EP2391466B1

EP2391466B1 - Necker infeed

Info

Publication number: EP2391466B1
Application number: EP09782357.9A
Authority: EP
Inventors: Daniel Egerton
Original assignee: Crown Packaging Technology Inc
Current assignee: Crown Packaging Technology Inc
Priority date: 2008-09-05
Filing date: 2009-08-28
Publication date: 2016-03-23
Anticipated expiration: 2029-08-28
Also published as: EP2391466A1; GB0816167D0; WO2010026115A1

Description

Technical Field

This invention relates to necker infeed for metal can manufacture and, in particular to the introduction of can bodies to a necker assembly for reducing the diameter of an open end of a can body.

Background Art

Although it is known to reduce the diameter of the open end of the can body by a "spin necking" process in which a can body is rotated with rollers that reduce the open end diameter to form "neck", it is more common practice to form the neck by a "die necking" process. In this die necking process, cans are pushed longitudinally into dies so as gradually, over several necking stages, to reduce the neck diameter.
An infeed to a die necking process comprises a row of can bodies, in which the can bodies contact each other. In the infeed, the can bodies thus have a "pitch" (i.e. the distance between their centres) of one can diameter. The can bodies are fed from this infeed to an infeed turret of the die necking machine.
Each turret on the die necking machine has a number of pockets, each pocket being adapted to receive and retain a can body, for example by vacuum. The pockets to carry the can bodies on the infeed turret are separated by a (pocket) pitch. The closer this pocket pitch is to the can body diameter the better the feed onto the infeed turret. This can be achieved by having a large number of pockets on the infeed turret so as to bring the pockets closer together.
At the inlet to each necking stage of one type of known high speed necking machines, there is a dual turret infeed. In such machines, the infeed turret is fitted in combination with a waxer turret. The waxer turret is required for applying a protective film of lubricant to the outside of each can body so as to reduce the friction as the can enters the tooling.
Ideally, the waxer turret has a pair of rubber rollers which are used to rotate the can about its own axis. The rollers hold the can on the theoretical pitch circle radius of the turret. The rollers are made of resilient rubber since, if the rollers were of soft rubber, the can would be able to deflect the rollers and move around. As a can is passed from the infeed turret to a waxer turret, it is imperative that the can meshes with the rollers. If the can touches the rubber rollers too early, for example, this would crush the can.
One way to avoid this problem is to have the same number of pockets (for example 12) on the infeed and waxer turrets. When the number of pockets matches, the clashing is not a problem as the can meshes with the rollers.
If the waxer turret does not have rollers, the infeed will work with a different number of pockets on infeed and transfer turrets. It is only the presence of waxer rollers, which may cause a problem with this type of dual turret infeed.
An alternative solution is to offset the turrets from each other slightly so that the can is able to pass "in front" of the rollers at the transfer point. The can is then guided onto the waxer turret. This solution has been provided on a dual turret infeed, having 15 pockets on the infeed turret and 12 pockets on the waxer turret. The offset is introduced due to the different number of pockets together with the presence of the waxer rollers.
Feeding cans directly to the waxer turret has also been tried in US-5,206,054 but in the case of a large increase in pitch from infeed trackwork to waxer turret this was unsuccessful, because as the waxer turret grabs a can out of the infeed trackwork and takes it away for processing, following cans are able to squeeze past the back of the pocket on the waxer. This means that either the cans are picked up 'too far down' in the trackwork, leading to dented cans, or in the worst case, two cans could be fed simultaneously.
There still exists a need for a die necker infeed which combines the benefits of improved feed from an infeed turret having a greater number of pockets than are provided on the waxer turret, whilst avoiding the problem of crushing of the can and without the need for careful set up to offset the turrets.

