US2415487A - Float - Google Patents

Description

Feb. 11, 1947. P. DUNSHEATH y 2,415,487-

FILOA'I- Filed Nm?.4 26. 1943 4 8,4 a F/G./.

lF/Gff. 29 2a 2e 27- 25 flug 21u veZt/or By# @M A ttorneys Patented Feb. 11, 1947 FLOAT Percy Dunsheath, Abinger, England, assigner to W. T. Henleys Telegraph Works Company Limited, Westcott, Dorking, England, a British Company Application November 26, 1943, Serial-No. 511,847 In Great Britain November 23', 1942 7 Claims.

This invention relates to long flexible floats for use in the manufacture of water-buoyant electric cable or for other purposes. In such cable the long flexible float generally forms a core about which are disposed one or more layers of wires constituting the cable conductor, which is usually provided with a flexible waterproof covering. For some purposes it is essential that the cable should possess a high resistance to compression in a laterall direction and yet be flexible lengthwise to permit of frequent reeling and unreeling without damage. These requirements necessitate a core that is rigid in a lateral direction but locally compressible in a longitudinal driection. obtained by making the core in part of resilient material, generally soft rubber, and in part of relatively rigid material, for instance, ebonite, wood or metal. By the present invention we' provide an alternative form of flexible float in which the need for rubber or like resilient material is very much reduced or entirely avoided. It is built up of a series of hollow cylindrical bodies each having circumferential walls of metal, plywood or a tough plastic and a pair of end walls. These containers are disposed end to end and attached to one another along the axis of the float, that is, at points lying on or in the region of the axis. A clearance'is provided between the radially outer parts of the end walls of each two succesive containers, and one (or both) of the two contiguous end walls thereof is of thin metal and sufllciently flexible to permit the containers to take up positions with their axes inclined to one another.

The invention will be further described with the aid of the accompanying drawing, wherein- Figure 1 shows, principally in elevation, a portion of a long length of a preferred formi of flexible float constructed in accordance with the invention,

Figure 2 shows, partly in elevation and partly in section, a series of hollow containers with thin metal end walls connected together in Various ways to form a portion of a further length of flexible float constructed according to the invention,

Figure'3 shows, partly in elevation and partly in section and on the same'scale as Figure 2, a

further series of hollow containers connected together in various other ways to form, in accordance with the invention, a portion'of a yet another length of flexible float constructed accordins to the invention, and

Figure 4 is an elevation of `alength'of buoyant Hitherto local compressibility has been cable embodying a flexible float of the form shown in Figure 1.

Referring first of all more particularly to Figure l of the drawingy it will be seen that the flexible float isV made up of a number of cylindrical containers I disposed end to end in axial alignment. The preferred material for these containers is tin-plate but other metals may be used, for instance, lacquered sheet iron or steel, sheet brass or sheet aluminum or, as indicated above, the circumferential walls 2 may be ofplywood or a tough plastic instead of metal. Each container l is attached to the next container along the axis of the float either at a point 3 on the axis or at a number of such points clustered around the axis. The clearance 4 is provided between the radially outer ports of the end walls 5 and 6 of each two succesive containers by making the central part of at least one of them roject outwardly beyond the radially outer part, for instance, by making it convex outwards either in the form of a flat cone as shown at 6 in Figure 1, or in the form of a shallow dome as shown in Figure 2. Of the two contiguous end walls of each container, one of them, 5, is of thin metal and sufficiently flexible to permit the twocontainers to take up a position in which their axes are inclined to one another. The other may or may not be flexible. For most purposes adequate lateral rigidity of the float and suflicient longitudinal flexibility will be obtained if the flexible end wall 5 is of the same thickness as the circumferential wall 2, but in some cases it may be advantageous to make it of thinner metal. As a flat end wall is more flexible than a conical or domed end wall, We prefer to make one end wall of each container flat and the other conica1 and to attach the flat end of one container to the conical end of the next, as shown in Figure 1, thereby obtaining adequate peripheral clearance and a highly flexible float. One or both 0f the end Walls Iwhether flat or of convex form may be rendered more flexible by providing therein one or more annular corrugations as shown at l to the right hand side of Figure 1, but this will not generally be necessary. The end walls 5 and 6 and the circumferential walls 2 may be made from separate parts and seamed together in any convenient manner as indicated at 8, for instance, in the case of containers made wholly of metal, by folding and soldering or folding and welding or folding and cementing. Alternatively, the circumferential wall and one end wall may be ntegral, being formed bya drawing, pressingor spinning operation, and the container completed by the addition of a second end wall, or the container may be formed of a pair of cupped members by seaming'the rim of one to that of the other. These two forms present the advantage that only one circumferentially extending seam is required.

