Automatic flute grinding machine

The method of indexing the work spindle in a spiral grinding machine having a reciprocable carriage and a rotated work spindle travelling therewith, together with separate binary pulse-activated motors for driving the carriage and spindle, said method comprising, namely:

• travelling the carriage by a corresponding motor in a first forward working pass while rotating the spindle by the other motor;
• operating a forward limit switch by the carriage at the completion of said first pass;
• stopping the spindle motor only and reversing travel of the carriage back to a home position as the result of said limit switch operation;
• operating a home limit switch by the carriage and causing restarting the carriage forward on a further working pass;
• counting the binary drive pulses for the carriage and comparing said count with an index distance binary count determined by presetting a digital to binary index distance switch and restarting the spindle rotation on detection of equation between the compared counts, said index distance switch producing binary pulses in accordance with the presetting thereof which constitutes the additional number of pulses required to turn the work piece into a predetermined newly-indexed starting position relative to a working tool which is a predetermined angular distance away from the angular position on the work piece last engaged by the tool in the preceding pass.

In a spiral grinding machine the combination with a carriage reciprocable between an advanced and a home position and carrying a rotary work spindle adapted to hold work for movement relative to a grinding wheel carried by a tool head, of separate motors driving the carriage and spindle reversely under control of digitally-coded binary pulses including presettable digital to binary coding ratio switch means operative to change the speed ratio between said motors;

• pass-counting digital to binary switch means operative to determine a set number of working passes of the carriage;
• index-pulse digital-top binary switch means operative to rotate the spindle to predetermined angular indexing positions in successive carriage passes following a first such pass;
• limit switch means operable by the carriage in forward and home positions;
• logic subcircuit means including duty-cycle starting and terminating means and connections with said limit switch means and operative to cause said carriage to make a preset number of working passes from home position and return thereto, and to index the spindle a preset number of times as a function of return of the carriage to home position in successive working passes thereof following a first such pass in a given duty cycle;
• together with drivepulse counting means and index logic means operative responsive to operation of the forward limit switch means as aforesaid to stop the spindle rotation and restart said rotation in each indexing operation dependently upon the setting of said index-pulse switch means and comparison of resultant binary pulses therefrom with the counted number of drive pulses sensed following said reversal of the carriage in the appertaining indexing operation, such that the restarting of the spindle as aforesaid will rotate the spindle on restarting to lodge the work in a certain indexed angular starting position relative to said grinding wheel different from the position thereof at the time the spindle is stopped, the angular magnitude of which corresponds to the setting in terms of index pulses of said digital index pulses switch means.

A spiral grinding machine including a reciprocable carriage slide and a work spindle carried thereby for travel relative to a grinding tool in successive working passes from a home starting position of the carriage to predetermined advanced stopping positions;

• first motor means operative to travel the carriage slide between said positions;
• first circuit means operative to cause said first motor means to drive said carriage slide to make a preselected number of working passes;
• second motor means operative to rotate said spindle during carriage travel as aforesaid;
• second circuit means operative to stop said spindle rotation for indexing on arrival of the carriage slide at said advanced position and to restart said spindle in indexed rotation prior to advance of the carriage slide in each succeeding working pass a distance which would bring the work into reengagement with said grinding tool;
• third circuit means operative to index the work spindle by restarting rotation thereof in steps aggregating a predetermined angular index amount in each working pass following the first and following the time of stoppage of the spindle rotation as aforesaid, but prior to the arrival of the carriage slide at such a position as would cause the work to reengage said tool before said indexing rotation is completed;
• and fourth circuit means including an indexing switch presettable to determine the number of said aggregate spindle indexing steps required to reengage the work with the grinding tool at a point exactly equivalent to said predetermined angular index amount.

A machine for abrading and grinding of the type in which a rotary work spindle is carried between predetermined starting and working positions by a reciprocable carriage to travel work carried by the spindle relative to an abrading, grinding or the like tool, and in which means is provided for automatically indexing the spindle to predetermined angular index positions to start the work in one or more additional working passes in predetermined angular index positions, characterized in that the spindle and carriage are driven by corresponding pulse-controlled motors actuated by circuit means operative to predetermine the number of times the carriage is to move to and from a predetermined advanced working position and the number of times the work spindle is to be indexed, together with the relative speed ratios of spindle and carriage movement in the forward working advance, at least;

• said circuit means being further operative to stop the spindle on each arrival of the carriage at a preselected forward working position and thereupon to effect withdrawal of the carriage from said forward position substantially, concomitantly with such stoppage and restarting of the carriage toward working position for a preset number of additional index passes;
• together with indexing subcircuit means including index distance control and pass means operative to restart rotation of the spindle in step with the carriage position in each indexing operation, whereby the work is presented to the tool in that angular position thereof which is exactly at the preset index position.