WO2000051925A2 - Method and device for separating flat postal items - Google Patents

Abstract

The invention relates to a pick-off element that comprises a plurality of pick-off belts (1, 2) that run on rollers and are driven in a controlled manner. At least one pick-off belt (2) is provided with sections that have a repeatedly reusable, adhesive surface.

Description

description

Method and device for separating flat mail items

The invention relates to a method and a device for separating flat mail items from a stack according to the preambles of the independent claims.

As part of shipment distribution and processing processes, the shipments are transported in batches in containers and in processing machines, e.g. Sorting machines, processed individually. To do this, the consignments must be separated from the stacks.

So far, the so-called friction separation has mainly been used to pull the items off the stack. A roller or belt is provided with a rough surface in order to achieve a high coefficient of friction with the exposed surface of the last shipment in the stack.

The moving belt or the rotating roller convey the last consignment perpendicular to the stack axis away from the stack if there is a frictional connection between the belt or roller and the surface of the consignment. For the frictional connection, static friction is always sought to ensure reliable funding.

The static friction can only be guaranteed by a contact pressure that is sufficiently high even for different mail item surfaces with different friction coefficients.

The contact pressure between the exposed surface of the last shipment in the stack and the friction belt or friction roller is generated today in various ways: by the stack, which presses the last item of mail against the friction surface (for example deduction from below) (US 5,363,971), by a conveyor device which pushes the stack and presses it against the friction surface (standing goods) (US Pat. No. 5,292,114),

- By a negative pressure, which sucks the surface of the mail piece to the friction surface through bores in the roller or belt (deduction from above and support for all other types of deduction) (US 3,861,669).

The disadvantage here is that, because of the unknown coefficient of friction, the contact pressure must be chosen high enough to guarantee a safe withdrawal. In particular when deducting from below, this leads to undesirably increased friction between the last and penultimate mail item, which leads to frequent double deductions. The frictional force must be maintained during the deduction so that a deduction can take place and can only be generated by means of a normal force. Another disadvantage is the known generation of force by negative pressure, since it also leads to frequent double deductions, namely when the next shipment is also sucked in through an air-permeable, thin shipment.

The problem with all known solutions is in any case that the frictional force, which is dependent on the contact pressure and the coefficient of friction, ultimately represents the only force that can be used for the triggering. Both the required contact pressure and the friction coefficient between the free surface of the last item and the friction surface are often unknown and variable during the pull-off. There are few successful approaches to determine or at least estimate these two quantities with great effort.

Remedial action is sometimes attempted by shingling the stream of material and grasping the first free edge of the foremost shipment by friction. Here, however, the problem is shifted back to the clapboard. At some point the surface of the shipment has to be attacked frictionally, which requires normal forces during the movement (US 4,523,753). The invention specified in independent claims 1 and 16 is therefore based on the object, while avoiding the disadvantages of the prior art, of reliably separating a stack of flat mail items by pulling off an outer mail item by means of revolving pulling belts with as little stress on the mail items as possible.

Advantageous refinements of the invention are set out in the subclaims.

The invention is based on the idea of using a driving force generated by a releasable adhesive connection in order to avoid or reduce the pressing force previously required for the necessary friction force during the pull-off process between the item to be pulled and the pull-off bands. The free surface of the last shipment of the stack and the adhesive surface do not touch until immediately before the print. If a deduction is to be made, the two surfaces are briefly brought into contact by an external force. This contact must be as flat as possible and with sufficient contact pressure. After the contact between the two surfaces has been established, they adhere to each other through the adhesive. The external force can now be removed without removing this liability. Withdrawal can now take place in the unloaded state, with the surfaces remaining in a non-positive connection. After the adhesive connection has been made, constant pressure is no longer required. This in turn means that the double pull-off risk that occurs when this pressure force is generated via the stack pressure is reduced by interlocking the mail items, or that when the pressure force is generated, for example with the aid of a negative pressure, the existing double pull-off risk due to the suction of two mail pieces if the first one Consignment is thin and partially permeable to air, is reduced by at least a strong reduction in the suction pressure. At the end of the straps there is a separation of the reusable adhesive tape from the removed item.

