APPARATUS FOR SEVERALLY REMOVING OF SHEET LIKE OBJECTS FROM A PILE

Abstract: By an apparatus or removing of sheetlike objects from a pile (5) of the kind described in Danish patent application published under the No.129.331, the displacement of the pusher means (7) and the stop means (20) respectively downward to abut against the top of the pile is accomplished by separate moving devices (10 and 23 respectively). Hereby is secured that a pusher means (7) and the stop means (20) always will function as intended notwithstanding variation in the level from the one side to the other side of the pile. In the case of thin sheet objects provisions are available by the removing to bring the top object to bulge upwards to eliminating the mutual sticcing between the sheets.

Description: Apparatus for severally removing of sheetlike objects from a pile. The present invention relates to an apparatus for several¬ ly removing of sheetlike objects in a constant level from a pile placed on a raising table and feeding same to a working machine or other destination, and where on one side of the top of the table is placed pusher means slideable in the plane of the sheets, and which on its surface turn¬ ing against the pile is provided with a step, the height of which is a little less than the thickness of the sheet to be displaced to the opposite side of the pile perpendi- cular to the direction of the feeding, and the opposite side of the pile partly stop means to abut against the top of the pile and which outside the pile is provided with a slit, the width of which corresponds to the thickness of the sheet to engage the top sheet displaced by the pusher, part- ly forwarding means arranged to engage the side of the sheet released from the pile to forward same. Preferably, but not necessarily this operation may be per¬ formed by suitable arrangement of control means in a way known per se, whereby simultaneously with the pusher means being brought to abutment with the edge of the top sheet on one side of the pile, the stop on the other side of the pile is forced downward against the pile with a force of such magnitude that the displacement force produced by the pusher means will not be able to overcome the friction generated between the sheets, until the compression force of the stop means against the pile at the moment, when the displacement has to take place, is reduced so much that the displacement force of the pusher will be able to over¬ come thie friction resulting in a momentary displacement of the top sheet into the slit intended herefore-, v/hereafter the forwarding means generally consisting of a pair of roj. lers begin to function and forwarding the sheet. By known apparatus of this kind the varying pressure of th stop means against the pile may be achieved by the table lifting the pile against the stop means with a sufficient force, which at the given moment is reduced. In the case where the sheet has to be delivered in rapid succession from a pile with a relatively great mass, the inerti of th will diminish the desired accuracy of the function of the apparatus , and it has therefore been proposed to limit the function of the table only to lift the pile successively so that the top of the pile constantly will be in the same level and produce the desired variation of the pressure o the stop means against the pile by a vertical displacement of a cross bar placed over the pile, and which is supporti the pressure means and -the stop means. Although this apparatus has been able to work satisfactori under ideal conditions, it has been experienced in practic not to be able to satisfy all the requirements which today are demanded for devices of this kind, where in view of pr fitability a great versatility is desired as to the object to be handled and a full automatic function, which implies that the apparatus can work without a steady operator and in many instances without any supervision. Relating to the sheet materials to be handled there will i iron-metalindustrial production occur plate thickness from 0.5 mm and upwards to f.inst. 15 mm, and within the tin- industry plate thickness from 0.10 mm to 0.30 mm. Especially, the apparatus according to the invention shoul with a great liability be able to handle objects, which ar not subjected to strict tolerances as f.inst. strips of sheets, where the width within the same pile may vary up to 10 mm, and where the length of the strips may vary with in broad limits as well as sheets, the thickness of which may vary from one side to the other. Even if this variati may be rather small for a single sheet, it will be under- stood that if the variation is directed to the same side of a pile of sheets by the hundred, these will mount up to a size, whereby it would be rather difficult to obtain a reliable function of the apparatus. This may also occur due to burrs which will generally appear by cutting of sheets, and in the cases where the edges of the objects have been damaged by impacts during transport. Another serious problem by the moving of sheetlike objects from a pile depends on the sheets generally being provided with a protecting layer of grease or oil, as well as sheets intended for