Device for the manual start-up of a plasma torch

In a plasmatron having an anode and cathode spaced from each other so as to sustain an arc therebetween, a nozzle disposed forwardly of the anode and cathode, and means to supply a stream of gas under pressure which flows between the anode and cathode and out of the nozzle, a manual start-up device comprising an electrically conductive plunger constituting a start-up electrode slidably mounted in and in electrical contact with a first one of said anode and cathode for selective advance movement toward and retraction from the second one of said anode and cathode, a first resilient means opposing the advance of the start-up electrode toward the second one of said anode and cathode, whereby to create an arc when the start-up electrode is retracted, away from the second one of said anode and cathode, from its fully advanced position, means mounting the start-up electrode, said start-up electrode mounting means being rotatable to a limited degree when it is in its retracted position, means automatically releasably locking the start-up electrode into its retracted position comprising a second resilient means constantly urging the start-up electrode mounting means and the electrode toward the terminus of their rotation wherein the start-up electrode mounting means and the start-up electrode are locked against axial movement, the means mounting the start-up electrode having an electrically insulated manually engageable means, whereby the start-up electrode mounting means and the start-up electrode may be turned against the action of the second resilient means to a position in which they are free for axial movement toward the second one of said anode and cathode.