GB2264292A

GB2264292A - Stacker crane.

Info

Publication number: GB2264292A
Application number: GB9301599A
Authority: GB
Inventors: Joerg Oser
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1992-01-28
Filing date: 1993-01-27
Publication date: 1993-08-25
Anticipated expiration: 2013-01-27
Also published as: GB9301599D0; ITMI930115A0; FR2686592A1; DE4202668C2; ITMI930115A1; DE4202668A1; IT1263816B; ATA17792A; FR2686592B1; AT404721B; GB2264292B

Description

2264292 STORAGE AND RETRIEVAL UNIT The invention relates to a storage and

retrieval unit. A storage and retrieval unit is known from European Patent 0329642 for loading containers onto or removing containers from shelves with a travelling device displaceable horizontally on a rail. The travelling device has a vertical mast, which is guided at its upper end on a further rail. A platform is vertically displaceable along the mast. A load accommodating means is arranged on the elevating platform, which can be extended and retracted horizontally by means of a drive motor arranged on the elevating platform. Stationarily arranged drive motors are provided for driving the mast in the horizontal direction and the elevating platform in the vertical direction. Power transmission from the drives to the travelling device and the elevating platform is effected via flexible traction elements guided by means of guide rollers, especially via cables, chains or toothed belts.

Since the mast is driven only on one side via the lower travelling device and is guided only at its tip, it is subject to oscillation stress during travel. This stress has therefore to be taken into account in the choice of dimensions for the entire mast and travelling device, especially the transition therebetween.

European Patent Application 0241189-A2 describes a storage and retrieval unit with a vertical elevating mast for loading shelf with small containers, especially video cassettes. The mast is horizontally displaceable, being guided at its upper and lower ends via linear ball bearings and driven by a traction mechanism. The traction mechanism is f ixed to the ends of the elevating mast twice at the sides thereof in the direction of travel and is guided by means of a plurality of rollers to a stationary drive arranged outside the displacement path of the storage and retrieval unit.

Because the traction mechanism is frequently deflected, this type of drive is only suitable for apparatuses of small structural size, i.e. with a small 2 absolute traction mechanism length, since only then are the drive forces evenly distributed at the two ends of the mast so that no inclination of the mast can arise.

German Utility Model 8607621 describes a palletizer for vertical movement of goods. The palletizer consists substantially of a stationary rectangular support frame, between whose vertical masts there is guided an elevating platform. A horizontally extendable fork is arranged on the elevating platform. Drive of the elevating platform and the f ork is ef f ected via a common drive motor. The drive motor drives a shaft arranged at the upper end of the support frame and running horizontally between the masts. When viewed from the drive motor, the shaft has arranged on it a first chain wheel, followed by a clutch and a second chain wheel with a braking device. The first chain wheel drives the fork via a revolving chain when the clutch is disengaged and simultaneously the braking device is actuated. When the clutch is engaged, the second chain wheel drives a chain which is fastened on the one hand to the elevating platform and on the other hand to a counterweight.

Although a common drive is provided for the elevating platform and the fork, this drive is effected via two, separate chains, the second chain being connected with a counterweight, and a clutch arrangement is necessarv between the chain wheels.

An elevator tower for garages is known from German Patent 1235560, which tower can be displaced horizontally in front of or between storage area rows arranged on several storeys. The vertical elevator tower is provided at one end with a drive which drives the tower via a roller supported on a rail. With very high towers, a parallel cable guide may be used in addition to this drive force transmission. This parallel cable guide consists of two traction elements tensioned horizontally and in parallel with the direction of travel of the tower as well as at their ends, the traction elements being in working 3 deflection connection with deflection rolls arranged at each end of the tower. A further endless traction element connects the rolls together. Although this document discloses the transmission of forces by means of a parallel cable guide, it relates to a different type of elevator tower and only to attenuation of oscillations arising from the travel motion of the tower.

Amongst the objects of the invention is the provision of a structurally simple storage and retrieval unit with improved travel properties, especially higher travel speed and better start-up and braking speeds.

