DEVICE FOR HANDLING AND GUIDING BUNDLES WITH VERTICAL SHEET STACKERS

Abstract: A device for handling and guiding bundles with vertical sheet stackers, comprising a positioning arm (15) for the bundles (9) connected up to elements with reciprocating drive action (16-19) forming a structural assembly (21), supported on a plate (21a) affixed to the free end of a piston rod (22) of a cylinder/piston unit (23) supported in a frame (25) supported in turn in a framework (26) affixed to a trolley (13) moving forwards and backwards between the stacking station (10) and the adjoining binding station (11). The framework (16) comprises guide rods (27) and a threaded rod (28) actuated by a reversible geared motor (31). Tubular guides (25a) sliding on the guide rods (27) are provided in the frame (25), together with a nut screw (29) screwed onto the threaded rod (28). A cylinder/piston unit (36) is further provided as part of the structural assembly (21), supporting a catch pro­ jection (34) designed to prevent the sheets at the top of the bundle (9) from becoming displaced and ending up in the binding station (11) when the positioning arm (15) is retracted.

Description: The present invention concerns a device for handling and guiding bundles with vertical sheet stackers. With known vertical sheet stackers, the sheets arrive at the stacker from the rotary press in the form of a continuous overlapping stream, like scales, and are then gathered up by the stacker to form a bundle of a determined height, the sheets being superposed one on top of the other. It is a common feature of known types of stacker that for the initial stage of bundle formation a so-called vane separator is used, retractable and capable of oscillating, which is designed to be positioned in the incoming stream of sheets; this vane then transfers the sheets starting to be formed into a bundle onto a fork support that can be shifted downwards, and the formation of the bundle is completed on this fork. As soon as the bundle is completed, the fork is rapidly lowered onto an L-shaped roller conveyor underneath, linking the bundling station with the associated binding station, from where the secured bundles are then conveyed to a palletizer. It is well-known that with vertical stackers the rapid lowering of the finished bundle onto the roller conveyor underneatn is a very delicate handling operation, as the sheets are loosely aranged on top of one another, and the degree of compactness in the bundle becomes increasingly less from the bottom of the pile upwards, since its compactness is determined solely by the weight of the superposed sheets. As as result, during this rapid descent stage the bundle expands, with the well-known concertina effect, especially in the top part. This expansion makes the bundle arch out towards the outside of the stacker. The extent of this expansion, or bending outwards, varies in accordance with a variety of factors, including the type of paper used for the sheets, the number of folds provided for in the sheets, and so on. Such expansion is, for example, fairly significant in the case of sheets that are folded into three, since they will then have one side that is thicker than the rest of the sheet. Moreover, a certain amount of air will remain trapped between individual pages with these sheets. These conditions therefore heighten the "suction" effect to which the bundle is subjected at the top in its rapid descent, which provokes undulation between individual sheets so that they are liable to slide about on top of one another. As a consequence, the arrangement of the sheets in the top part of the bundle begins to break up, leading to the arching outwards that has been mentioned. Disarrangements of this kind create various problems when it comes to subsequent handling of the bundles. In the first place there are problems regarding conveyance of the finished bundles from the stacking station to the adjoining binding station, since further disarrangements may occur in the course of such conveyance, and the sheets at the top may come away from the bundle altogether. There are other problems at the binding stage. The sheets, or wads of sheets, at the top of the bundle are out of true with one another, that is to say, they project beyond the ideal contour of the bundle, and the sheets that project in this way become damaged by the securing straps and their subsequent handling while being palletized. The Italian patent no. 1163186 proposes equipping the vertical stacker with a trolley with oscillating sides in order to ensure that the sides of the bundle stay in the correct position during conveyance from the stacking to the binding station. Such trolleys, therefore, act only on the sides of the bundles, and are not capable of overcoming the difficulties referred to above. In US-4577853 is disclosed a stacking apparatus provided with follower means D comprising an arm which engages the top end of a signature stack and follows same in engagement therewith during the lowering movement of the stack to its transfer position on transfer forks 22. The arm is connected to driving elements in form of tension springs for tilting it at right angle to the bundle. The arm and the driving elements form a structural assembly hingingly linked to reciprocating elements in form of a lug, a piston and a cylinder, for moving the positioning arm up and down. The cylinder unit is anchored on a guide rod parallel to the guide surface for the stack. The guide rod is mounted inside the stacker frame, that is behind the guide surface for the stack. After depositing the stack at its transfer position on transfer forks the stack is removed by a not shown transfer device. In the disclosed stacking apparatus the follower means D can only move vertically along the guide rod 32 with the disclosed arrangement the positioning arm during its lifting movement can push the sheets forwards and therefore disarrange said sheets, particularly in the stacker top. The guiding device disclosed in US-4577853 is not able to precompress the bundle after a completition of said bundle and before the fork begins its rapid descend. The disclosed device is also not