US3720400A

US3720400A - Cable drum gear apparatus

Info

Publication number: US3720400A
Application number: US00092739A
Authority: US
Inventors: H Potts
Original assignee: Garrett Corp
Current assignee: Garrett Corp
Priority date: 1970-11-25
Filing date: 1970-11-25
Publication date: 1973-03-13
Anticipated expiration: 1990-03-13
Also published as: CA942222A

Abstract

A self-propelled load-carrying vehicle traverses between supply and receiving vessels at sea, on a closed loop highline of two cable whips terminating at one of the vessels on a pair of drums mechanically interconnected by a differential gear assembly whose spider is coupled to a third drum having a cable coupled to a ram tensioner. In one vehicle docking mode rotation of one of the drums may be restrained by a brake mechanism, leaving the other drum to take in or pay out its cable whip in accordance with relative motion between the two vessels. In a second docking mode both drums take in or pay out both cable whips equally in accordance with relative motion between the two vessels.

Description

States 1 1 Potts 1March 13, 1973 CABLE DRUM GEAR APPARATUS 898,562 10 1953 Germany....... ........254 1s4 550,691 3/1923 France ..254/184 [75 1 Invent Ham'd Omam 228,612 2/1925 Great Britain ..254 1a4 Canada [73] Assignee: The Garrett Corp., Los Angeles, Primary Examiner-Ev0n C. Blunk Calif. Assistant Examiner.-Merle F. Maffei [22] Filed: 7 Nov. 25, 1970 AttorneyOrville R. Seidner and John N. Hazelwood [21] App1.No.: 92,739 [57] ABSTRACT i i A self-propelled load-carrying vehicle traverses [52] U.S. Cl. ..254/l72, 214/14, 254/184 b t n u l and receiving vessels at sea, on a [51] Int. Cl. .3661] 1/48 losed loop highline of two cable whips terminating at Field 0f Search 184, one of the vessels on a pair of drums mechanically in- 214/14 terconnected by a differential gear assembly whose spider is coupled to a third drum having a cable cou- [56] RefUences C'ted pled to a ram tensioner. In one vehicle docking mode UNlTED STATES PATENTS rotation of one of the drums may be restrainedby-a brake mechamsm, leaving the otherdrum to take 1n or 769,904 9/1904 Hunt ..254/184 a out its cable whip in accordance with relative m0- r tion between the two vessels. In a second docking a s ea 3,361,080 1/1968 Born et a1 ..254 172 mode q drums take "1 pay 9 wh'ps a equally in accordance w1th relative motion between FOREIGN PATENTS OR APPLICATIONS the two vessels- 151,362 8/1903 Germany ..254/184 9 Claims, 2 Drawing Figures l CABLE DRUM GEARAPPARATUS BACKGROUND OF THE INVENTION Replenishment of supplies for a vessel at sea is the basic problem confronted by this invention. As is known, transfers of materials and objects between ships at sea present a number of difficulties due in large part to the random motion produced by the roll or other erratic movements of the ships, these movements resulting in an almost constant variation in the spacing between the ships.

There have been proposed in the prior art many solutions to this problem, amongst which, for example, are those employing constant-tensioned highlines rigged temporarily between the ships and arranged to support a'load-carrying vehicle or trolley adapted to traverse the highline span between the ships. Common known highline arrangements are those in which a doublewhip cable line is reeved around a sheave or snatch block on the receiving ship with the cable whip ends attached to a pair of winch drums on the supply ship, and with constant tensioning means provided in connection with one or the other of the cable whips or winch drums tomaintain a predetermined constant tension on the whips of the highline during. use. A known ram-tensioner apparatus is commonly employed for the constant tensioning function. One winch drum is then employed for outhaul of the load-carrying vehicle and the other winch drum for inhaul. The obvious disadvantage of such an apparatus is the necessity for providing power to each of the winch drums. Such an arrangement necessarily includes power means for each winch drum or a complex system for transferring power from a single source to one or the other of the winch drums.

