The present disclosure relates to a suction device, in particular to a suction device that may be attached to an underwater animal or vehicle. It further relates to a tracking device comprising the same.

Fish migration behaviour is complex and significant research is directed to better understanding it. A commonly used technique to track larger fish is to fit the fish with pop-up satellite tags. However, these tags inherently disrupt the fluid flow along the fish creating significant drag which can cause problems for the fish.

Consider, for example, sail fish, which are known to accelerate suddenly. The motor racing industry bases its business around optimizing the aerodynamics of its vehicles for sudden bursts of acceleration. Consider the impact one of these tags might have on a racing car’s performance and then draw parallels to the natural underwater world. By way of further example, spinner dolphins are thought to spin underwater and to breach and spin to throw off parasites. The attachment of a tracking tag might induce similar behavior in fish too, as they try to rid themselves of the tag. Inherently, the addition of these tags to the fish must disrupt their behaviour.

In a similar fashion to tracking fish through an undisruptive mechanism, there is also an advantage in using such a device to track underwater vehicles such as submarines. However, when covert operation is essential attaching something to the side of a submarine can, in itself, cause detection. Using some form of electromagnet to secure a tracking device to the side of a submarine would create significant detectable noise, thus rendering it detectable. Moreover, an electromagnet would require power, either a battery or some other way of generating power. A permanent magnet, whilst less detectable, may not detach easily.

The present invention arose as a result of work to develop an improved tracking device suitable for attachment to animals and vehicles.

According to the present invention in a first aspect, there is provided a suction device comprising a suction pad, the suction pad comprising a plurality of spaced substantially parallel flaps that have free ends for contacting an attachment surface in use.

By virtue of the provision of the flaps, there is uniquely provided a suction device that develops a suction force that is proportional to an external force applied to the suction pad. The suction force may vary during a sustained period of attachment in accordance with the external force. The suction device requires no power, it is passive.

The orientation of the flaps may be altered by the external force. To this end, the flaps are preferably flexible. They may be elastomeric. They may comprise silicone.

The suction pad preferably comprises an inner surface for facing the attachment surface in use, wherein the flaps depend from the inner surface.

The flaps may be integrally formed with a body of the suction pad. The suction pad may be unitarily formed. It may be moulded in a single piece.

The flaps are preferably arranged, at rest, at an oblique angle to a plane of a mouth of the suction pad. They preferably extend to the level of the mouth of the suction pad. The flaps are preferably arranged so that, in use, a pair of the flaps that are adjacent to one another together with a portion of an inner face of the suction pad, from which the flaps project, and the attachment surface close off a void that is substantially shaped as a parallelogram in section.

The suction pad is preferably elongate, extending along a longitudinal axis, and the free ends of the flaps preferably extend substantially perpendicular to the longitudinal axis.

The free end of one or more of the flaps may be provided with engagement members, which may comprise teeth or hooks.

According to the present invention in a further aspect, there is provided a tracking device comprising a suction device according to any of the above statements.

The tracking device preferably comprises an aerodynamically shaped body, which may have the form of a fish.

The tracking device preferably comprises one or more sensors and a power source. The power source may comprise a turbine.

The tracking device may comprise a secondary anchor, which may comprise a tether.

Exemplary embodiments will now be discussed with reference to the accompanying drawings, in which:

Figure 1 shows, schematically, a bottom view of a suction pad of the suction device according to a first embodiment of the invention; Figure 2 shows, schematically, a partial section view of the suction pad of Figure 1 taken through the line A-A in Figure 1 ;

Figures 3a and 3b show sequential schematic sectional drawings, illustrating the principles of the present invention, wherein Figure 3a shows a state of the suction pad prior to attachment and Figure 3b shows the suction pad following attachment to the attachment surface and the application of a force thereto;

Figure 4 shows a side view of an exemplary tracking device comprising a suction device in accordance with Figures 1 and 2;

Figure 5 shows a front view of the tracking device of Figure 4; and

Figure 6 shows a top view of the tracking device of Figure 4.

It must be noted that whilst the present disclosure focusses on the use of the suction device for attachment of a tracking device to an underwater animal or vehicle, its use need not be limited as such. It may find application in other environments/scenarios. Moreover, whilst the suction device is described in the context of a tracking device it may find wider application and its use is not to be limited.

