One-piece foldable calibre gauge ring

Abstract

The present invention relates to a weapon barrel (10) having a foldable calibre gauge ring (20), wherein the calibre gauge ring (20) can be moved from a first position into a second position, wherein in the second position, the calibre gauge ring (20) reduces the gap between the wall of the weapon barrel (10) and the weapon (50) arranged in the weapon barrel (10), wherein in the first position, the calibre gauge ring (20) rests against the wall of the weapon barrel (10), characterised in that the calibre gauge ring (20) is designed in one piece, wherein the calibre gauge ring (20) can be pivoted about a horizontal axis of rotation (22) between the first position and the second position.

Description

[0001] December 4, 2025

[0002] 1 / 15

[0003] One-piece hinged caliber ring

[0004] The invention relates to a caliber ring which is hingedly arranged in a gun barrel and is made in one piece.

[0005] A caliber ring is inserted into a gun barrel to close or minimize the gap between the weapon and the barrel wall. This serves to reduce the amount of air flowing past the weapon during a pressure release, particularly a compressed air release, thus maximizing the weapon's acceleration.

[0006] Unlike a pressure vent, self-launching torpedoes utilize the gap between the weapon and the barrel wall to allow water to flow past the torpedo, filling the resulting void behind the weapon. In this case, no caliber ring is used because the resulting resistance to the flow of water would slow the weapon down.

[0007] With self-launching torpedoes, the challenge lies in ensuring that, in the event of a malfunction, the torpedo can be reliably ejected from the tube, but it cannot leave the tube under its own power. Therefore, it is desirable to equip the tube of a self-launching torpedo with a pressure ejection mechanism to reliably expel a torpedo that fails to launch in an emergency. However, this presents the challenge that a wide gap is typically required between the torpedo and the tube wall, while a caliber ring is needed for emergency ejection. Therefore, German patent DE 102020201 226 B3 proposes a hinged, two-part caliber ring. However, experience has shown that the forces involved in pressure ejection are comparatively large.

[0008] A gun barrel is known from DE 102019216604 A1.

[0009] German patent DE 102023 134636 A1 discloses a pressure discharge from a weapon located in a container within a weapon tube. 04.12.2025

[0010] 2 / 15

[0011] The object of the invention is to provide a hinged caliber ring that is particularly well able to absorb the strong forces occurring during pressure ejection.

[0012] This problem is solved by the weapon barrel with the features specified in claim 1. Advantageous further developments are described in the dependent claims, the following description, and the drawings.

[0013] The gun barrel according to the invention has a hinged caliber ring. The caliber ring is movable from a first position to a second position. In the second position, the caliber ring reduces the gap between the wall of the gun barrel and the weapon arranged in the gun barrel. In the first position, the caliber ring rests against the wall of the gun barrel, thus leaving ample space for a fluid, in particular water or air, to flow between the weapon and the wall of the gun barrel.

[0014] According to the invention, the caliber ring is made in one piece. Furthermore, the caliber ring is pivotable about a horizontal axis of rotation between the first and second positions. It has been shown that the one-piece design, which pivots horizontally and thus conforms to the weapon from above and below, allows for much better dissipation and compensation of the forces than in the two-piece arrangement, as shown, for example, in DE 102020201 226 B3. As a result, the hinged caliber ring remains more reliably in position even under the high stress of the pressure ejection, leading to improved ejection.Due to the pivoting around a horizontal axis of rotation, the forces acting on the upper and lower halves during ejection act in opposite directions, and due to the one-piece design, these largely compensate for each other, leading to a stabilization of the caliber ring and thus to a more reliable ejection.

[0015] Preferably, the caliber ring is rigid in its shape. In this context, rigid means in particular that it is not deformable and that adaptation to the caliber is not achieved by an overlap of several parts of the caliber ring relative to each other, as with an iris diaphragm, or by elastic deformation, such as by inflation. Adaptation to the weapon caliber is achieved by a displacement of a fixed shape in its position relative to the weapon barrel. (04.12.2025)

[0016] 3 / 15

[0017] The rigid shape allows the high forces during ejection to be absorbed and dissipated more effectively.

