WO1995019275A1

WO1995019275A1 - Container lift

Info

Publication number: WO1995019275A1
Application number: PCT/SE1994/000019
Authority: WO
Inventors: Kjell Ohlson
Original assignee: Hägglunds Vehicle Ab
Priority date: 1994-01-13
Filing date: 1994-01-13
Publication date: 1995-07-20
Also published as: NO962847D0; AU6158594A; EP0737136A1; FI962831A; NO962847L; FI962831A0

Abstract

Lifting arrangement (1) having a linearly extendable lift beam (2), in the centre of the arrangement journalled for pivoting movement to both sides in a vertical plane, through connection arms (10, 10') connected to a resp. support member (3, 4), the support members pivotally attached to opposing side areas of the arrangement for pivoting movement in a vertical plane and to a resp. side of the arrangement. Said lift beam and support members are pivotally attached to a horizontally disposed support beam (5), the arrangement being hydraulically operated and having a resp. cylinder (34, 34') interconnecting the support beam and support members for securing the support members in a lowered position wherein said members provide a rigid and non-pivoting extension of the support beam.

Description

CONTAINER LIFT

The present invention relates to a lifting arrrangement for transport goods upon loading/unloading, e.g. of a goods contai¬ ner, said lifting arrangement preferably being mobile and mounted on a transport vehicle.

In combined transporting on land there is a frequent need for goods transfer from one transport means to another, e.g. from sea freighters to lorrys or railway-wagons. Upon loading/unloading in freight stations and depots, as well as with the receiver/user of the goods, there is also a need for lowering the goods to ground or floor level. To increase the effectiveness of this time- and cost-consuming handling of transport goods, the transport industry aims to improve and rationalize its operations through an increasing use of different kinds of goods-carrying equipment, making it possible to handle piece goods as a group. Such goods carriers can be examplified by switch-bridges, freight containers, container-bottoms or "flats" etc.

The use of freight containers is wide-spread and has the advantages of a low cost through a simple construction, a high security in consideration of handling the goods and of unauthori¬ zed access to the goods as well, high flexibility in use not only for transporting, but also as long time storage and as mobile workshops etc.

The freight container is available in standardized lengths of 10, 20, 30 and 40 ft, and has gussets or receptacles in its upper and frequently also in its lower corners for the attachment of chain hooks and container yokes for lifting and for securing during transport. In harbours and switch yards, trackbound transversing cranes are mostly used to perform the lifting and transfer of goods, whereas there is a more frequent need for mobile lifting devices on transport vehicles in smaller sized depots and at receiving sites.

One existing mobile lifting device comprises two identical cranes, slidably arranged on a frame of a lorry or trailer. The spacing of the cranes is adjustable for use with containers of different lengths, e.g. 20 or 40 ft. These crane devices has telescopically extendable support members or legs, and are hydraulically operative and controllable from a remote control device.

Beside its many advantages, these devices also presents some obvious drawbacks, leading to the effort of developing a lifting arrangement in accordance with the present invention with the object of removing these drawbacks.

One of the disadvantages connected with abovementioned lifting device is its ability to load/unload cargo exclusively to one side of the towing vehicle, mostly to the left side of the lorry or trailer. It is realized that this lack of flexibility leads to time consuming dispositions in goods transfer and to less financial benefits from the operation. Furthermore, the operator is likely to get a feeling of uncertainty whereas the vehicle is to be advanced on the "wrong" side of the road, when loading/un¬ loading at a traffic loaded site.

Another disadvantage connected with the known device is that in loading/unloading operations the crane arm extends above the container up to a length of 600 mm, thereby reducing the operativeness on locations with a limited roofspace.

Abovesaid drawbacks with the known lifting device are removed in an arrangement in accordance with the present invention, comprising a telescopically and linearly extendable, centrally positioned and pivoting lift beam, through hydraulically driven and extendable connection arms pivotally connected to a resp. support member, arranged to pivot on both sides of the arrange¬ ment.