In order to reduce the risk of double deduction as much as possible, it is advantageous to dispense with pressing the consignment to be deducted from the deduction member when the consignments are withdrawn.

For easy separation of the withdrawn mailing from the one or more pulling belts rotating on deflection rollers with adhesive effect, it is advantageous to guide the mailings in the pulling direction beyond the pulling belts with adhesive effect. As a result, the separation takes place as a peeling at the last deflecting rollers, in that take-off belts leave the level on which they run together with the item and pass through a radius that removes them from the level of the item. The program continues straight in the original direction of the conveyor belt. In this way, the adhesive is removed and the mailing and release tapes are separated from one another with an adhesive effect.

The consignments are advantageously guided on both sides of the take-off belts. For the safe separation of the mail items from the take-off belts with an adhesive effect, a wiper can also be arranged on the deflection rollers of the take-off belts with an adhesive effect in the take-off direction.

In order to reduce the stress on the mail items to be removed, they are advantageously guided by rotating guide belts driven in the same direction as the take-off belts with an adhesive effect.

It is also advantageous to support the pull-off process with a further entraining force, which is generated by friction. It is advantageous to produce the friction connection by means of the guide bands provided with a corresponding covering. The contact pressure required for the friction connection can be generated at least partially by a negative pressure on the side of the take-off element to avoid harmful stack pressure. In a further embodiment, the deduction member can act on the mail item to be deducted at the same time during the deduction or at the same time by friction and detachable adhesive connection.

It is particularly advantageous for the processing of very different mail items with relatively heavy and thick mail items first to act on the item to be removed by releasable adhesive connections and, in the event of slip measured with sensors, to add a pulling force to the removal member caused by friction. In order to keep this frictional force as low as possible, it can be changed by continuously changing the contact pressure during the pull-off process in such a way that the mail items are prevented from slipping.

With regard to the lowest possible implementation effort, it is advantageous to generate the short-term contact force required for the adhesive by means of a negative pressure which pulls the item to be separated onto the trigger tapes. This can be done in that the friction belts and / or the pull-off tapes have recesses with an adhesive effect and one or more suction chambers with switchable and changeable negative pressure are arranged directly behind the belt sections running in the pull-off plane through the recesses on the mail items to be removed. Via the negative pressure, the contact pressure for realizing the adhesive and the pressure force necessary for the frictional entrainment are generated as required.

In a further embodiment, the short-term contact force required for the gluing can be generated by a corresponding short-term movement of the take-off element against the stack of mail items and / or of the stack of mail items with the item to be removed against the take-off element. The trigger tapes are adhesive to produce these movements or supporting elements which move and hold the stack of mail items movably and are connected to a correspondingly controlled drive device.

In order to minimize the risk of the next consignment being taken along by the adhesive tape or tapes during the removal process, the tape can be provided with an adhesive surface in sections with an adhesive effect in the direction of rotation. The length of these sections advantageously corresponds at most to the length of the shortest shipment and the length of the distances between these sections at least to the length of the largest shipment to be deducted. This ensures that the next shipment of the stack does not come into contact with the adhesive surface during peeling.

So that the adhesive properties of the adhesive surfaces can be kept almost constant during operation, it is also advantageous to clean the trigger tapes from adhesive dirt particles with an adhesive effect during circulation. For this purpose, the take-off belt or belts go through a cleaning and then a drying station during the circulation.

The invention is then explained in more detail in an exemplary embodiment with reference to the drawings. Show

1 shows a perspective schematic illustration of a removal device FIG. 2 shows a schematic illustration of the stack feed with the removal level FIG. 3 shows a top view of a schematic illustration of the removal device with cleaning and drying stage

According to FIG. 1, the trigger element consists of two outer friction trigger bands 1 and a centrally arranged trigger band 2 with adhesive effect. The two friction trigger belts 1 sit on two common axes and are driven together. The trigger tape 2 with adhesive effect has its own tape guide and its own drive. The axes of the friction belt 1 are arranged in a stationary manner, the axes of the belt 2 with adhesive effect can be moved with a drive in the direction of the stack of mail, as indicated by the arrow 3. The total area of the deduction corresponds approximately to the dimensions (length times width) of the smallest shipment.

