FR2628390A1 - APPARATUS AND METHOD FOR REGROUPING ARTICLES BY ENVELOPING - Google Patents

Abstract

A method and apparatus for grouping articles is disclosed. It relates to an apparatus which includes a turntable 108 which can be lifted and an elevator device 16 capable of applying a film around stacks of articles when the turntable is rotated. A brush 90 allows the application of the rear part of the film. The coordinated movements of the turntable 108 and the elevator 16 allow good stabilization of the load. Application to the preparation of loaded pallets.

Description

The present invention relates to apparatus and methods for

  grouping of articles by wrapping after stacking. More specifically, the invention relates to an apparatus for grouping a stack of articles with the aid of a robot, intended to receive articles separated from a feed, to transfer them to an article stacking station. to which the articles are stacked on a "pull sheet" which is a base sheet, in a box with low sides,

  on a pallet or directly on the surface of the job post.

  pounding items, then wrapping a film around the stacked items so that a bundled or palletized load

  stability is built. "In this submission, the former

  "Palletizing apparatus" pressure and derivatives such as "palletizing, palletizing, pallet" and the like are used to designate any type of bundle of stacked articles, the articles being stacked on a pallet, on a surface formed by a sheet or on the surface of

  turntable of the aggregating apparatus when

  a bottom sheet or pallet is used.

  In known palletizing systems, a product is normally advanced to a pallet

  on a support base. Each article or group of articles

  The palletized load elements are then placed on the pallet at a location such that the number of elements that can be stacked on a pallet is maximum, with also nesting test of the elements so that they give

  some stability to the load when it was fully

accumulated on the pallet.

  After stacking articles or elements to form a complete pallet, it is then removed from the base and transmitted to a packaging station comprising a tape application machine, a shrink wrapping machine , stretch wrapping apparatus or other type of wrapping apparatus. At this packing station, the palletized load is wrapped or surrounded by a band so that continuity and stability of the load are ensured. The apparatus or device described herein constitutes an advanced robotic battery stacking apparatus or palletizer which itself constitutes an improved palletizing assembly which includes a programmable material handling element which, for example, removes one or more items from stack on a

  feed conveyor or a feed location

  tation and then positions these items on a pallet or already palletized items. The programmed material handling element stacks the items to

  a previously assigned location on the pallet,

  a certain degree of stabilization of the charge by

  interlocking or overlapping or stacking

  placed on the pallet. This nesting is not a true nesting of stacked articles but rather an overlap of boxes stacked on top of each other so that straight columns are not

  formed by boxes or stacked items. In many

  In many cases, palletized loads do not have significant stability.

  An apparatus allowing the pallet apparatus

  robotization of winding a film of plastic material which facilitates the stabilization of the palletized load around the stacked pallet, is integral with the apparatus

  advanced palletizing robot.

  The robotic palletizing apparatus comprises

  sensors or, alternatively, executes a pre-programmed sequence

  programmed scheduling of operations controlling the palletizing apparatus to begin packing the load at the most favorable intermediate layers, before the stack reaches the final height and the

charge is fully packed.

  A film feed source is supported by

  palletising equipment and can move vertically

  calmly when the film is unrolled, being guided by various rollers so that the accumulated articles on the pallet are wrapped when the pallet is "built". One of the advantages of the invention is that the stacks or columns of boxes or articles can be made because the palletized load is wrapped at certain intervals during the construction of the palletized load so that the integrity of the stack is increased. The possibility of forming piles in columns and not nested batteries as in known palletizing devices, allows the use of the own mechanical strength of the boxes or cartons for the formation of sturdy batteries grouped together

  and solidarized formed by the products. This allows

  the use of a greater height of batteries, the formation of heavier loads, the denser loading of a pallet so that the use of pallets is better, and corresponding advantages can be obtained, such as reduction of shipping costs and especially the reduction of the deterioration of the contents of the

  cartons due to the collapse of boxes of lower levels

laughter of the pile.

  Other features and advantages of the invention

  will be better understood by reading the description

  which follows, with reference to the accompanying drawings in which: Figure 1 is a simplified perspective of an apparatus according to the invention; Figure 2 is a plan view of the apparatus of Figure 1;

  FIG. 3 is a diagrammatic plan view

  sensing the path of passage of a film in the apparatus;

  FIG. 4 is a schematic plan view of the

same in Figure 1;

  FIG. 5 is a schematic plan view of the app.

  same in Figure 1; Figure 6 is a graph showing different

  synchronization elements during a turn of the turntable

  ing; Figure 7 is a perspective of a variant of a part of an apparatus according to the invention; and Figure 8 is a perspective of a device according to

  another embodiment of the invention.

