WO1997029870A1

WO1997029870A1 - Seaming apparatus

Info

Publication number: WO1997029870A1
Application number: PCT/GB1997/000041
Authority: WO
Inventors: Peter Leslie Moran
Original assignee: Carnaudmetalbox Plc
Priority date: 1996-02-13
Filing date: 1997-01-09
Publication date: 1997-08-21
Also published as: GB9602890D0; GB2310156B; AU1388297A; GB2310156A

Abstract

A double seaming apparatus for seaming a can end (E) to the open end of a can body (B) is formed with a pair of annular seaming tools (3, 4) which closely surround the can end and can be moved laterally from a first position coaxial with the can end to a second position in which they engage the periphery of the can end. The can end is driven to rotate about its axis and when the can end and an annular tool are brought into engagement, they both rotate about their respective axes and roll relative to one another.

Description

SEAMING APPARATUS

The invention relates to apparatus for seaming a container end onto an open end of a container body and in particular to apparatus for seaming a can end onto the open end of a can body. Both can end and can body will normally be made of metal although they may be made of plastic or composite materials.

Typically, the seam formed by known seaming apparatus is of a type known as a double seam. During the seaming operation the seaming flange and peripheral curl of a can end are progressively folded together with a seaming flange on the open end of the can body. In conventional high speed seaming apparatus the can body is supported on a rotating lifter pad and the can end is pressed down onto the can body by a rotating seaming chuck which must be accurately aligned axially with the lifter pad.

The folding of the seam is normally carried out in two stages by two seaming rolls which are in turn brought into radial engagement with the peripheral portion of the can end.

In another known apparatus (described in US 4,808,053) the seam is formed by rolling the can end along an arcuate rail; the rail having a radius of curvature many times that of the can end.

Conventional apparatus is considered to have a number of disadvantages. Firstly the seaming rolls or rails engage the can end over a very short circumferential extent so the folding of the metal is fairly rapid and aggressive. This in turn limits the ability of current seamers to operate on can bodies and can ends formed from ultra thin steel or aluminium.

In order to improve the metal working properties of the seaming process, it has been proposed to provide apparatus in which an annular seaming tool closely surrounds the can end. Italian Patent No. 770893 describes seaming apparatus in which an annular seaming tool closely surrounds the container end and is apparently mounted for floating movement in a horizontal plane to be pressed into engagement with the can end by a roller acting on the radially external surface of the tool. It appears that the tool will thus be driven to orbit the can end. It is stated in the patent that neither the can end nor the seaming tool has axial rotation. The first part of the seaming operation is carried out by the annular tool, and the container is then transferred to another work station for the double seam to be completed.

The present invention sets out to provide an improved seaming apparatus in which an annular seaming tool closely surrounds the container end and can be moved laterally from a first position coaxial with the can end to a second position in which it engages with the can end. The can and/or the seaming tool is driven about its axis and when the two are brought into engagement they both rotate about their respective axes and roll relative to one another.

In order to improve the compactness of the apparatus, seaming is carried out by at least two annular seaming tools having at least first and second annular seaming profiles on an inner surface or surfaces and means are provided to move the seaming tools relative to the container end to enable the seaming profiles to contact the container end sequentially to perform the first and second seaming operations. according to the present invention there is provided apparatus for seaming a container end to an open end of a container body in at least first and second seaming operations: means to support the container body; a seaming chuck to support the end in place on the container body; and means for progressively folding peripheral portions of the container body and end together to form a seam; wherein the folding means comprises at least two annular seaming tools providing at least first and second annular seaming profiles on an inner surface or surfaces thereof which surround the end and wherein the apparatus includes means for moving the annular seaming tools laterally with respect to the end so as to come into engagement therewith so as to form the seam progressively, and drive means for driving the container or the seaming tool in rotation about their axes such that when the can end and an annular seaming tool are brought into engagement they both rotate about their respective axes and roll relative to one another; characterised in that there is provided means for causing relative movement between the end and the annular seaming tools, from a first relative position in which the first seaming profile can contact the end to perform the first seaming operation, to at least a second relative position in which the second seaming profile can contact the end to perform the second seaming operation.

The best metal forming characteristics are provided where the inner radius of the tools is only slightly greater than the outer radius of the can end. This is limited only by the need for clearance as the can end is located within the tools. In the case of a small container such as a beverage can, the outer diameter of the can end prior to seaming is about 60mm. The diameter of the seaming tools may need to be about 20% greater to provide the necessary clearance. In the case of larger can ends, the diameter of the tools will not need to be so much greater than that of the can end, say 5-10% in the case of a can end of 160mm diameter. In the case of a very small can end the diameter of the tools may need to be up to 50% greater than that of the can end. In a preferred embodiment, the container body is supported on a lifter pad and the chuck is driven in rotation about its axis. This transmits rotary motion to the can end, the can body and the lifter pad. The seaming tools are mounted for free rotation about their axes in carrier plates which can move in reciprocal linear motion to bring the seaming profiles into and out of engagement with the container end.

