US2455090A - Hydraulic marine steering gear for operating the rudders of ships - Google Patents

Description

Nov. 30, 1948. w. T. PRlTCHARD 2,455,090

HYDRAULIC MARINE STEERING GEAR FOR OPERATING THE RUDDERS OF SHIPS Filed June 8, 1944 3 Sheets-Sheet l NlfENTOR. I {(WWJJJJZJZM 197' 7' ORNEY Filed June 8, 1944 Nov. 30, 1948. 1 w. 'r. PRITCHARD 2,455,090

HYDRAULIC MARINE STEERING GEAR FOR OPERATING THE RUDDERS 0F SHIPS 3 She e'ts-Sheet 2 INVENTOR.

A 7' TORNEYS 5 Sheets-Sheet 3 I A 7 TOfPNE Y5 W. T. PRITCHARD HYDRAULIC MARINE STEERING GEAR FOR Nov. 30, 1948.

I OPERATING THE RUDDERS 0F SHIPS Filed June 8, 1944 Patented Nov. 30, 1948 HYDRAULIG MARINE spun-nine ornnn non oenna'rmamnn ltUnnnns oFwsnl-rs Wilmot T.""Britcha rd, Seattle? waish assignor to "stetson Ross Machine flbihpanyfi Seattle, Washg a corporation or Washington 1" Application J unei 8, 1944, 'Serial N6l539,342 'U l aiimS. (Clfi'fifl 5 2) 1 invention relates to hydraulic marine "steering gear for operating the rudder of a ship.

More particularly my invention relates'to' "providing in ahydraulic marine. steering"mec'lia- 'nism,.for.varying the speed of response of aships rudder to the pilot wheel 'such varying being of a controlled, adjustable, and continuous character throughout apredetermin'ed range'of capaci- .ties of the pump as between 50%to-100 and suchvarying :being rendered possible without-releasing the force operating at a givenmoment to maintain the rudder either in a given position oninmotion. Also, my invention provides for varying of-the character above deso'ribedfthe capacity of not only-one pump but two pumps in combined operation when the rudder is in motion or without in any wise interfering. with'thesteermg.

In a ship having a hydraulic steering.gear (sometimes called an engine) for operating'the rudder, it will be understood the operation of the pilot wheel inthe pilot house actually .operetes to .pump oil in a cylinder assembly called -the forward .telemotor,.which may be located-close to the wheel orjust beneath the wheels 'Thistelemotor is hydraulically. connected to an after -teie motor. The. plungers of the after telemotor are connected to .gear mechanismcalled .difierential, whichinturniunctions as control means forthe swash plate in a -variable deliveryn type of pump thereby determining-the capacity of the variable delivery type. of ..pump. 1 From the foregoing, it willbe understood thatldue to hydraulic connection from the forward. to the.- after ftelemotor, any movement of the steering wheel will produce a proportional movementof. the pump control. and therefore. movement of ithe rudder. At the same t-ime connected means is setv i1rm0- tion to stop the rudder at-the-position determined by-the wheel and to restore the swash plate to neutral position.

Such hydraulic steering gearfor ioperating the rudderv has thetiller mounted upon-the rudder stock and has each end of. the tiller connected to the center of a ram-disposed to move in and out of cylinders, one cylinder for each end of the ram. Thus, as there are two rams'fthere would be four cylinders. To pump the oil i'nto'the four cylinders to actuate theiram, ordinarily there are two pumps, often referred to as'the two-pump units.

