Patent ID: 7687739

Claim:
A seal structure sealing an opening formed at a side wall of a machining tank of a wire-cut electric discharge machine in which an upper arm and a lower arm support a wire electrode, and the lower arm extends through the opening into the machining tank containing machining fluid, said seal structure comprising: a first seal provided along a periphery of said opening; and a second seal having a hole through which the lower arm extends and pressed against said first seal to be in contact with said first seal to cover said opening, said first seal having two or more ridges and one or more grooves between the ridges along an extending direction thereof on a side in contact with said second seal, and one or more passages extending between at least one of the grooves and the exterior of said first seal, said one or more passages providing drainage paths for the machining fluid to control routes of leakage of the machining fluid outside the machining tank.