GB2104867A

GB2104867A - Crane

Info

Publication number: GB2104867A
Application number: GB08114117A
Authority: GB
Inventors: Simon Brian Owen Knapp
Original assignee: TONNES FORCE
Current assignee: TONNES FORCE
Priority date: 1981-05-08
Filing date: 1981-05-08
Publication date: 1983-03-16
Also published as: GB2104867B

Abstract

A crane 10 for use on a helipad comprises a base 12 carrying load bearing means 14 which are selectively collapsible from and erectable into a load bearing condition. A strut 44 is arranged releasably to maintain the load bearing means 14 in the load bearing condition. Collapse of the load bearing means 14 significantly reduces the height of the crane so that a helicopter can land in its vicinity without the crane causing an obstruction. To collapse the crane 10 rams 32 are retracted to bring load bearing arm 28 parallel to and adjacent support beam 26 when projections 50, 52 can be pinned together to fix the arm 28 to the beam 26, release of the strut 44 from attachment plate 48 then enables the rams 32 to be extended to swing the beam 26 and arm 28 down about pivot 42 parallel to chains 16 where the strut 44 can be attached to a further attachment plate 54. The strut 44 may alternatively be attached at a plate 56 in an erected position giving further outreach. <IMAGE>

Description

SPECIFICATION Crane This invention concerns cranes and particularly, although not solely, cranes for use on helipads.

It is well known that in order to avoid obstructing a helicoper when it is landing on a helipad, the helipad must be cleared of all objects which have a height greater than two feet. This means that no unloading machinery is immediately ready to hand once the helicopter has landed because unloading cranes and iifting trucks are generally at least six feet in height. For this reason, it is customary either to delay unloading until a crane or truck has been brought onto the pad or to unload the helicopter manually.

Either way, time delays occur. and, in the latter case, there is risk of injury to persons manually unloading heavy items, and of damage to goods, equipment and aircraft.

One aim of the present invention, therefore, is to overcome such problems by providing a crane which need not be removed from a helipad whilst a helicopter is landing.

A further aim is to provide an unloading method which avoids the delays previously existing.

And another aim of the invention, at least in its preferred form, is to provide a crane which is simple in construction and versatile in use. In particular, the preferred embodiment described below is a dual purpose crane capable of use both in a helipad environment and for loading and unloading bulk containers.

According to one aspect of the invention, a crane comprises a base, load bearing means mounted on the base, the load bearing means being selectively collapsible from and erectable into a load bearing condition, and retention means arranged releasably to maintain the load bearing means in a load bearing condition.

Because the load bearing means are selectively collapsible, the overall height of the crane can be reduced whenever necessary, for example during a helicopter landing. As soon as landing is complete, the load bearing means are re-erected and the crane is instantly in a condition to unload the helicopter.

In a preferred form of the invention, collapse and erection of the load bearing means are effected by an operating ram which serves also to operate a load bearing arm of the crane in use. A particularly simple construction for the crane is thus possible. For example, the load bearing means may comprise a support beam pivoted to the base for rotation between a collapsed condition and the load bearing condition, and a load bearing arm pivoted to the support beam, and the operating ram may be arranged to act between the base and the load bearing arm such that normally it controls the operation of the load bearing arm as required. However, by securing the arm relative to the support beam, the operating ram moves the arm and support beam in unison for collapsing and subsequently re-erecting the load bearing means.

A further significant feature ofthe present invention is that the load bearing means is selectively adjustable between a plurality of load bearing conditions. For this purpose, the preferred embodiment is constructed so that the support beam can be pivotably retained in a variety of angular positions relative to the base, adjustment of its position again being controlled by the operating ram. The retention means may be adapted to maintain the load bearing means in any one of the load bearing conditions, or they may be replaced by aiternative retention means when the load bearing means are adjusted from one load bearing condition to another.

This facility for adjusting the crane to suit different operating conditions has various advantages. Firstly, by adjusting the support beam from a more upright to a more inclined position, the overall height of the crane can be reduced from a height suitable to enable the arm to reach in through the door of a helicopter to a height permitting the crane to enter a confined space, such as a standard sized bulk container, for loading and unloading purposes. And secondly, the load bearing means can be arranged so that their reach relative to a portion of the base may be varied by altering their condition to facilitate certain lifting operations.For example, in unloading a helicopter, the crane can be set into one load bearing condition at the beginning of the unloading operation when the goods to be unloaded are readily accessible through the door of the helicopter, and into another unloading condition in which the maximum reach of the load bearing means relative to a portion of the base is increased, for better penetration into the helicopter towards the end of the operation when the goods are further removed from the door.

