GB2391845A

GB2391845A - Marine propulsion device with feathering blades

Info

Publication number: GB2391845A
Application number: GB0218768A
Authority: GB
Inventors: Philip Arthur Barnes
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-08-13
Filing date: 2002-08-13
Publication date: 2004-02-18
Also published as: GB0218768D0

Abstract

Propulsion apparatus (1) comprises a fixed member (8, 10) and a support (12) rotatable with respect to the fixed member (8, 10). At least two paddles (4, 6) are mounted on the rotatable support (12) for rotation with respect thereto and about generally parallel axes, with transmission means (50) drivably linking together the fixed member (8, 10) and the paddles (4, 6)at a gear ratio therebetween of 2:1.

Description

2391 845

Propulsion Apparatus Description

5 This invention relates to propulsion apparatus for propelling a vehicle through water and especially, but not exclusively, to manually drivable propulsion apparatus, for use in, for example, a pedal-powered vessel.

Accordingly, the present invention provides propulsion apparatus comprising: a fixed member; a support rotatable with respect to the fixed 15 member; at least two paddles mounted on the rotatable support for rotation with respect thereto and about generally parallel axles; and transmission means drivably linking together 20 the fixed member and the paddles, with a gear ratio therebetween of 2:l.

Preferably, the rotatable support is circular, in which case the fixed member may extend centrally 25 therethrough. In a preferred embodiment, the support is cylindrical, with a fixed elongate element, as the fixed member, extending coaxlally therethrough.

Also, only one pair of paddles may be used, in 30 which case, they are mounted on diametrically opposed sides of any circular or cylindrical support.

-2 In a preferred embodiment and when the rotatable support is cylindrical, each paddle may be mounted to the rotatable support by mounting rods.

The mounting rods may be secured to the wall of the s support, preferably by bearings in which they are rotatable.

In another preferred embodiment, each mounting rod may be fixed to the rotatable support and each 10 paddle may be mounted on the mounting rods by rotatable tubes encircling the mounting rods.

The transmission may be a system of sprockets and endless connecting chains which connect the 15 mounting rods or rotatable tubes to the fixed member. In a preferred embodiment, where the apparatus comprises two paddles, the fixed member may have two 20 sprockets each one of which preferably has N teeth.

In this preferred embodiment, each mounting rod or] rotatable tube may have one sprocket, preferably with 2N teeth, which is connected to one of the sprockets on the fixed member by, for example, an 25 endless chain.] The rotatable support is preferably connectable to a power source, such as a motor or manually-

operable power means, for example pedals.

The paddles may be of any suitable shape but in an embodiment to be described below, are tapered.

-3 Tapered blades help to shed weeds which might otherwise have become trapped in the apparatus and impeded motion.

5 In another preferred embodiment to be described below, the paddles may be rectangular in shape and may be arranged to rotate against at least one weed scraper, so that weeds do not get trapped on the blades. In order that the invention may be more fully understood, preferred embodiments of propulsion apparatus, in accordance therewith, will now be described by way of example only and with reference 15 to the accompanying drawings in which: Figure. l is a rear elevational view of an embodiment of propulsion apparatus in a vertical orientation; and Figure. 2 is a front elevational view of a second embodiment of propulsion apparatus in a horizontal orientation.

25 As shown in Figure l, a first vertical embodiment of propulsion apparatus, indicated generally at l, is shown mounted upon the left side of the hull 2 of a boat. Although only a left propulsion apparatus l is shown, it should be noted 30 that a second propulsion apparatus would be oppositely disposed on the right side of the hull 2 of the boat.

-4 The propulsion apparatus 1, as shown in Figure 1, comprises two polyhedral paddles 4, 6 rotatably mounted via respective mounting rods 8, 10 to a S rotatable drum 12, such that both the paddles 4, 6 themselves and the drum 12 along with the paddles 4, 6 can rotate in planetary fashion.

The apparatus 1 is mounted such that the top 10 and base walls 14, 16 of the rotatable drum 12 lie in planes generally parallel to the base (not shown) of the boat hull 2 to which the apparatus 1 is mounted. When mounted to the hull 2, the base wall 16 of the rotatable drum 12 is below water level 19.

A first, lowermost end 22 of each mounting rod 8, 10 is fixedly connected to the centre of each of the paddles 4, 6, with the other, uppermost end 24 of the mounting rods 8, 10 being mounted inside the 20 rotatable drum 12 to both the top and base walls 14, 16 thereof by bearings 26, 28 in which the mounting rods 8, 10 can rotate.

