SEPARATING AND LIFTING DEVIE FOR STACKED-UP FLAT ELEMENTS

Abstract: According to the invention, the device for the separation, the lifting and the removal of complete flat elements includes an open structure, suited to receive in its lower central part a storage for the metal sheets (3) and two lateral stands, each supporting at its lower end a set of rollers leaning against and guiding the metal sheet to be separated and lifted; furthermore, one of the lateral stands presents under its set of rollers (25) a template (26) which horizontally displaces the top metal sheet (7) of the pile (3). The other lateral stand also presents at its lower end the set of rollers (34) and a template (35), which receives the displaced metal sheet and lifts it from the pile (3) of metal sheets. In one form of execution of the device being the object of the invention, each stand is provided with two hydraulic or pneumatic cylinders (l5, 24; 36, 4l), one being for the vertical movement and one for the horizontal movement. Another form of execution of the device being the object of the invention foresees two lateral stands (5O, 7O) being provided with a single cylinder with a vertical stroke. The separation and the lifting of each metal sheet (7) occur at first by the lowering of the two sets of rollers (25, 34), each belonging to each of the two stands, then by the horizontal displacement toward the pile (3) of the set of rollers (25) and of the template (26), which displaces a single metal sheet (7), then by the upward movement of the template (35) which receives the displaced metal sheet and by the subsequent withdrawal of the set of rollers positioned on top of said template and finally by the upward run and withdrawal of the set of rollers (25) and of the template (26), which are still leaning against the pile of metal sheets.

Description: The invention concerns a device for the separation of flat elements, such as for instance blanked discs, to be lifted one at a time and removed for subsequent operations. Some separating devices are known, which are connected with lifting devices acting on flat elements stacked in piles on an underlying storage surface. The simplest lifting devices foresee an element of contact with the piece to be lifted, which acts with a pre-determined and adjustable force. For instance, in the case of non-stainless steel sheets the pre-determined lifting force consists of a suitably dimensioned magnet, inserted in the mechanical lifting arm. On the other hand, in the case of non-magnetic materials, such as stainless steel or brass, the drawing is done by means of a sucker acting by depression. In this case too, by varying the vacuum percentage within the sucker, the lifting force can be increased and gauged to lift pre-determined weights. It is obvious that, as soon as the adhesion conditions between one flat element and the next one in the pile to be drawn from vary, the efforts necessary to separate and lift each individual elements from the other change. This happens for instance when the oil left from preceding operations dries up and acts as an actual adhesive between one metal sheet and the next. Other variabilty elements are rust or even the blanking burrs. All these elements contribute to make extremely variable the effort necessary for the sucker or the magnet to separate and lift a single piece. Thus it happens that, since the lifting strength exerted by the sucker or the magnet must necessarily be higher than the weight of one piece, very often two pieces, rather than one, are lifted at the same time. If two pieces are lifted together and put inadvertedly under a blanking or drawing die, said die may break and even the presses carrying the die may undergo serious damage. For this reason the known technique has striven to achieve a certain degree of certainty in the lifting of each single piece by performing, for instance, an exfoliation of the pieces stacked in a pile beforehand, said pile presenting toothed bars arranged on diameters being smaller than the diameters of the pieces, so that the pieces themselves, usually in the shape of discs, separate from each other. This system yields satisfactory results for some types of metal sheets, but it finds its limit of application when the thickness of the metal sheet exceeds 6 - 7 tenths of a millimeter and its diameter is larger than 3OO - 35O mm. In fact, when these limits are exceeded, the exfoliation of the metal sheets by bending is no longer practicable because of the metal sheet resistance. Other methods of separation exist, based for instance on the vibration of the entire pile, but they also present a considerable degree of uncertainty, as well as of complexity. The main purpose of this invention is that of obtaining a separating device giving an absolute certainty of separating and therefore lifting each individual piece, regardless of the thickness of the metal sheet, of its size, of the type of material and of the conditions of preservation of the stacked up metal sheets. Another projected goal is that of obtaining that the separating system be not only reliable, but also very simple and independent from the flatness condition of the pile of metal sheets. Not the least goal is that the device be easy to use, requiring little or no maintenance and be economical. All the above mentioned goals, and others which will be better explained hereafter, are achieved