FR2654057A1 - Trolley for catering and method relating thereto for producing an articulated wall - Google Patents

Abstract

Trolley for catering (1) in the form of a parallelepiped provided with two opposite lateral doors (6) and the longitudinal walls (3, 4) of which exhibit, on their internal surfaces, pairs of grooves (17) forming slideways for meal-trays (19). The various walls (3, 4, 5, 7) and the doors (6) are double-skinned walls, each skin being made from a relatively rigid resin, comprising between these skins a filling made from synthetic foam ensuring a connection between the two skins. Furthermore, the doors (6), in the closed position, are set into corresponding openings in the framework and each door hinge (11) has its two hinge straps held respectively between the two skins of one same wall (4) and the two skins of a door (6), these straps additionally being anchored in the intermediate synthetic foam. Application to the production of a very robust catering trolley which, however, remains lightweight and of low cost.

Description

 The present invention relates to a catering trolley, intended in particular to be used in rail, air or sea transport vehicles.

 It relates in particular to a carriage in the general shape of a parallelepiped and in particular a carriage provided with two doors constituting in service the front and rear walls of the carriage.

 A trolley of this kind, filled with meal trays intended for passengers, must be capable of being carried when it is introduced into the vehicle. This implies that the trolley is as light and robust as possible.

 For this purpose, metal constructions have hitherto been used in general, at least for the framework of the carriage. Such a structure, even optimized, is relatively heavy, and it is also quite expensive. She tends to get tired over time, which results in the appearance of games.

 The object of the present invention is to provide a trolley for catering, very robust, while being light and of low cost, and moreover having great ease of use.

 The present invention relates to a trolley for ia catering, in particular in rail, air or sea transport, comprising a structure in the general shape of a parallelepiped comprising fixed walls and two pivoting walls for the use of doors in two opposite lateral faces of the parallelepiped, characterized in that at least some of said walls are part of a set of double skin walls comprising an inner skin and an outer skin, both made of relatively rigid resin and, between these two skins, a filling of synthetic foam ensuring a bond between the two skins.

 According to an advantageous version of the invention, the carriage comprises two half-frames, each of which is formed by an inner half-shell and an outer half-shell connected by an intermediate layer of synthetic foam.

 The invention makes it possible to produce a trolley whose structure, formed of a double skin of molded resin with intermediate filling of synthetic foam, gives it great robustness and great resistance to deformation, at the same time as a reduced weight. As far as manufacturing is concerned, a small number of molds suffices to make the frame and the doors, so that a production cost is obtained which is considerably lower than that of conventional carriages. In addition, the carriage thus produced no longer has slots and recesses which are impossible to clean. On the contrary, the carriage can be cleaned very completely with a pressurized simpie jet, which is very favorable for hygiene.

 In addition, the walls according to the invention have thermal insulation properties which are sought in this type of trolley to avoid cooling of the dishes during their distribution to the passengers of the train or the plane. The athermic bridges formed by the metal framework of the prior art are eliminated.

 The robustness of this carriage is further increased if the two doors are in the closed position, fitted into the frame. Thus, the doors stiffen the frame, and moreover can transmit a vertical force, directly to the frame, when the carriage is carried by handles fixed to the doors.

 According to a shaking aspect of the invention, the method for producing a wall provided with a hinge, in particular in the context of the manufacture of a restoration trolley, is characterized in that an internal skin and an external skin are produced on respective models, a hinge hinge is placed on the inner face of a first skin, by positioning a body of the hinge in a recess linked to the model of a first skin to position the body of the hinge axially, cooperate the body of the hinge with a radial positioning means, the two models are assembled so that the two skins have the desired position relative to each other to form the wall, then foam is injected between the two skins.

 A wall is thus produced which, in addition to the qualities mentioned above, includes a hinge which is fixed to it in an exceptionally stable manner over time, even if this hinge undergoes in service the forces due to the carrying of the full carriage by means of handles. attached to the front and rear doors thereof.

