Folding propeller

Abstract

A folding propeller for a boat, e.g., for a sailboat or a multihull yacht, and a method for installing and/or adjusting such a folding propeller, where said folding propeller has a hub for directly or indirectly fastening at a driveshaft connected to a motor, where said folding propeller further has at least two individual blades, where each of said blades has a root arranged to pivot around a pivot pin at said hub to be either in a first, operative position, where the blades are pointing mainly in a radial direction, and in a second, inoperative position, where the blades are pointing mainly in an axial direction, where said hub has one or more cut outs for said blades roots and further has a first set of holes for installing said pivot pins and a second set of holes for installing a locking device for engagement with said pivot pins.

Claims

1. A folding propeller for a boat, where said folding propeller comprises a hub for at least indirectly fastening at a driveshaft connected to a motor, where said folding propeller further comprises at least two individual blades, where each of said blades comprises a root arranged to pivot around a separate pivot pin at said hub in order to be in one of a first and second position, where the first position is an operative position, where the blades are pointing mainly in a radial direction, and where the second position is an inoperative position, where the blades are pointing mainly in an axial direction, where said hub comprises at least one cut out for said blades roots and further comprises a first set of holes for installing said pivot pins and a second set of holes for installing locking means for engagement with said pivot pins, wherein each of said locking means is a bolt or screw mounted in said second set of holes, wherein each of said pivot pins comprises means form of a through hole and a threaded hole for installation of said locking means, where each fastener is installed in a first pivot pin and further is engaging a second pivot pin whereby each pivot pin is connected with two fasteners and whereby the pivot pins and the fasteners are a closed structure that holds the propeller blades at the roots of the propeller blades.

2. A folding propeller according to claim 1, wherein said hub is manufactured from a plastic material.

3. A folding propeller according to claim 1, wherein said hub is manufactured from a metal alloy.

4. A folding propeller according to claim 1, wherein said hub comprises a link, where said link comprises means for interacting with at least two of said pivot pins and with at least two of said propeller blade roots.

5. A folding propeller according to claim 1, wherein said hub comprises at least one side link in which said first set of holes is located, where said at least one side link is embedded in the material of the hub, where said at least one side link comprises means for interacting with at least two of said pivot pins and with at least two of said propeller blade roots.

6. A folding propeller according to claim 1, wherein said folding propeller comprises at least two individual blades, each blade having a root comprising a gear engaging at least one further gear at at least one further blade root.

7. A folding propeller according to claim 1, wherein said hub comprises at least one compression cut out between said first set of holes for the pivot pins.

8. A folding propeller according to claim 1, wherein said folding propeller comprises shock absorber means, said shock absorber means being arranged at at least one blade root.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a two bladed folding propeller in an operative position;

(2) FIG. 2 shows a two bladed folding propeller in an inoperative position;

(3) FIG. 3 shows a two bladed folding propeller disassembled;

(4) FIG. 4 shows one embodiment of the propeller blades assembled without the hub;

(5) FIG. 5 shows another embodiment of the propeller blades assembled without the hub;

(6) FIG. 6 shows the shock absorber element at the propeller blades;

(7) FIG. 7 shows a hub and a cross sectional drawing of the hub and pivot pins for a three bladed folding propeller, and

(8) FIG. 8 shows a link for supporting the pivot pins and the hub for a three bladed folding propeller.

DETAILED DESCRIPTION OF THE INVENTION

(9) In the following text, the figures will be described one by one and the different parts and positions seen in the figures will be numbered with the same numbers in the different figures. Not all parts and positions indicated in a specific figure will necessarily be discussed together with that figure.

DETAILED DESCRIPTION OF THE INVENTION

(10) In FIG. 1 a two bladed folding propeller 1 is seen in an operative position, where the blades 3 are unfolded and extending in a more or less radial direction from the hub 2. At the end of the hub 2 an anode 4 is seen and on the side of the hub 2 the first set of holes 5 in the hub 2 is seen. In said first set of holes 5 the pivot pins 7 are arranged and secured.

(11) FIG. 2 show the same folding propeller 1 as seen in FIG. 1, but here, in an inoperative position, with the blades 3 folded and pointing in an axial direction.

