WO2004007181A1

WO2004007181A1 - Device for applying a piece of a thin film to a container for multimedia carriers

Info

Publication number: WO2004007181A1
Application number: PCT/NL2002/000475
Authority: WO
Inventors: Yves Badts
Original assignee: YBELMECA Sarl; I-PAC TECHNOLOGIES NV
Current assignee: YBELMECA Sarl; I-PAC TECHNOLOGIES NV
Priority date: 2002-07-16
Filing date: 2002-07-16
Publication date: 2004-01-22
Anticipated expiration: 2005-01-16
Also published as: AU2002319951A8; AU2002319951A1

Abstract

A device (30) for applying a sleeve (24) of a thin film (54) to a closed container (10) for a multimedia carrier comprises a film supplying apparatus (50) for supplying a piece of film having a defined length along a film supply path (58), feed means (72) for feeding a container (10) along a container input path (62), which container input path (62) crosses the film supply path (58), a holding a container (10) partly wrapped by the piece of film, and a sealing unit (44) for sealing at least one edge (90) of said piece of film to a face (12, 16) of the container (10). The device (30) comprises a carousel (32) mounted on a driven axis (34) of rotation. The carousel (32) is provided along its periphery with a number of working stations (36), wherein each working station (36) comprises a holding unit (38) and a sealing unit (44).

Description

DEVICE FOR APPLYING A PIECE OF A THIN FILM TO A CONTAINER FOR MULTIMEDIA CARRIERS

The present invention is directed to a device for applying a sleeve of a thin film to a closed container for a multimedia carrier, comprising a film supplying apparatus for supplying a piece of film having a defined length along a film supply path, feed means for feeding a container along a container input path, which container input path crosses the film supply path, a holding unit for holding a container partly wrapped by the piece of film, and a sealing unit for sealing at least one edge of said piece of film to a face of the container. A device of this kind is known in the art of packaging multimedia containers, in particular for DVD's, CD's or videocassettes . In this technical field this device is also called a welding apparatus. Such multimedia containers usually comprise a bottom part that is adapted for holding the multimedia carrier, and a cover. This cover is hingably connected to the bottom part. Usually an empty container is covered with a plastic foil from the front face via its back to the rear face. This foil serves as a sleeve for holding an inlay, which bears e.g. printed information about the multimedia carrier. In order to allow the easy insertion of such an inlay the thin foil is sealed to the container along the edges of the front and rear faces respectively opposite to the back.

EP-B1-0 076 815 discloses inter alia a device for wrapping objects like compact cassettes, in transparent sheeting. This known device comprises a turret head, which is arranged with a horizontal axis of rotation. This turret has several U-shaped cassette holders spaced apart at uniform peripheral intervals. An apparatus for supplying transparent film so-called sheeting is disposed substantially at a tangent to this turret head. The cassettes are pushed into a cassette holder along a path that crosses the path of the transparent film and thus take along a part of the film. The cassette holders are open In radial direction and each have cooperating jaws to receive an article wrapped by the sheeting. The turret head conveys the cassettes from an insertion station, where a cassette together with a piece of sheeting is inserted in a cassette holder, to a pressing station. There the sheeting at the back of the cassette is subjected to an externally applied pressing force and sealed to the cassette. Then the thus processed cassette is conveyed in its holder to an ejection station, where the cassette is ejected onto a conveyor belt and guided past lateral pressure bars. In these known devices, the turret head has the function of a conveyor, which passes a cassette in a fixed position along the different working stations, which are arranged at positions near the periphery of the turret head. Each process step at a working station has to be completed, before the turret head can be rotated further to transfer a cassette to a subsequent working station. As a result the productivity of the known device is limited to at most 70 items per minute .

An object of the invention is to increase the productivity of a device for applying a sleeve of a thin film to a closed container. According to the invention the device for applying a sleeve of a thin film to a closed container for a multimedia carrier comprises a carousel mounted on a driven axis of rotation, wherein the carousel is provided along its periphery with a number of working stations, wherein each working station comprises a holding unit and a sealing unit.

The invention is based on the insight that the sealing step is the most significant factor which determines the total productivity of the device. Usually sealing requires the application of heat until the plasticizing temperature of the thermoplastic thin film is reached, and subsequent cooling after the sleeve is bonded to the container. In both substeps of heating and cooling the thin film piece has to be permanently pressed against the container, otherwise no durable bond would result. Thus in the known process and device, where sealing including pressing is effected by a stationary sealing unit, the total cycle time is determined substantially by the total sealing time. However, in the device according to the invention each working station comprises a sealing unit in addition to the holding unit. This means that seals between the film and the container can be brought about by the moving sealing unit during the residence time from the introduction position of the carousel, where the container has been inserted into the holding unit together with an appropriate positioned piece of film, to an ejection position. The ejection position can be anywhere around the circumference of the carousel, provided that the sealing step is finished when the container to be ejected from the holding unit arrives at the ejection position. E.g. the ejection position can be arranged 270° downstream from the introduction position. As a result the productivity can be enhanced, e.g. to about 100-110 or more containers per minute.

