Automatically releasing watercraft attachment mechanism

Abstract

An attachment system 1, in the form of a leash, to attach a user to a watercraft which could be straight, coiled or elasticated and has at one end a magnetic coupler 2, 3, which provides an automatic release mechanism, as the magnetic attraction within the coupler provides a certain holding force so that the user remains attached to their watercraft during normal conditions and user actions. When a force greater than the holding force is applied between the user and the watercraft, the magnetic coupler separates leading to a smooth, fast release. A magnetic coupler adapted to be added to an existing watercraft attachment system is also disclosed.

Description

This invention relates to a device which attaches a user to a watercraft under normal operation but will automatically disengage if sufficiently high force is applied. Watercraft users, for example surfers, paddleboarders and foil boarders, often use a leash attaching themselves to their craft to aid re-mount in the event of falls or dismount. However, the use of conventional leashes can lead to entrapment and death if the leash gets stuck around an obstruction such as a pier, moored boat, tree, rock or coral for example. In moving water environments, ankle attachment leashes quickly become un-reachable as users are held underwater in flows exceeding 1.5 miles per hour. User operated quick release mechanisms, such as quick release belts, pins or shackles enable a user to release themselves from their leash, but not if they are incapacitated through unconsciousness, panic or illness. Some automatic release systems based on hook and loop material have been developed, but these have unpredictable release force and suffer from re-grab of the hook and loop in the release process, making it not a clean release. To overcome these problems, the present invention proposes a release mechanism which is incorporated in the leash, or an aftermarket additional component, and contains a magnet and associated metal component or two magnets with opposite poles which connect in-line with the leash, providing a point for the leash to separate when the force applied exceeds the force exerted by the magnet on the metal component or between the two magnets. The magnetic connection means is preferably provided using compact Neodymium disk magnets or a pot magnet and a ferrous disk, but any magnetic material and configuration could be used in its place such that it produces the same release effect. The attachment means may be adjustable or selectable so that the force necessary to separate the two components can be modified to suit the conditions, board, experience, weight and size of the user. The critical factors which set the ideal force necessary to separate the two components are set first by the forces experienced during normal watercraft use, enabling the user to remain attached to their watercraft under normal conditions and actions, and second, by the force that is acceptable to the user prior to automatic release. Normal use sets a lower limit to separation force which is as low as 20 N in flat water with slow speed falls at less than 3 mph for light weight users. This can rise to 100 N in the case of high speed, energetic water features such as waves or river rapids, and heavier weight users and can increase further when non-elasticated leashes are used. The ideal upper release force limit is set in most cases by the amount of buoyancy a user has when floating in the water, such that the magnetic connector will separate before the user is submerged. This is normally 40-150 N depending on the user, their clothing and if a personal flotation device is used. Therefore, there is an optimal typical release force range of 20-150 N which would suit the majority of users and watercraft in most conditions. For users operating at very high speed or in highly energetic features such as large waves or river rapids, a release force of up to 300 N might be appropriate, set by the point at which bruising or other body damage occurs around the user attachment point, or the breaking point of other components in the leash system, rather than the force at which they could be submerged. Higher release forces are not necessary as the magnetic release will not function prior to other equipment failure or serious injury to the user. Accordingly, a preferred range of release force is between approximately 20N and 300N. A more preferred range of release force is between approximately 30N and 150N, and a most preferred range of release force is between approximately 40 and 80N. Atypical means of measuring the release force is by using a load cell, such as a Pushton PSD-S1 High Precision Load Cell 100 kg, and analog to digital data acquisition system, such as a Picolog ADC-24, which has been calibrated using a 5 point calibration method. Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 shows a leash with a first embodiment of a magnetic in-line connector built in nearthe user connection point, which in Figure 1 is an ankle attachment. Figure 2 shows a close-up diagram of the first embodiment of the in-line connector in Figure 1 where the connection is made between two magnets with opposite poles facing each other. Figure 3 shows a close-up diagram of a second embodiment of the in-line connector in Figure 1 where the connection is made between a magnet and a ferrous metal piece. Figure 4 shows a third embodiment of the connector which allows for user adjustable release force. Figure 5 shows a leash with an in-line connector as shown in Figure 1 but used in conjunction with a waist or chest worn manual quick release belt. Figure 6 shows an implementation with two devices, which may be any combination of the first and second and third embodiments, at either end of the leash with different breaking forces. In Figure 1, a leash 1 which could be straight, coiled or elasticated, has at one end a pair of magnets 2,3 arranged with opposite poles facing each other such that they are attracted together on axis. This provides the automatic separation mechanism, as the magnets attract each other and hold together with a certain holding force, which can be controlled by selecting the strength of the magnet. In the case of Neodymium disk magnets this can be done simply by selecting the magnet diameter, field strength and / or the distance between them when the two sides of the connector are connected. When the magnetic holding force is exceeded, they separate and the attractive force between them decreases with increasing separation leading to a smooth release. One of the magnets is attached to the leash and the other is attached to an ankle cuff 4 which is attached to the user’s ankle. The other end of the leash consists of standard attachment points for watercraft, which may contain swivel connections 5 and cord 6. Figure 2 shows a first embodiment of the magnetic connector where two disk magnets 2, 3 are used, set up so that opposite poles face each other, and an attractive force is produced between them as they are brought close to each other. These magnets are housed in two connector bodies, 7 which have attachment points 8 on them for integration into a leash system. Figure 3 shows a second embodiment of the magnetic connector identical to Figure 2 except one side of the connector contains a permanent magnet 2, and the other contains a ferrous metal disk 9. Figure 4 shows a third embodiment of the magnetic connector where the force needed for release is adjustable by varying the separation of magnet 2 in its connector body 7, and magnet 3 in holder 10 by means of moving the position of magnet 3 compared to its holder 10. This could be achieved by using a threaded magnet and a simple screw adjustment 11, or by other means such as a series of spacer plates of different thickness giving known steps in release force the system provides. A ferrous disk could be used in place of either magnet 2 or 3 alternatively. Figure 5 shows a leash as in Figure 1, with magnets 2,3 located between the leash and a conventional quick release belt 12. Such a system provides a magnetic connector which will automatically disconnect in an emergency and also provides a conventional manually operated quick release mechanism which can be used when leaving or entering the water or if desired at any point by the user. Such a conventional manual quick release could also be embodied using releasable shackles or pins. An aftermarket version of the magnetic connector could be easily implemented in such a system between the ankle cuff of a standard leash and the attachment point of a standard quick release belt. Figure 6 shows a leash 1 which has two magnetic connectors, 13and 14, each of which can be any of the first, second or third embodiments outlined in Figures 2-4. This embodiment provides automatic release points both near the userand near the watercraft. In such an embodiment the magnetic force would be chosen such that the attachment point near the user will separate at lower force than that closest to the watercraft. This second release point 14 allows for automatic release in the case of the leash being wrapped around the user, stopping sufficient force to be applied to the primary release coupling, 13.

