FR2963322A1 - Automatic leak-proof sealing device for plastic food product tray, has guiding units cooperating with complementary guiding units of parts to guide displacement of plate in translation, with edges during positioning and withdrawal of plate - Google Patents

Abstract

The device has a support plate (6) comprising parallel longitudinal edges (61) provided with guiding units such as guiding plate (64) and cylindrical contact plate (65). The units cooperate with complementary guiding units e.g. outer surface (221b) and longitudinal guiding groove (24), of plane longitudinal parts (221) of a tubular lateral wall (22) of a parallelepiped lower cover (2) to guide displacement of the plate in longitudinal translation, with the edges during positioning and withdrawal of the plate on and from a side of a plane front transversal part (222a) of the cover.

Description

The present invention relates to a device for tight sealing of containers, in particular plastic trays, for sealing by thermal welding a film on a lidding rim of said containers, in particular for packaging under vacuum or in a modified atmosphere of foodstuffs. The invention more particularly relates to a sealing device with a support plate change system for adapting the device to different sizes of containers. It is known, particularly in the patent document FR 2 928 626 filed by the applicant company, sealing devices comprising an enclosure comprising at least one upper bell and one lower bell able to be displaced vertically relative to the other by a first displacement system between an open position for the passage of the film and a closed position for the welding operations, a support plate removably mounted on the lower bell and provided with one or more openings for supporting one or more containers by their rim, and a welding head mounted vertically movable in the upper bell. The welding head conventionally comprises a soleplate carrying one or more welding plates, a cutting blade associated with each weld plate, and one or more heating blocks for heating the welding plates. A second displacement system vertically displaces the solder head between a retracted position and an active position in which each solder plate welds the film to the rim of a container and the associated blade cuts the film around the rim. Each bell can be connected to a vacuum pump to achieve vacuum sealing, an inert gas can be further injected via the lower bell just before the welding operation to achieve lidding under modified atmosphere.

The support plate and the welding head have complementary shapes and are adapted to the format of the containers to be sealed. Different interchangeable sets of support plate and welding heads can be mounted on the bells depending on the size of the containers to be sealed.

In the aforementioned patent document, the lower bell is slidably mounted horizontally on the frame of the device, in the manner of a drawer, between a loading position and a position in which the lower bell is below the upper bell. The first displacement system allows to move vertically said lower bell to bring the bells in their closed position or their open position. For the establishment of a support plate, the lower bell is brought into the loading position. The support plate is placed on the upper edge of the bell, its maintenance being ensured by lower pads of the plate being housed in complementary housing of the lower bell. The lower bell can also be used for changing the welding head. The position of the operator for the removal and placement of a support plate or welding head from above the lower bell is poorly ergonomic. Moreover, such a lower bell system, which is mounted in a drawer for the change of the support plate, and which must also be movable vertically to form a sealed enclosure, is complicated to achieve. The object of the present invention is to provide a sealing device 20 overcoming at least one of the aforementioned drawbacks, which can be adapted quickly and easily to various sizes of containers to be sealed. For this purpose, the subject of the present invention is a device for tight sealing under a film of containers, for example of the plastic container, by thermo-welding a film on a sealing rim of said containers, in particular with a view to vacuum or modified atmosphere packaging of food products, which device comprises at least one upper and one lower bell that can be moved vertically relative to each other by a first displacement system between a position open for the passage of the film and a closed position to form a chamber, the lower bell comprising a bottom wall and a tubular side wall, said side wall having two opposite longitudinal parts,

3 parallel, substantially flat, interconnected by two opposite transverse portions, - at least one support plate adapted to be removably mounted on the lower bell in a mounted position, provided with one or more openings for receiving containers and supported by their rim, the support plate comprising two substantially parallel opposite longitudinal edges and two lateral edges, - a welding head mounted vertically in the upper bell, comprising a soleplate carrying one or more welding plates, and - and preferably a second displacement system capable of vertically displacing the welding head between a retracted position and a welding position in which each solder plate welds the film on the sealing lip of a container, characterized in that the edges longitudinal members of said support plate are provided with guide means adapted to cooperate with means complementary guide means of the longitudinal parts of the side wall of the lower bell to guide the displacement of the support plate in longitudinal translation, with the longitudinal edges of the support plate substantially parallel to the longitudinal parts, during the introduction and the removing the support plate from the side of one of the transverse portions of the lower bell. According to the invention, the support plate can be installed by a lateral side of the lower bell, without moving this behind. To do this, guiding means are provided to guide the longitudinal displacement of the support plate for its introduction and withdrawal from one side of the lower bell. According to one feature, said support plate comprises longitudinal locking means adapted to cooperate with complementary longitudinal locking means of the lower bell for locking longitudinally in at least one longitudinal direction the support plate in position mounted on the lower bell. According to another feature, said support plate comprises vertical locking means capable of cooperating with locking means

