| 摘要 |
PURPOSE:To eliminate oil shortage and overflow, by making an oil storage groove, traversing threads of a screw, and an oil drain groove, in the rear flank of the screw, at the helicoid of a lens barrel. CONSTITUTION:A lens barrel body 20 has three split screw parts 20a and thread- uncut parts 24. To store lubricating oil for the screw parts, oil storage grooves 21 are cut each except at the front and rear ends of the screw part. So that oil overflowing to the thread-uncut parts will not contaminate a lens part and a diaphragm part, a circular oil drain groove 23 is cut in the rear flank of the screw part. Thus, two kinds of grooves are provided to facilitate the restriction of the applied amount of lubricating oil and to prevent leaching to other parts. |
