AU2005202258A1 - Improved Zipper Rule - Google Patents

Description

Name of Applicant:

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Amcor Limited Andrew Jackson CULLEN CO Patent Trade Mark Attorneys, 239 George Street Brisbane Qld 4000 Australia Improved Zipper Rule Actual Inventor: Address for Service: Invention Title: Details of Associated Provisional Applications: Application No. 2004904137 filed 26 July 2004 The following statement is a full description of this invention, including the best method of performing it, known to us: In 2

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0 Field of the Invention The present invention relates generally to perforated tear lines and, in particular, to perforated tear lines for sheets, envelopes, containers and the like which In are fabricated from a tearable material such as paper or paper-based materials such as fibreboard or cardboard.

00 IBrief Discussion of the Prior Art Perforated tear lines are often used in connection with paper-based products I such as writing paper, envelopes, and containers to allow parts thereof to be torn off with relative ease. The simplest type of perforated tear line consists of a row of holes or slits which are cut into the paper-based material along which the line extends.

Figure 1 illustrates an example of a prior art perforated tear line which is often used to define tear strips of envelopes, containers and the like. The tear line includes a plurality of cuts that are spaced apart from each other. Each of the cuts includes a leading portion, and a trailing portion which is inclined with respect to the leading portion. Each leading portion extends from and is inclined with respect to a nominal tear line which is denoted by the dashed line in figure 1. Each leading portion extends along the nominal tear line.

Figure 4 illustrates a tear strip which is defined by two of the perforated tear lines illustrated in figure 1 and which is adapted to be torn from the material on either side of the strip in the direction of the arrow which is located above figure 6. The tear lines, which are the mirror image of each other, are both parallel and laterally offset with respect to each other. A grasping tab is defined at one end of the strip. The tear strip is torn from the material located on either side thereof by grasping the tab and pulling the tab in the tear direction of the strip such that a respective tear propagates along each of the tear lines.

In order for the tear strip illustrated in figure 4 to be cleanly torn from the material on either side thereof, each of the tears which propagate along the tear lines must propagate between adjacent cuts of the tear lines by the shortest path which happens to be along the nominal tear line indicated in figure 1. However, if the material from which the tear strip and adjacent sections are formed is a paper-based product such as fibreboard, the tears do not always take the aforementioned path due 3 to various factors such as randomness in the fibre alignment in the fibreboard, and may propagate away from the next cut as illustrated by the uppermost tear depicted in figure 1. In such cases the tear will usually find its way back to the perforated tear n line, however the resulting torn edge which is left behind is usually unsightly. This is particularly undesirable in the case of white-lined fibreboard containers which are o often used for point of sale displays where appearance is an important consideration.

It would therefore be desirable to have a tear line which includes a plurality of cuts and which inhibits tears from propagating other than between adjacent cuts iN when the material along which the tear line extends is torn along the tear line.

Summary of the Invention It is an object of the present invention to overcome, or at least ameliorate, one or more of the aforementioned deficiencies of the prior art, or to provide the consumer with a useful or commercial choice.

Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying illustrations, wherein, by way of illustration and example, a preferred embodiment of the present invention is disclosed.

According to a first aspect of the present invention there is provided a perforated tear line extending along a section of tearable material, the perforated tear line comprising a plurality of cuts in the material that are spaced apart from each other and that are arranged in a line, wherein each of the cuts includes a leading portion extending across a nominal tear line, and a trailing portion extending rearwardly from the leading portion and terminating on the nominal tear line.

According to a second aspect of the present invention there is provided a tear strip extending along a section of tearable material, the tear strip being defined by a pair of laterally separated perforated tear lines that each comprise a plurality of cuts in the material that are spaced apart from each other and that are arranged in a line, wherein each of the cuts includes a leading portion extending across a nominal tear line, and a trailing portion extending rearwardly from the leading portion and terminating on the nominal tear line.

The perforated tear line may be of any suitable length.

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0 It is preferred that the perforated tear line is straight.

The tearable material along which the perforated tear line or tear strip extends may be any suitable tearable material. Preferably, the tearable material is It) paper or a paper-based tearable material such as fibreboard or cardboard.

The cuts may be of any suitable size. Preferably, the cuts are 3 mm to o mm long, and 2 mm to 5 mm wide.

The cuts may be of any suitable shape. Preferably, the cuts are generally o sawtooth-shaped.

It is preferred that the cuts are identical to each other.

0 10 Preferably, the cuts are spaced apart from each other at regular intervals.

In a preferred form, the cuts are arranged in a straight line.

