Patent GB-1427675-A (GB)
Title: Arc welding rod electrode holder with means for the withdrawal  of welding fumes
IPC: B08B15/04
Filed: 1974-03-01
Abstract: 1427675 Welding by fusion ESAB Ltd 1 March 1974 [2 March 1973 11 Feb 1974] 9401/74 Heading B3R [Also in Division H5] A consumable arc welding or rod holder is combined with a welding fume withdrawal nozzle unit 31 which, to maintain the nozzle unit at a suitable distance from the arc, is slidably supported on an electrode 11 clamped in the holder and is controllably retracted towards the holder by a rotary motor spring 28 acting on the nozzle unit by way of a reel 18 and a string 19 wound thereon. The holder comprises a tubular handle 1, preferably of electrically and heat insulating material, a front cap 2, a welding current conductor 3 having an electrically insulating sheath 4 and a cable contact socket 5 provided with a welding cable engaging screw 6, and an electrode clamping and contact head 7 provided with an electrode engaging screw 12 and an electrically insulating shield 13 having a lining 14. The head 7 is pivotally connected to the conductor 3 by a screw bolt 8 which serves to fix a desired angular position of the head (and hence the electrode) with respect to the front cap 2 (and hence the handle) said cap being provided with a slot 15 allowing the head/cap angular movement. A compression spring 16 reacting on a handle flange 17 acts, via the socket 5 and conductor 3, to pull the cap 2 towards the handle into a desired cap/handle angular position maintained by engagement of a cap finger (not shown) and one of a plurality of handle detents (not shown) change of cap/ handle angular position being achieved by sequential relative axial separation (against the spring 16), rotation and release of the cap and handle. The reel 18 is rotatably mounted on conductor 3 and carries the string 19 which may be cord, tape, wire cable or metal strip. The string is guided in the cap by a roller 30. The motor spring 28 is connected between the handle flange 17 and the reel 18. A detent ring 22 is connected to the reel by a spring one-way clutch 21 and is provided with four equally angularly spaced detent projections 24a, 25a, 24b, 25b. The projections 24a, 24b alternate with and are axially spaced from the projections 25a, 25b. A spring returned trigger 27 pivotably mounted in the handle has a catch 26 which is engageable with the projections 24a, 24b in the trigger-released position shown, and with the projections 25a, 25b in the triggeractuated position. The nozzle unit 31 comprises an electrode engaging inner sleeve 32, an insulating sleeve 33 and an outer sleeve 48 carrying a bell-shaped nozzle 34 connectible to an extractor fan via an aperture 35 and a flexible conduit (not shown). The string 19 is connected to a detent pin 36 slidable in the nozzle unit and spring-biased into engagement with the electrode. In operation, string winding-up rotation of the reel acts, through clutch 21, to clutch the reel to the ring 22 so that reel rotation is obstructed by the engagement of one of the ring projections with the catch 26. Winding up of the string and hence the nozzle unit is permitted, step-by-step and in quarter turns of the reel, by alternate actuation and release of the trigger effecting withdrawal of the catch 26 respectively and alternately from the paths of the projections 24a, 24b and 25a, 25b. Nozzle unit retraction is terminated by engagement thereof with the head 13, the length of the string being so arranged that at said engagement, the catch 26 is not in engagement with any of the projections of the ring 22 so that electrode removal is not obstructed by the detent pin 36 due to slackness of the string. After clamping of a fresh electrode in the head, the nozzle unit is pulled towards the electrode tip, the taughtened string maintaining withdrawal of the detent pin 36, and the clutch 21 releasing to permit motor-spring- charging rotation of the reel relative to the detained ring 22. In an alternative embodiment, the motor spring acts on the reel indirectly, e.g. through gearing.