The necessary clearance between the radially outer parts of adjacent containers may be obtained in one or more of several ways. As indicated above, the entire surface of one or of both of the end walls may have the form of a shallow cone with a flattened apex, or the entire surface of the end walls may be in the form of a shallow dome. Containers with end walls of the latter form are shown in Figure 2. Alternatively, both end walls of a centrally attached pair may be flat and held in spaced relationship by the means attaching them together.

The means for connecting together successive containers may vary according to the shapes of the end walls and whether only one or both are of metal. Where both are of metal and the clearance is provided by the central part of one or both of them projecting endwise beyond the radially outer part, they may be secured by soldering them together over a small area near the centre or by spot welding them at the centre, the former being preferable for containers of tinplate. Alternatively, they may be connected as shown on the extreme left of Figure 2, by providing a small hole in the centre of each wall and forcing a re-entrant edge 9 of one hole through the other and turning it over by a tool and soldering, the edge of the other hole preferably being bent over as shown at I0, or they may be bolted or riveted together by a solid rivet Il or a hollow rivetv I2. In the case where both end walls are flat, a distance piece I3 may be inserted between them, in the form of a short tube I3, through which passes the securing rivet I4, as

shown on the extreme right of Figure 2. All these securing means yet described result in a' rigid attachment of the central part of one end wall to the central part of the next. This rigid attachment does not, however, result in a rigid string of containers, for the walls, whilst being sufficiently strong in tension to maintain the cylindrical` shape of the end part of the circumferential wall under normal Working conditions, are laterally flexible and deform easily to the slight extent necessary to permit the float to bend to a reasonable curvature, the action being, in the case of a pair of curved walls in the nature of a squeezing together resulting in an increase in the length of the line of contact bei tween them rather than a change in location of the point of contact, as occurs in a true rolling action'.

In place of a rigid attachment, successive containers may be connected together by a short flexible rod, for instance, as indicated on the extreme left of Figure 3, by a short rod I5 of tough rubber having circumferential grooves I6 near each end, the diameter at the bottom of the grooves corresponding with the diameter of a central hole in each end wall 5 and 6 and the ends of the rod being rounded off so that they can be pushed through the holes to bring the edges thereof into engagement with the walls of the grooves. Instead of a flexible rod a short length of flat metal strip may be employed. Such a strip I1 is shown in Figure 3 between the second and third containers from the left. It may be secured by soldering as shown at I8 or by welding'. Where such connections are used, successivestrips in the series are preferably disposed so that they lie in planes at right angles to another. As shown in Figure 3, the flat strip I1 connecting the third to the fourth container from the left lies at right angles to that connecting the second to the third. The purpose of this arrangement is to distribute the additional flexibility imparted by the strips so that the float is substantially uniformly ilexible in all directions. Alternatively, a connector of the form shown in Figure 3 between the fourth and fifth, and fifth and sixth containers from the left may be used. This comprises a folded metal strip I9 comprising three overlying portions, the middle and one outer of which are united by a folded edge 20 and the middle and the other outer of which are united by a second folded edge 2I extending at a large angle, preferably a right angle, to the first edge. The folded strips I9 are attached to the end walls by soldering, successive strips lying at a large angle preferably an angle of to each other, as is clearly shown in Figure 3, with the object of ensuring that the oat is, as far as practicable, uniformly flexible in all directions.

`It will be appreciated that in most cases it will be necessary to attach the end walls of successive containers together before one of the containers is completed. In certain cases it may be preferable to complete the attachment of each two contiguous end walls before either ofthe two containers of which they will form part are complete so that there is access to both sides of the attachment. Where the method of attachment involves an aperture in the end walls, as, for instance, in the methods shown in Figure 2, it is advisable to seal this where possible to prevent continuous flooding of the whole string of containers. Where the ends are riveted by solid rivets, this may be effected by means of a gasket 22 between the two walls 5 and 6 which is a close fit on the rivet II, or by soldering or lacquering over the rivet on the inside surfaces of the walls as shown at 23. Where hollow rivets or eyelets are used the aperture may be plugged either in every case or at intervals along the length of the core or another form of attachment, for instance, soldering or a solid rivet may be employed at such intervals.

The containers may be filled with gas under pressure. This will serve to detect leaks present in the containers before the application of a conductorto the core and those which may arise subsequently when the cable is in service. The gas may be introduced through an appropriate aperture in the container wall which is thereafter sealed off or be generated in situ in the container by the introduction of gas-producing pellets 24. In some instances the gas may also serve to produce the desired bulging of the end walls of the container.

