WO1981001534A1

WO1981001534A1 - Process for manufacturing objects such as containers from wood fibrillae and resin and device for implementing such process

Info

Publication number: WO1981001534A1
Application number: PCT/FR1980/000168
Authority: WO
Inventors: P Sorbier
Original assignee: P Sorbier
Priority date: 1979-11-26
Filing date: 1980-11-26
Publication date: 1981-06-11
Also published as: EP0030188A1; FR2470000B1; FR2470000A1

Abstract

Process and device for manufacturing objects such as containers, from a mixture of wooden resine and fibrillae obtained by dry process. A first flat mould (8) is filled with a mixture, the plane shape of the mould corresponding to that of the evolute of the object to be manufactured. A flat precompression of the mixture is effected inside the first mould to obtain a plane rough-cast (62). The plane rough-cast is transferred to the upper portion of a second hollow mould (56); a compression of the plane rough-cast is effected inside the second mould to obtain the finished object (63) which is withdrawn from the second mould.

Description

A method of manufacturing objects such as containers from resin ^{^"and"} wood fibrils and device for its implementation oeuyre

The present invention relates to a method of manufacturing objects such as containers from a mixture of resin and wood fibrils and more particularly from such a mixture obtained by the dry process.

It is already known to manufacture objects from cellulose pulp by the wet method.

_Q This process, which always requires subsequent trimming, is cumbersome and expensive since it requires large investments and a significant expenditure of essentially thermal energy.

A dry process is also known.

It consists in vacuum forming a pulp of cellulose impregnated with resin.

This technique is difficult to master and has an unsatisfactory cost price.

0 The present invention aims to overcome these drawbacks.

To this end, the subject of the invention is a process for the manufacture of objects such as containers, from a mixture of resin and wood fibrils obtained by the dry process, characterized in that one fills, in a filling station, using the mixture, a flat mold whose shape in plan corresponds to that of the development of the object to be manufactured, that the flat mold is brought to a precompression station, that a flat precompression is carried out inside the flat mold to obtain a flat blank, which is transferred to the flat blank

O PI above a matrix, that we fold the blank inside this matrix, that we make a compression, of the rough inside the matrix to obtain the finished object, that l the flat mold is brought back to the filling station, the mixture of resin and wood fibrils is baked in the matrix during compression, and the finished object is removed from the matrix.

This process which leaves the bulk mix to get a _* u finished product can be fully automated. As a result, high productivity can be obtained for a small investment, which allows reduced production costs.

Energy consumption is also reduced.

The mixture of resin and wood fibrils can, for example, be of the type described in French patent No. 78.25.291. Molding is possible with different percentages of the various resins that can be used.

Thus for the production of food packaging, it is possible to use vegetable resins or synthetic resins of the melamine type or else various organic, protein or phospho-protein binders. In the case of non-food applications, thermosetting binders such as Urea-Formol, Epoxy, Polyester or an acrylic or vinyl binder may be used.

This process allows in particular the production of truncated-pyramidal or truncated-conical containers with a depth ranging from a few millimeters to more than 150 millimeters. It is thus possible to manufacture containers with a conicity of the order of 8 to 10 ° and having at their upper part a rim allowing the sealing.

The thickness of the walls of such containers can go down to 3 / 10ths of a millimeter.

The container thus obtained is molded in a single operation without the need for trimming or subsequent finishing.

By suitably choosing the percentage and the nature of the resin used it is possible to obtain porous or impermeable objects with water and grease and, with a starting material of the type of that described in the French patent mentioned above , heat resistant objects, for example for the production of packaging for frozen ready meals.

In one embodiment, the method comprises a step consisting in retracting the ^" edges of the flat mold after precompression to allow the transfer of the planar blank.

The method can also include a step consisting in leveling the surface of the mixture of resin and wood fibrils placed in the first flat mold.

It is also possible to provide for cooking the mixture of resin and wood fibrils in the second hollow mold during compression.

Advantageously, in the method according to the invention, a plurality of first flat molds are driven continuously one after the other from the filling station to the precompression station, then to the station for transferring the blank. flat with the second hollow mold. - -

The present invention also relates to a device for implementing the method described above.

