Installation for stacking plate-like elements

Abstract: In an installation for stacking plate-like elements (4), in particular fibre plates, supplied on an infeed conveyor, a compact construction and rapid and reliable processing are obtained by a controlled level switch (14) which takes an infed element (4) into one of a number of buffer stations (24, 26) which are situated above one another, with downstream thereof a stacking station with a number of stacking units (38, 40) situated above one another, each with a controlled removable support (30, 42), and below them a receiving support (49) on which the elements, falling over a short distance, land.

Description: The invention relates to an installation for stacking plate-like elements, in particular fibre plates. An installation for stacking light plates such as glassfibre plates , is known in practice. It comprises two elongated cylindrical receiving elements, the axes of rotation of which lie parallel to the infeed direction of the plate-like elements, in each of which elements a part bounded by two radial faces is recessed, and which elements are situated above the receiving table on which the plates are to be stacked. An infed plate ultimately lies with each of the two opposite end edges in the recessed cylinder part; as soon as the plate has come to a standstill, the two cylinders are turned through a quarter turn in opposite directions, with the result that the plate is ejected downwards. The disadvantage of this known stacking installation is that receiving each infed plate, slowing it down and bringing it to a standstill, followed by rotating the two receiving cylinders through 90° takes a certain amount of time, which, of course, limits the infeed speed of the infed plates. If the speed at which individual plates are manufactured is greater than the speed at which the plates for stacking with this known installation can be processed - which is particularly the case with glassfibre plates - the infeed conveyor has to be divided into two or more partial conveyors situated behind one another, each ending in a stacking station of the type described above. It is clear that this not only results in an expensive plant, but also considerably increases the overall area taken up by the plant. The object of the invention is to overcome these disadvantages and to this end provides an installation as known from EP-A-0 688 730 to which the preamble of claim 1 refers, which installation is primarily designed for stacking box-shaped articles but which, when modified as indicated in the characterizing clause of claim 1, becomes excellently suited for high-speed stacking of light-weight plates, particularly glass fibre plates. The plates are very well supported over their entire path, even at high speed, and donot deviate from their path, so that the end result is an excellent stacking with a high productivity. Preferred embodiments of the installation are described in claims 3 to 6 inclusive. The measure according to claim 2 has the advantage that there is always a force directed in the desired direction of movement acting upon the plate-like elements. By the measure according to claim 4 the plates will have, already prior to reaching the level switch, a certain mutual distance, with the result that further processing is made easier. The measure according to claim 5 will preferably be used if the installation according to the invention is at the end of a high speed production line (such as that for glassfibre plates) so that plates are fed-in during the time needed for discharging a completed stack. Finally, the measure according to claim 6 reduces the overall length of the installation in the direction of conveyance. DE-A-3 736 868 shows a stacking device for packets comprising buffer stations but without a level switch, while DE 2 44 3781 describes a stacking device for corrugated paper plates with two, mutually independent supply conveyors, one above the other and each with its own stacking station. The invention is explained with reference to the drawing, in which: Figs. 1a and 1b show in combination and diagrammatically a side view of an embodiment of the installation according to the invention; Figs. 2a and 2b show in combination and diagrammatically a top view of this installation. The installation according to the invention is intended for placing downstream of a production line 2, in which plates 4 are formed from a continuous web of starting material, for example fibre material such as glass wool, by cutting parts off said continuous web at right angles to the direction of travel indicated by the arrow 6. In an accelerating roller conveyor 8 the plates 4 reach a higher speed than that at which they were travelling on the production line 2, so that the successive plates acquire a greater mutual distance, as indicated in the figure for the plates 4a, 4b, 4c. By way of two conveyors 10 and 12 connecting to each other, and known per se, the successive plates arrive at a level switch station 14, consisting of a driven endless belt 16 which is guided around the guide rollers 18 and 20. The driving guide roller 18 is in a fixed position, but the guide roller 20 can be moved up and down in a controlled manner in the direction of the arrows 22, with the result that the infed plates, such as the plate 4b, can be taken to one of two different levels, indicated by N1 and N2. The plate buffer station 24 connects to the level N1, and the plate buffer station 26 connects to the level N2. Each of the buffer stations 24, 26 has a very special construction. Each station comprises (see in particular Fig. 1b) a first set of endless belts 28 situated next to each other and at a distance from each other, combined with a second set of endless belts 30, likewise situated at a distance from each other, in such a way that a belt 30 always lies between said belts 28, so that the top surfaces of the belts 28, 30 lie in one plane. The belts 28 are driven around, as are the belts 30, but both for the bottom buffer station 24 and for the top buffer station 26 the latter belts are accommodated in a frame 31 which can be moved to and fro in the direction of the arrows 32. The direction of movement of the belts 28 and 30 is in the direction of the arrow 33 -thus in the direction of travel of the plates illustrated - and the peripheral speed of the belts 30 in this direction is higher than the speed at which each frame 31 with the belts 30 can be moved in the direction opposite to that of the arrow 33 (i.e. to the left) so that, even if a frame 31 with the belts 30 is moved back, a resulting driving force in the direction of the arrow 33 always continues to be exerted on a plate resting on the belts. Each station also has a controlled stop 34, 36 which can be taken into the path of the plates, by means of which stop an infed plate, such as the plate 4c, can be stopped. A bottom stacking unit 38 and a top stacking unit 40, each with a controlled, symmetrically removable plate support, connect to the two buffer stations 24 and 26 respectively. This support is in the two stacking units 38, 40 formed by, on the one hand, the movable belts 30 in the frame 31 of the upstream buffer station 24, 26 and, on the other hand, by a set of belts 42 which are fitted symmetrically relative thereto and are movable to and fro relative thereto, and which are driven around in the direction of the arrow 44 and accommodated in a frame 45 which is movable to and fro. Each stacking unit 38, 40 also has a fixed elongated plate stop 46. When sets of belts 30, on the one hand, and 42, on the other hand, are moved away from each other, a plate lying thereon is ultimately no longer supported and consequently falls down. So long as they bear a plate lying thereon, the belts 30 will always continue to exert a force on said plate in the direction of the arrow 33, i.e. to the right in the figure - even if they are moved with their frame 31 to the left - and this also applies to the belts 42; this means that a supported plate will always remain pressed positively against the stop 46 until the belts 30, 42 ultimately release said plate. An additional buffer is fitted below the two stacking units 38, 40, said buffer consisting of two supports 48a, 48b which are movable to and fro and, being movable in the horizontal direction, can be taken into the vertical path of the plates falling down; they can be designed in such a way that they can be moved downwards stepwise as the number of plates resting thereon increases. Situated below that is a receiving table 49 which is movable in the vertical direction and has two conveyor belts 50, 52 for discharging a completed stack 56 in the direction of the arrow 54 or in another direction, for example perpendicular to the plane of the drawing. Of course, this table will initially stand in the highest position and, as the stack of plates thereon grows, it will be moved downwards. The installation operates as follows: The individual plates, situated at a distance from each other, are, in line with each other, and thus successfully fed to the level switch station 14 which feeds the plates alternately to the buffer stations 24 and 26 respectively; in each of said stations a plate, such as the plate 4c, comes to rest against the stop, such as the stop 36. When the stacking unit adjacent to a buffer station has released a plate, the control (not shown) makes the frame 31 with the belts 30 move to the right and the frame 45 with the belts 42 move to the left; the stop 34, 36 is then released and the plate present in front of it slides, still fully supported, to the right until it is against the stop 46. If both stacking units 38, 40 contain a plate, the supporting belts 30, 42 of the top stacking unit are first drawn back, and the top plate 4d falls onto the bottom plate 4e; bottom belts 30, 42 are then drawn back, and both plates fall down together onto the stack 56 which is forming. During the formation of this stack 56 the support 48a, 48b is opened. If the production process is a continuous, very rapid process, the supports 48a, 48b are temporarily taken into the vertical falling path of the plates during the discharge of a completed stack in the direction of the arrow 54, so that an intermediate stack is temporarily formed. A stack with an even number of plates is formed in the manner described. Of course, with a suitable control of the buffer stations 24, 26 it is also possible to form stacks with an uneven number of plates.