The trigger tape 2 with adhesive effect is not coated over the entire length, but only in sections. The length of a coated section corresponds to the length of the tape, which is opposite the smallest item in the idle state.

The distances between the sections are at least as long as the length of the largest consignment to be deducted. This can reduce the risk of double deductions. To further prevent double deductions, the trigger member also has a known wiper, not shown here, as can be seen in DE 197 29 430 AI.

The plane which the take-off belt 2 forms with an adhesive effect parallel to the surface of the item is shorter in the take-off direction than the plane correspondingly formed by the friction take-off belts 1. As a result, peeling 6 of the consignment of extractor tape 2 after the take-off has been ensured at the last roll in the take-off direction, on which the take-off belt 2 is deflected out of this plane with adhesive effect, while at the same time further transporting the shipment through the friction trigger belts 1 to the subsequent one Transport device.

A take-off cycle now runs as follows: The take-off belt 2 with adhesive effect has moved back from take-off level 7 (FIG. 3), so it has no contact with the item to be removed. A coat with the adhesive layer teter section of the deduction belt 2 is located opposite the consignment to be deducted. The foremost consignment of the stack to be separated, which lies against the extraction surface without force, is sucked onto the latter with a vacuum which acts through the recesses in the friction extraction belts 1. The trigger tape 2 is now moved with an adhesive effect with a rapid movement towards the trigger level 7, represented by the arrow 3. This creates the necessary contact pressure between the mailpiece and the trigger belt 2 and the drive for this movement is switched off. In another possible trigger variant, an adhesive section of the trigger tape 2 lies in the trigger plane 7 and is in contact with the foremost shipment. The frontmost consignment to be pulled against the trigger surface is now applied to the friction trigger belts 1 and thus to the trigger belt 2 with an adhesive effect, which occurs in the located on the same level. The vacuum must be selected so that the contact pressure required for the adhesive is generated. In addition, the trigger tape 2 can also be provided with recesses on the adhesive sections and the suction chamber can also be arranged behind the trigger tape 2 with the adhesive effect. After the consignment to be drawn sticks to the trigger belt 2, the negative pressure is switched off. Then the three take-off belts 1, 2 are driven at the same speed in the take-off direction and the foremost mail item to be removed is carried along by the adhesive. Due to the movement of the trigger tape 2 with the adhesive effect, the following non-adhesive part is transported into the trigger plane. This prevents the following consignment from being unwantedly transported by gluing.

During the removal process, sensors, for example light barriers, are used to monitor whether the item to be removed has slippage with respect to the removal belts 1, 2. If this is the case, a negative pressure is generated in the friction trigger belts in the height switched on that the further transport is carried out slip-free.

Before the consignment has been completely peeled off from the adhesive pulling belt 2, the friction pulling belts 1 with their rear parts have to take over the further transport. This is the case at the latest after the minimum shipment length. Either the vacuum is switched on in the rear part or pressure rollers take over the generation of the frictional force. At the end of these two friction trigger belts 1, the shipment is completely isolated and can be transferred to a transport device. The two take-off belts 1 are transported until a light barrier detects the rear free edge of the removed mail item transferred to the transport device. After the transfer to the subsequent transport device, the adhesive trigger tape 2 is moved back from the trigger level 7 and is therefore no longer in contact with the foremost shipment. In this state, the trigger tape 2 is driven with an adhesive effect until the next adhesive section lies exactly in the trigger area. If the rear edge of the individual item has left the take-off area, the take-off belt 2 is moved back into the take-off level 7 with an adhesive effect and the cycle starts again.

