GB2226006A - Mobile platform lift - Google Patents

Abstract

The lift is for lifting an object such as a vehicle and is movable in any direction together with the lifted object. The assembly has a gantry means (1) Fig 7, including a pair of spaced apart upstanding leg portions (3) between which an object (4) to be lifted can be located. The leg portions (3) have triangular supports with wheels (5) at their lower ends. Upper ends of the leg portions (3) are interconnected by a cross-member portion (6). Cradle means are provided having two side portions (8) mounted for guided up and down substantially vertical movement one on each leg portion (3) with an object (4) to be lifted being slung between the two side portions (8) on at least two removable primary bearer beams (1) with friction support blocks 37 locatable beneath the object (4). Safety stop 20, Fig 10, is provided for the cradle. <IMAGE>

Description

A CRANE ASSEMBLY This invention relates to a crane assembly suitable particularly, but not exclusively, for lifting a vehicle or a vehicle body.

In order to put a vehicle or vehicle body (which may be of monocoque construction or may have a separate chassis) on a jig for frame or body alignment checks or realignment e.g. following accident damage, it is conventional to successively jack up each end of the vehicle and lower the respective ends onto axle stands. The jig, which normally comprises a heavy steel bed on castors, is then wheeled into position under the raised vehicle or vehicle body. However, the maximum safe height of axle stands means that the clamps which extend outwardly and upwardly from the sides of the jig bed to grip the vehicle at intervals along the sill area, and measuring posts which extend upwardly from the bed itself, may well have to be mounted on the jig bed after it is in position beneath the vehicle or vehicle body and this is of course inconvenient and time-consuming.Furthermore, lifting each end of the vehicle from its axle stands and carefully lowering it onto the jig is also a time-consuming and difficult operation bearing in mind the need for careful alignment. Alternatively crane or hoist assemblies are known which are suitable for lifting vehicles but such known assemblies are difficult to use safely when it is necessary to put a vehicle or a vehicle body on a jig for frame or body alignment checks or realignment.

Customarily this is done by lifting the vehicle or vehicle body on the end of a chain or sling and pushing the jig underneath the lifted vehicle or vehicle body. This is not satisfactory as it takes considerable time and effort to locate the jig properly underneath the vehicle and to ensure that the vehicle or vehicle body is correctly deposited thereon particularly as the slung vehicle or vehicle body can swing or twist whilst in the lifted position and must be steadied before it is lowered on to the jig. As such steadying is usually carried out manually this introduces an extra safety hazard to the operator quite apart from increasing the difficulty of accurately locating the vehicle or vehicle body on the jig. Similar hazards are also involved when unloading the vehicle or vehicle body from the jig.

A conventional four post hoist cannot be used because the longitudinal channels for the road wheels would interfere with the jig. A conventional two post hoist can be used but the lifting arms typically foul the jig necessitating the use of axle stands often leaving the vehicle in an unstable and therefore unsafe state. A conventional single post hoist cannot be used as the central post would not allow the jig to be placed below the vehicle.

There is accordingly a need for a crane or hoist which lifts the vehicle or vehicle body from underneath at two or more longitudinal locations in a simple stable manner while at the same time not interfering with the clamps on the jig. It is also highly desirable that the crane is safely movable in any desired direction even with a vehicle or vehicle body loaded thereon. This facilitates moving the vehicle or vehicle body from a storage location to a working location and also facilitates its alignment with the jig.

CB Patent Specification 1,125,083 describes a cradle-type lifting apparatus for motor vehicles comprising an overhead gantry supported by four vertical posts, two posts on each side making up a side frame and each post being provided at its lower end with a wheel permitting the lifting apparatus to be moved along the ground. However, it is clear that there is no intention of moving the apparatus while loaded as the apparatus is immobilised with jacking pads while in use. Furthermore the two-post side frames would interfere with a jig placed below the vehicle.

Each side frame has its own hydraulic piston-cylinder assembly for raising and lowering cradle frames slidable up and down the side frames and carrying removable members extend beneath the vehicle between the cradle frames. There is thus no suggestion that a vehicle or vehicle body can be lifted, and safely held for transportation, by an assembly having effectively only one post on each side of the vehicle and having removable transverse cradle members which extend beneath the vehicle or vehicle body at a spacing which does not interfere with operation of a conventional jig onto which the vehicle or vehicle body is to be lowered.

According to the present invention there is provided a crane assembly for lifting an object, including gantry means having a pair of spaced apart upstanding leg portions which are interconnected at their upper ends by a transverse cross-member portion, and between which an object to be lifted can be located, which leg portions have carrier means at their lower ends which extend forwardly and rearwardly of the respective leg portion to provide stability against forward and backward tipping particularly when the crane assembly is loaded, the carrier means having wheel means for engaging the ground or like support surface and for permitting the loaded crane assembly to be moved, cradle means having two side portions mounted for guided up and down substantially vertical movement one on each leg portion with an object to be lifted being slung between the two side portions on at least two bearer beams locatable beneath the object and removably engagable at their ends on the two side portions to extend therebetween, and means for raising and lowering the cradle means side portions, and thus an object when slung therebetween, up and down the leg portions, with the guided mounting of the cradle means side portions on the two leg portions being such as substantially to prevent swinging (about a horizontal axis) or twisting (about a vertical axis) of the side portions, and hence of an object when slung therebetween, relative to the leg portions.