[0018] The caliber ring according to the invention allows for a particularly low resulting torque at the caliber ring. Therefore, a corresponding control element for switching between the first and second positions can be designed to be correspondingly small or requiring little force. In further preferred embodiments, even complete rotation of the torque can be enabled. In these cases, the caliber ring would automatically remain in the gap-closing position.

[0019] A truly ring-shaped caliper ring is significantly superior to two individual vanes, an iris diaphragm, or an inflatable caliper ring in handling the forces encountered during pressure discharge. In the one-piece design according to the invention, the two necessary pivot points are positioned as far apart as possible. A rotational axis is defined by these two points, and this axis is also positioned as far away as possible from the pivot point. This ensures that the forces are optimally dissipated.

[0020] In a further embodiment of the invention, the caliber ring is shifted at its lowest point further inward toward the boat's interior in the first position and further outward toward the muzzle, i.e., the muzzle flap, in the second position. This means that the lowest point is pivoted in the direction of ejection. Preferably, the caliber ring is secured by means of an end stop, which also serves to reliably dissipate forces. Especially in the lower region, stabilization against the forces acting during ejection can thus be achieved particularly easily. In this case, the upper part of the caliber ring, on the other hand, generates a restoring torque due to the flow. The two torques that arise in the upper and lower halves almost cancel each other out. By optimizing the component geometry, it is therefore possible to deliberately set the ring to be held open, torque-neutralized, or closed.This is achieved by adjusting the surfaces above and below the axis of rotation. However, this only significantly reduces the resulting torque. 04.12.2025.

[0021] 4 / 15

[0022] or rather, reduced to zero, meaning the forces that can cause unwanted rotation and thus pivoting between the first and second positions. Despite this, however, the oncoming force on the caliber ring surface remains extremely high. The caliber ring must therefore be very rigid between its upper and lower halves relative to the axis of rotation, which is why a one-piece rigid design is highly advantageous.

[0023] In a further embodiment of the invention, the gun barrel has a moving device for moving the caliber ring between the first and second positions. The moving device is arranged below the position for the weapon. Firstly, the available space is usually greatest in this location. Secondly, this arrangement allows the moving device to stabilize the caliber ring during ejection, since the weapon is usually not positioned centrally but slightly upwards within the gun barrel. This results in a larger gap under the weapon and thus greater forces acting on the caliber ring, which can then be transmitted more easily and directly to the moving device, thereby further stabilizing the caliber ring.

[0024] In another embodiment of the invention, the actuating device is a hydraulic actuator. An electrical or mechanical actuation would be more complex and prone to failure, as the mechanism would have to be routed from the ship's interior to the interior of the pressure hull. With a hydraulic system, however, the routing is significantly simpler and less susceptible to failure. Furthermore, a hydraulic actuator has the advantage of being easily fixed in place and capable of withstanding high forces in various positions. This allows not only two end positions (open and closed) but also intermediate positions. This can be used, for example, to adjust the ejection speed, such as when the weapon (or storage container) to be ejected is not intended to be ejected at maximum velocity.

[0025] In a further embodiment of the invention, the motion device comprises a hydraulic circuit and at least one limit switch. The hydraulic circuit and the limit switch are connected in such a way that only after December 4, 2025

[0026] 5 / 15

[0027] The extension of the movement device is hydraulically activated by the limit switches. This prevents premature activation of the limit switches and ensures that a stabilizing pressure is maintained in the movement device at the end position, thus holding the caliber ring particularly stable, especially in the second position.

[0028] In a further embodiment of the invention, the propulsion device is connected to the vehicle's hydraulic system. This enables not only emergency ejection but also, for example, the use of rockets that must be actively moved out of the gun barrel. Here, too, forced ejection with air or water is a suitable method and necessitates the caliber ring. The rocket, thus accelerated, is only ignited after being ejected from the gun barrel to prevent damage to the barrel from the ignition energy. The connection to the vehicle's hydraulic system ultimately also simplifies the simultaneous readiness of all gun barrels for use.

[0029] In a further embodiment of the invention, which considers only the emergency deployment, the movement device is connected to a manual pump. Since the use for the pressure release of a gun tube for otherwise self-launching torpedoes is more of an emergency system, the use of a manual pump for hydraulic actuation results in a method that is independent of all other ship systems and also functional in the event of damage.

