EP0058140A1

EP0058140A1 - An automatic apparatus for forming and ejecting piles of sheets at high speed

Info

Publication number: EP0058140A1
Application number: EP82830024A
Authority: EP
Inventors: Giampiero Giusti
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-02-05
Filing date: 1982-02-04
Publication date: 1982-08-18
Also published as: ATE16092T1; IT8147737A0; IT1142289B; EP0058140B1; DE3266885D1

Abstract

Automatic apparatus, wherein each of the exits (2, 3; 4, 5) of the cutter (1) of the upstream producing machine presents a conveying plane (6; 23) for the sheets, pivoted at the upstream end and feeding, at its downstream end, which oscillates vertically, two fixed roller planes (9, 10) apt to unload in turn the sheets on a subsequent raising device (13, 14; 32, 33), so that, once the piling has been completed on one of said roller planes (9, 10), while it unloads on said raising device (13, 14; 32, 33) said conveying plane (6;23) feeds the second roller plane, which then will unload the sheets on the raising device (13, 14; 34, 33) which has emptied and has been brought in the meantime at the level of this roller plane (9; 10) and so on. The apparatus is capable of operating even with a number of said roller planes (9; 10) different from two or with a roller plane (9; 10) replaced by a receiving plane (41, 42), vertically movable.

