GUIDE-BAR DEVICE FOR AUTOMATIC LATHE AND METHOD OF FABRICATION THEREOF

摘要

The device comprises essentially a body (1) or shaped piece of cylindrical form and of a circular or polygonal cross section, comprising tubular cavities (2 - 5) of different diameters for receiving the bars (B) to be machined of different diameters and/or profiles. The tubular cavities (2 - 5) can comprise longitudinal distribution channels (11) for feeding oil under pressure to the bar (B) to be machined. The cylindrical body (1) further comprises indexing grooves (23) at its external periphery, means of distribution of oil (13) at the rear part of the device, an oil extractor (16) located at the front part of the device and cavities (7, 8) permitting the return of the oil to a hydraulic group (20). Reinforcing ribs (10) are provided between the tubular cavities (2 - 5) and between the latter and a mantle of the cylindrical body (1) so that the latter has a great moment of inertia which ensures a good stability of the device. The tubular cavities (2 - 5) may comprise tubes (18) aligned along the longitudinal axis of the cavities and rotating freely with play in these tubular cavities (2 - 5). These tubes (18) are the proper guiding tubes and they protect the tubular cavities (2 - 5) against the damages which could be caused by the fast rotating bars (B) to be machined. These tubes (18) permit also to create a double hydrodynamic bearing permitting to impart very great speeds of rotation to the bars (B) to be machined.