The paddles 4, 6 are mounted within the 25 rotatable drum 12 such that they are oppositely disposed with their faces 30 at right angles to one another and spaced at a distance which allows for their free rotation.

30 The propulsion apparatus 1, when mounted to the boat hull 2, is arranged such that the paddles 4, 6 are below the bottom wall 16 of the drum 12, with

-s- thelr narrower edges 32, 34 facing downwardly into the water when in use.

The paddles 4,6 are tapered towards their s narrow edges 32, 34 along the side walls 36 and the faces 30. Tapered blades help to shed weeds which might otherwise become trapped in the apparatus and impede motion 10 A handle 38, which in use is located inside the boat parallel to the top wall 14 of the rotatable drum 12, is associated with one end of a stationary rod 90 which extends at right angles to the handle 38 through the centre of an upright tubular housing l5 42 fixedly connected to the centre of top wall 14 of the rotatable drum 12. The lower end 44 of the stationary rod 40 extends through the top wall 14 of the drum 12 into the centre thereof.

20 The upright tubular housing 42 is rotatably mounted within a cylinder 46 which is fixed to the hull 2 of the boat and which acts to maintain the apparatus 1 secure and in its correct position within the hull 2. The cylinder 46 is positioned 25 above the rotatable drum 12 and is shaped and dimensioned such that the drum 12 is free to rotate within the hull 2 and the paddles 4, 6 are located at the correct height when the associated boat is in the water.

-6 As stated earlier, the hull 2 extends past the cylinder 46 and the rotatable drum 12 at the higher, left side 18 of the apparatus 1.

5 A weed scraper 48 is fixed at right angles to the higher, left side 18 of the hull 2 so that as the paddles 4, 6 rotate, any build up of weed or the like is removed and the paddles 4, 6 can rotate in an unobstructed manner.

The handle 38 acts as a control lever for a transmission system which connects the lower end 44 of the stationary rod 40 with the mounting rods 8, 10, inside the rotatable drum 12.

The transmission system consists of a pair of 10-teeth sprockets 50 fixedly connected to the lower end 44 of the stationary rod 40 and corresponding 20-teeth sprockets 52 fixedly connected to 20 respective mounting rods 8, 10 in the same planes as the 10-teeth sprockets 50. The 20-teeth sprocket 52 on each mounting rod 8, 10 is connected to the corresponding 10-teeth sprocket 50 on the stationary rod 40 by a chain 54 to form a transmission system 25 with a gear ratio of exactly 2:1.

To cause forward motion of the boat, the paddles 4, 6 are arranged such that in the start position the inner paddle 4 presents its blade edge 3U towards the front of the boat, with the outer paddle 6 being face 30 on, as shown in Figure 1.

To reverse this motion and cause the boat to move backwards, the paddles 4, 6 should be arranged such that, in the start position, the outer paddle 6 presents its edge towards the front of the boat, s with the inner paddle 4 being face 30 on. The paddle positions can be interchanged by turning the handle 38 through 180 degrees which, via the 2:1 gear ratio of the transmission inside the rotatable drum 12, causes the paddles 4, 6 to rotate through 90 degrees 10 into the opposite orientation. Alternatively, a reverse gear (not shown) could be used to control a spur gear 56 associated with the top of the upright tubular housing 42. This could be used to reverse the direction of rotation of the blades causing the 15 boat to move in the opposite direction.

Figure 1 shows the paddles set up in the forward start position.

20 To propel the boat in either direction, the rotatable drum 12 with the paddles 4, 6 and the paddles 4, 6 themselves are rotated. A motor (not shown) drives the spur gear 56 associated with the top of the upright tubular housing 42 causing it to 25 rotate in bearings 41, 43 which, in turn, causes the rotatable drum 12 to which it is fixedly connected, to rotate. The transmission provided by the sprockets 50, 52 causes the paddles 4, 6 to rotate about axes defined by the mounting rods 8, 10, as 30 the drum 12 rotates.

-8 When the drum 12 with the paddles 4, 6 have rotated through 180 degrees, the paddles 4, 6 themselves will have rotated through 90 degrees, such that they interchange orientation. This means s that, when travelling forward, the inner paddle 4 is always end on and when travelling backwards, the inner paddle 4 always presents its blade face 30 towards the front of the boat. Alternatively a reverse gear (not shown) can be used to control the lO spur gear 56 associated with the top of the upright tubular housing 42.

