United States, Patent
`3,910,332
`[11]
`
`Felker
`‘
`[45] Oct. 7, 1975
`
`[191
`
`[54] ART OF FORMING TIRE TREADS WITH
`ELONGATED TRACTION-AUGMENTING
`ELEMENTS
`1
`Inventor: Paul J. Felker, Marshfield, Wis.
`
`[75]
`
`2,568,542
`3:22:33
`,
`,
`3,182,706
`3,276,501
`3,283,053
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`Freistedt ............................. 152/211
`9/1951
`fin}? ----------- iii/iii
`3/1322
`e1 er....
`.....
`Cousins....
`..... 152/211
`5/1965
`10/1966 Clark ............ 152/211
`11/1966
`Felker ................................. 152/211
`
`
`
`[73] Assignee: Penetred Corporation, Marshfield,
`W‘S'
`Feb. 14, 1974
`
`Filed:
`
`[22]
`
`[21] Appl. No.2 442,526
`
`Related US. Application Data
`[62] Division of Ser. No. 20,356, March 17, 1970, Pat.
`
`,
`NO- 33872207'
`152”“. 152/168' 152/169‘
`[52] U S Cl
`’
`’ 152/222’
`' """""""""
`-
`-
`Int. C1.2 ....................................... B60C 11/16
`[51]
`[58] Field of Search ........ 152/208, 209 R, 210, 211,
`152/168, 169, 222
`
`[56]
`
`2,502,521
`2,565,619
`
`References Cited
`UNITED STATES PATENTS
`4/1950 Hawkinson ......................... 152/211
`8/1951
`Oest .................................... 152/211
`
`Primary Examiner——Drayton E. Hoffman
`Attorney, Agent, or Firm—Arthur L. Morsell, Jr.
`
`[5 7 ]
`
`ABSTRACT
`
`A vehicle tire has a rubber tread portion with lateral-
`ly-spaced,
`circumferentially-extending rider
`strips,
`each rider strip being zigzag in plan view so that the
`sides of the rider strips present alternating peaks and
`valleys. A helical wire coil extends circumferentially
`0f the me i" eaCh rider Strip’ With the peaks on the
`sides of the rider strips providing rubber stock which
`projects beyond the sides of the wire coils to retain the
`latter in position during use. This rubber stock is in
`the form of a series of triangular blocks and there is a
`sipe slit extending transversely into each of said triang-
`ular blocks from the peak thereof.
`.
`.
`'
`1 Claim, 5 Drawmg Figures
`
`
`
`Dynacraft V. Mattel
`IPR2018-00042
`
`Dynacraft BSC, Inc.
`
`Exhibit 1007
`
`

`

`U.S. Patent
`
`Oct. 7,1975
`
`3,910,332
`
`
`
`

`

`1
`ART OF FORMING TIRE TREADS WITH
`ELONGATED TRACTION-AUGIVIENTING
`ELEMENTS
`
`This application is a division of my co—pending appli-
`cation Ser. No. 20,356, filed Mar. 17, 1970, now U.S.
`Pat. No. 3,872,207, and reference is also made to my
`U.S. Pat. No. 3,687,583, which was also a division of
`said application Ser. No. 20,356.
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention pertains to retreated tires or to
`new tires wherein the tread portion has elongated,
`circumferentially-extending rider strips with traction-
`augmenting members, such as wire coils, in the rider
`strips.
`.
`2. Description of the Prior Art
`It has heretofore been proposed to retread tires or to
`manufacture new tires with wire coils embedded in the
`rubber of the rider strips. The proper positioning of the
`coils during tread molding has always presented prob-
`lems. Heretofore it has been customary to cut a length
`of wire coil approximately two inches longer than the
`circumference of the tire and to insert byrhand one of
`these coils in each of the grooves of the matrix with
`ends abutting. With this arrangement the wire coils are
`longitudinally compressed because of their greater
`length and they thereby maintain themselves in the
`grooves of the matrix. With this early method of proce-
`dure, centering of the coils in the grooves presented a
`problem, but in Crooker U.S. Pat. No. 2,619,678 this
`problem was dealt with by having a centering channel
`in the bottom of each of the matrix grooves. In my prior
`U.S. Pat. No. 3,283,053, circumferential extents of
`sipe-forming strips were uSed in wide grooves of the
`matrix for centering wire coils in the grooves. In Spitz
`U.S. Pat. No. 2,832,292, a method is shown which in—
`volves the use of.peculiarly-shaped wire coils having
`projecting wings for centering the coils in the grooves.
