United States Patent [191
`Swanepoel
`
`lllllllllllllllllIIHIlllllllllllllllllllllllllllll]Illllllllllllllllllllll
`US005485650A
`5,485,650
`Patent Number:
`[11]
`Jan. 23, 1996
`[45] Date of Patent:
`
`[54] WINDSCREEN WIPER WITH ELONGATED,
`CURVED BACKBONE
`
`[75] Inventor: Adriaan R. Swanepoel, Pretoria, South
`Africa
`
`[73] Assignee: Adriaan Retief Swanepoel, South
`Africa
`
`[21] Appl. No.: 137,769
`[22] Filed:
`Oct. 19, 1993
`[30]
`Foreign Application Priority Data
`
`Oct. 23, 1992 [ZA]
`
`South Africa ......................... .. 92/8225
`
`[51] Int. Cl.6 ...................................................... .. B60S 1/38
`[52] U.S. Cl. ................................... .. 15/250.43; 15/250.48;
`15/250.361
`[58] Field of Search .......................... .. 15/250.20, 250.42,
`15/250.36, 250.02, 250.41, 250.40, 250.37,
`250.38, 250.39, 250.01; D12/155
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3/1952 Carson ............................... .. 15/250.36
`2,589,339
`3,029,460 4/1962 Hoyler
`.. 15/250.36
`3,104,412
`9/1963 Hinder
`15/250.42
`3,192,551
`7/1965 Appel .... ..
`.. 15/250.36
`3,480,986 12/1969 Forster
`.. 15/25042
`3,751,754
`8/1973 Quinlan ..
`15/250.42
`3,780,395 12/1973 Quinlan ..
`15/250.42
`3,872,537
`3/1975 Bianchi ..
`.. 15/250.42
`3,881,214 5/1975 Palu ................................... .. l5/250.42
`
`6/1977 Appel ................................. .. 15/250.42
`4,028,770
`4,063,328 12/1977 Arman
`15/250.42
`4,102,003
`7/1978 Hancu ................. ..
`151250.42
`4,127,916 12/1978 van den Berg et a1.
`.. 15/250.42
`4,339,839
`7/1982 Knights ..
`15/250.36
`4,343,063
`8/1982 Batt ......... ..
`15/250.42
`4,587,686
`5/1986 Thompson
`15/250.42
`4,807,326
`2/1989 Arai ................................... .. l5/250.42
`
`FOREIGN PATENT DOCUMENTS
`
`4/1983 France.
`2515121
`9/1974 Germany.
`2311293
`2/1975 Germany.
`2336271
`2350302 4/1975 Germany.
`2353368 5/1975 Germany.
`1012902 5/1963 United Kingdom.
`1395918 5/1975 United Kingdom.
`
`Primary Examiner——Gary K. Graham
`Attorney, Agent, or Firm-Cushman Darby & Cushman
`
`[57]
`
`ABSTRACT
`
`A windscreen wiper includes an elongate curved backbone
`which is of a resiliently ?exible material and which has a
`connecting formation at a position intermediate its length for
`connection to a displacing and force applying member. The
`backbone has a free-form curved pro?le in a plane, thereby
`to de?ne a transverse axis perpendicular to the plane. The
`backbone further has a suitably varying transverse cross
`sectional pro?le along its length such that if it is clamped at
`its connecting formation and a test force of 1N applied at a
`tip in a direction that is parallel to the transverse axis, the tip
`is displaced less than 1.0 mm.
`
`10 Claims, 2 Drawing Sheets
`
`Costco Exhibit 1006, p. 1
`
`

`
`US. Patent
`
`Jan. 23, 1996
`
`Sheet 1 of 2
`
`Costco Exhibit 1006, p. 2
`
`

`
`US. Patent
`
`Jan. 23, 1996
`
`Sheet 2 of 2
`
`5,485,650
`
`FIG 4
`
`2'5“
`
`RADIUS OF
`)
`URVATUR (
`20 C
`E m
`
`0 5
`
`-2‘0
`
`45
`
`lb
`'5
`o
`--'5
`-i0
`DISTANCE FROM CENTRE (cm)
`FIG 5
`
`:5
`
`2‘0
`
`Costco Exhibit 1006, p. 3
`
`

`
`1
`WINDSCREEN WIPER WITH ELONGATED,
`CURVED BACKBONE
`
`5,485,650
`
`2
`
`FIELD OF INVENTION
`
`This invention relates to a windscreen wiper and more
`particularly to an elongate curved backbone for a wind
`screen wiper which is of a suitably resiliently ?exible
`material.
`
`SUMMARY OF THE INVENTION
`
`According to a ?rst aspect of the invention there is
`provided a windscreen wiper which includes
`an elongate curved backbone which is of a resiliently
`?exible material and which has a connecting formation at a
`position intermediate its length for connection to a displac
`ing and force applying member;
`the backbone having a free-form curved pro?le in a plane,
`thereby to de?ne a transverse axis perpendicular to the
`plane; and
`the backbone having a suitably varying transverse cross
`sectional pro?le along its length such that if it is clamped at
`its connecting formation and a test force of 1N applied at a
`tip in a direction that is parallel to the transverse axis, the tip
`is displaced less than 1.0 mm.
