GB2236517A

GB2236517A - Process for automatically feeding machines with packaged materials

Info

Publication number: GB2236517A
Application number: GB9018800A
Authority: GB
Inventors: Ernst Sauerbruch; Christian Braun; Erich Lehmann
Original assignee: Fahr Bucher GmbH
Current assignee: Fahr Bucher GmbH
Priority date: 1989-08-31
Filing date: 1990-08-29
Publication date: 1991-04-10
Also published as: GB9018800D0; FR2651172A1

Abstract

A process for automatically feeding a machine, such as an injection moulding machine, with a pasty material packaged in an airtight manner in a packaging film so as to form a bag comprises the steps of detaching the packaging film from the pasty material, for instance by injecting air between the material and the film, severing the film, removing the film and feeding the pasty material to the machine. Various ways of carrying out these steps and suitable apparatus are described. Instead of air injection means 8 to detach the film from the surface of the pasty material, suction caps or a vacuum chamber may be used. The film, once severed by pivoted or fixed cutters 17, may be removed by grippers 32 (Figs. 5 and 6) or other strippers. <IMAGE>

Description

Title: PROCESS FOR AUTOMTICALLY FEEDING MACHINES WITH PACKAGED MATERIALS This invention relates to a process and a device for automatically feeding machines with packaged materials, in particular for feeding polyester materials for processing in injection moulding machines, the polyester material being a pasty material packaged in airtight manner in a packaging film as a convenient polyester bag.

The polyester moulding materials used for plastics processing, for instance in injection moulding machines, are supplied in a pasty, sticky state and are fed to a plasticising cylinder of the injection moulding machine.

In order that the polyester moulding material should not be hardened by the action of air or be exposed to the possible risk of contamination, it is divided into convenient portions and packaged airtightly in a flexible plastic film to form a so-called polyester bag.

This also avoids a smell nuisance for the operators and contact with the sticky material. Furthermore, it is possible to store the polyester bags for a fairly long time.

In- order to process the polyester material in the injection moulding machine, the polyester bag must be opened and the packaging film detached from the polyester material. This should take place as shortly as possible before the polyester material is introduced into the feed cylinder. With the known machines and feed installations this work is carried out manually.

It is very difficult and time-consuming for the operators to detach the packaging film, which adheres strongly to the sticky polyester material. This necessitates the application of great force and also involves unpleasant nuisances resulting from smell and contact with the sticky polyester material.

Furthermore, the empty packaging films which are smeared with polyester material are a nuisance in the workplace.

It is an object of the invention to avoid the aforementioned drawbacks and to develop a process for automatically supplying material to an injection moulding machine.

According to the present invention there is provided a process for automatically feeding a machine with a pasty material packaged in an airtight manner in a packaging film so as to form a bag, wherein the bag is fed to a device in which the following process steps are carried out: (A) the packaging film is detached from the sticky material, (B) the packaging film is severed, (C) the packaging film is removed, and (D) the pasty material is fed to the machine.

The advantages achieved with the present process and preferred embodiment thereof consist in that the entire operating procedure of the machine can be improved and accelerated. This increases the productivity and economy of the entire installation.

In order to enable the invention to be more readily understood, reference will now be made to the accompanying drawings, which illustrate diagrammatically and by way of example some embodiments thereof, and in which: Fig. 1 is a side view of a feed apparatus for carrying out the process according to the invention, Fig. 2 is a longitudinal section, to an enlarged scale, through a compressed air injection device of the apparatus shown in Fig. 1, Fig. 3 is a top plan view of the feed apparatus shown in Fig. 1, Fig. 4 is an enlarged front view of a cutting device of the apparatus shown in Fig. 1, Fig. 5 is a section along the line V-V in Fig. 1 showing gripping arms in an inwardly pivoted position, Fig. 6 is a view similar to Fig. 6 showing the gripping arms in an outwardly pivoted position, Fig. 7 is a top plan view of an embodiment of the cutting device with the cutting direction along a polyester bag, Fig. 8 is a front view of another embodiment of the cutting device of Fig. 7 with the cutting direction transverse to the longitudinal axis of the polyester bag, Fig. 9 is a top plan view of yet another embodiment of the cutting device with the cutting direction along the polyester bag, Fig. 10 is a front view of the cutting device of Fig.