`It is desirable to provide a simpler method which can
`be used with standard coils and which does not require
`the use of the centering channel in the bottom of the
`groove as in the Crooker patent, and which can employ
`a simpler type of siping than that required by my U.S.
`Pat. No. 3,283,053.
`
`SUMMARY OF THE INVENTION
`
`The present invention provides a vehicle tire which
`has a rubber
`tread portion with laterally-spaced,
`circumferentially—extending rider strips, each rider
`strip being zigzag in plan view so that the sides of the
`,rider strips present alternating peaks and valleys, there
`being an elongated traction-augmenting member such
`as a helical wire coil extending 'circumferentially of the
`tire in at least some of the rider strips, with the peaks
`on the sides of the rider strips providing rubber stock
`which projects beyond the sides of the wire coils.
`A further object of the invention is to provide an im-
`proved tire having traction-augmenting members'in the
`rider strips thereof, wherein each rider strip has a row
`of triangular blocks of rubber on each side projecting
`‘ beyond the sides of the coil, to thereby create ample
`stock to maintain the coils in the rider strips during use.
`A further object of the invention is to provide an im-
`proved tire as above described wherein, in a preferred
`V embodiment, there is a sipe slit extending transversely
`
`3,910,332
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`2
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`inwardly from the peak of each of said triangular
`blocks.
`
`With the above and other objects in view, the inven-
`tion consists of the improvements in the art of forming
`tire treads with elongated traction-augmenting ele-
`ments, and all of its parts, combinations, and steps, as
`set forth in the claims, and all equivalents thereof.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the accompanying drawings, illustrating one com-
`plete embodiment of the preferred form of the inven-
`tion, in which the same reference numerals designate
`the same parts in all of the views:
`FIG. 1 is a fragmentary view looking at the interior
`of a tread-forming matrix showing wire coils inserted in
`two of the grooves of the matrix;
`FIG. 2 is a fragmentary perspective view showing a
`portion of the matrix interior with one coil centered in
`a groove;
`
`FIG. 3 is a fragmentary view of a tire tread showing
`several of the rider strips with wire coils therein;
`FIG. 4 is a diagrammatic plan view of a matrix
`groove; and
`FIG. 5 is a fragmentary cross section through one of
`the matrix grooves showing a coil therein.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Referring now more particularly to FIG. 1 of the
`drawings, the improved matrix may be used either for
`retreading operations or for the manufacture of new
`tires. It includes complementary circular matrix sec-
`tions 20 and 21 which meet at a circumferential parting
`line 22. These matrix sections are designed for use in
`a mold in the manner shown in FIGS.
`1 and 2 of
`
`Crooker U.S. Pat. No. 2,619,678, the operation of
`which is fully described in said patent. In this prior pa—
`tent the centering channels in the bottoms of the rider
`strip-forming grooves maintain the coils in a laterally-
`centered position in the grooves of the matrix during
`the curing operation and prevent the coils from bowing
`from one side to the other of the grooves. Such bowing
`would be unacceptable -in practice as the sides of the
`coil are then not protected by enough rubber in the fin-
`ished product and the coils may work loose in use.
`The matrix sections have circumferentially-extending
`ribs 23 and 24 on each half, and each half has a longitu—
`dinal half 25 of a center rib, one on each side of the
`parting line 22. The spaces between the ribs 23 and 24
`provide rider strip-forming grooves 26 and 27 which
`form the rider strips 126 and 127 on the finished tire,
`as shown in FIG. 3. Any selected number of ribs 23—24
`may be provided in the matrix depending upon the
`number of rider strips desired on the tire. In the ar-
`rangement embodied in FIG. 1 there are four rider
`strip-forming grooves.
