GB2239224A - Aircraft ground-handling vehicle - Google Patents

Abstract

The vehicle, for insertion between the wheels (15) of an aircraft undercarriage, includes a body (11, 12) and undercarriage trolleys (13) connected to opposing ends of the body. A chassis (1) is pivotally mounted with respect to the body. Independently driven and controllable wheels (4) are mounted on either side of the chassis (1). The chassis can be moved between a first position in which those wheels (4) are substantially parallel to the undercarriage wheels (15) and a second position in which the wheels are substantially orthogonal to the undercarriage wheels. The chassis may be coupled to the body by an anti-friction ring bearing (7) at a common central axis. A locking mechanism (8, 9) such as a pinion in meshing engagement with the outer circumference of the ring bearing may be provided. The vehicle is particularly suitable for handling aircraft having tricycle undercarriages with fully castoring nose-wheels. Fine control of movement is achieved by differential drive of the wheels (4) while the pivot between the chassis (1) and body (11, 12) allows crab-wise manoeuvres.

Description

AIRCRAFT HANDLER The present invention relates to an aircraft handler for moving an aircraft when it is on the ground. Such a handler may be used, for example, to manoeuvre an aircraft into a hanger.

It is common practice when aircraft of a certain size and weight are on the ground, to use specially designed aircraft handlers or tractors to manoeuvre aircraft on runways, and in parking areas and hangers. It is necessary to manoeuvre the aircraft in confined spaces in order, for example, to make maximum use of the available areas in parking lots and hangers whilst maintaining freedom of aircraft movement. As well as allowing greater control in parking the aircraft the use of handlers results in considerable savings by reducing the running times of aircraft engines and their ancillary equipment.

In general, well designed, ergonomic handlers for specific tasks contribute greatly to the efficiency and cost-effectiveness of aircraft ground movement operations.

There are basically two types of aircraft handler. One type is used chiefly for manoeuvring aircraft on runways and usually consists of either a separate tractor and towing unit, or a combined tractor and towing unit.

Generally handlers of this type are powered by internal combustion engines which drive the prime mover and the towing boom manoeuvring and adjustment mechanism. A second type of handler which is smaller and lighter is used in small parking lots and service areas. This type is often pedestrian controlled manually through a combined tiller and control handle. This second smaller type of handler is usually electrically powered and suitable only for short range, low duty cycle operations.

According to the present invention, an aircraft handler for insertion between the wheels of an aircraft undercarriage comprises a handler body, undercarriage trolleys connected to opposing ends of the handler body to engage respective wheels of the undercarriage, a chassis pivotally mounted with respect to the handler body, and independently driven and controllable wheels mounted on either side of the chassis, the chassis being selectively pivotally moveable between a first position in which the independently driven wheels are substantially parallel to the undercarriage wheels and a second position in which the independently driven wheels are substantially orthogonal to the undercarriage wheels.

The present invention provides a handler which is particularly suitable for use with aircraft having tricycle undercarriages of which the nose-wheels can be set to a fully castoring position. With such aircraft the present invention provides a far higher degree of manoeuvrability than is possible with known handlers. Fine control of the direction of movement is achieved by applying differential drive to the wheels and the option of pivoting the chassis through 900 makes it possible to move the aircraft crab-wise in a direction orthogonal to its length. The combination of differential drive and selective pivoting of the chassis for the wheels provides a full 3600 of manoeuvrability.Moreover the configuration of the handler with drive applied directly to the wheels and dispensing with the conventional tiller/control-handle arrangement, makes it possible to construct the handler to handle far heavier loads than have been possible in the past.

Preferably the handler includes an anti-friction bearing coupling the body to the chassis at a common central axis and locking means provided on one of the chassis and the body and arranged to engage the other of the chassis and the body selectively to lock the chassis against rotation with respect to the body.

Preferably the bearing is a ring bearing and the locking means include a pinion in meshing engagement with the outer circumference of the ring bearing and means selectively operable to lock the pinion against rotation about its axis.

Preferably the handler includes an electric motor for each of the independently driven and controllable wheels, the electric motor being arranged to drive the wheels through a respective single input double output gearbox.

Preferably the locking means comprise two pinion wheels mounted on diametrically opposing sides of the ring bearing and a normally-ON disc brake for each pinion wheel.

