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Patent Searching and Data


Title:
MARINE PROPELLER UNIT
Document Type and Number:
WIPO Patent Application WO/1998/029300
Kind Code:
A1
Abstract:
A contra-rotating propeller unit has two sets of propellers (8, 39) driven in opposite directions, respectively by a single drive shaft (2). One set of propellers (8) is directly driven by the shaft (2) which passes through a carrier (12) attached rigidly and immediately behind a stern tube (1) of a ship. The other set of propeller blades (39) is carried by a ring (41) which is axially displaceable along a propeller hub (35) to vary the spacing between the two sets of propellers. The hub (35) has a skirt (34) supporting a sealed bearing (36) confining oil to the interior of the unit while allowing controlled variation of the spacing between the unit and the stern tube (1). A reversing drive to the hub (35) is achieved by a pinion (23) supported in the carrier (15) and driven from the shaft (2) by external gearing (30) while driving the hub (35) through internal gearing (33). The mounting of the pinion (23) in the carrier (12) and the attachment of the carrier (12) to the stern tube, gives a mechanically strong arrangement less prone to vibration than prior art proposals.

Inventors:
Gillies, Donald Alexander (3/3 Brunton Place, Marsfield, NSW 2122, AU)
Application Number:
PCT/AU1997/000886
Publication Date:
July 09, 1998
Filing Date:
December 24, 1997
Export Citation:
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Assignee:
HEADLAND SECURITIES PTY. LTD. (56 Headland Road, Castle Cove, NSW 2069, AU)
Cameron, Ron (9 Court Road, Double Bay, NSW 2028, AU)
Gillies, Donald Alexander (3/3 Brunton Place, Marsfield, NSW 2122, AU)
International Classes:
B63H5/10; (IPC1-7): B63H5/10
Domestic Patent References:
WO1996009954A11996-04-04
WO1985005085A11985-11-21
Foreign References:
US4540369A1985-09-10
Attorney, Agent or Firm:
Rantzen, Henry John (85 John Street, Woollahra, NSW 2025, AU)
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Claims:
CLAIMS:
1. A marine propeller unit having two propellers (39, 8) with their respective hubs (35,3) coaxially arranged on a single propeller drive shaft (2) attached to one (3) of the hubs and driving the other hub (41) through a reversing gearing which includes a doubleended driving pinion (23) having its axis of rotation extending parallel to, but displaced from the axis of the propeller drive shaft (2), the pinion (23) being supported by a carrier (12) adapted to provide a rigid extension of the ship's stern tube or frame (1) and being located directly astern of it, and being arranged to transmit rotational drive from external gearing (30) driven by the shaft (2) to internal gearing (33) on said other hub (35).
2. A unit as set forth in claim 1, in which the forward set of propeller blades (39) is mounted on a ring (41) which is axially movable along its hub to different positions at the the ring can be fixed, to enable the spacing between the two sets of propeller blades (39, 8) to be varied during assembly of the unit.
3. A unit as set forth in claim 1 or claim 2, in which the carrier (12) has a cylindrical surface arranged concentrically within a skirt (34) which carries a bearing (36) providing an oiltight seal between the carrier (12) and the skirt (34) while allowing relative axial movement between them during setting up of the unit to enable an optimum spacing to be achieved between the stern tube (1) of the vessel and the two sets of propeller blades (39, 8).
4. A unit as set forth in any one of the preceding claims, in which the carrier (1 2) is formed in two portions (15,16) interconnected by bolts, (17) one portion (16) supporting the pinion (23) and the other portion (15) being adapted to be rigidly attached to the stern tube (1) of the vessel.
Description:
MARINE PROPELLER UNIT FIELD OF THE INVENTION THIS INVENTION relates to a contra-rotating marine propeller unit and is more specifically, although not exclusively, concerned with modifying or improving the contra-rotating propeller unit described and claimed X co-pending published International Patent Application No. WO 96/09954 published on 4th. April 1 996.

STATE OF THE ART In the above international patent application is described and claimed a contra-rotating propeller unit which is of robust construction, has relatively few moving parts and has two co-axial propeller hubs driven from a single propeller shaft in opposite directions, respectively.

OBJECT OF THE INVENTION An object of this invention is to provide an improved contra-rotating propeller unit.

THE INVENTION In accordance with the present invention a marine propeller unit has two propellers with their respective drive hubs coaxially arranged on a single propeller drive shaft attached to one of the hubs and driving the other hub through a reversing gearing which includes a double-ended driving pinion having its axis of rotation extending parallel to, but displaced from the axis of the propeller shaft, the pinion being supported by a carrier adapted to provide a rigid extension of the ship's stern tube or frame and located directly astern of it, and being arranged to transmit intentional drive from external gearing driven by the shaft to internal gearing on said other hub.

An advantage of the arrangement of the present invention is that the pinion through which drive is transmitted between the two hubs is supported close to the stern tube or frame, rather than being spaced from it by one of the hubs as is disclosed in the arrangement of the said International Patent Application. A stronger and more compact configuration of the parts of the propeller unit is thus obtained, and the manufacture and assembly of the unit is simplified. These advantages are of significant importance in marine vessel construction and operation.

PREFERRED FEATURES OF THE INVENTION Preferably the hub adjacent the carrier is provided with a cylindrical skirt which extends forwardly and closely surrounds a cylindrical portion of the carrier. A sealed bearing may be provided between the skirt and the carrier cylindrical portion to allow limited movement of the hubs axially of the propeller shaft while retaining meshing engagement of the double-ended pinion with the gearing at its opposite end-portions.

