US3194326A - Sonic tool for ocean floor coring - Google Patents

Description

July 13, 1965 A. e. BODINE, JR

SONIC TOOL FOR OCEAN FLOOR CORING Filed Aug. 28, 1962 INVENTOR. ALBERT BODINE JR. BYQZWZ% ATTORNEY United States Patent 3,194,326 SONl C T001, 1 0R @CEAN FLUOR CURKNG Albert G. Bodine, .l'ru, Los Augeles, Calif. (7877 Woodley Ave, Van Nuys, Calif.) Filed Aug. 28, 1962, Ser. No. 219,906 2 flairns. (Cl. 175- 56) This invention relates generally to the art of soil coring or sample taking, and deals more particularly with methods and apparatus for taking cores from the ocean floor by use of improved sonic coring equipment especially contrived for the purpose.

This application is .a continuationain-part of my prior application entitled Sonic Method and Apparatus for Extruding Flowable Materials, Serial No. 756,382, filed August 21, 1958, and deals with improvements upon the subject matter of said application and is concerned especially with problems peculiar to ocean floor coring, particularly at substantial depths under water.

This application is also a continuation-in-par-t ofcopending patent application Serial No. 710,956, filed January 24, 1958, now Patent No. 3,054,463, which latter was a continuation-in-pa'rt of earlier patent application Serial No. 644,774, filed March 8, 1957, now Patent No. 2,975,846. In addition, said applications No. 756,382, No. 644,774, and No. 710,956 were also copending with patent application Serial No. 611,131, now Patent No. 2,903,242.

The invention employs a certain sonically vibratory equipment of a general nature first disclosed in my Patent No. 2,554,005, issued May 22, 195 1, and entitled Earth Boring Apparatus. However, instead of the drill bit used in said eart-h boring apparatus, a coring tube is employed, as in my aforementioned application Serial No. 756,382; and instead of the chipping and fragmentation action characteristic of the earth boring apparatus, a core is taken by an extrusion type of process dependent upon acoustic coupling of the core tube to the formation from which the core is to be taken, and a soil fiuidization effect obtained under the conditions of the invention which facilitate the severing of the core and its entry into the core tube, as fully described in said parent application, which is incorporated herein by this reference.

An object of the present invention is the provision of a core taking system of a sonic nature which is ideally adapted and suited for operation in the ocean floor at very considerable depths under water.

A problem in deep water ocean floor coring is maintenance of the vertical orientation of the core tube during the operation, and a corresponding object of the invention is the provision of a sonic type of ocean floor coring apparatus which has an inherent tendency toward vertical orientation.

Another object of the invention is the provision of a sonic coring apparatus, especially adapted for underwater usage, and including a self-contained power source.

The invention is directed, particularly to the retrieving of cores from underwater earthen strata at substantial distance below the water surface, and is intended primarily for use in ocean floor coring. The invention is useful in oil exploration, marine organism study, re-

to vibrate in a longitudinal sonic standing wave mode. The sonic wave generator means is enclosed within the housing structure of a power unit, including an electric motor for driving the wave generator, and self-contained storage batteries for supply of electric energy to the motor. The housing structure of the power unit is lowered into the water on a flexible suspension cable, and guided by this suspension cable is an electrical conductor leading from suitable switching means above the water down to a relay for controlling flow of electric energy from the storage batteries to the electric motor.

The longitudinal vibratory standing wave pattern set up in the described elastic stern causes it to elastically elongate and contract, and by allowing weight to be imposed on the stem to an extent such as will result in pressure of the vibratory lower edge of the core tube on the formation during at least the half cycles of elastic elongation, the core tube works its way rapidly down into the formation of the ocean floor.

The longitudinal standing wave pattern in the stem and in the core tube portion thereof results in a tendency for the stem to maintain an upright position during penetration, for reasons that can best be set forth following a more detailed explanation of the apparatus.

A feature of unique advantage is the use of a simple storage battery power source, located within the housing of the power unit. This is made possible because of the nature of the sonic wave generator used in the system, and of its acoustic form of coupling to the stem. If the vibratory stem should stall, the motor driven part of such wave generator continues to operate freely. Thus the 1 motor cannot be stalled, and danger of an effective short circuit of the batteries from stalling of the vibratory stem is avoided.