  The representation of FIG. 1 indicates the general arrangement of the palletizer and this figure is first described. Identical references of others

  figures designate the same elements.

  The palletizing apparatus 10 comprises three

  major components. These are the turntable which bears the general reference 12 and which can rotate at any desired speed, the robot palletizing apparatus 14 and the film elevator 16. Several secondary constituents

  of a preferred embodiment of palletizing apparatus

  are also represented. A food transporter 18

  Pallet entry or pallet entry is arranged near the turntable and transmits a pallet to the turntable on demand. When a pallet is fully loaded and

  packaged, it is moved to the evacuation transporter 20

  pallet cuation. The product received is directed towards the

  same palletizing by the carrier 22 of products.

  As previously discussed herein, the apparatus is intended to stack and package articles on different surfaces such as "pull sheets", base sheets, low side boxes and the like or even directly to the surface of

  turntable. A preferred embodiment may

  stack on a conventional pallet, although

  usefulness can be obtained when using

  the device for stacking and packaging with other possibilities, for example on the surface of the turntable.

  In the case where a conventional pallet is not used

  it may be advantageous to eliminate, if necessary, the pallet carrier and possibly the transporter

Release.

  Logically, from the carrier 22 of

  a feed conveyor 24 in quantity

  is the first element which, in the course of

  of the palletizer, is met

  by an article or packaging such as 25 which must be palet-

  ised. The box, package or article as may be any configuration allowing stacking for shipping or storage on a pallet, pull sheet or the like on the surface of the turntable. For example, the device 25 may be a cardboard box, a metal box, a cardboard box, a cardboard box whose upper part is open, a plate carrying a material, nested elements such as buckets, or even bags or flexible packaging of material, containers or pouches. The expression "device in a box" is not

  not intended to limit the invention and is used

  a generic term for stackable materials stacked on top of one another. Thus, in this specification, the term "boxed device" refers to

"boxes" or derivatives.

  The input conveyor 24 which measures the flow rate may have a rough-surfaced upper belt intended to ensure separation between the boxes when they are transmitted to the conveyor 22. The boxes may be aligned on one side of the input conveyor by an adjustable guide rail (not shown). The product carrier, also constituting a substation conveyor or an entry station, is a driven roller assembly, in a preferred embodiment. At least two sets of photoelectric sensors are used on this carrier. Each set 26a, 26b and 28a, 28b includes a first source element and receiver, carrying the

  suffix a, and a reflector, bearing a suffix b,

  seeing the light from the source to the receiver. This is a classic technology. Various types of sensors that may or may not require reflectors may be used in place of the previously mentioned photoelectric sensor assemblies. In this specification reference is made to photoelectric sensors and reflectors, but it is merely an example of a detector device that can be implemented within the scope of the invention. The first photoelectric sensor assembly 26 is used for counting the boxes reaching the post carrier. The second photoelectric sensor assembly is used to detect when the last of a set of boxes 34 has been placed on the carrier of the

workplace.

  A "set of boxes" 34 is constituted by the

  amount of boxes that must be accumulated before

  removal by the robotic palletizing device

  on a turntable bearing the general reference 12. A set of boxes 34 may comprise, for example, four boxes placed in mutual contact on the conveyor.

workstation.

  A cardboard stop that stops the boxes on the carrier is marked by the reference 30. Other board stops not shown can be placed under the support of the rollers and controlled if necessary so that spaces are formed between the boxes that

are accumulated.

  When a set of boxes 34 has been accumulated, the robotic palletizing apparatus can transfer them onto a pallet which is waiting for them on the turntable 12. The boxes which arrive upstream and which are not necessary for the formation of a set of boxes are stopped until the complete set of boxes has been taken by the robotic palletizing apparatus and has cleared the

carrier of the workstation.

  In a normal cycle, a pallet 32 or the equivalent of a pallet such as a sled, a "pull sheet", a platform forming a base sheet, a

  container or the like, is in position on the turntable

  ing. Obviously, in the case where the bundled load is to be constructed without a pallet or base sheet, no pallet or the like has to be in position. The set of boxes 34 is then lifted by the gripping device 36 which may comprise a "hand" chosen from many existing types. Figure 1 illustrates the use of "palms" 38 two of which are located, one placed inward and the other outward. One of the palms is fixed and the other is movable and can be controlled by a pneumatic cylinder (or other operating or closing device) so that the palms move closer to the set of boxes 34 and tighten and grip the cans

  between the palms. The type of "hand" is determined by the

  application and industry is known a very large number of types of hands, including support hands by the lower part to several palms, ensuring for example a vacuum clamping or clamping from above and

  from below, etc. The hand can also be articulated or

  bile on its support around an axis perpendicular to

the axis of the arrow.

