EP0146240A1

EP0146240A1 - Steerable sailboard or the like

Info

Publication number: EP0146240A1
Application number: EP84307284A
Authority: EP
Inventors: David Severs Lambert
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-10-27
Filing date: 1984-10-23
Publication date: 1985-06-26
Also published as: GB8328763D0

Abstract

A wind-powered vehicle, such as a sailboard or a similar vehicle for use on land, snow or ice, having a generally flat body, a mast secured to the body by a universal joint and a sail carried by the mast, is provided with a foot-operated steering means. For example, the steering means may be a rotatably mounted fin (10), skeg (24,37), wheel, castor, skate, ski, runner or skid and may be operated by a footplate (4, 12, 30) or foot lever. The footplate or foot lever may be linked to the steering means by, for example, a direct connection (7), a cable (15, 16) or a mechanical linkage (40).

Description

The present invention is concerned with that class of wind-powered vehicles typified by the sailboard. Vehicles of this type, which variously may be suitable for use on water, land, snow or ice, characteristically have a sail supported by a mast which is secured to the body of the vehicle by a universal joint.
The steering of such vehicles is normally achieved by varying the position of the mast relative to the body of the vehicle, such movement of the mast being made directly by the operator, who conventionally adopts a range of standing positions in order to counter-balance the power of the wind against the sail. It is an object of the present invention to provide a vehicle of this type having greater flexibility of control than has hitherto been available.
The wind-powered vehicle of the present invention is characterised by having foot-operated steering means.
Thus my invention is e wind-powered vehicle of the type having a mast, secured to the body of the vehicle by a universal joint, a sail carried by that mast, and a foot-operated steering means.
As indicated above, vehicles of the sailboard type have been used not only on water, for which purpose they were originally developed, but also on land, snow and ice. My invention is applicable to all such vehicles of the sailboard type. Thus land-based vehicles of this type, which are provided with wheels or castors, may according to my invention be fitted with one or more foot-operated steerable wheels or castors. The snow-and ice-based versions of my invention have skates, skis, runners or skids and are fitted with one or more foot-operated skates or skids. Usually the land-based and ice-based sailboards are mounted at three points on wheels, skates or the like, two of which are disposed towards the rear of the vehicle and the third towards the front. It is then convenient for the single forward wheel, skate or the like to be foot-steerable. Alternatively, a single rear skid, or one or both of a pair of rear wheels, skates or the like, may be foot-steerable. In the case of a snow-based vehicle, which may be mounted upon a pair of ski-like runners, either or both of the runners may be foot-steerable.
My invention is particularly applicable to sailboards of the type which are designed for use on water. For convenience, it will hereinafter be described primarily in the context of such sailboards. However, it should be understood that many or all of the features hereinafter described are readily applicable or adaptable to land-based, snow-based and ice-based boards.
In the case of a sailboard for water, the steering means may take the form of one or more fins, specifically provided for steering purposes and mounted so as to pivot to a greater or lesser extent about a generally vertical axis. In another form, the steering means may extend aft of the board in the manner of a rudder. Alternatively, the steering means may be an adaptation of the so-called skeg or skegs which are usually provided on a sailboard. That is, the steering means may be of the same size and located in the same position on the board as a conventional skeg and located in the same position on the board as a conventional skeg but may be steerable in accordance with my invention. With a dual-function skeg of this type in particular, it is advantageous to provide means for locking the skeg in the straight fore-and-aft ("central") position for conventional sailboarding. Alternatively, or in addition, the skeg may be biassed towards said central position, either to assist ready centralisation by foot operation or sufficiently to align itself in the central position automatically when foot control is removed.
According to one optional but preferred feature of my invention, the steering means, for example a skeg, may be locked or lockable in the central position such that water or other pressure cannot divert the steering means from that position. In a preferred embodiment of my invention, described hereinafter, the locking may be an automatic feature of the design of the steering mechanism. Alternatively, a pin, latch or lever may be provided to permit manual locking when it is desired to immobilise the steering means.
