Background of the Invention A conventional aircraft self propelled handler typically has a wheeled rectangular body having a pair of jaws at the front of the body which can clamp against the opposite sides of the tyres on the wheel or wheels of an undercarriage, typically the front undercarriage and lift the wheel (s) off the ground, to effect a handling operation for example a tow. A problem with the use of clamping jaws for lifting aircraft by the tyre (s) is that pairs of jaws need to be shaped specifically for use in lifting particular aircraft. Furthermore the shape of an aircraft tyre will vary according to different parameters such tyre pressure, temperature and the weather. If the tyre is flat the lifting jaws cannot be used in lifting and manoeuvring the aircraft.

Pairs of clamping jaws are also relatively expensive to manufacture Another problem associated with the use of clamping jaws is that the handler may require several attempts manoeuvring around the undercarriage before it is correctly position for the lifting operation The present invention provides an aircraft handler which is easily aligned relative to an undercarriage for a lifting and/or towing operation.

Statements of Invention According to the present invention there is provided a lifting tool for engaging with a portion of an object to be lifted, the lifting tool having a body with a cavity therein filled with a plurality of closely packed pins which provide load bearing surfaces which in use engage a portion of said object, the pins being individually axially displaceable within the cavity to permit limited movement of at least some of said pins on insertion of said portion into the cavity with other pins surrounding said portion providing support and transferring the lift load to the surrounding body.

By axially displaceable is meant along the longitudinal axis of the pins.

The pins may be of any suitable cross-section which facilitates their close packing and may be circular in section or polygonal, preferably square or hexagonal.

Preferably, the pins are resiliently biased outwardly of the cavity and have outer end faces which together form a substantially planar surface. Any one pin when at maximum inward displacement is supported at least in part by the surrounding adjacent pins.

The inner ends of the pins are slidably mounted to the base of the cavity. The base of the cavity may be detachable from the body allowing the pins and base to be removed and attached as a single sub-assembly.

The cavity may be any desired shape and is preferably hexagonal in section and the pins may have either a circular or hexagonal section. In use two of the-sides of said hexagonal cavity are substantially horizontal and when using circular pins, at least the other sides may be provided with arcuate concave recesses to accommodate an adjacent pin.

According to a second aspect of the present invention there is provide a lifting apparatus comprising a pair of lifting tools according to the first aspect of the Invention and which in use engage opposite end portions of an object to be lifted.

The apparatus comprises a ground standing body with a pair of lifting arms pivotally mounted on the body for rotation about a substantially horizontal axis to lower or lift the distal end of the arms, each arm being provided with a lifting tool at its distal end, the two arms also being pivoted around a second axis, normal to the horizontal axis, for movement of the lifting tools towards or away from each other.

A third aspect of the invention provided an aircraft handler for use with the undercarriage of an aircraft, and which includes lifting apparatus as disclosed above.

Preferably, the handler is self-propelled and comprises a generally"Ut'shaped ground standing body having a pair of arms linked by a bridge at one end thereof with a pair of drive wheels located one at the free end of each arm, at least one wheel located adjacent the bridge, with a pair of lifting arms being pivoted to the two arms of the body and located between the drive wheels. A similar aircraft handler is disclosed in GB-A-2391 205.

The lifting arms may be mounted on a bar extending between the two arms of the body or alternatively on a pair of coaxial stub axles mounted one on each arm. The opposite ends of said bar or stub axles are provided with radial lugs and actuators acting between a respective arm of the body and lug. rotate the bar or respective stub axles to raise or lower the lifting arms.

In another embodiment, the bar may extend between two stub axles.

Where the lifting arms are mounted directly on a respective stub axle, each lifting arm is held rotationally fast in one orthogonal axis in a diametral slot in the inner end of each respective stub axle and is pivoted to the respective stub axle in the other orthogonal axis normal to the slot.

The lifting arms preferably each comprise a pair of substantially parallel struts each of which is pivoted at one end to the lifting tool. The other ends of the two struts may be pivotally conncted to a respective stub axle thereby forming a four bar parallelogram linkage which ensures that the lifting tools remain substantially horizontal during their lifting and lowering movements.

