CA2184774A1 - Apparatus for stacking layers on a pallet, and a palletizing system - Google Patents

Abstract

The present invention relates to apparatus for stacking layers on a pallet and to a palletizing system including such layer-stacking apparatus. The invention provides apparatus that is flexible and reconfigurable in real time for making up layers and/or apparatus that is flexible and/or reconfigurable in real time for stacking layers on one or more pallets that are being built up.
The flexible apparatus for making up layers comprises, for example, a programmable moving-arm robot fitted with batch-grasping means, a conveyor for continuously feeding it with sales items, and a wide conveyor for taking layers away to layer-stacking means. The present invention is mainly applicable to handling, storing, and transporting products coming from a flexible production line.

Description

21~774 APPARATUS FOR STACKING LAYERS ON A PALLET, AND A
PALLETIZING SYSTEM
The present invention relates to apparatus for stacking layers on a pallet and to a palletizing system 5 inrl~l-l;n~ such a~ClLc-~us for stacking layers.
Palletization can be peL~ 1 flexibly, but only at very low rates, when using known techniques. Normally, if palletization is ~ Lf~ 'i manually, it is po~q1hl~ to build up pallets that are non-uniform and/or that are 10 i~ te. However, this gives rise to relatively high costs, to palletization schemes that are not very ~ffi~ nt, and consequently to pallets whose stability cannot always be guaranteed. Also known are palletizing r~-h;n~ capable of operating at high rates and that are 15 well adapted to making up long series of pallets that are identical and uniform.
However, in the mass-marketing industry, in particular in the f arm-produce industry, there is a trend towards diversifying items on sale, i . e. towards 20 diversification of the goods and of the r~.k~; n~ on offer to customers. In addition, distrlbutors try to mlnimize stock and conse~uently they order the exact number desired of any particular sales item, even if that number does not necessarily correspond to a whole number 25 of complete and uniform pallets.
Consequently, the object of the present invention is to provide means for palletizing a wide variety of individual sales items that are grouped together in various ways on different pallets, and to do so at a high 30 rate.
Another object of the present invention is to provide means for building up non-uniform pallets at a high rate, each pallet carrying various types of individual sales item that may optionally be organized in 35 uniform layers.
Another ob~ ect of the present invention ls to provide means ~nFlhl ;n~ incomplete pallets to be built up.

218~77~

Another object of the present invention is to provide means Pn;~hl ing pallets corrPqpt~n~lln~ to a plurality of palletization schemes to be built up simultaneously or as alternatives.
Another object of the present invention ls to provide palletization means that occupy little ground space .
Another ob~ect of the present invention is to lose practically no production time during changeovers when switching pallet b~ i n~ between sales items of di f f erent kinds .
Another ob~ ect of the present invention is to provide palletization means operating at a rate that can adapt to the output rate of a production and/or pA--k~1 line.
According to the invention, these ob~ects are achieved by; ,1~ Llng apparatus that is flexible and reconfigurable in real time for making up layers and/or d~ Lus that is flp~lhle and/or reconfigurable in real time for stacking layers on one or more pallets that are being built up. The flP~lhle layer forming apparatus comprises, for example, a proul hl P moving-arm robot provided with batch grasping means, a UUI~V~:yuL for continuously feeding sales items, and a broad ~:UllVt~yUl for taking layers away towards the layer-stacking means.
The layer-stacking apparatus of the invention comprises, for example, a plurality of layer shapers associated with a robot having three Cartesian axes X, Y, and Z, provided with means for grasping complete layers and for depositing a layer on a preceding layer of a pallet that is being built up.
If so desired, 1~;.1 ~Ing a flexlble system makes it pr)e.ql hl P to ~ Inl r;~te pertinent information about the constitution of the layers or of the stack of layers on pallets to the various robots in the system of the present invention. For example, the following information may be communicated to the robots for making 218~774 up layers: the geometrical characteristics of batches;
the identities of individual batches corresponding to the various layers that are to be made up; whether or not certain sales items are fragile; the palletization scheme to be adopted; the batch grasping tool(s) to be used; the orientation of the sales items arriving on the ~ :UIlV~:yOl;
etc .
The layer-stacking robot receives information about the various layers to be stacked, about the various uniform or non-uniform pallets to be built up, the geometrical characteristics of the various layers, the layer-grasping tool(s) to be lr~rl, ted, the need for spacers to be inserted, where d~Lu~llate, between successive layers on pallets that are being built up, the fragility of layers, the locations where pallets need to be built up, etc.
Carts for automatically transferring pallets that are being built up and/or palletized loads receive informatlon r.rnrl~rn~ n~ the location of a pallet to be taken away, the location to which the pallet is to be taken, the best path to follow between the location from which to take the pallet being built up or the completed palletized load, and the location to which to take the pallet being built up or the completed palletized load, the type of pallet to be handled, possible fragility of the pallet being built up or of the palletized load to be transferred, etc.
This information can be downloaded to the proyl hl e controllers all at once, or advantageously as and when it becomes pertinent, from a computer system for Fl~nnln~ production and/or managing throughput. In a variant, a central, _ Ui,~l having said information avallable to it lssues ~ lq directly to the varlous apparatuses of the invention.
The present invention provides a robot for stacking layers of individual sales items on a pallet, in 21847~
application of a palletizing scheme, the robot comprising:
a) apparatus for feeding layers to be stacked;
b ) means for grasping the layers;
c) at least two locations for receiving pallets that are being built up;
d) control means, and in particular a proyl hlP
controller; and e) drive and guide means for driving and guiding the means for grasping layers, in response to a command received from the control means, to deposit the layer grasped by the layer-grasping means on a preceding layer of a pallet that is being built up, or on the pallet itself if the layer grasped by the means for grasping layers is to become the first layer of a palletized load, which pallet i8 (li qpOqP~ in any one of said at least two pallet-receiving locations.
The invention also provides a robot, characterized in that said robot ls a Cartesian gantry robot having three UL ~lloyullal axes.
The invention also provides a robot, characterized in that means for grasping layers comprise a platform having its bottom constituted by a curtain, and in that the platform includes an openlng for being loaded laterally with layers.
The invention also provides a robot, characterized ln that the means for grasping layers include shaper means for ensuring r.nhP.ql r~n of the layer that is being deposited on the pallet that is being built up.
The invention also provides a robot, characterized in that the device for feeding layers to be stacked comprises a conveyor whose width is substantially equal to and preferably slightly greater than the width of the layers suitable for being grasped by the means for grasping layers.
The invention also provides a palletization system characterized in that it includes a robot of the , .

