DE4203500A1 - Sheet feeder with stacking table and sheet separator - has time staggered outward movement of secondary stacking table spikes beneath remaining stack - Google Patents

Abstract

The first part of moving out the spikes takes place at increased speed and the last part takes place at lower speed. Through the staggered movement the remaining sheet stack (5) passes into the areas of the different spikes at different times so that the sheets slide smoothly from the spikes (15) onto the sheet stack (3). ADVANTAGE - Accurate alignment of the sheets. By avoiding sudden loads the sheet feeder can be made lighter with reduced structural size.

Description

The invention relates to an arch feeder with a stacking table for holding a sheet stack, with a sheet separator direction, which is arranged above the stacking table is net and by which the top one Sheet of the sheet stack detectable and one further processing machine can be fed, the stacking table being the top one Arch at a certain level hal tend to be vertically movable, with an auxiliary stacking table that several in the Ab stood side by side in a hori has skewers arranged at the central level, which by a drive device among the remaining from the stacking table Sheet stack are movable, the auxiliary stacked the load of the sheet stack over taking and its top bow on the certain vertical level is drivable while the stack table to hold a new stack of sheets can be lowered and lowered to its lowest position closing up to the top arch  of the new sheet stack on the lowest sheet the remaining stack of sheets can be lifted, as well as the skewers of the auxiliary stacking table underneath the remaining stack of sheets can be moved out are.

In such a sheet feeder, it is be knows the one to a rake together connected skewers by a drive ge together under the rest of the sheet stack to move out. This leads to the end this movement which is still on the skewers lying part of the sheet stack with one Beat the thickness of the skewers speaking height to that below the rest New stack of sheets falls. So that the sheet feeder and in particular the suspension of the by the new sheet stack already heavily loaded Stacking tables with a significant addition load applied. To avoid damage The sheet feeder and the Suspension of the stacking table very high be resilient. These Problem is particularly big if it is  around large-sized sheets or around sheet metal standing bow, because then the weight of the rest of the sheet stack is particularly high is.

The object of the invention is therefore a Sheet feeder of the type mentioned at the beginning create that with relatively low resilience Construction safe for processing sheets or Suitable for stacking sheets of relatively high weight is.

This object is achieved according to the invention solved that the course of moving out of the individual skewers of the auxiliary stacking table at least under the rest of the sheet stack partially delayed. So that is done at the end of the outward movement of the skewers under the rest of the sheet stack opening the whole at the same time lower area of the rest of the sheet stack on the new sheet stack but a re relatively gentle, time-delayed hanging up of the individual Be supported by skewers pass the rest of the sheet stack onto the  new sheet stack. As a blow is avoided Structure of the sheet feeder not in addition to Inclusion of this high additional burden lays down what leads to a reduced build weight and a reduced size leads.

In addition, the rest of the sheet stack geared towards the new sheet stack placed.

According to the movement of the skewers can also easily move the individual skewers of the auxiliary stacking table under at least part of the rest of the sheet stack be done with a time delay.

The moving out hurries under the rest Sheet stack and / or the movement among the remaining stack of sheets of the outer skewers against the movements of the inner skewers ahead, the rest of the edition will be published Sheet stack symmetrical and thus with be particularly precise alignment. Here is the  The rest of the sheet stack in particular gently when the moving out under the remaining stack of sheets and / or movement among the rest of the stack of sheets medium skewers against the movements of the between the outer and middle skewers arranged skewers ahead.

An acceleration of the stack change ganges is achieved in that the An drove out at least one Part of the skewers with different Speed takes place, in particular the movement out at least in part the skewers at higher speed starts and along the path of movement reduced speed is continued. This means that in the first table phase of moving out the skewers Time can be saved while in the be load-critical final phase the slower Moving the skewers out gently the tray of the rest of the sheet stack supported.

