GB1568687A

GB1568687A - Underwater lifting bag

Info

Publication number: GB1568687A
Application number: GB427876A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-01-28
Filing date: 1977-01-28
Publication date: 1980-06-04

Description

(54) UNDERWATER LIFTING BAG (71) I, DAVID BRIAN THURSTON, A British subject of 16 Queen Street, Brightlingsea, Essex, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to an underwater lifting bag, that is a device which is used for lifting objects underwater.

At the present time small objects are raised t: for exasnpte, the sea bed by means of a container which is filled with air or gas w that it rides to the surface. The object to be lifted is secured beneath the container.

Divers frequently use old oil drums or similar devises but there are obviious difficulties with such cumbersome articles and the present invention is intended to provide an Underwater lifting bag which can be made in any convenient size and which is of a shape which will allow a number of such bags to nest together b lift heavy articles.

According to the present invention an under water lifting bag comprises a hollow container which is substantially impervious to air and made from a flexible material and having an upper wall which is at the top of the bag when in use which is substanflally triangular in plan view, downwardly extending side walls which depend from the sides of the upper wall, anda gas entry opening in the upper wall, one of the side walls or at the lower end of the container.

Thus, the underwater lifting bag according to the invetion is of a shape which will easily nest with similar bags but it can be used independently.

The side walls could be rectangular in shape and there could be a bottom wall but preferably the side walls are of triangular shape and are joined at their adjacent edges to provide what is essentially an euqilateral tetrahedron.

With such an arrangement the gas entry opening could be in any convenient wall but is is ,preferably triangular in plan shape at the lower end of the container, the container thus becoming a truncated equilateral tetrahedron the lower wall of which is omitted to provide the gas entry opening.

Any convenient shape with three sides can be used for the upper wall but preferably it is an eqilateral triangle.

In one convenient construction the container is made from a sheet of flexible material which is the form of a blank shaped as a substantially equilateral triangle, each side of the blank being folded upon itself about a mid point and being secured along its edge to the edge of an adjacent side.

This provides a particularly easy method of making the bag and leaves very little waste material.

Lifting lines or tapes can be secured to the lower portion of the container.

The invention may be performed in various ways but one embodiment will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a plan view of a blank of sheet flexible material from which the lifting bag according to the invention can be made; Figure 2 is a plan view from beneath of the lifting bas assembled from the blank; and, Figure 3 is a side view of the lifting bag shown in Figure 2.

In the embodiment to be described the underwater lifting bag is made from a sheet of flexible fabric material which is cut into the form of an equilateral triangle. The corners of the triangle are cut off to produce the shape shown in Figure 1. The corners of the right hand side of the blank are indicated by reference numerals A and C and a mid point in the side by reference numeral B. The corners of the lower side of the blank are indicated by reference numerals D and F and a mid point in the side by reference numeral E and the corners of the left hand side by reference numerals G and J and a mid point in that side by reference numeral H.

In order to construct the bag the side between the corners A and C is folded upon itself about the mid point B and secured together, for example by stitching or taping or other suitable means. The lower side is folded in a similar manner as is the left hand side and the fold lines acoross the blank are indicated by reference numerals 1, 2 and 3.

The result is a truncated equilateral tetrahedron as shown in Figure 2 but with the lower small triangular wall missing. The opening 4 thus produced can be used as a gas entry opening in a manner to be described.

As is shown in Figure 3 tapes are stitched or secured to the lower end of the bag and can be used for attaching articles to be lifted.

In use the bag can be carried underwater quite easily because, being made from a flexible material it can be rolled up or collapsed and thus can be made into a small package. When the diver wishes to raise an article it is merely necessary to open the bag with the gas entry opening 4 facing downwardly. The tapes 5 are secured to the article to be raised and air or gas provided from a container or a pipe-line is passed into the bag through the gas entry opening.

This ejects the water and when the bag has reached a sufficiently bouyant condition it will rise to the surface carrying the article with it If the article is too heavy to be lifted by one bag then a number of bags can be used all of which are secured to the article and due to the triangular shape of the upper wall they will nest together, thus providing the maximum- lifting capacity for the smallest plan area. In this respect it will be appreciated that if, for example, the upper wall was circular then a number of such bags placed together would occupy a much greater plan area and would provide an unweildy lifting device.

The particular shape of the blank is convenient for ease of manufacture as it can be cut from long strips and there is very little waste material, the only waste in fact, being that of the cut off corners.

A further advantage of the particular shape of the bag is that when a large number of bags are fitted together they can make a very large unit with relatively low height enabling a large lift to be undertaken in shallow water, and the shape of the bag -enatbles its -overall height to be kept low.

It will also be appreciated that as the bags can be quite small a diver can lift a large load by using the bags as small units which can be easily manoeuvered underwater. Thus a collection of bags would be made up to lift the object One diver would -have great difficulty in attaching a single large bag without help.

Although in the arrangement described above an opening at the very bottom of the container is provided the bag could if desired be made up as a complete equilateral tetra hedron and the gas entry opening made by cutting the hole in one of the sides.