  The structure of the gripping device 36 is carried by cam rollers on an arrow 40. The rollers of the gripper device move, in the case of the upper rail, on rails 42 and 44 so that the gripping device 36 can move laterally from a location above the conveyor 22 to a particular location on the pallet

found on the turntable 12.

  The boom 40 is mounted on the mast 46 so that it can slide so that the boom can move vertically on the mast. In an example of a sampling and positioning device, the two axes obtained using the mat and the arrow are sufficient for the transfer of boxes or sets of boxes from a conveyor 22 to the pallet 32. The operation is the following. The hand 36, placed above the set of boxes 34, is lowered, the clamping members of the hand cause the tightening of all the boxes by the palms, the arrow rises on the mast, the device 36 of capture moves along the arrow 40, the arrow 40 down along the mast 46, the hand opens and deposits the set of boxes 34 on the pallet to a

  predetermined location. When returning to the initial position

  tial, the palms of the gripping device 36 are open and spaced from each other, the arrow goes up above the pallet, the gripping devices 36 return along the arrow 40, the latter descends the along the mast 46 and the gripper is ready to grab another set of boxes. The palletizer is programmed in such a way that it starts the movement, that it ensures this displacement, that it modifies the speed and that it finds the position suitable for the palletization of the sets of

  boxes according to the predetermined predetermined stacking pattern.

  When a palletized load has been partially constructed and is stacked with a predetermined pattern, the partially palletized load may be partially wrapped with a film so that load stability

  partially palletized is increased. Stack drawing

  has traditionally been made in a form that attempts to maximize the number of boxes carried by the high pallet, with interlocking boxes so that the stability and integrity of the pallet load are

  increased. Often, some boxes need to be

  next to one axis of the pallet and that other boxes are aligned along a second axis. In the layer or the following level of boxes, the latter are aligned in

  opposite directions so that a certain nesting is obtained.

  It is rare that the boxes are stacked in vertical columns by the current palletizing devices. Although the strength of the columns is much higher when the boxes are stacked directly on each other and they can be arranged so that the most robust parts of the boxes, that is to say the corners, are stacked on each other from one box to another, the resulting column of great height is very

  unstable and totally unusable in practice. How-

  However, the invention allows efficient stacking in columns

  so that the apparatus according to the invention makes it possible

  palletized loads more stable and robust than

  those that have been formed so far.

  When a partial load has been stacked on a pallet or pallet device, the partial load which can have only two layers of boxes (the package can be made when a single layer of boxes has been stacked on the pallet but this does not constitute a preferred embodiment), the packaging operation begins under the control of the control device of the apparatus of

palletizing.

  The wrapping device, usually a plastic film having high hysteresis properties after initial stretching, known as a shrink wrapping film, constitutes the device.

  preferred packaging for the implementation of the apparatus

  lage. This wrapping device can be constituted

  by other types of film, for example a thermoformed film

  retractable, a polymer film, a perforated film, a net, a paper coated or not, a ribbon, protective organs

  such as bubble wrap, and other

  very covering materials or the like. For convenience, the wrapping device is called "film"

in this memo.

  The film represented in the form of a roll 48 of film is carried by an elevating member carrying the reference

  16 (film distribution set or distribution set)

  of the wrapping device) which is mounted

  so that it can slide on a vertical track 50.

  A chain hoist is used for the lifting of the

  vateur. The chain 52 is attached to the elevator at both ends and passes around a motor (not shown) placed within the vertical support 54 for convenience. The film is threaded (see Figure 3) from the roller 48 and passes around a first roller

  main 56 then around a second primary driving roller

  58. These two rollers introduce an important tension

  aunt in the movie (called "pre-stretching"). The film then passes over an oscillating roller 60 which is mounted so that it is movable and adjusts the driving speed of the rollers 56 and 58, so that the speed of the main driving rollers can increase as the consumption of the film increases. and decrease when it decreases. The film 62, when it has left the pre-stretching head with the general reference 16, passes over the guide roller 64,

  on a first roller 66 with a guide arm and a

  cond roll 68 with guide arms which are both mounted on a guide arm 70. The film is then directed to

  the film clamping device or the wrapping device

  72 which is mounted on the turntable bearing the

general reference 12.