Claims: Installation for stacking plate-like elements (4), in particular fibre plates, comprising an infeed conveyor (10, 12) supporting the elements, a controlled level switch (14) comprising a conveyor (16) guided around two guide rollers (18, 20) at a distance from each other, the downstream end of the conveyor being (20) rotatable in a vertical direction about the axis of the guide roller (18) at the infeed side, which connects to the infeed conveyor (10, 12) and by means of which an infed element (4b) can be taken into one of a number of buffer stations (24, 26) which connect to the level switch (14) and which are situated above one another, from which each buffered element (4c) can be transferred in a controlled manner to a stacking station with a number of stacking units (38, 40) above one another, each connecting to one of the respective buffer stations (24, 26), and each with a controlled removable support (30, 42), and having therebelow a receiving support (49) for a completed stack (56) of elements, the installation being controlled in such a way that when infed elements are conveyed by way of the level switch alternately to the respective buffer stations (24, 26) and from there to the respective stacking units (38, 40), the respective removable supports (30, 42) of the latter release the elements successively, characterized in that the element support in a buffer station (24, 26) is formed by first (28) and second (30) endless belts placed alternately next to each other and driven around, the second belts (30) of which are accommodated in a frame (31) which is movable to and fro in the direction of conveyance and by means of which the plate-like elements can be taken into the adjacent stacking unit (38, 40) where the second belts (30) co-operate to support a plate-like element with third endless conveyor belts (42) which are driven around and can be moved to and fro symmetrically relative to the second belts, each buffer station being bounded by a controlled removable stop (46) for the infed elements. Installation according to claim 1, characterized in that the circumferential speed of the second belts (30) in their frame (31) is higher than the speed of said frame during the return movement thereof. Installation according to claims 1 - 2 characterized by two buffer stations (24, 26) and stacking units (38, 40). Installation according to claims 1 - 3 characterized in that the infeed speed in the infeed conveyor is higher than same of a preceding production line in which the plates are cut off a continuous and coherent product strip. Installation according to claims 1 - 4, characterized by a controlled plate support (48a, 48b) situated between the stacking units (38, 40) and the receiving support (49), and forming a vertical buffer station. Installation according to claims 1 - 5, characterized by a stack discharge installation which works in a direction at an angle to, and preferably perpendicular to, the direction of conveyance.

Inventors: BORS CORNELIS JOHANNES MARIA, BORS, CORNELIS JOHANNES MARIA
Applicants: BORAL B V, BORAL B.V.
Application year: 1997
Main classification: B65G57
IPC codes: B65G57