|
(11) | EP 0 610 100 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||||||
| (54) | Storage and stacking tray for articles |
| (57) A thermo-formed tray (3) carries staggered rows of bottles (1) as one of five such
trays stacked one upon the other. The tray (3) is stacked on the tops of bottles (1)
of the tray immediately below, with the tops engaged in channels (9) of the tray's
under-surface (7). The closed-end channels (9) are defined by troughs (6) and (10)
in an upper-surface (5) of the tray (3) that is otherwise flat within a peripheral
wall (4). The troughs (6) are of short lengths so that the walls (8) of the channels
(9) are interrupted to relieve frictional resistance against removal of the tray (3)
from the bottles (1) below, and in regions (11) are omitted altogether to allow the
tray to be lifted by suction pads. An orderly array of the bottles (1) in maintained
in spite of the lack of row-constraint on the tops of the bottles (1) where the channel
walls (8) are interrupted in both these ways, by virtue of abutment of the bottles
(1) upon one another within their rows and also between adjacent rows. As an alternative
(Figure 5), troughs are omitted other than along the sides (26) of the array and at
the ends of the rows (30). |
[0002] The invention is more particularly concerned with methods of stacking bottles or other articles, of the kind in which a plurality of arrays of rows of the articles are stacked one upon the other with each array standing on an upper-surface of an individual one of a plurality of trays in the stack, and in which restraint against lateral movement of articles out of their rows is exercised by engagement of tops of the articles with row-constraining walls configured in the under-surface of the tray which is immediately above in the stack.
[0003] Methods of this specified kind are described in GB-A-2257121 for stacking flasks and other bottles for safe storage and transport. The trays used in these methods are each of a thermo-formed sheet construction in which the walls of channels engaged on the under-surface by the tops of the bottles, are configured by elongate troughs in the upper-surface. The trays of bottles are stacked one upon the other with the bottom tray standing on a pallet and each of the others resting on the tops of the array of bottles beneath. A further tray is placed on the tops of the bottles of the uppermost array to complete the stack in preparation for bonding the stack together and to the pallet, using, for example, a plastics-film envelope thermally shrunk on.
[0004] It is one of the objects of the present invention to provide a method of stacking bottles or other articles, of the kind specified, that is of improved form.
[0005] According to one aspect of the present invention there is provided a method of stacking bottles or other articles, of the kind specified, wherein at least some of the walls constraining inner rows of the array are interrupted at one or more intervals along the lengths of those rows.
[0006] The present invention is based upon the realisation that it is not necessary for the tops of all the bottles or other articles of a row to be engaged with row-constraining walls of the tray above in the stack. It has been found that provided the tops of some of the articles of a row are engaged, and more especially the tops of the articles at either end of the row, adequate restraint against lateral movement can be achieved. This has advantage in connection with the unloading of the bottles or other articles from the stack.
[0007] Unloading of bottles from a stack is commonly carried out automatically either by sweeping the arrays of bottles from the trays of the stack in turn, or by lifting them individually all together from each successive tray. Once the bottles of the tray have been removed, the tray is itself removed by hand or machine to reveal the array of bottles standing on the tray below. With the form of tray used in the method of the present invention, as with the forms described in GB-A-2257121, removal of the tray requires it to be lifted before it can be moved to one side clear of the remainder of the stack. Lifting is necessary in order to break the engagement existing between the walls on the under-surface of the tray and the tops of the bottles beneath. However, in the case of the present invention, where the row-constraining walls are interrupted, the frictional resistance to disengagement is, in general, reduced as compared with what is experienced with trays of the form described in GB-A-2257121. The reduction in frictional resistance is of advantage in that disengagement is less likely to cause disturbance of the array when the tray is removed; it is also of especial benefit in reducing the effort required where removal is by hand.
[0008] The use of interrupted row-constraining walls is also, however, of particular advantage in the context of automated handling of the trays during both the loading and unloading processes. Automated handling of trays during loading and unloading is conventionally carried out using suction-pads that are brought down onto the upper-surface of the empty tray to lift it up under vacuum before swinging it onto, or, as the case may be, away from, the stack. However, conventional suction-pad equipment of this nature cannot be used successfully with trays of a sheet-moulded form such as described in GB-A-2257121, where the side-walls of the channels are defined by troughs moulded into the upper-surface of the sheet. The breaking up of the upper-surface with the troughs does not in general leave regions of flat surface that are extensive enough to allow the necessary suction-pad seal to be firmly established.
