for better visibility, and the capacity of the snow-holding tank was increased. From the late 1950s to 1964, there were minimal changes in how the ice-resurfacers were designed. The introduction of the HD series in 1964 saw a shift in the design of the Zamboni ice resurfacers. Instead of relying on a conveyor belt system to move the ice shavings into the snow-holding tank, a vertical screw conveyor system was installed, and a new hydraulic snow-dumping system was adopted. This design has been the industry standard since it was first adopted. In 1967, an Elmira, Ontario-based welder named Andrew Schlupp founded the Resurfice Corporation and began producing competing models of resurfacers, including their popular Olympia line. In 1980 an Italian company, Engo Ice Arena Equipment, began producing ice resurfacers. Technology Ice resurfacers are generally composed of a snow container, hot water tanks, a wash water tank, the conditioner, and a board brush. Depending on the power plant, an internal combustion engine or electric motor of the vehicle is responsible both for propelling the resurfacer and also powering the hydraulics that control the various functions, such as lowering the conditioner or raising the snow dump. Most of the actual resurfacing components are contained in a heavy device at the rear of the machine, known as the "conditioner". The conditioner is hydraulically lowered to the ice surface, its weight providing the friction necessary for a large, sharp blade (similar to those used in industrial paper cutters) to shave off the top layer of ice. A horizontal auger conveyor collects these ice shavings, or snow, and funnels them to a vertical auger at the center of the conditioner. The shavings are then carried upward and sprayed into a large snow container, which takes up most of the volume of the resurfacer. The height of the blade can be adjusted by the driver, allowing deeper or shallower cuts. This is useful for keeping the ice sheet level, improving the quality of the cut, and preventing the snow container from overflowing. Wash water can be used to further improve the quality of the ice by removing debris and snow from deep skate-blade cuts. Located directly in front of the blade, nozzles forcefully spray water into the ice surface, loosening deep debris. Runners on either side of the conditioner contain the spray, while a rubber squeegee at the rear of the conditioner allows a vacuum nozzle