4 vertically complementary to the lower bell to vertically block the support plate on the lower bell when the support plate is in the mounted position. According to one embodiment, said guide means comprise a guide plate mounted along each longitudinal edge, preferably over substantially the entire length of said longitudinal edge, and extending perpendicularly beyond the lower surface of the support plate. said complementary guide means comprising the outer surfaces of the longitudinal parts of the bell against which said guide plates come, the support plate resting in the mounted position on the upper edge of the side wall of the lower bell. According to one embodiment, a first element among the inner surface of at least one of the guide plates and the outer surface of at least one of the longitudinal parts is provided with at least one protruding stud, said second element comprising a longitudinal guiding groove in which said pad is slidable, the support plate being slidably mounted horizontally on the lower bell, said pads and grooves constituting guide means, said pads constituting vertical locking means. According to one embodiment, each guiding groove extends to a first end of said surface in which it is formed, to allow engagement and removal of the stud, and is preferably interrupted before the second end of said surface to form a stopper to the pad in the mounted position, said pad and said stop constituting longitudinal locking means. According to one embodiment, each guide plate is provided with at least one stud, disposed on its inner surface, adapted to slide in a longitudinal groove formed on the outer surface of a longitudinal portion. According to one embodiment, at least one of the two transverse portions of the lateral wall has a transversely movable locking rod, substantially perpendicular to the longitudinal portions, between an extended position in which said rod is able to fit into a hole of one of the guide plates when the support plate is in its mounted position, in order to lock at least longitudinally and preferably also vertically, said support plate on the lower bell, and a retracted position in which said rod is discarded said hole to allow the removal of the support plate, said rod being preferably biased elastically towards its deployed position. The locking rod constitutes longitudinal locking means and transverse locking. According to one embodiment, at least one of the support plate and the upper edge of the lower bell is provided with a seal, and / or said groove has a final portion, on the side of the second end of the longitudinal portion, away from the longitudinal edge so as to press the support plate against the upper edge to ensure sealing.

According to one embodiment, the device comprises a frame on which the lower bell is mounted vertically movable by means of the first displacement system. According to another feature, the device comprises a barrel rotatably mounted on the frame of the device about an axis of rotation, vertical or horizontal, preferably horizontal, carrying at least two upper bells, each equipped with a welding head, said barrel being adapted to be rotated to position one of the upper bells vis-à-vis, above the lower bell, in a service position. Such a barrel-type solder head change system, combined with the previously described carrier plate changing system, makes it possible to provide a lidding device that is easily and quickly adaptable to different tray sizes. The invention will be better understood, and other objects, details, features and advantages will become more clearly apparent from the following detailed explanatory description of a particular presently preferred embodiment of the invention, with reference to the schematic drawings. attached, in which: - Figure 1 is a schematic perspective view of a sealing device according to the invention; Figure 2 is a schematic view in longitudinal section of the device of Figure 1; FIG. 3 is a perspective view of the lower bell and a support plate of the device of FIGS. 1 and 2, before the mounting of said support plate on the lower bell; FIG. 4 is an enlarged view of detail D of FIG. 1, illustrating the blocking rod of the support plate on the lower bell; FIG. 5 is an enlarged perspective view of the cylinder equipped with upper bells and a plate; support, in the closed position 10 of an upper bell and the lower bell; and FIG. 6 is a sectional view along section plane VI-VI of FIG. 5. The sealing device shown in these figures is of automatic type and is intended for vacuum or atmosphere packaging. modified food products contained in plastic trays B, the lidding being made by means of a plastic film. The sealing device according to the invention can also be semi-automatic type, and / or be used for sealing various containers, including aluminum containers, glass or ceramic for example. Referring to Figures 1 and 2, the device comprises several upper bells la, lb, 1c, 1d, assembled on a cylinder 4 which is rotatably mounted on the frame 3 about an axis A of horizontal rotation, and a single bell 2 lower mounted vertically movable on said frame. Each upper bell brought into a service position by rotation of the barrel is adapted to form with the lower bell a chamber, said vacuum. Referring in particular to Figure 3, the lower bell 2 is generally parallelepipedal shape. It comprises a flat bottom wall 21, and a tubular side wall 22 extending from the bottom wall and having an annular upper edge 23. This side wall is formed of two opposite longitudinal parallel parts 221, substantially planar, interconnected by two opposite transverse portions 222a, 222b, substantially planar, parallel to each other. In

