A METHOD FOR CONVEYING AND DEPOSITING ADHESIVE, FLEXIBLE MATERIAL AND A DEVICE FOR PERFORMING THE METHOD

Abstract: A method for conveying and depositing an adhesive, flexible material (28) by means of a flexible base (10) in right side up position and essentially maintaining its shape on a depositing station (27). The base (10) is supported by a displaceable supporting device (12) equipped with a guiding member (18), which imparts a direction change to the base. The supporting device at the deposition moves away the base below the material thus that this is deposited by means of free fall. The material (28) is positioned on the base (10) a distance from the delivery end of the supporting device (12) corresponding to the acceleration distance of the base (10). One, the rear end of the base (10) is fixedly attached against displacement. The base is teared away from the contact surface in that it is urged to make an abrupt direction change over a guiding member (18) having a very small curvature radius (r) at the front end of the supporting device. The supporting device (12) and the base (10) are simultaneously accelerated rearwardly at an acceleration, which shall be at least 1 g (g = acceleration of gravity), preferably considerably bigger than 1 g.

Description: A METHOD FOR CONVEYING AND DEPOSITING ADHESIVE, FLEXIBLE MATERIA AND A DEVICE FOR PERFORMING THE METHOD The present invention refers to a method for conveying an depositing an adhesive, flexible material by means of a flexibl base in right side up position and essentially maintaining it shape on a depositing station, whereby the base is supported by displaceable supporting device equipped with a guiding member which imparts a direction change to the base, which supportin device at the deposition moves away the base below the materia thus that this is deposited by means of free fall. BACKGROUND OF THE INVENTION Devices for transport and deposition of certain perishabl objects, e.g. cut up slices of sausage, are earlier known fro Swiss patent specification 556285. These known devices can no be used when the material concerned is strongly adhering. Suc materials may be thermosetting plastics, which in the form of dosed sticky mass shall be fed into a heated press, where th actual shaping and setting take place. Another example is thermo plastic resins, which in cold condition are in the shape o plates, which are cut up in accordance with the material consump tion in the mould and which are thereupon heated to about 200°C, whereupon the mass, which is also sticky, shall be introduce into a cold mould, where the shaping and the setting take place. It is possible with this method to produce products, ranging fro rather small size of some square decimeters to such in the siz of several square meters, e.g. at production of entire boa hulls. It earlier has been tried to solve the problem by con¬ veying the sticky mass on a needle bed, but this method ha proven itself to be less suitable, as the mass will stick to th needles and will be difficult to remove when to be deposited. There is further big risk that the mass shall become deformed, resulting in the mass not to be evenly distributed in the mould. The device mentioned in the introduction can neither be used in the design mentioned, as the adherence of the mass is so strong that it will not be released from the belt, but follows this around the pulley at the end of the track, thus that the mass will stick to the lower side of the conveyor belt. PURPOSE AND MOST ESSENTIAL FEATURES OF THE INVENTION The purpose of the invention is to provide a method by which very strongly adhering materials, also in very big slabs, may be con¬ veyed and deposited in a mould without the material undergoing any deformation or coming in contact with any lubricant, intended to reduce the adherence to the conveyor belt, which lubricants may influence the mass negatively. It is necessary that the transfer of the material from e.g. a heating oven to the moulding press can be carried out very swiftly, thus that the material has no time to cool before it reaches the mould. This further implies that the conveyor belt must withstand rather high temperatures. These tasks have been solved in that the material is positioned on the base a distance from the delivery end of the supporting device corresponding to the acceleration distance of the base, that one, the rear end of the base is fixedly attached against displacement, that the base is teared away from the contact surface in that it is urged to make an abrupt direction change over a guiding member of small curvature radius (r) at the front end of the supporting device and by the supporting device and portions of the base being simultaneously moved rearwardly, whereby the centripetal acceleration of the base around th curvature radius (r) of the guiding member is at least 1 g whe the curved portion of the base is below the material. DESCRIPTION OF THE DRAWINGS The invention hereinafter will be further described in form o some embodiments with reference to the accompanying drawings. Fig. 1 shows a section through a first embodiment of a conveyo and deposition device according to the invention, with th conveyor belt in a forwardly extended deposition station. Fig. 2 is a section analogous with Figure 1, but with the con- veyor belt in retracted position, after deposition of material. Fig. 3 shows a second embodiment of the device according to th invention, also in section and having two cooperating conveyo belts arranged in