Other objects and features of the invention will appear in the course of the following detailed description of an illustrative embodiment thereof, reference for this purpose being had to the accompanying drawings, in which:

FIG. 1 is a side elevational view of the ocean floor coring apparatus of the invention;

FIG. 2 shows the apparatus of FIG. 1, to larger scale, in longitudinal section, the section line through the vibration generator being taken on the broken line as indicated by the arrows 2-2 in FIG. 3;

FIG. 3 is a section taken on line 33 of FIG. 2:

FIG. 4 is a section of the vibration generator, taken in accordance with the line 4-4 of FIG. 2, with the generator rotors and driveshafts in a different position; and

FIG. 5 is a standing wave diagram showing the amplitude of vibratory motion of the resonant rod and core tube of the apparatus. FIG. 5 is drawn alongside the resonant rod and core tube of FIG. 2, and by projecting horizontally across, the width of the standing wave diagram indicates the amplitude of vibratory motion of the resonant rod and core tube at every point therealong. In the drawings, numeral 10 designates genarally a housing for the power unit and sonic wave generator, adapted for suspension, underwater, close to the doom floor, and furnished with a suitable suspension cable 11 for that purpose. Apparatus of conventional nature, carried by a boat or barge, and not shown herein, will be understood to be provided for paying out the cable, suspending in desired position, and reeling it in. A sonic wave generator, generally designated by numeral 12, and which comprises a special form of mechanical vibrator,

is mounted inside housing 10 on the upper end of a vertical rod 13, composed of a good elastic material such as steel, and which projects downwardly through the bottoni of housing 10. Screw-coupled to the lower end of this rod 13, as at 14, is the core tube 15, shown in this case to be made up of two tubing sections 15a and 15b coupled together by a screw joint at 16. The rod 13 and core tube 15 together make up an elastic, vertically oriented stem 17. Broadly considered, this stem might be tubular for its entire length, but a requirement is that at least a lower section of the stem be tubular, so as to form a core tube. The member designated generally by the reference numeral 17 may be called may be called the stem, or the core-tube stern.

Considering the housing 16 in more particular, it will be seen to comprise a tub 2t furnished with a cover 21, and with a battery pan or tray 22. These members 2 3, 21 and 22 have meeting flanges connected by suitable fastening means as at 24. On the bottom of tub 2% is a base plate 26 supporting an electric drive motor 27, a gear box 23, and the aforementioned sonic wave generator 12. Engaging the bottom of tub 2%) is the mounting flange 3d of a sleeve 31 which surrounds rod 13 and extends downwardly therearound to the mid-portion of the rod. Above the mid-section of rod 13, the sleeve 31 is annularly spaced therefrom but at the mid-section, the sleeve 31 is formed with an internally reduced portion 32 which has a shrink fit onto rod 13. As clearly shown in FIG. 2, the bottom wall of tub 2t and the base plate 26 are centrally apertured to pass the rod with annular clearance, as indicated at 34.

The aforementioned suspension cable 11 is connected to a suitable eye 38 which in turn carries a suspension means generally designated by the numeral 39, and which includes a base flange 4t) engaging housing cover 21. Tie rods 41 extend through the base flange 4% of suspension device 39, and through cover 21, tray 22, base plate 26, the bottom of the tub, and the mounting flange 30 of sleeve 31, and suitable nuts 42 threaded on the ends of these tie rods hold the various components of the housing, the suspension device 39 and the sleeve 31 in proper assembly.

A plurality of storage batteries 44 are mounted on the aforementioned tray 21, on base plate 26, and on racks such as 45, and these are interconnected with one another and with electric motor 27 for powering of the latter. They are also so selectively disposed within the housing as to cooperate with the electric motor, the gear box and the wave generator to achieve a balanced distribution of weight, so that the apparatus as a whole tends to hang vertically from cable 11. A relay 47 is preferably interposed between the battery supply cable and the electric motor, being controlled by a circuit conductor 48 lead upwardly through the tub cover and suspension device mounting flange 30 through a suitable grommet 49, whence it is tied to or wrapped around the suspension cable 11 to guide it to the ship or barge from which the apparatus is suspended. A control switch at this abovewater location permits control of power from the batteries to the electric motor 27 through the relay 47. Since such circuitry is well understood by those skilled in the art, no detailed disclosure thereof is deemed necessary herein.

