WO1991015650A1

WO1991015650A1 - Pleated window covering and method of manufacturing same

Info

Publication number: WO1991015650A1
Application number: PCT/US1991/002257
Authority: WO
Inventors: Calvin H. Delano; Mario S. Colombo
Original assignee: Arquati, Inc.
Priority date: 1990-04-03
Filing date: 1991-04-02
Publication date: 1991-10-17
Also published as: AU7676391A

Abstract

A pleated window covering (24) is comprised of a transparent polyester film having a plurality of substantially uniform, V-shaped pleats (40) extending transversally with respect to a longitudinal axis of the window covering. The window covering is collapsible along the longitudinal axis by compressing the pleats together and is expandable along the longitudinal axis by pulling the pleats apart. Relatively flat sheets of the polyester film are pleated by pre-heating the sheets to a temperature within a range of approximately 76 °C-106 °C. The material is then pleated and is maintained within a temperature range of approximately 66 °C-103 °C for approximately 6-15 minutes. After the pleats are formed, pressure in a range of approximately 0.33 lbs./in.2-0.70 lbs./in.2 is applied to compress the pleats and hold them in the desired shape until the material has cooled sufficiently. The actual temperatures and pressures used in the manufacturing process will vary depending upon the thickness of the film material.

Description

Pleated Window Covering and Method of Manufacturing Same

Technical Field

This invention relates generally to window coverings and in particular to a new and improved pleated window covering.

Background Art

Window coverings, such as curtains, blinds and shades, are typically used to maintain privacy within a room and also to inhibit the flow of light and heat from the outside into the rooiii._f Curtains are used primarily for decoration, whereas shades and blinds are typically used for privacy and to inhibit the inflow of heat and light into the room. Of course, shades and blinds are often chosen for their decorative appeal as well.

One type of window shade is comprised of a relatively flat sheet of opaque material, which is wound around a roller mounted above the window. The roller is spring-loaded, so that the shade can be unwound from the roller by pulling down on the bottom of the shade and can be wound back onto the roller by pulling down on the bottom of the shade and then releasing the bottom to allow the spring-action to retract the shade. Another type of window shade is comprised of an opaque material, which is pleated to allow the shade to be folded accordion-style when the shade is pulled up by means of an operating cord or the like. The pleats will expand so that the shade becomes relatively flat when it is pulled down to cover the window. Pleated shades are preferred by many people because of their more decorative appearance than the aforementioned flat shades and also because many people find them easier and more convenient to operate than the flat shade and roller mechanism.

Pleated window shades are typically comprised of a woven fabric material, such as a polyester fabric. Pleats are formed in the fabric by heating relatively flat sheets of the material at temperatures up to 160'C to ensure that the fabric is pliable enough to pleat. A resin-based finish is typically applied to the fabric to allow it to withstand such high temperatures. The fabric material is opaque, so that the material will substantially reduce the amount of heat and light coming in through the window. A major disadvantage of opaque window coverings is that one cannot look through the window when the shade is pulled down.

Sheets of plastic film material have also been used to cover windows. Such materials include materials made of a polyester film, which is substantially transparent, but will effectively reduce glare and heat from incoming sunlight. Such materials have a distinct advantage over opaque window coverings because their transparency allows one to look through the window while the shade is in a closed position to reduce glare and heat from incoming sunlight. The plastic film material reduces glare by polarizing the incoming light and reduces heat flow into the room by reflecting and absorbing infrared energy from the sun's rays. Harmful ultraviolet rays are also reflected and absorbed by the material. Although transparent materials, such as polyester film, have distinct advantages as window coverings, heretofore there has been no effective way to form such materials into pleated window coverings . Transparent materials cannot withstand the high temperatures normally required to form the pleats and their smooth surface texture makes them unreceptive to the application of a heat-resistant finish. Disclosure of the Invention

