EP0091813A2

EP0091813A2 - Closure apparatus

Info

Publication number: EP0091813A2
Application number: EP83302027A
Authority: EP
Inventors: Rik Noten
Original assignee: Ekco NV
Current assignee: Ekco NV
Priority date: 1982-04-13
Filing date: 1983-04-12
Publication date: 1983-10-19
Also published as: EP0091813B1; EP0091813A3; DE3369293D1; ATE25054T1

Abstract

Closure apparatus for securing a foil cover (6) to a foil container (8) includes cutting means (1,2) adapted to cut the cover to size on initial closure of the apparatus. The edge of the cover is bent towards the container by further closure of the apparatus and means (4, 5) are provided to turn the cover edge under the lip of the container. Crimping means (8) are provided to seal the cover. The foil stock for the cover may be fed automatically into the apparatus from a stock roll.

Description

The invention relates to apparatus for closing containers especially containers made of aluminium foil.
In one type of known closing apparatus, such as that described in German Offenlegungsschrift 2511218, an aluminium container is placed in a die, a preformed cover is placed on the container and the die is closed in such a way that the cover is secured to the container by bending the edges of the cover under the rim of the container.
According to our invention the cover is formed in the die from a sheet of aluminium or other foil material, during the closing operation.
Thus the present invention provides in one aspect a closure die including an upper die part, a lower die part having a support for a foil container and means responsive to relative movement between the die parts to secure a cover to the container, characterised thereby that the closure die further includes cutting means adapted to cut a cover for the container on relative movement between the die parts.
In one embodiment the upper die part is fixed and the lower die part is movable towards the upper die part.
The cutting means may comprise a movable knife and a fixed knife. Preferably the movable knife is pivoted at one end and adapted to cut a cover by means of a scissor action. Preferably at the other end the movable knife is releasably connected to the lower die part whereby when the lower die part moves upwards the movable knife moves with it until a predetermined point when the movable knife is disengaged. The releasable connection may comprise spring-loaded detent means for engagement with a detent of the movable knife. Preferably the arrangement includes stop means on the fixed knife which is adapted to prevent passing movement of the movable knife. The detent means may be part of a tiltable support which is connected to the lower die part.
The upper part of the die preferably includes means for compressing the sides of the cover around the rim of the container. Said compressing means may comprise a plurality of resilient frame members which are spaced apart when the die is open and means for compressing the resilient frame members together when the die closes whereby the edges of the cover can be secured under the rim of the container.
The resilient frame members may be made of nylon or other plastics material.
The upper part of the die may include rigid guides associated with the resilient frame members, said rigid guides being arranged to be moved inwards and thereby press the resilient frame members together. This arrangement may include tapered guides, which are adapted to push the rigid guides inwards as the rigid guides and associated resilient frame members are moved relative to the lower part of the die.
Preferably there are four resilient frame members of angled shape which together form a substantially rectangular shape and there are four rigid guides, one on each side of the rectangle.
Preferably the closure die includes guide means for the foil sheet, the guide means having slots into which the edges of the foil sheet fit; the slots being such that the foil sheet can be pushed out of the guides by relative movement of the upper and lower die parts and can be bent downwards as the edges leave the slots in the guide members.
Preferably the apparatus includes means for carrying a roll of foil sheet material and for feeding foil sheet from a roll into the slotted guides.
The lower die part may include an inner frame and an outer frame, the inner frame being adapted to support a container which is to be closed and the outer frame being adapted to complete sealing of a cover on the container by compressing a bent edge of the cover under the rim of the container.
The invention also includes a method of closing a foil container, which method comprises placing a foil container on the lower part of a closure die having upper and lower parts, feeding foil sheet material between the upper and lower parts of the die, cutting the foil sheet material to provide a cover for the container and closing the die to secure the cover to the container. Preferably the foil sheet material is cut to size as the die closes.
Other features of the invention are disclosed in the following description of a preferred embodiment shown, by way of example only, in the accompanying drawings in which:-

Figures 1 to 6 are end views partly in section, of an apparatus for closing containers showing the sequence of steps for effecting closure;
Figure 7 is a plan view of the closing die;
Figure 8 is a cross-section through part of the die; and
Figure 9 is a view similar to Figure 1.

