GB2608654A

GB2608654A - Wind powered self steering gear for sailing boats

Info

Publication number: GB2608654A
Application number: GB2109981.7A
Authority: GB
Inventors: Morritt Robin; Amadeus Solomon Morritt Zachary
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-07-09
Filing date: 2021-07-09
Publication date: 2023-01-11
Anticipated expiration: 2041-07-09
Also published as: GB202109981D0; GB2608654B

Abstract

A wind powered self-steering gear for a sailing boat comprising a wind vane and rudder with means to adjust the vessel's heading while under way using a handwheel connected to a reduction gear train and a differential gear train. The steering gear compromises a wind vane (1, figure 10) and shaft that is internally attached to bearings contained within a hollow rudder. The connection between the vane and rudder comprises a differential bevel gear (10, figure 16) consisting of multiple pinions mounted on a pinion gear carrier (11, figure 10) and having a ratio of 1:0:-1. The hand wheel connection comprises a cycloidal gear train that acts on differential gear train pinion carrier and the rudder

Description

Wind powered self steering gear for sailing boats Introduction and Summary of Invention This invention relates to a type of wind powered self steering gear known in the art as vertical axis direct acting. It is the object of this design to provide a convenient means of course adjustment and a compact construction for this type of device.

Background

Sailing boats require continual course correction while under way. This task is traditionally performed by a helmsman, but it is sometimes better to use a wind powered device, such as for shorthanded, single handed or unmanned craft, night time sailing and extended passagemaking.

In the 1870s, yacht designer Nathanael Herreshoff fitted a wind vane to a model yacht. Such a device was independently reinvented in the 1930s by Jacob Mikkelsen Iversen, Patent Number GB392451, with the addition of an engagement disc and finger (claim 2 and numbers 3 and 4 in the drawings). The device was scaled up in the 1950s by yacht designer Mike Henderson for the nineteen foot waterline length yacht Mick the Miller, in which the wind vane acted on a second, auxiliary rudder fitted to the boat in addition to the main rudder. In the 1960s, John Adam designed a functionally equivalent device in which the wind vane and auxiliary rudder were combined into a single assembly for attachment to the boat transom. After a transatlantic crossing in his seventeen foot boat Eve, John Adams designed the "Windpilot Atlantik" which remained commercially available until the 1980s.

The main innovations in wind powered self steering gear were explored by boat owners and enthusiasts from the 1930s to the 1960s. Information was freely shared and reported in magazine articles and books. The archive of the Amateur Yacht Research Society formed in 1955 is a useful source of information for that period. "Vertical axis" windvanes were superseded by "horizontal axis" windvanes which develop more power from the wind at low angles of attack. "Direct acting" self steering gear were also superseded by "indirect acting", or "servo" devices. When reliable horizontal axis and servo systems became commercially available, the vertical axis direct acting device became obsolete.

The prior state of the art for the vertical axis, direct acting class of wind operated self steering gear is therefore John Adam's Windpilot Atlantik design circa 1967.

The present invention is a development based on the prior art, for manufacture using contemporary materials and so-called Rapid Prototyping technologies, CAD/CAM/CNC/FDM.

The invention will now be described with reference to the accompanying drawings in which: Figures 1 and 2 illustrate the layout and proportions of a typical installation. Figures 3 and 4 are embodiments of the invention.

Figures 5 to 8 illustrate relevant features of the prior state of the art.

Figures 9 to 13 illustrate how the present invention compares to the prior state of the art. Figures 14 to 17 are construction drawings, excluding the Course Adjustment Means. Figures 18 to 26 are detail construction drawings of the Course Adjustment Means.

Description

With reference to Drawings page 1: In Figure 1, Self Steering Gear 1 is attached to Boat Hull 2. When the boat is moving through the water and the self steering gear is operating, Tiller 3, connected to Rudder 4, is normally lashed amidships. In this condition, the self steering gear works as described by Jacob Iversen in GB392451. Dashed line 5 represents the vessel's waterline at rest and Figure 2 is the top view of Figure 1.

Figure 3 and Figure 4 are embodiments of the invention. Figure 3 includes means to disconnect the wind vane, remove the windvane, lock the rudder, remove the rudder and a compression strut. Hereinafter, this description and drawings will explain the invention in terms of Figure 4 which omits those details.

Drawings page 2: The purpose of Figures 5 to 13 is to illustrate the differences between the prior state of the art and the present invention. Spur Gears 6 and 7 of the old design are substituted with Crown Gears 10 and 12, together with Pinion Gear Assembly 11 in the new design. The Course Adjustment Means 8 of the old design is a clamp that allows Spur Gear 7 to be angularly repositioned on its shaft. The same result is achieved in the new design by angularly repositioning Pinion Gear Assembly 11 about the vertical axis, using a cycloidal gear train details not shown on this page. Bracket 9 of the old design, and Bearing Housings 13, 14 of the new design, attach to the transom of the boat. Figures 8 and 13 illustrate the double axis style of the old design and the single axis style of the present invention.