series. Fig. 4 shows the device according to Fig. 3, but with the con- veyor belts in retracted positions. Fig. 5 shows a section through a third embodiment, wherein tw conveyor belts are arranged above each other. Fig. 6 shows a section through the device according to Fig. 5, but with the conveyor belts in retracted positions. Fig. 7 shows in bigger scale a section through the front end portion of the supporting device during the tearing off stage. Fig.s 8 - 13 show sections through a fourth embodiment of the device according to the invention in different operative positions. Fig.s 14 - 17 show sections through a fifth embodiment of the device according to the invention also in different operative positions. Fig. 18 shows the device according to the Figure 14 in a view from above. Fig. 19 shows a section analogous with Fig. 1, through a further embodiment. DESCRIPTION OF EMBODIMENTS The conveying and depositing device according to the embodiment shown in Fig. 1 and 2 comprises an endless conveyor belt 11, which also forms a base (10) for the material 28 to be deposited, and which is driven by a driving device, which is not further shown. The belt 11 is along a portion thereof supported by a supporting device 12. The supporting device 12 consists of a trolley 13, which via appropriate friction reducing means, e.g. wheels 15 is displaceable along guides 14. The trolley 13 sup¬ ports a plate 16 or the like, the front end 17 of which is arranged cantilever-wise and is designed as a guiding member 18, about which the belt 11 is led about 180° to a pulley 19, which is supported in the trolley 13. The belt 11 continues from the pulley 19 to a stationary pulley 20 adjacent a moulding press station 23 and is led back to the upper side of the plate 16 via stationary pulleys 21 and 22. In the last mentioned pulley is furthermore provided a brake 24, by which the movement of the belt 11 can be blocked. By means of a guiding device 25, e.g. in the form of an endless belt 26, driven by a not further shown driving apparatus, the trolley 13 is displaceable towards and away from a deposition station 27, which can be constituted by a mould positioned in said moulding press station 23. The maximum tearing off force available mass σ max = ace • — + flexural rigidity - gravity acceleration area The maximum tearing off force σ e required is dependent on the relation between the surface tension of the belt 10 and the material 28. The lower surface tension the belt has in relation to the material 28, the more will the adherence be reduced (according to the thermodynamical adsorption theory). In order to obtain the required tearing off force between th contact surface of the adhering material 28 and the belt, it is necessary that the belt portion upon which the material 28 rests is pulled away at such a speed, that the tearing off effect aime at is obtained. Practical tests have confirmed this theory an show that the curvature radius r of the guiding member 18, se Fig. 7, has a certain relation to the speed by which the belt i pulled away from the material 28. In accordance with the equatio of forces F=m«a, wherein F = force, m = mass of body and a = acceleration, it is possible - if a is set to be equal to v 2 / where v = is the speed in m/s and r is the curvature radius o the guiding member 18 - to calculate the ratio between th curvature radius r and the speed at which the trolley 13 must b pulled back for obtaining a satisfactory tearing off. It further more has proven itself that the curvature radius r must be smal i.e. the transitory portion between the horizontal and vertica surface of the plate 16 must be almost sharp-edged. A curvatur radius of 5 mm and a pulling speed of 1 m/s gives an acceleratio of 200 m/s 2 , i.e. 20g (g = acceleration of gravity). For reachin the correct speed during the pulling moment, the material 28 i preferably positioned at some distance S from the end of th belt, which distance corresponds to the acceleration distanc required for removing the adherence of the material. Also th surface coating of the conveyor belt 11 is of importance in thi connection and in the present embodiment it has been assumed tha the belt is coated with a coating having a low surface tension, ® e.g. a material on sale under the trade name TEFLON . As the adhering material can consist of big, soft slabs o several meters length and breadth, it is not possible to provid a pulley as a guiding member 18. The friction reduction aroun the guiding member is according to the invention preferabl effected by means of air or gas lubricated bearing surfaces 29, with or without rotatable bearing bodies, and in which opens plurality of channels 30, which communicate with a conduit sys¬ tem system 31 connected to a source (not shown) of pressurize air or the like. The procedure at transport and deposition of an adhering material is the following: A piece of material 28, e.g. a thermoplastic resin, which is adapted to size and thickness, is positioned in the shape of a fixed disc on the rear end of the conveyor belt 11, i.e. the end which is turned away from the moulding press station 23. The conveyor belt passes through a not shown heating oven, wherein the material is heated to e.g. 212° C, i.e. the temperature at which the shaping in the press 23 shall take place. As soon as the correct temperature has been reached, the material 28 is con- veyed to the position shown in Fig. 1, i.e. the distance S from the belt end and just above the deposition station 27. With the material 