invention and at least one robot for making up layers on a device for feeding layers to the layer-stacking robot.
The invention also provides a system, characterized in that the robot for making up layers includes a moving arm, and in that sald system includes at least one UUllV~yuL for feeding loads to the robot for making up layers .
The invention also provides a system, chc~ L~ lzed in that it f nm.l IlliP':: two robots for making up layers, said robots being (~f cpm~P~ ~y Lllcally on either side of the device for feeding layers to be stacked to the robot for stacking layers.
The invention also provides a system, characterized in that the robot(s) for making up layers include(s) means for automatically mh;ln~f n~ batch-grasping tools.
The invention also provides a high rate palletization facility characterized in that it includes a plurality of palletization systems of the invention ~1~ cpQ~:P~f in parallel together with means for feeding at least two of said palletization systems with sales items.
The invention also provides a palletization method, characterized in that it i mrl, ts a system of the invention .
The invention also provides a method of building up non-uniform pallets comprising a plurality of types of layers in a stack, the method being characterized in that it comprises the steps consisting in:
a) loading into a ~ ~ U~ l system a scheme for stacking the layers of a non-uniform pallet;
b ) depositing the fir~t layer( s ) of the pallet by means of a layer-stacking apparatus;
c ) using an automatic cart under the control of said computer system to remove from the layer-stacking apparatus the pallet which is being built up, in order to wait for layer-stacking apparatus to become available for stacking layers of another type that are to be stacked on the non-uniform pallet;

218477~

d ) taking the pallet that is being built up to the layer-stacking apparatus having layers that are to be stacked on the non-uniform pallet that is being built up;
e) repeating steps c) and d) until the non-uniform pallet has been completely built up; and f ) removing the completed non-uniform pallet from the layer-stacking a~dLa~us.
The invention also provides a method, characterized in that during step c ), the pallet which is being built up is removed to a dynamic storage ~one, and in that during step d ), the pallet being built up is taken from the dynamic storage zone and brought to the layer-stacking a~yaL atUS .
The invention will be better understood from the following description and the ~l -nying figures given as non-limiting ~ ,1 PR, and in which:
Figure 1 is a plan view of the preferred embodiment of aL~ala~us of the present invention for making up layers;
Figure 2 shows one example of layers made up by the Figure 1 apparatus;
Figure 3 is a flow chart for a layer make-up ~Tnr;q ~ ~n;
Figure 4 is a perspective view of the preferred embodiment of apparatus of the present invention for stacking layers;
Figure 5 is a plan view of a layer-grasping device in the layer-stacking apparatus of Figure 4;
Figure 6 is a vertical section on VI-VI through the Figure 5 device;
Figure 7 is a flow chart PYr1~tn1n~ how layers are deposited in accordance with the invention;
Figure 8 is a diagrammatic plan view of an embodiment of a palleti2:ation system of the present invention;
Figure 9 is a flow chart .oYrl~ntn~ the operation of the palletization system of the present invention;

Figure 10 is a plan view of a battery of Figure 8 palletization system rl1 epr~Ptl at the outlet of a production line; and Figure 11 is a plan view of a flexible 5 palletization workshop of the present invention.
In Figures 1 to 11, the same references are used to designate the same ~1 l Ls.
Figure 1 shows C~)~CIL 0, Lus of the present invention for building up layers, the apparatus comprising at least 10 one and advantA~o~lcly two robots 1 each having a moving arm 3 provided with grasping means for grasping individual sales items 5 constituting batches 6 to be palletized and travelling in the direction of arrow 7 on a UUIlV~yul 9 that is preferably a low thrust ~;UIlV~yuL.
15 The ~:UIlV~:yUl 9 is of sufficient width to transport any individual sales item 5 that is to be palletized by means of the apparatus of the present invention. A conveyor 11 for receiving and making up layers travels in the direction of arrow 13 and is of a width L greater than 20 the width of the ~ lV~yUl 9, the width L being substantially equal to and preferably slightly greater than the width L ' of the largest layers 15 that the apparatus of the present lnvention is to make up. In the example shown, the apparatus comprises two robots 1 25 disposed facing each other on opposite sides of the ~:UllV~yUl 11 for receiving layers 15, and each associated with a respective UUI~vt:yul 9 for feeding individual sales items 5. Under such cil~ Lc-llces, the lefthand robot makes up the left half of each layer while the righthand 30 robot makes up the right half of each layer. This serves not only to double the rate at which layers are made up in comparison with using a single robot, but also offers the poc~; h~ 1 i ty of using two robots 1 each provided with an arm 3 of reach that is smaller than the width L of the 35 UUIlVl:yul 11. Naturally, it would not go beyond the ambit of the present invention to use a single robot or to use several robots all disposed on the same side, or better 218477~

on both sides of the UUIlV~:yUL 11 for receiving layers.
Adv~llLc,~eously, moving-arm robots 1 are used that have four degrees of freedom, for example A520i robots manurcluLul~d by FANUC. Nevertheless, it is possible within the ambit of the present invention to 1 l ~ L
other types of robot, e.g. robots mounted on a gantry.
In the ~ 1 t shown in Figure 1, each robot 1 is disposed between the UOIlV~yUL 11 for receiving layers 15 and a respective ~UIlVUyUl 9 for feeding sales items.
Advantageously, each UUIlV~yul 9 for feeding individual sales items 5 terminates in a magazine 17 for receiving any items that are not picked of f by the robots 1, with such a magazine serving in particular to store any individual sales items that are not acceptable, e. g.
items that are damaged, in particular that are broken or wrongly positioned. In a variant, shown in Figures 8 and 10, the UOIlv~:yul~ 9 and 11 are juxtaposed, with the robots 1 being disposed at the end of the UUIlVt:yuL 9, thereby ~nz~hl i n~ the reach of each arm 3 to be reduced for placing batches of sales items on the UUIlVt:yuL 11 for receiving and b~ i n~ up layers . It should be observed that apparatus of the invention makes it possible not only to build up layers that are uniform, but also to build up layers that are not uniform, comprising several types of sales item 5, preferably all having the same height .
In a variant that is not shown, the UUIlVt:yul i 9 are closed circuit UUIlV~yul~i fed with various types of sales item 5, continuously and/or on demand, e.g. from a pA--k;:~1 n~ or production line. Each UUllV~yuL 9 can serve one or more robots 1. Each robot 1 identifies sales items 5 travelling on the UUIlV~yul 9 and it picks off the batches 6 that it requires for making up a requested layer 15.
In a first variant ~ tlir-~t, the Uullv~yul for receiving and making up layers 11 is stationary while a layer is being made up by the robots 1.