the manufact ring of f.inst. tins before the mechanical treatment are provided with a lacquering. Re¬ garding all these coatings it must be taken into account that their thickness will not always be the same, and that they will bring the sheets in a pile to stick strongly to each other, and this stickiness may be rather heterogene- ously distributed. This may be due to heterogeneous app¬ lying of the coating or various storings of the coated sheets, the difference of the surface pressure over the height of the pile, variation in the storage time as well as difference of viscocity of the greasing material and different evaporation time of the solvent. Regarding the lacquered sheets the drying ability of the lacquer and the time of storage result in variations of force, by which the sheets are sticking to each other. It is the object of the invention to provide an apparatus of the kind referred to, which also under said difficult conditions will ensure a continuous and reliable removing of sheetlike objects fron a pile. This is according to the invention achieved by designing the apparatus as defined in the characterizing clause of claim 1. This will ensure that the pusher means and the stop pro¬ vided with the slit respectively will always function as intended irrespectively of variation in the height which for the reason mentioned above may occur from the one side to the other of the pile placed on the table and perform the necessary operations in the sequence described, also by the great speed of delivery which is today required for profitable production, and which may be as high as two to three objects per second. By the handling of thin objects it may occur that owing to more or less random distributing of the stickiness between the sheets as mentioned above, it may occur that the sheet will bulge in such a way that the pusher means only will displace the forward part of the sheet strip into the slit, so that this part of the sheet when the pushermeans is returning will slip out of the slit resul¬ ting in an interruption making a manual operation necessa To avoid this the apparatus may be provided with means as defined in claim 2 to ensure that the part of the sheet i troduced in the slit will remain in this position during the retraction of the pusher, whereas the bulge produced will propagates as a wave motion through the strip and by producing an air slot releasing this strip at its whole length from sticking to the underlying strip. The releasing of the sheet material which for the reason mentioned above is sticking to the underlying sheet, is generally not momentarily but gradually in a time interva which may vary considerably from one case to the other. By the known apparatus of this kind, where the time inter¬ vals for the different operational steps are fixed, it ma therefore in may cases not be possible to reach the capa¬ city which today is desireable. By the apparatus according to the invention it will be pos sible to make use of an electric control mechanism based upon, that the sensor provided for this purpose, when an operational step has finished, submit a signal which start the following operational step. Practice has shown that i this way a considerable increase of the capacity of the ap paratus is obtained, as it will not be dependent of a de¬ finite time control, so that even if an object should be ' BU O.» present which is unusually delayed due to a greater sticki¬ ness, the apparatus will stop only for a short time, and as soon as the delay is overcome the apparatus will automati¬ cally start again and need no action from the operator. Generally, the complete removing operation will be consi¬ derably reduced. The apparatus of the kind referred to is on the front side of the pile provided with a so-called front stop, i.e. a vertical abutment surface resting against the front side of the pile at the place where the pusher means is arranged, so that the uppermost object after being displaced sidewards by the pusher during its removing passes the front stop, which on the other hand prevents the underlying object from being removed by this motion. Preferably, according to the invention this front stop may be provided with a backwardly turned abutment as defined in claim 3. Hereby is primarily achieved that the sidewardly displaced topsheet is preven¬ ted by the retraction of the pusher possibly from slipping back, in the case that the backward part of the object sticks to the underlying object. Further, the compression of the pile produced by the abutment causes the underlying object to be further secured against being drawn forward by the topobject, as well as the separation between the top- object and the underlying object may be possible on this place to insert a so-called separating knife as will be more fully explained below. By further providing the facing backward part of the front stop with an inclined plane as defined in claim 4, which inclined plane possibly may be curved, is obtained that the top object during its moving forward is lifted partly free of the pile, whereby its ten¬ dency to stick to the next object will be diminished. By the handling of thin sheets it may appear that the