The present invention generally relates to a service system for at least one docking position for a craft such as an aircraft, a ship or the like, which requires the supply of various utilities, such as fuel, water, air and electric power, and the discharge of waste, such as wastewater.

Such service systems are previously known, for exam¬ ple from GB-C-2,231,073, and may comprise a plurality of service boxes lowered into the ground in the docking position, which each comprise a casing forming the side walls and the bottom of the service box, and a cover forming the top of the service box. The service boxes each accommodate a connecting device for connecting an underground supply or discharge conduit opening into the service box and connected to a utility source or a waste receiver, to a corresponding inlet or outlet of the craft.

The advantage of such a service system at an air¬ port is that the need of vehicles on the apron is eli- minated. The service boxes lowered into the ground con¬ stitute no obstacle to an aircraft on the apron, when it is not being used, but permit convenient access to, for instance, fuel, water, air and electric power, when the aircraft is parked in the docking position formed by the apron. As a result, the risk of collisions and fire on the apron is reduced. Besides, a shortened out-of-service period on the apron is rendered possible, which can be used to accomplish a better utilisation of the aircraft, i.e. a relatively seen greater amount of flying time. This implies, in turn, that the transport capacity of the airport can be increased to a considerable extent, while using the available docking positions.

The object of the present invention is to further improve a service system of the type described above, by simplifying the overhaul and repair of the system, such

that the maintenance and any repairs of the system affect the operation of the system as little as possible.

According to the invention, this object is achieved in that at least one of the service boxes comprises a cassette which is accommodated in the casing and is lift- able up from the casing when the cover is removed and in which the connecting device of the box and the associated equipment, if any, are mounted.

Owing to the inventive design, a more extensive overhaul or repair of the cassette can be carried out after it has been lifted up from the casing and replaced with a replacement cassette. The time during which the system is out of operation can thus be made extremely short, at the same time as the overhaul or repair of the raised cassette can be carried out without requiring work under pressure, the accessibility being considerably better than down in the casing.

To permit the cassette to be completely released from the service system, the connecting device of the cassette and the associated supply or discharge conduit suitably each have a coupling element adapted to be interconnected when lowering the cassette into the cas¬ ing, and to be disconnected when raising the cassette from the casing. Preferably, each coupling element has a vertical centre axis, thereby allowing the coupling ele¬ ments to take their interconnected position, when the cassette is lowered to its final position in the casing.

To prevent undesired opening of the supply or dis¬ charge conduit to the surrounding atmosphere, when the cassette is being raised from the casing, a locking means is suitably arranged for the coupling elements in the box, said locking means needing to be released, before the coupling elements can be disconnected by raising the cassette from the casing. In order to prevent also attempts to raise the cas¬ sette from the casing before the locking means has been released, a securing means can advantageously be arranged

to secure the cassette against lifting up from the casing as long as the locking means is not released. Consequent¬ ly, a non-desirable overloading of the coupling elements is prevented. At least in the case in which the supply conduit constitutes a fuel line, it can be provided, in a prefer¬ red embodiment, with a shut-off valve adjacent its coup¬ ling element, and an actuating means for the shut-off valve can be arranged to release the locking means merely in the closed position of the valve. This ensures that before raising the cassette from the casing, the shut-off valve must first be actuated to its closed position, that the locking means for the coupling elements can then be released, and that finally the securing means for the raising of the cassette from the casing can be inacti¬ vated.

In a practical embodiment of the service system, the actuating means of the shut-off valve comprises an arm which is pivotable for the shutting-off operation and which has a cam disc for generating a translational motion of the locking means.

The invention will now be described in more detail, with reference to the accompanying drawings.

Fig. 1 is a top plan view of a docking position for an aircraft, equipped with a service system according to the present invention.

Fig. 2 is a cross-sectional view along the line II-II in Fig. 1.

Fig. 3 is a perspective view of the components in- eluded in a service box in the inventive service system. Figs 4 and 5 are a front view and a side view of a coupling which is included in a service box for fuel sup¬ ply in the service system according to the invention.

Fig. 6 is a side view, partly in cross-section, of a coupling element included in the coupling according to Figs 4 and 5.

Fig. 7 is a top plan view of a coupling ring includ¬ ed in the coupling element in Fig. 6.

Fig. 8 is a block diagram of the equipment included in the service box shown in Fig. 3. Fig. 1 illustrates an aircraft 1 parked on a apron 2 of a docking position, in which passengers are exchanged, the utilities required by the aircraft are supplied and waste is discharged. More specifically, this is carried out by means of a number of service boxes 3, which are lowered into the apron in the docking position and into each of which an underground supply or discharge conduit 4 opens. Except for a fuel supply line 5, the conduits 4 are laid to a connecting chamber 6, in which they connect to collecting pipes 7 common to a plurality of docking positions and connecting the conduits 4 to a utility source and a waste receiver, respectively, in a central unit 8.