Disclosure of Invention

According to the present invention there is provided an infeed assembly for a can necking apparatus, the infeed assembly having an infeed turret and a waxer turret and in which the infeed assembly further includes a transfer turret between the infeed turret and the waxer turret, the number of pockets on the transfer turret being the same as the number of pockets on the waxer turret.
In a preferred embodiment the waxer turret includes a pair of rollers for each pocket position. The infeed turret may have a substantially larger number of pockets for holding can bodies than the number of pockets on the transfer turret, ideally twice the number of pockets as the number of pockets on the transfer turret.
The distance between the centres of the pockets on the infeed turret is ideally as close as possible to the diameter of can bodies which, in use, are handled by the assembly.

Brief Description of Figures in the Drawings

The invention will now be described, by way of example only, with reference to the drawings, in which:

Figure 1 is a schematic cross-section of a dual turret infeed assembly, showing differing numbers of pockets on the infeed and waxer turrets;
Figure 2 is a schematic similar to that of figure 1, showing a matching number of pockets on the turrets;
Figure 3 is an assembly drawing of the triple turret infeed of the present invention; and
Figure 4 is a schematic of the assembly drawing of figure 3.

Mode(s) for Carrying Out the Invention

The cross-section of figure 1 depicts a 16 pocket infeed turret 10 and a can 5 passing from a pocket 12 on the infeed turret to a pocket 14 on a waxer turret 20. The waxer turret 20 has a pair of rollers 16 for each of 12 pocket positions. These rollers are used to turn the can about its own axis for even application of the wax. As can best be seen from the enlarged view of figure 1a, when the can passes from the pocket 12 of the infeed turret 10 to the pocket 14 of the waxer turret, the can touches the rubber rollers 16 too early. This would result in the crushing of the can, necessitating shutdown of the entire machine.
An alternative to the prototype of figure 1 is to match the number of pockets on the infeed turret to the number on the waxer turret as shown in figure 2. The infeed turret 15 of figure 2 has 12 pockets 18, as does the waxer turret 25. When the number of pockets match, the can 5 meshes cleanly with the rollers 16 of the waxer turret. However, as noted above, more pockets on the infeed turret gives a better result, so that this is not the optimum solution.
The triple turrets of the present invention are shown in side section in figure 3. Turret 30 will be referred to as the "infeed turret", turret 40 will be referred to as the "infeed transfer turret" and turret 50 is the "waxer turret". Cans enter the triple turret assembly via a chute 32 and are guided around S-shaped rail 34 around the turrets. Optionally, a vacuum may be used to aid retention of the cans.
The infeed turret 30 in the example of figure 3 has twelve pockets 36, the infeed transfer turret 40 has six pockets 46 and the waxer turret 50 also has six pockets 56. Although the waxer turret pockets 56 are less easy to see than the pockets of the other turrets in figure 3, a pair of rollers 58 are apparent for each pocket position. The cans are then transferred from the waxer turret 50 into the first necking turret.
The direction of movement of cans around the turrets is shown in simplified form in the schematic of figure 4. As denoted by the arrows, twelve pocket infeed turret 30 receives cans 5 and rotates anti-clockwise. Cans pass from the infeed turret to the six pocket infeed transfer turret which rotates clockwise. Finally the cans are passed to the six pocket waxer turret 50 which rotates anti-clockwise.

Claims

An infeed assembly for a can necking apparatus, the infeed assembly having an infeed turret (30) and a waxer turret (50) and characterized in that the infeed assembly further includes a transfer turret (40) between the infeed turret (30) and the waxer turret (50), the number of pockets (46) on the transfer turret (40) being the same as the number of pockets (56) on the waxer turret (50).
An infeed assembly according to claim 1, in which the waxer turret (50) includes a pair of rollers (58) for each pocket position.
An infeed assembly according to claim 1 or claim 2, in which the infeed turret (30) has a substantially larger number of pockets (36) for holding can bodies than the number of pockets (46) on the transfer turret (40).
An infeed assembly according to any one of claims 1 to 3, in which the infeed turret (30) has twice the number of pockets (36) as the number of pockets (46) on the transfer turret (40).
An infeed assembly according to any one of claims 1 to 4, in which the distance between the centres of the pockets (36) on the infeed turret (30) is as close as possible to the diameter of can bodies which, in use, are handled by the assembly.