The movement of the paddles 4, 6 in this manner ensures that while one of the paddles 4, 6 is always 15 pushing against the water, to cause either forward or backwards motion, the other paddle 6, 4 moves through the water in an end-on orientation, therefore providing very little resistance and thereby increasing the efficiency of the apparatus Figure 2 shows a second, horizontal embodiment of propulsion apparatus which is indicated generally at 100 and which is mounted under a flat bottom boat 25 102 or between two hulls of a catamaran-type boat.

The apparatus 100 comprises two paddles 104, 106 rotatably mounted via rotatable tubes 109, 111 on mounting rods 108, 110. The mounting rods 108, 30 110 are part of a paddle enclosing structure which gives the apparatus 100 strength and rigidity. The paddle enclosing structure is formed at one end by a

rotatable drum 112 and at the other end by a disc 120. The two mounting rods 108, 110 are fixed at their respective ends to both the rotating drum 112 and the disc 120 to form the paddle enclosing 5 structure.

The rotatable tubes 109, 111 are mounted on the corresponding mounting rods 108, 110 and contained within the paddles 104, 106 such that the paddles 10 104, 106 are rotatable about the mounting rods 108, 110. The paddle enclosing structure is arranged to rotate as a unit about a stationary rod 130, at its IS rotating drum 112 end, and at its disc 120 end, about a bearing 121 which is attached to a strut 123 extending vertically from the flat bottom 102 of the boat. This arrangement means that, both the paddles 104, 106 themselves and the paddle enclosing 20 structure with the paddles 104, 106 can rotate in planetary fashion.

The apparatus 100 is mounted such that the outer and inner side walls 116, 114 of the rotatable 25 drum 112 lie in planes perpendicular to the flat bottom 102 of the boat to which the apparatus 100 is mounted. When mounted on a boat, both the rotatable drum 112 and the paddles 104, 106 are under water.

30 Each mounting rod 108, 110 extends through the centre of its corresponding rotatable tube 109, 111

- lo which in turn extends through the centre of its corresponding paddle 104, 106.

Each mounting rod 108, 110 is connected at a 5 first end 118 to the disc 120. The second end 124 of each mounting rod 108, 110 is mounted inside the rotatable drum 112 to the outer side wall 116.

The paddles 104, 106 are mounted by the 10 rotatable tubes 109, 111, such that they are oppositely disposed with their faces 128 at right angles to one another and spaced at a distance which allows for free rotation.

15 The apparatus 100, when mounted under a flat bottom boat 102, is arranged such that the rotational axes of the paddles 104, 106 are normal to the inner side wall 114 of the rotatable drum 112. A handle 131, which in use is located inside the boat, is associated with one end of the stationary rod 130 which extends at right angles to the handle 131 through the centre of a horizontal 25 tubular housing 132 fixedly connected to the centre of the outer side wall 116 of the rotatable drum 112. The stationary rod 130 also extends through the outer side wall 116 of the drum 112 into the centre thereof.

A circular weed scraper 134 is fixed around the circumference of the inner side wall 114 of the

il rotatable drum 112, so that, as the paddles 104, 106 rotate, any build up of weed or the like is removed and the paddles 104, 106 can rotate in an unobstructed manner.

s A second circular weed scraper 125 is fixed around the circumference of the disc 120, so that, as the paddles 104, 106 rotate, any build up of weed or the like is removed and the paddles 104, 106 can lo again rotate in an unobstructed manner.

The handle 131 acts as a control lever for a gear system which connects the end of the stationary rod 130 with the rotatable tubes 109, 111, inside IS the rotatable drum 112.

The gear system consists of a pair of 10-teeth sprockets 136 fixedly connected to one end of the stationary rod 130 and corresponding 20-teeth 20 sprockets 138 each fixedly connected to a rotating tube 109, 111 in the same plane as the corresponding 10-teeth sprocket 136. The 20-teeth sprocket 138 on each rotating tube 109, 111 is connected to the corresponding 10-teeth sprocket 136 on the 25 stationary rod 130 by an endless chain 140, to form a gear system with exactly a 2:1 ratio.

