US3550386A - Underwater vehicle - Google Patents

Description

Dec. 29, 970 H. A. BALLINGER 3,550,386

UNDERWATER VEHICLE Filed March 28, 1968 2 Sheets-Sheet 1 1970 H. A. BALLINGER UNDERWATER VEHICLE 2 Sheets-Sheet a Filed March 28, 1968 United States Patent 3,550,386 UNDERWATER VEHICLE Hugh Anthony Ballinger, Abingdon, England, assignor to United Kingdom Atomic Energy Authority, London, England Filed Mar. 28, 1968, Ser. No. 716,730 Claims priority, application Great Britain, Mar. 31, 1967, 14,9 75/ 67 lint. Cl. B25j 3/00; B63c 11/00; 363g 8/00 U.S. C]. 61-69 8 Claims ABSTRACT OF THE DISCLOSURE An underwater vehicle comprising a free flooding streamlined body shell attached to a control cable, one or more retractable manipulator arms mounted on a rotatable turret within the body, propulsion means and manoeuvring control means, and a retractable limb.

This invention relates to remotely controlled devices and is particularly concerned with devices for undersea use.

The requirement for remotely controlled marine devices arises for exploratory purposes, seat bottom sampling and the inspection and recovery of objects on the sea bed.

According to the present invention an underwater vehicle comprises a free flooding streamlined body shell attached to a control cable, one or more retractable manipulator arms mounted on a rotatable turret within the body, propulsion means and manoeuvring control means, and a retractable limb.

Preferably the limb is provided with suction pad at its free end, and the propulsion, manoeuvring control, and retractable limb are powered by a low-pressure water moving pump.

Preferably the limb is mounted on a rotatable sponson and the sponson is provided with a water jet discharge opening forming part of the said manoeuvring control means. The water jet discharge opening or openings may be arranged axially and/or radially with respect to the aXis of rotation of the sponson if desired.

FIG. 1 is a diagrammatic drawing showing an underwater vehicle constructed in accordance with the features of the present invention.

FIG. 2 is an enlarged schematic view of a portion of FIG. 1 showing the limb in the retracted position, showing the foot pad in cross-section and showing the fluid lines schematically.

Referring to the drawings accompanying the complete specification the vehicle comprises a streamlined fibre glass body shell 1 formed on an internal tubular steel frame and attached by a cable stirrup 2 at the end of a control cable 3. The body is provided with guide vanes 4 which surround the main propulsion jet apertures 5 at the rear of the vehicle. A retractable pod 6, positioned centrally at the front end of the body, houses a television camera unit. One of a pair of retractable hydraulically operated manipulator arms 7 is housed in a rotatable turret located within the body on each side of the pod 6. Search light and television camera lights (not shown) are also located in faired housings on the body.

The body is provided with four retractable telescopic limbs 9 each limb being mounted on a rotatable sponson 10 rotatable about axis 23 attached to the sides of the body. Each limb terminates in a foot portion 11 and the foot is provided with a plurality of suction pads 24, each pad having a limiting orifice 25 and communicating via a central duct 26 in the limb with a low pressure sea water pump 12 through limb 9 and line 27 located within the body shell.

The pump 12 provides common power to the main propulsion thruster jets 5 at the rear of the vehicle and to manoeuvring control thruster jets located on the sponsons 10. Each sponson carries two thruster jets, a central outwardly directed jet 13 and a radially directed jet 14. Pump 12 is connected to 13 through line 21 and to 14 through line 22. The pump 12 is preferably duplicated, the two pumps being used in parallel for main drive and arranged such that either pump can be switched to supply the ancillaries. Valves 28 regulating the sea water flow to the ancillaries are of the clear flow diaphragm type-operated by fluid logic circuits. The hydraulics for the said fiuid logic circuits and that of the manipulator employ precision parts and are not operated by sea water.

The body includes buoyancy tanks 15 and fore and aft ballast tanks 16 are fitted to permit trim adjustment.

The vehicle is controlled remotely from a ship borne caravan unit via the control cable 3. An operator is provided with a control console which includes a screen showing a television picture of the working environment.

PRINCIPLE OF OPERATION A reasonable sized vehicle for marine use is approximately of 2 cubic yards displacement with a weight of 1.5 tons in air. Such a vehicle can be launched and retrieved by the cargo boom or conventional hoist 0n the average ship and does not demand the capital investment of special tender vessels.