According to the invention, this device is characterized in that it comprises at least one flat mold, means for filling this flat mold with a mixture of resin and wood fibrils obtained by dry process, means for precompressing the mixture in the first flat mold, a matrix, means for transferring the blank formed from the award-winning mixture of the flat mold onto the top of the matrix, means 10 for folding the blank in the matrix, means for compressing the mixing in the matrix and means for driving the flat mold from the filling means to the precompression means, then from the precompression means to the transfer means.

• _] _5 Preferably, the means for folding the blank in the matrix include pushers capable of cooperating with the ejectors of the matrix to pinch and drive the blank to the bottom of the matrix.

Other characteristics and advantages of the invention will appear in the following description of one of its embodiments given by way of nonlimiting example.

In the attached schematic drawings:

Figure 1 is a diagram showing a top view of an installation according to the invention.

Figure 2- is a side view showing a molding unit of the installation of Figure 1.

Figure 3 is a top view of a flat mold according to the invention. FIG. 4 is a side view of the mold of FIG. 3.

FIG. 5 is a front view of the mold of FIG. 3.

FIG. 6 is a side view on a larger scale of the precompression station of FIG. 2.

FIG. 7 is a plan view along line VII-VII of FIG. 6 of the punch used at the precompression station of FIG. 6.

FIG. 8 is a transverse view on a larger scale of the station for opening the flat molds of FIG. 2.

FIG. 9 is a side view of the station for opening the flat molds shown in FIG. 8.

Figure 10 is a top view on a larger scale of the compression station of "Figure 2 in one of its operating stages.

^L a Figure 11 is a view similar to Figure 10 showing the compression station in another stage of its operation.

Figure 12 is a transverse view of the compression station of Figure 2 in one of its operating stages.

Figures 13 to 15 are figures similar to Figure 12 showing in ^* transverse view the compression station in other stages of operation.

The installation shown in Figure 1 has eight molding units (1) as will be described in more detail with reference to Figure 2. Of course a different number of molding units could be provided. FIG. 1 also schematically represents a steel strip (2) whose function will be described below. This steel strip has two parallel strands along which the molding units (1) are arranged. These parallel strands are returned to two pulleys (3), one of which is driven at a suitable speed using a motor not shown.

Figure 2 shows a molding unit in more detail.

Each molding unit generally comprises a filling station (4), a precompression station (5), a station for opening the flat molds (6) and a compression station (7). Flat molds (8) described in more detail below circulate from one station to another of the unit (1) as well as from one unit to another.

If we now refer to Figures 3 to 5 we see shown a flat mold (8).

Each mold (8) essentially comprises a base plate (9) and two mold plates (10). Each p ^'iaque mold (10) has a cutout (11), the blanks (11) once attached with the appearance-shaped cross repré¬ sented in Figure 3. This shape is the object to développœ manufacture which in this case is a package ^food type ^* "tray" as shown in the left part of Figure 2 that is substantially a truncated pyramid provided at the upper portion of its opening with a rim allows ¬ both the sealing.

When the two mold plates (10) are placed on the bottom plate (9) as shown in FIG. 3, it can be seen that the edges of the cutouts (11) define with the bottom plate (9) an enclosure which forms the flat mold proper. Each mold plate (10) is rotatably mounted on the bottom plate (9) using pins (12) passing through bearings (13) integral with the plate (9) and holes made in the plates ( 11). Furthermore, the plates (10) have beyond the axes (12) extensions (14) and the base plate (9) is cut as shown in (15) below the extensions (13).

The flat mold (8) also includes a friction sole (16) at its upper part and a stop (17) at its lower part, the functions of which will be described below.

In addition, an articulated lever (18) is mounted around an axis (19) perpendicular to the base plate (9) and carries on its outer side four permanent magnets (20). Finally the end of the lever (18) opposite the axis (19) is returned by a spring (21) connecting this end to a fixed point (22) of the base plate (9). This spring (21) has not been shown in FIG. 5 for the sake of clarity.

The base plate (9) also supports at its lower part four balls (23) mounted in cages (24) to allow the rolling of the flat mold (8).

The base plate (9) and the mold plates (10) are preferably made of a material supporting repeated bending, for example in glass / polyester laminate.

If we now refer for example to FIG. 8 as well as to FIG. 2 in which the steel strip (2) has not, however, been shown for clarity, we will notice that all along of the installation are provided two raceways (25) on which are likely to come to bear the balls (23) of the molds (8). When the molds (8) are thus arranged, the permanent magnets (20) are then in contact with the steel strip (2) which this fact is capable of driving the molds (8) along the different stations of a molding unit and along the different molding units of the installation.