Silicone with a low Shore hardness, which is set to be “sticky”, is preferably used as the material for the adhesive surface. Such silicone is e.g. of so-called lint rolls, which are used to clean fabrics, are known. The "sticky" silicone has the advantage that dirt with dust or paper particles can be removed by simply washing it off. The trigger tape 2 can be regenerated with an adhesive effect.

Depending on the amount of dust, the silicone surface will deteriorate over time due to adhering dust particles. In order to regenerate the silicone surface, the trigger tape 2 or the adhesive sections must be replaced by a Cleaning stage are carried out in which the adhering paper particles are removed from the silicone surface in a liquid bath using known means. The cleaning can be done by spraying from nozzles, by brushing or by moving the belt in the bath or by ultrasound support. Water is preferably used as the liquid. After the water bath, the take-off belt 2 (or the surface) is dried. This is done, for example, by blowing off with compressed air or by wipers that wipe off the liquid. Silicone does not absorb water itself. Because silicone is hydrophobic, the water rolls off the surface very well. Heated air supports drying.

After this cleaning process, the original peeling effect is restored. Cleaning takes place after each deduction. The take-off belt 2 is continuously guided through a cleaning device 4 and a subsequent drying device 5 and advanced by the appropriate amount with each take-off.

The stack feed is shown schematically in FIG. 2. The stack of mail items 8 stands on a loading table which runs slightly obliquely upwards. The stack of mail items 8 is inclined slightly backwards and is supported by a support bracket 9 and pushed to the trigger point. The support bracket 9 is fastened to a conveyor belt 10 which is driven in a controlled manner. The inclination was chosen so that as little pressure as possible was exerted on the deduction area by the weight of the mail items.

In the last part before the take-off surface, the transport surface drops off with the conveyor belt 10, so that drop-shaped mail items from the cross section are pressed by the holding support 9 approximately at the center of the take-off surface 11. The horizontal area directly in front of the withdrawal surface 11 is as wide as the maximum mailing thickness. In order to adapt to different mailing spectrum, the inclination of the trigger surface 11 and thus of the trigger element adjustable. The feed of the conveyor belt 10 with the holding support 9 is regulated by sensors which are located in the take-off plane. The foremost mail item to be pulled is on the horizontal area of the stack feed directly in front of the take-off surface 11 and touches it almost without force. The deduction is made from the drawing level to the rear.

