WO1989010298A1

WO1989010298A1 - Driving device for the propulsion of waterborne craft

Info

Publication number: WO1989010298A1
Application number: PCT/SE1989/000228
Authority: WO
Inventors: Majvor Baglien
Original assignee: Majvor Baglien
Priority date: 1988-04-22
Filing date: 1989-04-21
Publication date: 1989-11-02
Also published as: SE8801523L; SE8801523D0; AU3531489A

Abstract

The invention relates to a driving device for the propulsion of waterborne craft, said driving device having a propulsion unit which comprises at least one endless flexible belt or chain element (8) having driving projections and arranged between a pair of separate guide rollers or guide parts (9, 9'), at least one (9) of which is rotatably drivable, said belt element having upper and lower parts (11, 10), of which the lower (10) is adapted to be held in engagement with the water surface so as to propel the craft. The propulsion unit (8) is adapted to be supported at the lower part of a mounting (4) which extends up to one or more attachments (5) for attaching the mounting and, thus, the driving device in its entirety to the craft, the only connection between the propulsion unit and the craft being the mounting and the attachment.

Description

DRIVING DEVICE FOR THE PROPULSION OF WATERBORNE CRAFT

The present invention relates to a driving device for the propulsion of waterborne craft, said driving device having a propulsion unit which comprises an endless flexible belt or chain element having driving projections and arranged between a pair of separate guide rollers or guide parts, at least one of which is rotatably drivable, said belt element having upper and lower parts of which the lower is adapted to be held in engagement with the water surface so as to propel the craft.

A driving device of the type mentioned above is disclosed in FR patent specification 1,351,529. In this prior art driving device, the driving belt is however mounted in a frame whose front end is fixedly connected with the hull of the craft, viz. via a joint, while the rear end of the frame is suspended in a vibration-absorbing device which comprises a spring arrangement and hydraulic shock absorbers. This means that the driving device can be used only for craft which have been especially designed to fit the driving device. The driving device thus is not universally useful for different types of hull. Besides, the driving device according to FR 1,351,529 is mounted in a position that is fixed once and for all, which makes it necessary to steer the craft by means of a separate rudder.

The present invention aims at providing a driving device which is universally useful for different types of craft and which in itself can steer the craft without assistance from any separate rudder. According to the invention, this is achieved in that the propulsion unit is adapted to be supported at the lower part of a mounting which extends up to one or more attachments for attaching the mounting and, thus, the driving device in its entirety to said craft, the only connection between said propulsion unit and said craft being the mounting and the attachment.

A considerable advantage of the inventive driving device is that the actual propulsion unit can be used to steer the craft, either in that the unit is pivoted relative to the craft, or in that two different driving belts are caused to operate at different propulsion speeds. Since the propulsion unit is supported by a mounting, the driving device in its entirety can be mounted on any desired type of hull. A further advantage is that the driving belt or belts will serve as a hydrofoil, which helps to hold the moving craft in a comparatively elevated position in the body of water in which the hull of the craft has a minimal frictional resistance to water. Analogously, the driving belt itself will lie high in the body of water and since it has no components whatsoever extending deep into the body of water, such as a propeller housing in outboard motors provided with a propeller, an extremely effective driving power is obtained in that only the operative lower part of the driving belt engages with the water surface. As a result, every risk that the driving device itself strikes ground is at the same time eliminated. There is not even a risk of striking ground that lies extremely close to the water surface. The invention will be described in detail with reference to the accompanying drawing in which: FIG. 1 is a schematic side view of an inventive driving device connected to a boat, FIG. 2 is an end view from behind of the same device, and FIG. 3 is a top plan view illustrating different pivotal positions of the device. The drawing illustrates a driving device which in its entirety is designated 1 and is connected to the stern of a boat designated 2, in particular of small size. In the embodiment exemplified, the device 1 is an outboard motor which in known manner comprises a motor casing 3 and a mounting 4 extending downwardly therefrom and comprising one or more attachments 5 for attaching the device to the boat. At the lower part of the mounting 4, there is arranged a propulsion unit 6 which does not consist of a propeller as in connection with conventional outboard motors but instead consists of at least one endless flexible belt or chain element 8 having driving projections 7 and arranged in per se known manner between a pair of separate guide rollers or wheels 9,9', at least one of which is drivable via a transmission (not shown) included in the mounting. The endless driving belt 8 thus comprises upper and lower parts 10,11 of which the lower part 10 is adapted to be held in engagement with the water surface so as to propel the boat. In the example shown, the device 1 comprises two substantially identical driving belts 8,8' arranged on opposite sides of the mounting 4 which extends vertically downwards, two casings 12,12' being connected with the mounting and covering the upper part of the driving belt and the guide wheels 9,9', said casings being down¬ wardly open and comprising means for mounting the axles of the guide wheels or rollers. These axles are in turn inserted with their one end into the mounting and are there connected with a suitable mitre gear or worm gear which is, in turn, connected with a vertical drive shaft which is conventionally included in the mounting and associated with the motor. Each of the front guide rollers 9 of the two driving belts 8,8' thus are rotatably drivable by the motor which is accommodated in the casing 3 and advantageously consists of a conventional internal combustion engine, for example a petrol engine.

As is clearly seen in Fig. 1, the only connection between the mounting 4 (and thus the driving device in its entirety) and the hull of the boat 2 consists of the attachment 5, which means that the driving device can be mounted on many different types of boat without necessitating any modification of their hulls or a special design to fit the driving device.

