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A threaded connection for an electrode holder and an electrode in a plasma arc torch is provided. The threaded connection has relatively low height, and the engaged portion of a male threaded portion of the electrode and a female threaded portion of the electrode holder are positioned at least parti

A threaded connection for an electrode holder and an electrode in a plasma arc torch is provided. The threaded connection has relatively low height, and the engaged portion of a male threaded portion of the electrode and a female threaded portion of the electrode holder are positioned at least partially within a nozzle chamber. In one inventive aspect, the nominal pitch diameter of the electrode is less than the minor diameter of the electrode. In another, the width of the root area of the electrode thread is wider than the width of the root area of the electrode holder thread by at least about 35%. The width of the root area of the electrode is at least about 15% wider than the width of the crest portion of the electrode. As such, the less consumable of the two parts, the electrode holder, is provided with a thread that is less likely to be worn and damaged. In one particular embodiment, the crest profile of the electrode is that of a Stub Acme thread separated by a larger root profile.

대표청구항 ▼

What is claimed is: 1. An electrode for emitting an arc of a plasma torch and for being removably held in the plasma arc torch, the electrode comprising: a male threaded portion for removably holding the electrode in the plasma arc torch and defining at least one thread form extending helically and

What is claimed is: 1. An electrode for emitting an arc of a plasma torch and for being removably held in the plasma arc torch, the electrode comprising: a male threaded portion for removably holding the electrode in the plasma arc torch and defining at least one thread form extending helically and at least partially around a thread axis, the threaded portion defining; a major diameter comprising a larger diameter of the threaded portion, a minor diameter comprising a smaller diameter of the threaded portion, a pair of flanks defining one or more crest profiles when viewed in cross section and extending between the major diameter and the minor diameter, wherein each of the flanks of a crest profile defines at least one line that intersects at a crest apex with a line defined by the other of the flanks of that thread crest profile, and further wherein at least one of those lines intersects at a root apex with a line defined by a flank on an opposite side of the root apex, and a nominal pitch diameter defined halfway between the diameter of the crest apex and the diameter of the root apex; wherein the nominal pitch diameter is not greater than the minor diameter. 2. An electrode as defined in claim 1 wherein the nominal pitch diameter is smaller than the minor diameter. 3. An electrode and electrode holder for a plasma arc torch, the electrode being removably held by the electrode holder in a threaded connection and comprising: an electrode holder having a female threaded portion defining at least one thread form extending helically and at least partially around a thread axis, the female threaded portion defining; a major diameter comprising a larger diameter of the female threaded portion, a minor diameter comprising a smaller diameter of the female threaded portion, an electrode having a male threaded portion defining at least one thread form for threadedly engaging the female threaded portion of the electrode holder, the male threaded portion defining; a major diameter comprising a larger diameter of the male threaded portion, a minor diameter comprising a smaller diameter of the male threaded portion, a pair of flanks defining one or more crest profiles when viewed in cross section and extending between the major diameter and the minor diameter, wherein each of the flanks of a crest profile defines at least one line that intersects at a crest apex with a line defined by the other of the flanks of that crest profile, and futher wherein at least one of the lines intersects at a root apex with a line defined by a flank on an opposite side of the root apex, and a nominal pitch diameter defined halfway between the diameter of the crest apex and the diameter of the root apex; wherein the nominal pitch diameter of the electrode is not greater than the minor diameter of the electrode holder. 4. An electrode as defined in claim 3 wherein the nominal pitch diameter of the electrode is smaller than the minor diameter of the electrode holder. 5. An electrode holder for removably holding an electrode in a plasma arc torch, the electrode holder comprising: a male threaded portion for removably holding the electrode holder in the plasma arc torch and defining at least one thread form extending helically and at least partialiy around a thread axis, the threaded portion defining; a major diameter comprising a larger diameter of the threaded portion, a minor diameter comprising a smaller diameter of the threaded portion, a pair of flanks defining one or more crest profiles when viewed in cross section and extending between the major diameter and the minor diameter, wherein each of the flanks of a crest profile defines at least one line that intersects at a crest apex with a line defined by the other of the flanks of that crest profile, and further wherein at least one of those lines intersects at a root apex with a line defined by a flank on an opposite side of the root apex, and a nominal pitch diameter defined halfway between the diameter of the crest apex and the diameter of the root apex; wherein the nominal pitch diameter is not greater than the minor diameter. 6. An electrode holder as defined in claim 5 further comprising: a female threaded portion separate from the male threaded portion for removably holding the electrode to the electrode holder and defining at least one thread form extending helically and at least partially around a female thread axis, the female threaded portion defining; a major diameter comprising a larger diameter of the female threaded portion, a minor diameter comprising a smaller diameter of the female threaded portion, a pair of flanks defining one or more crest profiles when viewed in cross section and extending between the major diameter and the minor diameter, wherein each of the flanks of a crest profile defines at least one line that intersects at a crest apex with a line defined by the other of the flanks of that thread crest profile, and further wherein at least one of those lines intersects at a root apex with a line defined by a flank on an opposite side of the root apex, and a nominal pitch diameter defined halfway between the diameter of the crest apex and the diameter of the root apex; wherein the nominal pitch diameter of the female threaded portion is smaller than the major diameter of the female threaded portion. 7. An electrode holder as defined in claim 6 wherein the nominal pitch diameter of the female threaded portion is larger than the minor diameter of the female threaded portion. 