In one preferred form, the leading portion is straight. In another preferred form, the leading portion is curved.

It is preferred that the leading portion is not perpendicular with respect to the nominal tear line and is also inclined towards the trailing portion. Preferably, the leading portion is inclined towards the trailing portion by 450 to 800 with respect to the nominal tear line.

In one preferred form, the trailing portion is straight. In another preferred form, the trailing portion is curved.

Preferably, the trailing portion includes a first sub-portion extending from the leading portion in parallel with the nominal tear line, and a second sub-portion extending from and inclined with respect to the first sub-portion such that the second sub-portion terminates on the nominal tear line. It is preferred that the first and second sub-portions are straight.

Preferably the trailing portion is inclined with respect to the nominal tear line. Preferably, the trailing portion is inclined towards the leading portion by 100 to with respect to the nominal tear line.

Preferably, the nominal tear line intersects midway along the length of each leading portion.

It is preferred that the length of each leading portion on each side of the nominal tear line, and the distance between the cuts is such that a tear is able to migrate between adjacent cuts at an angle of between approximately +25' or 250

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0 with respect to the nominal tear line.

The tear strip may be of any suitable length.

It is preferred that the tear strip is straight.

I Preferably, the perforated tear lines of the tear strip are parallel to each other.

In other preferred forms, the perforated tear lines may, for example, diverge from O0 each other.

It is preferred that the perforated tear lines of the tear strip are the mirror o image of each other.

The perforated tear lines of the tear strip are preferably identical to each other.

Preferably, the tear strip includes a grasping tab.

Brief Description of the Illustrations In order that the invention may be more fully understood and put into practice, a preferred embodiment thereof will now be described with reference to the accompanying illustrations, in which: Figure 1 depicts a prior art perforated tear line; Figure 2 depicts a perforated tear line according to an embodiment of the present invention; Figure 3 depicts a perforated tear line according to another embodiment of the present invention; Figure 4 depicts a prior art tear strip; Figure 5 depicts a tear strip according to another embodiment of the present invention; Figure 6 depicts a tear strip according to a further embodiment of the present invention; and Figure 7 depicts a tear strip according to another embodiment of the present invention.

Detailed Description of the Preferred Embodiment Figure 2 illustrates a perforated tear line 10 according to a first embodiment of the present invention. The tear line 10 may extend across any section of tearable In 6

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0 material such as paper or a paper-based material such as fibreboard or cardboard.

More particularly, the tear line 10 may extend across any section of tearable material which forms part of any suitable article such as a sheet, container, envelope or the In like.

The perforated tear line 10 includes a plurality of cuts 11 in the material that 0 are spaced apart from each other at regular intervals and that are arranged in a line.

Each of the cuts 11 has a sawtooth-shape and includes a leading portion 12 and a otrailing portion 13 which extends rearwardly from and is inclined with respect to the n leading portion 12. Each leading portion 12 extends across a nominal tear line 14 such that the nominal tear line 14 intersects midway along the length of each leading portion 12. Also, each trailing portion 13 terminates on the nominal tear line 14.

The length of each leading portion 12 on each side of the nominal tear line 14 and the distance between adjacent cuts 11 is such that a tear is able to migrate between adjacent cuts 11 at an angle of between approximately 250 or 250 with respect to the nominal tear line 14. Illustrated in figure 2 are tears and "C" which respectively extend between an adjacent pair of cuts 11 at angles of approximately 250, 00, and Figure 3 illustrates a perforated tear line 20 according to a second embodiment of the present invention. For convenience, features of the tear line which are the same or similar to features of the tear line 10 have been referenced with the same reference numbers.

The perforated tear line 20 differs from the tear line 10 in that, unlike the tear line 10, the leading and trailing portions 12, 13 of the cuts 11 are slightly curved.

Figure 5 illustrates a tear strip 30 which also embodies the present invention.

Tear strip 30 is similar to the prior art tear strip illustrated in figure 4 in that it is defined by two perforated tear lines which are the mirror image of each other and which are parallel and laterally offset with respect to each other. Also, tear strip includes a grasping tab 31 at an end thereof. However, unlike the prior art tear strip, the tear strip 30 is defined by perforated tear lines 10 that are identical to the tear lines 10 depicted in figure 2.

Figure 6 illustrates a tear strip 40 which is the same as the tear strip except that the tear strip 40 is defined by perforated tear lines 20 that are identical to Ic) 7

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the tear lines 20 depicted in figure 3.

