Asphalt shingle, roof covering therewith and method of making the same with synchronized adhesive positioning thereon

A method of making an asphalt shingle in a manufacturing environment in which the shingle has a headlap region and a tab region, with granules applied to an upper surface of the shingle that is to be weather-exposed in the installed condition on a roof, the method comprising:

• (a) providing a shingle-forming layer comprised of shingle reinforcement material impregnated with a bitumen material, the layer having a butt region and a tab region, and including the step of delivering the layer along a predetermined path;
• (b) providing a layer of granules on an upper surface of the shingle-forming layer;
• (c) applying a substrate layer with a plurality of indicators carried thereby to the shingle-forming layer, with the indicators being provided at predetermined spaced-apart distances from each other;
• (d) sensing the locations of the indicators;
• (e) then actuating the placement of adhesive zones onto the upper surface of headlap portions of the shingle-forming layer and synchronizing the placement of the adhesive zones on the upper surface of the shingle-forming layer in response to the sensing step of clause (d);
• and
• (f) cutting the shingle-forming layer into individual shingles,
• wherein the tab region of the shingle comprises a plurality of tabs defined by slots formed through the entire thickness of the shingle and extending from a lower edge of the tab region to the headlap region, each tab having a centerline, each slot having a length L and a width W, and
• wherein the adhesive zones are placed leaving adhesive-free zones on the upper surface of the headlap region registered with the centerlines of the tabs, such that no adhesive is disposed in registration with the centerlines, each adhesive-free zone having a length of at least L and a width of at least W.