WO2003009430A1

WO2003009430A1 - Apparatus and method for establishing a connection between two bodies

Info

Publication number: WO2003009430A1
Application number: PCT/GB2002/003277
Authority: WO
Inventors: Adrian Bowyer
Original assignee: University Of Bath
Priority date: 2001-07-20
Filing date: 2002-07-18
Publication date: 2003-01-30
Also published as: GB0117802D0

Abstract

There is provided an apparatus and method for establishing a connection between two bodies, the apparatus comprising two bodies. The first body defines a face including a plurality of connection points, some of which are connected to a source and some of which are connected to a sink. The second body defines a face including a plurality of connection points, each of which is connected to a positive or high pressure terminal via a substantially one-way valve in the forward direction and is simultaneously connected to a negative or low pressure terminal via a substantially one-way valve in the reverse direction. The face of the first body can be brought into contact with the face of the second body in a multiplicity of different relative positions, in each of which a connection is established between the two bodies with at least one of the source-connected connection points on the first body in contact with a connection point on the second body, and at least one of the sink-connected connection points on the first body in contact with another connection point on the second body.

Description

Apparatus and method for establishing a connection between two bodies

The present invention relates to an apparatus and method which allows a connection to be established between two touching bodies, regardless of the bodies' relative positions.

One embodiment of the invention relates to an apparatus and method which allows two-pole electrical contact to be established between two touching bodies, regardless of the bodies' relative positions. This will be referred to as the electrical embodiment.

A wide variety of apparatus for making two-pole electrical contact between two bodies are known. Perhaps the most well known of these is a plug and socket connection. In use, the plug and socket must be well aligned with respect to one another in order to establish a connection. Another known apparatus for making two-pole electrical contact between two bodies is a sliding power rail. This is commonly used in overhead wires for e.g. trains and trams, or in trackside power for electric trains and again the whole mechanism must be well aligned. A third known apparatus for making two-pole electrical contact between two bodies is a commutator or slip-ring. In this case electrical contact is made by rubbing brush contacts.

Each of the above known apparatus requires the two bodies to be well aligned, if two- pole electrical contact is to be established between them. Complicated mechanics may be required to achieve this alignment, which will add to the cost of making the apparatus and may also mean that the apparatus is liable to running problems.

An object of the present invention is to provide an apparatus and method which allows two-pole electrical contact to be established between two touching bodies and that mitigates at least some of the disadvantages described above.

A second embodiment of the invention relates to an apparatus and method which allows a similar connection to be established between the touching bodies, but in this case for the passage of fluid, for example liquid or pressurised gas. This will be referred to as the fluid-operated embodiment.

A second object of the present invention is to provide an apparatus and method which allows the passage of fluid between two touching bodies which are not necessarily well aligned.

In a first aspect, the present invention provides a contact apparatus, the apparatus comprising two bodies, a first body defining a face including a plurality of connection points wherein some of said connection points are connected to a source and some of said connection points are connected to a sink, and a second body defining a face including a plurality of connection points wherein each said connection point is connected to a positive or high pressure terminal via a substantially one-way valve in the forward direction and is simultaneously connected to a negative or low pressure terminal via a substantially one-way valve in the reverse direction, the connection points of the bodies being arranged such that the face of the first body can be brought into contact with the face of the second body in a multiplicity of different relative positions in each of which a connection is established between the two bodies with at least one of the connection points on the first body that is connected to a source in contact with a connection point on the second body, and at least one of the connection points on the first body that is connected to a sink in contact with another connection point on the second body.

In an electrical embodiment of the first aspect, the present invention provides an electrical contact apparatus, the apparatus comprising two bodies, a first body defining a face including a plurality of electrical contacts wherein some of said electrical contacts are connected to a positive connection and some of said electrical contacts are connected to a negative connection, and a second body defining a face including a plurality of electrical contacts wherein each said electrical contact is connected to a positive terminal via a diode in the forward direction and is simultaneously connected to a negative terminal via a diode in the reverse direction, the electrical contacts of the bodies being arranged such that the face of the first body can be brought into contact with the face of the second body in a multiplicity of different relative positions in each of which an electrical connection is established between the two bodies with at least one of the electrical contacts on the first body that is connected to a positive connection in contact with an electrical contact on the second body, and at least one of the electrical contacts on the first body that is connected to a negative connection in contact with another electrical contact on the second body.