The mirrors of the auxiliary stacking table are off  a position behind the stack of sheets below the remaining stack of sheets in sheet conveyors direction or under the stack of sheets movable against the sheet conveying direction drivable, so takes place at the exit movement of the auxiliary stacking table is a special one little impairment of the page out direction of the sheet stack. Furthermore the required space requirement of the Sheet feeder kept low.

Also to a small footprint as well for a simple and inexpensive construction it leads when the skewers share a common possess drive device. You can do this in simply put the skewers in the end positions onen their path of motion from the drive device can be uncoupled automatically.

A particularly simple structure of the aid stacking table is achieved in that the Drive device parallel to the Skewers extending and one skewer each has associated drive chains that each have a driver that in  a corresponding take of the assigned Spit can be engaged or disengaged, the Drivers differ in the direction of conveyance positions on the drive chains are arranged. The drive chain can at the ends of the Be Richly arranged pulleys from the spit be led away and the distance of the deflector roll the path of movement of the other Match skewer, the driver a Driving cams and driving a driving claw can be, the claw opening to the Drive chain is directed and in the skewer parallel extension range of the drive chain engages around the driving cam. By To order of the drivers z. B. using chains can be closed on the drive chains without great effort the positions of the carriers to be changed to each other.

Are the drive chains through them each assigned drive wheels movable bar, which are in parallel on a ge common rotatably drivable drive shaft are arranged, so only a small one  Space required for the drive shaft.

Can drive in both directions in a simple way the right drive shaft versibel be driven by an electric motor.

Is the auxiliary stacking table with upwards open, parallel in the conveying direction mutually extending grooves are formed, in which the corresponding cross section trained skewers are freely slidable are arranged with the least amount of work and expenditure of time and thus the lowest loading drive interruption an exchange of abge use skewers done. This is in particular important when processing sheet metal, because there is increased wear on the skewers he follows.

This is a simple drive possible that in the bottom of the grooves in groove longitudinal, continuous Slots are formed through which the Mit took to the drive chain protrude.  

To reduce the friction to be overcome Forces can form the walls of the grooves and / or the outer surface of the skewers with a rei low-exercise layer. This he possible to reduce the interpretation of the Drive device.

Forms the auxiliary stack carrying the skewers table together with the one from deflection wheels, An drive wheels, drive shaft and drive chains existing drive device vertically movable driven unit, so this unit is easy and quick mon animal. If the unit is defective this quickly through another assembly to be replaced so that the downtime be kept to a minimum due to repairs can.

Is the auxiliary stacking table or the unit at least in the area of the upper stroke of the Stacking table parallel and synchronous to Stackable table can be raised, can be activated, see above are before moving the skewers under the rest of the sheet stacks these be  riding in the exact, to drive under correct height so that the operating sub break until operation continues the auxiliary stacking table are kept low can.

To high despite processing of sheet stacks Weight one due to the strain he subsequent bending of the skewers slightly can hold in the conveying direction before Stacking table one horizontally across Carrier rail extending in the conveying direction same height as the auxiliary stacking table arranges to be in sync with the auxiliary is vertically movable stackable table can be driven and on the front in the conveying direction The ends of the skewers can be supported are.

In a simple training, the mounting rail be designed as a contact rail, according to Overlay of all skewers generates a signal through which the downward movement of the stack table is triggered and / or the drive device can be put out of operation. There  with the can at the earliest possible time Work of the sheet feeder with the auxiliary stack table operation continued and the operating interruption can be kept low.

Is a sensor reaching a certain remaining stack levels of the stacking table detectable and a signal for commissioning triggerable by the drive device the skewers of the same in this position chem height level as the stacking table auxiliary stacking table among the rest Sheet stack are movably driven, so this leads to an automatic activation of the auxiliary stacking table and thus for reduction interruption of operations.

To reduce the operating sub refraction due to automatic activation it also leads when through a sensor with vertical accelerated upwards sold it with a new sheet stack see stacking table reaching the bottom side of the remaining sheet stack through the Top of the new stack is detectable and  a signal to start up the drive device can be triggered by which the Skewers under the rest of the stack of sheets can be moved out.