The object of the invention is therefore to provide a lifting arrangement for a transport vehicle, allowing for loading/unloa¬ ding to any desired side of the towing vehicle and not requesting any excessive roofspace when operating a cargo container at a location with limited roofspace.

Abovesaid object is met with an arrangement according to the attached claim 1.

In the following, embodiments of the invention are disclosed in detail and with reference made to the attached drawings, showing in:

Fig. 1 an elevational view from behind of a lifting arrangement according to the invention, with a hoisted container,

Fig. 2 a view in correspondance to fig. 1, the lifting arrange¬ ment shown with one support member lowered in preparation for transfer of the container to an adjacent transport vehicle or a loading platform, the lift beam extended to a maximum for visibility,

Fig. 3 the lowering of the container, stepwise and in three positions,

Fig. 4 the support member in an alternative embodiment, pivoted and extended to bear against the ground,

Fig. 5 the support member in another alternative embodiment, in resting and operative positions,

Fig. 6 a diagram of the hydraulic system which operates the lifting arrangement.

The lifting arrangement according to the invention is hereafter generally referred to as reference number 1. In operation, two parallell devices 1 are driven simultaneously, but as these, functionally and constructively are identical, only one of the two devices will here be described in detail. The lifting arrangement or lifting device 1 comprises four main elements: the lift beam 2, the support members 3,4 and a horizontally disposed support beam 5, in which the lift beam and support members are journalled for pivoting movement in a vertical plane. In the disclosed embodiment, the support beam 5 has a U-shaped cross section and receives, pivoting around a pivot 6, one resp. support member 3,4 in each end of the beam. In the center of the support beam 5, the lift beam 2 is pivoting on a pivot 7.

The lift beam 2 is telescopically extendable and has preferably a square cross section, alternatively though a cylindrical cross section can also be foreseen. The lift beam has a number of internal piston means 21,22. The extension/retraction of the piston means 21,22 is performed by a double-acting hydraulic cylinder 23. In its upper end, the lift beam 2 comprises a pair of attachment means 24,25, disposed on opposite sides of the lift beam. Said attachment means form the anchorage of a pair of telescopically extendable connection arms that interconnect the lift beam with each one of the support members, as described more in detail below. At the outer end of the innermost piston means 22 is applied an eye 26 adapted for the attachment of a chain with hooks, in operation anchored in the lower corner receptacles of the container, the chain shown in fig. 2 with a broken line 27. As an alternative to the chain, a container yoke can be applied and connected to the upper corner receptacles of the container. To a man skilled in the art the latter is a con¬ ventional procedure and is therefore not shown in detail in the drawings.

The support members 3,4 are identical in shape and construction, and only support member 3 will be described in detail and with reference made to fig. 2, wherein the support beam 5 is partly broken away for better visibility and disclosure of the con¬ struction of the lifting arrangement 1.

The support member 3 comprises a beam 30 with square cross section, preferably telescopically extendable by way of an internal, extendable piston means 31. The beam 30 has in its inner and lower end a pair of substantially triangular shaped plates 32, disposed in parallell and constituting a journal bearing for a pivot 6, as well as for a pivot 33, the later used for pivoting attachment of a hydraulic cylinder 34. The cylinder 34 is double-acting, the piston-end of the cylinder pivotally journalled in the support beam 5 on a pivot 35. The plates 32 has an angular shape that locates the pivot 33, disposed in the innermost apex of the triangular shaped plates in the upright resting position of the support member and facing the center of the lifting device, on the inner side of the longitudinal axis of the support member in said position. A favourable moment of force is thereby ensured for the cylinder 34, operative to secure the support member in its lowered position in which the support member can be said to constitute the base of a triangel formed by the pivots 6, 33 and 35.

