changes direction at the distal ends of its swings a method is employed to limit the amount discharged to prevent 34 double coating 34 at the edges as noted before prior art systems such as described in bellafoire 39 973 and of autofoam u00ae company shut the nozzle off at these portions of the cycle however this action causes several problems for example the on off cycling has detrimental effects on spray material consistency from a chemical reaction point of view the on off cycling also causes mechanical wear and induces metal fatigue on brackets that must react to cyclic pressure loading in contrast to the devices of bellafoire 39 973 and of the autofoam u00ae company the present invention uses a geometric arrangement and constant liquid product flow to prevent pattern edge build up for example fig3 shows a cross section of rails 24 and 25 in the middle of the transverse sweep carriage plate 26 driven by end bushing 27 on telescoping extension 19 is shown with brackets 65 and 66 attached brackets 65 secure top rollers 29 with concave 34 hourglass 34 contours similarly contoured bottom rollers 53 are secured by brackets 66 thus rollers 29 and.