An embodiment of the invention is in the drawing is shown and will follow the described in more detail. Show it

Fig. 1 a sheet feeder in the side view,

Fig. 2 is a rear view of the sheet feeder of Fig. 1,

Fig. 3 is an enlarged side view of the front portion of the auxiliary stacking table of the sheet feeder of Fig. 1,

Fig. 4 is a cross section along the line III-III of the portion of FIG. 3,

Fig. 5 is a fragmentary side view of a Spie SLI of the sheet feeder of Fig. 1 in the region of the driving pawl,

Fig. 6 is a plan view of the Spie SLI according to Fig. 5.

The sheet feeder shown in FIG. 1 has a stacking table 1 on which a pallet 2 with a sheet stack 3 rests. The stacking table 1 is in its lower position and has just been loaded with a new stack 3 . An auxiliary stacking table 4 on the stacking table 1 is located with a supported thereon remaining sheet stack 5 from which the respective uppermost sheet by means of a not shown sheet separator from the remaining stack of sheets 5 and liftable from a conveyor table 6 can be fed. The sheet reaches a printing press 7 via the conveyor table 6 .

In the conveying direction 8 behind the machine station 9 of the sheet feeder, a further sheet stack 11 is already stored on a lifting device 10 which, after the sheet stack 3 has been consumed, can be moved via a roller conveyor 12 into the illustrated position of the sheet stack 3 . The stacking table 3 is vertically movable in a known manner by a lifting device, not shown. The auxiliary stacking table 4 is suspended in three in the conveying direction at a distance from each other on lifting chains 13 of a hoist and can be driven vertically by the hoist be movable.

In the conveying direction 8 behind the rest of the sheet stack 5 , the auxiliary stacking table 4 has a guide table 14 , in which a plurality of skewers 15 are arranged in parallel and at a distance from one another in the direction opposite to the conveying direction 8 . The skewers 15 are arranged in upwardly open grooves 16 of the guide table 14 . In the position shown, the skewers 15 are in the extended operating position and carry the remaining stack of sheets 5 . For this purpose, they lie with their front end on a suspension rail 17 suspended from lifting chains 13 , which extends transversely to the conveying direction 8 and is always at the same height as the guide table 14 .

With the rear end, the skewers 15 rest on the guide table 14 . The guide table 14 forms an assembly formed as a structural unit of the auxiliary stacking table 4 . Under each groove 16 of the guide table 14 is arranged to a approximately over the length of the guide table 14 in the conveying direction 8 and extending around deflection rollers 18 parallel to the guide table 14 guided endless drive chain 19th On the drive chains 19 are arranged in the conveying direction 8 different positi ons driver cams 20 . In this driver cam 20 driving jaws 21 are one of the spikes 15 or disengaged, wherein the driving jaws 21 are arranged projecting away at the rear end portion 8 in the conveying direction of the spikes 15 downward. The entraining claws 21 project through continuous slots 23 which extend in the bottom 22 of the grooves 16 in the conveying direction 8 .

Since the drive cam are moved out 20 upon reaching one of the guide rollers 18 from the parallel to the guide table 14 level and thus also from the driving jaws 21, necessarily takes place in the two end regions of the movement path of the skewers 15 is a decoupling of the spikes 15 from its drive.

When the drive chains 19 are driven in the opposite direction later, the driver cams 20 are correspondingly moved back into the driver claws 21 and coupling is thus achieved.

The rear guide rollers 18 are rotatably arranged on a common rotatably drivable drive shaft 24 parallel to each other and thus form drive wheels for the drive chains 19th The drive shaft 24 is reversibly driven by an electric motor 25 , so that a chain tenantrieb in and opposite to the conveying direction 8 can be done in a simple manner.