According to another preferred feature of my invention, the pressure necessary to turn the steering means may progressively increase the further the latter is turned from the central position. For example the turning moment may progressively decrease or the resistance, for example spring resistance, may progressively increase.
The operation of the steering mechanism by means of the user's foot may be achieved in various ways. Thus, for instance, the pivot upon which the steering control, e.g. the skeg, is mounted may extend through the board and carry, on its upper end, a lever or footplate which itself is turnable by the foot so as to give direct foot-control of the steering. A footstrap may be provided to assist the gripping of this control member. In another form of my invention, the steering mechanism may be operable indirectly via an appropriate mechanical or cable linkage. Thus a rotatably-mounted footplate may be linked by levers or cables to a rotatably-mounted skeg or fin. As one alternative, the foot control may take the form of a rocking lever or plate, such that foot pressureon one side of the latter causes the skeg or fin to swing in one direction and foot pressure on the other side causes swing of the skeg or fin in the opposite angular direction.
As a less-preferred alternative, the link between the foot control and the skeg or fin may be by means of a gear train or worm drive.
Advantageously, a small freedom of movement of the foot control is provided in order that involuntary turning of the steering means does not occur.
The position of the user on the sailboard will change many times dependent not only upon the particular direction of sailing in relation to the wind but also upon the sailing mode and prevailing sea conditions. Thus it is advantageous for the foot control to be operable from more than one position on the sailboard. This may be achieved either by providing a combination of direct control through the sailboard with an indirect control via levers or cables, or by providing a plurality of such indirect controls. Thus two or more footstraps may be provided, linked directly together so that the control action is readily achieved in the same manner at two or more points of the board.
It is, of course, also possible to provide direct individual control of two or more separate skegs mounted at different points of the board but this is not a preferred form of my invention.
Because my invention possesses many of the features of a conventional sailboard, it is possible to make my sailboard by modifying an already existing board. Thus the board may be pierced with a pivot at an appropriate point or the link between foot control and pivoted skeg or fin may be made by means of a cable passing through the daggerboard casing or through a specially-cut extension of the latter.
The materials of contruction of the sailboard according to my invention need not differ from those of a conventional sailboard. Thus the shell of the board may be of epoxy resin or of cross-linked polyethylene and the filling may be of a rigid polyurethene foam. Those components which are characteristic of my invention may be made in a range of synthetic plastics materials, including nylon and polypropylene, depending upon the required life and bouyancy, and where appropriate of stainless steel, brass or anodised aluminium.
Those skilled in the art of sailboarding will be aware of the conflict in demands being made upon boards as specialist sailboards have developed. On the one hand, as the user develops an interest and skill in guiding the board by varying the position and pressure of his feet upon the board, he demands a sailboard of narrower aft end with hard "water-release" rails. These flat- bottomed boards will only steer in such a way at planing speeds. On the other hand, the less experienced boardsailor or the user who wishes to practice wave-jumping requires a sailboard with a wider stern. My invention, by providing an additional steering control, introduces a greater degree of freedom into sailboard design and helps to bridge the gap between the above extremes.
My invention will now be further described with reference to the accompanying drawings, in which:-

Fig. 1 illustrates in cut-away perspective view a direct foot control arrangement for one form of sailboard according to my invention;
Fig. 2 is a cross-sectional view of the sailboard of Fig. 1;
Fig. 3 is a cross-section corresponding to Fig. 2 with the foot control in a different rotational position;
Figs. 4A and 4B together are an exploded perspective view of another form of steering mechanism for a sailboard according to my invenflon;
Fig. 5 is an exploded perspective view of yet another form of steering mechanism for a sailboard according to my invention; and
Figs. 6A, 6B and 6C illustrate different positions in the operation of the mechanism of Fig. 5.

