US2839021A

US2839021A - Automatic tension system for fueling at sea

Info

Publication number: US2839021A
Application number: US390227A
Authority: US
Inventors: Jr Joseph C Patterson
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-11-04
Filing date: 1953-11-04
Publication date: 1958-06-17
Anticipated expiration: 1975-06-17

Description

June 17, 1958 J. C. PATTERSQN, JR

AUTOMATIC TENSION SYSTEM FOR FUELING AT SEA Filed Nov. 4. 1953 6 Sheets-Sheet 1 INVENTOR ATTORNEYS June 17, 1958 J. c. PATTERSON, JR 2,839,021

AUTOMATIC TENSION. SYSTEM FOR FUELING AT SEA 6 Sheets-Sheet 2 Filed NOV. 4, 1953 I 1V VEN l' 0R Josq Paliemolm/Z ATTORNEYS June 17, 1958 J.c;'PA1rERsoN,JR 2,839,021

AUTOMATIC TENSION SYSTEM' FORFUELING AT SEA Filed Nov. 4, 195s f @sheets-sheet :s

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ATTORNEYS June 17, 1958 .1. c. PATTERSON, JR 2,839,021

AUTOMATIC TENSION SYSTEM FOR FUELING A'r SEA Filed Nov. 4, 1953 6 Sheets-Sheet 4 INVENTOR ATTORNEYS mM/@www June 17, 1958 .1. c. PATTERSON, JR 2,839,021

AUTOMATIC TENSION SYSTEM FOR `FUELING AT SEA I Filed Nov. 4, 1953 6 Sheets-Sheet 5 CGN TRO/ STAT/0N ATTORNEYS i June 17, 1958 J. c. PATTERSON, .1R 2,839,021

AUTOMATIC TENSION SYSTEM FOR FUELING AT SEA 6 Sheets-Sheet 6 Filed Nov. 4, 1953 AUTOMATIC TENSION SYSTEM FOR FUELING AT SEA Joseph C. Patterson, Jr., Falls Church, Va.

Application November 4, 1953, SerlalNo. 390,227

7 Claims. (Cl. 114-55) This' linvention relates to the transfer of material from ship to ship or from ship to shore as is involved in fueling atsea. In fueling at. sea a cable is run between the tanker and the ship being fueled and a hose is suspended from this line. Since both ships are subject to wave action, it is apparent that the tension on the supporting cable is subject to large and sudden variation. These changes in tension cannot be allowed either to overstretch or overslack the cable or to impose strain upon the hose supported thereby. Large'` and sudden variation in cable 'tension imposes very high horsepower demands upon. whatever equipment is used to remove tension and slack and, to provide the .needed horsepower on a tanker, has been a` major problem particularly with the advent of simultaneous fueling of several ships from the same` tanker.

lt isv .therefore an object of thisinvention to maintain proper tension on the hose supportingcable of a ship to ship refueling rig in a .fully automatic manner well within thel range of reasonable horsepower capacity of. tanker power plants.

According to the present invention it. is proposedj in simultaneous fueling, to use the energy produced in thatpart of the roll cycle when the tanker and one of the ships move apart to assist in meeting. the load of. slack removal caused by roll of the tanker 'and another of. the ships toward one another.

In particular it is an vobject of this invention to store or use the energy produced from: roll of a ship away' from the tanker in an accumulator arrangementI of large eapacity but of very high sensitivity so that responses are instantaneous and free from time lags caused by uncharged-lines,l vequipment inertia or friction.

Other objects and advantages of. this invention will be apparent from the following detailed description of several.v embodiments 'thereof .in conjunction with the 'annexed drawings wherein:

Figure l .is a schematic view .in elevation showing a central tanker simultaneously fueling a ship yon each side;

' Figure v2 is a hydraulic layout .showing the operating circuit for controlling the lines between the tanker and oneshi-p;

Figure -3 .is a view in vertical section of a vfour way valve for controlling a winch driving hydraulic B end, the valve Ibeing shownin neutral position;

i .Figure 4 is a view of the valve of Figure' 3 in haulingin and automatic tensioning position;

. Figure 5 is a view of the valve ofvFigure '3 in payingoutV position;

Figure 6 is a view in vertical section of a pressure relief valve of the type used vin the ksystem of Figure' 2; Figure 7 is a view .in vertical section of a iiow controlA valve 'of the type used in thesystem :of Figure .2;

,- Figure 8 is a view in vertical section of a 'pressure' reducing valve of the type used in the system of Figure 2;

Figure 9 is a hydraulic layout similar to that of Figure 2 butshowing an. arrangement for 'charging accumulators in a manner to vary the pressure delivered thereby;

2,839,021 Patented June 17, 1958 Figure 10 is a. view in. vertical section of a modied pressure compensator pilot valve of the type used in the system of Figures 9, 1l andk 12;

Figure l1 is another hydraulic layout similar to that of 'Figure 2 which shows' another scheme for varying the accumulator pressure;

Figure 12. is still another hydraulic layout similar to that. of Figure 2v but Vshowing a further modiii'ed scheme for varying accumulator pressure;

Figure 13 is a view partly'in side elevation and partly in. section of a control valve used with the arrangement of Figure 12; and.