A storage and retrieval unit, in accordance with one aspect of the invention, comprises a vertical mast displaceable horizontally by at least one travelling device, a vertically displaceable elevating platform guided on the mast, an extension unit arranged on the elevating platform for loading and unloading, a traction element connected with the elevating platform and drivable by means of a drive roll arranged at the mast foot, a driven roll on the elevating platform for moving the extension unit, the traction element being guided by a guide roll, arranged in the area of the mast tip, the drive roll and the driven roll, and a stop brake arranged between the mast and the elevating platform wherein the driven roll may be braked to allow transmission of the lifting force from the traction element to the elevating platform for vertical displacement thereof or the elevating platform can be fixed by means of the stop brake for movement of the extension unit, the driven roll thereby being released.

An advantage of this is that, through the use of only one drive for the elevating and extension movements in conjunction with two braking means arranged on the elevating platform, elimination of a further drive assembly for the extension movement is achieved. A considerable weight saving thereby results for the storage and retrieval unit, which has a particularly advantageous effect on the travel properties of the storage and retrieval unit.

4 Preferably the stop brake is f ixed to the elevating platform and connected with a stop gear, the stop gear being an engagement with a stop element arranged parallel to the longitudinal direction of the mast. A particularly suitable form for the stop element is as a chain.

The introduction of the braking f orce f rom the stop brake into the mast via a stop gear connected with the stop brake and a chain engaged with the latter and arranged on the mast is particularly advantageous as it leads to an especially play-f ree f astening of the elevating platf orm on the mast. In this way, a high degree of positioning precision of the elevating platform is made possible.

In a preferred embodiment the traction element is deflected in the area of the driven roll by means of two further guide rolls on the elevating platform in such a way that the traction element contacts the driven roll over at least 45'. The traction element may be a toothed belt.

The guidance of the traction element by means of deflecting guide and drive rolls arranged on the elevating platform for the movement of the extension unit, in such a way that the drive roll is contacted as far as possible by the traction element, and by at least approximately 45', ensures reliable introduction of the forces from he traction element into the drive roll.

The driven roll may be braked by a further stop brake thereon. The stop brake may be an open-circuit brake. The stop brake for fixing the elevating platform may be a closedcircuit brake.

Through construction of the elevating platform stop brake as a closedcircuit brake, the brake is also available as an elevating platform safety catch, for example if the traction element ruptures.

A storage and retrieval unit, in accordance with another aspect of the invention, comprises a vertical mast displaceable horizontally by at least one travelling device, a vertically displaceable elevating platform guided on the mast, an extension unit arranged on the elevating 1 platform for loading and unloading a shelf, and a traction element at the mast foot and the mast tip, the horizontally displaceable mast being driveable at both ends via the traction elements.

Fastening of the mast on both ends is achieved owing to the introduction of the drive forces into the mast foot and the mast tip via a traction element at each point. Through this fastening of the mast on both ends, oscillation of the mast tip is prevented and a lightweight mast may be used which has resultant positive effects on the travel properties. All the drive variants for the bilateral mast drive mentioned below provide the aforementioned advantages.

In one variant the mast drive traction elements are fastened to the mast foot and the mast tip at the front and rear sides respectively when viewed in the direction of travel and are guided via rolls which, when viewed in the direction of travel, are arranged at the ends of the travel paths of the -mast ends, at least one of the rolls being driveable by means of a drive. The driven guide roll(s) may be connected with an opposing guide roll via a further traction element.

In this variant, advantageously, one drive or travelling gear is provided at the mast tip and one at the mast foot, synchronization of the travelling gears is achieved by means of a common directional control.

In another variant the mast drive traction elements are fastened to the ends of the travel path of the mast ends, a drive roll being arranged at the mast foot and the mast tip, the drive rolls being in engagement with the traction elements, at least one roll being driveable by means of a travelling gear. The other drive roll may be connected with the driven drive roll via a further traction element.

In this variant synchronization mechanical coupling of the upper and elements via a further traction element.

is achieved by lower traction 6 Furthermore, the bilateral drive of the mast particularly advantageously enables the mast to be provided with only one running wheel, which is arranged at the mast foot and rolls over a rail. This construction is possible because, due to the fastening of the mast, the travelling device does not have to compensate for forces which may lead to inclination of the mast. As a result of the construction, a further weight reduction is achieved.

