PURPOSE: A seam tracking sensor is provided to prevent a worker from being damaged caused by harmful gas, current and light having strong intensity during a welding process by installing the seam tracking sensor utilizing a strain gauge. CONSTITUTION: A bearing bracket(100f) is assembled into an upper portion of a seam tracking rod(100d). An X-plate strain gauge(110a) is attached to both sides of an X-plate installing block(110). An end of the seam tracking rod(100d) is fixed to a center of the X-plate installing block(110). A bearing bracket(100f') having a bearing(100e') therein is assembled to a Y-plate installing block centering shaft(130b). An X-plate strain wire(140b) is positioned between the X-plate strain gauge(110a) and an X-plate elastic plate(140). A Y-plate strain wire(150b) is positioned between the Y-plate strain gauge(130a) and an Y-plate elastic plate(150). An X-plate measuring resistance wire(140a) and a Y-plate measuring resistance wire(150a) are connected to an MS connector.
