GB2288373A - Wheeled vehicle for ground transport of aircraft - Google Patents

Abstract

A wheeled vehicle for transporting aircraft has an engagement and lifting unit 10 comprising a fixed member 13 and a pivoting member 14. In use, the fixed member 13 is brought into a position close to but not touching the nose wheels 9 of the aircraft. The pivoting member 14 is then closed by cylinder 20 and bars 23 and 24 are then brought into contact with the nose wheels 9. The unit 10 is then lifted relative to the vehicle's chassis. The unit 10 is connected to the chassis 1 by parallel arms 18 which enable the unit 10 to be lifted parallel to the ground and swivelled around an axis parallel to the longitudinal axis of the vehicle. <IMAGE>

Description

DESCRIPTION OF INVENTION Title: "Wheeled vehicle for ground transport of aircraft" THE PRESENT INVENTION relates to a wheeled vehicle for transporting aircraft along the ground, comprising an engagement and hoisting unit supported by the chassis of the vehicle for engagement with the nose wheels of aircraft.

It is known to use tow-vehicles with gripping devices operating with parallel telescopic arms provided with folding cross-pieces which engage the nose wheels of the aircraft from behind and hydraulically pull the towvehicle towards the nose gear. The nose-gear wheels are thus drawn either towards a scoop-like device as suggested in German Patent No. 3 318 077, or the nose wheels are drawn up on a sloping plane before being locked by the gripping arms so that they can be lifted.

The object of the invention is to provide an improved device in a vehicle for transporting aircraft on the ground, which enables the vehicle to be simply and quickly coupled to the aircraft without the latter being dislodged and without any parts having to be locked to the nose gear or its wheels prior to lifting and transport.

According to one aspect of the invention, there is provided a vehicle for transporting aircraft along the ground, the vehicle including a chassis supported by ground-engaging wheels, a hoisting unit supported by the chassis for vertical movement relative to the chassis, said hoisting unit including wheel support members adapted to be extended below the nose wheel or wheels of an aircraft respectively just in front of and just behind the point of contact of the or each said nose wheel with the ground and means for raising and lowering the hoisting unit relative to the chassis whereby after said wheel support members have been extended under the nose wheel or wheels of an aircraft in front of and behind the point of contact of said wheel or wheels with the ground, the hoisting unit can be raised relative to the chassis to lift said nose wheel or wheels off the ground, and the vehicle driven over the ground to move the aircraft with it, and whereby the hoisting unit can then be lowered to lower the nose wheel or wheels onto the ground and the wheel support members withdrawn from the vicinity of the nose wheels.

In a preferred embodiment of the invention the engagement and hoisting unit comprises two support side members spaced apart and defining a space between them to receive the aircraft nose wheels without the wheels coming into contact with the opposite surfaces of said support side members; a stationary inner counter member with an inner support surface, arranged close to ground level for engagement with lower portions of the nose wheels during said hoisting; a movable outer counter member disposed close to ground level for engagement with lower portions of the nose wheels located on the opposite side of said contact point between the nose wheels and ground in relation to said lower portions for engagement of the stationary inner counter member; a lifting means arranged to lift the engagement and hoisting unit and nose wheels from the ground upon engagement of said counter members with the nose wheels; said outer counter member being in the form of a gate pivotably journalled about a vertical axis on one of the support side members and arranged to be moved between an open position in which the nose wheels can be received within the space of said engagement and hoisting unit without contact therewith, and a closed position in which the free end of said gate is located beside and secured to the other support side member to enclose the nose wheels in said space without necessarily contacting them; said outer counter member comprising a horizontal plate with an inner, downwardly sloping support surface; said inner counter member being arranged by moving the vehicle in relation to the nose wheels to be brought into a starting position close to the nose wheels without necessarily touching them, in front of their point of contact with the ground; said inner support surface of said horizontal plate being arranged, when the gate is in closed position, to assume a starting position close to the wheels without necessarily touching them, behind their point of contact with the ground; and said engagement and hoisting unit being connected to the chassis by a plurality of parallel arms with spherical bushings on each end, enabling the engagement and hoisting unit to be lifted parallel to the ground, and also swivelled 5 -15 in each direction around an axis parallel to the longitudinal axis of the vehicle.

Besides the preferred form of device according to the present invention being considerably simpler than said known tow-vehicles, it also has the advantage over them that it avoids the technically complicated problem of having two different hydraulically operated cylinders for the telescopic arms to move exactly uniformly.

