WO1990003754A1

WO1990003754A1 - Coaster

Info

Publication number: WO1990003754A1
Application number: PCT/AU1989/000441
Authority: WO
Inventors: Joseph Robin Orbell
Original assignee: Baldwin Holdings Pty Ltd.
Priority date: 1988-10-10
Filing date: 1989-10-10
Publication date: 1990-04-19

Abstract

A coaster (10) made from an absorbent material having projections (18) extending from a major surface (14) to support a vessel in spaced relation to the major surface (14) such that a vacuum cannot form between the vessel and the major surface (14).

Description

TITLE COASTER DESCRIPTION The present invention relates to a coaster. FIELD OF THE INVENTION

Coasters are mats placed on a table top or other smooth surface so that vessels containing liquid can be placed thereon. When the vessel contains a cold liquid condensation can form on the outer surface of the vessel. Typically, this condensation flows down the outer surface of the vessel and would form a wet patch on the smooth surface if it were not for the presence of the coaster. With previously known conventional coasters the moisture can form a seal around the lower end of the vessel. Thus, when the vessel is lifted by a user, a vacuum can be created between the lower end of the vessel and the coaster. This can cause the coaster to adhere to the vessel so that the coaster is lifted with the vessel. This can be very disconcerting for the user arid cause him or her to spill the liquid in the vessel and moisture from the condensation referred to above can be spilled off the coaster. Also, the adhered coaster may fall off causing damage and/or disorder particularly if the coaster contacts food or drink, such as if the coaster falls into a jug of liquid or a plate of soup.

A conventional coaster is generally flat and composed of a relatively thick mat of recycled paper pulp which renders the mat absorbent to moisture. However, a side effect is that once moisture is absorbed, the mat swells, becomes unsightly and cannot be used again. Thus, a conventional coaster has a very limited life. Further, "SUch thick mat type coasters are not suitable for printing if a high degree of definition is desired. Ink used in printiϊig permeates the mat and diffuses laterally. As a result, fine details become blurred and indistinct and colours at borders merge and obscure each other. Additionally, since the mat absorbs the ink to a certain depth, the ink is sparsely distributed and is not as vibrant or intense as compared to printing on normal paper.

Coasters having a plurality of projections on their upper surface are known per se. A typical example is U S Patent No. 3 583 664 which shows an antidrip saucer having a plurality of upwardly projecting ribs. Another example is French Patent No. 520752 which discloses a coaster having a plurality of upwardly pointing projections. There have also been other attempts to alleviate the problem of coaster to vessel adhesion. Australian Patent NO. 285710 discloses a composite coaster having a bottom member, a tumbler receiving member and a moisture absorbent member sandwiched therebetween. U S Patent No. 2893163 discloses a coaster having a plurality of ribs and a circumferential band, both ribs and the band being made from- a foam plastics or a sponge rubber. U S Patent No. 2652703 shows a similar coaster to that -of Australian

Patent No. 2*5710 in which an absorbent layer is sandwiched in a comβosite coaster construction. Embossing of thin paper sheets is relatively straight forward and^*£nown. Generally, such embossing can produce very fine and intricate designs with almost no restriction as to shape or size. However, embossing of cardboard, whilst also well known, is subject to many more restrictions. A typical example of cardboard embossing is corrugated cardboard. A closer examination of the corrugations will reveal that there is cracking and rupturing of the surface of the cardboard. This is acceptable where the end product has no aesthetic function to fulfil. Further, such corrugations are generally broad in comparison to their height. If narrow, high corrugations were attempted to be formed, the problem of cracking and rupturing would be exacerbated. Avoidance of cracking and rupturing in embossing cardboard is important where the surface with raised projections has to have an aesthetic appeal. Any visible cracks or ruptures break the surface and are unsightly. In particular, cracking or rupturing caused by embossing of a printed surface is unsightly. SUMMARY OF THE INVENTION

The present invention provides a coaster made from absorbent material and having projections substantially free from cracking. In accordance with one aspect of the present invention there is provided a coaster made form an absorbent material and comprising a major surface which is intended to be uppermost and generally horizontal when the coaster is resting on a flat, horizontal surface, and wherein there is a plurality of projections extending from the major surface, the projections being substantially free form cracking and being intended to support a vessel in spaced relation to the major surface, said projections being so arranged that when a vessel is resting on them there is a region between the vessel and the major surface which is not sealed such that a vacuum cannot form therein. Preferably, the absorbent material is composite absorbent paper board. The coaster of the present invention may be formed by embossing using a die.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a plan view of a coaster in accordance with the present invention;

Figure 2 is a section along the line B-B of Figure 1; Figure 3 is a section along the line A-A of Figure 1; and Figure.4 is a schematic section to an enlarged scale showing a rib as seen in Figure 3.

