Harvester with easy access to grain tank

A combine harvester comprising a grain tank, said grain tank including:

• a receptacle having sidewalls and an upper edge formed of straight edge portions,
• a cover comprising panels which are pivotably coupled respectively to said edge portions, the cover further comprising collapsible connections between each pair of adjacent panels so that:
• (i) the panels act as lids that are configured to close or open the receptacle, and
• (ii) when the panels are fully deployed to thereby open the receptacle, the cover forms a funnel-shaped extension of the receptacle,
• wherein one of the panels comprises an aperture and a pivotable door that is configured such that when the cover forms said funnel-shaped extension, the door is pivotable about a substantially horizontal hinge axis between a first position where the door is coplanar with said one of the panels and secured thereto and thereby closing-off said aperture, and a second position, wherein in said second position:
• (i) the aperture is open,
• (ii) the door is supported by a support structure of the combine harvester, and
• (iii) the door forms a walking plank that provides access to the receptacle of the grain tank through the open aperture.