1. Field of the Invention
The present invention relates generally to buoyancy devices for vehicles, and more particularly is an armor-protected buoyancy module. One or more of the buoyancy modules are installed on tracked or wheeled military vehicles to provide the vehicles with the ability to float.
2. Description of the Prior Art
Military vehicles are sometimes called upon to ford inland waterways, either because of the absence of bridges, or because of the inadequacy of existing bridges to carry heavy military vehicles. Most wheeled and tracked vehicles are not inherently amphibious. Some designs for vehicles which were originally amphibious (e.g., Bradley, M113) have been modified with additional armor and therefore no longer have sufficient flotation for safe water crossings. Due to the not infrequent need for military vehicles to cross water, amphibious capabilities are very desirable. Military vehicles have previously been made amphibious by one of four methods; (a) inherent design, (b) use of an erectable swim curtain, (c) use of pontoon structures, or (d) addition of inflatable appendages.
The inherent design of vehicles such as the AAV7 (tracked amphibian for US Marine Corps), the BMP-1 (infantry squad carrier for former Soviet Union), the PT-76 (amphibious light tank for former Soviet Union), and the DUKW (2xc2xd ton truck for US Army and Marines) provided amphibious capability for these vehicles. However, in order to provide the amphibious capability, one or more of the following design tradeoffs were required: increasing overall size to provide sufficient water displacement (as in the case of the AAV7), adding undesirable front glacis angles (as with the BMP-1), utilizing ineffectively thin armor (PT-76), or sacrificing land mobility (DUKW). Due to these required design concessions, the land performance of vehicles designed to be amphibious has historically been compromised to some extent in exchange for their amphibious capabilities.
Erectable swim curtains were first tried on the xe2x80x9cDuplex Drivexe2x80x9d Sherman tanks used in the Normandy invasion. The xe2x80x9cDDxe2x80x9d kit consisted of an erectable upper frame connected to a rubberized canvas bellows whose bottom end was secured to the tank. The overall effect was similar to an accordion laid on its side. The DD modification had the disadvantage that the driver had no vision to the front. Additionally, the bellows was fragile, and subject to damage from either shell fragments or blast effect, as well as dynamic loading from wave impacts. Due to the fact that the bellows was not compartmentalized, damage to any portion of the curtain could result in flooding of the entire vehicle. Of an entire battalion fitted for the invasion, not a single tank made it to the beach.
Rigid pontoon kits have been tried by several countries. Disadvantages of such kits include:
a) Transport required to move the kit when it is not mounted. Use of such kits entails considerable logistic burden in forward areas.
b) Disclosure of operational intention by the presence of the kits in forward areas.
c) Time required to mount the kit.
d) Material handling equipment (cranes and jacks) required to mount the kit.
e) Ability to ingress and egress steep banks. In inland waters, the bow and stern of the pontoon kit may contact the bank and prevent forward progress. Additionally, currents tend to swing the vehicle around once either end is in contact with the bank.
f) Limitation of ground mobility before and immediately after the crossing. Turning radius and ground clearance are severely limited. Width of the vehicle may be a serious limitation in wooded assembly areas.
g) Time required to remove the kit after the crossing.
h) Transport, time, and specialized equipment required to recover the kit for reuse. If kits cannot be reused, a kit must be supplied for each vehicle in the crossing unit. New kits must be provided before a second crossing operation can be undertaken.
In general, pontoon kits are simply unsuitable for use by reconnaissance units, who habitually operate away from their parent organizations and are therefore separated from the logistical support inherently required for the use of pontoons. Unfortunately, these reconnaissance units are precisely the ones most likely to require amphibious capability.
Finally, U.S. military designers have most recently turned to the use of inflatable pontoon appendages. A kit for the M113 family of vehicles was tested in 1995. This kit consisted of rubberized cylindrical pontoons that attached to the sides and front of the vehicle. The pontoons were connected to the vehicle by a manifold fed by a centrifugal air compressor (modified engine turbocharger) which was powered by a gasoline engine. The compressor and manifold were required to inflate the pontoons and to provide makeup air to compensate for leaks. A principal shortcoming of the pontoon system is the logistical burden associated with transporting the pontoons, compressor, manifolding, and auxiliary gasoline engine when they are not in use. The deflated pontoons interfere with operation of the vehicle on land, so the kit must be fitted immediately before a swim operation and removed immediately thereafter.
Accordingly, it is an object of the present invention to provide a buoyancy additive device to provide amphibious capability to a vehicle that does not require modification of the basic design of a vehicle.
It is a further object of the present invention to provide a flotation aid device that does not impair the vision of the operators of a vehicle.
It is a still further object of the present invention to provide a flotation aid device that has armor protection of the buoyancy modules.
It is another object of the present invention to provide a flotation aid device that does not require independent transport.
The present invention is an armor-protected buoyancy module that is installed on tracked or wheeled vehicles to provide the vehicles with amphibious capability. The buoyancy modules are of such a size so that they can be lifted by two men without additional material handling equipment. The buoyancy modules are attached to fixed mounting devices that are mounted on the subject vehicle. Existing armor elements may be present to serve as the mounting devices for the buoyancy modules. The modules are hinged at a top side to swing open when they are deployed by pressurization, and latched at a bottom side to secure the modules when they are stowed. An armor shell provided for the buoyancy module protects it in both the deployed and stowed configurations.
An advantage of the present invention is that the buoyancy module can be used on nearly any vehicle for which amphibious capability is desired.
Another advantage of the present invention is that the armor protects the bellows, both when the device is deployed and when it is stowed.
A still further advantage of the present invention is that it does not require independent transport means.
Another advantage of the present invention is that the inherent compartmentalization of the modules ensures damage tolerance from enemy fire. A damaged module does not compromise the buoyancy of an adjoining module.
These and other objects and advantages of the present invention will become apparent to those skilled in the art in view of the description of the best presently known mode of carrying out the invention as described herein and as illustrated in the drawings.