It will be appreciated that whilst some of the electrical contacts on the first body are referred to a being connected to a positive connection and some of the electrical contacts on the first body are referred to as being connected to a negative connection, that should not be taken to imply that the invention is not operable with an alternating supply. In the case of an alternating supply, some of the electrical contacts on the first body can be connected to one side and some to the other side of an alternating current supply.

It is an especially advantageous feature of the invention that, as long as at least one of the positively-connected electrical contacts on the first body is in contact with an electrical contact on the second body, and at least one of the negatively-connected electrical contacts on the first body is in contact with an electrical contact on the second body, then an electrical two pole connection can be established between the two bodies. As a result no specific position of one body relative to the other is required. Preferably, the electrical contacts on the first body are separated from one another by a distance greater than the largest dimension of any of the electrical contacts on the second body. This prevents a short-circuit.

The electrical contacts on the first body and the second body may take various forms including pin-like forms but are preferably in the form of pads. However, if the electrical contacts on the first body are pin-like forms and simultaneously the electrical contacts on the second body are pin-like forms, a specific alignment will be required between the first and second body. Therefore it is inadvisable for the electrical contacts on both bodies to be pin-like forms, but rather for one or other of the electrical contact sets to be pin-like forms or neither of the electrical contact sets to be pin-like forms.

Preferably, the electrical contacts on the second body are arranged on the second body with high spatial density relative to the electrical contacts on the first body. This makes it easier to establish a connection between the two bodies.

The face of the first body which includes the plurality of electrical contacts is preferably a generally solid face with insulating material disposed between the contacts. In an alternative construction, however, gaps may be provided between the adjacent electrical contacts. Similarly, the face of the second body which includes the plurality of electrical contacts is preferably a generally solid face with insulating material disposed between the contacts. In an alternative construction, however, gaps may be provided between the adjacent electrical contacts.

In a particularly advantageous embodiment, the positively-connected electrical contacts on the face of the first body are connected together into a first region of the face and the negatively-connected electrical contacts on the face of the first body are connected together into a second region of the face and the first region and the second region are separated by a continuous non-self-intersecting curve. In one example, the curve is a Peano curve. Such curves are especially advantageous for these contacts for the following reasons:

^■ They guarantee an even distribution of positive and negative connections and a fixed minimum gap between them.

^■ They can be easily manufactured using conventional printed-circuit methods.

^■ Only two connections need to be made to cover a wide area. ■ The definition of the curves is recursive, and so they can be plotted at any scale.

^■ The recursion works at all scales. Thus, for example, square tiles with the pattern can be put together to cover a large area and will automatically connect up correctly. ■ There is an infinite range of these curves, some regular like the Peano curve and some random. They would all work well as the contact set and so give a great deal of design freedom both from the engineering and the aesthetic standpoints. In one embodiment the continuous non-self-intersecting curve is on a tile, a plurality of which tiles can be arranged adjacent to one another to form one positively- connected first region and one negatively-connected second region separated by one continuous non-self-intersecting curve.

In an embodiment of the invention, the electrical contacts on the first body are connected to a power source. If a metal object were to fall onto the electrical contacts on the first body this could result in a short circuit. One way to avoid a short-circuit is for the power source to be an electronically current limited source designed to shut down in the event of a short circuit.

Another method to avoid a short-circuit is by arranging the apparatus so that the electrical contacts on the first body are made of magnetic material and are arranged so that at equilibrium they are inset into the face and so that the second body includes a magnet. Then, when the two bodies approach one another, the magnet on the second body attracts the electrical contacts on the first body so that the electrical contacts on the first body move towards the second body and a connection is established as previously described. Any metal object that falls on the first body will not make contact with the electrical contacts on the first body, so a short circuit will be avoided. A further way of avoiding a short circuit is for the electrical contacts on the first body to be recessed into the face and the electrical contacts on the second body to be compliant so that they deform to accommodate the insulating material disposed between the contacts on the first body. In that case, the contacts on the second body may be made from conducting elastic material (e.g. silver-filled rubber) or they may be in the form of springs. This arrangement also promotes a good electrical connection. Another way to ensure a good connection is for the electrical contacts on at least one of the two types of body to be resiliently biased so that at equilibrium the electrical contacts protrude out of the body. In either case, at least some of the electrical contacts can be coated with a corrosion-resistant electrical-conducting plating, for example, gold.