Furthermore, tow-vehicles with telescopic gripping arms must be manoeuvred straight in towards the centre of the nose gear while the arms are being retracted. If the nose gear is inclined it may be impossible to subsequently perform the locking and raising operations - the torsion link protruding between and behind the wheels on many types of aircraft is, for instance, a hindrance. In the preferred device embodying the invention the prospective lifting position can be checked before the gripping member, i.e. the gate, is operated, thereby reducing the risk of damage. The use of the known tow-vehicles with telescopic gripping arms also implies that, while the gripping arms are being retracted, unless complicated precautions are taken, the nose gear is subjected to forces that may dislodge the aircraft if the brake is not engaged.For reasons of safety, therefore, the pilot or a mechanic should assist during the pulling - in stage (for example should engage the brakes on the aircraft), thus entailing intervention in the current routines. In the case of aircraft parked at airline gates any movement inwards and forwards is more dangerous than a movement outwards and backwards. The use of tow-vehicles with telescopic gripping arms that utilize a rear scoop device on each gripping arm, similar to the construction described and down in German Patent No. 3 318 077, is limited to aircraft without deflectors (devices similar to mudguards, placed a few centimetres off the ground behind the wheels). The height of the scoop is limited to maximally about 4 cm but should preferably be less since it cannot otherwise be brought into contact with the tyres.This greatly complicates the design of the rear end pieces on the gripping arms, or implies that the tow-vehicle cannot be used on any medium-sized Douglas aircraft (DC9/ND80), these constituting a considerable proportion of the aircraft now in use. For this reason the lower part of the gate in the preferred device embodying the present invention is in the form of a horizontal plate disposed close to ground level.

Besides the complicated design of the gripping arm structure, the known arrangement, with telescopic gripping arms combined with an inclined plane, also requires the cross pieces of the gripping arms to be able to rotate during the phase of gripping when the nose wheels are pulled over, i.e., while rolling onto the inclined plane.

The nose gear will also be lifted quite considerably even during the gripping phase. If the aircraft is parked at a gate with the passenger bridge in contact with the area around the door of the aircraft, such a gripping operation cannot be performed for reasons of safety. The operation cannot therefore be commenced until the gate has been removed from the aircraft. The extra time incurred entails a deterioration of procedures both in comparison with the traditional procedure using a tractor tow-bar and with the procedure performed by the vehicle according to the present invention. There are several types of aircraft in which the nose-gear strut is not vertical. The lifting device must then be able to oscillate about a substantially horizontal axis in longitudinal direction of the towvehicle. In the known device the gripping arms, bulky even when collapsed, as well as the separate depressors required to prevent the nose gear from jumping out of position, must also take part in the oscillatory movement. The equivalent operation can be achieved in a considerably simpler manner in the preferred design embodying the present invention in which gripping arms, cross-pieces and depressors are replaced by a simple gate.

An embodiment of the invention is described in detail below with reference to the accompanying drawings, in which: Figure 1 is a view from above of a vehicle with an engagement and hoisting unit according to an embodiment of the invention.

Figure 2 is a side view of the vehicle according to Figure 1.

Figures 3 a-c are side views of an engagement and hoisting unit according to an embodiment substantially corresponding to that in the vehicle according to Figure 1.

Figure 4 is a view from above of the engagement and hoisting unit shown in Figures 3 a-c, in closed position.

Figure 5 is a view from above of the engagement and hoisting unit shown in Figures 3 a-c and 4, in semiclosed position.

Figures 1 and 2 show schematically a self-propelled vehicle for transporting aircraft (not shown) relatively short distances along the ground. The vehicle has a chassis 1 and ground-engaging wheels 6, 7. The vehicle further has a motor 2 at one end for driving the steerable wheels 6 and is provided at the other end with two longitudinal, horizontal beams 3, 4 disposed a predetermined distance from each other so that a sufficiently wide space 5 is formed between them, said space being open upwardly, downwardly and backwardly. The space 5 is thus open and accessible so that during a docking procedure the space 5 can receive the nose wheels of the nose gear of the aircraft when the vehicle is moved on its front and rear pairs of wheels 6, 7 in the longitudinal direction of the aircraft. The vehicle is provided with a cabin for the driver and operating equipment.The operating equipment may include wireguiding means enabling the driver to walk beside or behind the vehicle in order to provide a better overall view of the docking procedure and subsequent towing.