dis¬ placement of the edge of the sheet by the pusher at first may force the inward part of the sheet to bulge upwards. This will in an advantageous way help the disengagement of the sheet from the underlying one, provided that this bulge will not be so big that the displacement force will not be transmitted to the other side of the sheet. In view of this may be arranged over the forward end of the pile an abutment as defined in claim 5. By a special embodiment according to the invention the raising and lowering mechanism for the pusher means and t stop provided with the slit may consist of a swivelling ar as defined in claim 6. This embodiment makes it possible, after the topmost object has been inserted in and secured by clamping of the slit device and together with the pusher and the separating kni to raise it from the pile and simultaneously to move it fo ward to ensure the disengagement from the underlying objec To ensure that the object by the action of the pusher will be disengaged in its total length and not only turned abou its central part with the risk that the object in this par will still stick to the underlying object, there may fur¬ thermore at the backward end of the pile be provided a sidestop as defined in claim 7. To further ensure the disengagement of the top object, whe this has the tendency to stick to the next object, the app ratus may be provided with a side stop as defined in claim Hereby in a simple way a further lifting of the top sheet is obtained to ensure its disengagement inspite of the ten dency of stickiness. Furthermore, to ensure the disengagement separating knives may be arranged on one or more places of the pile as defin in the claims 9 and 10. The invention will be explained more fully in the followin description of some embodiments with reference to the draw ing, wherein Fig. 1 shows schematically a top view of a removing appa¬ ratus according to the invention, Fig. 2 a side view of same, Fig. 3 a front view of same, i.e. seen from the right side in fig. 2, Fig. 4 a larger and perspective view of a special embodiment of the front stop of the apparatus, Fig. 5 a detail in front view, Fig. 6 a perspective view of the front part of the removing apparatus with an altered embodiment of the devices for moving the pusher and the slittong and Fig. 7 a perspective view of a further detail. The embodiment of the apparatus shown in fig. 1-3 comprises a supporting base 1 which at its one side has protruding sidewall 2 carrying a vertical moveable lifting table con¬ sisting of a beam 3 running along the sidewall and provided with a number of brackets 4. These brackets are easily de¬ tachable arranged on the beam 3, in order to change their mutual distance in a simple way depending on the length of the sheet pile 5, which is to be handlet by the apparatus, and so that the pile may easily be placed on the brackets by means of a forktruck. Within the sidewall 2 is placed adequate lifting means not shown in the drawing provided for automatically raising the table 3,4 ' step by step, as the objects are removed from the pile 5, and so that the top object will always remain in the same level determined by a sensor 6 submitting an electrical pulse controlling the function of the lifting mechanism. For separated delivering of the objects of the pile, f.inst. to a puncher or other working machine, there is at the front end of the pile, i.e. in the right side in fig. 1 and 2 on the one side of the pile placed a pusher 7 provided for displacing the forward end of the top sheet laterally to the position shown with dot and dash lines in fig. 1. The pusher is fastened in a horizontal guideway 8 which further contains a hydraulic or pneumatic cylinder not shown in the drawing for displacing the pusher 7, which on its underside has a plane surface to abut against the upper end of the pile, and which ends with a stop, the height of which is somewhat less the thickness of the objects to be handled. In view of handling of various thicknesses of sheet, the pusher is arranged in a way that the height of the step is adjustable, but it m.ay also be possible to use easily interchangeable pushers with different height . of the step. As it is of decisive importance for the function of the a paratus that the -pusher is in accurate contact witb the t side of the uppermost object to be displaced irrespective of less occasional variations in its level, f.inst. due t the above mentioned irregularities in the thickness of th sheets, the guideway 8 is further attached to a guide 9 which is vertically displaceable by means of a hydraulic or pneumatic cylinder 10, whereby the pusher means 7,8, when starting to operate, is forced against the top objec of the pile. The vertical guide 9 is attached to a column 11 clamped to the supporting base 1 of the apparatus in grooves 12 to be adapted to the width of the objects to be handled. On the column 11 is further placed a front stop 13, i.e. a vertical stop bar engaging the forward end of the pile at the one side of this, so that the top object when having been displaced by the pusher, may be moved forward passing the front stop which prevents that the top object during t movement