Snowplows for frontal mountings on road vehicles generally are raised by the movement of a hydraulically operated piston encased in a cylinder, the moldboard with a blade on a large highway snowplow may weigh as much as 1500 to 3000 pounds.
It has been proposed to equip snowplow moldboards and blades with force limiters which permit the blade and moldboard to move backward and upward for cleaning obstacles (U.S. Pat. No. 3,587,182), with blade-directing and tripping devices for snowplows (e.g., U.S. Pat. No. 3,893,578), and various runners, skids shoes or caster wheels for sensing a surface by contact and, in some cases, "planing" a snow covering on a road.
Also, in the road grader art, it has been proposed to regulate the depth of cut or scraping by use of a wave energy distance sensor, of the ground, the sensor being mounted on the equipment.
The weight of the snowplow moldboard equipped with a blade, together with the speeds at which the vehicle-mounted snowplows frequently operate, particularly large highway plows, often makes for much blade wear and necessitates frequent blade replacement. Eight to ten hours of rugged highway service has been known to wear out a snowplow blade.
The present invention provides a way for reducing such blade wear and extending the operating life of the blade. In essence, it is based on regulating the fraction of moldboard and blade weight that is supported by the surface being scraped e.g., highway pavement, at a value which is effective for scraping such as snow and/or ice removal from said surface but lower then the full weight of the moldboard and blade. Such value can be, say, about 10-90% of such full weight and move frequently about 20-40% with concomitant lessening of blade abrasion.