with the construction of a device including a supporting frame, in which there is a structure being open at its lower central part, so as to lodge the table for the storage of the metal sheet pile, and two lateral stands, each carrying at its lower end a carrier receiving the metal sheets to be separated and guiding them. Each stand presents also a template for the separation and the lifting off of the metal sheets, characterized by the fact that the separation of each metal sheet is done by its horizontal displacement and the vertical lifting of one of its corners from the underlying metal sheet, said movements being operated horizontally by a gauged template which is fixed on the underside of the set of rollers being lodged at the lower end of one of the lateral stands, and vertically by a gauged template also being lodged at the lower end of the opposite stand forming the device. According to the invention, at the beginning of the working cycle, the two lateral stands of the device are lowered until the sets of rollers incorporated in the slides, which are supported by said stands, come to rest against the top metal sheet of the pile, which is the sheet to be separeted and lifted off. At this point, the set of rollers supporting the separating template moves horizontally and pushes laterally by means of the template a single metal sheet, since the template is fixed in a position, which is lower in relation to the set of rollers, by a distance corresponding to the thickness of the sheet to be separated. In the other stand , on the other hand, the template which operates the lifting off of the metal sheet segment, is always positioned at a higher level than the sheet to be lifted, although this distance is only slightly larger than the thickness of the metal sheet, so that the segment of sheet which has been moved horizontally, comes into contact, with its upper surface, with the lifting template. The next movement of the device is that of moving upwards the template, which has lifted the corner of the metal sheet, while the set of rollers of the other stand continues to rest against the laterally displaced metal sheet. Thus, the metal sheet separates completely from the underlying metal sheet belonging to the pile. At this point, an arm carrying a magnet or a sucker can lift the entirely separated metal sheet. The cycle is concluded when the templates, together with the sets of rollers, return to their initial position. One of the advantages of the device is represented by the fact that it does not take into account the flatness of the metal sheets to be separated from the pile. In fact, the sets of rollers incorporated in the stands of the device always go to rest against each individual sheet to be separated and lifted, and this occurs even if the metal sheet is not perfectly flat. Another advantage consists in the fact that, since the gauging of the thickness is in relation with a fixed mechanical master gauge, the device does not need to be equipped with closeness sensors or with delicate devices, which would increase the need for maintenance. Other characteristics and advantages of the invention will be better understood from the description of two preferred forms of execution of the invention, given by way of examples only, but which are not meant to limit the scope of the invention itself, such as it is described and illustrated in the enclosed tables of drawing, wherein: - Fig. l represents the separating and lifting device fed from a storage shelf; - Fig. 2 is a cross section of the device according to the invention; - Figs. 3, 4, 5 and 6 show the sequence of the various operation stages of the device according to the invention. - Figs. 7 and 8 show two successive operation stages concerning a different form of construction of the stand carrying the separating template and of the stand carrying the lifting template With reference to the mentioned figures, the device according to the invention is mounted on a metal structure, consisting essentially of a supporting base l and of a stand 2. Said metal structure is suited to receive the pile of metal sheets 3, which is lifted by a platform being mounted at the end of a shelf 5 which moves vertically under the driving force of the rotating screw 6 being guided by stand 2. A driving device of a known type - which therefore is not described in detail - causes pile 3 to move gradually upwards as the metal sheets are separated and removed by the automatic transferring arm. The separating and lifting device, indicated as a whole with lO, is supported by a structure consisting of steel plates connected with stand 2. Two tube-shaped elements l2 and l3 are fastened on the upper horizontal steel plate. Element l2 is fixed to steel plate ll with bolts by means of a flange l4. The upper end of the tube-shaped element l2 presents a pneumatic cylinder l5 having its stem l6, which in turn is connected with yet another cylinder l7, which can slide within the tube-shaped element l2. The lower edge of cylinder l7 is bolted by means of a series of bolts l8 to a horizontal plate l9, which presents a couple of dovetail grooves 2O. Slide 2l moves within these grooves. Said slide 2l presents two plates 22 and 23, which are welded to it and arranged vertically. The pneumatic cylinder 24 is blocked against plate 22, while plate 23 acts as a support for set of rollers 25 and for the gauged template 