US 4,768,904 AGranted

Apparatus for broaching cylindrical surfaces of a workpiece, in particular of a crankshaft

AssigneeGebr. Heller Maschinenfabrik Gesellschaft mit beschraenkter Haftung

InventorKarl-Heinz Schmid

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Abstract

Apparatus for broaching a cylindrical surface of a workpiece, in which at ast one broaching tool is mounted on a tool carrier rotatable about its axis and about the axis of the cylindrical surface of the workpiece clamped in a stationary position. The broaching tool is independently rotatable about its own axis, and the rotary motion of the tool is superimposed on the rotation of the carrier and consequently the revolving motion of the broaching tool. Since the workpiece is stationary during broaching, very high cutting speeds can be achieved. The broaching tool can be of small and lightweight construction so that it is especially suitable for an automatic tool change. In a preferred form, a plurality of broaching tools are utilized, the axes of which are spaced outwardly from and circumferentially about the axis of the workpiece.

Claims8

Dependent claims

Apparatus for broaching cylindrical surfaces of a workpiece such as, for example, a crankshaft, comprising:

means for clamping the workpiece to be machined, said workpiece being held stationary during the broaching process;
a tool carrier adapted to carry tools and to be mounted for rotation about an axis relative to the cylindrical surface of the workpiece;
first drive means for rotating said tool carrier, said first drive means determining the cutting speed of the tools;
a plurality of broaching tools mounted on said carrier for rotation therewith, each of said broaching tools being so shaped that when said tools are in a withdrawn position, a central opening is formed having a dimension greater than the effective diameter of the workpiece so as to permit movement of said tools axially relative to said stationary workpiece;
a shaft mounting each of said broaching tools for rotation about the axis of each shaft, the axes being positioned radially outwardly from and about the axis of rotation of said tool carrier, and
means for rotating each of said broaching tools about its own axis independently of the rotation of said tool carrier, the rotation of said broaching tools controlling the feed and being superimposed on the rotating motion of said tool carrier thereby permitting very high cutting speeds to be achieved.

3 more elements

Dependencies are inferred from the claim text.