9, Fig. 11 is a top plan view of an embodiment of the cutting device with two pivot arms, Fig. 12 shows an embodiment of a cutting blade with a circular cutting disc and a depth limit stop, Fig. 13 shows an embodiment of the cutting blade with a fixed cutting edge and depth limit stop, Fig..14 is a top plan view of an embodiment of the cutting and gripping device, Fig. 15 is a front view of the embodiment shown in Fig. 14, Fig. 16 shows another embodiment of a gripping device for removing a packaging film, Fig. 17 shows another embodiment of the gripping device of Fig. 16, Fig. 18 shows a front view of a feed device for an injection moulding machine, Fig. 19 shows the feed device of Fig. 18 with a tiltable working plane, Fig. 20 shows another embodiment of the feed device of Fig. 18 and Fig. 21 shows a diagram of another embodiment of the course of the process, Fig. 22 is a side view of another embodiment of apparatus for carrying out the process according to the invention, and Fig. 23 is a partial view showing the embodiment of Fig. 22 with a pivoted-out gripper for removing a packaging film.

Referring now to Figs. 1 to 6 of the drawings, there is shown apparatus in which polyester bags 1, which are filled with polyester material 2 to be processed, are supplied on a conveyor belt 3 to a separation device 6 preceding the feed cylinder 4 of the injection moulding machine 5 . In the separation device 6, a packaging film 7, within which the polyester material 2 is packaged in an airtight manner, is separated completely automatically from the sticky polyester material 2 so that the latter can be introduced into the feed cylinder 4 for further processing.

The separation device 6 consists of a compressed air injection device 8 for detaching the packaging film 7 from the sticky polyester material 2 (process step A) and a cutting device 9 for cutting through the detached packaging film 7 (process step B). The packaging film 7 is penetrated with the aid of a hollow needle 10, which is connected to a compressed air source (not shown) via a compressed air duct 11 and a compressed air line 12 (Fig. 2). The tip 13 of the hollow needle 10 is closed and has exit openings 14 directed backwards which are connected to the compressed air duct 11. By injecting compressed air into the polyester bag 1, the film is detached from the polyester material 2 as a result of the pressure difference which is produced between the space inside and the outside of the packaging film 7.

The same effect is achieved if the polyester bag 1 is placed into a low-pressure bell or a low-pressure chamber in which low pressure is generated. Another way of detaching the packaging film 2 consists in placing a plurality of suction arms on the outside of the packaging film 7. The packaging film 7 can be detached from the polyester material 2 by the action of a pulling force on the suction arms.

After the packaging film 7 has been detached by the compressed air injection device 8, the polyester bag 1 is moved towards the cutting device 9 transversely to the direction of conveyance of the conveyor belt 3 with the aid of a feeding plate 15, which is driven by one or more piston/cylinder units 16 or a linear motor. The cutting device 9 consists of two cutting blades 17, which are disc-shaped and are each rotatably mounted on the free end of an upper and lower pivot arm 18. The pivot arms 18 are bent in approximately a U-shape, so that they surround the polyester bag 1 from above and below, with the ends of the pivot arms 18 being brought together at the front and rear ends, the lower pivot arm 18 being passed beneath the conveyor apparatus 3.

Whereas the front ends of the pivot arms 18 bear the cutting blades 17, the rear ends of the pivot arms 18 are mounted on a machine frame 20 so as to be freely rotatable about a common horizontal axis 19 transverse to the cutting direction. The two pivot arms 18 are drawn towards each other with the aid of a spring 21 so that the cutting blades 17 are pressed against the outside of the packaging film 7 and a constant contact pressure on the polyester bag 1 is achieved. In addition, the pivot arms 18 may have a joint in the front region, on which joint the front part of the pivot arm 18 which bears the cutting blades 17 is rotatably mounted and is drawn inward against the packaging film 7 by means of a tension spring.

As a result of the advance movement of the feeding plate 15, the packaging film 7 is cut all around in the radial direction or transverse to the longitudinal axis of the polyester bag 1 by the cutting blades 17, each of which driven by a respective compressed air motor 22. The feeding plate 15 has in the middle a recess 23 for the cutting blades 17 to pass through.