Various embodiments of the invention are described below, with reference to the accompanying drawings, in which: Figure 1 is a partial cross section through part of a seaming apparatus;

Figure 2 is a cross section through a pair of seaming tools and their carrier plates;

Figure 3 is a perspective view of a carrier plate and its associated seaming tool;

Figure 4 is a perspective view showing how the seaming tools may be mounted for operation;

Figure 5 is a horizontal cross section through further seaming apparatus; Figure 6 is a cross section of a seaming tool and its carrier plate; and

Figure 7 is a partial plan view of the seaming apparatus of Figure 5.

As shown in Figure 1, the container body in the form of a can body B is supported on a lifter pad 1. A container end in the form of a can end E is held in place on the can body by a seaming chuck 2. The chuck is driven to rotate about its axis, whilst the lifter pad is mounted for free rotation about its own axis which is aligned with that of the chuck.

The can end is surrounded by means for progressively folding peripheral portions of the can body and can end together to form a seam in the form of two annular seaming tools 3 and 4. In the embodiment shown, the seaming tools are provided by separate rings which are each mounted in a respective carrier plate 5, 6. In another embodiment (not shown) the two seaming tools may be formed integrally or as a single unit and mounted in a single carrier plate. In the position shown in Figure 1, the axes of the tools 3 and 4 are coincident with each other and with those of the seaming chuck 2, the can end, the can body and the lifter pad 1.

Upper tool 3 has a seaming profile 7 on its inner surface and is mounted for rotation in the carrier plate 5 by means of a bearing 8. Similarly, the lower tool 4 has a seaming profile 9 on its inner surface and is mounted in the carrier plate 6 by means of a further bearing 10.

A mechanism for moving the seaming tools laterally with respect to the chuck, container and lifter pad is shown in Figure 4. An arm 20 which can be turned about its axis is mounted parallel to the axis of the seaming apparatus and carries a yoke 21. Links 22 and 23 are each pivotally connected at one end to a respective free end of the yoke and are pivotally connected at their other ends to the carrier plates 5 and 6. Guideways 24 are formed in each of the carrier plates on opposite sides to enable the plates to be mounted for reciprocal horizontal linear movement on a turret (not shown) . The guideways 24 on carrier plate 6 are at right angles to the guideways on carrier plate 5.

Operation of the apparatus is as follows. A can body B is supported on the lifter pad 1 and the chuck 2, having picked up a can end E is lowered to the position shown in Figure 1 where the can end is seated on the open flanged end of the can body. In this position the upper and lower seaming tools 3, 4 are both coaxial with the can body and the profile 7 on the upper tool 3 is aligned with those parts of the can body and can end which are to be folded to form a double seam. The chuck 2 is driven to rotate about its vertical axis and this drives the can end, can body and lifter pad 1 to rotate about the same axis. In another embodiment (not shown) the lifter pad is driven and this in turn drives the can body, the can end and the chuck. The upper tool 3 is mounted for free rotation in the carrier plate 5. By rotation of the arm 20, the carrier plate 5 is moved laterally until the seaming profile 7 comes into contact with the peripheral curl of the can end to carry out the first seaming operation. This is the position shown in Figure 2. When the tool 3 engages the rotating can end, it is itself driven by friction to rotate about its own axis. This results in a relative rolling movement between the seaming tool 3 and the can end. After the first seaming operation, the arm is again rotated to return the upper tool to the position shown in Figure 1. Next, the seaming tools 3 and 4 are raised relative to the can end so that the lower seaming profile 9 is aligned with the partly formed double seam. Further rotation of arm 22 moves the lower seaming tool 4 laterally into engagement with the partly formed seam to carry out the second seaming operation. When this is completed the tool 4 is retracted and the lifter pad and chuck are moved apart to allow the can to be removed from the apparatus.

In this embodiment the can body and end are driven in rotation by means of drive to either the chuck 2 or the lifter pad 1, but the tools 4 and 5 could alternatively be driven about their axes as an alternative or in addition. Where the seaming tools are driven in rotation, the can end could be brought into and out of engagement with the tools by lateral movement of the seaming chuck and the lifter pad.

Whilst it is preferred to use two seaming tools to complete the seam in two seaming operations, more than two tools carrying out more than two seaming operations could be provided.

