U.S. Philips Corporation

Johannes M Swinkels

Marinus J Dona

A support device for a drum (1) which is provided with two journals (57, 59) projecting from the drum on either side of the drum, whose centerlines (25, 27) substantially coincide with the centerline (9) of the drum. Each of the two journals (57, 59) is journalled around an axis of rotation (61) in a bearing bush (63, 65) which is attached to a frame (67) by a ring-shaped membrane (69) positioned in a plane transverse to the axis of rotation (61). Each of the two journals (57, 59) forms part of a shaft (17, 19) projecting into the drum (1), and attached to a shell (7) of the drum by a ring-shaped plate (11). An end of a portion of each shaft (17, 19) projecting into the drum (1) bears on adjustment devices (41, 43, 49) by which the relevant shaft (17, 19) with journal (57, 59) can be swivelled relative to the centerline (9) of the drum (1). In particular, such a support device is used for a drum (1) which serves as a rotating carrier for a plate-shaped workpiece which is to be machined accurately by a cutting tool, such as, for example, a master for the production of projection television screens.

Support device for a drum

A machine tool comprising a third carriage which is guided along a circular cylindrical guide of a second carriage by means of a static fluid bearing and which can thus rotate about an axis of rotation which coincides with a centerline of the circular cylindrical guide. A working point of a tool fastened to the third carriage lies on the axis of rotation so that an angular adjustment of the tool effected by rotation of the third carriage can take place independently of a position adjustment of the working point effected by a displacement of the second carriage and a first carriage. The machine tool can be used for the processing of surfaces, in particular in the manufacture of linear and circular Fresnel lenses for projection television screens by means of a cutting tool.

Positioning device having static fluid bearings

A method of manufacturing a master for projection screens, according to which a pattern of parallel rectilinear grooves and ribs is formed on one side of a plate of machinable material by a slotting operation performed by means of a profile chisel. The grooves (33) are formed in several different tooling steps, with several grooves being tooled simultaneously. The profile chisel is of multiple construction and is composed of three subchisels, i.e. a precutting chisel, a cutting chisel (13) and a finishing chisel.

Method of manufacturing a master for the fabrication of projection

A method of manufacturing a master for projection screens, according to which a pattern of parallel rectilinear grooves (31) and ribs (31) is formed on one side of a plate of machinable material by a slotting operation performed by means of a profile chisel. The grooves (33) are formed in several different tooling steps with, several grooves being tooled simultaneously. The profile chisel is of multiple construction and is composed of three subchisels, i.e. a precutting chisel, a cutting chisel (13) and a finishing chisel.

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Eindhoven, Netherlands

Johannes M Swinkels