  The film guide arm 70 directs the film around the mast 46 and towards the film clamping member 72 mounted on the plate 12. In a preferred embodiment, the film guide arm is held in a fixed position but can being articulated so that it pivots about its point of attachment to the film elevator designated by general reference 16. If the guide arm is mounted in articulated form, a resistance exerted by a spring, a pneumatic cylinder or the like, opposing the pivoting, can be advantageous for the conservation of the tension of the film

to the clamping device 72.

  In a variant, an articulated guide arm, controlled by a motor of any type, under the action of gravity or by springs, can be programmed

  so that it is recalled from a first position to a second

  conde position with maintenance of tension in the film especially when it must be stretched and released. The provision of a pivoting guide arm allows adjustment and minimization of the elongation and then the

  relaxation of the film. We return to the description of the mode of

  preferred embodiment; the height of the guide arm and the length of the rollers of the guide arm are such that the length or height is sufficient for the passage of the film on

* 11

  its entire width when unrolled. For example, the

  The film may be approximately 50 cm wide, but

  Wider or narrower enveloping positives are commonly used. It is also not uncommon for the film used to have a width equal to or greater than 1 m or less

less than or equal to 25 cm.

  The plan views of Figures 2, 3 and 4 make it easier to

  understanding of the operation of the device.

  For example, in Figure 2, the turntable 12 is shown with at least one partial load of boxes already in position. The mast 46, the arrow 40, the gripping device 36, the product conveyor 22, the rollers have been removed from the figures for reasons of simplicity, the film elevator 16 is shown schematically. In

  in addition, the pallet feed conveyor 18 and the conveyor

  Pallet evacuation carrier 20 is shown with an empty pallet 32 and a fully palletized load 33 on the respective inlet and outlet conveyors.

  respectively. The important features that

  easily appear and can be more easily understood in FIG. 2 than in FIG.

  "lines of sight" of the third photo sensor assembly

  74a, 74b, and sensor assembly 98a, 98b

  photoelectric detection-pallet. In addition, the posi-

  Brush 92 is shown in full lines for fixing the load, and dotted in its other position, the brush being pivotable away from

charging or approaching it.

  As noted elsewhere in this memo,

  the assembly 98 is a conventional assembly having a transmitter

  a beam receiver such as 98a and a reflector such as 98b which returns the beam to the receiver, unless a pallet (or other element) stops the beam

  luminous. When the beam is stopped, the

  The palletizing machine knows that a pallet is in position and it can control the stacking of boxes on the pallet. When a base or pull sheet is the surface on which the boxes are stacked, the photoelectric sensor assembly 98 may be

  replaced by a photoelectric sensor detection system

  reflective pole or a manual or automatic switch

  tick or the like may transmit a signal to the controller so that it can start stacking the boxes. It should also be noted that the boxes can be stacked directly on the surface of the turntable so that they can be transported by a device cart.

tightening, if necessary.

  The third set 74a, 74b with photoelectric sensor

  also appears on this figure. This set of

  Tect the upper part of a layer of boxes. The

  The formed signal is used by the controller for setting the vertical limit upwards.

of the elevator 16.

  FIGS. 2 and 3 also represent the path of the film going from the elevator 16 to the seizing member 72 of the

  movie. In FIG. 3, the roll of film 48 from

  which film 62 is unwound is shown schematically

  in plan. Film 62 goes around a first and a second

  cond main drive roller 56 and .58 which are.

  with a difference in speed, in a preferred embodiment, which provides a pre-stretching of the

  film, before passing over a swinging roller 60 and a roller

  The guidewire 64. The film then passes on first and second guide arm rolls 66 and 68 and then reaches the film clamp 72 which is shown in FIG.

  its "rest" position (in the present embodiment)

  fere) in all figures except Figures 4 and 5.

  Figures 4 and 5 show intermediate steps

  example of a stacking and packaging cycle.

  In Figure 4, a packaging cycle has begun and the turntable has rotated 90 in a clockwise direction

  of a watch, for example, in a first cycle of winding

  LEMENT. The film 62 is held tight in the device 72 and it is noted that it is in contact with the corner of the stack of boxes carried by the turntable. When the turntable reaches the rest position, a winding has been formed around the stack of boxes. The cycle continues

  as described herein.

