WO2000009791A1

WO2000009791A1 - Sheet wiper

Info

Publication number: WO2000009791A1
Application number: PCT/US1999/018311
Authority: WO
Inventors: Evan Sundquist
Original assignee: Contec, Inc.
Priority date: 1998-08-13
Filing date: 1999-08-13
Publication date: 2000-02-24
Also published as: AU5557299A

Abstract

Six-sided sheet material wipers for use in cleansing surfaces in a controlled environment, such as in an industrial cleanroom, paint shop, or medical facility. The present invention also relates to an apparatus and method for packaging and dispensing the sheet wipers and a method of manufacturing sheet wipers involving cutting a plurality of hexagonal forms from sheet material, wherein the forms are oriented such that adjacent forms share common edges.

Description

SHEET WIPER

FIELD OF THE INVENTION

The present invention relates generally to sheet wipers of the type used in cleansing

surfaces in a controlled environment, such as in an industrial cleanroom, paint shop, or

medical facility. The present invention also relates to an apparatus and method for packaging

and dispensing sheet wipers, and further to a method of manufacturing sheet wipers.

Background of the Invention

Packaged wipers for cleansing surfaces in controlled environments have been

provided. A plurality of sheet wipers are typically placed into the interior cavity of a package

container. Depending upon the application, the individual wipers may be comprised of

knitted, woven, or nonwoven fabrics. Further, the packaged wipers may be provided dry or

presaturated with a liquid solvent. These liquid solvents may include volatile organic

compounds (VOC's) such as isopropyl alcohol or naptha, as well other materials such as

deionized or purified water. The solvent compositions may also include other ingredients

such as dipropylene glycol monomethylether. Typically, sheet wipers have been provided in

sizes of 81 in.² (9 in. x 9 in.) or in 144 in.² (12 in. x 12 in.).

For use in the most stringent cleanroom environments, wipers are generally made

from knitted fabrics of filament nylon or polyester yarn. These wipers have traditionally been

manufactured into square or rectangular configurations by cutting the fabric into the desired size wiper using a textile knife. This cutting process generates extraneous fibers, in part

because the knitted loops are cut. The cut fiber pieces remain on the fabric and represent a

potential for contamination. To remove this contaminant, the wipers are often laundered in a

cleanroom washing operation. After extraneous fibers are removed in this manner, the wipers

are packaged, in either dry or presaturated form, and are ready for use.

In part to reduce contaminant potential, sealed edge wipers were developed. Although

there are several methods of producing sealed edge wipers, the basic premise is the same.

Specifically, these products are made using converting operations that actually fuse the cut

loops into the edge of the wiper. This generally creates a cleaner cut and reduces fiber

contamination at the edges. While these sealed-edge wipers are generally cleaner than

conventional knife cut edges, they still tend to be more contaminated than the base fabric

alone. The sealed-edge products are also typically cleanroom laundered before they are

packaged.

In some environments, additional means are employed to further reduce the

contaminant potential of cut wipers. For example, in order to minimize contact with the cut

edges of a wiper, an operator may fold the wiper prior to application. One such protocol

requires that a square wiper be folded in half such that there are two short sides and two long

sides. Then the wiper is folded in half again, short side to short side, such that the folded

wiper has four equal-length sides. In this configuration, two of the wiper's sides are cut

edges, and the remaining two sides are folded surfaces. During application of the wiper to a

surface, the operator may orient the wiper such that surface contact with the cut edges is

minimized. Application of the folded wiper in this manner will generally reduce contaminant potential. Further, if the applied face of the wiper becomes soiled, the operator may unfold

the wiper and then refold it, so that an unused face of the wiper may be applied to the surface

in the manner described.

As described above, several techniques may be used to reduce the level of

contaminant potential posed by a wiper. Although these techniques may significantly reduce

the contaminant level of cut wipers, some environments may benefit from still lower

contaminant levels.

Summary of the Invention

The present invention recognizes and addresses the foregoing disadvantages, and

others, of prior art constructions and methods.

In one aspect, the present invention provides an improved sheet wiper. More

particularly, the present invention provides an improved fabric wiper with a lower level of

contaminants than prior art fabric wipers of comparable surface area. In addition, the present

invention maximizes the usable area of a wiper and thus minimizes wasted wiper area.

