Feb. 11, 1964
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`‘
`-r. o. MATHUES
`'
`METHOD or MANUFACTURING SQUEEGEES
`Filed Jan. 16, 1961
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`3,12l.,l33
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`INVENTOR.
`7'//0/1//.43 0. MATHUES
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`mass SE07‘/0/V_ or BLADE \
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`Costco Exhibit 1017, p. 1
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`Costco Exhibit 1017, p. 1
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`

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`1
`3,121,133
`PETHQD (3F MANUFAEJTURKNG SQUjEGEES
`Thomas (3. Mathues, Dayton, @hio, assignor to General
`Motors Corporation, -'etroit, Mich, a corporation of
`Delaware
`Filed den. 15, @153, Ser. No. 83,667
`5
`(Q3. 264-—24l)
`This invention relates to squeegees and is particularly
`concerned with a method for making squeegees for use
`with windshield wipers.
`The main object of the invention is to provide a
`method for making a squeegee which includes a plu
`rality of strata of different hardness elastomers whereby
`the completed squeegee includes an integral retention
`portion together with a ?exible wiping portion.
`‘In carrying out the above object it is a further ob
`ject of the invention to provide a method for making a
`windshield wiper squeegee wherein a plurality of strips
`of uncured elastomeric material are provided each being
`capable upon curing of resulting in a different hardness
`elastomer whereby, when said strips are integrated dur
`ing the molding and curing steps, an integral laminated
`lade or squeegee is formed having a relatively hard
`retention portion and a relatively resilient wiping por
`tion.
`A still further obiect of the invention is to provide a
`rethod for making an integral squeegee of elastomeric
`material wherein the relative hardness of the material
`from the retention portion to the wiping lip thereof is
`progressively softer and wherein the strata making up
`the several portions of the squeegee are merged one into
`the other without de?nite lines of demarkation or iden
`'ty.
`Further objects and advantages of the present inven
`tion will be apparent from the following description, ref
`erence being had to the accompanying drawings wherein
`pres ‘erred embodiments of the present invention are clear
`ly shown.
`In the drawings:
`PEG. 1 is a view in perspective showing a portion of
`one type of windshield wiper squeegee.
`FIG. 2 depicts a laid-up section of elastomeric ma
`terial about to be positioned in the lower part of a com
`pression mold.
`3 is a chart showing the relative hardness of the
`elastomeric material in a ?nished squeegee through the
`cross section of the blade wherein the solid line is di
`rected to a blade having three strata of material whereas
`the dotted line is directed to a blade having only two
`strata of material.
`in copendins7 application Serial No. 83,005, ?led lanu
`ary 16, 1961, now Patent No. 3,116,506, in the names
`of Clyde A. Browne and Elmer E. Reese, assigned to the
`assiwnee of the present invention and ?led concurrently
`herewith, a windshield wiper blade or squeegee is de
`scribed whieh includes an integral elastomeric portion
`having two or more strata of different hardness elas
`tomers making up the structure. in this blade the re
`tention portion of the squeegee is relatively hard when
`compared to the wiping or lip portion thereof. The
`present invention is directed speci?cally to a method for
`making blades of this general character since it is quite
`apparent that numerous problems will occur in obtaining
`the desired variations in hardness over the cross section
`of an elastomeric squeegee.
`Referring to the drawings, PEG. 1 indicates a squeegee
`at
`having a retention portion 22 which includes an
`upper ?ange
`and a lower flange 26. A neck 28
`connects the retention portion 22 with the blade or lip
`portion 3i) which tapers outwardly to a very thin and
`?exible wiping lip.
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`file
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`3,l2l,l33
`‘Patented Feb. 11, 1954
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`2
`In accordance with the aforementioned Browne and
`Reese invention, it is desired to have the retention por
`tion 22 in whole or in part, formed from a harder elas
`tomeric material than is used in the blade portion 30
`thereof. Furthermore, it is sometimes desirable to have
`varying degrees of hardness in varying strata running
`longitudinally of the squeegee. For this reason, and ‘for
`purposes of illustration only, the parts 24, 26 and 30
`will be formed from stratum of dilferent hardness al
`though it is to be understood that the entire retention
`portion 22 may be made from one hardness material
`while the blade portion may be made of another.