capable to transfer the bundle from the stacking station to the binding station. A precompressure of the formed stacks is not even necessary in a stacking apparatus according to US-4577853 as the disclosed stacking apparatus forms low stacks which have a small height of for example 200 mm and are not subjected to the concertina effect. Further, in United States patent no. 4.554.867 provision is made for mounting on the sides of a so-called trolley longitudinal cylinder/piston units on the free upper end of whose piston rods is attached a transverse cylinder/piston unit. After the bundle has been completed and lowered in a rapid descent onto the roller conveyor, and the sides of the trolley have been closed in a rotary movement against the bundle, the piston rods of the transverse cylinder/piston units are expelled so that they are positioned above the bundle. Next the piston rods of the longitudinal cyclinder/piston units are retracted, causing initial compression of the bundle before it is conveyed to the binding station. Clearly, this pressure on the bundle is effected after the disarrangements of the sheets referred to above will have taken place, so that neither is this action by the trolley capable of overcoming the difficulties already mentioned. The object behind the present invention is the creation of a device for handling and guiding bundles with vertical sheet stackers that can overcome the difficulties referred to above and can provide a reliable means of preventing undesirable arching of the top part of the bundles in the course of their rapid descent, and disarrangement of the top part of the bundle during its conveyance from the stacking station to the binding station, and more precisely until the inception of compression proper in the course of the binding process. It is within the range of the stated object to provide for a compact device, of simple design, that can be used, moreover, with existing stackers. In stackers already equipped with a trolley for guiding the bundle, the device to be proposed must also be capable of being mounted advantageously on the trolley. The object behind the present invention is achieved by the concept it contains of a device for handling and guiding bundles the special features of which are to be found in the characterizing part of claim 1. Further structural characteristics of the device that is proposed are to be found in the characterizing parts of the claims following the principal claim. Numerous advantages are obtained with the device for handling and guiding bundles according to the invention. Above all, with the bundles being prevented from becoming disarranged, the whole of the process of handling the sheets can now be automated, from their arrival at the stacker till their delivery to the palletizer, in secured bundles. Preventing the bundles from becoming disarranged prevents the occurrence of damage to the sheets, and rejects, and hence also problems for the downstream machinery dealing with the sheets, the pick-up machines, for example. This further alleviates the supervisory task of the operator, whatever the type of sheets being handled. The proposed device also operates advantageously in such a way as not to interfere with the speed of stacking, even at the highest speeds. The proposed device is of compact design, and can accordingly be used without any problem with existing stackers. If these are equipped with a trolley for conveying the bundles, the proposed device can be advantageously mounted on the said trolley. Another advantage of the device according to the invention is to be seen in the fact that it is capable of handling bundles made up from any types of sheet, or sheets made of any kind of paper, without any prior adjustments being required. Further characteristics, advantages and details of the handling and guiding device according to the invention will become clear from the description that follows, with reference to the attached drawings, illustrating by way of example a preferred embodiment of the proposed device, which is shown as one possible example, and is not limitative. The drawings illustrate: Fig. 1: frontal diagrammatic view of a vertical stacker equipped with the device for handling and guiding bundles according to the invention, with adjoining binding station for the bundles; Fig. 2 side elevation view of the stacker in Fig. 1; Fig. 3 larger scale side elevation illustrating the device for handling and guiding bundles according to the invention; Fig. 4 frontal view of upper part of the device according to the invention, seen in the direction of arrow A in Fig 2; and Fig. 5 - 9 diagrammatic side views illustrating the different stages of bundle-handling according to the invention. In these above-mentioned figures, for which differing scales have been used for greater clarity, and in which identical parts are denoted by the same reference numerals, 1 denotes a vertical stacker of the type that is known, as can be found, for example, in the application for Italian patent no. 1163186 filed by the Applicant. This exhibits a feed channel 2 for the sheets 3 as well as a vane separator 4 for starting the formation of the bundle and a fork 5 for completing the bundle and for lowering it in rapid descent onto the roller conveyor 6, comprising a number of rollers forming a backpiece part 7 and a bed part 8. The completed bundle is denoted by 9. This is made up at the stacking station, denoted by 10, whilst 11 denotes the adjoining station where the bundle is secured, which is per se known. In the version illustrated, 12 denotes guide bars on which a mobile trolley 13 is provided for conveyance of the bundle, as specified in the application for Italian patent no. 1163187 filed by the Applicant. For the sake of simplicity, in the version shown the trolley 13 is used that is already envisaged as support for the handling and guiding device according to the invention, depicted as an ensemble at 14. Again for reasons of simplicity, the mechanism for transporting the trolley 13 is not illustrated, since this, together with the oscillating side arms 13a, can be selected at discretion. The device 14 according to the invention