Due to the necessity at times of maneuvering the ship'while adheringclosely to ag'iven course and to the necessity of operating'under routine conditions, and due to the necessity of providing for wear of parts; lost motion," leakage ofhy- 'draulic fluid, and due to the necessity at'the'same time forproviding for emergency situations as naval. engagements, storms,failure for mechanical reasons, maneuveringfiin. tortuous""'narrow 2:2 'channels';ortrarisfer of' oilor any -transfe1fat"sea to'anoth'er ship"tvhe're-operation in unison isrequired, there"develops a wide-range'of requirements" "respects" varying" speeds of response of the rudder to the pilot Whee1." "EXpre'ssed-inother words, this"means"varying the amount'oi "power tb'beiaifrplied to'the'rudder or'varying the capacity of the hydraulic pumps; A primary 1 object 'oriny invention is to" provide fors'uchrange-of requirements ano-parucuiar1ytnat suchvar'ying snan' be of a controlled, adius-table,and" continuous char-- 'a'cter throughout a "predetermined range; asbetweeii'so %""-to100inclusivefof capacitiesof a wearable eapacity type' pum "'Thepbjecfibf' my invention is to priivide mechanism hi'chshall render-possible such varyingfof *th apa'city' of thiilimp' orpum 's IE'Ven Whfle'the l'iid dr is him!- ing.-'- "-Be w partiou'larlywioted that the-successful carrying" out" "of operations? 'at sea and in" the emergency situationsaboveset forth; niaydepend wholly orindarge part'upon the steering-mechanism be'ing capable of chaini'ginQ'thSpeed of rudoer movement at all times." "In snorti r propose "providing a"steerihgrnechariism 'lriaving a rudder connected to" a pim ality"of rams and' cylinders hydraulically operatedf'by a= pluralityb'f'variable outpuvpum'ps"ivl'iicwmeclianism ischaracterized by""kiihg""oapeible 0f (5156fatl'il finder a" selectable predetermined maximum output of"thepunips singly or jai in ei daeme-sme time'havi'ngs'uch "Output capaplepr change even "while the riidder ismoving.Thus"when{thefshipis bein'g'k'teer'ed ina zigzagcoursoimdodeini torpedoes-not asecond of time would beilfostin"'caus'ingres'ponseiof 'theship to" thddesiredhapacity ofthe pum s in applyingthedesired-power'to th trudder. I'p'urpose providingfor such varying'pf capacityof a continuous character not only of .one pump operating "butalso orthe'twupumps of a dual installationroperatingiiri combination.

"Since"the"'utijlity of a 'ship' depends' inlarge measurei-uponits maneuverability and this in turn depends upon ithe' properend efficient. operation or the rudder'withrespect'tothe speedo'f the "Ship, a"primary"objectof"my'irivention is a) to proivici fofadjustihg' thecapacity "of'the pump to minimum requirements, ""(b) to "provide "for? in'- creasing the "power applied: tothe rudder by in ereasingfthec'a'pacity of th'e pump in emergency when"h'igh' activity ofthe rudder is 'necessar and (trio-pr vi e seouri'tyobtainedby having a' 'wide range "of selectivity ofoi era'tion of'parts of a diial unit mechanism.

illustrating a situation-where' myinvention solves a particularly 'di'fficult probleni'of maneuvering requiringg' iri ari'e'i'rceptionally high degree, exactnessoFsteering,"let it"b" noted'in "thetra'nS- fer of oil at-sea to another' ship; known. as'ioilmg; the""oiling"ship"which int/111 be assumed is "eqlli p'fid' with rhyfinvrition an'dithe shipiciw maintain the distance.

3 ing the oil arerequired to run parallel while the oil is being pumped from the oiler to the other vessel with a plurality of heavy lines extending from one ship to the other. The ships are secured in spaced relation by heavy hausers but they must be close enough to permit the booms to swing the oil lines to the ship to be supplied with oi. The ships are then steering slightly apart to Under such circumstances, the moving of the rudder at an exceedingly fast rate when in a rough sea and the ships are moving, there is required a particularly active rudder for successful carrying out of the transfer. The ship being supplied with the oil may have a very slow steering mechanism and therefore the steering mechanism of the oiler must provide the safety for both vessels. It will be understood that the vessels are proceeding at a reatively slow rate and this also is a feature which increases the requirement for an active rudder on thepartof the oiler. Myinvention has been found successfully to solve this situation.

Also, a primary object of my invention is to provide in effect an adjustable cam which is subject to being moved bythe pilot wheel.

Another primary. object of my invention is to provide means for varying the discharge volume of a cam controlled pump to obtain greater or less speetl of response of the rudder to the pilot wheel and at the same time not interrupt the operation of the pump or the force applied to the rudder which may be operating to hold it in a given position to which it has been or is being moved.

The above mentioned general objects of my invention together with others inherent in the same, are attained by'the mechanism illustrated in the following drawings, the same being a preferred exemplary form of embodiment of my invention, throughout which drawings like reference numerals indicate like parts: I

Figure 1 is a somewhat diagrammatic view showing an hydraulic steering gear embodying my invention; I

Fig. 2 is a side elevation of the same;

Fig. 3 is a vertical sectional view with parts in elevation and parts broken away, taken through the pump stroke adjusting means, differential control, and pumpj' Fig. 4 is a view in longitudinal section with parts in plan through the pump stroke adjusting means taken substantially on broken line 44 of Fig. 3;

and

Fig. 5 is a diagrammatic view showing pipes, valves and differential control means.

The most important units of mechanism that g0 to make up this steeringgear are designated in a general way in the drawings by the following numerals: I0 is a hydraulic ram means connected with a ships rudder; H is a steering control means or forward telemotorsuch control means is usually manual'y operated as by a pilot wheel in the pilot house but may be operated automatically by a Sperry unit; l2is a hydraulically operated after telemotor; i3 is a constantly driven variable volume pump, two of which are used to provide alternate or combined operating means; It is a differential gear and cam unit forming part of the pump controlling means which means is connected to and is common to each pump; i5 is a pump volume adjusting unit herein referred to as a stroke adjusting device, one being provided for each pump.

