EP0776307A1

EP0776307A1 - Goods handling crane

Info

Publication number: EP0776307A1
Application number: EP95932266A
Authority: EP
Inventors: Lars-Ake Larsson
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-09-12
Filing date: 1995-09-06
Publication date: 1997-06-04
Also published as: WO1996008430A1; SE9403026D0; SE9403026L; NO971105D0; SE503421C2; AU3536095A; NO971105L

Abstract

The invention relates to a goods handling crane which is horizontally movable along storage shelves to take goods out of and deliver goods into these, comprising a travelling carriage (2), a lifting stand (3) on the travelling carriage, a lifting arrangement (4) for goods, a first driving means for moving the goods handling crane in the horizontal direction along the storage shelves and a second driving means for raising and lowering the lifting arrangement in the vertical direction along the lifting stand. The characteristic feature is that said first driving means comprises at least one driving motor and at least one longitudinal traction device (22) which is arranged to act on the goods handling crane, more specifically on the lifting stand (3) between the travelling carriage and the top of the stand at a considerable height above the travelling carriage, and in that said traction device is situated at least on one side of the goods handling crane along the horizontal travelling direction thereof at a distance from the centre line of the goods handling crane which is sufficient for allowing the lifting arrangement to pass said traction device on its vertical movement along the lifting stand.

Description

GOODS HANDLING CRANE

TECHNICAL FIELD The invention relates to a goods handling crane which is horizontally movable along storage shelves and to take goods out of and put goods into these, comprising a travelling carriage, a lifting stand on the travelling carriage, a lifting arrangement for goods, a first driving means for moving the goods handling crane in the horizontal direction along the storage shelves and a second driving means for raising and lowering the lifting arrangement in the vertical direction along the lifting stand.

BACKGROUND OF THE INVENTION

Goods handling cranes of the type indicated above can be very tall in order to be capable of being used on tall storage shelves and there are examples of goods handling cranes which are several tens of metres tall. The horizontal movement of the goods handling crane takes place with known art normally by the generally rail-mounted travelling carriage being moved by the wheels of the travelling carriage being driven or by means of longitudinal traction devices in the form of belts, wire cables, chains or corresponding acting on the travelling carriage or at the very bottom of the lifting stand, the goods handling crane being pulled by means of a motor which acts on the belts, the wire cables, the chains or corresponding. In this connection, the motor or the motors which pulls or pull the goods handling crane can either be situated on the travelling carriage/the goods handling crane or be firmly mounted at the end or the ends of the movement path of the goods handling crane.

With thjs known art, the force for the horizontal movement of the goods handling crane acts close to the lowest part of the goods handling crane. In the case of very tall lifting stands - lifting stands up to 40 m tall exist - this means a very unfavourable force load with a great moment acting on the lifting stand on acceleration and retardation of the goods handling crane. This in turn means that the lifting stand is subjected to oscillatory movements which must cease before the goods handling crane can be said to have been positioned for delivering and taking out goods to and from one of the shelf compart¬ ments. In order to avoid such oscillatory movements, the acceleration and the retardation of the horizontal movement of the goods handling crane must be limited, which of course reduces the handling speed. Alternatively, the lifting stand must be constructed to be more stable so that it has a higher moment of inertia, which, however, leads to higher manufacturing costs and greater mass which in turn requires great motor power for acceleration and retardation.

From US 3 690 479, a goods handling crane is also known which is moved in the horizontal direction by wire cables which are fastened to the goods handling crane at a height corresponding to the vertical centre point of the goods handling crane. The prerequisites are thus created for being capable of reducing the abovementioned oscillatory movements. Characteristic of the goods handling crane according to US 3 690 479, however, is further that it is moved in the horizontal direction by a motor arranged remote from the goods handling crane, from which the goods handling crane is driven via a wire cable which is fastened at a front and a rear point on the goods handling crane which together with the cable forms an endless loop, the path of which is defined by a number of guide wheels. The lifting stand of the goods handling crane is relatively broad in the travelling direction which means that the lifting handling crane can be moved in the vertical direction between the fastening points of the cable. At the same time, however, this construction also means that the goods handling crane has a very stable and thus heavy construction with the disadvantages this implies, which have been discussed above. Another disadvantage is that the driving wire cable must have a considerable length. As a result of the pulling force in the cable, in such a construction it is not possible to avoid considerable elastic, varying extensions in the wire cable, which impairs the precision and/or the speed in the positioning of the goods handling crane. The hanging-down of the cable also leads to impaired precision, especially as it is not possible in the known construction to prevent hanging down by means of support arrangements. This applies at least to the part of the cable which extends between the goods handling crane and the drive motor at one end point of the transport path and between the goods handling crane and the first guide wheel at the other end point of the transport path.

