Manipulator Apparatus For Gripping Submerged Objects

Abstract

A resilient, plate-like body member is secured to an articulated manipulator frame in position to be moved by the frame into a pressurized, gripping contact with the object to be manipulated. The body member carries a plurality of closely spaced suction cups which directly engage and grip the object and, to augment the gripping action as well as permit release of the suction grip of the cups, the body member is provided interiorly with a main hydraulic circuit extending in network fashion into relatively close proximity with each suction cup. A separate hydraulic conduit communicates the central portion of each cup with the hydraulic circuit and the circuit leads to a valve movable from a closed to an open position in which the hydraulic circuit as well as the cups which it serves are exposed to the sea water environment. The suction grip is achieved by pressing the body member into engagement with the object. Release of the object is achieved by opening the valve to admit environmental water which relieves the suction grip. A pump also may be coupled to the main hydraulic circuit through the valve to increase the gripping action. To accommodate irregularly shaped objects, the resilient body member can be made to conform by using a plurality of cells that can be expanded or contracted by pressurized fluid to produce a desired bend. To avoid the loss of suction from cups not in contact with the object, the cups each may be provided with an automatic valve having a balanced piston actuated by a pin only when the cup engages the object.

Description

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION

The present invention relates to manipulators for the handling and recovering of objects from the sea bottom and, in particular, to suction-type gripper members for securely engaging and manipulating these objects.

Manned and unmanned deep-sea submersibles presently are used for a variety of purposes included among which is the task of handling and recovering objects resting on the sea bottom. To accomplish this task, the submersibles are provided with manipulators which project outwardly and are provided with gripping arms frequently having the shape and articulation of a crab's claw. Although considerable success has been experienced with these manipulators, it nevertheless has been found that the contact between their hard polished surfaces and the object results in slippage which renders the recovery task far more difficult and time-consuming. Improvement of the gripping action of course can be achieved by increasing the frictional engagement of the manipulator and it is known that one way of improving the friction is provided by the use of suction cups which nature has implemented in the octopus. However, due particularly to the high hydrostatic pressures experienced at the depths in which the submersibles operate, it becomes quite difficult to free the object after the suction grip has been applied.

It therefore is a primary object of the present invention to provide a manipulator adapted for deep sea submersibles, the manipulator having a suction-type gripping action and further being provided with means assuring rapid relief of the suction when release of the object is desired.

Another object is to provide a manipulator of the type described in the foregoing object, the manipulator employing the water pressure of the sea-water environment to achieve the release.

Still another object is to provide a suction-type liner member for use with existing submersible manipulators.

A further object is to provide a novel manipulator utilizing a frame-supported resilient member to carry the suction cups, the resilient member being provided with means for varying its curvature in conformity with the curvature of the object to be gripped.

Yet another specific object is to provide a special suction cup for use with the manipulators.

These and other objects are achieved by utilizing a resilient, plate-like body member capable of being attached to a manipulator frame as a liner or of being secured as an independent plate member having its own reinforcement for achieving the strength and rigidity necessary to produce the gripping force. The resilient body member carries a plurality of closely spaced suction cups each of which has its central portion communicated with a main hydraulic circuit that leads to a valve which may be within the submersible or, if desired, can be remotely controlled from the submersible. Preferably, although not necessarily, a suction pump or other suitable low-pressure means, communicates with the main hydraulic circuit through the valve. When the manipulator is to be engaged with the object, its articulated frame can be moved to press the suction cups of the body member into tight contact with the object, the water in the suction cups then escaping from the sides of the cups and also escaping through holes or passages provided in the body member. During this initial engagement, the valve may be closed, although preferably the suction grip is improved by opening the valve and subjecting the suction cups to the low pressure produced by the vacuum pump or other low pressure means. When release of the object is desired, the valve is opened to admit sea water the pressure of which then is applied to the suction cups through the main hydraulic lines to relieve the suction. Opening of the valve to the sea water, of course, closes the pump circuit.

In one embodiment the body member is provided with its own reinforcement so as to function as an independent gripper rather than as a liner for existing manipulator frame. However, resiliency is retained and means also are provided to permit the resilient body member to conform to the curvature of the object being gripped. The means for producing the conformity most suitably includes a plurality of cells each coupled to a pressure line which exerts high or low pressures to expand or contract the cells. The cells are disposed near one or the other face of the body member of the plate-like body member so that the expansion or contraction reduces or expands this particular face to provide the desired curvature. Other features of the invention, such as a suction cup mechanism for preventing loss of suction when one of the cups is not engaged with the object, will be described subsequently.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated in the accompanying drawings of which

FIG. 1 diagrammatically illustrates a manipulator frame suitable for use in the present invention, the frame carrying a suction-type gripper member;

