Friction Shaft for Slitter

A friction shaft for a slitter that has winding tubes disposed on an outer surface thereof to roll unit materials formed by cutting a raw material such as various kinds of paper, fabric, or film with predetermined intervals,

• the friction shaft comprising a first rotary shaft rotated by a driving motor and supplied with compressed air from an air supplier,
• wherein, in the first rotary shaft, a moving passage elongated in a longitudinal direction of the first rotary shaft is formed in the first rotary shaft, first and second supply holes for receiving the compressed air are formed at a side of an outer surface to be connected with the moving passage, moving holes connected with the moving passage are formed with predetermined intervals at an opposite side of the outer surface in the longitudinal direction of the first rotary shaft and are arranged around the first rotary shaft with predetermined intervals, first discharge holes are formed at the opposite side of the outer surface to be longer than the moving holes in the longitudinal direction of the first rotary shaft and are arranged with predetermined intervals around the first rotary shaft between the moving holes, locking steps protrude from open ends of the first discharge holes, and connection holes connecting the moving passage and the first discharge holes are formed therein,
• the friction shaft includes tubes disposed in the first discharge holes and having third supply holes connected with the connection holes,
• the friction shaft includes brake pads for torque that are disposed in the first discharge holes to be adjacent to each other, have a first friction portion protruding from an outer surface thereof, and have a locking portion protruding from the outer surface around the first friction portion to be locked to the locking step,
• the friction shaft includes a second rotary shaft disposed to be movable through the moving passage,
• wherein, in the second rotary shaft, moving grooves for sending compressed air supplied from the second supply holes to the connection holes are formed in a circular shape and elongated on a side of an outer surface in a longitudinal direction of the second rotary shaft, and first fastening holes facing the moving holes are formed with predetermined intervals on an opposite side of the outer surface in the longitudinal direction of the second rotary shaft and are arranged with predetermined intervals around the second rotary shaft,
• the friction shaft includes pressing members fastened in the first fastening holes and exposed from the moving holes,
• the friction shaft includes first rotary tubes disposed on the outer surface of the first rotary shaft to be adjacent to each other in the longitudinal direction of the first rotary shaft with the winding tubes on outer surfaces thereof,
• wherein, in each of the first rotary tubes, a second friction portion that generates friction with the first friction portion protrudes from an inner surface, first and second fitting spaces are formed at both sides of the second friction portion, fitting holes are formed on a side, which faces the second fitting space, of the second friction portion with predetermined intervals around the first rotary tube, and second discharge holes connected with the second fitting space are formed on an outer surface with predetermined intervals around the first rotary tube,
• the friction shaft includes second rotary tubes disposed on the outer surface of the first rotary shaft and movably fitted in the second fitting spaces,
• wherein, in each of the second rotary tubes, locking holes facing the second discharge holes are formed on an outer surface with predetermined intervals around the second rotary tube, first inclined surfaces are formed in the locking holes, fitting holes facing the fitting holes are formed on the outer surface with predetermined intervals around the second rotary tube, locking steps protrude at a side of an inner surface close to the fitting holes, and a third fitting space is formed at an opposite side of the inner surface,
• the friction shaft includes first and second bearings that are fitted in the first and third fitting spaces, respectively to be locked to the second friction portions and locking steps and are disposed on the outer surface of the first rotary shaft,
• the friction shaft includes first elastic members fitted in the fitting holes,
• the friction shaft includes guide members that are disposed in the second discharge holes, have a second inclined surface formed at a side of an outer surface to be guided by the first inclined surface, have a locking hole formed at an opposite side of the outer surface, and have a second fastening hole formed on the outer surface around the locking hole,
• the friction shaft includes second elastic members fitted in the locking holes of the pressing members,
• the friction shaft includes lugs for clamping that are disposed in the second discharge holes and have a third fastening hole connected to the second fastening hole by a fastener,
• when the compressed air is supplied to the moving passage through the first supply hole, the second rotary shaft is moved through the moving passage by pressure of the compressed air and the pressing members are moved through the moving holes, the second bearings and the second rotary tubes are sequentially pressed by the moving pressing members, and the second inclined surfaces are guided by the first inclined surfaces, so the lugs for clamping are discharged from the second discharge holes and the discharged lugs for clamping come in close contact with inner surfaces of the winding tubes, and
• when the compressed air is supplied to the third supply holes sequentially through the second supply hole, the moving grooves, and the connection holes, the tubes are expanded and the first friction portions of the brake pads for torque are discharged from the first discharge hole and come in close contact with the second friction portions of the first rotary tubes.