Furthermore, at the locations where the molds (8) must be stopped, that is to say, as will be seen below, at the precompression stations and at the stations for opening the flat molds, stops have been provided. retractable (26) which, by cooperating with the stops (17) of the molds (8), can stop the progression of these molds. Braking devices, not shown, are also provided upstream of the retractable stops (26) to slow the molds (8) before they stop, in order to avoid shocks which could harm the homogeneity of the distribution of the mixture in the mussels.

These braking members can for example be simple rubber friction pads. When a mold (8) is.

* thus stopped, the permanent magnets (20) slide on the - steel strip (2) without it being necessary to stop it. This mode of displacement of the molds (8) is particularly advantageous because it eliminates the drawbacks of the means of stepwise movement. The adjustment of the installation is thus greatly facilitated.

Furthermore, when the molds (8) pass into the area of the pulleys (3) the lever (18) tilts relative to the base plates (9) as shown in phantom in Figure 3, which allows ensure proper attachment of the molds (8) to the steel strip (2) even in these areas.

The molds (8) are therefore driven as has just been described along the different stations of a molding unit in the direction of the arrows (27) of FIG. 2. These different stations will now be described in more detail detail.

The station (4) for filling the molds (8) is shown on the right-hand side of Figure (2). This position includes essen- tially a storage hopper (28) intended to receive the bulk mixture of resin and wood fibrils. This storage hopper is equipped at its lower part with a pallet distributor (29) of known type.

Furthermore, a recovery hopper (30) comprises at its lower part an exhaust orifice through which its content pours out and mixes with the product dispensed by the dispenser (29).

The recovery hopper (30) has at its upper part a fine mesh fabric (31) and a pneumatic deflector (32). A conduit (33) opens into the axis of the deflector (32) and is supplied by a turbine (34). The turbine (34) sucks through a conduit (35) and a hood (36) the excess product delivered raised by a rotary brush (37) which is itself driven by a motor unit / dimmer (33).

The precompression station which is shown in more detail in Figure 6 comprises a jack (39) to the rod of which is connected a punch (40) shown in plan in Figure 7 and whose shape corresponds to that of the delimited enclosure by the walls of the cutouts (11) of the mold plates (10).

Below the cylinder (39) and the punch (40) a reaction plate. (41) is arranged between the raceways (25). The height of the reaction plate (41) relative to the raceways (25) is such that when a mold (8) is placed below the punch (40) with its balls (23) on the raceways bearing (25), the space (42) between the lower surface of the base plate (9) and the upper surface of the reaction plate (41) is minimal. It is important that when the punch (40) is pressed the bending of the mold (8) does not lead to its destruction. It is for this purpose that the molds (8) are preferably made of a material such as laminate glass / polyester which can withstand repeated bending without being damaged.

Furthermore, a stop (26) is provided at the precompression station (5) to stop the flat molds (8) so that the enclosure delimited by the mold plates (9) is located below the punch ( 40). A friction pad as mentioned above is also provided for slowing down the molds (8) before the stops (26) and (17) are in contact in order to reduce the impact.

0 The opening station for the flat molds (8) is shown in detail in Figures 8 and 9.

This station comprises on the one hand, two jacks (43), the rods (44) of which are provided for pressing on the extensions (14) of the mold plates. (10). ' Through. Furthermore, a ^'May 3 cylinder (45) includes at the lower part of its shank (46) a member (47) which can be put across the path of the mold plates (10) when they are open as will be described below. Finally, ^'two guides (48) are also provided so that, when ad- o surround molds dishes (8), their end engages between the mold plates (10) of the mold plates (8).

Advantageously, a fourth cylinder (70) is arranged as shown in FIG. 8, between the two cylinders (41). At the free end of the rod (71) of this jack (70) is provided a plate (72) capable of coming to press flat on the blank before the rods (44) lift the mold plates ( 10). The plate (72) can be reassembled immediately. that the mold plates (10) have been raised in order to let the blank go flat with the mold (8).

0 A retractable stop (26) is provided in a location as it can, by cooperating with the stop (17) of a mold (8), stop this mold in a position such that the rods (44) of the jacks (43) are located vertically with the extensions (14) of the mold plates (10). Upstream of the stops (26) is arranged a friction pad to cooperate with the friction soles (16) of the molds (8) to prevent them from stopping suddenly.