This means that the object such as a vehicle or vehicle body can be lifted up on the crane assembly and the whole crane assembly wheeled over a jig and the vehicle or vehicle body deposited on the jig. This considerably improves the ease and accuracy with which a vehicle or vehicle body may be located on a jig safely without the vehicle or vehicle body swinging or twisting relative to the assembly. Furthermore the jig can be fitted witt clamps and measuring posts in advance and before access is hindered by the vehicle or vehicle body.

Advantageously the leg portions extend substantially perpendicularly from the cross-member portion and each has a reinforcing structure connecting it to a carrier means. Desirably, the reinforcing structure permits removal and replacement of the bearer beams therethrough at various cradle heights.

Generally, the wheel means permit movement of the loaded crane assembly in substantially any direction and at least one of the wheel means is provided with a brake.

Conveniently the lower ends of each leg portion are each reinforced by a substantially equilateral triangular reinforcing structure which provides the carrier means and whose base substantially centrally supports the respective leg portion end and whose apex is connected to the respective leg portion part way along the leg portion length, with the two reinforcing structures extending substantially in parallel to one another, substantially at right angles to the cross-member portion.

Preferably the wheel means on each carrier means are two castor assemblies located one at each end of the respective reinforcing structure base, each of which castor assemblies is lockable in any one of four, mutually at right angles, directions of running and is provided with its own independently operable wheel brake, and with the arrangement being such as to permit the crane assembly to be wheeled over an object to be lifted, to be movable with a lifted object slung therefrom and to be wheeled away from an object which has been released from the assembly.

In one arrangement, the assembly includes two secondary bearer beams for releasable engagement at each end on and with the two spaced primary bearer beams to extend therebetween at a suitable spacing apart corresponding to the distance apart of the lifting points of an object to be Sifted, so that the object being lifted sits on said secondary bearer beams.

In another arrangement, blocks with a channel on their lower side and with a resilient pad with an upper frictional surface on their upper side fit over the primary bearer beams.

Conveniently the base of each substantially equilateral triangular reinforcing structure and its apex provide end limits for the up and down vertical movement of the cradle means side portions.

In one embodiment the cradle means includes a crossbar portion which interconnects the upper ends of the two side portions and which extend substantially at right angles thereto, said crossbar portion and side portions being dimensioned to fit between the leg portions and under the cross-member portion. Each cradle means side portion may be a framework in the shape of a substantially equilateral triangle with each framework being connected at its apex to respective ends of the crossbar portion and with the two primary bearer beams being removably engagable with a bar forming the base of the respective triangular framework.

Conveniently each cradle means side portion is mounted for said guided up and down vertical movement on the associated leg portion, by means of two loop members projecting laterally from the side portion framework one at or adjacent the apex thereof and the other at or adjacent the base thereof, with the part of the associated leg portion lying between the base and apex of its reinforcing structures extending through the two loop members so that the base and apex of the leg portion reinforcing structure act as stops limiting the extent of vertical movement of the cradle means relative to the leg portions, and with the loop members and leg portion being formed and dimensioned to co-operate to prevent swinging or twisting of the side portions relative to the leg portions.

Conveniently the leg portions are in the form of closed box sections having a substantially rectangular cross section and wherein each loop member has a corresponding substantially rectangular aperture therethrough dimensioned to conform closely to said leg portion cross section.

Preferably the means for raising and lowering the cradle means side portions includes a motor driven winch and pulley unit mounted on the gantry means cross-member portion intermediate its ends, a pulley system mounted on the cradle means crossbar portion and a cable or chain extending between said winch and pulley unit and said pulley system.

Advantageously the drive motor for the winch is an electric motor having a source of electrical power either mounted on the gantry means or separate therefrom.

According to a first alternative embodiment of the invention each leg portion is a box section which is slotted at one side so that the slotted sides of the two leg portions face one another and each leg portion box section houses a screw threaded rod member which extends therein in the direction of the longitudinal axis thereof from a bearing block adjacent the base of the leg portion to a bearing block adjacent the cross-member portion.

Advantageously each cradle means side portion is a framework in the shape of a substantially equilateral triangle, with the two primary bearer beams being removably engagable with a bar forming the base of the respective substantially triangular framework.

Conveniently each cradle means side portion is mounted for said guided up and down vertical movement on the associated leg portion, by means of two nut members housed at least partially in the respective leg porte box section and screw threadably engaged on the screw threaded rod member for movement up and down relative to the leg portion on rotation of the rod member in one direction or the other, each said nut member having a nose part projecting through the leg portion slot and said nut members being connected by said nose parts to the side portion to project laterally therefrom one at or adjacent the apex of the framework and the other at or adjacent the base thereof, the two nut members engaging the inner surfaces of the leg portion box section via bearing means to prevent swinging or twisting of the side portions relative to the leg portions.

Preferably the bearing means on each nut member are four thrust bearings located one at or adjacent each corner of the substantially rectangular nut member.

