IES922925A2 - A bag or tube-forming apparatus - Google Patents

Abstract

Apparatus for forming tubes or bags from two layers (3,4) of sealable packaging film material such as polyethylene bubble film comprises two roll holders (1,2) for feedstock film material, and two A-frames (5,6) to twist respective webs of film unwound from the rolls to an overlying arrangement on a horizontal conveyor bed (7). Three parallel, independently-controlled, heat sealers (9) form bag or tube sides in the direction of travel of the conveyor, which are then slit longitudinally and transversely to separate bags or tubes of the desired dimensions from the web which are automatically stacked by means of a vertical conveyor arrangement (13). If bags are being formed, a transverse heat sealer forms bag ends prior to separation from the web at a final cutting station (12).

Description

The present invention relates to a bag or tube-forming apparatus, in particular to apparatus for forming bags or tubes from plastics or plastics-coated film material, especially suited to conventional polyethylene bubble or foamed film material used as a cushioning material in packaging applications.

In certain packaging applications, open-ended bags, or tubes (bags open at both ends) are required in various sizes, necessitating bag-forming apparatus which can be quickly set up to produce bags or tubes of the required dimensions, and with different rolls of feedstock film material. However, the output rate is largely determined by the need to manually remove and stack the bags or tubes as they are produced in conventional machinery. It will be appreciated that a low unit cost to volume ratio must be achieved in the case of a packaging product such as a cushioning jacket or envelope which is discarded as waste by the customer.

According to the present invention, there is provided a bag or tube-forming apparatus comprising:35 means to unwind a first and second film of sealable or bondable material in a layered web relation to a substantially horizontal conveyor bed, 0988S IE 922925 - 2 drive means to convey said first and second webs along the horizontal conveyor bed, - first sealing means disposed generally in the direction of travel of the conveyor bed, to seal the webs together to form bag or tube sides, second sealing means disposed generally transverse to the 10 direction of travel of the conveyor bed, to seal the webs together, to close bag ends, a substantially upright conveyor downstream of the first sealing means arranged to direct the sealed film webs to a generally horizontally disposed film-cutting station, and output conveyor means adjacent to the cutting station arranged to direct bags or tubes separated from the web of sealed film away from the cutting station in a stacked orientation.

Preferably, the second sealing means is located at the said film-cutting station, or both may be comprised by a combined sealer/cutter.

Preferably, the unwinding means comprises a substantially horizontally disposed roll holder. The roll holder may be static and mounted on a swinging pivot, or mobile and mounted on locking wheels.

Advantageously, two roll holders are disposed with their axes substantially horizontal, to feed the first and second films via a pair of A-frames to the horizontal conveyor bed. The A-frames may be oppositely inclined and offset, or are fully adjustable, in orientation with respect to the horizontal conveyor bed.

IE 922925 - 3 Preferably, a web tension compensator is disposed downstream of the drive means on the horizontal conveyor bed.

The first sealing means preferably comprises a series of one or more parallel, independently-controlled heat sealers. Suitably, two to five parallel heat sealers may be accommodated across the width of the horizontal conveyor bed. Each sealer is preferably adapted to produce a tramline seal, defining an unsealed gap between two parallel seal lines, to be subsequently slit by an adjacent slitting blade arrangement along the said gap downstream of the sealer, allowing the edge formation of a series of side-by-side bags or tubes on the web. The said gap is preferably about 12 mm.

The second sealing means is preferably incorporated in the cutting station as a combined sealer/cutter. Advantageously, the whole sealing/cutting head is independently movable to adjust the length of the bag or tube being formed.

Optionally, the second sealing means comprises a broad band sealer disposed substantially across the width of the horizontal conveyor bed. The broad band sealer preferably produces a seal of about 16 mm in width.

All heat sealers preferably comprise heated elements arranged above and below the web which are each independently controlled. A separate web of non-stick film material is preferably drawn slowly or intermittently transversely across the horizontal conveyor bed in between each respective heated element and the adjacent web of sealable material.

The upright conveyor preferably carries the sealed web to a height of about 1.2 metres above the level of the horizontal conveyor bed. The upright conveyor preferably includes auxilliary drive means A preferred embodiment of a bag or tube-forming apparatus will now be described with reference to the accompanying drawings, in which IE 922925 - 4 Figure 1 is a schematic side view of the apparatus, and Figure 2 is a schematic plan view of the apparatus.