With reference to Figures 1 , 2, 3a and 3b, there is shown, schematically, a suction pad 1 for a suction device. The suction pad comprises a plurality of spaced substantially parallel flaps 2 that have free ends for contacting an attachment surface 3 in use.

It should be noted that in arrangements with three or more flaps 2, the flaps 2 may be spaced equidistantly or the spacing may be variable between adjacent pairs of flaps 2.

The flaps 2 uniquely allow for the generation of a suction force, which can vary proportionally as a result of external forces applied to the suction pad 1 . In particular, in response to forces applied to the suction pad in a direction substantially parallel to the attachment surface or having a component substantially parallel to the attachment surface.

In the present arrangement, as is preferred, the flaps are flexible. By virtue of their flexibility, the orientation of the flaps 2 can be altered by the application of the external force to the suction pad 1 . This principle is best seen in Figures 3a and 3b.

In the present arrangement, as is further preferred the flaps 2 are arranged at an oblique angle to a plane of a mouth 4 of the suction pad 1 . They have this orientation when the suction pad 1 is at rest. Accordingly, when the suction pad is brought against an attachment surface for attachment, the flaps are arranged at an oblique angle with respect to the attachment surface, as seen in Figure 3a.

As illustrated schematically in Figure 3b, each pair of the flaps 2 that are adjacent to one another define, in section/profile, the sides of a parallelogram, wherein, in the depicted orientation an inner face 5 of the suction pad 1 , from which the flaps project, defines a top of the parallelogram and the attachment surface 3 defines a bottom of the parallelogram. Considered differently, these elements together close off a void that is substantially shaped as a parallelogram in section. With a plurality of spaced parallel flaps, there are preferably provided a series of these parallelograms.

With the application of a force to the suction pad and the free ends in contact with the attachment surface, the orientation of the flaps will change, as seen in Figure 3b (as compared to Figure 3a). In Figure 3b, the suction pad has been pushed by an external fluid flow so that the flaps 2 are closer to perpendicular with the attachment surface 3 and the parallelogram shape is closer to a rectangle in form. This has the effect of changing the pressure in the volume of fluid encapsulated by the suction pad 1 , which increases the suction pressure in direct proportion to the strength of the applied force. Clearly with a move back towards the position of Figure 3a, the suction force will be reduced.

Considering this principle in the context of an example, with the suction device to be attached to the body of a vehicle or animal underwater, when the suction device is close to contact with an attachment surface 3 in a slow current (for example 0.1 m/s) between the attachment surface and the body of the water - the ground effect will cause the suction pad to be drawn into contact with the surface, this is a very light pressure but it causes the device to very lightly anchor itself in position. Otherwise, if this very gentle approach is not possible, the suction device can be moved, or move itself, in such a way as to apply a small pressure between it and the surface, in a similar way to a very light pressure regular suction device. However, when the fluid flow increases, the fluid pressure over the device pushes it backwards slightly which alters the parallelogram shape into a more rectangular shape, thus changing the pressure in the volume encapsulated by the suction pad which increases the suction pressure in direct proportion to the strength of the current. To release the suction device, the suction pad is moved slightly forwards (i.e. against the current), either because the host surface has slowed down sufficiently in relation to the water current, or the device has applied forward propulsion. Thus the device makes it simple and efficient to disengage from the host, and raises or drops the suction pressure passively in direct proportion to the current.

Considering the exemplary embodiment of Figures 1 and 2 further, the suction pad has an elongate shape having a longitudinal axis; this is not essential but is preferred. In alternative arrangements, it could, for example, be round or square. As best seen in Figure 1 , when the suction pad is elongate, the free ends of the flaps 2 preferably extend substantially perpendicular to the longitudinal axis. With such an arrangement assuming the suction pad is oriented with the longitudinal axis substantially parallel to an external fluid flow, the flaps will extend substantially perpendicular to the external fluid flow and the resultant force applied to the suction pad.

The flaps 2 may be arranged in multiple rows or in a single row. As best seen in Figure 1 , there are two rows of flaps in the present arrangement. The flaps 2 are separated by a central rib 6, which extends in the direction of the longitudinal axis of the suction pad. In such a case, the rib 6 may be integrally formed with the flaps 2. In alternative arrangements a rib 6 may be provided that is formed separately or the rib could be omitted.