Advantageously the means for raising and lowering the cradle means side portions includes a motor and pulley unit mounted on the gantry means cross-member portion intermediate its ends, and a chain and sprocket system mounted on the cross-member portion so that chain runs extend there along and around sprockets mounted one on each rod member, the chain runs being carried substantially at the centre of the crossmember portion on sprockets drivingly connected to the motor and pulley unit so that motion imparted thereto by the motor is transmitted via the pulleys, sprockets and chain to the rod members to rotate the latter.

Preferably the drive motor for the motor and pulley unit is an electric motor.

In a second alternative embodiment each cradle means side portion comprises a substantially vertical beam with vertically spaced members running in a guide channel on the respective leg portion and a substantially horizontal beam substantially symmetrically secured to the lower end of the substantially vertical beam and arranged to carry bearer beams, the ends of which hook thereover or are releasably connected thereto by any other suitable means.

Preferably the gantry means carries a hydraulic piston-cylinder assembly and control means therefor, the arrangement being such that extension or retraction of the piston cylinder assembly serves to raise the cradle means side portions in 'unison by way of a system of cables or chains and pulleys or sprockets.

It is also preferred that there is a movable safety catch carried by each leg portion and engageable with the respective cradle means side portion to hold it at an upper- position, that the upper end of each substantially vertical beam has means for carrying a bearer beam and that each substantially horizontal beam has a pair of stops such that a pair of bearer beams placed between the substantially horizontal beams and resting thereon are held at a spacing such that a motor vehicle wheel can be lodged between them. Less conveniently the safety catch may be on the cradle means side portion and engage a stop on the leg portion.

The invention also extends to a method of mounting a vehicle or vehicle body on a jig using the crane assembly described and a method of transporting a vehicle or other object using the crane assembly described.

For example, the invention provides a method of mounting a vehicle or vehicle body on a jig comprising positioning the crane assembly in a position to straddle the vehicle or vehicle body, placing the bearer beams in position beneath the vehicle or vehicle body such that the vehicle or vehicle body is stably balanced thereon, raising the bearer beams and the vehicle or vehicle body, moving the vehicle or vehicle body over the jig or moving the jig beneath the vehicle or vehicle body, lowering the vehicle or vehicle-body onto the jig and removing the bearer beams.

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a perspective view of an exploded gantry means part of a crane assembly according to a first embodiment of the invention, Figure 2 is an exploded perspective view of a cradle means for the crane assembly of Figure 1, Figure 3 is a perspective view of an assembled crane assembly according to the embodiment of Figures 1 and 2 shown in operative association with a vehicle in a raised or lowered position, Figure 4 is a perspective, partially broken away, view of part of a crane assembly according to a second embodiment of the invention, Figure 5 is a partially sectioned view from above taken on the line A-A of Figure 4, but reversed for convenience, Figure 6 is a perspective view of a cradle means side portion for use in the crane assembly of Figures 4 and 5.

Figure 7 is a perspective view of a crane assembly according to a third embodiment of the invention, Figure 8 is an end view of the crane assembly of Figure 7, Figure 9 is a side view of the crane assembly of Figure 8, Figure 10 is a detail view of a safety catch, Figure 11 is a diagrammatic perspective view of the crane about to lower a motor car onto a jig, and Figure 12 is a front end view of a crane showing the motor car of Figure 11 lowered onto the jig.

A crane assembly of the invention is intended for lifting an object, such as a vehicle or vehicle body, for enabling the vehicle or vehicle body to be placed on an alignment or realignment jig. Figures 1 to 3 of the accompanying drawings show a crane assembly according to a first embodiment of the invention including gantry means generally referenced 1 and cradle means generally referenced 2. The gantry means 1 has a pair of spaced apart upstanding leg portions 3 between which an object such as a vehicle 4 to be lifted can be located. The leg portions 3 are made of any convenient material and preferably are hollow steel box sections made, for example, from Grade 43 steel.

These leg portions 3 have wheel means at their lower ends for engaging the ground or like support surface. Conveniently the wheel means on each leg portion 3 are two castor assemblies 5 each of which castor assembly is lockable in any one of -four, mutually at right angles, directions of running and is provided with its own independently operable wheel brake. The crane assembly can thus be moved in substantially any direction when the castor assemblies are unlocked.

The two leg portions 3 are interconnected at their upper ends by a cross-member portion 6 made of any convenient material such as box section Grade 43 steel with reinforcing webs 6a. The leg portions 3 extend substantially perpendicularly from the cross-member- portion 6 and as illustrated in Figure 1 the lower ends of each leg portion 3 are each reinforced by a substantially equilateral triangular reinforcing structure 7. The base 7a of each structure 7 provides a carrier means which extends forward and rearwardly of the respective leg portion to provide stability against forward and backward tipping, particularly when the crane is loaded (see Figure 4). The base 7a substantially centrally supports the respective leg portion 3 and the apex 7b is connected to the respective leg portion 3 part way along the leg portion length.The two reinforcing structures 7 extend substantially in parallel to one another substantially at right angles to the cross-member portion 6.

The cradle means 2 has two side portions 8 and a crossbar portion 9 which interconnects the upper ends of the two side portions 8 and which extends substantially at right angles thereto. The crossbar portion 9 and side portions 8 are dimensioned to fit between the leg portions 3 and under the cross-member portion 6.

