Device for feeding welding wire in a submerged arc welding operation

Abstract

A device for feeding welding wire in a submerged arc welding operation in which there is a narrow gap between workpieces which are to be welded together comprises a guide support having a plurality of spaced apart welding wire straightening roller assemblies mounted thereon which are in a position at selected angles relative to each other around and in engagement with the welding wire and which define a feed guide path for the passage of the welding wire between the rollers of each assembly. A welding head is pivotally mounted on a support for pivotal movement transverse to the welding direction and the head includes a welding guide and a carrying guide which together define tongs of the head which are mounted on the support for pivotal movement toward and away from each other. Tongs carry a plurality of guide shoes which define a continuing guide path for the welding wire received from the welding wire feed guide and deliver it to the welding zone between the workpieces. A contact piece associated with the current carrying guide provided current for the welding operation. Means are provided for biasing the current guide toward the welding wire guide. The construction preferably includes at least three straightening roller assemblies with at least three roller assembly elements which are rotatable relative to each other in a direction around the periphery of the wire which they cooperate to guide and straighten. The welding head advantageously includes welding guide blade and a current carrying guide blade which are pivotally mounted on a hinge bolt. Straightening roller units are carried in a cylindrical roller housing on the support. Each of the roller housings comprises a substantially tubular shell which is designed with an upper inside recess and with a lower centering extension to be snugly fitted into the recess of each following roller housing. The extension is provided with an outer circular groove and can be clamped in position by means of fixing screws.