US2486049A - Hydraulic propulsion system for boats - Google Patents

Description

Oct. 25, 1949. E. c. c. MILLER HYDRAULIC PROPULSION SYSTEM FOR BOATS Filed Dec. 6, 1945 E. OH

0N oN.

Patented Oct. 25, 1949 UNITED STATES PATENT OFFICE HYDRAULIC PROPULSION t SYSTEM FOR 'BOATS Ernest C. C. Miller, Laurelton, N. Y.

Application December .6, 1945, Serial No. 633,117.6

7 Claims. 1

This inventionis'ahydraulic propulsion system for boats, especially for smaller, :power driven boats, suchas launches, motor boats, and the like.

Withthe usual screwjpropelled boat, the engine is .generally iin thesternfof the boat and drives `a propeller shaft, `sloping'diagonally and rearwardly through ithe bottom of the boat. Such engine must be carefully alignedrwith the propeller shaft, andthe propeller vshaft passes through a bearing :which must be tight enough to keep out the Water., `and ymust be .adequately lubricated. The mounting 4of the engine and the propeller shaft as ziust described, requires Ia. considerable degree ofskill'an'dzadds considerably to the cost ofmanufacture ofthe fboat.

One :of 'the :most important. features of the present invention is vto eliminate the yusual propeller shaft .passing :through the bottom of .the boat, thereby, of course, eliminating the expense of the shaft, .the expense rof installing it, and the -use of lubricated `bearings vand packings for accommo'dating suohshaft.

The engine o'f :a motor boat also is rigidly mounted ;in `.the hull, -as it must be to keep'its alignment with :the ypropeller .shaft. With such a .rigid mounting, vthe vibration of the engine, especially with high powered engines, iis considerab1e,'an'dfis communicated to the hull of the boat.

Another :important :feature of .the invention .is to` mount `the engine .on .aresilientrshook absorbing .and :vibration absorbing Tbase, so .that the vibration 'from 4'the engine is not communicated to the hull of the boat, with the result that the operation of the boatis :quiet andsrnootn'as compared with one-where the yengine isrgidly. mounted lin tthe usual Way.

'Withthe usual motor boat, :the engine isfgenerallyin .the center of the :boat and sometimes isfveryrmuchA in the Way. :Another important feature of this invention is that the engine :need notbe mountedfin the centernf .the `boatin alignment withithepropellerishaft,1but;maybe .mounted inzanypconvenient .placeand may even extend transversely of the xhull, rather .than longitudinally, if such arrangement is desired.

"The foregoing and other .advantages 4are achieved by lthis invention, wherein thepropeller is :not mechanically Aconnected to 'fthe engine 'but is :drivenby a hydraulic motor, lthe fluid 4pressure for actuating 'the motor coming 'from a fpump driven'bythe engine. The pressure pump is connected .to the hydraulic motor by metallic pipes or by nonm'etallichose, such pressurepipes or hose extending .from `the pump, 'located in the peller.

.-2 boat, to the yhydraulic motor located-outboard-of the vboat, Athese pipes extending over the .gunwale at the stern or vthrough the stern -aboveor Lbelow the water line, or even vthrough the .bottom vof theboat.

Another valuable .feature of the .invention, re sulting from -the use of the hydraulic drive, is-.a graded .control --of the ,propeller .speed :and ready reversibility of the propeller, both .achieved by manually operated valve means ycontrolling the amount of pressure uidsupplied tothe .hydraulic motor. Gradual movement of the valve gradually varies thepressure andamountnf the .pressurefluid, to gradually .vary thespeed of the ,pro-

The uid .flow to the hydraulic .motor may-readily be reversed by .the valve, thereby reversing .the lpropeller. The described `controls `of -the propeller may `be effected without changing the Fspeed vor ldirection Vof rotation of the .engine orpump, and .without .theluse-ofgears or clutches, which are used to achieve .similar results with .a mechanical drive.

.Another .important Yfeature .of the invention is thatthe boatmay .he steered by pivoting .the propeller soas ,to .be moved to portfor starboard about a verticalaxis, thereby eliminating the use 4of a rudder. .This .pivotal movementmay be .effected manually, or by -hydraulic means, as will be described.

Still another important 'feature of Athe invention 'is the uprovision of the `expansion reservoir for the pressure iiuid.' Oil is preferred .as lthe pressure vuid andthe .term oil Willhereinafter be used, but it should be understood that Aany desired pressure fluid may lbeused instead of oil. In hydraulic vsystems under pressure, especially where the driving imotor is .operating continuously, vthe oil vtends to "increase rapidly in pressure iand temperature, even in normal operation, and especially if the hydraulic Amotor 'should jam. Increase of pressure 'is `taken care of by f an overload by-'pass valve, vand 'increase of temperature is 'taken care no'f bythe expansion reservoir, =of=a capacity "to allow `the oil to cool, 'and' wherein `vit drops to atmospheric pressure.