`As a novel feature of the present invention each of
`the matrix ribs is shaped in a special manner to provide
`centering for the wire coils 28 or other elongated trac-
`tion-augmenting elements while still providing stock at
`the sides of the coils to furnish protection so that the
`coils will not work loose in use. To accomplish this pur-
`pose the matrix ribs 23, 24 and 25 are zigzag in plan
`view and have sides with alternating peaks 30 and val-
`leys 29. The valleys 29 of the rib 23 on one side of a coil
`are opposite peaks 30 of the rib 24 on the other side of
`the Coil 28, referring to the left-hand coil in FIG. 1.
`
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`3,910,332
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`An additional feature of the novel method which is
`not essential in practice but which is very desirable in
`the final product is to equip the matrix with relatively
`short metal sipe-forming strips 31, with one strip pro-
`5 jecting laterally from the bottom of each valley 29, as
`shown in FIGS. 1 and 2. Each strip 31 has a transverse
`length which is limited so that it projects as at (p) in
`FIG. 5 approximately the same distance as the adjacent
`peaks 30. In the case of a standard passenger car tire,
`this is preferably at least 1/s inch. These strips, being
`short, do not interfere with the groove width (W) of
`FIG. 1 so that the coils may be readily inserted without
`interference from the sipe strips. In addition, the ends
`of the sipe strips will frequently contact portions of the
`wire coils due to the varying pitch sequence between
`the matrix and the coil, as may be seen in FIGS. 1 and
`2, to further aid in centering the latter.
`With coils in all of the grooves 26—27 of the matrix,
`when the procedure is used for retreading, the curing
`bag or curing tube of the mold is inflated and this infla-
`tion pressure forces the uncured rubber of the tread
`stock against the hot matrix, the uncured rubber being
`forced into the pattern of the matrix. After a predeter—
`mined period of exposure to the heat and pressure, the
`curing of the rubber is completed and the tire is re-
`moved from the matrix. When the mold is in closing
`condition the ribs 23, 24 and 25 of the matrix enter the
`tread stock and the rubber of the tread stock is forced
`to flow into the grooves 26 and 27 to fill the grooves
`and cure around the wire coils 28, as is shown in FIG.
`3. A very similar procedure may be used in the building
`of new tires.
`
`Referring to FIG. 4, the circumferential distance (L)
`between peaks is relatively short and, in a preferred ar-
`rangement, % inch or less for a passenger car tire. The
`unobstructed channel portion within each of the -
`grooves 26 or 27 has a width (W) which is of between
`5/16 and 7/16 inch for a passenger car tire to receive
`traction-augmenting members which are of no greater
`width, the standard coil for a passenger car tire having
`a diameter of 3/8 inch, with the coil having approxi-
`mately four turns to the inch. The depth (d) of each
`valley is preferably at least 1/9 inch for a standard pas-
`senger car tire. While the wire is preferably flexible,
`nevertheless, due to the short distance (L) betWeen
`peaks, the wire is of such property that it is unable to
`flex sidewise into the valleys 29 of the ribs after the
`coils are inserted to the position shown in FIG. 1, the
`coils preferably having a greater number of pitch dis—
`tances (x) FIG. 1, per unit of length than the number
`of matrix peaks per unit of length so that the pitch se-
`quence of the coil is out of sequence with the peaks of
`the matrix. Thus the coil will not straddle a series of
`
`peaks and will have positive centering between peaks
`on alternating sides of the matrix groove. With this ar-
`rangement lengths of wire coil approximately 1 inch
`longer than the circumference of the tire, for passenger
`car tires, may be inserted in each of the grooves 26 and
`27 in the manner shown in FIG. 1 with the ends of the
`coil abutting. With this arrangement the coils are longi-
`tudinally compressed somewhat and tend to maintain
`themselves seated in the grooves of the matrix. With
`the novel method of the present invention, and with the
`use of the novel matrix, each coil 28 is automatically
`centered in its groove, as shown in FIG. 1. With the
`present invention,
`in the manufacture of the matrix
`ribs, a constant pitch (distance between peaks 30) can
`be employed as this is the simplest procedure in manu-
`facture, and in manufacture of the wire coils there is no
`need to worry about maintaining any special tolerances
`or consistency in the pitch of the convolutions. As a
`matter of fact, the poorer the coil is in this respect, the
`better the centering in the mold.
