Патент USA US3077003код для вставки
Feb. l2, 1963 J. w. ANDERSON 3,076,993 WINDSHIELD WIPER BLADE Filed Oct. 24, 1958 2 Sheets-Sheet 1 (Kim _ INVENTOR JOHN W. A NDERsoN BY/a'f. MMM A Q0. 711C 1J, « c. S. P ’- 'f ATTORNEYS Feb, 12, 1963 J. w. ANDERSON 3,076,993 WINDSHIELD wIPER BLADE Filed oct. 24, 195e 2 Sheets-Sheet 2 __ ' YzNvmTok. JOHN W. ANDERSON :SY/¿12W , . Q_ ¿ggg 7241?», C', 5. TORNEVS United States Patent Gtiîce fi envases YVINDSHEELD ‘lil/EPEE? BLADE John W. Anderson, 57S Broadway, Gary, Antl. Filed Get. 2d, i958, hier. No. ’769,404 i3 (Claims. (Cl. .l5-_256.4% This invention relates to a windshield wiper assembly and more particularly to an improved wiper assembly for wiping dat, curved, and/ or wrap-around Windshields and to an improved method of making same. An object of the invention is to provide simple means by which the relative ilexibility of various longitudinal portions of a flexible backing strip for a wiper for curved windshields may be varied to conform to varying curva itures of the windshield. A further object of the invention is to provide a method by which a portion of the ileXor, or backing strip, of a wiper blade tor curved windshields, may be in creased in effective length and in flexibility without sub stantially increasing the over-all length of material re~ quired to produce the flexor, or backing strip, thus to attain greater iiexibility in said portion for more ready and more extended response to wiper arm pressures trans mitted thereto. A further object of the invention is to provide a method of manufacture whereby the ilexibility of a pre determined portion of a flertor, or backing strip, may be changed by forming such portion so as to increase its effective length i i e at the same time changing the thick ness of the material in said portion, whereby to alter the resistance of the tlexor, or backing strip, to flexing under pressure transmitted thereto from the wiper arm. Another obiect of the invention is to provide a flexor, or backing strip, in which the flexibility oi diíîerent por tions thereof is reduced or increased respectively to pro vide a combination of longitudinal and transverse defor mations of the material from which sai-d strip is made. A further object of the invention is to provide means by which variations in the degree of conformability ci different longitudinal portions of a wiper blade, in main taining contact of said blade, throughout its length, with la windshield surface of varying degrees of curvature, may be accomplished without the employment of aux iliary springs or of members iniluenced thereby. A further object of the invention is to facilitate con formity of a wiper blade to varying degrees of curvature of a surface to be wiped without substantially varying the width of the ilexor, or backing strip, throughout its Bßîëßäß Patented Feb. l2, liëâß 2 In the drawings: FIGURE l is a side View in elevation of a preferred form of my improved windshield wiper blade assembly as applied to a windshield; FIGURE 2 is an enlarged view of the right-hand por tion of the full assembly of FIGURE. l removed from the windshield; FLJURE 3 is a bottom view of the backing strip or iiexor of FiGURE l together with the underengaging slid ing claws at the ends of the pressure-transmitting means; FIGURE 4 is a side view of the ilexor of FIGURE 3; FIGURE 5 is a cross-sectional view taken along the line 5--5 of FÍGURE 2; FÃ‘GURE 6 is a partial cross-sectional View taken along the line 6_6 of FIGURE 2; FlGURE 7 is a side view of a modified form of my irn proved windshield wiper blade assembly; FiF-,URE 8 an enlarged view of the right-hand por tion of the full assembly of FIGURE 7; FEGURE 9 is a bottom view of the backing strip or flexor of FÍGURE 7 together with the underengaging slid ing claws at the ends of the pressure-transmitting means; FlGURE l0 is a side view of the iiexor of FIGURE 9; FEGURE ll is a cross-sectional view taken along the line ìl--ll of FEGURE 8; FEGURE l2 is a cross-sectional view taken along the line l?, l2 of FEGURE 8; and FlGUlìE i3 is a cross-sectional view taken along the line 13a-i3 of FlGURE 8. Referring more particularly to FIGURES l~6 of the drawings, the windshield wiper assembly is generally desig nated lil and is comprised of a wiper blade ll and a pressure~distributing device l2. The wiper blade l1 is comprised of an elongate resiliently tlexible support, back~ ing, or fleXor T13 and a resilient rubberlike wiping element ld carried by the support. The pressure-distributing or transmitting device l2 may be constructed in various ways, but as herein illustrated preferably includes a pair of cor responding secondary yokes l5 and 16 having their ends slidably