Preferably, for additional versatility, the crane is also provided with a base whose dimensions are adjustable. This again may serve to increase the maximum reach of the crane relative to a portion of the base. Also, it is particularly advantageous if the width of the base can be adjusted. The crane can then be made compact for transport purposes and for application in loading or unloading a bulk container and the base can be spread in use of the crane on a helipad for greater stability. One type of base construction for achieving this features a generally U-shaped support frame whose limbs are interconnected by a bridge portion which is selectively collapsible for adjustment of the spacing between the limbs.

For another aspect the invention provides a method for unloading an aircraft comprising providing a crane at a landing area for the aircraft, collapsing the crane during landing of the aircraft, re-erecting the crane when the aircraft is landed, and unloading the aircraft.

The invention is described further, by way of example, with reference to the accompanying drawings in which: Figure 1 is a side view of the crane in its operating condition; Figure 2 is a side view of the crane showing it both in a partially collapsed and in its collapsed condition; and Figure 3 is a plan view of the base of the crane.

Shown in the drawings is a crane 10 having a base 12 and a load bearing means 14 mounted on the base 12. The base 12 is mobile and comprises a generally U-shaped chassis 1 6 whose bridge portion 18 is arranged at the front of the crane and is supported on a pair of front wheels 20 and whose two limbs 22 are supported at their free ends by a respective set of rear wheels 24.

The load bearing means 14 are mounted on the bridge portion 1 8 of the base 12 so as to face towards the rear of the crane 10 and comprise a normally upright support beam 26, and a load bearing arm 28 pivoted at one end to the upper end of the support beam 26. The other end of the arm 28 has a hook 30 for carrying a load. A pair of hydraulic rams 32 (only one of which is illustrated) control movement of the load bearing arm 28, the cylinder 34 of each being pivotably mounted on the chassis bridge portion 1 8 and the piston 36 being pivotably secured to the arm 28 at a location remote from the hook 30.

More particularly, the bridge portion 1 8 of the chassis 1 6 has a central platform 38 with two rearwardly extending lugs 40 which carry a pivot 42. The support beam 26 is mounted on the pivot 42 and is thus rotatable relative to the chassis 1 6.

Normally, the support beam 26 is retained in its erect, loadbearing condition by a strut 44 which is pivoted at one end to a first attachment plate 46 near the front of the platform 38 and at the other end to a second attachment plate provided near the middle of the support beam 26. However, the connection between the strut 44 and the second attachment plate is releasable to enable the beam 26 to fold down between the limbs 22 of the chassis 1 6 to reduce the overall height of the crane below 2 feet.

Such collapse of the load bearing means 14 is effected in the following manner. Firstly the load bearing arm 28 is drawn downwardly against the support beam 26 by the ram 32. This brings a projection 50 on the arm 28 near the hook 30 into line with a projection 52 on the lower end of the support beam 26, and by inserting a pin (not shown) through the two projections, the arm 28 and support beam 26 are then held in fixed relation. Once the two have been secured together, the strut 44 is detached from the support beam 26 and the rams are once again extended to some extent. Since the arm 28 is unable to pivot now relative to the beam 26, the extension of the rams 32 causes the beam 26 to turn on its pivot 42.The beam 26 gradually lowers towards the chassis 1 6 under the control of the rams 32 until the load bearing means are fully collapsed and lie substantially parallel to the chassis 1 6 between the limbs 22. At this point, the strut 44 is reattached to the beam 26 by securing its end remote from the platform 38 to a further attachment plate 54 on the beam. The load bearing means are now securely held in their collapsed condition in which as is evident from the drawings the overall height of the crane is substantially reduced.

In order to re-erect the load bearing means, the strut 44 is once again detached from the support beam 26 and the rams 32 are retracted to cause the beam 26 once more to turn on the pivot 42. This time, the result is that the beam is raised into its upright position whereupon the strut 44 can be secured once more to the attachment plate 48 and the connection between the projections 50, 52 on the arm and the beam can be released. The crane is then rendered operational by extending the rams 32 to lift the arm 28 into a substantially raised position as shown in Figure 1.