Preferably a pump unit 13, a differential gear and cam unit l4 and a stroke adjustment unit l5 are assembled into one piece of mechanism as shown in Fig. 3, and two of these assemblies are used in each steering gear as shown in Figs. 1 and 5.

The hydraulic ram unit l0 comprises two reciprocable paralel plungers or ram members 16 and l! having their end portions disposed respectively in four hydraulic cylinders l8, I9, 20 and 2i. A tiller 22 extends crosswise of the ram members I3 and I! and is operatively pivotally connected therewith for angular movement thereby. An upright rudder post or stock 23 is keyed to the tiller 22 intermediate the length of said tiller. A rudder 9, shown fragmentarily in Figs. 1 and 5, is secured to the stock 23. When either of the two ram members H3 or H is longitudinally movetl the tiller 22 and the rudder 9 connected therewith will be anguarly moved to steer the ship. Power may be applied to either or both ram members l6 and I1 and when one ram member is moved in one direction the other ram member will necessarily be moved in the opposite direction. Fluid under pressure is supplied to the cylinders l8, I9, 20 and 2i through suitable pipes hereinafter described. To provide two-way rudder actuating means, the cylinders l8, I9, 20 and 2f are operated in pairs and opposed relation.

Anguar movement of the tiller 22 also transmits a follow up motion to two horizontal gear racks 24 in order to stop the movement of the rudder 9 at the position predetermined by the movement of a pilot wheel 30. Said gear racks are moved by means such as rods 25, upright levers 26, shafts 2i, upright levers 28, and links 29. The rods 25 are pivotally connected with the end portions of the tiller 22 and the links 29 are pivotally connected with the gear racks 24.

The gear racks 24 transmit follow up movement to the differential gear and cam unit l4 through which the pump is controlled as hereinafter described. In order to provide for simultaneous movement of the racks 24 in the same direction, gear segments 8 shown diagrammatically in Fig. 2, are provided in the means connecting one of said racks 24 with the tiller 22.

The steering control unit or forward telemotor H is of standard construction, is usually located in the pilot house of the ship and is provided with the usual manually operated pilot Wheel 30. This steering control unit H has a hydraulic connection through pipes 35 with the after telemotor l2.

The after telemotor l2 may comprise two hydralic cylinders 32 and 33 operatively receiving the end portions of a ram or plunger 34. The plunger 34 has an operating connection with two upright gear racks 35 by means, such as a forked member 36, lever arm 31, shaft 38, lever arms 39, and links All. The gear racks 35 transmit movement to the differential gear and cam unit 14 through which the pump is controlled as hereinafter described.

Each pump unit i3 is of a rotary, variable delivery or displacement type with axially disposed reciprocable pistons operated by swash plate means. In the drawings 4 l Fig. 3, is a pump housing and 42 is a front valve or manifold plate connected with inlet and discharge conduits means 43. 44 is a cylinder block having cylinders 45 for the reception of pistons 46. A suitable number of pistons 48 and cylinders 45 may be provided and said pistons and cylinders are arranged at spaced intervals around the axis of the pump and substantially parallel with said axis. 41 is a motor driven main shaft that is connected by key means 48 with the cylinder barrel or block and by universaltype-jointmean's i with swashplate means 50. 5 I--is-*'an angularly aiddustable receptacle or tilting-box within which-the swash plate means 59 is'- rotatively supitiorted by -bearing means -52. 53 are connecting rods that connect the pistons it' with the swash plate means 50. Each pump shaft 4'! is connected with an electric motor t i, "Fig: l and 2; by which* the pump -is driven cons-t'ahtly when in 'use.

When the tilting box "5 I; and swash'platemeans 56' are po'sitioned at 'right angles to the lshaft il, as shown 'in' Fig-.- 3; rotary motion f the swash plate'itill and the cylindrical bar-rel t willnot 1 produce any longitudinal'moilement of the-pistons 5 I3 and -no-- liquidivill be pumped. l -"Ii the tilting bo'x it and swash pl'atemeans 5t areinclined rela- 'tive to the axis offshaft i it then I rotary movement of these' parts and: the barrel- M will reciprocate the pistons 46. The amount of inclination im- -parted to the tilting box -54 and swash platemeans -5ll will determine the: stroke of: the .pistons 56. -Ihedireetion of inclination of these-parts Hand E 50: will determine which of the-conduits 63 is an 'inletandw-which is anoutlet conduit. Thus the d-irection of flowof the liquid that is being. circulated by a pump' unit lt :may be varied, neuiitrali-zed;:orwreversed' by. angular adjustment of the tilting box 5! :andswashplate means fit. The @above; mode of operation of the pump is that iwhich charactei'lzes thistype of variable delivery --.pump.

nLet-it betnoted'that' instead of theraxially disposed piston type of variable delivery pump above i described,..the radiallyledisposed piston type of t ivariable delivery pump maybe substituted or em- .wployed.