The combination of the two aspects, on the one hand of the alternating movement of the elevating platform and the extension unit via a common drive and on the other hand the bilateral drive of the mast via a traction element at each point, results in a storage and retrieval unit which is characterized by a particularly lightweight construction and the improved travel properties connected therewith such as good start-up speeds and high travelling speeds. The storage and retrieval unit is particularly suitable for use in hardware stores, in which working loads of up to approximately 25 kg have to be moved and the necessary mast height is approximately 6 m.

The advantageous use of toothed belts as traction elements leads to a reduction in the motion noise of the storage and retrieval unit.

The invention will now be described by way of example with reference to the accompanying drawings in which:- Figure 1 is a side view of a first embodiment of a storage and retrieval unit according to the invention; Figure 2 is a rear view of the mast and elevating platform, of the unit of Figure 1; Figure 3 is a plan view of the elevating platform of the unit of Figure 1; Figure 4 is a side view of a second embodiment of the storage and retrieval unit; Figure 5 is a side view of a third embodiment of the storage and retrieval unit; and Figure 6 is a side view of a fourth embodiment of the 7 storage and retrieval unit.

Figure 1 shows a storage and retrieval unit with a vertical mast 1. Travelling devices 2a and 3a are arranged at the mast foot 2 and the mast tip 3 respectively. The lower travelling device 2a substantially consists of a running wheel 4 rotatable about a horizontal axis, which running wheel 4 runs on a rail 5, and of two pairs oJE lateral guide rolls 6 rotatable about vertical axes. The upper travelling device 3a only comprises two pairs of lateral guide rolls 6, which roll against the sides of the web of a T-shaped guide rail 7, whose flange faces downwards.

The travel paths of the mast ends are defined by the rails 5 and 7 along which they move. The travelling devices 2a, 3a are each driven by a respective traction element 8, constructed in particular as a toothed belt. When viewed in the direction of travel of the mast 1, the traction elements 8 are fastened at one end to the front sides of the travelling devices 2a, 3a, run from there parallel with the rail 5 or the guide rail 7, are deflected by approximately 180' by means of deflecting guide rolls 9 arranged at the end of the rails 5, 7, guided to a deflecting guide roll 10 arranged at the other end of the rails 5, 7 and guided thereby to the rear sides of the travelling devices 2a, 3a for fastening. The rolls 10 can be driven by means of directionally controlled stationary electric drives, especially travelling gears 11 constructed as brushless rotary current servomotors. Electrical synchronization ensures synchronism of the upper and lower travelling gears 11.

A vertically displaceable elevating platform 12 is arranged on the mast 1. The elevating platform 12 is guided on the mast 1 by means of an elevating platform guide 12a formed of a plurality of rolls. The rolls constituting the elevating platform guide 12a run on guide rails (not shown) on the mast 1 of lightweight 8 construction. The elevating platform 12 can be displaced by a drive 19 arranged at the mast f oot 2. The drive 19 receives its control signals via a control mechanism 26 likewise arranged at the mast foot 2, which control -mechanism 26 is connected via infrared data transmission (M) to a control box 31 arranged at the end of the rail 5.

Figure 2, which is a rear view of the storage and retrieval unit, shows the guide of the traction element 13 for driving the elevating platform 12. The endless traction element 13 is guided via a drive roll 14 arranged at the mast foot 2, a deflecting guide roll 15 arranged at the mast tip 3 and a combination, arranged on the elevating platform 12, of a driven roll 16 and two further deflecting guide rolls 17, 18 to increase the angle of contact of the driven roll 16 to approximately 180'.

The large angle of contact is obtained in that the traction element 13 coming from the lower deflection roll 14 is deflected by approximately 900 by the deflection roll 17 arranged on the elevating platform, then deflected by approximately 180' by the drive roll 16, thereafter deflected again by 90' by the further deflection roll 18 and then guided to the deflection roll 15 in parallel with the mast. The axes of rotation of the rolls 14 to 18 run horizontally and parallel to the direction of travel of the mast 1. The drive roll 14 arranged at the mast foot 2 can be driven by means of a drive 19 (see Figure 1) arranged on the lower travelling device 2a, which drive 19 is connected to the drive roll 14 via an intermediate gear (not shown). The drive 19 is supplied with energy via a contact wire 32 arranged in parallel with the rail 5 and ending in the control box 31. By means of the contact wire 32, it is also possible to exchange the control signals between the mobile control mechanism 26 with the power electronics of the drive 19 and the stationary control box 31. This data exchange is here effected in the conventional manner via infrared data transmission.

