July 5, 1965
`
`w. D. APPEL
`WINDSHIELD WIPER BLADE ASSEMBLY
`
`3,192,551
`
`Filed Aug. 31, 1964
`
`3 Sheets-Sheet 1
`
`INVENTOR
`WALTER D. APPEL
`
`87.19%; 14
`
`A 7' TORNEYS
`
`Costco Exhibit 1004, p. 1
`
`

`

`July 6, 1965
`
`w. D. APPEL
`WINDSHIELD WIPER BLADE ASSEMBLY
`
`3,192,551
`
`Filed Aug. :51, 1964
`
`'s Sheets-Sheet 2
`
`“iii-5E
`
`INVENTOR.
`W191 7'15? 0. ?PPA-“L
`
`kéw/my
`
`Costco Exhibit 1004, p. 2
`
`

`

`July 6, 1955
`
`‘w. D. APPEL
`WINDSHIELD WIPER BLADE ASSEMBLY
`
`3,192,551
`
`Filed Aug. 31, 1964
`
`3 Sheets-Sheet 3
`
`12_
`"1
`
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`
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`
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`
`INVENTOR
`WALTER D. APPEL
`
`A T TOR/VEVS
`
`Costco Exhibit 1004, p. 3
`
`

`

`United States Patent 0
`ice
`
`3,l§2,55l
`Patented July 6, 1965
`
`I
`
`3,192,551
`WINDSHIELD WEER BLADE ASSEMBLY
`‘Walter I). Appel, 4350 Commerce Road,
`?re-hard Lake, Mich.
`Filed Aug. 31, 1964, Ser. No. 3%,386
`9 Claims. (Ql. 15-25056)
`
`10
`
`15
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`The present application is a continuation-in-part of my
`co-pending application Serial No. 196,254, ?led May 21,
`1962, now abandoned.
`This invention relates to improvements in windshield
`wiper blade assemblies and more particularly to a simpli
`?ed spring wiper blade backbone construction ?exibly
`adaptable to e?icient wiping of variable curvatures as well
`as relatively ?at portions of vehicle Windshields.
`The present construction presupposes a wiper actuating
`arm adapted to provide a pre-determined total resilient
`pressure-loading of the wiper blade against the wind
`shield’ surface appropriate to the length of the blade and
`curvature variations in the windshield, e.g. in the order
`of one ounce per inch of blade length, as well as an ap
`propriate source of power for actuating the wiper under
`normal conditions. A single spring element is provided
`as a backbone to which is mounted a conventional ?exible
`rubber wiping blade which together operate to distribute
`a centrally applied actuating arm pressure load relatively
`uniformly along the length of the blade throughout vari
`ations in windshield contour traversed by the wiper.
`Preferably the resilient backbone member is adapted for
`actuating arm attachment at or near the center and is
`constructed of spring metal or other resilient material
`bowed with a free contour surface having a radius of
`curvature less than that of the windshield traversed by
`the wiper assembly, together with a varying width and/ or
`thickness of such resilient member from a maximum near
`the central arm attachment point to a minimum at the
`ends, the width, thickness and degree of free curvature be
`ing proportioned with the modulus of elasticity, total
`pressure load and length of blade to provide substantially
`uniform pressure along the length of contact between
`the ?exible rubber wiping blade and the windshield.
`In order to meet extreme conditions of variations in
`windshield curvature it may be desirable in some instances
`to taper the ends of the spring backbone element in thick
`ness as well as in width in order to accommodate a cor
`respondingly smaller radius of curvature while retaining
`appropriate width for resisting lateral drag loads without
`undue distortion.
`These and other objects of the invention may best be
`understood by reference to the drawings illustrating a
`preferred embodiment wherein:
`FIG. la is an isometric view of a spring element having
`uniform width and thickness and a free form parabolic
`curvature adapted to develop a uniform pressure when
`pressed against a ?at surface;
`FIG. 1b is a similar view of such element in a par
`tially ?attened condition;
`FIG. 1c is a similar view of such element in a fully
`?attened condition;
`FIG. 2a is a similar view of an alternate spring ele
`ment having a uniform thickness and variable width to
`gether with a free form circular arc curvature;
`FIGS. 2b and 2c are similar views of such alternate
`element showing progressive de?ection against a flat sur
`face;
`FIG. 3a is a similar view of a second alternate con