possibly may draw the underlying object with it. On the other side of the front part of the pile is placed an abutment surface 20, which may be forced down to abut against the top object of the pile, and which continues in the upper boundary surface of a slit 21 , the idth of whic is adjusted to be a little greater than the thickness of t object to be handled to ensure that the objects are displa laterally only one by one for further forwarding to the wo ing machine. This is very important, as a possibly simul¬ taneous forwarding of two objects f.inst. to a punching machine may involve a great risk for damage of the punch- • ing tool. The stop provided with the slit 20,21 is mounted on a guide- way 22, wherein it may be displaced in vertical direction by means of a hydraulic or pneumatic cylinder 23. When a sensor has ascertained that the top object has been displaced totally into the slit 21, a pair of feeding rol- lers 24 placed outside the pile up to the stop slit device is urged against the free edge of the top object and by their rotation will forward the object in a direction indi¬ cated by the arrow 25 to a orking machine or a like desti¬ nation. To ensure that the object is only laterally dis- placed by its front part to assume the said forwarding di¬ rection, a fixed side stop 26 is placed at the same side of the pile at its rear end. By the apparatus according to the present invention the forwarding operation takes place in the same way as describ- ed in the Danish patent application published under No. 129331 thereby, that the step of the pusher engages the edge of the top object with a pressure necessary for its lateral displacement simultaneously with the stop 20 being forced down against the object with a force of such a magnitude, that the friction between the objects will prevent this dis¬ placement. Then the compression force is reduced with a corresponding reduction of the friction between the objects, until the pusher means momentarily displaces the top object into the slit 21, whereafter the forwarding-rollers 24 come into action to forward the object. When sensors adapted for this purpose have ascertained that the object has left the pile, the operation will be repeated. Simultaneously the control devices of the lifting table will ensure that the top of the pile continuously will be on the same level. If the objects are thin sheets which for some reasons hav the tendency to stick to each other, it may occur that th sheets are bulged . in such a way that the displacement cau by the pusher will only act at the forward part of the sh whereas the backward part will remain on its place sticki to the underlying sheet of the pile. In this case, the f ward part of the sheet may simultaneously with the return movement of the pusher slip out of the slit and return to its original position, whereby the forwarding operation w not be continued as intended. To avoid this the slit 22 may be performed as a pair ofeton arranged to clamp the sheet when the sensor has ascertained that the sheet is introduced into the slit. After a ce tain ti elag and possibly by other provisions being ex- plained in the following, the stickiness of the top sheet will cease whereafter the tongue is opened and the forwar ding operation is continued by means of the rollers ,24. n other way for solving this problem is to apply a verti displaceable front stop 30, fig- 4, which at its top end a rearwardly directed cam 31 , the underside of which form an abutment 32, which after the displacement of the top s 33 by the pusher by a downward moving of the front stop 3 is urged against the pile 5 with a force causing a certai local compression of the pile to facilitate the disengage ment between the top sheet and next sheet simultaneously with the cam 31 acting as a stop prevents the top sheet to slip back. Further to make the disengagement of the top sheet 33 mor easy the front stop 30 may on its inward side be provided with a cam 34, the top of which is formed as a possibly c veinclined surface 35, by means of which the top sheet 33 when forwarded by the rollers 24 may slide and be raised of the pile. If the objects to be removed from the pile are thin and rather wide sheets sticking strongly to each other it may UR " OΛ'. 1.1 occur that the sideward displacement caused by the pusher means 7 at the front corner of the top sheet 33, will cause an upward bulge of the front part of the sheet as shown in. fig. 5, because the other corner of the sheet is sticking so strongly to the underlying one, that it will not as in¬ tended move into the slit 21. To prevent that the upward bulge may be so great that the displacement force on the other side of the sheet is seriously reduced and possibly causes a permanent deformation of the sheet, there may in the case where this possibility exists over the forward end of the pile be arranged a stop 38 adjustable to a level adequate to the existing circumstances. By the embodiment mentioned above with reference to fig.1-3 the individual vertical displacement of the pusher means 7,8 and the stop 20 with the slit 21 respectively takes place by vertical guideways . This vertical displacement, however, may also be