For good diving performance the vehicle should be able to orientate itself into an attitude in which its formdrag is a minimum. In this position it should preferably be able to exert the full driving power of main propulsive unit of the vehicle.

The provision of a cable stirrup overcomes the disturbing torques of a directly fixed cable, the stirrup (a) permits the vehicle to dive vertically and quickly under power, to a prescribed depth, (b) reduces the disturbing torque on the vehicle when the latter is swimming in a horizontal search mode, (c) aids recovery of the vehicle in the case of an all-systems-failure by allowing the device to reorientate to a minimum drag position and so reduce recovery strain on the cable. If desired the cable may be used to produce a fast powered-recovery of the vehicle, in which the vehicle fiys up the track of the recovered cable.

When the vehicle is approaching an underwater obstacle or workpiece it is necessary to avoid mutual damage and the vehicle employs the front limbs as buffers as follows:

The sponsons holding the retracted two front-limbs are turned to a forward-facing position. The limbs are extended by inflating them with sea water from a low pressure bleed-off 30 from the main. pump outlet through line 27. In collision the limbs will act as buffers ejecting the contents through a displacement-controlled orifice 31,

of the type used on conventional hydraulic buffers. A feature of this principle is the built-in velocity-term which permits the buffer to cope with a variety of different approach speeds, for a vehicle of a given mass.

Having approached the object the vehicle may be anchored using the suction foot pads. It will be appreciated that, before buffer stopping, and with the limbs in their forward orientated retracted position, the limbs can be extended by a flow of water into the limbs resulting from the pressure drop across the central orifices in the foot-suction pads. If these limbs are used to buffer the vehicle there is some ejection through the suction pad orifices 25 but the main momentum of water escape is in the opposite direction, through the main displacementlimiting orifice 31 in each limb. When the vehicle stops,'

the momentum of main water flow and a suitably timed reversal to the suction of the main pump, locks the foot suction pads 11 on to the object: and even a modest pres sure differential of say 15 p.s.i. transferred from the limiting orifice 31 to the suction pads, will produce on a foot of 1 sq. ft area, an anchoring or grappling force of approximately one ton.

When the vehicle has buffered and locked on to the workpiece, continued suction in the legs, acting on their reduced cross-sectional area, produces a force which gently pulls the vehicle into close contact.

This latter mentioned force could be opposed if need be, by adding a facility to prevent the limbs retracting or by reversing the jet direction of the main thruster. It will be appreciated that the above actions have so far been performed by the active elements of only an on/off drive of the limb sponsons to forward limit stops and the changeover of flow in the limbs. Of special significance is that the high powered anchoring or grappling force can simply be released by reversing the flow from the pump; it also has the failure-to-safety feature of release, if the pumps fail. After the suction pads have been released and the vehicle has pushed itself clear by reextending its limbs, the limbs can be retracted back into their sponsons by reversing the flow again.

By adding a second pair of limbs in the aft sponsons, the vehiclehaving clamped onto the object with two limbs-has the ability to swing round and anchor one, or both, of the after pair of limbs onto the object. The force to achieve the swing motion of the vehicle is obtained from the manoeuvring jets which are located on, and rotate with, the after limb sponsons. This facility permits the vehicle to hang on to an object in any position. The requirement for operating in an inverted position, for example, could be derived from a need for inspection or work on the underside of floating dry docks, very large tankers, or stable floating platforms such as are used for oil drilling in deep water.

For operations on a softer section of the sea bed, the feet may be fitted with detachable Penman type mud shoes. The manoeuvring jets in the rotatable sponsons draw clean water from an intake in the body of the vehicle and the reaction of these jets may be used to hold the vehicle down in position. Should the feet stick in the mud they could be freed one at a time by jerking against the inertia of the vehicle. As a limb is freed, the sponson carrying that limb may be rotated so as to direct its manoeuvring jet to wash clear the adjacent foot.

One possible application of the ability to operate on soft sections of the sea bed is to carry out systematic sample coring. The vehicle could inject a core tube into the sediment then pull out the core tube by raising itself on its limbsdetach and float the packaged sample back to the surface while it proceeded to the next sample point. For the examination of rock out-crops for commercial ores, the random results of a dredge can be replaced by a geologist choosing the exact location and the size of samples he wants. These can be chipped out, labelled and deposited in a collection basket by the manipulators.