Referring firstly to Fig. 1, a sailboard 1 comprises a core 2 of rigid polyurethane foam sealed within a shell 3 of epoxy resin. A circular footplate 4 with footstrap 5 is secured by means of a hexagonal nut 6 upon the upper end of an elastic connecting pivot 7 which is located in a cylindrical channel 8 extending through the sailboard 1. To the lower end of the pivot 7 is secured a fin plate 9 carrying a pair of splayed fins 10.
The footplate 4 has a cam-shaped circumferential profile which, when the fins are aligned with the length of the sailboard 1, matches the profile of the bed 11 upon which the footplate nests. The footplate 4 is continuously urged into contact with the bed 11 by tension in the connecting pivot 7, which tension may be modified by adjustment of the nut 6. The tendency, therefore, is for the footplate to turn, in the absence of other factors, to the position shown in Fig. 2 in which the fins 10 are in line with the sailboard 1. In this position, the fins have a generally stabilising influence on sailboard performance, tending to hold the board against side-slip during turns.
As more clearly seen in Fig. 3, turning of the footplate 4 against the resistance of the tension in the connecting pivot 7 moves the fins 10 into a selected position in which the fins are to a greater or lesser extent inclined to the length of the sailboard 1 and therefore encourage turning of the board in the chosen direction.
The mechanism illustrated in Figs. 4A and 4B is of a type which can be applied to an existing sailboard without providing the cylindrical channel through the board -hickness necessary for the mechanism shown in Fig. 1. Fig 4A shows the part of the mechanism which is mounted on the upper side of the board, as viewed from above; Fig. 4B shows that part which is mounted on the under side of the board, as viewed from below.
In Figs. 4A and 4B, a circular footplate 12 with footstrap 13 is mounted upon the sailboard (which is not shown) on a central pivot 14. The footplate 12 is linked by cables 15 and 16, which pass through the dagger casing 17, to a stainless steel actuator 18, pivotally mounted on the under side of the board. The methods of mounting of the footplate and of the actuator use existing board features and therefore avoid the need for breaching of the board shell. Thus the pivot 14 of the footplate 12 is secured by means of an expanding fastener in one of the recesses already provided in the board for securing a fixed footstrap. The actuator 18 uses the skeg box 19 in which, in the original sailboard, a skeg has been removably mounted. The skeg box 19, having an elongated slot 20 in which the skeg would normally be mounted, is modified to receive expandable fasteners 21, by means of which a stainless steel plate 22 is secured to the board, and a square-headed nylon bolt 23 which projects through the plate 22. The actuator 18 and the skeg 24, trimmed of its mounting by which it would otherwise have been rigidly secured to the board, are secured to the end of the bolt 23 by means of a nylon locking nut 25.
The bolt 23 is urged by a spring, not shown, to return the actuator 18 to that position in which the skeg 24 is aligned with the length of the sailboard, in which position the skeg performs its normal stabilising function. However, when the footplate 12 is turned so as to exert a pull on one of the cables 15 and 16 and so turn the actuator 18 in the same rotational direction as the footplate, the skeg 24 is pivoted, against the spring-return action, to divert the sailboard in the desired direction.
Referring now to the embodiment of my invention illustrated in Fig. 5, a footplate 30 is pivotally mounted by means of a pivot pin 31 upon a base plate 32 secured to a sailboard 33. The footplate 30 carries two footstraps 34 to enable the sailboard user to turn the footplate 30 by appropriate foot pressure. Fixed footstraps (not shown) are provided on the sailboard in the conventional manner and the user-will normally ride the board using one fixed footstrap and one of the footstraps 34. Mounted within the sailboard 33 and rearward of the base plate 32 is a skeg hub 35, fixed against rotation by means of screw holes 36 and carrying a skeg 37 pivoted thereon by a pivot pin 38. The mounting of the skeg 37 on the sailboard is cushioned by means of a shock-absorbing spring 39, which reduces the effect on the sailboard of any impact on the skeg.
The footplate 30 and the skeg 37 are linked by a linkage 40, which is essentially rigid but has a degree of resilient lateral flexibility. At its forward end, the linkage 40 has an upstanding integral pin 41 which engages a socket 42 in the footplate 30. At its rearward end, the linkage 40is cut away at 43 to engage a pair of actuator pins 44A and 44B, by means of which the skeg is turned.
A sliding fit upon the linkage 40 are a pair of retaining collars 45A and 45B, urged apart by a compression spring 46. The pins 44A and 44B are carried by the collars 45A and 45B respectively, being secured thereto by threaded portions at the upper ends of the pins. These threaded portions extend through the walls of the respective retaining collars to as to protrude into the recess 43 and be engaged by the shoulders 43a and 43b respectively as the linkage is moved in a linear direction. The actuator pins 44A and 44B are located in a slot 47 in the skeg hub 35 and are thereby restricted to movement along a linear path.
In the upper end of the skeg 37 are two slots 48 and 49, whose shape is more clearly seen in Figs. 6A to 6C. The actuator pins 44A and 44B are able to engage the slots 48 and 49 respectively and bring about turning of the skeg. As is illustrated in Figs 6A to 6C, the further the skeg turns, the less becomes the radius of moment of the actuator pin upon the respective slot and therefore the greater becomes the foot pressure required to turn the skeg.
At rest, the pins 44A and 44B abut shoulders 50 and 51 respectively, adjacent to the respective slots 48 and 49, and thereby lock the skeg in its position in which it is aligned will the length of the sailboard. When the pins 44A and 44B are together or individually at rest, they nest in respective hollows 52 and 53 in the inner wall of the skeg hub 35.
Associated with each of Figs. 6A to 6C is an illustration of the condition of the compression spring 46 in each case.
As is readily seen, when the footplate 30 is rotated in an anti-clockwise direction as illustrated in Fig. 6^B, the linkage 40 is urged towards the right and the actuator pin 44A engages the slot 48 and turns the skeg 37 in the same direction. The pin 44B remains in its hollow 53. Similarly, clockwise rotation of the footplate 30, as shown in Fig. 6C, causes the pin 44B to enter the slot 49 and turn the skeg 37 also in a clockwise direction.

