Lens barrel for a microscope

A lens barrel for a microscope including:

• an eyepiece barrel provided for rotation relative to a barrel body;
• a reflecting mirror holder for holding on the rotational center axis of said eyepiece barrel a reflecting mirror having a reflecting surface for reflecting light from an objective lens, and for rotating said reflecting mirror about said rotational center axis;
• and
• first and second circumferential surfaces formed on said eyepiece barrel and said reflecting mirror holder, respectively, said first and second circumferential surfaces having respective centers of curvature coincident with said rotational center axis and having a ratio of diameters of approximately 1-to-2;
• a pulley rotatably supported on said barrel body for rotation on an axis spaced from and substantially parallel to said rotational center axis;
• the spacing between said rotational center axis and said rotation axis of said pulley being adjustable;
• and
• elongate connecting means wound over and connecting said first circumferential surface, said second circumferential surface, and said pulley for transmitting rotation between said first circumferential surface and said second circumferential surface by way of said pulley.