Plasma cutter with integrated air compressor

• US 6,444,944 B2
• Filed: 02/20/2001
• Issued: 09/03/2002
• Est. Priority Date: 09/28/1999
• Status: Expired due to Fees

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Bunker, Thomas A., Schneider, Joseph C.
• Primary Examiner(s): Paschall, Mark
• Application Number:
  US09/788,881
• Publication Number:
  US 20010042736A1
• Time in Patent Office: 560 Days
• Field of Search: 219/121.54, 219/121.55, 219/121.48, 219/121.57, 219/121.39, 219/121.44, 219/74-75
• US Class Current: 219/121.54
• CPC Class Codes: B23K 10/00 Welding or cutting by means of a plasma

Abstract

A method and apparatus for plasma cutting includes a cutting power supply, preferably a buck converter, and a compressor. The cutting power supply provides power to a plasma torch, and the compressor provides air to the torch. The air compressor is integrated into the plasma cutter, and includes a compressor motor, preferably with a buck convertor power supply, or having the motor windings are part of the buck converter that is the cutting power supply. The motor is regulated regulator to a fixed setpoint or a user setpoint by a compressor regulator in response to a feedback signal, preferably a compressor motor voltage feedback signal. The compressor also turns the compressor on and/off in response to a trigger and/or cutting current feedback signal and has an on/off circuit responsive thereto in various alternatives. The cutting power controller and the compressor regulator are part of an integrated controller, and/or the cutting power supply and the air compressor are in a common housing, and/or the cutting power supply and the air compressor have an integrated power supply.

Claims

1. A plasma cutter comprising:

a cutting power supply disposed to provide power to a plasma torch;

an air supply, disposed to provide air to the plasma torch, wherein the air supply is integrated into the plasma cutter; and

an air supply regulator disposed to receive a feedback signal, and further disposed to regulate the air supply in response to the feedback signal;

wherein the air supply regulator is further disposed to receive a plasma current feedback signal, and includes an on/off circuit responsive to the plasma current feedback signal.

2. The apparatus of claim 1, wherein the air supply regulator further includes a fixed setpoint, and further includes a regulator circuit having as inputs the fixed setpoint and the feedback signal.

3. The apparatus of claim 2, wherein the feedback signal is a voltage feedback signal.

4. The apparatus of claim 1, further comprising a cutting power controller disposed to receive a trigger signal, a set point and a cutting power feedback signal, and disposed to provide a cutting power control signal in response to the trigger signal, the set point and the cutting power feedback signal.

5. The apparatus of claim 4, wherein the cutting power controller and the air supply regulator are part of an integrated controller, whereby the air supply is integrated into the plasma cutter by having an integrated controller.

6. The apparatus of claim 1 wherein the plasma cutter includes a housing, and the cutting power supply and the air supply are disposed in the housing, whereby the air supply is integrated into the plasma cutter by having an integrated housing.

7. The apparatus of claim 1, wherein the cutting power supply is disposed to provide power to the air supply whereby the air supply is integrated into the plasma cutter by having an integrated power supply.

9. The apparatus of claim 1, wherein the regulator means further includes means for turning the air supply means on and off in response to a plasma current feedback signal.

8. A plasma cutter comprising:

a cutting power supply disposed to provide power to a plasma torch; and

an air compressor disposed to provide air to the plasma torch, wherein the air compressor is integrated into the plasma cutter, and wherein the air compressor includes an air compressor motor;

wherein the cutting power supply includes a buck convertor, connected to a cutting winding, and having a switch and an inductive element, and wherein the air compressor motor is at least part of the inductive element.

10. A plasma cutter comprising:

cutting means for providing power to a plasma torch;

air supply means for providing air to the plasma torch, wherein the air supply means is integrated into the plasma cutter; and

a regulator means for receiving a feedback signal and for regulating the air supply in response to the feedback signal, wherein the regulator means further includes a fixed setpoint, and includes a regulator circuit means for comparing the fixed setpoint and a voltage feedback signal.

12. The apparatus of claim 10, wherein the plasma cutter includes a housing, and the cutting power supply means and the air supply means are disposed in the housing, whereby the air supply means is integrated into the plasma cutter by having an integrated housing.

13. The apparatus of claim 10, wherein the cutting power supply means is further for providing power to the air supply means, whereby the air supply means is integrated into the plasma cutter by having an integrated power supply.

11. A plasma cutter comprising:

cutting means for providing power to a plasma torch;

air supply means for providing air to the plasma torch, wherein the air supply means is integrated into the plasma cutter;

a regulator means for receiving a feedback signal and for regulating the air supply in response to the feedback signal; and

a cutting power controller means for controlling the cutting power in response to a fixed set point and a cutting power feedback signal, and wherein the cutting power controller means and the regulator means are part of an integrated controller, whereby the air supply is integrated into the plasma cutter by having an integrated controller.

14. A plasma cutter comprising:

cutting means for providing power to a plasma torch; and

air supply means for providing air to the plasma torch, wherein the air supply means is integrated into the plasma cutter, and wherein the air supply means includes a motor;

wherein the cutting power supply means includes a buck convertor, connected to a cutting winding, and having a switch and an inductive element, and the motor is at least part of the inductive element.

15. A method of plasma cutting comprising:

providing plasma cutting power to a plasma torch with a cutting power supply;

supplying air from an air supply integrated into the plasma cutter;

providing the air to the plasma torch; and

regulating the air supply in response to a feedback signal; and

turning on and off the air supply motor in response to a trigger signal.

16. The method of claim 15, further including turning on and off the air supply in response to a plasma current feedback signal.

17. The method of claim 16, wherein regulating includes comparing a voltage feedback signal to a fixed setpoint.