8. An electrode and electrode holder for a plasma arc torch, the electrode being removably held by the electrode holder in a threaded connection and comprising: an electrode holder having a threaded portion defining at least one thread form extending helically and at least partially around a thread axis, the threaded portion defining; a major diameter comprising a larger diameter of the threaded portion, a minor diameter comprising a smaller diameter of the threaded portion, a mean diameter between the major diameter and the minor diameter, a crest portion extending in one direction from the mean diameter, a root area extending in an opposite direction from the mean diameter than the crest portion and defining a width along the mean diameter, and an electrode having a threaded portion defining at least one thread form for threadedly engaging the threaded portion of the electrode holder, the threaded portion defining; a major diameter comprising a larger diameter of the threaded portion, a minor diameter comprising a smaller diameter of the threaded portion, a mean diameter between the major diameter and the minor diameter, a crest portion extending in one direction from the mean diameter, a root area extending in an opposite direction from the mean diameter than the crest portion and defining a width along the mean diameter, and wherein the width of the root area of the electrode is at least about 35% wider than the root area of the electrode holder. 9. An electrode and electrode holder as defined in claim 8 wherein the root area of the electrode is at least about 45% wider than the root area of the electrode holder. 10. An electrode and electrode holder as defined in claim 9 wherein the root area of the electrode is at least about 55% wider than the root area of the electrode holder. 11. An electrode for emitting an arc of a plasma arc torch and for being removably held to the plasma arc torch, the electrode comprising: a threaded portion for removably holding the electrode in the plasma arc torch and defining at least one thread form extending helically and at least partially around a thread axis, said treaded portion defining; a major diameter comprising a larger diameter of the threaded portion, a minor diameter comprising a smaller diameter of the threaded portion, a mean diameter between the major diameter and the minor diameter, a crest portion extending in one direction from the mean diameter and defining a width along the mean diameter, and a root area extending in an opposite direction from the mean diameter than the crest portion and defining a width along the mean diameter, and wherein the width of the root area is at least about 15% greater than die width of the crest portion. 12. An electrode as defined in claim 11 wherein the root area of the electrode is at least about 55% wider than the crest portion. 13. An electrode as defined in claim 12 wherein the root area of the electrode is at least about 95% wider than the crest portion. 14. An electrode bolder for holding an electrode of a plasma arc torch and for being removably held to the plasma arc torch, the electrode holder comprising: a threaded portion for removeably holding the electrode holder in the plasma arc torch and defining at least one thread form extending helically and at least partially around a thread axis, said threaded portion defining; a major diameter comprising a larger diameter of the threaded portion, a minor diameter domprising a smaller diameter of the threaded portion, a mean diameter between the major diameter and the minor diameter, a crest portion extending in one direction from the mean diameter and defining a width along the mean diameter, and a root area extending in an opposite direction from the mean diameter than the crest portion and defining a width along the mean diameter, and wherein the width of the root area is at least about 15% greater than the width of the crest portion. 15. An electrode holder as defined in claim 14 wherein the root area of the electrode holder is at least about 55% wider than the crest portion. 16. An electrode holder as defined in claim 15 wherein the root area of the electrode holder is at least about 95% wider than the crest portion. 17. An electrode and electrode holder for a plasma arc torch, the electrode being removably held by the electrode holder in a threaded connection and comprising: an electrode holder having a female threaded portion defining at least one thread form extending helically and at least partially around a thread axis, the threaded portion defining in cross section; a plurality of alternating crests and roots, the axial distance between corresponding points on two adjacent crests or roots defining a pitch; wherein at least one of the crests between adjacent roots defines a crest flat, and wherein the crest flat has a width in the axial direction that is greater than 0.4224 times the pitch; and an electrode having a male threaded portion defining at least one thread form for threadedly engaging the female threaded portion of the electrode holder, the threaded portion defining in cross section; a plurality of alternating crests and roots, wherein at least one the crests between adjacent roots defines a crest flat, and wherein the crest flat has a width in the axial direction that is less than width of the crest flat of the electrode holder. 18. An electrode and electrode holder as defined in claim 17 wherein the crest flat of the electrode is not greater than 0.4224 times the pitch. 19. An electrode for emitting an arc of a plasma torch and for being removably held in the plasma arc torch, the electrode comprising: a male threaded portion for removably holding the electrode in the plasma arc torch and defining at least one thread form extending helically and at least partially around a thread axis, the threaded portion defining in cross section; a plurality of alternating crests and roots, the axial distance between corresponding points on two adjacent crests or roots defining a pitch; wherein at least one of the roots between adjacent crests defines a root flat, and wherein the root flat defines a width in the axial direction that is greater than 0.4224 times the pitch. 20. An electrode holder for holding an electrode in a plasma arc torch, the electrode holder comprising: a male threaded portion for removably holding the electrode holder in the plasma arc torch and defining at least one thread form extending helically and at least partially around a thread axis, the threaded portion defining in cross section; a plurality of alternating crests and roots, the axial distance between corresponding points on two adjacent crests or roots defining a pitch; wherein at least one of the roots between adjacent crests defines a root flat, and wherein the root flat defines a width in the axial direction that is greater than 0.4224 times the pitch. 21. An electrode for emitting an arc of a plasma torch and for being removably held in the plasma arc torch, the electrode comprising: a male threaded portion for removably holding the electrode within the plasma arc torch and defining at least one thread form extending helically and at least partially around a thread axis, the threaded portion defining; a major diameter comprising a larger diameter of the threaded portion, a minor diameter comprising a smaller diameter of the treaded portion, a pair of flanks defining one or more crest profiles when viewed in cross section and extending between the major diametet and the minor diameter, wherein each of the flanks of a crest profile defines at least one line that intersects at a crest apex with the line defined by the other of the flanks of that thread crest profile, and further wherein at least one of those lines intersects at a root apex with a line defined by a flank on an opposite side of the root apex; and a nominal pitch diameter defined halfway between the diameter of the crest apex and the diameter of the root apex; wherein the nominal pitch diameter is not greater than about 105% of the minor diameter.