The side portions 8 and crossbar portion 9 can be made of any suitable material such as steel preferably made up of box sections of Grade 43 steel. As illustrated in Figure 2 each side portion 8 is a framework in the shape of a substantially equilateral triangle with each framework being connected at its apex 8a to respective ends of the crossbar portions 9. The two side portions 8 are mounted for guided up and down substantially vertical movement one on each leg portion 3. In this embodiment this is done by means of two loop members 10 which project laterally from the side portion framework one at or adjacent the apex 8a thereof and the other at or adjacent the base 8b thereof and which encircle each leg portion 3.The part of the associated leg portion 3 lying between the base 7a and apex 7b of its reinforcing structure 7 extends through the associated loop member 10 so that the base 7a and apex 7b of the leg portion reinforcing structure 7 act as stops limiting the extent of vertical movement of the cradle means 2 relative to the leg portions 3. The loop members 10 and leg portion 3 are dimensioned and formed to co-operate to prevent swinging or twisting of the side portions 8 relative to the leg portions 3. To this end the leg portions 3 are in the form of closed box sections having a substantially rectangular cross section and each loop member 10 has a corresponding substantially rectangular aperture 10a therethrough dimensioned to conform closely to the leg portion cross section.

To enable an object to be lifted to be slung between the two side portions 8 of the cradle means 2 at least two primary bearer beams 11 are pry ed; These two primary bearer beams 11 are preferably box sections made of Grade 50 steel, conveniently having a safe working load of two tons each. The primary bearer beams 11 are locatable beneath the object and removably engagable at their ends on the bases 8b of the two side portions 8 to extend therebetween. The primary bearer beams 11 thus extend in spaced apart fashion substantially parallel to one another underneath a vehicle or other object to be lifted and can be inserted thereunder with the cradle means 2 resting on the ground over an object to be lifted.To this end each primary bearer beam 11 is provided at its ends with clip or hook portions 11a shaped to conform to and co-operate with the base 8b of each side portion 8 in an easily releasable manner.

Additionally two secondary bearer beams 12 are provided for releasable engagement at each end on and with the two spaced apart primary bearer beams 11 to extend therebetween at a suitable spacing apart corresponding to the distance apart of the lifting points of an object such as a vehicle to be lifted. If the object to be lifted is a vehicle the secondary bearer beams 12 act as sill supports on which the sills of the vehicle sit and to this end the secondary bearer beams 12 may be provided with end pads 12a made of any convenient high friction protective material for engagement with the vehicle sills in a non-slip and non damaging manner. Additionally the secondary bearer beams 12 may be provided at their ends with safety lips 12b for hooking over the primary bearer beams 11. The length of the secondary bearer beams 12 and thus the spacing of the bearer beams 11 is sufficient to stably mount the vehicle or vehicle body while at the same time not interfering with clamps on a jig onto which the vehicle or vehicle body is lowered, the clamps normally being outside the beams. The beams 12 may be replaced by blocks 37 as described below in connection with Figure 7.

The crane assembly of the invention also includes means for raising and lowering the cradle means side portions 8, and thus an object when slung therebetween, up and down the leg portions 3 with the guided mounting of the cradle means side portions 8 by means of the loop members 1 on the two leg portions 3 being such as substantially to prevent swinging or twisting of the side portions 8 and hence of an object when slung therebetween, relative to the leg portions 3. As can be seen from Figures 1, 2 and 3 the means for raising and lowering the cradle means side portions 8 includes a motor driven winch and pulley unit 13 having a motor 13a, a pair of winches 13b driven through reduction gearing (not shown) and pulley 13c.The unit 13 is mounted on the gantry means cross-member portion 6 intermediate the ends of the portions 6.

The cradle means cross bar portion 9 has a pair of pulleys 14 mounted thereon and a cable or chain 15 extends between the winches 13b leaving one winch 13b, passing downwards around one pulley 14 and upwards over pulley 13c, then downwards again around the other pulley 14 and back to the other winch 13b, the pulley 13c serving to balance the proportion of the load carried by the two winches 13b. The arrangement can be more easily seen from Figure 3. To accommodate the pulley system 14 more easily the crossbar portion 9 of the cradle means 2 is made conveniently of two spaced apart U-section channels as illustrated in Figure 2, with the pulley system 14 mounted therebetween.The drive motor 13a for the winch or winches 13b preferably is an electric motor having a source of electrical power either mounted on the gantry means such as by means of the illustrated battery 16 or separately therefrom e.g. a mains supply.

The battery 16 may be provided with a cover 17 and an optional battery charger 18. Additionally the winch and pulley unit 13 may be fitted with a safety overload device to cut out in the event that the assembly is asked to lift a load greater than its planned capacity, which preferably is a safe working load of two tons. If desired the winch and pulley unit 13 may be controlled by remote radio control module or a conventional wandering lead. Alternatively a pneumatic power supply can be used.

As shown in Figure 3 the crane assembly of the invention allows a vehicle to be lifted and the whole assembly and vehicle moved by means of the castor assemblies 5 over a body jig without any twisting or tilting or swinging of the vehicle 4 during such movement. The assembly can be used for Joading and unloading vehicles from body jigs of all types, for lifting vehicles for inspection and work after first placing axle stands underneath and/or operating a safety catch e.g. as shown in Figure 7, for moving badly damaged or partially dismantled vehicles, for removing bodies from chassis or even for removal of engines from vehicle. The assembly affords complete mobility and easy storage which may be over a vehicle and the assembly can be built with any convenient lifting height such as, for example, a lifting height of 1 metre.