7 reference to Figure 2, the lower bell is mounted on the frame 3, below the cylinder 4, under the bell the top of the cylinder which is in the service position. A first displacement system, such as pneumatic cylinders 5, vertically displaces the lower bell 2 in vertical translation to bring the bells in the open position, as shown in Figure 3, or in the closed position for welding operations . The upper bell receives on its upper edge 23 a bezel or support plate 6, able to support one or more trays by their edge. The support plate 6 is substantially rectangular, and comprises two parallel longitudinal edges 61 and two parallel lateral edges 62. It is provided with one or more through openings 63, of which there are two in the present embodiment, whose shape corresponds to the shape of the trays to be sealed. The side wall 630 defining each opening has a shoulder 631 serving as a support surface for the trays edges. The shoulder is provided with an annular groove 632 for receiving the cutting blades, as described below. The placing of the support plate on the lower bell and its withdrawal are carried laterally. For this assembly / disassembly, the support plate 6 comprises along each longitudinal edge 61 a guide plate 64, extending perpendicularly beyond the lower surface 6a of the support plate. Each guide plate is provided on its inner surface 64a with a substantially cylindrical stud 65, close to its rear end. Each stud is intended to slide in a longitudinal guiding groove 24 formed on the outer surface 221b of a longitudinal portion 221. Each groove extends parallel to and near the upper edge 23, from an edge 221c, said front, of said longitudinal portion 221, and stops before the second rear edge 221d. For the mounting of the support plate, the pads 65 are inserted into the grooves 24 of the guide, by the front end portions 241 of the grooves which open on the front edge 221c, the support plate resting by its lower surface 6a on the edge 23 higher. Then, the support plate is slid, substantially

8 horizontally on the top edge 23. The guiding plates 64 disposed against the outer surface 221b of the longitudinal portions 221 and the studs placed in the guide grooves 24 guide the longitudinal displacement of the support plate in the longitudinal direction D1. The support plate is positioned correctly on the upper edge, in a so-called mounted position, when the pads 65 come into abutment against the rear walls 242 of the grooves 24. To facilitate engagement of the pads 65 in the guide grooves 24, the latter have portions 241 before flared, with a large cross section, which gradually decreases towards the rear wall 242 of the grooves. The upper edge 23 is provided with a seal. Each groove 24 has a rear portion 243, also called final portion, deviating from the upper edge so as to press the support plate against the seal. Referring to Figure 4, a locking rod 26 is movably mounted in a recess on the outer surface of the front transverse portion 222a. The rod is mounted mobile horizontally and parallel to the front transverse part, by means of a support 27 comprising two tubes 271, 272, transversely offset, in which the rod 26 passes. The rod is elastically biased, via a spring 28, into an extended position illustrated in Figure 4, wherein said rod has an active end 261, which protrudes from the outer surface of one of the longitudinal portions, and which engages in a hole 66 of the one of the guide plates 64, when the latter is in its mounted position. The other end of the rod, disposed beyond the tube 272, is equipped with an actuating lug 262 for pulling the rod to the right in FIG. 4, against the spring, and bringing it into position. a retracted position in which said rod is spaced from said hole to allow removal of the support plate. As illustrated in Figure 1, the lower bell 2 is placed in a protective cowling 31, this cowling comprising a side door 32 to access the lower bell.

