BACKGROUND ART

Multi-level storage facilities, for instance to store and retrieve motor vehicles, are known in the art.

One early reference is U.S. Patent 2,794,559 in the name of Walker E. Rowe published in 1957. This system showed a multi-level automobile parking and storage apparatus which essentially consisted of an serpentine track formed from steel channel. The track had vertically spaced horizontal courses interconnected by a vertical turn. A number of large drive wheels having a diameter of about

4.4mm located in the vertical turns, and the drive wheels could be synchronised. The track guided a linked drive chain which was formed from a number of long, straight, pivotally coupled link members. The pivot connection was required to allow the drive chain to pass through the vertical turn from one horizontal course to an adjacent horizontal course. A number of cubicles could be attached to the drive chain. The cubicles needed to be spaced apart by a fair distance such that the cubicles would not collide with each other as they moved along the vertical turn. The Rowe system had a number of disadvantages including difficulties associated with the drive chain during the vertical turn, and the need for the track to invert along the vertical turn. The track was also not continuous and quite large gaps were required adjacent an upper portion of the vertical turn.

With the large drive wheels, the overall density of cubicles per area was not that much different to conventional carparks which require 92 cubic metres per car space.

In my two earlier patent applications,

PCT/AU91/00220 and PCT/AU92/00581, I developed a storage facility which comprised a true endless loop (no breaks in the track) and was driven by end wheels through the vertical turn. In my earlier International patent applications, the wheels had pick-up arms, and as the speed of the cubicle passing through the vertical was different to the speed in the horizontal, there were still various disadvantages apparent in the pick-up arms and the drive chain. The cubicles were de-coupled from the drive chain during their passage along the vertical turn and were then re-coupled to the drive chain. The facility in my earlier patent applications did however improve the car space density to 67 cubic metres per car space. OBJECT OF THE INVENTION

The present invention is directed to a storage system where the difficulties previously encountered have been substantially overcome by providing a variable length drive chain. In this manner, the inherent difficulties and disadvantages with the previous systems can be reduced.

It is an object of the invention to provide a storage system which may overcome the abovementioned disadvantages or provide the public with a useful or commercial choice.

In one form, the invention resides in a multi¬ level storage system comprising a pair of spaced apart parallel tracks defining an endless loop having longitudinal courses separated by a turn, each track guiding a variable length drive chain, a plurality of storage cubicles positioned generally between the tracks, each cubicle being attached to both drive chains, a drive means to drive the cubicles in a desired direction along the endless loop, characterised in that the drive chain lengthens as it passes through the turn.

In another form, the invention comprises a variable length drive chain, the drive chain comprising connected sets of in-line wheels and displaceable wheels,

the displaceable wheels being displaceable between an in¬ line position where the wheels are generally between the in-line wheels to lengthen the drive chain, and a spaced position where the displaceable wheels are spaced from the in-line wheels to shorten the drive chain.

By having the drive chain lengthening as it passes through the turn, it is no longer necessary to de¬ couple the cubicles and the cubicles can remain attached to the drive chain at all times. It is preferred that each drive chain comprises connected sets of in-line wheels and sets of displaceable wheels, the displaceable wheels being displaceable between an in-line position where the wheels are generally between the in-line wheels to lengthen the drive chain, and a spaced position where the displaceable wheels are spaced from the in-line position to shorten the drive chain.

The cubicles are preferably attached to a set of the in-line wheels of the drive chain and, depending on the width of the cubicles, there may be a number of intermediate in-line wheels between sets of in-line wheels to which the cubicles are attached.

It is preferred that at least some of the in¬ line wheels comprise bogies. The bogies can have a pair of interconnected in-line spaced apart wheels, and the wheels may be interconnected by metal plates extending along each side of the wheel. The plates may be proud of each wheel such that when adjacent bogies contact each other, contact is made between the metal plates and not between the wheels.

Suitably, at least one displaceable wheel interconnects at least some adjacent in-line bogies. Preferably, the drive chain comprises a large number of in-line bogies and the bogies are connected to each other through a displaceable wheel set. Although it is preferred that the displaceable wheel set comprises a single wheel, it is possible for a number of wheels to also comprise the displaceable wheel set.

