GB2185457A

GB2185457A - Material handling apparatus

Info

Publication number: GB2185457A
Application number: GB08700930A
Authority: GB
Inventors: John Maurice Van Den Bergh
Original assignee: MARRYAT HANDLING SYSTEMS LIMIT
Current assignee: MARRYAT HANDLING SYSTEMS LIMIT
Priority date: 1986-01-16
Filing date: 1987-01-16
Publication date: 1987-07-22
Also published as: GB8700930D0

Abstract

Conveying apparatus, e.g. for conveying foodstuff packages 10 through a cold store 1, comprises several floors arranged one above the other, with each floor being defined by parallel walking beam or multiple-pusher conveyors for conveying the packages in mutually spaced relationship and in stepwise manner. The conveyors in each floor are operated in unison so that transverse rows of packages are advanced together along the conveyors. The conveyors also serve to take packages from a loading beam 14 and to deliver packages to a discharge beam (not shown), the loading and discharge beams being movable vertically to co-operate with the conveyors of each flow. The conveyors may be powered by means carried on the loading and/or discharge beams. <IMAGE>

Description

SPECIFICATION Material handling apparatus This invention relates to apparatus for handling materials and in particular for conveying articles, such as items or portions or foodstuff, through a storage or treatment space.

As specifically described herein the invention is embodied in an apparatus for conveying packages of foodstuff through a cold store in whch the foodstuff is subjected to cooling and possibly freezing by cooled air which flows over the packages within the cold store. As will be understood from reading the description which follows, however, the apparatus of the invention may also be suitable for other specific applications.

Various forms of apparatus for conveying articles such as foodstuff packages through a cold store are known. In most mechanisms the packages abut against each other in the direction in which they are advanced, which impedes the circulation of cold air over the individual packages and can result in non-uniform cooling and thereby less than perfect products. Another known device relies upon a reciprocating baffle plate to index the packages along by pushing against successive packages, but during the return stroke the baffle plate slides over the packages and can score them. An alternative method of conveying the packages which avoids this problem is based upon the use of roller conveyers. This solution is expensive, however, and it does have the disadvantage that the successive packages abut against each other.A further known apparatus utilises a spiral conveyor, but this suffers the disadvantages of being expensive, susceptible to damage occurring when the system comes to a halt, and inefficient in the utilisation of space because of its shape. One final form of conveying apparatus known in the prior art incorporates plates on to which the packages are placed and a complicated conveying system advances the plates and packages together. This apparatus, because of the many mechanisms involved, is expensive and liable to breakdown.

The present invention aims at an apparatus which avoids the drawbacks of the prior art systems, and accordingly provides an apparatus comprising a walking beam device operable to convey articles successively and in a stepwise manner along a linear path, said articles remaining spaced apart as they are advanced along the path, and said device being arranged to transfer articles from a loading member at one end of the device and to transfer articles to a discharge member at the other end of the device.

For the purposes of the present specification the term "walking beam device" is defined to mean a conveyor having two sets of parallel rails extending in the direction of the linear path along which the articles are to be conveyed. A drive mechanism is provided whereby one set of rails is moved through a forward stroke to engage and advance the articles, and is then driven through a return stroke while the articles rest on the other set of rails.

In a preferred embodiment of the invention the walking beam device comprises sets of parallel rails forming a plurality of conveyors defining respective parallel linear paths, the articles being advanced along the conveyors in rows extending transversely to the direction of the linear paths, and the walking beam device being arranged to transfer rows of articles from the loading member and to the discharge member. In addition, a plurality 6f floors each having a walking beam device are positioned above one another, and the loading and discharge members are movable to operate with the walking beam device of each floor. The walking beam conveyor device on each floor may be equipped with its own actuating means for driving the movable rails.In an alternative construction, however, the actuating means is mounted on the loading and/or the discharge member for operating the movable rails of the conveyors in each floor when articles are to.be fed to and/or discharged from that floor. In this way the need for separate actuators for each floor is avoided and a significant cost saving can be made, especially when there is a large number of floors in the apparatus.

