Abstract: A hobbing machine for manufacturing spur and worm gears comprises a tool support provided with a support carriage movable in the direction of the axis of the blank to be machined and carrying a milling head provided with a separate feed drive which actuates via a branch gearing axial and tangential feed gear element and is connected via differential gears to a gear train for a hob. The branch gearing is arranged in the movable support carriage and includes a switch wheel which is engageable either with a drive wheel of the axial feed gear train or with the drive wheel of the tangential feed gear train and is controlled by a switching lever located on the support carriage.

Abstract: A device, such as a damper or valve, for use in closing a conduit against the flow of liquid has a chamber surrounding and opening into the conduit. A blade at one side of the conduit is movable through the chamber from a first position within a bonnet into a conduit-blocking position. Means carried by the chamber side walls surround the conduit and are between the conduit and the blade when in its first position and are operable then to coact to seal the chamber against leakage into it and to seal the blade when in its second position. At least one seal is of a type brought by fluid under pressure from a position out of the path of the blade into its sealing positions and is carried by the side wall enabling the seal to engage the blade face exposed to the fluid flow. Means are provided to deliver fluid pressure to the pressure operated seal when the blade is in either position and to relieve the pressure therein when the blade is to be moved.

Abstract: Pitch generation method for the production of bevel gears and mainly for the rough hobbing of pinions, with working of the pinion blank during generating of the tooth profiles, using a single cutter head for working both flanks of each tooth space. The generating speeds and ratio of roll of the cutter head, as well as the profile angle of the cutters are kept uniform. The desired, curved outlines of the tooth flanks, establishing a tapering tooth space, are generated by a simple mechanism which generates the proper motions of the gear cutters. For this purpose the cutter head is pivoted, opposite the workpiece or gear blank, in a drum, for several swiveling motions.