Positioning device and positioning assembly for holding a flat flexible part, and sheet material processing machine

A positioning device for holding a flat flexible part on a positioning surface, the positioning device comprising:

• a body with a fluid inlet port for supplying a driver fluid to the body, a fluid outlet port for draining the driver fluid from the body, and a suction opening for aspiring the flat flexible part, wherein the suction opening is arranged within the positioning surface being an outer surface of the body,
• a circulation channel connecting the fluid inlet port and the fluid outlet port, wherein the circulation channel comprises a section of reduced cross section area, and
• a suction channel connecting the suction opening to the circulation channel, wherein the suction channel is connected to the circulation channel adjacent to the section of reduced cross section area such that a jet pump is formed,
• wherein every cross section of the circulation channel and/or every cross section of the suction channel along its entire respective length has a smooth rim, so that a contour delimiting every cross section of the circulation channel and/or every cross section of the suction channel along its entire respective length does not have corners or kinks, and
• wherein the fluid inlet port and the fluid outlet port are arranged on a same end of the body.