Drive Mechanism for a Fluke Drive and Method for Installning the Same

The various embodiments of the present invention relate to a drive mechanism for a fluke drive and methods for installing or retrofitting such a drive mechanism onto a vessel, such as a boat.

It is known to use fluke drives on various types of vessels, such as for smaller recreational boats and ships.

It would, however, be desirable to achieve a drive mechanism that is as simple, sturdy and dependable as possible. In particular, such drive mechanisms should be useful together with a conventional propeller drive shaft for a maritime vessel, such as a motorboat, arranged to be propelled by a conventional propeller.

In some embodiments the invention relates to a drive mechanism for a fluke drive, the drive mechanism being arranged to convert a rotary movement into a pivoting movement, the drive mechanism comprising first part; a second part, in turn comprising a second-part engagement means; a third part, in turn comprising a third-part engagement means; and a rod part, in turn comprising a first end and a second end, wherein the second part is rotatable in relation to the first part along a rotary axis which is common to the first part and the second part, wherein the third part is reciprocatingly pivotable in relation to the first part about a first pivot axis which is not the same as the rotary axis, wherein the first pivot axis is fixed in relation to the first part, wherein the second-part engagement means is arranged eccentrically with respect to the rotary axis, wherein the first end engages with the second-part engagement means, and wherein the second end engages with the third-part engagement means.

In some embodiments, the first part is fixed to the hull of a vessel.

In some embodiments, the first part is pivotable in relation to the hull of the vessel about the rotary axis.

In some embodiments, the rotary axis is a main axial direction of a propeller axle of a vessel.

In some embodiments, the rotary axis is the main axial direction of a drive axle being connected via a coupling to a propeller axle of a vessel.

In some embodiments, the second part is directly or indirectly connected to the propeller axle so that the second part rotates with the propeller axle.

In some embodiments, the third part is pivotally connected to the first part, such as via a first rotary bearing, allowing the third part to pivot in relation to the first part about the first pivot axis.

In some embodiments, the second-part engagement means comprises a socket for receiving the first end, the socket having a main longitudinal direction which is slanted in relation to the rotary axis.

In some embodiments, the third-part engagement means is pivotally connected to the second end, such as via a second rotary bearing, so that the second end can pivot in relation to the third part about a second pivot axis.

In some embodiments, the second pivot axis is perpendicular to the first pivot axis.

In some embodiments, the rod part has a main direction of elongation being set at an angle in relation to the rotary axis of at least 8°, such as at least 10°, such as at least 12°. In some embodiments, the rod part has a main direction of elongation being set at an angle in relation to the rotary axis of between 10° and 60°, such as between 10° and 30°, such as between 12° and 24°.

In some embodiments, the third part is connected to a fluke.

In some embodiments, the third part is connected to the fluke via an elongated fluke rod.

In some embodiments, the fluke rod is arranged to describe a pivoting action with a pivot amplitude of at least 8°, such as at least 10°, such as at least 12°, as the second part performs a full rotary revolution about the rotary axis.

In some embodiments, the third part is connected to the fluke via a flexible element comprising a flexible material body, such as a polyurethane body, so that the fluke can pivot in relation to the fluke rod due to the resilience of the flexible body.

In some embodiments, the flexible material body is dimensioned so that a plane of the fluke is parallel to the rotary axis, within +/−10°, when the fluke is driven in water and when the fluke rod is at its maximum/minimum full amplitude pivot position during use at a set cruise operation rotary speed of the rotary axis.

In some embodiments, the flexible material body is cast directly onto the fluke rod and to a fastening means of the fluke so as to resiliently connect the fluke rod and the fastening means of the fluke to each other.

Moreover, in one aspect, the invention relates to a method for installing a drive mechanism of said type. The method comprises providing a vessel having a propeller axle, and mounting the first part to a hull of the vessel and the second part to the propeller axle.

In some embodiments, the method further comprises selecting a flexible material body interconnecting a fluke rod to a fluke of the drive mechanism, the flexible material body being selected with resilient properties so that a main plane of the fluke is parallel to the rotary axis when the fluke is driven in water and when the fluke rod is at its maximum/minimum full amplitude pivot position during use at a set cruise operation rotary speed of the propeller axle.

In some embodiments, the first part is mounted on the hull so that a fluke rod of the drive mechanism pivots in a vertical plane.