26. The adjustment of the maximum vertical stroke of stem l6 and, as a consequence, of cylinder l7 is carried out with the help of the excentric washer 27 which slides within slot 28, while, in actuality, the stroke of cylinder l7 is limited by the fact that set of rollers 25 rests against the metal sheet pile 3. The horizontal stroke of slide 2l is driven by the pneumatic cylinder 24, whose stem 29 is blocked at its end against the vertical plate 3O, which is rigidly connected with the horizontal plate l9.Template 26 is fixed by means of screws to the horizontal edge 3l of plate 23, while set of rollers 25 can undergo a vertical adjustment by adjusting screw 33. The difference between the lowest point of template 26 and the lowest point of set of rollers 25 is kept slightly smaller than the thickness of the metal sheet to be lifted, in order for template 26 to push laterally only one sheet at the time, as will be seen further on. What has been described concerning set of rollers 25 and template 26 applies also to the movemnt of set of rollers 34 and lifting template 35. In fact, the pneumatic cylinder 36 moves, with its stem 37, cylinder 38 which slides within the tube-shaped element l3. The horizontal plate 39 is rigidly connected with cylinder 38 and it also supports slide 4O which is made to move horizontally by the pnuematic cylinder 4l. In this case, too, the relative position between of set of rollers 34 and the template 35 is adjusted by means of screw 42. The difference between the lowest point of template 35 and the lowest point of the set of rollers 34, in this case, is sligthly bigger than the thickness of the metal sheet to be lifted; in fact, as will be pointed out further on, the separated metal sheet can rest on top of template 35 without being hindered by any obstacle. The coordinated movements of the device according to the invention which allow the separation and the lifting of the metal sheets are as follows. As can be observed in Fig. 3, the set of rollers 25 and 34, which are driven by the cylinders l5 and 36 respectively, are vertically lowered until they come to rest against the pile 3 of metal sheets to be separated and removed. During this stage, set of rollers 25 rests only with its roller 43 against pile 3, while roller 44 keeps clear of the pile. The pressure exerted by the two sets of rollers by means of the rollers 43 and 45 is adjustable and it obviously depends on the pushing force of the pneumatic cylinders l5 and 36. The purpose of this pressure is that of flattening as much as possible the metal sheet to be removed. Afterwards the pneumatic cylinder 24, which causes plate 23 to move toward pile 3, is activated. As a consequence, template 26 goes to lean against the thickness of the metal sheet 7 of the pile, which is the metal sheet to be separated and lifted off, and it causes this metal sheet 7 to be displaced on its horizontal plane, so that a portion of the metal sheet itself comes to rest on the lateral template 35 an be observed in Fig. 4. At this point it is necessary to point out that the separation which has just taken place can only concern a single metal sheet. In fact, the actual controls of the thickness are two: the first one concerns template 26 being positioned, in relation to the plane of rollers 43 and 44 of set of rollers 25, at a distance which is smaller than the thickness of the metal sheet, so that only one sheet can be pushed toward set of rollers 34; the second control concerns the position of template 35, which is lower, in relation to the lowest point of roller 45 of set of rollers 34, by a distance which slightly exceeds the thickness of the metal sheet but is always smaller than the compounded thickness of two metal sheets. After the metal sheet 7 has been displaced laterally by template 26 and pushed on top of template 35, set of rollers 34 driven by cylinder 4l draws back and, at the same time, template 35, pulled by cylinder 36, moves upward. Thus, the separated metal sheet 7, which is still pressed on one side by set of rollers 25, bends, thereby causing this metal sheet to detach itself from the undelying one, should they be stuck together, although the first one is still held in its position, so as to make easier the lifting off carried out by sucker 8, in the case of the example, or by a magnet, in other cases. The lifting of metal sheet 7 and, therefore, the upward movement of template 35 is adjustable by adjusting the stroke of stem 37 of cylinder 36. Said adjustment is necessary since it is important to lift the metal sheet 7 by a distance sufficient to detach the separated metal sheet from the undelying metal sheet. When sucker 8 has securely gripped the metal sheet, set of rollers 25 draws back with a horizontal movement, and it exits from the surface of pile 3. At the same time it moves upward, so as to completely free the area for the lifting off of the metal sheet 7, which can thus be definitely removed by sucker 8. According to a different form of execution of the separating and lifting device being the object of the present invention, the vertical and horizontal movements of the sets of rollers and of the templates are obtained in a simplified form, in that the use of a single hydraulic or pneumatic cylinder is foreseen for each group of set of rollers/template. Said single cylinder produces both the necessary movements - the vertical and the horizontal