To eliminate the inhaul and outhaul winch apparatus it has subsequently been proposed to motorize the between-ships vehicle and thus achieve a self-propelled replenishment-at-sea system. The vehicle of this system includes three co-linear pulleys, the central one of which is the driver with a 120 wrap angle for the cable provided by idler pulleys on either side of it. This has been an important advance in the art in that it virtually eliminates sending and receiving heads and the inhaul/outhaul winches commonly used in conventional transfer systems.

This proposed system employs three cable drums, usually coaxially disposed on the supply vessel with two of the drums being attached to one shaft and the third drum on a shaft arranged for coupling to the other shaft by means of a clutch or else to be fixed against rotation by a brake means. The third drum and one of the pair have laid on them the end wraps of a closed loop. cable which constitutes the highline reeved around a sheave or snatch block on the receiving vessel. The second drum of the pair has a cable wrap reeved through a tensioning mechanism,.such as a ram tensioner, with .the other 'end of the tensioning cable terminating in a winch which merely serves to anchor the cable during load transfers effected, by the self-propelled trolley vehicle, with the tensioner paying out or taking in slack during relative ship movements.

The clutch device in such apparatus engages the two shafts to act as one when the trolley is docked at the receiving ship inasmuch as both whips of the highline and the drums to which they are attached move as a unit with the relative ship movements. However, the

clutch disengages the two shafts and the brake is set so that independent movement of one of the highline drums may take place when the trolley is clocked at the supply ship. This is necessary since the trolley is generally drivingly coupled to the lower whip, for example, in order to utilize its self-propelled feature.

The main disadvantage of this system is that whereas in one docking mode (for example, with the trolley docked at the receiving vessel) the ram tensioner cable between the tensioner and it corresponding drum displaces one foot for each foot of displacement of one ship relative to the other, in the other docking mode with the trolley docked at the supply vessel the ram tensioner cable moves two feet for each foot of ship relative displacement. Another disadvantage is that the system requires a complicated combination of clutch and brake mechanisms whose actions must be suitably coordinated when changing from one operational mode to the other.

SUMMARY OF THE INVENTION The present invention overcomes the disadvantages of the prior art by utilizing the advantageous threedrum approach in a new and novel assembly configura tion. The two drums having the highline-cable wraps are coupled to each other and to the ram tensioner cable drum by a mechanical power transmission arrangement. A preferred embodiment couples the three drums with a differential gear means, in which the ram tensioner drum is drivingly coupled to the spider gear which is meshed with gears drivingly coupled to the highline drums. One of the highline cable drums is arranged with a selectable restraint embodied in a simple brake band arrangement to provide the docking feature which in the apparatus of the prior art required both clutch and brake mechanisms.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration in fragmentary perspective of the invention in use; and

FIG. 2 is an elevation view, partially in cross-section and generally schematic in form, taken on the line 2-2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 transfer of supplies between vessels at sea while under way, such as the supply vessel schematically indicated fragmentarily at 10 and the receiving vessel similarly indicated at 12, is effected via a highline 14 rigged between the conventional portal frame 16 disposed on the yessel l0 and a strong-point 18 on the vessel 12. The load transfer is effected by a self-propelled vehicle or trolley 20 traversing the highline 14 which comprises a cable 22 reeved around I stowed on the supply ship until such time as a between-ships transfer is to be accomplished, at which time a messenger line is passed to the receiving ship to haul over the cable 22 for reeving around the pulley of the snatch block 24.

The vehicle is of known variety as mentioned hereinabove. As a part of its self-propelling apparatus it is provided with an internal power source coupled to its drive pulley, preferably an electric motor (not shown) which is provided with electric power through an electrical cable 38 reeved around an idler pulley 40 shown as mounted on the frame 16 but which may be disposed on a bracket secured on the block 30 and movable vertically therewith, if desired. The winch 42 serves to store the cable 38, with the operation of the apparatus so coordinated that the winch pays out or takes in the cable 38 with corresponding movement of the vehicle 20 on the highline 14.