According to a preferred embodiment of the invention, there is arranged, in the space between the upper and lower parts 11,10 of the driving belt 8, a body 13 which fills up at least the main part of said space so as to prevent water from flowing through the space. This filling body can advantageously comprise a metal sheet shell. The length of the filling body should be as great as the distance between the rotatable wheels or rollers 9,9', while its width is approximately as great as the length of the wheels or the width of the belt, its height or thickness being as great as the diameter of the wheels. In practice, this diameter can be in the range of 100-200 mm, preferably about 150 mm. The distance between the front and rear wheels 9,9' should be at least about 400 mm, while the width of the individual belt can advantageously vary in the range of 150-300 mm. The front and rear ends of the filling body 13 conveniently have rounded recesses matching the circular circum- ference shape of the wheels 9,9".

The two driving belts 8,8' should in practice be adjustably movable and lockable in different positions relative to the water surface. Thus, the driving belts should be adjustable not only in the vertical direction relative to the craft 2, but also at different, desired angles relative to the plane of the water surface, in that the belts should be adjustable in positions in which they are at least slightly inclined upwards-forwards in the driving direction. The adjustability of the driving belts can be realised in various ways. One way is to make the casings 12 in which the belts are mounted, adjustable and lockable relative to the mounting 4. A further way is to permanently connect the casings with the mounting and make the mounting adjustable at different angles relative to the mounting 5 which is used for mounting the driving device on the craft. It is further conceivable to make the driving belts adjustable and lockable in the vertical direction relative to the mounting or, alternatively, to make the mounting adjustable and lockable relative to the attachment 5.

The driving direction of the driving wheels of the belt 8 suitably is reversible, such that the driving belts may be caused to drive the craft either forwards or backwards. The steering of the craft can be realised in various ways. In the example shown, the mounting 4 is intended to be rotatable relative to the attachment 5, so as to pivot the driving device in its entirety at a desired angle in relation to the keel line of the craft. A further way is to provide the two driving belts 8,8 with separate drive means, such that the belts can be driven at various speeds and/or in different driving directions, whereby the steering can be effected by variation of the_*, driving speeds and driving directions, respectively.

Although the inventive driving device can advan¬ tageously be designed to resemble an outboard motor, i.e. an internal combustion engine arranged directly on the mounting, the propeller being replaced by one or more endless driving belts or chains as described above, the driving device can also be designed with the actual driving source or engine positioned inboard, at the same time as the necessary power transmission to the driving belts occurs via suitable transmissions, for example in the form of hydraulic conduits from the driving source to a hydraulic motor arranged on the mounting, for example a hydraulic motor positioned midway between the two driving wheels or rollers 9 or, alternatively, inside a single driving roller for driving a single driving belt.

It should also be emphasised that the two wheels of each driving belt can be designed with different diameters, more precisely in such manner that the sternmost wheel has a larger diameter than the one ahead, so that the lower part of the belt can be inclined.

Claims

1. A driving device for the propulsion of waterborne craft, said driving device having a propulsion unit which comprises at least one endless flexible belt or chain element (8,8') having driving projections (7) and arranged between a pair of separate guide rollers or guide parts (9,9'), at least one (9) of which is rotatably drivable, said belt element having upper and lower parts (11,10), of which the lower (10) is adapted to be held in engagement with the water surface so as to propel the craft, c h a r a c t e r i s e d in that said propulsion unit (8,8' ) is adapted to be supported by the lower part of a mounting (4) which extends up to one or more attachments (5) for attaching the mounting and, thus, said driving device in its entirety to said craft, the only connection between said propulsion unit and said craft being said mounting (4) and said attach¬ ment (5 ) .

2. The driving device as claimed in claim 1, c h a r a c t e r i s e d in that said driving belt element (8) is adjustably movable and lockable in different positions, particularly angular positions relative to said mounting and/or said attachment (5).

3. The driving device as claimed in claim 1 or 2, c h a r a c t e r i s e d in that it comprises two endless driving belts (8,8'), one on each side of said mounting (4).

4. The driving device as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the driving direction of said belt (8,8') is reversible.

5. The driving device as claimed in claim 3, c h a r a c t e r i s e d in that the two driving belts are individually drivable at variable speeds.

6. The driving device as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that there is arranged, in the space between the upper and lower parts (11,10) of said driving belt, a body (13) which fills up at least the main part of said space so as to prevent water from flowing through said space.

7. The driving device as claimed in claim 6, c h a r a c t e r i s e d in that the length of the filling body is as great as the distance between the two guide wheels or rollers (9,9' ), that its width is at least as great as the length of said wheels or the width of said belt (8), and that its height or thickness is as great as the diameter of said wheels.

8. The driving device as claimed in claim 6 or 7, c h a r a c t e r i s e d in that the front and rear ends of said filling body (13) have rounded recesses matching the circular circumference shape of said wheels .

9. The driving device as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that said driving belt(s) (8,8' ) are pivotable relative to said attachment(s ) adjacent to said craft, for example in that said mounting (4) is rotable relative to said attachments (5) and said driving belts are stationarily connected with said mounting.

10. The driving device as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the individual driving belt is built into a casing (12) which is connected with said mounting (4) and covers the upper part of the driving belt, said casing being open downwardly and comprising at least one side wall which serves as a bearing and/or carrier for said guide rollers or wheels (9,9' ).