  Figure 5 shows the loading or position

  of an empty pallet. Like the device 72 of

  film ridge is normally vertically disposed at the end of full winding of a load and is in the "rest" position shown in Figure 2, the film clamp (with film 62) must be is

  spaced from the path of the pallet 32 when loaded.

  A possibility for this purpose includes rotating the turntable counterclockwise 900 as shown in this figure. It should be noted that the film 62 is stretched when the film clamp is in the position shown in the figure. The beam of the pallet detection photoelectric sensor 98a was cut when the pallet 32 moved further

  in position on the turntable.

  A packing cycle of a palletizer according to a preferred embodiment shown in Fig. 1 begins under the control of the palletizer controller when a signal is received by this apparatus and indicates that the desired box height for the first wrapping cycle has been reached. Good performance of the machine and good integrity of

  the stack are obtained when the first cycle of envelop-

  This is done after two layers of boxes have been positioned. In the first wrapping cycle, the film is

  maintained tight in the clamping device 72. The provision

  The seizure 36 has moved away from the pallet having the partial stack, during its cycle, and continues to describe its

  cycle so that it takes the next set of boxes

  as the first wrapping cycle is performed. Turntable 12 rotates clockwise from a home position (in top view), this position corresponding to position 0 and 360 in this preferred embodiment, so that the film is drawn from the roll of film 48. At a time close to the beginning of rotation rotating rotation, that is to say a little before, a little after or at the same time, the elevator 16- received a

  signal from the controller of the palletizer

  to move vertically in the vertical direction

  50. This upward movement of the elevator causes the lower switch 78 to open. The upward movement of the elevator causes the spiral film to move along the stack of boxes placed on the pallet when the turntable continues to turn. The film is then wrapped around the stack while being held by

the clamping device 72.

  The first wrapping cycle continues until the palletizer detects the arrival at the top of the top layer of boxes. In

  In general, the first wrapping cycle is carried out

  360 rotation of the turntable but more

  one turn may be advantageous in some applications.

  tions. The signal indicating that the upper layer of boxes has been reached comes from the photoelectric sensor 74a which transmits a light beam to a reflector 74b mounted on a vertical support or a reflector post. The

  reflector 74b is a continuous reflector of no.

  table mounted on the reflector pole, the length of which

  made it correspond to boxes of different heights. When the photoelectric sensor 72a detects the upper part of boxes, it indicates it to the body of

  control of the palletizing apparatus so that the arrangement

  the film elevator drive can stop

  to raise the elevator. At this moment, the turntable

  continued to rotate until it returned to

  rest. The device 72 for clamping the film

holds the film in a tight position.

  Although the film elevator is normally set so that it stops going back to a place where the film does not exceed the top of the boxes placed on the

  pallet, it may be advantageous in some cases

  put the elevator up higher. For example, if the elevator reaches a point where the film is 5 cm above the top surface of the boxes, the film is stretched and can be pulled inward on the outer edges of the boxes. This may be advantageous for stack stabilization if the next set of boxes

  is then placed on this part of film turned towards the

TER AL.

  When the turntable is back in position

  of rest, a stacking set starts to pile up from

  very layers of boxes on the pallet. It stacks up for example

  fold two more layers of products and indicate the beginning of the wrapping cycle. The second cycle of wrapping and

  the following are a repetition of the first cycle of

  development, in a preferred embodiment, up to

  the entire height of the palletised load is at-

  color, the total height corresponding to the number of

  boxes that have been previously programmed into the

  control unit of the palletizer.

  When a fully stacked charge has been accumulated on the turntable, the upper portion of the upper layer boxes is detected by the third photoelectric sensor assembly 74 and the elevator ceases to raise the film roll so that it can not go over the top of the stack. This is a similar operation to the detection of cycles

spiral wound winding.

  As previously stated for the description of

  the interruption of the first wrapping cycle, the film can rise higher than the upper part of the upper layer of boxes so that the complete load of stacked articles can undergo-a better grouping. The film elevator can be programmed so that it passes slightly

  higher than the upper part of the boxes, either

  diatement either after several wraps have been

  formed at the top of the pile.

  When the spiral wrap film was applied

* That on all the palletized load, a bundling wrap of the palletized load is desirable so that this load undergoes a better regrouping, either

  strengthened and integrated. Although the envelopment

  achieved during the first wrapping cycle and the subsequent cycles provides the grouping and facilitates the support of the load during stacking, including the construction of a load formed of boxes stacked in columns, among other advantages, work

  of packaging may or may not be sufficient for the integration

  the palletised load is ensured.