Other features and advantages of the invention will become apparent during the description which will be given of an embodiment of the invention, by way of non-limiting example, with reference to the appended drawings in which
- Figure i is a schematic perspective view of a carriage according to the invention;
- Figure 2 is an end view of the carriage of Figure 1, the door being assumed closed and partially broken away;
- Figure 3 is an enlarged partial section along line III-III of the door shown in Figure 2
- Figure 4 is a longitudinal section along
IV-IV of Figure 2, the doors being assumed not to be assembled, showing the location of the meal trays
- Figure 5 is an enlarged view of the detail V of Figure 2
- Figure 6 is a section on VI-V- of Figure 4, the doors being in the open position, with cutaway
- Figure 7 is an enlarged bowl view of detail VII of Figure 6, showing the region of a hinge, the closed and open positions of the door being shown one in solid lines and the other in mixed line
- Figure 8 is a perspective view of a door hinge being assembled
- Figure 9 is a sectional view on an enlarged scale along IX-IX of Figure 4 showing the connection of the half-frames
- Figures 10 to 12 schematically show three stages in the production of one of the half-frames
- Figure 13 is a section along XIII-XIII of Figure 10
- Figure 14 shows schematically on a larger scale the anchoring of a hinge hinge in a longitudinal wall of the carriage
- Figure 15 is a schematic perspective view showing the installation of a hinge between the two shells of one of the side walls; and
- Figure 16 is a view similar to Figure 14 but relating to one of the doors.

 A carriage 1 according to the invention comprises a carriage body or frame in the general shape of a parallelepiped comprising two longitudinal walls 3, 4, a floor 5 and an upper wall or table 7. The frame has two openings occupying substantially both of them front and rear end faces to the parallelepiped. These two openings can be closed by two doors 6 hinged to the same wall 4 by means of hinges 11.

 The frame is formed by two half-frames 10, 20 (see FIG. 9) which, seen from the front, have a general U shape with horizontal branches and each of which is itself formed by a skin or half-shell. inner resin 16, 26 and an outer skin or half-shell also resin 18, 28, the inner and outer shells being connected by a synthetic foam 30, for example a polyurethane foam or a phenolic foam. The two half-frames 10, 20 each define a half-floor and a half-table, and are connected to each other according to two joining surfaces 32, 34, 103 extending from an opening to the another in the vicinity of the median longitudinal plane P of the frame.

 At each junction surface, the edges of the interior and exterior shells of the half-frames are adjacent along respective junction lines 32, 34 offset laterally with respect to each other so that each junction line 32 or 34 is opposite a continuous region of another shell, which stiffens the connection between the two half-frames, produced for example by gluing or by a welding process compatible with the plastic used. The junction lines 32 and 34 are also spaced from each other, in a vertical direction, and, between them, the foam of the two half-frames forms a part i03 of the junction surface.

 The main steps of an embodiment of the carriage will be indicated later, with reference to FIGS. 10 to 15.

 Each of the walls 3, 4 has in its upper part an attached extension forming a rim 13 for the table 7, the two rims 13 being connected at their ends by gripping bars 15, useful for pushing the trolley in the aisles and / or corridors of the vehicle.

 Four supports 12, fitted with self-orientable rollers 14 for moving the carriage, are fixed to the underside of the floor 5.

 On the internal faces of the walls 3, 4 are provided grooves 17 arranged parallel to the floor 5 and intended to receive trays 19 on which are placed the dishes to be distributed to passengers.

 Like the fixed walls of the carriage, the doors 6 are "double shell", that is to say that they comprise an inner skin 22 and an outer skin 24 connected by synthetic foam 30 (see FIG. 7). The two skins 22, 24 meet substantially along the periphery of each door, so that the thickness of the door at its periphery is very much less than its thickness in the central part. For this1 the outer skin 24 has a rectilinear transverse profile, while the inner skin 22 has, from each edge, a part pressed flat against the inner face of the outer skin, then a bend in the direction opposite to the outer skin and another bend to then extend substantially parallel to the outer skin.

 Similarly, the outer skin 18 of the half-frames has, parallel to the longitudinal edges of the frame, a straight profile (see FIGS. 6 - 7), while the inner skin 16, 26 a, in the vicinity of the edges defining each opening of the frame. , a profile such that, from the edge, the inner skin is first applied flat against the inner face of the outer skin, and thus forms around each opening a peripheral lip 80, then has a bend 116 in the opposite direction to the outer skin and a counter-bend 216 to then extend substantially parallel to the outer skin 18, at a distance from the latter. The inner shells 16, 26 thus have, around the openings of the frame, a 3: 6 shoulder against which the doors 6 bear in the closed position.