Figure 14 is a. fragmentary top plan view of the control valve of Figure 13.

Referringnow tozFigure 1, a tankerequipped according to the 'present invention is designatedA by the reference character' T while the ships being fueled are designated S-l'and S-Z. During fueling, a cable 10 is rigged between the tanker T, the' movable supply, and the ship S-l and a rsimilar line. 11 is rigged between the tanker T andthe ship S2,4 ships S-1 and S-Z being the movable use media.

Saddles

12 and 13 supported outboard of the tanker T from the cables 1i) and 1,1, respectively, function to support fueling hoses 14 and 1S, respectively. Theriggings between the movable supply, tanker T, and the movable. use media, ship S-1 and ship S-2, are each horizontally supported from the deck of tanker T by Xed vertically 'extending king posts 10a and 11a. In place of king posts, however, booms, which can be pivotally supported `and guyed into place, can be used to support the riggin'gs. The position of the outboard saddles is controlled by cables 16 and '17, respectively. Inboard sad- -dles 18 and` 19 are supported and positioned by cables Zl andi 21,V respectively. Cables 10, 11, 116, 17, 20 and 21 are controlled by

separate Winches

23, 23a, 30, 30a, 3S and 35a which" are carried on vthe deck of tanker T, -the movable supply. These winches and their operation will be apparent from Figure2 in which ythe machinery for operating the cables 10, 16 and 20' is shown in detail.

'Beforefdescribing Figure 2 it will be well to note that the arrangement shown in regard to cables 10, 1-6V and 20 i's repeated on theother side of the ship for cables 11, 17 and 21. Furthermore, even thoughonly two fueling stations on ship T are shown, there may be various numbers ofV such stations depending upon the sizeof the ship. There is, however, advantage in having an even number of fueling' stations equally distributed on opposite sidesv of the ship as will hereinafter more fully appear. The equipment on the shipsv S-l and S-2 forms no part of the present invention since all controls` on the lines are maintained from the tanker T. In general the ships being fueled which is the m-ovable usek media will have some sort of cable attachment structures to receive Vthe cables- 10 and 11. One ytype is schematically indicated in Figure 1 over a sheave 2'2- 'to a winch 23 which is driven through

gears

24, 25, 26 and 27 from the B end 28 of a hydraulic transmission which is a hydraulic motor-pump unit. Cable 16 passes overa sheave '29 to a winch 30 which is connected to a planetary type diierentiall gear system 31. The planets of the diierential system `are connected to` the B end 32 of a 'hydraulic transmission while the sun. gear of the dilerential. system 31 is connected through a gear 33 lto the gear 24 on `the shaft of winch /23 in .y a manner to cause a 1:1 speed ratio between the drums s, j 20 and winch 35.*which are arranged with the winch 3'5v urging cable 20 in the direction of take-up, the saddle From Figure 2 it will be seen that the cable 10 'passes' 18 is'pulled against the bracket 110 of sheave '34 and maintained in this position until a force is exerted on saddle 18 by hose 14 suticient to overcome the pull by cable 20. When this predetermined tension in hose 14 occurs, the hose 14 will y,function to cause cable 20 to override and pay out thus moving saddle 18 away from sheave bracket 110' and relieving the excesstension in hose 14 until such time as an equilibrium will be established between the tension on hose 14 and the tendency of cable 20 to take-up. When the tension. on hose 14 falls below the predetermined tension, the Winch 35 will act to take-up cable 20 until saddle 18 rests against sheave bracket 110'. f

The hydraulic transmissions that include driven or B ends of the hydraulic motor-

pump units

28, 32 and 37 in# clude a single pumping or A end 38. is driven directly or througha 'gearebox 39- by a prime mover steam turbine 40. Pressure liquid is'also supplied to the B endsfrom accumulators 41 and'v 42. Before describing the supply ofp'ressure vliquid to the B ends and the controls imposed thereon, it is well to note .that the B ends 28, 32 and 37 which are capable. of acting as motor units for driving

Winches

23, 30 and 35, respectively, when high pressure liquid' from the accumulators is permitted to ow to thewinches, and as pumps to pump fluid under pressure into. the 'high` pressure side of the accumulators when torsional load is applied to the winches and the Aend 38 'are not 'shown in detail herein since they are hydraulic piston and cylinder units of the well known type, typical specimens of which are fully shown in Patent 2,554,381. y The A end 38 is of the adjustable tilt plate type shown in the said patent. i n

The description of the operation of the circuit of Figure 2 will be commenced under the assumed conditin that the lines 10 and 11 are already rigged and that the equipment is operating normally to keep them properly tensoned. After introducing the various structural parts in their performance of this function, the operation of the same parts during rigging and under emergency conditions will be discussed.

