AU2003252868A1 - Bag cutter - Google Patents

Description

Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

Name of Applicant: Actual Inventor(s): Address for Service: Invention Title: JOSEPH FRANK KOCSIS JOSEPH FRANK KOCSIS SANDERCOCK COWIE SUITE 8C, 50-54 ROBINSON STREET DANDENONG VIC 3175 BAG CUTTER Details of Associated Provisional Application(s): No(s): Australian Provisional Application No. 2002951900 Filed: 8th October, 2002 The following statement is a full description of this invention, including the best method of performing it known to me: -1- Fc2003-10-08,A:\470kocsis.file.wpd, I la- TITLE: BAG CUTTER FIELD OF THE INVENTION This invention concerns cutters for cutting a ply of flexible material such as fabric or plastic sheet. The invention is useful in plastic bag-forming machinery and especially side-sealing bag cutters.

BACKGROUND OF THE INVENTION 0 Plastic packaging is made in great quantity and machinery for its production is subject 2003-10-08.A:\463kocsis.cap.wpd, I to continual improvement. The invention is described with reference to side sealing bag cutters, but those skilled in the art will see that the design is applicable to any film handling machine where waste film is excised and removed from the cutting site.

SUMMARY OF THE INVENTION The apparatus aspect of the invention provides a flexible ply cutter comprising means to cut a flexible ply, means to eject the severed portion of ply toward capture means to both capture the severed portion and convey the severed portion from the cutting site.

The means to cut and seal the ply may be a blade and platen capable of sealing the ply.

The capture means to both capture and convey the severed portion from the cutting site may be a roller nip.

The means to move the severed portion towards the capture means may be an ejector such as a finger. Alternatively, the ejector may be a gripper which pulls the severed portion away from the cutting site.

The capture means may be adjacent and preferably close to the cutting site so that the pusher displaces the severed portion out of the feed path which the plies follow through the cutter. The path may be defined by a feed surface of which the plies are indexed and the path may have an exit aperture at the cutting site through which the severed portion is pushed into the roller nip.

The rollers may be stepped so as to define one or more cavities into which the severed portion is admissible, urged by the ejector. The ejector may extend into a cavity beyond the rotational axis of the top roller because the pusher enters the cavity defined by the roller step. The rollers may drive belts so that the belts provide the nip. The belts may be coated to provide resistance to adhesion by the severed portion which may be adherent from the hot blade.

The rollers may be part of an assembly in which one set of rolls rotate on fixed axes and 2003-1 0-08,A:\463kocsis.cap.wpd,2 -3the companion set are capable of floating in order to accommodate severed portions of different bulk. As plies increase in thickness or the area of the excised ply portion increases, the device must dispose of a bigger waste portion in the same time period unless the time period is adjustable. Accordingly, we find that allowing the belts to separate without interruption to their feed motion is a useful design solution. The steps in the rollers assist passage of the excised waste. Only the upper rollers of such an assembly need be stepped. The rolls preferably rotate continuously.

The diameter of the rolls may be 4-15mm in order to be set close to the exit aperture.

The pusher need not contact the rollers or belts. The area surrounding the exit aperture may be reduced in thickness at the under surface in order to allow close location of the top rolls. The surface against which the blade and plate close may be coated to lessen the adhesion of the hot plastic to the surface. When the rolls are stepped, the ejector may be bifurcated in order to push the severed portions into two side by side cavities in the top rolls.

Alternatively, the capture means may comprise a collection space subject to intermittent partial vacuum, whereby the portions are removed from the space. Intermittent application of vacuum may be imposed by a gate which opens and closes.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevation of the machine with the operative parts ready to seal a folded web in the course of making a bag chain.

Figure 2 is a side elevation of the machine with the operative parts excising and sealing.

Figure 3 is a side elevation of the machine ejecting.

Figure 4 is a front elevation of the Figure 1 embodiment.

Figure 5 is a plan view of the top roller pair.

2003-. 10-08,A:\463kocsis.cap.wpd.F3 -4- Figure 6 is a close up plan of the cutting and sealing parts.

DETAILED DESCRIPTION WITH RESPECT TO THE DRAWINGS The device described makes repeat cuts and seals in the folded plastic web which feeds to a subsequent machine for further treatment to enable the chain of bags to be filled.

During the momentary feed pause, a round bottom punch performs its seal and cut operation.

Referring now to the drawings, prior to the commencement of cyclic operation, the cutter retract actuator 2 lowers the cutter actuator 4 and cutter 6 to the running position. This relatively large motion positions the cutter 6 close enough to the plastic web 8 for the high speed, low stroke cutter actuator 4 to be able to contact the silicone coated sealing base 10. The sealing base 10 has an exit slot 12. The ejector 14 is reciprocated by separate actuator 16. The ejector penetration is controlled by adjuster 18. The cutter 6 is free to move up and down past the ejector because the cutter has an ejector slot The cutter resembles an inverted V. It is surrounded by a heated block 22 which is separated from the actuator by an insulating pad 24. During cyclic operation the cutter actuator rapidly lowers the cutter to simultaneously seal and cut the plastic web on the sealing base. The cutter remains in contact for an adjustable period and is then retracted by the cutter retract actuator.

