Abstract: A sheet cutter for cutting a sheet with a cutting blade held by a cutting blade elevating body which is elevated by one servo motor, including a pair of cutting blade elevating bodies; an elevation driving body for elevating the pair of cutting blade elevating bodies; a guide member for guiding the elevation of the pair of cutting blade elevating bodies; a holding body capable of holding the pair of cutting blade elevating bodies at an up position; and a transmission change-over device for selectively engaging the pair of cutting blade elevating bodies with the elevation driving body and selectively disengaging the pair of cutting blade elevating bodies from the elevation driving body, wherein one of the pair of cutting blade elevating bodies, which has been selected, is elevated by the servo motor.

Abstract: There is provided a sheet cutter capable of cutting a sheet into a rectangle, the side lengths of which are different, with two cutting blades, characterized in that: the cutting blade elevating section is downsized; the cutting accuracy is high; and the cutting speed is increased. A transmission change-over device is provided so that one of the pair of cutting blade elevating bodies 2, 2, which are provided being put on each other in the longitudinal direction, can be connected to the elevation driving body 10 elevating by the rotation of the feed screw shaft 11. The transmission change-over device includes: an engaging piece 13 provided in an upper portion of the cutting blade elevating body 2; a connecting pin 15 for connecting the elevation driving body 10 with the engaging piece 13; a push-out pin 17a for moving the connecting pin 15; a push-in pin 17b for moving the connecting pin 15; and a holding member 19 for holding one of the cutting blade elevating body 2 which is not elevated.

Abstract: An improved bar screen is disclosed which has a plurality of ring bars and a plurality of scrapers mounted therebetween which are rockable away from the ring bars. Since base portion of the scrapers is always engaged between the ring bars, the scrapers may be easily reset into their operative position after they have been rotated to their cleaning position away from the ring bars.