When the liquid tlow to and from the B end 28 is as indicated by the arrows in Figure 2, the B end is turning the winch 23 in a cable hauling in direction. When the ship and tanker roll apart, the B end 28 is overhauled and the direction ofthe liquid ow is opposite to that shown in Figure 2. When the ow is as shown in Figure 2, high pressure liquid is supplied through conduit 44 which is connected through conduit 45 to the high pressure main 46 leading into the high pressure chambers of accumulators 41 and 42, for example, chamber 43 of accumulator 41. High pressure main 46 This A end is also connectedV to a feed line 47 from the A end 38 I of the system. The high pressure liquid supplied to the conduit 44 passes through a flow control valve 87 of the type shown in Figure 7 and enters a 4-way reversing valve 49 shown in considerable detail in Figures 3, 4 and 5. With the valve 49 in the Figure 4 position, the pressure liquid from conduit 44 enters at chamber 50 and passes through a gate 51, the valve housing space 52 and a gate' 53 to chamber 54, which is connected by pipe 55 to the B end 28.

Working liquid returning from the B end 28 passes through a conduit 56 into the chamber 57 of the valve 49, again see Figure 4, and from the chamber 57 flows through gate 58 and valve body space 52 to manifolded chamber 59. Chamber 59 is connected by conduit 60 to low pressure conduit 61 which is, in turn, connected to the low pressure side of accumulators 41 and 42 by the line 62. Y

When the ships roll apart while the valve 49 is in the Figure 4 position, the winch 23 is driven Iby the cable 10 which reverses the B end 28 against the force of the pressure uid. This converts the B vend` 28 into a pump and causes it to pump liquid through the line 55,

through the-valve 49 into line 44,'through check valve 48 and through a valve 110 and line 45 to the high pressure side of the accumulators 41 and 42. This, of course, charges the accumulators and stores energy which can be used later in the roll cycle of the ships when the haulingin operation is again required to keep the cables 10 and 20 adequately taut.

If now reference is again made to Figure 1, it can be seen that when ships Tand S-1 are rolling away from one another so that B end 28 is charging the accumulators, the B end which operates cable 11 is required to haul-in. Some of the horse power requirements of this action on the cable 11 can helmet by the energy delivered through B end 28. The B end which operates cable 11 is operatively connected to the accumulators 41 and 42 arranged in parallel through conduit 46. `Since the structure is the same for both sides of the ship, the B end systemV servingcable 11 is not shown but the conduits whichconnect ltofit are shown in Figure 2 at A63' and 64. It can be seen that with simultaneous fueling the tanker is always rolling Vaway from a ship or ships on one side of it and toward a ship or ships on the other side of it.V Thus the B end or ends which vare beingroverhauled are pumping fluid into the system at the very moment when-.the Bends which'are hauling in, l

need the working iluid.v This greatly reduces the' Arnak'e up liquid required to keep the accumulators charged and hence reduces the-load onv the tankers power supply.) vUpon reference to Figures 3, 4 and 5, the details ofA valve 49as well as valves 70 and 71 can ber understood. It will be seen that the valve body space 52 of the valve 49 is generally cylindrical in shape and is subdivided Y axiallyl by pistons 65, 66 and 67 fixed in spaced relation along an operating shaft 68. As has been explained, when the shaft 68 is in the Figure 4 position, chambers 50 and 54 are interconnected and so are chambers 57 and 59. This-is the position for either hauling-in or automatic operation. On the other hand, during rigging, when the line 10 is initially payed out, valve 49 is set to the Figure 5 position. In this position pressure liquid enters chamber 50 and leaves through chamber 57, being delivered to B unit 28 through the conduit 56. Working liquid returning from the B end 28 through conduit 55 enters valve 49 at chamber 54 and leaves through chamber 59 to low pressure line 60.

During the time that accumulators 41 and 42 are initially charged, which is before the line 10 is payed out, the valves 49, 70 and 71 are set to a neutral position shown in Figure 3 in which flow to and from B ends 28, 32 and 37 is blocked by pistons 65, 66 and 67. Once the accumulators are charged, by the pumping action of the A end 38 delivering to the system from liquid storage reservoir 69 through line 47, the line 10 may be payed out. Thus, when the line 10 is connected to ship S-1, the system is made ready for automatic tensioning by gradually transferring valve 49 from the Figure 5 to the Figure 4 position.

Thus far nothing has been said regarding B ends 32 and 37. It should be noted, however, that the valve 70 is exactly like valve 49 except that it controls B end 37 and that valve 71, also exactly like valve 49, controls B end 32. The low pressure working liquid line 61 is directed into valve 71 by branch conduit 111 and into valve 70 by branch conduit 72. The high pressure liquid is directed into the valves by lines 111' and 72.

