1. Field of the Invention
The field of this invention relates to systems for deploying payloads from vessels, e.g. submarines, and in particular, systems for launching stores (e.g. torpedoes) from submarines.
2. Summary of the Prior Art
Conventional torpedo launch systems utilise fluid pressure to force a torpedo from a torpedo launch tube.
An example of a known torpedo launch system is described in European Patent No. EP 0526831 B. The system includes a torpedo launch tube, in which a torpedo is located prior to launch. A piston tube is provided adjacent the torpedo launch tube, the piston tube having a piston therein which is arranged to slide along the piston tube upon the application of fluid pressure (from compressed air). The piston tube includes a slot through which a projection of the piston extends. The piston projection is arranged to engage the torpedo such that, when the piston slides along the piston tube, the piston projection pushes the torpedo out of the torpedo tube.
However, problems arise with leakage of compressed air from the piston tube, through the slot. Leakage of compressed air reduces the fluid pressure in the piston tube, and thus the force at which the piston is slid along the piston tube. In an attempt to overcome this problem, a tongue seal is provided along the slot. However, providing a perfect seal along the entire length of the slot, whilst still permitting the piston projection to travel along the slot, is virtually impossible.
European Patent No. EP 0295600 B describes a conveyor device for loading and unloading torpedoes in a torpedo tube. The device includes a piston fixed through a piston rod to the torpedo tube, and a cylinder displaceable relative to the piston. A slide, on which a loading platform for an object is attachable, is mounted on the exterior of the cylinder and is driven, during movement of the cylinder relative to the piston, via a cable line. The cable line is located outside the cylinder, has ends securely connected to the torpedo tube, and runs over deflecting rollers in such a way that, during a cylinder stroke, the slide also moves along the cylinder. With this arrangement, the slide covers a greater distance than the cylinder relative to the piston, during a cylinder stroke.