Seen in the conveying direction 8 , the driver cams 20 of the two outer skewers 15 are located in the foremost position parallel and next to one another. At a distance behind the driving cam 20 of the two inner skewers 15 are arranged parallel to each other, while the driver cam 20 of which is arranged between the outer and inner spikes 15 skewers 15 is again at a distance therefrom. When moving the skewers 15 under the rest of the sheet stack 5 are thus the driver cam 20 of the outer skewers 15 , then at a distance from the driver cam 20 of the inner skewers 15 and in a further From the driver cam 20 was there between Skewers 15 are coupled into the corresponding entraining claws 21 and the associated skewers 15 are moved out from under the remaining stack of sheets 5 . In this order there is also an extension at the end of the movement strokes of the skewers 15 . This means that is first deposited the outer portions, the middle portion and lastly the lying between center type region and the outer regions areas of the remaining stack of sheets 5 on the ge now directly under the remaining stack of sheets 5 extended sheet stack. 3 A sudden drop of the rear loading area of the remaining sheet stack 5 on the sheet stack 3 is thus avoided. The file is placed gently and offset in the various areas.

As can be seen in particular in FIGS. 3 to 6, the skewers 15 have a rectangular cross section and taper to a point at their front end. The skewers 15 are encased with a low-friction layer 26 made of e.g. B. Teflon.

By means of screws 27 , the entrainment claw 21 is fastened to the underside of the skewer 15 shown with the opening 28 directed downward. As shown in FIG. 4, is located in the opening 28 of the entrainment of the claw 21 attached to the drive chain 19 with the slave cam 20. The area of each groove 16 is designed as a separate guide track 29 . The guide tracks 29 to the guide table 14 are connected to one another via cross members 30 .

The sheet feeder works like follows:

If, as shown in FIG. 1, a new sheet stack 3 is placed on the stacking table 1 and no remaining sheet stack 5 lies on the extended skewers 15 , the stacking table 1 is raised by a short stroke.

Sensors, not shown, sense the alignment of the sheet stack 3 since and give appropriate signals to a control unit. This controls, if necessary, a side alignment drive, not shown, which moves the entire stacking table 1 accordingly laterally.

Now the stacking table 1 is raised so far that the top sheet is almost at working height. Through a presser foot not shown, the level of the top sheet is then scanned in a known manner and the stacking table 1 with the sheet stack 3 is gradually raised until the top sheet has finally reached the working height. This is detected by a sensor and by means of the signal supplied to the control unit, the sheet separator direction of the sheet feeder is put into operation.

According to the sheet removal, which is scanned by the presser foot, the stack table 1 is gradually raised until there is only a certain remaining stack height.

During the last part of the lifting movement of the stacking table 1 , the auxiliary stacking table 4 was actuated in parallel and synchronously with it so that it could be moved vertically, so that the stacking table 1 and auxiliary stacking table 4 were located at the same height. Thus, when reaching the rest of the stack height, the electric motor 25 is put into operation and by means of the drive chains 19 the skewers 15 are moved under the sheet stack 3 in the area of the pallet 2 .

When all the skewers 15 have reached the front position and thus lie with their front ends on the support rail 17 , the driver claws 21 of the skewers 15 being decoupled from the driver cams 20 , a signal is generated by the support rail 17 designed as a contact rail and the control unit fed through which both the downward movement of the stacking table 1 and its lateral alignment in the central neutral position is triggered and the operation of the electric motor 25 is ended.

After the empty pallet 2 has been removed, the further sheet stack 11 is moved over the roller conveyor 12 onto the stacking table 1 . There follows a lateral position query of the sheet stack and, if appropriate, a corresponding direction from the stacking table 1 . Then he follows, as already described at the beginning, a short lifting, a further lateral question from the sheet stack and, if necessary, a lateral alignment. Now the stacking table 1 is raised at high speed until the top sheet is just below the skewers 15 . The lifting movement takes place slowly for the last centimeters until the sheet stack abuts on the skewers 15 .