connected to the blade l1, a primary yoke 17 having its ends connected to intermediate portions of the secondary yokes, and a connector 1S carried by the pri mary yoke for connection with the end portion of a windshield wiper arm i9. The fleXor i3, as will be described in detail hereinafter, is elongate and has corresponding end portions 2l and 22 and an intermediate portion 23 of a greater width than the end portions. This variation in width forms shoulders length. which provide longitudinally spaced abutment means 2,5 50 A further object of the invention is to provide a flexor, and 2.6. The support or llexor 13 is preferably provided or backing strip, for wiper blades for nonflat windshields with an elongate narrow slot 28 terminating short of the in which both linear and transverse deviations in the ends of the support to provide connecting or hinge portions shape of the material used may be eiîected economically 29 whereby longitudinal parallel side portions 30, 31 of in a single forming operation. the support can be spread apart to enlarge the size of the A further object of the invention is to provide an im 55 slot so that the resilient element 14 can properly be lo proved wiper blade, a portion of which, adjacent an eX cated therein, after which the longitudinal portions 3i), 31 tremity thereof, conforms readily to comparatively abrupt are released to cause such portions to interlock with the curvatures in the outwardly extending portions of the element ld. Due to the character of the support or flex surface to be wiped. or, the blade is primarily limited to ilexation or movement 60 A still further object of this invention is to provide a in a direction substantially perpendicular to a surface of wiper assembly that is suiliciently flexible to conform to the windshield to be cleaned. the surface being wiped and is sufficiently inflexible in por The wiping element 14 is provided with. an attaching tions thereof to prevent such portions :from lifting from or back portion 32 and a wiping portion 33 which is the windshield, particularly under the influence of wind joined to the attaching portion by an intermediate re currents and the like. stricted portion or web 34 so as to permit tilting of the And yet another object of this invention is to provide wiping portion. The attaching portion is provided with a an improved wiper assembly of simple construction and pair of corresponding grooves 35, one being located adja operation, which is not only more economical to manu cent each side of the attaching portion in a predetermined facture, but also is etlicient in use. Other objects and advantages of the invention will be 70 position so that they lie substantially in the same plane. The grooves 35 receive the interrnarginal edge portions of come evident after considering the description hereinafter set forth in conjunction with the drawings annexed hereto. the longitudinally extending portions 30, 3l of the support 3,076,993 ¿i El sembled with the pressure-transmitting device 12. The re« for holding the support or flexor is and element llt sulting ñexor 13 has the usual degree of flexibility assembled. throughout the uncorrugated portion of the liexor and The secondary yokes 15 and lid are preferably identical has a substantially increased degree of flexibility through in design and construction. The inner end of the base wall of each secondary yoke is formed to provide a trans Ul out the corrugated end portion Z2 of the tlexor. The incorporation of the corrugations 4,2 into the ilexor‘ verse arcuate or curved end 35 and a pair of correspond has the effect of increasing the effective length of thel ing ears or claws 37. The outer end of each secondary ilexor Without substantially increasing or decreasing the> yoke is provided with a shroudlike end wall 38 which actual length thereof. In one preferred method of form» serves to conceal the ends of the support. The outer end ing the corrugations into the tiexor, two matching corÍ of each of the secondary yokes l5, i6 is also provided rugated dies, equal in length to the desired length of the corrugated portion of the flexor, are simultaneously' forced together against the interposed end portion of the.` with a pair of ears or claws 39 spaced inwardly from the end wall 38. When assembled with the blade, the pairs of ears or claws 37 and 3‘9 of the yoke l5 extend over the reduced extremity 2l of the support or flexor 13 and 'the corresponding ears or claws 37 and 39 of the yoke 16 similarly extend over the extremity 22 of the ilexor. increments of the end portion of the ñexor areI simultaneously stretched and bent between the dies to* thereby form successive ridges and valleys resulting inv the corrugated shape. 