[0009] This latter problem can be readily overcome with the present invention, in that the invention facilitates the provision and use of a form of sheet-moulded tray having an upper-surface with one or more flat, unbroken regions of sufficient extent for suction-pad sealing. Regions of this nature can in this respect be readily created by choice of the locations and extent of interruptions in the row-constraining walls of the under-surface of the tray; troughs are simply omitted from the corresponding locations of the upper-surface. More particularly, a plurality of flat, unbroken regions suitable for suction-pad sealing may be provided spaced from one another across the upper-surface of the tray, simply by omitting troughing in those regions.
[0010] According to another aspect of the present invention there is provided a tray for retaining bottles or other articles in an array of rows of a plurality of such arrays stacked one upon the other with the array standing on an upper-surface of the tray and with tops of the articles of an array immediately below in the stack engaged with row-constraining walls configured in the under-surface of the tray, wherein at least some of the walls for constraining inner rows of the array are interrupted at one or more intervals along the lengths of the rows.
[0011] The upper-surface of the tray may be configured to divide that surface into parallel guideways for separating the rows from one another. These guideways may be defined between ridges that are upstanding from the upper-surface of the tray; such ridges may be interrupted where one or more flat regions, for example for suction-pad sealing, are required. Separation of the rows from one another using ridges or other means, is not, however, generally necessary where the articles of adjacent rows abut one another.
[0012] Methods of stacking bottles, and forms of tray used in such methods, all in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a schematic illustration of a stack of bottles such as constructed using a method, and involving five identical trays, according to the invention;
Figure 2 is a plan view, partly broken away, of one of the trays according to the invention, represented in Figure 1;
Figures 3 and 4 are sectional end-elevations of the tray of Figure 2 taken on lines III-III and IV-IV respectively, of Figure 2; and
Figures 5 and 6 are respectively a plan view and a sectional side-elevation taken on the line VI-VI of Figure 5, of a part of a second form of tray used according to the invention.
[0013] Referring to Figure 1, more than one thousand identical glass bottles 1 are loaded together on a wooden pallet 2 to stand upright with one another in five rectangular arrays of twenty-three rows each, that are stacked one upon the other. Five identical moulded-sheet trays 3 are included in the stack to locate and retain the bottles 1 together in the five arrays.
[0014] A tray 3 of the first, bottom array of the stack stands directly on the pallet 2 with the bottles 1 of that array standing upright on the tray 3, and with a tray 3 of the second array standing on the tops of the bottles 1 of the first. The bottles 1 of the second array similarly stand upright in their tray 3, and a third tray 3 of the next, third array stands on them. This stacking arrangement in which each successive array of bottles 1 stands in its individual tray 3 on the array beneath, is repeated for the third to fifth arrays. Five trays 3 are used for the five arrays; a sixth tray 3 (not shown) stands on the tops of the bottles 1 in the fifth, uppermost array, to top off the stack. The whole, including the pallet 2, is encased in shrink-film (not shown) to hold the stack tightly together as one for secure storage and/or transit.
[0015] Although this is not evident from the general schematic illustration of Figure 1, the bottles 1 in the specific embodiment of the invention to be described, are closely packed together on the trays 3 in staggered rows. The bottles 1 and their arrangement on the trays 3 are more appropriately represented in Figures 2 to 4.
[0016] Referring to Figures 2 to 4, each tray 3 is rectangular and has an upstanding peripheral wall 4. The wall 4 is configured to the bounding contour of the array of bottles 1 as they are loaded to stand against one another in staggered rows on the upper-surface 5 of the tray 3. The upper-surface 5 is flat apart from troughs 6 that run lengthwise of the rows. The troughs 6 configure the under-surface 7 to define side-walls 8 of channels 9 that extend in central register with the bottle-rows above.
[0017] Each channel 9 is closed at both ends and receives the tops of the bottles 1 of a respective row of bottles 1 of the tray 3 beneath in the stack. The ends of the channels 9 are defined by rounded troughs 10 (see Figure 2) in the upper-surface 5, and the side-walls 8 are flared out slightly to ease entry of the tops of the bottles 1 to the channels 9. The length and width of each channel 9 are chosen to be just sufficient to accommodate the tops of the bottles 1.