It has been determined that the contamination level of a fabric wiper is related to the

ratio of Wiper Area/Wiper Perimeter. For example, for square or rectangular cut wipers of

the prior art, larger size wipers (with a higher Area/Perimeter ratio) tend to be cleaner than

smaller size wipers (with a lower Area/Perimeter ratio). Therefore, a superior wiper design

would maximize the Wiper Area/Wiper Perimeter ratio for any desired area of wiper. For

customary wiper sizes, a circular wiper would present the cleanest configuration; however,

the circular configuration would generally be inefficient to manufacture. A preferred embodiment of the present invention provides a knitted fabric wiper with a hexagonal configuration of substantially uniform edge lengths. The improved hexagonal

wiper design increases the Area/Perimeter ratio over like-sized square and rectangular wipers

of the prior art. Accordingly, the present invention provides a wiper that is generally cleaner

than equivalent area wipers of the prior art. Further, the hexagonal design provides for an

efficient manufacturing process. In other preferred embodiments of the present invention, the

edge lengths may be varied for individual edges, or for pairs of opposing edges to achieve desired wiper profiles.

Effective wiping is best done when the pressure of the hand is directly above the fabric as it contacts the surface being wiped. Conversely, area in a fabric wiper which is not

directly under the hand is of little use. In comparison to prior art square and rectangular

wipers, the hexagonal wiper more closely approximates the shape of a user's hand with

fingers spread apart in a wiping application. As a result, there is less unused area present in a hexagonal wiper of the present invention. Thus, the improved hexagonal configuration of the

present invention is effective in maximizing the usable area of a wiper.

In another aspect, the present invention provides a package of improved knitted wiper

cloths for cleaning surfaces in a controlled environment. The package comprises a container

defining an interior cavity having a plurality of wiper cloths contained therein. The wiper cloths have a hexagonal configuration and may be in dry or presaturated form. In one embodiment, dry or presaturated hexagonal wipers having substantially equal edge lengths are packaged in a generally cylindrical container, such as a bucket. Inside the

container, the hexagonal wipers are stacked in a pile, preferably such that the edges of the wipers are approximately aligned. Preferably, the stack of aligned hexagonal wipers closely

approximates the shape and size of the cylindrical container interior. As a result, the

container can be densely packed with wipers, and very little space will be wasted.

In yet another aspect of the present invention, a methodology is provided for

fabricating knitted wiper cloths of the type for cleaning surfaces in a controlled environment.

Initially, a sheet comprising a knitted fabric web of filament synthetic yarn, such as nylon or

polyester yarn, is produced. This fabric web is then sent to a cutting operation for sonic, laser, hot air, or hot knife cutting. During this operation, the fabric web is cut into a honeycomb pattern of hexagonally shaped wipers. The hexagonally shaped wipers are then laundered to remove extraneous matter generated during the knitting, finishing or cutting

process. Typically, the wipers are laundered to the extent that a wiper in deionized water releases fewer than about 10 million particles of a size greater than about 0.5 μm per square

meter of apparent surface area of the faces. After the wipers are laundered, they are assembled in groups of a predetermined quantity. Each group of wipers is then packaged, and

saturated if desired.

Broadly, in one aspect, the present invention concerns a wiper comprised of sheet material such as knitted, woven and nonwoven fabrics having two opposing faces and six edges, wherein the six edges may be of equal or unequal lengths.

Broadly, in another aspect, the present invention concerns an apparatus for dispensing a plurality of six-sided sheet material wipers comprising a receptacle having a cross-sectional area which exceeds the area of the face of said wipers, which receptacle may comprise a bag or other container and may include a means for resealing, such as a removable cover or lid. Broadly, in another aspect, the present invention concerns a method of dispensing six-

sided wipers made of sheet material comprising stacking a plurality of said wipers in a

receptacle, which receptacle may include a means for resealing, such as a removable cover or

lid.

