In printing shops, in order to carry out the operations of stacking or deviating the signatures, or similar products, it is necessary to split the continuous flow of these products so as to form finite groups of products which may be subjected to subsequent processing.

This operation is at present carried out by using a barrier which goes down on the conveyor means holding back the products.

Another used technique is gripping, which consists in gripping the signatures in the desired point allowing the signatures preceding said point to advance and to create a space between thelatter and the stopped ones.

These two known techniques have the disadvantage of slowing down the production. As a matter of fact, when using these techniques, the space between groups of products increases according to the time during which the barrier is down on the scaly conveyor, or to the stop time due to the gripping. However, the greater this period of time, the greater the accumulation of the products against said stop systems. This accumulation makes it difficult, and in many cases impossible, to carry out the subsequent stacking or processing operations. The difficulties increase as the thickness of the conveyed products and the transportation speed increase. Therefore, the production speed must be decreased to make the products processing or the stacking possible.

In order to overcome said drawbacks, the Italian patent n. 1.317. 547, in the name of the same applicant, discloses a device for separating or extending a scale of products provided with means suitable for increasing the speed of the conveyors which transport, the separated or extended scale with respect to the speed of the conveyors which transport the scale upstream of the separation or extension.

This device, however has considerable construction difficulties apart from

being very expensive.

The object of the present invention is therefore to provide an apparatus for splitting a series of products in scaly overlap free from the above-mentioned drawbacks.

This object is achieved with an apparatus whose main features are specified in the first claim. The further features are specified in the subsequent claims.

A first advantage of the apparatus according to the present invention lies in the increase of the production speed. Furthermore, this apparatus does not cause accumulation of products.

Another advantage of the apparatus according to the present invention lies in that it is cheap and simple to manufacture.

These and other advantages of the present invention will be clear to those skilled in the art from the following detailed description of an embodiment thereof with reference to the attached drawings wherein: figures 1, 2,3 and 4 show diagrammatic side views of the apparatus according to a first embodiment of the present invention in consecutive steps of the operative cycle; figure 5 shows a diagrammatic plan view of the apparatus of figure 1 at the beginning of the operative cycle ; and figure 6 shows a diagrammatic side view of the apparatus according to a second embodiment of the present invention.

Referring to these figures there is seen that the apparatus for splitting a series of products in scaly overlap, according to the present invention, comprises a conveyor 1 which, in a preferred. embodiment, consists of a pair of conveyor belts 2 whereon products 3 are scaly arranged. Conveyor 1 is driven by a motor 4 connected to belts 2 by means of motion transmission components 5, such as belts and pulleys, in order to transport products 3 in the direction indicated by arrows F.

Said conveyor 1 is adjacent to a second conveyor 6 consisting of conveyor belts 7 whereon products 3 coming from conveyor 1 are transferred. Also conveyor 6 is provided with a motor 8 for the operation thereof and conveys products 3 in the stacking area 9.

Above conveyors 1 and 6 there is arranged a blocking device 10 suitable to perform the splitting of the continuous flow of products 3 in scaly overlap into groups of products 3. This device 10 comprises a fixed support 11 and a mobile frame 12 which slides thereon thanks to a chain 13, or another transmission means, driven by a motor 14 through a belt 15. Said chain 13 is provided with a pawl 15'which, engaging a groove formed in the mobile frame 12, drives it to slide with reciprocating motion on the fixed support 11. On'said mobile frame 12 there is fixed a piston 16 controlled by an electrovalve or by an equivalent means.

The rod 17 of said piston 16, coming out from its housing, causes the lowering of a thin plate 18, fixed under the bottom surface of the mobile frame 12, on products 3.

Under said surface of the mobile frame 12 there is also hinged a rod 19, of length variable according to the size of the transported product, which has at its end two pulleys 20,21 whereon an upper belt 22 for accompanying products 3 runs. Said belt 22, which runs on products 3, is driven by the same motor 8 which drives the second conveyor 6.

Said pulleys 20,21, being integral with rod 19, and thus with the mobile frame 12, are mobile. Belt 22 runs also on other pulleys 23,24 fixed respectively at the stacking area 9 and at the fixed support 11.