'The oil'under pressure may also be connected to drive other mechanism on the boat, such asfone or more Winches, for raising the anchor, etc.

Further advantages 4of `constructionand operation will be'described lby referenceto the accompanying drawing wherein:

Fig. lis a diagrammatic v#plan #view fof 1a, iboat provided with the hydraulic propulsion systemof this invention.

fFig. '2 'is a side 'view of fa modification.

Fig. 3 is a plan view of the structure of Fig. 2.

Figs. 4 and 5 are plan and side views of another modification.

Fig. 6 is a vertical cross section through a unit of the control valve.

Fig. 7 is a side view of a preferred mounting for the motor.

Referring now to these drawings, 2 indicates the hull of a small boat, having the usual stern 4. An internal combustion engine or other prime mover 8 is mounted on a suitable resilient base of any desired type, such as springs, a thick block of rubber, or on rubber mountings, as is well understood in the art of mounting machinery. In a typical mounting, motor 8 is mounted on a plurality of angle irons I I8, having horizontal webs H2, through which mounting bolts H4, affixed at one end in boat bottom |28, are passed. Compression springs H6 are placed between boat bottom H2, and additional compression springs H8 are located between horizontal webs I I2 and washers |22 which are held in a desirable position by nuts I24. The motor drives an oil pump 8, connected to the pressure pipe I which leads oil under pressure to a multiple direction control and overload valve assembly I2, which normally sends the pressure oil to pipe I4, which passes through or over the stern 4, and delivers the pressure oil to a hydraulic motor I8 of the conventional reversible type, directly connected to drive the shaft I1 of propeller I8. Engine 6 and pump 8 are mounted inboard. Motor I6 could be mounted inboard or outboard, as desired. The propellers could be fixed, as shown in Fig. 1, and steering effected by separate control of the propellers, as will be described in connection with Figs. 2-5. However, a `conventional rudder could be used, if desired, or one or both propellers could be mounted'to move about vertical axes, as shown in Figs. 2-5, for steering purposes.

After the oil leaves the motor I6, it enters pipe 28 which leads it back to the valve I2, which in turn delivers it into pipe 22 and thence into expansion reservoir 24, which in turn is connected by pipe 26vto thesuction side of the pump, thus completing the'oil circuit. Reservoir 24 is open to atmospheric pressure and so permits expansion and coolingvof the oil.

, A similar set of pipes, I4' and 28', leads oil to and from the second motor I8 connected to the driving shaft I1 of propeller I8', the returning oil being passed by the multi-way valve I2 to pipe 22 and thence to the expansion reservoir 24.

One unit of valve I2, such as 28, delivers oil under pressure to either pipe I4 or 20, so that the propeller can be driven in either direction, inaccordance with the oil supply. In other words, where pipe I4 is under pressure, pipe '20 is the oil return pipe, and where is under pressure, I4 is the oil return pipe. Valve unit 28 is controlled by a piston 38, connected to rod 32, in turn controlled by a manually operated handle 34, swinging movement of which reciprocates piston 30 back and forth, to supply oil under pressure Vto either pipe I4 or 28, to drive the propeller I8 forward or backward, intermediate positioning of handle 34 serving to place piston 38 in various intermediate positions, corresponding to various Iintermediate `speeds forward or reverse. i

A second and similar unit of valve I2, such as 28', controlled by piston 30', rod 32' and handle |28 and horizontal webs 34', effects a similar control of motor I8' and propeller I8'.

Excess pressure from any cause, such as stoppage of the motor or propeller, is taken care of 4by a by-pass overload valve, which is preferably incorporated as part of the valve assembly 28, to be described in more detail later.

The control of motors I8 and I8 is independent, so that steering is readily effected by driving the motors at different speeds, or in different directions, for a sharp turn.

A third unit of valve I2, shown at 38, connected to pipes 38 and 48, and controlled by piston 42, rod 44 and handle 48, delivers oil in either direction to a hydraulic motor 48, directly connected to a winch or other power mechanism 50, so that it may readily be driven in either direction, for raising or lowering the anchor, for example.

