FR3038588A1 - METHOD FOR PACKAGING AN OBJECT WITH IRREGULAR SHAPES - Google Patents

Abstract

The invention relates to a method for packaging an irregularly shaped object (M), where the object is carried by a layer of expanded polymer foam deposited on a rigid support (1), the object being placed on a thickness of foam layer during curing, such that the layer once its complete expansion coats the entire underside of the object and its side walls on at least 20% of its height.

Description

METHOD OF PACKAGING AN OBJECT TO SHAPES

IRREGULAR

The invention relates to a method of packaging an object with irregular shapes. It is particularly interested in objects belonging to powertrain groups, for example those equipping means of locomotion such as land vehicles - such as motor vehicle -, maritime or air, or those used for purposes other than the propulsion of vehicles.

In the following text, we will take the example of a thermal type of motor, for the sake of brevity and simplicity, the invention being of more general application.

[0003] The conditioning of engines for storage and transport is generally a time-consuming operation of operator and packaging material.

Indeed, because of their irregular shape and their variable size from one model to another, it is necessary to provide, for each engine model, a specific means of packaging. It is thus known to proceed to the conditioning of a given engine in the following way: a wooden pallet is placed on the ground which will constitute the rigid support of the engine, on which a polymer plate, for example made of polystyrene, is placed. is specially designed for the model of engine to be conditioned, and on which one comes to deposit the motor. Then comes to place at least one crutch resting on the pallet to support and wedge laterally the engine. The engine is then held on its pallet using straps. We see that this conditioning requires a succession of operations, and that for each model it will be necessary to design a polystyrene plate adapted with a number of crutches whose number, size and positioning must also be adapted, not to mention the storage management of these plates and crutches before use.

It is also known from US-3,237,760 a packaging technique which implements a layer of polymer foam on which it is placed the object to be packaged before the foam has fully cured, so as to what the underside of the object puts its imprint on the foam layer. This technique avoids having to manage different polymer plates as in the previous technique, on the other hand it requires other means to wedge in position the engine, proposing to cover the upper part of the object with another layer preformed foam of adequate shape / size to fit the side and upper walls of the object, which is thus entirely "caught" in the foam. This solution is a progress but is still subject to improvement, since it requires a lot of foam material, the upper part of which must be preformed before coming to cover the object.

The invention therefore aims to improve the packaging of irregularly shaped objects. It seeks in particular to develop packaging processes requiring fewer operations, and / or faster, and / or easier to implement.

The invention firstly relates to a method of packaging an object with irregular shapes, where the object is carried by a layer of expanded polymer foam deposited on a rigid support, the object being placed on a thickness of the foam layer during curing, and such that the layer once its complete expansion coats the entire underside of the object and its side walls on at least 20% of its height.

The invention also relates to the object thus conditioned on the rigid support with the foam.

The invention thus proposes to use an expanded foam material to serve as a support for the object, not only to wear its lower face, but also to support / maintain laterally on a minimum height of 20%: the foam, which is created in situ at the moment when the object is conditioned, thus plays the role of structuring foam, holding perfectly the object without resorting to wedges or crutches that must be done , store, position and remove, or need to fully wrap the object. The foam can marry precisely the shape of the underside and the lateral faces of the object to a predetermined height and sufficient to allow this maintenance.

Preferably according to the invention, the foam layer, once its expansion is complete, surrounds the side walls of the object on at most 50%, in particular at most 40 or 30% of its height. This ensures a sufficient maintenance of the object while limiting the amount of foam to use and allowing easy extraction of the object when we want to decondition.

According to one embodiment of the invention, the expanded foam layer is created on the rigid support in several steps, comprising an initial step where a precursor foam mixture is deposited on the rigid support to create a first expanded foam layer, a subsequent step of placing the object on said first foam layer being cured, and then a subsequent step of depositing precursor foam mixture on the first layer of foam foam around the object to make a second layer of foam.

According to another embodiment, the foamed foam layer is created on the rigid support in a single step, positioning the motor above the rigid support during the deposition of the layer.