Referring to Figures 5 and 6, the barrel 4 comprises a frame 40 of generally parallelepiped shape, comprising two flanges 41 square side, interconnected at the corners by four cross members 42. The barrel is rotatably mounted on the frame by its flanges, a motor 44 ensuring its rotation. An upper bell la, lb, 1c, 1d is mounted on each of the four faces of the barrel. Each upper bell comprises a bottom wall 11, through which the bell is fixed to two crosspieces of the barrel, and a tubular lateral wall 12 of rectangular section. Each bell is equipped with a welding head 7 mounted movably by means of two welding jacks 43, whose cylinders 431 are assembled on the inner face of the bottom wall 11, and whose piston rods 432. pass through the bottom wall in a sealed manner. The welding head comprises, in a manner known per se, a soleplate 71, through which the head is mounted at the free ends of the piston rods 432. The sole plate - one or more welding plates 72, two in the illustrated embodiment, each comprising an edge 721 of annular welding shaped to come to bear on the sealing lip of a tray, 20 - a cutting blade 73 associated with each weld plate, forming a closed loop around the annular welding edge of the weld plate, and one or more heating blocks 74 for heating the weld plates. A counterplate 75, provided with an opening 751 for the passage of each welding plate 72 associated with a blade, is mounted on the annular free edge 12a of the bell. The counter plate is provided on its underside with a seal surrounding each opening 751. The blades are attached to the sole. Each solder plate is mounted on a heating block. Each weld plate is mounted movably on the soleplate, via its heating block, and is biased by elastic return means to a rest position in which the cutting blade 73 is set back relative to the edge 721 of welding. The welding jacks 43 make it possible to move the welding head between a so-called

i0 retracted in which the welding plates are recessed relative to the underside of said counterplate. The upper bells are equipped with different solder heads to quickly adapt the device to different tray sizes. The motor makes it possible to rotate the barrel about its axis A in order to bring the desired welding head, substantially horizontally, vis-à-vis the lower bell, a so-called service position. The upper bells and the lower bell are each equipped, in a manner known per se, with connection means to a vacuum pump for evacuation. The lower bell further comprises means for connection to a source of gas to be injected, in particular inert gas, for injection into the gas containers, in particular inert gas, after evacuation and before sealing. The plastic film which is to be used for the lidding passes between the lower bell and the upper bell in the service position. The film comes from a coil 91 and is engaged on guide rollers. The skeleton emerging from the two bells is retrieved on a second spool 92 positively rotated by a motor, passing through a guide roll. The coils 91, 92 are mounted on the axes of the frame arranged parallel to the axis of rotation A of the barrel. The device furthermore comprises a conveyor 8 with a step-like step for bringing trays between the two bells in their open position. Referring to Figure 3, the lower bell 25 is equipped with one or more ejector plates 29 vertically movable by cylinders (not shown) to lift the trays out of the openings 63 after sealing to allow their removal via the conveyor . The description of the operation of the device will now be performed. The barrel 4 is rotated to bring into service position the welding head 7 which is adapted to tray sizes B to be sealed. The corresponding support plate 6 is placed on the lower bell. To do this, the lateral door 32 is open to access the

It is upper bell, the actuating tab 262 is pulled to the right to disengage the rod 26 of the hole 66 of the installed support plate. The support plate can then be removed by moving it in the direction D2. The appropriate support plate is then slid on the lower bell by introducing the studs 65 into the guide grooves 24, while maintaining the rod 26 in the retracted position. The support plate is pushed in the direction D1, until the abutment of the studs against the rear walls 242 of the grooves, and the engagement of the rod 26 in the hole 66.

The lidding cycle is as follows. When the tray or trays arrive above the support plate 6, with the trays 29 ejectors high position, the latter are lowered in the retracted position, so that each tray B rests by its rim on the shoulder 631 of a opening 63, then the lower bell 2 is raised by the cylinders 5, to bring the bells 2 and the closed position. In this closed position, the support plate 6 comes against the plate against 75, as shown in Figure 6. Before this passage in the closed position, a new portion of film has been brought between the two bells by driving the coil 92. The welding head is then moved downwards, via the jacks 43, from its retracted position of FIG. 6 to a welding position in which the annular edge 721 of each welding plate 72 welds the film onto the edge of a tray B, and the associated blade 73 cut the film around said flange. In this welding position, the blades 73 are housed in the grooves 632.

The welding cylinder 43 is then controlled to return the head to the retracted position, and the bells are returned to the open position by the cylinder 5. The ejector plates 29 are moved upwards in the high position to remove the trays trapped, via the cleats of the conveyor 8, and to receive other trays to seal.

Although the invention has been described in connection with a particular embodiment, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention.

