GB2299504A

GB2299504A - Articles of bedding

Info

Publication number: GB2299504A
Application number: GB9607097A
Authority: GB
Inventors: Ronald Ernest Sandall
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-04-03
Filing date: 1996-04-03
Publication date: 1996-10-09
Anticipated expiration: 2016-04-03
Also published as: GB9607097D0; GB2299504B; GB9506871D0

Abstract

A waterproof and gas-tight duvet or pillow comprises a cover of impermeable, flexible plastics material 14 and an interior filled with a single plastics fibre insert 16. Through ventilation holes 17 are formed by a welding-cut technique which connects together the upper and lower layers of the cover at spaced locations over the duvet and also locates the insert within the cover. In one embodiment, the insert itself is sandwiched between the upper and lower layer and welded and cut, but in another embodiment holes are pre-formed in the insert before it is introduced into the cover, and the upper and lower layers of the cover are welded through said holes.

Description

Articles of Bedding This invention relates to articles of bedding and methods of producing such bedding.

In my earlier U.K. Patent No. 2 074 021B, I disclose a duvet made up of a gas tight plastics cover with through ventilation holes. Such a duvet is especially beneficial in hospitals, nursing homes, etc, as it allows the duvet to be easily cleaned and thoroughly sterilised, simply by wiping or spraying the surfaces with an antiseptic or biocidal liquid, and the internal filling is protected from contamination.

The usual method of production of such duvets is to first produce the gas-tight cover of the duvet from two sheets of flexible plastics materials such as polyvinyl chloride (p.v.c.), or similar, using high-frequency or ultrasound welding techniques. The sheets of plastic are welded together along the two side edges of the cover leaving the top and bottom edges of the cover open and unwelded. At the same time, a number of ventilation holes are formed in both sheets by welding and then perforating them so that the lines of sealed ventilation holes interconnecting the sheets are formed which divide the cover into a number of pockets to accommodate the insulating material.

Secondly individual strips of insulating material are inserted into the pockets formed in the cover between the lines of ventilation holes. This involves the production and handling of a number of separate pieces of insulation, a time-consuming and costly process. After the strips of insulation have all been positioned in the pockets, the top and bottom edges of the cover are welded together to seal the interior of the duvet and render it gas-tight and waterproof.

In U.K. Published Application No. 2 268 878A (Karomed) a mat of thermally insulating material is located in a plastics cover and is attached internally to the cover by means of internal flaps, but this duvet makes no provision for through ventilation and therefore will be uncomfortable in use as water vapour will not be able to pass through the duvet and so will be trapped next to the user.

It will be seen that previously the assembly of waterproof duvets has been troublesome and that a variety of measures have been tried over the years but until now the production has been time consuming.

I have now found that it is possible to provide many if not all of the advantages of my earlier duvet with considerably reduced complexity. I have developed a method which allows a single insert of thermally insulating material to be introduced directly between the sheet elements of the bedding article and then securely located therebetween, whilst still providing through ventilation.

Accordingly, in one aspect, this invention provides a method of producing an article of bedding, which comprises the steps of introducing an insert of thermally insulating material between two sheet elements of substantially impermeable material making up a cover, and connecting said elements together at a plurality of locations spaced across said insert thereby to secure or restrict movement of said insert with respect to said cover.

Preferably, through ventilation holes are also formed at said locations. The sheet elements are preferably made of a thermoplastic material such as polyvinyl chloride.

The insert preferably comprises structured fibres such as a mat or felt, or other shape-retaining collection thereof. The insert preferably comprises plastics fibres, for example polyester fibres.

Where polyvinyl chloride is used for the cover, and the insert comprises plastics fibres, the fibre material is preferably chloride enriched whereby the melting and/or welding temperatures of the sheet material and the insert are compatible, ideally within 20"C.

The sheet elements are preferably connected together at said spaced locations by heat and welding, e.g. by high frequency welding. The sheet elements may be welded together and around through said insert, or they may be connected together at said spaced locations through preformed holes provided in said insert. In this instance to facilitate production the part-formed article, comprising the two sheet elements and the insert, may be exposed to a strong light source of sufficient strength to allow the positions of the pre-formed holes in the insert to be determined by an operator in preparation for said connecting step.

Said through ventilation holes are formed substantially simultaneously with connection of said sheet elements, for example in a cut-welding step, and advantageously formed to provide a substantially air-tight seal.

The article may be completed by connecting said sheet elements to each other around their peripheries to provide a substantially air tight seal.

In another aspect, the invention extends to an article of bedding comprising a substantially impermeable cover of sheet material enclosing an insert of thermally insulating material, in which said insert is secured within, or restricted against movement with respect to, the cover by interconnections between opposed portions of the sheet material at a plurality of locations spaced across said insert.

Said article preferably includes at said locations through ventilation holes connecting opposite sides of said article.

Whilst the invention has been described above, it extends to any inventive combination of the features set out above or in the following description.

The invention may be performed in various ways and two embodiments thereof will now be described in detail, reference being made to the accompanying drawings, in which:- Figure 1 is a plan view of a first embodiment of duvet in accordance with this invention; Figure 2 is a detailed cross-sectional view in the vicinity of a through ventilation hole in the embodiment of Figure 1.

Figure 3 is a plan view of a second embodiment of duvet in accordance with the invention; Figure 4 is a detailed cross-sectioned view in the vicinity of a through ventilation hole in the embodiment 8 Figure 3, and Figure 5 is a schematic view of a welding jig for use in manufacture of the duvet of Figure 3.