Once the line 10 is in position between the tanker and the ships to be fueled and the hose is in

saddle

12 and 18, valve 70 is adjusted to the haul in position to lift the `hose 14 to the Figure l position. Valve 70 remains in haul-in position and the saddle 18 is pulled up hard against sheave bracket 110'. The position of saddle 12 is adjusted on line 10 by manipulating valve 71. When outboard saddle is in the right position, the valve 71 is set to neutral, Figure 3, position, whereby to lock the planets of differential 31. This causes the automatic gesegnet compensations of `B end 28 to adjustWinches- 23 and' 30 'simultaneously and in 'synchronisnr `SinceB end 32 is used only in saddle positioning, 'it is much smaller than B end 28 and B end 23 can easily resist any torque input from B end 32. Accordingly, manual adjustments of the saddle 12 are possible while B end 28 isoperating, it' being apparent that movement of the diierential planets will add or subtract from the movement imparted to gear 33, the desired direction being achieved by suitable positioning7 of valve 71. Note that since gears 24 and 33 mesh, vthey will move in opposite directions -whereby the reversal in the diiiierential will serve to bring winch 3d back to the same direction as winch 23. Hence when valve 7l is locked in neutral and valve 49 locked to 'the automatic or Figure 4 position, saddle 12 will be payed out when line 10 is being pulled out and saddle y12 will be` retrieved when line .10 is `being hauled in.

Saddle 18 is separately controlled from B end 37 but the arrangement is such that the valve 70 is set in the Figure 4 position so that the saddle is hoisted up against sheave bracket 110. Saddle 13 is held there and will not move unless the movement of the ships away from one another demands more length of hose 14 in which case the torque of B ends 28 and 37 will be overcome and cables and 2t) will be pulled out and cable V16 will be payed out. Consequently, saddles 12 and 18 are allo-wed outboard movement by the respective cables. This cable and saddle movement lifts more hose outboard of the ship, to meet the roll apart condition to prevent imposing excessive tension strains on the hose. It can be seen 'that hose is pulled out against the torque of B end 37, and hose is retrieved, when the ships roll toward each other, until the saddle 4support cornes up hard against bracket 110.

The winches 23, 3i? and 35 have, of course, very different loads to carry and their horsepower demands are quite different. It is contemplated Vthat winch 23 demands 150 horsepower while

winches

30 and 35, respectively, require only 35 and 50 horsepower. This gives a peak horsepower demand vof 235- but, due to the accumulators, the maximum l peak demand from the ships power supply is 75 horsepower and the average demand is only 35 horsepower. This being the case, turbine 49 can be quite small compared to .the Itotal H. P. of the units. Net only do the accumulators-41 and 42 'carry a considerable part of the horsepower demand, almost two-thirds at peak, but they also .have enough yreserve capacity to permit lines and hose to be retrieved without damage in case of a power failure on f he tanker.

From the foregoing it is appreciated `that steam turbine 40 must have a peak capacity of 75 horsepower. The A end 3.8, which it drives, is of the variable delivery or stroke type, but it also drives a constant delivery replenishing and servo pump 73. The servo pump 73 is driven from the gear box 39 and it draws liquid from the reservoir as does the A end 38. The pump 73 is connected through conduit 74 to a relief valve 75' which has an escape conduit 76 leading to reservoir 77. Pressure line 74 connects through conduit 78 to one way check ".alves 114 and 11S which allow the replenishing oil to enter either the high pressure or low pressure side. This compensa-tes for leakage. The pump 73 keeps the low pressure side of ythe system and accumulators at about 100 p. s. i.- so that the suction sides of the B lends 28, 32 and 37 are always underpressure which forces hydraulic liquid to the B ends thus avoiding shocks due to cavitation.

. Another highly important feature is the use of several accumulators in parallel. These accumulators, arranged.,

in parallel, have, individually, small pistons, but the ltotal capacity of the parallel group is large. If a single accumulator is used with a system of the type described, a

minor demand Ifor pressure fluid may result in a time lagv 6 and 'surges 'in accumulatorrpistorrrespense, but, y'with' several accumulators in parallel, the high 'horsepower capacity of a large accumulator is achieved together -With high sensitivity of one piston giving larger 'movementsfor small liquid demands. The result is that both major and minor demands for working liquid are met with equal speed and without large piston friction drag and inertia shocks. The accumulators 41 and 42 will be'rec'ognized as the dual piston type with both pistons fixed to and guided by a common central shaft. The vaccumulator 41 has a high pressure chamber 43 and a low pressure'chamber 43a. These chambers are connected in parallel with like chambers of accumulator 42. Only two piston accumulators are shown in the illustrations but it is 'evident that there could be any number connected in parallel.