Drawings page 3: Figures 14, 15, 16 and 17 and insets are section views showing the construction and assembly of the device. Figure 15 and insets are at 6 x scale.

In Wind Vane Assembly, Figure 14, Wind Vane 15 is fixedly attached to Wind Vane Shaft 16 and Crown Bevel Gear 12 and Guide Pin 19 and the inner race of Bearing 17; Bearing Sleeve 18 is fixedly attached to the outer race of Bearing 17 so that Bearing Sleeve 18 is rotatably attached to Wind Vane Shaft 16. In Pinion Gear Assembly 11, Figure 15, Pinion Gear Shafts 20 x 4 are fixedly attached to Carrier 21, shown in simplified form on this page 3. Pinion Gears 22 x 4 are not attached and can freely rotate and slide on Pinion Gear Shafts 20 x 4. In Rudder Assembly, Figure 16, hollow Rudder Shaft 23 is fixedly attached to Crown Bevel Gear 10, the inner races of bearings in Bearing Housings 13 and 14, internal Guide Pin Bush 24 and Rudder 25.

In Figure 17, Self Steering Gear is assembled by passing Wind Vane Shaft 16 down through Pinion Gear Assembly 11 and down through Rudder Shaft 23 until simultaneously Guide Pin 19 engages in Guide Pin Bush 24, and Bearing Sleeve 18 seats on Rudder Shaft 23. Bearing Sleeve 18 is then fixedly attached to Rudder Shaft 23, and the complete Wind Vane Assembly is as shown, excluding the Course Adjustment Means. Pinion Gear Assembly 11 is an unsupported captive component due to the bevel geometry and meshed gears. When Bearing Housings 13 and 14 are attached to the transom of a boat, the Wind Vane Assembly, Pinion Gear Assembly and Rudder Assembly are all rotatably attached to the boat and mutually constrained by the gear ratio 1:0:-1.

Drawings page 4: The Course Adjustment Means uses a non-backwardly drivable modified cycloidal reduction gear train to transfer the rotation of a handwheel to the pinion gear carriage of the differential gear such that the pinion gear carriage can be angularly displaced about the vertical axis and remain fixed in that position when the handwheel is released. When the angular position of the pinion gear carriage is fixed, the self steering gear indefinitely maintains a constant course relative to the wind direction. Since the pinion gear carriage can be rotated 360 degrees, the self steering gear can be set using the handwheel for any desired heading relative to the wind.

Figure 18 is the top view and Figure 19 is the iso view of camshaft 26 incorporating three cams. The cams are circles of increasing size, offset by the same eccentricity and angularly displaced by 120 degrees. Figure 20 shows one of three similar discs. Figure 21 shows the cam and disks, Assembly 27.

Figure 22 shows Enclosure 28 which incorporates Annular Gear, and cam and disks Assembly 27. Camshaft 26 is supported by enclosure not shown, as well as by the gear disks. The gearing is designed for manual operation and is constructed of lightweight materials, and has a flattened tooth form to limit flexing of Enclosure 28 and Annular Gear in order to prevent jamming of the gear train.

Figure 23 shows iso view of Pinion Gear Carrier with upwardly pointing pins x 8. Figure 24 shows Pinion Gear Carrier Assembly with Pinion Gear Shafts x 4 and Pinion Gears x 4 in section iso view.

Figure 25 shows the complete Course Adjustment Means. Handwheel 29 is fixedly attached to Camshaft 26 which is rotatably fixed to enclosure not shown. When Handwheel 29 is turned 360 degrees, the set of Disks 27 roll around the Annular Gear approximately 9 degrees. Pinion Gear Assembly 11 is a captive component of Crown Gears not shown, such that the upwardly pointing pins project through holes in Gear Disk Assembly 27. The angular position of Pinion Gear Assembly 11 turns approximately 9 degrees for each revolution of Handwheel 29. The effect of this is to change the angular position of the wind vane, relative to the rudder, by 18 degrees; and, under way, for the boat to alter its heading by 18 degrees relative to the wind direction for one full turn of Handwheel 29.

Figure 26 is a side section view of the complete mechanism. Hollow Camshaft 26 is rotatably attached to Number 28 which is part of the Enclosure Assembly. Wind Vane Shaft 16 passes through larger diameter centre hole of hollow Camshaft 26 without making contact.

Claims

Claims 1. A wind powered self steering gear for sailing boats comprising attachment means for attaching the device to a boat, a wind vane and shaft internally rotatably attached to bearings contained within hollow rudder shaft, a differential bevel gear including multiple pinions mounted on a pinion gear carrier connecting wind vane shaft to rudder shaft in the ratio 1:0:-1, a handwheel operated course adjustment means of a cycloidal gear train type acting on differential gear train pinion carrier, and a rudder.