Electrical connectors – Interrelated connectors relatively movable during use – Movement about axis
Reexamination Certificate
1999-07-26
2001-05-08
Sircus, Brian (Department: 2839)
Electrical connectors
Interrelated connectors relatively movable during use
Movement about axis
C439S201000
Reexamination Certificate
active
06227866
ABSTRACT:
BACKGROUND OF THE INVENTION
(1). Field of the Invention
The present invention relates generally to a rotary joint providing mechanical and electrical connection, and more particularly to a rotary joint between a rotating handling system or winch and a stationary structure.
(2) Description of the Prior Art
Current rotary joints used in handling arrays of hydrophones towed behind a vessel are found to be failing prematurely, i.e., failures have been observed after significantly shorter time periods than design life. Replacing failed rotary joints is costly and, in the case of a submarine towed array, replacement is made more difficult as the joint is located in the ballast tank of the submarine. The current rotary joints are seen to have a number of design problems.
The rotary joints contain pressurized insulating fluid within their cavities, tending to allow easier rotation of the shaft about the journal bearing of the joint. When the array is towed from a submarine at depth, the ballast tank becomes pressurized, putting external pressure on the joint, tending to collapse the joint and also increasing friction between the shaft and bearing. Thus, a pressure compensator is provided in the rotary joint to maintain the positive pressure within the joint cavity relative to the ballast tank. Current rotary joint pressure compensators consist of a neoprene bladder which becomes brittle and cracks after repeated temperature and pressure variations. The cracking allows seawater to infiltrate the rotary joint causing reduction in insulation resistance between the conductors. The towed array performance is thus degraded until at some point the seawater intrusion results in a complete electrical short. Also, the electrical contacts of current rotary joints are made of a material subject to flaking during use, allowing conductive material into the insulating fluid. As with seawater, this flaking leads to performance degradation and eventually to an electrical short.
In the rotary joints used in submarines, the present design makes high use of proprietary components and long lead items for manufacture which raises unit costs and extends fabrication times. Consequently, the inventory is kept at a minimum with resultant replacement delays when failures throughout the fleet exceed inventories. As noted previously, the location of the rotary joint in the ballast tank of submarines presents replacement difficulties. The weight and size of present rotary joints increase the difficulty. Further, there are presently four separate designs for the rotary joints used in navy vessels, thus further complicating inventory maintenance and replacement. in and not allowing quick replacement of units.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a rotary joint having a pressure compensator made of corrosion resistant material more suitable to a marine environment.
Another object of the present invention is to provide a rotary joint having electrical contacts which minimize flaking of the contacts into the insulating fluid within the towed array.
A further object of the present invention is to provide a rotary joint having electrical contacts with an extended life cycle.
Still another object of the present invention is to provide a rotary joint having a journal bearing made of nonconductive, commercially available material such that wear on the bearing does not result in introducing conductive material into the insulating fluid.
A still further object of the present invention is to provide a rotary joint fabricated of commercial, or off-the-shelf parts to reduce costs and minimize replacement times.
Yet another object of the present invention is to provide a universal rotary joint design of reduced size and weight which can be used on all navy vessels.
Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
In accordance with the present invention, a rotary joint is provided consisting of two main halves, a rotating half and a stationary half, fabricated of a titanium alloy to increase corrosion resistance in the marine environment and reduce the weight of the rotary joint by 50 percent compared to current designs. The rotating half has a universal mounting plate designed to be compatible with all current navy vessels. This plate attaches to the rotating stowage drum of the towed array handling system. The journal bearing of the new rotary joint is fabricated from a nonconductive material, so as to eliminate the possibility of introducing conductive particles into the insulating fluid within the towed array. An electrical connector mates with the towed array pendant cable and the inner rotating shaft has red brass contact rings to transmit the signals from the towed array to the stationary half of the rotary joint via stationary, spring loaded, red brass pins within the stationary half. The red brass rings and pins are less susceptible to flaking than current materials used. An electrical connector on the stationary half mates with the cable from the ship's internal systems. The stationary half of the rotary joint has an external housing mounted to a ship structure foundation. Again the mounting is universal to allow use of a single rotary joint design for all navy vessels. The pressure compensator has a dual spring design with a piston interposed between the two springs. The springs and piston are fabricated of corrosion resistant material, eliminating the neoprene bladder currently used along with its inherent problems. Readily available, commercial material has been used throughout the new rotary joint to lower costs and shorten fabrication lead times.
REFERENCES:
patent: 4880390 (1989-11-01), Brackmann et al.
patent: 4909741 (1990-03-01), Schasteen et al.
patent: 5931681 (1999-08-01), Thomassin et al.
Diodato Stephan J.
Williams Michael R.
Gauthier Robert W.
Lall Prithvic C.
McGowan Michael J.
Prasad Chandrika
Sircus Brian
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