It has been explained that the A end 38 is of the vari able stroke type in which the displacement per revolution can be varied from zero to maximum by 'adjustment of the tilt plate. A pressure responsive device 79 connected to high pressure line 47 adjusts the tilt plate ofthe A end 38 to meet the demands of the system. An identical arrangement is shown applied to the A end marked 69, which is shown in Figure 3 of Patent 2,554,381 consti tuting a conventional and'well known arrangement which, per se, forms no part of the present invention. Suitable relief valves are provided throughout `the system according to good prior art practice. Only one of these is shown but a description of the structure and vfunction of it will afford an understanding of the ktype of lrelief valves used. Figure 6 shows relief valve 75 in detail and from that figure the internal connections between

lines

74, 76 and 78 can be seen.

If operation is normal, flow through the valve 7'5 is from right to left as shown in Figure 6, i. e. opposite tothe direction of the arrows. `If back -pressure in line 78 becomes excessive, the `pressure through

orifices

80 and 81 will be sufficient to unseat ball l82 against spring 83. Because of 'the `small diameter `of orifice l80, 'the pressure in annular chamber 84 will fallbelow the pressure of

lines

74 and 78 with the result that piston 85 will move upwardly and unseat its valve part 86 whereby lines 74 to 78 are relieved through line'76.

It will be noted that 'the system of-Figure 2 is "prol vided with 'maximum ow control valves 87 to :91, inelusive. Valve 87 is shown 'in detail in Figure v7 and a description of it will suice for'valves 88 to `91, inclusive, which are of identical construction. The housing of valve 87 is provided with opposite ports l92 and *93 for con-f nection across the .high pressure line 44 lleading to valve 49. VIn the line 44 between the connections to jports and r93 there is the check valve 48. The elect of the valve A48 is to make 'high pressure output'frorn the accumulators flow through valve 87 while high pressure liquid delivered from the B end 2S, Whenthe ships are .rolling apart, is made to ow vto accumulators or the high pressure line through valve 48. AFlow to the B end 28 'is therefore metered and controlled to a maximum While` high pressure v'llow from it is not. Therefore valvev 87 prevents B end 28 from overspeeding in case line 10 becomesdisconnected.

The liquid entering port 92 reaches port 93 `through a piston valve 94 and an eccentric l95. The leccentric 95 defines an adjustable eccentric groove 9'6' which 1is used to limit the rate of liquid discharge from the valve. The shaft 95 may be turned to different positions and locked in place.` The rate of flow is maintained independently of operating pressure variations by interconr'iectingV the chamber 96 below the valve 94 with 'the 'port 93 b'y a narrow channel 97 leading to piston chamber V'98 andi another narrow channel 99 leading from piston chamber 98 to 'port 93, It is now evident that the pressure. in chamber`96 willalways be the same as the static pressure which is produced by fthe `weight 'of the .piston `10`0 and' ,the compression ofthe spring 101., If the pressure in port 92 rises, -the piston 100 also will rise and close the valve .94 until the rate of ow into chamber 96 is equal to that being discharged through groove 96'.

l 'The

valves

88, 89, 90 and 91 are structurally and functionally the' same as valve 87. They are located, how-4 ever, inthe lines between Lthe B ends 32 and 37 and their respective 4way valves 71 and 70 rather than between the high pressure accumulators 41 and 42 and the 4-way valve 49 as isthe case of ow control valve 87. Furthermore, as can be seen by the position of check valves 92' to 95', inclusive, the flow control elected by valves 88 to 91, inclusive, is in regard to liquid delivered from'rather than to the B ends 32 and 37. This limits the maximum speed of the B ends for both haul-in and pay-out irrespective of which side is pressurized. As B ends 32 and '37 have overhauling loads, the '.ow control valvesv prevent overspeed in the pay-out direction as well as in the haul-in direction. Speed control in the haul-in direction is needed in case a cable becomes disconnected.

Pressure reducing valves 96', 97 and 98' are employed in the system of FigureZ and the details` of construction of these valves can be understood upon reference to Figure 8 which is described in conjunction with}valve 98 which is in the high pressure line 46 leading to 4-,way valve 71. It will be understood that pressure reducing valves 97 and 98 are made necessary by the fact that the load borne by B ends 32 and37 is much less than that borne by B end 28 whereas the power and pressure of the system as a whole are calculated with the high load B end 28 in mind.

Pressure reducing valve 96' is ordinarily by-passed with stop valve 110 open; however, for rigging the lines, a lower pressure than accumulator pressure may be needed to obtain iine control of B end- 28. In such a case, valve 110 is closed which forces the oil to pass through the reducing valve 96' so that a lower predetermined pressurel is applied to B end 28.