g In an advantageous variant, the UUIlVt!yul 1 for receiving and making up layers moves at constant speed.
The coordinates at which the various batches making up each layer are deposlted keep track of the motion of the ~UIlV~yul 11. The posltion where a batch is deposited on the UUIlV~yul 11 is, , _I ~d by the robot 1 on the basis of the position of the batch within the layer and the position of the layer on the UUIlV~:yul 11 at the moment the batch is deposited. Advantageously, acquisition means, in particular photoelectric cells, ultrasound detectors, or an ar~ vision system disposed above the u UIlV~yUl 11, serve to verify the real position of the layer 15 . An example of a layer being made up 15 ' is shown in dashed lines in Figure 1. Advantageously, the robots 1 begin by making up downstream rows of the layer.
In Figure 2, there can be seen an example of a layer 15 that has been made up by the apparatus of Figure 1.
Batches Al to A18 were deposited by the robot 1 on the left of the ~:UllV~yUl 11 in Figure 1. Batches Bl to B18 were deposited by the robot 1 located on the right of the UUIlV~yul 11 in Figure 1. It should be observed that the batches deposited by the lefthand robot are not n~ q~ ~rily disposed in exactly the same way as the batches deposited by the righthand robot.
Re~erences 1.1 to 1.5 show the origins of the arms 3 of the robots 1 relative to the UUIlVt:yul 11 for receiving and making up layers while the UUIlV~yul is moving.
Dashed lines 19 ~ 1; 7e the positions of the arms while the batches are being deposited. In the example shown, sales items A3, A6, BS, B6, B7, B10, B13, and B16 were deposited individually, while the other items were deposited in batches of two. It should be observed that high speed deposition is made easier by maintaining spaces 21 between batches, which spaces are advantageously reduced or eliminated when the layer 15 is shaped .

, Figure 3 is a flow chart showing a preferred lmpl~ Lc.Llon of the method of the invention for making up layers.
At 23, the ~lUyl -hle controller of the robots 1 or a supervising ~ , _ L~:L loads data concerning the palletization ~ n that is to be performed.
It should be observed that the ~ c,laLus of the present invention makels it possible to generalize the conventional concept of a "palletization ~ n". A
, _-~lgn may correspond to palletizlng a portlon of a .:ux ~ - order, a customer order, a plurality of orders from a single customer, portions of a plurality of orders from a plurality of customers, or a plurality of orders from a plurality of customers. The term "campaign" is used to designate the layers and/or pallets that need to be prepared at a given time. The fl~ hi l i ty of the palletlzing tool of the present lnventlon makes it po~ql hl e- to avoid the constraints of known types of production and palletizing organization, in particular palletizing in the form of uniform pallets each carrying a single-product. However, to avoid disturbing already est~hl i ChP,l production plans and the working methods of people runnlng palletization, it is pr~qq1 hl ~ for various pallets to be built up in conventional manner, i . e. with different types of sales item one after another. In an advantageous variant, the ~al~Lus of the present invention makes it possible to make up progressively the layers re~uired for building up pallets that are uniform or non-uniform, with appropriate batches being applied to and/or taken from the ~UllV'dyUl~ 9.
Go to 25.
At 25, the L,luyl hl.~ controllers of the robots 1 load (or compute) the palletization scheme(s) to be perf ormed .
Go to 27.
At 27, the proyl hlC. controller det~minf~q which tool( s ) to use as a function of the individual sales .

items to be L,Lu.ia,~ d. Advantageously, the appropriate tool is loaded automatically, e.g. from a n~-~A~lno or cylinder suitable for being reached by the end of the arm 3 of each robot 1. In a variant, the approprlate tool is 5 loaded by an operator, e . g . when requested by the robot .
Advantageously, the robot verlfies that the tool that has been loaded ,ulL~o~ullds to the tool requlred for ~el roL..Ilng the ~ SJn loaded at 23 .
Go to 29.
At 29, the ~ n is lnit~l170A, and in particular the ~:UIlV'::yUL~ 9 and 11 are started.
Go to 31.
At 31, the layer to be processed is initialized.
Go to 33.
At 33, the batches 6 to be palletized, i.e. the sales ltems, are detected.
Advantageously, a test ls ~lr ' at 35 and at 37 to verify that the ltem fed by the ~;ollV~yuL 9 corresponds to the item requlred for maklng up the layer.
At 35, the batch 6 ls verified to check it is of the appropriate type, is properly oriented, and in a good state, this being done by a device located above the ~:ollVt:yul 9, or by any other method, e.g. pattern recognition .
If it is not acceptable, go to 37.
If it is acceptable, go to 39.
At 37, the robot does not pick off the unacceptable batch 6 and so the batch is subsequently re~ ected into the receiving r-g~ no 17. The robot walts long enough 30 to receive the following batch 6. Where necessary, the robot sends a t~ ULclLy stop request signal to the uullve:yuL 11 for receiving and making up layers.
Go to 39.
At 39, the arm 3 of the robot 1 takes a batch 6, 35 e. g. a sales item .
Go to 41.