`struction showing a spring element with uniform width,
`tapered thickness and a free form circular arc curvature;
`FIGS. 3b and 3c are similar views showing the progres
`sive wrapping action of such second- alternate spring ele
`ment when pressed against a ?at surface;
`FIG. 4' is a'plan view of a preferred embodiment of
`
`2
`a windshield wiper blade assembly employing a spring
`backbone element similar to that illustrated in FIGS.
`2a-2c;
`FIG. 5 is a side elevation of such preferred embodi
`ment;
`FIG. 6 is a sectional view taken along the line 6-6
`of FIG. 4;
`'
`FIG. 7 is a sectional view similar to FIG. 6 showing
`a modi?ed construction for attachment of a rubber wiping
`blade;
`FIG. 8 is a sectional view similar to FIG. 6 showing a
`modi?ed construction for attachment of a rubber wiping
`blade to a spring backbone of the type illustrated in FIGS.
`3a-3c;
`,
`FIG. 9 is a side elevation of a modified embodiment
`of a windshield wiper blade assembly employing a spring
`‘backbone element as shown in FIGS. 10, 11, and 12;
`FIGS. 10, 11 and 12 are sectional views taken along
`corresponding lines in FIG. 9; and
`FIGS. 13, 14 and 15 are views similar to FIGS. 10, ll
`and 12 showing another modi?cation of the spring back
`bone.
`The present approach to providing substantial uniform
`pressure. with a single spring backbone construction may
`best be understood by ?rst considering the conditions
`which would produce uniform pressure on a ?at wind
`shield surface. With reference to FIGS; la-lc uniform
`pressure loading along the length of a spring 29 having
`uniform width 21 and uniform thickness 22 could be
`accomplished ‘by providing an appropriate ‘free state
`parabolic form having its principal axis normal to the
`center of the spring such that if moved from a spaced
`position normally toward a ?at windshield surface 25,
`the ends 26 would make initial contact with progressive
`“wrapping” of the spring against the windshield from the.
`ends toward the center as shown in FIGS. 1b and 10 as
`increasing pressure is applied at the center. The para
`bolic free form required for completely uniform distribu
`tion of pressure for a given total central loading P will
`depend upon the length, thickness, width and modulus of
`elasticity of the material used. For a given modulus of
`elasticity, relatively‘thinner or narrower sections will re
`quire relatively greater de?ection and deeper free para
`bolic form to .produce a given total uniform pressure
`loading.
`As illustrated in FIGS. 2a-2c, by tapering the spring
`width 27 from a maximum at the center to a minimum
`at the ends and making such taper in the form of parabolic
`arcs having their principal axes normal to the ends 28 of
`the spring (see also FIG. 4), the free form longitudinal
`section for producing uniform load distribution can be
`converted from a parabolic free form having only slight
`free form curvature at the ends (FIG. 1) to a circular
`arc of uniform free form curvature which again will
`“wrap” at a uniform rate from the ends 28 to the center
`29 with increasing center pressure loading as shown in
`FIGS. 2b and 2c, and when fully ?attened, the bending
`stress as well as the unit pressure loading of the spring will
`be uniform throughout, as distinguished from the pre
`viously discussed uniform width parabolic form of spring
`element where the bending stress is non-uniform and
`maximum at the center.
`With reference to FIGS. 3a-3c, a similar result can
`be achieved by providing a uniform width 31‘ of spring 32
`which has a uniformly tapered thickness 33 from a maxi
`mum at the center 34 to a minimum at each end 35 in
`which case a circular are free form longitudinal section
`will again result in uniformly progressive “wrapping”
`from the ends to the center with uniform pressure contact
`loading along the length of the spring from a centrally ap
`plied load P as illustrated in FIGS. 3b and 3c. The effect
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`50
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`60
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`70
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`Costco Exhibit 1004, p. 4
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`