Claims

1. A wind-powered vehicle comprising a generally flat body, a mast secured to the body by a universal joint and a sail carried by the mast, characterised by having a foot-operated steering means.

2. A wind-powered vehicle according to claim 1, having wheels, castors, skates, skis, runners or skids, characterised in that at least one wheel, castor, skate, ski, runner or skid is foot-steerable.

3. A wind-powered vehicle according to claim 1, being a sailboard, characterised bytaving a foot-steerable fin or skeg.

4. A wind-powered vehicle according to claim 1, being a sailboard, characterised by having a foot-steerable rudder.

5. A wind-powered vehicle according to any of the preceding claims, characterised in that the foot-operated steering means is biassed towards a central position in which it is generally aligned with the vehicle.

6. A wind-powered vehicle according to claim 5, characterised in that the steering means is designed to require progresssively greater pressure to turn it the further it is turned from the central position.

7. A wind-powered vehicle according to any of the preceding claims, characterised in that it is automatically locked against involuntary turning, or is provided with means for locking it, when in the central position.

8. A wind-powered vehicle according to any of the preceding claims, characterised in that it is operated by a foot lever or rotary footplate.

9. A wind-powered vehicle according to claim 8, characterised by a rotary footplate directly connected to a rotatably-mounted steering means.

10. A wind-powered vehicle according to claim 8, characterised in that said foot lever or footplate is linked by a mechanical or cable linkage or by a gear train or worm drive to a rotatably-mounted steering means.

11. A wind-powered vehicle according to any of the preceding claims, characterised by a small freedom of movement between the foot control and the steering means.

12. A wind-powered vehicle comprising a sailboard, a mast secured to said sailboard by a universal joint and a sail carried by the mast, characterised in that the sailboard has a steerable fin or skeg mounted for rotation on the underside of the board, a footplate mounted for rotation on the upper side of the board, and a direct mechanical linkage between the fin or skeg and the footplate, so that rotation of the footplate causes rotation of the fin or skeg.