After an adjustable delay from the commencement of the cutter actuation, the ejector actuator rapidly lowers the ejector into the exit slot 12. The ejector then rapidly retracts back to its UP position. This ejection process separates the off-cut that results from the seal/cut operation and pushes it through the ejection slot 12 (28mm long) into the ejection nip. The ejection nip is formed by paired nip rolls 26, 28, covered by silicone covered belts 30, 32 (48mm wide). These are arranged directly beneath the exit aperture defining a vertically downward path into a waste collection receptacle (not shown). The top roll pair is stepped so as to define the side by side cavities 34, 36 into which the ejector extends. The bottom rolls are plain.

Referring now to Figure 4, the left hand belt is driven by motor 36, while the right hand 2003-10-08,A: 463kocsis.cap.wpd,4 belt is urged against the left hand belt by spring linkage 38.

The actuators of the various mechanisms of the machine are conventional, namely pneumatic cylinders, stepper motors and servo motors.

We have found the advantages of the embodiment described above to be:- 1. The rate of fault-free removal of waste was in the prior art devices a rate determining step for the overall production of chain bags, whereas this device is capable of speed match with the accompanying web treatment processes.

2. High reliability of off-cut removal.

3. Applicability to other cutting and optional sealing operations where an off-cut results, for example carry bag handgrip punching.

The claims, illustrations, photographs and drawings, if any, form part of the disclosure of this specification as does the description, claims, illustrations, photographs and drawings of any associated provisional or parent specification or of any priority document, if any, all of which are imported hereinto as part of the record hereof.

Finally it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements or parts without departing from the spirit and ambit of the invention.

2003- 10 08,A:\463kocsis.cap.wpd,5

Claims (17)

1. A flexible ply cutter comprising means to cut a flexible ply, means to eject the severed portion of ply toward capture means to both capture the severed portion and convey the severed portion from the cutting site.

2. A flexible ply cutter as claimed in Claim 1, wherein capture means is a roller nip.

3. A flexible ply cutter as claimed in Claim 1 or 2, wherein means to move the severed portion toward the capture means is an ejector.

4. A flexible ply cutter as claimed in Claim 1 or 2, wherein the means to move the severed portion towards the capture means is a gripper which pulls the severed portion away from the cutting site. A flexible ply cutter as claimed in Claim 3 or 4, wherein the capture means is close to the cutting site and the ejector displaces the severed portion out of the feed path which the ply takes to the cutter means.

6. A flexible ply cutter as claimed in Claim 5, wherein the feed path is defined by a feed surface over which the ply is intermittently fed and the end of the path is an exit aperture at the cutting site through which the severed portion passes.

7. A flexible ply cutter as claimed in any one of Claims 2-6, wherein the rollers are stepped so as to define one or more cavities into which the severed portion is admissible, urged by the ejector.

8. A flexible ply cutter as claimed in Claim 7, wherein the ejector extends into a cavity beyond the rotational axis of the roller.

9. A flexible ply cutter as claimed in Claim 7 or 8, wherein the stepped rollers are the top rollers of a top and bottom pair which drive belts so that the belts provide the nip. 2003 -10-08,A:463kocsis.cap. wpd,6 -7- A flexible ply cutter as claimed in Claim 9, wherein the belts are coated to reduce adhesion of the ply.

11. A flexible ply cutter as claimed in Claim 9 or 10, wherein the rollers are part of an assembly in which a set of rollers rotate on a fixed axis and the companion set are floating.

12. A flexible ply cutter as claimed in any one of Claims 2-11, wherein the rollers rotate continuously.

13. A flexible ply cutter as claimed in any one of Claims 6-12, wherein the area surrounding the exit aperture is reduced in thickness at the undersurface to allow close location of the top rollers.

14. A flexible ply cutter as claimed in any one of Claims 3-13, wherein the ejector is bifurcated. A flexible ply cutter substantially as herein described with reference to and as illustrated in Figures 1-6.

16. A flexible ply cutter as claimed in any one of claims 1-15, wherein the cutter operates as a plastic bag cutter.

17. A method of waste removal in a cutting operation on a ply or plies, comprising severing a flexible ply to produce a severed portion, ejecting the severed portion of ply toward captured means, capturing the severed portion and conveying the same from the cutting site.

18. A method as claimed in Claim 17, wherein ejection is achieved by pushing the severed portion away from the cutting site.

19. A method as claimed in Claim 16, wherein ejection is achieved by gripping the severed portion and pulling it away from the cutting site.

2003-10-08,A:\463kocsis.cap.wpd,7 -8- A method as claimed in any one of Claims 17-19, wherein capture is achieved by ejection of the severed portion into a roller nip. 21. A method as claimed in Claim 20, wherein the rollers are continuously rotated. 22. A method of waste removal in a ply cutting operation which creates a severed ply portion, substantially as herein described. Dated this 8 th day of October, 2003. SANDERCOCK COWIE PATENT ATTORNEYS FOR JOSEPH FRANK KOCSIS 2003-10-08,A:\463kocis.cap.wpd,8