The flaps 2 may be integrally formed with the suction pad 1 . This is the case with the present exemplary arrangement, wherein the suction pad is unitarily formed from a flexible resilient material. This material may, for example, comprise any suitable elastomeric material. It may comprise silicone. The suction pad 1 in such an arrangement may be moulded in a single piece. In less preferred alternative arrangements, the ribs 2 could be formed separately to the remainder of the suction pad 1 .

The suction pad 1 comprises a body 7 and the flaps 2. Irrespective of shape, the body is preferably of conventional form, being cup/bowl like in form. The body 7 comprises the mouth 4, which is open for contacting the attachment surface 3. The open mouth 4 may be considered to lie in a single plane, which will substantially correspond to the plane of an attachment surface when that surface is planar. The body 7 comprises the inner surface 5 from which the flaps 2 depend. It is preferable that the flaps extend to the level of the mouth 4, as seen in Figure 2.

The flaps 2 whilst preferably entirely flexible could be otherwise formed. For example, they could in some instances comprise flexible ends with rigid central region extending therebetween. In such case, the flaps 2 could be attached to the body 5 of the suction pad 1 by a living hinge. The flaps 2 are straight in the present arrangement (in both plan view as seen in Figure 1 and in section/profile as seen in Figure 2), in alternative arrangements they may be curved or otherwise formed in either or both of plan and section.

In some instances, whilst not essential, it may be beneficial that the free end of one or more of the flaps 2 is provided with engagement members. For example, if the attachment surface is soft, slimy and/or slippery (in particular in the case of organic material such as a fish or sea mammal skin). The engagement members will aid in avoiding the entire device sliding backwards as the water speed and form drag increases. Such engagement members may, for example, comprise teeth or hooks.

With reference to Figures 4 to 6, there is shown an exemplary tracking device 10 comprising a suction device in accordance with the discussion above.

The tracking device 10 comprises a body 11 that is attached to a vehicle, animal or otherwise using the suction device. The form of the body 11 of the tracking device 10 need not be limited. It is preferably aerodynamically shaped to limit drag. Moreover, the suction device may be attached to numerous known tracking devices of varying forms. In the present arrangement, however, the body takes the form of a generic fish, featuring a body, one or more fins and a tail.

The tracking device comprises one or more sensors 12 and a power source. The tracking device is not to be limited to any particular form of sensor. The one or more sensors 12 may be housed entirely within the housing 11 of the tracking device 10 or sensors 12 may be provided internally and/or externally to the housing 11. For example, in the depicted arrangement bio electrical impedance analysis (BIA) sensors are provided externally to the housing 11 for the monitoring of an animal to which the tracking device is attached. A further sensor 12, such as a GPS tracker is provided within the housing. The sensors 12 will typically require a power source. The power source in the present arrangement comprises a turbine 13. Again, the tracking device 10 is not to be limited in this regard. Numerous alternative power sources (and combinations of power sources) will be readily appreciated by those skilled in the art, including batteries or otherwise.

In some instances, the tracking device 10 may further comprise a secondary anchor 14 in the form of a tether or otherwise. Clearly, the secondary anchor is not essential in many applications, wherein the suction device will provide the sole anchor means. In the present arrangement, however, a secondary anchor 14 in the form of a tether is shown. A secondary anchor 14 may be used, for example, when the tracking device 10 is attached to a marine animal. In such a case, one benefit of the combination of the suction device and the secondary anchor 14 is that the suction device reduces strain on the secondary anchor 14. Anchors used on conventional tags (that omit a suction device) are continually under variable pressure while the tagged animal is moving (as the anchors are the only thing holding the tag). The anchors alone are more likely to cause pain or discomfort, and increase healing time (or the time to become stabilized in the body). In contrast, with an arrangement according to the present invention that incorporates the suction device and a secondary anchor, the secondary anchor will not be under strain all the time and so will cause less irritation and make it easier for the body to be stabilized and heal.

The use of a suction device as described herein, clearly has significant benefits. It is passive, in that it requires no power to remain firmly attached. Suitable attachment force is generated though the host’s movement and it can be easily detached if required. Further, its attachment force is proportional to the force required (rather than too great or too little) to remain attached throughout the full range of movement of the host, which for a live host would minimize interference and stimulation from the device itself.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and/or to encompass equivalents.