To provide stability to the cubicles, the cubicles may be attached to a bogie on each drive chain, and preferably are attached between the pairs of interconnected wheels on each bogie such that each wheel in the bogie shares an approximately equal amount of load.

The cubicles may be pivotally attached relative to the drive chain.

The displaceable wheels may be rotatably attached to rigid link arms. Each displaceable wheel may have a pair of rigid link arms pivotally connected relative to each other. Each pivot link arm may also be pivotally connected to an adjacent set of in-line wheels. To facilitate displacement of the displaceable wheel set, it is preferred that the displaceable wheel is of larger diameter than the in-line wheel.

With the arrangement of a variable length drive chain, it is possible to interlock or abut adjacent cubicles together, or have them closely spaced apart so that more cubicles per length of drive chain can be made available than hitherto possible. It is also possible to achieve a density of 40 cubic metres per car space.

To aid in, or to cause lengthening of the drive chain as it moves along the vertical turn, the track may decrease in size adjacent the vertical turn where a said cubicle moves from one course to an adjacent course. As the track narrows or decreases in size, it acts upon the displaceable wheel to push the displaceable wheel into an in-line position causing lengthening of the drive chain. The drive means may comprise one or more drive wheels. If drive wheels are used, they may be positioned in or adjacent one or more of the turns. The drive wheels may have couplings to allow them to engage with the drive chain and/or the cubicle to pull or push the cubicle and/or the drive chain along the vertical turn.

Alternatively, the drive means may comprise a rotating screw thread adjacent and above a horizontal portion of the drive chain which can engage with some of

the wheels such that rotation of the screw thread causes movement of the drive chain.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described with reference to the following drawings in which

Figure 1 illustrates a multi-level storage system according to an embodiment of the invention.

Figure 2 shows a larger version of Figure 1. Figure 3 shows a close-up of a drive wheel in a vertical turn.

Figure 4 shows an alternative drive chain.

Figure 5 shows a multi-level storage system where the tracks extend substantially vertically. This system is identical to the horizontal system except that the cubicles move along vertical courses rather than horizontal courses.

Figures 6 - 10 illustrate moveable platforms which can move in and out of a cubicle.

Figure 11 illustrates a car on a horizontal plate system.

BEST MODE

Figure 1 illustrates a simple multi-level storage system. The storage system has a number of cubicles 10 in a horizontal course 14, and a pair of cubicles 10A, 10B going through a vertical turn 13 (these can be called "vertical cubicles") . Cubicles 10 can be formed in any convenient manner and reference may be had to my earlier patents for guidance. The cubicles may be formed from steel or other metal and can be sized, shaped and dimensioned to accommodate cars, boxes, or anything else that needs to be stored. It can be seen from Figure

1 that the cubicles are, if not abutting together, very closely spaced apart which means that the maximum number of cubicles per length of drive chain can be used resulting in a high efficiency of the entire system. The cubicles are attached to a drive chain 11 which is itself guided within a steel track 12. The track, and the drive chain, are endless, and in Figure 1 the track and guide

chain comprise a simple single loop.

In the embodiment, the track can be formed from steel C-section, but it should be appreciated that the tracks could also be alloy, and different shapes for example angle, I-beams, U-beams, or of a tubular construction.

Drive chain 11 is of variable length by which is meant that the length of the drive chain, as it goes through the vertical turn 13, lengthens compared to the length of the drive chain as it passes along a horizontal course 14.

In this embodiment, the variable length drive chain comprises connected sets of in-line wheels 15 and sets of displaceable wheels 16. The in-line wheels remain in line along the entire length of the track which can be seen in Figure 1, while the displaceable wheels 16 can be displaced between an in line position as they pass through the vertical turn (see Figure 1) , and a spaced position where the wheels are above (or below) the in- line wheels 15.

Figure 1 therefore clearly shows how the length of the entire drive chain 11 can vary depending on the position of the displaceable wheels. That is, when the displaceable wheels are more in line, they cause the drive chain to lengthen and when the displaceable wheels are more out of line, they cause the drive chain to shorten.