comprises a reciprocating action positioning arm 15, at right angles to the roller backpiece 7, or to the bundle 9, such action being imparted by a rotary cylinder/piston unit 16, known per se, to whose output shaft there is splined a circular serrated sector 18. The latter engaged with a rack 19 fixed by means of screws (in a method not illustrated in detail) to the positioning arm 15. The numeral 20 denotes the ensemble of a slide guide element to which the arm 15 is attached to ensure that the same moves in the correct reciprocating linear motion. The arm 15 and the rotary cylinder/piston unit 16 and the other above-mentioned components form a structural assembly 21 mounted on a support plate 21a. The latter is attached to the end of a piston rod 22 of a cylinder/piston unit 23, whose cylinder 24 is affixed to a movable frame 25, referred to below, on a framework 26 affixed to the trolley 13. The numeral 25a denotes guide rods parallel with the piston rod 22. The frame 25 is guided on the framework 26 by means of tubular guides 25b sliding over two guide rods 27 of said framework 26, and can be moved forwards and backwards within it with the aid of a threaded rod 28, supported in the framework 26 in such a way that it can revolve but cannot be axially shifted, and a nut screw 29 supported in a fixed position on the bottom crosspiece 30 of the framework 26, or on the trolley 13. The way the device according to the invention described here operates is now set out with reference to the different operational stages illustrated in Figs. 5 - 9. After the formation of the bundle 9 has been completed on the fork 5, the positioning arm 15 is brought out (Fig. 5) and immediately before the fork begins its rapid descent the bundle is precompressed, in accordance with the invention, the arm 5 being caused to execute a rapid descent by the action of the cylinder/piston unit 23 (travel h in Fig. 3), so as to ensure that the well-known expansion of the bundle does not occur and to cause it, preferably, to be lightly precompressed (Fig. 6). The bundle, lightly precompressed in this fashion, can now be lowered in rapid motion onto the fork 5 without any problem. At the inception of this motion of the rapid lowering of the bundle 9, the motor 31 starts to rotate the threaded rod 28 and at the same time causes the frame 25 to be lowered, or the arm 15, and, to be precise, in synchronisation with the speed of the rapid descent of the bundle, or the fork 5. When the bundle 9 reaches the roller bed 8 of the roller conveyor 6 (Fig. 7), the fork 5, or the bundle 9, halts its descent, and at the same time the downwards movement of the frame 25 also comes to a halt. There now takes place the stage of conveyance of the bundle 9 from the stacking station 10 to the binding station 11 through movement of the trolley 13, by a method that is per se khown. It is to be noted that while the bundle is being conveyed is this way the positioning arm 15 keeps the bundle 9 slightly precompressed, or correctly positioned. When the bundle 9 arrives at the binding station 11, the compression pistons 32 then descend, in the known way; they are equipped with an end board 33 supported by the same by means of suckers, for example, not further illustrated. The pistons 32 terminate their stroke shortly before coming into contact with the positioning arm 15 (Fig. 8). Next the arm 15 is retracted, via the unit 16, and the compression pistons 32 carry out the compression proper of the bundle 9, which is followed by traditional strap-binding. Since at this operating stage, the retraction of the arm 15, some of the sheets at the top could still become displaced, as they tend to follow the arm 15 as it moves, according to the invention the use of a positioning catch protection is provided for, as shown in Figs. 2, 3, 5 and 9. In practice this projection takes the form of a small plate 34 attached to the free end of the piston rod 35 of a cylinder/piston unit 36, likewise supported in the structural assembly 21 already mentioned. Before the arm 15 is retracted from the bundle, the unit 36 is actuated, causing the piston rod 35 to be ejected and the catch protection 34 to be positioned in front of the bundle 9 (Fig. 9). In this way the sheets at the top are reliably prevented from following the arm 15 in its retraction movement. After the pistons 32 have commenced their compression operation, the catch projection is retracted once more. The trolley 13 thereupon executes its return run and the device 14 therefore returns to the stacker 10. In the meantime the motor 31 has rotated, in the reverse direction, the threaded rod 28 and the frame 25 returns to its up position. The cylinder/piston unit 23 will meanwhile have caused the structural assembly 21 to rise, so that the positioning arm 15 is now ready to be brought out again on the next completed bundle 9. From the description of the construction and function of the device according to the invention it can be seen that it provides an effective solution in terms of the underlying object of the latter, and enables the advantages mentioned in the introductory section to be put into practice. In practice, all the separate parts, or the separate components, can be replaced by others that are equivalent from a technical and/or functional point of view, but this is no ground for discarding the range of protection in respect of the present invention. For example the cylinder/piston units that are described could be replaced by units comprising a rack and motor-driven pinion, or different configurations could be selected for the support frame for the positioning arm, as also of the framework housing the frame, and so on, without any abandonment of the range of protection of the invention. It is likewise within the range of the present invention to provide for a vertical positioning arm in the shape of a beak, hinged onto the said frame so that it can oscillate and move forwards and backwards towards and away from the bundle 9. All the characteristics to be found in the description, claims and drawings are considered to be essential for the present invention, both singly and in any combination of them.

