Gear checking machine

Claim 1

A gear checking system for measuring a characteristic of a gear comprising a base member for rotatably supporting the gear, support means carried by said base member, rotating drive means for driving said support means and said gear so they rotate together, at least one means for measuring displacement including a fixed portion and a relatively movable element which engages said gear, and signal means responsive to displacements of said movable element with respect to said fixed portion so as to provide an indication of the desired characteristic of said gear as a function of said displacement, linear drive means carried by said base member for providing linear movement of said measuring means proportionally in response to pulses at the input of said linear drive means, pulse source means comprising pulse generating means the output of which is coupled to the input of said rotating drive means, encoder means coupled to said support means constructed to produce pulses in response to rotational movements of said support means, first rate factoring means also coupled to said encoder, the repetition rate of said pulses from said encoder means being proportional to the rate of rotation of said support means, the input of said first rate factoring means being coupled to receive said pulses from said encoder means as input pulses and constructed to provide a series of output pulses to the input of said linear drive means, first control means coupled to said first rate factoring means for selectively controlling the ratio of the pulse repetition rates of said input pulses to said first rate factoring means and said output pulses from said first rate factoring means, wherein said fixed portion of said measuring means is driven by said linear drive means along a linear path representing an errorless gear characteristic and said movable element and said signal means provide an indication of errors in said gear characteristic as said gear is rotatably driven, recording means having a recording medium for recording the output of said signal means which is representative of said errors in said gear characteristic, including recording drive means for driving the recording medium of said recording means comprising second rate factoring means for supplying output pulses to said recording drive means at a rate appropriate for the gear characteristic that is being measured, said second rate factoring means having its input coupled to said pulse source means so as to receive a sequence of the pulses that are developed in said pulse source means as input pulses.