GB1575044A

GB1575044A - Launching tube for a missile

Info

Publication number: GB1575044A
Application number: GB705077A
Authority: GB
Original assignee: Bofors AB
Current assignee: Saab Bofors AB
Priority date: 1977-02-18
Filing date: 1977-02-18
Publication date: 1980-09-17
Also published as: FR2381269B1; DE2707322C2; DE2707322A1; CH618507A5; FR2381269A1

Abstract

The launching casing holds a projectile and has a front cover (3) which is removed by the pressure wave which is produced in the launching casing as soon as the propulsion gases from the rocket motor of the projectile start to strike the rear cover (4) of the casing body (2). The casing furthermore contains means (5) for changing the further movement direction of the front cover in order that said cover moves along a path which differs from the launching direction of the projectile. In the case of such a casing, mechanical contact between said casing and the projectile can be avoided. <IMAGE>

Description

(54) A LAUNCHING TUBE FOR A MISSILE (71) We, AKTIEBOLAGET BOFORS of S-690 20 Bofors, Sweden, a Swedish jointstock company, acting under the laws of Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following state ment - The present invention relates to a lauching tube for a missile wherein a cover on the tube is arranged in such a way that mechanical contact between the missile and the cover is avoided when the missile is launched from the tube.

To avoid external influences on ammunition it is previously known to store ammunition in containers. If the container is to be used as a launching tube for some kind of rocket motor propelled projectile then the tube must be sealed at both ends. If the weapon is disposed ready for firing for some time then it is often necessary to provide the tube with seals to protect the projectile from rain and snow.

The seal at both ends of the launching tube are usually in the shape of covers and are removed at the instant of launch.

To minimize the time between sighting a target and firing it is necessary to remove the covers automatically. The most simple way to do this is to use the propellant gases from the rocket motor to blow away the rear cover and let the missile itself push away the front cover. Problems arise however when a missile with foldable wings, rudder or other easily damaged parts hits the front cover or parts of it.

Heretofore known cover devices which are pushed away by the missile itself are based either on the principle of frangible material which is broken by the missile itself or on the membrane principle in which the missile penetrates a thin membrane. Common to these previously known devices is the drawback that the missile comes into mechanical contact with the cover or parts of it and may be damaged. Covers of the membrane type also have the drawback that they do not resist pressure differences to any great extent.

The object of the present invention is to provide a launching tube which eliminates the above mentioned drawbacks.

In accordance with this invention therefore we provide a launching tube for a missile comprising a hollow launch tube, a rear cover member enclosing one end df said tube a front cover member detachably enclosing the opposite end of said tube and arranged to be separated from contact with said tube by means of a pressure wave generated in said tube by propellant gases from the missile hitting the rear cover member, and releasable means coupling the front cover member to the tube to cause the front cover member to move along a trajectory deviating from the launching direction of the missile as the front cover member separates from the tube.

The releasable means preferably comprises a hook which has one part pivotally secured to the central part of the cover and the other part removably attached to the wall of the launching tube.

An embodiment of the invention will be described in more detail with reference to the accompanying drawings, in which figure 1 is a view of a missile disposed in a launching tube with a sealing cover, figure 2 is a view showing the motion of the front cover relative to the launching tube after separation, figure 3a is a view of the front cover from below and figure 3b is a crosssectional view of the cover.

Referring now to the drawings there is illustrated in a schematic view a missile 1 disposed in a cylindrical launching tube 2, which is employed as a container for the missile during storage and transport. The launching tube 2 is provided with a front cover 3 and a rear cover 4 which enclose opposite ends of the tube and protect a missile in the tube from dust, rain and snow.

When the missile is ready for launching the rocket motor is provided with an ignition pulse and when the pressure in the motor has reached a certain level the nozzle plug is broken and propellant gases from the rocket motor flow out through the nozzle. When the propellent gases hit the rear cover 4 a pressure wave is established in the tubular space between the inner wall of the launching tube and the missile 1.

When the pressure wave reaches the front cover, energy is transferred from the pressure wave to the cover with the result that the cover 3 separates from the launching tube 2 and for a short time accelerates in the launching direction faster than the missile so that the cover gets a start on the missile As shown in figure 2, in the initial position the front cover 3 is connected with the launching tube 2 via a pivoted hook 5 so arranged that the cover changes its trajectory after separation from the tube. This change in trajectory continues until the hook 5 reaches a position at which it is released from the wall of the launching tube.

The cover then continues along its trajectory which deviates from the launching trajectory of the missile so that the missile 1 passes the cover 3 without coming into mechanical contact with it.

In figure 2 the cover 3 is illustrated in five different positions during its trajectory, which positions are indicated by A, B, C, D and E respectively. In its initial position A the front cover 3 provides an end seal for the launching tube 2. The cover in dudes a part 6 in the form of a circular disc which is in contact with the end surface of the tube and a tubular part 7 which extends into the tube 2 and has a diameter which is little less than the inner diameter of the tube 2. Between the cover 3 and the launching tube 2 sealing rings are arranged which rings are more fully described in connection with figure 3.The hook 5 that connects the cover 3 with the launching tube 2 has one part pivotally connected to the central part 8 of the cover so that the cover 3 after the release from the tube -per- forms a parallel motion out of the tube wand does not hit any part of the end of the tube. The other end of the hook is shaped as a claw and is releasably attached in a recess 9 in the wall of the tube. The clawshaped part is retained in the recess by a wall 10 so that the claw is not released from the recess until the hook has moved through a predetermined angle causing the cover to change its direction of motion. In the positions B and C the cover essentially follows a circular trajectory until the claw is released from the recess.The cover then continues along a trajectory that deviates from the trajectory of the launched missile, see the positions indicated by D and E.

