DE2223534A1 - Mold for shaping the tread of a pneumatic tire and a method for producing such a mold and pneumatic tires produced therewith - Google Patents

Description

DR. MÜLLER-BORG DIPL.-PHYS. DR. MANITZ DIPL.-CHEM. DR. DEUFEL DIPL.-ING. FINSTERWALD DIPL.-ING. GRÄMKOW 2223534 PATENT LAWYERS

- D 1333 J * MAY «72

Dunlop Limited
London, England

IPorm for shaping the tread of a pneumatic tire as well as Method for producing such a shape and thus

manufactured pneumatic tire

The invention relates to a mold, in particular a mold which is used for molding the tread of a pneumatic tire with a matrix is provided.

The tread of a pneumatic tire usually has a Patterns of grooves and / or sole seats to the water drainage capacity of the tire and thus its traction to improve. Multiple slots are provided in the tread of a pneumatic tire, on one or both of them Ends are completely enclosed by rubber, and under Load conditions, these narrow sole seats are points of application for the load and often the starting point of Cracks in the tread.

According to the invention, a mold for forming the tread of a pneumatic tire comprises a matrix of knife blades

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for forming sole seats in the tread, the free ends of these MesaerJjlätter each from a sleeve are included that have a curved external cross-sectional profile and wherein the free ends of the knife blades are effectively enlarged.

According to the invention further comprises a method of manufacture the shape described in the preceding paragraph, the provision of a slot and a hole in the tread mold surface the shape and anchoring of a knife blade in the slot and a sleeve in the hole, the slot leading into the hole so that when the knife blade and the sleeve is anchored therein, the sleeve having a curved outer cross-sectional profile surrounds the end of the knife blade and effectively enlarges the end of the same.

The invention further comprises a pneumatic tire, the tread of which is formed in a shape as described above.

The tread molding matrix preferably has ribs to the Forms of grooves in the tire tread. An end to some or all of the knife blades may be anchored in such a rib; the opposite ends of the knife blades, these are their free ends, are then enlarged by the sleeves

They knife blades and the sleeves are generally made of Metal (soles. Metal alloys), and di · metal sleeves

For the sake of simplicity, roller pens (vulst pens, roller pens) be.

The end of the sleeve that is not anchored in the mold surface can preferably also be closed, for example duroh Pressing to prevent rubber from penetrating into this during to prevent the formation of a tread.

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The knife blade and the sleeve can be used separately from one another in the slot and the hole for anchoring there but are preferably assembled prior to insertion into the sole seat and hole.

The invention obviates any need for the soleplate and / or filling the knife blades and sleeves; Steps that are required, for example, if the aim is to achieve the to achieve the same result by rolling the ends of the knife blades

The knife blade and sleeve assembly according to the invention is created In the molded tire tread a so-called sole seat, the end of which is enlarged by a small round looh so that the stress concentration at the end of the slot is reduced and the tread tearing at the end of the slots is essentially eliminated

The invention is described below by way of example with reference to the drawing; in this shows

Pig 1 a cross section through a tread molding surface, in which a knife blade according to the invention is attached;

Pig * 2 is a plan view of a knife blade with the same at each free end according to the invention attached sleeves; and

Pig 3 is a perspective view of a sleeve according to the invention.

Like in Pig. 1 are in the tread pattern a form 1 a sea blade 2 and roller pins 3 and 3 and 4 (see Pig · 3), the latter enclosing the ends 5 and 6 of the knife blade (see Pig. 2)

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and effectively increase the radius thereof so that the ends of the subsequently formed by the knife blade Slot can be enlarged to a softly rounded profile.

As can be seen from the broken lines in I * ig · 1 the knife blade 2 is anchored in a slot 7 in the mold 1, which slot in the holes 8 and 9 leads, in which the roller pins 3 and 4 are anchored.

-Patent claims-

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Claims (8)

Claims 1.) Mold for forming the tread of a pneumatic tire with knife blades for forming sole seats in the tread containing matrix, characterized in that the free ends of the knife blades in a sleeve with a curved outer transverse profile are included, with the free ends of the knife blades are effectively enlarged. 2. Mold according to claim 1 with ribs provided on the matrix for forming hats in the tire tread, characterized in that at least some of the knife blades are anchored at one end in one of the ribs and the free ends of the knife blades are enlarged by a sleeve 3. Form according to one of claims 1 or 2, wherein the knife blades and the sleeves are made of metal or metal alloys, characterized in that the metal or metal alloy sleeves roller pins include. 4. Form according to one of claims 1 to 3, characterized in that the end not anchored in the form the sleeve is closed, thus preventing the ingress of rubber during the formation of the tire tread is essentially prevented. 5. A method for making a mold according to claim 1, characterized in that a slot and a hole provided in the tread mold surface of the mold and a knife blade in the slot and a sleeve in the Hole, with the slot in the looh 209849/0791 leads and, if the knife blade and 'the sleeve in it are anchored, the sleeve with a curved outer transverse profile comprises the end of the knife blade and effectively enlarges the end thereof. 6. The method of claim 5 including the step of providing ribs on the tread-forming matrix for Forming grooves in the tire tread, characterized in that that one end of at least some knife blades is anchored in a rib and at the free end a sleeve is provided for each sheet. 7. Method according to one of claims 5 or 6, characterized in that that the knife blade and the sleeve are inserted separately into the slot or the hole and anchored therein will. 8. The method according to any one of claims 5 or 6, characterized in, that the knife blade and the sleeve assembled prior to insertion into the slot and hole will. 209849/0791