In its outer, and in the resting position upper end, the support member 3 comprises a shoe 36 having an arcuate sole 37, and a pair of attachment means 38, arranged on the top side of the support member when lowered to the operative position. In an embodiment where the support member is extendable through the piston means 31, the shoe 36 is of course mounted in the outer end of said piston means.

One end of a connnection arm 10 is pivotally received in the attachment means 38, whilst the other end of said connection arm is pivotally received in the attachment means 24 of the lift beam 2. An identical connection arm 10' is correspondingly arranged between the attachment means 25 of the lift beam 2 and the other support member 4, the later comprising identical details as disclosed with reference to support member 3.

Transferring a container from a lorry, having a pair of lifting arrangements 1 according to the invention, includes the following steps as shown also in fig. 3 of the drawings: Support member 3 is lowered through extension of connection arm 10 until the support member bears on the ground or floor, in which position the support member is secured by actuating the hydraulic cylinder 34. In this secured position, the support member provides a rigid, non-pivoting extension of the support beam 5 through the fixedly positioned pivots 6, 33 and 35. The container is then hoisted through extension of the lift beam 2, until the container is floating above the lorry-bridge, in practice appr. 50 mm. This first step I is shown with continous lines in fig. 3.

Through a composite and coordinated movement, the lift beam 2 is lowered towards the support member, and simultaneously extended in order to maintain the container at a constant level during the movement, until the container is free of the lorry. Initially, the lift beam is pushed beyond the vertical line by activating the connection arm 10' on the opposite side of the vertical line, in order to displace the center of gravity towards the lowered and secured support member 3, the later gradually receiving an increasing part of the load upon the lowering and extension movement of the lift beam. In fig. 3 is shown in broken lines the second step II of the coordinated lowering/extending movement, whereupon the container is brought to swing freely at the side of the lorry.

At the end of the transfer movement the container is lowered, the lift beam 2 eventually extended to its maximum, down to the floor. This step III is shown in dash-dot lines in fig. 3.

It is understood that abovesaid transfer operation can be performed to any side, using the lifting arrangement 1 according to the invention. This way, a container can easily be trans¬ ferred, e.g. from one railway-wagon to another, the lifting device being positioned between the two wagons and therefore not requesting any cost-consuming dispositions or movements. Likewise, a container can easily be unloaded from a lorry-bridge, lowered to one side of the lorry whereupon a new container is loaded onto the lorry from the opposite side.

Since the lift beam 2 does not exceed the container-roof in height, loading/unloading can also be performed on locations with limited roof-space in a way that was not before possible by using the known lifting devices.

Conventionally, and without being shown in the drawings, it is to be understood that a lifting arrangement 1 according to the invention can be slidably mounted on a lorry-bridge and thus adaptible for containers of varying lengths and standards. As disclosed above, the lowering angle of the support member is limited by the length of the fully extended connection arm 10,10' , which makes this embodiment adapted to be used preferably in combination with a lorry-bridge of a kind that is hydraulical¬ ly activated to be lowered to the ground from a transportation level, through the operation of a link arms system. A such combination removes the need of a support member with an ability to bear on the ground, lowered from transportation height of the bridge. However, the later could also be an alternative em¬ bodiment, without departing from the scope of invention.

In an alternative and in fig. 4 disclosed embodiment the support member 3' ,4' is telescopic and extendable in multiple steps and comprises a pair of extendable piston means 41,42, and an internally arranged hydraulic cylinder 43 activating and controlling the extension of the piston means. The shoe 44 is e.g. pivotally attached at the end of piston means 42 as suggested in the drawing, thereby being adjustable to bear properly on the ground. It is clear that this embodiment might request a connection arm 10' having additional extension sections to provide the neccessary length for lowering the support member to a proper inclination to bear on the ground or floor.