Description

This invention is concerned with an automatic apparatus for forming and ejecting at high speed piles or groups of sheets formed of any whatsoever material, as in particular paper, cardboard, corrugated cardboard, plastic material and the like.
More particularly, in the field of production of corrugated cardboard certain specific requirements must be followed between the exit of the corrugating machine or corrugator (from which sheets of corrugated cardboard are ejected in a continuous and automatic way, one after the other) and the stacking device or final collector, (that is the device wherein said sheets are stacked).
Very recently there has been a very conspicuous technological evolution in corrugating machines, that is in the parts of line production upstream with respect to the final collectors, whereby speeds of the corrugating line much higher than those presently obtained are in view.
The most relevant innovations have been applied to cutters (that is the devices by means of which the continuous webs of corrugated cardboard, produced by the corrugators, are cut in the longitudinal direction and in the transversal direction to a particular size): the traditional type of mechanically controlled cutter has been replaced by a type operated through a direct control with a motor controlled by a calculator, from which a pratically instantaneous setting of measure and a perfect control on the cut are obtained, thus permitting higher speeds. In even more recent times, a further generation of cutters has developped, equipped with "oyerspeed" motors, which, by advancing the rotation, allow to further increase the speed, especially with reference to sheets of short size for which the speed of rotation of the cutter is so high that it imposed a limit for the control of the cutting lengths. These innovations pertaining to cutters, combined with the improvements of the corrugating machines which would have allowed higher speeds of production of the corrugated cardboard, have resulted in a strong increase in the speed of production and in a better control of the length of the sheets and therefore in a reduction of rejects, due to mistakes in such lengths A fundamental problem pertaining to these apparatus consists however in the necessity of reducing the so-called idle times, especially in the presence of a European market characterized by the noticeable differences of the order related to the size of the cardboard sheets, which makes it necessary to frequently change the setting of the cutters, as a function of the change of order, which under traditional conditions involved the stopping of the machine and then the resuming of the production. The elimination of the idle times would allow to use a so-called "non-stop"system deriving from the exploitation of the possibilities offered by said recent types of cutters operating on a direct control basis.
The present technology promises therefore for the future to be able to pass from one order to another (that is from one format to the other) in speed,'without stopping the machine.
All these technological evolutions have on the other hand accentuated certain limitations and deficiencies of the traditional stacking systems, which if a few years ago were acceptable at the operating speeds of the upstream systems, today clearly appear as being insufficient, especially as far as short formats are concerned.
The gathering devices are traditionally laid out so as to gather the-sheets of cardboard as these leave the cutter; there being the necessity of having to switch such sheets to a collecting and raising device and therefore of stopping or slowing down the belt conveyor along the conveying plane at the exit of the cutter, in coincidence of such exit or along the conveyor itself an accumulation of cardboard necessarily will form (with consequent inconveniencies, which will be described further on),said accumulation being all the more considerable as the upstream production rate increases, as the format is shorter, and as the period of time of stopping or slowing down of said belt conveyor is longer and the cardboard is thicker.
Another problem, not yet solved, is that which occurred when, using the above mentioned non-stop production line, it was required to instantaneously pass from one format to another, since it appeared to be impossible to obtain a subdivision of the two formats along the conveyor, said subdivision however being necessary in -order to separately switch the two cardboards of different formats.
The object of this invention is therefore that of eliminating the above mentioned inconveniences and limitations of the prior art, as will appear clear from the following description.
It has already been stated that the concept up to this day was that of gathering the cardboard sheets at the exit of the cutter, and the necessity of stopping or slowing down the belt conveyor has been already discussed; in order to outline the problems more clearly, in the following description reference will be made to the example of "an ejection of groups of sheets", in which case the problems do in fact become more macroscopic with respect to the ejection of a complete pile or stack: in fact a standard group of sheets is formed by corrugated cardboard sheets one over the other so as to form a height of about 30 cm, whereas a complete pile or stack is formed by corrugated cardboard sheets one over the other so as to form a height of about 1.5 meters; it is therefore evident that in the case of an ejection in groups of sheets, five ejections will be required in order to eject the same quantity of cardboard corresponding to a single ejection of a complete stack. Usually, said conveyor belt feeds the cardboard sheets onto a roller plane which is vertically movable; in other words it lowers progressively, under