`Preferably, it is displaced less than 0.7 mm. Most pref~
`erably, it is displaced less than 0.25 mm.
`The tip to which the test force is applied may be displaced
`a distance
`
`20
`
`25
`
`30
`
`35
`
`0.7
`
`(1)
`
`and Ia(x) is the moment of inertia about the z-axis at a
`position x along the backbone, R(x) is the radius of curva
`ture of the backbone at position x, and Iyy(x) is the moment
`of inertia about the y-axis at position x.
`Preferably ZT<0.5 mm.
`The windscreen wiper may include a wiper blade attached
`to the backbone.
`Persons skilled in the art will appreciate that the backbone
`will have a concave side and a convex side, the wiper blade
`being attached to the concave side and the displacing and
`force applying member on the convex side.
`The backbone may be of metal such as spring steel and
`may be in the form of a single homogenous strip or may be
`in the form of a laminate.
`The connecting formation may be centrally located or the
`backbone may be asymmetrically arranged about the con
`necting formation.
`The distance from the connecting formation to each tip
`may be at least 200 mm.
`Those skilled in the art will appreciate that Izz(x) and
`Iyy(x) are determined by the transverse dimensions of the
`backbone at any position along its length. In most cases, the
`backbone will have a regular cross-sectional pro?le which
`may, for example, be rectangular or ellipsoidal. In most
`instances, the backbone will have a width and a thickness. It
`will be understood that the width dimension (b) will be that
`dimension which extends perpendicularly to the plane of
`curvature and the thickness (h) will be the dimension which
`lies in the plane of curvature.
`It can be shown, with a backbone which has a rectangular
`cross-section at all positions along its length, that
`
`1,,(10 =____bs<g’*afg>
`
`3
`In“) : (be) *1; (x)
`
`Thus, with a rectangular cross-section,
`
`2171:] sin I L dx dx
`
`X
`
`1
`
`0 13001120’)
`
`l
`
`0
`
`<3)
`
`(4)
`
`(5)
`
`Preferably, said displacement may be
`
`ZE< ( 30-17531) 0.625
`
`where l is the cantilever length of the backbone from the
`connecting formation to the tip to which the test force is
`applied and where ZE is the displacement in m if 1 is in
`meters.
`The windscreen wiper may include a wiper blade attached
`to the backbone. The backbone may be of metal. Further, the
`backbone may be in the form of a single homogenous strip
`or in the form of a laminate.
`The connecting formation may be centrally located. The
`backbone may be asymmetrically arranged about the con
`necting formation. The distance from the connecting forma
`tion to each tip may be at least 200 mm.
`According to a second aspect of the invention, there is
`provided
`a windscreen wiper which includes
`an elongate backbone which is curved in a plane, is of a
`resiliently ?exible material and which has a connecting
`formation at a position intermediate its length for connection
`to a displacing and force applying member;
`the backbone de?ning an x—y plane, a z-axis extending
`perpendicularly from the x—y plane;
`the backbone having a suitably varying cross-sectional
`pro?le along its length and a suitable free-form curvature,
`such that a double integral ZT is less than 1.0 mm, where
`
`40
`
`45
`
`50
`
`55
`
`60
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention is now described, by way of an example,
`with reference to the accompanying drawings, in which:
`FIG. 1 is a schematic perspective view from above of a
`windscreen wiper in accordance with the invention;
`FIG. 2 is a side elevation of the windscreen wiper in an
`unloaded, free-form condition;
`FIG. 3 is a schematic sectioned view of the wiper along
`lines III—III in FIG. 2;
`FIG. 4 shows schematically the axial convention utilised
`in this speci?cation; and
`FIG. 5 shows graphically the variation in the radius of
`curvature of the backbone of the wiper in its free-form
`condition.
`
`DETAILED DESCRIPTION OF THE DRAWINGS
`
`65
`
`A symmetrical windscreen wiper in accordance with the
`invention is referred to generally by reference numeral 10.
`It includes a spring backbone 12 and a rubber wiper blade
`
`Costco Exhibit 1006, p. 4
`
`

`
`5,485,650
`
`15
`
`20
`
`25
`
`30
`
`35
`
`3
`14. The backbone 12 has a centrally located connector 16 for
`releasably connecting the wiper 10 to a spring loaded wiper
`arm (not shown). The connector 16 could be of any suitable
`type. The backbone 12 has suitable attachment formations
`(also not shown) whereby the blade 14 is securely attached 5
`to the backbone 12, or the blade 14 is glued to the backbone
`12.