When the improved float is to form a core for a buoyant electric cable, it is especially desirable to keep the diameter a minimum. To this end the walls of the containers will be as thin as is compatible with the need to provide adequate support for the conductor both during the manufacture of the cable and subsequently. Forinstance, with a heavy current cable requiring a buoyant core of about three inches diameter we find that it will generally be satisfactory to construct the containers of tin-plate having a thickness of between ten mils and fourteenmils and to make the clearance between the circumferential portions of each pair of contiguous end walls approximately one quarter of an inch. Such a core may be bent round a drum of 36 inches diameter without becoming damaged. In the example of buoyant cable shown in Figure 4, the thickness of the walls of the gas-filled containers I has necessarily been exaggerated. As will be seen, the conductor comprises an inner layer 25 of wires laid up round the string of containers I and an outer layer 26 of wires laid up in the opposite direction over a separating layer 21 of rubberproofedfabric tape. This outer layer is furnished with a wrapping 28 oi similar tape and the whole provided with a tough rubber sheath 29.

It will be appreciated that in many cases it will be advantageous to use for the core of a buoyant cable or for other purposes, a float in which all the containers are of identical form and coupled together in the same way. However, it is by no means essential that this should be so and in some cases it may be advantageous to use one form of construction of container and one form of attachment in one part of the core and another form or forms in another part. For instance, parts of the float that are subjected to more severe flexing than others may be constructed of containers of which both end walls are flexible and of one or more of the forms of coupling members described with reference to Figure 3 of the drawing, whilst the remaining parts of the float may i comprise one or more of the forms described with reference to Figure 1 and Figure 2 of the draw- 111g.

What I claim as my invention is:

1. A long flexible float comprising a number of hollow cylindrical containers, each having a pair of end walls and an inflexible circumferential wall, disposed end to end with a clearance between the radially outer parts of each two successive containers, and means connecting together along the axis of the float the contiguous end walls of each two succesive containers, at least one of the two contiguous end walls of each two successive containers being of thin metal and flexible whereby to permit the containers to take up positions with their respective axes inclined to one another.

2. A long flexible float comprising a number of hollow cylindrical containers disposed end to end and each having a pair of end walls and an inflexible circumferential wall, and means for attaching said containers to one another along the axis of the float, at least one of the two contiguous end Walls of each two successive containers having a. central part projecting beyond the radially outer parts and at least one of the two contiguous end walls being of thin metal and flexible, whereby to allow the attached containers to take up positions with their respective axes inclined to one another,

3. A long flexible oat comprising a number of hollow cylindrical containers disposed end to end and each having a pair of flat end Walls and an inflexible circumferential wall, and means connecting together along the axis of the float the contiguous end walls of each two successive containers and holding the said successive containers in spaced relationship to one another, at least one of each pair of contiguous end walls of said containers being of thin metal and flexible whereby to permit the containers to take up positions with their axes inclined to one another.

4. A long flexible float comprising a number of hollow cylindrical containers, each having a pair of end walls and an inflexible circumferential wall, disposed end to end with a clearance between the radially outer parts of each pair of contiguous end walls, means for making an inflexible connection between the central parts of the contiguous end walls of successive containers, at least one of each two mutually rigidly attached end walls being of thin metal and flexible whereby to permit the containers to take up positions with their respective axes inclined to one another.

5. A long flexible float comprising a number of hollow cylindrical containers, each having a pair of end walls and an inflexible circumferential wall, disposed end to end with a clearance between the radially outer parts of each pair of contiguous end walls, and a number of discrete coupling members each of which is flexible in at least one direction and is secured at its ends to the external surfaces of the contiguous end walls of two successive containers whereby to couple said containers together along the axis of the float and hold them in spaced relationship to one another, at least one of the two contiguous end walls of said containers being of thin metal and flexible.

6. A long flexible float comprising a number of closed metal canisters each having one flexible end wall and one end wall in the form of a sha1- low cone with a flattened apex, disposed end to end with the apex of the coned end wall of each container contiguous with, and soldered to, the central part of the flexible end wall of the next container.

7. A long flexible float comprising a number of closed metal canisters, each having a pair of flat end walls at least one of which is flexible, disposed end to end so that at least one end wall of each contiguous pair is a flexible wall, and a number of coupling members each of 'which couples together the central parts of a pair of contiguous end walls, is of metal strip and comprises three overlying portions, the middle and one outer of which are united by a folded edge and the middle and the other outer of which are united by a second folded edge extending at a large angle, preferably a right angle, to the first edge, successive coupling members lying at a large angle, preferably an angle of 180.

PERCY DUNSHEATH.

le of this patent:

UNITED STATES PATENTS Number Name Date 2,180,731 Dickinson Nov. 21, 1939 411,161 Maynard Sept. 17, 1889 292,281 Brewster Jan. 22, 1884 1,403,362 Walters Jan. 10, 1922 1,667,510 Coe Apr. 24, 1928 1,810,079 Jennison June 16, 1931 1,843,452 Jennison Feb. 2, 1932 2,048,811 Peirce July 28, 1936 FOREIGN PATENTS Number Country Date 312,464 British May 30, 1929

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