AU768863B2

AU768863B2 - Pull cord for coverings for architectural openings and method of making same

Info

Publication number: AU768863B2
Application number: AU56565/00A
Authority: AU
Inventors: Klas Ture Ivarsson; Kenneth W. Witherell
Original assignee: Turnils AB
Current assignee: Turnils AB
Priority date: 1999-09-07
Filing date: 2000-09-07
Publication date: 2004-01-08
Anticipated expiration: 2020-09-07
Also published as: AU5656500A; EP1083254A2; US20020104626A1; EP1083254A3

Description

-1-

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventors: Address for Service: Turnils A.B.

Kenneth W. Witherell and Klas Ture Ivarsson BALDWIN SHELSTON WATERS MARGARET STREET SYDNEY NSW 2000 'PULL CORD FOR COVERINGS FOR ARCHITECTURAL OPENINGS AND METHOD OF MAKING SAME' Invention Title: The following statement is a full description of this invention, including the best method of performing it known to me/us:- File: 28773AUP00 -la- PULL CORD FOR COVERINGS FOR ARCHITECTURAL OPENINGS AND METHOD OF MAKING SAME BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to pull cords used in coverings for architectural openings and more particularly to a braided pull cord and the method of making the cord.

Description of the Relevant Art Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common 15 general knowledge in the field.

th eMost coverings for architectural openings, such as windows, doors, archways and o the like, have an operating mechanism that is controlled by a flexible element that can be a fiber based cord, a beaded chain or the like. The control cord and the like typically depends from one end of a headrail for the covering and extends into the headrail through a friction brake and subsequently through carrier elements and around a plurality of pulleys and the like that are associated with the operation of the covering.

As a result, the control cord is frictionally engaged at a number of locations and, depending upon the frequency of operation of the covering and the abrasiveness of the elements with which the cord comes into contact, the control elements can easily 25 deteriorate.

In the case of fiber based cords, the abrasion caused by the various elements in which it comes into contact, causes rapid deterioration of the cords. Cords that have deteriorated have to be replaced and many operating cords in coverings for architectural openings are replaced on an annual basis. When the covering has been warranted, the replacement cost is borne by the manufacturer and, accordingly, the quality and longevity of control cords is a significant economic factor in the covering industry.

A typical fiber based cord used in coverings for architectural openings is braided from polyester fibers, with the cords typically including sixteen carrier fibers. After braiding of the cord, it is heat treated and wound on storage rolls before being incorporated into a covering product. The braid is relatively tight.

In trying to resolve the problem of rapidly deteriorating operating cords, applicants initially looked to the hardware of the system to remove any abrasive surfaces across which the cord had to pass. By redesigning various plastic molded parts and the parting lines in the plastic molds for the parts, the wear cycle was improved. The redesigned components were later coated with low firiction materials such as Teflon® or zinc to reduce abrasion, but only marginal improvement was noticed. Further, the coatings tended to wear off over time and with exposure to UV light. Applicants then decided that the focus for improving the wear cycle of operating cords needed to be on the cord itself and it is to this end that the present invention has been made.

SUMMARY OF THE INVENTION According to a first aspect, the present invention provides a covering for an architectural opening comprising in combination: covering means for selectively covering and uncovering the architectural opening by extension and retraction of said covering means; and an operating mechanism mounted adjacent to said architectural opening and being operatively associated with said covering means for extending and retracting said covering means; said mechanism including: i) a braided control cord that was braided from a yam under high tension and was chemically coated while under high tension, and ii) operative elements that are frictionally engaged, with reduced abrasion, with said braided control cord.

According to a second aspect, the present invention provides a method of reducing abrasion between a control cord of a covering for an architectural opening and operative "elements of an operating mechanism in the covering that are frictionally engaged with said control cord, comprising the steps of: braiding the control cord from a yarn under 25 high tension, and then chemically coating said control cord under high tension.

According to a third aspect, the present invention provides a method of making a control cord for use in coverings for architectural openings comprising the steps of: providing a spool of high tensile strength yam with the yam having low abrasion characteristics; removing the yarn from the spool and passing it through a tensioning device; wrapping the yam under tension on bobbins; placing the bobbins in a braiding apparatus from which an eight-carrier braid is made, and passing the braided cord through a treatment apparatus where a coating of urethane is applied to the braided cord and the cord is dried and heat cured.

According to a fourth aspect, the present invention provides a cord for use in a covering for an architectural opening made from the steps of: -3providing a spool of high tensile strength yarn with the yam having low abrasion characteristics, removing the yarn from the spool and passing it through a tensioning device, wrapping the yam under tension on bobbins, placing the bobbins in a braiding apparatus from which an eight-carrier braid is made, and passing the braided cord through a treatment apparatus where a coating of urethane is applied to the braided cord and the cord is dried and heat cured.

Unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an S 15 inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

Other aspects, features and details of the present invention can be more completely understood by reference to the following detailed description of a preferred embodiment, "taken in conjunction with the drawings and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram illustrating the steps in the process of making the cord in accordance with the present invention.

