Патент USA US2121955код для вставки
'June2s,.193s. E565‘; PNEUMATIC TIRE TREAD ' Filed June 15, 1956 ' 4 2,121,955 ‘ I ' Patented June 28, 1938 UNITEb’IS-TATES PATENT OFFICE ' ensues Ernst EgerrGrosse’l'ointe mm ms'raasn Michsarslgnor " ‘ to United States Rubberv Products,’ Inc.I New ' York, N. 1., a corporation of Delaware Application June 18.1838, Serial No. we ' s can». (oi. use-zoo). ' tread is particularly improved after. ‘subjection This invention relates to pneumatic tires, and to the present method'of tread treatment. Experiments have indicated that the width of v , and to the structural formation of the antiskid 1 formation to increasethe eiliciency of such tires . the ribs should not'be less than ‘3 ‘percent of the ' I in operation. ‘ Inv general, the invention refers normal width of vthe tire in crosssection, and s to a pneumatic tire having a tread comprising a that the maximum'wldth' of the‘ rib " should not plurality of relatively narrow. circumferential exceed 8 percent of ' the normal width of the tire ‘ribs divided circumferentially by a pluralltycf in cross section. . In other words, the dimension transverse incisions such as slits or narrow slots x as shown in' Fig. lshould be‘equai to from 3 10’ ’ '1. having their bases terminating in openings which to 8 percent of the dimensional character Y. Subsequent to the vulcanization of the tire, the I extend parallel with the slits. ' I . In tires having treads with transverse slits or tire tread is subjected to a vslitting operation for narrow slots for improving skid qualities there producing narrow cuts or incisions 'l in the tread in particular it relates to pneumatic tire treads transversely of the ribs. The bases of these slits - 7 I " is a tendency for the bases to continue to extend l6 deeper in the form of cracks. To overcome this conditionit has been the practice to slit the tire to a relatively shallow depth, less, than the depth of the tread rubber, and to space the slits a sub stantial distance apart. Y ' terminate ‘insmall apertures 8 which extend 15 parallel with the slits. Fig. 2 illustrates a side view of the tire i and shows the proportionate size of the apertures 8. The vrib formation t is de?ned by a plurality of grooves 9, having 20 bases Ill. 1 ‘ ' An object of my invention is to prevent crack ing of slit or slotted tread tires; another object 1 As shown in Fig. 2, the apertures 8 are posi tioned slightly above the bases ll of the grooves is to permit the tread‘to be slit to a depth sub stantially equal to the‘ wearing portion of they so that the apertures 8 which lie between the ' tread; and a further object is to permit the slits grooves s will be free from the curvatures at ' ll to be spaced a less distance apart. As a result the bases it. While the apertures 8 are shown 35 of these objects a tire of improved antiskid and in the form of circular openings, it is to be un derstood that they may be of various shapes wearing qualities is obtained. , ‘ ' These and other objects and advantages will appear more fully in‘the following detailed de 80 scription -when considered in connection with ‘ the accompanying drawing, in which:-,- _ such as that indicated in Fig. 3, wherein a tire I ii is provided with apertures I! in the form ' ~ 0! triangular-‘openings which communicate with 3° slits ll. Any form of opening at the bases of . Fig. 1 is a transverse view, in section and in - the‘ slits‘is su?lcient to accomplish the advan perspective, of a portion of a pneumatic, tire tages of the present invention, provided the bases embodying my invention; ‘ of the apertures are ?at or substantially ?at, or vcurved as in the lower portion of a circular ap-v 35 erture, as such shapes being free from sharp “BEE-‘tend to prevent crack propagation toward , ‘- ll ' Fig. 2'is aside elevational view of a portion of the tire shown‘ in Fig. 1; and > Fig. 3 is a similar view illustrating a modified form. of the invention. ' the carcass 2.‘ , Referring to the drawing, and in particular to 40 Fig. 1, I showapneumatic tire I having a car ' case I of strain resisting'elements, inextensibie ' bead elements 3 and l. and a wear resistant tread , I of rubber composition. - ' In formation the tread 5 isillustratedin the 45 form of a plurality of "circumferentially extend' Iin‘g ribs tin-While the features of ‘my invention ~ The size of the apertures disposed at the base“ I of 10118theasslits they is not do' of notparticular materially importanc impair ' c" . - v strength of the ribs. , I'?nd, however; that god it ' results are obtained from a tire having " apér-f tures which measure from about 1/54 inch to ‘1/8 45 inch in general diameter. The size of the aper- . ture is somewhat determined by the method are applicable to treads having designs of vari used to provide such apertures in ‘the tread. ous. con?gurations, I prefer its application to a For example, a hot wire may be forced into the “ .tread design of plain, circumferential rlbs.- ‘It , slit of . the tread and permitted to lodge at the 56 .- ‘so h'asbeen demonstrated that a tread comprising base of the slit for a short period. In such case circumferential ribs of a width within deilnite the resulting aperturel will be relatively small. ‘limitations shows a substantial improvement in The apertures may also be produced by a knife antiskid qualities,‘ particularly on wet road sur 3 faces. ' It is well known that a tread of rib for as mation is relatively quiet in operation.- Such a having the combined shape of the-“slit and the opening at the base of the slit. In such case a I 2 2,121,955 the slit and the aperture may be cut into the tread in the same operation. It 'is also possible to produce the transverse apertures in the tread by providing removable pins in the mold, and forming the apertures in the rubber during vulcanization of v the tire. m such case the tire would be subsequently slit in such manner that the cuts would extend into the previously formed apertures. While I prefer to make slits in the limited openings extending relatively transversely of the ribs and located between the outer free face of each rib and its base, and an incision extend ing from each of said openings outwardly vto the outer free face of the rib in‘which the opening is provided. 