After the packaging film 7 is severed, the polyester bag 1 is moved beyond the cutting device 9 with the aid of the feeding plate 15 and is pushed into a receptacle 24 located in the receiving position of Fig. 1 at the lower end of an inclined hoist 25. The receptacle 24 is associated with two lateral gripping arms 26, which are visible in Figs. 5 and 6, the gripping arms 26 serving to remove the packaging film 7, which has been cut into two pieces, from the polyester material 2 (process step C). For this purpose, the gripping arms 26 are mounted on the machine frame 20 so that each arm is pivotable about a horizontal axis 27 lying in the direction of conveyance of the feeding plate 15, each arm being drivable by an associated piston-cylinder unit 28.A pincer 29 operated by compressed air is arranged on the free end of each gripping arm 26, which pincer is placed on the relevant end of the severed packaging film 7, as illustrated in Fig. 5. In order to remove the packaging film 7, the pincers 29 are closed and the gripping arms 26 are pivoted outward from the position shown in Fig. 5 to that shown in Fig. 6 with the aid of the piston-cylinder units 28 so that the two halves of the packaging film 7 are automatically removed from the polyester material 2. So that the polyester material 2 is not drawn with them, a holding-down device 30 is provided which is placed in the middle of the polyester material 2 and restrains it during the removal operation with the aid of a compressed air piston 31.

The packaging film 7 is stripped off the open pincers 29 with the aid of a sprung stripper 32 which is associated with each pincer 29, so that the film can fall into waste bins which are provided. Then the freed polyester material 2 in the receptacle 24 is moved in front of the filling opening of the feed cylinder 4 with the aid of the inclined hoist 25 and is pushed into the feed cylinder 4 of the injection moulding machine 5 via a plunger (not shown) (process step D). The inclined hoist 25 may be dispensed with if the receptacle 24 succeeding the separation device 6 is arranged directly in front of the filling opening of the feed cylinder 4.

The embodiment described may be modified by different variants of design without departing from the inventive concept of the present application. For instance, instead of the horizontal conveyor belt 3 of Fig. 3 a vertical conveyor belt (paternoster) may also be used for supplying the polyester bags 1 to the separation device 6. It is also possible to insert the polyester bags 1 into the separation device 6 manually.

The cutting device for cutting through the packaging film 7 can likewise be modified by various possible designs. The cutting blades 17 which are designed as rotatable, sharp discs (Fig. 1) or fixed cutting edges (Fig. 7 and 8) may be placed on the polyester bag 1 in such a manner that a section transverse to the longitudinal direction of the polyester bag 1 is produced (Fig. 1, Fig. 8). However, the cutting direction may also run in the longitudinal direction of the polyester bag 1 (Fig. 7, Fig. 9, Fig. 10).

In the embodiment of Figs. 9 and 10, the cutting blade 17 is rotatably mounted on the free end of an arm 33.

The arm 33 is pivoted about a vertical axis 35 on a fixed, vertical bracket 34. For cutting through the packaging film 7 in the horizontal plane and in the longitudinal direction of the polyester bag 1, the arm 33 is driven by a rotational force (arrow 36) or a translatory force (arrow 37) and is moved relative to the polyester bag 1 together with the cutting blade 17.

However, the cutting operation may also be carried out by moving the polyester bag 1 relative to the fixed cutting blade 17. In particular, the polyester bag 1 may be raised so that the packaging film 7 can be cut freely on its underside. In both cases, the polyester bag 1 may lie or stand on the conveyor belt 3, so that the cutting direction is in the longitudinal direction or in the transverse direction of the polyester bag 1.

In particular, the polyester bag 1 may be cut in different shapes, for instance in the upper, lower, front, middle or rear part, in order to facilitate removal of the bag. The cutting blade 17 may be driven by the motor 22.