In this position, the arm 28 is spaced from the base 12 by an amount corresponding approximately to the length of the support beam 26, and the hook 30 is located generally in line verticaliy with the rear wheels 24. As a result, it is possible to extend the load bearing arm 28 into the cabin of a helicopter for unloading purposes simply by backing the chassis 1 6 under the helicopter body. The hook 30 can be extended right into the helicopter in this manner since the crane 10 can be backed towards the helicopter until the helicopter is almost adjacent to the support beam 26. Once a load has then been attached to the hook 30, rams 32 are extended so that the arm 28 and the hook 30 are raised sufficiently to lift the load from the floor of the cabin of the helicopter. The crane 10 can then be advanced away from the helicopter to remove the load.The mobility of the crane coupled with the arrangement of the arm 28 in relation to the base 1 2 are thus advantageous in facilitating unloading of a helicopter.

An even greater degree of penetration of the hook 30 into a helicopter cabin can, however, be achieved if necessary with the present crane by adjusting the upright position of the support beam 26. In the position illustrated in Figure 1, the strut 44 is attached between the plate 46 on the platform 38 and the plate 48 on the beam 26. As shown, yet another attachment plate 56 is provided on the beam 26 between the two plates 46 and 54. To adjust the inclination of the beam 26 relative to the base 12, the arm 28 is dropped against the beam 26 by retracting the rams 32 and is attached to the beam as for collapse, the strut 44 is released from the attachment plate 48, the rams 32 are extended just sufficiently to tilt the support beam 26 rearwardly by an amount which allows the strut 44 to be engaged with the plate 56 on the beam 26. When this connection has been made, the arm 28 is released from the support beam 26 and the rams 32 are once again extended to place the arm in an operational condition. Because the support beam 26 has now been tiited rearwardly, the maximum reach of the arm 28 relative to the rear wheels 24 is effectively increased and the hook 30 can be extended further into a helicopter cabin than was previously possible.

An additional and important effect of adjusting the angle of the beam 26 in relation to the base 1 2 is that the overall height of the crane is varied.

By inclining the beam 26 towards the rear wheels 24 the height of the crane is reduced for enabling the crane to enter the confined space within say a standard sized bulk container for the purpose of loading or unloading it. In this configuration, the hook 30 is offset vertically relative to the rear wheels 24 and the crane can pick up items on the floor of the container which rest in contact with these wheels.

It is a further feature of the invention, that the base 1 2 is selectively collapsible to reduce its width. For this purpose, the limbs 22 are connected to the central platform 38 by way of respective link elements 58 which permit the limbs 22 to be moved towards and away from the platform 38 as desired. Each link element 58 has a first, vertical portion 60 and a second, horizontal portion 62. The vertical portion 60 has a stub shaft 62 welded to it to provide a bearing for a pin 66 which extends between the front end of the associated limb 22 and a support 68 secured to the limb. The free end of the horizontal portion 62 is likewise pivoted to the central platform 38.

Thus, by pivoting each limb 22 relative to the associated link element 58 and each link element 58 relative to the platform 38, the chassis 1 6 is adjustable from a spread condition, in which each limb 22 lies at right angles to the associated link element 58, to an indrawn condition (shown in dashed lines in Figure 3) in which each limb 22 is folded beside and lies parallel to the associated link element 58. The width of the base is reduced by drawing the limbs 22 together in this manner and, in addition, its length is also reduced as can be seen in Figure 3.

Thus the base of the crane can be made compact for transport purposes or if it is desired to use the crane in a location where restricted space is availabie, for example in a bulk container.

Where space permits, however, it is preferable for the limbs 22 to be arranged in the spread condition of the base 1 2 to give added stability to the crane.

An added benefit of the present construction for the crane base is that drawing in of the limbs 22 also has the effect of increasing the maximum reach of the arm 28 relative to the rear wheels 24, which may again be useful for unloading purposes.

Movement and operation of the crane are normally controlled from a power unit 70 supported on one of the link elements 58 and supplied with control signals from a location remote from the crane. The unit 70 is mounted on the respective link element 58 so that it will not interfere with the central platform 38 and the respective limb 22 when the limb is folded beside the link element. It contains a motor for supplying a drive to the front wheels 20 and a pressure unit for operating the rams 32. For safety the unit is arranged selectively to drive the wheels 20 or operate the rams 32, but not to do both at the same time.

The crane 10 is also provided with a handle 72 to allow it to be steered and positioned manually.

