DE202010000469U1 - Arrangement for the production of transport pallets made of plastic - Google Patents

Abstract

Arrangement for the production of transport pallets of plastic, in particular of recycled plastics, comprising at least one casting station (2) for filling at least one closed mold (7) with plastic, the casting station comprising an extruder (2.1) for providing creamy liquefied plastic material and a distributor (2.3 ) having at least one docking opening (2.14) for introducing the plastic material into a mold (7), further comprising at least one cooling zone (3) for cooling the mold until solidification of the plastic material and a demolding station (4) for opening the mold, removing the mold formed from the plastic material transport pallet and resealing the mold, characterized in that the arrangement further comprises a transport device (1) for automated transport of the at least one mold (7) from the casting station (2) through the cooling area (3) to the demolding station (4) and back to the casting station (2).

Description

The The invention relates to an arrangement for the production of transport pallets made of plastic.

From the DE 198 21 397 A1 is an intrusion process for producing parts made of recycled plastics, which have a high compression and a high strength. In this case, a plasticized plastic melt from an extruder is introduced into the shaping cavity of an extrusion mold produced from an extruded semi-finished product of an aluminum alloy with high heat capacity by injection molding. The filling of the intrusion mold is stopped as soon as a previously set ground pressure is reached. For alternating filling of several forms of intrusion two switchable distributor nozzles are provided. The cooling of the intrusion mold is carried out after removal from the extruder in a separate step by the action of atmospheric air.

In the EP 2 058 104 A2 discloses an apparatus and a method for the production of transport pallets, wherein in an extruder portioned a mixture of recycled plastics and fibrous material, liquefied by heating creamy and is conveyed via the screw conveyor of the extruder in a cartridge. During this process, an empty aluminum mold is connected to a manifold. Subsequently, the amount of material accumulated in the cartridge is pressed with a pressure of less than 50 bar from the cartridge into the aluminum mold. When the aluminum mold is full, it is decoupled from the manifold and cooled with water for curing as the cartridge is being refilled from the extruder. Meanwhile, the next empty aluminum mold is connected to the manifold and the process is repeated. For alternately docking and filling two molds, two cartridges from a common extruder can be charged with the mixture. To produce a foam structure of the finished transport pallet, a blowing agent may be added to the mixture which has the property of producing a gas at certain temperatures.

at the known devices for the production of transport pallets made of plastic are usually filling, Cooling, opening and closing the Mold as well as the removal of the pallet made manually or monitored. This procedure is complicated and often not sufficiently reproducible. An automation of the Procedure is not provided in the known devices.

It The object of the present invention is an improved arrangement to propose for the production of plastic transport pallets, in particular an arrangement for the automated production of transport pallets made of plastic. It is another object of the present invention to provide a To provide mold for use in such an arrangement.

These Task is by an arrangement as well as by a casting mold as stated in the independent claims.

A Inventive arrangement for automated Production of transport pallets comprises a transport device, a casting station, a cooling area, a demoulding station and a buffer area.

The Transport device comprises in particular a circumferential track for guiding trolleys, each of which has a separate Drive for propulsion along the rail may have. In addition to the Running rail is advantageously arranged a busbar to transfer the for the operation of trolleys required electrical energy as well as for transmission of control signals.

each Trolley has a holder for receiving at least one mold on. The holder comprises fastening means, for example a or several hooks in which the shape with appropriate eyelets can be hung. The mold (hereafter also referred to as "form" for short) can by the Fixing means detachable or not releasable with be connected to the trolley. The fasteners can be arranged on ropes or chains that make it possible the shape at a distance below the trolley or below to transport the running rail. The bracket may further include lifting means include, whereby the distance is variable. Especially may be a pair of ropes or chains by means of which a form is suspended lowered or raised by motor. The lifting means can advantageously controlled separately for each trolley become.

In particular, the transport device is designed in such a way that the molds can be transported from a casting station through a cooling region to a demolding station, and from the demoulding station through a buffer region back to the casting station. Advantageously, the transport device is designed for this purpose with a substantially horizontally arranged in the form of an oval track, which is attached, for example, to a hall ceiling or stored by means of supports in a sufficient height. It can be arranged at or near the one end of the oval, the casting station and at or near the other end of the demolding station, and zwi casting station and demolding station on one side of the oval of the cooling area and on the other longitudinal side of the buffer area.

The Casting takes place in a casting station. The casting station includes an interface for docking the molds, an extruder for providing the pasty plastic mass and a manifold for introducing the plastic compound into a docked form.

Of the Extruder is a device for plastic liquefaction and promotion. In contrast to the injection molding technology are here no facilities for generating particularly high pressure required. The extruder can, for example, a heated tube and a conveyor screw driven therein driven by an electric motor include. The pasty plastic mass is in the extruder produced in particular from a granulate made from recycled plastic, fed to the extruder from a reservoir becomes.

One The outlet of the extruder is connected to a distributor. For filling The molds can each have at least one mold to the casting station or docked to the distributor. The distributor consists of at least one pipeline that may be heated to solidify the pasty plastic mass during the filling process or in case of waiting times when connecting and disconnecting and changing to avoid the forms. As the forms usually have a majority from filling holes to a rapid, uniform and to allow complete filling of the mold For example, the manifold is preferably a plurality of conduits and corresponding branches formed. Accordingly, can a plurality of heaters may be provided to increase the viscosity to avoid the plastic mass in the pipelines and branches or limit.

According to a preferred embodiment of the invention, a buffer is also provided for temporarily storing and metering the plastic mass produced by the extruder before it is filled into the mold. For this purpose, the buffer is connected on the one hand to the outlet of the extruder and on the other hand to the distributor. In particular, the temporary storage device has a variable volume and, for this purpose, can be designed as a cylinder with a movable piston. The buffer can be advantageously designed such that the buffered plastic mass is passed in such a way to the manifold that the first passed from the extruder to the buffer memory material is also first passed from the buffer to the distributor (FIFO function). The inter mediate memory can be heated so that it has the temperature required for maintaining the plasticity of the plastic material. Extruders and buffers can, for example, as in the EP 2 058 104 A2 be described described.