Each conveyor may conveniently comprise alternate fixed and movable rails. Another arrangement is to have a plurality of fixed rails with two movable rails located either side of the fixed rails. This arrangement has the advantage that adjacent conveyors on the same fllor can share the movable rail which is located between their respective fixed rails, and in this way the number of movable rails required in each floor can be reduced, and the weight to be moved when the conveyors are operated is consequently reduced also. A further advantage is that stop lugs provided on the movable rails for abutting the articles to move them forwards, can be adapted to engage the packages at the corners where they are at their strongest and less liable to deformation by the lugs pressing against them.

The movable rails of the conveyors may be arranged to be driven by raising and moving he rails forward to engage and advance the articles, and then lowering and moving the rails rearwardly through a return stroke while the articles remain resting on the other rails.

With the rails being moved up and down as well as longitudinally then can be fitted with fixed stop lugs. In an alternative embodiment, however, the movable rails are provided with adjustable stops adapted to project for engaging the packages during forward displacement of the rails, and to be moved to an inopera tive position to pass beneath the packages when the rails are displaced rearwardly. By providing adjustable stops the need for the rails themselves to be raised and lowered is eliminated and they need only be reciprocated backwards and forwards. The stops could be retractable with a mechanism for controlling their projection and withdrawal in accordance with the movement of the conveyor rails, but in an especially simple construction, the stops are lugs hinged to the rails to be pivotable between the operative and inoperative positions.The lugs can be biased to the operable position by light springs and be pushed down by the articles themselves when the rails are moved rearwardly.

A more complete understanding of the invention will be had from the following description which is given with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a cold store incorporating an apparatus in accordance with the invention; Figure 2 is a sectional side elevation showing the walking beam device of the conveying apparatus; Figure 3 is a section taken along the line A-A of Fig. 2; Figure 4 is a sketch illustrating schematically the drive mechanism for the walking beam device; Figure 5 is a schematic plan view of part of the conveying apparatus and illustrating a modification; Figure 6 is a side view of the apparatus in Fig. 5; and Figures 7 and 8 are side views showing a movable rail having pivoted stop lugs.

The cold store illustrated in Fig. 1 encloses a cooling/freezing chamber or cold store 1, the walls of which have been shown partly cut away to reveal the conveying apparatus of -the invention which is housed within the store 1. A. refrigeration plant (not shown) is provided for circulating cold air within the chamber. Articles, such as containers or packages 10 of foodstuff to pass through the cold store enter the chamber through an opening in the side wall and are immediately accelerated forwards on a roller conveyor 8 to ensure that the successive packages 10 are spaced apart on the conveyor 8. The packages are collected on the conveyor 8 into two groups or rows each containing.e.g. nine packages. The conveyor 8 is equipped with sensors and stops which rise up behind the packages to ensure that the packages in each row are correctly spaced apart.Mounted alongside the conveyor 8 is a pushing device 12 which is operable to push the rows of packages forwardly off of the conveyor 8- for delivering them to the main conveying system for carrying the packages through the cold store. This system is divided into two lateral sections which are located side-by-side, and each section includes several floors or tiers, there being eight as depicted in the drawing. The floors are defined by walking beam conveyers, as described in more detail below with reference to Figs. 2 to 4. A loading mechanism is provided for delivering the rows of packages to the respective floors and includes a horizontal transfer beam 14 guided for movement withi na vertical plane by a frame comprising two uprights 16 connected by a crossbeam 18.In its lowermost position the transfer beam 14 is located adjacent the conveyor 8 for receiving the rows of packages when they are pushed off of the conveyor 8 by the pushing device 12. The transfer beam may then be moved upwardly to position the packages carried thereon ready to be picked up by the walking beam conveyers of any one of the floors.

Provided at the end of the conveyor system opposite the loading mechanism is a discharge mechanism (not shown in Fig. 1). The discharge mechanism is of essentially the same construction as the loading mechanism, and consists of a horizontal transfer beam 15 (Fig.

2) extending transversely to the walking beam converyors and guided for movement vertically between a pair of upright members of a guide frame. The transfer beam 15 is positionable to receive rows of packages from any one of the conveyor floors and to carry them down to a discharge station at which a pushing device of substantially the same form as the device 12 is disposed for pushing the packages off of the transfer beam 1 5 and onto a power roller conveyor system 7 which transports the packages back through and eventually out of the cold store 1.

