WO1997021591A1

WO1997021591A1 - Method for placing lids onto containers and apparatus therefor

Info

Publication number: WO1997021591A1
Application number: PCT/EP1996/005378
Authority: WO
Inventors: Marc Michiel Olthoff; Cornelis Leonardus De Vries
Original assignee: Unilever N.V.; Unilever Plc
Priority date: 1995-12-08
Filing date: 1996-11-28
Publication date: 1997-06-19
Also published as: ZA9610236B; AU1097897A

Abstract

Method for placing a lid (4) onto a container (5) and apparatus therefor, the method comprising the movement of a container having a rim (6) at the opening of it, a lid being provided by a supply means (2) being positioned so that the rim (7) (at the side of the lid pointing downwards) can touch the rim of the container (at the side of the container pointing forwards), the lid being positioned by a pusher bar (3) to allow the rims to grip, the pusher bar providing forces onto the lid to maintain the gripping of the rims of said lid and said container while the lid is released from the supply means, and the lid being positioned onto the opening of the container. The placing of the lid onto the container takes place while the container moves, and so, the method and apparatus are in particular suitable for placing lids onto containers while the containers move without intermittance of velocity or moving direction being required.

Description

Method for placing lids onto containers and apparatus therefore

The present invention concerns a method for placing lids onto moving containers, in particular for containers which have a rim around the opening, such as tubs. In another embodiment, the invention provides an apparatus for placing lids onto moving containers .

At present, a method is known for placing lids onto moving tubs in which a slip-on system is used, where the tub takes a lid that is presented. The tub rim catches the rim of the lid and takes the lid. The lids are presented vertically, and to place the lids these are bend over a large roller. This method is suited for round lids only, and allows not more than small variations in lid size. Moreover, the method is suited for round, flexible lids only.

In another method known for closing containers, the lids are presented at a slight angle with the horizon, and the container rim catches the rim of the lid and takes the lid on. As the angle at which the lids are presented iε small and the lids are usually fed by gravity, the moving force is much smaller than the gravity force on the lid. This results in the method operating at low maximum speed, and being unreliable. In addition thereto, the length of the apparatus needed for the method is relatively long as its length is at least the length of two lids. The lid falls onto the container by gravity, and is found not to be always reliable.

In yet another method known for placing lids on containers as described in US patent no. 4,691,501, the method does not provide for a very reliable system, as the positioning of the lids onto the containers to be closed is not very reliable, in particular at high speed operation, the direction of falling of the lids is not allways as accurate as needed for reliable operation, which in turn means it may even be needed that the process is stopped.

The present invention provides a method by which these drawbacks have been overcome, the method comprising the continuous movement of a container having a rim at the opening of it, a lid being provided by a supply means, the lid being positioned so that its rim (at the side of the lid pointing downwards) can touch the rim of the container (at the side of the container pointing forwards) , the lid being positioned by a pusher bar to allow the rims to grip, the pusher bar providing forces onto the lid to maintain the gripping of the rims of said lid and said container while the lid is released from the supply means, the lid being positioned onto the opening of the container, and the lid being forced onto the container by forces applied by the pusher bar.

It is further prefered that the pusher bar is in contact with the lid while the lid is released from the supply means, as better accuracy of the position of the lid while falling is obtained. It particular, it was found that a system not having a pusher bar providing forces onto the lid to maintain gripping of the rims is not very reliable.

The method is in particularly suitable for placing lids onto tubs, e.g. as being used for food products, such as spreads, sauces, spreadable cheese, and the like. However, as the method does not require any flexing of the lid, it is suitable for placing lids onto any type and shape of container, and includes the placing of metal lids onto glass jars.

The method is meant to allow the placing of lids onto moving containers, and is in particular suited for continuously moving containers. However, the presently found method also encompasses the placing of lids onto discontinuously moving containers. In the method of the present invention, the containers move while the lids are being placed thereon. The containers can be moved forward by any suitable transport means, such as a belt, cell plates, chains, grippers or by bars pushing the container in forward direction. The moving direction of the containers, and thus the moving direction of the transport device, can be horizontal, slightly upward or slightly downwards, or any other direction desired.

