Towed paver with thickness and leveling control

Claim 1

The combination of a towed paver and grade sensing and control means therefor, the paver comprising a hopper having front and back walls with a material depositing opening therebetween, at least two vertically adjustable supporting wheels beneath said front wall, a screed attached to the back wall of said hopper in fixed relation thereto and extending rearwardly of said material depositing opening, extendible devices between said wheels and the front wall of said hopper and a power source for said extendible devices whereby said hopper and screed may be moved relative to said wheels as said paver is towed over a surface to be paved; said sensing and control means comprising skis movably supported on said hopper and engaging said surface to be paved, means on said hopper connected to said skis for emitting a signal, secondary means controlling said power source with respect to said extendible devices and acting responsive to said signal to move said extendible devices and the hopper and screed responsive to movement of the skis due to deviation in the grade of said surface to be paved so as to change the angle of attack of said screed.