It is preferred that the in-line wheels 15 are formed from a number of bogies 17. Each bogie is formed from a pair of in-line spaced apart wheels interconnected by a metal plate, the in-line wheels being rotatably mounted to an axle which is journalled or otherwise attached to the metal plate. As evident in Figure 1, it is preferred that the metal plates extend proud of the bogie wheels such that when adjacent bogies touch, contact is made via the metal plates and not by wheels rubbing together (it being appreciated that the leading wheel of one bogie rotates in the opposition direction to

the trailing wheel of an adjacent bogie) .

Displaceable wheels 16 are rotatably mounted to a pair of rigid link arms 18, 19. Link arms 18, 19 are pivotally attached to each other and this point also forms the pivot point of the displaceable wheel 16. Each link arm 18, 19 is also pivotally attached to a bogie such that adjacent bogies are interconnected through link arms 18, 19 and thus through a displaceable wheel 16.

Referring to Figure 1, if the drive chain shown therein moves in a clockwise manner, the lower portion 20 of the drive chain and the upper portion 21 of the drive chain comprises abutting moving bogies 17. In the vertical turns 13, the drive chain has been lengthened to include the displaceable wheels 16. To facilitate lengthening of the drive chain, track 12 narrows at 21 to guide the displaceable wheel 16 to an in line position. The track remains narrow through the vertical turn and broadens again at 22 to allow the displaceable wheel to now move back to its spaced position. It is possible to regulate the dimensions of track 12 which in turn can regulate the spaced position of wheels 16. However, it is also possible to have the dimensions of track 12 large enough such that wheels 16 do not contact the walls of the track when the wheels are in the position where they are spaced above the bogies.

Figures 1 and 2 show that the cubicles 10, when in the horizontal course, have edges 10B which overlap each other. The edges are the tubular rods which make up the cubicle side walls. One edge of a cubicle is longer than the other edge. That is the distance between the front and rear tubular rod on one edge of a cubicle is less than the distance between the front and rear rod on the other edge. This allows the cubicles to interlock, or put otherwise, to slightly nest into each other. The purpose of this is to reduce swaying of a cubicle as it is being loaded. As a cubicle moves through a vertical turn, the drive chain lengthens, and because the cubicle is attached to the drive chain, it separates from its

adjacent cubicle (see Figure 1) .

Figures 1 and 2 illustrate a preferred drive means which is in the form of a number of rotatable drive wheels 21. Wheels 21 can be driven either independently or together and can be synchronised. Wheels 21 are journalled to a shaft 22, and are substantially circular. The wheels are provided with couplings in the form of peripheral recesses 23. The peripheral recesses are spaced apart to correspond with engagement pins or shafts on the drive chain and/or cubicles. In Figures 1 and 2, the cubicles are attached to a bogie on the drive chain. Also, the cubicles are attached to the bogie in between the bogie wheels such as to provide equal load on each wheel . The wheels of the intermediate bogies (that is the bogies that are not attached to cubicles) , touch each other in the centre and the connecting arms to the cubicle bogie (that is the bogie supporting a cubicle) , are connected to the cubicle wheel shafts via a partially rotating rod which allows for adjustments in length which occur in the vertical curves.

This also allows the displaceable wheel to raise in the horizontal and in that way reduce the chain length in the horizontal between cubicle shafts. Over the distance in the angled transition distance between the narrow and wider track in the horizontal, the increase or decrease in the speeds between the horizontal and vertical takes place gradually and smoothly. When the cubicle shafts connections are in the top and bottom position of the drive wheel, the drive chain length in the curve is % of the wheel circumference or the distance between the next cubicles in the horizontal remains fixed at the cubicle width/distance between the cubicle shafts.

The height of the track in the horizontal can be made slightly adjustable to allow for wear and tear and adjustment during the commissioned time.

The angled section of the track can also be adjusted to allow more or less space between the cubicles as they pass through the vertical curve. In addition, at least one set of connecting arms between the bogie shafts can also be made adjustable in length.