The placing of the lid onto the container takes place while the container moves, and so, the method and apparatus are in particular suitable for placing lids onto containers while the containers move without intermittance of velocity or moving direction being required.

The lid is provided so that the side meant to be the upper side faces the direction the containers moves to. It can be provided at an angle of 45° with the transport means or more. To allow efficient gripping of the rims, it is preferred that the lids are provided at an angle between 80 and 100° with the direction of movement of the containers, and preferably at an angle between 85 and 95°. In a very reliable, and very little space consuming embodiment, the lids are provided at about 90°, i.e. almost or complete vertical direction with the container movement direction.

The lid is provided by a supply means, e.g., such as illustrated in fig. (1) . Such a supply means will normally comprise a storage zone (8) where a pile of lids (4) is stored, means for the individual release from the storage zone such as knives and fingers (10) , a means through which the individual lids are transported (2) , and, optionally, a holding member (11) , which prevents uncontrolled movement of the lid, although for the method of the present invention, any other type and arrangement of the supply means can be used as well. At this position, also a decontamination unit can be present for cleaning just prior to closing the containers. For the presently found method, it is desired that a holding means is present at the end of the supply transport means (9) . This holding means, which can for example be a release member (1) or a release lever, is meant to allow the release of the lid from the supply means at the correct timing. Moreover, it also can serve as a pivot point for the lid being held and placed onto the moving container. Furthermore, it allows a precise positioning of the lid, so the rim of the lid can touch the rim of the container and the lid can be taken on by the container while the container moves forward. In a preferred embodiment, the release member is found at the side of the lid which faces the container moving direction. The release member is capable of releasing the lid, for example by a forwards and backwards moving mechanism.

In a preferred embodiment of the method of the invention, the lid is released after the rim of the lid has caught the rim of the container, which in a further preferred embodiment is a tub.

The supply transport means (2) within the supply means can be any suitable means, such as sliding bars, a belt, suitably provided by grippers holding the lids in place, grippers connected to chains, and the like. The lids can be transported by the forces of gravity, and/or by mechanical forces, or any other suitable forces.

The pusher bar (3) which positions the lid so that the rims of lid and container touch is preferably a stick of irregular shape, but can also have a square, triangle, or any other kind of shape (fig. 1) . Depending on the type of lid transport and providing angle, the pusher bar is either fixed, or it is mounted to a device allowing some movement of the position of the pusher bar. In a further preferred embodiment, the pusher bar is mounted on a shaft which hinges around a pivot point . Some examples of suitable pusher bar positioning are indicated in fig. (3) . In its preferred embodiment, the pusher bar is mounted onto a device allowing horizontal and vertical movement thereof. This is in particular suitable where the containers are moved in horizontal direction, and the lids are provided by gravity at a providing angle of between 80 and 100°.

In a very preferred embodiment, the pusher bar hinges around a pivot point, and moves slightly while the container and lid are transported underneath it. While the container is moved underneath it, horizontal and vertical forces are applied onto the lid. The forces are applied in such a manner that the gripping of the rims of the lid and container iε maintained. The forces can be obtained by gravity, e.g. by using a pusher bar of sufficient weight, or by active driving (e.g. by a motor) . Slight movement of the pusher bar is highly preferred to increase reliability of placing the lids and preventing damaging of the lids, and, where desired, for closing the container. Accordingly, it is preverred that the pusher bar hinges around a pivot point.

In a highly practical manner which is in particular suitable for relatively low speed movement of the tubs use is made of gravity, whereby the pusher bar hinges around a pivot point. In another embodiment, the pusher bar hinges around a pivot point and the forces applied by the pusher bar onto the lid are adjustable by a counter weight on the other side of the pivot point. Where high capacity of closing containers is required, it is preferred that the movement of the pusher bar is actively driven, e.g. by a servo motor. The use of a hinge is preferred for its simplicity while also providing sufficient flexibility, inter alia for the size of the containers to be closed.