FIG. 2 is a diagrammatic illustration of one type of the suction-type gripper member suitable for use preferably as a liner to cover the clamping surfaces of the existing manipulators;

FIG. 2a is a top plan view of the gripper member shown in FIG. 2;

FIG. 3 is a cross section of FIG. 2 taken along lines 3--3 of FIG. 2;

FIG. 4 is another diagrammatic illustration of a suction-type gripper member especially adapted for use with a manipulator frame of the type shown in FIG. 1, this member utilizing expandable cells to permit the gripper member to conform to a curvature of the object to be gripped;

FIG. 5 is a view similar to FIG. 4 showing the cells in their expanded state;

FIG. 6 is a view similar to FIG. 4 showing another cellular arrangement capable of producing a desired curvature;

FIG. 7 is a view similar to FIG. 6 showing the cells of FIG. 6 in a contracted state; and

FIG. 8 is a sectional view also in diagrammatic form showing a special type of suction cup.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, the manipulator of FIG. 1 includes an elongate arm or column 1 which, as will be appreciated, extends outwardly from the skin or hull of a submersible, the column telescopically supporting a frame member 2 which can be of any configuration although, as shown, it includes primary support arms 3 and 4 coupled through joints to shorter support arms 6 and 7 which, in turn, carry a gripper member generally identified in FIG. 1 by numeral 8. The whole arrangement is articulated to the extent that reciprocation of members 3 and 4 relative to column 1 causes the gripper member to close about an object to be manipulated or to open and release it. As will be appreciated, the illustrated manipulator is intended to be exemplary only and, of course, a wide variety of configurations may be used depending upon the primary purpose which the manipulator is intended to fulfill.

The present invention principally is concerned with improving the frictional engagement of gripper member 8 and, as has been stated, the improvement essentially resides in the use of suction devices and the control of the suction of these devices. It also has been stated that the gripper member used for the manipulator either can be employed as a liner or existing grippers or as an independent member attached to a frame such as frame 2 of FIG. 1. When used as a liner, the gripper member can be formed in the manner illustrated in FIGS. 2, 2a and 3 in which it will be seen that the member includes a resilient plate-like body member 11 which can be secured along one face such as face 12, to the gripping surfaces of existing manipulators. The other face portion 13 of member 11 carries a plurality of closely spaced suction cups 14 which function in the usual manner to grip any object against which they are firmly pressed. Interiorly, body member 11 is formed with a hydraulic circuit extending as a passage 16 throughout the length of the frame. Preferably, the circuit is formed as a network to the extent that, in addition to the longitudinal passages, the circuit includes transverse passages 17 which intercommunicate with passage 16 as shown in FIG. 2a.

Each of the suction cups, in turn, is communicated with main hydraulic circuit 16 by a short passage or conduit 18 extending, as shown, from passage 16 exteriorly through the central portion of each of the cups. A valve 19 controls the fluid flow within hydraulic circuit 16 and, as shown, this valve is coupled to the resilient liner or plate by a conduit 20. Obviously, valve 19 either can be mounted interiorly of the submersible or, if desired, it can be mounted exteriorly with suitable provision for remote control. In the illustrated form of the invention valve 19 is a three-way valve adapted to communicate circuit 16 either with sea water through an inlet 21 or with a low pressure means, such as a vacuum pump 22 coupled to the valve by a conduit 23. Depending upon the purposes for which the manipulator apparatus is designed, the pump could be replaced by a low pressure tank such as an atmospheric chamber or by an evacuating piston. Again, it will be understood that the apparatus of the present invention is illustrated in a simple, diagrammatic manner and that the physical location of the members, as well as the design of each member, becomes a matter of choice depending upon existing circumstances.

Operation of the apparatus illustrated in FIGS. 1-3 commences by moving the submersible which carries column 1 into proximity with the object to be manipulated or recovered. Frame 2 of the manipulator then is driven in any appropriate manner to produce a closing movement of gripper member 8 about the object. Assuming for present purposes that resilient plate 11 is employed as a liner for gripper member 8, the closing movement of gripper causes suction cups 14 to press against the object to produce a firm suction grip. During this operation, valve 19 is closed both to sea water and the pump. Obviously, water must escape from the interior of cups 14 as the cups are being pressed into engagement with the object and to facilitate the escape, plate 11 can be provided with openings or passages 24 in the manner shown in FIGS. 2a and 3. The escape of the water from cups 14 is facilitated since the water can pass through openings 24 which, as shown, extend through or perforate the gripper member. A firm grip can be produced without the use of a pump or other lower pressure means. However, the use of the pump augments the grip and this is recommended at least for certain applications. Its function is conventional to the extent that its use produces a low pressure side for cups 14. The low pressure combined with the high hydrostatic pressure of the water environment is capable of achieving a very firm gripping action. When the pump is used, the valve is rotated to communicate conduits 20 and 23 with the main hydraulic circuit.