Furthermore, it is preferred that a connection for supplying a blowing agent is also provided on the extruder, in order to supply it during the production of the pasty plastic compound. From the extruder, therefore, a liquefied mixture of the plastic and the blowing agent is promoted. The blowing agent develops at the temperature of the liquefied mixture during further processing and possibly during its residence time in the buffer a gas distributed in small bubbles, which gives the transport pallet a foam structure, as in EP 2 058 104 A2 described in more detail. In this way, a certain pore-containing or hard foam-like structure can be achieved and be significantly reduced by the associated reduction in density for a given volume of material required for the pallets and thus the empty weight of the pallets. Characterized in that the blowing agent is supplied in the extruder and that it can act in particular with a defined expansion or residence time and under a defined, allowing sufficient bubble expansion, relatively low pressure, in particular in combination with a relatively low-pressure and slow supply of the foamed plastic mass in the shape, both an optimal expansion of less effective blowing agent and a closing of the surface-side pores can be achieved before the final solidification in order to achieve a sufficiently smooth, compact and also satisfactory from a hygiene aspects outer skin.

alternative For this purpose, the addition of the propellant also at a later Time, for example, in the promotion to the cache or when the plastic compound is dispensed into the mold. As well can not use foamed plastics become. In the context of the present invention can plastics processed with and without the addition of reinforcing fibers However, a use of plastics without added fiber is, however prefers.

According to a further preferred embodiment of the invention, closures are provided both at the outlet of the extruder or the intermediate store, and at the outlet openings of the distributor, in order to uncontrollably exit the plastic compound from the openings or during connection and disconnection and when changing the mold To prevent reflux into the extruder. This is especially true in the case that the plastic compound, a blowing agent is added, since the propellant-containing plastic mass continuously expands and Without shutters out of the openings out of control uncontrolled or would flow back into the extruder. The closures can be designed, in particular, as slides which can be actuated by means of hydraulic or pneumatic cylinders. Alternatively or in addition to the closure at the exit of the extruder can be provided that the extruder, even if no material is conveyed into the buffer while it is being emptied, continues to run at low speed to generate the necessary back pressure and thereby a backflow into to prevent the extruder.

The Casting station may further comprise means for coupling the mold the outlet openings of the distributor or for holding the Have shape during the filling process. In particular, can the casting station have means for centering the mold, so that these are exactly with the fill holes of the Mold pressed against the outlet openings of the distributor becomes. The guide elements can, for example as appropriately beveled guide rails or sheet metal profiles may be formed, wherein the mold in the for the centering necessary measure by putting on one movable storage, for example, movable on a ball table can stay.

Of the Casting station may further include a controllable handling device, For example, an industrial robot, be assigned to the shape for coupling and uncoupling and for attaching to the outlet openings to move the distributor accordingly.

In Transport direction of the transport device is after the casting station arranged a cooling area. This particular can an upwardly open, as an elongated container trained water basin or a gutter, the or which is arranged below the running rail. The water basin or the gully is in particular designed such that the forms completely or at least partially into the water basin or the gutter absorbed cooling water can. As a result, the shape and thus the contained therein Plastic mass cooled down as far as possible after the casting process, that the plastic mass solidifies and the transport pallet formed therefrom can be removed in the demoulding station. Instead of water can also depending on the temperature range and desired cooling rate another coolant or a mixture of water with be used a different coolant.

To the Dipping the molds in the pool or gully can the trolleys be designed so that the shapes accordingly can be lowered. Alternatively or in addition This can also be the running rail in the cooling area a have corresponding depression to the forms in the cooling water immerse. The shapes will be for a period of time immersed in the coolant, given or due one of the cooling area, the trolley or the form associated Sensors supplied temperature signal can be determined.

According to one particular embodiment of the invention is an active Cooling of the cooling water provided. Therefor the cooling water can be absorbed in particular in a gully that is flowed through by cooling water that over a cooling circuit through a heat exchanger or cooler is performed. The cooler can in particular for the delivery of heat to the outside air or be formed on another heat reservoir, wherein the heat also fed to another use can be. The refrigeration cycle further comprises corresponding ones Pumping and control means for generating and controlling the cooling water flow.

Of the Cooling area is designed such that the forms for a sufficiently long time of cooling by immersion can be exposed to the pool or gully, so that the plastic mass contained in the molds solidifies. Therefor It can be provided that the forms of the trolleys through the water will be moved. Because of the trolleys one each own drive and can be controlled separately, it may according to another embodiment the invention also be possible, the forms along the Direction of the track to move back and forth. Furthermore, can the shapes also being pivotally mounted on the trolleys, that with a less viscous plastic melt accumulate prevents the bubbles generated by the blowing agent in the upper region of the mold can be; this can for example be provided for be, several lifting means, about which a form to a trolley is attached, move differently, so that the Form is rotated about a horizontal axis.

there is the cooling area in a preferred manner designed such that several forms simultaneously in the pool or pools be immersed and thereby cooled. It can also be several pools or gullies, possibly with several cooling circuits, provided be, which can also have different temperatures. Overall, for example, a total immersion time of approx. Be provided 30 min. In addition, another, pre, intermediate or subsequent cooling time at the Be provided air.

In the demolding station, for example, near or close to the casting station ing end of the oval transport path is arranged, the largely cooled pallets are removed. The demolding station comprises a receptacle adapted to the casting mold, which is formed by a frame, in particular a steel frame. In the receptacle, a mold can be used, for example by being lowered by the lifting means of the trolley from above.