`It is well known in the art, when elastomeric materials,
`such as rubber-like materials, are compression molded
`that it is necessary to load the mold with a predeter
`mined quantity of moldable material. This is generally
`determined by weight so that very little excess is pres
`out. This slight excess generally takes the form of
`dash, or sprues which is removed from the ?nished prod
`uct. It is necessary that a slight excess be used in order
`to insure complete ?lling of the mold whereby a faith
`ful representation of the part may be molded.
`In the present instance it is highly desirable to mold
`two blades simultaneously and to later cut the blades
`apart at the thinnest portion thereof whereby a precision
`wiper edge is obtained. The various rubber stocks used
`in the several portions of the blade are compounded in
`such a manner as to yield the desired hardness in the
`various strata of the cured material. These speci?c
`stocks are next extruded in blank form wherein the blank
`approximates in shape the speci?c contour desired in the
`mold. Desired lenvths of the blanks are cut so that the
`proper weight of material is provided. The cut lengths
`of blanks being uncured are somewhat tacky and may
`be adhered together by slight pressure to form a laid
`up slug or charge which may be placed in one section
`of the mold. Such an assembly is shown in FlG. 2,
`‘wherein a slug, or charge, 4%} of rubber-like material is
`shown as it is being placed in a mold section 42. The
`section 44 of the charge 40 will ultimately become the
`molded portion 24 or" the squeegee 2%. The part 46
`will ultimately become the part 26 of the retaining por
`tion 22 whereas the parts 43 and 5d will ultimately be
`come the ?exible wiping lip 3b‘ of the blade as shown at
`2%}. The opposite side of the charge has identical parts
`to those already described.
`Each of these strips 44, 436 and '43 may be extruded
`from different compounds which are capable of curing
`under identical time conditions whereby when the charge
`443 is placed in the mold ‘412 and the upper half, not
`shown, is forced thereon and so that the charge 4d will be
`compressed to completely ?ll the mold and present a faith
`ful reproduction thereof while the various lamina or sec~
`tions become homogeneous strata of the cured unitary
`blade.
`FIG. 3 indicates in solid lines a curve indicating the
`relative hardness of various portions of the squeegee taken
`through the cross section thereof. In this instance, and
`for illustration purposes only, the top of the retention
`portion ‘as indicated at 24 in FIG. 1 will have a hardness
`of about 95 (Shore A). The lower portion of the reten
`tion member as indicated at 215 in FIG. 1 will have a hard
`ness in the order of 80 (Shore A). The wiping lip or
`?exible portion 39 will have a hardness of about 60 (Shore
`A). In this connection it is apparent that the relative
`hardness of the various stratum of the blade may vary con
`siderably in accordance with the design of the squeegee
`which, in turn, will vary 'm accordance with the design or
`contour of the Windshield with which it is to be used. In
`other words, a heavily contoured windshield generally re
`quires greater hardness in the retention portion of the
`
`Costco Exhibit 1017, p. 2
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`

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`3,121,133
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`21
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`squeegee than a relatively ?at Windshield. These factors
`are best determined by trial.
`Again referring to PEG. 3, if only two hardness elas
`tomers are used in the squeegee 2d the cross section will
`follow the dotted line curve of FIG. 3 wherein the reten
`tion portion Will again be in the order of 95 (Shore A)
`hardness while the blade portion will drop down to 50
`to 60 (Shore A) hardness. In this connection, since the
`blade portion 30 is connected to the retention portion
`22 by means of the neck 23 it is apparent that there will
`be a section Within the neck 28 of varying hardness Where
`the two stratum merge together. This merging, which
`will occur whenever stratum of different formulations are
`adjacent one another, is caused by interditl’usion of the
`components of the recipe togeti er with a mechanical in
`termingling of the materials due to the compression mold
`ing step.
`in place of extruding the various sections ‘of the laid
`up charge it is possible to sheet the several materials on
`a mill wherein the sheets are milled to the desired thickness
`and then, by means of a blade, are cut into strips of the
`desired Widths. The width of these strips is predeter
`mined ?oy trial so that when the various strips may be
`laid up into a charge and compression molded that suf
`?cient material will be present to completely ?ll the mold
`and faithfully reproduce the contours thereof on the mold
`ed object.
`Speci?c formulations which may be used it ill vary Wide
`‘1y as is well known in the art. A great majority of wind
`shield Wiper vSqueegees used today are made from high
`grade crepe rubber although it is within the scope of
`this invention to utilize such elastomers as butadiene
`styrene copolymers, butadiene-acrylonitrile copolymers,
`butadiene-acrylonitrile-phenolics, polychloroprene, butyl
`rubber, etc.