  It may be desirable, in one variant, to complete the entire wrapping of the pallet load when the stack has been formed. In this case, at. the place of the progressive spiral wrapping, the control member maintains the horizontal position of the wrapping head when the turntable performs one or more turns so that the stack is wrapped at this level. This can be done at various heights of the stack when it is under construction. This reduces the winding time after the load has been stacked because part of the winding can be performed during "picking" by the stacker. An additional wrap, in a mode of

  preferred embodiment of the invention may be realized

  in the following way. When the film elevator is in the up position on the vertical track 50 and when the photoelectric sensor 72 indicates that it does not

  should not rise higher, the control device of the

  The palletizing machine indicates to the turntable

  at least one complete revolution, three laps

  faction, while the elevator is held in position relative to the upper part of the load. When the

  number of laps has ensured the application of a

  the elevator is controlled so that it can descend along the vertical track 50 with a set speed while the palletized load continues to rotate.The elevator can be controlled to maintain its horizontal or vertical position. it goes down at a low speed so that a larger amount of film is applied to designated heights of the load or it can continue to descend so that a spiral wrap of the

  load is realized during its displacement.

  An intermediate sensor or switch 76, for example a microswitch or the like, indicates to the controller of the palletizing apparatus when the lower part of the elevator is just above the upper part of the clamping member 72 which, at this

  moment of the cycle, still squeezes the anterior edge of the film.

  When this intermediate switch 76 is closed, the control member of the palletizing apparatus indicates to the clamp member to move back and release the front edge of the film. When the clamping member has moved back to a position which is for example below the

  lower part of the first layer of boxes, the elevation

  16 can continue its descent and wrap the lower part of the palletized load with several layers

  of film, during several turns of the turntable.

  In a variant of the first spiral wrapping cycle or the first or the second rotation of a complete wrapping cycle of the upper part, the film wrapping apparatus can position a

  part of the film, of the order of a few centimeters,

  the film above the upper part of the upper edge of the upper layer of the box. This gives better integrity for some types of stacked products. It is possible to use this technique for the intermediate levels of the spiral wrapping operation, but this technique is not the mode of

most advantageous realization.

  In some cases, it is desirable that the film be placed over the support pallet, the box

  lower or similar on which the articles are

  Battery. This ensures continuity between the pallet of

  port and articles so that these and the pallet are packaged together to a certain extent. This

  is not always necessary or desirable.

  We consider again the end of the cycle; the front edge of the film was quickly covered, at least partially, by the film wrapping the palletized load when the elevator reaches the lower section of the load. Although the anterior edge of the film is rapidly covered by rapid rotation of the turntable, it has been found that a stream of air directed towards the free anterior edge of the film is advantageous so that this anterior edge is held against the load up to that the film can be covered with subsequent layers. An air jet nozzle 76 which receives air from a supply (not shown) of the turntable, is mounted on this

last so that she plays this role.

  During the final turn of the turntable after the desired number of turns or wraps has been achieved, the

  The film must be placed in the clamping device before

  following palletization ration. This operation is

  in the final part of 1800 of the rotation of the

  rotating water. The film clamping members are in position

  recessed at the beginning of the tightening cycle. After the turntable has rotated 180 during its final rotation, a signal is transmitted to the palletizing controller to extend the rear portion 84 of the film clamp. It should be noted that the device 72 for clamping the film is formed of two main clamping elements. These elements include an element

  82 and a posterior element 84. The previous element

  The invention is a robust member having a surface facilitating attachment, for example a rubber coating on the surface which is in contact with the film. The posterior element 84 is also a robust member having a surface ensuring a

  good hanging. When the film is placed between the

  anterior and posterior, it is firmly held until the clamping member is open (just before the elevator 16 reaches the vicinity of the member 72).

clamping film).

  When the posterior element 84 has been deployed in

  vertical position, the previous element is still in

  receding or horizontal in general, and further rotation of the turntable causes the rear member 84 to come into contact with the film between the palletized load and the film guide arm 70. The turntable continues to rotate and during this further rotation, the front member of the film clamp is deployed in position so that the film is clamped between the prior and

  posterior of the clamping device.

