Snow pusher
From Wikipedia, the free encyclopedia
Snow pushers (also known as box plows, containment plows, or box style plows) are designed to move snow by pushing it straight ahead. They do this by being constructed with a curved moldboard that lies perpendicular to the direction of travel and a sidewall at either end that keeps the snow contained. For parking lots, runways, ect. this is an improvement on the traditional windrow plowing, which uses an angled plow to move snow to the side. Snow Pushers allow the snow to be moved en mass and completely off site to be piled someplace out of the way.
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[edit] Snow Pusher History
Snow Pushers have been in use since the 1970s, though they did not come into widespread utilization until the 1980s. Initially they were not sold by any manufacturers, but were recognized as a good idea by snow removal professionals who either welded their own or contracted to have them fabricated. For a long time the most common pusher design was to take septic tank or other large steel cylinder and cut it in half, then build a mounting system on the back to attach it to a machine. This type of bare bones construction lasted until the 1990s when a welder and steel fabricator named Mike Weagley of Pro-Tech Manufacturing and Distribution started producing them commercially.
[edit] Snow Pusher Design
Snow Pusher designs vary across the industry. They typically are between 3 feet and 5.5 feet tall and range from 6 ft to 30 ft wide. Pushers are typically mounted on wheel loaders, Skidsteers, or Backhoes. For loaders and backhoes they are mounted using a universal mounting system that was pioneered by Pro-Tech and adopted by the rest of the industry. It consists of a set of posts between which the bucket is placed. Chains are attached to the pusher and the bucket and tightened using a chain binder. This system allows for pushers to be mounted on only machine without regard for brand specific mounting brackets. Skidsteer Loaders can use the universal mounting system, however most manufacturers typically offer skidsteer pushers with a universally accepted coupler system. Though the snow pusher might seem like a simple product there are many variations across the industry in areas such as, moldboard height and angle, sidewall support system (post, wedge, or unsupported), trip system (for steel edged pushers), shoe thickness, and several other areas.
[edit] Steel vs. Rubber edged Pushers
Snow pushers can be divided into two separate families, steel and rubber edged. Both are used in the same fashion to move snow. Rubber edged pushers have a composite material mounted on the bottom of the moldboard which lies flush to the ground and keeps snow from passing under the pusher getting a cleaner push then otherwise. Rubber edges are able to flex and pass over obstructions with ease.
Steel edge pushers have a spring loaded steel cutting edge mounted to the bottom of the moldboard that allows pushers to scrape the pavement. These edges get the pavement cleaner then the flexible rubber edges and are able to break up ice. The downside to steel edged pushers are the lack of flexibility which means that they need to employ a tripping system to allow them to pass over obstructions such as uneven pavement or raised manhole covers. There are three types of trip edges in use today, compression spring, torsion spring, and composite material springs. Both compression and torsion springs work similarly, the steel edge is mounted on a hinge and is held in place by the pressure of the springs, when the edge meets an obstruction the springs compress and allow the edge to flip back and under the pusher and to pass over the obstruction. Composite material trip edges can act like a rubber band when the edge meets an obstruction allowing the steel edge to flip under the pusher and then snap back into place. The advantage provided by this is the lack of moving parts to break and the simplicity of the design (a key selling point for almost all snow pushers).