The Recording comprises according to a preferred embodiment the invention two wedge-shaped in the upper area Abutment on which the mold is placed with its lower edge becomes. The recording or the frame can be slightly inclined be inclined at the back, so that the mold is used safely and can not tip over. To fix the shape in the upper area can barbs may be provided for example. The shape is in the picture This makes it sufficiently accurate for those in the demoulding station necessary handling positioned.

to Removal of casting cores may be used by the demoulding station. in particular one or more industrial robots, be assigned. The mold can also be designed such that it by the robot or can be opened. After opening any locking means of a lid of the mold becomes the lid still synonymous due to the inclination of the recording and by any Retaining strips held; the lid is made according to this Embodiment therefore active by the handling means taken off, so that the transport pallet formed from the solidified plastic material can be removed. After removal of the pallet, the lid put back on, the bolt closed and possibly the casting cores again inserted from both sides.

To Resealing the mold can be transported further become. Between demoulding station and casting station is in the transport direction of the transport device according to a preferred embodiment of the invention, a buffer area arranged. In this area can be one or more Trolleys with the forms transported by these in a queue linger before it is transported back to the casting station become. This may possibly different processing, Cooling and / or transport times are compensated. In particular, this makes it possible to have a larger one Number of trolleys and molds in an inventive Arrangement to provide, as in a rapid passage through casting station, Cooling area and demoulding station would be required; in the case that the passage is through the cooling area, for example is slowed down, but still no at the casting station Downtime should occur, the material quality and / or productivity would be compromised then enough trolleys and molds available to to continue the manufacturing process continuously. As well Both the trolleys and the empty molds can stand at a standstill the system are stored in the buffer area.

The Molds are according to a preferred Embodiment of the invention as closed aluminum molds formed, which have a cavity in shape and size essentially corresponds to the transport pallet to be produced; Cast cores may also be provided. The aluminum molds each advantageously consist of a cast body and a lid. Lid and castings are over a lock connected to each other. This can in particular be designed such that they are of a handling device, For example, an industrial robot, in easier and safer Can be opened and closed. Likewise is the lid in particular designed in such a way and with the cast body connected to the cover of a handling device in easier and safely removed and put back on. Between cast body and lid can seals be provided to a swelling of the plastic material, in particular if this is foamed, prevent it.

The Shapes preferably have a plurality of filling openings depending on the shape and size the transport pallet to be produced, in a conventional manner are arranged so that as uniform as possible and complete filling of the mold in the desired Time can be achieved. Each filling opening points while a closure, which in a preferred manner by a continuous strip for a plurality of openings is realized (hereinafter referred to as "sword lock"). As a result, leakage of the plastic material or an outsource prevents, even if the plastic mass due to an added Propellant even after filling in the mold still nachquillt. For example, one shape may be two each horizontally arranged Bars have trained sword closures, respectively one for a plurality of in an upper filling bar arranged filling openings and a for a lower filling bar.

The sword closures are preferably designed such that they are closed following the casting process via actuators located at the casting station and can be opened by actuators or handling means following the removal of the transport pallet at the demoulding station. The Schwertverschlussriegel can be made of PTFE (Teflon ^® ) or coated with it, so that despite the in the Form located sticky plastic mass sufficient slip properties are ensured, while the required temperature resistance is given.

to Control of the operation of the arrangement according to the invention or plant for the production of transport pallets may further a Control device may be provided, the particular sensor means for the acquisition of process data and processor means for processing the data collected by the sensor means and the control of the Plant includes.

Especially Sensor means may be provided to achieve and / or Leaving a predetermined position before, in and / or after the casting station and / or the demoulding station by a trolley or with a to detect this connected form. For this purpose can For example, light barriers, distance sensors, capacitive proximity sensors or touch sensors are used. The control device For example, due to reaching a position in front of the Casting or demoulding the trolley in question to control the transport speed and / or a provision of holding means, such as by opening or pulling back barbs. by virtue of reaching a position in the casting or demolding station can corresponding actuators or handling means for holding, opening and / or filling the mold be controlled. Reaching a position after the casting or demoulding station can be used as an enable signal for the Transport the next form to the relevant station be used.

The Sensor means may be further adapted to process parameters, such as the temperature of the plastic mass in the extruder, in the buffer, in the distributor and / or in the form during filling and / or the temperature of the mold or of the plastic mass contained in the mold before, during and / or after passing through the cooling zone capture. The control device can in the event of deviations from Setpoints Corrective actions, for example, through changes the heating power and / or the filling speed or the speed of the trolleys and / or the residence time in the cooling zone, cause. Furthermore, the sensor means also for detection serve of error conditions. Accordingly, when achieved a limit, for example, an emergency stop be prompted, such as by a pressure sensor, which reduces the pressure when filling the Measures forms.

The Processor means may be different processors, in particular Microprocessors or computers include, for example, the Casting and / or the demoulding station or trolleys assigned. Furthermore, the control device in an advantageous Way of communicating with the equipment assigned to or from the plant comprised handling means or industrial robots trained and for this the corresponding interfaces in hard- and software.

The Control means may further input and display means for entering control data, for programming the control and to display process parameters. After all the controller may be wired and / or wireless transmission means for transmitting the sensor data and / or control commands exhibit. In this case, advantageously, a computer bus protocol, For example, a CAN bus to be used.

The Inventive arrangement for the production of Transport pallets of plastic, in particular of recycled plastic, is further designed so that at least one substantially closed mold is coupled to a casting station. For this purpose, the mold is inserted into a holder and open the filling openings of the mold; the filling openings can also beforehand have been opened. The filling openings are attached to the outlet openings of a distributor, for example, by making the form automated by a preferred controlled handling device to the outlet openings of the distributor is pressed.

