The present invention relates generally to electrical storage apparatus and particularly, but not exclusively, to apparatus having a flexible housing or sheath which can be fixed encircling a user's torso in the manner of a belt.

Apparatus for fulfilling this function is known such apparatus is loosely known in the art as a "power belt" . Known power belts comprise a flexible elongate strip for fastening around the user's waist, fitted with pockets for receiving electrical storage cells constituting the power supply. A socket into which electrical equipment to be powered can be plugged is provided, and there may be additional pockets for other equipment such as control circuitry. Such known power belts enable relatively low- power equipment, such as lamps and hand tools, to be used in places remote from a mains electricity supply and/or where the user does not wish his movements to be restricted, or hampered, by a cable connected either to the mains or to a generator or other more substantial power source.

In such known power belts, cylindrical cells are usually used and are stored in the pockets with the axes of the cells transverse the length of the belt, while the other equipment is housed in similar pockets with connecting

leads extending between the pockets within the belt to form the electrical circuit. This arrangement is generally cumbersome, requires a rather wide belt and is not very comfortable for the wearer since the housing of items of equipment in individual compartments tends to make the compartments bulky and of limited flexibility such that they press uncomfortably against the user's body and are prone to chafing. Moreover the circuit constituted by the cells and the auxiliary equipment is not readily sealed against moisture or atmospheric agents with the result that such belts cannot be used in all environments, for example, underwater or where it might become heavily soiled or contaminated in use. There is an ever-growing need for the use of electrical equipment in hostile and damp environments, and underwater, for which readily-wearable power belts are not yet available.

The present invention therefore seeks to provide apparatus incorporating a flexible housing and a flexible linked assembly of storage cells which can be incorporated in a more comfortable belt than those currently available. The invention also seeks to provide a portable power pack which can easily be sealed for use in any environment.

Accordingly, the present invention provides electrical storage apparatus comprising an elongate, flexible housing containing a plurality of cells, with contact

electrodes of opposite polarity at opposite ends arranged in end-to-end alignment in an array extending longitudinally of the housing, the cells being electrically interconnected so that the relative orientation of adjacent cells can change to accommodate flexing movements of the housing without breaking the electrical connections between them and without substantial deformation of the outer surface of the housing, and means for connecting the array of cells to an electrical load.

Preferably the cells are arranged in a row and the electrodes at the end of the row are connected to adjacent terminals at one end of the housing where a socket may be provided for receiving a plug of the electrical apparatus.

The flexible electrical storage apparatus of the invention may readily be incorporated i. a belt by the provision of end fastenings for attachment around a user's torso and, by virtue of the orientable interconnection of the cells within the housing, is more comfortable to wear than the current power belts . Moreover, since the cells and their electrical interconnections are contained within a housing, the housing may be fully sealed and made of a waterproof material so that the belt is usable underwater or in hostile environments where the belt might become soiled

or contaminated and a sealed system facilitates cleaning after use.

Preferably the housing comprises an outer casing within which is located an inner sheath which engages the cells of the array.

In a preferred embodiment the inner sheath is a shrink- fit over the cells of the array to assist in locating them in position.

It is preferred that adjacent cells of the array are interconnected physically by a resilient ligamentary connector element secured to facing surfaces of said adjacent cells.

In such a structure each said ligamentary connector encapsulates electrical connection means electrically connecting the said adjacent cells.

The electrical interconnection between the cells may be achieved in various ways such as, for example, by the provision of especially adapted, mutually cooperating electrode formations on the adjacent ends of the cells such as cup and ball formations, but it is found that connecting wires permanently secured such as by soldering at each end to the opposing ends of the cells is very effective. Such wires must not be so short as to risk

either the wire itself or the soldered joints breaking due _. to relative movements of the cells they interconnect and preferably each connecting wire is in the form of one or more turns of a coil .

The housing itself is preferably sufficiently tough to prevent damage to the cells within it in the event of accidental knocks. For some uses the housing might be made from a strong textile such as webbing but it is far more convenient to use a plastics material. A relatively thick resilient, rubber-like plastics could be used but a plastics sheath of ribbed or corrugated material is preferred. Although a metal reinforcement could be used, this may necessitate the provision of an insulating lining and therefore plastics reinforcement is preferred. The insertion of the cells into the housing is facilitated if the coil defines a substantially cylindrical inner surface rather than a corrugated inner surfac . The outer surface of the coil is preferably smoothly rounded so as not to present any sharp edges with the plastics sheath corrugated over this outer surface.

