AU597116B2 - Improvements to marine drive apparatus - Google Patents

Description

r '.4y°.k.LATTACHED MAIL OFFICER... COMMC. EALTH OF AUSTRALIA FORM CL E T

COMPLETI

PATENTS ACT 1952 R PECI T FICATI ON I FOR OFFICE USE: Class Int.Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: 9 9 Priority: Related Art: 4

L

Name of Applicant: Address of Applicant: Actual Inventor: GEOFFREY BRUCE DOUGLAS Flat 2, Unit 10, Begley Street, Airlie Beach, Queensland, Commonwealth of Australia Geoffrey Bruce Douglas Address for Service: SHELSTON WATERS, 55 Clarence Street, Sydney Complete Specification for the Invention entitled: "IMPROVEMENTS TO MARINE DRIVE APPARATUS" The following statement is a full description of this invention, including the best method of performing it known to me/us:- Complete of 62958/86 dated 19th September, 1986 This document contains the amendments made under Section 49 and is correct for I prhting.

LODGED AT SUB-OFFICE 1 8 SEP 187 I Sy S 4S ny. The present invention relates to marine drive apparatus and is directed to achieving reverse thrust as well as steerage.

Conventionally, marine drive apparatus of the shaft and pitched propeller type achieve reversibility by complex mechanisms reversing the rotation of the propeller. A durable apparatus of this type may be of undesirable bulk and weight for certain applications.

Steerage requires a separate rudder means.

It is an object of the present invention to provide reversible, steerable thrust by a relatively simple, light weight and durable means.

According to the invention there is provided a marine drive apparatus for a water craft, said apparatus including a reversing and steering channel at least partly shrouding a rotatable propeller so as to direct the flow of water produced by said propeller, said channel when positioned to provide forward drive having spaced side walls joined by a roof portion and being rotatable about a first axis to provide steerage, characterised in that said steering channel is additionally rotatable about a second axis to move said roof portion aft of said propeller such that said channel can intercept and deflect said flow, thereby to provide reverse thrust, said channel being selectively rotatable about said first and second axes.

Preferably said roof portion includes inwardly directed deflection means located at least at its aft end for providing increased reverse thrust.

-2- A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:- Figure 1 is a part sectioned side elevation of a marine drive apparatus according to the invention, showing the channel positioned for ahead propulsion.

Figure 2 is a schematic view of the channel configuration shown in Figure 1.

Figure 3 is a forward looking end view of the apparatus shown in Figure 2.

Figure 4 is a view similar to Figures 1 and 2 but illustrating the channel rotated to its position for providing reverse thrust.

"r "Figure 5 is a plan view of the astern propulsion configuration illustrated in Figure 4.

o "0 Referring to the drawings, the marine drive apparatus SI 1 is shown attached to a propeller shaft housing 2 by a wedge-shaped mounting bracket 3. The propeller 4 may be of the surface-piercing type such that the vessel operates between a low speed water level approximately at 5 and a high speed water level ap.roximately at 6.

i* The drive includes a channel 7 having spaced side i l walls 8 and 9 joined by a roof portion 10. The channel 7 is selectively rotatable about a first, substantially vertical axis 11 and a second substantially horizontal axis 12 in a manner to be described hereinafter.

The channel 7 partly shrouds the propeller 4 so as to direct the flow of water and control the direction of 3 0 1 l

A"

21 c

J

i

A,

A

9 A 4 4 a motion. Rotation about the substantially vertical axis 11 provides steerage while rotation about the substantially horizontal axis provides reverse thrust by moving the channel from the forward configuration shown in Figures 1 to 3 to the reverse configuration shown in Figures 4 and In the reverse configuration it can be seen that the roof portion 10 has been moved to a position aft of the propeller 4 such that the channel 7 can intercept and deflect the flow and provide the required reverse thrust.

The provision of inwardly directed d3flection vanes 12 assists in diverting the flow of water and increasing the reverse thrust.

The desired channel rotation about the two axes can be achieved by any suitable means. One preferred form is illustrated somewhat schematically in Figure 1.

In this embodiment, the drive is supported by a 4 central bearing sleeve 16 rigidly secured to the mounting so bracket 3 by a rearwardly cantilevered support arm 17.

Rotatably mounted within the bearing sleeve 16 and coaxial with the substantially vertical steering axis 11 is a o cylindrical rudder post 18 rigidly connected at its top end with a transverse support beam 19. A steering arm extends forwardly from the support beam 19. Conventional steering means attached to the steering arm will then rotate the transverse support beam about the axis 11.

