PURPOSE: To remarkably reduce the flow noise of a drum by a method wherein a layer having a sound absorbing function is provided in a hollow chamber opposite to air efflux openings in a drum casing.
CONSTITUTION: A hollow camber 12 is divided in respective chambers by means of walls extending radially and axially from a drum body 2 to a drum casing 8. These chambers are connected through feed passages 17 successively to an air feeding part during the rotation of an air cushioning drum 1. To a lattice work 13, a layer 18 made of a material having a sound absorbing function such as a foamed material is fixed. In order to allow to pass air, the layer 18 has a large number of radial passages 19. The outside of the layer 18 is covered by a layer 20 of stable form. By means of this layer, the layer 18 is held onto the lattice work 13. This layer 20 receives outward radial flow force and centrifugal force. Similarly, the passages 19 run through the layer 20. since the outer surface of the layer 20 locates apart from the drum casing 8, the air can freely enters towards the whole inner surface of the drum casing 8. In addition, owing to the interval between the layer 20 and the casing 8, the sound absorbing function of the layer 18 is enhanced.
| JPH08332769 | SHEET FEEDER FOR PRINTER |
| JPH05169628 | PAPER FEEDER FOR SHEET-FEED PRESS |
HARII BURANDESU
RUUDORUFU RAAPU
| JPS6147264A | 1986-03-07 | |||
| JPS56164897A | 1981-12-18 |