As Fig. 11 shows, a pivotable arm 33 having a cutting blade 17 may be arranged on each side of the polyester bag 1, so that a cut is made on each side of the polyester bag 1 in the longitudinal direction (Fig. 11) or in the transverse direction (Fig. 1) thereof. In this case, a pivot axis 35 (Fig. 11) or a common axis 19 (Fig. 1) may be provided on either side of the polyester bag 1 in each case. In order to limit the depth of penetration of the cutting blade 17 into the polyester material 2, a depth stop 38 is provided on the cutting blade 17 (Fig. 12 and 13).

In another embodiment of the apparatus, the gripping arms may be used for grasping the packaging film 7 already directly after detaching the packaging film 7 by means of the compressed air injection device 8 and before cutting up with the aid of the cutting device 9.

In this case, individual grippers acting from above, similar to the embodiment of Fig. 5, or a clamp rail which grasps the packaging film 7 from above may be used.

Figs. 14 and 15 show an embodiment in which a rake-like gripper 39 is placed on the upper side of the polyester bag 1 and retains the packaging film 7 in the separation device 6. Then the packaging film 7 is cut up in the direction of conveyance of the conveyor belt 3 on the longitudinal side of the polyester bag 1 with the aid of a longitudinally movable cutting device 41 which is driven by a motor 40. Then the packaging film 7 is removed from the polyester material 2 by lifting up the gripper 39, which sets the polyester material 2 in a rolling motion and causes it to fall from the conveyor belt 3 into the feed cylinder 4 located thereunder (Fig.

15).

As Fig. 16 shows, the gripper 39 for removing the packaging film 7 (process step C) has a plurality of hooks 42 arranged next to one another which hook into the cut packaging film 7, pull it away from the polyester material 2 and scrape off the packaging film 7 on a fixed rake 43 after removal.

In another embodiment of the apparatus, gripping pliers consisting of two elements 44 which are movable relative to each other are used instead of the gripper 39 (Fig. 17). The elements 44 grasp the packaging film 7 and pull it off the polyester material 2. Alternatively one or more suction arms may be placed on the cut packaging film 7 in order to pull it off the polyester material 2.

The direction of operation of the gripper 39 or the gripping pliers 44 or the suction arms may be horizontal, vertical, translatory or rotational, depending on whether the direction in which the packaging film 7 is to be cut is horizontal or vertical.

The disposal of the packaging film 7 may be carried out by mechanical strippers, similarly to the embodiment of Figs. 5 and 6, or without strippers, solely by the gravitational force of the packaging film 7.

Alternatively, suction removal devices or other grippers may be used by means of which the severed packaging film is grasped and removed.

Fig. 18 shows an embodiment of a feed device in which process step D (supplying the polyester material to the injection moulding machine) is carried out with the aid of a movable stop 45 which conveys the polyester material 2 which is freed of the packaging film 7 from a working plane 46 into a collecting container 47 or into the feed cylinder 4 of the injection moulding machine 5.

In another embodiment shown in Fig. 19, the working plane 46 can be tilted with the aid of a hydraulic cylinder-piston unit or other known means in such a manner that the polyester material 2 falls into the collecting container 47 of the injection moulding machine 5 due to gravity. This measure is suitable for all the process steps A, B, C and D. In this case, the working plane 46 may consist of a conveyor belt or a part thereof, by means of which the transportation of the polyester bags 1 to the injection moulding machine 5 takes place.

An embodiment is shown in Fig. 20 in which the gripper 39 is lifted thereby raising the cut packaging film 7 so that the polyester material 2 rolls away and falls into the collecting container 47 of the injection moulding machine 5.

As the diagram of Fig. 21 shows, in another embodiment of the invention the process steps A, B and C are carried out inside the injection moulding machine 5 or in a partial unit 48 of this machine. The partial unit 48 is spatially displaced relative to the injection moulding machine 5 during process steps A, B, C.

Process step D then consists in movement of the partial unit 48 and coupling to the injection moulding machine 5. A possible embodiment of this process step may for instance consist in that the feed cylinder 4 of the injection moulding machine 5 forms the partial unit 48 and can be moved in the horizontal or vertical direction Figs. 22 and 23 schematically illustrate yet another embodiment of apparatus for performing the process according to the invention. In this embodiment, the polyester bag 1 lies on two horizontal flaps 49 forming a support, which flaps are each pivotable downward about a horizontal axis 51 with the aid of a cylinder unit 50. The support for the polyester bag 1 may be one-part or multi-part and either be pivotable downward or horizontally displaceable.