In The casting station is liquefied in an extruder a creamy Produced plastic compound, in particular from granules of recycled plastic, fed to the extruder from a reservoir becomes. The pasty plastic mass is according to a preferred embodiment in a cache under Retention of the corresponding temperature cached, if necessary with the addition of propellant. After a dwell in the cache, in particular of the delivery rate of pasty Plastic mass depends on the extruder, which is in the Latch stored generated plastic mass to the distributor delivered and pressed into the mold.

According to a preferred embodiment of the invention, the amount of plastic material stored in the buffer and delivered to the manifold corresponds to that which is necessary to substantially completely fill the mold. In this way, a particularly simple and accurate dosage is possible. In particular, it is usually no longer necessary to monitor the level or pressure of the filled plastic in the mold to determine when the casting process is completed. If a propellant supplied has been given, the volume of the output from the buffer plastic mass must not be equal to the volume of the cavity to be filled mold. Since the plastic mass containing the blowing agent also continues to swell during the filling process, the plastic mass can also fill a cavity that is larger than the volume that the plastic mass had when leaving the intermediate store. Due to the reproducibility of the process, however, the volume of the buffer can be selected such that the shape is optimally filled by dispensing the contents of the buffer despite the further expansion of the plastic material.

Of the Filling process can in particular by at the output of the Unit of extruder and buffer or to the individual Docking openings of the distributor arranged, preferably automatically actuated slide controlled who the. This can also a swelling of the expanding propellant-containing plastic mass be avoided from the openings.

in the The filling openings are connected to the casting process the shape of located on the casting station actuators closed. These actuators are preferably automatically actuated. Thereafter, the pressing force is released by the handling device, the shape also has some of the output openings the casting station can be moved away.

The Shape is then automatically by a transport device through drove a cooling zone. For this includes the Transport device, in particular at least one trolley, the is automatically controllable and attached to the mold. Especially the shape is attached to the trolley so that the shape when Reaching a position above one in the cooling area located, with cooling liquid, in particular Water filled container or one with water filled gutter automatically lowered and thereby into the Coolant is immersed, so that the Cooling is accelerated. The shape is for this purpose some time, for example, for about 30 minutes, in the coolant dipped, the mold to enhance the cooling effect can be moved in the cooling liquid or the Coolant is moved.

To some time, especially after the mold has cooled so far is that the plastic material has solidified and removed the transport pallet can be, the mold is from the cooling liquid lifted out and through the trolley to a demolition station transported.

In The demolding station is used in a holder form and kept there. By a preferably automated handling device, in particular one or more industrial robots, the shape becomes unlocked and opened and the largely cooled Removed transport pallet. The transport pallet is from the handling device for example, on a roller conveyor with a slope placed at the other end, if necessary by means of a robot stacked or manually removed. A manual post-processing the transport pallets is due to the improved reproducibility in the inventive arrangement usually not necessary anymore. In the demoulding station, the shape is restored closed, in addition, the closure of the filling openings to be opened again.

The empty forms then wander over another part of the Transport route back to the casting station. In a preferred embodiment, a buffer area is provided, where the Forms at standstill of the plant or to compensate for different Processing times, for example, depending on the composition of the plastic material or when starting the Plant, can be stored.

The The invention will be more closely understood by way of example with reference to the drawings explained. They show, in each case as a schematic diagram:

1 an embodiment of an inventive arrangement, seen from above;

2 a partial perspective view of the transport from 1 ;

3 a mold attached to a trolley;

4 a closure of the filling openings of a mold;

5 a part of the casting station 1 as a detail;

6 a detail of the casting station in perspective view;

7 another detail of the casting station in perspective view, and

8th the receiving device of the demoulding station 1 in side view.

According to 1 For example, an arrangement or installation for the automated production of transport pallets comprises a transport device 1 that with a circumferential track 1.1 for guiding a plurality of trolleys 1.2 is trained. The running rail is arranged approximately in the form of an oval and leads through a casting station 2 , a cooling area 3 and a demoulding station 4 , The demoulding station is a roller conveyor 5 allocated for transporting the finished transport pallets. Part of the moving distance of the trolleys forms a buffer area 6 in which trolleys with empty forms, a queue for the supply to the casting station 2 can form.

Every trolley 1.2 has its own drive for propulsion along the rail. A self-propelled trolley 1.2 is over one beside the track rail 1.1 arranged busbar and a pantograph (not shown) supplied with the required for the operation of the trolley electrical energy. The busbar also serves to transmit control signals from a control device (not shown) to the trolley 1.2 ,

As in 2 shown, the running rail 1.1 by supports 1.3 be raised. At the track 1.1 hang the trolleys 1.2 and engage with their respective drive in the track 1.1 one. A form 7 into which the plastic material for the production of the transport pallets is poured, is from the trolley 1.2 on chains 1.4 carried. Every chain 1.4 has a hook 1.5 on, in the form 7 with an eyelet 7.1 is mounted. The pair of chains 1.3 by means of which the form 7 is suspended, can be lowered or raised separately for each trolley motor. The hooks 1.5 may also have pulleys over which the chains 1.3 are guided in the manner of a pulley (not shown). If the hooks 1.5 are provided with pulleys, can also be a single chain on the pulleys of both hooks 1.5 to run; This has the advantage that a single drive is sufficient to both hooks 1.5 raise or lower. But it can also be provided, the two chains 1.4 to steer differently to the attached form 7 to pivot about a horizontal axis.

The trolleys 1.2 may further comprise displacement measuring devices and sensors or limit switches (not shown), which serve to increase the accuracy of the control. Furthermore, this can prevent collisions with preceding or following trolleys or an emergency shutdown can be triggered in the event of a collision. The trolleys 1.2 can also use temperature sensors to detect the temperature of an attached form 7 exhibit. Furthermore, the trolleys signaling means, such as warning lights or operation control lamps, have, as well as controls and possibly an emergency stop button (not shown). These measures make it easier to set up and commission the system and to increase safety when setting up and operating the system.