In one embodiment, the second body is in the form of a wheel and the face of the second body is the perimeter of the wheel (i.e. the circumferential surface of the wheel which makes contact with the surface on which the wheel is located). In that case, the face of the first body acts as the "road" and the face of the second body can make rolling contact with the face of the first body. This will allow the second body to move freely over the first body. Each such wheel can have many diode-pair contacts on its perimeter, or, where there are two or more wheels, the whole of each wheel can be a single contact leading to a diode-pair.

In a fluid-operated embodiment of the first aspect, the present invention provides a fluid-operated contact apparatus, the apparatus comprising two bodies, a first body defining a face including a plurality of inlets and outlets wherein some of said inlets and outlets are connected to a source of fluid and some of said inlets and outlets are connected to a sink of fluid, and a second body defining a face including a plurality of inlets and outlets wherein each said inlet or outlet is connected to a high pressure terminal via a substantially one-way valve in the forward direction and is simultaneously connected to a low pressure terminal via a substantially one-way valve in the reverse direction, the inlets and outlets of the bodies being arranged such that the face of the first body can be brought into contact with the face of the second body in a multiplicity of different relative positions in each of which a connection is established between the two bodies with at least one of the inlets or outlets on the first body that is connected to a source of fluid in contact with an inlet or outlet on the second body, and at least one of the inlets or outlets on the first body that is connected to a sink of fluid in contact with another inlet or outlet on the second body.

It should be understood that where reference is made herein to a "source" of fluid and to a "sink" of fluid, the terms "source" and "sink" are to be interpreted broadly and are simply relative terms in that fluid flows from the source to the sink as a result of a pressure gradient between them; the source and sink need not be the beginning and end of the fluid flow path.

It is an especially advantageous feature of the invention that, as long as at least one of the inlet or outlets on the first body that is connected to a fluid source is in contact with an inlet or outlet on the second body, and at least one of the inlets or outlets on the first body that is connected to a fluid sink is in contact with an inlet or outlet on the second body, then a connection can be established between the two bodies. As a result no specific position of one body relative to the other is required.

Preferably, the inlets and outlets on the second body are arranged on the second body with high spatial density relative to the inlets and outlets on the first body. This makes it easier to establish a connection between the two bodies.

In the fluid operated embodiment, the fluid supply could be a constant pressure supply or a pressure-ripple supply.

The faces of the first and second bodies are preferably planar but it is within the scope of the invention for them to be curved and/or for them to be elastically deformable.

In a second aspect, the present invention provides a method of establishing a connection between two bodies, the method including the following steps: providing a first body defining a face including a plurality of connection points wherein some of said connection points are connected to a source and some of said connection points are connected to a sink, providing a second body defining a face including a plurality of connection points wherein each said connection point is connected to a positive or high pressure terminal via a substantially one-way valve in the forward direction and is simultaneously connected to a negative or low pressure terminal via a substantially one-way valve in the reverse direction, bringing the face of the first body into contact with the face of the second body in a multiplicity of different relative positions in each of which a connection is established between the two bodies with at least one of the connection points on the first body that is connected to a source in contact with a connection point on the second body, and at least one of the connection points on the first body that is connected to a sink in contact with another connection point on the second body.

In an electrical embodiment of the second aspect, the present invention provides a method of establishing electrical contact between two bodies, the method including the following steps: providing a first body defining a face including a plurality of electrical contacts wherein some of said electrical contacts are connected to a positive connection and some of said electrical contacts are connected to a negative connection, providing a second body defining a face including a plurality of electrical contacts wherein each said electrical contact is connected to a positive terminal via a diode in the forward direction and is simultaneously connected to a negative terminal via a diode in the reverse direction, bringing the face of the first body into contact with the face of the second body in a multiplicity of different relative positions in each of which an electrical connection is established between the two bodies with at least one of the electrical contacts on the first body that is connected to a positive connection in contact with an electrical contact on the second body, and at least one of the electrical contacts on the first body that is connected to a negative connection in contact with another electrical contact on the second body.

Alternatively, the first body can be provided with some of the electrical contacts being connected to one side and some to the other side of an alternating current supply.

Preferably the method also includes the step of arranging the electrical contacts on the first body such that the electrical contacts are separated by a distance greater than the largest dimension of the electrical contacts on the second body.

The method may also include the step of providing electrical contacts on either one of the first body or the second body in the form of pin-like contacts.