In an alternative arrangement, the lifting arms may form part of a sub-assembly mounted on said bar. The sub-assembly may include a support strut pivotally mounted at its mid point to the bar along an axis normal to both the horizontal and second axes with the other ends of the two lifting arm struts pivotally connected to opposite ends of said support strut forming part of a four bar parallelogram linkage which ensures that the lifting tools remain substantially in the plane of the support strut during their lifting and lowering movements.

Actuators are operable to move the arms towards or away from each other.

The lifting apparatus may also further. include adaptor means which engages the object to be lifted and which have a spigot thereon which is engagable within the cavity of the lifting tool.

For applying a lifting load to aircraft undercarriages, the adaptor means may comprise a disc having a first coaxial spigot to one side thereof and which is engagable within the cavity of the lifting tool and a second coaxial spigot on the other side thereof for engaging a cavity a tow point on the undercarriage. Such tow points may be provided in the ends of the aircraft wheel axle or a reinforced section of the undercarriage structure.

A further aspect of the invention provides a method of application of a lifting load to an object in which a lifting apparatus according to a second aspect of the present invention is caused to engage opposed portions of the object to be lifted when on the ground, said opposed portions being accommodated within the respective cavities of the lifting tools, and supported on the surrounding pins, and then applying a lifting load to said object.

An advantage of said method is that the opposed portions to which the lift load is applied do not need to be exactly in alignment with each other, or with the centres of the cavities in the lifting tools since the pins within the cavity are displaceable to accommodate the lift portion at any location within the cavity, and the surrounding close packed pins provide the necessary support during the lift.

Yet another aspect of the present invention also provides a method of application of a lifting load to an aircraft undercarriage in which method adaptor means is inserted one on each side of a tow point on an aircraft undercarriage and an aircraft handler according to a third aspect of the invention is operated so that the two lifting tools each engage a respective adaptor means for application of a lifting Load.

Description of the Drawings The invention will be described by way of example and with reference to the accompanying drawings in which : Fig. 1 is a plan view of an aircraft handler according to the present invention.

Fig. 2 is a cross-sectional view take on the centre line CL of the handler of Fig. l Fig. 3 is an enlarged fragment of Fig. 1, Fig. 4 is a view of adaptor used with the handLe as is shown in Figs. 1 Fig. 5 is a second view of the adaptor, Fig. 6 is a front view of the body of the lifting tool used with the handler, Fig. 7 is a sectional view of the lifting tool taken on the line VII-VII of Fig 6, Fig. 8 is a rear view of the lifting tool, Fig. 9 is a side elevation of a pin.

Fig. 10 is an isometric view of a further lifting apparatus in accordance with the invention, Fig. 11 is a plan view of the apparatus of Fig. 1 0, Fig. 12 is a side view of the apparatus of Fig. 1 0, and Fig. 13 is an isometric view of an aircraft hancLler incorporating the lifting apparatus of Fig. 10.

Detailed Description of the Invention With reference to Figs 1 to 3 of the drawings, there is shown an aircraft handler which is for use in co-operation with an undercarriage of an aircraft, particularly the front undercarriage, and is more particularly for use with a helicopter nose wheel. The handler is self-propelled a nd can exert a maximum lifting load of between 3-5 tonne. The handler is similar to handlers described in GB-A-2391 205 the contents of which are hereby incorporated into the present description.

The handler 10 has a body or chassis 11 which in plan view is substantially"U"shaped or horseshoe shaped having two arms 12 & 13 linked by a bridge 14. The body 10 stands on wheels 15, 16 17,18, the wheels 15 & 16 being located at the end portion of each respective arm 12 & 13, and the wheel 17 & L8 are located one to each side of the bridge 14. The bridge 14 is lower than the arms 12 & 13 having a height of about 220mm as compared with the height of the arms which is about 360mm_ The fronts 12 & 13 of the arms are inclined or chamfered so that the handler lies substantially within a pitch circle struck from the intersection of the centre line CL and the axis of rotation of lifting arms 51 to be described later.

Keeping the handler profile within a small pitch circle allows for manoeuvrability whilst under the aircraft.