  The film is then clamped into the

  rabies but is still fixed in the form of a continuous leaf

  bare, with fully wrapped palletized load. It has been found that, for cutting the film, a heated rod hinged to intersect the path of the film ensures a clean cut of the film. Such a device for cutting or terminating a heated rod film is represented at 86 in

  recessed position on the turntable. The heating rod

  fairy is carried by a support that is mounted in form

  articulated at one end and that can be maneuvered

  controlled by a pneumatic cylinder (not shown).

  When the film has been cut by the heated rod or other film-terminating device such as hot wire, knife or the like, the palletized load is

  completed and it can be moved away from the turntable.

  In a preferred embodiment, the turntable has a driven roll platform surface 88 which allows the palletized load to be evacuated to a pallet evacuation conveyor bearing the reference

general 20.

  However, it was found that before extraction of the

  palletised load of the turntable, it was desirable

  table, in some applications, that the posterior end

  the film is "smoothed" so that the trapped air is driven out and allows a better adhesion of the posterior part to the load. This posterior end of the film is normally bonded to the film placed on the palletized load because it has a tendency to "elastically recover" to a certain extent after being cut by the heating knife 86. Nevertheless, a possible step of the palletising process according to the invention. invention includes the "smoothing" of

  the end of the film, for example using a

  90 positive fixation. The latter, which is shown in FIG. 1, is in the form of a brush 92 carried by a post 94 and having a device 96 for driving the brush 92 when the pallet leaves the turntable towards the conveyor 20. evacuation. The brush may be elastically biased against the palletized load near the posterior end of the film so that it smooths the posterior end of the film placed on the pallet. The fixing device can be of a

  one of several known types, for example a roller with

  smooth or hard surface side, an air jet directed towards the posterior end of the film, a fixed ramp which exerts pressure on the posterior portion of the film when it is transmitted to the pallet evacuation conveyor, or the like. In the situations as indicated in FIG. 5, when the film 62 "relaxes" during the rotation of the turntable counterclockwise and is stretched again when the device 72

  tightening takes the position represented at 90, we have

  state that it was advantageous to adjust the preliminary stretching

  introduced into the film by the pre-stretching rollers

  lable, that is the first and the second main roll.

  drive pad 56 and 58, so that the film is not

not unwound excessively.

  Fig. 6 is a graph showing how the rollers 56 and 58 are operated and stopped so that the film does not feed in excessive amounts. It should be noted that the driving rollers 56 and 58 are operated such that they remove the film from the roll 48 under the control of the oscillating roller 60 which can move inward as indicated by the arrow in the figure. -3 when more film is needed. This is the current film unwinding process. However, when using a pre-stretch film, the film, after having undergone prior stretching

  between rollers 56 and 58, is "re-established" and

  it causes a movement of the oscillating roller 60 inwards and the initiation of the advance ensured by the rollers 56 and 58. This occurs of a set degree each time the film is not wound on the boxes, for example when

  the turntable is in the rest position.

  The graph in Figure 6 shows how the whole

  preliminary stretching process ceases to function or is

  during the final rotation of the cycle of

  developing and inverting the turntable so that the pallet can be loaded. The controller receives limit switch signals which are arranged

  way they detect the position of the turntable.

  From point A to point B (the arrows indicate the direction of movement of the turntable),

  the preliminary stretching assembly of the film is in operation

  That is, provides the film advance during this final rotation of the load and the turntable. At point B, which corresponds to a rotation of about 330, the preliminary stretching assembly stops working and eliminates the possibility of advance of the film (B1 to C). From C1 to D, the turntable rotates in the clockwise direction up to about 270 as indicated

  in FIG. 5, and the pre-stretching assembly does not function

  not work. When the pallet is loaded, the turntable rotates in a clockwise direction and at an angle of about 3300 (D to E) the pre-stretching assembly is stopped. The pre-stretching assembly is returned to operation for the duration of the end of the turn (E to F). FIG. 7 shows a variant of the invention concerning the use of a short film clamping member 100. The other aspects of this embodiment are the same as in FIG. 1, except for the short film clamping member 100, additional film tightening roller 102 and the different position of lower switch 78 which is placed on its support at a position lower than that of the mode switch.

embodiment of Figure 1.

  In this embodiment, the clamping member 100

  of film has a length less than the width of the film 62.

  The latter is thus tightened as shown so that it

  passes through the jaws of the film clamp.

  The 16 film elevator descended so low on the way

  vertical 50, because of the low position of the

  78, that the film can rub against the upper face of the turntable. The tightening roller 102 guides the film over the surface of the turntable and therefore has

  tendency to tighten the film down.