@The means for tilting the box 5i. comprises. a arearwardly.rextendingstub shaft 55 rigidly coni nected with said box Elto'one sideof the center othereof (it e.,- shaft-55 lies behind main shaft ll in Thearod' 5i extends upwardly out of the pump .ehousing through'bearing and packing means 58. The upper end" portionof saiclrod 5'17 is positioned 'within thesh'ousing 59 of thetpump stroke ad- :Jjustmentunit; i5; Figs. 3 and 4, anclis provided :witha forkedportion fiil that is connected by links ii I" with-one-end portion of a lever armfi2.

- The :lever arm 62 is'fulcrumed on adjustable :pivot-meanscomprising a blockdit movable in a ;=.slot:fi iin;said lever arm'62. The-blockt3 is ful- .-=cru:medwon:an adjustable pivot pin 65 that is car .riedby'two-spaced apart parallel pivot carrying bars 6t. .-*The-respective end portions of, the pivot acarrying bars-66 are secured to two head slides 61 and--58 that are supported for movement in tub- :nlarextensions 69 at the two'encls of the housing 59. A cover plate "Hlis secured to the tubular extension-69 that houses the headsl-ide ti and said ahead slide 6? is preferably provided with an adjustable stop bolt ll adapted to engage with the cover plate H! to limit adjustment in one direction cured as by cap screws 35 to the head slidej68.s

Theadjust-ing screw His-threaded through anut =.member-! 'i that is rotatively held in a hub 511' in l. the icover-plate 1'12. -An adjusting wheel 18 is 'sevoured torthe nut member :l6rbycapscrew-79.; A

i6 186M:is -iearried bysi thes;adiustingvwheelui t -and nto'az re'cess'itl in the cover plate adapted o-loole lz' topreventany but desired :movement of the wheel 'lB. An aid justable' stop .screw- 82 is pro- 5 vid'e'd' in the ad'j usting wheel 1 Biol iimiting moveme to'theright'f-Figl fii, on'thezadjusting. screw 73. "'l urningltheiadjlisting wheel lfi'w-illturn thenut mb'eri lfiiiandiiadjust the position of the pivot p t longitudinailyr as'.:respects. the lever t 2. *The end portionsofi'theilevenl'fih'shown atthe rightin-Eigs; S a'hdApis pivotally connected with 1 a forked rodifi'e iI heurodl83extends downwardly and-iis ifixedly' se'cured to a :plate or'crossheadM that is verticallyrzmovable: in the shousing- 85 of the differential 'g'earaand scam unit M. *Means such. as :guidei'members 86 'slid'ablysupport the edgeipo'rtions of thezplate'sor crosshead 84. The llplate M'carries'two roam: rollers B'l'thattare positioned'in engagenienti with aicam 88'fixedly setcuredhtor.punposesuof'toperation .on a sleeve 89. Rotary: movementi of the zcam 88 will .LsIidably move the plate or crossheadfflfliand this will move the: forked rod" 83oandi angularly move the. lever arm- 62 about *thes adjustable fulcrum pivot 55. 25 Angular movement of.:the lever 62 will vertically move'sthe pump'adjustingz'rod 5'! and change the angular position? of thertilting box =5 I andaswash plate '59 inithe pumpuunit l3 thus adjusting or c 'varyin g---the a-pistOn istroke: of. the pump. Mani- 3i) festly, shifting of.the ulcrum -pivot 65*varies the 'lengtha ofithe levertarms oneachiiside of said pivotwhereby: the amountofs'throw of pump adiujusting rod: El isiwaried.I-llObviously such shiftaingonzadjustingzofthafulcrum pivot 65 may be 1:5, done" while: the?mechanismsv is i in :operation and force is b'eingzaipplied to' the rudder 9.