Driving under the skewers 15 leads to a relief of the support rail 17 , which conducts a corresponding signal to the control unit, whereby the electric motor 25 is now put into operation in the opposite direction. By moving the drive chains 19 first with the slave cam 20 of the outer drive chains 19 into engagement in the openings 28 of ent speaking driving claws 21 and move the skewers 15 under the rest of the sheet stack 5 out. Time offset from the beginning of the loading out of the outer moving skewers 15 takes the same with the central spikes 15 and, in turn, also displaced in time with the SEN between the outer and middle Spie 15 located skewers 15 °.

The first part of moving out the skewers takes place at a higher speed and the last part of moving out at a low speed. By the offset moving out of the spikes 15 of the rest Liche sheet stack 5 reaches the areas of the various skewers at different times on the underlying sheet stack 3 to the support so that the sliding down of the skewers 15 to the sheet pile 3 takes place gently.

When the skewers have reached their extended end position, they automatically disconnect from their drive. Now the electric motor 25 is also switched off.

By capturing the different positions ones and states by means of sensors complete batch changes by the tax authorities automatically controlled.

Claims (22)

1. Sheet feeder with a stacking table for receiving a sheet stack, with a sheet separating device. which is arranged above the stacking table and through which the top sheet of the sheet stack can be detected and fed to a further processing machine, the stacking table keeping the top sheet in each case vertically movable at a certain height, with an auxiliary stacking table which has several at a distance in parallel next to each other in a horizontal plane has skewers which can be moved by a drive device under the remaining sheet stacks carried by the stacking table, the auxiliary stacking table taking over the load of the sheet stack and its uppermost sheet being drivable vertically at the specific height level, while the stacking table for receiving a new sheet stack can be lowered into its lowest position and then raised to the bottom sheet of the rest of the sheet stack until the uppermost sheet of the new sheet stack rests, and the skewers of the auxiliary stacking table under the remaining B Ogenstapel are moved out bar, characterized in that the course of the out movement of the individual skewers ( 15 ) of the auxiliary stacking table ( 4 ) under the remaining sheet stack ( 5 ) is at least partially staggered. 2. Sheet feeder according to claim 1, characterized in that the movement of the individual skewers ( 15 ) of the auxiliary stacking table ( 4 ) under the remaining sheet stack ( 5 ) is at least partially offset in time. 3. Sheet feeder according to one of the preceding claims, characterized in that the out movement under the remaining sheet stack ( 5 ) and / or the movement under the remaining sheet stack ( 5 ) of the outer skewers ( 15 ) with respect to the movements of the inner skewers ( 15 ) hurries ahead. 4. Sheet feeder according to one of the preceding claims, characterized in that the outward movement under the remaining sheet stack ( 5 ) and / or the movement under the remaining sheet stack ( 5 ) of the central skewers ( 15 ) relative to the movements of the between the outer and middle spears (15) arranged skewers (15) is ahead. 5. Sheet feeder according to one of the preceding claims, characterized in that the drive of the out movement occurs at least in part of the skewers ( 15 ) at different speeds. 6. Sheet feeder according to claim 5, characterized in that the outward movement at least in part of the skewers ( 15 ) begins at a higher speed and is continued at a reduced speed in the course of the movement path. 7. Sheet feeder according to one of the preceding claims, characterized in that the skewers ( 15 ) of the auxiliary stacking table ( 4 ) from a position behind the sheet stack ( 3 ) under the rest of the sheet stack ( 5 ) in the sheet conveying direction ( 8 ) or under the Sheet stack ( 5 ) are drivable out of the sheet conveying direction ( 8 ). 8. Sheet feeder according to one of the preceding claims, characterized in that the skewers ( 15 ) have a common drive device. 9. Sheet feeder according to one of the preceding claims, characterized in that the skewers ( 15 ) are automatically decoupled from the drive device in the end positions of their path of movement. 