- ~ 2184774 At 41, the ~/lOyL -hl e controller of robot 1 computes the position, for depositing the batch 6 taken at 39 .
Go to 43.
At 43, the robot 1 deposits the batch picked up at 39 on the UUIlV~yul 11.
Go to 45.
At 45, the plùyl, hle controller of the robot 1 det~rml n~q whether the currently being made up layer 15 is complete. This may be done by computing how many batches 6 have been deposited and/or verified by data acquisition using sensors that are not shown.
If not, loop back to 33.
Else go on to 47.
At 47, the proyl hl~ controller of the robot 1 det~rml n~q whether the palletization campaign loaded at 23 has been completed by ~ ,_I,al,~on in which the number of layers made up is compared with the number of layers required .
If completed go on to 49.
Else loop back to 31.
At 31, it should be observed that lt is the next deslred layer which is inif 1~1 i 7e-1, which need not n~mF~qs~rlly be the same as the precedlng layer. The varlous layers ini~l~l;7~1 at 31 correspond to the ~Tnr~ ~ ~n characterlstlcs as loaded at 23 and to the palletization scheme(s) as loaded at 25.
At 49, the programmable controller of the robot 1 sends an end-of-task message enabling the UUllV~:yuLS 9 and 11 to be stopped.
Go to 51.
At 51, the layer make-up, ,-l~n has been completed .
In a variant, at the end of a, ~ ~n, step 47 chains on to a new u ,-~gn by looplng back to 23.
The layers 15 made up on the ~;ullv~yur 1 are conveyed as they are made up to apparatu~3 for building up layers.

218~774 .

Such c~ aLaLus may be constituted, for example, by a~y~lla~us for stacking layers in a known type of palletizing machine. Advantageously, a flexible layer-stacking robot of the present invention i8 used, and an example thereof i9 shown in Figure 4. The layer-stacking robot 53 is, for example, a Cartesian robot having three degrees of freedom along orfhngnn;l1 axes X, Y, and Z.
The robot 53 comprises a structure 55 standing over a zone 57 . 2 for receiving layers, e. g. located at the downstream end of the oUIlV~:yul 11 in Figure 1, and also extending over at least two, and for example, three, four ( as shown ), or more pallet build-up zones 57 .1, 57 . 3, 57.4, and 57.6, where pallets are built up by stacking successive layers. In the example shown in Figure 4, the downstream end of the ~ V~dyUl 11 terminates substantially in the middle of the layer-stacking apparatus 53, and two pallet build-up locations 57.1 and 57.3 are ~1epnsed on either side of the _UllVe:yUl 11.
Advantageously, as represented by arrows 71, two locations 57 .1 and 57 . 3 can be emptied forwards, i . e.
going away from the side where the ~_UllVt:y-~l 11 arrives, while the other two locations 57 . 4 and 57 . 6 can be emptied sideways. In a variant, one of the pallet building-up locations 57, e.g. the location 57.6, can be replaced by a magazine of spacers suitable for putting between two layers by the layer-grasping devices 63 or by means of a special spacer-dispensing device. The structure 55 includes, for example, a rectangular frame 59 carried at its four corners by uprights 61. A layer-grasping device 63 is mounted to move in horizontal translation along the axis X parallel to the long sides of the frame 59 and along the axis Y parallel to the short sides of the frame 59, and also in vertical translation along the axis Z parallel to the uprights 61 through a height that i8 not less than the tallest palletized load that is to be built up. In the example shown in Figure 4, the robot 53 has a bridge 65 running along the long sides of the frame 59 and itself carrying a brldge 67 running therealong parallel to the short sides of the frame 59. A column 69 is mounted onto the bridge 67 and is provided with a ^h.qn~m for raising or lowering the layer-grasping device 63, e. g. a rack ( not shown ) .
D~r~n-l;n~ on the types of load that are palletized, it is possible, for example, to use layer-grasping devices 63 of varlous different types, suction, magnetic, having a fork, or advantageously having curtains as shown in Figures 5 and 6. The device 63 comprises a platform 73, e.g. of sheet metal, coupled to the column 69 of the layer-stacking robot. Advantageously, the platform 73 has a lateral opening 74 for loading one layer of the load to be palletized.
A curtain 75 formed by two half-curtains 75 . l and 75.2 maae up of substantlally toll~hin~ rolls extends over the entlre width of the device 63 parallel to the opening 74 and ls driven by a motor 77 by means of two chains 79 that are connected together so as to form a closed loop.
The rolls of curtaln 75.1 are connected to the top runs of the chains 79, and curtaln rolls 75.2 are connected to the bottom runs of the chains so that when the chains are driven counterclockwise the two half-curtains 75.1 and 75 . 2 are opened whereas when the chains are driven clockwise the half-curtains are moved towards each other, causlng them to close and form the floor of the device 63 containing the layer 15 to be stacked. Advantageously, the device 63 inc:Ludes shapers enabling the spaces 21 to be reduced.
A lateral shaper comprises two parallel side shaping arms 81 and 83 driven by a pneumatic actuator 85 actiny on a linkage comprising a bar 87 mounted to rotate about a point 89 situated halfway between fixing points 91 and 93 of rods 95 and 97 respectively connected to the two shaping arms 81 and 83. As shown in chain-dotted lines, extending the actuator 85 causes the bar 87 to rotate and 21~4774 .

-thus causes the arms 81 to move towards each other in parallel, such that by bearing on the opposlte faces of the layer 15 they cause the spaces 21 to be reduced, or advantageously to rl~ ~rrP~r- In an advantageous variant 5 (not shown), the side shaping arms 81 and 83 are driven by a motor fitted with an encoder Pn::lhl in~ positioning to be pelL, -~1 on command, in particular by program. A
front shaping bar 99 situated remotely from the opening 75 is driven by a motor 101 via a chain 103, the motor 101 having a position encoder. A back shaping bar 105 ad~acent to the opening 74 is driven by a motor 107 via a chain 109, which motor 107 likewise has a position encoder. The back shaping bar 105 is suitable for retracting into a position referenced 105.1 in Fiyure 6 15 so as to enable a layer 15 to be fed in through the opening 74 and is also capable of taking up a position referenced 105 . 2 corrP~pnn l~ n~ to shaping a layer 15 th~t is in position inside the layer-grasping device 63.
The layer-grasping device 63 is brought by the gantry robot 53 into a layer-receiving position 57 . 2 that is in alignment with the end of the conveyor 11.
In a variant, the layer-stacking robot 53 may advantageously be fitted with a device for rotating the layer-grasping device Pn;~hl ;n~ the orientation of the layer to be stacked to be modified on command, e.g.
through 9 0 .
The layer is inserted by being pushed against the double curtain 75 of the layer-grasping device 63 and it bears against the front shaping bar 99, thereby providing a first geometrical reference position. The back shaping bar 105 moves from its reception position 105.1 to its shaping position 105 . 2 and it presses agalnst the layer so as to give it a second reference. The grasping device 63 moves up to its high position and then moves hori20ntally so as to be placed above the receiving - =
pallet. The high position may correspond to the maximum height that the layer-grasping device 63 can reach. In 218~774 .