Furthermore, the arrangement of a stop element 22 9 extending parallel to the mast 1 can be seen. The stop element 22 may be a chain, toothed belt or a rack. The stop element 22 is in engagement with a stop gear 23 arranged on the elevating platform and rotatable about a horizontal axis. Power transmission from the revolving traction element 13 to the upper deflection roll 15 can be used for the arrangement of a lifting weight overload safety device.

Figure 3 is a plan view of the elevating platform 12 of the storage and retrieval unit, which is guided on the mast 1. The driven roll 16 arranged on the elevating platform 12 is connected on the one hand via a shaft to the drive gear 20 to move an extension unit 25 and on the other hand via a shaft to a stop brake 21 supported on the elevating platform 12. Stop element 22, which is preferably constructed as a chain, is arranged integrally in a groove in the mast and is fastened to the mast foot 2 and the mast tip 3. A stop gear 23 arranged on the elevating platform 12 engages in this stop element 22, which stop gear 23 can be arrested by means of a further stop brake 24 supported on the elevating platform 12.

The stop element 22, in conjunction with the stop gear 23 and the stop brake 24 constructed as a closedcircuit brake, fulfils the function of an_ elevating platform safety catch in the case of power failure or an emergency shutdown.

With the aid of Figures 2 and 3, the manner of operation of the elevating and extension movements by means of a drive 19 will be described below. When elevating movement begins, the stop brake 24, which is constructed for reasons of safety as an electromagnetic closed-circuit brake which brakes by currentless connection, is released and the stop gear 23 is able to roll freely on the stop element 22 during the elevating movement. The elevating moment or lifting force is passed from the drive 19 into the driven roll 16 via the drive roll 14 and the revolving traction element 13. During the elevating movement of the elevating platform 12, the driven roll 16 is prevented f rom rotating by the stop brake 21. The driven roll 16 may also be stopped by arresting the deflection roll 17 or 18 and thus by means of the traction element 13. The load moment comprising the inherent elevating platform weight and the working load is passed into the elevating platform guides 12a via the traction element 13, the driven pinion 16 and the stop brake 21.

As soon as the elevating platform has reached its desired position in the vertical direction, the horizontal extension movement of the extension unit 25, which is constructed as a slide, may be initiated, to insert containers in or remove them from a shelf. To this end, the stop brake 24 is actuated by a control mechanism 26 arranged on the elevating platform 12, such that the stop gear 23 can no longer rotate relative to the elevating platform 12. The stop brake 21, which is constructed for reasons of weight as an electromagnetic open-circuit brake, is subsequently released and the self-weights of the elevating platform and the working load are transmitted to the stop element 22 via the stop gear 23. By releasing the stop brake 21, the driven gear 16 is then set in rotary motion relative to the elevating platform 12 under the drive of the endlessly revolving traction element 13, such that the drive gear 20 can be set in motion via the drive shaft for the horizontal extension movement of the extension slide 25.

Figure 4 shows a storage and retrieval unit at the upper and lower travelling devices 2a and 3a of which there are arranged travelling gears 11 which travel with the storage and retrieval unit. The travelling gears 11 are connected with a stationary traction element 8 via a drive roll or gear 28. A large angle of contact of the drive roll 28, with the traction mechanism 8 being ensured by means of deflection rolls 29, 30 likewise arranged on the travelling devices 2a, 3a, in a similar to the traction element guide on the elevating platform 12. The ends of 11 the traction elements 8 are fixed in the area of the ends of the rails 5 or the guide rail 7.

Figure 5 shows a further drive variant including a stationary gear 11. Guidance of the traction element 8 via the deflection rolls 9 and 10 corresponds to the construction according to Figure 1, but the drive 11 of the roll 10 on the guide rail 7 is replaced by a revolving traction element 27, which connects the rolls 10 with each other.

Figure 6 shows a further drive variant of the storage and retrieval unit in which the drive moves therewith. A travelling gear 11 is arranged on the lower travelling mechanism 2a. The drive force is transmitted similarly to the drive variant according to Figure 4, but power the drive roll 28 arranged on the upper is effected via a traction element 27 transmission to travelling device 3a connecting the drive rolls 28.