The high pressure uid from the line 46 enters the valve 98' (Figure 8) at port 99' which leads into charnber 100' containing a piston 101 for actuating a valve 102 which controls ow from the chamber 100' to a chamber 103. The liquid leaves chamber 103 and enters chamber 104 at reduced presesure. Chamber 104 is in communication with a ball valve 105 and the upper part of chamber 100'. From chamber 104 the liquid ows to the valve 71 through port 106. If the volume flowing through valve 102 starts to become greater than is necessary to maintain the reduced pressure at port 106, pressure on the ball valve 105 will increase, the ball valve 105 will be depressed against the thrust of spring 107 and some liquid will drain from relief port 108. If the volume owing through .valve 102 is greater than the combined discharge from ports 106 and 108, the pressure in chamber 103 Will rise causing piston 101 to be depressed partly closing valve 102. The connections from the relief ports 108 of the valves 96', 97' and 98 are not shown in Figure 2 but it is to be understood that they return to the reservoir 77 by any suitable connections known to the art.

The inboard saddle winch 35, after it has positioned the inboard saddle 18, maintains a tension to prevent the hose 14 from beingoverstressed. During tensioning, the saddle y18 is pulled up against sheave bracket 110. Hose is pulled out against the torque of B end 37 and hose is hauled-in when the ships roll toward one another until the saddle support comes up tight against the bracket 110'. Note that a check valve 109 by-passes the pressure control valve 97 so that when the B end 37 is pumping, liquid is returned to the high pressure line 46 through valve 109', by-passing valve 97.

In Figure 2, broken line connections 49a, 70a, and 71a to the valves 49, 70 and 71 respectively indicate that those valves may be operated from a remote station 109 '8 if desired and convenient toa particular ship. Various modifications of the form of the invention here described will be apparent to those skilled in the art and it is there fore intended that the scope of the invention be construed on the basis of the appended claims.

In Figure 2, the line 171 from the accumulator 41 leads to an ordinary bank of high pressure airflasks charged by any sort of compressor, not shown. It is possible, however, to vary the torque output of the

Winches

23,30 and 35 from a small amount to maximum by variation of the air pressure of the main accumulators. One way in which this may be accomplished is by use of a remotely controlled pressure regulated air compressor as shown in Figure 9. In Figure 9, parts which are the same as parts shown in Figure 2 bear the same reference numerals and broken away pipes lead to the same parts as are more fully illustrated in Figure 2. In Figure 9, the association between the adjustment of the A end and the adjustment of the air or gas pressure on the accumulator is shown.

The numeral 172 represents an air compressor, the output of which is connected by a conduit 173 to the conduit 171 leading to accumulators 41 and 42. Inter connected with the conduit 171 is a manifold 174 leading to high pressure storage flasks 175. Conduit 173 also leads to an air cylinder 176, the details of which are shown in Figure l0. A connection shown in broken lines at 177 leads to the control station 109 where an operating handle 118 is disposed for -the purpose of adjusting the automatic pressure setting of the compressor 172 by any known expedient, not shown.

The assembly shown in Figure l0 comprises a piston 119 biased by a spring 120 to the lowermost position. Piston 119 is connected by a rod 121l to a tilt plate 122 of the A end 38. The spring 120 thus biases the tilt plate to maximum stroke. Below the piston 119 there is a working space which is connected by a line 123 with a valve 124. When pressure exists in the line 123 greater than that necessary to overcome the thrust of spring 120, the tilt of the tilt plate 122 is reduced and the stroke of the A end 38 is correspondingly reduced. Thus, when the liquid pressure in the line 123 is relatively low the stroke of the A end 38 is relatively large and it is working at high capacity to make up the pressure deciency in the system. When the pressure in the system is high enough, that will be felt in the line 123 and the spring 120 will be compressed, whereby the A end will be stroked to neutral.

The valve 124 delivers pressure liquid to the line 123 so that the operation described in the foregoing paragraph can take place. To this end there is located within the valve 124 a plunger 125 having thereon an annular groove 126 leading to a central chamber 127 and an annular groove 128 axially spaced from the groove 126. When pressure fluid is needed in the high pressure lines of the system and A end 38 should be working, the high pressure liquid comes from the high pressure line 46 through a line 129 into a port 130 leading to groove 126 and chamber 127. This liquid acts to bias the plunger to the left of its Figure l0 position. It s biased to the right by a spring 131. As the pressure is built up by the operation of the `A end eventually the pressure in the chamber 127 will be able to overcome the thrust of the spring 131 and the plunger 125 will move to the left of its Figure l0 position. When it does so, the groove 126 will interconnect

lines

129 and 123 whereby the high pressure from line 46 will be felt underneath the piston 119 and the spring 120 will be compressed.

