Bilgram bevel gear generating machine

The first machine to use a reciprocating rack-tooth cutter on the moulding-generating principle was invented by Hugo Bilgram in 1 884 to produce bevel gears. The machine in the Collection is the automatic version introduced by Bilgram in 1901.

The machine is basically a shaper, but the gear-blank is given a rolling motion in relation to the reciprocating cutter. The gear-blank carrier swings about a vertical axis and at the same time causes the blank to rotate. This latter motion is brought about by means of a pair of steel bands attached to the frame and also attached to and wrapped about a portion of a conical surface on the axis of the blank. The apex of the cone lies on the pivotal axis of the carrier.

The resultant motion given to the blank is the same as it would receive if it were rolling in gear with a circular rack. The cutting edge of the tool corresponds to a side of the rack tooth, and its action is to generate on the blank a conjugate tooth which has octoidal form.

The indexing mechanism spaces the teeth, and the feed rotates the blank slightly after each series of cuts.