`As a typical example for a passenger car tire it may
`be assumed that (W) in FIG. 4 is % inch, (L) is % inch,
`and that the coil has approximately 48 turns to the foot,
`this, of course, varying somewhat due to tolerances and
`inconsistencies in manufacture. With this general rela—
`tionship, if the pitch distances of the coil, in an axial di-
`rection as at (d) FIG. 1, were perfectly constant, which
`they are not, the coil would contact a peak as at (C) on
`the left-hand side of FIG. 4, and would then have an-
`other contact no farther away than (C) on the right-
`hand side of FIG. 4. If all of the pitch distances were
`constant there would be contact every 1 1%; inches. How-
`, ever, because there will be imperfections and inconsis—
`tencies in manufacture in both the matrix and the coils,
`this contact may vary somewhat around the circumfer-
`ence of the tire, it being noted that the peaks 30 extend
`at right angles to the bottom of the grooves 27 whereas
`the sides of the coils have angularly-extending portions
`which cross the peaks at about a 30° angle so that there
`will always be sufficiently frequent contact between the
`coil and some of the peaks 30 to provide positive cen—
`tering of the relatively stiff wire coil. Furthermore,
`where the sipe strips are employed, their end edge ex—
`tend parallel to the peaks 30 and will be crossed at
`about a 30° angle by portions of the coil convolutions
`so that the sipe strips also aid in positive centering.
`
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`In FIG. 3, showing the novel tire tread, the numeral
`32 designates the tread stock having zigzag ribs 33
`thereon, each rib having a centered coil 28 therein. It
`is to be noted that on each side of each coil there is a
`circumferential series of. triangular rubber blocks 34
`which project beyond the sides of the coils to provide
`sufficient stock for protection of the coils so they do
`not work loose in use. Where the sipe-forming strips 31
`are employed in the matrix there will be sipe slits 35 ex-
`tending inwardly from the peak of each triangular
`block 34. These slits break up the solid rubber portions
`of the rider strips and bring about a desired flexibility
`of action during use. Besides centering the coils, the
`novel method and matrix create rider strips on the tire
`which improve traction due to the zigzag configuration.
`While this invention is particularly adapted for use in
`connection with wire coils, it is obvious that it is appli-
`cable for use in connection with various other types of
`elongated traction-augmenting elements which require
`centering, a number of which are illustrated and de-
`scribed in my U.S. Pat. No. 3,283,053.
`It is to be understood that I do not desire to be limited
`to the exact details of construction shown and de-
`scribed, for obvious modifications will occur to a per
`son skilled in the art.
`What I claim is:
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`1. In a tire having a rubber tread portion with later—
`aly-spaced, circumferentially-extending rider strips,
`each rider strip being zigzag in plan view so that the
`. sides of the rider strips present alternating peaks and
`valleys, the bottoms of the valleys on one side being
`spaced from the bottoms of the valleys on the other
`side of a rider strip to provide unbroken stock of sub-
`stantial width, and an elongated traction-augmenting
`member positioned in said unbroken stock in at least
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`3,910,332
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`some of said rider strips, the peaks on the sides of the
`rider strips providing rubber stock projecting beyond
`the sides of the traction—augmenting members to retain
`the latter in position during use, which rubber stock is
`in the form of a series of triangular blocks, the width of 5
`the traction-augmenting members being substantially
`equal to the transverse distaance between the bottoms
`
`of the valleys on one side of the rider strip and the bot-
`toms of the valleys on the other side of the rider strip,
`there being a sipe slit extending transversely into each
`of said triangular blocks from the peak thereof, the
`length of each sipe slit being substantially equal to the
`altitude of each triangular block.
`*
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