1.  Field of the Invention
The present invention relates to a mowed grass amount detecting apparatus for detecting an amount of mowed grass in a grass collection container for a grass mowing machine, the grass collection container receiving grass mowed by a mower unit though a conveying duct. 
2.  Description of the Related Art
A mowed grass amount detecting apparatus for detecting an amount of mowed grass in a grass collection container for a grass mowing machine is known from e.g. JP 6-153653 A (para. [ 0027]-[0029], FIG.  3). 
This mowed grass amount detecting apparatus includes an optical sensor unit consisting of a light emitting portion and a light receiving portion mounted inside a housing which covers the grass collection container, and a fullness detecting unit for detecting fullness of the amount of mowed grass in the grass collection container, based on an output signal from the optical sensor unit.  With this conventional art, a bracket for mounting the optical sensor unit and the fullness detecting unit or its support or a signal line extending from the optical sensor unit to the fullness detecting unit can be an obstacle which blocks the flow of mowed grass, thereby causing such problem as entanglement or jamming of the mowed grass.  If a curved cover for covering such bracket and/or signal line is provided for reducing such interference, this will reduce the entanglement or jamming of mowed grass, but since the cover protrudes inside the grass collection container, there occurs a new problem of reduction in the capacity of the grass collection container.