Claims

1. An attachment system adapted, in use, to permit attachment of a user to a watercraft, the attachment system comprising of a leash and a magnetic coupler, the magnetic coupler comprising a coupling force, wherein the magnetic coupler provides an automatic release mechanism, if a force greater than the magnetic coupling force is experienced between the user and the watercraft, to release the user from being attached to the watercraft.

2. An attachment system according to claim 1, in which the strength of the magnetic coupling is variable.

3. An attachment system according to claim 2, in which the variable magnetic coupling strength is achieved by means of controlling the spacing between the coupler plates using a mechanical screw-based adjustment system.

4. An attachment system according to claim 2, in which the strength of the variable magnetic coupling is achieved by means of controlling the spacing between the coupler plates using fixed thickness spacers which are attached to one or other side of the connector between.

5. An attachment system according to any preceding claim, in which the magnetic coupler consists of two magnets with opposing poles facing each other, such that they are attracted to each other.

6. An attachment system according to any preceding claim, in which the magnetic coupler consists of a magnetic component and a ferrous metallic component such that the ferrous metallic component is attracted to the magnet.

7. An attachment system according to any preceding claim, in which a second magnetic coupler is located in-line along the system length, one coupler with lower release force near the user and one with higher release force near the watercraft.

8. An attachment system accordingto any preceding claim which contains a straight, coiled or elasticated section to which one side of the magnetic coupler is attached and has an ankle cuff or other user attachment mechanism to which the second side of the magnetic coupler is attached.

9. An attachment system accordingto any preceding claim, which can be used in combination further comprising at least one manual quick release mechanism selected from cam buckle belts, hook and loop, shackle or pin based systems.

10. An attachment system accordingto any preceding claim, which has a magnetic coupling force in the range 20 to 300 N.

11. An attachment system according to any preceding claim, which contains an additional collar on one component of the magnetic coupler to ensure that only forces perpendicular to the coupler contact faces act on the coupler while forces parallel to the coupler contact faces do not.

12. An attachment system according to any preceding claim, which consists of disk shaped metallic or magnetic components, at least one of which is a Neodymium containing magnet.

13. An attachment system according to any preceding claim, which consists of a pot magnet and a disk shaped ferrous metallic disk.

14. An attachment system according to any of claims 1 to 13, where the watercraft is a paddleboard, also known as a SUP or stand up paddleboard.

15. An attachment system according to any of claims 1 to 13, where the watercraft is a surfboard.

16. An attachment system according to any of claims 1 to 13, where the watercraft is a hydrofoil board.

17. An attachment system accordingtoany of claims 1 to 13, where the watercraft is a a wingfoil.

18. An attachment system according to any of claims 1 to 13, where the watercraft is a windsurfing board.

19. An attachment system accordingtoany preceding claim, further comprising a watercraft attachment mechanism and a user attachment mechanism.

20. An attachment system according to claim 19, wherein the user attachment mechanism comprises of an ankle cuff, a leg cuff, an arm cuff, a wrist cuff, a waist belt of a chest belt.

21. An attachment system accordingtoany preceding claim, wherein the magnetic coupler is provided at some point within the length of the leash.

22. An attachment system according to any preceding claim 19, wherein the magnetic coupler is provided at one end of the leash and acts between the leash and one of the watercraft attachment mechanism and the user attachment mechanism.

23. A magnetic coupler adapted to be added to an existing watercraft attachment system, such that it separates the user from the watercraft when a force greater than the magnetic coupling force, which is in the range 20 to 300 N, is generated along the watercraft attachment system.

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