Preferably the method also includes the step of arranging the electrical contacts on the second body with a high spatial density relative to the electrical contacts on the first body.

In a fluid-operated embodiment of the second aspect, the present invention provides a method of establishing a connection between two bodies, the method including the following steps: providing a first body defining a face including a plurality of inlets and outlets wherein some of said inlets and outlets are connected to a source of fluid and some of said inlets and outlets are connected to a sink of fluid, providing a second body defining a face including a plurality of inlets and outlets wherein each said inlet or outlet is connected to a high pressure terminal via a substantially one-way valve in the forward direction and is simultaneously connected to a low pressure terminal via a substantially one-way valve in the reverse direction, bringing the face of the first body into contact with the face of the second body in a multiplicity of different relative positions in each of which a connection is established between the two bodies with at least one of the inlets or outlets on the first body that is connected to a source of fluid in contact with an inlet or outlet on the second body, and at least one of the inlets or outlets on the first body that is connected to a sink of fluid in contact with another inlet or outlet on the second body.

Preferably the method also includes the step of arranging the inlets and outlets on the second body with a high spatial density relative to the inlets and outlets on the first body.

While reference is made herein to the first body and second body, it should be understood that the bodies, as well as being entirely separate, could be relatively movable parts of the same structure. By way of example, an electrical embodiment of the invention will now be described with reference to the accompanying drawings, of which:

Fig. 1 is a schematic diagram of a pattern of polarised contact pads on a first body, Fig. 2 is a schematic diagram of a pattern of diode contact pads on a second body, Fig. 3a is a plan view of a first prototype of a first body according to the present invention, Fig. 3b is an underside view of the first prototype of the first body shown in Figure 3a,

Fig. 4a is an elevation view of a first prototype of a second body according to the present invention, Fig. 4b is an underside view of the first prototype of the second body shown in Figure 4a, Fig. 5 is a perspective view of the first prototype in operation.

Fig. 6 is a plan view of a second prototype of a first body according to the present invention, Fig. 7a is a perspective view of a second prototype of a second body according to the present invention Fig. 7b is a schematic diagram of the cantilever contact springs of the second prototype of the second body shown in Figure 7a, and Fig. 8 is a perspective view of the second prototype in operation. Figure 1 is a schematic diagram of a pattern of polarised contact pads 1 on a face of a first body. The polarised contact pads 1 are embedded into the face and surrounded by electrically insulating material. Approximately half of the polarised contact pads 1 are connected to the positive pole of the connection; these are the positive polarised contact pads and are designated with reference numeral 2. The remaining polarised contact pads 1 are connected to the negative pole of the connection; these are the negative polarised contact pads and are designated with reference numeral 3. The polarised contact pads 1 can be arranged in a random or regular pattern over the face and can be any shape.

Figure 2 is a schematic diagram of a pattern of diode contact pads 21 on a face of a second body. Diode contact pads 21 are embedded into the face and surrounded by electrically insulating material. Each diode contact pad 21 is connected to the positive pole of the connection 23 via a diode 25 in the forward direction such that current can only flow from the diode contact pad 21 toward the positive pole of the connection 23. Each diode contact pad 21 is also connected to the negative pole of the connection 22 via a diode 24 in the reverse direction such that current can only flow from the negative pole of the connection 22 toward the diode contact pad 21 . The diode contact pads 21 can be arranged in a regular or random arrangement over the face and can be any shape.

With reference to Figures 1 and 2, as the first body is brought into contact with the second body, some of the polarised contact pads 1 on the face of the first body come into contact with some of the diode contact pads 21 on the face of the second body. As long as contact is established between at least one positive polarised contact pad 2 and a diode contact pad 21 , and one negative polarised contact pad 3 and a diode contact pad 21 , an electric signal or electrical power can be transmitted between the first body and the second body. The more contact pads that come into contact, the better the connection.

The device will not short-circuit as long as the minimum gap between the polarised contact pads 1 (a on Figure 1) is greater than the largest dimension (in this case diameter) of each diode contact pad 21 (d on Figure 2). In this way, it will be impossible for a single diode contact pad 21 to be in contact with more than one polarised contact pad 1 simultaneously, which could result in a short circuit.