4. A pneumatic tire ‘comprising a carcass of. strain resisting elements and a tread of rubber composition de?ning antiskid elements which are interrupted by spaced incisions of a widthsuch 10 sense of the. word, that is by making. incisions ' that when under load their side walls engage for without the removal of substantiallyany of the appreciable distances for mutual support and tread rubber; yet the invention is- applicable to terminating in enlarged openings for the pre- ' narrow slots or incisions whose side walls are vention of crack propagation into the underlying 15 normally out of engagement, such as would be rubber composition. . I. produced by a saw cut, but which engage for 5. A pneumatic tire comprising a carcass of 15 cooperative support when a load‘l's applied, and strain resisting elements and a tread of rubber such slots are included in the term “incisions" as composition de?ning antiskid elements which are 1 herein used. , . interrupted by spaced slits whose walls are sub- ' While I have shown the slits and communicat stantially parallel and normally in engagement ing apertures extending transversely of all of 7 for a considerable distance and which terminate 20 the circurnferentially extending ribs, it is to be well within the tread rubber composition in en understood that the slits and their accompany larged openings for the prevention of crack prop ing‘ base apertures may extend in a wide variety agation into the underlying rubber composition. of patterns, such as diagonally of the circumfer 6. A pneumatic tire comprising a carcass of ential ribs, or they may extend only into certain strain resisting elements and a tread of rubber 25 of the ribs or combinations thereof, depending composition de?ning circumferential, functionally upon the particular slit formation desired. continuous ribs and intervening grooves, said ribs While I have shown and described certain pre having spaced ‘incisions of a width such that 80 l0 . ferred embodiments of my invention, it will be understood that modifications may be made therein without departing from the spirit of the invention or the scope of the appended claims. Having thus described my invention, what I 35 claim and desire to protect by Letters Patent is:— 1. A pneumatic tire having a carcass of strain resisting elements and an outlying tread of vul canized and wear resistant rubber composition, said tread having an antiskid con?guration and being provided with a plurality of relatively small openings extending more transversely than cir cumferentially located between the ground-con tacting surface of the' tread and the underlying carcass, said tread being provided with slits ex 45 tending from said openings outward to the ground contacting surface of the tread,,the'walls de?n ing said slits being substantially parallel and spaced apart a substantially less distance than the width of said openings. . . 2. A pneumatic tire having acarcass of'strain resisting elements and an outlying tread of vul canized and wear resistant rubber composition, said tread ‘being provided with anantiskid con ?guration de?ned by grooves -molded into the 55 tread, and said tread being provided with a" multiplicity of small openings extending more transversely than circumferentially located be-i tween the ground contacting surface. of the tread and the bottoms of said grooves,‘said tread being provided with incisions substantially narrower than said openings and extendin'g'from said open when under load their side walls engage for ap preciable distances for mutual support and ter minating in enlarged openings for the ‘prevention of crack propagation into the underlying'rubber composition. ‘‘ ‘7-. A pneumatic tire comprising a carcass of ' strain resisting elements and a tread of rubber composition de?ning circumferential, function ally continuous ribs and intervening grooves, said ribs having spaced slits whose walls are substan tially parallel and normally in engagement for 40 a considerable distance and which terminate well within the tread rubber composition in enlarged openings for the prevention of crack propagation into the underlying rubber composition. 8. A pneumatic tire comprising a carcass of strain resisting elements and a tread of rubber 'ally continuous ribs of a width of the order of from 3 to 8 percent of the maximum width of i the tire and intervening grooves, said ribs having 50 spaced incisions of a width such that when under load their side walls engage for appreciabledis+ tances for mutual‘ support and terminating in enlarged openings for ‘the prevention of crack propagation into the underlying rubber compo 55 sition.' ' - -~ . -9. A pneumatic tire comprising a carcass of strain resisting elements and a tread of rubber composition de?ning circumferential, function ally continuous ribs of a width of the order of -from_ '3' to 8 percent of the maximum width of ings' to the ground contacti-ngsurface ‘of the, the tireand' intervening grooves, said ribs having tread. _ . . > . _ 3. A pneumatic tire having a carcass'of ‘strain elements and an outlying" tread of vul as. resisting caniz‘ed and wear resistant rubber. composition; " said tread’ being providedwith a plurality of cir-' ’ vcumt'erentially extending ribs, each of‘ said ribs beingprovided with a plurality of relatively small 45 composition de?ning circumferential, function spaced slits whose walls are substantially parallel and normallyin engagement for a considerable distance and which terminate well within the tread rubber composition in enlarged openings forthe prevention of crack propagation into the . underlying rubber composition. v ERNST EGER.