GB2199559A - A device for drawing single flexible trays from packs of trays - Google Patents

Abstract

In order to pack confectionery, for example, trays of molded sheet material are used which have hollows. A device for destacking single trays from a stack (5) has a base (12) which coincides with the shape of the trays and projecting parts extending from it having a size coinciding with that of the hollows so as to create spaces between at least part of the surface of said device and the surfaces of the hollows in the tray. Suction holes communicate with said spaces and, if necessary, blower holes are provided to release the trays. The device is mounted on a support (26) which pivots between the stack of trays and a packing line on which the destacked trays are placed. The stack of trays is positioned on a magazine (44) between rods (48) and guides (50). Retaining elements (52) operated by rams (58) hold the forward trap behind the first tray on the stack in place. <IMAGE>

Description

A DEVICE FOR DRAWING SINGLE FLEXIBLE TRAYS FROM PACKS OF TRAYS In order to pack and wrap confectionery, such as chocolates, or other kinds of goods, use is currently made of trays or pallets of thin, flexible plastic material, molded into a shape having a plurality of compartments, each of which holds one item. These trays are supplied in packs or stacks, in which the trays are tightly inserted into one another and piled one on top of the other. In order to pack the goods, for example chocolates, a worker must manually separate the trays one by one and deliver each tray separately to the production line. This is generally considered an awkward and unpleasant operation because the trays generally have sharp edges. Furthermore, the trays stick tightly to each other and a certain amount of effort is required to separate them.

Lastly, some trays are likely to be distorted during this operation.

A suction apparatus is currently used for this purpose, comprising one or more suction cups mounted on an articulated arm; the apparatus picks up each tray by applying a vacuum in two or more localized points on the tray. With normal tray stacks, however, this apparatus does not yield good results in that, because the trays adhere closely to each other, the drawing action distorts the tray excessively, or removes two or more trays at the same time.

Special trays are therefore manufactured for use with this type of suction cup apparatus, said trays being provided with spacer ribs to separate the trays from one another and to leave an air space between them. These trays can be drawn quite easily, but when stacked they are excessively bulky, since the distance between adjacent trays is greater.

The aim of this application is to produce a tray drawing device capable of drawing each tray individually, without distorting it, from a compact tray stack.

This aim has been achieved with the device of this application, which comprises, on an articulated arm, a drawing element comprising a base and projecting parts which substantially reproduce, in a raised form, the shape of the hollow parts in a face of the tray, but are of such a size as to leave some clearance with respect to the hollow parts.

The base has a gasket along the surface of the edge facing the tray and has one, two or more suction holes; it also preferably comprises blower holes.

According to further characteristics of the invention, provision is made for a tray feed assembly and a retaining element, to hold back the other trays after the first one, while the first tray is being removed.

The new device is used by bringing the drawing element against the tray stack which is delivered face-up, until the projecting parts enter the hollows in the first tray to arrive and the gasket forms a seal against the flanged edge of said first tray. The vacuum applied is thus evenly distributed through the air space between the drawing element and the tray, on the inside surface of the latter, causing only imperceptible distortion of the whole surface, sufficient to detach the first tray from the next one.

The new device therefore permits reliable removal of the trays one by one, without appreciable distortion.

An exemplary embodiment of the invention will now be described, with reference to the attached rawings, in which: Fig. 1 is a perspective view of an unrestrictive example of a container tray for packing confectionery; Fig. 2 is a perspective view of a stack of container trays; Fig. 3 is a front view of a drawing element of the device; Fig. 4 is a top view of the element in figure 3 with a tray attached; Fig. 5 is a perspective view illustrating the device during a resting stage; Fig. 6 is a perspective view illustrating the device during the stage of drawing a tray; Fig. 7 is a perspective view illustrating the device during the stage of placing the tray on a packing line; Fig. 8 is an enlarged, broken perspective view of an element to retain the trays after the one which has been drawn.

With reference to the figures, a tray for packing goods, for example confectionery, is illustrated only as an example and is designated by 1 in Fig. 1; it is made of thin sheet material, generally plastic, and comprises a plurality of compartments or hollows, bordered by walls 3, and a peripheral substantially flat edge or flange 4. Trays 1 are currently available on the market in a wide variety of shapes and sizes, according to the goods they are to hold, and are normally supplied by the manufacturer in closely stacked piles, as illustrated by 5 in figure 2, in which the trays adhere tightly to one another.