In order to establish a connection, it is possible for the polarised contact pads 1 and the diode contact pads 21 to be arranged in either a regular or random pattern. Preferably however, each of the polarised contact pads 1 is substantially the same size and shape and the spacing of the polarised contact pads from one another is preferably uniform. Similarly it is preferred that each of the diode contact pads 21 on the second body is substantially the same size and shape and the spacing of the pads from one another is preferably uniform. As long as the regular arrangement of the polarised contact pads 1 is not the same as the regular arrangement of the diode contact pads 21 (or, if it is the same, it is on a different scale), this arrangement can provide a good connection. A connection can also be established, however, if either or both sets of contact pads are arranged in a random pattern.

It is also preferable for the diode contact pads 21 to have a high spatial density relative to the polarised contact pads 1.

Figures 3a and 3b show a first prototype of a first body 31. In this exemplary prototype the first object 31 is constructed from medium-density fibreboard (MDF). A hole 32 (which is shown as rectangular in Figures 3a and 3b) is cut into the MDF. Lengths of tube 33 (for example polythene tube) are packed into the hole 32 such that the axes of the lengths of tube 33 are substantially perpendicular to the MDF surface. A similar number of lengths of solder 34 are cut with diameter such that each length of solder 34 can be easily inserted into each length of tube 33.

Orange wires 35 are soldered to the ends of approximately half the lengths of solder 34 . White wires 36 are soldered to the remaining lengths of solder 34. The lengths of solder 34 are then inserted into the lengths of polythene tube 33 such that the lengths of orange wire 35 or white wire 36 are protruding from the underside of the MDF surface (as can be seen in Figure 3b). The lengths of orange wire 35 are connected to one pole of a power source (not shown). The lengths of white wire 36 are connected to the other pole of the power source (not shown). Figure 3b shows wires connected to only some of the lengths of solder 34 for clarity, but it will be appreciated that all the lengths of solder 34 are connected to a wire, either orange 35, or white 36. Epoxy resin 37 is then poured over the entire assembly and allowed to set. Then the top side of the MDF surface is machined off, together with the set epoxy resin 37, the lengths of tube 33 and the lengths of solder 34 revealing a surface 38 of polarised contact pads 1 as substantially described above with reference to Figure 1.

Approximately half the contact pads are connected to the positive pole of the power source and the remaining contact pads are connected to the negative pole of the power source.

In the embodiment described above, the hole 32 is rectangular measuring 30mm by 40mm, the thickness of the MDF is 10 mm. Each length of polythene tube measures 8 mm and is 4 mm in diameter. Each length of solder is 6 mm in length.

Figure 4 shows a first prototype of a second body 41. In this prototype, the second body 41 is constructed from a square 42 of printed circuit board (PCB). Several small diameter holes 43 are drilled into the PCB square 42 substantially perpendicular to the surfaces 44, 45. Pairs of diodes 24, 25 are soldered together according to the configuration shown in Figure 2. Each diode pair is inserted into a hole 43 in the PCB square 42. One end of each diode pair protrudes from the surface 45 of the PCB square 42. This diode pair is then connected such that one diode is connected to the positive pole of a connection and the other diode is connected to the negative pole of the connection, as previously described with reference to Figure 2. In this prototype, the connections are connected to a light-emitting diode 46 and its current-limiting resistor (not shown).

Epoxy resin 47 is poured over the entire assembly to form a rectangular block and it is allowed to set. The second end of each diode pair protrudes from the surface 44 of the PCB square 42 and this end is cut short and level with the surface 44, revealing a surface of diode contact pads 21 as substantially described above with reference to Figure 2.

In the embodiment described above, the PCB square measures 15mm by 15mm and there are about 30 holes 43 drilled into the PCB square.

Figure 5 shows the surface 38 of the first prototype of a first body 31 in contact with the surface 44 of the prototype of a second body 41 , so that the light-emitting diode 46 lights up. The second body 41 can be located anywhere on the surface 38 of the first body and at any orientation.

Figure 6 shows a second prototype of a first body 61. In this exemplary prototype, the curve 62 is the well-known curve known as a Peano curve, but the curve could be any other continuous non-self-intersecting curve. One end of the curve 62 is at the top left of Figure 6 and the other end of the curve 62 is at the top right of Figure 6. Because the curve 62 is continuous and does not intersect itself, it defines one region to its left, 63 and another region to its right 64. All parts of the left hand region 63 are connected to one another and all parts of the right hand region 64 are connected to one another, but the left hand region 63 is not connected to the right hand region 64. At all points, the left hand region 63 is separated from the right hand region 64 by a distance equal to the width of the curve 62.