the control of a photocell, until, when the group of sheets has reached the desired height, a stopping member closes whereby the flow of cardboard is interrupted and therefore the conveyor belt stops, in order to allow for enough time to carry out two functions: the first consists in the fact that the roller plane must lower'to an ejection level and then must raise again up to a receiving level; the second consists in the fact that, once said ejecting level has been reached, the rollers of said roller plane must carry out the ejection on gravity roller planes placed downstream. This cycle requires about three to four seconds for the descent, about three to four seconds for raising again, and about seven to nine seconds for the ejection, for a total of about fifteen to seventeen seconds, during which the plane of the conveyor belt is necessarily stopped while on said plane the cutter in full speed continues to eject the cardboard sheets, therefore determining the necessity of solving the problem of a temporary storage of the sheets on said plane.
Now it is evident that being said stopping time a fixed time (it, as it has been seen, is required by the indispensable operating times for the said functions of descent, raising and ejection), the speed of production at which the corrugator may be made to operate will depend on the maximum admittable quantity of sheets which may be accumulated on the conveyor plane during the period of time of its stopping, since, going beyond said quantity, insurmountable problems of congestion would be caused at the discharge from said conveyor plane as
soon as the latter is placed back into movement, therefore creating a machine block; finally, this involves the necessity of strongly slowing down, during said fifteen to seventeen seconds, the production rate of the upstream corrugator, with an obvious decrease of the total efficiency of the productive cycle, such slowing down having to be all the more conspicuous as the thickness of the cardboard increases and as the length of the sheets decreases.
According to the invention such operating concept has been radically changed: according to the invention, in fact, at the exit of the cutter-, or of a machine which continuously feeds sheets, the conveying plane is in a fixed position; furthermore it continues to transport and eject the sheets in a practically continuous way or at the most with an extremely short interruption of the order of three to five seconds, whereby, even at the maximum operating speeds, today technically possible, of the upstream machine, for example of a corrugator, the condition will never be reached of piles or layers being produced on said conveying plane in such a quantity that the following discharge is jeopardized.
The invention also enables to solve the problems which would be created downstream, and this through substantially the complete elimination of the above mentioned idle times related to said cycle phases (descent, raising and ejection); in fact, the conveyor plane (which is, as previously stated, fixed in the vertical direction, at its front or upstream end, being pivoted in such end and being able to oscillate vertically at the other end, that is downstream, is apt to feed two or more fixed roller planes or the like, arranged one over the other, at a distance in height.
In such a way the roller plane, being fixed, is capable of ejecting without having to carry out the above mentioned movements of descent and raising, whereby the first idle time is recuperated, that is that which in the apparatuses used to this day was necessary for the descent and raising of the roller plane; there being also provided as previously stated another roller plane, also said ejection time is recuperated, since as soon as the desired group of sheets is completed on the first roller plane and while the ejection thereof begins, the conveyor plane having moved with its downstream end to the level of the second roller plane, begins immediately to supply the latter; on the outside of the two roller planes, an elevating plane, while one of the two roller planes is being fed, will receive the group of sheets from the other roller plane, and will unload it, in order to move immediately thereafter to the level of the roller plane mentioned first, to receive therefrom and distribute the discharged material.
All this allows, according to the invention, to reduce the total time of stopping of said conveyor plane to only about three to five seconds against the fifteen or more seconds, related, as previously stated, to the prior art (such time of stopping is reduced practically only to that related to the closure of the gate which will be discussed further on, to the ejection of the sheets underlying same and to the passage to the empty roller plane) and therefore allows an operative rhythm of the corrugator not only continuous but also conducted at the highest speeds of corrugator today already possible, and increasable even more in future years.