The first step is to ensure that there is a sufficient thickness of foam between the object and the rigid support, before continuing the constitution of the foam so that it also surrounds the walls sideways on a defined height.

Preferably, there is interposed between the foam layer and the object a film, in particular a plastic film. This avoids any phenomenon of mutual adhesion between the foam and the object that would interfere with its extraction or require cleaning of the object thereafter. With an interlayer film, the object is not in contact with the foam, but with the film, which is chosen from a material that does not adhere to the object in question.

This film can also come pack the walls of the object out of the foam layer.

Advantageously, the foam layer is confined to the rigid support with a template, preferably interposing a film between the entire rigid support and the template and the foam.

According to one embodiment of the invention, the object is placed in a portion of the foam layer thickness being hardened by maintaining it in a given position using a lifting tool. from the object until the end of the curing of the foam, for example using a rudder (hoist) equipped with one or more slings.

According to one embodiment of the invention, the expanded foam is based on polyurethane, in particular obtained from a liquid mixture of precursors based on diisocyanate diphenylmethane and diisocyanate 4,4'-methylene diphenyl. The layer is then deposited by spraying / spraying a liquid reaction mixture onto a support, which becomes a gradually hardening layer of foam.

We can complete the conditioning of the object by placing a cap on the periphery of the rigid support, which comes to completely cap the object, and which is optionally strapped around the rigid support.

The invention also relates to the application of the method described above to the conditioning of propellant group components, including thermal engines.

The invention is described in more detail below using a non-limiting embodiment, illustrated with the aid of the following figures. This example relates to the conditioning of a heat engine for transport. - Figures 1 to 8 show steps of the engine conditioning method according to the invention and were made from photos.

All these figures are to be considered as schematic and not necessarily to scale.

Throughout this text, one understands the spatial references of the type "high", "low", "superior", "lower", "above", "lateral" etc ... as referring components described in their mounting / packaging positions.

FIG. 1 represents a wooden pallet 1 on which a cardboard template 2 has been placed in a first step, on the periphery of the pallet 1, so as to jointly define a cavity 3 defined by a lower wall constituted by the pallet and side walls constituted by the template, the cavity being open at the top. This cavity 3 delimits a substantially parallelepipedal volume, with a rectangular base of about 2 m by 1.5 m and a height of about 0.4 m. The pallet 1 has been placed near a dispensing device 4 of plastic film 5 in the form of a roll of continuous film.

FIG. 2 represents the following step, where the dispensing device 4 is unfolded to cover the cavity 3 with a plastic film 5, the film 5 being then cut to the appropriate dimensions to completely cover the template 2. .

FIG. 3 represents the following step, where the film 5 is positioned once cut in the cavity 3, so as to cover the entire internal walls of the cavity 3.

FIG. 4 represents a packaged heat engine (visible in FIG. 8 under the reference M) in a plastic bag 6 and which is positioned above the pallet 1 with the aid of a hoist (FIG. not shown) equipped with slings 7 supporting the engine. We come using the hoist to center the motor above the pallet 1 and lower it in the cavity 3 so as to leave about 10 cm to 20 cm of vacuum between the bottom of the cavity 3 and the bottom of the engine.

Figure 5 shows the step of approaching the cavity 3 a gun 8 which is fed from a tank (not shown) by a suitable pipe, a liquid mixture of chemical precursors to create a foam expanded polyurethane. This mixture is based on diphenylmethane diisocyanate and 4,4'-methylene diphenyl diisocyanate. It is in particular marketed under the trade name Instapak® A. It is therefore sprayed the liquid mixture with the gun 8 at the bottom of the cavity 3 under the engine wrapped, over the entire bottom of the cavity 3. It then obtained in a few seconds a foam 9 of substantially homogeneous thickness covering the entire bottom of the cavity. It is filled by the foam 9 the vacuum between the bottom of the cavity 3 and the lower part of the engine. This first layer of foam is allowed to polymerize for about 30 seconds.

Figure 6 shows the next step of placing the hoist with the motor wrapped 6 on the layer being hardened, while maintaining the engine support by the hoist to prevent tilting of the engine .