For occasions when the object to be manipulated is at mid-depth, or is too small or delicate to be grappled, a hovering ability is provided by the use of the eight manouvring jet thrusters 13 and 14. When the limbs are retracted the sponsons can be lined up so as to bring the radially directed jet thrusters 14 into fore and aft opposition. Operation of all the jets 13 and 14 during a hovering phase, provides a stiffened resistance to relative drift. Current-created drift in horizontal planes can be balanced by partly closing a pair of the jet thrusters 13. For correction in the vertical plane, pairs of sponsons are rotated together to angle the opposing jet pairs slightly from the horizontal. The use of the jet-opposing principle, saves the time required to make a complete movement through 180, for small corrections of drift, in the vertical plane. To make corrections for orientation of heading (i.e. rotation about a vertical axis) the jet thrusters 13 in the centre of each sponson are throttled in diagonally opposite pairs.

Varying the operation of the jet thrusters mounted on the sponsons can duplicate the above mentioned orientation of heading and also produce roll and pitch movements, however stabilisation for the pitch movements can be reasonably left to a good centre of gravity configuration and a pre-adjusted fore and aft trim. The radial jet thrusters 14 on the sponsons may be used to counter balance short-term disturbances due to the manipulators being extended when in the hover position. During this operation the control of drift in the fore and aft direction is transferred to the main propulsion jet thrusters.

It will be apparent that use of a marine remotely controlled vehicle is advantageous in the ease by which the vehicle can carry out systematic seat bottom sampling, for example by using the ship to tow the cable of the vehicle, and giving via the ships echo sounder a forecast of the bottom level to the operator, a large search area can be covered in a short time. Additionally the use of the vehicle does not require the waiting to resurface delay of other methods, in order to present a full report of what has been seen and done.

The vehicle has the ability to Work around the clock, by using relays of operators, and may be risked in conditions of turbulent water and poor visibility where the hazard to men as divers, or as crew in conventional submersibles is too high. Using a grappling or anchoring facility, there is the potential ability to work in a tideway. The vehicle may also operate through a bad- Weather period on the surface, by using the technique of attaching a floating hose to the surface end of its cable and so reduce the coupling of the cable with the wave motion of the ship.

In the rescue role--for a marine disaster of national importance, the vehicle is light enough to be air freighted to the scene. Once at the site it is adaptable to almost any ship which is available.

I claim:

1. An underwater vehicle comprising a free flooding streamlined body shell attached to a control cable, propulsion means for propelling the vehicle, one or more manipulator arms mounted on the vehicle for retraction into said body, a plurality of rotatable sponsons on the body, means to rotate each sponson, a telescopically adjustable limb mounted on each of said sponsons, and manoeuvring control means comprising a water jet discharge opening provided on each sponson and means to discharge water from the opening.

2. A vehicle according to claim 1 wherein the control cable is attached to the vehicle by a stirrup member pivotally connected to the body shell such that the vehicle is capable of unrestricted rotation about the pivotal axis of the stirrup member.

3. A vehicle as claimed in claim 1 provided with a retractable pod housing a television camera.

4. A vehicle as claimed in claim 1, wherein the propulsion means, manoeuvring control means, and said retractable limb are powered by a low pressure water References Cited moving PumP- UNITED STATES PATENTS 5. A vehicle as claimed in claim 1 wherein said limb 728 031 5/1903 Sinclair 61 69 is provided with a suction pad at its free end. 1 3O4012 5/1919 61 69 6. A vehicle as claimed in 1 wherein water 5 bi Jr discharge opening extends axially with respect to the 3 15 123 11 19 4 Froelich 4, 1 axis of rotation of said sponson. 3,165,899 1/1965 Shatto, Jr. 61-69 7. A vehicle as claimed in claim 1 wherein said dis- 3,176,648 4/1965 Cavero 114--16X charge opening extends radially with respect to the axis of rotation of said sponson.

8. A vehicle as claimed in claim 1 wherein said pro- US, l. XR' pulsion means employs water jets. 114-16; 214--1 l0 JACOB SHAPIRO, Primary Examiner

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