The uper extremity of rod 13 is formed with a T-head 50. It will be understood that this T-head is perpendicular to the paper in the aspect of FIG. 2, so that one end of one leg thereof appears in elevation in said figure. Mounted rigidly onto this T-head 50 is the housing of the aforementioned sonic wave generator 12. The generator 12 is shown somewhat diagrammatically, as being of a preferred type first disclosed in my copending application Serial No. 131,385, filed March 21, 1962, and entitled Vibration Generator for Resonant Loads and Sonic Systems Embodying Same. The housing of the generator comprises an intermediate hollow body member or block 55, and two end plates 56 and 57.

Block 55 has two cylindric raceway bores 58, spaced horizontally from one another, and each contains an inertia rotor or rotor mass generally designated by reference numeral 60. Each such rotor 63 embodies an inertia roller 61, of somewhat less diameter than the corresponding raceway bore 53, and which is rotatably mounted on an axle 62 projecting axially from the hub portion of a spur gear 64, whose pitch circle is substantially of the same diameter as roller till. Gear 64 meshes with an internal gear 65 formed or mounted within housing body 55 concentrically with the corresponding raceway bore, and whose pitch circle is substantially of the same diameter as said bore.

Each rotor 66 is designed to move in an orbital path about its raceway bore 58 as a guide, with gear 64 in mesh with ring gear 65, and with inertia roller er rolling on the bearing surface afforded by the raceway bore 58. it will be seen that the center of gravity of each roller 61 describes a circular orbit. To maintain the roller 61 in proper engagement with the raceway 58 while the generator is at rest, or coming up to speed, the axle 62 of the rotor is provided with an axial pin 66 which rides around a circular boss 67 projecting inwardly from the sidewall 57 on the axis of the raceway bore 58.

The two rotors 6t are driven through a pair of driveshafts 74, each of which has a universal joint coupling '75 to the corresponding spur gear 64. The shafts '74 are connected through universal joints 76 to meshing spur gears 77 in gear box 23, the two spur gears 77 being coaxial with the raceway bores 58. Gears 77, and therefore the shafts 74 and spur gears 6 of rotors 68, are driven at the same speed in opposite directions through an idler gear 78 meshing with one of the gears '77, and a gear 711* meshing with idler gear 7% and mounted on the shaft of electric drive motor 27, as best seen in FIG. 3.

The operation of the vibration generator 12 is as follows: Rotation of shafts 74, in opposite directions, drives the two spur gears 64 around the internal gears 65, the two shafts 74-each moving in a conical gyratory fashion. The inertia rollers 61 roll on the bearing surfaces 53, so that the rotors 6t) move in orbital paths around the raceways 58. The centrifugal force developed by the rotors moving in these orbital paths is taken by the pressure of the rollers 61 on the surfaces of the constraining raceways 58 in the body or housing 55. The rollers 61 turn at nearly the same rate of rotation as the gears 64, with any slight variation or creep therebetween accommodated by the rotatable mounting of the rollers 61 on gear shafts 62. The two inertia rotors thus exert gyratory forces on the housing 55. The rotors 60, however, are so phased that the vertical components of their motions will always be in phase or in step with one another, while the horizontal components of their motions will always be equal and opposed. This is accomplished in the original setting of the rotors by means of the interconnecting gearing. For example, as shown in FIG. 4, the two rotors may be set so that they are at their extreme outermost positions simultaneously with one another. Accordingly, the rotors move horizontally with equal and opposed movements, and a little reflection will show that the horizontal components of the centrifugal forces exerted thereby on the housing 55 are equal and opposed and cancel within the housing. 011 the other hand, as may readily be seen, the gyrating rotors move vertically in step with one another, so the vertical components of the centrifugal forces exerted against the housing 55 are equal and in phase, and the forces experienced by the housing 55 are therefore additive in the vertical direction. The housing 55 therefore exerts on the T-head of the rod 13 an oscillating or alternating force along a vertical direction line.