The casting molds used to make the transport pallets 7 are formed according to the shape and size of the pallets approximately in the form of a rectangular plate. The molds are preferably made of aluminum and each consist of a lid 7.2 and a cast body 7.3 , as in 3 from the direction of the lid 7.2 seen is shown. cover 7.2 and castings 7.3 are about bars 7.4 laterally into holes in plates connected to the cast body 7.5 grab, connect with each other. This allows a secure closure of the mold 7 , even under the possibly resulting from the swelling of the plastic mass pressure can be achieved. The bars 7.4 are by clips attached to the lid 7.6 guided. The bars 7.4 have a rectangular cross-section, the outer ends 7.7 are rounded. The bars 7.4 are arranged in pairs, with two bars each in the lower area and in the upper area of the lid 7.2 are provided so that engagement of the bolt 7.3 in the plates 7.5 takes place approximately at the four corners of the plate-shaped form. The inner ends of the bars of each pair are in the region of an actuating plate 7.8 arranged, which is a handle 7.9 having. By turning the actuator plate 7.8 can the bars 7.4 a pair of both outwards, ie, for locking, or inward, ie, for unlocking, to be moved. The lid 7.2 itself also has a handle 7.10 , which may be a bolted rail, for example, on. Further, on the lid 7.2 retaining strips 7.11 appropriate.

The Shape can reduce the adhesion of the manufactured pallet be coated on the inside with an adhesion-reducing material, or it may be such in the course of the described automatic Be sprayed manufacturing process, preferably after Removal of the mold in the demoulding station. The shape can also be one or more temperature sensors included.

Form 7 may also include removable cores, each of which is provided with a handle, such as a bolted rail (not shown). Corresponding to the design of the cavity formed by the mold filling openings are provided, which are arranged such that an optimal filling is achieved. The filling openings also have a closure to prevent leakage of plastic compound or caused by the further expansion of the mixed with propellant plastic material sour out. The closure can be realized by a continuous bar for each three arranged almost at the same height openings (hereinafter referred to as "sword lock").

Such a sword lock is sche mentally in 4 shown. The filling openings 7.12 the form 7 become from one at the casting body 7.3 arranged strip 7.13 educated. In or at the bar 7.13 is a slider 7.14 movably mounted, which is designed as a longitudinally displaceable bar, which the filling openings 7.12 has corresponding holes. By pressing the slider 7.14 in the direction of the double arrow can thus all filling openings 7.12 the bar 7.13 be opened or closed at the same time. The slider 7.14 may comprise a handle or a means of engagement, such as an eyelet, (not shown) to enable automatic actuation in both directions of the double arrow, for example by a robot, a pneumatic cylinder or other handling means equipped with corresponding engaging means. In order to achieve good sliding properties and to prevent sticking by solidified plastic compound, consist of the slide 7.14 and possibly also the bar 7.13 of an adhesion-reducing material, for example PTFE ( ^Teflon® ) or are coated with such a material. PTFE also has the required temperature resistance. In order to prevent leakage or protrusion of the plastic mass even under the pressure generated during re-swelling, the sword locks are formed as tight as possible; also the connection between castings 7.3 and lid 7.2 as well as other openings, such as for insertion of the cores, are correspondingly dense and may optionally have seals.

The casting station 2 includes, as in 1 and 5 is shown schematically, an extruder 2.1 , a cache 2.2 and a distributor 2.3 ,

The extruder 2.1 serves to provide the plastic used for the production of the transport pallets in a suitable for the casting consistency. This is done in the extruder 2.1 made of a plastic granules a pasty plastic mass. The plastic granules, which consists in particular of recycled plastics, from a reservoir 2.4 sucked in and via a delivery line 2.5 in one above the extruder 2.1 arranged funnels 2.6 directed from where it is the extruder 2.1 is fed (s. 1 ). According to the described embodiment of the invention preferably no fiber additive is used.

The extruder 2.1 is powered by an electric motor 2.7 driven and in particular comprises a screw conveyor, which is driven at a speed of about 200-300 U / min. In order to liquefy the plastic mass creamy, without this being chemically disadvantageous, the extruder is heated by a heater, not shown, and maintained by a temperature control in a predetermined temperature range, for example at about 160-180 ° C.

To the extruder 2.1 is over a short piece of pipe 2.8 a cache 2.2 connected, which is also referred to as "battery head". The buffer has a variable volume, as in 5 by the via a piston rod or by another electric motor 2.9 driven spindle 2.10 reciprocable piston 2.11 is indicated. The cache 2.2 In this case, it is configured in such a way that the plastic material first conveyed into the intermediate store also leaves it first (FIFO function). The cache 2.2 is over a pipe 2.12 with the distributor 2.3 connected, which is a branch into a plurality of tubular conduits 2.13 has, in each case in docking openings 2.14 end, which may be formed as tubular filler neck. The pipe 2.12 and the wires 2.13 are provided with heating elements (not shown) to keep the plastic mass here at the required temperature (about 160 ° C).

The docking openings 2.14 are arranged so that they on corresponding filling openings of a set for filling (docked) form 7 fit. In particular, the docking openings 2.14 be arranged for example in two horizontal bars to three openings. Such a bar 2.21 with three docking openings 2.14 is in 6 represented, wherein the flow direction of the pasty plastic material is characterized when filling the form with arrows. Below the bar 2.21 is an investment plate 2.23 to improve the positioning of the mold 7 when docking arranged. The docking openings 2.14 the bar 2.21 can be opened or closed together by a slider. According to 6 are the docking openings 2.14 as tubular filler neck 2.24 educated.