By the use of the air cylinder 176 the magnitude of the pressure necessary to shift the plunger 125 can be adjusted. Thus piston 132 is connected by a rod 133 to a piston 134 which acts on the spring 131. Air from the line 173 is admitted into working space 135 to the left of piston 132 whereby the piston can be moved to the right to increase the loading on spring 131 to increase the presasso-c21- 9 Sure necessaryin the chamber- 127 to move -the plunger 125 to the left-to permit restoration of the-piston rod'121 to the zero stroke position. The connections at 137,

v

138, 139 and 140 are drains to sump tank 77.

It will be appreciated that the pump 172 will be equipped with an automatic pressure regulator which will cut it olf when air pressure has reached the value to which the regulator is set. The setting of the regulator is accomplished from station 118.

If more tension on the cables is required the regulator is set by station 118 to a higher pressure. The air compressor pumps air into the air asks and accumulators. This increased pressure is automatically rellected in the high pressure oil so that piston 125 of valve 124 would be displaced to the left if the higher air pressure was not also piped to cylinder 176 via pipe 173 to act as an automatic pressure setting adjustment on valve 124 which controls the stroking of A end 38. Piston 132 with its spring 135 is proportioned to automatically adjust the pressure setting of valve 124 as the air pressure is increased or decreased. Accordingly if the regulator is set for less pressure than existing in the system an air drain off from the asks and accumulators would be necessary. This is accomplished by the regulator on the compressor 172. As the air pressure is lowered this lower pressure is reflected in the high pressure oil so that the oil and air pressure are reduced together. Consequently Valve 124 is automatically set for the lower pressure and does not shift from whatever position it is in at the time the air pressure is regulated. i The varrangement described in connection with Figures 9 and 10 brings about variations in the pressure dilerence between the high and low pressure liquid lines by increasing the air loading on the high pressure accumulators.A It is apparent, however, that the same result can be achieved by introducing and regulating an yair pressure on the air side of the low pressure piston of the accumulators. This can be done either through a separate accumulator piston as shown in Figure l1 or through the regular low pressure piston as in Figure 12. In any case, the air pressure must be delivered to the low pressure side of the accumulator through an adjustable reducing valve such as that shown in Figures 13 and 14. The reducing valve of Figures 13 and 14 is generally indicated by a reference character 141. In both of Figures 11 and 12 the air compressor 172 is present as Well as the storage flasks 175. The compressor 172 is connected by a conduit 142 to the accumulator 41. The gas storage asks are connected through a manifold 143 to the conduit 142 and the conduit 142 is tapped by a line 144 which leads to the reducing valve 141. The reduced pressure on the far side of the reducing valve 141 is delivered in the case of Figure ll through a conduit 145 to an auxiliary cylinder 146 containing therein a piston 147 mounted on a shaft 148 to move with the main pistons of the accumulator. The line 145 is tapped at 149 and the line 149 feeds to an A end control device 150 which is exactly like the one shown in Figure except that the line 149 taps in at the pipe marked 136 in Figure l0 rather than at the pipe marked 173. In this case, 173 becomes a drain connection.

In the case of Figure l1 or 12 the high side air pressure on the accumulators is not varied. It remains at a predetermined fixed value. The air compressor 172 is used only as a source of air to charge the high pressure side. The compressor is under automatic pressure regulator control to hold the predetermined pressure. Air pressure from the high side is piped via the pressure reducing valve 141 to opposite end of the piston accumulators. In this way the elective air pressure on the accumulators is regulated so that the tension on the cables can be varied from a predetermined minimum to the maximum. By increasing the air pressure being delivered and heid by regulator 141- to the apposite-.end of the acoumulators the effective pressure' andJ-resulting oil pressure which dictates the output torque of the B ends is lowered.

The air pressure line 152 or v149 of Figures l1 and 12 respectively is connected to line 136 of Figure :10. By this means the pilot valve shown in Figure 10 is biased so that it shifts over at a lower oil pressure as the air pressure on the low pressure .piston accumulator is increased.

In Figure l2 the low pressure fluid is delivered through a conduit 151 to the upper side of low pressure .piston in the accumulator 41. Line 151 is tapped by aline 152 corresponding in function and structure to line 149 of Figure l1. The reducing valve 141 of Figures 13 and 14 is co-mprised of two ball valves 153 and 15'4 which are maintained a fixed distance apart by an intervening rod 155. The ball valve 153 is urged yby a spring 1'56 to seat on a plunger 157. The ball valve 154 is engageable with a seat in a plunger 158 mounted on a diaphragm 159 which is biased to the left of the Figure 13 position by a spring 160. A cam 161 acts against one end of the plunger 157, and the right side of the diaphragm 159 is vented to atmosphere. For a given pressure reduction the cam is adjusted in such a way that plunger 157 is moved enough to unseat Yball 153 while ball 154 is seated. Under these conditions, air will enter through the supply conduit, go past the ball y153 and exit through the chamber 162. As pressure builds up on the delivery side, the effect will be to move the diaphragm 159 to the richt, ultimately unseating ball valve 154 and permitting the high pressure air 'to vent to atmosphere through the port 163. y

It is to be understood that the structure of valve 141 forms no part of the present invention, the valve shown being a Westinghouse Air Brake Company product as described in their Bulletin 10M-2 of March 1949. lln the lcase of Figures 1l and l2, the cam L161 is adjustable by any known means from a control station 164 located at a convenient part of the ship through control line 164a.