'the stretching of the metal of the end portion adds effective length to the liexor, but due to the bending into the corrugated shape the actual length support or ilexor to effect a sliding feature between the yokes and the support. rThe secondary yokes 1S and Elo are preferably assembled with the support by merely sliding the yokes inwardly along the extremities of the 20 of the flexor remains substantially the same. Simultane ously, the stretching of the metal of the corrugated por support until the inner ends of the yokes engage the abut tion also reduces the thickness of the metal in the corru ment means, after Which the primary yoke 17 is attached to the secondary yokes in a manner shown and described gated portion by comparison to the uncorrugated portion or portions of the flexor. r[he result of both the increase in the effective length and the reduction in the thickness of the said end portion of the flexor is to substantially in my copending application Serial No. 609,633., filed September 13, 1956, now Patent No. 2,955,3l3. It is to be understood that the invention is not intended increase the flexibility of said corrugated end portion of to be limited to the above-described pressure-transmitting `system or to the particular shouldered ilexor, these ele ments being shown and described for illustration pun the iiexor. poses only. yoke i5, is therefore more flexible in a direction substan The corrugated end portion 22;, beneath the secondary ' tially perpendicular to the plane of the ñexor and, when The flexible support or flexor i3 is provided with a means whereby different degrees of flexibility are intro duced into the fiexor during manufacture of the ñexor to assembled with the rubber element of a blade, results in a blade having different degrees of flexibility at prede« ermined portions along its length to meet the demands to be placed upon the wiper assembly with which the ñexor is to be used. satisfy the particular wiping requirements of the blade assembly with which the lieXor is to be used. rthat is, on a windshield with an extreme curvature, particularly on the outboard side portion thereof, it is necessary for Since the corrugations ¿i2 may be formed simultaneous~4 the wiper blade 11 comprising the wiping element 1.4% and ly by the same stroke of the press that cuts or forms other’ the ilexor 13, lying substantially beneath the outwardmost parts of the ñexor, as the material is fed progressively secondary yoke 16, to flex or bend in the plane lying sub 40 into the press, the corrugating operation adds no cost stantially perpendicular to the surface of the Windshield to the production of the flexor. Thus, the ilexor embod~ ied in the present invention produces a substantially im to a much greater extent than for older type curved wind proved result when incorporated in a wiper assembly shields. By providing the iiexor 13 with a more freely ñexible portion in the area where greater and more severe without in any way increasing the cost of producing the flexing isY required and by maintaining the balance of the flexor. Likewise, an improved reiill assembly of the type fiexor or support with a lesser degree of flexibility, a wiper described and claimed in U.S. Patent No. 2,782,445 re blade is produced that conforms throughout its length to more sharply curved surfaces of a windshield, such as sults from the incorporation in said reñll of the inventive concept above described. are encountered in wrap-around type windshields. In one preferred form, such as shown in FlGURES 1-6, inclusive, the one-piece ilexor iff is shown with the by the wiper assembly lll are those traversed by the outer end portion of the blade, where reduced resistance to claws 37, 39 of each secondary yoke l5, le embracing the `edge portions ofthe reduced end portions 2l, Z2, the blade to conform to the surface of the windshieid be respectively, of the ñexor. The end portion 22 of the ing wiped, The surface area of the glass traversed by the ñeXor 13 has corrugations 42 formed therein in a direc mid-portion of the blade, i.e., that portion lying between. the respective inner claws 37, 37 of the secondary yokes'y l5, lo, is usually less abruptly curved and, therefore, yless llexibility in the íiexor is required. The mid-portion. Maximum curvatures of the windshield encountered iiexure, occurring under the outer secondary yoke, assists tion lying substantially perpendicular to the longitudinal axis of the flexor 13 throughout substantially the length of said reduced end portion 22. The corrugations ft2, in the preferred showing, are preferably of a wave formation of the blade wipes the somewhat more critical area'of