Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS2992612 A
Publication typeGrant
Publication dateJul 18, 1961
Filing dateJul 14, 1944
Priority dateJul 14, 1944
Publication numberUS 2992612 A, US 2992612A, US-A-2992612, US2992612 A, US2992612A
InventorsCritchfield Charles L, Mcg Millar John
Original AssigneeCritchfield Charles L, Mcg Millar John
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 2992612 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

July 18, 1961 c. CRITCHFIELD EI'AL 2,992,612

PROJECTILE Filed July 14, 1944 FIG. 4. 22

BY JOHZ 5M0 6 MILLAR ORNEY United States Patent Ofiice 2,992,612 Patented July 18, 1961 2,992,612 PROJECTILE Charles L. Critchfield, Chevy Chase, Md., and John McG. Mlllar, Utica, N.Y., assignors to the United States of America as represented by the Secretary of the Navy Filed July 14, 1944, Ser. No. 544,846 1 Claim. (Cl. 102-93) This invention relates to projectiles for guns and more particularly to a novel sabot type of projectile especially adapted for attaining extremely high velocities when fired from a gun.

Generally the sabot type of projectile is a projectile having a subcaliber projectile core adapted for firing from a rifled gun. of full caliber. This is made possible by the use of a sabot of substantially full caliber which acts as a bushing or spacer between the wall of the gun bore and the aforesaid projectile core. By employing a sabot, therefore, a subcaliber projectile core can be fired from a full caliber gun, the higher pressures developed therein being used to produce higher muzzle velocities than would ordinarily be possible in a gun equal in caliber to the subcaliber projectile core. Immediately after clearing the muzzle it is intended that the sabot be discarded to reduce air resistance.

In view of the foregoing it can be seen that this type of projectile has advantages which justify its use, but due to functional difliculties encountered in the past it has not been used extensively. 1

The sabot usually is made of a light material such as aluminum alloy or plastic which, due to its yieldability under centrifugal force, does not provide proper axial centering means for the projectile core. This results in the sabot projectile as a whole tending to yaw while still within the gun bore as the projectile core becomes eccentric with respect to the axis of the gun bore. Also, difliculty has been encountered in the prompt discard of the sabot after it has cleared the gun. In certain types of projectiles the releasing of the sabot tends to upset the equilibrium of the projectile core causing it to veer from its course with the resulting possibility that it will miss the target.

One of the principal objects of the invention is to provide a sabot projectile having means for maintaining a well centered fit of the projectile core in a gun bore during movement therethrough.

A projectile made in accordance with the invention comp-rises a sabot including a base plug and a sleeve, both of a full caliber diameter, the base plug abutting the after end of a subcaliber projectile core. The sleeve tightly surrounds the subcaliber wall of the projectile core, leaving an ogive portion protruding therefrom in a forwardly direction. A camming ring is mounted in the front portion of the sleeve in an internal annular recess which is tapered rearwardly. The camming ring has an axial bore of a diameter substantially equal to that of the projectile core to provide a centering means operable during setback. The peripheral wall of the camming ring is tapered to conform to the wall of the aforesaid recess. Longitudinally of the sleeve and in symmetrically spaced relationship are radial cuts, providing zones of weakness to insure prompt discard of the sleeve. Radial cuts in the camming ring are also provided to aid in its discard.

When the sabot projectile is fired from a gun, the pressure developed in the powder chamber forces the projectile forwardly, the rifling in the gun bore engraving the turning band to produce a spinning of the projectile. The force of setback resulting from acceleration of the projectile causes the camming ring to shift rearwardly and, through the tapered surfaces, to expand the sleeve or skirt against the gun bore, thereby centering the projectile core in the gun bore and compensating for radial clearance and compressibility of the sabot. The projectile core is thus centered in its travel through the gun bore. Upon clearing the gun, the weakened zones or radial cuts allow the sabot and camming ring to break apart for discarding thereof under centrifugal force, the symmetry and precision of the radial cuts providing for simultaneous release or breaking of all segments.

Another object of the invention is the provision of a sabot type projectilewhich is stable both before and after leaving the gun bore.

A still further object of the invention is the provision of a sabot projectile which is of relatively simple construction and which is highly efiicient functionally.

These and other objects will be better understood by reference to the drawing and the following detailed description.

In the drawing:

FIG. 1 is a longitudinal sectional view of one form of the invention, some parts thereof being shown in elevation;

FIG. 2 is a longitudinal sectional view partly in elevation showing the projectile in operation;

FIG. 3 is a transverse sectional View taken on line 3-3 of FIG. 1, and

FIG. 4 is a transverse sectional view taken along line 4-4 of FIG. 1.