Referring now to Figs. 2 and 3, each walking beam converyor comprises three parallel longitudinal rails 20, 21, 22 extending in the direction in which the packages are to be conducted, and stationarily supported by fixed transverse beams 23. Located intermediate the fixed rails are two rails 25, 26 which are movable both vertically and longitudinally relative to the fixed rails. The movable rails 25, 26 are connected to each 6ther and to the movable rails of the other conveyers on the same floor by transverse members 27. As may be seen in Figs. 2 and 3, the movable rails 25 are equipped with upstanding stops or lugs 28 for abutment with the rear faces of the respective packages for moving them along the fixed rails and ensuring that they remain spaced apart at the correct distances.

The drive mechanism for the movable rails is shown schematically in Fig. 4. The movable rails are supported by rollers 30 on pivoted arms 31. A first, lifting hydraulic cylinder 32 is coupled to the arms 31 for pivoting the arms to raise and lower the rails 25, 26, and a second, stroke hydraulic cylinder 33 is coupled to the rails for reciprocating them longitudinally through forward and return strokes. To transport the packages on the conveyor through one advancing step, the stroke cylinder 33 first displaces the rails 25, 26 through a rearward stroke and then the lifting cylinder 32 is actuated to raise the rails 25, 26 thereby lifting the stops 28 to project above the fixed rails 20-22 between the packages.The stroke cylinder 33 is then actuated to move the rails 25, 26 forwardly, the stops 28 engaging and carrying the packages 10 with them so that each package progresses forwards one step. The rails 25, 26 are then lowered and returned to their initial position ready for the next advancing step.

It will be appreciated that the walking beam conveyors in each floor operated in unison so that the rows of packages on each floor advance together. In the particular conveyor system shown in the drawings there are nine walking beam conveyors in either section on ech floor, each conveyor serving to transport a single line of successive packages, and the packages on the respective conveyors being aligned in transverse rows.

It is an important aspect of the apparatus of the invention that the walking beam conveyors also operate to take the packages off of the transfer beam 14 of the loading mechanism and to deliver them onto the transfer beam 15 of the discharge mechanism. This feature is best illustrated in Fig. 2. Each transfer beam 14, 15, has a supporting platform defined by spaced parallel bars or slats 35 mounted on a supporting member 36. Thus, the beams 14, 15 have a comb-like structure. The bars 35 are arranged to align with the fixed rails 20-22 of the walking beam conveyors, whereby the moving rails 25, 26, can move within the gaps between the bars 35.

When the walking beam conveyors on any floor are operated to advance the packages thereon, in the manner explained above, on the initial reward stroke of the rails 25, 26, the trailing ends of these rails pass between the bars 35 of the transfer beam 14. Upon the subsequent raising and forward movement of the rails 25, 26, the packages on the beam 14 are drawn off of the beam and carried forward onto the walking beam conveyors, the packages thereby being moved from the position 10' to the position 102 as seen in Fig. 2.

Similarly, the abutment stops 28 on the loading ends of the rails 25, 26 engage behind the packages in the front row on the conveyors and push these packages off the ends of the rails 20-22 and onto the adjacent transfer beam 15 waiting to receive them. Thus, these packages are moved from position 103 to position 104.

For the most part the operation of the apparatus for conveying the packages through the cold store will be understood from the foregoing description, but it will now be explained briefly in the inerest of clarity. When the two rows of packages have been collected on the converyor 8, the device 12 is actuated to push the packages onto the transfer beam 14 previously positioned alongside the conveyor 8. The transfer beam 14 is driven upwardly to a position adjacent a pre-selected conveyor floor, e.g. the top floor, and the walking beam conveyors of this floor are operated to draw the packages off of the transfer beam 14 and onto the conveyors. The transfer beam is returned ready to receive the next rows of packages from the conveyor 8. This process is repeated until all the converyor floors are filled with packages and can conveniently be achieved by filling the floors in turn.The next two rows of packages to enter the conveyor system are delivered to the uppermost floor and the walking beam conveyors of this floor are actuated to advance the existing packages in that floor, at the same time taking in the packages from the transfer beam 14 of the loading mechanism and delivering the front row of packages onto the transfer beam 15 of the discharge mechanism. The beam 15 is lowered and the packages carried on it are pushed onto the conveyor system 7 to be conducted out of the cold store. Thus, as rows of packages are entering the conveyor system others leave, with the first to arrive being the first to leave.

