Apparatus for embossing moving webs

Claim 1

In an apparatus for marking a moving workpiece by pressing a transfer tape having a coating of marking material thereon into engagement with the moving workpiece, said apparatus including driven conveyor means for conveying the workpiece past a work station, an embossing die carried by an arm mounted for pivotal oscillatory movement about an axis extending transverse to and spaced from the path of movement of the workpiece at the work station, tape feed means for advancing the transfer tape through said apparatus, and drive means for driving the embossing die support arm in its oscillatory movement and for shifting the pivotal mounting of the arm toward and away from the work station in synchronization with its oscillatory movement to drive the embossing die along a closed path including a work stroke portion in which the die moves at the same rate and tangential to the workpiece with the transfer tape pressed therebetween and a return stroke portion spaced from and in a generally opposite direction to the work stroke, the improvement wherein said tape feed means comprises an articulated four-bar linkage including first and second elongated bars each having one end pivotally supported on a common ground and extending in spaced relation in the same general direction, a third bar extending between and having its opposed end portions pivotally connected to said first and second bars, a braked tape supply reel and a driven take-up reel, guide means on said first and second bars at points spaced from their respective pivotal supports for guiding the tape between said supply and take-up reels with a length of the tape extending between the guide means on said first and second bars and generally tangential to the path of said embossing die during said work stroke, drive means oscillating said first and second bars about their respective pivotal supports in synchronization with said embossing die to move said length of tape in the same direction and at the same speed as said embossing die during at least a portion of said work stroke, said third bar being pivotally connected to said first and second bars at points spaced unequal distances from their respective pivotal supports to produce a shorter movement of the guide means closest said take-up reel to thereby shorten said length of tape during its movement parallel to said die during said work stroke, and friction clutch drive means driving said take-up reel to take up a length of tape equal to the amount said length is shortened on each said work stroke.