an lmproved variant, the hlgh posltlon may correspond to the mlnimum helght that will enable the current layer to be deposlted on the preceding layer or on the pallet without risk of cnl l; c1 nn with any part of the robot 53 or of a pallet that ls being built up.
While the layer-grasping device 63 is moving, the lateral shaping arms 81 and 83 compact the layer laterally, thereby pro~viding a third reference. When the layer-grasping devlce 63 has come to a position above the receiving pallet, it moves down and stops a little way above the preceding layer, e.g. 1 cm above it. The half-curtains 75.1 and 75.2 move apart :iy lllcally, thereby depositing the layer whlch contlnues to be guided on all four sides by the shaping bars 81, 83, 99, and 105. The grasping device 63 shown in Figures 5 and 6 is particularly effective since it can adapt automatically to the format of the layers to be stacked, with the half-curtain rolls 75 ~n;~hl i n!J compressed layers of all types of load to be transferred, transfer taking place in complete safety and avoidlng any risk of a load Nevertheless, uslng layer-s~rasplng devices 63 of other types would not go beyond the amblt of the present invention. Similarly, the robot 53 may be provided with a plurality of layer-grasping devices 63 suitable for being used as alternatives. The device 63 which is not in use is advantageously located over one of the locatlons 57, e . g . the location 57 . 4 . The robot 53 selects the layer-grasplng device 63 that is most suited to h;~n(ll ;n~ the particular layers that are to be stacked.
There follows an explanation of one example of a - ~ gn for stacking layers by means of the robot 53 .
The layer-grasping device 63 takes up a position in line with the ~UIIV~:yUL ll (or with a transfer ~;ullVUyuL, not shown), its opening 74 facing towards the ~:UllV~:yUl 11.
The first layer is pushed by the pusher 110 onto the curtain 75 of the layer-grasping device 63 and is then transferred to the pallet located at 57.1. Thls ~18~774 operation ls repeated until the pallet is fully loaded.
The following layers are placed on a pallet located at 57.3.
While the pallet at location 57.3 is being loaded, 5 the palletized load at location 57.1 is removed along arrow 71 in non-critical tlme. Similarly, once the pallet at location 57.3 is fully loaded, the following layers are deposited on a new pallet that has been fed ln the -nwh~le to location 57.1.
It is possible simultaneously to bulld up a non-unlform or an 1 nrl 1 F~te pallet at location 57 . 4 which ls fed alternately with palletization taklng place at locations 57 .1 or 57 . 3 . When the pallet is put into place at 57 . 4, the robot 53 places the number of layers 5 thereon that corresponds to the order in the current n, A palletized load is gaid to be "non-uniform"
when the various layers making it up are not identical.
A palletized load ls said to be "1~ te~ when it lncludes some number of layers that ls smaller than the 20 number of layers ln the other palletlzed loads corr~cr-~n-l i n~ to the same palletizatlon scheme, or when the last layer has a number of sales ltems that is smaller than the other layers. An incomplete palletized load makes it possible to complete a customer order in 25 such a manner as to deliver the desired number of sales items .
It should be observed that feeding the robot 53 of Figure 4 by means of the apparatus of Figure 1 for making up layers makes it possible to send a series of different 30 layers 15 on the conveyor 11. Under such Cil~ Lc-l-ces, each of the locations 57 can be used for building up non-uniform palletized loads. Even under such CiL-.;Ul..e~ La!lces, one of the locations 57, e.g. location 57.4, may receive a partially-built-up palletized load for the purpose of 35 completing lt wlth layers of different kinds so as to form a non-uniform palletized load.

218~77~
.

The robot 53 of the present inventlon may be fitted with means for depositing spacers. For example, the layer-grasping device 63 may include means, in particular retractable suction cups ( not shown ), ~n~hl; ng spacers to 5 be transferred from a spacer r-g:q7inc. situated at 57.6, for example, onto a layer of a palletized load that is belng built up. In a varlant ~ L that can be operated at a faster rate, a ~ :p~ne-~r 111 ( Figure 8 ), e . g . a rotary dispenser, enables a spacer to be placed on 10 the layer arrlving on the ;U-lV~yUL 11.
In a variant embodiment, the robot 53 includes internal means (not shown) for transferrlng empty pallets or for transferrlng palletized loads between the various locations 57.
Naturally the 1 ,1 Lc-Llon of other types of load-stacking robot, e.g. gantry type robots having two axes, Cartesian type robots having three axes on rails, robots having two hinged arms including llnear vertlcal 1~ erl ~ L and known as SCARA robots, or SCARA robots on rails, and also multiply-hinged or spherical robots, would not go beyond the ambit of the present invention.
The layer-stacking robot 53 of Figure 4 is particularly flexible insofar as it has a plurality of locations 57 (57.1, 57.3, 57.4, and 57.6) with at least one of them being for receiving a pallet for the palletized load that is being built up, while the other locations 57 being suitable for performing other functions, e.g. serving as a magazine of layer-grasping devices 63 or as a magazine of spacers.
Advantageously, the robot 53 controls means for detecting the presence of a pallet, for detecting a lack of empty spacers, and/or for detecting unsultable layers, ln partlcular layers that have been damaged or that include damaged portions.
Figure 7 is a flow chart showing how the layer-stacking robot 53 operates.

.