Figure 5 shows further apparatus for seaming a container end E onto a container body B in at least first and second operations. The apparatus comprises a base plate 30, a shaft 31, upstanding from the base plate, a turret 32 mounted for rotation around the shaft, and a motor 33 to drive the turret to rotate by means of a pinion 34 on the motor and a ring gear 35 on the turret. The turret comprises an upper plate 36, a lower plate 37, and a hollow body 38. A plurality of seaming chucks 2, are supported equispaced in the upper plate around the shaft 31 for sliding motion in a direction parallel to the shaft. Each chuck is supported in the upper plate by a spring 39 and urged to move by a cam 40 as the turret rotates around the shaft.

A plurality of lifter pads 1 are supported in the lower plate 37 in axial alignment each with a respective seaming chuck 2. Each lifter pad is moved towards and away from a respective chuck member as the turret rotates by a cam 41. Rotation of the turret 32 about the shaft 31 causes fixed ring gear 53 to drive each lifter pad so that any can on the lifter pad also rotates.

First and second annular tools 3 and 4 are mounted for free rotation in first and second carrier plates 5,6.

Figure 6 shows a sectioned side view of a freely rotating tool 3 and its holder 5. The holder 5 has a large aperture to accommodate the tool 3 on ball bearings 8 and a small hole at the other end to receive an actuating shaft 42.

As the turret rotates a rotating lifter pad 1 is urged by cam 41 to lift a can and end assembly up into the first operation tool. The shaft 42 is urged to twist by cam 44 to bring the first annular tool 3 to a first operation seaming position, as the turret rotates, from a concentric position of can and tool at the left of Figure 7 to a position at the top of Figure 7. In this first seaming position the first tool 3 is moved laterally against the periphery of the can end E to create the first operation seam.

Continued rotation of the turret brings the can with first operation seam to the position shown at the right of Figure 7 in which cams 43 and 44 have brought the tools 3 and 4 to be concentric with the can, seaming chuck and lifter pad so that the seaming chuck and the lifter pad may move simultaneously to bring the first operation seam level with the seam forming profile of the second operation tool 4. Then, as the turret continues rotation, the second carrier plate 6 is urged by twisting of the hollow shaft 52 by cam 43 to bring the second tool 4 into operation to complete the double seam. On further rotation of the turret, the tools are returned to the position at which they are concentric with the can body. The lifter pad is then lowered by cam 41 to permit removal of the seamed container from the apparatus. It will be noticed that each lifter pad is resiliently supported by a spring 45 which serves to permit control of axial pressure on the can and protect the apparatus from excessive top load. In this embodiment, coaxial shafts 42, 52 are used to move the first and then the second carrier plate. In another embodiment a single shaft may be rotated clockwise to operate one tool and then anticlockwise to operate the other tool, as shown in Figure 4.

Claims

1. Apparatus for seaming a container end to an open end of a container body in at least first and second seaming operations: means to support the container body; a seaming chuck to support the end in place on the container body; and means for progressively folding peripheral portions of the container body and end together to form a seam; wherein the folding means comprises at least two annular seaming tools providing at least first and second annular seaming profiles on an inner surface or surfaces thereof which surround the end and wherein the apparatus includes means for moving the annular seaming tools laterally with respect to the end so as to come into engagement therewith, and drive means for driving the container or the seaming tool in rotation about their axes such that when the can end and an annular seaming tool are brought into engagement they both rotate about their respective axes and roll relative to one another so as to form the seam progressively; characterised in that there is provided means for causing relative movement between the end and the annular seaming tools, from a first relative position in which the first seaming profile can contact the end to perform the first seaming operation, to at least a second relative position in which the second seaming profile can contact the end to perform the second seaming operation.

2. Apparatus according to Claim 1, wherein the means to support the container body is a lifter pad and wherein the drive means transmits rotary drive to the chuck which transmits rotary drive to the can end, the can body and the lifter pad.

3. Apparatus according to Claim 2, wherein the seaming tools are mounted for free rotation about their axes.

4. Apparatus according to Claim 1, wherein the seaming tools are driven in rotation about their axes and wherein the means to support the container body and the seaming chuck are mounted for free rotation about their axes.

5. Apparatus according to any preceding claim, wherein the seaming tools are formed separately from one another and are independently movable into engagement with the container end.

6. Apparatus according to any one of Claims 1 to 4, wherein the seaming tools are formed integrally or as a single unit.

7. Apparatus according to any preceding claim, wherein the seaming tools are mounted for reciprocal linear motion in a horizontal plane to move them into and out of engagement with the can end.

8. Apparatus for seaming an end to the open end of a container body substantially as described herein with reference to the accompanying drawings.