The bag or tube-forming apparatus as shown comprises two roll holders 1, 2 arranged to unwind plastics or plastics-coated film material in a web 3, 4 to a respective A-frame 5, 6, made of stainless steel and inclined at about 45° so as to twist the webs 3, 4 pulled from the rolls into a horizontal orientation. The webs then pass from each A-frame one above the other along a horizontal conveyor bed 7. Electromagnetic edge guides may be used to keep the webs straight as they are unwound. The webs are typically 600 mm wide and may be of REEDX (trademark) film, polyethylene bubble film (2-ply with bubbles facing out, or 3-ply with bubbles enclosed), LDPE foam, anti-static and conductive polyethylene film, plastics and paper or metallic foil laminates, foil barrier material, co-extruded polyethylene, or ordinary polyethylene film. The films need not necessarily be plastics-coated, but are preferably heat sealable, or bondable by other means such as ultrasonic welding.

A main drive roller 8 pulls the webs 3, 4 along the horizontal conveyor 7. A tension compensator arrangement ensures constant feed of delivery to the lateral heat sealers 9. These comprise a parallel arrangement of three dual heat elements located above and below the webs 3, 4 which are suitably water-cooled. Each pair of heated elements provides a tramline seal defining a gap of 12 mm between two parallel seal lines. Parallel slitting blades 10 are then arranged adjacent to the lateral heat sealers 9, to slit the sealed webs 3, 4 along the gap, longitudinally of the web, or as required.

If tubes are being formed, the web is fed directly to the transverse cutter 12. However, if bags are being formed, the web which has been slit longitudinally may also be sealed transversly at the cutting station 12, i.e. the cutter 12 may be a sealer/cutter or may provide a mixed weld seal. When a broad transverse seal is required, broad band sealer 11 is activated which forms a transverse seal across the web of about 16 mm width at the desired intervals.

The sealed and slit web then proceeds via the upright conveyor arrangement 13 to the transverse cutting station 12. Bags or tubes IE 922925 - 5 15 which are cut from the web are fed downwardly by pneumatic ejectors and grippers (not shown) to an output conveyor 14, and stacked in the process.

The heat sealers may be mixed head sealers with rubber grips, with a constant heat supply or providing a heat impulse. When using plastics film material, a transverse web of non-stick film is fed transversely across the gap between the heat sealer elements and the web of plastics film being carried along the horizontal conveyor bed. This may be drawn slowly or intermittently across the conveyor bed to prevent sticking of the plastics film material to the heat sealer elements. Conventional take off, compensator counterbalancing rollers are provided as appropriate. Auxilliary drive rollers 16, 17, and a static eliminator 18 are also preferably provided.

The system is designed generally to ensure accurate bag/tube widths and draw lengths which is a problem when dealing with thick film materials, such as bubble film.

Claims (5)

1. A bag or tube-forming apparatus comprising:5 - means to unwind a first and second film of sealable or bondable material in a layered web relation to a substantially horizontal conveyor bed, drive means to convey said first and second webs along the 10 horizontal conveyor bed, first sealing means disposed generally in the direction of travel of the conveyor bed, to seal the webs together to form bag or tube sides, second sealing means disposed generally transverse to the direction of travel of the conveyor bed, to seal the webs together, to close bag ends, 20 - a substantially upright conveyor downstream of the first sealing means arranged to direct the sealed film webs to a generally horizontally disposed film-cutting station, and output conveyor means adjacent to the cutting station 25 arranged to direct bags or tubes separated from the web of sealed film away from the cutting station in a stacked orientation.

2. A bag or tube-forming apparatus according to claim 1, comprising 30 two roll holders disposed with their axes substantially horizontal, to feed the first and second films via a pair of A-frames to the horizontal conveyor bed, wherein the A-frames are oppositely inclined and offset, or are fully adjustable, in orientation with respect to the horizontal conveyor bed. IE 922925 - 7

3. A bag or tube-forming apparatus according to claim 1 or claim 2, in which the first sealing means comprises a series of at least three parallel, independently-controlled heat sealers, accommodated across the width of the horizontal conveyor bed, wherein each sealer is 5 preferably adapted to produce a tramline seal, defining an unsealed gap between two parallel seal lines, to be subsequently slit by an adjacent slitting blade arrangement along the said gap downstream of the sealer, allowing the edge formation of a series of side-by-side bags or tubes on the web.

4. A bag or tube-forming apparatus according to claims 1, 2 or 3, in which the second sealing means comprises a broad band sealer disposed substantially across the width of the horizontal conveyor bed.

5. A bag or tube-forming apparatus, substantially as described herein with reference to, and as shown in, the accompanying drawings.