Also, the forward propeller may be mounted on a ring on the skirt, the ring being movable along the skirt to a desired position in to which it can be fixed in order to achieve a desired operational spacing between the two sets of propeller blades. This enables the performance spacing to be altered for a given propeller installation to achieve the optimum working performance.

INTRODUCTION TO THE DRAWING The invention will now be described in more detail, by way of example, with reference to the accompanying partly diagrammatic drawing which shows a vertical side section through a contra-rotating propeller unit attached to a stern tube or frame of a vessel.

DESCRIPTION OF PREFERRED EMBODIMENT A marine vessel (not illustrated) has a frame or stern tube 1 through which protrudes a propeller shaft 2 having a propeller hub 3 rigidly attached to it by splines 4 and held in place by a lock nut 5 screwed onto a threaded tail 6 of the shaft. A fairing 7 encloses the

nut 5 and engages the periphery of the hub 3 as shown. One of a set of propeller blades is attached to the hub 3, as is partially shown at 8.

A locating plate 10 is bolted securely to the end of the stern tube 1 and carries a ring of circumferentially-spaced dogs 11. A carrier 1 2 is provided at its forward end with a complementary ring of dogs 1 3 which interfit tightly with the dogs 11 to restrain the carrier 1 2 against radial and circumferential movement with respect to the plate 10 and thus the shaft 2.

The carrier 1 2 is supported internally on the shaft 2 by a bearing bush 1 4 and has two axially-spaced portions 1 5 and 1 6 which are held together by a ring of bolts one of which is shown at 28. The portions 1 5 and 1 6 are formed with respective aligned journals 18 and 20 in which locate respective shaft portions 21 and 22 of a double- ended drive-transmission pinion 23 providing two axially-spaced gear portions 24 and 25. Normally a number of such pinions 23 are similarly mounted on the carrier 1 2 at equi-angularly spaced positions around the axis of the propeller shaft 2. The gear portion 25 is keyed at 26 to a cylindrical stem 27 of the double-ended pinion 23 and held in place by a nut 28 screwed onto a threaded end of the stem 27. Thus the gear portion 25 may be considered as being, and as functioning as an integral component part of the pinion 23.

The gear portion 24 of the pinion 23 meshes with an external gear 30 keyed to the propeller shaft 2 at 32 so as to rotate with it. The other gear portion 25 meshes with an internal ring gear 33 provided internally on a second propeller hub 35 journalled to the shaft 2 between the rear of the carrier 1 2 and the forward end of the hub 3 so as to be able to rotate on the shaft 2. A cylindrical skirt 34 extends forwardly over the outside of the carrierl 2 from the second hub 35, and is supported at its forward end on

the carrier by a sealed bearing 36. The second hub 35 has an external keyway 40 permitting axial adjustment of a propeller ring 41 along the skirt 34 to different positions into which it can be fixed by means (not shown). The ring 41 carries a second set of propeller blades one of which is shown at 39. The keyway 40 allows the axial position of the ring 40 to be set, during assembly of the unit, to a position which achieves the optimum spacing between the two sets of propeller blades to provide the best performance. The ring 41 is then locked in that position by means (not shown).

Likewise the permitted axial movement of the skirt 34 over the outside of the carrier 1 2, allows the spacing between the stern tube 1 of the vessel and the two sets of propeller blades 8 and 39, to be varied to achieve an optimum value. This spacing can then be fixed by further means (not shown).

A pair of radially-spaced sealed thrust bearings 37 and 38 are located between the two hubs 3 and 35 to complete the assembly of the propeller unit. The internal cavity of the unit containing the gearing contains oil under pressure for lubrication purposes. It is retained by the sealed bearing 36. Additional means (not shown) are provided to prevent any small axial displacements of the hub 35 with respect to the carrier 1 5 while allowing rotation of the hub 35 to occur when the unit is operating.

OPERATION OF PREFERRED EMBODIMENT During operation of the propeller unit described, drive from the shaft 2 rotates the propeller hub 3 in one direction and is also transmitted through the external drive gear 32 to the set of double-ended pinions 23 to drive them in the reverse direction of rotation. As these pinions engage the internal ring gear 33 of the second hub 35, this also is driven in the reverse direction so that contra-rotation of the two propeller hubs 3 and 35 is achieved.

The above-described construction of propeller unit has the following advantages. It is simple to manufacture and assemble. It avoids the use of long bolts to secure the carrier to the stern tube of the vessel and is therefore potentially more robust. It allows the spacing between the two propellers to be varied easily so that an optimum spacing can be achieved without having to alter other components of the unit. There is less operational vibration as the moving parts of the unit are located nearer to the vessel's stern tube.

Finally the optimum spacing between the stern tube and the propellers can be varied to suit the characteristics of the particular vessel to which the propeller unit is fitted.

MODIFICATIONS OF PREFERRED EMBODIMENT In one modification of the above described arrangement, the two sets of dogs 11 and 1 3 are dispensed with and a set of bolts (not shown) are used to attach the unit directly to the stern tube.

In a further modification, the blades have their root portions mounted in a hydraulically operated mechanism which enables the individual blades to be rotated about their longitudinal axes to different angles. This enables the driver of the propeller unit to be varied between ahead and astern, without altering the direction of rotation of the shaft 2.