In some embodiments, the method comprises mounting two drive mechanisms of said type in parallel; and mounting the respective first part on the hull so that a respective fluke rod of the respective drive mechanism pivots in non-parallel planes or counter-pivots in a common pivot plane.

In some embodiments, the method further comprises connecting the second part to a pivotable drive axle being connected via a coupling to the propeller axle; and providing the first part with a steering mechanism, arranged to pivot the pivotable drive axle in a horizontal plane.

In some embodiments, the installing of the drive mechanism is a retrofitting of the drive mechanism to an already-existing vessel having an already-existing propeller axle, and wherein the method comprises the drive mechanism being installed onto the already-existing propeller axle.

As is shown in, in one embodiment, the present invention relates to a drive mechanismfor a fluke drive. The drive mechanismis arranged to convert a rotary movement, such as coming from a propeller axle(see) into a pivoting movement, such as of a fluke, which can be a flexible fluke. The conversion can take place along the same main axis.

For achieving this conversion, the drive mechanismcomprises a converter. The converter, in turn, comprises a first part, a second partand a third part.

It is noted that the details of the drive mechanismillustrated in the Figures are exemplary, and that the convertercan be implemented also together with other mechanisms for transferring the resulting pivoting movement to a fluke.

Furthermore, in the example shown in the Figures, the first partis fastened, or arranged to be fastened, to a structure, such as a fixed structure or to the hullof a vessel(see), whereas the third partis fixedly fastened, or arranged to be fixedly fastened, to the fluke rodor the fluke. Hence, the third partcan be connected directly or indirectly to the fluke, such as indirectly connected via the fluke rod.

This means that the second partrotates whereas the third partinstead pivots. It is, however, realised that it would be possible to provide the converterso that a pivoting second partwould instead be correspondingly connected to the fluke rodor the fluke, whereas a rotating third partwould be correspondingly connected to said structure. In the latter case, the first partwould be coaxial with the second partjust like in the first case, but then also pivot together with the fluke rod. In the following, the converterwill, for clarity, be described in the former configuration which is shown in the Figures, but it is realised that the corresponding applies in case the second partand the third partare switched.

The fastening to the structure can be a rigid or a non-rigid (such as pivotal) fastening to the structure.

is a detailed view of the converterfrom the above and from the side where the propeller axleenters into engagement with the converter.

is a different detailed view from a perspective roughly opposite to that shown in.

As is perhaps most clearly shown in, which is a partly removed cross-sectional side view of the converter, the second partcomprises a second-part engagement means and the third partcomprises a third-part engagement means.

Moreover, the convertercomprises a rod part, for instance in the form of an elongated stiff part arranged to transfer at least compressive and shear forces along and perpendicular to its length.

The rod partin turn comprises a first end, arranged to engage with the second-part engagement means, and a second end, arranged to engage with the third-part engagement means.

The second partis rotatable in relation to the first partalong a rotary axis(see). The rotary axisis common to the first partand the second part.

In contrast thereto, the third partis reciprocatingly pivotable, that is pivotable back and forth on either pivotal side of a pivotal center orientation, in relation to the first part. The pivoting occurs about a first pivot axis(again, see). The first pivot axisis not the same as, in other words does not coincide with, the rotary axis. In some embodiments, the first pivot axisis not parallel with and/or does not intersect the rotary axis. Said pivoting can be arranged to take place only in a pivot plane, which may be vertical, horizontal or inclined.

As is illustrated in the Figures, the first pivot axisis fixed in relation to the first part, such as defined by one or several cooperating pivot points on the first part. In other words, the third partcan be pivotally connected, via such one or several cooperating pivot points, to the first part. When the first partis fastened to said structure, it will then define the first pivot axisin relation to the structure. In case the first partis rigidly connected to the structure, the first pivot axiswill also be rigid in relation to the structure, but if the first partis movable (such as pivotally fastened) in relation to the structure, the first pivot axiswill be correspondingly movable in relation to the structure.

Hence, the third partcan be pivotally connected to the first part, allowing the third partto pivot in relation to the first partabout the first pivot axis. This pivoting can be defined by said one or several pivot points. The pivot points may in turn be defined by one or several first rotary bearings. As is shown in the Figures, the pivot points can comprise two first rotary bearingsarranged along said first pivot axis, such as on or at opposite external side walls of the first part.