The described walking beam conveying apparatus for conducting packages through a cold store avoids the problems suffered by the prior art conveyors. The packages are maintained spaced apart to enable free circulation of cooling air over their surfaces, including the bottom surfaces with the packages being carried on spaced rails. At the same time positive transport of the packages is ensured throughout the length of the store. Furthermore, the construction is uncomplicated, the loading and discharging mechanisms being particularly simple, so that the apparatus is economic to manufacture and reliable in operation.

Modifications are, of course, possible to the described apparatus without departing from the inventive principles. For example, the number of conveyor floors may be varied according to requirements, as may the number of walking beam conveyors on each floor. As described the moving beams of the walking conveyor are arranged to advance the packages by sliding them along the fixed rails by use of the stops 28. It would also be posible for the drive mechanism to be arranged to lift the packages off the fixed rails, preferably after the stops have been engaged against them, for freeing the packages from the fixed rails in case they have become frozen or otherwise stuck to them. Other modifications are described below referring to Figs. 5 to 8.

Fig. 5 represents one floor of the conveying apparatus, much detail having been omitted. In each floor of the conveying apparatus the walking beam conveyors have fixed rails (not shown) located between movable rails connected to the two laterally outermost rails 125, 126 shown in Fig. 5. Adjacent conveyors share a common movable rail which is located between their respective fixed rails, rail 127 being such a common rail. At each end the rails 125, 126 are provided with laterally protruding lugs defining channels 150.

The transfer beam 114 of the loading mechanism carries linear actuators 152, 153 located one at each end of the beam. Similarly, the transfer beam 115 of the discharge mechanism carries linear actuators 154, 155 at its ends. Carried by each actuator 152-155 is a driving arm 160 having an inturned end, the arm being reciprocable in the longitudinal direction of the conveyors by the respective actuator, e.g. between the forward positions shown in full line and the rearmost positions shown in broken line for the actuators 152, 153.

When packages 110 are to be fed to and discharged from the conveyors at any particular floor of the conveying apparatus the transfer beam 14, carrying the packages to be loaded, and the transfer beam 15 are moved vertically to the level of that floor and the driving arms 160 are automatically located in driving cooperation with the channels 150 on the arm 125, 126. The linear actuators are then operated to reciprocate, first backwards and then forwards the moving rails of the conveyors to take the packages from the transfer beam 14 and deliver packages on to the transfer beam 15. At the same time packages already on the conveyors are advanced by one step. During this reciprocation the movable beams may be raised and lowered as in the embodiment of Figs 1 to 4.Alternatively, the stop lugs 128 provided on the movable rails may be adjustable, moving downwardly during the return stroke of the rails to pass beneath the packages and projecting upwardly to abut the packages when the rails are driven through a forward stroke (see Figs. 7 and 8 described below).

By providing actuators 152-155 on both the loading and unloading mechanisms, the floors of the conveyor can be loaded and emptied independently. Thus the loading mechanism may load packages on to a previously emptied floor, while the unloading mechanism removes them from a full floor, such a mode of operation being depicted in Fig. 6.

The linear actuators 152-155 may be fluid operated devices. Alternatively they may comprise electro-mechanical devices, e.g. lead screw mechanisms, in which case each pair of actuators 152, 153 and 154, 155 can be operated by a common drive motor and be coupled by a shaft to ensure accurate longitudinal movement of the walking beam rails 125, 126. The use of an electro-mechanical actuating system also has the advantage of eliminating the need for high pressure hydraulic devices and pipework, which is preferable for an installation intended to handle foodstuff.

For the same reason it may be preferable to use an electro-mechanical actuator instead of a fluid actuator for raising and lowering the movable rails if they are to be moved in this way.

From the foregoing description it will be apparent that the use of actuators mounted on the loading/unloading mechanisms reduces the number of actuators required. In particular just two pairs of actuators are needed for effecting reciprocation of the walking beam rails of all the floors included in the apparatus.

Figs. 7 and 8 are side views showing a movable rail of a walking beam conveyor having stops 128 pivoted thereon.The stops are counterweighted so that they are biased to project upwardly from the rail as seen in Fig.