[0018] To the extent that the tray 3 has so far been described, it is of substantially the same form as that described with reference to Figures 6 and 7 in GB-A-2257121. However, in that case the side-walls of the channels in the under-surface of the tray are continuous, whereas in the present case they are interrupted. In this regard, each side-wall 8 of the tray 3 in the present case, is configured by an in-line sequence of short-length troughs 6 in the upper-surface 5. Moreover, the troughs 6 vary in length from one location to another. In particular, they are confined to parts of the upper-surface 5 which lie outside some eight or more circular regions 11 that are symmetrically spaced from one another across the upper-surface 5 of the tray 3. The flat, unbroken regions 11 of the upper-surface 5 are each of sufficient extent to enable good sealing contact to be established with the tray 3 by the respective suction-pads of tray-lifting equipment provided at a bottle-loading and/or unloading station.
[0019] As with the tray of Figures 6 and 7 of GB-A-2257121, the bottles 1 in each array are held firmly against movement within their own tray 3, but are also held fast with respect to other arrays in the stack by the interlocking of the trays 3 with one another through the bottles 1 on which they stand. The bottles 1 are held within their own tray 3 by the general confinement exercised at their bottoms by the surrounding wall 4, and, importantly, by the nesting channel-engagement of their tops with the tray 3 above them in the stack. Although the interruptions in the side-walls 8 of the channels 9 will leave the tops of some bottles 1 without full, or even any, channel-constraint, such bottles 1 are nonetheless found to be restrained adequately against movement laterally and longitudinally of their rows. They are held against lateral movement within the interruptions by abutment with the bottles 1 of the adjacent rows, and against longitudinal movement by such of the other bottles 1 in their same row that do have side-wall engagement.
[0020] It is desirable for good lateral confinement of the tops of the bottles 1 to ensure that the outermost wall 8 along each side of the tray 3 is free from any, or any significant, interruption. In the present case, short interruptions are provided for friction relief purposes; the troughs 6 by which the outermost walls 8 are configured in the under-surface 7 are indicated by the specific references 6' in Figures 2 to 4.
[0021] The tray 3 is thermo-formed from a sheet of high-impact polystyrene. The sheet, which for example, may have a thickness of 2 mm, is thermo-formed over a mould that conforms positively, with allowance for sheet thickness, to the configuration of the upper-surface 5 required.
[0022] The abutting and closely-staggered formation of the bottles 1 provided by the rectangular tray 3, allows diagonal- or slanting-row patterns to be identified in the array, as well as rows running lengthwise or widthwise. The channels 9 in the under-surface 5 may run parallel to any such pattern of rows.
[0023] The wall 4 need not be configured to conform to the outer contour of the array of bottles 1, but may be straight. Furthermore, the wall 4, rather than completely enclosing the upper-surface 5 of the tray 3, may be omitted from one end so as to allow for the bottles 1 to be swept from the tray 3 over that end, during unloading; clearly, the wall 4 in this case is desirably straight along at least the two longitudinal sides of the tray.
[0024] In the second method of stacking to be described, thermo-formed trays of the form shown in Figures 5 and 6 are used. With such trays, row definition on the under-surface of each tray is limited to the ends and outer margins of the tray.
[0025] Referring to Figures 5 and 6, the tray 23 has a peripheral wall 24 to its upper-surface 25, configured to the bottoms of the bottles 1 as they stand against one another in staggered rows. The upper-surface 25 is flat throughout, apart from a single line of short-length troughs 26 that run lengthwise of the tray 23 on each side just within the wall 24. The troughs 26 configure the under-surface 27 of the tray 23 to define side-walls 28 for restraining the tops of the bottles in the outermost rows, from lateral movement.
[0026] There is no channel definition on the under-surface of the tray 23 apart from at the ends of the rows; these ends are defined as shown in Figure 5 by rounded troughs 30 in the upper-surface 25. Thus, in this case, the tops of the bottles 1 are held in their rows at the ends of those rows, but apart from the confinement exercised laterally by bottle-upon-bottle abutment within the walls 28, there is no other restraint imposed laterally and longitudinally of the rows by the under-surface 27 of the tray 23. The absence of troughs throughout the whole of the upper-surface 25 apart from around the outer margin just inside the peripheral wall 24, ensures that good suction-pad sealing can be achieved with the tray 23 almost anywhere within the upper surface 25.