In the embodiments shown in, the first partis fastened to the structure in an orientation so that the flukepivots upwards and downwards, along a vertical pivot plane. It is, however, realized that the first partcan instead be fastened to the structure in an orientation such that the flukepivots from side to side along a horizontal pivot plane; or the pivot plane can slant. In some embodiments, the first partis pivotally fastened in relation to the structure, such that it can pivot about the rotary axis. Then, the pivot plane can be dynamically adjusted (rotated), such as in response to varying modes of operation or operation conditions.

As is best seen in, the second-part engagement meansis arranged on the second parteccentrically with respect to the rotary axis. In other words, the second partrotates with the propeller axleand as a result the second-part engagement meansrotates along with the rest of the second part. As the second-part engagement meansis eccentrically arranged on the second partin relation to the rotary axis, the second-part engagement meanswill describe a circular movement path about the rotary axis. Since the first endof the rod partengages with the second-part engagement means, the first endis also forced to describe such circular movement path. The radial distance of the second-part engagement meansfrom a centre of rotation of the second partcan be at least 5 cm, and in some cases much more for large ships and the like.

The second partcan be rigidly connected to the propeller axle, such as via a screw joint or other suitable joining means.

In some embodiments, the rotary axisis the main axial direction of the propeller axleof the vessel. The vesselmay be an already-existing vesselhaving an already-existing propeller axle, and the drive mechanismcan then be a retrofitting of the drive mechanism, such as for converting an existing propeller drive into a fluke drive. In such cases, a gear box can be added between the propeller axleand the drive mechanism, even if a length of the fluke rodand/or a property (such as a size, a shape and/or a resilience) of the flukecan instead be adapted so that desired operation properties are achieved without using a gear box but instead connecting the propeller axledirectly to the first part.

As is understood from the above, the second partcan be directly or indirectly connected to the propeller axleso that the second partrotates with the propeller axleand in turn drives the first endof the rod partalong said eccentric circular path.

The second-part engagement meanscan comprise a socketfor receiving the first endof the rod part. In such cases, the sockethas a main longitudinal direction which is slanted in relation to the rotary axis, and that can be roughly or completely parallel to a main longitudinal direction of the rod part.

The socketand the first endcan hence comprise cooperating engagement means, that can comprise a third rotary bearingallowing the rod partto rotate about its longitudinal direction in relation to the socket. This is illustrated in. However, since the rod partand the socketwill be in the same relative angular orientation in relation one to the other as the second partrotates about the rotary axis, the first endcan alternatively simply rest in the socketin an engagement allowing the rod partto rotate about its longitudinal direction in relation to the socket. The second endcan then be fastened to the third partin a way not allowing any rotating about the longitudinal direction of the rod partin relation to the third part. Alternatively, the second endcan engage with the third partin a corresponding way allowing such relative rotation whereas the first endis rigidly connected to the second part. In yet further alternative embodiments, both the first endand the second endcan engage with the second partand the third part, respectively, in a way allowing such rotary movement about the longitudinal direction of the rod part. It is also possible that the rod partengages in a way not allowing such relative rotation at either of the first endand the second end, but that the rod partinstead comprises two parts that are connected one to the other in a way allowing them to rotate relative to each other about the longitudinal direction of the rod partwhereas the first endand the second end, being formed at either of said two parts of the rod part, are connected to the second partand the third part, respectively, in a way not allowing such relative rotation.

Even in case the first endand/or the second endof the rod partsimply rests in a respective socket(of the second partand/or the third part, respectively), the rod partcan be kept in place between the second partand the third partby the second-part engagement meansof the second partand the third-part engagement meansof the third part; by the first partand the third partbeing kept together by said pivotal connection; and ny the first partkeeping the second partin axial position (with respect to the rotary axis) in relation to the third part. In order to guarantee the latter axial position, the first partcan comprise a shoulderor similar means to limit the rotary axisaxial freedom of movement of the second partin relation to the third part. The first partcan also comprise an axially extending cavity in which the second partis accommodated, allowing it to rotate but not move radially in relation to the rotary axis. As shown in, the second partmay engage with the first partvia an axle bearing.

As is furthermore best understood from,and, the third-part engagement meanscan be pivotally connected to the second endof the rod part. It is noted that this pivotal connection may not allow rotating of the rod partabout its longitudinal direction, but instead only allow pivoting in a pivot plane to which said longitudinal direction is parallel or roughly parallel. The pivotal connection may be embodied via a second rotary bearing, being arranged so that the second endcan pivot in relation to the third partabout a second pivot axis. The second pivot axiscan be perpendicular to the first pivot axis.