`Speci?c examples of recipes which may be cured under
`similar time conditions and which will uti-mately result
`in rubbers having speci?c hardness as indicated are as
`follows:
`
`Example I.—Sh0re A 60 Hardness
`Pts. by wt.
`Natural rubber (pale crepe) ________________ __ 100.0
`Mercaptobenzothiazole disul?de _____________ __
`1.0
`Tetramethylthiuram disul?de _______________ __ 0.15
`
`Sulfur ___________________________________ __ 2.75
`Sym. dibeta-naphthyl-paraphenylene ‘diamine ____
`1.0
`Zinc oxide _______________________________ __ 10.0
`Stearic acid ______________________________ __ 0.75
`U.O.P. 288 (N,N’di 2 octyl-p-phenylene diamine __
`1.0
`Carbon black (medium thermal) ____________ __ 50.0
`Oil _____________________________________ __
`3.0
`Cure time—10 min. @ 300° F.
`Example 1l.—Shore A 80 Hardness
`Pts. by wt.
`Same as Example I except for carbon black Which
`should be E.P.C. (easy processing) _________ __ 75.0
`Same cure time and temperature.
`Example 1H.—Slz0re A 95 Hardness
`Pts. by wt.
`Rubber:
`Natural rubber (pale crepe) ______ __ 80 pts.
`Butadiene styrene copolymer _____ __l 2,, ,
`High styrene, “Pliolite” S—6 ______ __{ ‘’ 1“
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`100.0
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`High abrasion carbon black ________________ __ 80.0
`Zinc oxide _______________________________ __ 10.0
`Stearic acid ______________________________ __ 0.75
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`Sulfur ___________________________________ __
`Light process oil _________________________ __
`Sym. dibeta-naphthyl-para-phenylene diamine ___
`N cyclo hexyl 2 benzothiazole sulphenamide ____
`Cure time-10 min. @ 300° F.
`In the above recipes various other materials may be sub
`stituted in the compound as is Well known in the art.
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`3.0
`1.0
`1.0
`0.5
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`.rardness thereof will vary
`Further, it is apparent that
`in most instances as the qt .-ity of carbon black and vul
`canizing agent(s) vary, the more carbon black, the harder
`the material, etc.
`It is also apparent that in place of using rubber-like
`compounds which will cure under identical time condi
`tions that it is possible and often desirable to utilize com
`pounds which do not cure under identical conditions.
`in this connection it is highly desirable in some in
`stances to utilize a rubber-like material in the harder por
`tion of the squeegee which requires a longer cure than
`the material used in the softer or ‘blade section thereof.
`This may be explained as follows:
`In certain instances when compression molding opera
`tions are being carried out there is a tendency for the
`materials to intermingle excessively where complicated
`cross sections are being made and in these instances, there
`fore, it is highly desirable that the harder material or re
`tention portion be partially cured before it is ?nally mold;
`ed with the blade portion. In this case the partial cure
`should not be so long as to destroy the mobility of the
`material whereby after the partially cured part is molded
`in the mold, together with ‘an uncured portion of the
`blade, the cure is continued. In this case, the cure time
`for the uncured material will be equal to the remainder
`of the curing period for the partially cured part. In this
`manner, the two parts may be molded together and due
`to the degree of mobility remaining in the partially cured
`part, a homogeneous blade will be obtained including
`two or more stratum of different hardness rubbers, as the
`case may be. It is apparent in this instance that co-min
`gling of the materials at their interface is lesesned to a
`degree although, again, there will be an area at the in
`terface Where a degree of co-min-gling is present to form
`a homogeneous blade. Longer cure times may be ob
`tained by changing the quantity of accelerator and/ or our
`ing agent used, such variations being well lmown in the art. .
`it is also understood that where extrusion techniques
`are used to form a slug or charge of material that the ex
`trusion may be formed to substantially the exact shape
`of the part to be molded but in each instance it is desir
`able that the overall cross section of the part be slightly
`larger, in the order of ‘some 1% to 2% by weight of the
`?nished part, so that pressure Will he obtained during the
`molding operation to completely ?ll the mold and force
`the several lamina into intimate relation to one another
`at their interfaces ‘for facilitating the integration of the
`strata?ed structure.