First of all, the packaging film 7 of the polyester bag 1 is inflated according to process step A with the aid of the compressed air injection device 8 (see also Fig.

2 and the description relating thereto). For automation of the operation, the compressed air injection device 8 can be moved in the horizontal direction with the aid of a cylinder unit 52 to insert the hollow needle 10.

Once the packaging film 7 has become detached from the polyester material 2 due to the resulting over-pressure, the packaging film 7 is cut through in the horizontal direction with the aid of the cutting device 17, 22 and 33 according to process step B (see also Figs. 9 and 10 and the description relating thereto). In this case it is advantageous if, when viewed from above, the polyester bag 1 has an oval shape, the long side of which approximately corresponds to the arc described by the cutting blade 17 upon rotation of the arm 33 about the pivot axis 35.

Once the packaging film 7 is cut somewhat more than halfway through, a rake 53 is moved downward with the aid of a cylinder unit 54 and is hooked into the packaging film 7. The rake 53 is attached to the piston rod 55 of the cylinder unit 54 so as to be longitudinally displaceable and lockable for adaptation in length. After hooking into the packaging film 7, th rake 53 is moved upwards again by operating the cylinder unit 54, so that the packaging film 7 is pulled off the polyester material 2. At the same time, the flaps 49 are pivoted downward by operating the cylinder units 50, so that the polyester material 1 falls into the feed cylinder 4 located thereunder or a receptacle 24 of the feed cylinder. By pivoting the cylinder unit 54 which is pivotably mounted on a beam 56 with the aid of another cylinder unit 57, the packaging film 7 is transported to the side and removed. The packaging film 7 is detached from the rake 53 by pivoting the rake 53 about an axis 58 with the aid of a cylinder unit 59, so that the packaging film 7 can fall down into a disposal container 60 (Fig. 23). These measures correspond to process step C "removing the packaging film" and D "feeding to the injection moulding machine".

The sequence of the process steps A, B, C and D may be varied in further embodiments of the invention. The process steps may be carried out successively. However, alternatively individual process steps or all of them may be carried out at the same time.

Claims

1. A process for automatically feeding a machine with a pasty material packaged in an airtight manner in a packaging film so as to form a bag, wherein the bag is fed to a device in which the following process steps are carried out: (A) the packaging film is detached from the sticky material, (B) the packaging film is severed, (C) the packaging film is removed, and (D) the pasty material is fed to the machine.

2. A process as claimed in Claim 1, wherein the process steps are carried out singly or two or more of them are carried out simultaneously.

3. A process as claimed in Claim 1 or 2, wherein the process steps are carried out in the sequence of Claim 1 or in another useful sequence.

4. A process as claimed in any one of Claims 1 to 3, wherein the process step A takes place by producing a pressure difference between the space between the packaging film and the pasty material and the outside of the packaging film.

5. A process as claimed in Claim 4, wherein compressed air is injected into the space between the packaging film and the pasty material.

6. A process as claimed in Claim 4, wherein the bag is introduced into a low-pressure bell or a lowpressure chamber in order to detach the packaging film.

7. A process as claimed in Claim 4, wherein the packaging film is detached by placing suction arms on the outside of the packaging film.

8. A process as claimed in any one of Claims 1 to 7, wherein process step B takes place by means of relative movement between one or more blades and the bag.

9. A process as claimed in Claim 8, wherein the cutting direction of the blade runs in the longitudinal direction of the bag.

10. A process as claimed in Claim 8 or 9, wherein the blade is suspended so as to be rotatable about an axis so that a two-dimensional cut of the bag can be made.

11. A process as claimed in Claim 10, wherein the bag is horizontal and is cut along its longitudinal axis.

12. A process as claimed in Claim 10, wherein the bag is vertical and is cut along a transverse axis 9.

13. A process as claimed in Claim 8, wherein two blades are suspended on a pivoting structure so that a cut is made on both sides of the bag upon the relative movement between the bag and a belt supporting the bag.

14. A process as claimed in any one of Claims 8 to 13, wherein the blade is a driven blade in the form of a sharp disc which is driven directly or indirectly by a motor.

