Tire mold milling machine

A mechanism for engraving the surface of an article wherein the surface is curved in more than one direction about different radii of curvature comprising:

• article support means including rotatable means for rotating said article about a first axis of rotation at a predetermined velocity, and linear reciprocating means for reciprocating said article in a plane perpendicular to said first axis of rotation;
• tool support means for supporting an engraving tool for rotation about a second axis of rotation, said second axis of rotation extending along the center line of said tool on a radius intersecting said first axis of rotation;
• and
• control means supporting said tool support means for oscillation of said tool support means about a third axis of rotation perpendicular to said first and second axes of rotation, said control means including advancing means for advancing said tool support means to vary the radius of curvature of said engraving tool about said third axis of rotation so as to correspond to the radius of curvature of the surface to be engraved, and said control means including tracing means for tracing a pattern to be engraved on the surface, a slider crank mechanism and a parallelogram linkage interconnecting said slider crank mechanism and said tool support means, means for transmitting drive signals to said slider crank mechanism, and said parallelogram linkage being responsive to signals applied to said slider crank mechanism to cause said tool support means to describe an arcuate path of movement about said third axis of rotation, and means correlating the rate of rotation of said article support means about the first axis of rotation with the rotation of said engraving tool about the third axis of rotation in response to tracing of the pattern to be engraved.

In a tire mold milling machine wherein a mold blank is provided with an inner surface of generally toroidal configuration and is mounted for rotation on a horizontal table, and pattern tracing means are provided for tracing a pattern to be formed on the inner toroidal surface of said mold by means of a cutting tool mounted for rotation about a longitudinal axis through said cutting tool, the combination therewith comprising:

• an overhead tool support mechanism adapted to suspend said cutting tool in confronting relation to each surface portion to be engraved having a vertically adjustable frame including a pair of inner vertical frame members disposed in horizontally spaced relation to one another above said mold and defining a common channel between said inner frame members, and outer vertical frame members disposed in outer spaced horizontal relation to each of said inner frame members on respective sides of said inner frame members opposite to said common channel;
• a linear slide member pivotally connected to said mechanism and adapted for forward extension through said common channel;
• a pair of inner drive crank members each member pivotal to an inner frame on opposite sides of said channel and pivotally connected to said linear slide member so as to be rotatable in response to linear movement of said linear slide member;
• a pair of outer drive crank members each pivotal to one of said outer frame members forwardly of said inner drive crank members;
• and
• a follower linkage including a pair of drag links interposed between each pair of inner and outer drive cranks on opposite sides of said frame for downward extension therefrom, the drag links of each pair being pivotally connected at their upper ends to upper free divergent ends of said drive crank member, and the lower ends of said drag links pivotally connected to axially spaced locations on said cutting tool whereby to impart rotational movement to said cutting tool through an arc corresponding to the curvature of the surface portion to be milled.