28 in this position the upper part of the conveyor belt 11 is blocked, by the brake 24 being applied. Immediately there¬ upon the displacement of the trolley 13 is started in the right hand direction in Fig. 7 at such an acceleration, that the speed of the trolley, when the material has reached the deposition station of the guiding member, has reached such a value that cr max is bigger than the required tearing off force σ e . The retraction of the belt takes place to such an extent, that the pressing tool of the moulding press 23 can be activated and presses the deposi¬ ted material 28 to the desired shape. After ejection of the moulded goods and return to initial position of the pressing tool, the trolley 13 is returned to the position shown in Fig. 1. At certain, very heavily adhereing materials it may be necessary to subdivide the tearing off surface into two areas, each one of which is represented by a separate endless belt in the same manner as in the embodiment according to Fig. 1 and 2. In Fig. 3 and 4 such an embodiment is shown, where those two endless con- veyor belts 11a and lib are arranged in series after each other with their deposition ends, i.e the guiding members 18 facing each other. At deposition of the material 28, the conveyor belts 11a and lib, in this case will be pulled away from each other, such as shown in Fig. 4. In certain cases it is necessary that the material 28 during transport from the application thereof on the conveyor belt 11 and up to the deposition, may not alter its shape and for this purpose has been developed the embodiment shown in Fig. 5 and 6. Also in this embodiment are provided two conveyor belts 11a an lib, which are provided with one supporting device 12 each, an which belts are arranged in parallel above each other and at such a distance from each other that there is space for a piece of the material between the belt portions facing each other. In cases where the adhering material shall be subjected to several stages of treatment at different work stations, which can not be aσcomodated by one conveyor belt only it is possible to use the embodiment shown in Fig.s 8 - 13. The adhering material 28 in this example is applied on a base 10, which is constituted by a loose track of material 35, e.g. a plastic film, which in its front and rear ends is reinforced and provided with carriers 36a and 36b in the form of transverse rods or the like, which have such a length that they project outside the supporting device 12, where the rod ends cooperate with appropriate conveyor means provided beside the supporting devices 12. In the same manner as in the embodiments described hereabove the device according to the invention incorporates a supporting device 12, which is displaceable along horizontal guides 14 by means of a not further shown driving device. The supporting device 12 in this embodiment has no endless belt 11, which means that the base 10, i.e. the material track 35, by means of the conveyor device 37 is pulled along the plate 16 of the supporting device 12. At the transport device 37 is provided a carrier member 38, e.g. a hook, which engages behind the rod ends 36a. The conveyor device 37 is preferably constituted by two endless chains positioned along the side edge of the supporting device 12, thus that its entire plate 16 is free and the adhering material 28 may be freely advanced along this. At the lower side of the supporting device 12 is provided a second conveyor 41, also in form of two endless chains on each side of the supporting device 12, and which are each one equipped with a carrier member 42 formed as a hook for cooperation with the front carrier 36a of the base 10. A vertically adjustable stand, which e.g. may be a heating oven is designated 39, and on the shelves thereof are arranged bases 10 with applied adhering material 28. The device operates in the following manner: The adhering mate¬ rial 28, e.g. in the form of a rigid, pre-cut disc is arrange on the base 10 in a predetermined position, e.g. directly in th stand 39 of the heating oven and with the base 10 in a positio in which the carrier members 38 of the conveyors 37 can be inter¬ connected with the front carrier 36a of the base 10, such as shown in Fig. 8. The material pieces 28 in the heating oven ar heated successively and obtain their soft, adhering consistency. Activating the conveyor device 37 causes the base 10 with th material 28 to be pulled over so far upon the plate 16 of th supporting device 12, that the front carrier 36a will be situate a distance outside the front end of the supporting device 12. I this position the carrier 36a is disengaged from the conveyo device 27, with the front edge of the base 10 hanging below th front part of the supporting device 12, such as shown in Fig. 9. The carrier 36a in this position can be interconnected with th carrier 42 of the conveyor device 41. The carrier " 38 of the con veyor device 37 at the same time makes a return movement and i interconnected with the rear carrier 36b of the base 10, see Fig. 10. Having the front and rear ends of the base connected to on conveyor device 37 and 41 each, the front end of the supportin device 12 is displaced into the press 23 above the depositio station 27, such as shown in Fig. 11. With the adhering materia 28 in this position the pulling moment is started, i.e. th supporting device 12 is displaced backwards in a direction awa from the press 23 at a high speed at the same time as the con¬ veyor device 37 remains in immobile