Claims (11)

REVENDICATIONS1. Container tight sealing device (B), by thermofusion of a film on a sealing lip of said containers, comprising - at least one upper bell (la, 1b, 1c, 1d) and a bell lower part (2) capable of being displaced vertically relative to each other by a first system (5) for moving between an open position and a closed position to form an enclosure, the lower chamber comprising a wall (21) base and a tubular lateral wall (22), said lateral wall comprising two parallel, substantially plane, opposite longitudinal portions (221) interconnected by two opposite transverse portions (222a, 222b), - at least one plate (6) support adapted to be removably mounted on the lower bell (2) in an assembled position, provided with one or more openings (63) for receiving containers and supporting them by their flange, the support plate comprising two edges (61 ) longi substantially parallel opposed panels and two lateral edges (62), 20 - a welding head (7) mounted vertically movable in the upper bell, and - a second displacement system (43) able to vertically move the welding head between a position retracted and a welding position, characterized in that the longitudinal edges (61) of said support plate (6) are provided with guide means (64, 65) able to cooperate with complementary guide means (221b, 24). longitudinal portions (221) of the lateral wall (22) of the lower bell (2) for guiding the displacement of the support plate (6) in longitudinal translation, with the longitudinal edges of the support plate 30 substantially parallel to the longitudinal portions, when placing and removing the support plate on the side of one (222a) of the transverse portions of the lower bell. 2. Device according to claim 1, characterized in that said plate (6) support comprises means (65, 66) of longitudinal locking 35 adapted to cooperate with means (243, 26) for locking 13 longitudinal complementary to the bell ( 2) to lock longitudinally in at least one longitudinal direction (D1, D2) the support plate in the mounted position on the lower bell. 3. Device according to claim 1 or 2, characterized in that said support plate comprises means (65, 66) for vertical locking capable of cooperating with means (243, 26) vertical locking complementary to the bell (2) below for vertically locking the support plate on the lower bell when the support plate is in the mounted position. 4. Device according to one of claims 1 to 3, characterized in that said guide means comprise a guide plate (64) mounted along each longitudinal edge (61), and extending perpendicularly beyond the lower surface (6a) of the support plate, said complementary guide means comprising the outer surfaces (221b) of the longitudinal portions (221) of the bell against which said guide plates come, the support plate (6) resting in the mounted position on the upper edge (23) of the side wall of the lower bell. 5. Device according to claim 4, characterized in that a first element among the inner surface (64a) of at least one of the guide plates (64) and the outer surface (221b) of at least one of one of the longitudinal portions (221) is provided with at least one projecting stud (65), said second element comprising a longitudinal guiding groove (24) in which said stud is slidable. 6. Device according to claim 5, characterized in that each guide groove (24) extends to a first end of said surface (221b), to allow engagement and removal of the stud (65), and stops before the second end of said surface to form an abutment to the stud in the mounted position. 7. Device according to claim 5 or 6, characterized in that each plate (64) for guiding is provided with at least one stud (65) disposed on its inner surface (64a), able to slide in a groove (24). ) longitudinal formed on the outer surface (221b) of a portion (221) longitudinal. 14 8. Device according to claim 6 or 7, characterized in that at least one of the two portions (222a, 222b) transverse of the wall (22) side has a locking rod (26) mounted movably between a position deployed in which said rod is adapted to fit into a hole (66) of one of the guide plates (64) when the support plate is in its mounted position, in order to lock longitudinally and vertically, said plate (6) support on the lower bell (2), and a retracted position in which said rod is spaced from said hole to allow removal of the support plate. 9. Device according to one of claims 5 to 8, characterized in that at least one of the plate (6) support and the edge (23) of the upper bell (2) is provided with lower a sealing gasket (25), said groove (24) having a final portion (243), deviating from the longitudinal edge (23) so as to press the support plate against the upper edge. 10. Device according to one of claims 1 to 9, characterized in that it comprises a frame (3) on which the lower bell (2) is mounted vertically movable through the first system (5) of displacement. 11. Device according to one of claims 1 to 10, characterized in that it comprises a cylinder (4) rotatably mounted on the frame (3) of the device about an axis (A) of rotation, carrying at least two bells (la, lb, 1c, 1d) upper, each equipped with a head (7) of welding, said cylinder being adapted to be rotated to position one of the upper bells vis-à-vis, above of the lower bell, in a service position.