The crane assembly according to a second embodiment of the invention as illustrated in Figures 4, 5 and 6 is basically similar to that of the first embodiment and like parts have been given like reference numerals and will not be described again in detail. The basic difference is that in the assembly in the second embodiment there is no crossbar portion on the cradle means side portions 8. Instead the leg portions 3 are each in the form of a box section which is slotted with a slot 19 at one side so that the slotted sides of the two leg portions 3 face one another as shown in Figure 4.Each leg portion box section houses a screw threaded rod member 20, of which only one has been shown for convenience, in Figure 4, which extends therein in the direction of the longitudinal axis thereof from a bearing block or assembly 21 adjacent the base of the leg portion 3 and a bearing block or assembly 22 adjacent the cross-member portion 6.

Each cradle means side portion 8 is still a framework in the shape of a substantially equilateral triangle with the two primary bearer beams 11 being removably engagable with the bar 8b forming the base of the respective substantially triangular framework. However each cradle means side portion 8 is mounted for the guided up and down vertical movement on the associated leg portion 3 by means of two nut members 23 housed at least partially in the respective leg portion box section and screw threadably engaged on the screw threaded rod member 20 for movement up and down relative to the leg portion on rotation of the rod 'member in one direction or the other. Each nut member 23 has a nose part 24 projecting through the leg portion slot 19.The nut members 23 are connected by their nose parts 24 to the side portion 8 to project laterally therefrom one at or adjacent the apex 8a of the framework and the other at or adjacent the base 8b thereof depending on how high above the ground the side portion is to be when in its lowermost position. The nut members 23 preferably are substantially rectangular in cross section so as to engage relatively closely the inside walls of the rectangular box section leg portion 3 and thereby prevent swinging or twisting nf the side portions 8 relative to the leg portions 3. Additionally the nut members 23 engage the inner surfaces of the leg portion box section via bearing means such as thrust bearings 25 rotatably mounted at each corner of the nut members 23.The thrust bearings 25 are conveniently rotatable wheels made of nylon for running on the inside surfaces of the leg portion box section.

In this embodiment the means for raising and lowering the cradle means side portions 8 includes a motor and pulley unit 26 mounted on the gantry means cross-member portion 6 intermediate its ends and a chain and sprocket system including two chain runs 27 and four sprockets 28.

The chain and sprocket system is mounted on the cross-member portion 6 also so that the chain runs 27 extend therealong and around respective sprockets 28 which are mounted one on each rod member and fixedly connected to the rod member to rotate therewith. The chain runs 27 engage at their other ends around two sprockets 28 located substantially at the centre of the cross-member portion 6 in driven connection with the motor and pulley unit 26, preferably via a belt 29 and pulley 30, so that motion imparted by the motor to the chains 27 is transmitted thereby to the rod members 20 to rotate the latter. Preferably the drive motor for the motor and pulley unit 26 is an electric motor as in the first embodiment.

Anti-scuff or safety covers may be fitted to the side portions 8 of the cradle means 2 in both embodiments of the invention. Such a cover is shown diagrammatically at 31 in Figure 5. The covers 31 may also function as safety curtains. Additionally the motor or the motor and pulley unit 26 may also be provided with a safety overload cut out.

The embodiment of Figures 7 to 10 is similar in most respects to the embodiment of Figures 4 to 6 but lifting is effected by a single pistoncylinder unit mounted in the cross-member portion of the gantry and - connected to the cradle means side portions by cables. The shape of the cradle means side portions has been changed to improve both appearance and accessibility.

A gantry means 1 comprises a cross-member portion 6 comprising an upper beam 6a and a lower beam 6b between which is mounted a drive unit 35 to be described in more detail below, and two leg portions or posts 3. Each leg portion 3 is a single hollow box section beam which facilitates access to the jig and two mutually facing L-section members are welded to the inwardly facing side of each beam to provide a vertical T-section cavity with access through a vertical slot 19. The lower end of each leg portion 3 is bolted to the centre of a carrier beam 7a which extends forwardly and rearwardly of the leg portion 3 to provide stability when the crane assembly is loaded with a vehicle and moved in the loaded condition.A pair of inclined reinforcing beams 7 extend between the respective ends of the carrier beams 7a to points on opposite sides of the leg portions 3 about halfway along their length. The beams 7 are bolted in sockets welded to the carrier beam 7a and the leg portion respectively.

At each end of each carrier beam 7a there is a castor assembly 5 of conventional type in which a bracket holding a wheel is freely rotatable about a vertical axis, the horizontal wheel axis being displaced from the vertical axis to obtain a trailing effect as the castor assembly is pushed along. Each castor assembly may be provided with a brake and means for locking it in a selected orientation in a conventional manner.

The cradle side portions 8 each comprise a vertical beam 8a welded to a .hanrizonti base means 8b and to a shorter horizontal upper beam 8c, and inclined struts Sd are welded in position between a point inwardly of the end of the base beam 8b and point about one third of the way up the vertical beam 8a. The horizontal beams 8b and 8c each have flanges 8e at their ends to locate transverse bearer beams 11 which, as previously described, have hook portions 11a at their ends which fit over the base beam 8b.However, the beams 11 can also be hooked onto the beams 8c (with a closer spacing) so that a block can be bolted to the two beams 11 midway along their length, the block being provided with a chain or the like to lift engines out of vehicles for example. It is also envisaged that a similar arrangement is used for lifting and transporting builders' skips.