 Each of the door hinges 1 comprises a body consisting of cylindrical housings 36 and 38, crossed by a common axis 37, which are alternately fixed to one or the other of two hinges fixed one to the door 6 and l to the other wall 4. Each hinge (see also FIG. 8) comprises a first plate 35 which is integral with the aligned cylindrical housings 36, or 38, and a second plate 39 comprising orifices 40, welded in overlap on the first plate 35 by a longitudinal weld bead. As shown in FIG. 7, each hinge is engaged between the two skins of the door 6 or of the wall 4, with the plate 35 against the flat outer skin 18 or 24 and the plate 39 separated from the two skins, which anchors the hinges in the intermediate synthetic foam 30 after solidification of the latter in particular on either side of the plate 39 and through the orifices 40 thereof.

 In the closed position (solid line position in FIG. 7) the doors 6 are fitted into the openings of the frame, that is to say that the peripheral lip 80 (FIG. 2) of the frame surrounds the lateral faces with little play. of each door. In this position, the seal is ensured by means of a seal which can be an elastomer seal 21 fixed on the periphery of the interior face of the door 6 as shown in FIG. 1, or on the interior periphery of the opening, as shown in Figure 7, although the latter solution has the disadvantage of exposing the seal to deterioration during the insertion and extraction of meal trays.

 It is also possible to provide sealing by simple mutual contact of the interior skin 22 of the doors with the interior half-shells 16, 26 of the half-frames.

 The purpose of the desired tightness is to limit the heat exchanges between the interior volume of the carriage and the exterior atmosphere. Thanks to the interlocking of the doors 6 in the closed position, the heat exchanges are greatly reduced. They are all the more so since the very low deformability of the resin skins constituting the doors and the frames makes it possible to provide very little play at the nesting level, without risk of jamming after a certain time of use of the carriage.

 As shown in Figure 6, the two doors 6 pivot 2700 from their closed position to the fully open position shown, where they are folded against ia same side wall, namely the wall 4. Pairs of magnets 82 (see Figure 6) arranged at the base of the panels forming the doors 6 and the wall 4, inside these panels, but close to their outer surface, at substantially the same distance from the axis of the corresponding hinges, maintain firmly, removably, the doors 6 in the fully open position when they have been brought there.

 To the panel of the door 6 is fixed a lock 25 (FIG. 1) having a bolt 27 which can engage in a keeper 29, itself fixed to the wall 3 by being caught between the inner and outer shells respectively of the wall 3.

 The outer shell of the door 6 has a slot-shaped recess constituting a grip handle 31 for the carriage (see FIGS. 2 and 3).

When the doors 6 are closed, two people can grab the wagon on either side and lift it, for example, to make it cross one or more steps at the entrance of the vehicle. The force exerted by the people thus carrying the trolley is located in the plane of each door and is reflected on the frame due to the swirling, thereby resulting in only a minimum of moments on the doors, the hinges , etc ...

 To facilitate gripping, the recess made in the exterior skin of the door comprises a skin portion 33 folded upwards.

 The carriage is intended to receive two columns of a dozen meal trays 19 each of which two opposite edges are arranged in cut grooves 17 forming slides and designed for introduction and exit of the trays by one or the other. openings according to the column considered (see Figures 4 to 6). To facilitate handling, the grooves 17 have an upper rim 43 set back from a lower rim 41 on which the meal tray 19 rests. After its introduction into the carriage, the tray 19 is positioned by means of a stop 45, which can be constituted by a metal insert in the Inner shell At both ends of the carriage, the grooves 17 are arranged in alternating overlap so that the plates can partially overlap in the central part of the carriage in order to save space.

 Note that the profiles of the grooves 17, both longitudinal (Figure 6) and transverse (Figure 5) have rounded shapes. Thanks to this absence of projecting angles capable of retaining particles of food and of interfering with the periodic cleaning of the interior of such carriages, it is possible to substantially improve the hygiene of the installation.

 To make the carriage according to the invention described above, it is possible to proceed as shown in FIGS. 10 to 15.

 First, the inner 16 and outer 18 shells of a half-frame are produced separately.

 To do this, we begin by making (see FIG. 10) a convex model 51, for example of wood, whose exterior shape is identical to the shape of the interior surface of the interior shell 16 of a first frame of the carriage 1. The periphery of the base of the model 51 is fixed to a support 52 by known means such as bolts or screws 53. Then, a mixture of fibers and polyester resin is sprayed onto the external surface of the model so as to form a layer of 'substantially equal thickness. Instead of spraying a mixture, you can also apply several successive layers to the surface of the model, each formed of a glass wool fabric impregnated with polyester resin. After solidification, the inner shell 16 of the demibâti in question is obtained, the shape of which is demoldable. In the case of a panel produced with layers of glass wool fabric superposed, it is possible to insert at the base of the wall 4, between two layers close to the outer surface, the magnets 82 intended to apply firmly, the doors 6 in the fully open position against the wall 4.