To cause forward motion of the boat, the paddles 104, 106 are arranged such that in the start 30 position, the lower paddle 104 presents its face 128 towards the front of the boat, with the other paddle 106 being edge on.

-12 To reverse this motion and cause the boat to move backwards, the paddles 104, 106 should be arranged such that in the start position the upper paddle 106 presents its face 128 towards the front 5 of the boat with the other paddle 104 being edge on.

The paddle positions are interchanged by turning the handle 131 through 180 degrees which, via the 2:1 gear ratio inside the rotatable drum 10 112, causes the paddles 104, 106 to rotate through 90 degrees into the opposite orientation.

Alternatively, a reverse gear (not shown) can be used to control a spur gear 142 associated with the end of the horizontal tubular housing 132.

To propel the boat in either direction, the rotatable drum 112 with the paddles 104, 106 and the paddles 104, 106 themselves are rotated. A motor (not shown) drives the spur gear 142 associated with 20 the horizontal tubular housing 132 causing it to rotate which, in turn, causes the paddle enclosing structure, to which it is fixedly connected, to rotate. The gear system rotates the paddles 104, 106 about respective axes defined by the mounting rods 25 108, llO as the paddle enclosing structure rotates.

When the drum 112 with the paddles 104, 106 is rotated through 180 degrees, the paddles 104, 106 themselves are rotated through 90 degrees, such that 30 they interchange orientation. This means that when travailing forwards, the lower paddle 104, 106

-13 always presents its face 128 towards the front of the boat.

r The rotational movement of the paddles 104, 106 5 in this manner ensures that while one of the paddles 109, 106 is always pushing against the water to cause either forward or backwards motion, the other paddle 106, 104 moves through the water in a side-on orientation, therefore providing very little 10 resistance and thereby increasing the efficiency of the propulsion apparatus 100.

Claims

-14 CLAIMS

l. Propulsion apparatus comprising: a fixed member; 5 a support rotatable with respect to the fixed member; at least two paddles mounted on the rotatable support for rotation with respect thereto and about generally parallel axles; and 10 transmission means drivably linking together the fixed member and the paddles, with a gear ratio therebetween of 2:l.
2. Apparatus according to claim l, wherein the 15 rotatable support is circular.
3. Apparatus according to claim l or 2, wherein the fixed member extends centrally through the rotatable support.
4. Apparatus according to any of claims l, 2 or 3, wherein the rotatable support is cylindrical.
5. Apparatus according to claim 4, wherein, when 2s the rotatable support is cylindrical, the fixed member comprises an elongate element.
6. Apparatus according to claim 4 or 5, wherein the fixed member extends coaxially through the 30 cylindrical rotatable support.

- l
7. Apparatus according to any preceding claim comprising a pair of paddles.
8. Apparatus according to claim 7, wherein the 5 paddles are mounted on diametrically opposed sides of any circular or cylindrical rotatable support.
9. Apparatus according to any preceding claim, wherein each paddle is mounted to the rotatable 10 support by a rod.
10. Apparatus according to claim 9, wherein when the rotatable support is cylindrical, each paddle mounting rod is secured to both axial end walls of Is the support.
11. Apparatus according to claim 9 or 10, wherein each mounting rod is secured by bearings in which it can rotate.
12. Apparatus according to claim 9 or 10, wherein each paddle is mounted to the rotatable support by a rotatable tube mounted on a respective rod.

25
13. Apparatus according to claim 12, wherein each mounting rod is fixed to the rotatable support.
14. Apparatus according to any preceding claim, wherein said transmission means comprises sprockets 30 and connecting chains.

-16
15. Apparatus according to claim 14, wherein the sprockets and chains connect any mounting rods or rotatable tubes to the fixed member.

s
16. Apparatus according to claim 14 or 15, wherein, with two paddles, the fixed member has two sprockets.
17. Apparatus according to claim 16, wherein each lo sprocket has N teeth.
18. Apparatus according to any of claims 14 to 17, wherein each mounting rod or rotatable tube has one sprocket.
19. Apparatus according to claim 18, wherein the sprockets on the mounting rods or rotatable tubes each have 2N teeth.
20 20. Apparatus according to any preceding claim including means for connection to a source of power.
21. Apparatus according to any preceding claim, wherein each paddle is tapered.
22. Propulsion apparatus substantially as hereinbefore described with reference to the accompanying drawings.

30
23. A vehicle incorporating a propulsion apparatus according to any preceding claim.