Thus, the Peano curve illustrated in Figure 6 forms a good basis for the polarised contacts. The curve is the insulating region that separates the positive (source) and the negative (sink) connections. Use of such a curve is particularly advantageous for the arrangement of the polarised contacts for the reasons given previously. As an alternative to the Peano curve, any other random or regular continuous non-self- intersecting curve may be used.

In the prototype shown in Figure 6, the polarised contact set is in the form of a Peano curve on a 270 mm square tile. A C++ program was written to generate the curve 62 as a graphics file and this was then made into a single-sided copper printed circuit board (PCB). The polarised contacts on either side of the Peano curve were nickel plated and then covered in a 2 μm gold layer to give a good contact. As mentioned above, since only two electrical connections are required to connect the entire polarised contact set, the nickel plating was particularly easy.

Figure 7a shows a second prototype of a second body 71 and Figure 7b shows part of that prototype in more detail. In the prototype shown in Figure 7a, two magnets 72 are provided on the surface 73 of the body 71. The diode contacts 74 are 0.3 mm gold- plated phosphor-bronze cantilever springs which are insulated from one another by PVC sleeving 75. This can be seen even more clearly in Figure 7b which shows one of the cantilever springs in more detail. Whilst this cantilever arrangement is not ideal for all applications (since it is somewhat delicate and easily tangled), it is simple to produce and it does introduce some compliance to the diode contacts and thereby can provide significant advantages over the first prototype shown in Figures 3 to 5. In this particular example, the second body 71 is connected to drive a quartz-halogen spotlight 76 when the polarised contact set is in contact with the diode contact set.

Figure 8 shows the second prototype in operation with the polarised contact set on the first body 61 in contact with the diode contact set on the second body 71 , so that the quartz-halogen spotlight 76 lights up. The first body 61 is arranged as a ceiling tile and is backed with a thin sheet of mild steel (not shown). In a production version of the prototype the mild steel may be replaced with a ferrite-filled polymer. The magnets 72 on the surface 73 hold the second body 71 and the quartz-halogen spotlight 76 on the ceiling tile in any position and orientation.

Such Peano curves (or other similar curves) could be made on tiles which would automatically connect together when laid over a large area. They could also be printed onto flexible film and onto a substrate with an adhesive backing.

The apparatus and method of the electrical embodiment of the invention can be of particular advantage in a number of applications where power or data needs to be transferred between two objects for example for bar-code readers, for credit and debit card transactions and other applications in which cards need to be swiped, for recharging electrical devices for example mobile telephones and cordless drills, for touch-screen applications for computers, stock control, library book issues, door locks and so forth.

Another important application of the electrical embodiment of the invention is for a road from which an electric car can pick up power whilst still being able to steer freely. In this application, the diode contact set may be on the wheels of the vehicle and the polarised contact set may be on the road, with the diode contact set making rolling contact with the polarised contact set. In practice, it may not be economic to construct a significant proportion of a real road from metal. However, existing roads are made from tar and conducting polymers are now available which use petrochemicals as the feedstock for their synthesis; it may be feasible to construct a road from them. In addition, the diode contact set may be made from a semiconducting polymer in the form of a tyre. There are, of course, many safety implications for this type of road, especially if it is run at high voltage (for example rain or people stepping onto it). This application may be especially suitable in a more structured environment for example for a toy, for automatically-guided vehicles in factories, for mobile robots used for research into cooperative behaviour or for other similar applications.

As will be apparent from the description above with reference to Figure 8, another application of the electrical embodiment of the invention is as a ceiling or wall tile. The polarised contacts may be embedded into a ceiling or wall and surrounded or backed by a polymer insulator impregnated with ferrite powder to make it magnetic. The diode set may be assembled together with magnets to clamp it to the wall or ceiling. This arrangement may be used to power spotlights (for example for galleries, exhibitions or conferences) which may be arranged at any position and any orientation, or for power cords to power any other electrical equipment.

Another application of the electrical embodiment of the invention is for desk surfaces adapted to receive a laptop computer for example. The desk surface may include the polarised contact set and the laptop may include the diode contact set. Placing the laptop on the surface may both recharge its batteries and connect it to a network without the need for wireless communication. Such an arrangement may be adapted for use in public areas such as airport lounges, aircraft or trains.