In the event that upstream a machine is present which is not capable of very high operating speed, only the partial recovery will be sufficient of the idle times; instead of two fixed roller planes it will be possible to have one single fixed roller plane at ejection level, in order to supply it through said oscillating belt; in this case only said time of descent and rising is recuperated instead of recuperating also the ejection time of the groups of sheets from the roller plane, that is instead of a gain of fifteen to seventeen seconds a gain of six to seven seconds will be obtained. In any case, no matter what the number of said fixed roller planes, that is even if only one is provided, this .invention involves the following very important advantage: on the conveying plane, which is fixed upstream and oscillating vertically downstream, during the short time of stopping of unloading of the sheets therefrom, the temporary accumulation or storage of the sheets which are ejected without solution of continuity from the upstream machine which may continue, as seen, to work at full speed, will take-place not on the upstream end of the conveying plane, as in the prior art, but on the downstream end, that is against said gate; the conveyor belt actually is stopped, as previously stated, only a few momentsfor ejection of the last sheets, in order to complete the stack;during all the later time of unloading-of the already prepared stack from the roller plane up to the reopening of the gate, the belt is not stopped but is in movement, therefore accumulating the sheets against said gate. Accumulation of the sheets against the gate present the following advantages: a height of the stacks more uniform (in fact, on the empty roller plane the formed accumulation is always put first); the drawback is eliminated which derives from the fact that in cycle moments the situation would occur, in the phases of completion of the stack,-of ejecting an accumulation of sheets which has formed upstream at the exit of the cutter; the fact that the belt is in movement during unloading of the stack from the roller plane up to the reopening of the gate allows by reflex also a continuous scaling of the sheets along the conveyor belt,starting from the exit from the cutter. The simple pivoted mounting of the conveyor plane at its upstream end also achieves a considerable simplification in construction with respect to conveyor planes of the prior art, movable at both their ends by means of a double suspension thereof.
The change of order that is of the format involved, in the prior art, another inconvenience: the roller plane receiving the sheets from the conveyor plane is provided with a movable aligning wall, against which the sheets are aligned during the formation of the stack; such wall as the format is changed must be moved every time in coincidence of the new measure; therefore, in the prior art, with a stopped conveyor plane, in addition to the above mentioned idle times of descent and raising and ejection, a further idle time was inevitable, that is that related to the movement of said wall for the new format. According to the invention, while the group of sheets of the previous order is being formed on one of said two roller planes, at the same time a new measure is set for the wall on the other roller plane, so that as soon as the ejection begins from the first roller plane, the other roller plane may begin to be fed with the new order, without solution of continuity and saving in fact said further idle time which would have been necessary for the new setting of said wall; the physical space present between the old format and the new one on the conveyor..plane in movement, is easily traced with any instrument;. this solution solves therefore also the important problem of the non-stopping, that is of the change of order at full speed.
According to a variation of execution, the conveyor plane may feed, instead of as previously seen fixed roller planes, a vertically movable roller plane; even in this case, the arrangement is such as to allow a considerable saving of idle time with respect to the case of a vertically movable receiving plane which cooperates with a conveyor belt which is fixed at the downstream end, since, as will be better seen further on, the time of rising of the receiving plane is practically reduced to the half, since at the same time the conveyor belt lowers.
The apparatus according to the invention is therefore in substance characterized by the fact that, at one or more exits of a continuous feeding machine of sheets, it comprises: conveying means, pivoted exclusively at their upstream end so as to be able to vertically oscillate at their downstream end; one or more receiving planes vertically fixed, arranged one over the other vertically at a distance, or one receiving plane vertically movable, fed by the
downstream end of said conveying means, said planes being provided with motor driven means such as rollers, belt conveyors or the like, said vertically fixed planes, in the case where there are two or more, cooperating with raising means, arranged downstream thereof, translatable vertically from one to the other of the levels thereof, and provided with motor driven means such as rollers, belt conveyors or the like; and photocell means or the like, which as a function of the height of the stack which has formed on said planes, control the raising of the conveying means which cooperate with said one or more fixed receiving planes or control the lowering of said movable receiving plane and the subsequent raising of the related conveying means, there being provided gate means, which, after having ejected the last sheets arriveithereto, temporarily close the feeding of the sheets from the conveying means to said planes, said gate means being arranged at
the downstream end of the conveying means and being controlled by a limit switch thereof, there also being provided usual control means for stopping the operation of tne conveying means only for the extremely short time of tne step of ejection carried out by said gate means, and for automatically synchronizing all the various operating phases of the apparatus, in particular the ejection of the sheets from the receiving planes, the re- opening of the gate means, the ejection of the sheets from the raising means and the translation of the latter up to the right level.
The characteristics and advantages of the invention will however appear more evident by the following detailed description of form of embodiment thereof given by way of example and not to be intended as being limiting, with reference to the enclosed drawings, in which:

figure 1 is a schematic representation in side elevation of a first form of embodiment of the apparatus according to the invention with some parts not shown;
figure 2 is a schematic plan representation of figure 1, with parts not shown in the latter and with parts broken away;
figure 3 is a schematic cross-section according to plane III-III of figure 2;
figure 4 is a schematic cross-section according to plane IV-IV of figure 2;
figure 5 is a schematic side elevation view of a second form of embodiment according to the invention, with some parts not shown;
figure 6 is a plan schematic representation of figure 5, with parts not shown in the latter and with parts broken away;
figure 7 is a schematic cross-section according to plane VII-VII of figure 6;
figure 8 is a schematic representation in side elevation of a third form of embodiment of the present invention, with some parts not shown;
figure 9 is a plan schematic representation of figure 8, With parts not shown in the latter and with parts broken away;
figure 10 is a schematic representation according to plane X-X of figure 9; and
figure 11 is a schematic cross-section according to plane XI-XI of figure 9.

With reference first to figures from 1 to 4, the usual terminal part of the machine for production of sheets, that is, in the specific case, of the corrugator which in a continuous manner produces sheets of corrugated cardboard has been indicated in 1. Within said terminal part 1 the cutting device or cutter operates, with which the continuous webs of corrugated cardboard produced by the corrugator are cut at high speed in the longitudinal direction and in the transversal direction into the proper format. The cardboard sheets are ejected in a continuous manner from a lower exit (that is from the interstice between the upper branch of the belt conveyor 2 and the lower branch of the belt conveyor 3) and from an upper exit (that is from the interstice between the upper branch of the belt conveyor 4 and the lower branch of the belt conveyor 5).
The sheets from the lower exit 2, 3 are fed at high speed, in a scaled arrangement, onto a conveying plane 6, _'formed by the upper branch of a belt conveyor; the plane conveyor 6 is pivoted on a horizontal axis 7 at its upstream end; therefore, at such end it is fixed, wnile at its other end, that is
the one downstream, it is capable of oscillating (see the two positions represented in 6 and 6' in figure 1). At the downstream end of the conveyor plane 6 a frame or structure 8 is arranged which carries in fixed position, one over the other and distanced in height, supports 9 and 10 on each of which a roller plane is mounted, the rollers 11 and respectively 12 of which are arranged with their axes in the longitudinal direction of the apparatus; such rollers are driven through means not shown. The members 9, 11 and respectively 10, 12 forme therefore two receiving planes, vertically fixed, and motor driven.
Downstream of said two receiving planes and in the transversal direction with respect to the apparatus, a raising plane is arranged,formed by supports 13 on which rollers 14 are mounted, motor driven through means not shown. Said raising plane is caused to move vertically between the two positions 13, 14 and respectively 13', 14', represented in figure 3, through actuating means not shown. Downstream of the raising plane slanted roller planes are finally placed, the rollers 15, 16 and 17 of which are idle mounted so as to cause the material which will be fed thereto to slide by gravity.
The operation of this first part of the apparatus according to the invention is as follows:
The cardboard sheets fed as has been already stated from the exit of the cutter to the conveyor plane 6, are fed by the latter in rapid succession to the receiving plane 9, 11 where they will be stopped against a wall 18 of alignment provided with means for its translation in the longitudinal direction of the apparatus; such wall will have been previously fixed in the appropriate position for the particular format of the incoming sheets ( plane 10, 12 also has an alignment wall 19).
When the quantity of sheets which have deposited one over the other on plane 9, 11 darkens a transversal timed photocell (not shown), automatic means (not shown) cause the conveyor plane 6 to rise, through rotation on its axis 7, by a certain tract, that is till the photocell is again in light, and so on in the sense that every time that the latter is darkened, after a prefixed time in function of the timing of the photocell,plane 6 rises. A limit switch'(not shown) arranged in a position corresponding to the height of completion of the group of sheets on plane 9, 11, as soon as the downstream end of plane 6 will be stopped against it, it should be noted that at this point the plane 6 is not yet in position 6', but in an intermediate position between 6 and 6') causes the following automatic operations through usual not shown means: the conveying movement of the sheets by the plane 6 is stopped; a gate device goes into operation; (the latter has been shown, for simplicity, only in coincidence of position 6' of the conveyor belt, but should be imagined as existing in coincidence also of position 6 and in any other position which the conveyor belt may assume, said gate device being integral with the latter); the gate device comprises a lower roller 20 and an upper roller 21, which is mounted on arms pivoted in 22; the going into operation of such gate device involves the placing into rotation of roller 20 and the lowering of roller 21; the latter acts as pressure roller while roller 20 acts as accelerator roller for the ejection of the sheets arranged in this moment between rollers 20 and 21; when this ejection is terminated, the plane 6 is replaced in conveying motion, while the gate 20, 21 in closure (roller 20 stopped) stops the incoming sheets against it; at the same time conveyor plane 6 is further raised at its downstream end so as to bring it at the operating height which is adequate for the feeding of the upper receiving plane 10, 12; as soon as it has reached such a position and with previous opening of gate 20, 21, plane 6 will immediately begin (with the same progressing raising motion already illustrated for plane 9, 11) feeding of the sheets on plane 10, 12. While formation thereby takes place of the group of sheets on the latter plane, the lower one 9, 11 unloads, through placing into operation of rollers 11, the group of sheets on the raising plane 13, 14 after automatically moving away wall 18 in order to not cause a hindrance to such unloading of sheets.
The raising plane 13, 14 as soon as it has received the group of sheets is brought to the upper level (13', 14', in figure 3); at this point its rollers are placed into action and the group of sheets will be unloaded definitely on the gravity roller planes formed by rollers 15, 16, 17. In the meantime the formation of the group of sheets will have been completed on upper receiving plane 10, 12, that is the conveying plane will have been brought into position 6' against another limit switch, whereby all the operations already illustrated with reference to the lower receiving plane will be repeated; the group of sheets will be then unloaded onto raising plane 13', 14' and then onto said gravity roller planes. The conveying plane is then immediately brought back to the position 6 and will begin to feed plane 9, 11 again; it should be noted that rollers 11 had been already stopped, that is as soon as the ejection of the group of sheets on the raising plane had been completed; the latter, with its rollers stopped, is also brought back.,to the lower level. The operating cycle just described continues therefore without interruption in a completely automatic manner. It should be noted that, as appears