It will be observed that the type of generator disclosed has a desirable frequency step-up characteristic from drive motor input to vibratory housing output force, in that for each orbital trip of a given gear 64 and its corresponding inertia roller 61 around the inside of internal gear 65 and raceway bore 58, the shaft 74, gear 64 and roller 61 make only a small fraction of a complete revolution on their own axes. The shafts 74 thus gyrate in their conical paths at greater frequency than their own rotational frequency on their own axes. Thus the orbital frequency of the inertia rotors 61, and the vibration output frequency of the generator housing, is correspondingly multiplied over the rotational frequency of the driveshafts 74. High vibration frequencies are thereby achieved without use of high-speed motors, or large gear ratios between the motor and the vibration generator. A simple, low-speed drive motor may thus be used, and a vibration of high output frequency obtained therefrom in a simple manner.

The sonic wave or vibration generator 12 is driven by motor 27 and through gear box 28 at a speed to generate its output alternating force at a frequency which is such as will generate a longitudinal elastic standing Wave in the rod 13. It will be observed that the generator 12 is mounted directly on the upper end of the rod 13 and hence applies its vertically oriented alternating force to the upper end of the rod 13. It will also be noted that the rod 13 is supported by the sleeve 31 in the region of the longitudinal center of the rod 13. The generator 12 will generate a half-wave length longitudinal standing wave in the rod 13 if its frequency is made substantially equal to S/2L, where S is the speed of sound in the material of the rod and L is its length. Such half-wave length standing wave operation is the fundamental mode of vibration, through harmonic frequencies may be employed if desired. Assuming, however, the half-wave mode of standing wave vibration, the rod 13, under the influence of the alternating force impulses exerted on its upper end, alternately elastically elongates and contracts. The center region, where the bar is mounted on the sleeve 31, stands virtually stationary, the wave at this point having a node N. The sleeve 31 therefore functions to isolate the power unit from vibration in rod 13. The upper and lower end point antinodes V. The housing of the vibration generator 12 will be seen to vibrate vertically at the amplitude encountered at the upper antinode V. Obviously, this vibration cannot be transmitted back through the shafts 74 to the gear box 28 and housing 10, though said shafts 7 4 may swing vertically to some added extent about the pivot centers of universal. joints 76 by reason of vertical vibrations'of the generator housing.

The core tube 15 coupled to the lower end portion of the rod 13 is also made equal to any multiple (including unity) of half-wave lengths in overall length, and the standing wave behavior of the rod 13 continues on down through the walls of the core tube, such that a velocity antinode V appears at the lower end of the core tube. The upper end of the core tube, of course, vibrates with the lower end of the rod 13. Nodes and antinodes appear along the length of the core tube, as indicated.

The lower end of the core tube may initially have located therein a frangible plug 80, in order to exclude the firstlayers of useless, muddy material. This plug breaks and falls away as soon as sonic wave action is started in the core tube. The upper end of the core tube is ported, as at 81, to permit escape of otherwise trapped water as the core is received in the core tube.

Operation is as follows: The apparatus as described is lowered from a ship or barge on flexible cable 11, using any suitable or conventional lowering equipment. The apparatus is lowered until the core tube 15 has made engagement with the ocean floor, and by allowing the weight of the apparatus to be imposed on the core tube stem, the latter will force its way down, by gravity, through the upper layers of soft, muddy material. It will of course 6 be understood that the length of made such as to assure penetration as deep into the formation at it may in any given instance be desired to sample the formation.- Thus, the core tube 15 may be made considerably longer than as indicated in FIG. 2, and the possibility of such extra length is shown by the break in the core tube in FIG. 1. In any event, however, the core tube length should preferably always be equal or close to an integral'nurnber of half-wavelengths, so as to assure a resonant longitudinal standing wave not only in the rod 13 but also in the core tube 15. Specifically, it is desired that there be a velocity antinode, and therefore maximized vibration, at the lower end of the core tube where the core is severed from the formation and caused to enter into the core tube.