These and other objects are accomplished in accordance with the present invention wherein a window covering is comprised of a flexible material, such as a polyester film, which substantially filters incoming sunlight to substantially reduce heat energy entering an indoor space and which is sufficiently transparent to permit visibility through the window to the outside. The material is creased at selected locations thereon to define a plurality of pleats extending transversely with respect to a longitudinal axis of the window covering. The window covering is collapsible along the longitudinal axis by compressing the pleats together and is expandable along the longitudinal axis by pulling the pleats apart. The pleats are preferably of uniform size and shape and have a substantially V-shaped cross- section, which allows the pleats to be selectively compressed together and pulled apart without deforming the shape of the window covering. In accordance with one feature of the invention, the window covering is manufactured by heating a relatively flat sheet of transparent plastic material to a temperature within a range of approximately 76'C-106'C and then creasing the material at selected locations thereon to define a plurality of substantially uniform, V-shaped pleats. After the material is pleated, it is maintained in a temperature range of approximately 66^*C-103'C for a predetermined period of time. Pressure in a range of approximately 0.33 lbs./in.² - 0.70 lbs./in.² is applied to maintain the desired shape of the pleats from the time the pleats are formed until they have cooled sufficiently.

The actual temperatures and pressures used in the manufacturing process will vary depending upon the thickness of the material. For example, when a polyester film material having thickness of approximately .002 inch (i.e., 2 mils) is used, the film will be pre-heated to a temperature of approximately 76^*C and then will be maintained at a temperature of approximately 66^*C -73^*C for a predetermined period of time (6 - 15 minutes) after pleating. The pressure applied to the pleats will be approximately 0.35 lbs./in.². If, however, the thickness of the film is on the order of 6 mils, the film will be pre-heated to a temperature of approximately 106"C and will be maintained at a temperature of approximately 96^*C - 103^*C for a predetermined period of time (6 - 15 minutes) after the pleats are formed. The pressure applied to the pleats will be approximately 0.70 lbs./in.².

Brief Description of the Drawings Other objects and advantages of the invention will be apparent from the detailed description and claims when read in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a side elevation view, depicting the process of pleating a plastic film material;

FIGURE 2 is a top plan view of the material after the pleats have been formed;

FIGURE 3 is a perspective view of the pleated material; and FIGURE 4 is a perspective view of the pleated material adapted for use as a window covering.

Best Mode for Carrying Out the Invention

In the description which follows, like parts are marked throughout the specification and the drawings, respectively. The drawings are not necessarily to scale and in some instances, proportions have been exaggerated in order to more clearly depict certain features of the invention.

Referring to FIGURE 1, a pleated window covering is manufactured by pleating a relatively flat sheet 10 of transparent plastic material. Sheet 10 is transported from a storage drum 12 onto a heating table 14, where it is pre-heated to a temperature in a range of approximately 76 'C - 106 'C, depending upon the thickness of material 10. A pair of blades 16 and 18 are disposed downstream of heating table 14 for engaging respective upper and lower surfaces 20 and 22 of sheet 10 to crease sheet 10 at selected locations thereon to define a pleated material 24. Top and bottom blades 16 and 18 are moved in a substantially reciprocating manner for sandwiching sheet 10 between respective facing surfaces 26 and 28 of blades 16 and 18. Sheet 10 should be pre-heated to a proper temperature, so that the respective surfaces 20 and 22 thereof are receptive to the gripping action of blades 16 and 18. Otherwise, sheet 10 will tend to slip along the respective surfaces 26 and 28 of blades 16 and 18, which can cause pleats of irregular size and shape to be formed.

After sheet 10 is pleated by the action of blades 16 and 18, pleated material 24 is transported into a stuffer box 30, where the temperature of pleated material 24 is maintained in a range of approximately 66 'C - 103'C by heaters 32 and 34, respectively positioned above and below pleated material 24, to hold the pleats in the desired shape. Pleated material 24 should be kept at an elevated temperature for a predetermined period of time (e.g., 6 - 15 minutes) in stuffer box 30 to ensure that the pleats retain their initial shape. An elongated bar 36 is placed in abutting relationship on a downstream side of the pleated material 24 for exerting pressure against the pleats in an upstream direction. This pressure tends to compress the pleats slightly within stuffer box 30 and cooperates with top and bottom heaters 32 and 34 to maintain the initial shape of the pleats . The upstream pressure exerted by bar 36 on the pleats will be in a range of approximately 0.33 lbs./in.² - 0.70 lbs./in.², depending on the thickness of the pleated material 24.