A tensioning cable 44 is coupled through a ram tensioner device 46 with one cable end disposed on the cable winch apparatus 48 and the other end received and secured on the drum apparatus 36 in known manner, as will be more fully described in detail hereinbelow. The arrangement is such that the ram tensioner 46 pays out cable to the drum apparatus 36 when the latter apparatus pays out cable 22 upon separating movement of the vessels 10 and 12, and vice versa upon converging vessel movement, thereby maintaining a constant tension on the

whips

26 and 28 of the highline 14.

As thus far described, the transfer cable rigging and auxiliary apparatus, together with the vehicle apparatus on the highline, is well known and need not be described further in tedious detail since the inventive novelty is considered to reside in the arrangement of the drum apparatus 36 and its combination with the various elements shown in FIG. 1. The drum apparatus is depicted in more detail in the schematic illustration on FIG. 2 to which reference is now made.

The drum apparatus 36 has a mounting base 50 which supports a shaft 52 for rotation in the pillow blocks 54 and 56. Secured to the shaft 52, as by a key 58, is the drum 60 upon which is secured and wrapped one end of the tensioning cable 44. The ends of the outgoing and

return whips

26 and 28 of the cable 22 are wrapped and secured on the cable drums 62 and 64, respectively, which are mounted to be freely rotatable on the shaft 52. lt will be apparent to those skilled in the art that any one of several known means may be employed for securing the ends of the tensioning cable 44 and

cable whips

26 and 28 to the respective drums. The drums 62 and 64 are mechanically coupled to each other by a motion transmission means 66 shown as a differential gear arrangement comprising the spider gear 68 meshing with side gears 70 and 72 secured respectively tothe drums 62 and 64. The spider gear 68 is rotatably mounted on the differential spider 74 which is secured to the shaft 52 in conventional differential gear fashion. The spider 74 may have one or more additional spider gears such as the gear 76 to equalize the rotational load on the gears of the differential.

It should be noted that the lay of the cable 44 on the drum 60 is of the opposite hand to that of the lay of whip ends of the cable 22 on the drums 62 and 64. With this arrangement the ram tensioner 46 is enabled to maintain constant tension in the cable 22. It will also be noted that separating movement of the vessels results in both drums 62 and 64 paying out cable 22 and drum taking on cable 44 from the ram tensioner 46. Thus, the

load-carrying vehicle 20 can be docked and maintained stationary at the receiving vessel 12 since there will be no movement of the highline around the snatch block sheave 24. Likewise, if the vessels move toward each other, the drums 62 and 64 take on more of cable 22 with drum 60 paying out cable 44 to the ram tensioner However, different provisions must be made when the vehicle 20 is to dock at the supply vessel 10 since the lower return whip 28 must then be stationary with respect to the vessel 10. To this end the drum apparatus 36 is provided with a restraint means which is operable to restrain the drum 64 against rotation. The restraint means is preferably a simple brake band element 78 partially encircling a groove at one end of the drum 64. The band 78 is restrained against rotational movement by a brake band bracket or fixture 80 on the base 50 to which the band 78 is secured. A handwheel 82 is arranged to draw the ends of the band 78 toward each other and thereby clamp the drum 64 against rotation in known fashion.

When the drum 64 is thus clamped, the outgoing lower cable whip 28 is steady and fixed against movement relative to the frame 16, hence unmoving relative to the supply vessel 10. In this case the load-carrying trolley 20 may be held steady and unmoving relative to the vessel 10 for the purpose of taking on a load of supplies. It is apparent, of course, that this arrangement results in double running of the upper highline 26 around the block 24 with relative movement between the two vessels. Thus the line 26 would run out or in two feet for each one foot relative movement apart or together of the vessels 10 and 12. However, the differential gear arrangement as aforesaid has the net effect of one foot of movement of the cable 44 onto or off of the drum 60 with each two feet of running out or in of the upper whipline 26 on the drum 62. Hence one of the main disadvantages of the prior art systems is overcome by this invention.

