Mold with a device for molding a keyhole sipe in a tire tread

摘要

The present invention provides for an improved device for molding keyhole sipes larger in size, i . e . sipes having a wider passage, than currently being formed in treads that will avoid damaging the tread during formation and removal thereof from a mold. The device (10) includes an elongated deformable body member (16) having a blade (18) extending in a direction away therefrom and substantially along the length thereof. The body member also includes a stiffening member (32) securely fixed in position therein that extends substantially the length thereof. The stiffening member provides a desired rigidity to the deformable body member, thereby limiting flexion along its length under the stress of a rubber formulation when the mold is closed during the molding process. Also, the deformable body member provides low stress on the tread when a slit of the keyhole sipe is pulled around the body member during removal of the tread from a mold.