In order to enable the cells to orient themselves within the housing the cells preferably have cross-sectional dimensions substantially smaller than the internal cross sectional dimensions of the housing. Generally the cells are themselves cylindrical and of smaller diameter than

the cylindrical interior of the housing. Although the cells could simply be fitted loosely within the housing they are preferably supported within the housing, substantially centrally thereof, so they cannot move laterally to any substantial extent but can rock slightly about respective central, transverse planes. This support may be provided by one or more support members around the periphery of each cell, substantially at its longitudinal centre and projecting either from the housing wall into contact with the cell or from the cell surface into contact with the housing: the latter solution is preferred for simplicity of location of the supports. In a preferred embodiment, each cell is fitted with .a ring around its centre. Such a ring may be glued ^■ or otherwise formed on the circumferential cell surface but is preferably resilient and grips the cell elastically: a split ring is convenient. The cells fitted with their supporting rings are preferably a sliding fit within the housing, room being allowed for any wiring which extends longitudinally within the housing.

Additional electrical equipment which it is desired to be provided with the power pack may be enclosed within the housing, at one end, or may be provided in connecting members at each end of the housing. Belt fastenings for the power pack may also be attached to such connecting members although it will be appreciated that ■ the power

pack itself may have other uses apart from its _f incorporation in a power belt .

In a further aspect, the invention comprises a power belt comprising electrical storage apparatus as described above together with end fastenings attached to the ends of the flexible housing and adapted for fastening around a user's waist.

One embodiment of the invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a power belt according to the invention; Figure 2 is a longitudinal sectional view through part of the power belt of Figure 1;

Figure 2A is a perspective view illustrating an intermediate stage in the assembly of the apparatus of the invention; and Figure 2B illustrates in side view an electrical cell suitable for use in the apparatus of the invention.

With reference to the drawings, electrical storage apparatus in the form of a power pack is generally indicated 10 and includes a central, flexible, tubular housing 11 constituted by a plastics outer sheath 12 formed on a plastics helical coil 13, best seen in Figure 2. • Alternatively the helical coil 13 may be replaced by

a set of independent reinforcing rings servicing the same purpose.

Each end of the tube 11 is closed by a respective plastics connector member 14, 15 which serves as an attachment for one end of a webbing strap 16 or 17 respectively. The opposite end of the strap 16 carries a belt clip 18 which is a snap fit into a cooperating buckle member 9 attached to the strap 17. The length of the strap 17 between the connector member 15 and the buckle member 9 is adjustable in known manner so that the belt 10 can be fastened comfortably round a user's torso.

The buckle shown could of course be replaced by a fastening device of any convenient type or alternatively the straps 16 and 17 could be replaced by any other convenient form of fastening for the belt 10 to retain the tube 11 around the user's waist.

Within the tube 11 are located a plurality of generally cylindrical electrical storage cells 19 arranged in a linear array with their longitudinal axes substantially aligned with the longitudinal axis of the tube 10. The cells 19 have contact electrodes 20, 21 of opposite polarity at opposite ends and are arranged such that the facing ends of each pair of adjacent cells are constituted by electrodes of opposite polarity. These facing electrodes are interconnected by respective

electrical conductor, for example wires 22 soldered at opposite ends, at 20A, 21A respectively, to the respective contact electrode 20, 21. The free e'nd contact electrode 21 (not shown) of the cell 19 adjacent the connector member 15 is connected by a wire, not shown, to a terminal (also not shown) within this connector member while the free end contact electrode 20 of the cell 19 adjacent the opposite connector member 14 is connected by a insulated lead 24 to a further terminal (not shown) , within the connector member 15. An electrical conductor lead 24 extends longitudinally within the tube 11 from one end to the other to allow external electrical connections to be made from one end of the belt, for example via a socket 25 on one end member 15. The end terminals in the connector member 15 are connected within the member 15 itself to a socket 25 which is located on its external surface (see Figure 1) which can receive a plug for electrical apparatus to be powered by the cells 19 within the tube 11.