The achievement of the gripping action is a significant feature of the present invention but it also presents some difficulty when it is desired to relieve the pressure and release the object from the manipulator. Thus, the manner in which the high hydrostatic pressure acting on the suction cups is overcome to achieve the release is an important feature of the invention. Briefly, release of the object is accomplished by rotating valve 19 so as to communicate hydraulic circuit 16 with the external sea water environment admitted through inlet 21. The sea water pressure then is transmitted through the hydraulic circuit and passages 18 to cups 14 to balance the hydrostatic pressure and permit the object to readily be released.

FIGS. 4 and 5 provide another embodiment incorporating two additional, although related, features. First, it is to be noted that body member 11 of this embodiment is formed with a flexible reinforcement member 26 which may be a loose metallic cloth, a chain mat or an arrangement of rigid interlocked plates. Such a reinforcement of plate member 11 permits the plate to be used as an independent gripper member as contrasted with its use as a liner. Thus, referring to FIG. 1, the embodiment of FIG. 4, instead of being used as a liner for a metal gripping member such as gripping member 8, in effect is substituted in its entirety for the gripping member so that it is attached directly to legs 6 and 7 of the manipulator frame. Most suitably, these legs of the frame are attached directly to reinforcing member 26.

FIGS. 4 and 5 also show a series of longitudinally spaced cells 27 intercommunicated by a passage 28 one end of which is communicated with a source of fluid pressure which, in practice, can be provided by pump 22, although, if desired, a separate pump or equivalent mechanism can be utilized. The purpose of the cellular structure is to provide a gripper member capable of conforming to the curvature of an object to be gripped. A desired curvature can be produced by applying fluid pressure to fill and expand cells 27 as the suction cups are being evacuated through hydraulic circuit 16 and, since cells 27 are disposed in relatively close proximity to outer face 12 of resilient body member 11, expansion of the cells, as shown in FIG. 5, increases the length of this outer face and produces the curvature shown in FIG. 5.

FIGS. 6 and 7 is an alternative stricture employing the same principles as those described with respect to FIGS. 4 and 5. However, in FIGS. 6 and 7, cells 27 are disposed in proximity to face 13 of resilient body member 11 and instead of employing a separate passage 28, the structure employs the suction of pump 22 acting through hydraulic circuit 16 to cause the cells to contract in the manner shown in FIG. 7.

It also may be desirable to avoid a loss of suction from the suction cups which, due to surface irregularities, are not in contact with the object. As shown in FIG. 8, the suction cups may be provided with an automatic valve having a balanced piston 31 spring pressed into a seating engagement with a valve seat provided by a cylinder 32. Cylinder 32, in turn, is coupled to hydraulic circuit 16 by a conduit 33. To permit piston 31 to be unseated, the piston is provided with an extension pin 34 projecting outwardly through the central portion of each cup 14 a sufficient distance to cause the pin to engage the object as the cup is moved into contact with it. Consequently, as long as the cup does not engage the object, the piston remains seated to prevent suction loss through the cup. Conversely, as the cup is forced into contact with the object, the piston is physically forced rearwardly to communicate the cup with the low pressure of the pump.

The advantages of the present invention should be apparent. First, it permits the achievement of a firm suction grip to essentially eliminate slippage. Secondly, it provides a simple but effective manner of relieving the gripping pressure when it is desired to release the object. Other distinct advantages are provided by the ability of the gripper to conform to curvatures or irregularities, as well as the ability of the gripper members to prevent loss of suction pressure when they are not physically engaged with the object.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

Claims

I claim

1. Manipulator apparatus for gripping submerged objects comprising:

an articulated gripper arm frame member,

a resilient plate-like body member carried by said frame member,

a plurality of closely-spaced rubber-light suction means carried by said body member for directly engaging the object to be manipulated,

a main hydraulic circuit formed within the body member in proximity with each suction cup,

a separate hydraulic conduit communicating the central portion of each cup with said hydraulic circuit,

conduit means communicating said main circuit with the water environment of said apparatus,

a valve disposed in said conduit means,

a plurality of longitudinally-spaced cells formed within the body member near one of its face surfaces, and

means for applying pressure to said cells whereby the shape of the cells is varied for producing a curvature of body member,

said suction means being formed for exerting a suction grip on said object when pressed into engagement with it and said valve being openable to admit environmental water for relieving said suction grip to permit release of the object.

2. The apparatus of claim 1 further including low pressure means communicated through said valve with said main hydraulic circuit for increasing the gripping force of said suction means.

3. The apparatus of claim 2 wherein said cell pressure means expands said cells.

4. The apparatus of claim 2 wherein said cell pressure means contracts said cells.

5. The apparatus of claim 2 wherein said cell pressure means is a pump and the pump communicates with said cells through said main hydraulic circuit.