Broadly, in yet another one aspect, the present invention concerns a method of

manufacturing six-sided wipers from sheet material by cutting a plurality of hexagonal forms

oriented such that adjacent forms share common edges with cutting means that includes

sonic, laser, hot air, and hot knife.

Other objects, features, and aspects of the present invention are discussed below.

Brief Description of the Drawings

A full and enabling disclosure of the present invention, including the best mode

thereof, to one of ordinary skill in the art, is set forth more particularly in the remainder of the

specification, including reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a prior art rectangular wiper constructed in

accordance with the prior art;

Figure 2 is a plan view of a hexagonal fabric wiper constructed in accordance with the

present invention;

Figures 3 and 4 illustrate usage of the wipers shown in Figures 1 and 2, respectively;

Figures 5 A, 5B, and 5C illustrate a method of folding prior art wipers;

Figures 6A, 6B, and 6C illustrate a method of folding hexagonal wipers in accordance

with the present invention; Figure 7 is a cross-sectional view of a package, in one embodiment, of improved

wipers constructed in accordance with the present invention;

Figure 8 A is a cross-sectional view of a stack of hexagonal wipers contained in a

bucket; Figure 8B is a view of the stack of wipers shown in Figure 8 A as seen from above

with the lid removed; and

Figure 9 is a plan view of a fabric web diagrammatically illustrating the cutting of individual wipers therefrom in accordance with the present invention.

The drawings are provided for illustrative purposes only and should not be used to

unduly limit the scope of the invention.

Detailed Description of the Preferred Embodiments It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader

aspects of the present invention, which broader aspects are embodied in the exemplary

constructions.

Figure 1 illustrates a single wiper cloth 10 made according to the prior art. Wiper cloth 10 generally has a square or rectangular configuration. These configurations allow for an efficient manufacturing process and provide wiper cloths of generally acceptable contamination levels. However, some environments may benefit from wipers having an even

lower level of contaminants.

Figure 2 illustrates a single wiper cloth 20 made in accordance with one aspect of the present invention. Wiper cloth 20 has a hexagonal configuration with edges a-f all having substantially the same length. Of course, many other variations of the present invention are

obtained by varying the lengths of the edges. Like the prior art, the hexagonal configuration also allows for an efficient manufacturing process. In addition, the present invention provides a wiper cloth 20 that will often contain less contaminants than a comparably sized

square or rectangular wiper of the prior art.

It has been determined that the contamination level of a cut fabric wiper is related to

the ratio of Wiper Area/Wiper Perimeter. For example, a first wiper A of a specified area and perimeter is compared to a similarly constructed second wiper B having the same area but a smaller perimeter. Wiper B will generally be a cleaner wiper, because wiper B has a higher

Area/Perimeter ratio.

As an illustration, assume that prior art wiper 10 shown in Figure 1 has a wiper area

equal to that of wiper 20 shown in Figure 2. In comparison to the wiper 10, the hexagonal wiper 20 of the present invention has a shorter perimeter. Therefore, wiper 20 will generally contain a lower level of contaminants than wiper 10, assuming similar materials, processing

steps, and the like.

Figure 3 compares the shape of a user's hand 32 to the shape of a prior art wiper 10. As shown, the user's fingers 34 are spread over the wiper 10 as would be done in a wiping

application. Wiper area directly under the user's hand and fingers represents usable surface area. Conversely, area of the wiper 10 not located under the user's hand and fingers is

basically unused.

Figure 4 compares the shape of a user's hand 32 to a wiper 20 made in accordance

with the present invention. In comparison to wiper 10 of the prior art, the hexagonal configuration of the present invention more closely approximates the shape of the hand 32

with fingers 34 spread as in a wiping application. Accordingly, the present invention is

generally more effective in maximizing the usable area of a wiper. This means that the

hexagonally configured wiper 20 of the present invention may have a smaller overall area

than a wiper 10 of the prior art while providing the same amount of usable area.

For example, a hexagonal wiper having an area of no more than about 72 in.² may be

used where a 81 in.² square or rectangular wiper has been used in the past. Similarly, a

hexagonal wiper of no more than about 124 in.² compares to a 144 in.² square or rectangular

wiper of the prior art. In addition to reducing the perimeter length of the wiper and the

potential for contaminant represented thereby, a smaller area wiper will often yield a cost

savings in manufacturing. A smaller area wiper permits savings on material costs and allows

more wipers to be laundered at one time.