In yet another embodiment, shown in fig. 5, the outer end of the support member 4' ' comprises a pivotally attached U-shaped beam 45, said beam being foldable to bear on the ground under formation of a "knee" of the support member with the connection arm 10' pivotally attached to the top of the knee. The web of the U-shaped beam 45 is of a length suitable to rest with the end edge of the web against the shoe 46 of the support member in the folded position of the beam 45, as is shown at 46 in fig. 5. The need for a connection arm of excessive length is removed in this construction. Securing the U-shaped beam in the folded position is e.g. performed through a linked rod 47, interconnecting the U-beam and the support member.

The lifting arrangement 1 is hydraulically actuated through a hydraulic pump, driven by the transport vehicle or by a separate drive unit. The two lifting devices of the vehicle are simultane¬ ously operated through valves, actuated in parallell, and the lowering and extension movements of the lift beam 2 are coordina¬ ted manually via remote control or automatically via a prestored control process and a joy-stick. Input to the automized process is provided by position indicating means, arranged to detect the lowering angle and extension of the lift beam and promoting a substantially horizontal transfer movement of the cargo contai¬ ner. Below is disclosed an embodiment of the hydraulic system, operating the lifting arrangement, with reference made to fig. 6 showing a hydraulic diagram.

The lifting arrangement 1 is operated in a load dependant hydraulic system and comprises a pump 102 delivering constant volume, driven by a motor 101, e.g. a motor of the transport vehicle. A pressure regulator 103 is used to balance the system and connects the system to the tank, thus preventing an overload when all directional switches 104-108 are in neutral positions. The system further comprises an accumulator 109 with pressure gauge, pressure regulator, actuating valve etc. as conventional and familiar to a man skilled in the art of hydraulics. The accumulator is pressurized over a biased non-return valve 110 and an actuator 111. The directional switch 104 activates the cylinder 34 on the left hand side of the drawing via a pair of non-return valves, applied to the piston and piston-rod sides, respectively. Said non-return valves are by-passed over a resp. pressure controlled regulator valve so that, upon extension of the cylinder 34, the non-return valve of the piston-rod side opens for back-flow as a result of the added pressure on the piston side. Similarly, the non-return valve of the piston side opens as a result of the added pressure on the piston-rod side upon retraction of the cylinder 34. In fig. 6, the regulator and non-return valves of the cylinder 34 are commonly referred to as 112 and the corresponding components of the cylinder 34' on the right hand side of the drawing, controlled by the directional switch 108, are commonly referred to as 113. If cylinder 34,34' is overloaded, the biased pressure regulator valve on the actual side of the piston opens, and in their neutral positions the directional switches 104 and 108 interconnect the piston and piston-rod sides as well as the tank.

The cylinder 23 of the lift beam is actuated through the directional switch 106, and comprises on the piston side a non¬ return valve and a pressure controlled regulator valve, in the drawing commonly referred to as 114. In the neutral position, the directional valve 106 is connected to tank.

The connection arms 10,10' are actuated through the directional valves 105 and 107, respectively. The connection arms are cross- connected, the valve 105 connecting in one position (see B in fig. 6) the pressurized side of the system to the connection arm 10', and in the same position setting connection arm 10 in fluid flow connection with the tank. From valve 105 to connection arm 10', the fluid is forced through a non-return valve which is by¬ passed over a biased pressure regulator valve, the later also controlled via the pressure of a pilot conduit (dashed line) which is linked to the conduit leading to connection arm 10, see reference number 115. In a second position of valve 105 (see A in fig. 6), the connection arm 10 is connected to the system pressure, and the pressure regulator valve 115 opens as a result of the added pressure of the pilot conduit, linked to the conduit of the connection arm 10, causing the connection arm 10' in fluid flow connection with the tank via the pressure regulator 115 and directional switch 105. In its neutral position, the later has a closed centre. A corresponding operation is found with the directional valve 107 and pressure regulator 116, the construc¬ tion leading to a composite and coordinated actuation and operation of the connection arms 10,10' upon lowering and raising of the lift beam 2.