The arrangement thus has considerable versatility. In this embodiment, the secondary bearer beams are replaced by blocks 37 having channels 38 on their lower sides which fit over the bearer beams 11 and are positioned to engage appropriate parts of the underside of the vehicle, the blocks 37 having the pads 12a of frictional material on their upper surface. The blocks 37 are even less likely to interfere with the jig than the secondary bearer beams 12 of the first and second embodiments.

Each vertical beam 8a has two bearing members 23 of a T-shape similar to that shown in Figure 6 (but without the central hole) which extend through the slots 19 into the cavity provided by the L-section members welded to the leg portion 3 and substantially correspond with its internal shape, with greasing providing an adequately free slide bearing.

The top bearing member 23 is at the top of the beam 8a but the bottom bearing member is above the bottom of the beam 8a to permit the beam 8a to reach the ground without the bearing member 23 abutting the carrier beam 7a.

The points of attachment of the struts 8d to the base beam 8a are such that if the bearer beams 11 are placed inside these points of attachment, the bearer beams 11 have a spacing suitable for locating and holding a vehicle wheel. With this arrangement, the front or rear end of a veherie can be lifted in the manner of a 'spectacle' lift to facilitate inspection an our repair.

The drive unit 35 comprises an electric (or pneumatic) motor 40 which drives a hydraulic pump 42 in a conventional manner. The hydraulic pump 42 is connected through a conventional valve to a horizontal pistoncylinder assembly 44, the piston rod 46 of which drives a vertical plate 48 along rails 50 secured to the mutual facing sides of beams 6a, 6b, the plate 48 having notched bearing surfaces which fit over the rails. Secured to the lower portion of the plate 48 are a first pair of wire cables 52 which extend along respective sides of the beam 6b over pulleys 54 and downwardly to one cradle side portion 8.Secured to the upper portion of the plate 48 are a second pair of cables 62 which extend along the respective sides of beam 6a in the same direction as cables 52 but are reversed around pulleys 64 on beams 6a and pass around pulleys 66 before descending to the other cradle side portion 8. In practice guards 67 are placed over the pulleys to prevent the cables coming off if they become slack for any reason. This arrangement provides a simple, efficient and inexpensive means of raising and lowering the cradle which employs a single piston-cylinder assembly 44 mounted where it does not obscure access and where it is not prone to damage in a crowded workshop.

Preferably the motor 40 is only switched on for the raising operation, the lowering operation being effected by bleeding hydraulic fluid in the piston-cylinder assembly back to the fluid reservoir (not shown).

Desirably the bleeding can be effected at two or more speeds by control valves so that the vehicle can be lowered more slowly as it approaches the ground or the jig.

For safety reasons a catch 70 is provided on each leg portion 3 and is shown in detail in Figure 10. This comprises a plate 72 of suitable end profile for engaging the underside of struts Bd (or of base 8b) and pivotably mounted about a horizontal axis 74 on the leg portion for movement between an operative position below the particular part of the side portion 8 and an inoperative position which is clear of the side portion 8 s 85 welded to the leg portion provide stops for limiting the mevernent of the plate 72, the plate 72 being held against the lugs 85 in both the operative position and the inoperative position by the force of gravity.The plate 72 shown is conveniently connected via a rotary shaft on axis 74 to a similar plate on the other side of the same leg portion 3 to provide additional security.

For safety reasons, each carrier beam 7a is normally at least about 180 cm long but this length does not interfere with the operation of the crane assembly. On the other hand the length of the beams 8b is preferably about 106 cm, with the bearer beams 11 being about 210 cm long.

Another advantage of the crane assembly is that once the vehicle is clamped to the jig, the vehicle and the jig can be lifted together and moved to another part of the workshop, the beams 11 passing beneath the jig.

Referring now to Figures 11 and 12, the jig 90 is shown diagrammatically as it is of conventional form. It comprises a heavy rectangular bed 92 mounted on four castors 94 adjacent the four corners.

Two screw clamps 96 (omitted from Figure 12 for simplicity) are mounted on respective spaced brackets 98 which extend upwardly and outwardly from each side of the bed 92. These clamps 96 each have a pair of clamp plates 102 which can be moved along the brackets 98 so as to form a movable vice for clamping the sill of the car 4. Measuring posts 104 are also provided on the bed 92 but can be pivoted from their operative vertical position into a horizontal storage position. In operation, the car 4 which is carried by the beams 11 is lowered onto the jig 90, the crane assembly and the jig 90 being moved relative to each other to achieve the required alignment.The single post 3 and the triangular reinforcing arrangement 7 provide good accessibility to the car 4 and the clamps 96 and permit easy removal of the beams 11 and blocks 37 when the car 4 rests on the clamps 96, and the beams 11 do not interfere with the clamps 31 cL?iflq the lowering operation. The car 4 can be lifted from the jig after repair by sliding beams 11 and blocks 37 in position beneath it. An alternative conventional jig (not illustrated) with which the crane may be used has tailormade brackets that bolt onto the jig and onto various locations on the vehicle such as suspension points, engine mounts etc.

