Electrode wear compensating apparatus for an electrical discharge machine

Claim 2

Apparatus for compensating for a decrease in length of an electrode in an electrical discharge machine wherein said electrode carried by an electrode holding means is reciprocably mounted to advance into and retract out of engagement with a work piece, comprising: a limit switch; a lead screw mounted to engage said limit switch when said electrode holding means advances into engagement with the work piece; motor means for moving said lead screw in a direction away from said limit switch; and control means for energizing said motor means to move said lead screw in a direction away from said limit switch by a predetermined distance each time said lead screw engages said limit switch.

Claim 3

Apparatus for compensating for a decrease in length of an electrode in an electrical discharge machine wherein said electrode carried by an electrode holding means is reciprocably mounted to advance into and retract out of engagement with a work piece, comprising: a lead screw threadably mounted through said mounting member; motor means for rotating said lead screw; a limit switch stationarily mounted to be engaged by one end of said lead screw when said electrode holding means approaches its most advanced position; and control means for energizing said motor means to rotate said lead screw by a predetermined amount each time said end of said lead screw contacts said limit switch thereby allowing said electrode holding means to advance a predetermined distance on the next operation.

Claim 4

Apparatus for compensating for a decrease in length of an electrode in an electrical discharge machine wherein said electrode carried by an electrode holding means is reciprocably mounted to advance into and retract out of engagement with a work piece, comprising: a lead screw threadably mounted through said mounting member; motor means for rotating said lead screw; a limit switch stationarily mounted to be engaged by one end of said lead screw when said electrode holding means approaches its most advanced position; and control means for energizing said motor means to rotate said lead screw by a predetermined amount each time said end of said lead screw contacts said limit switch thereby allowing said electrode holding means to advance a predetermined distance on the next operation.

Claim 5

Apparatus for compensating for a decrease in length of an electrode as recited in claim 2 wherein said motor means is a stepper motor.

Claim 6

Apparatus for compensating for a decrease in length of an electrode as recited in claim 3 wherein said control means comprises: oscillator means for generating pulses; means for energizing said oscillator means when said end of said lead screw engages said limit switch; motor drive means for receiving the pulses generated by said oscillator means and driving said stepper motor in response to said pulses; and means for counting the pulses generated by said oscillator means and for de-energizing said oscillator means when a predetermined number of pulses is counted.

Claim 7

Apparatus for compensating for a decrease in length of a consumable electrode in an electrical discharge machine having a base and an electrode carried by a holding means reciprocably mounted to advance into and retract out of engagement with a work piece, a guide member having a first and a second end, said guide member mounted at said first end to said holding means and slidably mounted through said base, comprising: a mounting member mounted on said second end of said guide member; a lead screw threadably mounted through said mounting member; an L-shaped member, the longer leg of said L-shaped member being slidably mounted through said mounting member and substantially parallel to said lead screw, said lead screw being rotatably mounted to the shorter leg of said L-shaped member with said L-shaped member constrained to follow axial movement of said lead screw, said L-shaped member slidably moving through said mounting member in response to movement of said lead screw; motor means for rotating said lead screw; a first limit switch mounted on said base, one end of said lead screw engaging said first limit switch when said holding means approaches its most advanced position; and control means for energizing said motor means to rotate said lead screw by a predetermined amount each time said end of said lead screw engages said first limit switch thereby allowing said holding means to be advanced a predetermined distance on the next operation.

Claim 8

Apparatus for compensating for a decrease in length of a consumable electrode in an electrical discharge machine having a base and an electrode carried by a holding means reciprocably mounted to advance into and retract out of engagement with a work piece, a guide member having a first and a second end, said guide member mounted at said first end to said holding means and slidably mounted through said base, comprising: a mounting member mounted on said second end of said guide member; a lead screw threadably mounted through said mounting member; an L-shaped member, the longer leg of said L-shaped member being slidably mounted through said mounting member and substantially parallel to said lead screw, said lead screw being rotatably mounted to the shorter leg of said L-shaped member with said L-shaped member constrained to follow axial movement of said lead screw, said L-shaped member slidably moving through said mounting member in response to movement of said lead screw; motor means for rotating said lead screw; a first limit switch mounted on said base, one end of said lead screw engaging said first limit switch when said holding means approaches its most advanced position; and control means for energizing said motor means to rotate said lead screw by a predetermined amount each time said end of said lead screw engages said first limit switch thereby allowing said holding means to be advanced a predetermined distance on the next operation.

Claim 9

Apparatus for compensating for a decrease in length of an electrode as recited in claim 5 including: a first and a second member mounted a predetermined distance apart on said longer leg of said L-shaped member; and a second and a third limit switch mounted along the path of said longer leg of said L-shaped member, said second and said third limit switches being engaged by said first and said second members, respectively, to prevent advance and retraction of said holding means beyond predetermined limits.

Claim 10

Apparatus for compensating for a decrease in length of an electrode as recited in claim 6 wherein the position of at least one of said first and second members on said longer leg of said L-shaped member may be adjusted.

Claim 11

Apparatus for compensating for a decrease in length of an electrode as recited in claim 5 wherein said motor means is a stepper motor.

Claim 12

Apparatus for compensating for a decrease in length of an electrode as recited in claim 8 wherein said control means comprises: oscillator means for generating pulses; means for energizing said oscillator means when said end of said lead screw engages said first limit switch; motor drive means for receiving the pulses generated by said oscillator means and driving said stepper motor in response to said pulses; and means for counting the pulses generated by said oscillator means and for de-energizing said oscillator means when a predetermined number of pulses is counted.

Claim 13

Apparatus for compensating for a decrease in length of an electrode as recited in claim 9 wherein said counting means includes a digital switch to vary the predetermined number to which said counting means will count before de-energizing said oscillator means.

Claim 14

Apparatus for compensating for a decrease in length of an electrode as recited in claim 10 wherein said oscillator means includes a frequency divider.