 In a second step which may precede, follow or be simultaneous with the first, a concave model 56 (FIG. 11) is produced, the internal shape of which is identical to the shape of the external surface of the external shell 18 of the half-frame considered. In order to obtain the offset between lines 32 and 34 in Figure 9, the depth (horizontal in Figure 11) of the model 56 is calculated so as to give an outer shell 18 whose corresponding dimension is not equal ( it is higher in the case of the half-frame shown, but would be lower for the other half-frame) than that of the inner shell 16 already obtained.

 The concave model 56 is fixed by its periphery to a support 57, using screws 53. By proceeding as above, a layer of polyester resin is formed on the interior surface of the model 56 which provides, after solidification, the external shell. demouldable 18.

 In a third step (see FIG. 12), after having dismantled the models 5i, 56 from their supports 52 and, respectively, 57, one proceeds to the simultaneous mounting of these models, still carrying the shells i6 and 18, on a common support 59 to which they are fixed by screws 53.

 The above assembly must respect the mutual centering of the two models 51, 56, which can moreover be obtained simply by correct positioning of the screws 53 or by these mutual centering conformations of the two models. This results in an equal spacing of the inner and outer shells in the regions of the floor and of the carriage tray, and consequently an identical thickness of intermediate synthetic foam 30 in these regions. The thickness of the peripheral part of the base of the model 51, by which the latter is fixed to the support 59, determines a suitable distance between the central parts of the shells 16 and i8. These various mutual positions of the models correspond to mutual contact of the shells 16 and 18 along the edges corresponding to the lips 80. These regions of mutual contact were filled with an adhesive prior to the assembly of the two models, so that said assembly produces a collage of the two shells.

 Next, synthetic foam is injected between the two shells 16 and 18 by means of an injector comprising a spout 64 preferably arranged at a low point in the system of the shells. Under these conditions, the degassing is easily carried out at the upper part of the device by means of suitable orifices or interstices not shown.

 The different phases of the above process are applicable to the production of the half-frame 10 as well as to that of the half-frame 20. However, special measures must be taken in the case of the frame 10 to fix the four hinges 11 to it.

 To securely fasten the hinges to the vertical wall 4 of the half-frame 10, one can proceed as follows (see Figures 14 and 15). A rigid support 61, for example made of steel, is fixed by screws 63 along each edge of the model 56 corresponding to a vertical edge of the half-frame 10. The support 61 is intended to position the parts of hinges which must be rendered integral with the wall of the frame during the phase of making the half-frame 10 from the two corresponding half-shells 16, 18.

 The support 61 comprises two recesses 65, intended to receive and axially position each a hinge body 11, constituted by the three cylindrical housings 38, lesqueis are integral with the hinge formed by the plates 35, 39. The two recesses 65 are arranged in alignment so that the two hinge bodies can have their coaxial cylindrical housings and that there can be slidably engaged therein a rod 67 forming a common axis passing through the support 61 and thus ensuring the radiated positioning of the hinge bodies, the corresponding hinges being placed on the future internal face of the outer shell 18. It is convenient for this to place the model 56 so that the part of the outer shell 18, which is intended to be part of the side wall 4 of this half-frame , or placed horizontally above the model 56, the future internal face therefore facing upwards. Under these conditions, the perforated plate 39 is automatically offset with respect to the outer shell 18 by a distance equal to the thickness of the plate 35 which rests on the shell 18.

 Then, as already described, the convex model 51 is placed in the model 56 cavity (see FIG. 12) so that the glued edges corresponding to the lips 80 come one on top of the other. In addition, the model 51 defines for the shell 16, in the region of the hinge 11, a bulge (see FIG. 15) which allows it to also be applied to the plate 35 of the hinge hinge. By way of example, the width of the perimeter strip according to which the two shells apply to one another can be approximately one centimeter.

 We then rotate the two assembled models so that the future half-floor and half of the half-frame are in a horizontal plane and we proceed to the injection of synthetic foam.

 After solidification of the intermediate synthetic foam, the models 51, 56 are separated and the half-shells 16, 18 are extracted, which form a single piece constituting the half-frame 10 provided with its four parts of hinges 11 .