Again, the downwardly depending sides could be made in the shape of a rectangle or- any other convenient shape and a bottom side could be provided. The gas entry opening could then again be made in one of the sides or in the bottom. Yet again even with rectangular sides on both sides of some other shape a bottom wall could be omitted and this could provide a gas entry opening even if the opening was quite large.

The size of the bag will of course depend upon its reqired use and it can be made-to large dimensions if desired. In such large bags the gas entry opening can be provided by a pipe which enters the top of the bag through the upper wall.

WHAT I CLAIM IS: - 1. An underwater lifting bag comprising a hollow container which - is substantially impervious to air and made from a flexible material and having an upper wall which is at the top of the bag when in use which is substantially triangular in plan view, downwardly extending side walls which depend from the sides of the upper wall, and a gas entry opening in the upper wall, one of the side walls or at the lower end of the container.

2. An underwater lifting bag as claimed in claim 1 in which the side walls are triangular shape and are joined at their adjacent edges.

3. An underwater lifting bag as claimed in claim 2 in which the gas entry opening is triangular in plan shape at the lower end of the container.

4. An underwater lifting bag as claimed in claims 1 to 3 in which the upper wall is in the shape of an equilateral triangle.

5. An underwater lifting bag as claimed in claim 4 when dependent on claim 3 in which the hollow container is in the shape of a trunkated equilateral tetrahedron the lower wall of which is omitted to provide the gas entry opening, 6. An underwater lifting bag as claimed in claim 6 in which the container is made from a sheet of flexible material which is in the form of a blank shaped as a substantially equilateral- triangle each side of the blank being folded upon itself about a mid point and being secured along its edge to the edge of an adjacent side.

7. An underwater lifting bag as claimed in claims 1 to 7 in which lifting lines or tapes are secured to the lower portion of the container.

8. An underwater lifting bag substantially as described herein with reference to and as shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. The result is a truncated equilateral tetrahedron as shown in Figure 2 but with the lower small triangular wall missing. The opening 4 thus produced can be used as a gas entry opening in a manner to be described. As is shown in Figure 3 tapes are stitched or secured to the lower end of the bag and can be used for attaching articles to be lifted. In use the bag can be carried underwater quite easily because, being made from a flexible material it can be rolled up or collapsed and thus can be made into a small package. When the diver wishes to raise an article it is merely necessary to open the bag with the gas entry opening 4 facing downwardly. The tapes 5 are secured to the article to be raised and air or gas provided from a container or a pipe-line is passed into the bag through the gas entry opening. This ejects the water and when the bag has reached a sufficiently bouyant condition it will rise to the surface carrying the article with it If the article is too heavy to be lifted by one bag then a number of bags can be used all of which are secured to the article and due to the triangular shape of the upper wall they will nest together, thus providing the maximum- lifting capacity for the smallest plan area. In this respect it will be appreciated that if, for example, the upper wall was circular then a number of such bags placed together would occupy a much greater plan area and would provide an unweildy lifting device. The particular shape of the blank is convenient for ease of manufacture as it can be cut from long strips and there is very little waste material, the only waste in fact, being that of the cut off corners. A further advantage of the particular shape of the bag is that when a large number of bags are fitted together they can make a very large unit with relatively low height enabling a large lift to be undertaken in shallow water, and the shape of the bag -enatbles its -overall height to be kept low. It will also be appreciated that as the bags can be quite small a diver can lift a large load by using the bags as small units which can be easily manoeuvered underwater. Thus a collection of bags would be made up to lift the object One diver would -have great difficulty in attaching a single large bag without help. Although in the arrangement described above an opening at the very bottom of the container is provided the bag could if desired be made up as a complete equilateral tetra hedron and the gas entry opening made by cutting the hole in one of the sides. Again, the downwardly depending sides could be made in the shape of a rectangle or- any other convenient shape and a bottom side could be provided. The gas entry opening could then again be made in one of the sides or in the bottom. Yet again even with rectangular sides on both sides of some other shape a bottom wall could be omitted and this could provide a gas entry opening even if the opening was quite large. The size of the bag will of course depend upon its reqired use and it can be made-to large dimensions if desired. In such large bags the gas entry opening can be provided by a pipe which enters the top of the bag through the upper wall. WHAT I CLAIM IS: -

1. An underwater lifting bag comprising a hollow container which - is substantially impervious to air and made from a flexible material and having an upper wall which is at the top of the bag when in use which is substantially triangular in plan view, downwardly extending side walls which depend from the sides of the upper wall, and a gas entry opening in the upper wall, one of the side walls or at the lower end of the container.

5. An underwater lifting bag as claimed in claim 4 when dependent on claim 3 in which the hollow container is in the shape of a trunkated equilateral tetrahedron the lower wall of which is omitted to provide the gas entry opening,

6. An underwater lifting bag as claimed in claim 6 in which the container is made from a sheet of flexible material which is in the form of a blank shaped as a substantially equilateral- triangle each side of the blank being folded upon itself about a mid point and being secured along its edge to the edge of an adjacent side.