The aim of the invention is to offer an improved goods handling crane which does not have the abovementioned disadvantages and/or limitations. These and other purposes can be achieved by said first driving means comprising at least one driving motor and at least one longitudinal traction device which is arranged to act on the goods handling crane, more specifically on the lifting stand between the travelling carriage and the top of the stand at a considerable height above the travelling carriage, and by said traction device being located at least on one side of the goods handling crane along the horizontal travelling direction thereof at a distance from the centre line of the goods handling crane which is sufficient for allowing the lifting arrangement to pass it on its vertical movement along the lifting stand. The traction device is preferably arranged to act on the lifting stand at a height corresponding essentially to the centre of gravity of the goods handling crane exclusive of the weight of the vertically movable lifting arrangement.

The longitudinal traction device can e.g. consist of a driving belt, wire cable, chain or corresponding. In principle, it is also possible to envisage a rack interacting with gearwheel and driving motor on the goods handling crane.

Preferably, the driving motor which forms part of the first driving means for the horizontal movement of the goods handling crane is expediently arranged on the goods handling crane, preferably on the lifting stand, and arranged to act via a transmission on said traction device/traction devices which is/are firmly clamped between fastening points at both ends of the transport path. More specifically, the traction device/traction devices, e.g. the behJbelts or corresponding, is/are clamped between the fastening points, i.e. subjected to a given pulling tension, which contributes to giving very high precision in positioning. The invention also makes it possible for a driving belt or corresponding arranged in this manner to be supported by one or more support arrangements, e.g. a rail, which extend horizontally along the entire length of the storage shelves. This possibility is used in the preferred embodiment of the invention, as a result of which the belt or corresponding traction device is prevented from hanging down, something which would impair the precision.

All the features which distinguish the goods handling crane according to the invention contribute to being capable of being accelerated or retarded very powerfully, which is of extraordinary significance for rapid manoeuvring and positioning of the goods handling crane. In a comparative example, it has been possible to increase the acceleration and the retardation of the goods handling crane from approximately 0.4 m/s , which is a normal value for a goods handling crane which is driven horizontally by means of the travelling carriage on which it is moved, to approximately 6 m/s . This considerably increases the goods handling speed. At the same time, it has been possible to make the precision in positioning very accurate, approximately ± 1 mm, and the adjustment very rapid, which also contributes to achieving a high goods handling speed. It has also been possible to make the travelling carriage shorter and provide it with fewer wheels, which also contributes to it having been possible to make the entire construction smaller with weight-saving and lower requirements for motor power as a consequence. Further characteristic features and aspects of the invention will be apparent from the appending patent claims and from the following description of a preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS In the following description of a preferred embodiment, reference will be made to accompanying drawings, in which

Fig. 1 shows a schematic picture of a goods handling crane according to the invention, Fig. 2 shows motors and parts of the transmissions which are arranged to pull the goods handling crane in the horizontal direction and which move the lifting arrangement in the vertical direction, Fig. 3 shows, in the direction of arrow A in Fig. 1, the lifting stand in a cross-section and parts of said first driving means for the horizontal movement of the goods handling crane, and Fig. 4 shows corresponding parts in a view in the direction of arrow B in Fig. 1.