At 113, a supervislng, , uL~l and/or the Jyl hl ~ controller of the robot 53 receives information about the palletizing, , -; ~n to be pelL~ ~1, e.g. from a production n~n~ t computer.
5 This information relates in particular to the load-grasping device 63 to be used, which locations 57 are to be used as deposition points, whether any of the pallets are non-uniform, the fi; ~ nc~ of the layers to be handled, the number of layers per pallet, the number of 10 pallets, the number and the positions of the spacers, the orientations of the layers, etc.... During the '-~''`r~i~n, the above information may optionally be completed by special information, in particular concerning the presence of a non-uniform pallet that is to be completed.
Go to 115.
At 115, the stacks of layers on the pallets corr~pr~n-l~n~ to the various locations 57 used as layer-deposition locations are ini~i ~l i 7c,-i, In the example shown in Figure 4, the number i of locations 57 used for building up layers and corresponding to init;;lli7~n~
pallets 115 .1 to 115 . i lies in the range 2 to 4 .
In a variant, the number i of types of pallet that can be init; ~l i 7e-9 at step 115 is not tied to the number of locations 57 in the robot 53. Advantageously, at 113, the supervising computer and/or the proyl hl f' controller of the robot 53 receives the palletization scheme for all types of palletized load which are to be palletized thereby during the present palletization ~ ,-15n, Thus, during a single, , ;~n, a single location 57 may successively and automatically be implemented to build up various different types of palletized loaa, given the pallet-loading options made available to the user by automatic carts, in particular wire-guided carts.
Go to 117.

, At 117, the layer 15 coming from the UUIlV~yul 11 is detected, or advantageously is identified.
Go to 119.
At 119, the layer is verified to see whether lt is 5 acceptable.
If the layer is not acceptable, go to 121.
If the layer i8 a~ceptable, go to 123.
At 121, an u~acceptable layer is disposed of, e. g. a layer that has been broken, a layer including damaged 10 portions, a layer that is oriented in a direction other than that expected, or a layer that does not correspond to the current palletization scheme.
From 121, go to 117.
At 123, the layer 15 fed by the conveyor 11 is grasped.
Go to 125.
At 125, the grasped layer 15 is shaped.
Go to 127.
At 127, the layer is deposited on a pallet that is being built up.
Go to 129.
At 129, it is detl~rm; n~l whether the deposited layer was the last layer of a pallet.
If not, loop back to 117.
Otherwise, go on to 131.
At 131, a check is performed to see whether the -1 ~n has been completed.
If it has, go on to 133 which causes operation of the robot 53 to stop.
Otherwise, loop back to 135.
At 135, the following pallet is det~rm;n~
Go to 115 to initialize the pallet corresponding to the location 57 where the following pallet is to be built up .
In a variant, the following pallet is de~rm; n~
after layer deposition step 127, thereby f~n~hl ;n~ layers to be deposited alternately on a plurality of pallets.

, Arrow 137 5yP~hnl 1 7P~ recelving instructions to palletize a non-uniform pallet, e.g. a pallet located at 57.4.
Figure 8 shows an ' -~i L of flP--~hle palletizing apparatus IFP of the present invention ~ ' ~n~n~ layer make-up d~aL Cl L.13 analogous to the apparatus shown in Figure 1 ~ut including feed UUIlV~yUL~ 9 for sales items 5 that are located adJacent to the ~;UllVt:yUL 11 on which the layers are made up for feeding layers to be stacked to a layer-stacking robot 53 analogous to that shown in Figure 4. In the example shown, the UUllV~yuL 11 for receiving and making up layers opens out into the middle of a large slde of the robot 53 at a location 57. 5 ' . For the layer-grasping devices that use vertical grasping, the layers 15 are taken from location 57 . 5 ' . However, the device 63 having two lateral loading curtains as shown in Figures 5 and 6, advantageously includes a loading zone 57 . 2 ' situated in line with the end of the ~UllV~yUl 11. In thls embodlment, a pusher llû is dlsposed faclng the locatlon 57 . 2 ' . The pusher 110 beglns by retracting to allow a layer 15 on the UUllV~:yuL 11 to pass to location 57. 5 ' and then moves downwards and pushes the layer in through the opening 75 of the layer-grasping device 63.
The robot 53 may be fed with empty pallets and palletized loads may be removed therefrom manually.
However, it is advantageous to use an automatic device for feedlng empty pallets, e.g. an empty pallet dispenser 137 having an overhead ,UllV ::yUL . Palletlzea loads are advantageously removea on carts or pallet transporters 139 that are autonomouqly guided and automatic. By way of example, such carts can be guided by marklng on the ground or in the ground ( a guide line, a wire-guided cart, etc. ... ), or by eleuLi~ ~nPtic or other signals (laser guided carts, etc.... ).
At 143, there are shown various tools that are suitable for fitting to the arms 3 of the robots 1.

218~774 , In Figure 8, the robots 1 have respective hinged arms 3 with circles 141 symbolizing the reach of the arms 3.
Figure 9 is a flow chart showing one example of how the Figure 8 apparatus can operate when located, for example, at the end of a production line.
At 145, the computer controlling throughput receives the characteristics of a palletizing _ ~n, either as specific inputs, or advantageously directly from applications software for h;qn(~l 1 n~ customer orders.
Go to 147.
At 147, the computer for controlling throughput or for supervising production det~ n~e which palletizing schemes correspond to the sales items ordered by customers and it communicates the schemes for making up layers to the robot 1, and the schemes for stacking layers to the robot 53. Without going beyond the ambit of the present invention, it may also generate production ob~ectives which are sent to a production or pilr.k~n~
line ( not shown ) .
Go to 149.
At 149, the sales items for applying to the UUIlV~yuli 9 are defined.
Go to 151.
At 151, sequential dispatching of sales items on the ( S ) 9 iS initialized.
Go to 153.
At 153, the robots 1 indicate whether the rate at which sales items 5 are arriving on the ~UllV~yUl :i 9 is compatible with making up layers.
If not, go to 155.
Else, go to 157.
At 155, the feed rate of the ~UIlv~yul~i 9 is slowed down .
Go to 158.
At 158, a delay is generated l~n;lhl in~ the robot 1 to return to a rate C-~r.,L,l late for steady conditions .