Each end of the transverse support beam 19 is rigidly connected to a downwardly extending channel pivot arm 21.

The lower end of each pivot arm 21 is pivotably engaged *5 It 4 F f i 1--3 with a pin 22 rigidly secured to the channel side wall 8 by bracket 23.

It will be appreciated that Figure 1 illustrates the port pivot arm 21 engaging the port channel side wall 8.

An unseen but symmetrically identical configuration appears on the starboard side of the support beam 19 such that the pair of coaxial pivot pins 22 define the substantially horizontal axis 12.

Each channel side wall bracket 23 also carries a rigid crank arm 24. A port tilt link 25 and a starboaid tilt link 26 are each pivotably engaged with their respective crank arms by coaxial pivot pins 27. The crank arms may be replaced with pivot pins 27 connected directly to the channel in the same manner as pivot pins 22.

The upper end of each tilt link is connected to a a cross bar 28 by hinge pins 29. The centre of the cross Sbar is connected with a piston rod 30 and piston 3. which slides in a cylinder 32 defined by the inner surface of the rotatable rudder post 18. Hydraulic fluid is supplied by conventional means to the required opposite sides of the piston 31 via valving ports (not shown) through the i walls of the bearing sleeve 16 and rudder post 18. Three 0O-ring seals 14 are respectively located between the central bearing sleeve 16 and the cylindrical rudder post 18 at the centre and opposite ends of the rudder post as shown. The seals separate the flow of hydraulic fluid through the ports respectively located between the three seals.

5 i I Actuation of the piston 31 raises or lowers the cross bar 28 which in turn moves the tilt links and rotates the channel as previously described about its substantially horizontal axis 12. This rotation is obtained without interference with the steering function achieved by rotation about the substantially vertical axis 11. This axis may be vertical or suitably inclined as shown.

There is no need for the steering axis to be permanently fixed with respect to the water craft. In other embodiments the channel may be rotably mounted to an arm which itself rotates about the reversing axis. In this embodiment the steering axis is fixed when the drive apparatus is in its forward drive configuration, but rotates with the channel when the arm moves the channel to the reverse thrust configuration.

Although the invention has been described with reference to specific examples it will be appreciated that the invention may be embodied in many other forms.

I

C I I 1

(CC

6

Claims (10)

1. A marine drive apparatus for a water craft, said apparatus including a reversing and steering channel at least partly shrouding a rotatable propeller so as to direct the flow of water produced by said propeller, said channel when positioned to provide forward drive having spaced side walls joined by a roof portion and being rotatable about a first axis to provide steerage, characterised in that said steering channel is additionally rotatable about a second axis to move said roof portion aft of said propeller such that said channel can intercept and deflect said flow, thereby to provide reverse thrust, said channel being selectively rotatable about said first and second axes.

2. A marine drive apparatus according to Claim 1 wherein Ssaid roof portion includes inwardly directed deflection lit means located at least at its aft end for providing Lincreased reverse thrust.

3. A marine drive apparatus according to Claim 2 wherein said deflection means comprises a pair of vanes respectively located at the forward and aft ends of said roof portion.

4. A marine drive apparatus according to Claim 1 wherein said first axis is defined by a cylindrical rudder post rotatably mounted to a coaxial bearing adapted for rigid attachment to said water craft A marine drive apparatus according to Claim 4 wherein rotation about said second axis is achieved by an hydraulically actuatable piston coaxial with said rudder post. 7 I

6. A marine drive apparatus according to Claim 5 wherein said piston connects with a transverse cross bar pivotably connected at its opposite ends with respective links in turn pivotably connected at their opposite ends to coaxial pivot points on said channel spaced from said second axis.

7. A marine drive apparatus according to Claim 1 wherein said first and second axes do not intersect.

8. A marine drive apparatus according to any one of Claims 1 to 7 wherein said first axis is vertical.

9. A marine drive apparatus according to any one of claims 1 to 7 wherein said first axis is inclined from the vertical. A marine drive apparatus according to any one of the preceding claims wherein said second axis is substantially horizontal.

11. A marine drive apparatus according to any one of the e preceding claims wherein said first axis is fixed with I I tit respect to said water craft.

12. A marine drive apparatus according to any one of the preceding claims wherein said roof portion when in its forward drive position rides clear of the water once the water craft gains some forward speed. I S- 13. A marine drive apparatus substantially as herein described with reference to the accompanying drawings. DATED this day of 1990. GEOFFREY BRUCE DOUGLAS Attorney: WILLIAM S. LLOYD Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS 8