Another use of the electrical embodiment of the invention is as a full wave rectifier, in particular, if the sections of the rectifier are preferably separable and/or the rectifier is preferably able to work even with the sections misaligned. In that case, the polarised contact pads would be driven by an AC power supply and the result would be full- wave rectification of the AC supply by the diode set, with each diode pad acting as part of a diode bridge.

It will be appreciated that the above applications are simply examples and there are many further applications of the electrical embodiment of the present invention. A potential disadvantage of the electrical embodiment of the present invention in some applications is that if the polarised contact pads were connected to an electrical power source and a metal object were to fall onto the polarised contact pads, it would short them out. There are various ways in which this problem can be solved. Firstly, the power source may be an electronically current limited source designed to shut down in the event of a short circuit. Secondly, the polarised contact pads may be made of magnetic material and arranged so that at equilibrium they rest below the surface. If the body including the diode contact pads also includes a magnet, then when the two bodies are brought close to one another, the magnet will attract the polarised contact pads and thereby make a connection. If an ordinary metal object falls onto the polarised contact pads, however, it will not make contact with the polarised contact pads so there will be no short circuit. Thirdly, the polarised contacts may be recessed (preferably just slightly) in their insulator surround, and the diode contacts may be made compliant (for example from conducting rubber) such that they deform to accommodate the insulator. Then, any object falling on the polarised contacts would be supported by the intervening insulator which would stand slightly proud of the surface.

In the description above, an electrical embodiment of the invention is described. The invention can however also be applied to a fluid-operated embodiment as will be described below. The first body includes fluid passageways in place of the contact pads and connections thereto; each fluid passageway terminates in an opening at a face of the first body. Some of the passageways are connected to a fluid source and the remaining passageways are connected to a fluid sink. The passageways connected to a fluid source have ball check valves at their open ends, the valves serving to prevent fluid flow unless the open end of the fluid passageway is in contact with another body.

As will be appreciated, the second body is similarly provided with openings on a face of the body, each of those openings being connected both to a fluid passageway allowing flow in a direction through the opening into the second body and to a fluid passageway allowing flow in a direction through the opening from the second body, the flow direction being determined by one-way valves in the fluid passageways.

As in the electrical embodiment, the fluid passageways allowing flow of fluid into the second body are connected together at the downstream end and, similarly, the fluid passageways allowing flow of fluid out of the second body are connected together at the upstream end; a pneumatically operated device is, for example, connected between the two sets of connected fluid passageways (c.f. the light-emitting diode 46 of the electrical embodiment).

In the case of the fluid-operated embodiment, it is preferable to avoid undue leakage of fluid and it is therefore desirable that the faces of the first and second bodies that cooperate when contact is made between the bodies are generally solid faces interrupted only by the fluid passageways.

In the fluid-operated embodiment, the fluid can be a liquid or a gas, including for example a stream of powder particles.

Claims

CLAIMS:

1. A contact apparatus, the apparatus comprising two bodies, a first body defining a face including a plurality of connection points wherein some of said connection points are connected to a source and some of said connection points are connected to a sink, and a second body defining a face including a plurality of connection points wherein each said connection point is connected to a positive or high pressure terminal via a substantially one-way valve in the forward direction and is simultaneously connected to a negative or low pressure terminal via a substantially one-way valve in the reverse direction, the connection points of the bodies being arranged such that the face of the first body can be brought into contact with the face of the second body in a multiplicity of different relative positions in each of which a connection is established between the two bodies with at least one of the connection points on the first body that is connected to a source in contact with a connection point on the second body, and at least one of the connection points on the first body that is connected to a sink in contact with another connection point on the second body.

2. A contact apparatus according to claim 1 , wherein the connection points on the first and second body are electrical contacts and, the source is a positive connection, and the sink is a negative connection, and the positive or high pressure terminal is a positive terminal, and negative or low pressure terminal is a negative terminal, and the substantially one-way valves are electrical diodes.

3. An electrical contact apparatus according to claim 2, wherein the electrical contacts on the first body are separated from one another by a distance greater than the largest dimension of any of the electrical contacts on the second body.

4. An electrical contact apparatus according to claim 3, wherein the electrical contacts on either one of the first body or the second body are pin-like contacts.