In the exemplary embodiment, the traction elements 8, 13 have been described as being advantageously constructed as toothed belts, but construction as chains or cables is also possible. Furthermore, construction of the stop element 22 as a rack or toothed belt is altogether feasible.

Claims

1. A storage and retrieval unit comprising a vertical mast displaceable horizontally by at least one travelling device, a vertically displaceable elevating platform guided on the mast, an extension unit arranged on the elevating platform for loading and unloading, a traction element connected with the elevating platform and drivable by means of a drive roll arranged at the mast foot, a driven roll on the elevating platform for moving.

the extension unit, the traction element being guided by a guide roll, arranged in the area of the mast tip, the drive roll and the driven roll, and -a stop brake arranged between the mast and the elevating platform wherein the driven roll may be braked to allow transmission of the lifting force from the traction element to the elevating platform for vertical displacement thereof or the elevating platform can be f ixed by means of the stop brake for movement of the extension unit, the driven roll thereby being released.

2. A unit as claimed in claim 1, wherein the stop brake is fixed to the elevating platform and connected with a stop gear, and wherein the stop gear is in engagement with a stop element arranged parallel to the longitudinal direction of the mast.

3. A unit as claimed in Claim 2, wherein the stop element is a chain.

4.

A unit as claimed in any preceding Claim, wherein a further stop brake is provided on the driven roll.

5. A unit as claimed in Claim 4, wherein the stop brake of the driven roll is an open-circuit brake.

6.

A unit as claimed in any preceding Claim, wherein the traction element is deflected in the area of the driven roll by means of two further guide rolls on the elevating platform in such a way that the traction element contacts the driven roll over at least 450.

7. A unit as claimed in any preceding Claim, wherein the stop brake for fixing the elevating platform is a closedcircuit brake.

8. A storage and retrieval unit comprising a vertical mast displaceable horizontally by at least one travelling device, a vertically displaceable elevating platform guided on the mast, an extension unit arranged on the elevating platform for loading and unloading a shelf, and a traction element at the mast foot and the mast tip, the horizontally displaceable mast being driveable at both ends via the traction elements.

9. A unit as claimed in any one of Claims 1 to 7, further comprising a traction element at the mast foot and the mast tip, the horizontally displaceable mast being drivable at both ends via the traction elements.

10. A unit as claimed in either Claim 8 or Claim 9, wherein the mast drive traction elements are fastened to the mast foot and the mast tip at the front and rear sides respectively when viewed in the direction of travel and are guided via rolls which, when viewed in the direction of travel, are arranged at the ends of the travel paths of the mast ends and wherein at least one of the rolls is drivable by means of a drive.

11. A unit as claimed in either Claim 8 or Claim 9, wherein the mast drive traction elements are fastened to the mast foot and the mast tip at the front and rear sides respectively when viewed in the direction of travel and are guided via rolls which, when viewed in the direction of travel, are arranged at the ends of the travel paths of the mast ends and wherein at least one of the rolls is drivable by means of a drive and the driven guide roll(s) is connected with an opposing guide roll via a further traction element.

12. A unit as claimed in either Claim 8 or Claim 9, wherein the mast drive traction elements are fastened to the ends of the travel paths of the mast ends, a drive roll being arranged at the mast f oot and the mast tip, the drive rolls being in engagement with the traction elements and drivable by means of a travelling gear.

13. A unit as claimed in either Claim 8 or Claim 9, wherein the mast drive traction elements are fastened to the ends of the travel paths of the mast ends, a drive roll being arranged at the mast foot and the mast tip, the drive rolls being in engagement with the traction elements and at least one roll being drivable by means of a travelling gear wherein the other drive roll is connected with the driven drive roll via a further traction element.

14. A unit as claimed in any one of Claims 8 to 13, wherein the travelling device moves on a rail and wherein a running wheel rotatable exclusively about a horizontal axis and running on the rail is arranged at the mast foot.

15. A unit as claimed in any preceding Claim, wherein the or each traction element is an endless toothed belt.

16. A storage and retrieval unit substantially as herein described and illustrated in the accompanying Figures.