7, and during forward displacement of the rail (to the right as seen in Fig. 7) the stops engage the packages 110 to move them along with the rail. Fixed abutments 129 limit the pivoting movement of the stops in this position. When the rails are displaced in the opposite direction, the stops 128 are free to pivot down against the bias of their counterweights and pass beneath the packages, as in Fig. 8.

In the apparatus of Fig. 1, during each loading operation the transfer beam 14 must travel to the loading station in order to collect a row of packages. Similarly, the transfer beam 15 has to travel to the discharge station during each unloading operation. As a result the loading/unloading rates may be limited. To enable faster operation the input conveyor 8 and the pushing device 12 may be mounted on the transfer beam 14 to move up and down with it, whereby rows of packages can be loaded onto the beam whatever its position.

An outfeed conveyor and pushing device may be mounted on the discharge transfer beam, enabling rows of packages to be unloaded from the beam 15 in any position of the beam. In case of such modification each of the ineed and outfeed conveyors will have a pivotted conveyor attached and arranged so that its inclination will vary as the transfer beam moes up and down, the pivotted conveyors allowing packages to be carried to and from the infeed and outfeed conveyors, respectively, from and to ground level.

Claims

1. An apparatus for conveying articles in mutually spaced relationship through a storage and/or treatment zone, comprising a walking beam device (as herein defined) operable to convey articles successively and in a stepwise manner along a linear path, said articles remaining spaced apart as they are advanced along the path, and said device being arranged to transfer articles from a loading member at one end of the device and to transfer articles to a discharge member at the other end of the device.

2. An apparatus according to claim 1, wherein the walking beam device comprises sets of parallel rails forming a plurality of conveyors defining respective parallel linear paths for articles to be advanced therelaong in rows extending transversely to the direction of said linear paths, and said device being arranged to transfer rows of articles from the loading member and to the discharge member.

3. An apparatus according to claim 2, wherein a plurality of floors each having a walking beam device are positioned above one another, and the loading and discharge members are movable for transferring articles to and from each floor.

4. An apparatus according to claim 3, wherein each loading and discharge member comprises a transfer beam for receiving a row of articles, the beam being guided in a frame for vertical movement between the floors.

5. An apparatus according to claim 4, wherein each transfer beam comprises a support surface defined by elements spaced apart along the beam to enable moving rails of the walking beam devices to move between said elements.

6. An apparatus according to claim 5, wherein said elements comprise slats arranged to align longitudinally with stationary rails of the walking beam devices.

7. An apparatus according to claim 4, 5 or 6, wherein the loading transfer beam is movable to an article receiving station, means being provided at said station for collecting a row of articles and delivering said row on to the transfer beam.

8. An apparatus according to any one of claims 4 to 7, wherein the discharge transfer beam is movable to a discharge station, means being provided at said discharge station for removing a row of articles from the beam.

9. An apparatus according to any one of claims 3 to 8, wherein actuating means for driving the movable rails of the walking beam devices are carried by the loading and/or by the discharge member, said actuating means being arranged to drive only the walking beam device of the floor at which said member carrying the actuating means is positioned.

10. An apparatus according to any one of claims 2 to 9, wherein each of the walking beam device conveyors includes a plurality of fixed rails, and two movable rails located on either side of the fixed rails, adjacent conveyors sharing a common movable rail located between the fixed rails of the respective conveyors.

11. An apparatus according to any one of the preceding claims, wherein movable rails of the or each walking beam device are provided with stops for engaging the articles when advancing said articles.

12. An apparatus according to claim 11, wherein the stops have an operative position for engaging the articles during a forward stroke of the movable rails, and said stops are adjustable to an inoperative position to pass beneath the articles during a rearward stroke of the movable rails.

13. An apparatus according to claim 11, wherein the stops are pivoted to the rails for movement between the operative and inoperative positions, and are biased to the operative position.

14. An apparatus according to any one of claims 1 to 11, wherein the movable rails of the or each walking beam device are arranged to be driven by raising and moving said rails forward to engage and advance the articles, and then lowering and moving the rails rearwardly through a return stroke while the articles remain resting on the other rails.

15. An apparatus according to claim 14, wherein first actuating means are provided for raising and lowering the movable rails and second actuating means are provided for reciprocating said rails longitudinally.