Figures 10 to 12 show in detail the compression station (7). This compression station essentially comprises a jack (49) carrying at its lower part a punch (50).

another cylinder (51) has a thrust plate (52) on which bear on one side the rod of the cylinder (51) and on the other side of the ejectors (53). The punch (50) carries, facing the ejectors (53)., Pushers (54) retractable biased towards their position out of the punch (50) by elastic means not shown.

The compression station further comprises, disposed on a support (55) a hollow heating mold (56) capable of cooperating with the punch (50), the internal shape (57) of which corresponds to that of the product to be obtained. The mold (56) is provided with holes (58) allowing the passage of the ejectors (53).

The retractable pushers (54) protrude from the punch (50) by an amount sufficient to allow the blank pinched between these pushers and the ejectors (53) to reach the bottom of the mold cavity (57) (56) before the edge (50 ') of the punch (50) arrives at the edge (56') of the mold (56).

Indeed, in the opposite case, it would result at the time of the descent of the punch (50) a cutting of the blank and a pinching of this blank on the peripheral rim (57 ') of the cavity (57) before the draft does not touch the bottom of this cavity.

In addition, the depth of the mold is greater than the developped of the peripheral rim of the imprint, so that it is possible to obtain a molding not requiring subsequent trimming.

The compression station also includes a stop (59), transversely substantially in the shape of a ϋ as seen in FIGS. 12 to 15. This stop is placed above the mold (56) at a height just sufficient to allow passage, between the mold (56) and the lower surface of the stop (59), flat molds (8). This stop (59) also comprises at its upstream part a centering cutout (60) whose function will be described below.

Finally downstream of the compression station (7) substantially horizontal closing bars (61), arranged at a certain height above the raceways (25) and inclined with respect to these raceways, are provided to ensure closure flat mussels.

We will now describe the operation of this installation, first of all, for clarity, assuming that it has only one flat mold, then considering the case where several flat molds are 'arranged the one after the other.

The hopper (28) being loaded with a mixture of resin and wood chips, the pallet distributor (29) allows the passage of a predetermined flow rate of this mixture.

The mixture falls on a flat mold (8) and consequently fills the enclosure delimited by the bottom plate (9) and the walls of the cutouts (11) of the mold plates (10).

VS When the flat mold (8) passes under the hood (36) the mixing excess is lifted by the rotating brush (37) and is sucked by the turbine (34) to be recycled through the conduit (33) in the recovery hopper (30). These products thus recycled are distributed using the deflector (32) and fall back with the mixture coming from the hopper (28). The mold (8) is thus continuously conveyed to the precompression station (5) where it is stopped by the corresponding retractable stop (26).

The jack (39) is then actuated so that the punch

(40) compresses the mixture contained in the enclosure of the mold (8) to obtain a planar blank having sufficient hold.

The jack (39) is then released, which causes the punch (40) to rise, after which the stop (26) is retracted so that the mold (8) is again driven by the steel strip (2).

When the stop (17) of the mold (8) comes into contact with the retractable stop (26) of the mold opening station (6), the mold (8) is again stopped.

After the plate (72) has been lowered using the jack (70), the jacks (43) are actuated so that their rods (44) by pushing the extensions (14) of the mold plates (10) cause the pivoting of these mold plates (10) and the opening of the mold. The plate (72) is then reassembled. The jack (45) is then actuated so that the member (47) is placed as shown in Figure 8 thus preventing the fall of the mold plates (10) so that the rods (44) of the jacks (43) can be reassembled. The stop (26) of the mold opening station (6) is then retracted, so that the mold continues its path towards the compression station (7). Before the rear end of the mold plates (10) exceeds the member (47), their front end engages on either side of the guides (48) so that these plates (10) cannot fall back. The member (47) can then be raised.

When the mold (8) open arrives at the compression station (7), the stop (59) comes into contact with the planar ébau- _Q che released from the mold plates (10) as shown in Figure 12 and thus causes it to slide relative to the bottom plate (9) while the mold (8) continues to move. The planar blank is well centered in the cutout (60) of the abutment (59) and falls to the SUPREME higher part c of the mold ^(56). (Figure ^" 11) ^' .. The mold' 8 continuing its movement arrives at the bars (61) which cause it to close by coming into contact with the mold plates (10).