The tracks can be square, tubular, rectangular or combinations of all with or without separate tracks for the bogie wheels.

If one of the drive wheels 21 pushes the next cubicle in the horizontal, the following drive wheel will pull the following cubicle into the horizontal and the actions are opposite to each other in the top and bottom tracks. Synchronisation can be maintained by the installation of cross-shafts geared to the drive wheels or by sprocket chain or tooth belts.

It can be seen that unlike other systems, the cubicles are connected to the drive chain at all times and are not lifted away from the drive chain the vertical turn as previously required. By slightly adjusting the height between the top and bottom of the horizontal track section, the travel length can be increased or decreased or adjusted for wear. Alternatively, the centre line distance between the wheel shafts can be adjusted, or can be made adjustable in length.

The track can be manufactured from equal or unequal angles allowing the top section to be raised or lowered by incorporating slotted bolted holes where required, which in turn can lengthen or shorten the drive chain.

As illustrated in Figure 4, the number of displaceable wheels can vary, and need not be limited to a single wheel as illustrated in Figures 1 and 2.

Referring to Figure 4, the drive chain comprises a number of bogies 30. Between bogies 30 is a displaceable wheel set 31 which comprises a number of pivoting wheels. Again, as illustrated in Figure 4, these wheels adopt a more in-line orientation as they

pass through the vertical turn 32 thereby effectively lengthening the drive chain.

The tracks can be in the horizontal, vertical, inclined or a combination of all three. It should be noted that the cubicles are interconnected with each other in the horizontal or inclined configuration and/or the cubicles can be on top of each other in the vertical or with spaces in between if the extended chain disconnects after only 90° in the wheel to go from horizontal into the vertical and/or from the vertical into the horizontal.

The length of the tracks can be adjusted by increasing or decreasing the distance between the centre line of the wheel shafts. The curved sections before and after the half round curved sections are designed to meet the required shape in relation to the uneven vertical and horizontal distance which occurs when the intermediate wheels between the bogies rise or fall after and before entering in the half circular track. There is no need for extra guidance of the intermediate track but provision for that can be incorporated by extending the wheel shaft and adding an extra wheel on the inside of the track which runs in a U-shaped track section identical to the S-bend connecting the horizontal track section to the half circular track section.

The displaceable wheels can touch or freewheel in the horizontal sections as the bogies are hard up against each other. In cases where the track is of tubular construction the concave wheel track must be deep enough to allow some movement, and in cases where the tracks are in the horizontal and parallel to the surface such as in the plate conveyor system applications the extra wheel can be fitted to the extended intermediate wheel shaft to ensure wheel engagement at all times.

The design allows for the wheel bogie length to be of different size to suit the applications in relation to the cubicle width and height. For example, if the

cubicles in a horizontal system are 2500mm wide and 2200mm high, the wheel bogies can be 625mm long but in a vertical system with the same cubicle dimensions it may be better to make the wheel bogies 550mm and increase the intermediate wheel connecting arms so that the cubicles can rest on each other in the vertical while the shaft pick-up points remain at 45° for the same diameter drive wheels.

Accordingly, various combinations in bogie, connecting arm length, wheel diameter and pick-up points in the drive wheels are possible as long as the extended chain pick-up points and distance apart can be equally divided in the circumference of the drive wheels.

In the vertical as well as in very wide horizontal applications, a sprocket chain to lift the cubicles or move a large number of cubicles in the horizontal can be incorporated to take the strain on the special chain. The sprocket wheels should have a diameter which is identical to the speed ratio in the drive wheels and the cubicle speed in the vertical or the horizontal as the case may be.

In vertical applications (see Figure 5) , the bottom drive wheels are connected to each other by a common drive shaft to ensure synchronism of both special chains and sprocket wheels. The sprocket chains connect to the bogie shaft or special rack assembly fitted to the bogie shaft assembly. The vertical application, as illustrated in Figure 5, uses the chain drive modified such that the bogies in the vertical between the centre line cubicle shaft and the next is equal to the height of the cubicles. This make it possible to rest the cubicles on top of each other. This prevent cubicle swing and provides the highest possible density of cubicles. The speed ratio in the vertical is directly related to the ^' diameter of the sheave over which the sprocket chain runs. Wheel diameter 2560 or 180° = 4010mm : 2200 = 1.8227.2560 : by this calculation = 1405mm diameter.