the-v having substantially straight, parallel, regular, and equal-v 60 windshield directly in the line of vision of the driver and ly curved ridges 43 and valleys 4d, as best shown in FÍG URES 2 and 4._ The corrugations 42 caribe produced during the forming of the flexor and have the effect of reducing the resistance of the end portion 222V to ñexing, which has a greater range of adaptability to purposes de 65 is the portion ordinarily more susceptibie to lifting oif' the glass through pressure of air currents encountered> against the windshield indriving. it has been found that by maintaining, in that portion or segment of the iiexor: lying between the secondary yokes, the prevailing stand y?ned herein than does reducing either the width‘or the thickness of the material of which the Ílexor is made. ards'of resistance to flenure, with reiation to the length, design, and dimensions of the blade assembly, that seg ment has satisfactory resistance to normal windlift and As referred to above, fleXor 13 may be made from a piece of material of substantially uniform standard thick otherwise, under normal» driving conditions, remains in ness normal for a particular wiper assembly. The trans~ 70 effective opertative contact with the windsbieid. ' it per: verse corrugations 42 herein proposed are added simul haps should be pointed out that the predetermined pres taneously to each side portion 3i?, 3l throughout substan sures, at the foar contacts oi the pressure-distribating tially the length of the end portion 22 of the tiener so as assembly with the tiener, remain substantially constant, to preferably terminate just short of the inner claws 37 so that while a ni and outer claws 39 of the secondary` yoke il@ when spends _effectively to sha n flexible segment of the e 3,076,993 5 each end of each relatively more flexible portion are normal, predetermined pressures that substantiaily insure satisfactory conformity of the wiping edge of the rubber element to the windshield throughout the entire length of that element and throughout the entire stroke of the blade. it will be understood that when the iiexor (as has been practiced heretofore) is of the same thickness through out its length the need for greater iiexibility to cause the portion e2 and a wiping portion 63 which is joined to the attaching portion by a web dit so as to permit tilting, of the wiping portion relative to the attaching portion. The attaching portion 62 is provided with a pair of correspond ing grooves 66, one being located in each side of the at taching portion in a predetermined position so that they lie substantially in the same plane. Near each end of each groove 6e in the attaching portion 62 of the element 5S is an abutment 67 extending transverse to the base "lade to conform to the sharper outer curvatures of a 10 of the groove whereby the ends of the grooves are closed. wrap-around Windshield might force a decision to adopt Grooves 66, with the ends closed as at 7, are sometimes a uniform thickness ot the iiexor, generaliy too thin to referred to as blind grooves or pockets. hold the middle portion of the rubber ñrmly enough to FÉGURES 9 and l() illustrate the modified form of ílexor the glass to prevent windlift and chatter of the blade at 54 adopting the teaching ot` my invention to a two-piece higher car speeds. Thus, it may be seen that no uniformly 15 type ilexor. The lienor .f5-t has two unattached indepen desirable compromise in ñexor thickness as between these dent sides 7i, 72 each with corresponding end portions extremes has been readily attainable in the art. ri`he 73, '74 and an intermediate portion 7S delineated from the present invention, however, permits any desired diiîer end portions by abutment surfaces 77, 7S formed in one ential in flexibility of any predetermined longitudinal edge of each side ’71, 72. rEhe end portions have cor portions of the iiexor, to promote conformity and prevent 20 rugations ’79, which are similar to the corrugations of “mid lift” of the blade, without adding to the cost of FÍGURES l-6, and are comprised of substantiaily straight, producing the blade. parallel, regular, and equally curved ridges 3€) and val Most windshields currently in use and projected for leys 81. future use have surface portions in the vicinity or” the wiper The respective sides 7i, 72 of the tiexor are partially shaft which are substantially flat or are only moderately 25 nested in the grooves 6e with the edges containing the curved so that one end portion of the blade assembly need abutments 77, 73 projecting outwardly from the wiping not be any more iiexible than the central portion of the element 55S. Each secondary yoke 5'7 and 5S has a