Referring also to FIGURE 2, pleated material 24 is moved slowly downstream, as indicated by the arrow, from stuffer box 30 onto a cooling table 38, where pleated material 24 is allowed to cool down to ambient temperature. Bar 36 continues to apply the aforementioned pressure to the pleated material 24 during a predetermined cool-down period, which is typically at least five minutes, to maintain the desired shape of the pleats 24.

The actual temperatures and pressures to which sheet 10 and pleated material 24 are subjected depends upon the thickness of sheet 10. The heating temperatures and the pressures applied to pleated material 24 will increase with increasing material thickness. For example, if sheet 10 has a thickness of approximately 2 mils, the sheet 10 will be preheated to a temperature of approximately 76"C and then will be maintained at a temperature of approximately 66"C - 73'C within stuffer box 30. Furthermore, the pressure applied to the pleats will be approximately 0.35 lbs./in.². If, however, the thickness of sheet 10 is on the order of 6 mils, the sheet 10 will be pre-heated to a temperature of approximately 106"C and will be maintained at a temperature of approximately 96"C - 103'C in stuffer box 30. The pressure applied to the pleats in this case will be approximately 0.70 lbs./in.². If sheet 10 has an intermediate thickness (e.g., approximately 4 mils), sheet 10 will be pre-heated to a temperature of approximately 91'C and will be maintained at a temperature of approximately 81^*C - 88"C within stuffer box 30. The pressure applied to the pleats would be approximately 0.42 lbs./in.². The proper combination of temperatures and pressures both in the pre-heating stage and in stuffer box 30 is required to form a pleated material 24 which is suitable for use as a window covering. Bar 36 moves downstream along with pleated material 24 to maintain a consistent pressure on the pleats both during the time that pleated material 24 is inside stuffer box 30 and after pleated material 24 has been moved onto cooling table 38.

Referring to FIGURE 3, pleated material 24 is defined by a plurality of substantially uniform, V- shaped pleats 40, having distinct crease lines 41. Each pleat 40 is comprised of a pair of substantially rectangular panels intersecting along the corresponding crease line 41 to define a V-shaped cross-section, taken transversely with respect to crease line 41. The width of each panel along a minor axis thereof and the length of each panel along a major axis thereof should be substantially uniform between panels. The desired results will not be achieved unless temperatures and pressures are properly regulated during the pleating process. For example, if the temperature of sheet 10 in the pre-heating stage is too high, sheet 10 may melt or bubble and the material may actually stick to blades 16 and 18 when blades 16 and 18 engage the incoming sheet 10. If, on the other hand, the temperature in the pre¬ heating stage is too low, irregularly shaped pleats 40 are likely to result and the pleats 40 may take on a half-moon shape, rather than a distinct V-shape. If the pleats 40 are not substantially V-shaped, they will not have the necessary elasticity to resist deformation forces associated with the collapsing and expansion of the window covering and will quickly lose their desired shape. Substantially the same problems will occur if the temperature in stuffer box 30 is either too high or too low because, even after pleats 40 are formed, they will not retain their initial shape if they are not maintained at a proper temperature within stuffer box 30 for the predetermined period of time (i.e., 6 - 15 minutes) . If the pressure is too high, a back pressure is exerted on sheet 10, which may cause sheet 10 to slip along respective surfaces 26 and 28 of blades 16 and 18. This slippage will cause variations in the size and shape of the pleats 40. Furthermore, excessive pressure will cause pleats 40 to buckle and slip along the surfaces of adjacent pleats 40, which will result in pleats of uneven size and shape. If, on the other hand, the applied pressure is insufficient, pleats 40 will not be pressed into the desired V-shape and will tend to take on a half-moon shape. If pleats 40 do not have a substantially uniform size and are not substantially V-shaped, as described above, they will not be suitable for use as a window covering, because they will not respond properly to the repeated collapsing and expansion associated with the normal operation of the window covering. Furthermore, as best seen in FIGURE 4, the size and shape of the pleats 40 must be substantially uniform in order to allow an operating cord 42 to be laced through aligned openings in the individual pleats 40. When the pleated material 24 is adapted for use as a window covering 44, pleated material 24 is typically disposed between top and bottom rails 46 and 48. The top rail 46 is usually stationary and bottom rail 48 moves up and down with pleated material 24, depending upon whether the window is to be covered or left uncovered. Bottom rail 48 adds stability to the window covering 44 to facilitate the free fall of pleated material 24 when pleated material 24 is released from top rail 46. Pleated material 24 can be cut to fit the size and shape of a particular window.