`

`4
`what less curvature, adapted to provide uniform contact
`pressure along the length of contact with a ?at windshield
`43 when fully depressed by the actuating arm (not! shown).
`The reduced curvature at the ends departing from a true
`circular arc may be required where, as in this embodi
`ment, the parabolic sides terminate at each end with a
`?nite width rather than a point. The theoretically proper
`curvature at such ends would be intermediate the para
`bolic curvature shown in FIG. 1 incident to a spring
`cross section of uniform width and thickness and the cir
`cular curvature shown in FIG. 2 incident to parabolic
`sides meeting at a point at either end; however, as a prac~
`tical compromise the provision of a circular curvature
`terminating somewhat short of straight end portions has
`been found satisfactory due to the ability of the rubber
`wiper blade to compensate for a limited degree of non
`uniform spring load.
`FIGURE 7 shows a modi?cation in detailed construc~
`tion of the rubber wiper blade and attaching means in
`which a spring backbone element 45 similar to that of
`FIGS. 4—6 has a modi?ed rubber blade 46 attached by
`bonding at 47. The modi?cation of FIG. 8 shows a simi
`lar modi?ed rubber blade 48 similarly attached by bond
`ing at 4-9 to a spring backbone 5d of the tapered thickness
`type shown in FIGS. 3a-3c.
`_
`From the above description of a preferred embodiment
`and certain modi?cations it will be understood that nu
`merous other modi?cations might be resorted to without
`departing from the scope of this invention as de?ned in
`the following claims.
`"
`' I claim:
`1. A windshield wiper blade assembly including a
`wiper element, a flexible spring backbone element con
`nected to the wiper element, attaching means adjacent the
`center of said backbone element, said backbone element
`having coordinated length, section width, thickness, modu
`lus of elasticity and free form longitudinal curvature ex
`ceeding any subtended windshield curvature and including
`progressive dimensional variations providing a parabolic
`effect
`
`10
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`40
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`45
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`"
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`3,192,551
`
`3
`of taper may be simulated by using spring stock of uni~
`form thickness having a reinforcing rib as shown in FIGS.
`9-12 or ribs as shown in FIGS. 13-15 of progressively in
`creasing depth from ends to center formed in the center of
`the spring; or ?anges (not shown) of tapering depth may
`be formed at the edges of the spring to provide progres
`sively increasing resistance to bending from the ends to
`the center.
`'
`Thus a parabolic effect in spring rate leading to pro
`gressive “wrapping” from ends to center and uniformity
`of pressure contact can be achieved through the provision
`of ( 1) a parabolic form of free curvature in a spring of
`uniform section; (2) a parabolic form of width in a spring
`of uniform thickness and uniform curvature; or (3) a
`uniformly tapered thickness in a. spring of uniform width
`and uniform curvature. Obviously, it is also possible to
`combine in a number of different ways these various con
`structional approaches incorporating progressive dimen
`sional variations in free form curvature, width and/or
`thickness along its length to provide a single spring back
`bone element having uniform pressure loading'character
`istics when pressed against a ?at windshield‘ Whichever
`construction is used, it is the combination of the ?exible
`rubber wiping blade with the spring backbone element
`which determines the ?nal pressure characteristic‘between
`the Wiping blade and the windshield surface. For this
`reason the shape and section of the ?exible rubber wiping
`blade must also be taken into account with the spring
`backbone element in determining the proper design pro
`portions.
`30
`With whatever speci?c constructional form is employed.
`it may be adapted to also provide substantially uniform
`pressure loading on any given curved windshield surface
`by adding to the free form curvature which produces
`uniform pressure loading on a ?at surface the additional
`curvature of the curved windshield surface. In this man
`ner a single spring may be adapted to provide uniform
`pressure on any average or extreme curvature surface or
`intermediate curvature portion of a variable windshield
`surface. In this connection where a wiper is required
`to operate over substantially variable curvatures, a fully
`uniform pressure can be provided for only one speci?c
`curvature with a ?xed, pre-determined total pressure load
`ing provided by the wiper actuating arm but variations
`in pressure may be minimized in several ways which will
`permit the present simpli?ed spring construction to per
`form a completely satisfactory Wiping job. One is to
`adopt a uniform pressure curve intermediate the extremi
`ties of maximum and minimum curvature contours
`traversed by the wiper; another is to employ a spring
`material having a high modulus of elasticity and high
`fatigue strength combined with a relatively light section
`and high degree of free curvature for the desired total
`loading so that the “rate” of the spring will be minimal
`and the variations in curvature of the windshield a mini
`mal fraction of the total de?ection. These provisions,
`together with the resiliency of the rubber wiping blade
`per se in accommodating itself to some variation in pres
`sure loading, have been found to permit a completely
`satisfactory and effective wiper to be constructed with the
`present single spring backbone element, a preferred em
`bodiment of which will now be described.
`With reference to FIGS. 4-6 a spring backbone ele
`ment 36 of the type illustrated in FIGS. 2a-2c may be
`adapted to carry a conventional rubber. wiping blade 37
`by providing a slot 38 extending almost throughout the
`length and terminating just short of the end 39 for ac
`commodating a ?anged rib 40 of the rubber blade pro
`jecting therethrough. The sides of the backbone may be
`sprung apart to facilitate attachment of the rubber blade
`before actuating arm attachment clip 41 is secured thereto
`by rivets 42 providing a permanent assembly for retaining
`the rubber blade 37 in position. As shown in FIG. 5 the
`backbone 36a and rubber blade 37a have a free form