pair blade. The one preferred form shown in FIGURES l of claws S3 formed on the inner end portion 8d thereof to 6 is of the type just described, namely, one end portion and a pair of claws 85 formed on the outer shrouded end Zi is inherently more tiexible than the mid-portion 23 of 30 portion 8o thereof. ’ille claws 83 and 35 on secondary the iiexor and blade. The other end portion Z2 of the yoke 57 engage around the edges of the reduced end por flexor is corrugated at 5.12 to increase the flexibility thereof tions ‘73 of the sides of the iiexor 5d, and the claws £3 so that the blade in the vicinity of the corrugations more and 5s“ on the other secondary yoke engage around readily conforms to the sharp wrap~around curvatures of the other reduced end portions '.74 of the sides of the 35 iiexor the windshield. for hoiding the sides 721, 12 of the iicxor Se ln the windshield wiper replacement market, there are seated in the blind grooves ed. The abutments d? at the a 1:arge number of wiper blades sold that may be installed ends of the grooves en prevent the sides 7i, 72, of the on a wiper arm as readily with one end or" the blade out iie‘xor from sliding out of the ends of the rubber eie ward as with the other end outward. it is, therefore, de rnent. The primary yoke 59 is attached to the yoices 57, sirabie to provide, under each secondary yoke, the same 40 Sis for holding the pressure-transmitting device bf2 assen ñexibility since it is impractical to rely upon servicemen bled on the tlexor 5e of the wiper biade 5l. or car owners to select one or the other end of the blade to in the modiiied form or” my invention, the corrugated install in the outboard position. Accordingly, it is to be rtion 'T9 terminates just short of the inner and outer qu understood to be within the scope of this invention to have f fait, d5, respectively, of the secondary yolres v57, Sti. corrugations ft2 at either end portion, at both end por 45 ne folies 57, are free to slide, within operative limits, tions, or at any larger or smaller increment of the length on said flerror. The ridges fit? of the corrugations 79 are of the blade to arrive at any desired result with respect to adapted to engage the one wall of the grooves 66 and varying degrees of iiexibility throughout the length of the valleys Si of the corrugations are adapted to engage the blade. the other wali of the grooves o6 during normal conditions in my copending application Serial No. 710,598, ¿ed of use of the wiper blade and wiper assembly. January 23, 1958, now abandoned, l have disclosed a way The modiiication of FEGURES 7-13 performs all of to increase the resistance of portions of a iieXor to flexing ’no novel functions attributed to the preferred form shown in a particular plane by adding longitu inally disposed. channels or ribs in the sides or” the ilexors. The channels serve as stifiening members so as to decrease the tieni bility of the portions receiving the channels. it is to be in 1_6. The corrugations ’79 can be added to the liexor 5d at no extra cost to produce a blade that readily conforms to surfaces to be wiped. Having thus described my invention, it is obvious that understood to be included within the scope or“ this in various modiíications may be made in the same without vention to incorporate transverse corrugations in a portion departinr.7 from the spirit of the invention, and, therefore, or portions of a ñexor to increase the ñexibiiity of that i do not wish to be understood as limiting myself to the portion or portions of the llexor and also to incorporate 60 exact form, construction, arrangement and combination longitudinal channels in another portion or portions of of parts herein shown and described. the ñeXor to reduce the flexibility of that portion or por E claim: tions of the iiexor. l. A iiexible backing member for a windshield wiper FÉGURES 7-13 illustrate a modified form of my in blade adapted to wipe curved windshields, said member vention wherein a wiper assembly Si) comprises a wiper 65 having at least two adiacent longitudinal portions with a blade 5l and a pressure-transmitting device 52. The wiper plurality of undulations extending above and below the blade 5l is comprised of an elongate ñexible support or plane of said backing member along axes lying substan ilexor 54» and a resilient rubberlike wiping element 55 car tially perpendicular to the longitudinal axis of one of ried by the support. The illustrated pressure-transmitting said portions for reducing resistance to ñening in one of device 52 is comprised of a pair of secondary yokes 57, 70 said portions. 