The cells 19 are fairly closely packed within the tube 11 but are supported against lateral movement by respective insulating rings 23, one around the circumferential centre of each cell 19. The rings 23 grip the cells 19 resiliently and locate the cell within an inner sheath 27 which, as can be seen in Figure 2, is a tight fit over the array of cells 19. The sheath 27 may be made of a heat-shrinking plastics material which has the advantage

of being electrically insulating and of assisting in physically locating the cells 19 in the array. Between each cell 19 the sheath 27 is formed with a waisted portion 28 formed by applying a suitable pressure whilst the material of the sheath 27 is softened during the heat shrinking process .

Each adjacent pair of cells 19 is also physically connected together by a ligamentary connector 29 made of a silicone rubber having adhesive properties. A suitable material is that sold by Dow Corning under reference 744RTV. This material is non-corrosive, resilient and highly adhesive. During assembly of the power belt 10 of the present invention the cells 19 are first electrically interconnected by soldering the electrical conductors 24 between adjacent electrodes at the soldering points 20A, 21A, and then a row of cells 19 is physically interconnected by the introduction of the ligamentary connectors which can be applied in a plastic state and cured to a resilient state whilst the cells 19 are held in a fixed position. A partially completed row of three cells illustrating this step in the production process is

, illustrated in Figure 2A which clearly shows the ligamentary connectors 29 joining the cells 19 to form a "spinal column" of cells.

Before the cells 19 are joined together, however, they are each fitted .with their surrounding ring 23, and at

the positive end of each cell there is provided an additional insulating collar 30 which locates firmly in a circumferential groove 31 with which such cells are provided, as is illustrated in Figure 2B. The provision of the additional insulating collar 30 assists in reducing chafing of the inner sleeve 27 when the power belt is flexed upon fitting it to a user's torso and removing it therefrom.

As best seen in Figure 2, the external surface of the tube 11 is helically grooved because of the tight fit of the plastics sheath 12 over the helical coil 13 which is formed from a plastics wire which has an arcuate profile in section towards the exterior of the coil . The internal surface of the tube 11 is, however, substantially smooth since the profile of the wire section towards the interior of the coil 13 is substantially straight and the innermost surfaces of the sheath 12 and the coil 13 lie substantially on a common cylinder when the tube 11 is straight.

In use of the belt 10, the tube 11 will be flexed when the belt is fastened initially around the user's waist and will also flex in a different manner as he moves to carry out different tasks. As the belt is flexed, each ring 23 around the centre of its cell 19 holds the cell 19 against inner wall of the tube 11 (through the sheath 27) and effectively provides a pivot point, facilitating

any movement of the cell needed to keep it in alignment with the tube axis at its particular location. This movement results in relative movement of the adjacent cells 19 in the tube 11 but such movements can be accommodated without breaking the electrical connections formed by the coiled wires 22, which are reinforced by the encapsulation within the ligamentary connectors 29. Within the limits of the flexure normally expected of the tube 11, this movement also occurs without the ends of the cells 11 pressing against the inner wall of the tube which would reduce the flexibility of the tube and/or cause a protuberance of the outside of the tube which would be uncomfortable for the wearer of the belt . The coil 13 may, in any case, be sufficiently strong to resist this deformation.

It will be appreciated that the tube 11 may be made to any length to house a required number of cells 19 for a particular usage of the power belt 10 and the tube 11 may be of any diameter according to the size of cell 19 to be housed within it. Although the tube 11 is conveniently cut to the correct length to accommodate a specific number of cells with only a selected spacing between them, end plugs may be inserted to fill unused space. Moreover, the cells 19 may themselves be of a disposable type which are usable once only in which case one or both end connector members 14, 15 may be releasably attached to the tube 11 so that the cells 19 may be replaced.

Preferably, however, the cells 19 are rechargeable in which case the connector members 14, 15 may be permanently sealed to the ends of the tube 11; such a sealed belt would then be usable, for example, in environmental conditions, such as underwater, unsuitable for an unsealed unit.

The connector members 14, 15, and particularly the latter, may be fitted with auxiliary electrical equipment, sockets or the like according to the intended use of the belt, and may house a battery recharger circuit for recharging the cells via connection to the AC main circuit.

Other embodiments (not shown) may incorporate two or more such assemblies in a common belt configuration having differently formed end members 14, 15 adapted to receive two or more tubes 11 for greater capacity.