a diameter approximately one fiftieth of the caliber of the projectile, whereby at the moment of impact of the capped projectile with a hardened surface the metal in the nose of the cap will be distorted in such a direction that it will act to support the portions of the projectile surrounding its point.

3. A cap for armor piercing projectiles of the character described provided with a cess that is closed at its outer end by the metal of the cap and the inner end of which is adapted to receive the point of a projectile, said recess being of cylindrical form and of such relatively small diameter in comparison with its length and the caliber of the projectile that at the moment of impact of the capped projectile with a hardened surface the metal in the nose of the cap will be distorted in such a direction that it will act to support the portions of the projectile surrounding its point.

In testimony whereof I have signed mv name to this specification in the presence of two subscribing Witnesses.

JAMES MONEAL ALLAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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