DETAILED DESCRIPTION OF THE INVENTION

With reference first to Fig. 1, a preferred embodiment of the invention is shown, in which the goods handling crane 1 comprises a travelling carriage 2, a lifting stand 3 and a lifting arrangement 4 with goods 5. A motor 6, which forms part of said first driving means, acts on a- longitudinal first traction device which is in the form of a toothed belt 22 on one longitudinal side of the goods handling crane by means of a driven gearwheel 11 and guide wheels 12 and 13. The toothed belt 22 is made of steel- wire reinforced plastic and rests with the teeth facing downwards on a rail 28 which is fastened to vertical posts 29 forming part of the storage shelves 30. The toothed belt 22 is thus prevented from sagging down, which would impair the possibilities of positioning the goods handling crane rapidly with great precision. The toothed belt 22 is furthermore firmly anchored with its two ends at fastening points 31, 32 close to the two end positions of the goods handling crane 1 and is extended, i.e. subjected to pulling tension, between these fastening points, which is also positive for exact and rapid positioning. On the other longitudinal side of the goods handling crane, there is a corresponding arrangement (Fig. 3 and Fig. 4) in which the same motor, by means of a driven gearwheel 11' and guide wheels 12' and 13', acts on a second toothed belt 22' resting on a second fixed rail 28'.

The lifting arrangement 4 with any goods 5 is moved vertically along the lifting mast 3 by means of a motor 14, a driving wheel 19 driven by the motor 14 and guide wheels 20 and 21 and e.g. a belt, wire cable, chain or corresponding 23. The arrangements 4, 14-21 and 23 do not constitute part of the invention and are not described in detail in this text.

Figs 2, 3 and 4 show motors, transmissions and other arrangements for the horizontal movement of the goods handling crane and for the vertical movement of the lifting arrangement. The motor 6 is provided with a belt pulley 7 which is connected via a belt 8 to a second belt pulley 9. This is mounted on an axle 10 which is at each end provided with the gearwheels 11 and 11' respectively. The drawings also show guide wheels 12 and 13, and 12' and 13' respectively, which, like the driving wheels 11 and 11', are partly surrounded by sections 32, 32' of the belts 22 and 22' respectively and lay the belts on the respective rail 28, 28'.

The travelling carriage 2 of the goods handling crane is provided with wheels 25, 26 and 25', 26' which are made as rail-mounted travelling and guiding wheels. There is moreover a pair of guiding wheels at the top of the lifting stand.

The lifting stand 3 of the goods handling crane 1 is supported at the top 24 in the transverse direction by means of one or more rails which prevent the lifting stand from swaying laterally.

The goods handling crane 1 is moved horizontally with the travelling carriage 2 rolling on rails (not shown) horizontally as the arrows show to the desired position where goods, after vertical movement and very accurate positioning of the lifting arrangement, are automatically taken out of or delivered into storage shelves 30, 30' situated on both sides along the travelling direction of the goods handling crane 1.

The horizontal movement takes place in the preferred embodiment by the motor 6 driving, via the belt pulley 7, the belt 8, the belt pulley 9 and the axle 10, the two gearwheels 11 and 11', one on each of the sides of the goods handling crane which face towards the storage shelves 30, 30'. The driving wheels 11 and 11' are, by means of the guide wheels 12, 13 and 12', 13', partially surrounded by belt parts 32, 32' of the tensioned belts 22 and 22'. On rotation of the motor 6 and through the engagement of the partially surrounded gearwheels 11, 11' with the teeth in the fixed, tensioned toothed belts 22, 22', the goods handling crane 1 is moved along the tensioned belts in the horizontal direction to a position, in which the lifting arrangement is in a desired horizontal position in front of a desired storage place (if appropriate the vertical position of the lifting arrangement is taken up simultaneously with the horizontal movement of the goods handling crane so that the lifting arrangement 4 is in the desired place when the goods handling crane 1 stops). By means of the preferred embodiment with two toothed belts 22, 22' adjacent to the storage shelves 30, 30', the lifting arrangement 4 can be moved vertically unhindered to the correct height without being blocked by the toothed belts 22 and 22', whether the vertical movement takes place after the goods handling crane has stopped or - preferably - simultaneously with the goods handling crane 1 being moved horizontally.