Referring now to the modification shown in Fig. 2, where the motor and propeller are pivoted for steering, a hydraulic motor 52, connected to drive shaft 53 of propeller 54, is mounted at the stern on a vertical rod 56, pivoted yto turn on a vertical axis in upper and lower brackets 58 and 88, secured to the hull. Turning of this motor about its vertical axis will evidently steer the boat. Such turning could be done manually, or by oil pressure. Where oil pressure is used, rod 58 is provided with a laterally extending arm 82 secured thereto, the outer end of which is slotted at 83 and connected by the slotv to an actuating arm 84, which arm is moved back and forth by piston 88 working in a hydraulic cylinder 68, oil under pressure being supplied to either side of the piston by pipes 10, controlled by a simple reversing valve like 28, Fig. 1, for supplying oil under pressure to either side of the piston, for steering the boat as desired. l

Oil under pressure is supplied tol the motor 52 by' pipes I4 and 20, controlled by valves like 28 and 34, as in Fig. 1. Pipes I4 and 20 are connected to the motor by iiexible hose 12.

Referring now to the modification shown in Figs. 4 and 5, where the hydraulic motor is above the water line, upper and lower brackets 14 and 16 secured to the hull support a vertical housing 18, so that the housing can turn in said brackets about a vertical axis. The hydraulic motor 88 is carried by the upper end of the housing and drives a vertical drive shaft 82, at the lower end of which is a bevel gear 84 driving the bevel gear 85, connected to shaft 88 of propeller 81.

Housing 18 could be turned manually about its vertical axis for steering, or it could be hydraulically controlled by a pistonl operated arm 64, as already described in Fig. 3. Oil is supplied in either direction to motor by flexible hose 12 as described in Fig. 3, to drive it forwardly or in reverse.

The control valve assembly I2 is preferably composed of a number of similar units, like the unit 28 shown in detail in Fig. 6. This unit is provided with a main oil passage 88, vcommunicating by passages I8", I4' and 20', with pressure pipe I8, and pipes I4 and 20, respectively. The main oil passage 88 is connectible with passages 88 and 90 forming part of a U-shaped exhaust or return passage 9|, connected to the oil return pipe 22 for leading oil back to reservoir 24.

The valve body is also provided with a pressure relief passage 92, communicating with passage 83 and so with main passage 88, and opening at its other end into exhaust passage 9|.v A

`comes excessive. .suiiicient for the valve vassembly l2.

able threaded.shaft-:96,frelieves `excess .pressure in vthexsystem andservesito `Eby-pass pressure oil to passage 9| if for any reason Ithe oil pressure belOne 'overload relief valve is The flow of oil through thevalve is controlled by piston 30, already described which is provided With three enlarged lheads 89', -99 and 93', for opening and closing passages x89, 90 and -9:3, 4respectively. Passages 89a, equalize the vpressure :on-.both sides of heads 89 and .90'.and so ybalance `the piston 130.

.Pistonll is also provided-With aI centralzpassa'ge 95, in communication with lateral holes 96, 91 and 98, drille'dinfheads 99', '93 and 99', respectively.

The :valve operates fas follows:

With the yparts in neutral position asin Fig. 6, oil under pressure from I passes into hole 91, flows both ways in 95, out thru holes 96 and 9B into exhaust passage 9! and so no oil would be supplied to the corresponding hydraulic motor.

To go forward, piston 39 is moved to the left, oil under pressure passing from pipe I9, thru that part of passage 38 to the right of head 93', out I4 to pipe I4 to the motor. Head 93 shuts off oil ow to 29' and passage 89. Oil returning from the motor comes in thru pipe 29 and passes thru part of 88 and out passage 89 to exhaust passage 9|.

To reverse the motor to back the boat, piston 39 is moved to the right, oil under pressure passing from pipe I9, thru that part of passage 88 to the left of head 93', out 20 to pipe 20 to the motor. Head 93 shuts 01T oil flow to I4 and passage 90. Oil returning from the motor comes in thru pipe I4 and passes thru a part of 88 and part 99 to exhaust passage 9|.

Intermediate positioning of piston 39 between the forward and reverse positions gives corresponding intermediate propeller speeds forward and reverse.

There has thus been described a hydraulic drive for a boat, wherein one or more propellers can be driven in either direction at any desired speed without using mechanical clutches and gear shifts, and wherein steering can be erlected by driving two propellers at different speeds, or by using one propeller and pivoting it to move about a vertical axis. This steering can also be done simply by manipulating a reversing valve. The entire installation is smooth and quiet, because the motor is mounted on a resilient, shock absorbing base, and so engine vibration is not transmitted to the hull. |The usual propeller shaft, directly connected to the prime mover, is entirely eliminated, and the expense of its installation and upkeep is of course eliminated.

A particularly important advantage of the installation is that either the engine or propeller can very readily be disconnected for replacement or repair, simply by disconnecting the oil pipes and a few mounting bolts.