The slider 2.15 at the output of the arrangement of extruder and intermediate storage is preferably actuated hydraulically. The sliders 2.16 at the individual docking openings 2.14 The upper and lower strips also each have a hydraulic or pneumatic cylinder, not shown. But it can also be several docking ports 2.14 a bar through a slider 2.16 be operated, for example, in the form of a sliding bar, the distance of the docking ports 2.14 Has openings, may be formed. By closing the slide or the slide 2.16 can be prevented that the propellant-containing plastic mass due to the continuous expansion from the docking ports 2.14 spills out uncontrollably. The slider 2.15 serves to prevent backflow from the distributor into the buffer 2.2 ,

That the extruder 2.1 supplied plastic granules are liquefied creamy from the extruder and as a pasty plastic mass over the pipe section 2.8 in the cache 2.2 promoted and cached there while maintaining the appropriate temperature, as in the DE 10 2007 051 939 A1 described. The piston 2.11 For this purpose, it is moved from a starting position to an end position to the volume of the buffer necessary for the storage 2.2 to provide. During this process, the pneumatically operated slide 2.15 be closed, as well as the slide 2.16 at the docking openings 2.14 , so that at this time an already filled form 7 undocked and a new empty form 7 can be docked.

Is a new form 7 docked and the cache filled with a predetermined amount of liquefied plastic mass, so are the slide 2.15 and 2.16 as well as the sword closure and the sword locks of the form 7 opened and the plastic mass from the buffer through the pipe 2.12 and the wires 2.13 of the distributor 2.3 promoted into the mold. For this purpose, only a relatively low pressure of about 50 bar, preferably less than 30 bar is required. Possibly. this can be another slider 2.17 closed and the extruder stopped. But it is also possible, the screw conveyor of the extruder 2.1 with a low number of revolutions, for example at 2-3 rev / min, continue to run; This is advantageous to ensure a uniform texture and consistency of the plastic material.

The cache 2.2 thus makes it possible, by movement of the piston 2.11 from the end to its starting position a defined amount of plastic mass in the mold 7 so that it is just completely filled, without any manual monitoring or monitoring by sensors to determine the filling state of the mold 7 necessary is. To increase the safety, however, a pressure sensor may be provided which, for example, in the case of an impermissible increase in pressure in the distributor 2.3 or in the pipe 2.12 triggers an alarm or an emergency stop.

The extruder 2.1 is equipped with a further connection for the supply of propellant (not shown). The propellant has the property to produce gas bubbles at the temperatures prevailing in the plastic mass, which give the finished transport pallet a hard foam-like structure and thus serve the material savings and weight reduction. For storing and supplying the propellant, for example, one on the extruder 2.1 arranged funnel be provided (not shown). Instead of in the extruder 2.1 The blowing agent can also be in the pipe section 2.8 , in the cache 2.2 or in the pipe 2.12 be added.

For docking a form 7 This is from a trolley 1.2 in a holding device 2.18 the casting station 2 lowered. The holding device is in 7 shown in perspective view. The holding device 2.18 has a carrier 2.20 on top of the wires 2.13 of the distributor carries and through this to a bar 2.21 passed through. The bar 2.21 has the docking openings 2.14 on, to which a form 7 can be docked. The docking openings 2.14 the bar 2.21 can through the slider 2.16 open or close together. The direction of movement of the slider 2.16 is in 7 characterized by a double arrow, the flow direction of the plastic mass when filling the mold 7 by a simple arrow. For easier positioning of the mold 7 are a sliding storage on a ball table 2.22 provided as well as a bearing plate 2.23 ,

When docking first sets the lower end or edge of the form on the ball table 2.22 on. Form 7 is then from a handling device, such as a suitably programmed industrial robot 2.19 or also a pneumatic or hydraulic pressure cylinder, against the docking openings 2.14 pressed. The mold is thereby centered by guide elements, for example oblique guide rails on both sides of the mold in the region of the ball table, in such a way that the filling openings of the mold and the docking openings of the casting station come to lie one above the other. In order to keep the form in an approximately vertical position, the shape 7 also be lowered in the way that the chains 1.4 the trolley 1.2 continue to be under some tension. Instead or in addition, the shape 7 be held by the handling device in a corresponding position; this can be the form 7 even have appropriate handles. This makes it possible, both in the lower and in the upper region of the mold 7 arranged filling openings in exact accordance with the docking openings 2.14 in a lower and an upper bar 2.21 can be arranged to bring.

To ensure a consistently accurate positioning of the mold 7 and a dense connection between distributors 2.3 and shape 7 to achieve a holding force can be exerted by the handling device during the casting process; but it is also possible that this holding means are provided, for example, hooks that hold the mold in a suitable position or act on a corresponding force. For filling the mold 7 be both the slider 2.16 at the docking openings 2.14 as well as the sword locks of the form 7 actuated. For this purpose, the casting station Ak tuatoren, in particular hydraulic or pneumatic cylinders, which are actuated by the controller according to the procedure described.

Is the amount of plastic mass contained in the buffer over the pipe 2.12 have been emptied, so are the slides 2.15 and 2.16 closed, if necessary, the slide 2.17 opened, the extruder 2.1 is regulated to the speed necessary to convey the plastic mass, and the buffer 2.2 filled again.

Likewise, after the casting process, the sword locks of the form 7 through at the casting station 2 located actuators and thereby the filling openings 7.12 the form 7 closed. Form 7 is moved by the handling device from the docking ports 2.14 solved (undocked) and from the trolley 1.2 raised again.

