Three-year-old Cory James from Thrapston, Northamptonshire died on 13 June when he fell from a tractor as his grandfather mowed a playing field.
James' grandfather Christopher Mayes, 55, was arrested but following a police investigation no charges were made.
The inquest at Kettering Magistrates' Court heard James' death was the result of head injuries.
Mayes told the inquest how James had run across the grass and asked to get into the tractor.
He had ridden the tractor on previous occasions and was allowed to as a treat.
While James was riding the tractor he saw his father, Simon, across the field with a present for him.
The court then heard how the three-year-old had caught sight of the toy helicopter and forced his way past his grandfather to get down from the tractor, despite Mayes attempts to stop him.
Northamptonshire Police said Cory's death was a "tragic accident".
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