The three embodiments specifically described could be modified so that the cradle is raised and lowered by hydraulic piston-cylinder assemblies mounted in the leg portions 3.

Other uses envisaged for the crane assembly include interchanging lorry bodies e.g. from a container body to a flat-top body and loading and unloading boats from lorries or trailers using slings and moving them around shipyards or other boat-storage and boat-maintenance areas.

It is also envisaged that the wheels could be fully controllable as to direction by an operator and could be driven e.g. by a hydraulic or electric motor. As mentioned above, the crane assembly can be totally battery powered to make it independent of electric or pneumatic connections to mains systems. Certain terrains will necessitate pneumatic tyres on the wheels.

The following safety features will in practice be incorporated in all three embodiments: - safety catches operable in two positions - use of four cables - full electrical insulation - key operable handset to immobilise lowering of hoist - directional and rotational brakes on all wheels - side frames stop 5 cm from ground to prevent toes being trapped - 5 cm gap between side and main frames to avoid hands being trapped - nature and location of the bearings meaning fingers cannot be trapped - flow valve on hydraulics to limit drop to 0.1 metre/second in event of hydraulic failure - microswitch on lower crossbar to avoid roof damage to tall vehicles - cuts off electrical supply - guards over all pulleys to locate cables if they become slack.

Claims (33)

1. A crane assembly for lifting an object, including gantry means having a pair of spaced apart upstanding leg portions which are interconnected at their upper ends by a transverse cross-member portion, and between which an object to be lifted can be located, which leg portions have carrier means at their lower ends which extend forwardly and rearwardly of the respective leg portion to provide stability against forward and backward tipping particularly when the crane assembly is loaded, the carrier means having wheel means for engaging the ground or like support surface and for permitting the loaded crane assembly to be moved, cradle means having two side portions mounted for guided up and down substantially vertical movement one on each leg portion with an object to be lifted being slung between the two side portions on at least two bearer beams locatable beneath the object and removably engagable at their ends on the two side portions to extend therebetween, and means for raising and lowering the cradle means side portions, and thus an object when slung therebetween, up and down the leg portions, with the guided mounting of the cradle means side portions on the two leg portions being such as substantially to prevent swinging or twisting of the side portions, and hence of an object when slung therebetween, relative to the leg portions.

2. An assembly according to Claim 1, wherein the wheel means permit movement of the loaded crane assembly in substantially any direction.

3. An assembly according to Claim 1 or 2, wherein at least one of the wheel means is provided with a brake.

4. An assembly according to any preceding claim, wherein the leg portions extend substantially perpendicularly from the cross-member portion and each has a reinforcing structure connecting it to a carrier means

5. An assembly according to Claim 4, wherein the reinforcing structure permits removal and replacement of the bearer beams therethrough at various cradle heights.

6. An assembly according to Claim 4 or 5, wherein the lower ends of each leg portion are each reinforced by a substantially equilateral triangular reinforcing structure whose base substantially centrally supports the respective leg portion end and provides the carrier means and whose apex is connected to the respective leg portion part way along the leg portion length, with the two reinforcing structures extending substantially in parallel to one another substantially at right angles to the cross-member portion.

7. An assembly according to Claim 6, wherein the wheel means on the carrier means are two castor assemblies located one at each end of the respective reinforcing structure base, each of which castor assemblies is lockable in any one of four, mutually at right angles, directions of running and is provided with its own independently operable wheel brake, and with the arrangement being such as to permit the crane assembly to be wheeled over an object to be lifted, to be movable with a lifted object slung therefrom and to be wheeled away from an object which has been released from the assembly.

8. An assembly according to any preceding claim, including two secondary bearer beams for releasable engagement at each end on and with the two spaced apart primary bearer beams to extend therebetween at a suitable spacing apart corresponding to the distance apart of the lifting points of an object to be lifted, so that the object being lifted sits on said secondary bearer beams.

9. An assembly according to any one of Claims 1 to 7, including blocks with anti friction material thereon, such blocks having an inverted channel fitting over the primary bearer beams and arranged to engage bearing points of the object being lifted.

10. An assembly according to any one of Claims 4 to 7, wherein the base of each substantially equilateral triangular reinforcing structure and its apex provide end limits for the up and down vertical movement of the cradle means side portions.

11. An assembly according to any one of Claims 4 to 7, wherein the cradle means includes a crossbar portion which interconnects the upper ends of the two side portions and which extend substantially at right angles thereto, said crossbar portion and side portions being dimensioned to fit between the leg portions and under the cross-member portion.

12. An assembly according to Claim 11, wherein each cradle means side portion is a framework in the shape of a substantially equilateral triangle with each framework being connected at its apex to respective ends of the crossbar portion and with the two primary bearer beams being removably engagable with a bar forming the base of the respective triangular framework.

13. An assembly according to Claim 12, wherein each cradle means side portion is mounted for said guided up and down vertical movement on the associated leg portion, by means of two loop members projecting laterally from the side portion framework one at or adjacent the apex thereof and the other at or adjacent the base thereof, with the part of the associated leg portion lying between the base and apex of its reinforcing structure extending through the associated loop members so that the base and apex of the leg portion reinforcing structure act as stops limiting the extent of vertical movement of the cradle means relative to the leg portions, and with the loop members and leg portion being formed and dimensioned to co-operate to prevent swinging or twisting of the side portions relative to the leg portions.