The wheel and the intermediate bogies are 550mm

X 4 = 2200mm cubicle height. The sprocket chain carries the total cubicle weight with the exception of the top and bottom cubicles which are carried by the return wheels. There are a large number of applications of various sizes, in the horizontal, vertical or combinations of both. This includes live storage systems which require quick loading and retrieval as used in food distribution centres. Aircraft freight containers or shipping containers which can be engaged and disengaged within the systems which in principal use the same drive systems incorporating the special chains to obtain the highest possible density. The two or more wheel drive systems either side keep the cubicles in the long direction in the horizontal position at all times.

It is also possible for the special chain to engage only 90° in the drive wheel from the horizontal track with the cubicles interlocked to the vertical with cubicles connected to the extended chain with space between the cubicles if the height of the cubicles is less than the width or vice versa. This increases the applications where cars are loaded into the system in the bottom row and leave a large opening for roads or rail lines to go through. Referring to Figure 6 - 8, one or more and preferably each of the cubicles are fitted with a movable platform to allow the contents of the cubicle to be pushed out of the cubicle or pulled into the cubicle. The movable platform is in the form of a transfer trolley 41 which in Figures 6 and 7 comprises a platform on which a car can be driven. The platform can be pushed out of the cubicle or pulled into the cubicle to allow the car to be removed from or placed into the cubicle without having to drive the car. The transfer trolley system has particular application in automatic and/or computer controlled electro-mechanical storage or carparking systems using conjunction with a racking or fixed floor storage system. The transfer trolleys can carry goods or

cars in a mechanical storage system or carparking system which can also be used as a lift system to transfer the goods or cars to a fixed storage area.

The transfer trolley 41 is secured in each cubicle and this can be achieved by wheel stops, props, or locking pins which can be engaged or disengaged as required when the transfer trolley is moved forward or backwards. This allows the transfer trolley to be pulled out or pushed into the cubicle on demand either by remote control or by computer software signals.

Figure 8 illustrates a preferred system to allow the trolleys to be removed or inserted into the cubicles. Referring to Figure 8, the illustrated cubicle 10 has a front inlet 42 into which a car or goods can be inserted. At the bottom of cubicle 10 is a transfer trolley 41 which in this instance is formed from a pair of spaced apart car tracks 43 which are supported by a plurality of rollers or castor wheels 44 to allow the entire trolley to be wheeled in and out of the cubicle. In front of inlet 42 is a push/pull assembly 45 which is connected to one or more cables 46 which run over motor 49 driven sheaves. The assemblies control the automatic engagement when no force is applied in either direction and the reverse or disengagement if and when pressure in either direction is applied. The distance of travel and the speed in either direction is controlled by electronic senses or limit switches. Pull/push assembly 45 can move between a forward position shown by reference numeral 47 where assembly 45 is immediately adjacent inlet 42 and immediately behind sheaves 48. In this position, assembly 45 can couple with the transfer trolley 41 inside cubicle 10. Assembly 45 is then reversed to the position illustrated in Figure 8 which in turn pulls the trolley 41 out of its cubicle. By reversing assembly 45, the trolley 41 can be pushed back into cubicle 10 or an adjacent empty cubicle which does not have a transfer trolley 41 and which is now been positioned in place. Push/pull assembly is driven by motor 49.