Beside the components disclosed above the hydraulic diagram of fig. 6 also shows electro-magnetic and pressure-controlled directional switches and non-return valves for fast actuation of the lifting arrangement 1, e.g. to be used upon a reset to the resting position. A full disclosure of these components is however not required for an understanding of the operation of the arrangement. With reference to fig. 6 should also be mentioned that the accumulator 109, via pressure actuated non-return valves, flow control conduits and electro-magnetically controlled directional valves assembled into logical units 117, 118, 119 and 120, is connected to the cylinders 34,34' and to connection arms 10,10' to provide, when desired, an increased flow rate enough to operate the lifting arrangement at high speed in an unloaded situation.

The directional switches 104-108 are electro-magnetically actuated and can be operated via a remote control unit, hand held by the operator, as per se is known and conventional. Alternati¬ vely, the directional switches of the hydraulical system are operated by electric step motors controlled via signals from an actuating unit, said signals being modulated in a prestored control process and a processor in accordance with the actual positions of the operation cylinders, as detected by correspon¬ dent position detecting means. To the man, skilled in the art, this kind of operative control is a well known technology and in the current application used for controlling the extension of the lift beam 2 in relation to the pivoting angle, in order to provide a substantially horizontal movement of the cargo upon loading and unloading.

The invention is herein disclosed primarily with reference to a preferred embodiment, from which alterations are possible without departing from the scope of invention. Accordingly, the attached claims have been defined also to cover such variants that are not disclosed in drawings but still are obvious to a man skilled in the art. Such variants include e.g. a lift beam having circular cross section, pivotation of the lift beam and support members in spaced vertical planes, connection arms journalled to the front or back sides of the lift beam, a support beam having another cross sectional form than the disclosed U-shaped cross section etc.

Claims

1. Lifting arrangement comprising a lift beam and two support members, c h a r a c t e r i z e d in that

- said lift beam (2) being linearly, telescopically extendable and in the lower end pivotally attached to the arrangement (1) for pivoting, in a vertical plane, sidewards from a vertical resting position,

- the lower end of each support member (3,4) being journalled at the sides of the lifting arrangement for pivoting, in a vertical plane, sidewards and downwards from an upright resting position, and

- said lift beam (2) and support members (3,4) being interconnec¬ ted via a resp., telescopic connection arm (10,10').

2. Lifting arrangement according to claim 1, c h a r a c t e ¬ r i z e d in that

- the lift beam (2) is pivotally and centrally attached to a horizontally disposed support beam (5), the support members (3,4) being pivotally attached to a resp. end of said support beam (5).

3. Lifting arrangement according to claim 1, c h a r a c ¬ t e r i z e d in that

- the lift beam (2) is extendable through an internal, double- acting hydraulic cylinder (23) and preferably includes two extendable piston means (21,22),

- the connection arms (10,10') are hydraulically driven tele¬ scopic cylinders, and

- each support member (3,4), in the pivoted and lowered position fixed through a resp. hydraulic cylinder (34,34').

4. Lifting arrangement according to claim 1,2 and 3, c h a ¬ r a c t e r i z e d in that

- the lift beam (2) comprising a rectangular or square cross section and two attachment means (24,25), disposed on opposite sides of the lift beam and an eye (26) in the outer end of the innermost piston means (22), - each support member (3,4) comprising a rectangular or square cross section and being telescopically extendable through at least one internal piston means (31), preferably driven by an internal, double-acting hydraulic cylinder (43), the outer end of said piston means having a shoe (36) with an arcuate sole (37) and the inner end a resp. substantially triangular plate (32) for the journalling of a pivot (6), pivotally attaching the support member to the support beam ( 5), as well as a pivot (33), pivotally attaching the cylinder (34,34') to the support member (3,4), the other end of each cylinder pivotally attached to the support beam ( 5), and

- each connection arm (10,10') in one end pivotally attached to the attachment means (24,25) of the lift beam (2) and in the other end pivotally attached to additional attachment means (38), disposed on top of the support member (3,4) in the lowered position.