  The advantage of this short clamping member 100 is that, during the initial windings on the lower layers of boxes, the elevator does not have to be raised so much as not to come into contact with the short film clamping member. only in the case of using a larger clamping member (Figure 1). This allows a greater winding at the bottom of the stacked boxes, and

  this may be advantageous in the case of certain loads.

  Figure 8 shows another embodiment of the invention. It represents a classic palletizer of

  crates, of the type sold in a general way by the

  dant. The conventional palletizer has been shaped into a palletizer according to the invention by means of modifications which allow the wrapping of a layer of articles of the

  previously described, in the set of palettisa-

  itself. The grouping or palettisa-

  106, has been modified by mounting a turntable 108 which can be raised in place of a platform which can be raised, by

  mounting a film raising device carrying the refe-

  16 and as previously described, on one of the support bases 110, and by mounting a fixing device or application or brush 90 on a second

  support pedestal 112 of the palletizer.

  In this embodiment, a stack of articles is placed on the turntable when it is at the top of its stroke. The first layer of boxes is placed on the turntable and is driven

  in rotation so that it is enveloped, the cycle of enve-

  the development being as previously described in the preferred embodiment, and the turntable is then

  lowered so that he receives the next layer of boxes.

  The film elevator can descend with the turntable and can move up its guide surface during wrapping or it can remain in the raised position and provide wrapping after the turntable has been lowered. The film elevator can be raised and lowered along the guide surface 114 and can be lifted and lowered independently of the rotating platen. This allows the wrapping of an entire load stacked on the pallet, from the top or the bottom of the stack, when the

  turntable is lowered to a low level.

  In this embodiment, the film guide arm 70 and the associated members can be eliminated because

  the output of the film is close enough to the battery

  developed so that they are not necessary. In addition, this palletizer has no arrow such as 40 which moves vertically along a mast and which can possibly

to obstruct the passage of film 62.

  Of course, various modifications can be made by those skilled in the art stacking apparatus and grouping of a set of articles in the form of a bundled package, and processes that have just been described only to non-limiting examples without departing from the scope of the invention.

Claims (8)

  1. Apparatus for forming a stack of grouped articles, characterized in that it comprises: a turntable (108> which can be raised and is intended to support the stack of articles, a palletizing apparatus (14) for stacking items on the turntable, a device (16) for presenting a wrapping device to the turntable and a cutter device (86) for   cut the wrapping device.   2. Apparatus according to claim 1, characterized in that it further comprises:   a control member for causing rotation   the turntable (108) which can be raised, the control member triggering the stacking of the articles on the turntable, the control member triggering the presentation of the   wrapping device by the display device tion (16), and   the control device triggering the cutting of the disc   positive wrapping by the cutter device (86). 3. Apparatus according to claim 2, characterized in that the control member performs one of its functions   triggering at the same time as another of its func- triggers.   4. Apparatus according to claim 3, characterized in that the device (16) for presenting the wrapping device comprises a unwinding device, a first and a second main drive roller (56, 58) for unwinding the device wrapping device of the presentation device, and a film guiding arm (70) for facilitating the presentation of the device   wrapping on the turntable.   Apparatus according to claim 4, characterized in that   the turntable (108) which can be lifted up 26-28390   carries a cutter device (86).   6. Apparatus according to claim 5, characterized in that it further comprises a device (90) for controlling   the posterior edge, placed near the turntable.   7. A method of grouping a stack of articles, characterized in that it comprises the following steps: the advance of an empty pallet (32) on a turntable (108) which can be raised, the accumulation a number of articles to be stacked above a turnable platen (108), the transfer of articles onto the pallet (32),   the repetition of the stages of accumulation and trans-   during a number of accumulations and trans-   ferts, the rotation drive of the pallet (32) when the turnable turntable (108) rotates, the advance of the film unwound from a roll to the tray   turning wheel (108) which can be raised when   it turns and is lifted, and cutting the film after at least one turn of the board turning that can be lifted.   8. A method of stacking and wrapping a   Apparently articles on a pallet (32) with a wrapping device from a set of   wrapping device so that the stability and the inte-   of the set of articles carried by the pallet are increased, characterized in that it comprises the following steps: the arrangement of the pallet (32) on a turntable (108) which can be raised, the stack of articles on pallet (32), rotational drive of turntable (108)   that can be lifted so that the wrapping device   be unloaded from the reeling unit, 262,839.   positioning the film around the set of ar-   tics, and the interruption of the transmission of the device   wrapping the whole reeling.