15. A process as claimed in any one of Claims 8 to 14, wherein the relative movement takes place by a translatory force or by a rotational force acting upon the bag or the blade.

16. A process as claimed in any one of Claims 8 to 15, wherein spring pre-stressing of the blade produces a constant contact force of the blade on the bag.

17. A process as claimed in any one of Claims 8 to 16, wherein a depth stop limits the depth of penetration of the blade into the bag.

18. A process as claimed in any one of Claims 1 to 17, wherein process step C is carried out by a gripper which hooks into the bag or the remains of the bag and then pulls it off the pasty material.

19. A process as claimed in Claim 18, wherein the gripper consists of a plurality of hooks and serves to strip the bag off on a rake after removal.

20. A process as claimed in Claim 18, wherein the gripper is moved in a horizontal, vertical, translatory or rotational direction depending upon whether the direction of cutting of the bag is horizontal or vertical.

21. A process as claimed in any one of Claims 1 to 17, wherein process step C is carried out by a gripper which consists of two elements which are movable relative to each other, which can grasp the packaging film like a hand and then pull the packaging film off the pasty material.

22. A process as claimed in any one of Claims 1 to 20, wherein process step C is carried out by a suction device, comprising one or more suction arms which are applied to the packaging film and pull it off the pasty material.

23. A process as claimed in any one of Claims 1 to 20, wherein a rake is provided, the free, downward pointing end of which hooks into the packaging film after it has been inflated, and wherein the rake is drawn upwards with the aid of a cylinder unit after the packaging film has been severed.

24. A process as claimed in Claim 23, wherein the rake is attached to a piston rod of the cylinder unit so as to be longitudinally movable and lockable.

25. A process as claimed in Claim 23 or 24, wherein the cylinder unit is pivotably mounted about a horizontal axis on a beam and, in order to remove the packaging film, can be pivoted out laterally with the aid of another cylinder unit into a position in which the rake with the pulled-off packaging film is located above a disposal container.

26. A process as claimed in any one of Claims 23 to 25, wherein the free, curved end of the rake can be pivoted out laterally about a horizontal axis with the aid of a cylinder unit in order to detach the packaging film.

27. A process as claimed in any one of Claims 1 to 26, wherein process step D is carried out by conveying the bag into the machine with the aid of a movable stop.

28. A process as claimed in any one of Claims 1 to 26, wherein process step D consists in that the working plane for the process steps A, B, C is inclined and the pasty material rolls or falls into the machine.

29. A process as claimed in any one of Claims 1 to 27, wherein the bag lies on a one-part or multi-part support which can be pivoted downward about a horizontal axis in such a manner that the pasty material falls down into a feed cylinder or the receptacle thereof after the removal of the packaging film.

30. A process as claimed in Claim 29, wherein the support consists of two flaps each of which can be pivoted downward about a horizontal axis situated at the outer edge of the flap by means of a respective cylinder unit.

31. A process as claimed in any one of Claims 1 to 30, wherein the machine is an injection moulding machine and the pasty material is a polyester material to be moulded.

32. A process as claimed in Claim 31, wherein process steps A, B, and C take place in the injection moulding machine, or in a partial unit of the machine.

33. A process as claimed in Claim 32, wherein said partial unit is spatially displaced relative to the injection moulding machine during process steps A, B, C, and process step D then consists of a movement towards and coupling to the machine.

34. A process as claimed in any one of Claims 31 to 33, wherein process step D consists in that a gripper which hooks into the bag raises the packaging film until the polyester material rolls into the injection moulding machine.

35. A process as claimed in any one of Claims 1 to 34, wherein the working plane consists of a conveyor belt or part thereof which performs the transportation of the bags to the machine.

36. A process for automatically feeding a machine with a pasty material packaged in an airtight manner in a packaging film so as to form a bag substantially as hereinbefore described with reference to Figs. 1 to 6; or Figs. 1 to 6 as modified by any one of Figs. 7 to 13; or Figs. 14 to 16; or Figs. 14 to 16 as modified by any one of Figs. 17 to 20; or Fig. 21 or Figs. 22 and 23 of the accompanying drawings.