(12) In FIG. 3 the same two bladed folding propellers 1, as also seen in the preceding figures, are seen, but here in a completely disassembled state, where all the various parts are seen. As can be seen the hub 2 comprises said first set of holes 5 and also a second set of holes 6 arranged perpendicular to the first set of holes 5 and in the same plane. In the second set of holes 6 the locking means 8, here in the shape of threaded bolts 8, will be installed. Between the two holes of the first set of holes 5 a so called compression cut out 9 is seen. The compression cut out 9 is actually an area that it is possible to compress and thus to adjust the distance between the two holes in the first set of holes 5. Said adjustment possibility is not very large but can, e.g., be between 0.1 to 3 millimeters or less or even more. In this embodiment the compression cut out 9 is actually a longhole arranged between the holes 5, but could also have comprised a weakened area due to reduced thickness, stiffness or by any other means.

(13) Perpendicular to the first set of holes 5, there is a cut out 10 for the propeller blade roots 11. When the propeller blades 3 are arranged in said cut out 10 the pivot pins 7 will be installed in the holes 5 and the bolts 8 will be installed in the second set of holes 6 in the hub 2. By tightening the bolts 8 the roots 11 will be pulled together and the gear at the roots will have the desired slack or clearance in order to work properly.

(14) The pivot pins 7 each have a through hole 12 and a threaded hole 13. A locking means/bolt 8 will be installed through said through hole 12 and into engagement with said threaded hole 13 in order to adjust the distance between the two pivot pins 7.

(15) Above the cut out 10 in the hub 2 a link 14 is seen, said link 14 has a set of holes 15 arranged for the pivot pins 7 to fit into. Further the propeller blade roots 11 also have a cut out 16 for the link to be positioned in. Then the pivot pin 7 can be installed in the holes 5 of the hub 2, and pushed into a corresponding hole 17 in the propeller blade root 11, into said link 14 and further through the other side of the propeller blade root 11 and into its final position in the hub 2 at the other side. After having installed both pivot pins 7, the locking means/bolts 8 will be installed and adjustment will take place.

(16) In this figure, the link 14 has a first purpose of supporting the pivot pins 7 and thus to relieve the hub 2 from some of the reactive forces from the blades 3 when the propeller 1 is operated. A second purpose is to act as a support for the anode 4 that is fastened to the link 14 by a bolt 18.

(17) At the propeller blade roots 11, a cut out 19 for a shock absorber 20 is seen. The shock absorber 20 will typically be made from a rubber compound and can be changed due to wear during dismantling of the folding propeller 1.

(18) In FIG. 4, only the blades 3, the pivot pins 7, the locking means 8 and the central link 14 are seen installed without the hub 2. This is, of course, a unrealistic situation, but for the purpose of understanding the position of the various parts it makes sense. The same goes for FIGS. 5 and 6.

(19) Here it can be seen that the two pivot pins 7 have identical design and that the locking means/bolts 8 are installed in a through hole 12 in one pivot pin 7 and into a threaded hole 13 in the other pivot pin 7. This design makes the locking means 8 and the pivot pins 7 together with the propeller blade roots take up practically all the mechanical loads, and thus the hub 2 can be manufactured from less rigid and strong material, e.g., a suitable polymer fiber or metal reinforced or not.

(20) FIG. 5 shows an alternative solution to what is seen in FIG. 3, as the central link 14 is replaced by two side links 21. Such side links 21 can be arranged as a spacer between the sidewall of the cut out 10 in the hub 2 and the propeller blade roots 11, but these side links can also be embedded in the hub 2, e.g., during molding of such a hub 2.

(21) FIG. 6 shows details about the shock absorber 20, where the contact area 22 on each of the propeller blade roots 11 is seen. The forces taken up by the shock absorber 20 is thus divided by two shock absorbers 20 and two contact areas 22.

(22) In FIG. 7, a cross sectional drawing of a hub 2 is seen, where the hub 2 is designed for three blades 3. To the right the hub 2 is seen from the side and to the left a cross section according to the line E-E is seen, directly through the pivot pins 7. Also here the pivot pins 7 have a through hole 12 and a threaded hole 13 for the locking means/bolts 8, and the system comprising the pivot pins 7 and the locking means 8 will take up the majority of the forces and reactions at the mentioned parts.

(23) Finally, FIG. 8 shows a triple link 23 for the solution seen in FIG. 6, where the triple link 23 will be installed with a pivot pin 7 in each of the holes 15 in order to support the pivot pins 7 and the hub 2. Centrally at the triple link 23 there is a hole 24 for a bolt 18 for fixating an anode 4.

(24) The invention is not limited to the embodiments described herein, and may be modified or adapted without departing from the scope of the present invention as described in the patent claims.