`circular arc curvature modi?ed at ‘the ends with some
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`3,192,551
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`10
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`5
`6
`spring backbone element having a varying effective thick
`cluding progressive dimensional variations providing a
`ness providing an increasing spring rate.
`parabolic effect in spring rate normal to the windshield
`4. A windshield wiper blade assembly including a
`surface adapted in engagement in a normal direction
`wiper element, a ?exible spring backbone element con
`against a predetermined windshield surface to make pro
`nected to the Wiper element, attaching means adjacent the
`gressive “wrapping” pressure contact from ends to center
`center of said backbone element, said backbone element
`as a predetermined normal pressure loading is gradually
`having coordinated length, section width, thickness, mod
`applied through said attaching means, said spring back
`ulus of elasticity and free form longitudinal curvature
`bone element having a varying thickness of section de?ned
`by substantially uniform linear taper providing a spring
`exceeding any subtended windshield curvature and includ
`ing progressive dimensional variations providing a para
`rate increasing approximately as the square of the distance
`inwardly toward’the center.
`bolic effect in spring rate normal to the windshield sur
`face adapted in engagement in a normal direction against
`8. A windshield Wiper blade assembly including a
`a predetermined windshield surface to make progressive
`wiper element, a ?exible spring backbone element con
`nected to the wiper element, attaching means adjacent
`“wrapping” pressure contact from ends to center as a pre
`determined normal pressure loading is gradually applied
`the center of said backbone element, said backbone ele
`through said attaching means, said spring rate increasing
`ment having coordinated length, section Width, thickness,
`as a greater than linear function of distance inwardly
`modulus of elasticity and free form longitudinal curva
`toward the center.
`ture exceeding any subtended windshield curvature and
`5. A windshield wiper blade assembly including a
`including progressive dimensional variations providing a
`wiper element, a ?exible spring backbone element con
`parabolic eifect in spring rate normal to the windshield
`nected to the wiper element, attaching means adjacent
`surface adapted in engagement in a normal direction
`the center of said backbone element, said backbone ele
`against a predetermined windshield surface to make
`ment having coordinated length, section width, thickness,
`progressive “wrapping” pressure contact from ends to
`modulus of elasticity and free form longitudinal curvature
`center as a predetermined normal pressure loading is
`25
`exceeding any subtended windshield curvature and in cluding progressive dimensional variations providing a
`gradually applied through said attaching means, said
`spring backbone element having a rib of varying depth
`providing a spring rate increasing approximately as the
`square of the distance inwardly toward the center.
`9. A windshield Wiper blade assembly including a
`a wiper element, a ?exible spring backbone element con
`nected to the wiper element, attaching means adjacent
`the center of said backbone element, said backbone ele
`ment having coordinated length, section width, thickness,
`modulus of elasticity and free form longitudinal curvature
`exceeding any subtended windshield curvature and includ
`ing progressive dimensional variations providing a para
`bolic effect in spring rate normal to the windshield surface
`adapted in engagement in a normal direction against a
`predetermined windshield surface to make progressive
`“wrapping” pressure contact from ends to center as a
`predetermined normal pressure loading is gradually ap
`plied through said attaching means, said spring backbone
`element having a pair of ribs of varying depth providing a
`spring rate increasing approximately as the square of the
`distance inwardly toward the center.
`'
`
`parabolic e?ect in spring rate normal to the windshield
`surface adapted in engagement in a normal direction
`against a predetermined windshield surface to make
`progressive “wrapping” pressure contact from ends to
`center as a predetermined normal pressure loading is
`gradually applied through said attaching means, said
`spring backbone element having a spring rate increasing
`approximately as the square of the distance inwardly
`toward the center.
`6. A windshield wiper blade assembly including a
`wiper element, a ?exible spring backbone element con
`nected to the wiper element, attaching means adjacent the
`center of said backbone element, said backbone element
`having coordinated length, section width, thickness, modu
`lus of elasticity and free form longitudinal curvature ex
`ceeding any subtended windshield curvature and including
`progressive dimensional variations providing a parabolic
`effect in spring rate normal to the windshield surface
`adapted in engagement in a normal direction against a
`predetermined windshield surface to make progressive
`“wrapping” pressure contact from ends to center as a
`predetermined normal pressure loading is gradually ap
`plied through said attaching means, said spring backbone
`9/41 Zierer ____________ .. l5—250.23
`2,254,343
`element having a varying width of section de?ned by sub
`stantially parabolic edge curvature providing a spring rate
`3/52 Carson ___________ __ 15—-250.40
`2,589,339
`2,654,597 10/53 Barenyi ____________ __ 267—47
`increasing approximately as the square of the distance
`3,029,460
`4/62 Hoyler ___________ __ 15—25 0.42
`
`inwardly toward the center. 7. A windshield wiper blade assembly including a
`FOREIGN PATENTS
`4/35 Great Britain.
`427,383
`5/48 Great Britain.
`619,320
`785,865 11/57 Great Britain.
`820,156
`7/37 France.
`
`40
`
`45
`
`wiper element, a ?exible spring backbone element con
`nected to the wiper element, attaching means adjacent
`the center of said backbone element, said backbone ele
`ment having coordinated length, section width, thickness,
`modulus of elasticity and free form longitudinal curvature
`exceeding any subtended windshield curvature and in
`
`References Cited by the Examiner
`UNITED STATES PATENTS
`
`50
`
`55
`
`60
`
`CHARLES A. WILLMUTH, Primary Examiner.
`
`Costco Exhibit 1004, p. 6
`
`