The device according to this application, designated as a whole by 10 in the figures, comprises a drawing element 12, which has a substantially flat base 14 and projecting parts 16 with spaces between them, substantially coinciding with the hollows 2 in the tray as to number and generally as to shape, but of a slightly smaller size thah the hollows (as can be seen in figure 4). Base 14 extends beyond projecting parts 16 with a wide edge, on which gasketing material 18 is applied.

Base 14 has two openings 20 (obviously they could vary in number) which can be connected to a vacuum source; preferably, but not necessarily, a plurality of blower openings 22 are made through some projecting parts 16 for connection to a source of pressurized fluid.

Element 12 is supported, by means of brackets 24, on an articulated support 26, which comprises a transversal rod 28, held extended by an arm 30, mounted on an axle 32 which turns on the frame 34 of the device and is driven by means which are not illustrated. Rod 28 can be rotated around its own axis by means which are not illustrated, being of a known type. Element 36 serves as a guide for arm 30. Figures 6 and 7 show vacuum source connection tubes 38, connected to holes 20, and tubes 40 for connection to a pressurized fluid source connected to holes 22.

In figures 5, 6 and 7, number 42 designates a product packing line, which will not be described in detail herein, being of a known type.

Number 44 designates a tray magazine or feed assembly, substantially comprising, on a structure 46, inclined supporting rods 48 and lateral guides 50, set so that the width of the gap between them substantially corresponds to either the width or the length of the trays 1.

According to the present application, on a part of the end of each lateral guide is mounted a retaining element 52, consisting of a head 54 with projecting parts 55 alternating with guides 55', facing the trays. The space between the projecting parts is preferably equal to the distance between the trays in a stack. Head 54 is integral with a shaft 56 of a fluid operated cylinder piston assembly 58, of which numbers 59 and 60 designate the fluid inlet and outlet connections, for backward and forward movement of the head.

Operation of the device will now be described.

The device is fitted with a drawing element 12, of a suitable shape and size for the trays that are to be drawn, mounted on rod 28 (figure 5).

A stack 5 of trays 1 is positioned on magazine 44 (Figure 5) between rods 48 and guides 50, in such a way as to descend along them.

Retaining elements 52 are extended to retain the trays.

The articulated support 26- is then moved (Figure 6) to apply element 12 against and inside the first tray. This position of the drawing element and the tray is illustrated in figure 4, where it can be seen that there is a space between the walls of element 12 and-the walls of the tray. Elements 52 are withdrawn. Suction is applied through tubes 38 and holes 20. This is distributed in a substantially uniform manner along the air spaces between the walls of the drawing element and the walls of the tray, substantially over the entire surface of all these, so that the walls of the tray are slightly sucked in, so to speak, without distorting them appreciably, but detaching them from the walls of the adjacent tray, thus permitting air to be let in between one tray and the other so that the tray to be removed becomes detached.

Elements 52 extend and block the other trays after the first one.

Element 12, with a tray 1 held by suction, is then moved away from stack 5 and rotated (Figure 7) so that it places the tray on the packing line 42.

At this point vacuum is no longer applied and the tray is allowed to drop onto line 42. If required, this operation can be assisted by blowing air through tubes 40 and holes 22.

Claims (5)

1. A device for drawing single trays from a stack of trays, for use with trays made of molded sheet material with hollows to hold items, said device comprising a drawing element, a supporting and driving means for the drawing element, means for applying vacuum to said drawing element, characterized in that said drawing element comprises a base and projecting parts extending from said base shaped according to the shape of the tray to be drawn and of such a size as to create a space between at least part of the surface of said element and the surfaces of the hollows in the tray to be drawn, when it is positioned on the drawing element, said means of applying vacuum comprising holes in said element, which open into said space.

2. A device according to claim 1, characterized in that said holes are made in said base.

3. A device according to claim 1, characterized in that it comprises holes on at least some of the projecting parts, for connection to a blower system.

4. A device according to claim 1, comprising a tray magazine with an inclined plane, characterized in that said magazine comprises at least one retaining element consisting of a retractable rod bearing a head with alternating grooves and protruding parts.

5. A device according to what is described herein and illustrated in the attached drawings.