14 An assembly according to Claim 13, wherein the leg portions are in t rm of dosed box sections having a substantially rectangular cross section and wherein each loop member has a corresponding substantially rectangular aperture therethrough dimensioned to conform closely to said leg portion cross section.

15. An assembly according to Claim 13 or 14, wherein the means for raising and lowering the cradle means side portions includes a motor driven winch and pulley unit mounted on the gantry means cross-member portion intermediate its ends, a pulley system mounted on the cradle means crossbar portion and a cable or chain extending between said winch and pulley unit and said pulley system.

16. An assembly according to Claim 15, wherein the drive motor for the winch is an electric motor having a source of electrical power either mounted on the gantry means or separate therefrom.

17. An assembly according to any one of Claims 4 to 7, wherein each leg portion is a box section which is slotted at one side so that the slotted sides of the two leg portions face one another, and wherein each leg portion box section houses a screw threaded rod member which extends therein in the direction of the longitudinal axis thereof from a bearing block adjacent the base of the leg portion to a bearing block adjacent the cross-member portion.

18. An assembly according to Claim 17, wherein each cradle means side portion is a framework in the shape of a substantially equilateral triangle, with the two primary bearer beams being removably engagable with a bar forming the base of the respective substantially triangular framework.

19. An assembly according to Claim 18, wherein each cradle means side portion is mounted for said guided up and down vertical movement on the associated leg portion, by means of two nut members housed at least partially in the respective leg portion box section and screw threadably engaged in the screw threaded rod member for movement up and down relative to the leg portion on rotation of the rod member in one direction or the other, each said nut member having a nose part projecting through the leg portion slot and said nut members being connected by said nose parts to the side portion to project laterally therefrom one at or adjacent the apex of the framework and the other at or adjacent the base thereof, the two nut members engaging the inner surfaces of the leg portion box section via bearing means to prevent swinging or twisting of the side portion relative to the leg portion.

20. An assembly according to Claim 19, wherein the bearing means on each nut member are four thrust bearings located one at or adjacent each corner of the substantially rectangular nut member.

21. An assembly according to Claim 19 or 20, wherein the means for raising and lowering the cradle means side portions includes a motor and pulley unit mounted on the gantry means cross-member portion intermediate its ends, and a chain and sprocket system mounted on the cross-member portion so that chain runs extend therealong and around sprockets mounted one on each rod member, the chain runs being carried substantially at the centre of the cross-member portion on sprockets drivingly connected to the motor and pulley unit so that motion imparted thereto by the motor is transmitted by the pulleys, sprockets and chain to the rod members to rotate the latter.

22. An assembly according to Claim 21, wherein the drive motor for the motor and pulley unit is an electric motor.

23. An assembly according to any one of Claims 1 to 8, wherein each cradle means side portion comprises a substantially vertical beam with vertically spaced or continuous members running in a guide channel on the respective leg portion and a substantially horizontal beam substantially symmetricafly secured to the lower end of the substantially vertical beam and arranged to carry the bearer beams, the ends of which hook thereover.

24. An assembly according to Claim 23, wherein the gantry means carries a hydraulic piston-cylinder assembly and control means therefor, the arrangement being such that extension or retraction of the pistoncylinder assembly serves to raise the cradle means side portions in unison by way of a system of cables or chains and pulleys or sprockets.

25. An assembly according to Claim 24, wherein the control means include a motor driven hydraulic pump, a hydraulic fluid reservoir and a control valve means for controlling flow of fluid between the pump, the piston-cylinder assembly and the reservoir.

26. An assembly according to Claim 23, 24 or 25, wherein there is a movable safety catch carried by each leg portion and engageable with the respective cradle means side portion to hold it at an upper position.

27. An assembly according to any one of Claims 23 to 26, wherein the upper end of each substantially vertical beam has means for carrying a bearer beam.

28. An assembly according to any one of Claims 23 to 27, wherein each substantially horizontal beam has a pair of stops such that a pair of bearer beams placed between the substantially horizontal beams and resting thereon are held at a spacing such that a motor vehicle wheel can be lodged between them.

29. A crane assembly according to any preceding claim, wherein the leg portions each comprise a single post.

3D. An assembly according to any preceding claim, which is suitable for towering a vehicle or vehicle body onto a jig.

31. A crane assembly substantially as hereinbefore described and as illustrated in Figures 1 to 3, Figures 4 to 6 or Figures 7 to 10 of the accompanying drawings.

32. A method of mounting a vehicle or vehicle body on a jig comprising positioning a crane assembly according to any preceding claim in a position to straddle the vehicle or vehicle body, placing the bearer beams in position beneath the vehicle or vehicle body such that the vehicle or vehicle body is stably balanced thereon, raising the bearer beams and the vehicle or vehicle body, moving the vehicle or vehicle body over the jig or moving the jig beneath the vehicle or vehicle body, lowering the vehicle or vehicle body onto the jig and removing the bearer beams.

33. A method of transporting a vehicle or vehicle body in which there is employed a crane assembly according to any one of Claims 1 to 31.