[0030] In a further embodiment of the invention, the movement device is connected to the vehicle's hydraulic system, as described above. In addition to the connection to the vehicle's hydraulic system, the hydraulic control block required for control also provides an adapter for a manual hand pump, or the manual hand pump is permanently integrated into the hydraulic control block. This measure allows the vehicle's hydraulic system to be bypassed in the event of damage, particularly to the hydraulic system itself.

[0031] In a further embodiment of the invention, the caliber ring in the first position has an annular cross-section transverse to the gun barrel. In the longitudinal direction of the 04.12.2025

[0032] 6 / 15

[0033] Viewed from the perspective of the gun barrel, with an annular cross-section, the caliber ring is a ring with the smallest possible cross-sectional area running longitudinally around the weapon, and it itself typically has a circular cross-section. However, the ring is not closed at its upper end. Due to the annular cross-section, the flow resistance is minimal. In the first position, which is crucial for normal operation, the fluid, especially water or air, can thus flow relatively unimpeded between the torpedo and the gun barrel wall of a self-launching torpedo, even past the caliber ring, and therefore the torpedo's launch is not significantly hindered.

[0034] In a further embodiment, the contour of the caliber ring is predominantly defined by a surface formed by, on the one hand, the cylindrical surface of a first cylinder with a diameter smaller than the diameter of the gun barrel and larger than the diameter of the caliber plus half the difference between the diameter of the gun barrel and the caliber. The contour is further bounded by the fact that, in the second position and thus tilted relative to the first position, the caliber ring is penetrated by a cylindrical surface of a second cylinder, the diameter of which is larger than the diameter of the caliber and smaller than the diameter of the gun barrel minus half the difference between the diameter of the gun barrel and the caliber. "Predominantly" in this context means that at least 60% of the contour must lie on this surface.

[0035] In a further embodiment, the shape of the caliber ring is selected such that, in the first position projected onto the longitudinal axis of the gun barrel, it comprises a first circular area or a ring shape having a first diameter that is larger than the diameter of the caliber plus half the difference between the diameters of the gun barrel and the caliber, and smaller than the diameter of the gun barrel. Furthermore, the shape of the caliber ring is selected such that, in the second position projected onto the longitudinal axis of the gun barrel, it comprises a second circular area having a second diameter that is smaller than the diameter of the caliber plus half the difference between the diameters of the gun barrel and the caliber, and greater than or equal to the diameter of the caliber of the weapon. In particular, 04.12.2025

[0036] 7 / 15

[0037] It is intended that the position of the centers of the two circular areas is different from each other in the projection.

[0038] In a further embodiment of the invention, the gun barrel has guide rails. This is common practice for gun barrels according to the prior art. The caliber ring runs beneath the lower guide rail. For pivoting the caliber ring, the guide rail has a type of bridge at this point, beneath which the caliber ring pivots. This provides a continuous guide rail in the area of ​​the caliber ring as well, thus enabling optimal and secure guidance of the weapon.

[0039] In a further embodiment of the invention, the caliber ring is in contact with the lateral guide rails in the second position, or the caliber ring is held in the end position by the movement device shortly before contact with the lateral guide rails. In the event of failure of the movement device or bending of the caliber ring, additional forces can be absorbed and introduced into the lateral guide rails through the direct contact, resulting in further stabilization.

[0040] In a further embodiment of the invention, the caliber ring has a contour such that the caliber ring fits snugly against the weapon from below in a semicircular shape on its underside. Furthermore, the caliber ring fits snugly against the weapon from above in two circular cutouts on its upper side.

[0041] In a further embodiment of the invention, the caliber ring, in its second position, creates an opening at its lowest point between the caliber ring and the wall of the gun barrel. While this reduces the effect of the caliber ring during ejection, it allows the fluid, in particular water or air, to drain away quickly enough after ejection, thus ventilating the gun barrel again. Only then does the gun barrel become accessible again from the pressure vessel.

[0042] In a further embodiment of the invention, the caliber ring consists of two wing halves connected centrally at the bottom. Manufacturing it from two wing halves has two advantages. 04.12.2025

[0043] 8 / 15

[0044] Advantages. Firstly, the manufacturing of the complex shape is simplified. Secondly, insertion into the weapon barrel under confined conditions is easier. Connection can preferably be achieved by screwing. In particular, a connecting element can also be used that joins the two wing halves and simultaneously establishes the connection to the movement mechanism.