The provision of the expansion and cooling reservoir 2li is also important for allowing the oil to drop to atmospheric pressure and to cool off, thereby avoiding overheating of the oil, which is a serious problem, especially with more powerful engines.

While I have described the preferred ways of carrying out my invention, it should be understood that the invention is not to be limited to 6 the details illustrated, ibut .may fbe .icarried .out .in otherfways.

I claim as my invention: 1. :Propulsionimechanism :for ia boat, compris- .ing an engine, resilient, vibration absorbing .means .for .mountingsaid uengine, a .fluid pressure pump driven :by `saidengine, both =mounted inboard of the hull; a hydraulic motor, anda propellerr driven thereby, 4braiclretzn'leans "for mount- .ing' said'motor andzpropeller 'outboard of the'hull; pipes,operativelyzconnecting said pump and Vsaid *.hydraulicvmotor; an'dfvalve means `.for controlling the :suppl-y `of Vpressure fluid to 'said hydraulic motor.

S2. Propulsion ymechanism fora boat, compris- .inganiengina a fluid pressure pump driven .by said engine, Aboth mounted linboard `of the ;hull; .an :expansion reservoir ymounted inboard lof ythe hull; a hydraulic motor, and a wpropeller-:driven thereby, bracket means ior-mountingsaid motor .andpropeller outboard of 'the hull v pipes.-for leading fluid `under lpressure from lthe y pump :to the motor, thence to said reservoir, and thence to the suction side of the pump, and valve means for controlling the supply of pressure fluid in said pipes.

3. Propulsion mechanism for a boat, comprising an engine, resilient, vibration absorbing means for mounting said engine, a fluid pressure pump driven by said engine, both mounted inboard of the hull; an expansion reservoir mounted inboard of the hull; a hydraulic motor, and a propeller driven thereby, mounted outboard of the hull; pipes for leading fluid under pressure from the pump to the motor, thence to said reservoir, and thence to the suction side of the pump, and valve means for controlling the supply of pressure Iiuid in said pipes.

4. Propulsion mechanism for a boat, comprising an engine, a fluid pressure pump driven by said engine, both mounted inboard of the hull; a unitary assembly of a hydraulic motor and a propeller driven thereby, both mounted outboard of the hull; bracket means for said assembly of motor and propeller, mounted outboard of the hull, including means for pivotally mounting said assembly in said bracket means, to move about a vertical axis for steering purposes; pipes for operatively connecting said pump and said hydraulic motor, and valve means for controlling the flow of pressure fluid to the hydraulic motor.

5. Propulsion mechanism for a boat, comprising an engine, a fluid pressure pump driven by said engine, both mounted inboard of the hull; a unitary assembly of a hydraulic motor and a propeller driven thereby, both mounted `outboard of the hull; bracket means for said assembly of motor and propeller, mounted outboard of the hull, including means for pivotally mounting said assembly in said bracket means, to move about a Vertical axis for steering purposes, means, operated by pressure fluid from the pump, for effecting such pivotal steering movement of said assembly, pipes for operatively connecting said pump and said hydraulic motor, and valve means for controlling the fiow of pressure fluid to the said assembly of motor and propeller, mounted Y outboard of the hull, including means for pivotally mounting said assembly in said bracket means. to move about a Vertical axis for steering purposes, means, operated by pressure uid yfrom the pump, for effecting such pivotal steering movement of the assembly, pipes for operatively connecting said pump and said hydraulic motor, and valve means for controlling the ow of pressure fluid to the hydraulic motor.

7. Propulsion mechanism for a boat, comprising i an engine, and a uid pressure pump driven thereby, both mounted inboard of the hull; an expansion reservoir mounted inboard of the hull; a unitary assembly of a hydraulic motor and a propeller driven thereby; bracket means for said assembly of motor and propeller, for mounting said assembly outboard of the hull, including means for pvotally mounting said assembly in said bracket means to move about a vertical axis for steering purposes; means, operated by pressure fluid from the pump, for eiecting such pivotal steering movement of the assembly, pipes for leading pressure fluid from the pump to the hydraulic motor, thence to the expansion reservoir and thence to the suction side of the pump; and Valve means for controlling the flow of pressure uid as described.

ERNEST C. C. MILL REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 366,652 Harthan July 19, 1887 1,257,825 Eklund Feb. 26, 1918 1,908,144 Gross May 9, 1933 2,046,558 Hussman July 7, 1936 FOREIGN PATENTS Number Country Date 26,279 Great Britain NcV. 15, 1912 308,141 Great Britain Mar. 21, 1929

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