Referring to the drawing, and more particularly to FIG. 1 thereof, numeral 10 indicates generally a sabot for a subcaliber projectile core :16. The core 16 has an externally uniform and uninterrupted surface, that is to say it is devoid of grooves and the like, making it particularly adaptable to armor piercing. The sabot comprises a base plug 11 and a sleeve 12 having an axial bore 13, the rear end of which engages a shoulder 14 of the base plug 11. The shoulder 14 is formed by the difference in size of the major and reduced portions of the base plug, it being noted that the major portion substantially -fits the gun barrel thus to receive the full impact of the powder gas. The engagement between the base plug and the sleeve at what delineates a recess 15 may be a pressed fit, as shown, or the two elements may be threaded together. Occupying the bore 13 is the subcaliber projectile core 16 which is securely held within the bore by either a forced fit or threading. The sleeve 12, therefore, provides a coupling because of the tight fit that it has commonly on the base plug and core. The projectile core 16 is cylindrical in shape over the greater part of its length with the forward end portion terminating in an ogive 17. The ogive portion 17, in assembly, protrudes beyond the forward end of the sleeve 12.

At the forward end portion of the sleeve 12 is an internal, tapered recess 18, the diameter of which decreases as it extends rearwardly to define a shoulder 19. Closely surrounding the cylindrical portion of the projectile core 16 and in sliding engagement therewith is a camming ring 20, the periphery 21 of which is tapered to correspond to the taper of the recess wall 18 which it engages.

Radially of the sleeve 12' and the camming ring 20 are symmetrically spaced and longitudinally extending cuts 22 and 23 for providing zones of weakness to facilitate the release of the sleeve.

A turning band 26 secured to the base plug 11 in any conventional manner provides means for rotating the projectile as it moves along the rifled gun bore.

The projectile par-ts normally assume the positions shown in FIG. 1. In operation, however, when the gun is tired, the projectile will move forwardly in the gun bore (FIG. 2) and will be rotated by the action of the 3 rifling on turning band 26. The force of setback on the cam ring 20, due to acceleration of the projectile, moves the cam ring rearwardly and through the tapered surfaces '18, 21 expands the sleeve 12 into contact with the wall of the gun barrel. In this way, axial centering of the projectile core 16 is maintained throughout the entire length of the gun banrel. When the sabot projectile emerges from the barrel, the sabot in its entirety is discarded, the sleeve 12 and ring 20 breaking apart under centrifugal force. The discarding operation occurs immediately after the projectile has cleared the gun, at which time the sleeve 12 will be expanded to a point where it will be fractured along the radial cuts provided for such purpose. Inasmuch as the aforesaid radial cuts are positioned symmetrically and are uniformalily cut with respect to depth, all segments will be discarded together, eliminating the possibility of disturbing the balance of the projectile. Upon discard of the sleeve 12, the base plug 11 will become detached from the projectile core due to the greater air resistance on the plug. "0

We claim:

A missile comprising a subcaliber projectile as the core thereof, a full caliber tubular sabot providing a frictionally engaging sleeve about said core, said sabot be- 'ing slotted along substantially the axial extent thereof and to a depth Ll6SS than the radial extent of the sabot material to substantially weaken said sabot to the action of centrifugal forces, said sabot being formed with an inner conical recess in the forward portion thereof, and a tapered camrning ring substantially complementary to said conical recess slidably mounted on said core within said recess, firing of said missile from a rifled gun thereby causing said ring to cam the comically recessed portion of said sabot into close engagement with the gun barrel, and the spin imparted by the barrel causing the weakened sabot to disintegrate upon leaving the barrel.

References Cited in the file of this patent UNITED STATES PATENTS 132,903 Dana Nov. 12, 1872 2,382,152 Jakobsson Aug. 14, 1945 FOREIGN PATENTS 123,501 Great Britain Feb. 27, 1919 131,034 Great Britain Aug. 21, 1919 46,057 Sweden Nov. 5, 1919 704,406' Germany Mar. 29, 1941

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US132903 *Nov 12, 1872 Improvement
US2382152 *Jun 3, 1941Aug 14, 1945Eugene H PurdyProjectile adapter
DE704406C *Jan 20, 1937Mar 29, 1941Deutsche Waffen & MunitionsfabUnterkalibergeschoss
GB123501A * Title not available
GB131034A * Title not available
SE46057A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3148472 *Jun 11, 1962Sep 15, 1964Edward N HeggeSubcaliber projectile and sabot for high velocity firearms
US7240601 *Apr 2, 2004Jul 10, 2007Metal Storm LimitedProjectile and method for sealing a projectile in a barrel
US7934456 *Sep 25, 2009May 3, 2011Rheinmetall Waffe Munition GmbhSabot projectile
US9157716 *Sep 29, 2014Oct 13, 2015The United States Of America As Represented By The Secretary Of The ArmyShot start ring for projectile
US20050188833 *Apr 2, 2004Sep 1, 2005O'dwyer James M.Projectile and method for sealing a projectile in a barrel
US20110120336 *Sep 25, 2009May 26, 2011Rheinmetall Waffe Munition GmbhSabot projectile
DE1262830B *Sep 2, 1964Mar 7, 1968Bundesrep DeutschlandTreibspiegel fuer Unterkalibergeschosse
DE3106263A1 *Feb 20, 1981Sep 2, 1982Mauser Werke OberndorfDiscarding-sabot projectile
U.S. Classification102/522
International ClassificationF42B14/06, F42B14/00
Cooperative ClassificationF42B14/064
European ClassificationF42B14/06D