Furthermore, it is seen that the relatively simple handling of the brake band arrangement by means of the handwheel 82 eliminates the complicated concurrent manipulation or coordination of the brake and clutch mechanisms required by the prior art.

I claim:

1. Cable drum apparatus comprising a. drum base means,

b. first and second cable drums mounted for rotation on said drum base means;

. strongpoint base means disposed for random variation spacing from said drum base means;

. a cable pulley mounted for rotation on said strongpoint base means;

. a loop of cable reeved around said pulley and having first and second cable whip portions terminating in ends thereof wrapped respectively on said first and second cable drums,

said whip portions being arranged for reeling onto and off from said drums with rotation thereof;

f. motion transmission means coupling said first and second drums for producing differential rotation thereof in response to movement of said strongpoint base means relative to said drum base means;

g. a third drum drivingly coupled to said motion transmission means;

h. .cable tension force means including a tensioner cable element connected to said third drum means and arranged to act on at least one of said first and second drums through said transmission means to impart a substantially constant tension to said loop of cable, and

i. means for selectively holding one of said whip portions stationary while allowing the other of said whip portions to rotate with its respective drum.

2. Theapparatus of claim 1 wherein said torque applying means includes a ram tensioner arrangement.

3. The apparatus of claim 1 wherein said drum base means is mounted on a floating supply vessel, and said strongpoint base means being mounted on a floating receiver vessel spaced from said supply vessel.

4. The apparatus of claim 1 wherein said means for selectively holding one of said whip portions comprises restraint means operable to selectively restrain one of said drums against rotation.

5. The apparatus of claim 1 in which said motion transmission means comprises a differential gear arrangement.

6. The apparatus of claim 1 in which said first and second drums are loosely disposed on a common shaft defining an axis of rotation for said first and second drums and said motion transmission means comprises a differential gear arrangement with one of the gears thereof affixed for revolution with said shaft about the axis thereof, said one gear being drivingly coupled to first and second gears fixed respectively to said first and second drums.

7. The apparatus of claim 6 wherein said means for selectively holding one of said whip portions comprises restraint means operable to selectively restrain one of said drums against rotation.

8. The apparatus of claim 2 in which said first and second drums are disposed freely rotatable on a common shaft.

9'. The apparatus of claim 8 in which said third drum is secured on said common shaft.

"UNITED STATES PATENT OFFICE CERTIFICATE OF RECTION Patent No. 3,720,400 Dat d March 13, 1973 Inventor(s) Harold L. Potts It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Claim 2, "torque applying" should be --ca'b1e tension force-.

Signed and sealed this" 13th day of November 1973.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. RENE D. TEGTMEYER Attesting Officer 7 Acting Commissioner of Patents R (10-69) USCOMM-DC seam-peg v & u.s. GOVERNMENT QBINTINGVQFFI'CVE: @969; 0-366-334'

Claims

1. Cable drum apparatus comprising a. drum base means, b. first and second cable drums mounted for rotation on said drum base means; c. strongpoint base means disposed for random variation spacing from said drum base means; d. a cable pulley mounted for rotation on said strongpoint base means; e. a loop of cable reeved around said pulley and having first and second cable whip portions terminating in ends thereof wrapped respectively on said first and second cable drums, said whip portions being arranged for reeling onto and off from said drums with rotation thereof; f. motion transmission means coupling said first and second drums for producing differential rotation thereof in response to movement of said strongpoint base means relative to said drum base means; g. a third drum drivingly coupled to said motion transmission means; h. cable tension force means including a tensioner cable element connected to said third drum means and arranged to act on at least one of said first and second drums through said transmission means to impart a substantially constant tension to said loop of cable, and i. means for selectively holding one of said whip portions stationary while allowing the other of said whip portions to rotate with its respective drum.

2. The apparatus of claim 1 wherein said torque applying means includes a ram tensioner arrangement.