DESCRIPTION OF THE INVENTION In Figures 1 and 2 there is shown an embossed coaster 10, manufactured as described hereinafter composed of a water absorbent material, typically composite absorbent paper board, and comprising a generally flat central portion having a generally flat lower surface 12 and a generally flat upper surface 14 forming a major surface which is intended to be uppermost and generally horizontal when the coaster is resting on a flat horizontal surface. The composite absorbent paper is composed of interwoven fibres and is to be distinguished from laminates which are commonly used in the production of coasters. The central portion has an outwardly extending peripheral raised rim 16, the rim 16 being inclined upwardly away from the central portion at about 10 to 30 - degrees to the central portion. Further, the central portion has formed in it a plurality of projections which are raised, elongated ribs 18. The ribs 18 extend radially outwardly from a mid point of the central portion and are angularly spaced from one another.

The shape of the ribs 18 can be seen more clearly in Figures 2 and 3. The ribs 18 extend part way towards the mid point and are all separated from one another. Typically, the ribs 18 are about 1mm high and 3mm wide. As can best be seen in Figure 2, each rib 18 is preferably smoothly curved at its inner end 19. As can be seen in Figure 3, each rib 18 preferably has a generally arcuate profile in a cross section. To manufacture a coaster 10 in accordance with the present invention, a mat of absorbent material, which may be from 0.5 to 5mm, such as from 1 to 3mm, thick, may have print applied to the upper surface 14. Subsequently, the printed mat is typically placed between an embossing die comprising complementary male and female halves. The halves further comprise respective ridges and troughs to form the plurality of ribs 18 in the coaster 10. Each ridge and trough has a respective peak and valley which is curved or radiused to render the ribs 18 of the coaster 10 substantially free from cracking and rupturing. The die halves compress and emboss the mat, typically at a pressure of about 90 tons/in , and a coaster 10 in accordance with the present invention. is produced. Typically, the compression of the mat reduces the thickness thereof by about 0.5mm. Surprisingly, it is found that after such compression, the mat is still capable of absorbing moisture. If desired, a small amount of moisture may be applied to the upper surface of the mat prior to compression. This results in a harder rib 18 being formed upon compression. Preferably, the moisture is applied in the form of a spray especially a very fine mist spray which may be pulsed. It is found that the droplets of the spray penetrate the uppermost surface of the coaster and cause the uppermost surface to soften. This helps prevent cracking of the raised uppermost portion of the ribs 18. Further, when dry, the uppermost surface of the ribs 18 are more rigid and hard compared to when no spray is applied. Further, the die is preferably constructed to emboss and cut out each coaster simultaneously.

In Figure 4, the rib 18 is shown in greater detail. The rib 18 has a base 20 and a peak 22. As seen the rib 18 may be radiused at its base 20 adjacent the upper surface 14. The rib 18 is also radiused both internally and externally at its peak 22 which is spaced from the upper surface 14. Preferably, as shown in Figures 1 and 2 the ribs 18 project outwardly into engagement with the rim 16. This confers added rigidity to the rim 16. This is a preferred but not essential.feature because effective coasters are obtainable where the ribs 18 stop short of the rim 16. In use, the ribs 18 are arranged to support a vessel containing liquid, particularly cold liquid, in spaced relation from the upper surface 14 when the lower surface 12 is resting on a flat substantially horizontal smooth surface such as a table.

Further, the fact that the ribs 18 are separated from one another at their inner ends avoids the possibility of formation of a vacuum between the container and the coaster.

Still further, the fact that the lower surface 12 is generally flat may make it difficult to lift the coaster 10 from a flat smooth surface. However, the peripheral rim 16 enables the coaster 10 to be readily picked up if desired. Further, the peripheral rim 16 also retains condensed moisture which has collected on the surface 14. The coaster 10 of the present invention can be made in any convenient shape. The coaster 10 shown in Figure 1 is circular but it could equally well be square or any other shape.