A shaftitll} Figs; 3iand 5, is disposed within the isle'eVei'fSB; that "carries .the cam 88. Each shaft 9i! has aifixedlyrseouredigear wheel QL'Fig. uaithereon' that is .enga-ged by'one of theupright racks'iefi whereby each shaftfln'may be'rotatively moved-finresponse" 1102 movement? of the after telemotor l2 through' forked link 36 and-1connecta ingim-eans. :4 Each *shaft'ififliand 'the sleeve 89 thereon "arez'conn'ected lWith each sother by differ- "ential gear-means; comprising a 'bevel' gear 92 that is fixedly secured to the shaft Miami meshes with t other: bevel ge'ars 93 l whichvare carriediiby and 1 fixed wto' r-ithe l' sleevemifil .The bevel gears l 83' also mesh: with another bevel gear ied thatis rotatively mounted on the :sleeve 89.1 Thei'bevel-gear 94 is secured to ajsgear wheelififi that meshes-with 'another: gear wheel 96 ion a: counteresh'aft 9 l The "ir'count'ereshaft:3iIv has ar'geanwheel'cfifl that isenogagedi. byiionelz ofathex horizontal geart racks 2t --i v'hich zisazconnected iwithwthe hydraulic ram .o'unitfiii.

I' :cDue to :said idifierentiali mechanism and tiller connections thZGOHghZiIGdSL ZEfiUhGECW11 823 will al- 0- waysbesresitored to itszneutral position shown in Fig. 3 after movement oflilthez p'ilotwheel" 30 "has ibeenubrought to irestfat any desired: position. -1When .the'liafteriftelemotor 1- z' 'moves the upright :rackszz'iE in .:response;to force communicated. from the pilotwheelim eachishaft 90 willbe'rotatively imovedithe'rebygi This 1 will transmit rotary 'motion' in one iolirectionto' theicam58 8 through: sleeve W89 randtbeivelrgearsti'QZuandbQ3; t.This1imotion of the cam 88 will be communicateditwthe pump 'vox unitsils".thrOughcipartSS'B1e 84;:S'83',-i62; 5 Liand 5'5 ivandi 'willi'iangularlysL-mOveittheswash plates 50 v ithereofsintoizdesited zoil de'liveryr position. Either voneson rboth'iof lthe'ipumps -cwill abe'afieoted; :dea pending:onewhetherazone tor bothi #pumps are in isreadilyaretractableispringrpressed lockingtplungerii iazuse. iiilslsuallytin. inor'maliioperatiomiof thefuship only one pump will be in use. The delivery of oil or hydraulic fluid under pressure to the ram I operates said ram. Movement of said ram, communicated through tiller 22, rods 25, and associated connecting means, will move gear racks 24. Gear racks 24 will actuate gear wheels 98, counter-shaft 9'I, gear wheels 95 and 95, bevel gears 94 and 93, and sleeve 89 back to the cam 88. Thus movement of the ram means I0 automatically functions to return the cam 88 to its original neutral position. ;When the ram has traveled a predetermined distance proportional to the distance the pilot wheel 30 has been moved, the cam will be brought back to the neutral or inoperative position. Usually an indicator (not shown) is provided in connection with the pilot wheel 30 and the hereinabove described mechanism operates so that the .ships rudder 9 will always be angularly'moved the number of degrees indicated on this indicator in the direction indicated by said indicator, and thus the rudder position is determined.

Two pumping assemblies capable of separate and independent operation as well as combined operation are used in connection with each ram. Each of these assemblies comprises a pump I3, a difierential gear and cam unit I4 and a stroke adjustment unit I5. A control valve 99 of standard construction is connected with each pump unit I3 by the two conduits 43.

The control valve 99 that is connected with the uppermost pump unit I3 shown in Fig. 5 is connected by main supply pipes I00 and I'0I with the outer end portions of the respective ram cylinders I3 and I9. Similarly, the control valve 99 that is connected with the lowermost pump unit I3, shown in Fig. 5, is connected by main supply pipes I02 and I03 with the outer end portions of the respective ram cylinders and 2 I.

Valves I04, I05, I06 and I0! are provided in the respective pipes I00, IOI, I02 and I03 preferably near the locations where these pipes connect with their respective cylinders.

A cross pipe III provided with a valve I08 is connected between the pipes I00 and I03 and a similar cross pipe I09 with: valve H0 is provided between pipes IM and I021.

Four by-pass pipes II2,.Ii3, H4 and 5 are also connected with the outer end portions of the hydraulic cylinders [8, I9, 20 and M and are respectively provided with valves H6, H1, H8 and I I9 preferably positioned near the cylinders.

The by-pass pipes H2, H3, '4, and H5 are interconnected as shown in the lower portion of Fig. 5 and provided with valves I20, I2I, I22, and

I23 by which by-passing of liquid between different cylinders may be selectively controlled. Any suitable arrangement of liquid supply tanks and reservoirs may be connected with the bypass pipes H2, H3, H4 and "5 by pipes I24 having valves I25 therein.