Figure 7 shows the next step of spraying a second layer of mixing with the gun 8 all around the engine packaged 6 in the cavity 3, so that, once the foam layer is complete, all the wrapped motor edge is coated with foam for at least 20 to 30% of its height.

Figure 8 shows the last step: The two successive layers of foam 9 are allowed to cure completely, the template 2 is removed, then the film 5 is folded over the foam 9, and the "unpack" can be unpacked. motor M, in its emergent part of the foam 9, its plastic bag 6. It is also possible to add a "cap" cardboard above the engine and coming to the periphery of the pallet 1, if the means provided for transporting the motor require it, but it is as additional external protection, not to have a mechanical role with respect to the engine M.

There is thus an engine M which is embedded in a foam roll 9 to a height sufficient to support, protect and wedge. It is no longer necessary to use wedges, crutches to ensure its maintenance. There are no more holds to design and store. There is no longer any need to make cut polystyrene support layers adapted to each motor to be transported. The packaging process is very fast, since the mixture is transformed into foam almost instantly, and cures completely in one or more minutes (depending on the amount of foam used), and is easily done by a single operator. The foam can be used for a given type of engine. The motor can be easily extracted from the foam layer, since a film thickness 6 of plastic is sandwiched between the foam and the motor.

Variants in the manner of depositing the foam layer 9 are possible: thus, instead of three separate steps (it is a first spray, the engine is positioned, it is a subsequent spray around the engine), we can do a single continuous spraying, keeping the motor at the appropriate height in the cavity during the entire spraying phase.

It is also possible to also coat, beside the engine or the "main" object of other objects, for example accessories to the engine (to the main object), in the same way as for the main object: packing in a plastic bag, positioning next to the motor. This can be, for a heat engine, a turbocharger component for example.

Claims (10)

1. A method of packaging an object (M) with irregular shapes, wherein the object is carried by a layer (9) of expanded polymer foam deposited on a rigid support (1), the object being laid on a thickness layer of foam during curing, characterized in that the layer once its complete expansion coats the entire underside of the object and its side walls on at least 20% of its height. 2. The method of packaging according to the preceding claim, characterized in that the layer (9) once its expansion is completed coats the side walls of the object (M) by at most 50%, in particular at most 40 or 30% of its height. 3. The method of packaging according to one of the preceding claims, characterized in that the layer (9) of expanded foam is created on the rigid support (1) in several stages, comprising an initial step where a mixture is deposited. precursor foam on the rigid support to create a first expanded foam layer, a next step where the object is placed on said first layer of foam during curing, then a next stage where the precursor foam mixture on the first foam layer expanded around the object to make a second layer of foam. 4. A method of packaging according to one of claims 1 or 2, characterized in that creates the layer (9) of expanded foam on the rigid support (1) in a single step, positioning the motor (M) to above the rigid support during the deposition of the layer. 5. A method of packaging according to one of the preceding claims, characterized in that interposed between the foam layer (9) and the object a film (6), in particular a plastic film. 6. Packaging method according to one of the preceding claims, characterized in that the foam layer (9) is confined on the rigid support (1) with a template (2), preferably interposing a film (5). between the entire rigid support and the template and the foam (9). 7. The method of packaging according to one of the preceding claims, characterized in that the object (M) is placed in a portion of the thickness of the layer (9) of foam during curing by maintaining it in a position given using a lifting tool of the object until the end of the curing of the foam, for example using a rudder equipped with one or more slings (7). 8. A method of packaging according to one of the preceding claims, characterized in that the expanded foam (9) is based on polyurethane, especially obtained from a liquid mixture of precursors based on diphenylmethane diisocyanate and diisocyanate. isocyanate 4,4'-methylene diphenyl. 9. Method according to one of the preceding claims, characterized in that terminates the conditioning of the object (M) by placing a cap on the periphery of the rigid support (1), which comes to completely cap the object, and which is optionally strapped around the rigid support. 10. Application of the method according to one of the preceding claims to the conditioning of propellant group components, including heat engines (M).