218477~
, Go to 159 and to 161.
At 157, the rate at which the ~:U'lVe:yUl~ 9 are supplied with sales items 5 i9 increased to a maximum.
In a variant, the ~UIlV~yuLx 9 are fixed speed UUIlVt:yuL ~ and they are 1~R~ ~nG~ to ~ te sales items, thereby providing regulation in the event of the layer make-up robots 1 slowing down.
Go to 159 and 161.
At 159, the robots 1 make up the layers. Step 159 corresponds, for example, to the flow chart of Figure 3.
Go to 161.
At 161, from the moment when the robot 53 receives the first layer 15 from the Cullv~yu. 11, it proceeds to stack layers and build up palletized loads. Step 159 begins before step 161, after which these two steps overlap in time until the last layers have been stacked after step 159 has been stopped. Step 161 corresponds, fcr example, to the flow chart of Figure 7.
Go to 163 and to 167.
At 167, completed palletized loads are removed and transferred .
Go to 169.
At 163, incomplete and non-uniform pallets are removed and transferred either to another palletizing system IFP (at 164) for processing the sales items required for completing the pallet, or else to dynamic storage (at 165) which will store it until a palletizing system IFP is processing the required sales items. Non-uniform pallets can thus be built up during a plurality of campaigns with the pallets being stored temporarily between campaigns.
At 137, while stacking the following desired layers, incomplete pallets are returned from dynamic storage 165 to layer stacking 161.
At 169, palletized loads are advantageously labelled .
Go to 171.

.

At 171, outer wrapping is advantageously installed around palletized loads.
Go to 172.
At 172, the system for managing production or for 5 managing throughput is informed of the location and of the characteristics of each of the various pallets of the campaign in order to enable them to be transferred onto transportation means, e. g. trucks .
Go to 173.
At 173, a check is made to see whether the campalgn has been finished.
If not, loop back to 149.
Else, go on to 175.
At 175, the computer system r~_n;~gln~ production or r-n;~1 n~ throughput is 1 nf, ~1 about any sales items or layers that may have been reJ ected .
Go on to 177.
At 177, any re~ected sales items and/or layers are removed .
Go on to 179.
At 179, the palletization, ~-1!Jn has ended.
Naturally, it would not go beyond the ambit of the present invention to implement apparatuses of the invention that do not include 1 ~hPl l; n!J or wrapping.
Similarly, without going beyond the ambit of the present invention, it is possible for pallet labelling to be performed by the robot 53 using a label printer, e.g.
comprising an alrh lcal message assoclated with a bar code and i , l l ~t:d ln a device for putting on labels.
It should be observed that once layer make-up has been initialized, this operation takes place simultaneously with layer stacking, so that stacking thus takes place in non-critical time. Likewise, once at least one palletized load has been built up, palletized loads are removed (step 167), labelled (step 169), and wrapped ( step 171 ) and then stored in non-critical time.

.

In a variant, partlcularly during short palletizing -1~nc~, wrapping may begin after the palletizlng -1 gn has ended.
Modern production lines, in particular lines for 5 bottling beverages and for grouping together bottled b~:vt:Lclyt:s in sales items operate at ~ 1 y high rates.
Flexible palletizing apparatuses of the present invention can be fed directly at the outlet from a production line to perform palletization in real time, i.e. without any 10 in~F ~ te storage of the sales items produced. To increase throughput, it is possible firstly to lncrease the individual operating rates of the robots 1 and 53.
If that is inappropriate or insufficient, it is possible to use the robots 1 and/or the robots 53 in series or in 15 parallel configurations. It should be observed that the small ground area occupied by a~alcl~uses of the present invention facilitates the construction of large palletizing facilities. In Figure 10, there can be seen a palletizing facility that comprises, four Figure 8 20 flexible palletizing systems IFP disposed in parallel and fed with sales items forming the individual loads from the outlet 181 of a production line. In the example shown, the outlet 181 of the produotion line feeds two wrapping or grouping facilities 183 in parallel. Each 25 facility 183 feeds the two ~,UIIV~yUl~ 9 of two flexible palletizing systems IFP in parallel, e.g. by interconnected conveyors including means for directing sales items to the flexible palletizlng systems IFP that are to be used. Advantageously, the dlstance between two 30 consecutlve flexible palletlzing systems IFP is substantlally equal to the wldth required for leavlng room for a cart or a pallet transporter 139 to pass through, whlch carts or transporters serve the locations 57. 6 and 57. 4 of two consecutlve flexible palleti zing 35 systems in alternation. In thls compact dlsposition, the four flexible palletizing systems IFP occupy a width that is substantially equal to 28 meters, for example. By .

putting the fll~Xihl~ palletlzing systems in parallel or in a battery, it is p.~qRlhl~ to improve throughout ~-n ql L by sending the sales items to one or more IFPs depending on the delivery rate of the productlon line or 5 on the size of the order to be made up. One of the fl-~Yihle palletizing systems may be stopped temporarily for ~l~v~l~L~tive maintenance by switching its work to the other flexible palletizing sys~ems. In addition, it is possible to begin by investing in a small number of 10 flexible palletizing systems and to expand subsequently with additional fl~Xlhl~ palletizing systems as the need arises .
The robots 53 of the flexible palletizing systems are fed with empty pallets, e.g. on forklift trucks or 15 pallet tran:,~Ul L~ , by means of overhead dispensers or from an automatic system of wire-guided carts.
Palletized loads, whether uniform or non-uniform, are removed by forklift trucks, pallet tran~ol Lt:lff, or carts that are guided by wire or by laser beam. The use of 20 autrn~ Ic guided vehicles, whether guided by wire or by laser beam, is particularly advantageous in association with f lexible palletizing systems disposed in parallel, given that such vehicles make it possible for each palletizing campaign to program, without wasting time, 25 optimum paths and duties to be p~lL~ cl by each autonomous guided vehicle, particularly with respect to non-uniform pallets built up at the various locations of the robots 53.
In a first variant embodiment, non-uniform pallets 30 are built up by sending sales items for making up various different types of non-uniform pallet layer to a common flexible palletizing system. However, to avoid disturbing common practice in palletizing, it is possible to organize the feeds to the fle~ible palletizing systems 35 in such a manner as to avoid or to minimize any interleaving of different types of load or layer as processed at each of the flexible palletizing systems.

.