one - with the help of a suitable mechanical unit. In fact, with reference to the Figs. 7 and 8, it can be observed that the unit on the left side, indicated as a whole with 5O, presents in its upper part a single pneumatic or hydraulic cylinder 5l, whose stem, adequately guided, is rigidly connected with the lower part 52 of the stand. This lower part 52 presents at its bottom an inclined surface 53. Perpendicularly to this surface there is a pivot 54 which is free to slide within its seat and is kept protruding downwards by a spring 55 whose seat is within a cavity which is coaxial with pivot. Spring 55 is guided by a cylindrical stick 56 which is fastened to a little block 52, which in turn is rigidly connected to post 52. The sliding movement of pivot 54 is limited by slot 58, into which a pin 59 is inserted. Said pin prevents the rotation of pivot 54 and its sliding out of its seat, obtained within stand 52. The lower end of pivot 54 is inserted into yet another stand 6O and is blocked within it by means of a headless screw 6l. Stand 6O carries at its lower end set of rollers 25 and template 26, the mechanical devices which have already been described in the preceding example. When the piston of 5l is activated, stand 52 is lowered and stand 6O lowers itself with it, so that set of rollers 25 comes to lean against the metal sheet 7 which is to be separated and lifted. Since the piston of cylinder 5l continues to move downwards, so does stand 52. It thus happens that stand 6O, which is already leaning with set of rollers 25 on the metal sheet 7, moves horizontally, since pivot 54 is forced to re-enter within its seat because of the downward movement of stand 52. Thus the horizontal displacement of metal sheet 7, pushed by template 26 is obtained, as can be observed in Fig. 8. It must be pointed out that the just described form of execution, not only leads to a simplification of construction and to the use of a reduced number of components and of control organs, thanks to the elimination of the horizontal cylinder 24, represented in the example of Fig. 2, but it also makes it possible to obtain a sure synchronization of the movements, which is sure since it is determined by mechanical gauges, rather than by the coordination of electrical, pneumatic or hydraulic controls. In fact, in the execution form represented in Fig. 2, a programmed sequence of controls for the vertical cylinder l5 and the horizontal cylinder 24 is necessary, which is absolutely not necessary for the execution form represented in the Figs. 7 and 8. As far as the unit set of rollers/lifting template, which is indicated as a whole with 7O, is concerned, it is necessary to point out that set of rollers 34 needs to rest against the metal sheet 7 to be lifted and that it is important that it keeps on resting against said metal sheet during the separation procedure operated by template 26. After the separation of the metal sheet has taken place, for the subsequent lifting, which is done by the template 35, it is necessary for the set of rollers to draw back and stay outside of the vertical line passing through the edge of metal sheet 7, so as to allow the removal of the separated metal sheet by means of sucker 8, or equivalent devices. In the example illustrated in the Figs. 7 and 8 it can be observed that the horizontal translation operated by set of rollers 35, which in the example of Fig. 2 is operated by cylinder 4l, is changed into a rotation, which obtains the same operational result, which in actuality is that of positioning the set of rollers outside of the range of movement of the separated metal sheet 7. Said rotation is achieved by positioning near cylinder 7l a fixed cam 72, which is suitably shaped in its part 73.The set of rollers 34 is hinged in 75 and is constantly under the stress of spring 76, so that the set of rollers positions itself as shown if Fig. 7, when the piston of cylinder 7l is pulled upwards. On the other hand, when the operation of separating the metal sheet 7 is under way, as can be observed in Fig. 8, the downward pushing force of the piston of cylinder 7l brings, first of all, template 35, being rigidly connected with stand 77, to a position suited to receive the metal sheet 7, so that the set of rollers 34 straightens up in a vertical position and goes to lean against the metal sheet 7, since edge 78 of cam 72 forces the set of rollers to take said vertical position. In this case, too, as has been seen, how cylinder 4l can be done away with, and this brings about a further simplification of the lifting unit with the ensuing savings in the construction process and also an absolute precision in the synchronization of the movements. As has been seen, the device according to the invention has reached all the proposed goals. In fact, it has been seen that the prospected device guarantees the removal of a single metals sheet, since the separating device is based on an separating template with a fixed gauge in relation to the thickness of the metals sheet. It has also been observed that said mechanical device does not require special closeness sensors or other delicate and costly mechanisms. Obviously, during the manufacturing process, construction variations can be introduced in the just described device: said variations will not exceed the scope of the patent rights, such as they are described and defined in the following claims.