The conduits I00, IOI, I02, I03, I09 and III, Fig. 5, are high'pressure conduits. All of the remaining conduits shown in Fig. 5 are low pressure conduits. the low pressure conduits are therein shown by dot and dash lines to distinguish them, in this figure, from the high pressure conduits which are shown by full lines.

In the operation of this ships steering gear, movement of the wheel of steering control unit M will produce movement of the ram member 34 of the after telemotor I2. This movement of ram member 34 will be transmitted through parts 36, 31, 38,.39, 40,35, 9|, 90, 93, and 89 to As Fig. 5 is a diagrammatic view the cam 88. Rotary movement of cam 88, Fig. 3, will act through rollers 81 to vertically move the crosshead 84. This will vertically move the forked member 83 and angularly move lever arm 62. The angular movement of lever arm 62 will vertically move pump adjusting rod 51 and thus adjust the position of the swash plate 50. The pump I3 is driven continuously while in use and the position of the swash plate 50 determines the stroke of the pump pistons 56 as hereinbefore fully explained. The cam 88 is designed to provide for relatively rapid movement of the crosshead 84 between the position shown in Fig. 3, in which the pump unit I3 is neutral and the piston stroke is zero, and a position of full or maximum pump stroke in which one cam roller 81 will ride the larger diameter of the cam 88. Cam 88 and stroke adjusting means I5 move swash plate 50 or tilting box 5|.

The mode of operation of my invention is set forth in part in giving the technical description above. The following will supplement the above.

Recognized specification covering steering gears provide that such must be designed to move the rudder from hard over to hard over through 70 within 30 seconds when the ship is traveling at full speed ahead at the maximum designed ship horse power without the hydraulic pressure of the steering mechanism exceeding the rated pounds per square inch when a single pump is operating at not over 90 of full stroke and without exceeding the rated horse power of the pump motor specified.

The mode of operation of my invention is characterized by providing an infinite number of pump volume or capacity adjustments as between 60% and inclusive, thus rendering the varying of the pump capacity continuous in character within said range. The magnitude of the throw of the cam 88 is designed to move the swash plate 50 of the pump from neutral position or zero capacity of delivery to the desired specified maximum, 90%, capacity of the pump to which it is connected when the performance of said pump is as above specified. By providing the shiftable fulcrum pump stroke adjusting mechanism I5, Fig. 3, my invention provides for the swash plate 50 or tilting box 5| to be caused to move and respond to the movement of the cam 88 through an infinite number of adjustments, that is, through a continuously varying capacity of each pump with its cam acting singly in the range of 60% to 100% inclusive or the combined capacities of said pumps and their cams when said pumps are operated in combination. For example, when it is desired to have the power of both pumps available to insure desired rudder activity, both pumps may be put under load by employing the desired combined capacities of said pumps ranging from their combined minimum output to their combined maximum output. My invention provides this continuous varying adjustment of capacity of each pump or the combined pumps while at the same time without releasing the force which at the moment may be operating to maintain the rudder in a given position or in motion. This adjustment is accomplished in my invention by shifting the fulcrum 65 through the screw I3 and associated mechanism connected to hand wheel I8.

This adjustment provides the infinite number of adjustments because it may continuously vary the fulcrum 65 of the pivotally mounted pump adjusting means by reason of its slidably mounted fulcrum B5-said fulcrum 65 being thus mounted to trollablecontinuously increasing ;and.- .decreasing I means i as-respects pump capacity.

In the. eventthat the magnitude of the throw ofithe camlfit designedto-move the. swash plate fill'of-the fromuneu-tral .-or ,zero: capacity of dGHVBI'zSf'ftO ICSS or more; than..-the 490% stroke capacity, then-obviously my -invention may-{be employed to increase or decrease L respectively: the effective throw of the cam 88 by suitablesl i-fting toadjust-ithe capacity aboverthat atwhich -ithas been=.;working; As. an: :eXample;.--while a the pump initially-maybe designed-to-give a required degree. ofeservice at90%' of its capacity, when parts bew comei-wornor-smallxleakages developit maybe i neoessary-toladjust the pumpzabove said 90%; e

Itwill "be understood that the-cylinders-.-l 8, :J 9, Eflfiand 2 H with: theirconneetingpipes, both :high

pressureandr bypassing: pipes, are filledwith: hy-

pressure to cylindersl 9*3Ild720 as'one-pain -cylinders 1.8 sanduz l as ranother pains-the: oil under pressure; therein will-exertpressure on-both rams lfitand H. use and twovcylinders; as 20 and ZLware bypassed 10 to exhaust oredischarge fluid, at the, same time... Thus opposed'cylinders wouldbe cylinders I 8 and. IE, or '29 amaze or 88 and 20,01. lQT'andZ'IL.