 The half-frame 20 is produced by a method analogous to the method described above, but in which the step of fitting the hinges is omitted, and the model on which the inner half-shell 26 is formed is adapted accordingly. , since there is no longer any need to provide for the latter a bulge in the region of the hinges. On the other hand, a recess must be provided in the region of the opening for fixing the keeper 29 of the lock 25. As a variant, the keeper 29 can be fixed in a manner analogous to the method of fixing the hinges by suitable positioning. using appropriate means relative to one of the two models, then pinching between the two shells of an anchor secured to this keeper.

 When making the two half-frames 10, 20, a certain number of recesses must be made for the insertion of inserts, such as stops 45 for the meal trays 19, or for the fixing of the supports 12 of casters 14.

 Each of the doors 6 is produced by a similar process (see FIG. 16) using a planar model 71 and a concave model 73 against which the outer skins 24 are formed (with the laying of magnets 82 between two successive layers of impregnated glass wool , as described for wall 4) and, respectively, interior 22 of door 6.

 For the assembly of the two skins 22, 24, a steel support 75 is used which is fixed to the planar model 71 by means of screws 63, and which has a shoulder 74 against which an edge of the concave model can bear. 73 for the mutual positioning of the two skins. The support 75 comprises two aligned recesses 76 each of which receives and axially positions the body with two cylindrical housings 36 of a hinge 11, these two housings being integral with the hinge formed by the plates 35, 39.

The plate 35 being pressed against the internal face, turned upwards at this stage, of the external skin 24, the perforated plate 39 is spaced from the two skins to then be trapped in the foam which will be injected between the two skins to ensure anchoring of the hinge. On the plate 35, on the inner side, is supported the peripheral edge of the inner half-shell 22, this edge having a bulge at the right of each hinge according to an arrangement similar to that already described in the case of the half-frame 10 (figure 15). A common axis 77 crossing the pairs of cylindrical housings of the two hinges positions these two hinges radially. We then proceed to assemble the two models, with simultaneous bonding of the peripheral edges of the two shells, and to the injection of synthetic foam as before.

 The plate 35 of the hinges integral with the door 6 has from the corresponding edge of the door towards the body of the hinge a camber 135 towards the outside of the frame when the door is in the closed position (FIG. 7, position in solid line) . Thus, the door 6 fits into the lip 80 although the body of the hinge is outside of the lip 80. In addition, when the door is open (position in phantom) it is pressed against the half shell 18 although the body of the hinge practically does not project relative to the half-shell 18, which is important for the movement of the carriage in the corridors and aisles.

 It was not considered useful to represent in detail the region of the door 6 in which a recess forming a handle 31 is made (see FIG. 3). It suffices in fact, according to a well-known technique, to provide in the planar model 71 a protuberance giving on the outer skin 24 a recess and, in the concave model 73, a hollow of conjugate profile giving the inner skin 22 a contouring shape the recess of the skin 24.

 The skins 16, 18, 22, 24, 26, 28 can have a thickness of 1.5 mm, the free space between them for the resin being of the order of 10 mm.

 The trolley according to the invention is robust, light and economical to produce. It is very resistant to deformation and scratches, as well as to aging and fatigue. In addition, it is very easy to clean effectively with a pressure jet.

Claims (22)