53 and a primary yoke 59 connected to the intermediate 2. in a wiper blade for curved ‘windshielda a resilient portions of the yolzes 57, 53. A connector 6b` is carried rubberliiie elongate wiping element, a resiliently and re by the primary yoke for attaching the wiper assembly to a windshield wiper arm. The wiping element 55' is provided with an attaching versely ñexible elongate pressure-transmitting backing strip associated coactively therewith, said backing strip having a pluraiity of readily iiexible adjacent and integral andasse 7 portions substantially equal in width, at least one of said formed in at least one of said portions whereby to reduce portions having corrugations thereon, said corrugations the resistance to flexing in said last-named portion, said comprising a plurality of undulations extending above and below the plane ot said backing member along axes sub stantially perpendicular to the longitudinal axis of said portion for substantially reducing the resistance of that portion to flexing relative to an adioining portion of the backing strip whereby to produce in the blade a greater corrugations being defined by continuous adjacent de formations `out of the plane of the backing strip. 9. Fexible backing means for a windshield wiper ele ment which is adapted to wipe a windshield having an irregular surface, said tlexible backing means being elon and adapted to be disposed generally coextensive with the wiper element, said ilexible bacl'ing means having at least one longitudinal portion provided with a. plurality of transversely disposed undulations extending above and below the plane of said longitudinal portion for reducing resistance to llexure in said longitudinal portion. inherent ability to conform to a surface. 3. A flexible backing member for a windshield wiper blade adapted to wipe curved windshields, said backing member being relatively ilexible in a plane substantially normal to the windshield and relatively inflexible in a plane transverse thereto, said backing member having at l0. ln a windshield wiper blade the combination of a resilient elongate wiping element having a wiping portion and a back portion spaced from said wiping portion, a flexible elongate backing member engaging with said back portion of said lwiping element for coaction therewith, said backing member being ñexible in a plane substan least two longitudinal portions, one ot said portions hav ing a greater effective length than its over-all length and being thinner constant throughout its length in the verti cal dimension than at least one of said other portions whereby to produce a greater degree of ilexibility in said tially normal to the windshield and relatively iniiexible in one portion than in the other. 4. A flexible backing member for supporting the wiping element of a windshield wiper blade for curved wind a plane transverse thereto, said backing member having at least one longitudinal portion corrugated transversely shields, said backing member being relatively Ilexible in a plane substantially normal to the windshield and relatively thereto, whereby to cause a difference in the inherent re sistance to ilexure of said longitudinal portion of the ilexi le member to accommodate differing degrees of curva inilexible in a plane transverse thereto, said backing niem ber being manufactured from a material of a thickness ture of different areas of the surface of a windshield to be wiped, and pressure-distributing structure applying pressure to said backing member at longitudinally spaced required to provide the minimum of flexibility desirable for at least one longitudinal portion of said backing men - apart portions thereof to distribute pressure of a wind ber, another longitudinal portion of said backing mem ber being given additional etîective length and less thick 30 shield wiper arm to the blade, said corrugations being of ness by reversely corrugating said portion whereby to pro continuous sinusoidal shape. ll. ln a wiper assembly comprising a pressure-dis tributing device operatively connected with a wiping blade comprising resilient elongate ílexor means having end por 5. ln a wiper blade for curved windshields, a resilient rubberlilre elongate wiping element, a resiliently and re 35 tions and an intermediate portion adapted to cooperate versely flexible elongate pressure-transmitting backing with said blade, said ilexor means being relatively flexible vide less resistance to llexure in said last-named portion than in said first-named portion. strip associated coactively therewith, said backing strip in a plane substantially normal to the windshield and be being relatively flexible in a plane substantially normal to ing relatively inflexible in a plane transverse thereto, the windshield and relatively inilexible