Fig. 2 is a fragmentary diagrammatic isometric view showing yam from which the cord will be braided being passed from supply spools under tension to bobbins.

25 Fig. 3 is a fragmentary isometric illustrating the bobbins carrying the yarns under tension and being positioned in a braiding apparatus and with the braided cord being wrapped on a storage spool.

Fig. 4 is a diagrammatic view showing yarn from storage spools being passed through a two-stage process for coating the yams with urethane and heat curing the urethane on the yarn before accumulating the yarns on storage spools.

Fig. 5 is a fragmentary elevation showing the braided cord in accordance with the present invention.

Fig. 6 is a diagrammatic elevation showing a prior art braided cord.

DESCRIPTION OF THE PREFERRED EMBODIMENT The cord of the present invention is preferably made from high tensile strength fibers with low abrasion characteristics, such as polyethylene fibers. The fibers are preferably braided in an eight-carrier braid that is wound under very high tension and ultimately finished with a urethane coating that is heat cured. The resultant product has 3a provided a wear cycle of many times that achieved with state-of-the-art cords thereby almost removing the problem of manufacturers in having to record coverings for architectural openings. In accordance with one embodiment of the method for making the eight-carrier braid, high tensile strength fibers with low abrasion, such as might be polyethylene fibers, are wound under high tension onto yam bobbins and eight of the yam bobbins are then utilized in a conventional braiding apparatus to braid the cord.

The braided cord is held under tension and passed through a two-stage heat setting process wherein a urethane coating is applied to the braided cord and the coating is heat cured in the final stage. After the second stage of heating, the cord is wound onto spools for storage until they are strung into coverings for architectural openings.

The method of making a braided control cord for use in coverings for architectural .openings in accordance with the present invention is illustrated in a block diagram in o.

Fig. 1. It will be appreciated that fibers or yams from which the cord is to be braided are first unwound from spools on which they are supplied and then wound under high tension onto bobbins. From the bobbins, eight yams are braided into a cord also under high tension and the braided cord is subsequently wound on a transfer spool. The cords are unwound from the transfer spools under tension and fed into a treating apparatus where they are coated with urethane and immediately heat cured in a two-stage process I so that the urethane coating is dried and fully cured on the braided cords. After the coating has been heat cured, the yam is stored on storage spools from which it can be removed when incorporating the cord into an operating mechanism for a covering for architectural openings.

With reference to Fig. 2, a device 10 for unwinding yam 12 from preformed spools 14 of yam is shown in series with a conventional tensioning apparatus 16 for the yarns and a conventional apparatus 18 for wrapping the yams on bobbins 20 under tension. To provide even greater tension in the yam than is provided by the conventional tensioning apparatus 16, the yams are passed through an additional but conventional washer tensioner 21 before they are received by the tensioning apparatus 16. The device 10 for unwinding the yam from the spools 14 can be seen to include a plurality of spindles 22 on which the spools 12 of yam are disposed and the yam is threaded through low friction ceramic guides 24 associated with each spool so that they can be passed individually to the washer tensioner 21 before passing on to the tensioning apparatus 16. In the tensioning apparatus, they are tensioned in a conventional manner with washer tensioners 25 so that the yars 12 when passed down to the bobbins 20 are fed to and wound on the bobbins under tension. Each of the devices and apparatuses 10, 16 and 18 are conventional items such as manufactured by Ratera of Spain.

The yams 12 have a high tensile strength in the range of 28-35 grams/denier, and grams/denier, and have low coefficients of friction, low abrasion characteristics and are durable from a flex fatigue standpoint. Examples of yams that would be suitable for this purpose are Kevlar manufactured byDuPont in the United States, Nomex manufactured by DuPont, Twaron manufactured byAkzo of The Netherlands, Dyneema manufactured byDSM of Holland or Spectra manufactured by the Allied Signal Division of Honeywell, Inc., Petersburg, Virginia. The yamrn or fibers are preferably polyethyiene. The tension under which the yams 12 are wound on the bobbins 20 is preferablyin the range of 115 to 140 grams and desirably 120 grams.

Looking next at Fig. 3, the bobbins 20 with the yam 12 wound thereon under tension, 15 are placed in a braiding apparatus 26 of a conventional type such as of the type manufactured by Ratera of Spain. In the preferred embodiment of the invention, eight yams are braided into a cord 27 and after braiding, wound onto a transfer spool 28. The denier of the yams is preferably in the range of 275 to 375, which is greater than the denier of yars typically braided into control cords, as can be evidenced by reference to Figs. 5 and 6, with Fig. 5 being a cord braided in 20 accordance with the present invention and Fig. 6 a prior art braided cord.