The cross-sectional view in Fig. 2 shows a service box 3, which comprises a casing 9 forming the side walls and the bottom of the service box 3, and a cover 10 form¬ ing the top of the box on the same level as the surround¬ ing ground of the apron 2. The casing 9 is, more speci¬ fically, mounted on a base 11, and the supply conduit 4 opening into the casing 9 is, in this case, intended for air for air conditioning of the passenger accommodation of the aircraft 1. Moreover, electric lines 13 extend to the casing 9, and a drain pipe 14 extends from the lowest part of the casing.

Fig. 3 illustrates the preferred construction of a service box 3 according to the invention. The service box 3 illustrated in Fig. 3 is intended for supplying fuel to the aircraft 1, but the basic composition of the service box 3 in Fig. 3 is also useful when supplying other uti¬ lities, and also when discharging waste, such as waste- water.

According to the invention, the service box 3 com¬ prises, in addition to the casing 9 and the cover 10, a

cassette 15 which carries all the equipment required for supplying fuel to the aircraft 1 from the fuel line 5 opening into the casing 9.

More specifically, the cassette 15 comprises a frame 16 with four uprights 17 of L-shaped cross-section, which are interconnected by means of a plurality of horizontal beams 18. The equipment supported by the frame 16 and thus included in the cassette 15 comprises a coupling element 19 which, together with a coupling element 20 fixedly mounted in the casing 9, forms a coupling for connecting the equipment of the cassette 15 to the fuel line 5. The equipment of the cassette 16 also comprises a pressure reducer 21, a filter 22, a fuel quantity gauge 23, a swivel connection (not shown) of a fuel filling tube 25 wound onto a tube winder 24.

The cassette 15 is lowerable into the casing 9 and liftable therefrom by means of a conventional, movable lifting device. The casing 9 has four side walls 27, which are reinforced with horizontal and vertical beams 28, and a bottom 29 with a recessed portion 30, from which the drain pipe 14 extends. At the upper edge of the inside of the side walls 27, supporting bars 31 are fixedly mounted for supporting the cover 10, such that the upper face thereof is on the same level as the sur- rounding ground of the apron 2. Adjacent the corners of the casing 9, slits 32 are formed in the supporting bars 31, said slits 32 constituting guide means for the uprights 17 of L-shaped cross-section, included in the frame 16. When lowering the cassette 15 into the casing 9, the slits 32 provide such guiding of the uprights 17 that the coupling elements 19 and 20 are directly brought into correct engagement with each other.

When the cassette 15 is in its fixed position inside the casing 9, and the cover 10 is placed on the support- ing bars 31, the cover 10 can be screwed to the casing 9 by means of screws 33. The cover 10 further comprises an openable door 34, in whose open condition the fuel fill-

ing tube 25 can be unwound from the winder 24 and the nozzle 26 can be connected to the fuel intake of the air¬ craft 1.

The above described construction of a service box 3 with the liftable cassette 15 implies a most considerable simplification on the one hand in the mounting of, in this case, the fuel filling equipment in the box 3 and, on the other hand and above all, in maintenance and repair of the fuel filling equipment. Both the mounting work and the maintenance and repair work can thus be car¬ ried out on the cassette 15 when lifted up from the cas¬ ing 9. If required, a replacement cassette (not shown) can be mounted in the casing 9, while the ordinary cas¬ sette 15 is being maintained or repaired. Thus, the dock- ing position can be used practically continuously, there¬ by making it possible to keep up the high frequency of serviced aircraft that a service system with service boxes lowered into the ground permits.

In view of the fuel being supplied in the fuel line 5 at very high pressure, it is most important that the coupling elements 19, 20 are not disconnected from each other, before the fuel line 5 has been closed against the coupling element 20. Figs 4-7 illustrate the coupling comprising the coupling elements 19, 20, and a shut-off valve 35 in the fue], line 5 adjacent the coupling element 20. This combined valve and coupling is such that a leak¬ age from the fuel line 5 via the coupling element 20 to the surrounding atmosphere is impossible. Figs 4 and 5 illustrate the coupling element 20 connected to the fuel line 5 via a shut-off valve 35 in the form of a ball valve, which i-s actuated between open and closed position by means of an arm 37 which is pivotable around a shaft 36. A cam disc 38 with a cam guiding groove 39 is fixedly connected to the arm 37. In Figs 4 and 5, the ball valve 35 is shown in its closed position, the arm 37 being ver¬ tically directed. By pivoting the arm 37 and, thus, the

cam disc 38 clockwise through 90° in Fig. 4, the valve 35 is actuated to its open position.

