Current and frequency control system for electrical discharge machining apparatus

Claim 2

In an electrical discharge machining apparatus operable to provide machining power pulses of independently variable current and frequency across a machining gap; a current control system including a plurality of different magnitude resistors connectable in series with said gap; a first switching means presettable to provide a predetermined pulse frequency; a second switching means presettable to provide a predetermined gap current; and means for combining signals representative of both the aforesaid settings and deriving a control output for connecting Different ones of said resistors in series with the gap to provide a maximum gap current level corresponding to each frequency setting; said means for combining signals comprising a plurality of gating means connected in cascade and operable to provide said output to maintain the desired current level.

Claim 3

The combination as set forth in claim 1 wherein said switching means comprise a pair of deck switches, each selectively positionable in accordance with the selected pulse frequency and pulse current, respectively.

Claim 4

The combination as set forth in claim 1 wherein a plurality of independently actuable relays are included for controlling the connection of said resistors with the gap.

Claim 5

The combination as set forth in claim 1 wherein said gating devices are of the integrated circuit type incorporating resistor-transistor logic elements.

Claim 6

An electrical discharge machining apparatus including means for providing machining power pulses of independently variable current magnitude and frequency to a machining gap, a current control system including: a plurality of resistors selectively connectable in series with said gap; a pulsing means for generating said power pulses including a first switching means presettable to provide a predetermined pulse frequency and a second switching means presettable to provide a predetermined gap current magnitude; means for combining signals representative of both the aforesaid settings comprising, a plurality of gating devices operably connected in sequence; a plurality of relays, each corresponding to one of said resistors and controlling its series connection with said gap; and means connected to the output of said combining means for providing a control output to said relays for actuating them to provide a maximum current level for each different frequency and current setting.

Claim 7

An electrical discharge machining apparatus including means for providing machining power pulses of independently variable current magnitude and frequency to a machining gap, a current control system including: a plurality of resistors selectively connectable in series with said gap; a pulsing means for generating said power pulses including a first switching means presettable to provide a predetermined pulse frequency and a second switching means presettable to provide a predetermined gap current magnitude; means for combining signals representative of both the aforesaid settings comprising, a plurality of gating devices operably connected in sequence; a plurality of relays, each corresponding to one of said resistors and controlling its series connection with said gap; and means connected to the output of said combining means for providing a control output to said relays for actuating them to provide a maximum current level for each different frequency and current setting.

Claim 8

The combination as set forth in claim 5 wherein said pulsing means comprises an astable multivibrator, said multivibrator including a pair of alternately operated switches, each having connected to it a variable resistor-capacitor network, wherein said first switching means is operable to select the capacitor magnitude and wherein said second switch is operable to select the resistor magnitude.

Claim 9

A combination as set forth in claim 5 wherein both said first and second switching means comprise a deck type manually positionable switch.

Claim 10

The combination as set forth in claim 5 wherein each of said gating devices is of the integrated circuit type and of the resistor-transistor configuration.

Claim 11

An electrical discharge machining apparatus operable to provide machining power pulses of independently adjustable current and frequency, the combination comprising: an electric output switch having one of its principal electrodes operatively connected to the machining gap; a current control system including a plurality of resistors selectively connectable in series with said machining gap and said principal electrode; pulsing means for operating said electronic switch; a first switching means connected to said pulsing means and presettable to provide a predetermined pulse frequency for said pulsing means; a second switching means connected to said pulsing means and presettable to provide a predetermined pulse current for said pulsing means; and a means for combining signals representative of both the aforesaid settings and providing a control output for connecting different ones of said resistors to provide a maximum gap current level corresponding to each frequency setting said signal combining means comprising a plurality of gating devices connected in cascade and operable to provide said control output to maintain the desired level of current magnitude.

Claim 12

An electrical discharge machining apparatus operable to provide machining power pulses of independently adjustable current and frequency, the combination comprising: an electric output switch having one of its principal electrodes operatively connected to the machining gap; a current control system including a plurality of resistors selectively connectable in series with said machining gap and said principal electrode; pulsing means for operating said electronic switch; a first switching means connected to said pulsing means and presettable to provide a predetermined pulse frequency for said pulsing means; a second switching means connected to said pulsing means and presettable to provide a predetermined pulse current for said pulsing means; and a means for combining signals representative of both the aforesaid settings and providing a control output for connecting different ones of said resistors to provide a maximum gap current level corresponding to each frequency setting said signal combining means comprising a plurality of gating devices connected in cascade and operable to provide said control output to maintain the desired level of current magnitude.

Claim 13

The combination as set forth in claim 9 wherein a plurality of relays are included for connecting said resistors in series with the gap and said electronic output switch principal electrode.

Claim 14

In an electrical discharge maChining power supply operable to provide machining power pulses of independently variable frequency and current magnitude to the gap, a current control system comprising: a first means presettable to provide a predetermined pulse frequency; a second means presettable to provide a predetermined gap current magnitude; a read-out means operatively connected to said first and second means for providing a signal representative of their respective settings; said read-out means comprising a deck switch corresponding to each of said first and second means and positioned in accordance therewith; means for combining the aforesaid signals and providing a control output signal; and a variable impedance means connected in series with said gap and controlled by said control output signal for maintaining a maximum current level corresponding to each combination of frequency and current magnitude setting said means for combining signals comprising a plurality of gating devices of the resistor-transistor logic type connected in cascade.

Claim 15

In an electrical discharge maChining power supply operable to provide machining power pulses of independently variable frequency and current magnitude to the gap, a current control system comprising: a first means presettable to provide a predetermined pulse frequency; a second means presettable to provide a predetermined gap current magnitude; a read-out means operatively connected to said first and second means for providing a signal representative of their respective settings; said read-out means comprising a deck switch corresponding to each of said first and second means and positioned in accordance therewith; means for combining the aforesaid signals and providing a control output signal; and a variable impedance means connected in series with said gap and controlled by said control output signal for maintaining a maximum current level corresponding to each combination of frequency and current magnitude setting said means for combining signals comprising a plurality of gating devices of the resistor-transistor logic type connected in cascade.

Claim 16

The combination as set forth in claim 11 wherein said variable impedance means comprises a plurality of resistors selectively connectable in circuit with said gap.

Claim 17

The combination as set forth in claim 12 wherein a plurality of relays, each corresponding to at least one of said resistors, are connected between said gating devices and said gap for connecting said resistors to said gap.

Claim 18

In an electrical discharge machining apparatus operable to provide machining power pulses of variable frequency and on-time to the gap, a current control system comprising: a first means presettable to provide a predetermined pulse frequency; a second means presettable to provide predetermined pulse on-time; a read-out means operatively connected to said first and second means for providing a signal representative of their respective settings; means for combining the aforesaid signals to provide a control output signal comprising a plurality of gating devices connected in cascade; and a variable impedance means connected in series with said gap and controlled by said control output signal for maintaining a maximum current level corresponding to each preset combination of frequency and on-time setting.

Claim 19

In an electrical discharge machining apparatus operable to provide machining power pulses of variable frequency and on-time to the gap, a current control system comprising: a first means presettable to provide a predetermined pulse frequency; a second means presettable to provide predetermined pulse on-time; a read-out means operatively connected to said first and second means for providing a signal representative of their respective settings; means for combining the aforesaid signals to provide a control output signal comprising a plurality of gating devices connected in cascade; and a variable impedance means connected in series with said gap and controlled by said control output signal for maintaining a maximum current level corresponding to each preset combination of frequency and on-time setting.