Nitrogen protection device for circuit board welding machine

The invention relates to the field of welding machines, and particularly relates to a nitrogen protection device for a circuit board welding machine. The nitrogen protection device for the circuit board welding machine comprises a nitrogen spray head with an output end facing a gun head of the welding machine, a nitrogen supply pipe used for conveying nitrogen to the nitrogen spray head, a check valve assembly arranged between the nitrogen spray head and the nitrogen supply pipe, and a support device used for fixing the nitrogen spray head, wherein an input end of the check valve assembly is connected with an output end of the nitrogen supply pipe through a pipeline; an output end of the check valve assembly is connected with an input end of the nitrogen spray head through a pipeline; andthe nitrogen spray head is movably installed on the support device. Through the mutual cooperative working among the check valve assembly, a support assembly of the support device, a lifting assembly,and a rotating assembly,