from the foregoing, the conveyor plane 6 stops only for an extremely short time, that is for the time,required for lowering of roller 21 and ejection of the sheets placed between the two rollers 20, 21 of the gate; such period of time is of the order of about two to three seconds. The illustrated combination of a conveyor plane vertically movable at its downstream end, with two vertically fixed receiving planes and with a raising plane vertically movable till it reaches the levels of the two receiving planes, allows to eliminate almost completely the idle times of the prior art, which resulted much more damaging to the total operating efficiency of the entire machine. By means of this invention, the upstream feeding machine may continue to operate at full speed and also at the highest productive rates. Furthermore, as has been already mentioned at the beginning, it is clear that with the system illustrated herein, it will be possible to separate with extreme ease and accuracy one order from the other, that is one format of sheets from the next format, without even wasting the time which would otherwise be required to set the new measure on the aligning wall; in fact, while the group of sheets of one format is being completed on one of the two receiving planes, the wall will be automatically brought to the position of the next format on the other receiving plane which will be therefore already preset, without any waste of time, for receiving the group of sheets of the new format. It is also clear that, due to the extremely short period of time of stopping of the unloading from the conveyor plane, the accumulation of sheets on such plane will result in being of an extremely reduced height, such therefore that it will not cause any inconveniency; moreover such accumulation takes place at the downstream end of the conveyor plane, against the gate.
It should be noted that, in order to take into account the arc of circumference on which the vertical movement of tne downstream end of the conveyor plane develops, that is in order to not create an interference between said end and the group of sheets on the receiving plane upon unloading thereof from the latter, it is possible to operate in a usual manner in two different ways, that is rendering movable back and forth (for the few required centimeters) in the longitudinal direction of the apparatus the frame 8 (through means not shown), or providing said gate device with a head part (not shown) movable in the longitudinal direction of the apparatus, having also the function of levelling the sheets of the group of sheets.
In coincidence of the upper exit 4, 5 a further conveying system is arranged, formed by a conveyor plane 23, vertically fixed, which connects with a next conveyor plane 24 pivoted at its upstream end; downstream of
the conveyor plane 24 a frame 25 is arranged carrying two receiving planes, vertically fixed, formed by supports 26, 27 and by motor driven rollers 28, 29; each of the receiving planes is provided with a wall 30 and respectively 31. Downstream of the receiving planes 26, 28 and 27, 29 a raising plane is arranged comprising supports 32 and rollers 33 (in figure 4 also the upper position 32', 33' is shown); finally, downstream with respect to the raising plane 32, 33 gravity roller planes are arranged with rollers 34, 35 and 36. In 37, 38 and 39 the members are indicated of a gate device which is the same as that in 20, 21, 22. The operation and advantages of the upper conveyor system 23, 24 and of the two receiving planes with the related raising plane placed downstream thereof, are substantially identical to those already illustrated with reference to conveyor plane 6 and related receiving planes and raising plane.
With reference now to figures 5, 6 and 7, in such form of embodiment the whole part related to the lower exit of the cutter (that is members from 6 to 22) is identical to that already represented in figures 1, 2 and 3. The upper conveyor system 23 and 24 with related gate device is also the same as that already shown for them in figures 1 and 2; the downstream part of the conveyor plane 24 is instead modified with respect to figure 1, 2 and 4.
Downstream of the conveyor plane 24 a frame 40 is arranged which carries a vertically movable receiving plane, formed by supports 41 and motor driven rollers 42. Such plane is provided with a movable wall 43 for alignment. Downstream of said receiving plane 41, 42 a roller plane 44, 45 is arranged.
According to such variation, the movements in the vertical direction are divided into two, and therefore with a saving of idle times; a part thereof is in other words carried out by said receiving plane, and another part by the conveyor plane. The beginning of the cycle takes place with the receiving plane in the position shown in a continuous line in figures5-7, that is in position of upper limit, and with the conveyor belt in the position 24, that is in the position of lower limit; when the sheets unloaded onto the receiving plane darken a photocell (not shown), the plane 41, 42 lowers, continuing gradually to receive the sheets from the conveyor plane; as soon as the receiving plane reaches the lower level 41', 42',. the conveyor plane begins to rise continuing to feed the sheets which will therefore gradually complete the stack 46. It is clear that, as soon as the conveyor plane will reach position 24' the first operations already described with reference to the limit switch of the conveyor plane 6 of figure 1 will take place in succession, that is up to the closure of the gate. Then as soon as the stack 46 has been discharged onto the roller plane 44, 45 by means of placing into rotation of rollers 42', the receiving plane and the conveyor pane will be simultaneously brought back (the first rising and the second descending) to the initial position; at this point, after opening of the gate 37, 38, 39 a new cycle of formation of the stack will immediately begin.
With reference finally to figures from 8 to 11, wherein the same reference numbers indicate members corresponding to those of the previous figures, it is clear that this variation is a reduced form of embodiment, that is less sophisticated and more economical, with respect to that of the figures from 1 to 4, in the sense that each of the two frames 8 and 25 carries only one receiving plane, vertically fixed, instead of two planes; therefore also the raising plane is missing, such as the'type 13, 14 and the 32, 33 one of figures from 2 to 4. In such a case only the time of descent and rising of't.he receiving plane is recuperated (idle time, which would be required if the receiving plane was vertically movable instead of being fixed), but the time of ejection of the group of sheets from the receiving plane is not recuperated, since, during such time, there not being present a second receiving plane, the conveyor plane cannot continue to carry out its supplying function (it is in movement but with the gate closed). However, also in this case, besides the advantage of having considerably reduced the idle times, as already previously stated tne further advantage is achieved that the
accumulation of the sheets on the conveyor plane during the time of closure of the gate device, that is during the discharging of the groups of sheets from the receiving plane, is formed not in coincidence of the upstream end of the conveyor plane but in coincidence of its downstream end, with the consequent already illustrated advantages.
It is obvious that numerous and different variations and modifications may be brought to the above illustrated forms of embodiment shown by way of example of the invention,without departing from its scope; it is intended that all such variations and modifications fall within the field of the invention itself.

