Patent ID: 7175176

Claim:
A device for feeding one of suction air and blowing air to a sheet-retaining device displaceable relative to a machine element in a sheet-fed rotary printing machine having a reversing device and a cylinder with a periphery, the machine element being a suction gripper of the reversing device pivotable out of the periphery of the cylinder of the printing machine, the air feeding device comprising: a first air-feeding element to be connected in terms of flow to an air source for one of suction-air and blowing-air; a second air-feeding element cooperating telescopically with said first air-feeding element for forming an air through-passage duct connected in terms of flow to the sheet-retaining device; said first and second air-feeding elements being first and second hollow tubes to be inserted telescopically inside one another; said first hollow tube being sealed by a sealing element relative to said second hollow tube, for preventing an escape of leakage air; said sealing element including a first sliding sealing ring disposed between an outer surface of said first hollow tube and an inner surface of said second hollow tube, and fastened onto said first hollow tube, and a second sliding sealing ring fastened onto said inner surface of said second hollow tube and together with said first sliding sealing ring defining an annular interspace between said outer surface of said first hollow tube and said inner surface of said second hollow tube.