In the preferred embodiment, sheet 10 is preferably comprised of a transparent polyester film, which polarizes incoming light to filter out glare. The polyester film material also effectively absorbs and reflects both infrared energy and ultraviolet rays and substantially reduces the amount of heat flowing into a room through a window when the window is covered by the polyester film material. In effect, the polyester film material functions as a sunshade without interfering with the view through the window. The film material may include a reflective layer to provide one-way transparency, such that the window covering is transparent in only one direction for privacy.

One skilled in the art will appreciate that the actual sizes of the pleats 40 may vary, provided that they are substantially V-shaped and have a uniform size as described above. For example, the width of each pleat 40, as measured along a minor axis of one of the panels defining the corresponding pleat 40 will normally be from 0.75 inch to two inches, with one inch being a typical example. The length of each pleat 40, as measured along a major axis of the corresponding panel, will vary depending upon the width of the desired window covering. Various embodiments of the invention have now been described in detail. Since it is obvious that many changes in and additions to the above-described preferred embodiment may be made without departing from the nature, spirit and scope of the invention, the invention is not to be limited to said details, except as set forth in the appended claims.

Claims

1. A window covering comprised of a flexible material which substantially filters incoming sunlight to substantially reduce heat energy entering an indoor space through the window and which is sufficiently transparent to permit visibility through the window to the outside, said material being creased at selected locations thereon to define a plurality of pleats extending transversely with respect to a longitudinal axis of the window covering, said window covering being collapsible along said longitudinal axis by compressing the pleats together and being expandable along the longitudinal axis by expanding the pleats.

2. The window covering of Claim 1 wherein each of said pleats is defined by first and second substantially rectangular panels intersecting along a line defining a corresponding crease in the material, such that each pleat has a substantially V-shaped cross- section, each of the panels having substantially the same width along a minor axis thereof and substantially the same length along a major axis thereof.

3. The window covering of Claim 1 wherein said material is comprised of a transparent polyester film.

4. A window covering, comprising: a transparent plastic material which is creased at selected locations thereon to define a plurality of pleats extending transversely with respect to a longitudinal axis of the window covering, whereby said window covering is collapsible along said longitudinal axis by compressing the pleats together and is expandable along the longitudinal axis by expanding the pleats, said pleats being formed by the following steps: heating a relatively flat sheet of said material to a temperature within an approximate range of 76'C -106'C; creasing the sheet at selected intervals to define a pleated material; maintaining the pleated material in a temperature range of 66'C - 103'C for a first predetermined period of time; and applying pressure to the pleated material tending to compress the pleats in a range of approximately 0.33 lbs./in.² - 0.70 lbs./in.² for a second predetermined period of time.

5. The window covering of Claim 4 wherein said first predetermined period of time is approximately 6 - 15 minutes, said second predetermined period of time being substantially equal to said first predetermined period of time plus an additional period of time during which said pleated material is allowed to cool.

6. The window covering of Claim 5 wherein said additional period of time during which the pleated material is allowed to cool is at least five minutes.

7. The window covering of Claim 4 wherein each of said pleats is comprised of first and second substantially rectangular panels intersecting along a line defining a corresponding crease, such that each pleat has a substantially V-shaped cross-section.

8. The window covering of Claim 4 wherein said material is comprised of a transparent polyester film.

9. The window covering of Claim 4 wherein the thickness of the material is approximately .002 inch, said relatively flat sheet of said material being heated to a temperature of approximately 76'C, the pleated material being maintained in a temperature range of approximately 66'C - 73'C for said first predetermined period of time.

10. The window covering of Claim 9 wherein a pressure of approximately 0.35 lbs./in.² is applied to the pleated material for the second predetermined period of time.

11. The window covering of Claim 4 wherein said material has a thickness of approximately .004 inch, said relatively flat sheet of said material being heated to a temperature of approximately 91'C and being maintained in a temperature range of approximately 81'C

- 88^*C for said first predetermined period of time.

12. The window covering of Claim 11 wherein a pressure of approximately 0.42 lbs./in.² is applied to the pleated material for said second predetermined period of time.

