IL36291A - Spin-stabilized sub-caliber projectile - Google Patents

Claims (3)

1. WHAT WE CLAIM IS: 1. A sub-caliber spin-stab lized projectile assembly including a projectile and a pair of sabots, one of the sabots being mounted adjacent to the rear end of the projectile (the rear sabot) and the other sabot being mounted in a forward position (the forward sabot), the sabots each consisting of a pluralit of separate angular segments secured in 'place around the projectile by an annular baVid, the sabots and the annular bands being separated from the projectile by centrifugal force after the projectile leaves the gun barrel, the rear sabot being arranged to transmit spin and thrust loads to the projectile, the annular band which surrounds the rear sabot being the driving band and the obturator which seals the propellant gas being located to the rear of the rear sabot, the rear sabot and the driving band having intermeshing surfaces to enable spin to be transmitted from the driving band to the rear sabot and the rear sabot and the projectile having intermeshing surfaces to enable spin and thrust to be transmitted from the rear sabot to the projectile, and the forward sabot being used only to center the forward part of the projectile in the gun bore, the annular band which surrounds the forward sabot being a bore rider band, the forward sabot and the projectile having intermeshing surfaces such that the forward sabot is maintained in a fixed axial position on the projectile.

2. A projectile assembly according to claim 1, wherein the intermeshing surfaces between the rear sabot and the projectile are formed by screw threads or screw thread form grooves or by a combination of screw threads or screw thread form grooves and by pins or keys which are alligned with the axis of the projectile and which intormosh between the rear sabot and the projectile, such that the spin is transmitted from the rear sabot to the projectile by frictional loads in the threads or. grooves o - by a combination of frictional loads in the threads or grooves and by shear loads in the pins or keys, the pins or keys being separated from the projectile by centrifugal force after the projectile leaves the gun barrel in the same manner as the forward and rear >.abots and the bore rider band and the driving band are. 3. A projectile assembly according to claim 1, wherein the intermeshing surfaces oetween the driving band and the rear sabot consist of threads or threads or screw thread form grooves, the quantity of grooves being as low as one (1) due to the light loads that are carried by the forward sabot during gun firing. 5. A* projectile assembly according to claim 1, wherein the bore rider band, which encircles the segments of the forward sabot, is mounted on the forward sabot by means of a screw thread or by neans of being crimped into a recess in the forward sabot or by some other means which causes the bore rider band to be a tight fit in a recess in the forward sabot, eg. by means of a shrink fit. 6. A projectile assembly according to claim 1, wherein either of or both of the forward and rear sabot segments provide a rear stop for their respective annular retaining bands-the bore rider band and the driving band, respectively. 7. A projectile assembly according to claim 1, wherein the bore rider band is made of steel, the use of a relatively hard material such as steel for the bore rider reducing the engraving (wear) of this part during gun firing the wear occuring due to the balloting action of the projectile in its travel down the gun bore and due to the centrifugal loads which tend to separate the forward sabots from the projectile, particularly during the latter part of the projectile travel down the gun bore.

3. A projectile assembly according to claim 1, wherein the distance between the forward and rear sabots is at least twico the sabot (gun) caliber. 9. A projectile assembly according to claim 1,. wherein an obturator, which is used to seal the propel lant gases, is\ mounted to the rear of the rear sabot, the obturator being provided with an annular, semi-circular in -cross-section, groove on its rear face in order to provide optimum sealing of the gas, the obturator being made of a flexible material such as high density polyethylene or some other plastic or rubber. 10. A projectile assembly according to claim 1, wherein the material of the projectile is steel and that of the sabots is aluminum alloy or c-i other ight weight, high strength material. 11. A projectile assembly according to claim 10, wherein each aperture for the keys which intermesh with the rear sabot and the projectile body has to and as illustrated in Figs. 7 to 9 of the accompanying drawings. COHEN ZEDEK & SPISBACH P. O. Box 33116 , Tel-Aviv Attorneys for Applicaat