After casting, the molds run 7 over a gully 3.1 (S. 1 ) and are from the trolleys 1.2 in this abge lowered into the cooling water contained therein, so that the cooling is accelerated. The forms 7 remain over a sufficient time for the curing of the plastic, for example, about 30 min, in the gutter 3.1 , The cooling water can be additionally cooled; this is a cooling circuit 3.2 provided, the coolant lines 3.3 optionally pumping and control means (not shown) and a cooler or heat exchanger 3.4 for delivering the heat to the air or to another heat reservoir. As in 1 Obviously, several shapes can enter the gutter simultaneously 3.1 be immersed. The gully may have a length sufficient for continuous forward movement of the molds, for example about 25 m. Because the trolleys 1.2 can be controlled independently, can also be a reciprocating motion of several forms 7 be controlled collision-free. When the forms 7 or the transport pallets have cooled sufficiently or after a predetermined residence time, the forms 7 from the trolleys 1.2 lifted out again and the demolition station 4 at the opposite end of the casting station front end of the oval transport path of the transport device 1 transported.

The demoulding station 4 includes according to 8th a steel frame 4.1 , which has a holder adapted to the aluminum mold 4.2 with a recording 4.3 contains. To insert into the receptacle 4.3 becomes the shape 7 from the trolley 1.2 lowered so that the lower edge of the mold 7 in the recording 4.3 touches where it is centered and held by wedge-shaped pins or abutment (not shown) in the upper area. The holder 4.2 is slightly tilted backwards so that the shape 7 can not tilt forward. Form 7 is then fixed in the upper area, by barbs 4.4 around the top edge or through a free space in the cast body 7.3 the form 7 grab and then be lowered, as in 8th through the double arrow 4.5 is indicated. A collision-free insertion of the mold 7 can by a movement of the barbs 4.4 perpendicular to the surface of the mold 7 be relieved, as indicated by the double arrow 4.6 is indicated. This is the shape 7 in the holder 4.2 firmly fixed.

So that the pallet can be removed, the casting cores (not shown), if present, must first be pulled out of the mold. The casting cores each have a screwed-on profile rail as a handle for a handling device, in particular for an industrial robot 4.7 , on. Because the shape in the holder 4.2 A robot can be positioned with sufficient accuracy 4.7 with a gripper 4.8 grasp the cores on the handle and then pull out laterally. To speed up the process, several robots can be used 4.7 be used. The cores are transferred from the robot arms to a clipboard 4.9 placed so that they can be re-inserted after removing the pallet.

Subsequently, the lid 7.2 the form 7 decreased. For this purpose, a first of the two industrial robots opens 4.7 First, the locking of the lid. This locking can be done via a handle 7.9 on the rotatable actuator plate 7.8 to solve. By a rotation of the actuator plate 7.8 for example, by 90 °, by the industrial robot 4.7 with the aid of the gripper rotatable about a longitudinal axis of the robot arm 4.8 is executed, thereby the lid is unlocked. The lid is still through the retaining bar 7.11 in the holder 4.2 held, but can be pulled off to the front. In 8th is the turning of the actuator plate 7.8 through a curved double arrow 4.10 indicated. At the in 8th illustrated variant, the lid 7.2 the form 7 just a pair of bars 7.4 on, with the actuator plate 7.8 in the middle of the lid 7.2 the form 7 is arranged; In this case, the handle can 7.9 on the actuator plate 7.8 also for removing the lid 7.2 from the cast body 7.3 serve. After opening the latch 7.4 the lid engages the first robot 4.7 about the handle 7.9 or via the central handle 7.10 , which is also designed as a profile rail, the lid 7.2 and pulls it off.

The pallet is made by pressing four pestles 4.11 from the cast body 7.3 the form 7 ejected, for which the plunger individually, for example by pneumatic cylinders, or together by shifting a common carrier 4.12 in the direction of the double arrows 4.13 can be moved. The second of the two robots 4.7 that changes Tool required to remove the cores into a tool that can grip the pallets. With this, the robot grabs the pallet, which is then brought to the horizontal and onto a roller conveyor 5 is dropped and released. On the roller conveyor 5 For example, the finished pallets are stacked by another robot or removed manually.

The first industrial robot 4.7 holds the lid 7.2 until the pallet is removed and then reinsert the lid and locks the lid. The tool of the second robot arm is changed again and the casting cores again from both sides in the form 7 inserted. In addition, the robot arms open the sword locks of the mold 7 already for the next casting process. Because of the shape 7 in the holder each assumes a reproducible position, the robot can 4.7 For the individual work steps are programmed to fixed positions, creating a simple and safe process.

The mold is then returned to the holding device by swinging and possibly retracting the barbs 4.4 released from the trolley 1.2 lifted and into a buffer area 6 transported. After lingering in a queue the shape becomes 7 then transported back to the casting station to be refilled. In the buffer area 6 If necessary, the empty molds can also be temporarily stored when the system is at a standstill.

1

transport means

1.1

runner

1.2

trolley

1.3

support

1.4

Chain

1.5

hook

2

casting station

2.1

extruder

2.2

cache

2.3

distributor

2.4

reservoir

2.5

delivery line

2.6

funnel

2.7

electric motor

2.8

pipe section

2.9

electric motor

2.10

spindle

2.11

piston

2.12

pipe

2.13

management

2.14

docking port

2.15

pusher

2.16

pusher

2.17

pusher

2.18

holder

2.19

industrial robots

2.20

carrier

2.21

strip

2.22

ball table

2.23

bearing plate

2.24

filler pipe

3

cooling section

3.1

gully

3.2

Cooling circuit

3.3

Coolant line

3.4

heat exchangers

4

casting release

4.1

steel frame

4.2

bracket

4.3

admission

4.4

barb

4.5

double arrow

4.6

double arrow

4.7

industrial robots

4.8

grab

4.9

clipboard

4.10

double arrow

4.11

tappet

4.12

carrier

4.13

double arrow

5

roll band

6

buffer area

7

shape

7.1

eyelet

7.2

cover

7.3

cast body

7.4

bars

7.5

plate

7.6

hanger

7.7

appearance The End

7.8

operating plate

7.9

handle

7.10

handle

7.11

retaining strip

7.12

fill opening

7.13

strip

7.14

pusher

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19821397 A1 [0002]
• - EP 2058104 A2 [0003, 0014, 0015]
• - DE 102007051939 A1 [0069]

