Collection tank

A mobile backfill system for collecting material, comprising:

• a wheeled vehicle chassis;
• a collection tank mounted to the chassis and comprising a body having
• a closed end,
• an open end opposite the closed end and having a generally circular periphery,
• a central, generally cylindrical section extending between the closed end and the open end, and
• a door having a generally circular periphery and that is pivotable about a first axis between a first position, at which the door is spaced from the open end of the body, and a second position, at which the generally circular periphery of the door seats against the generally circular periphery of the open end, thereby closing the open end;
• a vacuum pump mounted to the chassis and connected to the collection tank that draws an air stream through the collection tank for carrying material into the collection tank;
• and
• two dual arm linkages, each dual arm linkage
• extending between a respective first pivotal connection between said dual arm linkage and the door and a respective second pivotal connection between said dual arm linkage and the tank body, and
• having a first arm connected to the door at the respective first pivotal connection and a second arm connected to the body at the respective second pivotal connection, wherein the first arm and the second arm are pivotally connected at a respective third pivotal connection,
• wherein the two dual arm linkages are arranged on opposite sides of the collection tank so that
• a second axis extending through the first pivotal connections, a third axis extending through the second pivotal connections, and a fourth axis extending through the third pivotal connections are parallel to each other and to the first axis,
• when the door is in the first position, the first axis, the second axis, and the fourth axis are on a first side of a plane that includes the third axis and that, when the door is in the second position, also includes the second axis, and
• when the door is in the second position, the fourth axis is on a second side of the plane, opposite the first side of the plane.

A mobile backfill system for collecting material, comprising:

• a wheeled vehicle chassis;
• a collection tank mounted to the chassis and comprising a body having
• a closed end,
• an open end opposite the closed end and having a generally circular periphery,
• a central, generally cylindrical section extending between the closed end and the open end, and
• a door having a generally circular periphery and that is pivotable about a first axis between a first position, at which the door is spaced from the open end of the body, and a second position, at which the generally circular periphery of the door seats against the generally circular periphery of the open end;
• a vacuum pump mounted to the chassis and connected to the collection tank that draws an air stream through the collection tank for carrying material into the collection tank;
• two dual arm linkages extending between respective first pivotal connections between the respective dual arm linkage and the door and respective second pivotal connections between the respective dual arm linkages and the tank body;
• and
• a shaft extending entirely across an interior of the central, generally cylindrical section along an axis passing through the second pivotal connections.