Patent ID: 7766305

Claim:
A rectangular gate valve, comprising: a sealing member for opening and closing a wafer moving passage; a main shaft coupled at an upper end thereof to the sealing member, with a guide member protruding from a sidewall of the main shaft; a housing bracket, having therein a first guide slot, which is vertically formed in the housing bracket, and into which the guide member of the main shaft is inserted; a valve drive unit provided in the housing bracket, and comprising: an air cylinder to be operated by pressure of air; a piston provided in the air cylinder; a piston shaft coupled to the piston; a moving unit coupled to the piston shaft; and a connection link connected between the moving unit and the main shaft; a guide bracket, comprising: a vertical bracket extending downwards from a lower surface of the housing bracket, with a second guide slot formed in a longitudinal surface of the vertical bracket; and a horizontal bracket coupled to a lower end of the vertical bracket; and a guide link coupled at a first end thereof to a circumferential outer surface of the main shaft and inserted at a second end thereof into the second guide slot, the guide link being moved along the second guide slot to guide movement of the main shaft, wherein the second guide slot comprises a vertical straight portion and a cane-shaped upper end portion, wherein the vertical straight portion is parallel to the first guide slot, and wherein the vertical straight portion of the second guide slot is connected to the first guide slot with the cane-shaped upper end portion of the second guide slot, so as to obtain an L-shaped two-stepped driving action of the main shaft.