The rams...l6 and l! always move in-opposite directions due to their interconnection by thetiller 22 and irrespective of whether force is.-. applied to one or both of said rams. Also, whenever these rams are'moving, two cylinders will. always be exhausting or by-passingifiuid either back to a pump or from one cylinder to another.

When'any twocylinders are idling,i. e.,' are notcommunicatively. ,connected' with a pump. that isin operation, then it becomes necessary .to in.-- terconnect said .cylinders through the by-pass conduits H2,- ll3, 1M andrl l5. One way to use both pumps to supply-fluid under pressure to both rams isto open valves I04; Idfiflflfi and I01: 1 and close all. other valves. When this is done. the-two pump units will be independent1y1con-- nected one with the two cylinders l8 and {Sandthe other with the twozcylinders Hand ZL- If valves I08 and-l It. are opened alongwith valves I04, I05, I06 and, I8} then the. circulation sys-- terns formed by conduits we, NH, Hi2 and 1% will .be 'communicatively. connected with each other and the two pump units; can be: used jointly to. supply fluid'under pressure in both rams. If the use of one of the adjustablepumpunitsis discon-.:- tinued while valves ,lM,- lilfi;r;'lilti, illl; H33 and.-

30111"! are openand all by-pass valves are closed by the oi1,th'en% the:oiluunder pressure irt cylinder? 1 Bord 9 willzbe exertedoniram -ifib. Similar opera-- tion;.-'o'ccurs as-to ram l lrwhen oylinders20:0r 2L... are" subjected t c-"oil: under pressure and cylinders i ii and 1-9 arez-bypassed y Eachpumphasra capa city to #operate? [both qrams' l 6* and 1H. By protainedon the .rudder g to"hold it-in':whatever post tioni it may be theneoccupying. through-the stroke v adjusting unit 5 5 interposed between camrfltrand the swash plate 5Eljrit is obviousthata great'range of: selectivityoi the number of cylindersas 'Well as H the eapacityhunder which said. cylinders are to ,be operated is provided byi'my 'i'nvention: without in any wise interferin'gnwith thernormaleopera-tion' of the pilot wheel or otheniparts of-rthe' steeringmechanism.

The stroke adiusting unit l5 operates between? the cam 83 and 'the1tilting;boi 5! or swash plate 50 to vary the eifective stroke of the cam, i. e., to vary the amount of angular movement that a predetermined constant throw of the cam 88 will impartto the' swash plateau- As such adjustment is made by moving the pivot or fulcrum of lever 62 toward and away fromthepivotmember that connects the forked arm 63 with the lever 52 the pump adjusting rod 51 and tilting box 5l -fand swash plate fiflwi'll'always bereturned to thesameneutral position"irrespective of how much" they ders. When fluidund'erpressureis being supplied to one ramcylinderthen' fluid." is always exhaust- The term" inc." from; an opposed ram" cylinder. opposed cylinders refers to any two ram cylinders in which ram members are moving in opposed relation, i. e., one to admit fluid and the other then the other'adjustable pump unit alone; can be used to supply'fluid under-pressureto both rams. Thus, when a pumpunia-with itsassociated piping isg operating;.-it. will always-take. care of the exhaustfluid' from the cylinders opeposed to thoseto which it is "supplying fiuidnunsw der pressure.

Also, both adjustable pump units or either'adjustable pump unitmay be use to supply fluid 1.40! under pressure to only one cylinder at a titre.-- vidin'grior' a continuing..varying'reapaci-ty of-=the pumps and'ithis while the"; force: is 'fbell'lfgomainr-i member l6.- Similarl if high pressure valves.

I06, l01,-l08 and Ill] and low pressure valves 1 it, H7 and I20 arev opened and all other valves closed then both adjustablepump units may bemused-jointly, to apply. power. through ram member .l Tvvh ile ram member lfiidles or either.

of. saidadjustable pump units maybe so-used if the .otherpump unit is not operatingn I It-is also possibleto use the two .opposed .cyl. inders IB- and Zl as operating cylindersin con-. nection' with bothioreither :of the adjustable. pump units by opening high pressure valves 1 i! 5,; IOII;-l fl8;and .l l0 and low pressure valves l lB,-,I l8 and. 123 and closing all. other valves. In a similarqmanner it is .-possib1eto use the two opposed cylinders :18 and 28 as operating cylinders in conneotionwith both or either of the adjustable pump: units-by opening highpres-v sure valves 104 106; 38 and Hi] and lowapresev sure valves 1 IT, 1 I B and l 2i and'closing: all other." valves.-

Obviously .5 when the uppermost I adjustable. pumpiunit. lshowni-n' Fig. 5 -is beingused to: apply: power only to the ram member i 6 then the valves I08 and I I0 may be closed. Similarly these valves I08 and H0 may be closed when power is being applied to the ram member I1 only by the lowermost adjustable pump unit shown in Fig. 5.