The apparatus, according to a preferred embodiment of the present invention, is provided with a bearing bar 25 placed under conveyor belts 2 and 7 in the area wherethe thin plate 18 is lowered on products 3 so as to form therewith a mobile gripper.

In a second embodiment of the present invention, shown in figure 6, the bearing bar 25 is replaced by a belt 26 or by a chain driven by motor 14 through transmission components 27.

In a third embodiment not shown in the drawings, the two conveyors 1,6 are replaced by a single conveyor which accompanies products 3 up to the stacking area 9.

The operative cycle for splitting the flow of products transported in scaly arrangement according to the preferred embodiment of the present invention is

described hereunder.

When it is necessary to split a flow of products 3 transported in scaly arrangement on conveyor belt 2, motor 14, preferably by means of an electric control, and piston 16, preferably by means of a pneumatic electrovalve, are activated. Rod 17 of piston 16 comes out from its housing causing the lowering of the thin plate 18 on products 3, as shown in figure 2. Thelatter are thus blocked between said thin plate 18 and the underlying bearing bar 25 or belt 26. Piston 16 is integral with the mobile frame 12 of device 10 and therefore it slides therewith on fixed support 11.

Then the mobile frame 12 is put in motion by motor 14 which, through the transmission components 15, drives chain 13.

The mobile frame 12 starts to move horizontally on fixed support 11 in the same direction of conveyor 1 with a speed equal to or lower than the speed of the latter. Conveyor 1, in turn, has a speed equal to or lower than that of conveyor 6.

In particular, if mobile frame 12 has a speed lower that that of conveyor 1, the speed of conveyor 6 may be equal to or higher than that of conveyor 1, according to the operative needs. On the contrary, if the speed of the mobile frame 12 and that of conveyor 1 are equal, the speed of conveyor 6 must necessarily be higher than that of conveyor 1 for achieving the splitting of the series of products 3.

With this system of speed regulation, products 3 which are upstream of the blocked product 3 can proceed along their direction without bunching one on the other, yet decreasing their relative distance and thus the so called"scale pitch".

Products 3 which are downstream from the blocked product 3, continue their motion on conveyor belts 7 of conveyor 6, helped by upper belt 22 which, pushing these products 3, prevents them from being trapped under the blocked product 3.

In this way there is formed a progressive space between the signature downstream from the blocked product 3 and those upstream thereof, as shown in figures 3 and 4, which will be as much greater as greater is the difference between the speeds.

Pulleys 20 and 21 arranged at the end of the adjustable rod 19 are placed, through the rod 19 itself, at a distance from the rod 17 of the piston l6, and thus from the end of the thin plate 18 in the gripping position, equal to or slightly

greater than the length of product 3 so that the upper belt 22 pushes the product 3 immediately downstream from the blocked product 3 toward the stacking area 9.

As the mobile frame 12 moves toward the stacking area 9, the length of the portion of belt 22 comprised between pulleys 24 and 21 increases, whereas the length of the portion of the same belt 22 comprised between pulleys 20 and 23 decreases. In this way the total length of belt 22 is constant and therefore it is not necessary to subject to tension any element of the apparatus, nor to use particular materials to manufacture belt 22.

When the mobile frame 12 comes to the stop, rod 17 of piston 16 moves back into its housing allowing the thin plate 18 to rise thus releasing the product 3 which had been blocked. At this point products 3 start to move again at the speed of conveyor 6 towards the stacking area 9. The mobile frame 12 reverses the direction of motion and moves back to the initial position shown in figure 1, ready for a new cycle.

It is obvious that the embodiments of the apparatus according to the present invention described and illustrated above are only examples susceptible of numerous changes. In particular it is possible to obtain the translation of the mobile frame 12 by means of a pneumatic or hydraulic piston, a screw or belt drive, a rod-crank system, a pinion-rack system or a reciprocating motion motor.

It is also possible to use, for the motion of belt 26, the pressure which rod 17 of piston 16 exerts on products 3 when pressing thereon through the thin plate 18.