The vehicle is equipped with a device to bring it into freely supporting engagement with the nose wheels 9 as the only point of engagement, the rest of the vehicle thus having no contact or engagement with the nose gear. The device shown comprises an engagement and hoisting unit 10 which is located in the space 5 and comprises two spaced support side members 11, 12 disposed on the inner sides of the beams 3, 4, and a rear vertical transverse plate which is fixed to the rear ends of members 11, 12 and connects these members. The unit 10 is movably mounted in the chassis 1, by means of a lifting yoke 16 which is connected with the rear transverse plate via a pivot axle 17, and which yoke 16 is supported relative to the chassis by cylinders 27. The rear transverse plate, and thus the hoisting unit as a whole, is also connected with the chassis by four parallel arms 18.The parallel arms 18 have spherical bushings on their ends and enable the engagement and hoisting unit 10 to be lifted parallel to the ground, and also swivelled 50 - 150 in each direction around an axis parallel to the longitudinal axis of the vehicle. The engagement and hoisting unit 10 further comprises an inner counter member 13 rigidly or adjustably connected to the support side members 11, 12 or to the rear transverse plate and having an inner, concave support surface with a contour substantially corresponding to the radius of the nose wheels of the aircraft to be moved. The inner counter member 13 may be adjustable to different sizes of nose wheels 9. Thus, it may be supported by hydraulic cylinders which adjust the position of the counter member as desired.The engagement and hoisting unit 10 is also provided with a movable outer counter member 14 in the form of a gate movable into a position in which it closes the space 15 between the support side members 11, 12. The gate 14 is pivotably suspended on a vertical shaft 28 on one support side member 12 enabling it to be swung about a vertical axis from an open position in which it extends along one chassis beam, to a closed position in which the free end of the gate 14 is located in the vicinity of the other support side member 11 and can be locked in place by means of a suitable locking device 19, e.g. including a hydraulic cylinder that can pull the gate 14 into a groove in the support side member 11.The swinging movement of the gate 14 is achieved with the aid of a pneumatic or hydraulic cylinder 20, the ~~~~~~~~~~ piston rod 21 thereof being pivotably connected to a link arm 22 which is in turn rigidly connected, i.e. fixed to the gate 14. The gate is provided with two upper supports 23, suitably in the form of horizontal bars. The bars 23 are arranged to be brought int abutmant with upper parts of the nose wheels 9. Another bar 24 swings around pivots 25 on the inside of the support side members 11, 12 and is arranged to be hydraulically brought in abutment with the upper parts of the nose wheels 9 of the aircraft. The gate 14 comprises a horizontal plate 33 having a support surface 26 arranged opposite the lower part of the inner concave support surface of the inner counter member 13.

When the vehicle has been driven into position in front of the nose wheels 9, the driver opens the gate 14 and drives the vehicle further forward so that the beams 3, 4 straddle the nose wheels 9, the wheels thus being accommodated in the space 5. The vehicle is moved so far in a first stage that the nose wheels 9 are located between the support side members 11, 12 and at a distance of about 300-100 mm from the concave support surface of the stationary inner counter member 13. There is sufficient space between the support side members 11, 12 for the centre line of the nose wheels 9 to be displaced approximately +70 mm from the centre line of the engagement and hoisting unit 10.In a second stage the vehicle is then moved slowly so that the distance between the concave support surface of the inner counter member 13 and the nose wheels 9 is reduced to approximately 3 mm.

This distance is not critical but it is neither necessary nor desirable for the nose wheels 9 to come into contact with said support surface at this stage.The gate 14 is then closed with the aid of the cylinder 20 and secured in closed position by means of the locking device 19. Then the bars 23 and 24 are brought into contact with the nose wheels 9. The engagement and hoisting unit 10 then hoists the nose wheels 9 with the aid of hydraulic cylinders 27 acting upon the yoke 16, and connected to the chassis 1, whereupon the inner counter member 13 and plate 33 are brought into free-supporting engagement with facing lower portions 29, 30 of the nose-wheel treads 31 located on both sides of the point of contact 32 with the ground.

The nose wheels 9 will thus be raised about 15-50 mm off the ground in the case of an aircraft with vertical nose gear and about 100 mm in the case of an aircraft with inclined nose gear. The aircraft is now ready for towing to the desired position where the tow-vehicle's engagement and hoisting unit 10 is released from the nose wheels 9 by performing the procedure described above in the reverse order.

