# US 11,307,004 B2 · Tail portion for fin-stabilized projectile

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- Number: US 11,307,004 B2
- Document ID: US11307004B2
- Status: Granted
- Kind: B2
- Application number: 16/762,200
- Filed: 2018-09-26
- Published: 2020-11-12
- Granted: 2022-04-19
- Earliest claimed: 2017-11-10
- Assignees: Bae Systems Bofors AB
- Applicants: Bae Systems Bofors AB
- Inventors: Anders Hagberg; Tommy Ström; Jan Axinger
- Web page: https://patentgrep.com/patent/US11307004B2

## CPC

- F42B 10/14: using fins spread or deployed after launch, e.g. after leaving the barrel
- F42B 10/16: Wrap-around fins
- F42B 10/26: using spin (F42B10/04, F42B10/12, F42B10/14, F42B10/24, F42B14/02 take precedence)
- F42B: EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION (explosive compositions C06B; fuzes F42C; blasting F42D)

## Abstract

A tail portion for a fin-stabilized projectile includes at least two deployable fins, which are inclined. The fins are arranged in at least two sections, which are arranged adjacent to another in the axial direction.

## Claims

### Claim 1

A tail portion for a fin-stabilized projectile, comprising at least two deployable fins, which are inclined, wherein the fins are arranged in at least two sections, which are arranged adjacent to one another in the axial direction, the fins being made of an elastic material, wherein each fin, prior to deployment, bears against a convex bearing surface, which extends within a cylindrical, circumscribing surface which is defined by the radius of the projectile, and wherein each bearing surface coincides with a part of the envelope surface of a notional cone, the apex of which is displaced from the centre axis of the projectile.

### Claim 2 (depends on 1)

The tail portion according to claim 1, wherein each section contains at least two fins.

### Claim 3 (depends on 2)

The tail portion according to claim 2, wherein the fins which form part of one and the same section are synchronously deployable by means of a linking member, to which the fins forming part of the section are coupled.

### Claim 4 (depends on 3)

The tail portion according to claim 3, wherein the linking members in the different sections are independent of one another.

### Claim 5 (depends on 1)

The tail portion according to claim 1, wherein each fin, prior to deployment, bears against a convex bearing surface, which extends within a cylindrical, circumscribing surface which is defined by the radius of the projectile.

### Claim 6

A tail portion for a fin-stabilized projectile, comprising at least two deployable fins, which are inclined, wherein the fins are arranged in at least two sections, which are arranged adjacent to one another in the axial direction, wherein each fin, prior to deployment, bears against a convex bearing surface, which extends within a cylindrical, circumscribing surface which is defined by the radius of the projectile, and wherein each bearing surface coincides with a part of the envelope surface of a notional cone, the apex of which is displaced from the centre axis of the projectile.

### Claim 7 (depends on 6)

The tail portion according to claim 6, wherein the different bearing surfaces coincide with the envelope surfaces of different notional cones, the apices of which are displaced in relation to one another.

### Claim 8 (depends on 5)

The tail portion according to claim 5, wherein a cylindrical sleeve is arranged over the fins prior to deployment in order to hold them in place against the bearing surfaces.

### Claim 9 (depends on 8)

The tail portion according to claim 8, wherein the cylindrical sleeve can be axially pulled off from the fin sections.

### Claim 10 (depends on 8)

The tail portion according to claim 8, wherein the cylindrical sleeve is a part of a cartridge case which encloses at least a part of the projectile.

### Claim 11 (depends on 1)

The tail portion according to claim 1, wherein fins forming part of at least two sections are arranged in groups around the circumference of the projectile.

### Claim 12 (depends on 1)

The tail portion according to claim 1, wherein the fins which form part of the different sections are evenly distributed over the circumference of the projectile.

### Claim 13 (depends on 1)

The tail portion according to claim 1, wherein the front edges of the fins are bevelled.