`In addition to the formulations set forth in Examples I,
`II and III, attention is directed to the Vanderbilt Rubber
`Handbook published in 1948 by the R. T. Vanderbilt
`Company, pages 194 and 195 thereof, Where various rub
`ber compounds are set forth having different degrees of
`hardness together with the ‘conditions under which the
`cures are carried out. Also, on pages 200 and 201, buta
`diene-styrene formulations are set forth for varying hard
`ness rubbers whereas on pages 204 and 205 blends of
`natural rubber and butadienestyrene material having
`varying degrees of hardness are set forth.
`While the embodiments of the present invention as
`herein disclosed, constitute preferred forms, it is to be
`understood that other forms might be adopted.
`What is claimed is as follows:
`1. In a method for making a vehicle Windshield Wiper
`squeegee comprising a ?exible, unitary, elongate body of
`solid elastomeric material having a longitudinally extend
`ing Wiping portion and a longitudinally extending reten
`tion portion and having longitudinally extending strata of
`different hardness, said wiping portion being formed at
`least in part by a soft stratum and said retention portion
`being formed at least in part by a hard stratum, the steps
`comprising; compounding a relatively hard curable elas
`tomer, compounding a second and relatively softer curable
`elastomer, forming predetermined quantities of each of
`said compounded elastomers into elongate bodies of the
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`30
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`45
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`50
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`55
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`60
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`65
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`70
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`75
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`Costco Exhibit 1017, p. 3
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`

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`5
`approximate cross sectional shapes ultimately desired in
`the retention and wiping portions respectively and each
`including the desired weight of the speci?c compound re
`quired, positioning said formed elongate bodies in as
`sembled juxtaposed linear relation within a mold, com
`pression molding and curing the assembly of said bodies
`Within said mold for causing a merging of the compounds
`at their longitudinal interface therebetween to form an
`integral strata?ed linear Windshield wiper squeegee hav
`ing a retention portion comprising a relatively hard stra
`tum and wiping portion comprising .a relatively softer and
`more ?exible stratum joined longitudinally by a stratum
`of intermediate hardness, each of said stratum extending
`substantially throughout the length of the squeegee and
`?nally cutting the wiping portion longitudinally thereof
`for forming a precision cut edge thereon.
`2. In a method vfor making a vehicle windshield Wiper
`squeegee comprising a flexible, unitary, elongate body of
`solid elastomeric material having a longitudinally extend
`ing (Wiping portion and a longitudinally extending reten
`tion portion and having longitudinally extending strata of
`di?erent hardness, said wiping portion being formed at
`least in part by a soft stratum and said retention portion
`lbeing formed at least in part by a hard stratum, the steps
`comprising; compounding a relatively hard curable elas
`tomer, compounding a second and relatively softer curable
`elastomer, extruding elongate strips of said two com
`pounded elastomers in the approximate ‘cross sectional
`shapes ultimately desired in the retention and wiping
`portions respectively positioning said strips in assembled
`
`6
`in abutting juxtaposed linear relation within a mold and
`?nally compression molding and curing said juxtaposed
`strips within said mold for causing a merging of the
`compounds at their ‘interface to form an integral strata
`?ed linear Windshield wiper squeegee having a retention
`portion comprising a relatively hard stratum and wiping
`portion comprising ‘a relatively softer and more ?exible
`stratum joined longitudinally by a stratum of intermediate
`hardness, each of said stratum extending substantially
`throughout the length of the squeegee.
`3. The method claimed in claim 1 wherein the rela
`tively lharder curable compound is partially cured prior to
`its assembly ‘and ?nal cure with the softer curable elas—
`tomer.
`4. The method claimed in claim 2 wherein said un
`cured strips are mechanically adhered in juxtaposition
`prior to placement within the mold.
`5. The method claimed in claim 52 wherein said un
`cured strips are assembled in juxtaposed relation within
`the mold.
`
`References Cited in the ?le of this patent
`UNITED STATES PATENTS
`Campbell ____________ __ Nov. 20, 1923
`Weida ______________ __ Nov. 27, 1923
`Willshaw _____________ __ May 26, 1925
`Teed ________________ .._. Aug. 14, 1928
`Maynard ____________ _._r_.. Mar. 3, 1942
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`1,474,510
`‘1,475,463
`1,539,618
`1,680,823
`2,275,081
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`3,121,133
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`Costco Exhibit 1017, p. 4