[0045] In a further embodiment of the invention, a connection to the movement device is provided on the caliber ring, wherein the connection is movably mounted. In particular, the connection is angularly adjustable or rotatably mounted in the radial direction of the diameter of the gun barrel.

[0046] In a further embodiment of the invention, the gun barrel has sliding rails. The sliding rails are continuous even in the area of ​​the caliber ring.

[0047] In a further embodiment of the invention, the gun barrel has guide rails. The guide rails are interrupted in the area of ​​the caliber ring. In the second position, the caliber ring at least partially complements the guide rail. In particular, it can be provided that the shape of the caliber ring continues the shape of the guide rail in the second position. This serves less to guide the gun in this area, but rather to reduce the open cross-section, i.e., to reduce the amount of water flowing between the gun and the caliber ring. At the same time, this has an overall stabilizing effect. Therefore, there is preferably a gap between the gun during ejection and the part of the caliber ring that complements the guide rail; for example, the gap is 1 mm. In other words, the inner surface of the part of the caliber ring that complements the guide rail is recessed relative to the inner surface of the guide rail.

[0048] In a further embodiment of the invention, the caliber ring is shaped such that it receives a stabilizing force when the weapon is ejected, meaning it is not deformed or subjected to a significant restoring force. This is achieved by the caliber ring having a shape in the second position in which the velocity of the airflow around the caliber ring towards the weapon is greater than towards the wall of the weapon barrel. 04.12.2025

[0049] 9 / 15

[0050] In a further embodiment of the invention, the caliper ring is made of fiber-reinforced plastic. Due to its lower weight compared to a metal version, pivoting is easier, resulting in a simpler, more compact movement device. In a version consisting of two wing halves with a connecting element, the connecting element can, for example, be made of metal. In a further development of this embodiment, the caliper ring can have additional metallic reinforcements in the region of the axis of rotation or metallic reinforcements at least partially along the circumference of the caliper ring.

[0051] In a further embodiment of the invention, the caliber ring consists at least partially of plastic and at least partially of metal, and is manufactured in a single additive manufacturing step. An advantage of this manufacturing method is that metallic structures can be incorporated into the caliber ring at points of high structural stress, thus enabling targeted stiffening. It is also possible to encase the metallic structures in plastic to protect them from corrosion. Alternatively, instead of combined additive manufacturing, the metal structure can first be created and then encased in plastic.

[0052] The weapon barrel according to the invention is explained in more detail below with reference to an embodiment shown in the drawings.

[0053] Fig. 1 Longitudinal cross-section, first position

[0054] Fig. 2 Longitudinal cross-section, second position

[0055] Fig. 3 Cross-section, first position

[0056] Fig. 4 Cross-section, second position.

[0057] The figures show a gun barrel 10 with a hinged caliber ring 20. This is shown in the first position in Fig. 1 and Fig. 3, and in the second position in Fig. 2 and Fig. 4. 04.12.2025

[0058] 10 / 15

[0059] Fig. 1 and Fig. 2 show a longitudinal cross-section in the longitudinal direction of the gun barrel 10, Fig. 3 and Fig. 4 show a transverse cross-section perpendicular to the longitudinal direction of the gun barrel 10.

[0060] Guide rails 30 for guiding a weapon 50 are arranged in the gun barrel 10, as is customary. The lower guide rail 30 is supported, thus creating space for internal components, whereby the longitudinal axis of the weapon is positioned slightly above the longitudinal axis of the gun barrel.

[0061] In Fig. 1 in combination with Fig. 3, the caliber ring 20 is in the first position, so that it only minimally reduces the cross-section, as can be clearly seen in Fig. 3.

[0062] The hinged caliber ring can be folded from the first position shown in Figs. 1 and 3 to the second position shown in Figs. 2 and 4 by means of the movement device 40. For this purpose, the caliber ring 20 rotates about a horizontal axis of rotation 22, for example, by extending the movement device 40 hydraulically and forcing the rotation. As can be seen in Fig. 4, this largely closes the cross-section, leaving a small gap on the underside to allow the fluid, in particular water or air, to drain after ejection. For example, as can be seen in Fig. 2, in the second position the caliber ring 20 rests against the central guide rails 30 to dissipate forces during ejection. Additionally, the movement device 40 stabilizes the caliber ring 20 during ejection against the pressure generated by the ejection and thus against the forces acting on the caliber ring 20.