The pusher bar at its position where it does not touch the lid is positioned above the transport means at a suitable distance, whereby care is to be taken that the pusher bar does not hold the container when it is transported. It is preferred that the lowest part of the pusher bar is located at a distance above the surface of the transport means which will be just below the height of the container when closed. It is preferred that the distance is chosen such that sufficient forces can be applied onto the lid while lid and container are transported underneath the pusher bar, and further preferred the distance is chosen such that the pusher bar is in contact with the lid as long as possible while the container and lid move underneath the pusher bar.

In a preferred embodiment, the tubs are being moved forwards by them being pushed by bars over a smooth surface or gliding bars .

The most preferred embodiment is illustrated in fig. 3. In this embodiment, the invention is a method for placing lids on moving containers, preferably moving tubs, in which the containers (5) are moved in forward direction while a lid (4) is positioned in almost vertical direction so that the rim at the side of the lid pointing downwards (6) is at the same height as or slightly below the rim of the tub (7) moving into the direction of the lid, the tub moving forward touching the lid, the pusher bar (3) touching the lid at the moment the lid touches the tub or shortly thereafter, the lid being released from the supply means by movement of the release member (1) , the lid being forced to fall onto the tub by gravity and force from the pusher bar, and the pusher bar providing a slight force on the lid through the gravity forces applied onto the pusher bar, the pusher bar so pushing the lid onto the tub.

The present invention also concerns an apparatus for placing lids on moving containers, the apparatus comprising a horizontally moving transport means, a supply means for lids which preferably is positioned at an angle between 80 and 100° of the transport means, and a pusher bar being positioned above the transport means . In a further preferred embodiment, the apparatus also comprises a release member positioned close to the end of the supply means, and preferably at about the same distance from the transport means as the distance given for the supply means . In a further preferred embodiment, the pusher bar is a bar that can hinge around a pivot point over a small angle.

The method of the invention so provides a combination of advantages not available before. It allows a continuous movement of the containers and so the placing of lids can be part of a continuous packaging line. It provides high flexibility towards lid and tub shape and size, without significant adjustments being needed. As no flexing of the lids is required, the method is suited for all lid shapes. In particular, this means also that it can be used for lids of non-flexible material, and so allows a large choice of materials for the lids. The method was proven to by very reliable, even at high speed. Capacity of operating is very easy enhaced in the case adjustable motors are used, e.g. for driving the transport means. Moreover, the method allowed operation at a wide capacity range (from 0-1 to very high) , while reliability is maintained.

Claims

1. Method for placing a lid onto a container, the method comprising the movement of a container having a rim at the opening of it, a lid being provided by a supply means being positioned so that the rim (at the side of the lid pointing downwards) can touch the rim of the container (at the side of the container pointing forwards) , the lid being positioned by a pusher bar to allow the rims to grip, the pusher bar providing forces onto the lid to maintain the gripping of the rims of said lid and said container while the lid is released from the supply means, the lid being positioned onto the opening of the container, and the lid being forced onto the container by forces applied by the pusher bar.

2. Method according to claim 1, wherein the lid is positioned so that the angle of the lid and container moving direction is between 80-100°.

3. Method according to claim 2, in which the lid is positioned by a release member in almost vertical direction, the lid being released from the supply means by movement of the release member, and the pusher bar being in contact with the lid while the lid is released from the supply means .

4. Method according to any one of the preceding claims, wherein the pusher bar is attached to a pivot point.

5. Method according to any one of the preceding claims, wherein the container is a tub.

6. Apparatus for placing lids on moving containers, the apparatus comprising a horizontally moving transport means, a supply means for lids, and a pusher bar being positioned above the transport means.

7. Apparatus according to claim 6, wherein the apparatus comprises a release member positioned close to the end of the supply means .

8. Apparatus according to any one of claims 6 or 7, wherein the pusher bar can hinge around a pivot point over a small angle.

9. Apparatus according to any one of claims 6-8, wherein the supply means is positioned at an angle between 80 and 100° of the moving direction of the containers on the transport means .