Once the apparatus has been lowered sufiiciently and is in proper position for coring, the necessary switching operation of relay circuit 48 is carried on at the top to cause operation of relay 47 to energize electric drive motor 27 from the batteries 44. The sonic wave generator 12 is thereby set into operation, and establishes the resonant standing wave condition represented in FIG. 5 in the verti cal stem 17 consisting of the solid elastic rod 13 and the elastic core tube 15. Suspension cable 11 is lowered sufliciently to permit at least some of the weight of the power unit to be imposed through the rod 13 and core tube 15 onto the formation, at least during the half cycles of elastic elongation of the stem. Under these described circumstances of wave action in the core tube and downward or bias pressure of the core tube against the formation, the core tube rapidly severs and receives a core from the formation. The core is severed by a fluidization effect which the sonically vibratory lower end edge of the core tube has on the formation when acoustically coupled to the formation in the manner just described.

The sonic core taking machine of the invention inherently tends toward maintaining itself in an upright position. The machine alternates between two conditions. The first is during elastic elongation, while the core tube is penetrating. The other is during the next phase of the cycle while the core tube is contracting, and thereby mo mentarily hanging from the suspension system. During this latter phase, the momentarily suspended machine tends toward, uprightness owing to the action of gravity. The penetration phase of the core tube is of such short duration as not to afford much opportunity for tipping of the apparatus from its vertically upright position before th core tube begins an elastic retraction which again suspends it from its support, bringing on a corrective tendency back toward uprightness. Thus, there has been provided a sonic coring tool which will penetrate rapidly into the formation of the ocean floor, and in a controlled vertical direction, even though solely supported from a cable. The invention thus combines sonic penetration, simple cable suspension, and self-guidance for preservation of vertical orientation.

A further feature of importance is the practical feasibility of the use of self-contained batteries in the power unit, in lieu of a surface located source of electrical energy, with the attendant complication of an electric power cable for conveying the electric energy down to the electric motor in the power unit. A battery pack self-contained in the power unit would be considered to be impracticable if the wave generator were of a type which could be stalled in the event of stalling of the vibratory core tube. In such event, of course, the electric motor would also stall, and become a short circuit across the batteries such as would quickly ruin them. The present vibration generator 12, however, will permit the motor driven rotors to obit freely, notwithstanding stalling of the core tube and the vibratory generator housing. This follows because, in the apparatus of the invention, the coupling between the motor and the vibrator housing is acoustic in character. This means that the rotary parts of the wave generator continue to rotate freely, no matter what the environmental conditions the core tube 15 will be at the core tube. The invention thus possesses the very great advantage of a battery power source for the motor, and an acoustic type of load system which is incapable of stalling the motor.

Broadly, of course, the present invention may be practiced with use of a power source above, and a power cable leading downward to the batteries in the housing 10. Also, the suspension cable may, if desired, contain an electrical conductor for this purpose. The sonic standing wave system maintained in the core tube facilitates the sliding of the core up into the core tube. As mentioned earlier, the core is severed from the information by the acoustic wave action at the lower edge of the core tube, where the core tube is acoustically coupled to the formation. Sonic waves are effectively radiated from the lower edge of the core tube into the earth material in immediate contact therewith, and a sonic fluidization etfect is produced in the earth material in this annular region. A core is thereby cut, and such core is then, in effect, extruded up into the core tube. The sonic wave action in the core tube, adjacent the entering core, creates a fluidization type of effect on the surface of the core, and facilitates its travel up the tube. By virtue of this sonic action, long lengths of core, of substantial volume, can be taken during one round trip of the core tool. The battery type of power unit is very well suited to these conditions.

One further advantage of the system, as compared with conventional rotary coring, is the ability to use a simple cable support, since the sonically vibrated core tube does not require rotation.

The drawings and description will be understood to be merely illustrative of and not restrictive on the scope of the invention, since many changes in design, structure and arrangement may be made without departing from the spirit and scope of the invention, as defined in the appended claims.

