Patent ID: 9570891
Date: 2017-02-14
CPC Classifications: F16F,F16N,H01H,H02B

Claim:
1. A method of lubrication of a buffering device of a movable electrical contact in an operating mechanism of a switchgear, the buffering device comprising an outer cylinder, and an internal cylinder provided in the outer cylinder and at least partially defining a pressure chamber for an operating fluid, the method comprising steps of: arranging a lubricating plug at an end of an internal cylinder of said buffering device, a tip of said lubricating plug having a packing to seal the pressure chamber of the internal cylinder of said buffering device; providing a flow path in an interior of said lubricating plug, said lubricating plug being connected with a conduit that bifurcates into two branches; connecting one of said conduit branches with a vacuum pump; connecting another of said conduit branches with a container of the operating fluid; arranging a first valve on said one of said conduit branches; arranging a second valve on said another of said conduit branches; closing said second valve while opening said first valve and operating said vacuum pump, to put the pressure chamber into a vacuum condition; thereafter closing said first valve and opening said second valve, to introduce the operating fluid in said container into the pressure chamber and thereby lubricate the buffering device; and thereafter replacing said lubricating plug sealing the pressure chamber with another plug that seals the pressure chamber, wherein the another plug is coupled for movement with the movable contact.