US3034584A - Marine propulsion installations - Google Patents

Description

T. HINDMARCH MARINE PROPULSION INSTALLATIONS May 15, 1962 2 Sheets-Sheet 1 Filed Sept. 2. 1960 Z n /U&I27Z0l"' Clad/march) 1.

May 15, 1962 T. HINDMARCH MARINE PROPULSION INSTALLATIONS 2 Sheets-Sheet 2 Filed Sept. 2. 1960 I IIHH! United States Patent "ice 3,034,584 MARINE PROPULSION INSTALLATIONS Thomas Hindmarch, Lindo Lodge, Stanley Ave., Chesham, Buckinghamshire, England Filed Sept. 2, 1960, Ser. No. 53,743 Claims priority, application Great Britain Sept. 9, 1959 3 Claims. (Cl. 170-16032) This invention relates to marine propulsion installations which may include variable pitch propellers.

Certain known types of variable pitch propellers contain within the propeller shaft a pull-push rod which is actuated by an hydraulic ram. In operation oil under pressure is applied to one side or the other of the ram as required in order to impart a fore or aft movement to the rod. In the event of a failure of the oil supply the pitch of the propeller blades cannot be varied or locked, but instead, on rotation the blades are forced to feather as a result of the resistance of the water and take up a position of no load. The ship cannot then be propelled. Since the actuating mechanism is contained within the propeller shaft which is designed for rotation, there is great difiiculty in obtaining access, particularly while the ship is at sea. The general object of the present invention is to provide an arrangement by which in such an emergency the blades can be moved into a full ahead position and locked there to enable the ship to proceed to port under her own power. Another problem arises with ships which have reversing gears which depend for their operation on oil operated clutches. Circumstances of overheating from defective coolers, or other mishaps, might cause the hydraulic operated mechanisms to bind in an on or off position. With part of the installation according to the invention coupled to the oil distribution piping system, by detaching the most convenient union, and attaching a connection, and then applying a powerful force with the machinery stationary the stuck part may possibly be fieed without the necessity for dismantling.

The invention accordingly consists in a marine propulsion installation Within a variable pitch propeller which incorporates an auxiliary external high pressure oil or grease pump coupled through a passage extending through an outer casing to a piston or ram built into the propeller shaft the arrangement permitting high pressure to be applied to the piston or ram without dismantling the main machinery of the installation.

The invention further consists in a marine propulsion installation including means for the auxiliary actuation of the variable pitch propeller mechanism, in which a pull and push rod is actuated by hydraulic pressure transmitted through a main hydraulic piston, located within a cylinder which is integral with the rotatable propeller shaft and fed with pressure oil from a pressure pump and control valve, characterised in that there is a separate high pressure ram, which when in operation presses against the centre of the hydraulic main piston and which is 'located within a cylinder machined in the main propeller shaft or extension thereof, communicating with the outside of the shaft by means of drilled passages in the shaft, terminating in a non-return valve and which non-return valve is connected by means of a coupling when the propeller shaft is stationary to a source of pressure oil or grease pumped by manual or assisted operation at a pressure high enough to move the ram to force the main hydraulic piston to assume and to retain a fixed position corresponding to the ahead position of the blades.

The invention further consists in the installation as first described above but in which the main machinery piston and some of the main installation oil pressure channels are utilised in order to connect the emergency high pressure pump through to the piston or ram of the main 3,034,584 Patented May 15, 1962 machinery by actual liquid contact by disconnecting the main pressure piping or channels at a point nearest to the afiected part and of having a non-return valve and connection to complete the combination, using a hydraulic fluid of higher than normal viscosity but which is miscible with the normal oil so that service may be resumed without dismantling.

Among the advantages of this invention are:

(l) A complex hydraulic system need not be dismantled at sea.

(2) Minor stickages which would be eliminated eventually are avoided.

(3) In an emergency, the high expense of repairs, delays en route, and towage can be prevented.

(4) Its adaptability, in that the normal ships engine room staff can carry out repairs which hitherto required the services of a dockyard.

The problem, therefore is a serious one and the solution involves a practical and useful contribution to the art.

In one preferred form of the invention, an independent hydraulic ram is situated in a cylinder comprising a cen tral axial bore in the propeller shaft forward of the main operating piston and cylinder.

The lengths of the independent ram and cylinder are chosen so that in normal operation when the independent ram is fully retracted, it does not protrude into the main cylinder.

The independent cylinder is fed via an axial and a radial hole drilled in the shaft from a non-return valve and pipe coupling situated at the outside diameter of the shaft. To operate the emergency locking system, the shaft is stopped and a high pressure hand operated hydraulic pump is connected to the pipe coupling. Operating the hand pump moves the independent ram into contact with the main piston, which is then forced in the direction required to turn the blades into ahead pitch. The length of travel of the auxiliary ram may be arranged so that the correct pitch is obtained automatically.