The transfer rolls of braided cord are then operatively connected to a treatment apparatus 30 (Fig. 4) for final treatment of the cord. Each transfer spool 28 of cord is rotatably mounted on a bracket 33 on the upstream end of the apparatus 30 so that the cord can be fed into and through the treatment apparatus under tension via a conventional tensioner 34. The tension in the cord is preferably in the range of 150- 20 0 g, with 150 grams- being ideal. In the apparatus, 30 the braided cord 27 is first fed through a chamber 36 where the cord is padded with a urethane coating that is applied to the cord. The chamber 36 is fed from a urethane reservoir 37. Byway of example, the coating might be either sprayed onto the cord or the cord might be drawn through a bath of the urethane in order to apply the desired coating to the cord.

The latter is preferred. Immediately after the cord is coated with the urethane, it is passed through a heating chamber or oven 38 where the urethane is dried. The temperature in the heating chamber 38 is preferably in the range of 120-140 0 C even though temperatures outside that range would work as it would primarily affect the drying time. Subsequent thereto, the cord is passed through another heating chamber 39 where the urethane is cured. The temperature in the curing chamber 39 is preferably in the range of 1001120 C even though, again, temperatures outside that range would work as the temperature primarily affects the curing time. The total time for drying and curing should ideally be in the range of 60-120 seconds, with 90 seconds being desired. After the cord 27 has been padded with the urethane coating and cured, the final braided cord is wrapped onto a storage spool 40 that is rotatably mounted on brackets 42 at the downstream end of the apparatus 34. When a predetermined supply of the braided cord 27 is wound onto the storage spool 40, the spool is removed and retained for later use in the assembly of a covering for an architectural opening. The apparatus 30 for treating the cord with a urethane solution and curing the cord is conventional and may be of the type manufactured:by Andersson Mek of Sweden. The urethane solution is a mixture of urethane and water in a concentration of 10% urethane by volume. The urethane is miscible in/with water and 15 preferablyitself comes from the chemical family of polyester, polyether polyurethane dispersions and can come from various sources but a urethane marketed under the designation Baypret DLV Dispersion Corporation byBayer Corporation of Pittsburgh, Pennsylvania, has been found suitable for the cord of the present invention.

A cord formed in accordance with the present invention and as illustrated in Fig. 5, has 20 been found to provide a wear cycle that is approximately ten times that of conventional cords "that are presentlyin use.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made byway of example, and changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.

Claims

1. A covering for an architectural opening comprising in combination: covering means for selectively covering and uncovering the architectural opening by extension and retraction of said covering means; and an operating mechanism mounted adjacent to said architectural opening and being operatively associated with said covering means for extending and retracting said covering means; said mechanism including: i) a braided control cord that was braided from a yam under high tension and was chemically coated while under high tension, and ii) operative elements that are frictionally engaged, with reduced abrasion, with said braided control cord.

2. The covering of claim 1 wherein said yarn is wound on bobbins under a tension of 115 to 140 grams prior to being braided into said braided control cord.

3. The covering of claim 1 or 2 wherein said yarn is a polyethylene yarn.

4. The covering of any one of claims 1-3 wherein said braided control cord was chemically coated with a urethane solution.

5. The covering of claim 4 wherein said braided control cord was placed under a tension of 150 to 200 grams and then chemically coated with said urethane solution prior to frictionally engaging said operative elements.

6. The covering of claim 4 or 5 wherein said braided control cord was coated with a mixture of urethane and water, then dried and cured prior to frictionally engaging said operative elements.

S•7. The covering of any one of claims 4-6 wherein said urethane solution is a solution of a polyester, polyether urethane.

8. The covering of any one of claims 1-7 wherein said yarn has a tensile strength of 28 to 35 grams/denier and a denier of 275 to 375.

9. A method of reducing abrasion between a control cord of a covering for an architectural opening and operative elements of an operating mechanism in the covering that are frictionally engaged with said control cord, comprising the steps of: braiding the control cord from a yam under high tension, and then chemically coating said control cord under high tension.

10. The method of claim 9 wherein said yarn is wound on bobbins under a tension of 115 to 140 grams prior to being braided into said control cord.

11. The method of claim 9 or 10 wherein said yam is a polyethylene yarn.

12. The method of any one of claims 9-11 wherein said control cord is chemically coated with a urethane solution.

13. The method of claim 12 wherein said control cord is placed under a tension of 150 to 200 grams and then chemically coated with said urethane solution prior to frictionally engaging said operative elements.

14. The method of claim 12 or 13 wherein said control cord is coated with a mixture of °ee. urethane and water, then dried and cured prior to frictionally engaging said operative 20 elements.

The method of any one of claims 12-14 wherein said urethane solution is a solution of a polyester, polyether urethane.

16. The method of any one of claims 9-15 wherein said yam has a tensile strength of 28 to 35 grams/denier and a denier of 275 to 375. 25

17. A covering for an architectural opening substantially as herein described with :reference to any one of the embodiments of the invention illustrated in the accompanying drawings.

18. A method of reducing abrasion between a control cord and an operational mechanism substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings. DATED this 5th day of November, 2003 BALDWIN SHELSTON WATERS Attorneys for: TURNILS A.B.