A smaller area wiper also allows the most efficient use of solvent applied with the

wiper, thus minimizing the amount of solvent used. Minimizing the amount of solvent used

is desirable from the standpoints of the cost of the solvents, the effectiveness of their

application to the surface, and minimizing the solvent concentration in the atmosphere of the

users' environment. The latter involves both the health of the users who are breathing this

atmosphere and the safety of the users in an environment where volatile liquids such as

solvents may pose a fire hazard. Additionally, it is well known that reducing NOC's released

to the atmosphere poses a positive impact on the environment.

Another advantage of the present invention is realized by those who follow a protocol

which requires the use of a folded wiper. In general, folding a square or rectangular wiper of the prior art requires the use of both hands. Conversely, folding a hexagonal wiper of the

present invention generally can be accomplished with one hand. As a result, a user can fold

the present wiper with one hand and manage a product or tool in the other hand.

The prior art folding process is illustrated in Figures 5A, 5B, and 5C, while the

present folding process is illustrated in Figures 6 A, 6B, and 6C. In Figure 5 A, the bottom half of wiper 10 is gripped by the user at two corner locations 51 and is folded over the top

half. In Figure 5B, the right half of wiper 10 is gripped at two locations 53 and is folded over

the left half. The resulting folded wiper 54 has two cut edges 56 and two folded sides 58. As

illustrated, folding a wiper 10 of the prior art generally requires two hands. In Figure 6 A, the bottom half of the present wiper 20 is gripped at a single location 61 and is folded over the top half. In Figure 6B, the right half of wiper 20 is gripped at a single

location 63 and is folded over the left half. As with the prior art wiper 54, the resulting folded wiper 64 of the present invention has two cut edges 66 and two folded sides 68.

However, as illustrated, folding a wiper 20 of the present invention generally requires only one hand. In order to achieve desired wiper profiles in a folded configuration, the edge

lengths of the present invention may be varied for individual edges, or for pairs of opposing edges, such as illustrated by edges a and d in Figure 2.

Figure 7 illustrates a package 70 of improved wipers constructed in accordance with

one aspect of the present invention. The package 70 comprises a bag 72, typically of polymeric, foil, or other sheet material, defining a container having a stack 74 of wiper cloths

located therein. Bag 72 is closable at its open end 76, using a bag tie, a tongue-and-groove mechanism such as that sold under the mark ZIP-LOCK, or other sealing device. In some exemplary embodiments, pack 70 may include a total of 150 dry or presaturated wiper cloths.

These packages may themselves be packaged for resale in multiples, such as multiples of two

(2).

Figures 8 A and 8B illustrate another package 80 of improved wipers constructed in

accordance with a further aspect of the present invention. The package 80 includes a

generally cylindrical bucket 82, typically made of a suitable plastic, having a stack 84 of

wiper cloths located therein. A removable lid 86 is located atop bucket 82 to close and seal

the opening. In some exemplary embodiments, the wipers within the bucket may be saturated

with a predetermined solvent. Additionally, the wipers may be stacked such that the edges 88

of the hexagonal wipers are at least approximately aligned. As such, the stack 84 of wipers

closely conforms to the shape of the inside of the bucket 82.

Figure 9 helps illustrate a methodology for fabricating wipers in accordance with

another aspect of the present invention. The preferred sheet material is a knitted polyester

fabric, but the scope of the invention may include other knitted synthetic fabrics, or even

sheet materials of woven or nonwoven fabrics depending on the requirements of a particular

usage. In the preferred method, a fabric web is cut into a plurality of hexagonal forms in a

honeycomb configuration, such that adjacent forms share common edges, thus minimizing

cutting operations and wastage of sheet material. In an example utilization of the preferred

method depicted in Figure 9, a fabric web 94 is cut into rows of hexagonal forms in a

honeycomb configuration such that each hexagonal cutout in a row shares a common side

with adjacent cutouts in the row. Also, each successive row of cutouts may be offset a

distance equal to one-half the width of the hexagonal form, such that each hexagonal form shares one common side with each of two adjacent forms in the succeeding row. A cutting

mechanism, such as a laser cutting device, can be utilized to cut the fabric web along the broken lines 96 of the hexagonal honeycomb. A plurality of individual hexagonally shaped wipers 20 can be produced in this manner.