The non-return valve prevents leakage and so holds the blades in the required pitch when the hand pump is disconnected. The seal used on the auxiliary ram is preferably one in which the pressure assists in providing the sealing action, e.g. a cup seal, in order to eliminate leakage, but should any leakage occur, and the blades in consequence move toward neutral pitch, the shaft can be stopped and the pressure restored.

The blades are at rest when operated and consequently unloaded, and a very high pressure may he used for the auxiliary ram, which may be therefore quite small in diameter yet move the blades to and hold them in the ahead position as ef'ectively as the main piston in normal operation. This enables a compact and economical assembly to be obtained.

A particular embodiment of the invention is illustrated in the drawings in which:

FIGURE 1 is a schematic representation of a variable pitch propeller installation, Whilst FIGURE 2 is a longitudinal section on an enlarged scale showing the ram and piston assembly of FIGURE 1.

In FIGURE 1 an engine 6, drives optionally through a clutch 7, the propeller shaft 4, integral with which a cylinder 2, contains a hydraulic main piston 1, attached to the pull and push operating rod 3, within the hollow propeller shaft 4, by the fore and aft motion of which the blades of the variable pitch propeller 5, are caused to take up the desired pitch. Also shown is a locking piston 10, fed with oil or grease by oil passages 9, through non-return valve 8, from manually operable auxiliary oil pump 11 with handle 12.

Referring now to FIGURE 2, hydraulic main piston 1,

in cylinder 2, is operated by oil pressure through the oil passages 14, and 15, from an oil pump (not shown) and a telernotor control valve (not shown) of well known construction. The locking piston or ram, 10, is fitted with sealing rings 13, the emergency oil or grease under high pressure being supplied from pump via non-return valve 8, and passages to the cylinder 16, machined out of the solid intermediate propeller shaft 4.

The description relating to the preferred embodiment and to FIGURES 1 and 2 pre-supposes that the main piston moves toward the propeller in order to move the blades to ahead pitch. In certain cases it may be desirable for the operating piston to move away from the propeller to achieve ahead pitch and in suchcases the emergency ram will be in the form of an annular piston surrounding the operating rod aft of the main piston, or surrounding an extension of the operating rod forward of the main piston.

It is to be understood that the above description is by Way of example only and that details for carrying the invention into effect may be varied without departing from the scope of the invention claimed.

I claim:

1.- In a marine propulsion installation of the type embodying a variable pitch propeller, a propeller shaft, means operably coupled with said propeller for varying the pitch of said propeller, means defining a main cylinder Within said propeller shaft, a piston within said cylinder open-ably connected to said operably coupled means, means for introducing pressure fluid into said cylinder to displace said piston in the desired direction for varying the pitch of the propeller, and-means for the auxiliary activation of the operably coupled means, such means including means defining a further cylinder within said propeller shaft located centrally of and in communication with said main cylinder, a high pressure ram within said further cylinder, means for introducing pressure fluid into said further cylinder at a pressure sufficient to move said ram into engagement with said piston and force said piston to displace said operably coupled means whereby said propeller assumes the ahead position, and non-return valve means associated with the means for introducing fluid into the further cylinder for maintaining the propeller in said last named position.

2. In a marine propulsion installation embodying a variable pitch propeller, a propeller shaft adapted to be driven by a source of power for rotating said propeller, means defining a main cylinder within the propeller shaft, a piston within the cylinder, a pull-push rod displaceably mounted within the propeller shaft operably connected with said propeller and piston respectively for varying the pitch of said propeller, means for introducing pressure fluid into said cylinder to displace said piston and pullpush rod in the desired direction for varying the pitch of the propeller, and means for the auxiliary actuation of the pull-push rod, such means including means defining a further cylinder Within said propeller shaft located centrally of and in communication with said main cylinder, a high pressure ram within said further cylinder, means for introducing pressure fluid into said further cylinder at a pressure suflicient to move said ram into engagement with said piston and displace said piston and pull-push rod to cause said propeller to assume the ahead position, and non-return valve means associated with the means for introducing fluid into the further cylinder for maintaining the propeller in said last named position.

3. The marine propulsion installation as claimed in claim 2, in which said means for introducing fluid into said further cylinder includes an axial passage in the propeller shaft communicating with such cylinder, a radial passage leading from the axial passage to the outside of said propeller shaft, said non-return valve being located in said radial passage, and means connecting said non-return valve to a source of pressure fluid when said propeller shaft is stationary.

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