The described crane is intended primarily for use on a helipad. For loading and unloading purposes, it remains erected as shown in Figure 1.

However, whenever a helicopter is landing or taking off the crane is simply collapsed as shown in Figure 2. Its height is thus reduced below the two foot level so that it can remain on the helipad without obstructing the helicopter.

Of course, this is not the only application suitable for the crane and the adjustability of its base renders it suitable for use in confined spaces.

Various modifications are possible. For example, instead of using a single strut 44 with a plurality of attachment plates on the support beam 26 for retaining the load bearing means 14 in the selected condition, the beam can have a single attachment plate and a selected strut, chosen from a plurality of struts of different lengths, can be attached between this plate and the one on the central platform 38 for holding the support beam in the desired angular position.

Claims

1. A crane comprising a base, load bearing means mounted on the base, the load bearing means being selectively collapsible from and erectable into a load bearing condition, and retention means arranged releasably to maintain the load bearing means in the load bearing condition.

2. A crane as claimed in Claim 1, in which the load bearing means are pivotably mounted on the base so as to be rotatable to and from the load bearing condition.

3. A crane as claimed in Claim 1 or 2, further comprising an operating ram arranged to effect collapse and erection of the load bearing means.

4. A crane as claimed in Claim 3, wherein the operating ram is further arranged to control operation of the load bearing means in the load bearing condition.

5. A crane as claimed in Claim 4, in which the load bearing means comprise a support beam mounted on the base for movement between a collapsed condition and the load bearing condition, and a load bearing arm movable relative to the support beam, the operating ram being arranged to move the load bearing arm relative to the support beam.

6. A crane as claimed Claim 5, in which the operating ram is pivotably connected to and acts between the base and the load bearing arm for moving the load bearing arm relative to the support beam.

7. A crane as claimed in Claim 5 or 6, in which the load bearing arm is securable relative to the support beam for enabling the operating ram to effect collapse and errection of the load bearing means.

8. A crane as claimed in Claim 5, 6 or 7, in which the load bearing arm is spaced above the base when the load bearing means are in the load bearing condition.

9. A crane as claimed in any preceding claim, in which the retention means are arranged releasably to maintain the load bearing means in a selected one of a plurality of load bearing conditions.

10. A crane as claimed in Claim 9, in which the maximum reach of the load bearing means relative to a portion of the base is adjustable by altering the load bearing condition of the load bearing means.

11. A crane as claimed in any preceding claim, in which the retention means are arranged releasably to maintain the load bearing means in a collapsed condition.

12. A crane as claimed in any preceding claim, in which the retention means comprise a strut releasably connectible at one end to one of the load bearing means and the base and pivotably connected at the other end to the other of the load bearing means and the base.

13. A crane as claimed in Claim 12, in which said one of the load bearing means and the base has a plurality of connecting locations to which the strut is releasably connectible.

14. A crane as claimed in any preceding claim, in which the dimensions of the base are adjustable.

1 5. A crane as claimed in Claim 14, in which the maximum reach of the load bearing means relative to a portion of the base is adjustable by altering the dimensions of the base.

16. A crane as claimed in Claim 14 or 15, in which the base comprises a generally U-shaped support frame whose limbs are interconnected by a bridge portion which is selectively collapsible for adjustment of the spacing between the limbs.

1 7. A crane as claimed in Claim 16, in which the length of the base in the longitudinal direction of the limbs is reduced when the bridge portion is collapsed.

18. A crane as claimed in Claim 16 or 17, in which the bridge portion comprises a central member, and a pair of link elements, each of which is pivotably connected to the central member and to a respective one of the limbs.

1 9. A crane as claimed in Claim 18, further comprising a power unit mounted on one of the link elements, which unit is operable to control actuation of the crane from a location remote from the crane.

20. A crane as claimed in any preceding claim in which the base is mobile.

21. A crane as claimed in Claim 20 when appended to Claim 19, in which the unit is operable selectively to control one of actuation of the load bearing means and movement of the base.

22. A crane as claimed in any preceding claim, whose height is less than two feet when the load bearing means are in a collapsed condition.

23. A method for unloading an aircraft comprising providing a crane at a landing area for the aircraft, collapsing the crane during landing of the aircraft, re-erecting the crane when the aircraft is landed, and unloading the aircraft.

24. A crane constructed substantially as herein particularly described with reference to and as illustrated in the accompanying drawings.