The ribs 18 preferably have a width of from 2 to 4m such as about 3mm and a height of from 0.8 to 1.0mm such as about 0.8mm. The external radius of the peak is preferably 1.5 to 2mm such as about 1.5mm. The internal radius of the peak 22 is preferably from 0.75 to 1mm such as about 0.75mm. Further, the external radius of the base 20 on the surface 14 is preferably in the range from 1 to 2mm such as about 1.5mm. The number of ribs 18 preferably does not exceed 3- in 180° of arc and it is preferred that each coaste* not have more than 5 ribs 18. . Further, the inner end of each rib 18 is preferably at least 15mm from the mid point of the coaster 10. The inner ends 19 of the ribs 18 are preferably curved as can be seen in Figure 2 because less stress is created on the coaster 10 during embossing compared to an angular end 19. Preferably, each rib 18 has a length no more than 60% of the distance from the mid point of a coaster to the periphery thereof.

With the preferred dimensions referred to above, it is found that the ribs 18 can be pushed up to a height more than the thickness of the compressed mat without breaking or cracking of the surface 14. The definition of print on the compressed coaster is better than that on a non compressed coaster. Also, the compression and embossing gives the coaster greater durability because it has greater resistance to warping. Modifications and variations such as would be apparent to a skilled addressee are deemed within the scope of the present invention.

Claims

1. A coaster characterised in that it is made from an absorbent material and comprising a major surface which is intended to be uppermost and generally horizontal when the coaster is resting on a flat, horizontal surface, and characterised in that there is a plurality of projections extending from the major surface, the projections being intended to support a vessel in spaced relation to the major surface, said projections being so arranged that when a vessel is resting on them there is a region between the vessel and the major surface which is not sealed such that a vacuum cannot form therein.

2. A coaster according to Claim 1, characterised in that the absorbent material is composite absorbent paper board.

3. A coaster according to Claim 1 or 2, characterised in that it has been produced by the use of a die.

4. A coaster according to any one of the preceding Claims, characterised in that the projections are elongated ribs.

5. A coaster according to Claim 4, characterised in that the ribs extend radially outwardly away from a mid point of the major surface and are angularly spaced from one another, and the ribs have inner ends which are spaced from the mid point and separated from one another.

6. A coaster according to Claim 5, characerised in that the inner end of each rib is smoothly curved.

7. A coaster according to Claim 5 or 6, characterised in that each rib has a width in the range from 2 to 4mm.

8. A coaster according to any one of Claims 5 to 7, characterised in that each rib has a height in the range from 0.8 to 1 mm.

9. A coaster according to any one of Claims 5 or 8, characterised in that each rib is of generally arcuate profile in cross section and is substantially free from cracking.

10. A coaster according to Claim 9, characterised in that each rib has a base adjacent the major surface and a peak remote from the major surface, the rib being radiused at the base thereof.

11. A coaster according to Claim 10, characterised in that each rib has a base with an external radius to the major surface in the range from 1 to 2mm.

12. A coaster according to any one of Claims 9 to 11, characterised in that each rib has a peak with an external radius of from 1.5 to 2 mm.

13. A coaster according to any one of Claims 9 to 12, characterised in that each rib has a peak with an internal radius of from 0.75 to 1 mm.

14. A coaster according to any one of Claims 5 to 13, characterised in that the inner end of each rib is at least 15 mm from the mid point of the major surface.

15. A coaster according to Claim 14, characterised in that each rib has a length no more than 60% of the distance from the mid point of the major surface to the periphery of the major surface.

16. A coaster according to any one of Claims 5 to 15, characterised in that there are no more than 5 ribs on the major surface.

17. A coaster according to Claim 16, characterised in that there are no more than 3 ribs in 180° of arc of the major surface.

18. A coaster according to any one of Claims 5 to 17, characterised in that a peripheral raised rim extends around the major surface, the raised rim being inclined upwardly away from the major surface.

19. A coaster according to Claim 18, characterised in that the rim is inclined upwardly at an angle in the range from 10 to 30° from the major surface.

20. A coaster according to Claim 18 or 19, characterised in that the ribs extend outwardly into engagement with the rim so as to confer added rigidity on the coaster.