Abstract: The apparatus is one by which blanks are changed automatically in a hobbing machine of the general type comprising at least one tool head capable of movement along horizontal and vertical axes and consisting essentially in a horizontal spindle and a coaxial outer bearing that can be moved toward and away from one another, between which a tool is supported and set in rotation; in the apparatus disclosed, a vertical post rotatable about its own axis carries a number of peripheral supports that feature two dissimilar structures, the one designed to restrain and/or support a tool and the other a blank, in such a way that the tool currently fitted to the head can be discarded and a replacement tool supplied automatically, utilizing the one type of support, whilst the blanks are changed by the other type.

Abstract: In a hobbing machine of the type with a pair of coaxial heads driving a hob supported between them, one of which capable of movement toward and away from the other and one affording a key positioned to engage a slot associated with the hob, the slot is incorporated directly into the hob, and each head carries an axially hollow alignment spigot with a stop collar, matched to and insertable in the axial bore of the hob to a depth determined by interaction of the relative collar with the end of the hob; equipping one of the heads with a coaxial tension rod insertable through the bore of the hob, and the other head with a clamping mechanism capable of gripping and tensioning the rod, the necessary rigidity is obtained without the use of an arbor.

Abstract: Problems connected with control of the worktable in automatic gear cutting machinery are overcome by adoption of a drive system incorporating two speed reductions, the first of which a worm and wheel, the second consisting in a cylindrical gear pair with parallel shafts, one of the two members of which is backlash-compensating and split into two coaxial sections; the larger of the two cylindrical gears turns as one with the worktable.

Abstract: Equipment and method for automatically changing tools on hobbing machines. The machines are of the type equipped with a bedplate to which are connected a pair of uprights, the first of which for supporting a work head and the second of which for supporting a cutter head. The cutter head is rotatable around a horizontal axis and supports horizontally a hob at the extremities thereof. The equipment includes guide means provided in the cutter head, parallel to the axis of the hob, and a support for at least one extremity of the hob is slidable inside the cutter head along the guide means. The support is also displaceable, without being withdrawn from the cutter head, by an amount sufficient to free the two extremities of the hob from the cutter head. The equipment includes also an independent frame fixable to either one of the pair of uprights, and supporting grasping means located above the cutter head.