The velocity of the front cover is an important parameter and the value depends on the weight of the cover and the strength of the pressure wave. The strength of the pressure wave depends on weight, tensile properties and geometrical properties of the rear cover 4. The weight and properties of the rear cover may be similar to the front cover.

Figures 3a and b show in more detail the underside and a cross-sectional view, respectively of the front cover. The discshaped part 6 of the front cover has a plane circular sealing surface in contact with the end surface of the tube and a sealing ring 12 disposed in a recess 13 in the end surface of the tube which ring seals axially to the cover as the cover is squeezed to the sealing ring by means of an end case (not shown). The cover is also sealed radially relative to the tube by means of a rubber ring 14 fixed by cement on the outer surface of the tubular part. The rubber ring serves as a seal when the weapon is ready for launching, on a base. The central part of the cover has a tubular part 8 with a smaller diameter and concentric with the tubular part 7.The hook 5 includes two legs 15, 16 which are pivoted on rivets 17, 18 mounted in opposite reinforced parts in the wall of the tubular part 8.

WHAT WE CLAIM IS:- 1. A launching tube for a missile comprising a hollow launch tube, a rear cover member enclosing one end of said tube, a front cover member detachably enclosing the opposite end of said tube and arranged to be separated from contact with said tube by means of a pressure wave generated in said tube by propellant gases from - the missile, hitting the rear cover member, and releasable means coupling the front cover member to the tube to cause the front cover member to move along a trajectory deviating from the launching direction of the missile as the front cover member separates from the tube.

2. A tube according to Claim 1, wherein the releasable means includes a hook having one part attached to the central part of the front cover member and another part releasably attached to a wall of the launching tube.

3. A tube according to Claim 2, where in the other part of the hook is shaped as

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. missile during storage and transport. The launching tube 2 is provided with a front cover 3 and a rear cover 4 which enclose opposite ends of the tube and protect a missile in the tube from dust, rain and snow. When the missile is ready for launching the rocket motor is provided with an ignition pulse and when the pressure in the motor has reached a certain level the nozzle plug is broken and propellant gases from the rocket motor flow out through the nozzle. When the propellent gases hit the rear cover 4 a pressure wave is established in the tubular space between the inner wall of the launching tube and the missile 1. When the pressure wave reaches the front cover, energy is transferred from the pressure wave to the cover with the result that the cover 3 separates from the launching tube 2 and for a short time accelerates in the launching direction faster than the missile so that the cover gets a start on the missile As shown in figure 2, in the initial position the front cover 3 is connected with the launching tube 2 via a pivoted hook 5 so arranged that the cover changes its trajectory after separation from the tube. This change in trajectory continues until the hook 5 reaches a position at which it is released from the wall of the launching tube. The cover then continues along its trajectory which deviates from the launching trajectory of the missile so that the missile 1 passes the cover 3 without coming into mechanical contact with it. In figure 2 the cover 3 is illustrated in five different positions during its trajectory, which positions are indicated by A, B, C, D and E respectively. In its initial position A the front cover 3 provides an end seal for the launching tube 2. The cover in dudes a part 6 in the form of a circular disc which is in contact with the end surface of the tube and a tubular part 7 which extends into the tube 2 and has a diameter which is little less than the inner diameter of the tube 2. Between the cover 3 and the launching tube 2 sealing rings are arranged which rings are more fully described in connection with figure 3.The hook 5 that connects the cover 3 with the launching tube 2 has one part pivotally connected to the central part 8 of the cover so that the cover 3 after the release from the tube -per- forms a parallel motion out of the tube wand does not hit any part of the end of the tube. The other end of the hook is shaped as a claw and is releasably attached in a recess 9 in the wall of the tube. The clawshaped part is retained in the recess by a wall 10 so that the claw is not released from the recess until the hook has moved through a predetermined angle causing the cover to change its direction of motion. In the positions B and C the cover essentially follows a circular trajectory until the claw is released from the recess.The cover then continues along a trajectory that deviates from the trajectory of the launched missile, see the positions indicated by D and E. The velocity of the front cover is an important parameter and the value depends on the weight of the cover and the strength of the pressure wave. The strength of the pressure wave depends on weight, tensile properties and geometrical properties of the rear cover 4. The weight and properties of the rear cover may be similar to the front cover. Figures 3a and b show in more detail the underside and a cross-sectional view, respectively of the front cover. The discshaped part 6 of the front cover has a plane circular sealing surface in contact with the end surface of the tube and a sealing ring 12 disposed in a recess 13 in the end surface of the tube which ring seals axially to the cover as the cover is squeezed to the sealing ring by means of an end case (not shown). The cover is also sealed radially relative to the tube by means of a rubber ring 14 fixed by cement on the outer surface of the tubular part. The rubber ring serves as a seal when the weapon is ready for launching, on a base. The central part of the cover has a tubular part 8 with a smaller diameter and concentric with the tubular part 7.The hook 5 includes two legs 15, 16 which are pivoted on rivets 17, 18 mounted in opposite reinforced parts in the wall of the tubular part 8. WHAT WE CLAIM IS:-

1. A launching tube for a missile comprising a hollow launch tube, a rear cover member enclosing one end of said tube, a front cover member detachably enclosing the opposite end of said tube and arranged to be separated from contact with said tube by means of a pressure wave generated in said tube by propellant gases from - the missile, hitting the rear cover member, and releasable means coupling the front cover member to the tube to cause the front cover member to move along a trajectory deviating from the launching direction of the missile as the front cover member separates from the tube.

a claw rotatably mounted in a recess in the wall of said tube so that on rotation of said hook through a predetermined angle, the hook is released from said recess.

4. A launching tube for a missile substantially as described herein with reference to the accompanying drawings.