Under such CiL, Lclllces, each different type of load is applied to a different fl~YlhlP palletizing system.
However, that does not prevent non-uniform pallets being made up automatically by ~ lng the method illustrated in Figure ll_ The computer 185 supervising palletization receives an order to build up _ non-uniform pallets which it allocates to available carts 139. An empty pallet is brought to one!of the locations, e.g.
57.4, of a robot 53 of a flPx~hl~ palletizing system that receives the layers 15 which are to build up the lower layer(s) of the non-uniform pallet. After the lower layers have been built up, a cart 139 takes the partially loaded pallet and conveys it to one of the locations 57, e.g. location 57.4 of the robot 53 of the flPx;hle palletizing system for building up the following layers.
The operation can be repeated until a complete pallet has been built up lnrl~l~ln~ all types of desired layer ready for being taken subsequently to a 1 ;:lh~l 1; n!J station and then to a wrapping station 187 prior to being stored in an exit zone 189, or advantageously being loaded directly on transportation means 191, e.g. a truck. For, - i~nq that intend to build up a quantity of non-uniform pallets Pxr~11 n~ the available number of carts 139, a zone 193 is allocated to dynamic storage of pallets that are being built up. On command from the supervisory computer 185, the carts 139 take a non-uniform pallet that is being built up and put it down in a specified and identified location ready to be taken up again when fleYible palletizing systems are being fed with layers of the kind required for completing the pallet. It should be observed that depending on the factory's production plan, a pallet that is being built up may remain for a rr~nqlrlc~rable length of time, e.g. several hours or even several days in the dynamic storage zone 193.
Advantageously, the flexible palletizing systems feed the wrapping stations 187 directly, e.g. by means of the carts 139 and/or ~,~)llV~:y~LH 188. Nevertheless, in a 218477~

variant, all or some of the palletized loads may initially spend some time in the dynamic storage zone 193 prior to being transferred by cart 139 to a wrapping station .
In the example shown in Figure 11, a first cart 139 is transferring a pallet that is being built up between the dynamic storage zone 193 and flexible palletizing system IFP1, a second cart 139 is transferring a pallet that is being built up or a palletized load from flexible palletizing system IFP3 to the dynamic storage zone 193, a third cart 139 is transferring a palletized load between the dynamic storage zone 193 and a wrapping station 187, and a fourth cart 139 is transferring a pallet that is being built up from flexible palletizing system IFP2 to flexible palletizing system IFP3.
Advant~P~-Icly, the, , Ul,~L 185 can be used to simulate a palletizing, ,-~n before it is lAIlnrh~tl so as to show up i n~ n~ qtencies or problems that may be encountered, or on the ~_o~ Ly so as to estimate the time required for performing the palletizing, , ~ ~n So as to make it possible to inform one or more customers about how long it will take to deliver the palletized loads as ordered.
Naturally, without going beyond the ambit of the present invention, it is posslble to build up loads without using pallets, merely by stacking layers.
The present invention ls applicable to hAn~l in!J, storage, and transportation of goods, in particular at the end of a production line.
The main application of the present invention lies in hAn~ll ing, storing, and transporting goods coming from a flexible production line.

Claims (13)

1/ A robot for stacking layers (15) of individual sales items (5) on a pallet, in application of a palletizing scheme, the robot comprising:
a) apparatus (11) for feeding layers (15) to be stacked;
b) means (63) for grasping the layers (15);
c) at least two locations (57) for receiving pallets that are being built up;
d) control means, and in particular a programmable controller; and e) drive and guide means for driving and guiding the means (63) for grasping layers (15), in response to a command received from the control means, to deposit the layer (15) grasped by the layer-grasping means (63) on a preceding layer of a pallet that is being built up, or on the pallet itself if the layer (15) grasped by the means (63) for grasping layers (15) is to become the first layer of a palletized load, which pallet is disposed in any one of said at least two pallet-receiving locations (57).

2/ A robot according to claim 1, characterized in that said robot is a Cartesian gantry robot having three orthogonal axes (X, Y, Z).

3/ A robot according to claim 1 or 2, characterized in that means (63) for grasping layers (15) comprise a platform having its bottom constituted by a curtain (75), and in that the platform includes an opening (74) for being loaded laterally with layers (15).

4/ A robot according to any preceding claim, characterized in that the means (63) for grasping layers (15) include shaper means (81, 83, 99, 105) for ensuring cohesion of the layer (15) that is being deposited on the pallet that is being built up.

5/ A robot according to any preceding claim, characterized in that the device (11) for feeding layers (15) to be stacked comprises a conveyor whose width (L) is substantially equal to and preferably slightly greater than the width (L') of the layers (15) suitable for being grasped by the means (63) for grasping layers (15).

6/ A palletizing system characterized in that it comprises a robot (53) according to any preceding claim, and at least one robot (1) for making up layers on a device (11) for feeding layers (15) to the layer-stacking robot (53).

7/ A system according to claim 6, characterized in that the robot (1) for making up layers (15) includes a moving arm (3) and in that said system includes at least one conveyor (9) for feeding loads (5) to the robot (1) for making up layers (15).

8/ A system according to claim 6 or 7, characterized in that it includes two robots (1) for making up layers, said robots being disposed symmetrically on either side of the device (11) for feeding layers (15) to be stacked to the robot (53) for stacking layers (15).

9/ A system according to claim 6, 7, or 8, characterized in that the robot(s) (1) for making up layers include(s) means for automatically changing batch-grasping tools (143).

10/ A high rate palletizing facility characterized in that it comprises a plurality of palletizing systems (IFP) according to any one of claims 6 to 9 disposed in parallel, together with means for feeding at least two of said palletizing systems (IFP) on command with sales items.

11/ A palletizing method characterized in that it implements a system according to any preceding claim.

12/ A method according to claim 11, for building up non-uniform pallets each comprising a stack of layers of a plurality of types, the method being characterized in that it comprises the steps consisting in:
a) loading into a computer system (185) a scheme for stacking the layers of a non-uniform pallet;
b) depositing the first layer(s) of the pallet by means of a layer-stacking apparatus (53);
c) using an automatic cart (139) under the control of said computer system (185) to remove from the layer-stacking apparatus (53) the pallet which is being built up, in order to wait for layer-stacking apparatus (53) to become available for stacking layers of another type that are to be stacked on the non-uniform pallet;
d) taking the pallet that is being built up to the layer-stacking apparatus (53) having layers that are to be stacked on the non-uniform pallet that is being built up;
e) repeating steps c) and d) until the non-uniform pallet has been completely built up; and f) removing the completed non-uniform pallet from the layer-stacking apparatus (53).

13/ A method according to claim 12, characterized in that during step c), the pallet which is being built up is removed to a dynamic storage zone (193), and in that during step d), the pallet being built up is taken from the dynamic storage zone (193) and brought to the layer-stacking apparatus (53).