Claims (8)

1. A vehicle for transporting aircraft along the ground, the vehicle including a chassis supported by ground-engaging wheels, a hoisting unit supported by the chassis for vertical movement relative to the chassis, said hoisting unit including wheel support members adapted to be extended below the nose wheel or wheels of an aircraft respectively just in front of and just behind the point of contact of the or each said nose wheel with the ground and means for raising and lowering the hoisting unit relative to the chassis whereby after said wheel support members have been extended under the nose wheel or wheels of an aircraft in front of and behind the point of contact of said wheel or wheels with the ground, the hoisting unit can be raised relative to the chassis to lift said nose wheel or wheels off the ground, and the vehicle driven over the ground to move the aircraft with it, and whereby the hoisting unit can then be lowered to lower the nose wheel or wheels onto the ground and the wheel support members withdrawn from the vicinity of the nose wheels.

2. A vehicle according to claim 1 wherein the vehicle has a normal direction of travel determined by said ground engaging wheels, and said wheel support members, in the aircraft-transporting position thereof, extend generally perpendicular to said direction of travel.

3. A vehicle according to claim 2, wherein said hoisting unit is disposed adjacent one end of the vehicle end, said wheel engaging members include a first member and a second member which in one position thereof extends parallel to said first member and closer to said one end of the vehicle than said first member and a second position in which it is displaced to one side of the vehicle whereby the vehicle can be driven up to the nose wheel or wheels of an aircraft with said second wheel engaging member in said second position thereof, until said first member lies below said nose wheel or wheels, directly behind the point of contact of said nose wheel or wheels with the ground, and said second wheel engaging member can then be moved to said first position thereof to lie below the nose wheel or wheels in front of the point of contact of the latter with the ground prior to raising the hoisting unit and with it said wheel supporting members and said nose wheel or wheels.

4. A wheeled vehicle for transporting aircraft on the ground, comprising an engagement and hoisting unit (10) supported by the chassis (1) of the vehicle and arranged to be raised from a starting position in order, when in free surface contact with the nose wheels (9) of the aircraft on both sides of the contact point between nose wheels (9) and ground, to be brought into releasable engagement with the nose wheels (9) so that they are lifted simultaneously from the ground, characterized in that said engagement and hoisting unit (10) comprises two support side members (11, 12) spaced apart and defining a space (15) between them to receive the nose wheels (9) without their coming into contact with the opposite surfaces of said support side members (11, 12); a stationary inner counter member (13) with an inner support surface, arranged close to ground level for engagement with lower portions (29) of the nose wheels (9) during said hoisting; a movable outer counter member (14) disposed close to ground level for engagement with lower portions (30) of the nose wheels (9) located on the opposite side of said contact point between the nose wheels (9) and ground in relation to said lower portions for engagement of the stationary inner counter member (13); a lifting means (27) arranged to lift the engagement and hoisting unit (10) and nose wheels (9) from the ground upon engagement of said counter members (13, 14) with the nose wheels (9); said outer counter member (14) being in the form of a gate pivotably journalled about a vertical axis (28) on one (12) of the support side members and arranged to be moved between an open position in which the nose wheels (9) can be received within the space (15) of said engagement and hoisting unit without contact therewith, and a closed position in which the free end of said gate (14) is located beside and secured to the other support side member (11) to enclose the nose wheels (9) in said space (15) without necessarily contacting them; said outer counter member (14) comprising a horizontal plate (33) with an inner, downwardly sloping support surface; said inner counter member (13) being arranged by moving the vehicle in relation to the nose wheels (9) to be brought into a starting position close to the nose wheels (9) without necessarily touching them, in front of their point of contact with the ground; said inner support surface of said horizontal plate (33) being arranged, when the gate (14) is in closed position, to assume a starting position close to the wheels (9) without necessarily touching them, behind their point (32) of contact with the ground; and said engagement and hoisting unit (10) being connected to the chassis (1) by a plurality of parallel arms (18) with spherical bushings on each end, enabling the engagement and hoisting unit (10) to be lifted parallel to the ground, and also swivelled 5 -15 in each direction around an axis parallel to the longitudinal axis of the vehicle.

5. A vehicle as recited in claim 4, characterised in that said gate (14) is provided with horizontal upper supports arranged to be brought into engagement with upper portions of the nose wheels (9) in the closed position of said gate.

6. A vehicle as recited in claim 4, characterised in that said engagement and hoisting unit (10) is arranged to be lifted with the aid of said lifting gear so that the nose wheels (9) are raised to a transport position about 15-100 mm above ground level.

7. A vehicle for transporting aircraft, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

8. Any novel feature or combination of features described herein.