| 摘要 |
396,385. Emery and sand cloth &c. BEHR-MANNING CORPORATION, Troy, New York, U.S.A. Feb. 1, 1932, No. 2971. Convention date, Nov. 20, 1931. [Class 60.] In the manufacture of sand paper and like abrasive material, the abrasive particles are propelled on to the backing material by an electrical field. The abrasive particles are disposed in a hopper 10 and fed therefrom by a roller 12 on to a travelling conveyer 13 in a layer of desired density. The backing material 14 is coated at 15 with adhesive and is passed in promimity and parallel to the conveyer 13, coming into an electrical field produced by an electrode 17, and if desired an earthed electrode 13<1> contacting with the conveyer ; the field causes the abrasive particles to be lifted from the conveyer and deposited on the backing. In a modification, the hopper has an upturned mouth from which the abrasive particles are attracted by a charged electrode from which they are moved to the adhesive coated backing, passing beneath the electrode, by the electrical field between the electrode and another situated below the backing. The electrode 17 may rotate, and preferably is negatively charged.
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