Claims: l) A device for the separation and the removal of flat elements stacked up in a pile, particularly for metal sheets, including a supporting frame having a structure being open and suited to receive in its lower central part a storage of metal sheets (3) and two lateral stands, each lodging at its lower end a set of rollers, meant to lean on and guide the metal sheet to be separated and lifted, and a template for the separation of the metal sheet and for the lifting of a segment of the metal sheet respectively, characterized by the fact that the separation of each metal sheet occurs first by its horizontal displacement and then by vertical lifting and removal, said horizontal displacement being operated by a template (26) being connected to one of the stands of the device and fixed underneath a set of rollers (25), and the lifting being operated by a template (35), also being fixed underneath a set of rollers (34) being positioned at the lower end of the other stand, further characterized by the fact that the metal sheet (7) being separated and lifted from the pile is removed by a sucker (8) or by magnetical removing means or other equivalent means. 2) A device according to claim l), characterized by the fact that the operations of separating and lifting the metal sheet occur in a sequence, first by the lowering of the two sets of rollers (25, 34) each belonging to each of the two stands and leaning on the pile of metal sheets to be selected and removed, then by the horizontal displacement of the set of rollers (25) and of the template (26) toward the pile of metal sheets, said template (26) displacing a single metal sheet (7), then by the upward movement of the template (35) receiving the single metal sheet which has been displaced, then by the subsequent withdrawal of the set of rollers(34) positioned on top of the lifting device and finally by the lifting and withdrawal of the set of rollers (25) and of the template (26), which are still resting on the pile. 3) A device according to claim 2), characterized by the fact that the template (26), which horizontally pushes the metal sheet (7) to be separated, is lower in relation to the horizontal plane where the rollers (43, 44) of the set of rollers (25) rest, by a distance which does not exceed the thickness of the metal sheet, further characterized by the fact that the template (35) which operates the lifting of the metal sheet to be separated and removed, is lower in relation to the plane where roller (45) of the set of rollers (34) rests, by a distance which slightly exceeds the thickness of the metal plate. 4) A device according to any one of the preceding claims, characterized by the fact that the movements of the sets of rollers (25, 34), of the templates, which separate and lift the metal sheets, are obtained for each set of rollers and for the templates by means of a hydraulic or pneumatic vertical cylinder (l5, 36) and by means of yet another hydraulic or pneumatic horizontal cylinder (24, 4l). 5) A device according to claim 4), characterized by the fact that the adjustment of the distance between the sets of rollers (25, 34) and their respective template is obtained by turning a screw (33, 42), which vertically moves the set of rollers (25, 34). 6) A device according to one of the claims from l) to 3), characterized by the fact that the set of rollers/template unit (25, 26), separating the metal sheets, is driven by a single hydraulic or pneumatic cylinder (5l), which vertically moves a stand (52) ending at its bottom with an inclined surface (53) being connected by means of a sliding pivot (54) to another stand (6O) also ending at the top with an inclined surface, being parallel to the first one (53), said lower stand (6O) being provided with a set of rollers (25) and a template (26) which move horizontally when the upper stand (52) moves vertically because of the action of the single cylinder (5l) being connected with it. 7) A device according to claim 6), characterized by the fact that the set of rollers/template unit (34, 35) lifting the separated metal sheet, is driven by a single hydraulic or pneumatic cylinder (7l), which vertically moves the stand (77) supporting the lifting template (35) and the set of rollers (34) placed on top of it, said set of rollers (34) having the possibility to rotate around a hinge (75) arranged horizontally on the stand (77), said set of rollers being constantly under the pushing stress of a spring (76), which positions it at an angle in relation to the vertical line, further characterized by the fact that the set of rollers, during the vertical displacement of the cylinder (7l), follows the profile of a fixed cam (72), so as to be on top of the metal sheet to be separated (7), while it is being separated, and so as to be clear of its area of movement when it is being removed.

Inventors: CARBONIERO, FLAVIO, PONTINI, ALDO
Applicants: OMERA SPA
Application year: 1987
Main classification: B65G59
IPC codes: B65H3, B65G59, B21D43, B65G69