position, which means tha the rear edge of the base 10 is held while the conveyor device 4 is activated, which during the entire pulling moment keeps th part of the base 10 situated below the supporting device 12 in stretched condition. During the very pulling procedure the base 10 is pulled over th only slightly rounded front edge of the conveyor device 12 whereby the tearing off takes place between the surface of th base 10 and the contact surface of the material 28, such as show in Fig. 7. The material 28 at this tearing off will remain in th position and shape it occupied before the pulling and it then ca begin to fall vertically down onto the deposition station 27. In certain cases, e.g. when the material 28 is rather thin, o has its centre of gravity positioned thus, that it after havin been teared loose will fall uncontrolled towards the mould 2 and/or if this is inclined, it may be necessary to guide th piece of material 28 during the fall until it has stuck to th mould. This can be effected by means of a guiding member 55 which is displaceable horizontally into and out off the press 23 and which in its activatable position is located above the piec of material 28 introduced in the oven and resting on th supporting device 12. On its side facing the material 28 th guiding member 55 is provided with a number of fork pegs 56 o drawing pin type. The guiding member 55 is displaceable both i horizontal and in vertical direction along suitable guides, thu that the pegs 56 can penetrate into the material 28, such a shown in Fig. 11. After the material having been teared off fro the base 10, the guiding member 55 will accompany the materia during its fall towards the mould 27, Fig. 12, whereby th material is guided in a controlled manner, in that the guidin member is guided in not shown guides. The drawing pin shape o the fork pegs prevent the pegs from penetrating too deep into th material. The guiding member thus guides the piece of material 2 until this has reached the mould 27 and has come to adhere t this, whereupon the member is retracted to its parking positio and is witdrawn horizontally out off the mould, which thereupo makes its pressing operation. It is also possible to co-ordinat the horizontal movement of the guiding member 55 with the move¬ ment of the conveyor 37 and that the guiding member is caused t come to engagement with the material outside the press 23. The base 10 thereupon can be fed to a catching device 43, whic possibly may be a further conveyor belt. During the very pressin operation the stand 39 is fed one step upwards, thus that a ne piece of material 28 can be pulled in on the supporting device 12. The handling of the adhering material 28 requires in the embodi¬ ment according to Fig.s 8 - 13 a comparatively long base relative to the size of the material, which in certain cases can be a drawback. In the embodiment according to Fig.s 14 - 18 is shown an arrangement wherein the base 10 needs be only slightly bigger than the adhering material 28. The base 10 also in this embodiment is pulled in on the suppor¬ ting device 12 by means of a conveyor device 45 consisting of two endless wires situated outside the supporting device 12 and alon its two side edges. The conveyor wires 45 are led about pulleys 46 and 47 supported at the rear and front edge resp. of th supporting device and about two fixedly arranged pulleys 48 and 4 ' 9. For the sake of clarity the pulleys 48 and 49 in Fig.s 14- 17 have been pulled out somewhat from the pulleys 46 and 47 i order clearer to show that the conveyor wire is arranged in for of an eight. Each one of the conveyor wires 45 is provided wit one carrier 50 in the form of a hook, a peg or the like, whic engage behind the front rod ends 36a of the base 10, such a shown in Fig. 14 and 18. The carriers 50 pull the base 10 up t the front end of the supporting device 12, in which position second conveyor 51 equipped with a carrier 52 interconnects thi with the rear rod 36b of the base 10, such as shown in Fig. 15. The supporting device thereupon may be displaced in its guid thus that its front end portion will be situated in the press 23, illustrated in Fig. 16. The very pulling is effected by means of the driving unit 53, which drives the conveyor belt 45, and which by means of th carrier 50 on one hand causes the desired tearing off but on th other hand also gives the supporting device 12 a return movemen out off the press 23, such as shown in Fig. 17. Certain materials 28 has such consistency that they are not shap permanent. It can also occur pieces of material 28, which ha such height that they during transport to the press must b backed up. This can be effected according to the invention b means of a supporting member 57, shown in Fig. 19, which support or shapes the material up until the tearing off from the base 10 In Fig. 19 is shown an annular supporting member 57, but this ma of course have any other desired shape. The supporting member 5 is supported by an arm 58, which via wheels 59 is guided in guide 60. The arm 58 cooperates with two shoulders 61 fitted t the base 10, which in the embodiment shown is an endless belt The supporting member 57 has no bottom, but this is formed by th base 10, which during the tearing off moment leaves the lowe side of the supporting member, thus that the material 28 may fal downwards. The shaping or supporting space 62 of the supportin member may possibly be designed so that it may be attached to source of pressurized air intended to press out the material 28.