In the preferred aspects of the present invention pinions with integral brakes act as pivot locks on the outer section of the ring anti-friction bearing. If, for example, at the end of a parking manoeuvre it is necessary to move the aircraft crab-wise into its final position, then the brakes on the pinions are switched OFF allowing the pinions to rotate and so freeing the chassis for pivotal movement about the bearing. The opposing set of wheels in the chassis are driven in opposite directions to swing the chassis round until it lies at 900 to the body.

The pinion brakes are then again applied locking the chassis against further pivotal movement. Drive is then again applied to the chassis wheels as appropriate to move the undercarriage and hence the aircraft sideways or in any other desired direction.

An aircraft handler in accordance with the present invention will now be described in detail with reference to the accompanying drawings in which: Figure 1 is a plan view of the handler in a first position; Figure 2 is an end elevation of the handler of Figure 1 and Figure 3 is a plan view of the handler with the chassis in an alternative position.

An aircraft handler comprises a base unit 1 which houses two electric motors 2 and, in the preferred embodiment, two single input, double output gearboxes 3.

The motors and gearboxes may form two integral units or alternatively the motors may be double-ended types each output shaft operating into a separate gearbox. This would necessitate four gearboxes, two for each motor.

The output shafts from the gearboxes are coupled to four solid-tyred traction motor wheels 4. One shaft is coupled to each wheel and the tyres are replaceable push-on types. Power for the traction or drive motors is supplied by high capacity lead acid or other secondary battery types 5. They are housed in the main base unit or "chassis".

One bank of batteries may be common to the two drive motors or alternatively two identical sets may be used, one for each motor.

Each motor is controlled by separate but identical electrical/electronic speed control units 6 located in the base unit 1. Electrical connections from each controller are routed through to the case of the base unit 1 where they terminate in a common multipin connector (not shown).

Connections to the manually operated movement controls are made through a mechanically and electrically protected cable and interface connector.

A large diameter flat anti-friction bearing 7 is mounted in a horizontal position with its rotational axis in the vertical plane in the centre of the top face of the base unit 1. The bearing may be a composite unit, i.e. two separable - one inner and one outer - sections or one complete unit of combined inseparable inner and outer sections. The inner section of the bearing is bolted to the top surface of the base unit 1 with the vertical axis directly over the intersection point of two lines each of which is drawn between the centre points of the diametrically opposed driving wheels. Gear teeth are cut in the vertical external face of the outer section of the bearing. A suitable bearing is the slewing ring ball bearing type 21/1200.2 manufactured by Roballo Engineering.

Two substantial pinion wheels 8 which rotate on subshafts are mounted in vertical positions in the top face of the base unit 1. The bearings in which the shafts run are housed in recesses in the top face. The pinions 8 are located diametrically opposed to each other across the anti-friction bearing and at right angles to the driving wheel axis. The teeth of the pinion wheels and those on the vertical face of the rim of the anti-friction bearing are in full mesh with each other. Disc brakes 9 of substantial proportions are fitted to act on a drum which forms an integral part of each pinion 8. The brakes 9 are electrically operated to the OFF position and spring returned to the ON position. The operating coils are connected in parallel with each other and therefore act in unison.Functionally the pinions 8 and the integral brakes 9 act as pivot locks on the outer section of the anti-friction bearing 7.

A metal companion structure 10 of a shape compatible with the outer section of the anti-friction bearing 7 is attached to top of the section. It may be bolted, welded or secured in any manner dependent on the construction of the outer section and the material from which it is made.

A tubular metal frame 11 is secured to the rim of the companion structure in a position which will not interfere with the free rotational movement of the structure between the pinions and integral brake units. The frame is generally rectangular in shape with longitudinal and semi-geodetic strengthening and anti-twist pieces. The frame 11 is symmetrical in plan and extends in length to the edge of the wheel cut-out section in the base unit 1.

Attached to each end of the frame 11 in the example shown are two independent triangular coupling frames 12.

The apex of each frame 12 is arranged to be mechanically connected to the castoring trolleys which support the aircraft undercarriage. The frames are connected through swivel hinges with removable pins. To accommodate aircraft having different undercarriage track widths the triangular couplings can be removed and replaced with others of the same general shape and design but of a different length appropriate to the particular undercarriage. The undercarriage trolleys 13 are simple supporting structures mounted on freely fully castoring wheels. Only two wheels 14 are shown per trolley more may be fitted if demanded by the nature of the load. In the diagram, the undercarriage wheels 15 and the undercarriage legs 16 are shown received in the trolleys 13.

In use, each of the electric traction motors drives two wheels through a common gearbox. The motors are rotationally reversable and their characteristics are identical, within normal manufacturing tolerances.