Referring initially to Figures 1 and 2, the first embodiment of duvet 10 comprises a water- and air-tight cover 12 made by heat welding two rectangular sheets 14 of flexible p.v.c. plastics material along the two side (longer) edges, to form an envelope open at both ends. A suitable plastics material is a p.v.c. sheet material 0.0065" (0.165mm) thick sold under product reference D22MB by Forbo CP Limited.

A single mat 16 of thermally insulating material comprising polyester fibres, such as those sold for filling duvets and pillows etc by British Vita, is introduced into the envelope through one end. A high frequency welding cut technique is then used to weld together the sheets through the insulating material and simultaneously to remove a portion in the middle of the weld to form a through ventilation hole 17. Typically, the welding operation is carried out at a temperature of 140 to 150"C, a pressure of 500 psi (3.45 MPa), and for a period of 3 to 7 seconds. I have found that these conditions are sufficient to consolidate the three layers and to create a substantially airtight seal to prevent leakage of gas between the cut edges of the ventilation holes into the interior of the duvet.I believe that these conditions create sufficient local plastic deformation of the sheet material and/or the fibres to prevent leakage paths between the polyester fibres and the p.v.c. sheet material and, where the fibres are hollow, through the fibres. If required, the chloride content of the polyester fibres may be increased to facilitate consolidation of the three layers. The production of the duvet is then completed by heat welding the two sheets 14 along the top and bottom edges to produce a water- and air- tight enclosure.

Referring now to Figure 3, the second embodiment of duvet 20 is made by pre-forming an array of slightly oversize holes 23 in a single insert 22 of thermally insulating material, which may again be a mat of polyester fibres. The positions of the holes correspond to the positions of the through ventilation holes in the finished duvet.

As previously, a water- and air- tight cover 24 is made by heat welding two rectangular sheets 26 of flexible thermoplastic material such as p.v.c. along their two longer edges to form an envelope into which the insert 22 is introduced. The duvet is then subjected to a welding cut technique at each of the holes in the insert to weld the sheets together (here without the insert material sandwiched between them) and to form a through ventilation hole 28, have been formed, the product is finished by welding the sheets along their top and bottom edges, to produce a watertight and airtight enclosure.

The step of producing the welds and ventilation holes in the second embodiment is considerably assisted by the jig shown in Figure 5. The jig comprises a heated punch and die 40, 42 respectively, and a lamp 44 shining upwardly so that the operator can determine where to apply the weld, without trapping insulating material adjacent the pre-formed holes.

In both these embodiments, the welding and cutting at each location fulfils three functions, namely to interconnect. the upper and lower sheets, to provide a through ventilation hole, and to prevent or restrict the movement of the insert within the cover. Also, the embodiments eliminate the necessity to produce, store and handle a large number of strips of insulating material, it reduces the time to introduce the insulating insert, thereby reducing production costs considerably. Furthermore, the insulating insert is securely located in the cover and yet the restrictions to flow of air within the duvet are reduced. Also, the removal of line welds or stitching running the length of the duvet reduces the "cold" spots.

Although we have specifically referred to duvets, the invention extends to other articles of bedding such as pillows. We refer to the cover being made up of two sheet elements and it should be appreciated that we do not exclude the possibility of both sheet elements comprising a single piece of material folded over to provide two sheet elements.

Claims

1. A method of producing an article of bedding, which comprises the steps of introducing an insert of thermally insulating material between two sheet elements of substantially impermeable material making up a cover, and connecting said elements together at a plurality of locations spaced across said insert thereby to secure or restrict movement of said insert with respect to said cover.

2. A method according to Claim 1, wherein the sheet elements are made of a thermoplastic material.

3. A method according to Claim 2, wherein said sheet elements are made of polyvinyl chloride.

4. A method according to any preceding Claim, wherein said insert comprises polyester fibres.

5. A method according to Claim 4 when dependent on Claim 3, wherein said polyester material is chloride enriched whereby the melting and/or welding temperatures of the sheet material and the insert are compatible.

6. A method according to any preceding Claim, wherein said sheet elements are connected together at said spaced locations by heat welding.

7. A method according to Claim 6, wherein said sheet elements are welded together through said insert.

8. A method according to Claim 6, wherein said sheet elements are connected together at said spaced locations through pre-formed holes provided in said insert.

9. A method according to Claim 8, wherein the part formed article, comprising the two sheet elements and the insert, is exposed to a strong light source of sufficient strength to allow the positions of the pre-formed holes in the insert to be determined in preparation for said connecting step.

10. A method according to any preceding Claim, which includes forming through ventilation holes at said spaced locations.

11. A method according to Claim 10, wherein said through ventilation holes are formed substantially simultaneously with connection of said sheet elements, for example in a.cut-welding step.

12. A method according to Claim 10 or 11, wherein said through ventilation holes are formed to provide a substantially air-tight seal.

13. A method according to any preceding Claim, wherein said sheet elements are also connected to each other around their peripheries to provide a substantially air tight seal.

14. An article of bedding comprising a substantially impermeable cover of sheet material enclosing an insert of thermally insulating material, in which said insert is secured within, or restricted against movement with respect to, the cover by interconnections between opposed portions of the sheet material at a plurality of locations spaced across said insert.

15. An article according to Claim 14, wherein said article includes at said locations through ventilation holes connecting opposite sides of said article.

16. A method substantially as hereinbefore described with reference to the accompanying drawings.

17. An article of bedding substantially as hereinbefore described with reference to, and as illustrated in, any of the accompanying drawings.