| 摘要 |
661,485. Edge filters. PUROLATOR PRODUCTS, Inc. March 11, 1949. [March 25, 1948] No. 6712/49. Class 46. [Also in Groups V and XXVIII] An edge filter unit e.g. for use in oil filters of internal combustion engines comprises a helix composed of thin narrow plastic ribbon 11 Fig. 4 with its width substantially normal to the axis of the helix and spacing members 12 integral with the ribbon, extending from the wider face of the ribbon into engagement with the adjacent faces, to which. they may be permanently bonded so as to space the turns of the helix and provide interstices of definite width between the adjacent turns of the helix. Aligning means may be provided integral with the ribbon such as the lugs 14a, Fig. 5 having apertures 16a therein through which rods may be passed. The ribbon may be formed by extruding plastic materials from a nozzle in the form of a wire which is passed between rollers, one of which has recesses therein corresponding to the spacing members 12 and lugs 14a or other details (see Group V). In a modified form of ribbon each rib 12 is provided with a radial extension or lug with a shoulder piece adapted to be engaged by adjacent turns of the ribbon to prevent lateral displacement of the turns. The ribbon may have a tapering crosssection.
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