Figures 9 and 10 show an alternative platform arrangement comprising a transfer conveyor assembly 50 having two built-in reversible driving motors 51, 52, one to drive one set of the support wheels and the other to drive the conveyor assembly itself. The driving motors 51, 52 remain on cubicle 10 and function to push out the transfer trolley 41 (Figure 10 showing the transfer trolley in the extended position and Figure 9 showing the transfer trolley in the retracted position) . Referring to Figure 11, there is shown a car on a horizontal floor parking system where guide rollers can be used instead of drive wheels on each side of the wheels in the centre which eliminates the need for tracks to keep the shifting plates on which the cars are parked in line. The carrying plates are fitted with self- steering wheels forming part of this application. The height of the system is important especially when the system is to be installed on the top of existing concrete floors. To limit this to the minimum requirement, the special chain is also turned in the horizontal plane which is made possible by the use of nylon or similar wheels which run on tubes.

The transfer systems can be used in both vertical or horizontal mechanical storage systems in combination with racking and/or fixed floor storage arrangements by which the transfer trolleys can be recovered empty for re-use or where the trolleys remain in the system at all times loaded or empty in which case the trolley can remain in the container or cubicle or is stored in a fixed position for part of the time. In the case of parking systems, the use of the transfer trolleys can, for example, be limited to long or longer time parking above a set time limit. The container/cubicle floor can be flat or incorporate wheel tracks for cars ^' and/or trolleys. It is also feasible to fit the trolleys with special supports to enable the storage of paletted goods or, for example, bikes or motorbikes or other special goods etc.

The advantages of the transfer trolley systems as described is the increased capacity of a mechanical storage system while maintaining the density at a lower cost than the mechanical system itself. The loading times remain more or less the same but the transfer of trolleys out and in the movable containers or cubicles increases the retrieval times by a factor of 2 which is still much better than for racking or pigeon hole systems serviced by O.H.T. cranes, mast forklift-type systems and/or systems which require the return of the empty loading pallet each time goods or a car is stored or parked in a stationary position.

In an effort to make the mechanical carpark more attractive in certain circumstances, a separate trolley can be designed which is supported by small wheels which fits neatly in a cubicle with the wheel tracks being 500mm wide instead of 400mm wide.

The trolley will remain in the system and can be used to park cars in fixed spaces of racking systems or suspended floors adjacent to the system on one or both sides.

The system can now be used as a car lift as well as a mechanical car parking system at the same time. The parking in the fixed spaces can be offered, for example, at a special rate for long or longer term parking.

The basic theory behind it is that there will be a trolley for each fixed space available in the system. There are less fixed spaces because a four high system has always a minimum of 6 drive wheels in the vertical curves behind which we cannot park and in most cases at least one loading level must have +/- 6m in front of the cubicles for access.

There is no reason why a cubicle with a trolley cannot be used for short term parking by not removing the trolley from the cubicle.

The removal of the trolley with a car parked on it on to a fixed space is done via the computer program

automatically.

The drawing shows a system with a transfer unit fitted with a special engagement attachment fitted to a rope and pulley system which pulls out the trolley and car and on command, pushes the trolley back into the cubicle after which the system delivers same to the point where the user has inserted his ticket or credit card.

Customers wanting long term parking are directed to cubicles with a trolley. The driver positions his car in line with the magnetic card reader and must press "L" for long term parking before inserting his ticket or credit card.

Assuming that the unit is stationary, the boom gate will rise and the car must be parked on the trolley. The driver walks out of the cubicle and the boom gate closes. The computer program will bring this cubicle to the nearest available long term parking spot. The cubicle stops within 20mm of the centre line. The transfer unit moves forward and engages the trolley before moving backward pulling the trolley into the vacant spot.

The moment it starts pulling, the locking pins disengage and the trolley moves out and stops clear of the cubicle and the locking pins engage in the fixed floor space. Then the car is recalled, the same sequences takes place in reverse.

There are other methods to pull and push the loaded trolley out and into the cubicle. The preferred method is by using a track mounted engagement unit which has a built-in drive motor in one of the driven drums, the same as used in conveyor systems in other words and of the shelved item

The unit can be battery powered or fitted with a save trailing cable because the distance this assembly moves in is maximum only 1.5 metres.

Again the transfer unit disengages and engages the locking pins automatically by mechanical means . One set is fitted to the cubicle itself and the other at the

end of the fixed parking space to ensure that the trolley cannot move while parked in the cubicle or in the fixed parking space.