Each of the chassis arms 12 and 13 is formed from two portions, a respective upwardly facing front compartment 32 and 33 adjacent the bridge 14, and a raised flat end portion 34 and 35 having a height which is substantially equal to the height of the respective arm. The front compartments 32,33 each house a plurality of battery cells 36 which provide power for the handler 10. The bridge 14 is hollow and houses a battery charger 38 for recharging the battery cells 36, and a pair of interlinked programmable microprocessor units 37,'39.

The front compartment 33 of the arm 13 also houses an isolator 41 for the batteries, a DC/DC converter 40 for supplying power to the microprocessors, and a main power contact switch for supplying power to the handler. The front compartment 32 on the arm 12 also houses an electrically powered hydraulic pump 42 and associated control valves 43, the pump 42 being powered by the batteries 36. The compartments 32,33 may be closed by a removable lid 136 as shown in Fig. 13.

The wheels 17 & 18 are located at the front of the handler 10, the wheel 18 being a swivel castor wheel and the wheel 17 being a steerable wheel mounted on a rotatable plate 23 for steering in a similar manner to that described in GB-A-2391 205. Optionally, both wheels 17 & 18 may be steerable.

The wheels 15 and 16 are drive wheels driven by in-wheel drive motors 26 arranged coaxially of the wheel. Each drive motor 26 is a DC powered unit driving its respective wheel through a gearbox. Electro-magnetic brake units 27 are also mounted coaxially of the wheels on the respective motors 26. The operation of the drive motors 26 and brakes 27 for movement of the handler is controlled through the microprocessor units 37,39.

The wheels are fixed and the handler is steered by said motors driving the two wheels at different rotational speeds and/or by means of the steerable wheel (s) 17 & 18.

Referring particularly to Fig. 3, the lifting arms 51 are located between the two chassis arms 12 & 13 in opposition to each other and are each pivoted to a stub axle 52 which is mounted for rotation to a respective arm 12 or 13. The two stub axles 52 are coaxial and rotate about a horizontal axis with the respective lifting arms 51 held rotationally fast in one orthogonal axis. The outer ends of the respective stub axles 52 are located within the respective compartments 32,33, and are provided with respective radial lugs 56 which are each connected to a respective hydraulic actuator 57 located within the compartment and extending between the respective lug 56 and a bracket 58 on the respective arm 12 or 13. Operation of the two actuators 57 rotates the two stub axles 52 raising or lowering the lifting arms 51. The actuator 57 extends to raise the arms 51.

The two stub axles 52 are located substantially at the centre of gravity of the handler 10.

The two lifting arms 51 each comprise a pair substantially parallel struts 61,62 which are located in a diametral slot 73 in the inner end of each respective stub axle 52. The two struts 61,62 are held rotationally fast in axis of rotation by the sides of the slot 73 and are pivoted to the respective stub axle 52 at one end thereof in the other orthogonal axis by pins 63,64 which are normal to the slot 73. The other ends of the two struts 61,62 are pivoted by pins 65,66 to a lifting tool 100. The pivot pins 65,66 are substantially parallel to the pins 63,64 and the respective stub axle 52, struts 61,62 and lifting tool 100 form a parallelogram four bar linkage which in use holds the lifting tools 100 substantially horizontal.

An actuator 68 is operable between the outer struts 62 of the support arms 51 to move the lifting tools 100 closer together or further apart. In an alternative arrangement, also shown, a pair of actuators 67 may act between an anchor 69 on the chassis 11 and a respective outer strut 62.

The hydraulic actuators 57,67 and 68 are connected by hydraulic hoses (not shown) to the control valves 43 which axe in turn operated through the microprocessors 37,39. The hydraulic system is provided with a pressure relief valve (not shown) which limits the maximum lifting load provided by the handler 10. The hydraulic pressure acting in the two actuators 57 and 67 should be equalised by suitable means.

With reference now also Figs 6 to 9, each lifting tool 100 comprises a cylindrical body 101 which has a radial flange 102 secured to its outer cylindrical surface by for example welding. The lifting tool is secured to the struts 61, 62 by means of the flange 102. The lifting tool is illustrated as attached to the lifting arm 51 and is also shown in a detached condition with an adaptor 120 to be described later.