Claims (20)

Arrangement for the production of transport pallets of plastic, in particular of recycled plastics, comprising at least one casting station ( 2 ) for filling at least one closed mold ( 7 ) with plastic, wherein the casting station an extruder ( 2.1 ) for providing creamy liquefied plastic material and a distributor ( 2.3 ) with at least one docking opening ( 2.14 ) for introducing the plastic material into a mold ( 7 ), further comprising at least one cooling zone ( 3 ) for cooling the mold to the solidification of the plastic material and a demolding station ( 4 ) for opening the mold, removing the transport pallet formed from the plastic material and reclosing the mold, characterized in that the arrangement further comprises a transport device ( 1 ) for the automated transport of the at least one mold ( 7 ) from the casting station ( 2 ) through the cooling zone ( 3 ) to the demoulding station ( 4 ) and back to the casting station ( 2 ). Arrangement according to claim 1, characterized that the arrangement for automated production is formed by transport pallets. Arrangement according to one of the preceding claims, characterized in that the arrangement between a demolding station ( 4 ) and casting station ( 2 ) buffer area ( 6 ). Arrangement according to one of the preceding claims, characterized in that the arrangement is a control device comprises, the sensor means for detecting process data and processor means for controlling the arrangement. Arrangement according to one of the preceding claims, characterized in that the transport device ( 1 ) a circumferential track ( 1.1 ), on which at least one trolley ( 1.2 ) for the transport of the at least one form ( 7 ) is arranged, as well as a parallel to the running rail ( 1.1 ) extending busbar for supplying the trolley with electrical energy and for transmitting control signals, wherein the trolley has an electric drive motor for driving the movement of the trolley, and holding means for holding at least one mold and lifting means for raising and lowering the at least one mold. Arrangement according to one of the preceding claims, characterized in that the cooling region ( 3 ) an upwardly open coolant-filled container or a coolant-filled channel ( 3.1 ), into or into which the at least one shape ( 7 ) can be immersed for cooling at least partially. Arrangement according to the preceding claim, characterized in that the container or the channel ( 3.1 ) Is part of a coolant circuit, which further comprises pump means for generating a coolant flow and a heat exchanger ( 3.4 ) for discharging the heat entrained by the cooling liquid to an external reservoir. Arrangement according to one of the preceding claims, characterized in that the filling of the at least one mold ( 7 ) at a low pressure, in particular at a pressure of not more than 50 bar, preferably at a pressure of not more than 30 bar, and in that the casting station ( 2 ) continue to store a buffer ( 2.2 ) for receiving and controlled discharge of the extruder ( 2.1 ) provided plastic material to the distributor ( 2.3 ). Arrangement according to the preceding claim, characterized in that the temporary storage ( 2.2 ) is formed such that a filling of the buffer ( 2.2 ) a filling of the at least one mold ( 2.3 ) corresponds. Arrangement according to one of the preceding claims, characterized in that the casting station ( 2 ) is further adapted for the supply of a blowing agent in the plastic material to obtain a foam-like structure of the transport pallet. Arrangement according to one of the preceding claims, characterized in that the demoulding station ( 4 ) a holder ( 4.2 ), in which an inserted casting mold ( 7 ) is held in a tilted position against the vertical. Arrangement according to the preceding claim, characterized in that in the demoulding station ( 4 ) opening the mold ( 7 ), the removal of the transport pallet formed from the plastic material and resealing occur automatically. Arrangement according to one of the preceding claims, characterized in that it is designed in this way, - at least one substantially closed form ( 7 ) to the casting station ( 2 ), - fill the mold with a pasty plastic material under a relatively low pressure, - close the mold and decouple the mold from the casting station, - mold through the cooling zone ( 3 ) for solidifying the plastic material, - open the mold and the transport pallet formed from the solidified plastic material in the demoulding station ( 4 ), - to close the mold, and - to transport the mold back to the casting station for renewed coupling to the casting station, the assembly being designed for automated transport of the at least one mold. Casting mold ( 7 ) for use in an assembly according to any one of the preceding claims, wherein the casting mold ( 7 ) a plurality of filling openings ( 7.12 ), which along at least one fixed bar ( 7.13 ) and wherein the arranged along a bar filling openings can be opened and closed by a common closure, characterized in that the common closure is formed as a longitudinally displaceable relative to the fixed bar bar, which has holes corresponding to the filling openings. Casting mold according to the preceding claim, characterized in that the fixed and / or the displaceable Strip made of an adhesion-reducing material, in particular of PTFE, exist or are coated with it. Casting mold according to claim 14 or 15, characterized in that the casting mold consists of a cast body ( 7.3 ) and a lid ( 7.2 ) and the lid with the cast body via a plurality of arranged on the cover bars ( 7.4 ) is tightly connected. Casting mold according to the preceding claim, characterized in that the bolts ( 7.4 ) in pairs by rotation of an actuating plate ( 7.8 ) are displaceable in opposite directions. Casting mold according to the preceding claim, characterized in that the actuating plate ( 7.8 ) a handle ( 7.9 ) for automatic operation by an industrial robot. Casting mold according to one of claims 16 to 18, characterized in that the lid ( 7.2 ) a handle ( 7.10 ) for handling by an industrial robot. Casting mold according to one of the claims 14 to 19, characterized in that the casting mold a or a plurality of removable casting cores, respectively have a handle for handling by an industrial robot.