 1. Trolley for catering (1), in particular in rail, air or sea transport, comprising a structure in the general shape of a parallelepiped comprising fixed walls (3, 4, 5, 7), and two pivoting walls for use door (6) in two opposite side faces of the parallelepiped, characterized in that at least some of said walls are part of a set of double skin walls (3, 4, 5, 7; 6) comprising an inner skin (16 , 22) and an outer skin (18, 24) both made of relatively rigid resin and, between these two skins, a filling of synthetic foam (30) ensuring a connection between the two skins (16, 22; 18, 24).  2. Trolley according to ia claim 1, characterized in that the skins (16, 18; 22, 24) are adjacent to each other along at least some of the edges (80) of the double skin walls.  3. Trolley according to claim 1, characterized in that the skins (16, 18; 22, 24) are applied flat against each other along at least some (80) of the edges of the double skin walls .  4. Trolley according to one of claims i to 3, characterized in that the outer skin (18, 24, 28) of each double skin wall has a substantially rectilinear profile, while the inner skin (16, 22, 26 ) of each double skin wall has, from at least some of the edges, a profile bent in the direction opposite to the outer skin and then bent substantially parallel to the outer skin.  5. Trolley according to claim 1, in which the set of walls made with two skins comprises the set of fixed walls (3, 4, 5, 7), characterized in that the fixed walls belong to two half-frames (10, 20) each of which comprises, as an interior half-skin, a one-piece interior half-shell (16, 26) and as an exterior half-skin a one-piece exterior half-shell (18, 28), these two half-frames being connected l to one another along two junction surfaces (32, 34, 103) extending from one opening of the frame to the other.  6. Trolley according to claim 5, characterized in that the two connection surfaces extend one in a floor (5) of the trolley, the other in a table (7) of the trolley, in the vicinity of the longitudinal plane center (P) of the carriage.  7. Trolley according to one of claims 5 or 6, characterized in that along each junction surface (32, 34, 103), adjacent edges (32) of the interior demicoques (16, 26) are offset by relative to adjacent edges (34) of the outer half-shells (18, 28).  8. Trolley according to one of claims 5 to 7, characterized in that the edges of the two half-cuckold (16, 26; 18, 28) of each half-frame are applied flat against one another along the periphery of each opening to form around the opening a peripheral lip (80) into which fits the corresponding door (6) in the closed position.  9. Trolley according to one of claims 5 to 8, characterized in that each door (6) is applied, in its closed position, against a shoulder (316) of the inner half-shells.  10. Trolley according to one of claims 1 to 9, characterized in that a striker (29) is embedded between the two skins of a double skin wall (3) in the vicinity of each opening, for a lock ( 25) fixed to the corresponding door (6).  11. Trolley according to one of claims 1 to 10, characterized in that the set of walls made with two skins comprises all of the pivoting walls for door use (5).  12. Trolley according to one of claims 1 to 7, 9 and 10, characterized in that the set of walls made with two skins comprises the set of pivoting walls for door use, and in that, in its closed position, each door (6) is fitted into a corresponding opening in the carriage frame.  13. Trolley according to claim 12, characterized in that each door (6), when it is fitted into the frame in the closed position, joint shape due to the fitting.  14. Trolley according to one of claims 11 to 13, characterized in that each door has, in its outer skin (24), a recess (31) forming an integrated handle for carrying the trolley.  15. Trolley according to one of claims 1 to 11, wherein the doors (6) pivot around hinges (11), characterized in that each of the hinges is connected to at least one double-skin wall (4, 6 ) and in that each hinge (11) comprises, for its connection with said wall a hinge (35, 39) caught between the two skins (16, 18; 22, 2 =) of the wall and in the synthetic foam (30 ) connecting the two skins.  16. Trolley according to claim 15, characterized in that said hinge hinge (11, has several perforations (40) in which the synthetic foam (30) can penetrate when filling the gap between the two skins and thus strengthen , after solidification, the fixing of the hinge.  17. Trolley according to one of claims 15 or 16, characterized in that a part (39) of said hinge is offset so as to provide two intervals between this offset part and each of the two skins (16, 18; 22, 24), so that synthetic foam (30) can penetrate on either side of the hinge during the filling operation with synthetic foam.  18. Trolley according to one of claims 15 to 17, characterized in that the double skin wall is a wall for door use, and in that the hinge has from the corresponding edge of the door to the hinge a part arched towards the outside of the frame when the door is in the closed position.  19. Trolley according to one of claims 1 to 14, characterized in that the set of walls (3, 4, 5, 7; 6) with double skin comprises the set of fixed walls and the set of walls swivel for door use.  20. Trolley according to one of claims 1 to 19, characterized in that magnetic means (82) are embedded in at least one of the double-skin walls to detachably hold, by attraction of conjugated magnetic means, the doors in a fully open position, in the laqueile they are folded against a side wall (4) of the frame.  21. Method for producing a wall provided with a hinge, in the context of the manufacture of a catering trolley according to one of claims 1 to 20, characterized in that an inner skin is produced (16, 22 ) and an outer skin (18, 24) on respective models (51, 56, 71, 73), a hinge (35, 39) of hinge by positioning a body (36) of the hinge in a recess (65, 76) linked to the model of the first skin, in order to position the body of the hinge axially, the body of the hinge is made to cooperate with a radial positioning means (67, 77), the two models are assembled so that the two skins have the desired position relative to each other to form the wall, then foam is injected (30) between the two skins.  22. Method according to claim 21, characterized in that at least one perforated part (39) of the hinge is placed at a distance from said inner face so that the foam (30) comes into contact with the two faces of the perforated part (39) and occupies the perforations (40).