The body 101 has a cavity 103 formed therein which has a base 104 which in this embodiment is detachable from the main body.

The cavity 103 may be any suitable cross-sectional shape, for example circular or polygonal e. g. hexagonal as in the present example. The cavity 103 houses an array of close packed pins 105 which are each in contact with their neighbours. The pins 105 extend axially of the cavity 103 and have a larger diameter head 106 and smaller diameter stem 107. The stems 107 of the pins pass slidingly through respective apertures 108 in the base 104. The outer ends of the stem 107 are provided with abutments 118 that limit the movement of the pins towards the mouth of the cavity 103 under a bias load exerted by coil springs 109 located coaxially around each stem 107 and acting between the base 104 and the respective pin head 106. Each pin 105 may be displaced individually under load inwardly of the cavity 103.

The pins 105 may be any suitable cross-sectional shape that permits a close packing arrangement. In the present embodiment, the hexagonal cavity is about 90mm across flats and houses one hundred and forty circular section pins 105 about 8mm in dia. and which are formed into a close packed hexagonal array. The cavity 103 may be formed with sides 110 having recesses which are shaped to accommodate the adjacent pin, in this example concave arcuate recesses. The array of pins comprises thirteen horizontal rows and fourteen diagonal rows.

In another embodiment not shown, those sides which in use form the substantially horizontal upper and bottom sides 110A, 110B may be planar.

The base 104 and pins 105 may form a sub-assembly which can be removed from and assembled to the circular body 101 as a unit.

The heads 106 of the pins have a sufficient axial length that when a pin 105A is in a fully retracted condition, as shown in Fig. 7, its head 106A is supported by the heads 106 of the surrounding pins.

The pins 105 have respective end faces 112 which all align one with another to form a planar surface across the mouth of the cavity 103.

In some applications it may be necessary to use the lifting tool 100 in combination with an adaptor 120 an example of which is shown in Figs 4 and 5. The present adaptor 120 is basically a steel disc 200 having a coaxial hexagonal stud 201 on one side thereof and a coaxial stepped diameter cylindrical stud 202 on the other side thereof. The stud 202 has its larger diameter portion 203 adjacent the disc and smaller diameter portion 204 outwardly thereof. In use the smaller diameter portion 204 is inserted into a hole in a tow point of an aircraft undercarriage, for example, the nose wheel axle 300 (see Fig. 3). The larger diameter portion 1203 abuts the axle end face and ensures that the disc 200 is spaced from the tow point. When using the wheel axle 302 as a tow point, this prevents side loads being exerted on the wheel bearings.

The dimensions of the studs 201,202 will be determined by the size of the tow points and by the load to be lifted. In order to provide a 3 Tonne lift, the stud portion 204 may be 18mm in dia. and the hexagonal stud may be about 25mm across flats.

It may be necessary to have different adaptors for different aircraft, or other lifting applications.

The adaptors may be provided with means for preventing the adaptors from dislodging during the lifting process. For example the stud 202 may be magnetized or its smaller diameter portion provided with spring loaded radial grips.

In use, the smaller diameter portions 204 of a pair of adaptors 120 are inserted into blind bores 301 in opposite ends of the axle 300 of an aircraft nose wheel 302 and are held in place by magnetism.

The handler 10 is controlled through the microprocessors 37,39 which control the speeds of the drive wheels 15,16, the angle of the steerable wheel 17, and the operation of the lifting arms 51. In use, the handler is manoeuvred, by an operator using a remote hand set, under the nose of an aircraft and the lifting arms 51 are operated to cause the lifting tools 100 to engage with the two adaptors 120.

The lifting tools 100 are caused to close and the hexagonal studs 201 are received in the cavities 103 of the two opposed lifting tools 100. Pins 105 contacted by the studs 201 are pushed into the cavity until the heads 106 of the pins bottom on their springs 109. The other surrounding pins remain biased fully outwardly. Since the cavity 103 is about 90mm across its flats and the stud 201 is about 25mm across its flats, it will be apparent that the axis of the cavity need not be aligned with the axis of the stud 201 and aircraft axle. Furthermore the two lifting tools 100 need not be perfectly aligned with each other.

