GB2055587A - Enhancing propulsion when swimming - Google Patents

Abstract

A leg attachment 5 comprises a concave pocket 3 which is expansible to entrain water on a kick stroke and enhances thrust against the water. The attachment is secured to a boot and may surround it. The pocket is normally held closed by an elastic strip 7. Weights 30 may be attached to the boots. The attachment is stated to be wearable. <IMAGE>

Description

SPECIFICATION Device for enhancing propulsion when swimming The invention relates to a device for enhancing propulsion when swimming, and particularly relates to subaquatic swimming.

Devices for enhancing propulsion that have been proposed are generally in the form of simulated webs or "flippers" which are worn on the feet. These prior art "flippers" have the disadvantage that they are very difficult to walk in, both on land and also underwater where the user may be a diver carrying out work on the bed of a stretch of water.

It is an object of the invention to seek to mitigate this disadvantage of the prior art.

According to the invention there is provided a device for enhancing propulsion when swimming, which is adapted for wearing on a limb of a user and comprises concave pocket means for entraining water on a propelling stroke of the user so as to enhance propulsion through the water.

The advantage which may be obtained owing to the invention is that the device can be worn on the ar. fm or leg of the user without encumberance while on land and yet enables the user to swim more efficiently because, when worn on the leg, fewer kicks are required to go the same distance as when not using the device or, alternatively, the user can go faster and further with same energy consumption as without the device. In other words, when oxygen is being used it is used more efficiently and can be made to service a longer period underwater.

The pocket means may have means for collapsing the pocket on a return stroke. The construction provides a stream-lined effect which reduces drag.

The collapsing means may be a biassing device, preferably an elastic strip, joining opposite sides of the pocket. This construction is relatively simple and yet achieves the desired collapsing effect.

In order to assist the expansion of the pocket means on a propulsion stroke, there may be gusset means which extends longitudinallyofthe device.

The device may preferably comprise releasable fastening means whereby the device can be relatively simply mounted on, and removed from, a limb ofa user.

Embodiments ofthe invention are hereinafter described, by way of example, with reference to the accompanying drawings.

Figure 1 shows a first embodiment and the way it is attached to a boot.

Figure 2 shows a side elevation of the device of Figure 1; Figure 3 shows a partial longitudinal sectional view of the device of Figures 1 and 2; Figure 4 shows a perspective view of a second embodiment of device; Figure 5 shows a partial longitudinal sectional view of the device of Figure 4; Figures 6 and 7 show the device of Figures 4 and 5 in use; and Figure 8 shows a view of an auxiliary weight for a boot.

Referring to the drawings Figures 1 to 3, there is shown a device 1 for enhancing propulsion when swimming underwater comprising a rubber body 2 which includes a concave downwardly, as viewed, pocket 3 on the outward (to the right as viewed in Figure 1) side of the device 1.

The concave pocket 3 is formed between inner 4 and outer 5 layers of the device 1. The inner layer 4 extends round part of a limb of a user. The outer layer 5 has a longitudinal gusset 6 which helps the pocket 3 to expand. The inner 4 and outer 5 layers are joined by biassing means 7 in the form of an elastic strip which normally acts to draw the outer layer 5 to the inner layer 4 to close the pocket 3.

The device 1 has fastening means in the form of eyelets 8 through which turn buttons 9 of a diving boot 10 can be passed to secure the device 1 to the boot 10.

In use, the device 1 is mounted on the diving boot 10 by passing the buttons 9through the eyelets 8 so that the device is attached to the limb of a user at the calf. There is a device 1 on each leg. On a propulsion stroke, the open mouth of the pocket 3 entrains water and as the leg is kicked the pocket 3 opens overcoming the biassing means 7 and presenting a large surface area to the water so enhancing propulsion as the kick is continued. The expansion of the pocket 3 is enhanced by the gusset 6 which expands laterally to allow entry of water and an increase in size of the pocket 3. On the return stroke, there is no water pressure internally and external pressure acts on the pocket to expel the water and to close the pocket 3. On the next kick stroke, the pocket 3 expands once more.

Referring now to Figures 4 to 7, the second embodiment of device 20 comprises a cylindrical inner member 21 which encircles the lower limb 22 of a user and has releasably fastening means in the form of eyelets 23 for receiving turn buttons of a diving boot.

There is a continuous concave pocket 24 encircling the inner member 21, formed by an integral depending skirt 25 which has longitudinally extending gussets 26 and biassing means 27 in the form of an elastic strip or strips biassing the skirt 25 towards the cylindrical member 21 which respectively form opposite sides of the pocket 24.

The cylindrical member 23 has a sliding clasp fastener 27 which enables the device 20 to be mounted on and removed from the leg of a user.

In operation, the device 20 is pulled on over a diving boot and the sliding clasp fastener 27 is fastened.

The turn buttons of the boot are inserted through eyelets 23. The device 20 then aids propulsion as in the first embodiment. On a kick stroke, Figure 6, the pocket 24 opens overcoming the force ofthe elastic strips 27 and presents an increased surface area which thrusts against the water and propels the swimmer forward. On a return stroke, Figure 7, the pocket closes, the skirt moving towards the cylindri cal member 21.

The devices 1 and 20 can be formed integrally by moulding rubber, plastics or reinforced rubber.

It will be understood that the invention shown and above described can be modified in various ways.

For example, it can be used on the arms as well as or instead of on the legs. Also, there may be means (not shown) such as straps, catches, velcro (Registered Trade Mark) or suction pads which keep the pocket 2 or 24 closed during descent to a working depth, and which can then be quickly released. Further, the fastener 27 of Figure 5 can also be replaced by Velcro or its equivalent. The device too can be used directly on a leg or foot and does not have to be attached to a boot. In this case, it is simply fashioned to have adequate securing means, for example the embodiment of Figure 1 may have ties at top and bottom for securing it to the leg.

Referring nowto Figure 8, there is shown a releasable weight 30 in the form of an extra sole which has means in the form of tension buckles 31 for securing it to lugs 32 on the foot (Figure 1). This weight 30 enables a diver to walk about underwater by weighting his feet. The weight 30 is ready attached to the boot 10 under water. When it is desired to swim, the weight30 is simply removed by releasing the catches, one of which can be used to secure the weight to a diver's belt so that it can be carried relatively easily.

Claims (8)

1. A device for enhancing propulsion when swimming, which is adapted for wearing on a limb of a user and comprises concave pocket means for entraining water on a propelling stroke of the user so as to enhance propulsion through the water.

2. A device according to Claim 1, the pocket means having means for collapsing the pocket on a return stroke.

3. A device according to Claim 1 or Claim 2, in which the collapsing means is a biassing device connecting opposite sides of the pocket and operative to draw those sides together.

4. A device according to Claim 3, the biassing device comprising an elastic strip.

5. A device according to any preceding Claim, the pocket means having a gusset extending longitudinally of the device.

6. A device according to any preceding Claim, in which the device is adapted for wearing on a limb of a user by releasable fastening means which are fastenable to a boot of a user.

7. A device according to any of Claims 1 to 6, in which the device is cylindrical for encircling a limb of a user and has a sliding clasp fastener extending longitudinally of the device for facilitating mounting of the device on that limb.

8. Adeviceforenhancing propulsion when swimming, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.