In a preferred embodiment the holding unit comprises an opening for introduction of a closed container, counterpressure means for forcing a part of the piece of film against the back of the container and engaging means for engagement of the top and bottom edges of the container. More preferably the introduction opening is a radial slot-shaped opening, of which the longitudinal centre line is parallel to the axis of the carousel. In order to maintain the accurate position of the piece of film with respect to the container, the counterpressures means, such as a spring-loaden counter-pusher, contacts the film part at the back of the container and maintain its relative position. Thereby sliding of the piece of film during the introduction is prevented. The container is introduced with its back first into the introduction opening, the piece of film simultaneously being pulled along. The engaging means are disposed behind the opening. In this preferred embodiment the engaging means, e.g. reciprocally movable grippers, do not restrict the actions of the sealing unit, once a container has been positioned in the holding unit. Another examples of suitable engaging means are spring-loaden parallel plates.

Advantageously the holding unit is provided with vacuum strips for stretching the respective parts of the piece of film over the front and rear faces of the container. As explained above, the container is introduced first with its back into the opening. While the position of the film is maintained by the counterpressure means at the back of the container, the vacuum strips or plates tension the other parts of the film piece over both front and rear faces of the container. Preferably the vacuum strips are positioned near the introduction opening, leaving a small gap for the sealing unit in order to allow the sealing of the edges of the film onto the container. This ensures that the seals will be applied in the same position, which improves the appearance of the final container and reduces product losses. Thus the quality of the seal and the sleeve thus obtained is improved.

According to a further preferred embodiment the container feed means comprise eccenter means for delivering a container to the holding unit, which eccenter means are rotatably mounted at both sides of the opening of the holding unit. In the known device a linear pusher mechanism is used to introduce completely a cassette into the opening of a cassette holder. This means that the pusher mechanism must have been retracted almost completely to an inactive position, before a fresh piece of film can be supplied. In other words the pusher mechanism crosses the supply path of the film twice.

Thus this pusher mechanism affects the speed of the film supply means. In the device according to the invention use is made of eccenter means which are arranged at both (preferably short) sides of the (slot shaped) opening. Because of their eccentric movement the eccenter means passes the film supply path only one time, i.e. when the container is forced into the opening and taken over by the engaging means of the holding unit. This allows starting unwinding a fresh part of thin film and positioning this in a suitable position directly after the eccenter means have passed this film supply path. Thereby the total cycle time can be decreased, and accordingly the productivity can be increased.

The sealing unit comprises preferably two welding beams, for each seal to be made one, which are pivotably arranged upon a pivot pin, preferably in parallel to the axis of the carousel. In order to allow the device according to the invention to be interchanged for containers with other dimensions, e.g. thickness, the angle between a welding beam and a container is adjustable.

In order to supply the required energy to the sealing unit in a safe and reliable manner the electricity supply to a sealing unit is via rotary sliding (brush) contacts.

Preferably the film supplying apparatus comprises endless vacuum belts for gripping the film, which are disposed above and below the container input path. In this embodiment the leading edge of the film, which film is being unwound from a stock reel or the like, is held by an upper belt and moved to the lower belt, and subsequently cut, when the required length of film has been detected and the container with associated film piece is introduced in the holding unit.

The thin film used for manufacturing the sleeve is usually mad of a thermoplastic material. Preferably the sleeve is transparent. It may be imprinted, or otherwise surface-treated.

The invention is further illustrated in the accompanying drawing, wherein:

Fig. 1 shows diagrammatically an embodiment of an open container for a multimedia carrier; Fig. 2 shows diagrammatically an embodiment of a device according to the invention; and