5. An electrical contact apparatus according to claim 3 or 4, wherein the electrical contacts on the second body are arranged on the second body with high spatial density relative to the electrical contacts on the first body.

6. An electrical contact apparatus according to any one of claims 2 to 5 in which the positively-connected electrical contacts on the face of the first body are connected together into a first region of the face and the negatively-connected electrical contacts on the face of the first body are connected together into a second region of the face and in which the first region and the second region are separated by a continuous non-self-intersecting curve.

7. An electrical contact apparatus according to claim 6 in which the continuous non-self intersecting curve is a Peano curve.

8. An electrical contact apparatus according to claim 6 or 7 in which the continuous non-self-intersecting curve is on a tile, a plurality of which tiles can be arranged adjacent to one another to form one positively-connected first region and one negatively-connected second region separated by one continuous non-self- intersecting curve.

9. An electrical contact apparatus according to any one of claims 2 to 8 in which the electrical contacts on the first body are connected to a power source.

10. An electrical contact apparatus according to claim 9 in which the power source is an electronically current limited source designed to shut down in the event of a short circuit.

11. An electrical contact apparatus according to claim 9 or 10 in which the electrical contacts on the first body are made of magnetic material and are arranged so that at equilibrium they are inset into the face and in which the second body includes a magnet.

12. An electrical contact apparatus according to claim 9 or 10 in which the electrical contacts on at least one of the two types of body are resiliently biased so that at rest the electrical contacts protrude out of the body.

13. An electrical contact apparatus according to claim 9 or 10 in which the electrical contacts on the first body are recessed into the face and in which the electrical contacts on the second body are compliant.

14. An electrical contact apparatus according to claim 13 in which the electrical contacts on the second body are made from conducting elastic material.

15. An electrical contact apparatus according to claim 13 in which the electrical contacts on the second body are in the form of springs.

16. An electrical contact apparatus according to any one of claims 2 to 15 in which at least some of the electrical contacts can be coated with a corrosion-resistant electrical-conducting plating.

17. An electrical contact apparatus according to any one of claims 2 to 16 in which the second body is in the form of a wheel and the face of the second body is the perimeter of the wheel.

18. A contact apparatus according to claim 1 , wherein the connection points on the first and second body are fluid inlets and outlets and, the source is a source of fluid, and the sink is a sink of fluid, and the positive or high pressure terminal is a high pressure terminal, and the negative or low pressure terminal is a low pressure terminal.

19. A contact apparatus according to claim 18 wherein the inlets and outlets on the second body are arranged on the second body with high spatial density relative to the inlets and outlets on the first body.

20. A method of establishing a connection between two bodies, the method including the following steps: providing a first body defining a face including a plurality of connection points wherein some of said connection points are connected to a source and some of said connection points are connected to a sink, providing a second body defining a face including a plurality of connection points wherein each said connection point is connected to a positive or high pressure terminal via a substantially one-way valve in the forward direction and is simultaneously connected to a negative or low pressure terminal via a substantially one-way valve in the reverse direction, bringing the face of the first body into contact with the face of the second body in a multiplicity of different relative positions in each of which a connection is established between the two bodies with at least one of the connection points on the first body that is connected to a source in contact with a connection point on the second body, and at least one of the connection points on the first body that is connected to a sink in contact with another connection point on the second body.

21. A method according to claim 20, wherein the connection points on the first and second body are electrical contacts and, the source is a positive connection, and the sink is a negative connection, and the positive or high pressure terminal is a positive terminal, and the negative or low pressure terminal is a negative terminal, and the substantially one-way valves are electrical diodes.

22. A method according to claim 21 , also including the step of arranging the electrical contacts on the first body such that the electrical contacts are separated by a distance greater than the largest dimension of the electrical contacts on the second body.

23. A method according to claim 22, also including the step of providing electrical contacts on either one of the first body or the second body in the form of pin-like contacts.

24. A method according to claim 22 or 23, also including the step of arranging the electrical contacts on the second body with a high spatial density relative to the electrical contacts on the first body.

25. A method according to claim 20, wherein the connection points on the first and second body are fluid inlets and outlets and, the source is a source of fluid, and the sink is a sink of fluid, and the positive or high pressure terminal is a high pressure terminal, and the negative or low pressure terminal is a low pressure terminal.

26. A method according to claim 25, also including the step of arranging the inlets and outlets on the second body with a high spatial density relative to the inlets and outlets on the first body.