When an initial lift load is applied through the lifting arms 51, the lifting tools 100 will rise to take up any play between the surrounding pins and the stud 201 until a light load is being transferred from the lifting tool body 101 through the closely packed pins 105 to the stud 201.

An increased lifting load will be transferred through the closely packed pins 105 to the stud 201, through the adaptor 120 and to the aircraft undercarriage. The pins immediately surrounding the studs 201 provide load bearing surfaces transferring the lifting load from the lifting tool body 101 to the aircraft tow point.

The lift load causes a downward reaction force on the handler 10 which increases the traction between the handler wheels and the ground. The lift load may, but not necessarily, cause the nose wheel 302 to be raised from the ground. The aircraft can then be manoeuvred using the self propelled handler 10 as is required under the control of an operator.

In other embodiments not shown, the pins 105 may have other cross-sections, such as square or hexagonal, that permit close packing into a substantially continuous array. The cross- section of the cavity 103 may adapted to other shapes to suit the selected shape of pin.

The adaptors 120 may be other shapes and the hexagonal stud 201 may be replaced by a cylindrical stud which could be dimensioned to fit alternative size tow points thereby allowing an adaptor to be utilised for at least two different types of aircraft.

In yet another embodiment and as disclosed in GB 2391 205 the drive wheels 15 and 16 and motors 26 are mounted as a sub- assembly to a circular plate, or turntable, rotatably mounted under the respective raised end portion 34 or 35 of each arm.

The turntables can be rotated by a DC electric motor under the control of the microprocessor units 37,38.

The holder 10 is also provided with a sound alarm to indicate when the handler is in use and lights for operation of the handler in the dark.

With reference now to Fig 13, there is shown an aircraft handler 210 which is substantially similar to the previously described handler 10 excepting for the lifting apparatus 220.

The lifting apparatus 220 is formed as a sub-assembly which is mounted between the two opposed stub axles 52 on the chassis arms 12 & 13.

With reference to Figs 10-13, the lifting apparatus comprises a bar 221 having flattened end portions 222 which are engagable in the slots 73 in the stub axles 52 for rotational movement around the horizontal axis.

As previously described, the lifting tools are mounted by flanges 102 to the distal ends of respective lifting arms 51, each comprising two struts 61, 62. The two struts 61,62 are located in slots 223 formed in the respective end portions of an elongate support strut 224. The two struts 61,62 are held rotationally fast in one axis of rotation by the sides of the slot 223 and are pivoted to the support strut in the other orthogonal axis by pins 225,226 which are normal to the slot 223. The pivot pins 225,226 are substantially parallel to the pins 65,66 and the respective end portion of the support strut 224, struts 61,62 and lifting tool 100 form a parallelogram four bar linkage which in use holds the lifting tools 100 substantially in the same plane as the support strut.

A pair of hydraulic actuators 267 are operable between an anchor 269 and a respective outer strut 62 of each lifting arm 51. The hydraulic actuators 267 are connected by hydraulic hoses (not shown) to the control valves 43 which are in turn operated through the microprocessors 37,39 as previously described and the hydraulic pressure acting in the two actuators 267 should be equalised by suitable means.

The support strut 224 is pivotally mounted at a mid-point to a pin 227 fixed to the bar 221 also at a mid point location. The strut 224 is held on the pin 227 by a plate 228 secured to the end of the pin 227 and on which the anchor 269 is mounted.

The support strut 224 is capable of limited rotation around the pin 227, typically 7. 5 ° in each direction of rotation.

The rotation is limited flanges 231 on the bar 221 inter- engaging between pairs of flanges 232,233 on the support strut 224. Pairs of opposed springs 234 are located between flange 231 and the flanges 232,233 in order to resiliently bias the support strut into a neutral horizontal condition.

The rotation of the strut 224 around the bar 221 allows the handler to both lift and put down nose wheels where the orientation of the axle is not horizontal when the wheel is standing on the ground.