Commonality of operating characteristics although not essential to the concept of the design is preferable as regards ease of control, maintenance, and interchangeability of parts.

Electric limit switches are located in the top of the base unit. They are operated by cams or riders set in accessible positions on either the main tubular frame unit or on the outer part of the anti-friction bearing. The position of the switches is adjustable. Relative movement of the base unit with respect to the mainframe attached to the anti-friction bearing is 90" plus manufacturing and assembly tolerances. Because the drive motors are capable of running in the forward and reverse directions the 900 rotational limit is sufficient to give full 3600 ground directional control.

The running speeds of the motors are controlled independently of each other, therefore when operated at different speeds the handler can be manoeuvred or steered by using the controllers to perform the task of the conventional steering wheel or tiller. In this mode, the pinion disc brakes are ON and the inability of the pinions to rotate effectively locks the mainframe mounted on the anti-friction bearing to the base unit 1.

Sideways movement (crabbing) up to 900 with respect to the fore and aft centre line of the aircraft is achieved by unlocking the pinion brakes and setting one controller to the forward and the other controller to the reverse mode.

In this swivel mode the speed controls are automatically set to the same rate and simultaneous forward and reverse rotation of the traction wheel pairs causes the base to swivel beneath the mainframe anti-friction bearing. At the 900 rotational angle, the motors are switched off by the action of the limit switches through the speed controllers.

The base unit can be swivelled in either direction to give directional crabbing control. (Limit switches are necessary to restrict the rotational movement to 900.

Otherwise apparent control function reversal occurs i.e.

forward becomes reverse and reverse becomes forward).

The motor and brake controllers may be controlled by a system of push buttons or a central control column or joystick coupled into the base unit through a trailing cable and interface connector arrangement. Alternatively remote control may be exercised through a radio link using coded control signals. The signals are unique to each controller, thereby enabling two or more aircraft handlers to be used in the same or overlapping signal transmission areas.

In other environmentally hazardous areas, i.e. onboard aircraft carrier flightdecks or on airfields swept by high powered radar or similar radio signals, the control functions may be activated by optical devices switched by manual controls mounted on fibre optic cables through optic couplers.

In operation the triangular frames which link the mainframe to the castoring trolleys are selected to suit the aircraft type main undercarriage track. They are attached to the mainframe at detachable hinge points.

The handler is manoeuvred under the aircraft by using the crabbing control function and by steering it by means of setting the motor controls to result in different motor speeds to achieve the required turning circle. Forward and reverse, and left and right operations use common functional controls but are operated in opposite directions. When the handler is in the required position beneath the aircraft the undercarriage wheels are raised by using conventional hydraulic jacks to apply upward pressure under the legs. The handler is then manoeuvred to position the castoring trolleys centrally under the wheels and the aircraft is lowered onto the trolleys. After the hydraulic jacks have been removed, the handler is free to move the aircraft to the required location.

Claims (8)

1. An aircraft handler for insertion between the wheels of an aircraft undercarriage, the handler comprising a handler body, undercarriage trolleys connected to opposing ends of the handler body to engage respective wheels of the undercarriage, a chassis pivotally mounted with respect to the handler body, and independently driven and controllable wheels mounted on either side of the chassis, the chassis being selectively pivotally moveable between a first position in which the independently driven wheels are substantially parallel to the undercarriage wheels, and a second position in which the independently driven wheels are substantially orthogonal to the undercarriage wheels.

2. An aircraft handler according to claim 1, including an anti-friction bearing coupling the body to the chassis at a common central axis, and locking means provided on one of the chassis and the body and arranged to engage the other of the chassis and the body selectively to lock the chassis against rotation with respect to the body.

3. An aircraft handler according to claim 2, in which the anti-friction bearing is a ring bearing and the locking means include a pinion in meshing engagement with the outer circumference of the ring bearing and means selectively operable to lock the pinion against rotation about its axis.

4. An aircraft handler according to claim 3, including two pinion wheels mounted on diametrically opposing sides of the ring bearing and a normally-ON disc brake for each pinion wheel.

5. An aircraft handler according to any one of the preceding claims, including an electric motor for each of the independently driven and controllable wheels.

6. An aircraft handler according to claim 5, in which each electric motor is arranged to drive the respective wheels through a respective single input, double output gearbox.

7. An aircraft handler according to any one of the preceding claims, including releasable couplings linking the undercarriage trolleys to the ends of the handler body.

8. An aircraft handler substantially as described with respect to the accompanying drawings.