in a plane trans transverse sinusoidal oorrugations formed in at least one 40 verse thereto, said backing strip being fabricated from end portion thereof, said end portions of the iiexor means material of substantially uniform thickness and having a being operatively connected at spaced points to said pres plurality of readily flexible portions substantially equal sure-distributing device to receive pressure therefrom. in width, at least one oí said portions having transverse l2. A windshield wiper assembly comprising a pressure sinusoidal corrugations whereby to produce a greater de transi-.itting member operatively connected with a wiper blade, said wiper blade having a resilient elongate wiping gree of flexibility therein. 6. ln a wiper blade for curved windshields, a resilient element with a wiping portion and a back portion, ilexible rubberlike elongate wiping element, a resiliently rlexible elongate backing means for said wiping element for co elongate pressure-transmitting backing strip associated co action therewith, said backing means being relatively ilexi actively therewith, said backing strip being relatively ilexi ble in a plane substantially normal to a windshield to be ble in a plane substantially normal to the windshield and relatively inñexible in a plane transverse thereto, said wiped. and being relatively inflexible in a plane transverse thereto, transverse corrugations formed in at least one end portion of said backing means, said transverse corruga tions comprising a plurality ot adjacent curved means formed out ot the pla. e or” said backing member along backing strip having a plurality of adjacent readily flexible portions substantially equal in width, at least one of said portions having transverse continuous sinusoidal shaped corrugations whereby to produce a greater degree of 55 aries lying substantially perpendicular to the longitudinal axis of said backing means whereby said one end portion ilexibility therein. 7. ln a wiper blade for curved windshields, a resilient rubberlilte elongate wiping element, a resi .ently and re versely ñexible pressure-transmitting bac ring strip associ ated coactively therewith, said backing strip being rela tively ñexible in a plane substantially normal to the wind shield and relatively iniiexible in a plane transverse there to,'said backing strip having a plurality of longitudinal portions, at least one of said portions having eorrugations transversely disposed relative to the longitudinal axis of said blade whereby to produce in said last-named portion a diiierent inherent resistance to flexure, said corrugations defined by adjacent continuous curved sections. 8. In a wiper blade for curved aviiidshields, a resilient rubberlike elongate wi -ng element, a resiliently ilexible backing strip associated coactively therewith, said backing strip being iiexible in a plane substanL ally normal to the windshield and being inflexible in a plane transverse thereto, said backing strip having a plurality of longi tudinal portions, a plurality of transverse corrugations of the backing means is more freely llexible than the rest oí the backing means in said plane substantially normal to the windshield. 60 i3. A windshield wiper assembly comprising a pressure transmitting member operatively connected with a wiper blade, said wiper blade having a resilient elongate wiping element with a wiping portion and a back portion, flexible elongate backing means for said wiping element for co action therewith, said backing means being relatively ilexi ble in a plane substantially normal to a windshield to be wiped. and being elatively inflexible in a plane transverse thereto, transverse corrugations formed in at least one end portieri of said backing means, said corrugations com prising a plurality of undulations extending above and below the plane ot said backing me. .ber, said corruga tions each having an axis lying substantially perpendicular to the longitudinal axis of said backing means whereby said one end portion of the backing means is more freely 3,076,993 ñexîbîe than the rast of the backing means in said plane Su‘osîanîîaìly normal is the Windshield. 2,782,445y 2,314,521 2,871,495 FOREEGN PATENTS UNlTED STATES 1% TENTS ,589,3 2,6GS,2 5 2,664,535 2,772,436 Caïson ______________ __ Mar. 18, Ecl-¿m51 ______________ __ Aug. 26, Qísïîei ________________ __ 5, Deíbel __'______________ __ Dec. 4, Krohm ______________ __ Feb. 26, 1957 ‘Wallis ________________ __ Dec. 3, 1957 Oishei et a1. ___________ __ Feb. 3, 1959 1952 1952 1954 1956 10 744,398 '785,865 Great Britain __________ __ Feb. 8, 1956 Great Briîain __________ __ Nov. 6, 1957 OTHER REFERENCES Germany, 517,814 11/63C, Dec. 2Q“, 1956.