Helical screws with flights of superimposed strips - for cheap mfr. of various lightweight or solitary screw forms

摘要

Helical screws are made by winding superimposed flexible profiles along a supporting shaft and keying the superimposed strips to each other and to the root shaft by welding, adhesives, mechanical fastening, etc. The process is used for mfr. of lightweight, corrosion resistant screws for conveying materials, extruding slurries, etc. Screws may be assembled in a single pass through the equipment applying the superimposed layers successively. Different screw profiles may be obtd. by varying the axial and rotational shifts of the shaft relative to the strip winding units. The process is quicker than machining from solid or assembly of longitudinal segments of the flight and/or screw, and need not require prefabricated patterns, thus reducing prodn. time and costs.