obtained by swivelling about a horizontal axis perpendicular to the direction of the moving, f.inst. as shown schematically in fig. 6. By this embodiment is in the front of the pile and somewhat below its top placed a tube 40 protruding from the sidewall 2 of the apparatus and carrying the stop means 20 and is continued in a tube 41 carrying the pusher means 7. The tube 41 is telescopically moveable in the tube 40 in the same way as the cutter arm on a milling machine for the adjustment of the apparatus to dif¬ ferent widthes of the piles to be handled. Furthermore the tubes 40 and 41 are independently rotable about their longi¬ tudinal axis. The pusher means 7 is together with a pneumativ or hydraulic cylinder, not shown in the drawing, for activating the pusher placed axially displaceable in a housing 42, which is placed rotably about its longitudinal axis parallel with the axis • of the tu .e 41 in a sleeve 43 which by means of a girder 44 is fastened in some distance from the tube 41. To ensure that the pusher by the rotation of the tube 41 keeps its a- butment surface parallel with the top of the pile, a chain wheel 45 is mounted on the housing 42 and with a chain 46 connected with a chain wheel 47 with the same diameter secured to a shaft 47 running through the tubes 40 and 41 telescopically displaceable, and at its other end secured- to the sidewall 2 of the apparatus, so that the chain whee 46 independent of the rotation of the tubes 40 and 41 will remain in the same position and together with the chain 46 and the chain wheel 45 will assure a parallel motion of th housing 42 during the rotation of the tube 41. The stop means 20 is secured in the same way rotably about an axis parallel with the axis of the tube 40 in a sleeve which by a girder 49 is secured to the tube 40. To the st means 20 is further secured a chain wheel 50, which over a chain 51 is connnected to a chain wheel 52 secured to the sidewall 2, so that the same parallel motion is achieved a by the pusher means. By starting the removing operation the tubes 40 and 41 are rotated by means of adequate constructed and controlled mo ing devices not shown in the drawing from the position sho in fig. 6 against the watch until the pusher means 7 and t stop means 20 are brought to contact the top object in the pile with an adequate pressure. Then the moving device o the pusher is activated so that the step of s the pusher is forced against the topmost object of the pile with a neces sary force, whereafter the pressure of the stop 20 is re- duced, until the pusher has displaced the top sheet 33 int the slit of the stop means 20. When a sensor intended fo this purpose has ascertained that the sheet is totally wit in the slit, this will by the tong" . function described ab clamp the sheet, whereafter the tubes 40 and 41 possibly b not necessarily simultaneously are rotated in the directio with the watch, whereby the forward end of the sheet 33 pa ly is raised from the pile, partly drawn forward, which mo ing pattern may substantially contribute to the demolishin of its sticking to the underlying sheet. To obtain the same function of the pushermeans 7 there is further in the housing 42 below the pusher placed a separa ■ BU _OM knife 53 in the shape of a chisel-device, which by adequate moving device may be displaced upward inclined against the pusher and below the topsheet 33, when the tube 41 has start¬ ed its swivelling motion, whereby the separating knife 53 by pressing the sheet sufficient hard against the undersur- face of the pusher will act as a pair of tongs. The said swivelling motion of the tubes 40 and 41 will gene¬ rally be continued some distance beyond the vertical posi¬ tion shown in fig. 6, until the front, edge of the sheet is engaged by adequate positioned forwarding rollers, which take over the further removing of the sheet, whereby the clamping in the slit and to the pusher simultaneously is released. A further possibility to demolish the sticking between the sheets during the removal operation is shown schematically in fig.- 7 showing, a pile as seen from-the side turning a- gainst the sidewall 2 of the apparatus. The pile is here about mid-way abutting a side stop 60 placed vertically displaceable on the side wall. By the start of the removing operation, this side stop is lowered below the topsheet 33, so that the edge of this during the lateral displacement by the pusher is moved over the side stop 60. When the sensor adapted for this purpose has registered that the sheet is moved in the slit, the upward movement of the side stop 60 is initiated, whereby the edge of the sheet 33 is lifted free of the pile. As only a smaller part of the edge of the sheet is lying over the side stop 60, it will be advantageous to avoid dam¬ aging of the sheet due to too high specific surface pressure further in connection with the side stop 60 to provide a separating knife 61, which in connection with the lifting moving of the side stop moved inclined upward and inward under the sheet 33. OMPI / Wiro For the same- reason it may also under certain conditions be advantageously to place a separating knife working in the same way beside the stop means 20,21. Firnally it may also under certain conditions be advantag ously to place a side stop 27 at the backward end of the pile on that side, where the pusher means is placed. Th side stop may appropriately be turnable about a horizonta axis, so that it may be laid down when a new pile is to b placed on the lifting table. O

