Cast formed bi-metallic worm assembly and method

US5188023A · kind A · utility

Assignee

• The Dupps Company · US

Inventors

• Peter W. Mansfield · Urbanna, US
• Frank N. Dupps · Germantown, US

Key dates

• Filing date: Oct 30, 1991
• Grant date: Feb 23, 1993
• Expiry date: Oct 30, 2011

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B22D19/16
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A cast-formed bi-metallic worm assembly of a mechanical screw press for expressing liquids from fibrous materials and a method of manufacture therefor and the product produced by the method. The worm assembly is rotatably driven by the press drive shaft and includes an outer flight body having an integral outwardly extending helical flight formed of a relatively brittle, wear-resistant homogeneous cast material and an inner hub tightly fitted and substantially fully mated within, and coextensive with, the outer flight body. The inner hub, cast formed of a more ductile, tougher homogeneous material, includes a hollow cylindrical interior surface structured for slidable engagement around and in driving connection with the drive shaft. The inner hub and outer flight body are securely engaged one to another by cast forming the outer flight body around the precast inner hub. Longitudinal lobes in a smooth undulating in and out clover leaf cross sectional pattern further increase rotational or torsional strength of the worm assembly without appreciably increasing internal operating stress between inner hub and outer flight body.