Claims

claims 1.Procedure for separating flat mail items from a stack with a take-off device running in the conveying direction in the form of one or more controlled driven take-off belts, with which the foremost mail item of the stack is pulled off from a standstill and transferred to a subsequent transport system , wherein the stack of mail items is fed parallel to the level of the take-off belt, characterized in that by means of a releasable adhesive connection, a driving force is generated between the item to be removed and at least one take-off tape (2), and at the end of the take-off tapes (2) the removed item from these take-off tapes (2) has an adhesive effect. is separated. 2. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that during the peeling with adhesive force, the mail item to be peeled off is not pressed against the trigger member. 3. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that for establishing the adhesive connection, a contact pressure between the or the still standing release tapes (2) with adhesive effect and the mail item to be removed is generated. 4. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that for separating the withdrawn mail from the one or more deduction tapes (2) with adhesive effect this Shipment in the trigger level (7) on the trigger tapes (2) with adhesive effect in the direction of the trigger. 5. The method of claim 4, d a d u r c h g e k e n n - z e i c h n e t that the consignment to be deducted on both sides of the Trigger tapes (2) with adhesive effect is performed. 6. The method of claim 5, d a d u r c h g e k e n n z e i c h n e t that the consignment to be deducted by means of in the same direction as the deduction belts (2) with adhesive effect driven, rotating guide belts (1) is guided. 7. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that during the separation, a drag force caused by friction is additionally generated between the trigger element and the consignment to be deducted. 8. The method according to claim 6 and 7, d a d u r c h g e k e n n z e i c h n e t that the friction connection is generated by the guide bands (1). 9. The method according to claim 7 or 8, d a d u r c h g e k e n n z e i c h n t that the contact pressure necessary for the frictional connection between the take-off member and the mail item to be drawn off is formed at least in part by a pressure on the side of the take-off member between the foremost mail item of the stack and the take-off member. 10. The method of claim 7, d a d u r c h g e k e n n z e i c h n e t that the trigger member acts simultaneously and / or temporally separated by releasable adhesive connection and friction on the mail item to be deducted during the deduction. 11. The method of claim 10, d a d u r c h g e k e n n z e i c h n e t that the trigger member first acts on the item to be removed by releasable adhesive connection and, when the slip of the item to be removed is measured, a driving force caused by friction is activated on the item. 12. The method according to claim 10, characterized in that the additional driving force generated by friction of the trigger member by varying the Contact pressure is changed during the pull-off process so that slipping of the mail is just prevented. 13. The method of claim 4, d a d u r c h g e k e n n - z e i c h n e t that the short-term pressure force required for the gluing is generated by a negative pressure pulling the item to be separated to the pulling belts. 14. The method of claim 4, d a d u r c h g e k e n n - z e i c h n e t that the short-term contact force required for the gluing is generated by briefly moving the take-off member against the item to be removed and / or by briefly moving the stack with the item to be taken off against the take-off member. 15. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that the trigger tapes (2) are cleaned with adhesive effect during their circulation of adhering dirt particles. 16. Device for separating flat mail items from a stack, which can be fed with a feed device parallel to the take-off plane to a take-off member running in the conveying direction, the take-off member having one or more controlled, driven take-off belts, each of which comes from a standstill the foremost shipment of the stack can be pulled off and fed to a subsequent transport system, characterized in that at least one take-off belt (2) at least partially has a reusable adhesive surface. 17. The apparatus according to claim 16, characterized in that the circumferential trigger tapes (2) are provided with an adhesive effect in sections in the circumferential direction with an adhesive surface. 18. The apparatus of claim 17, d a d u r c h g e k e n n z e i c h n e t that the length of the sections of the trigger tapes (2) with adhesive surface corresponds to a maximum of the length of the shortest shipment. 19. The device according to claim 17, so that the length of the distances between the sections of the trigger tapes (2) with adhesive surface corresponds at least to the length of the largest mail item to be removed. 20. The apparatus of claim 16, d a d u r c h g e k e n n z e i c h n e t that on the deflecting rollers of the trigger belt (s) (2) with adhesive effect in the pull-off direction a stripper aligned in this for safe separation of the withdrawn mail from the trigger belt (s) (2) with adhesive effect. 21. The apparatus of claim 16, d a d u r c h g e - k e n n z e i c h n e t that on both sides of the trigger tape or tapes (2) are provided with adhesive effect in the take-off plane in the take-off direction extending beyond the end of the take-off tapes with adhesive effect. 22. The apparatus of claim 21, d a d u r c h g e k e n n z e i c h n e t that the guide means are circumferential friction trigger bands (1) whose effective area lies in the trigger plane (7). 23. The apparatus according to claim 22, characterized in that the friction trigger tapes (1) and / or the trigger tapes (2) have recesses with an adhesive effect and directly behind the strip sections running in the withdrawal plane through the recesses acting on the items to be withdrawn suction chambers with switching and changeable vacuum are arranged. 24. The apparatus of claim 16, d a d u r c h g e k e n n z e i c h n e t that the or the trigger belts (2) are movably mounted perpendicular to the trigger plane with adhesive effect, and that a controlled drive device is provided for performing this movement. 25. The apparatus of claim 16, d a d u r c h g e k e n n z e i c h n e t that the take-off tapes (2) are guided with an adhesive effect in their circulation through a cleaning and drying device (4,5), in which dirt particles adhering to the adhesive surfaces are washed off and then dried. 26. The apparatus of claim 16, d a d u r c h g e - k e n n z e i c h n e t that sensors for determining Slip of the consignment located on the trigger element during the trigger is provided on the trigger belts (1, 2). 27. The device according to claim 24, so that sensors are provided for determining the distance from the plane of action of the trigger tape or tapes (2) which is parallel to the surface of the item and which has an adhesive effect from the take-off plane.