Claims: Device for handling and guiding bundles with a vertical sheet stacker comprising a rolley conveyor (6) for conveyance of the bundles (9) from a stacking station (10) to a binding station (11) and including an arm (15) for positioning the respective completed bundles (9), the arm being connected to driving elements (16 - 19) for moving it at right angles to the bundle (9) and forming therewith a structural assembly (21) linked to reciprocating elements (27,23) for moving it (15) up and down, and the driving elements (16-19) connected to the arm (15) being able to move it backwards and forwards, characterized in that the reciprocating elements (27,23) are able to move the structural assembly (21) up and down at rapid speed, this reciprocating elements (27,23) being supported, with guide rods (25a), on a frame (25) housed in such a manner that it can move reciprocatingly in a plane parallel to the plane of the bundle (9), the frame (25) being housed in a framework (26) supported in its turn on a trolley (13) that can be moved in parallel with the rolley conveyor (6), and in that catch devices (34) operating in conjunction with the top part of the bundle (9) in the binding station (11) are also provided. Handling and guiding device in accordance with claim 1, characterized in that the driving elements (16 - 19) connected to the arm (15) comprise a rotary cylinder/piston unit (16) attached to the arm (15) through the interposition of a rack (19) affixed to said arm (15) and engaging in a serrated sector (18) splined to the output shaft (17) of said cylinder/piston unit (16), and in that t positioning arm (15) is linked with a rectilinear ball slide guide (20) housed in that structural assembly (21) which is supported on the rod (22) of a cylinder/piston unit (23) the cylinder of which is of one piece with the said movable frame (25) in the framework (26) affixed to the said trolley (13) that moves backwards and forwards between the stacking station (10) and the binding station (11). Handling and guiding device in accordance with claim 1, wherein the said framework (26) comprises two guide rods (27) and a threaded rod (28) in the middle supported in such a manner that it can revolve, but cannot be axially shifted, by a crosspiece (30) of the said framework (26) and connected to a reversible geared motor (31). Handling and guiding device in accordance with any one of the preceding claims, wherein the said frame (25) comprises an upper crosspiece and a lower crosspiece exhibiting tubular guide elements (25b) that slide on the said guide rods (27) of the framework (26) affixed to the trolley (13), there being housed in the lower crosspiece of said frame ( 5) a nut screw (29) screwed onto said threaded rod (28) supported by the framework (26) to ensure that the downward and upward movements of said frame (25) and, indirectly, of said positioning arm (15) are synchronised with the speed of movement of the fork (5) supporting the bundle (9). Handling and guiding device in accordance with any one of the preceding claims, characterized in that the structural assembly (21), the frame (25) and the framework (26) are mounted on a trolley of their own that can move backwards and forwards between the stacking station (10) and the binding station (11). Handling and guiding device in accordance with any one of the preceding claims, characterized in that the structural assembly (21), the frame (25) and the framework (26) are mounted on the trolley (13) for conveying the bundle (9) between the stacking station (10) and the binding station (11) belonging to the stacker.

Inventors: CASTIGLIONI, ANTONIO
Applicants: CIVIEMME S.R.L.
Application year: 1988
Main classification: B65H31
IPC codes: B65H31