After leaving the mold (8) the device is in the 0 configuration shown in Figure (13) with the planar blank at the top of the mold (56). The jack (49) is then actuated as shown in FIG. 14 so that the precompressed planar blank is folded in the cavity (57) of the mold (56). The jack (51) is calibrated to offer resistance to the sinking of the ejectors (53) which makes it possible to pinch the pre-compressed planar blank between the ejectors and the pusher, and thus to keep it centered.

The jack (49) being pushed back fully, the final object is molded between the punch (50) and the mold (56) as shown in FIG. 0, the pushers (54) being retracted inside the punch (50). The raising of the jack (49) is controlled by a timing circuit to determine the time

- '

OM cooking which can be of the order of 4 to 8 seconds.

After the jack (49) is reassembled, the jack (51) is actuated, which ensures the extraction, via the ejectors (53), of the finished object (61) as shown in FIG. 2.

In practice, the installation operates continuously as shown in Figure 2.

Several molds (8) are in abutment against each other following the mold (8) which is retained by the stop (26) of the precompression station (5). Another mold (8) is retained by the stop (26) of the mold opening station (6). At the same time, a pre-compressed blank (62) was deposited and centered at the upper part of the mold (56) by the stop (59) while the corresponding mold (8) continued to advance and a finished object ( 6.3) ^was' deposited in the manner described below on the stop (59).

The cylinders (39) of the precompression station (5), (43) and (45) of the mold opening station (6) and (49) of the compression station (7) are then actuated to simultaneously precompress the contained mixture in the mold (8) stopped at the precompression station, open the mold (8) stopped at the station for opening the molds, and ensure the compression of the pre-compressed plane blank (62) deposited on the mold (56).

After the time necessary for baking in the mold (56), the jacks (39), (45) and (49) are raised and the two stops (26) of the precompression station (5) and the opening station of the molds (6) are retracted then immediately reclosed, the first to stop the first mold (8) waiting already filled, and the second to stop the mold (8) which has just been released by the stop (26) of the precompression station (5).

_/ $ W AV Simultaneously, the jack (51) is actiomated to extract from the mold (56) the finished object produced from the blank (62).

The mold (8) released by the stop (26) of the mold opening station (6) resumes its advance so that its front part forming a stop comes into contact with the finished object which has just been extracted from the mold ( 56). Consequently, this mold (8), while depositing its pre-compressed blank at the upper part of the mold (56) pushes the finished object inside the stop (59). This finished object pushes itself the finished object (63) previously deposited in the stop (59), so that it falls between the raceways (25) on a suitable evacuation collector, for example a carpet roller not shown perpendicular to the raceway (25). Such. evacuation collector can be provided for each molding unit (1), each depositing the finished objects that it suits on a general collector collecting the molded objects to all the molding units (1) of the installation shown in Figure 1.

Claims

patent claims

1. A method of manufacturing objects such as containers, from a mixture of resin and wood fibrils obtained by dry process, characterized in that one fills, in a filling station, with using the mixture a flat mold whose shape in plan corresponds to that of the development of the object to be manufactured, that the flat mold is brought to a precompression station, that a flat precompression of the mixture is carried out. inside the flat mold to obtain a planar blank, which we transfer this planar blank on top of a matrix, which we fold the blank inside this matrix, which we perform a compression of the blank inside the matrix to obtain the finished object, that the flat mold is brought back to the filling station, that the baking process is carried out, of the mixture of resin and ^" fibrils" . of wood in the matrix during compression, and that the finished object is removed from the matrix.

2. Method according to claim 1, characterized in that it comprises a step consisting in the retraction of the edges of the flat mold after precompression to allow the transfer of the planar blank.

3. Method according to any one of claims 1 and 2, characterized in that a plurality of first flat molds are continuously driven one after the other from the filling station to the precompression station and then until 'at the transfer station from the flat blank to the second hollow mold.

4. Device for implementing the method according to any one of claims 1 to 3, characterized in that it comprises at least one flat mold, means for filling this flat mold with a mixture of resin and fibrils wood obtained by dry process, means for precompressing the mixture in the first flat mold, a matrix, means for transferring the preform formed from the precompressed mixture of the flat mold onto the top of the matrix, means for folding the blank in the matrix, means for compressing the mixture in the matrix and means for driving the flat mold from the filling means to the precompression means, then from the precompression means to the transfer means.

5. Device according to claim 4, characterized in that the means for folding the blank in the die comprise pushers capable of cooperating with the ejectors. the die to pinch and drag the blank to the bottom of the die.