[0063] The shape of the caliber ring is chosen such that the cross-section in the first position is minimal, as shown in Fig. 3. At the same time, the curved edges of the caliber ring 20, as can be seen in Fig. 2, are curved so that they fit snugly against the weapon 50 (with a minimal gap), as can be seen in Fig. 4.

[0064] Reference sign

[0065] 10 gun barrels

[0066] 20 Caliber Ring 04.12.2025

[0067] 11 / 15

[0068] axis of rotation

[0069] Guide rail

[0070] Motion device

[0071] weapon

Claims

December 4, 2025 12 / 15 Patent claims 1. Weapon tube (10) with a hinged caliber ring (20), wherein the caliber ring (20) is movable from a first position to a second position, wherein in the second position the caliber ring (20) reduces the gap between the wall of the weapon tube (10) and the weapon (50) arranged in the weapon tube (10), wherein in the first position the caliber ring (20) rests against the wall of the weapon tube (10), characterized in that the caliber ring (20) is made in one piece, wherein the caliber ring (20) is pivotable about a horizontal axis of rotation (22) between the first position and the second position.

2. Gun tube (10) according to claim 1, characterized in that the caliber ring (20) is shifted further towards the inside of the boat at the lowest point in the first position and further towards the outside in the second position.

3. Weapon tube (10) according to one of the preceding claims, characterized in that the weapon tube (10) has a movement device (40) for moving the caliber ring (20) between the first position and the second position, wherein the movement device (40) is arranged below the position for the weapon (50).

4. Weapon tube (10) according to claim 3, characterized in that the movement device (40) is a hydraulic movement device (40).

5. Weapon tube (10) according to claim 4, characterized in that the movement device (40) has a hydraulic circuit and at least one limit switch, wherein the hydraulic circuit and the limit switch are connected in such a way that the limit switch is hydraulically activated only after the movement device (40) has been extended. 04.12.2025 13 / 15 6. Weapon tube (10) according to one of claims 4 to 5, characterized in that the movement device (40) is connected to a hydraulic on-board network or a manual pump.

7. Weapon tube (10) according to one of the preceding claims, characterized in that the caliber ring (20) in the first position has an annular cross-section transverse to the weapon tube (10), wherein the circle is not closed at the upper end.

8. Weapon tube (10) according to one of the preceding claims, characterized in that the weapon tube (10) has guide rails (30), wherein the caliber ring (20) runs under the lower guide rail (30).

9. Weapon tube (10) according to claim 8, characterized in that the caliber ring (20) is in contact with the lateral guide rails (30) in the second position.

10. Weapon barrel (10) according to one of the preceding claims, characterized in that the caliber ring (20) has a contour such that the caliber ring (20) fits snugly against the weapon (50) from below in a semicircular shape on the underside, wherein the caliber ring (20) fits snugly against the weapon (50) from above in two circular cutouts on the upper side.

11. Weapon tube (10) according to one of the preceding claims, characterized in that the caliber ring (20) in the second position at the lowest point releases an opening between the caliber ring (20) and the wall of the weapon tube (10).

12. Weapon tube (10) according to one of the preceding claims, characterized in that the caliber ring (20) consists of two wing halves connected centrally at the bottom.

13. Gun barrel (10) according to one of claims 1 to 11, characterized in that the caliber ring (20) consists of two wing halves connected centrally at the bottom via a connecting element. 04.12.2025 14 / 15 14. Weapon tube (10) according to one of the preceding claims, characterized in that the weapon tube (10) has sliding rails, wherein the sliding rails are continuous even in the area of ​​the caliber ring (20).

15. Weapon tube (10) according to one of claims 1 to 14, characterized in that the weapon tube (10) has sliding rails, wherein the sliding rails are interrupted in the area of ​​the caliber ring (20), wherein the caliber ring at least partially complements the sliding rail in the second position.

16. Weapon tube (10) according to one of the preceding claims, characterized in that the caliber ring (20) is made of fiber-reinforced plastic.

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