[0027] Support for the bottles 1 standing on the tray 23 is significantly dependent upon the support given by the tops of the bottles 1 on which the tray 23 stands; the flat, unbroken central area of the tray 23 will, in general, sag in the absence of this support from below. Thus, whereas the tray 23 is of a form suitable for use in providing the four intermediate trays (and possibly the top tray) of a stack constructed as illustrated in Figure 1, it may be found desirable to use a different form for the bottom tray standing directly on the pallet 2. If the same form is used, it is desirable to insert one or more packing pieces (eg of wood or plastics) beneath the tray to give support to the under-surface 27 between the walls 28.
[0028] The wall 24, instead of being configured to conform to the outer contour of the array of bottles 1, may be straight. In these circumstances, the rounded troughs 30 may be replaced by straight troughs corresponding to the troughs 26 and extending parallel to the ends of the tray. It will be appreciated furthermore, that a single trough may be provided just within the wall 24 to extend around all four sides of the tray 23.
1. A method of stacking bottles or other articles, in which a plurality of arrays of
rows of the articles (1) are stacked one upon the other with each array standing on
an upper-surface (5;25) of an individual one of a plurality of trays (3) in the stack,
and in which restraint against lateral movement of articles (1) out of their rows
is exercised by engagement of tops of the articles (1) with row-constraining walls
(8;28) configured in the under-surface (7;27) of the tray which is immediately above
in the stack, wherein at least some of the walls (8;28) constraining inner rows of
the array are interrupted at one or more intervals along the lengths of those rows.
2. A method according to Claim 1 wherein the articles (1) of adjacent rows of each array
abut one another such that where there are interruptions in the row-constraining walls
(8;28) for those rows lateral movement out of the rows is there restrained by such
abutment.
3. A method according to Claim 1 or Claim 2 wherein the walls (8) configured in the under-surface
(7) of the tray immediately above in the stack, define a multiplicity of closed-end
channels (9) for receiving the tops of the articles.
4. A method according to any one of Claims 1 to 3 wherein at least some of the trays
in the stack are of sheet-moulded construction and each has row-defining walls (8)
of its under-surface (7) configured by troughs (6,10) in its upper-surface (5), and
wherein interruptions of the walls (8) along the lengths of the rows define a plurality
of flat, unbroken regions (11) on the upper-surface (5) of the tray.
5. A method according to Claim 1 or Claim 2 wherein the walls (28) configured in the
under-surface (27) of the tray immediately above in the stack, are confined by the
interruptions to definition of sides of the array and closed-channel ends for the
rows.
6. A method according to any one of Claims 1, 2 or 5 wherein at least some of the trays
in the stack are of sheet-moulded construction and each has walls (28) of its under-surface
(27) configured by troughs (26,30) in its upper-surface, and wherein interruptions
of the walls (28) along the lengths of the rows define a flat, unbroken region bounded
by the troughs (26,30) on the upper-surface (25) of the tray.
7. A tray for retaining bottles or other articles in an array of rows of a plurality
of such arrays stacked one upon the other with the array standing on an upper-surface
of the tray and with tops of the articles of an array immediately below in the stack
engaged with row-constraining walls (8;28) configured in the under-surface (7;27)
of the tray, wherein at least some of the walls (8;28) for constraining inner rows
of the array are interrupted at one or more intervals along the lengths of the rows.
8. A tray according to Claim 7 wherein the walls (8;28) configured in the under-surface
(7) of the tray define a multiplicity of closed-end channels (9) in the under-surface
(7) for receiving the tops of the articles below.
9. A tray according to Claim 7 or Claim 8 of sheet-moulded construction wherein the row-defining
walls (8) of its under-surface (7) are configured by troughs (6,10) in its upper-surface
(5), and wherein interruptions of the walls (8) along the lengths of the rows define
a plurality of flat, unbroken regions (11) on the upper-surface (5) of the tray.
10. A tray according to Claim 7 wherein the walls (28) configured in the under-surface
(27), are confined by the interruptions to definition of sides of the array immediately
below and closed-channel ends for its rows.
11. A tray according to Claim 7 or Claim 10 of sheet-moulded construction wherein walls
(28) of its under-surface (27) are configured by troughs (26,30) in its upper-surface,
and wherein interruptions of the walls (28) along the lengths of the rows define a
flat, unbroken region bounded by the troughs (26,30) on the upper-surface (25).
12. A tray according to any one of Claims 7 to 11 having a peripheral wall (4;24) upstanding
from its upper-surface (5;25) for restraining lateral movement of articles on the
upper-surface (5;25).