What is claimed is:

l. A ship having a winch on each side, a cable extending from each Winch to a mass remote from each side of said ship, each winch maintaining its cable in a taut condition, a hydraulic motor-pump unit connected in driving relation to each winch, a high pressure accumulator, a low pressure accumulator, conduits interconnecting said accumulators in parallel branches through each unit whereby when ship roll causes the unit on one side of the ship to pump and charge the high pressure accumulator the other unit which is working at the same time is discharging said high pressure accumulator and means to maintain the pressure in the high pressure accumulator at a predetermined value.

2. In equipment for supporting a load between relatively movable supply and use media, winches supported by said media, a supporting cable operatively connected to and controlled by one of said winches, said supporting cable extending between said supply and use media a load supporting mechanism depending from said supporting cable, a positioning cable connected to said loadsupporting mechanism and to another of said Winches, a hydraulic motor unit connected to each winch, high and low pressure accumulator means, means to charge said accumulator means to a predetermined value, means to control the pressure difference between the high and low pressure sides of said accumulator means whereby to enable the tension on said cables to be varied, and selective means for interconnecting said high and low pressure accumulator means in circuit with each of said motor units.

3. The combination comprising a hydraulic motorpump unit, a variable load connected to said pump unit, a high pressure accumulator, a low pressure accumulator, means connecting said motor-pump unit in series with said accumulators so that the high pressure accumulator supplies the liquid under pressure to drive the unit or receives pressure liquid from the unit depending upon whether it can overcome the load, means to maintain the pressure in said accumulators above a predetermined minimum and means to control the pressure difference between said accumulators.

4. The vcombination comprising a winch, a hydraulic motor-pump unit connected in driving relation to the winch, a high pressure accumulator, a low pressure accumulator, conduits interconnecting said accumulators through said unit whereby when the winch is under load the uid from the high pressure accumulator drives the unit and exhausts to the low pressure accumulator and when the winch is load driven the unit pumps liquid from-the low pressure accumulator to the high pressure accumulator, a reservoir of operating uid, means connected to said reservoir to maintain the pressure in the accumulators above a predetermined value, and means to control the pressure difference between said accumulators to enable the load carrying ability of said winch to be changed,

5. In equipment for supporting a load between relatively movable supply and use media, Winches connected to said media, a supporting cable controlled by one of said Winches, said ysupporting cable extending between said media, load supporting mechanism depending from said supporting cable, a positioning cable connected to said load-supporting mechanism and to another of -said Winches, a hydraulic motor unit connected to each winch, pressure accumulators interconnected in parallel, a hydraulic pump unit, selective means to connect said accumulators in circuit with each of said motor units, automatic means to cause operation of said pump unit to maintain said accumulators charged to a predetermined pressure, and means to control the effective pressure in said accumulators whereby to enable the tension on said cables to be varied.

6. A combination comprising a winch, a hydraulic motor-pump unit connected in driving relation to the winch, a variable load on said winch whereby when said load is relatively large said winch drives said unit and when said load is relatively small said unit drives said winch, a high-pressure accumulator for supplying and receiving liquid under pressure to and fromsaid unit, a low-pressure accumulator for collecting and supplying liquid from and to said unit, means interconnecting said accumulators through said unit whereby, when said unit drives said winch, the liquid from the high-pressure accumulator drives said unit and exhausts to the lowpressure accumulator and, when said winch drives said unit, the unit pumps liquid to the high-pressure accumulator, a reservoir of operating liquid, and means connected to said reservoir and said accumulators to maintain the pressure in both the high-pressure and low-pressure accumulators above a predetermined value.

7. The combination of claim 6 in which the high and low pressure accumulators are of the piston and cylinder type each accumulator comprising a `piston and cylinder, the piston and cylinder of the high-pressure accumulator having the same displacement as that of the low-pressure accumulator and means rigidly interconnecting the piston of the high-pressure accumulator to the piston of the low-pressure accumulator.

References Cited in the file of this patent UNITED STATES PATENTS Re. 20,551 Rouse Nov. 9, 1937 619,073 Deering Feb. 7, 1899 619,074 Deering Feb. 7, 1899 1,296,669 Kuharchek Mar. 11, 1919 1,685,927 Miller Oct. 2, 1928 .2,290,479 Mercier Tuly 21, 1942 2,479,316 Connelly Aug. 16, 1949 2,554,381 Patterson May 22, 1951 2,595,248 Greer et al. May 6, 1952