10. Sheet feeder according to claim 9, characterized in that the drive device extends parallel to the skewers ( 15 ) and each has a skewer ( 15 ) associated drive chains ( 19 ), each having a driver, which in a corresponding driving the assigned skewer ( 15 ) can be coupled in or out, the drivers being arranged in different positions in the conveying direction ( 8 ) on the drive chains ( 19 ). 11. Sheet feeder according to claim 10, characterized in that the drive chain ( 19 ) to the ends of the spit ( 15 ) parallel area angeord Neten pulleys ( 18 ) of the skewer ( 15 ) is Wegge and the distance between the pulleys ( 18th ) corresponds to the path of movement of the spit ßes ( 15 ), the driver is a driver cam ( 20 ) and the driver is a driver claw ( 21 ), the claw opening ( 28 ) is directed to the drive chain ( 19 ) and in parallel to the skewer ( 15 ) Erstreckungsbe range of the drive chain ( 19 ) encompasses the driver cam ( 20 ). 12. Sheet feeder according to claim 10, characterized in that the drive chains ( 19 ) are movably driven by their respective associated drive wheels, which are arranged in parallel side by side on a common rotatably drivable drive shaft ( 24 ). 13. Sheet feeder according to claim 12, characterized in that the drive shaft ( 24 ) is reversibly electromotively drivable. 14. Sheet feeder according to one of the preceding claims, characterized in that the auxiliary stacking table ( 4 ) with upwardly open, in För derrichtung ( 8 ) parallel to each other erstrec Kenden grooves ( 16 ) is formed, in which the corresponding cross-section formed skewers ( 15 ) are freely movable. 15. Sheet feeder according to claim 14, characterized in that in the bottom ( 22 ) of the grooves ( 16 ) extending in the groove in the longitudinal direction, continuous slots ( 23 ) are formed, through which the entrainment to the drive chain ( 19 ) protrude. 16. Sheet feeder according to claim 14, characterized in that the walls of the grooves ( 16 ) and / or the outer surfaces of the skewers ( 15 ) are provided with a low-friction layer ( 26 ). 17. Sheet feeder according to one of the preceding claims, characterized in that the auxiliary stacks ( 4 ) carrying the skewers ( 15 ) together with the drive device consisting of deflection wheels ( 18 ), drive wheels, drive shaft ( 24 ) and drive chains ( 19 ) are vertical movable drivable unit forms. 18. Sheet feeder according to one of the preceding claims, characterized in that the auxiliary stacking table ( 4 ) or the structural unit at least that in the range of the upper stroke of the stacking table ( 1 ) can be raised and moved in parallel and synchronously with the stacking table ( 1 ). 19. Sheet feeder according to one of the preceding claims, characterized in that in the conveying direction ( 8 ) in front of the stacking table ( 1 ) a horizontally transverse to the conveying direction ( 8 ) extending support rail ( 17 ) is arranged at the same height as the auxiliary stacking table ( 4 ) is, which can be driven vertically and synchronously with the auxiliary stacking table ( 4 ) and on which the front ends of the skewers ( 15 ) in the conveying direction ( 8 ) can be supported. 20. Sheet feeder according to claim 19, characterized in that the support rail ( 17 ) is designed as a contact rail, which generates a signal after support of all skewers ( 15 ) by which the downward movement of the stacking table ( 1 ) can be triggered and / or the drive unit direction can be deactivated. 21. Sheet feeder according to one of the preceding claims, characterized in that the reaching of a certain residual stacking level of the stacking table ( 1 ) can be detected by a sensor and a signal for starting the drive device can be triggered, through which the skewers ( 15 ) of the in this position Auxiliary stacking table ( 4 ) located at the same height level as the stacking table ( 1 ) can be driven to move under the remaining stack of sheets ( 5 ). 22. Sheet feeder according to one of the preceding claims, characterized in that a sensor with vertical accelerated upward drive of the stacking table provided with a new sheet stack ( 1 ) reaches the underside of the remaining sheet stack ( 5 ) through the top of the new stack ( 3rd ) can be detected and a signal for starting the drive device can be triggered, through which the skewers ( 15 ) can be moved out from under the remaining sheet stack ( 5 ).