Figure 7 illustrates a tear strip 50 which differs from the tear strips 30, 40 in that it is defined by two perforated tear lines 51 which are different to the tear lines if 10, 20 which define the tear strips 30, 40. The trailing portion 13 of each cut 11 of each tear line 51 includes a first sub-portion 52 which extends from an end of the 0 leading portion 12 of the cut 11 and which is parallel to the nominal tear line 14. The trailing portion 13 of each cut 11 of each tear line 51 also includes a second subportion 53 which is inclined with respect to the first sub-portion 52. The second subn portion 53 extends from an end of the first sub-portion 52 which is opposite to the end to of the first sub-portion 52 which the leading portion 12 extends from. The second sub-portion 53 terminates on the nominal tear line 14. Both the first sub-portion 52 and the second sub-portion 53 are straight The perforated tear lines 10, 20, 51 and tear strips 30, 40, 50 are formed in the tearable material along which they extend by a suitable die such as a planar stamping-type die or a rotating die.

Throughout the specification and claims, unless the context requires otherwise, the term "comprise", or variations such as "comprises" or "comprising", will be understood to apply the inclusion of the stated integer or group of integers but not the exclusion of any other integer or group of integers.

Throughout the specification and claims (if any), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms.

It will be appreciated by those skilled in the art that variations and modifications to the invention described therein will be apparent without departing from the spirit and scope thereof. The variations and modifications as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.

Claims (22)

1. According to a first aspect of the present invention there is provided a perforated tear line extending along a section of tearable material, the perforated tear ti) line comprising a plurality of cuts in the material that are spaced apart from each other and that are arranged in a line, wherein each of the cuts includes a leading 00 portion extending across a nominal tear line, and a trailing portion extending I rearwardly from the leading portion and terminating on the nominal tear line. o

2. The perforated tear line of claim 1, wherein the cuts are generally sawtooth- r shaped.

3. The perforated tear line of any one of the preceding claims, wherein the leading portion is straight.

4. The perforated tear line of claim I or 2, wherein the leading portion is curved.

The perforated tear line of any one of the preceding claims, wherein the leading portion is inclined towards the trailing portion.

6. The perforated tear line of any one of the preceding claims, wherein the trailing portion is straight.

7. The perforated tear line of any one of claims I to.5, wherein the trailing portion is curved.

8. The perforated tear line of any one of claims 1 to 5, wherein the trailing portion further comprises a first sub-portion extending from the leading portion in parallel with the nominal tear line, and a second sub-portion extending from and inclined with respect to the first sub-portion such that the second sub-portion terminates on the nominal tear line.

9. The perforated tear line of any one of the preceding claims, wherein the nominal tear line intersects midway along the length of the leading portion.

A tear strip extending along a section of tearable material, the tear strip being defined by a pair of laterally separated perforated tear lines that each comprise a plurality of cuts in the material that are spaced apart from each other and that are arranged in a line, wherein each of the cuts includes a leading portion extending across a nominal tear line, and a trailing portion extending rearwardly from the leading portion and terminating on the nominal tear line. tt') 9 0 o

11. The tear strip of claim 10, wherein the cuts are generally sawtooth-shaped.

12. The tear strip of claim 10 or 11, wherein the leading portion is straight.

13. The tear strip of claim 10 or 11, wherein the leading portion is curved.

In14. The tear strip of any one of claims 10 to 13, wherein the leading portion is inclined towards the trailing portion. 0

15. The tear strip of any one of claims 10 to 14, wherein the trailing portion is Istraight.

16. The tear strip of any one of claims 10 to 14, wherein the trailing portion is I curved.

17. The tear strip of any one of claims 10 to 14, wherein the trailing portion further comprises a first sub-portion extending from the leading portion in parallel with the nominal tear line, and a second sub-portion extending from and inclined with respect to the first sub-portion such that the second sub-portion terminates on the nominal tear line.

18. The tear strip of any one of claims 10 to 17, wherein the nominal tear line intersects midway along the length of the leading portion.

19. The tear strip of any one of claims 10 to 18, wherein the perforated tear lines are parallel to each other.

The tear strip of any one of claims 10 to 19, wherein the perforated tear lines are identical to each other.

21. A perforated tear line extending along a section of tearable material, the perforated tear line being substantially as herein described with reference to figure 2 or 3 of the illustrations.

22. A tear strip extending along a section of tearable material, the tear strip being substantially as herein described with reference to figure 5, 6, or 7 of the illustrations. DATED this 25 th day of May 2005 AMCOR LIMITED By its Patent Attorneys CULLEN CO.