Fig. 3 shows diagrammatically a working station in more detail . In fig. 1 a container 10, such as a box, for a multimedia carrier like DVD, CD or videotape is shown in its open position. The container 10 has a front face 12, which is pivotably connected via its back 14 to the rear face 16. Together with the upstanding top edges 18, bottom edges 22 and side edges 26 a body is defined, delimiting a space, wherein a multimedia carrier can be positioned. A transparent sleeve 24 of a thermoplastic film is bonded at two sides parallel to the side edges 26 of the container 10 by seams 28. In the position as shown a printed inlay (not shown) can be inserted between the body of the container 10 and the transparent sleeve 24. Fig. 2 shows an embodiment of a device 30 according to the invention. The device 30 comprises a carousel 32, which is rotatable about a driven axis 34. An arrow indicates the direction of rotation. In this embodiment the carousel 32 supports eight working stations 36 at the periphery. Each working station 36 comprises a holding unit 38, which in this figure is indicated in its entirety by two parallel plates 40, a counter-pusher 41 and a radial opening 42. The counter- pusher 41 is forced outwards by means of a spring 43. Furthermore each working station comprises a sealing unit 44. In the embodiment shown the sealing unit 44 comprises welding bars 46, e.g. adapted for induction welding, which are arranged parallel to the axis 34 of rotation of the carousel 32. A welding bar 46 is connected to a linkage system 48, which will be explained in more detail hereinafter referring to fig. 3. At the left hand a thin film supplying apparatus 50 is present. This apparatus 50 comprises a stock reel 52 for a thin thermoplastic film 54. The film 54 is drawn from the stock reel 52 and guided in between rollers 56 along a film supply path 58 almost at a tangent to the periphery of the carousel 32. A container 10 is delivered e.g. by a suitable conveyor 60 along an input path 62. Vacuum belts 64 for holding and conveying the leading part of the thin film 54 are arranged above and beneath the input path 62. When a container 10 is fed into the respective working station 36, the back 14 thereof contacts the thin film 54 and a film piece having the required length is cut from the film web by cutter 66. The container 10 and this piece of film is drawn into the opening 42, while the accurate position of the film piece is maintained by the counter- pusher 41. The vacuum strips 40 positioned at a short distance from the opening 42 leaving clear a small gap, tension the respective parts of the film piece over the front face 12 and rear face 16 of the container 10. The container 10 is held in a fixed position in the holding unit 38 by the engaging grippers during the further processing steps. Once the container 10 has attained this fixed position, the carousel 32 can be rotated further to allow the introduction of another container in a subsequent working station 36. During the whole residence time of a container 10 in a holding unit 38, the sealing step can be performed. That is to say in the situation shown e.g. from introduction position A, where a container is introduced into a holding unit, to ejection position B, where a finished container is ejected, e.g. by releasing the engaging means and activating the counter-pusher 41. Fig. 3 shows diagrammatically some details of an embodiment of a working station 36. The container 10 is engaged by the hinged bars 68, which are arranged on both sides of the container 10 and can pivot about axes 70. However, for sake of clarity only one is shown. Eccenter mechanisms 72 for feeding a container through the opening 42 into the holding unit 38 are also disposed on both sides. This eccenter 72 pushes the container 10 along the container input path 62 during rotation, of which the direction is indicated by an arrow. Again only one eccenter mechanism 72 is shown for sake of clarity. The thin film 54 is held on the front and rear faces 12, 16 of the container 10 by respective vacuum strips 40 which are provided with a number of perforations at the undersidefacing the film piece. The welding bar 46 is fixedly connected to lever arms 78, which are pivotably mounted about axes 80. The other end of a lever arm 78 is pivotably connected to further rods 84, which are mounted to a mutual pivot axis 86. This pivot axis 86 can be displaced in radial direction of the carousel 32, e.g. by a cylinder 88 or preferably by a curved disc, in order to make contact between the foil 54 and container 10 at the position of a seam 28 (see fig. 2) .

Claims

C L A I M S

1. Device (30) for applying a sleeve (24) of a thin film (54) to a closed container (10) for a multimedia carrier comprises a film supplying apparatus (50) for supplying a piece of film having a defined length along a film supply path (58), feed means (72) for feeding a container (10) along a container input path (62), which container input path (62) crosses the film supply path (58), a holding unit (38) for holding a container (10) partly wrapped by the piece of film, and a sealing unit (44) for sealing at least one edge (90) of said piece of film to a face (12, 16) of the container (10) , wherein the device (30) comprises a carousel (32) mounted on a driven axis (34) of rotation, wherein the carousel (32) is provided along its periphery with a number of working stations (36) , wherein each working station (36) comprises a holding unit (38) and a sealing unit (44) .

2. Device according to claim 1, wherein the holding unit (38) comprises an opening (42) for introduction of a closed container (10) , counterpressure means (41) for forcing a part of the piece of film against the back (14) of the container (10) and engaging means (68) for engagement of the top and bottom edges (18, 22) of the container (10) .

3. Device according to claim 1 or 2, wherein the holding unit (38) is provided with vacuum strips (40) for stretching the respective parts of the piece of film over the front and rear faces (12, 16) of the container (10).

4.- Device according to one of the preceding claims, wherein the container feed means (72) comprise eccenter means (72) for delivering a container to the holding unit, which eccenter means (72) are rotatably mounted at both sides of the holding unit (38) .

5. Device according to one of the preceding claims, wherein the sealing unit (44) comprises two welding beams (46) , which are pivotably arranged upon a pivot pin (80) .

6. Device according to claim 5, wherein the angle between a welding beam (46) and a container (10) is adjustable.

7. Device according to one of the preceding claims, wherein the electricity supply to the sealing unit (44) is provided by rotary sliding contacts.

8. Device according to one of the preceding claims, wherein the film supply apparatus (50) comprises endless vacuum belts (64) for gripping the film, which are disposed above and below the container input path (62) .