PURPOSE: To improve lubricating performance and the accuracy of dies, by constituting the required number of oil grooves directly and easily on a helicoid which is a sliding part.
CONSTITUTION: A lens system L constitutes a part of a focusing system of, for example, a video camera or the like and is used as a camera together with the other lens system. The focusing operation is accomplished by the rotation and sliding of a helicoid 9 with the other helicoid 12 facing said helicoid. An oil groove 10 is constituted preferably to a shape deeper than the trough 9a of the helicoid 9, and is used preferably as a well for grease. Said groove may be formed simply by removing the tooth profile to the same depth as the root of the trough. The groove 10 is constituted freely on the circumference of the helicoid.
YOSHIOKA TOSHIAKI
SANO KENJI
SATOU HIRONOBU