Claims

1. An automatic apparatus for forming and ejecting piles of sheets at high speed, characterized by the fact that, at one or more exits of a continuous feeding machine of sheets, it comprises:

conveying means pivoted exclusively at their upstream end so as to be capable of oscillating vertically at their downstream end; one or more receiving planes vertically fixed, arranged one over the other vertically at a distance, or one receiving plane vertically movable, fed by the downstream end of said conveying means, said planes being provided with motor driven means, such as rollers, conveyor belts, or the like, said vertically fixed planes, in the case where there are two or more, being fed one after the other by said conveying means and cooperating with raising means, arranged downstream thereof, translatable vertically from one to the other of the levels thereof, and provided with motor driven means such as rollers, conveyor belts or the like, so that,once the piling of the sheets has been completed on one of said fixed planes, while it unloads the pile on said raising means said conveyingmeans feed without solution of continuity another fixed plane which then unloads the pile on the raising means, which have emptied and have been brought in the meantime to the level of this plane and so on; and photocell means or the like, which as a function of the height of the pile formed on said planes, control the raising of conveying means which cooperate with said one or more fixed receiving planes or control the lowering of said movable receiving plane and the subsequent raising of rhe related conveying means, there being provided gate means which, after having ejected the last sheets arrived thereto, temporarily close the supply of sheets from the conveying means to said planes, said gate means being arranged at the downstream end of the conveying means and being controlled by a limit switch of the latter, there also being provided usual control means for stopping the operation of the conveying means only for the extremely short time of the step of ejection carried out by said gate means and for automatically synchronizing all the various operating phases of the apparatus, particularly the ejection of sheets from the receiving planes, the re-opening of the gate means, the ejection of the sheets from the raising means and the translation of the latter up to the appropriate level.

2. The apparatus according to claim 1, characterized by the fact that said conveying means, at a first exit of said mach.ine, comprise a conveying plane operating through belt means or the like, which feeds a first fixed receiving plane and, as soon as the piling of the sheets has completed on the latter, a second fixed receiving plane, first raising means being arranged in a transversal direction with respect to the apparatus at the unloading side of said two fixed planes and unloading in turn the sheets onto further roller planes, for example of the gravity type, while said conveying means, arranged at a second exit of said machine, comprise a first conveying plane operated through belt means or the like, vertically fixed and connected with a second'.conveying plane operated through belt means or the like, pivoted at its upstream end, said first and second conveying planes being arranged above said conveying means related to said first exit of the machine and above said related fixed receiving planes, so as to pass over same, at the downstream end of said second conveying plane there being arranged two fixed receiving planes feedable in succession therefrom and unloading, in a transversal direction with respect to the apparatus, on second raising means, which unload in turn the sheets on roller planes, for example of the gravity type.

3. A device according to claim 1 or 2, characterized by the fact that on each of said receiving planes an alignment wall is arranged against which the sheets are stopped, said wall being movable along the receiving plane and being provided with means by means of which it, while on another receiving plane a group of sheets of a certain format is being formed, may be brought and fixed into the position corresponding to a new format of sheets.

4. The apparatus according to any of the preceding claims, characterized by the fact that downstream of said movable receiving plane there is arranged, at the same level of the lower limit position reachable by said movable receiving plane, a fixed roller plane for a final discharge, said conveying means, which feed the movable receiving plane, beginning to raise as soon as the movable receiving plane has reached said lower limit switch position.