Claims: CLAIMS 1. A method for conveying and depositing an adhesive, flexible material (28) by means of a flexible base (10) in right side up position and essentially maintaining its shape on a depositing station (27), whereby the base (10) is supported by a displace¬ able supporting device (12) equipped with a guiding member (18), which imparts a direction change on the base, which supporting device at the deposition moves away the base below the material thus that this is deposited by means of free fall, c h a r a c t e r i z e d t h e r e i n that the material (28) is positioned on the base (10) a distance from the delivery end of the supporting device (12) corresponding to the acceleration distance of the base (10), that one, the rear end of the base (10) is fixedly attached against displacement, that the base is teared away from the contact surface in that it is urged to make an abrupt direction change over a guiding member (18) of small curvature radius (r) at the front end of the supporting device and by the supporting device (12) and portions of the base (10) simultaneously being moved rearwardly, whereby the centripetal acceleration of the base around the curvature radius (r) of the guiding member (18) is at least 1 g when the curved portion of the base (10) is below the material (28). 2. A device for performing the method according to claim 1 for conveying and depositing an adhesive, flexible material (28) by means of at least one flexible base (10), at least one supporting device (12) supporting the base (10) and being displaceable in longitudinal direction, and equipped at one of its ends with a guiding member (18), designed to impart upon the base a direction change, a blocking device for blocking the base, and a first driving device for displacing the base (10) and a second driving device for driving the supporting device (12), c h a r a c t e r i z e d t h e r e i n, that the base (10) is coated with a coating having a low surfac tension, and that the movable supporting device (12), which supports the bas (10), which during the tearing off is fixedly attached to th rearmost end thereof, is moveable rearwardly in a direction awa from the deposition station (27) at such a speed that the fron part of the flexible base at the front end edge (18) of the sup porting device is brought to make an abrupt direction change an a centripetal acceleration around said end edge of at least 1 g 3. A device as claimed in claim 2, c h ar a c t e r i z e d t h e r e i n, that the base (10) is constituted by an endless, drivabl conveyor belt (11). 4. A device as claimed in claim 2, c h a r a c t e r i z e d t h e r e i n, that the base (10) is constituted by a loose material track, e.g.. a plastic film, both ends of which are alternatingl σonnectable to a driving device (37, 41), and the front end o which during the deposition is connected to a stretching devic consisting of a second driving device (41) or a resilient member. 5. A device as claimed in claim 2, c h a r a c t e r i z e d t h e r e i n, that the base (10) is constituted by a loose material track, bot ends of which are connectable to one carrier member (36a, 36b each provided on an endless, drivable conveyor belt (45). 6. A device as claimed in claim 2, c h a r a c t e r i z e d t h e r e i n, that the guiding member (18) is provided with friction reducin means in form of air- or gas-lubricated bearing surfaces (29). 7. A device as claimed in claim 2, c h a r a c t e r i z e d t h e r e i n, that two supporting devices are arranged in series after each other with their deposition ends facing each other and in close connection to each other and being directed towards a common deposition station (27), the supporting device (12) of each conveyor belt (11a,lib) at deposition being displaceable in a direction away from each other. 8. A device as claimed in claim 2, c h a r a c t e r i z e d t h e r e i n, that two conveyor belts (11a,lib) are arranged in parallel above each other with their active belt parts facing each other, and between which the adhering material (28) is intended to be conveyed, and that the driving devices for the supporting devices (12) are synchronized and adapted to be displaced simultaneously in the same direction. 9. A device as claimed in claim 2, c h a r a c t e r i z e d t h e r e i n, that above the deposition station (27) and above the movable supporting device (12) is provided a guiding member (55) with vertically provided pegs (56), and that the guiding member (55) is vertically movable and adapted during the falling motion of the material towards the deposition station (27) to guide the material (28) by holding the pegs (56) in contact therewith. 10. A device as claimed in claim 2, c h a r a c t e r i z e d t h e r e i n, that a forming or supporting member (57) intended to receive th material (28) is positioned/positionable upon the base (10), tha the base (10) is arranged to form the bottom of the supportin member, and that the supporting member (57) is horizontall displaceable to and from the deposition station (27).

Inventors: PALMERS GOERAN, PALMERS, GOERAN
Applicants: INST VERKSTADSTEK FORSK IVF, INSTITUTET FOER VERKSTADSTEKNISK FORSKNING
Application year: 1988
Main classification: B29C31
IPC codes: B29C31, B29C43, B65G49