In order to remove contaminants introduced during the cutting process, the wipers

may be taken to a cleanroom laundry and laundered in a washing application. After

extraneous fibers are removed in this manner, the wipers are grouped in a predetermined

quantity, and stacked if desired. The groups of wipers are then packaged, in either dry or presaturated form, and readied for sale.

Manufacturing the wipers in a hexagonal honeycomb configuration is an efficient production method. Generally, the hexagonally shaped wipers will use less sheet material,

while having the same usable area as those of the prior art. As a result, the production method of the present invention may provide cost savings to the manufacturer.

While prefened embodiments of the invention and preferred methods of practicing the same have been shown and described, modification and variations thereto may be practiced

by those of ordinary skill in the art without departing from the spirit and scope of the present

invention. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will

appreciate the foregoing description is by way of example only, and is not intended to be limitative of the invention.

Claims

1. A wiper comprised of sheet material having two opposing faces and six edges.

2. The wiper of Claim 1 wherein the six edges are of substantially equal length.

3. The wiper of Claim 1 wherein the sheet material is selected from the group consisting

of: knitted, woven, and nonwoven fabrics.

4. The wiper of Claim 1 wherein the sheet material is knitted fabric comprised of

filament synthetic yarn.

5. An apparatus for dispensing a plurality of six-sided sheet material wipers comprising

a receptacle having a cross-sectional area which exceeds the area of the face of said

wipers.

6. The apparatus of Claim 5 wherein the receptacle is cylindrical in form.

7. The apparatus of Claim 5 wherein the receptacle has a removable cover.

8. The apparatus of Claim 5 wherein the receptacle is a bag comprised of flexible sheet

material.

9 The apparatus of Claim 8 wherein the bag is closable.

10. The apparatus of Claim 9 wherein the bag is closable by incorporation of a tongue-

and-groove mechanism.

11. A method of dispensing six-sided wipers made of sheet material comprising:

stacking a plurality of said wipers in a receptacle.

12. The method of Claim 11 wherein the receptacle has a cross-sectional profile which

exceeds the surface profile of said wipers.

13. The method of Claim 11 wherein the receptacle is cylindrical in form.

14. The method of Claim 11 wherein the receptacle has a removable cover.

15. The method of Claim 11 wherein the receptacle is a bag comprised of flexible sheet

material.

16. The method of Claim 15 wherein the bag is closable.

17. The method of Claim 16 wherein the bag is closable by incorporation of a tongue-and-

groove mechanism.

18. A method of manufacturing six-sided wipers from sheet material comprising:

cutting a plurality of hexagonal forms from the sheet material, wherein the

forms are oriented such that adjacent forms share common edges.

19. The method of Claim 18 wherein the step of cutting a plurality of said hexagonal

forms is accomplished by means selected from the group consisting of: sonic, laser,

hot air, and hot knife mechanisms.

20. The method of Claim 18 further comprising the step of:

laundering the wipers.

21. The method of Claim 18 further comprising the step of:

assembling the wipers into groups of a predetermined quantity.

22. The method of Claim 18 further comprising the step of:

packaging the wipers.

23. The method of Claim 18 further comprising the step of:

laundering the wipers.

24. The method of Claim 18 further comprising the step of: saturating the wipers with a liquid solvent.

25. A method of manufacturing six-sided wipers from sheet material comprising:

cutting one or more rows of uniform hexagonal forms from the material, each

such row comprising a plurality of said hexagonal forms oriented such that

successive forms within each row share a common side.

26. The method of Claim 25 wherein the step of cutting one or more rows of uniform hexagonal forms further comprises:

cutting multiple rows of uniform hexagonal forms, each successive row offset

a distance equal to one-half the distance between parallel edges of said

hexagonal forms oriented such that each hexagonal form in a row shares one

common side with each of two adjacent forms in the succeeding row.