From the foregoing description it will be seen that the two adjustable pump units can be used jointl in connection with all of theram cylinders or in connection with any two opposed ram cylinders or either of said pump units can be used singly in connection with all of the ram cylinders or in connection with any two opposed ram cylinders. Thus, in the event parts of the steering gear are damaged or become inoperative it will always be possible to operate the steering gear successfully as long as one pump unit and two opposed cylinders and the connections therebetween remain in condition for operation.

The use of the various above combinations of cylinders is possible with my invention without even momentarily interrupting the steering operation or normal operation of the rudder due to the fact that change in pump capacities may be made without interrupting the force being applied to the rudder and thereby no loss of control of the maneuvering of the ship at any time results.

In the use of the two pump units independently, i. e., with both pumps operating and the two valves I08 and 109 closed, the pump'adjusting unit l provide a means for quickly and accurately adjusting either or both of said pumps while the steering gear is in operation so that each pump will do its share of the work and neither pump will be a drag on' the other.

Obviously, changes may be made in the forms, dimensions, and arrangement of the parts of my invention, without departing from the principle thereof, the above setting forth only a preferred form of embodiment.

I claim:

'1. In a hydraulically operated marine steering gear mechanism for selectively varying the rate of angular movement of a ships rudder in rev sponse toa ships pilot wheel, the combination of a motion transfer cam-like-means movable in response to a ships pilot wheel; and adjustable control means for varying the effective throw of said cam-llke-means comprising a lever, a slidably mounted fulcrum for said lever, and means for controllably sliding said fulcrum relative to the end portions of said lever, whereby the length of the lever arms of said lever may be varied; and adjustable power means for moving a ships rudder controlled by said cam-like-means.

2. A hydraulically operated marine steerin gear mechanism for selectively varying the rate of angular movement of a ships rudder in response to a ships pilot wheel comprising, a motion transfer cam-like-means movable in response to a ships pilot wheel; rollers to engage said camlike-means; slidable cross head mounting means for said rollers; hydraulic operating means connectable to a ships rudder; a variable output pump for hydraulically operating said hydraulic operating means; a lever having one end portion connected to said cross head and the other end portion connected to said pump; a slidably mounted fulcrum for said lever; and controllable means for sliding said fulcrum toward and away from the respective ends of said lever to adjust the effective throw of said cam-like-means.

3. A hydraulically operated marine steering gear mechanism for selectively varying the rate of angular movement of a ship's rudder in response to a ships pilot wheel comprising, a motion transfer cam-like-means movable in response to a ships pilot wheel; hydraulically operated ram means connectable to a ships rudder; a variable output pump for hydraulically operating said hydraulic ram means; a, lever having one end portion operatively connected to said camlike-means and the other end portion to said pump; a slidably mounted fulcrum for said lever; and controllable means for sliding said fulcrum toward and away from the respective ends of said lever to adjust the effective throw of said cam-like-means.

4. A hydraulically operated marine steering gear mechanism for selectively varying the rate of angular movement of a ships rudder in response to a ships pilot wheel comprising a motion transfer cam-like-means movable in response to a ships pilot wheel; hydraulically operated ram means connectable to a ships rudder; a variable output pump delivering liquid under pressure to said ram means; a cam-like-means operable by a ships pilot wheel; follow-up means connecting said ram means with said cam-likemeans; a lever having one end portion operatively connected with said cam-like-means and the other end portion with said pump; a slidably mounted fulcrum for said lever; and controllable means for sliding said fulcrum toward and away from the respective ends of said lever to adjust the effective throw of said cam-like-means.

5. A hydraulically operated marine steering gear mechanism for selectively varying the rate of angular movement of a ships rudder in response to a ships pilot wheel comprising, a motion transfer eam-like-means movable in response to a ships pilot wheel; two ram members connectable with a ship's rudder; cylinders in which the ram members respectively operate; two variable output pumps; conduit and valve means operatively connecting said pumps to said cylinders; two cam-like-means operable by a ships pilot wheel; two differential means each connected with one of said cam-like-means and connectable with a ships rudder; two levers, each having one end portion operatively connected with one of said cam-like-means and the other end portion with one of said pumps; a slidably mounted fulcrum for each of said levers; and controllable means for sliding each of said fulcrums toward and away from the respective ends of said lever to adjust the eifective throw of said camlikemeans.

WIIMOT T. PRITCHARD.

REFERENCES CITED The following references are of record in the file of this patent:

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