PURPOSE: To prevent a scattering of leaking lubricant oil by covering a supply pipe with a mild steel pipe having a bore larger than the major diameter of the supply pipe and formed in a specific form a little shorter than the supply pipe, and fixing its one end to one side metal fitting of the supply pipe.

CONSTITUTION: A supply pipe 1 formed with a soft material, in which metal fittings 2a and 2b are fixed by a calking to both ends, is covered by a mild steel pipe 4 whose bore is larger than the major diameter of the supply pipe 4 and the length is a little shorter than the supply pipe 1. This mild steel pipe 4 is formed in a specific form beforehand, and fixed to one side metal fitting 2a of the supply pipe 1 by a calking tool 5. And the other end of the mild steel pipe 4 is formed in an opening 1a placing a specific interval to the metal fitting 2b. As a result, an external damage to the supply pipe 1 is prevented by the mild steel pipe 4, the leaking lubricant oil is led to a specific position by the mild steel pipe 4, and a scattering of the lubricant and a fire breaking can be prevented.