I claim:

1. In a coring tool for obtaining a core from earthen formation from an underwater location, the combination of:

a vertically oriented elastic stem, at least the lower portion of which comprises a core tube,

a unitary power unit structure at the upper end of said stem,

a sonic frequency elastic wave generator in said power unit acoustically coupled to said stem and operable at a longitudinal resonant frequency of said stem so as to establish a longitudinal elastic standing wave vibration in said stem,

motor means in said power unit structure drivingly connected to said wave generator,

, and a cable suspension system with tension control supporting said power unit structure and said stem under water in a vertically hanging position, with the core tube portion of said stem acoustically coupled to said underwater earthen formation with an acoustic coupling bias whereby said formation has sonic energy transmitted therethrough as it flows as a core into said core tube.

2. The subject matter of claim 1, wherein said power unit structure comprises a housing for said wave generator and motor means, connected to an upper end portion of said stern, said motor means comprising a rotary electric motor, and a battery pack for said electric motor enclosed within said housing, and

said generator includes at least one rotor-mass movable relative to said stem with its center of gravity describing a circular path of travel about an axis transverse to said stem and at said resonant frequency of said stem and including also, fixed to said stern, a constraining means which constrains said rotor-mass to motion with its center of gravity describing said circular path of travel, said rotary electric motor being drivingly connected to said motor-mass for so moving the same, and said constraining means and said stem being subject, by virtue of said constraint, to an oscillating force developed by said movement of said rotor-mass, whereby said stem has said elastic standing Wave vibration established therein, and whereby, in event of stalling of said stem against said standing wave vibration, said electric motor and generator continue their operation without interference thereby.

References Cited by the Examiner UNITED STATES PATENTS 1,966,446 7/34 Hayes -56 XR 2,650,068 8/53 Rand 1756 2,665,885 1/54 Gignoux 175-6 2,704,333 3/55 Calosi et a1 51-59 2,778,230 1/57 Peterson 74-61 2,829,527 4/58 Fleming 74-61 2,880,969 4/59 Williams 175-245 2,903,242 9/59 Bodine 175-56 XR 2,975,846 3/61 Bodine 175-55 XR 3,023,820 3/62 Desvaux et al 175-55 3,098,533 7/63 Ostrom 175-6 FOREIGN PATENTS 80,532 4/20 Austria.

CHARLES E. OCONNELL, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,194,326 July 13, 1965 Albert G. Bodine, Jr.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7, line 46, after "unit" insert structure Signed and sealed this 18th day of January 1966.

RNEST W. SWIDER nesting Officer EDWARD J. BRENNER Commissioner of Patents

Claims (1)

1. IN CORING TOOL FOR OBTAINING A CORE FROM EARTHEN FORMATION FROM AN UNDERWATER LOCATION, THE COMBINATION OF: A VERTICALLY ORIENTED ELASTIC STEM, AT LEAST THE LOWER PORTION OF WHICH COMPRISES A CORE TUBE, A UNITARY POWER UNIT STRUCTURE AT THE UPPER END OF SAID STEM, A SONIC FREQUENCY ELASTIC WAVE GENERATOR IN SAID POWER UNIT ACOUSTICALLY COUPLED TO SAID STEM AND OPERABLE AT A LONGITUDINAL RESONANT FREQUENCY OF SAID STEM SO AS TO ESTABLISH A LONGIDUTINAL ELASTIC STANDING WAVE VIBRATION IN SAID STEM, MOTOR MEANS IN SAID POWER UNIT STRUCTURE DRIVINGLY CONNECTED TO SAID WAVE GENERATOR, AND A CABLE SUSPENSION SYSTEM WITH TENSION CONTROL SUPPORTING SAID POWER UNIT STRUCTURE AND SAID STEM UNDER WATER IN A VERTICALLY HANGING POSITION, WITH THE CORE TUBE PORTION OF SAID STEM ACOUSTICALLY COUPLED TO SAID UNDERWATER EARTHEN FORMATION WITH AN ACOUSTIC COUPLING BIAS WHEREBY SAID FORMATION HAS SONIC ENERGY TRANSMITTED THERETHROUGH AS IT FLOWS AS A CORE INTO SAID CORE TUBE.

Images