13. The window covering of Claim 4 wherein the thickness of said material is approximately .006 inch, said relatively flat sheet of said material being heated to a temperature of approximately 106'C and being maintained in a temperature range of approximately 96'C

- 103^*C for said first predetermined period of time.

14. The window covering of Claim 13 wherein a pressure of approximately 0.70 lbs./in.² is applied to said pleated material for said second predetermined period of time.

15. A method of manufacturing a pleated window covering comprising the following steps: providing a relatively flat sheet of transparent plastic material and heating said sheet to a temperature within a range of approximately 76'C - 106'C; creasing the material at selected locations thereon to define a pleated material having a plurality of pleats extending transversely with respect to a longitudinal axis of the material; maintaining the pleated material in a temperature range of approximately 66'C - 103'C for a first predetermined period of time; and applying pressure tending to compress the pleats together in a range of approximately 0.33 lbs./in.² - 0.70 lbs./in.² for a second predetermined period of time.

16. The method of Claim 15 wherein the step of creasing the material includes folding the sheet of transparent plastic material at selected intervals, such that each pleat is comprised of first and second substantially rectangular panels intersecting along a corresponding crease to define a substantially V-shaped cross-section, each of said panels having substantially the same width along a minor axis thereof and substantially the same length along a major axis thereof to define substantially uniform pleats.

17. The method of Claim 14 wherein the said transparent plastic material is comprised of a relatively thin polyester film.

18. The window covering of Claim 15 wherein the thickness of the material is approximately .002 inch, said relatively flat sheet of said material being heated to a temperature of approximately 76 'C, the pleated material being maintained in a temperature range of approximately 66'C - 73'C for said first predetermined period of time.

19. The window covering of Claim 18 wherein a pressure of approximately 0.35 lbs./in.² is applied to the pleated material for the second predetermined period of time.

20. The window covering of Claim 15 wherein said material has a thickness of approximately .004 inch, said relatively flat sheet of said material being heated to a temperature of approximately 91^*C and being maintained in a temperature range of approximately 81'C

- 88^*C for said first predetermined period of time.

21. The window covering of Claim 20 wherein a pressure of approximately 0.42 lbs./in.² is applied to the pleated material for said second predetermined period of time.

22. The window covering of Claim 15 wherein the thickness of said material is approximately .006 inch, said relatively flat sheet of said material being heated to a temperature of approximately 106^*C and being maintained in a temperature range of approximately 96'C

- 103^*C for said first predetermined period of time.

23. The window covering of Claim 22 wherein a pressure of approximately 0.70 lbs./in.² is applied to said pleated material for said second predetermined period of time.

24. The method of Claim 15 wherein said first predetermined period of time is in a range from approximately 6 - 15 minutes.

25. The method of Claim 24 wherein said second predetermined period of time is substantially equal to said first predetermined period of time plus an additional period of time during which said pleated material is allowed to cool down.

26. The method of Claim 25 wherein said additional period of time is at least five minutes.

27. A window covering comprised of a relatively thin polyester film which substantially filters out incoming sunlight to substantially reduce heat energy entering an indoor space through the window and which is sufficiently transparent to permit visibility through the window to the outside, said film being creased at selected locations thereon to define a plurality of pleats, each of said pleats extending transversely with respect to a longitudinal axis of the window covering, such that the window covering is collapsible along said longitudinal axis by compressing the pleats together and is expandable along the longitudinal axis by expanding the pleats, each of said pleats being defined by first and second substantially rectangular panels intersecting along a corresponding crease line so that each of said pleats has a substantially V-shaped cross-section, each of said panels having a substantially uniform width along a minor axis thereof and a substantially uniform length along a major axis thereof so that each of said pleats has substantially the same size and shape.

28. A method of manufacturing a pleated window covering comprising the following steps: providing a relatively flat sheet of transparent plastic material and heating said sheet to a first predetermined temperature; creasing the heated sheet at selected locations thereon to define a.pleated material having a plurality of pleats extending transversely with respect to a longitudinal axis of the material; maintaining the pleated material at a second predetermined termperature, which is less than the first predetermined temperature, for a first predetermined period of time; and applying a predetermined amount of pressure tending to compress the pleats together for a second predetermined period of time.