`The spring backbone 12 is preferably made from spring
`steel and tapers both in width and thickness from its centre
`towards its free ends or tips. The backbone is pre~curved
`longitudinally with a predetermined radius of curvature (R)
`at every point in its length. The backbone 12 de?nes a plane,
`which is de?ned by the sheet of paper in FIG. 2. As indicated
`in FIG. 4, a median line 18 of the backbone 12 lies in the x—y
`plane with the x axis extending tangentially at the centre of
`the backbone 12. The z-axis de?nes a transverse axis per
`pendicular to the plane in which the free-form curved pro?le
`of the backbone 12 lies.
`The backbone 12 has a rectangular cross-sectional pro?le
`at all points along its length. Thus, the backbone 12 has a
`width b and a thickness h as indicated in FIG. 1. It will be
`appreciated that the width b is the dimension parallel to the
`z-axis and the thickness h is the dimension perpendicular to
`the tangent at each point.
`The free-form radius of curvature R of the backbone 12 is
`indicated in FIG. 2 and the variation thereof is shown in FIG.
`5.
`In the example shown, the backbone has a total
`length L=450 mm
`a modulus of elasticity=207><l09 N/m2
`thickness at the centre of the backbone=l.29 mm
`thickness at the tips=0.22 mm
`width at the centre=l1 mm, and
`width at the tips=6 mm.
`The backbone tapers uniformly in both thickness and
`width in a straight line manner from its centre to its tips.
`If the wiper is securely clamped at its connector 16 and a
`lateral force applied at either tip, parallel to the Z-axis, of
`1N, the lateral displacement of the tip in the Z direction is
`0.28 mm allowing for experimental errors.
`The value of 25 (as determined in the equation 1 above)
`is 2.03 mm
`Similarly, if the value of ZTR (from equation 5 above) is
`computed it will be found to be 0.28 mm.
`I claim:
`1. A windscreen wiper which includes
`an elongate backbone which is curved in a plane, is of a
`resiliently ?exible material and which has a connecting
`formation at a portion intermediate its length for con
`nection to a displacing and force applying member; and
`a wiper blade attached to the backbone;
`the backbone having ?rst and second longitudinal ends
`and a mounting surface de?ned along the length thereof
`from said ?rst longitudinal end to said second longi
`tudinal end, said backbone being secured to said wiper
`blade, said curved backbone being substantially coex
`tensive with said wiper blade, said backbone having a
`transverse cross-sectional pro?le de?ning a thickness
`and a width thereof, the thickness of said backbone
`being greatest at said intermediate portion and gradu
`ally decreasing along at least a ?rst portion of said
`backbone, which is de?ned between said connecting
`formation and said ?rst longitudinal end,
`
`4
`the backbone having a free-form curved pro?le in a plane,
`whereby the backbone de?nes an x-y plane, a z~axis
`extending perpendicularly from the x-y plane;
`the backbone having a suitably varying cross-sectional
`pro?le along its length and a suitable free-form curva
`ture, such that a double integral ZTis less than 1.0 mm,
`where
`
`.
`l
`zr= 0 sin
`
`law
`1
`
`o-———R(x) [Wm dx
`
`dx
`
`where l is a cantilever length of the backbone from the
`connecting formation to the ?rst longitudinal end of the backbone and Izz(x) is the moment of inertia about the
`
`z-axis at a position x along the backbone from the
`connecting formation, R(x) is the radius of curvature of
`the backbone at position x expressed in metres, and
`Iyy(x) is the moment of inertia about the y-axis at
`position x.
`2. The windscreen wiper as claimed in claim 1, in which
`ZT is less than 0.5 mm.
`'
`3. The windscreen wiper as claimed in claim 1, in which
`
`the backbone is of metal. 4. The windscreen wiper as claimed in claim 1, in which
`
`the backbone is in the form of a single homogenous strip.
`5. The windscreen wiper as claimed in claim 1, in which
`the connecting formation is located at about a longitudinal
`center of said backbone.
`6. The windscreen wiper as claimed in claim 1, in which
`the backbone is symmetrical with respect to the connecting
`formation.
`7. The windscreen wiper as claimed in claim 1, in which
`the distance from the connecting formation to each longi
`tudinal end is at least 200 mm.
`8. The windscreen wiper as claimed in claim 1, in which
`the transverse cross-sectional pro?le of the backbone has the
`same shape along the length of the backbone and varies in
`size.
`9. The windscreen wiper as claimed in claim 8 which has
`a rectangular cross-section with the backbone having a
`width dimension b(x), a thickness dimension h(x) and a
`radius of curvature R(x) at each point x along its length and
`
`45 50
`
`55
`
`10. The windscreen wiper as claimed in claim 1,
`wherein said wiper blade has ?rst and second longitudinal
`ends, a wiper edge de?ned along the length thereof
`from said ?rst longitudinal end to said second longi
`tudinal end, and a substantially ?at mounting face
`de?ned along the length thereof from the ?rst longitu
`dinal end to the second longitudinal end and opposed to
`said wiper edge; and
`said mounting surface of said backbone is substantially
`?at, said backbone being secured to said wiper blade so
`that said mounting surface is in opposed facing relation
`to and in substantially continuous contact with said
`mounting face of said wiper blade.
`
`* * * * *
`
`Costco Exhibit 1006, p. 5