Referring now to the drawings in detail and Figures 7, 8 and 9 in particular, the closing die comprises a movable cut off knife 1, which is movable in an upward direction; the knife having a pivot 19 at one end (see Figures 1 to 6 and 9) and a notch 27 at the other end (see best in Figure 3). The notched end of the knife rests against a ball bearing 11, which is fixed to a tiltable support frame 10, which forms part of a lower die. There is a fixed knife edge 2 (see Figure 9) which serves as a cutting support for the knife 1. As seen in Figure 7 a resilient frame 4 (made of nylon), consisting of four individual sections normally biassed apart by compression springs 26,has four shaped rigid guides 5 (made of steel) along its short and long sides. These guides 5 are used to compress the frame 4 and to give support to the relatively weak frame 4. Referring to Figure 1 there is a support plate 17 for the lower die which comprises an inner die frame 8 and an outer die frame 9. An ejector plate 14 has guide pins 13. The inner die frame 8 has loading springs 15. The upper die comprises a frame 3, the nylon frame 4 (see also Figure 7) and its steel guides 5. The nylon frame has cavities 20 for the compression springs 26 (see Figure 7). The upper die frame 3 has support posts 21 fixed to a carrying plate 22. The plate 22 has return springs 23. The upper die also has guide pins 24 and a support plate 25.
The closing die operates in the following way.
Figure 1 shows the die in the open, or start position. An aluminium foil container 7 is placed on the ejector plate 14. Aluminium foil sheet 6 is fed from a roll (not shown) through guides 18 into the "fed" position (Figure 1) above the container 7 and under the upper die. The support frame 17 is moved upward (Figure 2) by rams 28 pushing the lower inner die frame 8 under the shoulder of the container 7 which is then lifted from the ejector plate 14.
The support frame 17 carries the ball bearing support frame 10 with it. The ball bearing 11 rotates against and guides the movable cut off knife 1 upwards about its pivot 19 so cutting the foil sheet 6 against the fixed knife edge 2 by means of a scissor action thus forming the foil cover for the container. The movable knife 1 meets a stopper pin 12 which causes the bearing 11 to leave the notch 27 of the knife 1 thus disconnecting the knife from the bearing 11 as seen in Figure 3. The foil container 7 moves under and engages the foil cover 6. The continued upward movement of the container 7 pulls the cover 16 out of its guide 18. This results in the edges of the cover 6 being bent downwards, on its two short sides as shown in Figure 4.
Referring now to Figures 3 to 5, the ball bearing 11 has left the notch 27 in knife 1 completely while the knife rests against stopper pin 12. The foil container 7 with its cover 6 continues to move upwards supported and guided by the inner frame 8 of the lower die until it pushes against the frame 3 of the upper die and into the area of the nylon frame 4. The nylon frame 4 is compressed by the tapered steel guides 5, thus moving inwards to bend the edge of the cover 6 under the shoulder of the container as shown in Figures 5 and 5a. The outer frame 9 of the lower die moves up under the ledge against the effect of springs 15, tightening the cover 6 under the shoulder of container 7 as shown in Figures 6 and 6a.
After closure the support 17 for the lower die is moved downwards, the notch 27 in knife 1 engages the bearing 11 and resets it to the start position shown in Figure 1. The closed container may be removed from the die preferably by automatic means and a fresh container inserted for closure.
In the above embodiment of the invention the combined thickness of the nylon frame 4 and the movable cut off knife 1 is equal to the width of foil sheet material 6 protruding beyond the rolled edge of the container. This width will depend on the size of container being sealed. For one particular size it amounted to 12 mm.
The apparatus described above has the advantage that the lid can be cut from a roll of foil and shaped during the closing operation.

Claims

1. A closure die including an upper die part, a lower die part having a support (14) for a foil container (8), and means responsive to relative movement between the die parts to secure a cover (6) to the container (8) characterised thereby that the closure die further includes'cutting means (1, 2) adapted to cut a cover for the container on relative movement between the die parts.

2. A closure die according to Claim 1, characterised thereby that said cutting means comprise a fixed knife (2) and a movable knife (1).

3. A closure die according to Claim 2, characterised thereby that the movable knife (1) .is pivoted at one end and adapted to cut a cover (6) by means of a scissor action.

4. A closure die according to Claim 3, characterised thereby that one of said upper and lower die parts is fixed, the movable knife (1) having a releasable connection at its other end to the other of said die parts, and the die including stop means to disconnect said releasable connection on closure of said fixed and movable knives.

5. A closure die according to Claim 4, characterised thereby that said releasable connection comprises spring loaded detent means (10, 11, 16) mounted on the other of said die parts for engagement with a detent (27) of the movable knife (1).

6. A closure die according to Claim 4 or Claim 5, characterised thereby that said stop means comprise an abutment (12) of the fixed knife (2) adapted to prevent passing movement of the movable knife (1).

7. A closure die according to any preceding claim, characterised thereby that the die further includes means for carrying a roll of foil sheet material, means for feeding foil sheet from the roll into said die and guide means of the die having slots (18) to receive and guide edges of the foil sheet.

8. A closure die according to any preceding claim, characterised thereby that the die further includes means to bend the edge of a cover (6) towards the container (8).

9. A container closing machine incorporating a closure die according to any one of the preceding claims.

10. A method of closing a foil container (8) and comprising the steps of

(a) placing a foil container (8) on the lower part of a closure die having upper and lower die parts;

(b) feeding foil sheet material between the upper and lower parts of the die;

(c) cutting the foil sheet material to provide a cover (6) for the container (8); and

(d) closing the die to secure the cover (6) to the container (8).