Claims: PATENT CLAIMS. 1. Apparatus for severally removing of sheetlike objects in a constant level from a pile placed on a lifting table and feeding same to a working machine or other destination " , and where on one side of the top of the table is placed pusher means slideable in the plane of the objects, and which on its surface turning against the pile is provided with a step, the height of which is a little less than the thickness of the object for displacing the utmost object of the pile perpendicular to the direction of feeding and at the opposite side of the pile partly stop means to abut against the top of the pile, which outside the pile is pro¬ vided with a slit, the width of which corresponds to the thickness of object to engage the top object displaced by the pusher, partly forwarding means arranged to engage the side of the object released from the pile to forward same c h a r a c t e r i z e d in, that the pressure means (7) and with the slit (21) provided stop means (20) respec¬ tively are disposed on a lifting lowering mechanism in such a way, that the said component mutually independent may be displaced down to abut against the top of the pile. 2. Apparatus according to claim 1, c h a r a c t e r i z ¬ e d in, that the slit (21) connected with the stop (20) is provided with a tong function, and that the apparatus has control means provided for immediately after the object has been placed in the slit to activate tong function to clamp the object and thereafter cause return moving of the pusher (7), and then releasing the object from the slit during the initiating of the forwarding of the object. 3. Apparatus according to claim 1-2, c h a r a c t e ¬ r i z e d in, that the front stop placed at the front of the pile (5) before the pressure means is provided with a rearwardly directed cam (31) and devices provided for ver- tical displacement of the front stop in such a way, that such cam after lateral displacement of the top object (33) is forced downward against the free corner of the next ob ject with such a power that a local compression is obtain so that the cam (31) will prevent the laterally displaced object (33) to slip back. 4. Apparatus according to claim 3, c h a r a c t e r i e d in, that the front stop (30) on its inward side is provided with a cam (34) , the top of which is formed as a inclined surface (35), placed in the way that it will lif the top object free of the pile during its forwarding aga the working machine. 5. Apparatus according to claim 1, c h a r a c t e r i z e d in,- that in adequate and adjustable height over the pile at the front end of same is placed a stop (38) for limiting the bulge of the top object during the displace operation. 6. Apparatus according to claim 1-2, c h a r a c t e r i e d in, that the pusher means (7) and the stop (20) pro- vided with a tong function are disposed turnable and paral lel displaceable on swivelling girders (44,49), which are independent turnable about an axis placed in front of the pile, and that in connection with the pusher means is pro¬ vided a horizontally displaceable separating knife (53) which in its inserted position is urging the top object (33) against the downward surface of the pusher means (7) to clamp the object. 7. Apparatus according to claim 1, c h a r a c t e r i z e d in, that at the backward end of the pile (5) opposite the side, to which the object is displaced, is arranged a side stop (27) to abut, against the pile and provided for being turned away from this position for inserting of a new pile on the lifting table. 1T 7 λ 8. Apparatus according to claim 1-7, c h a r a c t e ¬ r i z e d in, that about mid-way at the side of the pile, to which the top object is displaced during removing, a side stop (60) abutting against the pile is pr.ovided, which is vertically displaceable and controlled in such a way, that when the top object (33) is inserted in the slit, it will be lowered to get free of the top object and then again moved upward to lift the object free of the pile. 9. Apparatus according to claim 8, c h a r a c t e - r i z e d in, that a separating knife (61) is provided near the mid-way placed movable side stop (60) and con¬ trolled in such a way that it will be temporarily moved in an inclined upward direction against the top object, after this has been displaced over the side stop and moved backward and out before removal of the next object. 10. Apparatus according to claims 1-9, c h a r a c t e ¬ r i z e d in, that on the side of the slit stop device (20,21) is placed a separating knife adapted to immediate¬ ly before the raisin g of the stop device to be moved in- clined upward against the top object and moved backward and out before removing of the next object. O PI , .,. WiPO -»

Inventors: NIELSEN A
Applicants: NIELSEN A
Application year: 1980
Main classification: B65G59
IPC codes: B65H3