It will be understood that the invention can be varied within the scope of the invention. Certain modifications have already been mentioned above, e.g. selection of traction devices other than belts, the arrangement of the motor or motors outside the goods handling crane etc., although the arrangement described is to be preferred. Among other modifications, mention can be made of the lifting stand being placed at or close to one side of the travelling carriage instead of centrally. Furthermore, it is in principle possible to make the lifting stand sloping, e.g. forwards/backwards or towards the side instead of entirely vertical or arrange two masts in tandem on the travelling carriage, which can be appropriate especially in the case of heavier goods handling cranes. As far as the traction device/traction devices are concerned, it is expedient that these are made as a toothed belt/toothed belts, especially when they are supported by a support arrangement, but other alternatives have also been mentioned in the text, such as wire cables, chains and racks. It will be understood that the support arrangement in the form of a rail can be modified, e.g. made as a longitudinal channel. A rack is also possible as traction device, which can be carried by brackets or other support arrangements along the storage shelves. What it is desired to protect through the patent is therefore not to be limited by the preceding, detailed description of a possible embodiment.

Claims

1. Goods handling crane which is horizontally movable along storage shelves to take goods out of and deliver goods into these, comprising a travelling carriage (2), a lifting stand (3) on the travelling carriage, a lifting arrangement (4) for goods, a first driving means for moving the goods handling crane in the horizontal direction along the storage shelves and a second driving means for raising and lowering the lifting arrangement in the vertical direction along the lifting stand, characterized in that said first driving means comprises at least one driving motor and at least one longitudinal traction device (22) which is arranged to act on the goods handling crane, more specifically on the lifting stand (3) between the travelling carriage and the top of the stand at a considerable height above the travelling carriage, and in that said traction device is situated at least on one side of the goods handling crane along the horizontal travelling direction thereof at a distance from the centre line of the goods handling crane which is sufficient for allowing the lifting arrangement to pass said traction device on its vertical movement along the lifting stand.

2. Goods handling crane according to Claim 1, characterized in that said first driving means comprises at least one longitudinal traction device on each side of the goods handling crane along the horizontal travelling direction thereof, which traction devices are arranged with a distance between them which is sufficient for allowing the movable lifting arrangement (4) to pass between them on its vertical movement and handle goods in storage shelves on one or both sides of the goods handling crane.

3. Goods handling crane according to Claim 1 or 2, characterized in that said traction device consists of a belt, wire cable, chain or corresponding.

4. Goods handling crane according to Claim 1 or 2, characterizedin that said traction device consists of a rack.

5. Goods handling crane according to any one of Claims 1-4, characterizedin that said at feast one driving motor forming part of said first driving means is situated on the goods handling crane and arranged to act against said traction device(s) which is/are fastened at its/their end/ends at the ends of the movement path of the goods handling crane.

6. Goods handling crane according to any one of Claims 1-4, characterizedin that the motor/motors is/are situated remote from the goods handling crane, in continuation of the travelling direction of the goods handling crane and in that the traction devices in the form of belts, wire cables, chains or corresponding which are arranged to pull the goods handling crane are immovably fastened to the latter.

7. Goods handling crane according to any one of Claims 1-6, characterized in that said traction device extends past the goods handling crane at the side/sides of the latter between the goods handling crane and the storage shelves, preferably adjacent to the storage shelves.

8. Goods handling crane according to any one of Claims 1-7, characterizedin that the belt^/belts or corresponding rest on one or more support arrangements along the storage shelves.

9. Goods handling crane according to Claim 8, characterized in that said support arrangement consists of a rail which extends horizontally along the storage shelves.

10. Goods handling crane according to any one of Claims 1-9, characterized in that said traction devices are tensioned, i.e. subjected to given pulling tension between their fastening points.

11. Goods handling crane according to any one of Claims 1-10, characterized in that said traction device consists of a toothed belt/toothed belts with the teeth resting on said support arrangement, in that said first driving means comprises a gearwheel (11) driven by said driving motor at a given height above the toothed wheel and also a pair of guide wheels (12, 13) arranged to bear against the toothed belt lying on the support arrangement, and in that the toothed belt extends in a loop (32) up over the gearwheel between the two guide wheels.