A plate 40 is fixed to the valve 35 and extends behind the cam disc 38 upwards along the coupling element 20. A bar 41 is mounted in vertically directed slits 32 in the plate 40 by means of bolts 43, 44, the bolt 44 extending through the guiding groove 39 of the cam disc 38.

The guiding groove 39 has a constant distance to the centre of the shaft 36 along the main part of its extent, but has at one end a portion 45 with a decreasing dis¬ tance to the centre of the shaft 36. Owing to this design of the guiding groove 39, the bar 41 will be in its upper position when pivoting the arm from the open position of the ball valve 35 to the closed position thereof, where¬ upon in continued pivoting of the arm 37 in the same direction, the bolt 44 will be pulled, by coacting with the portion 45, towards the shaft 36 and, thus, also the bar 41. Thus, the bar 41 will perform a vertical transla- tional motion during the very last part of the motion of the arm 37 in the direction away from the open position of the valve to the closed position thereof. This trans¬ lational motion of the bar 41 is used to disconnect the coupling containing the coupling elements 19 and 29. As shown in Fig. 6, the coupling elements 19 and 20 seal against one another by means of two 0-rings 46 in the interconnected position. For locking the coupling elements 19, 20 in the interconnected position, a rotat- able coupling ring 47 is mounted at the top of the coup- ling element 20, where the coupling ring 47 is secured against axial displacement between a flange 48 at the top of the coupling element 20 and an adjusting ring 49 whose axial position is fixable. As shown in Fig. 7, the coup¬ ling ring 47 has a peripheral recess 50 in a position corresponding to the bar 41, for receiving this bar 41, which thus secures the coupling ring 47 against rotation. The coupling ring 47 further comprises a number of

inwardly directed lugs 51, and the coupling element 19 has an outer flange of a form complementary to the open¬ ing of the coupling ring 47.

When the cassette 15 is lowered into the casing 9, the ball valve 35 is closed and the coupling ring 47 is in such a rotary position that the coupling element 19 is inserted into the coupling element 20 to the position illustrated in Fig. 6. Subsequently, the coupling ring 47 is rotated such that its lugs 51 block a pulling-out of the coupling element 19 from the coupling element 20, and the recess 50 is positioned in the extension of the bar 41. If the arm 37 is now rotated counterclockwise in Fig. 4, first the bar 41 will be pushed up with its uppermost part into the recess 50, whereby the rotary position of the coupling ring 47 will be locked and the coupling element 19 cannot be pulled out from the coup¬ ling element 20. Consequently, the ball valve 35 can be opened without any risk, which is carried out by pivoting the arm 37 further counterclockwise until it takes the vertically upwardly directed position as shown in Figs 4 and 5.

For indicating the stop positions of the arm 37 and, thus, the open and closed positions of the valve 35, the cam disc 38 has two carriers 52 and 53, respectively, whicn in the open position and the closed position, respectively, each actuate a limit switch 54 and 55, respectively. In this way, the position of the ball valve 35 can, of course, be indicated in the central unit 8. The carrier 52 and the limit switch 54 can also be used to actuate an electrically operated securing means 56 on the frame 16 of the cassette 15. This securing means 56 can have a piston engaging under, for example, the sup¬ porting bar 31, such that a raising of the cassette 15 out of the casing 9 is prevented by this securing means 56 as long as the limit switch 54 has not detected, under the action of the carrier 52, the closed position of the ball valve 35.

To prevent opening of the ball valve 35 when the cassette 15 has been lifted up from the casing 9, the cam disc 38 has a lug 57, which by engagement with a manually extractable lockable piston 58 prevents opening of the ball valve 35 by pivoting the arm 37 in counterclockwise direction from the closed position of the valve 35.

As shown in Fig. 8, fuel testing equipment comprises a test chamber 59 with an inlet line provided with a valve and extending from the outlet side of the filter 22, and an outlet line to a collecting chamber 60, which in turn has an outlet line opening into a venture nozzle 61 in a line parallel to the line between the pressure reducer 21 and the filter 22. By this testing equipment, the quality of the fuel supplied to an aircraft can be automatically tested, and the amount of fuel used for the testing can be returned to the inlet side of the filter 22. As a result, all manual handling of the fuel for car¬ rying out the testing is avoided.

The invention is not restricted to the embodiment described above, but is generally applicable to any medium or utility which is intended to be supplied or discharged in a docking position for practically every type of craft. Especially for aircraft, the invention thus is applicable not only to fuel, but also to elec- tricity, drinking-water, air for air conditioning, and wastewater.